Currently, by default, integral curves are repeatedly re-computed in different flow visualization applications, such as FTLE field computation, source-destination queries, etc., leading to unnecessary resource cost. We present a compression-based data reuse framework for integral curves, to greatly reduce their retrieval cost, especially in a resource-limited environment. In our design, a hierarchical and hybrid compression scheme is proposed to balance three objectives, including high compression ratio, controllable error, and low decompression cost. Specifically, we use and combine digitized curve sparse representation, floating-point data compression, and octree space partitioning to adaptively achieve the objectives. Results have shown that our data reuse framework could acquire tens of times acceleration in the resource-limited environment compared to on-the-fly particle tracing, and keep controllable information loss. Moreover, our method could provide fast integral curve retrieval for more complex data, such as unstructured mesh data.

Language：English   Publishing type：Research paper (scientific journal)  

It is important to develop a reliable and high-throughput simulation method for predicting airflows in the installation planning phase of windmill power plants. This study proposes a two-stage mesh generation approach to reduce the meshing cost and introduces a hybrid parallelization scheme for atmospheric fluid simulations. The meshing approach splits mesh generation into two stages: in the first stage, the meshing parameters that uniquely determine the mesh distribution are extracted, and in the second stage, a mesh system is generated in parallel via an in situ approach using the parameters obtained in the initialization phase of the simulation. The proposed two-stage approach is flexible since an arbitrary number of processes can be selected at run time. An efficient OpenMP-MPI hybrid parallelization scheme using a middleware that provides a framework of parallel codes based on the domain decomposition method is also developed. The preliminary results of the meshing and computing performance show excellent scalability in the strong scaling test.

DOI： 10.1155/2019/5231839

Language：English   Publishing type：Research paper (international conference proceedings)  

Due to the continuous increase in the scale of numerical simulations, research on visualization has shifted to in-situ/in-transit approaches. The interactivity of large-scale visualization has also become increasingly important. In order to observe large-scale visualization data in detail, high-resolution displays, such as those with 8K or 16K resolutions, give an opportunity to inspire new discovery. With the commoditization of high-resolution displays, tiled display walls (TDWs) have facilitated their use for the collaborative research, where a large screen size is required for sharing the content among multiple sites. In this paper, we propose a remote collaboration method that utilizes a TDW driver (ChOWDER), which enables content sharing among multiple sites even with different display configurations, and a visualization application (HIVE) for dynamic content sharing of interactive visualization results.

DOI： 10.1145/3231622.3232504

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Herein, we propose a web-based tiled display wall (TDW) system that is capable of supporting collaborative activities among multiple remote sites. Known as the Cooperative Workspace Driver (ChOWDER), this system introduces the virtual display area (VDA) concept as a method for handling various display configuration environments with different physical resolutions and aspect ratios. This concept, which is one of ChOWDER’s key features, allows ad hoc participation among multiple sites to facilitate remote collaboration and cooperative work.

DOI： 10.1007/978-3-030-00560-3_2

Language：English   Publishing type：Research paper (scientific journal)  

Currently, by default, integral curves are repeatedly re-computed in different flow visualization applications, such as FTLE field computation, source-destination queries, etc., leading to unnecessary resource cost. We present a compression-based data reuse framework for integral curves, to greatly reduce their retrieval cost, especially in a resource-limited environment. In our design, a hierarchical and hybrid compression scheme is proposed to balance three objectives, including high compression ratio, controllable error, and low decompression cost. Specifically, we use and combine digitized curve sparse representation, floating-point data compression, and octree space partitioning to adaptively achieve the objectives. Results have shown that our data reuse framework could acquire tens of times acceleration in the resource-limited environment compared to on-the-fly particle tracing, and keep controllable information loss. Moreover, our method could provide fast integral curve retrieval for more complex data, such as unstructured mesh data.

DOI： 10.1007/s12650-017-0428-4

Other Link： http://dx.doi.org/10.1007/s12650-017-0428-4

Language：English   Publishing type：Research paper (scientific journal)  

Ensemble computing, which is an instance of capacity computing, is an effective computing scenario for exascale parallel supercomputers. In ensemble computing, there are multiple linear systems associated with a common coefficient matrix. We improve the performance of iterative solvers for multiple vectors by solving them at the same time, that is, by solving for the product of the matrices. We implemented several iterative methods and compared their performance. The maximum performance on Sparc VIIIfx was 7.6 times higher than that of a naïve implementation. Finally, to deal with the different convergence processes of linear systems, we introduced a control method to eliminate the calculation of already converged vectors.

DOI： 10.1080/10618562.2016.1234046

Publisher：International Journal of Geoinformatics  

While the amount of data to be displayed on GIS continues to glow, WebGIS faces challenges in handling large datasets due to the heap memory limitations of web browsers. Meanwhile, the resolution of desktop displays is reaching its limit, making it challenging to display ultra-high-resolution content on the desktop, so using a Tiled Display Wall (TDW) offers a more feasible solution. In this context, we introduce ChOWDER, an open-source software that enables the distributed rendering of various contents, including 3DWebGIS on a TDW. It provides a detailed explanation of its distributed rendering functionality, utilizing iTowns, an open-source GIS platform, and Three.js, a JavaScript library for 3D graphics in a web browser using WebGL. As a practical example, using an ultra-high-resolution TDW system running ChOWDER, we will show how to display 3D WebGIS distributed rendering on a TDW with a horizontal resolution of 20K, composed of fifteen 4K displays and 15 PCs. Furthermore, we conducted experiments of distributed rendering of large-scale geographic information, including 3DTiles city building data on multiple displays, and confirmed that memory consumption was effectively distributed. ChOWDER is a middleware that can build ultra-high-resolution displays without special hardware. It can display not only 3DWebGIS distributed rendering but also various content simultaneously and in a bird's-eye view on ultra-high-resolution displays, making it applicable to applications such as wide-area GIS display and simultaneous display of a wide variety of data that cannot be overlaid on GIS.

DOI： 10.52939/ijg.v21i1.3785

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.imavis.2024.105056

Language：English   Publishing type：Research paper (international conference proceedings)  

Other Link： https://link.springer.com/chapter/10.1007/978-981-99-9470-0_23

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： https://doi.org/10.1145/3640900.3640903

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Proceedings - 2023 2023 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2023  

Rapid advances in high-throughput sequencers have made it possible to obtain large amounts of whole genome data quickly and inexpensively. As the amount of data increases, the increase in computation time has become a serious problem. One of the main causes of this problem is file I/O performance. Most pipelines do not implement file I/O suitable for distributed file systems, which are common storage systems in parallel computers used for large-scale analysis. In this study, we developed an I/O system adapted to distributed file systems. In the proposed system, storage access frequency was suppressed by I/O buffers, and thread parallelization by OpenMP was employed. We tested the developed system and a high parallel speedup was achieved. Availability: The developed system is freely available from https://github.com/SatoshiITO/GAPS

DOI： 10.1109/BIBM58861.2023.10385370

Scopus

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE Transactions on Visualization and Computer Graphics  

The objective of this work is to develop error-bounded lossy compression methods to preserve topological features in 2D and 3D vector fields. Specifically, we explore the preservation of critical points in piecewise linear and bilinear vector fields. We define the preservation of critical points as, without any false positive, false negative, or false type in the decompressed data, (1) keeping each critical point in its original cell and (2) retaining the type of each critical point (e.g., saddle and attracting node). The key to our method is to adapt a vertex-wise error bound for each grid point and to compress input data together with the error bound field using a modified lossy compressor. Our compression algorithm can be also embarrassingly parallelized for large data handling and in situ processing. We benchmark our method by comparing it with existing lossy compressors in terms of false positive/negative/type rates, compression ratio, and various vector field visualizations with several scientific applications.

DOI： 10.1109/TVCG.2022.3214821

Web of Science

Scopus

PubMed

Language：Japanese   Publisher：一般社団法人 日本風力エネルギー学会  

In the current project, the first author and the second author play a central role in conducting high-speed tuning and wind turbine wake analysis of the supercomputer version of RIAM-COMPACT. In this report, we applied the supercomputer version RIAM-COMPACT to the wind turbine wake simulation from the wind tunnel scale to the utility-scale wind turbine wakes. As a result, we clarified unsteady wake aerodynamics of wind turbines including multiple wake interactions with high precision and high reality.

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>A hemispheric-head cyclone separator has higher collection performance of fine particles comparing with a conventional cyclone separator with a cylindrical head. In order to optimize the shape model with hemispheric-head, we have investigated numerically and experimentally the air flow in various shape cyclone models for industrials. The purpose of this study is to develop a cyclone model for fuel cell vehicles based on the results for industrials. Since this model is installed in a fuel cell vehicle, it must be compact due to space constraints. Therefore, as the first stage of development, based on a model of a dome-shaped cyclone separator with a cyclone diameter of 54 mm, we numerically investigated the airflow in the model by changing the dust holder size and the inlet pipe connection height. The motion of fine particles was analyzed considering only drag and gravity, and the effect of internal airflow on collection performance was investigated. As a result, it is shown that the model with the low inlet pipe connection height and the small volume of the dust holder has the highest collection efficiency. It was found that even if the entry particles in the dust holder return to the conical separator part due to small dust holder, the air flow field of the highest collection efficiency model has high centrifugal separation performance by lowering the connection height of inlet pipe. It is also the most suitable in terms of space for installation in fuel cell vehicles.</p>

DOI： 10.1299/jsmefed.2022.os04-18

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmebiofro.2022.33.1d07

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

ChOWDER is an open-source, web-based scalable display system that consists of multiple display devices on which a web browser operates in cooperation to construct a single large pixel space. Newly introduced functionality of displaying 3D geographic information systems allows us to show large 3D geographic information on ultra-high-resolution tiled display system. This paper describes the method of implementation, use cases, and related works of this functionality.

Language：English   Publishing type：Research paper (other academic)  

The objective of this work is to develop error-bounded lossy compression methods to preserve topological features in 2D and 3D vector fields. Specifically, we explore the preservation of critical points in piecewise linear vector fields. We define the preservation of critical points as, without any false positive, false negative, or false type change in the decompressed data, (1) keeping each critical point in its original cell and (2) retaining the type of each critical point (e.g., saddle and attracting node). The key to our method is to adapt a vertex-wise error bound for each grid point and to compress input data together with the error bound field using a modified lossy compressor. Our compression algorithm can be also embarrassingly parallelized for large data handling and in situ processing. We benchmark our method by comparing it with existing lossy compressors in terms of false positive/negative/type rates, compression ratio, and various vector field visualizations with several scientific applications.

DOI： 10.1109/PacificVis48177.2020.6431

Language：English   Publishing type：Research paper (other academic)  

For web-browser-based scalable display systems, we recently presented the Virtual Display Area (VDA) [1] concept, which unifies different display resolutions and tiling by abstracting the physical pixel spaces into a single software display. Web browsers, however, are generally not designed for handling images of large size, even though ultra-high-resolution images emerge especially in the HPC and big data communities. We thus present an approach to handle ultra-high-resolution images for web-based scalable display systems while keeping the principle of the VDA to achieve both the efficiency of operations and the simplicity of software design. We show the advantage of our approach by comparing its performance to that of SAGE2, which is the de facto standard web-based scalable display system.

DOI： 10.1007/978-3-030-30949-7_13

Language：Japanese   Publishing type：Research paper (other academic)  

Voxel-based simulation of nasal airflow during a sniff

DOI： 10.1299/jsmebio.2019.31.1G22

Language：English   Publishing type：Research paper (scientific journal)  

This paper describes the simulation of airflow in human nasal airways using voxel-based modeling characterized by robust, automatic, and objective grid generation. Computed tomography scans of a healthy adult nose are used to reconstruct 3D virtual models of the nasal airways. Voxel-based simulations of restful inspiratory flow are then performed using various mesh sizes to determine the level of granularity required to adequately resolve the airflow. For meshes with close voxel spacings, the model successfully reconstructs the nasal structure and predicts the overall pressure drop through the nasal cavity.

