九州大学 研究者情報
論文一覧
小野 謙二(おの けんじ) データ更新日:2023.11.27

教授 /  情報基盤研究開発センター 応用データ科学研究部門 システム情報科学研究院情報理工学専攻


原著論文
1. Xin Liang, Sheng Di, Franck Cappello, Mukund Raj, Chunhui Liu, Kenji Ono, Zizhong Chen, Tom Peterka, Hanqi Guo, Toward Feature-Preserving Vector Field Compression, IEEE Transactions on Visualization and Computer Graphics, 10.1109/TVCG.2022.3214821, 2022.10.
2. Shiyao Xie, Akinori Miura, Kenji Ono, Error-bounded Scalable Parallel Tensor Train Decomposition, 25th Workshop on Advances in Parallel and Distributed Computational Models to be held in conjunction with
37th IEEE International Parallel and Distributed Processing Symposium
IPDPS May 15-19, 2023, St. Petersburg, Florida, USA
, 2023.05.
3. Xiaoqing Liu, Kenji Ono, Ryoma  Bise, Mixing Data Augmentation with Preserving Foreground Regions in Medical Image Segmentation, 2023 IEEE 20th International Symposium on Biomedical Imaging (ISBI), 2023.04.
4. T. Mitsuda, K. Ono, A Scalable Parallel Partition Tridiagonal Solver for Many-Core and Low B/F Processors, 2022 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW), 10.1109/IPDPSW55747.2022.00142, 860-869, 2022.06.
5. 宮城 充宏,山本 肇,飯塚 幹夫, 小野 謙二, 時間並列計算手法 Parareal 法による地下水流動シミュレーションの高速化, Transactions of JSCES, 2021.08, [URL].
6. Hagita, Katsumi, Murashima, Takahiro, Ogino, Masao, Omiya, Manabu, Ono, Kenji, Deguchi, Tetsuo, Jinnai, Hiroshi and Kawakatsu, Toshihiro, Efficient compressed database of equilibrated configurations of ring-linear polymer blends for MD simulations, Scientific Data, https://doi.org/10.1038/s41597-022-01138-3, 9, 40, 2022.02, To effectively archive configuration data during molecular dynamics (MD) simulations of polymer systems, we present an efficient compression method with good numerical accuracy that preserves the topology of ring-linear polymer blends. To compress the fraction of floating-point data, we used the Jointed Hierarchical Precision Compression Number - Data Format (JHPCN-DF) method to apply zero padding for the tailing fraction bits, which did not affect the numerical accuracy, then compressed the data with Huffman coding. We also provided a dataset of well-equilibrated configurations of MD simulations for ring-linear polymer blends with various lengths of linear and ring polymers, including ring complexes composed of multiple rings such as polycatenane. We executed 109 MD steps to obtain 150 equilibrated configurations. The combination of JHPCN-DF and SZ compression achieved the best compression ratio for all cases. Therefore, the proposed method enables efficient archiving of MD trajectories. Moreover, the publicly available dataset of ring-linear polymer blends can be employed for studies of mathematical methods, including topology analysis and data compression, as well as MD simulations..
7. Tomohiro Kawanabe, Kazuma Hatta, Kenji Ono, ChOWDER - A New Approach for Viewing 3D Web GIS on Ultra-High-Resolution Scalable Display, 2020 IEEE International Conference on Cluster Computing, CLUSTER 2020, 412-413, 9229604, 2020.09, [URL], 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..
8. 小野謙二,古賀壱成, 遺伝的プログラミングによる支配方程式の推定, Transactions of JSCES, https://doi.org/10.11421/jsces.2020.20201004, 2020.11.
9. Xin Liang, Hanqi Guo, Sheng Di, Franck Cappello, Mukund Raj, Chunhui Liu, Kenji Ono, Zizhong Chen, Tom Peterka, Toward Feature-Preserving 2D and 3D Vector Field Compression, 13th IEEE Pacific Visualization Symposium, PacificVis 2020
2020 IEEE Pacific Visualization Symposium, PacificVis 2020 - Proceedings
, 10.1109/PacificVis48177.2020.6431, 81-90, 2020.06, [URL], 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..
10. Issei Koga, Kenji Ono, Effective pre-processing of genetic programming for solving symbolic regression in equation extraction, 12th International Workshop on Information Search, Integration and Personalization, ISIP 2018
Information Search, Integration, and Personalization - 12th International Workshop, ISIP 2018, Revised Selected Papers
, 10.1007/978-3-030-30284-9_6, 89-103, 2019.01, [URL], 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..
11. Tomohiro Kawanabe, Jorji Nonaka, Daisuke Sakurai, Kazuma Hatta, Shuhei Okayama, Kenji Ono, Showing Ultra-High-Resolution Images in VDA-Based Scalable Displays, 16th International Conference on Cooperative Design, Visualization, and Engineering, CDVE 2019
Cooperative Design, Visualization, and Engineering - 16th International Conference, CDVE 2019, Proceedings
, 10.1007/978-3-030-30949-7_13, 116-122, 2019.10, [URL], 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..
12. 清水 崇文, 平井 康幸, 木村 真也, 世良 俊博, 横田 秀夫, 小野 謙二, 田中 学, 嗅動作時における鼻腔内流れのボクセルシミュレーション, バイオエンジニアリング講演会講演論文集, 10.1299/jsmebio.2019.31.1G22, 2019, 0, 1G22, 2019.03, [URL].
13. Issei Koga, Kenji Ono, Effective Pre-processing of Genetic Programming for Solving Symbolic Regression in Equation Extraction, Communications in Computer and Information Science, 1040, 89-103, 2019.08, 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..
14. Shinya Kimura, Yusuke Kimura, Toshihiro Sera, Kenji Ono, Gaku Tanaka, Voxel-based simulation of nasal airflow during a sniff, Transactions of Japanese Society for Medical and Biological Engineering, 10.11239/jsmbe.56.37, 56, 2, 37-43, 2018.01, [URL], 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..
15. Kenji Ono, Jorji Nonaka, Hiroyuki Yoshikawa, Takeshi Nanri, Yoshiyuki Morie, Tomohiro Kawanabe, Fumiyoshi Shoji, Design of a Flexible In Situ Framework with a Temporal Buffer for Data Processing and Visualization of Time-Varying Datasets, International Conference on High Performance Computing, ISC High Performance 2018
High Performance Computing - ISC High Performance 2018 International Workshops, Revised Selected Papers
, 10.1007/978-3-030-02465-9_17, 243-257, 2018.01, [URL], 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..
16. Jorji Nonaka, Kenji Ono, Naohisa Sakamoto, Kengo Hayashi, Motohiko Matsuda, Fumiyoshi Shoji, Kentaro Oku, Masahiro Fujita, Kazuma Hatta, A Large Data Visualization Framework for SPARC64 fx HPC Systems-Case Study
K Computer Operational Environment-, 8th IEEE Symposium on Large Data Analysis and Visualization, LDAV 2018
2018 IEEE 8th Symposium on Large Data Analysis and Visualization, LDAV 2018
, 10.1109/LDAV.2018.8739214, 108-109, 2018.10, [URL], 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..
17. Shinya Kimura, Takashi Sakamoto, Toshihiro Sera, Hideo Yokota, Kenji Ono, Denis J. Doorly, Robert C. Schroter, Gaku Tanaka, Voxel-based modeling of airflow in the human nasal cavity, Computer Methods in Biomechanics and Biomedical Engineering, 10.1080/10255842.2018.1555584, 22, 3, 331-339, 2019.02, [URL], 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..
18. Kenji Ono, Jorji Nonaka, Hiroyuki Yoshikawa, Takeshi Nanri, Yoshiyuki Morie, Tomohiro Kawanabe, Fumiyoshi Shoji, Design of a Flexible In Situ Framework with a Temporal Buffer for Data Processing and Visualization of Time-Varying Datasets, Lecture Notes in Computer Science, 11203, 243-257, 2019.01.