DOI： 10.1080/10255842.2018.1555584

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (other academic)  

Estimating a form of equation that explains data is very useful to understand various physical, chemical, social, and biological phenomena. One effective approach for finding the form of an equation is to solve the symbolic regression problem using genetic programming (GP). However, this approach requires a long computation time because of the explosion of the number of combinations of candidate functions that are used as elements to construct equations. In the present paper, a novel method to effectively eliminate unnecessary functions from an initial set of functions using a deep neural network was proposed to reduce the number of computations of GP. Moreover, a method was proposed to improve the accuracy of the classification using eigenvalues when classifying whether functions are required for symbolic regression. Experiment results showed that the proposed method can successfully classify functions with over 90% of the data created in the present study.

DOI： 10.1007/978-3-030-30284-9_6

Language：Japanese   Publishing type：Research paper (scientific journal)  

Analyses and Visualization of Characteristics of Car Body Types by Using Convolutional Neural Network

DOI： 10.5057/jjske.TJSKE-D-18-00039

Language：English   Publishing type：Research paper (other academic)  

The computational performance of scientific applications on HPC systems is often much lower than user expectation based on the system's maximum performance specifications. To understand the basis for this performance gap, a multi-perspective evaluation is important. For instance, from the user perspective, correlating the theoretical computation coded as a source program with the actual computation workload produced by the compilers is valuable. From the system perspective, evaluating the characteristics of microarchitecture elements such as processor core and memory is of significance. An open source library called PMlib was developed to address these types of synthetic evaluations. PMlib provides an avenue for reporting the arithmetic/application workload explicitly coded in the source program, as well as the actually executed system workload. It also provides detailed utilization reports of processor-specific hardware including the categorized SIMD instruction statistics, the layered cache hit/miss rate, and the effective memory bandwidth, which are captured via hardware performance counters (HWPC). Using PMlib, users can conduct a synthetic analysis of application performance, and obtain useful feedback for further optimized execution of applications.

DOI： 10.1109/CANDARW.2018.00053

Language：English   Publishing type：Research paper (other academic)  

An increasing volume of data is produced by computational science applications executing on flagship-class supercomputers, such as the K computer. Most of these huge datasets would later pass through post-processing for visualization and analysis in order to derive meaningful information. Particular characteristics of the computing environment, application, and the dataset itself, can make efficiently exploring the performance capabilities of large-scale storage systems supporting these supercomputer a challenging task. This paper presents a characterization of the I/O and storage activity of jobs executed on the K computer focusing on post-processing purposes, based upon nine months of production operation recorded. Results demonstrate the intensive data demand of K computer applications, both in terms of volume of file I/O carried out during job execution, amount of data staged-in and staged-out, and number of files produced per job. These aspects shed light on challenges and opportunities for specialized data management libraries for posthoc data visualization and analysis.

DOI： 10.1109/ISCC.2018.8538488

Language：English   Publishing type：Research paper (other academic)  

Leading-edge supercomputer systems have been designed to achieve the highest computational performance possible for running a wide variety of large-scale simulations, and the pre-and post-processing are usually not considered in the main design feature. Although supercomputer systems may have peculiar CPU architecture, the auxiliary computational systems tend to use commodity based hardware and software in the form of servers and clusters. In the case of the K computer operational environment, at RIKEN R-CCS, the supercomputer itself is based on SPARC64 fx CPU architecture, and pre-and post-processing servers are based on traditional x86 CPU architecture. In this poster we present a large data visualization environment developed for this peculiar HPC operational environment, presenting some of the efforts made to meet the large data visualization needs. It is publicly known that the next-generation leading-edge Japanese supercomputer will abandon this CPU architecture in favor of another architecture, but we expect that some of the knowledge obtained in this development will also be useful for this future coming supercomputer system.

DOI： 10.1109/LDAV.2018.8739214

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Leading-edge HPC systems have already been generating a vast amount of time-varying complex data sets, and future-generation HPC systems are expected to produce much higher amounts of such data, thus making their visualization and analysis a much more challenging task. In such scenario, the In-situ visualization approach, where the same HPC system is used for both numerical simulation and visualization, is expected to become more a necessity than an option. On massively parallel environments, the Sort-last approach, which requires final image compositing, has become the de facto standard for parallel rendering. In this work, we present the 234Compositor, a scalable and flexible parallel image compositor framework for massively parallel rendering applications. It is composed of a single-stage power-of-two conversion mechanism based on 234 Scheduling of 3-2 and 2-1 Eliminations, and a final image gathering mechanism based on Data Padding and MPI Rank Reordering for enabling the use of MPI_Gather collective operation. In addition, the hybrid MPI/OpenMP parallelism can also be applied to take advantage of current multi-node, multi-core architecture of modern HPC systems. We confirmed the scalability of the proposed approach by evaluating a Binary-Swap implementation of 234Compositor on the K computer, a Japanese leading-edge supercomputer installed at RIKEN AICS. We also evaluated an integration with HIVE (Heterogeneously Integrated Visual-analytic Environment) in order to verify a real-world usage. From the encouraging scalability results, we expect that this approach can also be useful even on the next-generation HPC systems which may demand higher level of parallelism.

DOI： 10.1016/j.future.2017.02.011

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1142/S1793962318400068

Language：English   Publishing type：Research paper (scientific journal)  

Leading-edge supercomputers, such as the K computer, have generated a vast amount of simulation results, and most of these datasets were stored on the file system for the post-hoc analysis such as visualization. In this work, we first investigated the data generation trends of the K computer by analyzing some operational log data files. We verified a tendency of generating large amounts of distributed files as simulation outputs, and in most cases, the number of files has been proportional to the number of utilized computational nodes, that is, each computational node producing one or more files. Considering that the computational cost of visualization tasks is usually much smaller than that required for large-scale numerical simulations, a flexible data input/output (I/O) management mechanism becomes highly useful for the post-hoc visualization and analysis. In this work, we focused on the xDMlib data management library, and its flexible data I/O mechanism in order to enable flexible data loading of big computational climate simulation results. In the proposed approach, a pre-processing is executed on the target distributed files for generating a light-weight metadata necessary for the elaboration of the data assignment mapping used in the subsequent data loading process. We evaluated the proposed approach by using a 32-node visualization cluster, and the K computer. Besides the inevitable performance penalty associated with longer data loading time, when using smaller number of processes, there is a benefit for avoiding any data replication via copy, conversion, or extraction. In addition, users will be able to freely select any number of nodes, without caring about the number of distributed files, for the post-hoc visualization and analysis purposes.

DOI： 10.1142/S1793962318400068

Language：English   Publishing type：Research paper (scientific journal)  

To establish a new simplified approach to quantify the impact of surgical intervention on nasal airflow, we used voxel-based computational fluid dynamics simulations to analyze nasal airflow under unsteady flow conditions mimicking a sniff, which involves brief inhalation accompanied by rapid acceleration. The time-transient distribution of the flow rate in the coronal cross-section was investigated to validate the results of this voxel method against those of conventional boundary-fitted method. Despite a simple approach using coarse voxel grids, the voxel method accurately reproduced rapid changes in flow distribution during a sniff. We also found that correctly modeling rapid changes in the characteristic flow structure in a nasal cavity (including a jet posterior to the nasal valve and a recirculating flow in the upper anterior region of the cavity) is important for reproducing the unsteady flow distribution during a sniff. Thus, the voxel-based simulations can be used to assess the dynamics of unsteady nasal airflows.

DOI： 10.11239/jsmbe.56.37

Language：English   Publishing type：Research paper (other academic)  

This paper presents an in situ framework focused on time-varying simulations, and uses a novel temporal buffer for storing simulation results sampled at user-defined intervals. This framework has been designed to provide flexible data processing and visualization capabilities in modern HPC operational environments composed of powerful front-end systems, for pre-and post-processing purposes, along with traditional back-end HPC systems. The temporal buffer is implemented using the functionalities provided by Open Address Space (OpAS) library, which enables asynchronous one-sided communication from outside processes to any exposed memory region on the simulator side. This buffer can store time-varying simulation results, and can be processed via in situ approaches with different proximities. We present a prototype of our framework, and code integration process with a target simulation code. The proposed in situ framework utilizes separate files to describe the initialization and execution codes, which are in the form of Python scripts. This framework also enables the runtime modification of these Python-based files, thus providing greater flexibility to the users, not only for data processing, such as visualization and analysis, but also for the simulation steering.

DOI： 10.1007/978-3-030-02465-9_17

Language：English   Publishing type：Research paper (scientific journal)  

Abstract: Currently, by default, integral curves are repeatedly re-computed in different flow visualization applications, such as FTLE field computation, source-destination queries, etc., leading to unnecessary resource cost. We present a compression-based data reuse framework for integral curves, to greatly reduce their retrieval cost, especially in a resource-limited environment. In our design, a hierarchical and hybrid compression scheme is proposed to balance three objectives, including high compression ratio, controllable error, and low decompression cost. Specifically, we use and combine digitized curve sparse representation, floating-point data compression, and octree space partitioning to adaptively achieve the objectives. Results have shown that our data reuse framework could acquire tens of times acceleration in the resource-limited environment compared to on-the-fly particle tracing, and keep controllable information loss. Moreover, our method could provide fast integral curve retrieval for more complex data, such as unstructured mesh data.

DOI： 10.1007/s12650-017-0428-4

Language：Japanese   Publishing type：Research paper (scientific journal)  

Comparison and Visualization of Affective Information on Two Liquors' Reviews on the Web Using Data Mining

DOI： 10.5057/jjske.TJSKE-D-17-00052

Language：Japanese   Publishing type：Research paper (other academic)  

Performance Evaluation of Parareal Method for Large-Scale Spatio-Temporal Computation

Repository Public URL： http://hdl.handle.net/2324/1916268

Language：English   Publishing type：Research paper (international conference proceedings)  

he fiber surface generalizes the popular isosurface to multi-fields, visu- alizing the pre-images as surfaces. As with isosurfaces, however, fiber surface com- ponent may suffer from visual occlusion. The flexible isosurface avoids occlusion of components by tracking them topologically in the contour tree, at some cost to user comprehension. For the fiber surface, this requires computing the Reeb space, which poses further issues in comprehension. However, the flexible isosurface can also be defined as a set of user interactions, and we extend this notion to provide the flexible fiber surface, without pre-computing the global topology. Our on-demand tracking of surfaces is Reeb-free, as it does not require the explicit computation of the Reeb graph nor Reeb space. We study our geometrical approach taking into account how the semantics in the flexible isosurface generalizes to the Reeb-free multi-field analysis.

Other Link： http://eprints.whiterose.ac.uk/114659/

Language：English   Publishing type：Research paper (scientific journal)  

In the plan of products, affective information is increasingly utilized with diversification of a life style. Then, in this research, we had developed the system that visualizes the affective layered structures of liquors' reviews using rough set theory (hereafter, visualization system). Specifically, the development consists of the following steps. (1) The visualization system extracts affective words from the reviews of mail order sites. (2) We create the decision table in rough set theory using affective words. (3) We visualize the affective layered structure using the computed decision rules from decision table. We conducted the evaluation experiment of the visualization system for 20 subjects. We made ten subjects the summary of liquor reviews using the visualization system, and made the remaining ten subjects the summary of them without the visualization system. Consequently, the usefulness of the visualization system was verified from the contents and the time for creation of the summary.

DOI： 10.5057/jjske.TJSKE-D-16-00057

Language：Japanese   Publishing type：Research paper (scientific journal)  

In the plan of products, affective information is increasingly utilized with diversi cation of a life style. Then, in this research, we had developed the system that visualizes the affective layered structures of liquors’ reviews using rough set theory (hereafter, visualization system). Speci cally, the development consists of the following steps. (1) The visualization system extracts affective words from the reviews of mail order sites. (2) We create the decision table in rough set theory using affective words. (3) We visualize the affective layered structure using the computed decision rules from decision table. We conducted the evaluation experiment of the visualization system for 20 subjects. We made ten subjects the summary of liquor reviews using the visualization system, and made the remaining ten subjects the summary of them without the visualization system. Consequently, the usefulness of the visualization system was veri ed from the contents and the time for creation of the summary.

DOI： 10.5057/jjske.TJSKE-D-16-00057

Language：Japanese   Publishing type：Research paper (other academic)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Progress of Visualization Technology and its Contribution to Computational Science

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Large-Scale Parallel Visualization System HIVE

Language：Japanese   Publishing type：Research paper (scientific journal)  

HPC Enhanced Product Design

Language：Japanese   Publishing type：Research paper (scientific journal)  

Effectiveness of Two-dimensional Medical Image Interpolation in the Transverse Plane in the Voxel Analysis of Nasal Air Flow and Temperature

DOI： 10.11239/jsmbe.53.160

Language：English   Publishing type：Research paper (scientific journal)  

Large-scale numerical simulations on modern leading-edge supercomputers have been continuously generating tremendous amount of data. In-Situ Visualization is widely recognized as the most rational way for analysis and mining of such large data sets by the use of sort-last parallel visualization. However, sort-last method requires communication intensive final image composition and can suffer from scalability problem on massively parallel rendering and compositing environments. In this paper, we present the Multi-Step Image Composition approach to achieve scalability by minimizing undesirable performance degradation on such massively parallel rendering environments. We verified the effectiveness of this proposed approach on K computer, installed at RIKEN AICS, and achieved a speedup of 1.8× to 7.8× using 32,768 composition nodes and different image sizes. We foresee a great potential of this method to meet the even larger image composition demands brought about by the rapid increase in the number of processing elements on modern HPC systems.

DOI： 10.15748/jasse.2.108

Language：Japanese   Publishing type：Research paper (scientific journal)  

Performance improvement of iterative solver using bit-representation of sparse matrices(<Special Review>Selected Researches in CFD28)

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Grid Generation of Hierarchical Cartesian Data Structure for Large-Scale Thermal Flow Simulation over 10G Elements and Its Applications

Language：Japanese   Publishing type：Research paper (scientific journal)  

Voxel Simulation of Nasal Air Flow and Temperature Based on the Medical Images

DOI： 10.11239/jsmbe.52.33

Language：English   Publishing type：Research paper (scientific journal)  

It is difficult to carry out visualization of the large-scale time-varying data directly, even with the supercomputers. Data compression and ROI (Region of Interest) detection are often used to improve efficiency of the visualization of numerical data. It is well known that the Run Length encoding is a good technique to compress the data where the same sequence appeared repeatedly, such as an image with little change, or a set of smooth fluid data. Another advantage of Run Length encoding is that it can be applied to every dimension of data separately. Therefore, the Run Length method can be implemented easily as a parallel processing algorithm. We proposed two different Run Length based methods. When using the Run Length method to compress a data set, its size may increase after the compression if the data does not contain many repeated parts. We only apply the compression for the case that the data can be compressed effectively. By checking the compression ratio, we can detect ROI. The effectiveness and efficiency of the proposed methods are demonstrated through comparing with several existing compression methods using different sets of fluid data.

DOI： 10.1016/j.procs.2014.08.228

Language：English   Publishing type：Research paper (scientific journal)  

Supercomputer architectures are being upgraded using different level of parallelism to improve computing performance. This makes it difficult for scientists to develop high performance code in a short time. From the viewpoint of productivity and software life cycle, a concise yet effective infrastructure is required to achieve parallel processing. In this paper, we propose a usable building block framework to build parallel applications on large-scale Cartesian data structures. The proposed framework is designed such that each process in a simulation cycle can easily access the generated data files with usable functions. This framework enables us to describe parallel applications with fewer lines of source code, and hence, it contributes to the productivity of the software. Further, this framework was considered for improving performance, and it was confirmed that the developed flow simulator based on this framework demonstrated considerably excellent weak scaling performance on the K computer.

DOI： 10.1016/j.procs.2014.05.218

Language：Japanese   Publishing type：Research paper (scientific journal)  

2G15 Voxel-based simulation of heat transfer between nasal airflow and mucosal membrane

Language：Japanese   Publishing type：Research paper (scientific journal)  

Parallelization of a CFD system based on hierarchical Cartesian grids

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

3E14 Assessment of nasal surgery using voxel-based simulation

Language：English   Publishing type：Research paper (scientific journal)  

On hierarchical parallel environment with multicore processors, mapping of subdomains to CPU/cores were optimized considering both the communication speed of different communication paths and the communication pattern of a parallel application based on the domain decomposition method. We evaluated proposed method on massively paralleled Intel Xeon PC cluster and confirmed that it could reduce communication time and achieve higher parallel performance than without mapping in several benchmark tests.

DOI： 10.1016/j.compfluid.2012.04.024

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/SC.Companion.2012.371

Language：Japanese   Publishing type：Research paper (scientific journal)  

F302 Technology that joins product design and simulation

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of technology for very-large-scale voxel generation and its interface for simulators

Language：Japanese   Publishing type：Research paper (scientific journal)  

Advanced Visualization Technology on Large-Scale Numerical Simulation

DOI： 10.3154/jvs.32.125_2

Language：Japanese   Publishing type：Research paper (scientific journal)  

Selected Researches in CFD25

Language：Japanese   Publishing type：Research paper (scientific journal)  

7H16 Voxel-based thermo-fluid analysis of air conditioning function in the human nasal cavity

Language：Japanese   Publishing type：Research paper (scientific journal)  

402 Examination of parallel computing of a Lagrangian-Eulerian coupling method based on level sets

Language：Others   Publishing type：Research paper (scientific journal)  

A fluid solver using signed distance function (SDF) for shape representation was developed based on the immersed boundary method to simulate incompressible viscous flows. The forcing velocities near boundary are extrapolated by trilinear interpolation with taking into account a boundary condition using SDF. SMAC method is employed for solving basic equations for unsteady incompressible flows. The equations are discretized in space by 2nd-order central difference method, where the discretization near boundary is improved by SDF to satisfy a Dirichlet boundary condition for velocity. The fluid solver was verified in both steady and oscillating three-dimensional Poiseuille flows. As the grid spacing decreases, L² and L^∞ norm of the error of the axial velocity profile respectively decrease by the order of 1.96 and 1.89 for the oscillating flow. Therefore, the fluid solver enables to analyze the Poiseuille flow using Cartesian mesh by 2nd-order of accuracy in space.

DOI： 10.1299/kikaib.77.1813

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The objective of this research was to find the diffusion properties of vehicles on the road by using the V-Sphere Code. The diffusion coefficient and the size of the height of the wake were estimated with the LES option and the third order MUSCL scheme. We evaluated the code with the changes in the moments of Reynolds Stress along the mean streamline. The results show that at the leading part of a bluff body the LES has some advantages over the RNS since the changes in the strain rates are larger for the leading part. We estimated that the diffusion coefficient with the computed Reynolds stress (non-dimensional) was about 0.96 times the mean velocity.

Language：Japanese   Publishing type：Research paper (other academic)  

Thermo-fluid analysis of airflow in the human nasal cavity

DOI： 10.11368/nhts.2011.0.253.0

Language：Japanese   Publishing type：Research paper (scientific journal)  

9D-11 An Emphatic Rendering Method for Understanding Biomechanisms

Language：Japanese   Publishing type：Research paper (other academic)  

An Eulerian mesh-based scheme using adaptive mesh refinement for fluid-structure interaction

DOI： 10.11345/japannctam.59.0.52.0

Language：Japanese   Publishing type：Research paper (scientific journal)  

Automatically optimized core mapping for subdomains of domain decomposition methods on multicore parallel environment

Language：English   Publishing type：Research paper (scientific journal)  

High intensity focused ultrasound (HIFU) has been developed as a noninvasive therapeutic option. HIFU simulations are required to support the development of the HIFU device as well as the realization of noninvasive treatments. In this study, an HIFU simulator is developed that uses voxel data constructed from computed tomography scan data on the living human body and signed distance function (SDF) data to represent the object. The HIFU simulator solves the conservation equations of mass and momentum for mixtures with the equation of state for each medium. The numerical method is the finite-difference time-domain method. A high-order finite-difference method based on Lagrange interpolation is implemented to reduce numerical phase error. This approach reproduces wave propagation to an nth order of accuracy. Representation of the sound source by volume fraction, which is obtained from the SDF using a smoothed Heaviside function, provides around 1.66th order of accuracy in the spherical wave problem. As a realistic application, transcranial HIFU therapy for a brain tumor is modeled, where tissue inhomogeneity causes not only displacement of the focal point but also diffusion of the focused ultrasound. Even in such cases, focus control using phase delays, which are pre-computed based on the time-reversal procedure, enables correct focal point targeting as well as improved ultrasound focusing.

DOI： 10.1002/fld.2470

Language：Japanese   Publishing type：Research paper (scientific journal)  

Current State of CFD Technology and Trend in the Future

Language：Japanese   Publishing type：Research paper (scientific journal)  

9D-14 Voxel-based simulation of air flow and temperature in the nasal cavity

Language：English   Publishing type：Research paper (scientific journal)  

The development of high-intensity focused ultrasound (HIFU) therapy for deeply situated cancer has been desired. One problem is focal point displacement due to the inhomogeneity of the human body. The objectives are the realization of appropriate phase control of an array transducer and support for preoperative planning of HIFU therapy by the computational prediction of ablation regions. To these ends, in this study we have developed an HIFU simulator that employs a voxel phantom constructed from CT/MRI data of a living human body. To reproduce the pressure propagation through an inhomogeneous medium, the mass and momentum equations for a mixture with the equation of state of the medium are solved. The ablation of tissue is modeled as a phase transition by using the phase field model. Then, the heat equation with viscous dissipation as a heat source and the Allen-Cahn equation with a free energy model are solved to predict the development of the ablation region. The basic equations are discretized by the finite difference method. HIFU therapy with an array transducer for liver cancer is reproduced numerically. Although the results without phase control show displacement and diffusion of the focal point due to the inhomogeneity of the human body, a clear focal point is obtained by using the array transducer with an appropriate phase delay obtained from pre-computation. The HIFU simulator predicts that the ablation region will develop close to the target, owing to the phase control of the array transducer.

DOI： 10.1002/fld.2467

Language：Japanese   Publishing type：Research paper (scientific journal)  

Are Supercomputers Really Useful for Engineering?

Language：Japanese   Publishing type：Research paper (scientific journal)  

Simulation of Incompressible Viscous Flow on Cartesian Grid for Arbitrary Geometries Composed of Non-Watertight Polygon Elements(Fluids Engineering)

DOI： 10.1299/kikaib.76.764_536

Language：Japanese   Publishing type：Research paper (scientific journal)  

Robust voxelization algorithm with memory-efficient data structure

Language：Japanese   Publishing type：Research paper (other academic)  

Voxel Simulation of Airflow in Human Nasal Cavity

DOI： 10.11368/nhts.2010.0.89.0

Language：Japanese   Publishing type：Research paper (scientific journal)  

APPLICATION OF A PARTITIONED COUPLING ALGORITHM USING LEVEL SET FUNCTION TO FOLDED AIRBAG DEPLOYMENT

Language：English   Publishing type：Research paper (scientific journal)  

A useful computational method was proposed for an incompressible viscous flow simulation around arbitrary geometries on a Cartesian grid system. This method has a remarkable feature that allows us to simulate the flow around geometries which are composed of non-watertight and incomplete polygon elements without any repair. The proposed method can reduce manpower drastically in the process of the mesh generation because the repair of the defective polygon elements can be eliminated. In this method, governing equations are discretized using the extrapolated velocity to satisfy the no-slip condition on the wall surface taking into account the distance between the polygons and the cell center on the Cartesian grid. Moreover, this approach has a higher accuracy of shape approximation compared with the voxel method. In this paper, four different cases were calculated to validate the proposed method. Firstly, the flow around an inclined plate thinner than the mesh size was calculated to show that this method can simulate the flow around the nonwatertight geometry. Additionally, in this case, the accuracy of shape approximation was compared between the proposed method and the voxel method. Sencondly and thirdly, flows around a circular cylinder (/?e=40, 100) were calculated to confirm the accuracy of solutions in the steady and unsteady flows. Finally, an internal flow in a curved duct was calculated to compare the solutions with other researcher's results including the experiment. Consequently, it was found that the proposed method could simulate the flow around the non-watertight geometry and this method had the reasonably good accuracy compared with the literature.