19. Kenji Ono, Takanori Uchida, High-Performance Parallel Simulation of Airflow for Complex Terrain Surface, Modelling and Simulation in Engineering, 10.1155/2019/5231839, 2019, 2019.02, [URL], 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..
20. 田中 俊太朗, 原田 利宣, 小野 謙二, 畳み込みニューラルネットワークを用いた自動車の三次元モデルにおける各車型の特徴抽出と視覚化, 日本感性工学会論文誌, 10.5057/jjske.TJSKE-D-18-00039, 18, 1, 113-121, 2019.01, [URL], The cars are classified by cars' body types. However the characteristics are basically similar at first sight, so it is difficult to distinguish the differences among those cars' body types. Therefore, in this study, we considered that cars' characteristics could be analyzed by using deep learning and image recognition technology, developed a system to visualize the judgment and characteristic parts of cars' body types. Specifically, we made renderings of the CG model of 30 cars by setting 360 viewpoints in 1 degree increments around each car. Deep learning was performed using these 2D images as teacher signals. The car body type recognition probability of each angle is graphed, and the characteristic parts of each car body type are visualized. As a result, we clarified the visual angles and the pars contributing the judgment of cars' body types..
21. Kazunori Mikami, Kenji Ono, Jorji Nonaka, Performance evaluation and visualization of scientific applications using PMlib, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018
Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018
, 10.1109/CANDARW.2018.00053, 243-249, 2018.12, [URL], 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..
22. Eduardo C. Inacio, Jorji Nonaka, Kenji Ono, Mario A.R. Dantas, Fumiyoshi Shoji, Characterizing I/O and Storage Activity on the K Computer for Post-Processing Purposes, 2018 IEEE Symposium on Computers and Communications, ISCC 2018
2018 IEEE Symposium on Computers and Communications, ISCC 2018
, 10.1109/ISCC.2018.8538488, 2018-June, 730-735, 2018.11, [URL], 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..
23. Tomohiro Kawanabe, Jorji Nonaka, Kenji Ono, Chowder
Dynamic contents sharing through remote tiled display system, 11th International Symposium on Visual Information Communication and Interaction, VINCI 2018
VINCI 2018 - 11th International Symposium on Visual Information Communication and Interaction
, 10.1145/3231622.3232504, 108-109, 2018.08, [URL], 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..
24. Takeshi Nanri, Satoshi Ohshima, Kenji Ono, Mellanox社のスイッチ装置への集団通信オフロード機能による集団通信隠蔽効果の調査, 研究報告ハイパフォーマンスコンピューティング(HPC), 165, 12, 1-10, 2018.07.
25. Jorji Nonaka, Kenji Ono, Masahiro Fujita, 234Compositor
A flexible parallel image compositing framework for massively parallel visualization environments, Future Generation Computer Systems, 10.1016/j.future.2017.02.011, 82, 647-655, 2018.05, [URL], 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..
26. Mikio Iizuka, Kenji Ono, Influence of the phase accuracy of the coarse solver calculation on the convergence of the parareal method iteration for hyperbolic PDEs, Computing and Visualization in Science, 2018.05.
27. Jorji Nonaka, Eduardo C. Inacio, Kenji Ono, Mario Dantas, Yasuhiro Kawashima, Tomohiro Kawanabe, Fumiyoshi Shoji, Data I/O management approach for the post-hoc visualization of big simulation data results, International Journal of Modeling, Simulation, and Scientific Computing, 10.1142/S1793962318400068, 2018.04, [URL].
28. Jorji Nonaka, Eduardo C. Inacio, Kenji Ono, Mario A.R. Dantas, Yasuhiro Kawashima, Tomohiro Kawanabe, Fumiyoshi Shoji, Data I/O management approach for the post-hoc visualization of big simulation data results, International Journal of Modeling, Simulation, and Scientific Computing, 10.1142/S1793962318400068, 2018.04, [URL], 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..
29. Tomohiro Kawanabe, Jorji Nonaka, Kazuma Hatta, Kenji Ono, ChOWDER
An adaptive tiled display wall driver for dynamic remote collaboration, 15th International Conference on Cooperative Design, Visualization, and Engineering, CDVE 2018
Cooperative Design, Visualization, and Engineering - 15th International Conference, CDVE 2018, Proceedings
, 10.1007/978-3-030-00560-3_2, 11-15, 2018.01, [URL], 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..
30. Fan Hong, Chongke Bi, Hanqi Guo, Kenji Ono, Xiaoru Yuan, Compression-based integral curve data reuse framework for flow visualization, Journal of Visualization, 10.1007/s12650-017-0428-4, 20, 4, 859-874, 2017.11, [URL], 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..
31. Fan Hong, Chongke Bi, Hanqi Guo, Kenji Ono, Xiaoru Yuan, Compression-based integral curve data reuse framework for flow visualization, Journal of Visualization, 10.1007/s12650-017-0428-4, 20, 4, 859-874, 2017.11, [URL], 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..
32. Ryo Takenoshita, Toshinobu Harada, Kenji Ono, データマイニングを用いた2種類の酒類におけるWeb上の感性情報の比較と視覚化, 日本感性工学会論文誌, 10.5057/jjske.TJSKE-D-17-00052, 2017.08, [URL], In the plan of the products, affective information is utilized with diversification of a life style. Then, in this research, we developed the system that visualizes the difference in affective layered structures of two liquors' reviews (hereafter, visualization system). Specifically, the development consists of the following steps. (1) The visualization system extracts affective words from the reviews on the web. (2) We create the decision table in rough set theory using affective words. (3) The visualization system visualizes the difference in affective layered structures of two liquors using decision rules from each decision table. We conducted the evaluation experiment of the visualization system for 10 subjects. We made five subjects summarize comparison results of two liquors' reviews using the visualization system, and made remaining five subjects summarize them without it. Consequently, the usefulness of the visualization system was verified from the summarized contents and the creation time of them..
33. 今村 成吾, 飯塚 幹夫, Kenji Ono, 横川 三津夫, 大規模時空間並列計算でのParareal法の性能評価, 計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science, 22, 4p, 2017.05.
34. Kenji Ono, Daisuke Sakurai, Hamish Carr, Jorji Nonaka, Tomohiro Kawanabe, Flexible Fiber Surface: A Reeb-Free Approach, Topology-Based Methods in Visualization 2017 (TopoInVis 2017), 2017.02, 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..
35. 竹之下遼, 原田利宣, 小野 謙二, ラフ集合理論を用いた酒類に対するWeb上の感性情報の視覚化, 日本感性工学会論文誌, 10.5057/jjske.TJSKE-D-16-00057, 16, 1, 19-28, 2017.02, [URL], 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..
36. Ryo Takenoshita, Toshinobu Harada, Kenji Ono, Visualization of Affective Layered Structures of Liquors' Reviews on the Web using Rough Set Theory, 日本感性工学会論文誌, 10.5057/jjske.TJSKE-D-16-00057, 16, 1, 19-28, 2017.02, [URL], 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..
37. 今村 成吾, 小野 謙二, 飯塚幹夫, 横川 三津夫, Parareal法と領域分割法による拡散問題での時空間並列性能評価, 第157回ハイパフォーマンスコンピューティング, 19, 1-7, 2016-HPC-157, 2017.01.
38. 小野 謙二, 木村 祐介, 木村 真也, Toshihiro Sera, 田中 学, 嗅動作時における鼻腔内流れのボクセルシミュレーション, 生体医工学, 2016.10.
39. Kenji Ono, Takashi Shimizu, Naohisa Sakamoto, Jorji Nonaka, Koji Koyamada, Web-based Visualization System for Large-Scale Volume Datasets, The 35th JSST Annual Conference International Conference on Simulation Technology, 2016.10.