Language：Japanese   Publishing type：Research paper (scientific journal)  

0415 Voxel simulation of nasal airflow

Language：English   Publishing type：Research paper (scientific journal)  

We show that a fluid-structure coupling method based on a fixed Eulerian mesh using the level set function is applicable to fluid-structure interaction (FSI) problems involving incompressible viscous fluids and thin elastic structures. The coupling method was originally proposed for large-deformation FSI analyses of high-speed compressible inviscid flows and thin structures such as airbags. We introduce a novel interface-treatment technique that uses virtual particles with level sets and structural normal velocities to enforce the kinematical condition at the fluid-structure interface on a fluid fixed mesh. The virtual particles also have structural tangent velocities so as to impose no-slip conditions at the interface. Application of the method to finite-deformation FSI problems, and comparison of the results with those obtained by the conventional moving ALE mesh-based scheme show the adequacy of the method. It is confirmed that the appearance of the flow and geometry of the interface are similar to those for the ALE scheme.

DOI： 10.11345/nctam.58.325

Language：English   Publishing type：Research paper (scientific journal)  

The development of the HIFU therapy for the deeply placed cancer such as the liver cancer and brain cancer has been desired. One problem is the displacement of the focal point due to the reflection and refraction of ultrasound. In the present study, the HIFU therapy for the brain cancer through a skull with a bowl-shape array transducer is performed numerically. Our approach is to solve the mass and momentum equations for mixture with the equation of state of media. The nonlinearity is mainly taken into account through the equation of state of the media. The three-dimensional controllability of the focal point by the array transducer with a phase delay is examined. As the result of the ultrasound propagation through the skull with the phase delay, we obtain a clear focal point where the peak pressure is higher than that without the phase delay. Therefore, the array transducer with the appropriate phase delay enables to assign the focal point to the target adequately, even if the ultrasound propagates through the inhomogeneous medium as a human skull.

DOI： 10.1016/j.phpro.2010.01.042

Language：Japanese   Publishing type：Research paper (scientific journal)  

503 Development of parallel FEM application using SPHERE

Language：Japanese   Publishing type：Research paper (scientific journal)  

Visualization for Extreme Large Data Set Toward a Next-Generation Super Computer

Language：Japanese   Publishing type：Research paper (scientific journal)  

515 Airbag deployment simulation including the effect of outside air

Language：Japanese   Publishing type：Research paper (scientific journal)  

S0203-1-2 Numerical simulation of nasal airflow

Language：Japanese   Publishing type：Research paper (scientific journal)  

J0102-3-3 Simulation of the high intensity focused ultrasound therapy including the heat coagulation of tissue

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of an application middleware for the next-generation supercomputer

Language：Japanese   Publishing type：Research paper (scientific journal)  

S202 Progress of volume-based CFD system

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Interface treatment with no-slip condition using level set virtual particles for fluid-structure interaction

DOI： 10.11345/japannctam.58.0.197.0

Language：Japanese   Publishing type：Research paper (scientific journal)  

Seamless Environment of Fluid Simulation with Volume Data

DOI： 10.11345/japannctam.58.0.12.0

Language：English   Publishing type：Research paper (scientific journal)  

As computational fluid dynamics plays a crucial role in vehicle body design, the CFD committee, one of the technical committees comprising JSAE, embarked on a benchmark project in which a number of CFD codes would be tested on the same vehicle body. A wind tunnel test of the 1/5 scale model was conducted to provide reference data for the benchmark test. In this paper, details of the measurements are presented. On the body surface, smooth flow patterns were visualised by tufting. It was also found that total pressure loss in the wake of the model displayed a unique pattern similar to a mushroom cloud.

DOI： 10.11351/jsaereview.30.51

Language：English   Publishing type：Research paper (scientific journal)  

This paper presents a performance evaluation of large-scale parallel image compositing on a T2K Open Supercomputer. Traditional image compositing algorithms were not primarily designed for exploiting the combined message passing and the shared address space parallelism provided by systems such as T2K Open Supercomputer. In this study, we investigate the Binary-Swap image compositing method because of its promising potential for scalability. We propose some improvements to the Binary-Swap method aiming to fully exploit the hybrid programming model. We obtained encouraging results from the performance evaluation conducted on Todai Combined Cluster, a T2K Open Supercomputer at the University of Tokyo. The proposed improvements have also shown a high potential to tackle the large-scale image compositing problem on leading-edge HPC systems where an ever increasing number of processing cores is involved.

DOI： 10.2197/ipsjtrans.2.140

Language：English   Publishing type：Research paper (scientific journal)  

This paper presents a performance evaluation of large-scale parallel image compositing on a T2K Open Supercomputer. Traditional image compositing algorithms were not primarily designed for exploiting the combined message passing and the shared address space parallelism provided by systems such as T2K Open Supercomputer. In this study, we investigate the Binary-Swap image compositing method because of its promising potential for scalability. We propose some improvements to the Binary-Swap method aiming to fully exploit the hybrid programming model. We obtained encouraging results from the performance evaluation conducted on Todai Combined Cluster, a T2K Open Supercomputer at the University of Tokyo. The proposed improvements have also shown a high potential to tackle the large-scale image compositing problem on leading-edge HPC systems where an ever increasing number of processing cores is involved.

DOI： 10.11185/imt.4.780

Language：Japanese   Publishing type：Research paper (scientific journal)  

842 Airbag Deployment Simulation using Level Set Function

Language：Japanese   Publishing type：Research paper (scientific journal)  

F1-9 Development of a middleware for life science simulation

Language：Japanese   Publishing type：Research paper (scientific journal)  

F1-7 Numerical Simulation for the Less Invasive Therapy using High Intensity Focused Ultrasound

Language：Japanese   Publishing type：Research paper (scientific journal)  

F1-3 Environment of software development and visualization for life science

Language：Japanese   Publishing type：Research paper (scientific journal)  

Three Dimensional Flow around a Cylindrical Object on pFTT Mesh with Adaptive Refinement

Language：Japanese   Publishing type：Research paper (scientific journal)  

Investigation of Incompressible Flow Calculation for Thin Objects on Cartesian Grid

Language：Japanese   Publishing type：Research paper (scientific journal)  

ROI Detection and Flow Visualization Based on Gaze Information

Language：Japanese   Publishing type：Research paper (scientific journal)  

Coupled analysis of high-speed flow and large-deformable shell using level set function

Language：Japanese   Publishing type：Research paper (scientific journal)  

NUMERICAL SIMULATION FOR THE ASSISTANCE OF HIGH INTENSITY FOCUSED ULTRASOUND THERAPY

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Advanced Simulation System for Thermal Fluid/Structure Interaction Problem and Its Automotive Application

Language：Japanese   Publishing type：Research paper (scientific journal)  

OUT OF CORE IMPLEMENTATION OF LINE DRAWINGS FOR LARGE SCALE VOLUME DATA

Language：Japanese   Publishing type：Research paper (scientific journal)  

Level set particle interface treatment for large deformation FSI analyses

DOI： 10.11345/japannctam.57.0.286.0

Language：Japanese   Publishing type：Research paper (scientific journal)  

G1305 Investigation into Interface Treatment in Fluid-Structure Coupling Method with Level Set Function(2)

Language：Japanese   Publishing type：Research paper (scientific journal)  

G1305 Investigation into Interface Treatment in Fluid-Structure Coupling Method with Level Set Function(1)

Language：Japanese   Publishing type：Research paper (scientific journal)  

Identification of ROI in 3D Flow Field Using Eye Tracking Data and Automatic Streamline Placement

Language：Japanese   Publishing type：Research paper (scientific journal)  

AMR simulation with pFTT data structure

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Object-oriented Parallel Class Library and Performance Evaluation of Benchmark Code

Language：Japanese   Publishing type：Research paper (scientific journal)  

4101 Development of the application for the design of medical ultrasound transducers

Language：Japanese   Publishing type：Research paper (scientific journal)  

1106 Fluid-Structure Coupled Analysis using Partitioned Solution Method with Level Set Function

Language：Japanese   Publishing type：Research paper (scientific journal)  

2125 A Study of AMR simulation with pFTT Data Structures

Language：Japanese   Publishing type：Research paper (scientific journal)  

3638 Simulation of Temperature Rise during High Intensity Focused Ultrasound Therapy

Language：Japanese   Publishing type：Research paper (scientific journal)  

2218 An Implementation of Boundary Condition of Incompressible Flow Solver on Voxel Method

Language：Japanese   Publishing type：Research paper (scientific journal)  

Progressive Visualization System and Its Utilization

DOI： 10.3154/jvs.26.Supplement1_39

Language：Japanese   Publishing type：Research paper (scientific journal)  

SPHERE

Language：Japanese   Publishing type：Research paper (scientific journal)  

125 Numerical Analysis for Aerodynamic Sound using Limited Compressible Formulation

Language：Japanese   Publishing type：Research paper (scientific journal)  

SPHERE : : A Framework for Development of Physical Simulation

Language：Japanese   Publishing type：Research paper (scientific journal)  

606 SPHERE

Language：Japanese   Publishing type：Research paper (scientific journal)  

F04-(2) Construction of Problem Solving Environment assisted by Visual Data Mining Technology

Language：Japanese   Publishing type：Research paper (scientific journal)  

629 A Study of Simulation Using Octree with Different Data Structures

Language：Japanese   Publishing type：Research paper (scientific journal)  

A Novel Platform for Next-Generation Visualization System

Language：Japanese   Publishing type：Research paper (scientific journal)  

Gaze-Directed Flow Visualization System

DOI： 10.3154/jvs.25.Supplement1_255

Language：Japanese   Publishing type：Research paper (scientific journal)  

Design and Development of Multi-Platform Visualization API

DOI： 10.3154/jvs.25.Supplement2_365

Language：Japanese   Publishing type：Research paper (scientific journal)  

SPHERE

Language：Japanese   Publishing type：Research paper (scientific journal)  

A Novel Platform for Next-Generation Visualization System

DOI： 10.3154/jvs.25.Supplement1_249

Language：Japanese   Publishing type：Research paper (scientific journal)  

Potential of CFD System Based on Volume Data(<Special Feature>Computer Aided Design and Production System Based on Voxel or Volume Data Structure)

Language：Japanese   Publishing type：Research paper (scientific journal)  

Simulation of ultrasound propagation in body

Language：Japanese   Publishing type：Research paper (scientific journal)  

Performance evaluation of interactive volume rendering with a hardware compositor

Language：Japanese   Publishing type：Research paper (scientific journal)  

High Performance Visualization on PC Cluster with Image Merge Unit

DOI： 10.3154/jvs.24.Supplement1_299

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Interactive Visualization System for Unsteady Large-Scale Data Set

Language：Japanese   Publishing type：Research paper (scientific journal)  

Experiences that Got Stuck in the Deep of CFD

DOI： 10.11458/tsj.32.263

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Interactive Visualization System for Unsteady Large-Scale Data Set

DOI： 10.3154/jvs.24.Supplement1_311

Language：English   Publishing type：Research paper (other academic)  

This paper describes the design and performance of an interactive visualization system developed specifically for improved understanding of time-varying volume data from thermal flow simulations for vehicle cabin and ventilation design. The system uses compression to allows for better memory utilization and faster data transfer, hardware accelerated rendering to enable interactive exploration, and an intuitive user interface to support comparative visualization. In particular, the interactive exploration capability offered by the system raises scientists to a new level of insight and comprehension. Compared to a previous visualization solution, such a system helps scientists more quickly identify and correct design problems.

DOI： 10.1145/827051.827072

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Interactive Volume Rendering System for Product Design

Language：Japanese   Publishing type：Research paper (scientific journal)  

A Robust Fluid Simulation System to support Product Design

Language：Japanese   Publishing type：Research paper (scientific journal)  

Research Trend of Numerical Prediction of Aerodynamic Sound in Automobile Design

DOI： 10.11372/souonseigyo1977.27.318

Language：Japanese   Publishing type：Research paper (scientific journal)  

An Implementation of Boundary Condition to Poisson Equation for Complex Geometories on Voxel Method

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.11426/nagare1982.21.16

Language：Japanese   Publishing type：Research paper (scientific journal)  

Product Design using Cartesian Mesh Method(<Special Review>CFD toward Practical Applications)

Language：Japanese   Publishing type：Research paper (scientific journal)  

Robust approach of CFD for automotive applications

Language：Japanese   Publishing type：Research paper (scientific journal)  

Development of Predicting Technology for Prevention of Snow Intrusion into Air Cleaner

Language：Japanese   Publishing type：Research paper (scientific journal)  

Numerical Analysis of Automotive Wind Noise

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

This paper describes the prediction of radiated wind noise from automobiles and its reduction. The Lighthill acoustic analogy was employed to estimate the wind noise at far field. In order to compute accurate pressure fluctuations, which play a role as the noise sources in the analogy, an overlapped grid system is used to calculate flow fields in detail with a finite-difference method. This approach was applied to predict the wind noise radiated from a door mirror and a front pillar. Measured data are compared with the computed results of pressure fluctuations on the side-window surface. The predicted pressure fluctuations agree well with the experimental results. Then, shapes of the front pillar and the door mirror were modified based on the computed results so as to reduce the wind noise. The effects of the modification were proved by additional experiments.

Language：English  

The purpose of this study is to construct a practical flow simulation system and to investigate the feasibility of this system for actual vehicle development process. In order to get the solution quickly, well-established Cartesian solver is employed with a volume mesh (voxel) system, which has a great advantage of short modeling time and robustness for a complex geometry. In addition, incorporated hhierarchical nested mesh structure leads high-resolution results without the increase of computing time. Computed results were demonstrated for underhood flows, flows passing through the front grilles and an air-conditioner duct flow. The all computed results showed good agreement with the experimented flow fields and enough short turnaround time. As a consequence, the present approach to simulate the flow around the complex shape is very efficient, powerful and has enough accuracy to support the vehicle development process.

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Synthesis of Aerodynamic Noise Emitted from a Door Mirror and Visualization of Flows around it Using CFD

Language：Japanese   Publishing type：Research paper (scientific journal)  

3-D Unsteady Incompressible Flow Analysis Using Multi-level Cartesian Grid System

Language：Japanese   Publishing type：Research paper (scientific journal)  

A CFD STUDY OF CHANGES IN FLOW CAUSED BY SMALL MODIFICATION IN A-PILLAR SHAPE OF A PASSENGER CAR

Language：Japanese   Publishing type：Research paper (scientific journal)  

Synthesis of Aerodynamic Noise Emitted from a Door Mirror and Visualization of Flows around it Using CFD

DOI： 10.3154/jvs.16.1Supplement_87

Language：English   Publishing type：Research paper (scientific journal)  

The aerodynamic noise caused by an outside door mirror of a passenger car was calculated and synthesized. Flows around the car including the mirror were computed using a finite-difference method and an overlapping grid technique. Sound pressure of the aerodynamic noise in far field from the car was computed with Curie's formula using unsteady pressure distribution on the mirror which is numerically solved from the incompressible Navier-Stokes equations. The sound is then synthesized for engineers to evaluate. We investigate the relation between noise sources and the flow field, and find that the strong noise sources are distributed along sepalation lines. This means it possible to reduce the noise if we can avoid separation or fix sepalation lines. Considering it, we modified the mirror shape and succeeded to reduce the aerodynamic noise.

Language：Japanese   Publishing type：Research paper (scientific journal)  

Flow around Two Square Cylinders in Staggered Arrangements.

DOI： 10.2322/jjsass1969.40.276

Language：Japanese   Publishing type：Research paper (scientific journal)  

Investigation of Automotive Radiator Using 3-Dimensional Analysis

DOI： 10.3154/jvs.11.Supplement2_135

Event date： 2024.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Kobe   Country：Japan  

Event date： 2024.9

Language：English   Presentation type：Poster presentation  

Venue：Kobe   Country：Japan  

Event date： 2024.9

Language：English   Presentation type：Poster presentation  

Venue：Yonezawa, Yamagata   Country：Japan  

Event date： 2024.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, British Columbia   Country：Canada  

Event date： 2024.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, British Columbia   Country：Canada  

Event date： 2024.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, British Columbia   Country：Canada  

Event date： 2024.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸市   Country：Japan  

Event date： 2024.4

Language：English  

Venue：Nagoya   Country：Japan  

Other Link： https://sighpc.ipsj.or.jp/HPCAsia2024/posters.html

Event date： 2024.3

Language：English   Presentation type：Oral presentation (general)  

Venue：National Center for High-Performance Computing in Hsinchu Science Park   Country：Taiwan, Province of China  

Other Link： https://sites.google.com/site/atathpsc/

Event date： 2024.3

Language：English   Presentation type：Oral presentation (general)  

Venue：National Center for High-Performance Computing in Hsinchu Science Park   Country：Taiwan, Province of China  

Other Link： https://sites.google.com/site/atathpsc/

Event date： 2024.2 - 2024.4

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学　稲森財団記念館   Country：Japan  

Event date： 2023.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：那覇   Country：Japan  

Event date： 2023.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福井県県民ホール, 福井   Country：Japan  

Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：ミューザ川崎   Country：Japan  

Event date： 2023.11

Language：English  

Venue：Singapore   Country：Singapore  

Other Link： https://www.iscb.org/iscb-news-items/5157-november-10-2023-giw-iscb-asia-2023-announcing-the-conference-programme

Event date： 2023.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：ルートイングランティア太宰府, 福岡   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：香川大学 幸町キャンパス   Country：Japan  

Event date： 2023.5

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Hamburg   Country：Germany  

Other Link： https://www.isc-hpc.com/project-posters-2023.html

Event date： 2023.4 - 2024.4

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学筑紫キャンパス   Country：Japan  

Event date： 2023.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Online, NCU Center for Mathematics and Theoretical Physics, National Central University, TW   Country：Japan  

Other Link： https://sites.google.com/site/atathpsc/

Event date： 2023.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Online, NCU Center for Mathematics and Theoretical Physics, National Central University, TW   Country：Japan  

Other Link： https://sites.google.com/site/atathpsc/

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台国際センター   Country：Japan  

Event date： 2022.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：札幌   Country：Japan  

Event date： 2022.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Xining   Country：China  

In the scientific visualization and data analysis workflow, data transmission bandwidth and memory resources have become the main bottlenecks when handling large-scale volume data. As a direct and effective scheme, data reduction is generally used to decrease data movement overhead and memory usage. However, it is still a challenge to obtain visualization results from reduced data without losing too many features. This paper proposes a visualization scheme for large-scale volume data based on enhanced super-resolution generative adversarial networks (ESRGAN) and designs a reduction-restoration workflow. Firstly, in order to reduce memory footprint, we propose an error-controlled data reduction method to delete data in 3D space, which is based on octree. Secondly, rendered images with loss of details are generated by performing volume rendering on reduced data. Lastly, to obtain feature-lossless visualization results, we apply ESRGAN to restore the details of rendered images. Based on the above scheme, the dual goals of data reduction and visual feature retention can be realized. Finally, the effectiveness of the proposed method is demonstrated by evaluating the performance of data reduction and visual restoration.

Other Link： https://chinavis.org/2022/paper.html

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Japan  

Event date： 2021.4

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

シミュレーションは与えられた支配方程式と初期条件・境界条件に基づいて時間積分し、現象の時間発展を追う。しかし、その支配方程式の形式が不明な現象も少なからずあり、方程式の形を知ることは現象理解に重要である。この講演では、遺伝的プログラミングを用いてデータから方程式を探索する方法とその可能性について紹介する。

Event date： 2021.1

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Online   Country：Japan  

ChOWDER is an open-source, web-based scalable display system that consists of multiple display devices on which a web browser operates in cooperation to construct a single large pixel space. Newly introduced functionality of displaying 3D geographic information systems allows us to show large 3D geographic information on ultra-high-resolution tiled display system. This paper describes the method of implementation, use cases, and related works of this functionality.

Event date： 2020.4

Language：English  

Venue：Tianjin   Country：China  

The objective of this work is to develop error-bounded lossy compression methods to preserve topological features in 2D and 3D vector fields. Specifically, we explore the preservation of critical points in piecewise linear vector fields. We define the preservation of critical points as, without any false positive, false negative, or false type change in the decompressed data, (1) keeping each critical point in its original cell and (2) retaining the type of each critical point (e.g., saddle and attracting node). The key to our method is to adapt a vertex-wise error bound for each grid point and to compress input data together with the error bound field using a modified lossy compressor. Our compression algorithm can be also embarrassingly parallelized for large data handling and in situ processing. We benchmark our method by comparing it with existing lossy compressors in terms of false positive/negative/type rates, compression ratio, and various vector field visualizations with several scientific applications.

Event date： 2020.1

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Event date： 2020.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Tainan   Country：Taiwan, Province of China  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Sendai   Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Kawagoe   Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Event date： 2019.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Gdansk   Country：Poland  

Event date： 2019.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Saitama   Country：Japan  

Event date： 2019.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Bielefeld   Country：Germany  

Event date： 2018.12

Language：Japanese  

Venue：Tokyo   Country：Japan  

PMlib that provides a function of thread performance monitoring

Event date： 2018.12

Language：Japanese  

Venue：Tokyo   Country：Japan  

Convergence of Parallel-in-time Integration for advection equation by Parareal Method

Event date： 2018.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Dallas   Country：United States  

Event date： 2018.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Berlin   Country：Germany  

Event date： 2018.10

Language：English  

Venue：Tainan   Country：Taiwan, Province of China  

Event date： 2018.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Frankfurt   Country：Germany  

Event date： 2018.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Event date： 2018.5

Language：English  

Venue：Roscoff   Country：France  

Event date： 2018.3

Language：English  

Venue：Tokyo   Country：Japan  

Repository Public URL： http://hdl.handle.net/2324/1916269

Event date： 2018.2

Language：English   Presentation type：Oral presentation (general)  

Venue：Tainan   Country：Taiwan, Province of China  

Event date： 2018.2

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

Event date： 2018.1

Language：English  

Venue：Tokyo   Country：Japan  

In this paper, we present a study on the available open-source software (OSS) for large-scale data visualization on the SPARC64fx based HPC systems, such as the K computer and also the Fujitsu PRIMEHPC FX family of supercomputers (FX10 and FX100), which are commonly available throughout Japan. It is widely known that these HPC systems have been generating a vast amount of simulation results in a wide range of science and engineering fields. However, there was no much information regarding the large-scale data visualization software and approaches in such HPC infrastructure. In this work, we focused on the visualization approaches where the HPC hardware resources are directly used for the visualization processing, which can be helpful to minimize the large data transfer issue for the visualization and analysis purposes. This study includes both OpenGL (Open Graphics Library) and nonOpenGL based visualization approaches, and also the availability of the GLSL (OpenGL Shading Language) handling functionalities. Although it is a short survey focusing only on the post-processing issue, we expect that this study can be useful and helpful for the current and future potential users of the SPARC64fx CPU based HPC systems, which are still in active use throughout Japan.