40. Kenji Ono, 可視化技術の進展と計算科学への貢献 (20周年記念号) -- (特集 計算工学の20年、これからの20年), 計算工学, 21, 4, 3392-3395, 2016.10.
41. Seigo Imamura, Kenji Ono, Mitsuo Yokokawa, Iterative-method performance evaluation for multiple vectors associated with a large-scale sparse matrix, International Journal of Computational Fluid Dynamics, 10.1080/10618562.2016.1234046, 30, 6, 395-401, 2016.07, [URL], 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..
42. Kenji Ono, 野中 丈士, 藤田 将洋, 奥 健太郎, 川鍋 友宏, 大規模並列可視化システムHIVEの開発, 計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science, 21, 4p, 2016.05.
43. 畑田 敏夫, Kenji Ono, 川鍋 友宏, HPCを利用したものづくり、その普及における課題と新しい試み
( 特集 HPCを利用した次世代ものづくり京を用いた先導事例), 計算工学, 20, 4, 3341-3344, 2015.10.
44. 磯部 光基, 木村 祐介, 木村 真也, Toshihiro Sera, 横田 秀夫, Kenji Ono, 田中 学, 鼻腔内熱流動ボクセル解析における横断面医療画像二次元補間の有効性, 生体医工学, 10.11239/jsmbe.53.160, 53, 3, 160-167, 2015.10, [URL], Nasal air flow and temperature were analyzed using a voxel model constructed directly from medical images. The nasal cavities of a healthy male were reconstructed using CT slices in the axial direction at an image resolution of 0.488 mm/pixel and a slice interval of 0.40 mm. The rough surfaces in the image, which were caused by the resolution, were smoothed using a bilinear interpolation algorithm. A voxel-based simulation of inspiratory flow was then performed with a voxel pitch of 0.20 mm. With an interpolation image resolution of 0.163 mm//pixel, the voxel model successfully simulated an overall pressure drop and airflow temperature to the same extent as the conventional boundary-fitted model..
45. Jorji Nonaka, Masahiro Fujita, Kenji Ono, Multi-Step Image Composition Approach for Sort-Last Massively Parallel Rendering, JASSE, 10.15748/jasse.2.108, 2, 1, 108-125, 2015.05, [URL], 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..
46. Kenji Ono, Ono Kenji, 理化学研究所計算科学研究機構 , Institute for Computational Science Advanced, 係数行列のビット表現による疎行列反復解法の高速化(注目研究in CFD28,第28回数値流体力学シンポジウム), ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 34, 2, 119-123, 2015.04.
47. Kenji Ono, 3・6 「京」の現状とエクサ級コンピュータ(3.計算力学,機械工学年鑑), 日本機械学會誌 = Journal of the Society of Mechanical Engineers, 117, 1149, 507, 2014.08.
48. Kenji Ono, 大西 順也, 超大規模熱流体計算のための100億超の階層的直交格子生成とその応用 (特集 スーパーコンピュータ「京」を利用した流体工学研究の新展開と機械工学関連の先端的産業応用事例), ターボ機械, 42, 5, 310-316, 2014.05.
49. 水谷 崇志, 磯部 光基, 田中 学, Toshihiro Sera, Kenji Ono, 医療画像に基づく鼻腔内熱流動のボクセルシミュレーション, 生体医工学, 10.11239/jsmbe.52.33, 52, 1, 33-41, 2014.05, [URL], This study describes a new approach to provide detailed quantification of the impact of surgical intervention on bilateral nasal airflow using voxel-based simulation. Computed tomography and magnetic resonance imaging scans were used to reconstruct 3D realistic models of both the pre- and post-operative 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 voxel pitches of 0.10 mm, the voxel model successfully simulated the overall pressure drop and airflow temperatures..
50. 荒木 冬人, 清水 駿, 田中 学, Toshihiro Sera, Kenji Ono, 横田 秀夫, 2G15 鼻腔内気流と粘膜間の熱伝達に関するボクセルシミュレーション(OS5-5:生体流れの計算バイオメカニクス:疾病の再現および診断・治療への応用(5)), バイオエンジニアリング講演会講演論文集, 2014, 26, 529-530, 2014.01.
51. Kenji Ono, Yasuhiro Kawashima, Tomohiro Kawanabe, Data centric framework for large-scale high-performance parallel computation, Procedia Computer Science, 10.1016/j.procs.2014.05.218, 29, 2336-2350, 2014.01, [URL], 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..
52. Shota Ishikawa, Haiyuan Wu, Chongke Bi, Qian Chen, Hirokazu Taki, Kenji Ono, Fluid data compression and ROI detection using run length method, Procedia Computer Science, 10.1016/j.procs.2014.08.228, 35, C, 1284-1291, 2014.01, [URL], 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..
53. 大西 順也, Kenji Ono, 鈴木 惣一朗, 階層型直交格子を用いた大規模流体シミュレーションの並列化, ハイパフォーマンスコンピューティングと計算科学シンポジウム論文集, 2014, 42-42, 2013.12.
54. Kenji Ono, 理化学研究所計算科学研究機構, 「京」特集の企画にあたって(京による最新計算事例の紹介), ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 32, 2, 137, 2013.04.
55. 水谷 崇志, 荒木 冬人, 小倉 裕章, 田中 学, Toshihiro Sera, Kenji Ono, 高木 周, D. J. Doorly, R. C. Schroter, 3E14 ボクセル熱流体シミュレーションによる鼻腔手術アセスメント(GS8:呼吸器系のバイオメカニクス), バイオエンジニアリング講演会講演論文集, 2013, 25, 607-608, 2013.01.
56. Satoshi Ito, Kazuya Goto, Kenji Ono, Automatically optimized core mapping to subdomains of domain decomposition method on multicore parallel environments, Computers and Fluids, 10.1016/j.compfluid.2012.04.024, 80, 1, 88-93, 2013.01, [URL], 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..
57. Hank Childs, Hans Christian Hege, Mark Hereld, Kenji Ono, David Rogers, Deborah Silver, Ultra vis 2012
2012 workshop on ultrascale visualization, 2012 SC Companion: High Performance Computing, Networking Storage and Analysis, SCC 2012
Proceedings - 2012 SC Companion: High Performance Computing, Networking Storage and Analysis, SCC 2012
, 10.1109/SC.Companion.2012.371, 2012.12, [URL].
58. Kenji Ono, 川鍋 智宏, 畑田 敏夫, F302 シミュレーションと設計をつなぐ技術
HPC/PFの構築と利用シナリオ(F3.「京」コンピュータと次世代ものづくり,フォーラム), 計算力学講演会講演論文集, 2012, 25, "F-44"-"F-45", 2012.10, シミュレーションの目的の一つとして、工業製品の設計支援がある。従来よりシミュレータ自身の開発・高精度化・高速化の点から様々な研究開発が行われ、シミュレーションの実行に関してプリポスト技術も進展してきた。近年、計算機のアーキテクチャが超並列によって性能向上を図る方向へ進み、シミュレータも超並列を考慮したアプリケーションの設計とチューニングの対応が必須となっている。この超並列化は、シミュレータ以上に周辺技術に大きく影響を与え、超並列対応のプリポスト技術の要請が高まっている。また、今後利用可能な巨大な計算機資源をどのように設計に活かすのか、シミュレーションの利用形態も大きく変化しようとしている。これらの動向を踏まえ、今後のシミュレーション環境を見据えた基盤技術について報告する。.
59. Kenji Ono, 水野 宏基, 向井 亨光, 超大規模ボクセル生成技術とシミュレータへのインターフェイスの開発, 計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science, 17, 4p, 2012.05.
60. Kenji Ono, 大規模数値計算における可視化技術の最先端, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.32.125_2, 32, 125, 52-57, 2012.04, [URL],   Visualization has great importance to extract essentials included in simulation data and to derive scientific discovery from the analyzed data. However, only perfurming simulation is not sufficient. Post processing, that is visualization and data analysis, is recognized as the very important basic technology that supports numerical simulation. Recently, K computer achieved the world fastest record in TOP500 and is anticipated its utilization in science and engineering fields. Extremely high parallelism and computation performance will be required for data processing and visualization algorithms since the high-end parallel supercomputer generates large-scale datasets. This paper describes the trend of post processing technology, which becomes more and more important..