Event date： 2018.1

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 2017.12

Language：Japanese  

Venue：Hiroshima   Country：Japan  

Event date： 2017.12

Language：Japanese  

Venue：Kyoto   Country：Japan  

Repository Public URL： http://hdl.handle.net/2324/1916254

Event date： 2017.12

Language：Japanese  

Venue：Kyoto   Country：Japan  

Event date： 2017.11 - 2017.12

Language：English  

Venue：Banff   Country：Canada  

Event date： 2017.11

Language：English  

Venue：Bangkok   Country：Thailand  

Extremeweather events, such as unexpected and sudden torrential rains, have received increasing attention by the specialists as well as ordinary people due to the possibility of causing severe material damages and human losses. Computational climate scientists have been working on high-resolution time-varying, multivariate numerical simulations of this kind of short-term event, which is still hard to predict. Local governments of the natural disaster prone countries, like Japan, usually possess disaster management sectors, responsible for storing the disaster related data and analysis results. In this paper, we present a visualization framework for enabling the interactive exploration of the causality, such as of the disasters and the related extreme weather events. The end users will be able to identify the spatio-temporal regions where there is a strong strength of cause-effect relationships. As a case study, we studied the unexpected torrential rain occurred in the city of Kobe, in 2008, where a flash flood, in the urban area, caused some human losses. We utilized high-resolution computational climate simulation results executed on a supercomputer, and the measured river level data obtained from the Civil Engineering Office of Kobe City. We expected that this kind of tool can assist the specialists for better understanding the cause-effect relationships between the extreme weather and the related disasters, as well as, the local government policy makers in the adaptation policies for the disaster risk reductions.

Event date： 2017.10

Language：English  

Venue：Ascona   Country：Switzerland  

Event date： 2017.10

Language：English  

Country：Brazil  

Event date： 2017.7

Language：English  

Venue：Genoa   Country：Italy  

In this paper, we present a distributed data visualization framework for HPC environments based on the PBVR (Particle Based Volume Rendering) method. The PBVR method is a kind of point-based rendering approach where the volumetric data to be visualized is represented as a set of small and opaque particles. This method has the object-space and image-space variants, defined by the place (object or image- space) where the particle data sets are generated. We focused on the object-space approach, which has the advantage when handling large-scale simulation data sets such as those generated by modern HPC systems. In the object-space approach, the particle generation and the subsequent rendering processes can be easily decoupled. In this work, we took advantage of this separability to implement the proposed distributed rendering framework. The particle generation process utilizes the functionalities provided by the KVS (Kyoto Visualization System), and the particle rendering process utilizes the functionalities provided by the HIVE (Heterogeneously Integrated Visual- analytics Environment). The proposed distributed visualization framework is targeted to work also on systems without any hardware graphics acceleration capability, which are commonly found on modern HPC operational environments. We evaluated this PBVR-based distributed visualization infrastructure on the K computer operational environment by utilizing a CPU-only processing server for the particle data generation and rendering. In this preliminary evaluation, using some CFD (Computational Fluid Dynamics) simulation data sets, we obtained encouraging results for pushing further the development in order to make this system available as an effective visualization alternative for the HPC users.

Event date： 2017.5

Language：English  

Venue：Okinawa   Country：Japan  

Event date： 2017.3

Language：Japanese  

Venue：Tokyo   Country：Japan  

Event date： 2017.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2017.3

Language：Japanese  

Venue：Saga   Country：Japan  

Event date： 2017.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2017.2

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Event date： 2017.2

Language：English  

Venue：Tokyo   Country：Japan  

Event date： 2017.2

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：神戸   Country：Japan  

Event date： 2017.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：土岐   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：沖縄   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：Naha   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：Kyoto   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：Tokyo   Country：Japan  

Event date： 2016.12

Language：Japanese  

Venue：Tokyo   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋   Country：Japan  

Event date： 2016.11 - 2016.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Banff   Country：Canada  

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Salt Lake   Country：United States  

Event date： 2016.11

Language：English  

Venue：SaltLake   Country：United States  

Event date： 2016.11

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：大阪   Country：Japan  

Event date： 2016.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

Event date： 2016.10

Language：English  

Venue：Kyoto   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：品川、東京   Country：Japan  

Event date： 2016.9 - 2017.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Honolulu   Country：United States  

erimentally and numerically the characteristics of gas flow (single phase flow) in the hemispheric head cyclone separator without flowing particles and to find the flow characteristics contributing into high collection efficiency. It is shown that the numerical results calculated by RIKEN’s computational code and K computer are qualitatively agreement with the experimental results. The numerical results at Re = 2.3  105 show the characteristics of the outer spiraling flow, the vortex rope formed at the central core, the longitudinal vortices surrounded the vortex rope, in the hemispherical head cyclone separator, comparing with a conventional flat head cyclone separator. Additionally it is found that the total energy loss in the spherical head is smaller than that in the flat head.

Event date： 2016.9

Language：English  

Venue：Honolulu   Country：Other  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2016.9

Language：Japanese  

Country：Other  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2016.9

Language：Japanese  

Venue：Fukuoka   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：土岐、岐阜   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2016.8

Language：English  

Venue：Montreal   Country：Canada  

Event date： 2016.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Seoul   Country：Korea, Republic of  

Event date： 2016.7

Language：English  

Venue：Seoul  

Event date： 2016.7

Language：English  

Venue：Seoul  

Event date： 2016.7

Language：English  

Venue：Changsha   Country：China  

Event date： 2016.6

Language：English  

Venue：Crete   Country：Greece  

Event date： 2016.6 - 2016.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：新潟   Country：Japan  

Event date： 2016.5

Language：English  

Venue：Kobe   Country：Japan  

Event date： 2016.5

Language：English  

Venue：Kobe   Country：Japan  

Event date： 2016.5

Language：English  

Venue：Kobe   Country：Japan  

Event date： 2016.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Kobe   Country：Japan  

Event date： 2016.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Kobe   Country：Japan  

Event date： 2016.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Okinawa   Country：Japan  

Event date： 2016.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2016.4

Language：English  

Venue：Paris   Country：France  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2015.11

Language：English  

Venue：Kobe   Country：Japan  

Scientific visualization has matured over the last two decades with the accumulation of knowledge and expertise from various field of research. High performance visualization is therefore built on top of various related underlying methods and techniques from different fields. Usually, the HPC (High Performance Computing) users have more specific needs than general ones, and besides the formulation of new visualization methodologies and approaches, it becomes crucial to actually implement and deliver these visualization capabilities to the end users. This development process is usually a long-term activity thus it requires a long-term software development and maintenance process. Therefore, the system design is required to cope with the dynamic changes in the computer architecture of the HPC systems over the years. A flexible visualization framework which can cope with these architectural changing, can interact with different hardware devices, and can easily be aggregated with other visualization methodologies becomes highly necessary. In addition, it is desired to be capable of adapting and coordinating with different post-processing requirements related to the changing in the use of HPC resources for better efficiency. We will describe the top three issues related to the design and development of this kind of visualization framework to deliver ubiquitous and sustainable High Performance Visualization capabilities.

Event date： 2015.10

Language：English  

Venue：Chicago   Country：United States  

Parallel numerical simulation is a powerful tool used by scientists to study complex problems. It has been a common practice to save the simulation output to disk and then conduct post-hoc in-depth analyses of the saved data. System I/O capabilities have not kept pace as simulations have scaled up over time, so a common approach has been to output only subsets of the data to reduce I/O. However, as we are entering the era of peta-and exa-scale computing, this sub-sampling approach is no longer acceptable because too much valuable information is lost. In situ visualization has been shown a promising approach to the data problem at extreme-scale. We present a novel in situ solution using depth maps to enable post-hoc image-based visualization and feature extraction and tracking. An interactive interface is provided to allow for fine-tuning the generation of depth maps during the course of a simulation run to better capture the features of interest. We use several applications including one actual simulation run on a Cray XE6 supercomputer to demonstrate the effectiveness of our approach.

Event date： 2015.7

Language：English  

Venue：Amsterdam   Country：Netherlands  

Binary-Swap is a parallel image compositing algorithm based on recursive vector halving and distance doubling, and works efficiently when the number of processes is exactly a power-of-two (2ⁿ). Several power-of-two converting approaches for Binary-Swap have been proposed. Among them, the Telescope method, based on the Binary Blocks algorithm, has been shown as the most promising approach. The Telescope method decomposes an entire set of processes into blocks of power-of-two size and merges the smaller blocks into larger blocks in stepwise fashion. This block merging process corresponds to the communication and computational overhead of the conversion, and since it can only merge one block per stage, it becomes inefficient as the number of binary blocks increases. In this paper, we focus on a single-stage conversion method using the 3-2 and 2-1 elimination approaches. The original scheduling method, proposed by Rabenseifner et al., is limited to an odd number of processes since it always schedules a single 3-2 elimination per conversion. Taking into consideration that the 3-2 elimination can be optimized on modern HPC systems, which can overlap the communication and computation, we propose 234 Scheduling for scheduling multiple 3-2 eliminations per conversion. The multiple 3-2 elimination scheduling enlarges the application range by enabling its use on an even number of processes. We evaluated 234 Scheduling applied to Binary-Swap on the K computer, which is a modern parallel HPC system, and confirmed its effectiveness.

Event date： 2014.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

This work describes a new approach to simulate the airflow and air-conditioning in the individual human nasal airways using voxel-based modeling with Cartesian structured grid. Computed tomography imaging scans of a healthy adult nose were used to reconstruct 3D virtual models of the nasal airways. Voxel-based simulation of quiet restful inspiratory flow was then performed using meshes of varying refinement to determine the level of mesh refinement required to adequately resolve the flow and heat transfer. For meshes with a voxel pitch of 0.20 mm or less, the voxel model successfully reconstruct the realistic nasal structure and simulate the overall pressure drop and airflow temperature. The resultant streamlines and vorticity distributions reveal the characteristic flow structure in the nasal cavities, with high speed jet posterior to the nasal valve, recirculating flow that occupies the anterior part of the upper cavity, and low speed flow in the olfactory region. It was also found that the impinging jet plays an important role in the air-conditioning performance in the nasal cavities.

Event date： 2014.7

Language：English  

Venue：Bologna   Country：Italy  

High performance visualization has played an important role in computer-aided scientific discovery and has become an indispensable tool for computational scientists. Sort-last parallel rendering is a proven approach for visual data analytics by extracting meaningful information from huge data sets generated from large scale scientific computing. Image compositing is the last stage of sort-last parallel rendering pipeline and works by combining the images generated by the rendering nodes to generate the final image. Since it requires interprocess communication among the entire nodes, it usually dominates the total cost of the parallel rendering process. In current high-end massively parallel HPC systems, where tens or even hundreds of thousands of nodes can be involved, performance degradation is inevitable even using theoretically scalable image compositing algortithms such as the well-known Binary-Swap method. To minimize this undesirable performance degradation, we propose the multi-step image compositing method, where the image compositing nodes are divided into smaller groups and the entire process is performed in several steps. We evaluated the proposed image compositing method on RIKEN K computer, which is a massively parallel HPC system, and we obtained encouraging results showing the effectiveness of this method in a large-scale image compositing environment. We also foresee a great potential of this method to meet the large-scale image compositing demands brought about by the rapid increase in processor counts of current and next-generation HPC systems.

Event date： 2014.6 - 2014.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Eugene   Country：United States  

Practical simulators require high-performance iterative methods and efficient boundary conditions, especially in the field of computational fluid dynamics. In this paper, we propose a novel bitrepresentation technique to enhance the performance of such simulators. The technique is applied to an iterative kernel implementation that treats various boundary conditions in a stencil computation on a structured grid system. This approach reduces traffic from the main memory to CPU, and effectively utilizes Single Instruction–Multiple Data (SIMD) stream units with cache because of the bit-representation and compression of matrix elements. The proposed implementation also replaces if-branch statements with mask operations using the bit expression. This promotes the optimization of code during compilation and runtime. To evaluate the performance of the proposed implementation, we employ the Red–Black SOR and BiCGstab algorithms. Experimental results show that the proposed approach is up to 3.5 times faster than a naïve implementation on both the Intel and Fujitsu Sparc architectures.