61. Kenji Ono, 森西 洋平, 東京大学生産技術研究所 , 名古屋工業大学大学院工学研究科, 特集の企画にあたって(注目研究in CFD25,第25回数値流体力学シンポジウム), ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 31, 2, 111, 2012.04.
62. 太田 和生, 水谷 崇志, 荒木 冬人, 田中 学, Toshihiro Sera, 覚正 信徳, 横田 秀夫, Kenji Ono, 高木 周, 7H16 鼻腔内エアコンディショニング機能のボクセル熱流体解析(OS15 呼吸系のバイオメカニクス1), バイオエンジニアリング講演会講演論文集, 2012, 24, "7H16-1"-"7H16-2", 2012.01.
63. 橋本 学, Kenji Ono, 奥田 洋司, 402 レベルセットに基づいたLagrangian-Eulerian coupling methodの並列計算についての検討(OS4.大規模並列・連成解析と関連話題(1),OS・一般セッション講演), 計算力学講演会講演論文集, 2011, 24, 78-79, 2011.10.
64. 沖田 浩平, Kenji Ono, 符号付き距離関数を形状表現に用いた流体ソルバーの精度(距離と法線情報を利用した界面近傍における差分と補間の提案), Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.77.1813, 77, 781, 1813-1825, 2011.09, [URL], 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..
65. 瀬川 武彦, Kenji Ono, 深潟 康二, 産業技術総合研究所 , 東京大学生産技術研究所 , 慶應義塾大学理工学部, 特集の企画にあたって(地球惑星科学における流体現象1~地球内部編~), ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 30, 4, 291-292, 2011.08.
66. Y. Obikane, T. Nemoto, K. Ogura, M. Iwata, Kenji Ono, Using the V-Sphere Code for the passive scalar in the wake of a bluff body, World Academy of Science, Engineering and Technology, 77, 859-861, 2011.05, 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..
67. 太田 和生, 木村 真也, 田中 学, Toshihiro Sera, 覚正 信徳, 横田 秀夫, Kenji Ono, 高木 周, 鼻腔内流れの熱流体解析, 日本伝熱シンポジウム講演論文集, 10.11368/nhts.2011.0.253.0, 2011, 0, 253-253, 2011.05, [URL], 鼻腔は非常に複雑な形状をしており,吸入した空気を適切な温度に加温・冷却する温度調節機能などの重要な機能を保持している.従来の鼻腔内流れの熱流体解析では非構造格子と境界適合格子を用いた解析モデルが多く用いられているが,格子生成に多大なコストがかかるため,ボクセル格子法の適用が検討されている.本研究では鼻腔の温度調節機能に着目し,医療画像より再構築したボクセル格子モデルを用いて鼻腔内流れの熱流体解析を行った..
68. Yuki Morimoto, Kenji Ono, 9D-11 バイオメカニズムのための強調的表現手法(OS-6 バイオシミュレーションに向けたイメージベースドモデリングの新展開(2)), バイオエンジニアリング講演会講演論文集, 2010, 23, 373-374, 2011.01.
69. 木村 真也, 田中 学, 三代 大樹, Toshihiro Sera, 覚正 信徳, 横田秀夫 , Kenji Ono, 高木 周, 9D-14 ボクセル格子法による鼻腔内熱流体解析(OS-6 バイオシミュレーションに向けたイメージベースドモデリングの新展開(3)), バイオエンジニアリング講演会講演論文集, 2010, 23, 515-516, 2011.01.
70. 淺野 秀夫, 伊藤 裕一, 大島 伸行, Kenji Ono, 鬼頭 幸三, 郡 逸平, 小山 隆太郎, 嶋田 喜芳, 堀之内 成明, 森吉 泰生, CFD技術の現状と今後の動向, 自動車技術, 65, 1, 90-96, 2011.01.
71. Kohei Okita, Kenji Ono, Shu Takagi, Yoichiro Matsumoto, Development of high intensity focused ultrasound simulator for large-scale computing, International Journal for Numerical Methods in Fluids, 10.1002/fld.2470, 65, 1-3, 43-66, 2011.01, [URL], 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..
72. 伊東 聰, 後藤 和哉, Kenji Ono, 領域分割法におけるサブドメインのノード内最適自動マッピング, ハイパフォーマンスコンピューティングと計算科学シンポジウム論文集, 2011, 163-169, 2011.01.
73. 橋本 学, Kenji Ono, FSI問題のためのAMRを用いたEulerianメッシュベーススキーム, 理論応用力学講演会 講演論文集, 10.11345/japannctam.59.0.52.0, 59, 0, 52-52, 2011.01, [URL], We have proposed an Eulerian mesh-based scheme using the level set function to analyze large-deformation fluid-structure interaction (FSI) problems. In this scheme, we introduce an interface treatment technique using virtual particles with the level sets and structural velocity components in order to enforce the kinematic condition at the interface on a fluid fixed mesh. In this study, we address problems where the boundary layer is relatively thin, such as coupled problems of external flow and a submerged elastic structure, for which it is necessary to consider adaptive mesh refinement (AMR) near the fluid-structure interface. We show the algebraic performance and numerical results compared with the ALE (Arbitrary Lagrangian-Eulerian) mesh-based scheme..
74. Kohei Okita, Kenji Ono, Shu Takagi, Yoichiro Matsumoto, Numerical simulation of the tissue ablation in high-intensity focused ultrasound therapy with array transducer, International Journal for Numerical Methods in Fluids, 10.1002/fld.2467, 64, 10-12, 1395-1411, 2010.11, 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..
75. 小川 孝法, Kenji Ono, 加藤 千幸, 藤澤 智光, 山田 貴博, 中島 研吾, スパコンは本当にものづくりに役立つのか?, 計算工学, 15, 4, 2435-2444, 2010.10.
76. 赤坂 啓, Kenji Ono, 非水密なポリゴン要素で構成された任意形状周りの直交格子を用いた非圧縮粘性流れ解析(流体工学,流体機械), Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 10.1299/kikaib.76.764_536, 76, 764, 536-545, 2010.09, [URL], 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 non-watertight 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 (Re=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..
77. Kenji Ono, 向井 亨光, 佐藤 吉将, メモリ効率の良いデータ構造を用いたロバストなボクセル化アルゴリズム, 計算工学講演会論文集, 15, 2, 785-788, 2010.05.
78. 橋本 学, Kenji Ono, レベルセット関数を用いたpartitioned coupling algorithmのfolded airbag deploymentへの適用, 計算工学講演会論文集, 15, 1, 231-234, 2010.05.
79. 木村 真也, 坂田 拓也, 田中 学, Toshihiro Sera, 覚正 信徳, 横田 秀夫, Kenji Ono, 高木 周, 鼻腔内気流のボクセルシミュレーション, 日本伝熱シンポジウム講演論文集, 10.11368/nhts.2010.0.89.0, 2010, 0, 89-89, 2010.05, [URL], 近年,CTやMRIなどの医療画像から鼻腔の3次元実形状を再構築し,嗅覚機能,温度や湿度の調節機能,異物除去フィルター機能などに関連して,鼻腔内流れのCFD解析が行われている.しかしながら従来の解析モデルでは非構造格子および境界適合格子で構成されることが多く,格子生成に高度なノウハウと多大な労力と時間を必要としている.このような格子生成のコストを解決する方法としてボクセル格子法の適用が検討されている.本研究では医療画像より再構築した鼻腔のボクセル格子モデルを用いて気流シミュレーションを行った..
80. Kei Akasaka, Kenji Ono, Simulation of incompressible viscous flow on cartesian grid for arbitrary geometries composed of non-watertight polygon elements, Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 76, 764, 536-545, 2010.04, 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..
81. 坂田 拓也, 田中 学, Toshihiro Sera, 覚正 信徳, 横田 秀夫, Kenji Ono, 高木 周, 0415 鼻腔内気流のボクセルシミュレーション(OS3-1:肺・気道のバイオエンジニアリング1), バイオエンジニアリング講演会講演論文集, 2009, 22, 67, 2010.01.