Event date： 2014.6 - 2014.7

Language：English  

Venue：Anchorage   Country：United States  

Thanks to the supercomputer, more and more complicated simulations are successfully achieved. On the other hand, to analyze and understand the intrinsic properties of the big datasets from the simulations is an urgent research for scientists. However, the explosive size of the big datasets makes such kind of task difficult. Therefore, reduction of the size of the big datasets becomes an important topic, in which data compression and parallel computing are the two key techniques. In this paper, we presented a parallel data compression approach to reduce the size of time-varying big datasets. Firstly, we employ the proper orthogonal decomposition (POD) method for compression. The POD method can extract the underlying features of datasets to greatly reduce the size of big datasets. Meanwhile, the compressed datasets can be decompressed linearly. This feature can help scientists to interactively visualize big datasets for analysis. Then, we introduced a novel m-swap method to effectively parallelize the POD compression algorithm. The m-swap method can reach a high performance through fully using all parallel computing processors. In another word, no idle processors exist in the parallel compression process. Furthermore, the m-swap method can greatly reduce the cost of interprocessor communication. This is achieved by controlling the data transfer among 2m processors to obtain the best balance of computation cost of these processors. Finally, the effectiveness of our method will be demonstrated through compressing several time-varying big datasets on the K computer with ten thousands of processors.

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Seoul   Country：Korea, Republic of  

Significant gap between software programming model and execution model is one major slowing factor in the development of the emerging field of Internet-of-Things. It is also one of the main reasons why software systems often lag behind hardware technologies and fail to capture the full potentials of modern day hardware infrastructure, which is mostly parallel and distributed. We need to change the way we think about software fundamentally, and make it, at its most basic level, to work like the physical world works: distributed, parallel, loosely connected, and asynchronous. KnoRBA achieves this by making the basic components of any program, such as a common word processor, to be asynchronous mobile agents. Then through provision of implementation and location transparency it establishes integration across a distributed environment. This extended abstract is an early introduction to the new revision of KnoRBA that makes it efficient in a domain like sensor networks where power and bandwidth are critical factors.

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Yokohama, Kanagawa   Country：Japan  

The development of supercomputers has successfully helped us to carry on complicated simulation with exploded size of dataset. For visualizing such kind of large-scale dataset, reducing the data size by using compression methods is one of the most useful approach. Moreover, parallelization of compression algorithm can greatly improve the efficiency and resolve the limitation of memory size. However, in parallel compression algorithm, interprocessor communication is indispensable, while it is also a bottleneck problem, especially for the general cases that the number of processors is not power-of-Two. Parallel POD (proper orthogonal decomposition) compression algorithm is such an example, the number of time steps must be power-of-Two for the binary swap scheme. A method that can fully resolve this problem with low computational cost will be very popular. In this paper, we proposed such an approach called 2-3-4 combination approach, which can be simply implemented and also reach high performance of parallel computing algorithms. Furthermore, our method can obtain the best balance among all parallel computing processors. This is achieved by transferring the non-power-of-Two problem into power-of-Two problem to fully use the best balance feature of binary swap method. We evaluate our approach through applying it to the parallel POD compression algorithm on the K computer.

Event date： 2013.10

Language：English  

Venue：Atlanta, GA   Country：United States  

The development of supercomputers has greatly help us to carry on large-scale computing for dealing with various problems through simulating and analyzing them. Visualization is an indispensable tool to understand the properties of the data from supercomputers. Especially, interactive visualization can help us to analyze data from various viewpoints and even to find out some local small but important features. However, it is still difficult to interactively visualize such kind of big data directly due to the slow file I/O problem and the limitation of memory size. For resolving these problems, we proposed a parallel compression method to reduce the data size with low computational cost. Furthermore, the fast linear decompression process is another merit for interactive visualization. Our method uses proper orthogonal decomposition (POD) to compress data because it can effectively extract important features from the data and the resulting compressed data can also be linearly decompressed. Our implementation achieves high parallel efficiency with a binary load-distributed approach, which is similar to the binary-swap image composition used in parallel volume rendering [2]. This approach allows us to effectively utilize all the processing nodes and reduce the interprocessor communication cost throughout the parallel compression calculations. Our test results on the K computer demonstrate superior performance of our design and implementation.

Event date： 2012.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Kobe   Country：Japan  

Peta-scale supercomputers enable us to tackle very large-scale problems of which results provide useful information to understand physical phenomena or to improve performance of a product design. The large-scale simulation is becoming dawn to earth due to parallel computing techniques, however, inherent barriers on the distributed parallel environment are still remains in simulation process, i.e., grid generation, visualization and data analysis. In this paper, the authors would like to clarify the issues to be resolved for productive support environment of the large-scale simulation, and to propose a foundational framework to enhance the utilization of huge computational resources.

Event date： 2012.7

Language：English  

Venue：Rethymnon, Crete   Country：Greece  

Generating quadrilateral meshes is very important in many industrial applications such as finite element analysis and B-spline surface fitting. However, it is still a challenging task to design appropriate vertex connectivity in the quadrilateral meshes by respecting the shapes of the target object and its boundary. This paper presents an approach for interactively editing such mesh topology in quadrilateral meshes by introducing a 2D diffusion tensor field to the interior of the target object. The primary idea is to track the two principal directions of the tensor field first and then construct the dual graph of the quadrilateral mesh, so that we can control the mesh topology through the design of the underlying 2D diffusion tensor field. Our method provides interactive control of such mesh topology through editing the orientations of the tensor samples on the boundary of the target object. Furthermore, it also allows us to intentionally embed degeneracy inside the object to introduce extraordinary (i.e., non-degree-four) vertices according to user requirements.

Event date： 2011.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Kos   Country：Greece  

Impact of injecting microbubbles on the thermal expansion due to the nuclear spallation reaction were examined numerically. Since the mercury density is higher than the density of solid wall, the interaction between mercury and solid wall must be taken into account. Our approach is to solve the momentum and energy conservation equations and the time development of elastic stress for both bubbly fluid and elastic solid. The Keller equation is employed to reproduce the nonlinear oscillation of bubble with considering the thermal dumping effect by the reduced order model. The continuum phase of liquid mercury is coupled with the discrete phase of microbubbles using the Euler-Lagrange method. As the results, the bubble cloud develops around the center of inertia of motion induced by the thermal expansion. The elasticity of the wall affects on the migration of the center of inertia away from the wall. The injection of microbubbles is effective to decrease the pressure rise due to thermal expansion for both rigid and elastic wall conditions when the void fraction of microbubbles is higher than the volume rate of thermal expansion of liquid mercury.

Event date： 2010.12

Language：English  

Venue：Seoul   Country：Korea, Republic of  

We propose a novel cloth modeling method to simulate dyeing techniques. Morimoto et al. [2007] proposed a physics-based dyeing simulation method. To simulate dyeing techniques in conjunction with folded 3D cloth geometries, we developed a natural and intuitive method to generate cloth geometries. This method uses locally applied geometric operations for multiple dyed patterns on a cloth and a Voronoi diagram based stitching algorithm for cloth gathering. It is not intuitive to generate some folded cloth geometries with one cloth, due to the requisite complexity of the cloth geometry. Instead, we implemented a novel sketch-based interface to divide a cloth patch for local geometric operation and for independent stitching operations. Our method provide an intuitive design platform for dyeing patterns.

Event date： 2010.11 - 2010.12

Language：English  

Venue：Las Vegas, NV   Country：United States  

Hand dyeing generates artistic representations with unique and complex patterns. The aesthetics of dyed patterns on a cloth originate from the physical properties of dyeing in the cloth and the geometric operations of the cloth. Although many artistic representations have been studied in the field of non-photorealistic rendering, dyeing remains a challenging and attractive topic. In this paper, we propose a new framework for simulating dyeing techniques that considers the geometry of the folded cloth. Our simulation framework of dyeing in folded woven cloth is based on a novel dye transfer model that considers diffusion, adsorption, and supply. The dye transfer model is discretized on a 3D graph to approximate the folded woven cloth designed by user interactions. We also develop new methods for dip dyeing and tie-dyeing effects. Comparisons of our simulated results with real dyeing demonstrate that our simulation is capable of representing characteristics of dyeing.

Event date： 2010.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Iwate   Country：Japan  

Various applications have been found for the ability to use computers to display the shape of archaeological objects, such as earthenware vessels, earthenware figurines and stone vessels. These applications include the technology used for creating survey maps, making precise measurements, preparing replicas and creating web content. However, since surface measurements are commonly conducted using lasers or with the stylus method, it is difficult to measure complex surfaces, internal configurations, thicknesses and volumes. In the present research, with regard to easily breakable earthenware vessels, earthenware figurines and stone vessels, we propose a method for easy storing of accurate 3D data obtained with an industrial X-ray computed tomography (CT) device. The 3D surface image obtained can be used for measuring the thickness and volume of earthenware vessels, for reproducing their shapes by using polygons, and for constructing high-resolution surface models. The present method has been utilized for measurements of actual archaeological objects, for the preparation of duplicates (replicas), and for the creation of web content, and its effectiveness has been verified.

Event date： 2010.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Montreal, QC   Country：Canada  

Computational fluid dynamics (CFD) is now widely used as an essential tool in the development of automotive aerodynamics. However, the time required for repairing non-watertight geometries has recently become a serious problem in current CFD processes. Therefore, we developed an efficient simulation method that allows the flow around a non-watertight geometry to be computed on a Cartesian grid. This method can substantially reduce the turnaround time and effort required for CFD processes, because the repair work can be eliminated. The proposed method adopts an embedded boundary condition technique to capture arbitrary shapes more accurately on the background Cartesian grid. In addition, a local mesh refinement technique enables higher computational efficiency to be realized, and large-eddy simulation (LES) is used to reproduce high-Reynolds-number turbulent flow. Preliminary tests were performed on an engine bay configuration that had non-watertight geometries and a 1/5-scale model of an automobile configuration. As a result, the proposed method was confirmed to enable rapid grid generation and flow simulation around non-watertight geometries. Moreover, the computed results showed good agreement with experimental data.

Event date： 2010.6

Language：English  

Venue：Tokyo   Country：Japan  

The effective combination of microbubbles and ultrasound in HIFU therapy has been investigated through a numerical simulation. The equations for conservation of mass, momentum and energy are solved for a microbubble-infused mixture, and model HIFU therapy in the presence of microbubbles. The bubbles follow Rayleigh-Plesset equation, and are coupled with the mixture using the Euler-Lagrange method. The impacts of both the volume fraction due to the microbubbles and the amplitude of the ultrasound on the heat distribution are analyzed by using a two dimensional cylindrical simulation of the propagation of focused ultrasound (1MHz) through a mixture of bubbles 1.3mm in diameter. As the initial void fraction increased, the shape of the high temperature region was observed to change from cigar shape, to tadpole shaped, to cone shape. It was numerically confirmed that the temperature dramatically increased by means of inertial cavitation. The results show that the effectiveness of HIFU therapy increases with increased initial void fraction, as well as an input ultrasound amplitude above the threshold required for inertial cavitation.

Event date： 2010.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Waltham, MA   Country：United States  

We propose a two-handed direct manipulation system to achieve complex volume segmentation of CT/MRI data in Augmented Reality with a remote controller attached to a motion tracking cube. At the same time segmented data is displayed by direct volume rendering using a programmable GPU. Our system achieves visualization of real time modification of volume data with complex shading including transparency control by changing transfer functions, displaying any cross section, and rendering multi materials using a local illumination model. Our goal is to build a system that facilitates direct manipulation of volumetric CT/MRI data for segmentation in Augmented Reality. Volume segmentation is a challenging problem and segmented data has an important role for visualization and analysis.

Event date： 2009.12

Language：English  

Venue：Yokohama   Country：Japan  

We present a novel method to simulate tie-dyeing patterns considering 3D folded cloth geometry with user interaction. Morimoto et al. propose a dye transfer model that accounts for dyeing theories by considering parameters of weave structure, dyestuffs and cloth [Morimoto et al. 2007]. However this model does not consider a behavior of dye and distribution of protection against dyeing in 3D cloth geometry. We improve this model to consider 3D folded cloth geometry. In the process of tie-dyeing, cloth is folded and tied, and then dipped into dye bath. In a dyebath, the dyestuffs penetrate from the outside surface parts of folded cloth that are exposed to the dyebath directly. The other fluttery parts of the cloth possibly become the surface parts in the dyebath. Our method calculates such fluttery parts and the ratio to supply dyestuffs of the parts. Also, our dye diffusion model considers edges by folding cloth. This technique enables to obtain various tie-dyeing patterns from simple user inputs while it is difficult to predict the final figure of real tie-dyeing.

Event date： 2009.12

Language：English  

Venue：Yokohama   Country：Japan  

We propose a novel two-handed direct manipulation system to achieve complex volume segmentation of CT/MRI data in the real 3D space with a remote controller attached a motion tracking cube. At the same time segmented data is displayed by direct volume rendering using a programmable GPU. Our system achieves visualization of real time modification of volume data with complex shadings including transparency control by changing transfer functions, displaying any cross section and rendering multi materials using a local illumination model.

Event date： 2009.11

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Karlsruhe   Country：Germany  

The Reality of Virtual Reality is affected by many research areas. Therefore, individual researches must be combined to achieve the extreme goal of Virtual Reality. In this paper, we present an application of the novel and clever combination of height field wave simulation, photo realistic rendering, and a 6DOF manipulator exploiting Augmented Reality. In our system, a user can touch a virtual water surface with a real pen attached a tracking cube in natural manners. We also take into account rendering optical effects like shadows and caustics, which give users a great deal of reality. We show how such a combination is important to achieve reality in the videos of our real time demonstrations.

Event date： 2009.9

Language：English  

Venue：Aix-en-Provence   Country：France  

The development of the HIFU therapy for the deeply placed cancer has been desired. On problem is the displacement of the focal point due to the inhomogeneity of human body. The objectives are to realize the appropriate phase control of an array transducer and to support the preoperative planning of HIFU therapy by the computational prediction of treatment regions. Our approach is to solve the mass and momentum equations for mixture with the equation of state of media. The heat equation with a heat source of a viscous dissipation is solved to estimate the ablation region of tissue. The ablation, i.e., the heat denaturation of protein, is modeled as a phase transition by the phase field model. The HIFU therapy with a bowl-shape array transducer for a liver cancer is simulated. As the result with a phase control, we obtain a clear focus which is closer to a target point than the focus without a phase control, when the ultrasound propagates through lib bones. In addition, the development of the ablation region is reproduced numerically.

Event date： 2008.11

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Austin, TX   Country：United States  

Scientific data processing and visualization of computational simulation data have played an important role in knowledge creation, and its transfer for the benefit of society, through scientific discovery and understanding of physical and chemical phenomena. Massively parallel processing architecture has greatly contributed to increase the computational power and to enlarge the scale of computation. This facilitated the generation of larger and larger amounts of data. To tackle this oncoming tsunami of data, we propose a post-processing system for large-scale data focusing on the idea that a postprocessing system needs to be an assistant of the researchers thinking process. We present a probable design solution targeting continuous development, and the technologies for productivity improvement such as collaborative work and visualization. This paper describes the current development status of a postprocessing system designed for the next-generation 10-petaflop supercomputer under development in Japan.

Event date： 2008.5

Language：English  

Venue：Lyon   Country：France  

Elliptic partial difference equations like Poisson's equation are used in many fields of application. However, the coefficientmatrix of the derived algebraic equation is large and sparse, and so its inversion is expensive. Various iterative methods are used to solve such a sparse matrix system. Although there have been many studies on solving the large sparse matrix system [1, 2, 3, 4, 5, 6, 7], there have been few reports on the implementation and performance of the iterative method with multicolor ordering. In this paper, a novel implementation technique to enhance the performance of the 2-colored SOR method is proposed, which eliminates the recursion for the standard 7-point stencil on the Cartesian grid in three dimensions. The performance of the multicolor SOR method is investigated on both a shared memory vector/parallel computer and a symmetric multiprocessor machine in a distributed memory environment.

Event date： 2007.7 - 2007.8

Language：English   Presentation type：Oral presentation (general)  

Venue：San Diego, CA   Country：United States  

A compressible flow solver coupled with moving/deformed geometries on Cartesian grid with Signed Distance Field (SDF) is developed and its capability is investigated through computations of several basic flow fields for future applications with certain reliability. The flow solver is designed so that SDF includes sufficient geometrical information to compute flow fields. Since information of moving/deformed geometries is recognized as a change of the SDF between time steps, the flow solver can be coupled with moving/deformed geometries naturally. The implementation of this solver is simple and easy. No modification is needed in the main part of the flow solver. Furthermore, the interpolation and the corresponding stencils searching process are not required. Several basic flow fields around fixed/moving cylinders and a fixed sphere are computed in order to validate the proposed solver, in which the computed results are compared with available numerical and experimental results. The results demonstrated the method's capability for moderate Reynolds number flows around both of fixed and moving geometries. Based on the results, some criteria and problems for obtaining reliable solution are suggested.

Event date： 2007.5

Language：English  

Venue：Antalya   Country：Turkey  

Event date： 2006.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Ghent   Country：Belgium  

Event date： 2005.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

B206 The Blood flow simulation of the head blood vessel, based on the medical image

Event date： 2004.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Los Angeles, CA   Country：United States  

A gaze-directed streamline seeding technique technique based on eye-tracking data is discussed. The process starts by asking a user to observe the LIC image of a 2D flow field for a few seconds. The data from eye-tracker are analyzed to obtain a set of fixations {fix _i = (s _i, y _i, t _i) i ∈ [1...]} with (x _i, y _i) being the position and t _i, and the duration _i. Fixations are depicted with the circles, with their centers being the position of fixation and their radius representing the duration.

Event date： 2003.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

This paper describes the design and performance of an interactive visualization system developed specifically for improved understanding of time-varying volume data from thermal flow simulations for vehicle cabin and ventilation design. The system uses compression to allows for better memory utilization and faster data transfer, hardware accelerated rendering to enable interactive exploration, and an intuitive user interface to support comparative visualization. In particular, the interactive exploration capability offered by the system raises scientists to a new level of insight and comprehension. Compared to a previous visualization solution, such a system helps scientists more quickly identify and correct design problems.

Event date： 2002.3

Language：English  

Venue：Detroit, MI   Country：United States  

This paper reviews a validation project on CFD commercial codes organized by Society of Automobile Engineers of Japan (JSAE) in 2001. As benchmark problems, four major objects of vehicle flow design are selected for Vehicle aerodynamics, Engine cylinder flow, Air-conditioning and Defroster duct flow. 14 titles of commercial software sold in Japan are applied to these problems. The results of each problem are compared with reference experimental data and evaluated in vi ews of vehicle design and development. Feasibility of auto-meshing techniques and computation cost in recent hardware are also discussed.

Event date： 1992.2

Language：English  

Venue：Detroit, MI   Country：United States  

Both the external and internal flows of cars are simulated simultaneously. A third-order upwind-difference scheme is used in these simulations. Computational grids are generated by a multi-block transformation and a trans-finite method. Engine compartments are modeled by grid systems but the heat exchanger is simulated as a pressure loss proportional to the dynamic pressure of the flow passing through it. First, the flow for a very simple test model with no wheels and nothing in its engine compartment is simulated and compared with experimental results in order to validate a simulation method for the engine compartment. Pressure distributions on the inner surfaces agree very well with measured values, while pressure distributions on the external surfaces show reasonable agreement except for the roof end and the leading edge of the floor. The predicted drag coefficient is 7% larger than the experimental value. This method is next applied to a prototype car. A grid system is generated including an engine block, a transmission, an air-cleaner and suspension arms. Both the drag coefficient and the airflow rate through the radiator are calculated. These values are compared with experimental results and the agreement is good. We conclude that the present method is quite useful for predicting and optimizing both the drag coefficient and the airflow rate through the radiator.

Language：Japanese  

Country：Other  

Online collaboration using the tiled display system ChOWDER

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

Unsteady Two-Dimensional CFD Analysis of Flow around a Circular Cylinder

Language：Japanese  

Country：Other  

Characteristics of Water Mist Fire Suppression Analysed by Numerical Calculation of Gas-Droplet Flow

Language：Japanese  

Country：Other  

Moving Boundary Handling in Cartesian Based Flow Solver Using Implicit Function

Language：Japanese  

Country：Other  

Voxel Based Thermal Fluid Analysis Using Implicit Function

Language：Japanese  

Country：Other  

Voxel based simulation with implicit function centered shape representation

Language：Japanese  

Country：Other  

Implementation of pFTT data structure to a library and performance evaluation

Language：Japanese  

Country：Other  

Development of numerical techniques for the assistance of high intensity focused ultrasound therapy

Language：Japanese  

Country：Other  

Development of the ultrasound propagation simulator using living body information

Language：Japanese  

Country：Other  

Influence of the heat coagulation of tissue on the acoustic field in the high intensity focused ultrasound therapy

Language：Japanese  

Country：Other  

An Approach of Visual System Diagnosis using Semantic Logs

Language：Japanese  

Country：Other  

Language：Japanese  

Country：Other  

Gaze-Directed Flow Visualization

Language：Japanese  

Country：Other  

Voxel-based simulation of heat transfer between nasal airflow and mucosal vesseles

Language：Japanese  

Country：Other  

Development and applications of the parallel computing middleware for the life science simulations

Language：Japanese  

Country：Other  

J011011 Development of large-scale grid generation method for high-performance parallel fluid computation

Language：Japanese  

Country：Other  

Simulation of nasal air flow and temperature using a voxel model constructed directly from medical images

Language：Japanese  

Country：Other  

Numerical simulation of transitional flow in nasal cavity

Language：Japanese  

Country：Other  

Trends and prospects of research on parallel in time integration method

Language：Japanese  

Country：Other  

Numerical simulation of transitional flow in nasal cavity

Language：English  

Country：Other  

Currently, by default, integral curves are repeatedly re-computed in different flow visualization applications, such as FTLE field computation, source-destination queries, etc., leading to unnecessary resource cost. We present a compression-based data reuse framework for integral curves, to greatly reduce their retrieval cost, especially in a resource-limited environment. In our design, a hierarchical and hybrid compression scheme is proposed to balance three objectives, including high compression ratio, controllable error, and low decompression cost. Specifically, we use and combine digitized curve sparse representation, floating-point data compression, and octree space partitioning to adaptively achieve the objectives. Results have shown that our data reuse framework could acquire tens of times acceleration in the resource-limited environment compared to on-the-fly particle tracing, and keep controllable information loss. Moreover, our method could provide fast integral curve retrieval for more complex data, such as unstructured mesh data.

Language：Japanese  

Country：Other  

Language：Japanese  

Country：Other  

Language：Japanese  

Country：Other  

Language：Japanese  

Country：Other  

Design of AMR data structure considering efficiency and less footprint

Language：Japanese  

Country：Other  

The latest results of research and the future prospects of the parallel-in-time integration method

Language：Japanese  

Country：Other  

Estimation of Functions Representing Data Using Deep learning

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Language：English  

Country：Other  

Language：English  

Country：Other  

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Peer review 

Number of peer-reviewed articles in Japanese journals：1

Proceedings of International Conference Number of peer-reviewed papers：5

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Peer review 

Number of peer-reviewed articles in foreign language journals：2

Number of peer-reviewed articles in Japanese journals：2

Proceedings of International Conference Number of peer-reviewed papers：8

Proceedings of domestic conference Number of peer-reviewed papers：0

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Number of participants：130

Type：Competition, symposium, etc. 

Number of participants：128

Type：Scientific advice/Review