82. Kohei Okita, Kazuyasu Sugiyama, Kenji Ono, Shu Takagi, Yoichiro Matsumoto, Numerical study on high intensity focused ultrasound therapy using array transducer, Physics Procedia, 10.1016/j.phpro.2010.01.042, 3, 1, 315-322, 2010.01, [URL], 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..
83. Gaku Hashimoto, Kenji Ono, Interface Treatment under No-Slip Conditions Using Level- Set Virtual Particles for Fluid-Structure Interaction, Theoretical and Applied Mechanics Japan, 10.11345/nctam.58.325, 58, 0, 325-342, 2010.01, [URL], 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..
84. 伊東 聰, Kenji Ono, 503 SPHEREを用いた並列FEMコード開発(OS5.大規模並列・連成解析と関連話題(1),オーガナイズドセッション), 計算力学講演会講演論文集, 2009, 22, 70-71, 2009.10.
85. 橋本 学, Kenji Ono, 515 外側の空気の影響を考慮したエアバック展開シミュレーション(OS5.大規模並列・連成解析と関連話題(4),オーガナイズドセッション), 計算力学講演会講演論文集, 2009, 22, 93-94, 2009.10.
86. Kenji Ono, 次世代スパコン向け超大規模データの可視化手法, 計算工学, 14, 4, 2177-2178, 2009.10.
87. 坂田 拓也, 田中 学, Toshihiro Sera, 覚正 信徳, 横田 秀夫, Kenji Ono, 高木 周, S0203-1-2 鼻腔内気流の数値シミュレーション(上部気道の輸送現象), 年次大会講演論文集 : JSME annual meeting, 2009, 5, 55-56, 2009.09, Airflow patterns in the nasal cavity strongly affect the uptake and deposition of inhales pollutants, air-borne particles, and odorants over the entire nasal mucosa. Because of the nasal cavity's small size and structural complexity, the ability to accurately estimate the anatomically dependent airflow structures remains a challenge. In this study, the nasal cavity geometry was reconstructed from in vivo acquired CT data of the nasal passages in one healthy subject, and Voxel based CFD simulations were carried out for airflow in the nasal cavity model. In terms of the application to medical treatment, usefulness of these modeling techniques was discussed..
88. 沖田 浩平, Kenji Ono, 杉山 和靖, 高木 周, 松本 洋一郎, 組織の加熱凝固を考慮したHIFU治療シミュレーション
J0102-3-3 (次世代生命体統合シミュレーション(3)), 年次大会講演論文集 : JSME annual meeting, 2009, 6, 43-44, 2009.09, The development of High Intensity Focused Ultrasound (HIFU) therapy for the treatment of deeply-placed tumor has been desired. Problems are the displacement of focal point due to the reflection and refraction of ultrasound at the interfaces of bones and the attenuation of ultrasound due to the skins, fat and tissues. To minimize the invasive region of tissues by HIFU, the numerical simulation is available for the prediction of the treatment of tissues. In the present study, the HIFU therapy for the liver tumor is represented numerically. The simulation with the heat coagulation shows that the increase of acoustic impedance due to the coagulation causes the scattering of ultrasound at the interface of the coagulation region, which then develops toward the transducer. Therefore, the influence of the heat coagulation of tissue on the acoustic field should be considered to predict the treatment region precisely..
89. 伊東 聰, Kenji Ono, 次世代計算機用アプリケーション・ミドルウェアの開発, 計算工学講演会論文集, 14, 1, 59-62, 2009.05.
90. Kenji Ono, S202 ボリュームベースの流体解析システムの進展(生体に対する統合シミュレーションに向けて,SP2:シンポジウム2), バイオエンジニアリング講演会講演論文集, 2008, 21, 339-340, 2009.01.
91. Kenjiro Shimano, Takahiro Kumano, Michitoshi Takagi, Kenji Ono, Nariaki Horinouchi, Seiji Tarumi, Wind Tunnel Testing of JSAE Standard Low-aerodynamic-drag Vehicle Body Using 1/5 Scale Model, JSAE Review, 30, 1, 51-60, 2009.01.
92. 橋本 学, Kenji Ono, FSI問題のためのレベルセット仮想粒子による滑り無し条件を考慮した界面処理, 理論応用力学講演会 講演論文集, 10.11345/japannctam.58.0.197.0, 58, 0, 197-197, 2009, [URL], We have proposed a fluid-structure coupling approach based on fixed mesh using the level set function to analyze FSI (Fluid-Structure Interaction) problems of compressible inviscid flow and large-deformable thin shell. In this approach, we introduce interface treatment using virtual particles with the level sets and structural normal velocities in order to enforce the continuity of normal velocity at the interface on a fluid fixed mesh. In this study, it is shown that the present method is also applicable to FSI problems of incompressible viscous fluid and thin shell. Then the virtual particles also possess the structural tangent velocities to impose no-slip condition at the interface. We deal with FSI problems with finite deformation and compare the numerical results of the present method and the ALE (Arbitrary Lagrangian-Eulerian) moving mesh based scheme quantitatively..
93. Jorji Nonaka, Kenji Ono, Hideo Miyachi, Performance Evaluation of Large-Scale Parallel Image Compositing on a T2K Open Supercomputer, Information and Media Technologies, 10.11185/imt.4.780, 4, 4, 780-788, 2009, [URL], 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..
94. Jorji Nonaka, Kenji Ono, Hideo Miyachi, Performance Evaluation of Large-Scale Parallel Image Compositing on a T2K Open Supercomputer, IPSJ Online Transactions, 10.2197/ipsjtrans.2.140, 2, 140-148, 2009, [URL], 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..
95. Kenjiro Shimano, Takahiro Kumano, Michitoshi Takagi, Kenji Ono, Nariaki Horinouchi, Seiji Tarumi, Wind Tunnel Testing of JSAE Standard Low-aerodynamic-drag Vehicle Body Using 1/5 Scale Model, Review of Automotive Engineering, 10.11351/jsaereview.30.51, 30, 1, 51-60, 2009, [URL], 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..
96. Kenji Ono, ボリュームデータを用いたシームレスな流体シミュレーション環境, 理論応用力学講演会 講演論文集, 10.11345/japannctam.58.0.12.0, 58, 0, 12-12, 2009, [URL], An efficient environment for design process, which combines advanced scientific simulators and informationtechnology, was proposed for skilled manufacturing field. The proposed system is based on a volume data asshape modeling, which can fully eliminate time-consuming preprocess for CFD. Simulator codes areconstructed on modern object-oriented middleware V-Sphere. This framework provides functions such asunified user interface, maintenance performance, and development efficiency..
97. 橋本 学, Kenji Ono, 野口 裕久, 842 レベルセット関数を利用したエアバッグ展開シミュレーション(OS7.大規模並列・連成解析と関連話題(1),オーガナイズドセッション), 計算力学講演会講演論文集, 2008, 21, 880-881, 2008.11.
98. Kenji Ono, F1-3 生命体ソフトウェア開発と可視化の環境について(F-1 次世代生命体統合シミュレーション,フォーラム), 計算力学講演会講演論文集, 2008, 21, 5-6, 2008.11.
99. 沖田 浩平, 杉山 和靖, Kenji Ono, 高木 周, 松本 洋一郎, F1-7 強力集束超音波による低侵襲治療のシミュレーション(F-1 次世代生命体統合シミュレーション,フォーラム), 計算力学講演会講演論文集, 2008, 21, 13-14, 2008.11.
100. 伊東 聰, Kenji Ono, F1-9 ライフサイエンスシミュレーションを支えるミドルウェア(F-1 次世代生命体統合シミュレーション,フォーラム), 計算力学講演会講演論文集, 2008, 21, 17-18, 2008.11.
101. 岩田 正子, Kenji Ono, 玉木 剛, pFTT-AMRによる円柱回りの流れ(数値計算(1),一般講演), 日本流体力学会年会講演論文集, 2008, 77, 2008.09, This paper describes a simulation of octree with AMR using Fully Threaded Tree with Pedigree (pFTT) data structure that is most suitable for adaptive mesh strategy amongst standard, FTT and pFTT data structure. To validate the present approach, a simulation of the flow around a heated cylinder was performed on pFTT using AMR with temperature gradient as an index for refinement and un-refinement of cells. In the cylinder wake the finest cells were generated and moved along with the advection of Karman vortices..
102. 赤坂 啓, Kenji Ono, 直交格子を用いた薄い物体周りの非圧縮流れ計算の検討(数値計算(1),一般講演), 日本流体力学会年会講演論文集, 2008, 78, 2008.09, An incompressible flow solver on a Cartesian grid system was developed. This method can simulate the flow around an object of arbitrary shape on a Cartesian grid. The proposed method adopts a simple approach, which only requires the distance between the object surface and the closest cell center. Therefore this method is easy to implement and practical because the flow around a non-watertight geometry can be simulated without repairing the surface mesh of the geometry. In order to evaluate the effectiveness of this method, the flow around an object thinner than the mesh size and the flow around a circular cylinder (Reynolds number is ranging from 40 to 3000) were calculated. Consequently, it was found that the proposed method is robust and useful approach for practical problems..
103. 渡邉 大介, Kenji Ono, 茅 暁陽, 視線に基づく関心領域の特定と流れの可視化への適用, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 28, 1, 301-304, 2008.07.
104. 橋本 学, Kenji Ono, 野口 裕久, レベルセット関数を利用した高速流と大変形するシェルの連成解析, 計算工学講演会論文集, 13, 1, 17-18, 2008.05.
105. 柿本 正憲, 西沢 直樹, 芳賀 剛士, Kenji Ono, 大規模ボリュームデータの out of core 線画レンダリング, 計算工学講演会論文集, 13, 2, 593-596, 2008.05.
106. Kenji Ono, 橋本 学, 熱流体・構造連成解析システムの開発と自動車技術への応用, 自動車技術, 62, 5, 47-52, 2008.05.
107. 沖田 浩平, Kenji Ono, 高木 周, 松本 洋一郎, 高密度焦点式超音波療法の支援に向けたシミュレーション, 計算工学講演会論文集, 13, 2, 609-612, 2008.05.
108. 橋本 学, Kenji Ono, 野口 裕久, 大変形FSI解析のためのレベルセット粒子による界面処理, 理論応用力学講演会 講演論文集, 10.11345/japannctam.57.0.286.0, 57, 0, 286-286, 2008, [URL], ALE (Arbitrary Lagrangian-Eulerian) moving mesh based schemes are the most frequently used as fluid-structure coupling approaches. However the ALE based methods are not suitable for tracking interfaces with large deformation and movement. In this study, an Eulerian fixed mesh with the level set function is adopted. A novel interface treatment using virtual particles with the level set function is proposed to treat kinematical condition at the interface. A partitioned strong coupling algorithm is constructed in order to combine the level set particle interface treatment and advanced fluid and structure solvers, i.e. CIP (Constrained Interpolation Profile) -FEM for fluid and MITC (Mixed Interpolated Tensorial Components) shell elements for structure. The interface treatment capacity is evaluated and an expanding airbag is analyzed..
109. 橋本 学, Kenji Ono, 野口 裕久, G1305 レベルセット関数を利用した流体構造連成解析における界面の扱いに対する検討(2)(GS13 数値シミュレーション,一般セッション), 流体工学部門講演会講演論文集, 2007, "G1305-1"-"G1305-4", 2007.11, A fluid-structure coupling approach based on level set function is proposed in order to solve large deformation problems that are difficult to interface tracking method, such as ALE (Arbitrary Lagrangian-Eulerian) method. The fluid flow field is solved by using fixed mesh because the level set function can describe a complicated geometrical shape in analysis grids easily. In this study, kinematrical condition treatment with virtual particles is introduced at the fluid-structure interface and iterative computation based on a partitoned solution method is implemented..
110. 橋本 学, Kenji Ono, 野口 裕久, G1305 レベルセット関数を利用した流体構造連成解析における界面の扱いに対する検討(1)(GS13 数値シミュレーション,一般セッション), 流体工学部門講演会講演論文集, 2007, "G1305-a", 2007.11.
111. 渡邉 大介, Kenji Ono, 茅 暁陽, 視線情報を利用した3次元流れ場における関心領域の取得と流線の自動配置, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 27, 2, 119-120, 2007.09.
112. 岩田 正子, Kenji Ono, 玉木 剛, pFTTデータ構造を用いたAMRシミュレーション, 計算工学講演会論文集, 12, 2, 541-544, 2007.05.
113. Kenji Ono, 玉木 剛, 野田 茂穂, 岩田 正子, 重谷 隆之, オブジェクト指向並列化クラスライブラリの開発と性能評価, 情報処理学会論文誌コンピューティングシステム(ACS), 48, 8, 44-53, 2007.05, An Object-Oriented framework and class libraries with parallelism are designed and developed to enhance the construction of parallel physical simulators, which adopt domain decomposition method. Developed parallel data class is a class library that integrates a data structure and functions to manipulate the arrays for parallelisation. This data class can be used in both C/C++ and Fortran language. A benchmark code, which abstracts the part of a Jacobi iteration method for the elliptic partial differential equation, was ported using present framework and parallelized in C++/f90 mixed language. Measured timing results on Linux cluster showed us that the ported benchmark code using functions of the framework has almost the same performance and scalability of the original MPI benchmark code..
114. 沖田 浩平, Kenji Ono, 4101 医療用超音波発振装置の設計支援アプリケーションの開発(OS12 流体シミュレーションの医療技術への展開), 埼玉ブロック大会(講演会)講演論文集, 2007, 3, 97-98, 2007, 前立腺癌や乳癌の治療に用いられる高密度焦点式超音波療法を肝臓癌や脳腫瘍等の深部の治療に用いる際,超音波の反射・屈折による焦点位置のずれが問題となっている.本講演では,超音波発振装置のCADデータから生成される符号付き距離関数を直交格子系における形状表現に利用した超音波伝播アプリケーションと,環状アレイ型超音波発振装置の位相遅延による焦点位置および音圧の変化を解析した結果について報告する..
115. 橋本学 , Kenji Ono, 野口 裕久, レベルセット関数を利用した Partitioned Solution Method による流体構造連成解析, 計算力学講演会講演論文集, 683-684, 2007.
116. 岩田 正子, Kenji Ono, 玉木 剛, 2125 pFTTデータ構造を用いたオクツリー解適合格子によるシミュレーション(G01-3 計算力学(3),GO1 計算力学), 年次大会講演論文集 : JSME annual meeting, 2006, 1, 75-76, 2006.09, This paper describes a simulation of octree AMR using Fully Threaded Tree with Pedigree (pFTT) data structure that is most suitable for adaptive mesh strategy among standard, FTT and pFTT data structures. To validate the present approach, a scalar transport equation was calculated on pFTT, using AMR with scalar gradient as an index for joining and splitting cells. According to numerical experiments, it was found that this method was able to capture a face of discontinuity appropriately. Skipping the process of joining and splitting, however, leads to the decline of the numerical accuracy and the increase of the calculation costs. Reasonably good results were obtained with every or every 2 steps joining and splitting on pFTT using AMR..
117. 赤坂 啓, Kenji Ono, 2218 ボクセル法を用いた非圧縮流れ解析の境界条件の実装方法(G05-3 解析モデルと解析手法,G05 流体工学), 年次大会講演論文集 : JSME annual meeting, 2006, 2, 9-10, 2006.09, Voxel based simulation is very convenient at the early stages of a product design because the simple block approximation of a shape can realize automatic and robust mesh generation. However, the voxel method is not capable of simulating the characteristics of flow and expressing the detail shapes less than the voxel size. Therefore, the relationship based on an experimental data, which reflects the flow characteristics, is often incorporated into the simulation as boundary conditions. For accurate flow simulation in an engine bay, the satic pressure drop caused by heat exchanger should be taken into account in governing equations. In this paper, the modeling of pressure loss at the heat exchanger on the voxel method is proposed. Incompressible flow around a heat exchanger was calculated using the present method as verification. It was found that the proposed method could accurately predict the pressure drop and flow field..
118. 加藤 光章, 吉澤 晋, Kenji Ono, 松本 洋一郎, 3638 集束超音波医療における温度上昇の数値解析(G05-4 流体機械・医療機器,G05 流体工学), 年次大会講演論文集 : JSME annual meeting, 2006, 2, 369-370, 2006.09, Focused ultrasound treatment is widely applied in the clinical treatment, for example the tumor ablation with High Intensity Focused Ultrasound (HIFU). HIFU shows considerable nonlinearity due to its high pressure amplitude, and it is attenuated, reflected and refracted in the medium. Previously, researchers have simulated the ultrasound field using linear and nonlinear approximation equations. However, the predictions using these equations have restrictions such that the higher order nonlinearity or the reflection and refraction cannot be reproduced. So we apply axsymmetric Navier-Stokes equation to the governing equation to solve the ultrasound propagation without such restrictions. We calculated the profile of temperature rise in a liver with the model of an array transducer and an absorption effect. It is concluded that the temperature rise is focused at focal point by modeling array transducer and the ratio of the parameters inside the absorption coefficient affects the temperature rise and distribution..
119. Kenji Ono, 宮地 英生, 先進可視化システムとその活用, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.26.Supplement1_39, 26, 1, 39, 2006.07, [URL], This panel discussion intends to find hints for a visualization system of the next generation. The Panelists are invited from major research centers that are performing large-scale simulation and visualization. The computer hardware is upgrading its performance every quarter and enables us to calculate more large-scale grid points as we can find in the TOP500 list. On the other hand, a few visualization system can currently deal with the huge amount of data that is generated by tera-scale computing. In addition, since the almost large-scale computation will be conducted on distributed parallel environment, the visualization system will be so much more complicated.
Open discussion will be expected to share issues and to derive useful knowledge for the visualization system of the next generation..
120. Kenji Ono, 玉木 剛, SPHERE
シミュレーションの開発・実行支援環境, 電気学会研究会資料. SA, 静止器研究会, 2006, 1, 73-78, 2006.01.
121. 榎本 秀喜, Kenji Ono, 125 微小圧縮性による流体音の解析(計測・解析II), 日本機械学会関東支部ブロック合同講演会講演論文集, 2006, 147-148, 2006.
122. Kenji Ono, SPHERE : : 物理シミュレーションプログラム開発のフレームワーク, 計算工学, 10, 4, 1227-1232, 2005.10.
123. Kenji Ono, 玉木 剛, 606 SPHERE
物理シミュレーションと工学研究のためのスケルトンシステム(J02-2 解析・設計の高度化・最適化(2),J02 解析・設計の高度化・最適化), 年次大会講演論文集 : JSME annual meeting, 2005, 6, 39-40, 2005.09, This paper describes concept and implementation of a novel simulation framework for various physical simulations. The framework, which is called SPHERE, is a kind of application framework to realize the unified software structure. SPHERE allows us to write program more efficient and to use the application easy. Besides, the framework is working on several major platforms with standard libraries. Thus, this system will provide a productive environment for physical simulation code developpers..
124. 岩田 正子, Kenji Ono, 玉木 剛, 629 オクツリー格子を用いたシミュレーションのデータ構造比較(S09 直交適合格子による計算手法), 年次大会講演論文集 : JSME annual meeting, 2005, 1, 83-84, 2005.09, This paper describes the comparison of octree data structure intending to find a suitable one for the simulation with a solution adaptive octree mesh. We compared three different kind of implementation of octree, such as Standard, FTT and Pedigree FTT that we proposed, performing simulation programs of a steady-state heat transfer problem. It was found that Pedigree FTT appeared to be most suitable among them from the view points of memory utilization and calculation cost..
125. Kenji Ono, F04-(2) ビジュアルデータマイニング支援によるPSEの構築(可視化からビジュアルデータマイニングヘ,先端技術フォーラム), 年次大会講演資料集, 2005, 8, 147-148, 2005.09.
126. Kenji Ono, 吉川 広幸, 俵 展丈, 次世代可視化システムのプラットホーム, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 25, 1, 249-250, 2005.03.
127. 渡辺 大介, 茅 暁陽, Kenji Ono, 金 小鋼, 視線情報に基づく流れの可視化システム, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.25.Supplement1_255, 25, 1, 255-258, 2005.03, [URL], With the advance of high performance computing and modern numerical simulation technology, flow fields obtained from the simulation are becoming more and more large and complex. It is an extremely challenging problem to display a large flow field in the limited 2D space on a computer screen. In this paper, we present a system that adapts display resources to user intentions by using eye-tracking data. When observing a flow field, users usually gaze at some particular regions, such as around a critical point, the boundary of an object, and selectively follow some important structure or interesting flow pattern. Since "viewing" is the most important user task in flow observation, we assume it is possible to predict users' intentions, either conscious or unconscious ones, by analyzing eye-tracking data. The proposed system employs a set of focus+context visualization techniques to effectively visualize the regions of interest, which are automatically predicted based on eye-tracking data..
128. Kenji Ono, 吉川 広幸, C219 マルチプラットホーム可視化APIの設計と開発, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.25.Supplement2_365, 25, 2, 365-366, 2005, [URL], This paper reports a newly designed visualization API (Application programming Interface) for a Cartesian and octree data structure which allows us. to render and visualize the data efficiently. It is designed that this visualization API is consists of a window frame class, a scene-graph class and a visualization function class. The window frame class is constructed from wxWidgets, which is open source GUI system, so as to be operated on major platforms such as Linux, Windows and MacOS X. As concerns the scene-graph class, we developed an original API instead of the standard sene-graph library like VTK because of seeking of the rendering efficiency and supporting the special data structure. Based on this API, a rendering application was developed and evaluated. This data viewer will be delivered from RIKEN..
129. Kenji Ono, 吉川 広幸, 俵 展丈, D209 次世代可視化システムのプラットホーム, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.25.Supplement1_249, 25, 1, 249-250, 2005, [URL], A new-designed framework for building a visualization system was proposed and developed. This framework enables us to extend a new function easily as a module. In addition, this framework and a sample application are operating on major platforms, such as MacOSX, Linux and Windows operation systems. Sample application shows several functions intended for actual design work. In particular, the function of multiple-on-screen windows provided by the framework is very useful, especially in combination with multiple results..
130. Kenji Ono, SPHERE
物理シミュレーションプログラム開発のフレームワーク (特集 CFD最新技術), 計算工学, 10, 4, 1227-1232, 2005.
131. Kenji Ono, 大竹 豊, 白崎 実, ボリュームデータを用いた流体解析システムの可能性(ボリュームデータ,ボクセルデータなどに基づくものつくり支援システム), シミュレーション, 23, 4, 286-291, 2004.12, An urgent problem of Computational Fluid Dynamics (CFD) system from the viewpoint of users is a treatment of complex geometries that we must face in the real world It is also recognized that care for the operation of CFD system for actual design process of products is an underlying issue To overcome these issues, a newly Cartesian based CFD system, which combines volume data, was proposed The combination between shape expression by implicit function, an octree data structure and several kinds of shape capturing schemes provides the flexibility of the shape approximation for users Thus, the users will be able to control the balance of prediction accuracy and computation time In addition, a class library of C++, which has a unified user-interface, is constructed for the solver development in order to increase userfnendhness and efficiency of the solver development.
132. 今北 暁夫, Kenji Ono, 吉澤 晋, 松本 洋一郎, 生体内における超音波伝播挙動の数値解析(OS9-2生物流体工学とその応用(循環器系の血流解析)), 流体工学部門講演会講演論文集, 2004, 277, 2004.11.
133. Kenji Ono, 玉木 剛, 重畳装置を用いたインタラクティブボリュームレンダリングの性能評価(OS22b CGと計算力学), 計算力学講演会講演論文集, 2004, 17, 437-438, 2004.11.
134. 林 幸子, 宮地 英生, Kenji Ono, 画像重畳装置とクラスタ装置を使った高速可視化システムの開発, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.24.Supplement1_299, 24, 1, 299-302, 2004.07, [URL], A novel software "AVS/Express PCE", which runs on commodity-based PC cluster, was developed to visualize a large-scale data set efficiently. This system allows users to customize functions without any parallel knowledge and provides parallelized processes for almost all of processes such as I/O, filtering, mapping, and rendering. It is very effective to parallelize all processes but the image compositing becomes a bottleneck for a parallel rendering system. To avoid this problem, a special hardware that can synthesize an output image from input images without significant delay was combined to the software. According to preliminary test results, the present system performed about 4 frames per second to update iso-surfaces for a million grids field data..
135. Kenji Ono, 玉木 剛, 吉川 広幸, 片野 康生, Kwan-Liu Ma, 非定常大規模データのインタラクティブ可視化システムの開発, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 24, 1, 311-314, 2004.07.
136. Kenji Ono, CFDの深みにはまった経験, Turbomachinery International, 10.11458/tsj.32.263, 32, 5, 263-266, 2004.05, [URL].
137. Kenji Ono, Role of Fluid Dynamics Technology in Automobile Design, Review of Automotive Engineering, 25, 2, 129-134, 2004.04.
138. Kenji Ono, 玉木 剛, 吉川 広幸, 片野 康生, Kwan-Liu Ma, D205 非定常大規模データのインタラクティブ可視化システムの開発, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.24.Supplement1_311, 24, 1, 311-314, 2004, [URL], A parallel volume rendering system that incorporated a hardware compositor was developed to visualize unsteady large-scale data set in real-time. This rendering system is constructed by PC-cluster on a master-slave basis, and utilizes hardware functions of GPU on a modern graphics card. At first, a master node divides a data region into several sub-domains, and then each slave node renders the images for each domain. Generated images on each Slave-PC are gathered and overlapped each other according to a BSP tree, which is determined by the relation between an eye point and the position of each domain. This superimpose process is carried out on a composite hardware to minimize the transmission and synthesis time of the images. It was found that the present visualization system achieved enough interactivity with 10-15 fps for time varying data of 25.6GB..
139. Gabriel G. Rosa, Eric B. Lum, Kwan Liu Ma, Kenji Ono, An interactive volume visualization system for transient flow analysis, 2003 Eurographics/IEEE TVCG Workshop on Volume Graphics, VG '03
Proceedings of the 2003 Eurographics/IEEE TVCG Workshop on Volume Graphics, VG '03
, 10.1145/827051.827072, 45, 2003.12, [URL], 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..
140. Kenji Ono, Kwan Liu Ma, 104 設計利用のためのインタラクティブボリュームレンダリングシステムの開発, 計算力学講演会講演論文集, 2003, 16, 11-12, 2003.11, This paper describes the design and performance of an interactive visualization system developed specifically for time-varying volume data from thermal flow simulations. The system uses compression to allows for better memory utilization and faster data transfer, hardware accelerated rendering to enable interactive exploration for parameters and fluid phonomenon, and an intuitive user interface to support comparative visualization. It was found that this system have enough capabilities for interactive visualization. Especially, the latest commodity hardware will accelerrate the perfomance of this system..
141. Kenji Ono, 646 設計支援のためのロバストな流体解析システム, 計算力学講演会講演論文集, 2003, 16, 571-572, 2003.11, This paper describes the implementation of various boundary conditions using simple immersed boundary method originally proposed by Peskin. The direct forcing technique, extended by Fadlun, is used for the caliculation of the external force in Navier-Stokes equations and has the capability of representation not only for walls but also various types of boundaries. Avoiding the intepolation to achive higher approximation of shape, the present method has a very robust feature. Two examples are demonstrated in this paper, one is flow around a circular cylinder and the other is flow induced by a fan..
142. Kenji Ono, 自動車設計における空力音予測の研究動向, 騒音制御, 10.11372/souonseigyo1977.27.318, 27, 5, 318-323, 2003.10, [URL].
143. Kenji Ono, 212 複雑形状を扱うボクセル法における圧力境界条件のポアソン方程式への実装方法, 年次大会講演論文集 : JSME annual meeting, 2003, 1, 13-14, 2003.08, Cartesian grid method has higher availability for actual problems of design as First Order Analysis. Especially, simple block approximation is of great stability at the grid generation stage. In this case, arbitrary patterns of wall appear in the computational domain where adequate pressure boundary condition should be employed. In this paper, an implementation of boundary condition that is build into the discretized scheme of pressure Poisson equation is proposed. This method eliminates the difficulties such as the reference points that have multiple value of pressure effectively..
144. Kenji Ono, CFDの新展開  設計における直交格子法の利用, ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 10.11426/nagare1982.21.16, 21, 1, 16-25, 2002.03, [URL].
145. Kenji Ono, 設計における直交格子法の利用(CFDの新展開), ながれ : 日本流体力学会誌 = Journal of Japan Society of Fluid Mechanics, 21, 1, 16-25, 2002.02.
146. Kenji Ono, C234 自動車設計への適用を考慮したロバストな流体解析手法, 日本流体力学会年会講演論文集, 2001, 281-282, 2001.07, It was discussed that how to apply the flow simulation to a vehicle designs in order to enhance the efficiency of the vehicle development on a digital process, which is emerging recently at almost automotive companies in the world. As the result of the discussion, it was derived that the requirements for the flow simulation at the early stage of the vehicle development. One of the most important factors for the flow analysis is the turnaround time of the simulation as well as the accuracy of the computation. From the standpoint of these situations, the Cartesian mesh method becomes the most powerful tool among various analysis methods. In this paper, the Cartesian method was classified by means of the level of shape approximation and each feature was reviewed briefly..
147. 古尾谷 信吾, 浦 智紀, 池田 雅文, Kenji Ono, エアクリーナ雪入り予測手法の開発, 自動車技術, 54, 12, 61-63, 2000.12.
148. Kenji Ono, WS5-4 自動車の空力騒音解析, 流体工学部門講演会講演論文集, 2000, 324-327, 2000.09, Wind noise radiated from the side-window and the door mirror mounted on a vehicle was computed using Lighthill's acoustic analogy. The flow fields were calculated by the well established finite-difference method with an overlapped grid technique. Computed pressure fluctuation on the door mirror surface was compared with the measured one. It was found that the pressure fluctuation as the noise source was predicted with good accuracy. Then, the shape modification to reduce the wind noise was performed based on the visualized surface streamline and noise sources. Consequently, it was confirmed that the wind noise was reduced..
149. Kenji Ono, 姫野 龍太郎, 解説 自動車設計に関わる流体問題と日産自動車における空力分野のCFDについて, 数値流体力学, 8, 4, 167-179,190, 2000.07.
150. Kenji Ono, Ryutaro Himeno, Tatsuya Fukushima, Prediction of wind noise radiated from passenger cars and its evaluation based on auralization, Journal of Industrial Aerodynamics, 81, 403-419, 1999.05, 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..
151. Kenji Ono, K. Fujitani, H. Fujita, Applications of CFD using voxel modeling to vehicle development, Proceedings of the 1999 3rd ASME/JSME Joint Fluids Engineering Conference, FEDSM'99, San Francisco, California, USA, 18-23 July 1999 (CD-ROM), 1, 1999, 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..
152. Kenji Ono, Ryutaro Himeno, Sanae Sato, Naoshi Kikuchi, Visualization of a Flow around a Circular Cylinder with Spiral Grooves Using CFD, Album of visualization, 13, 17-18, 1996.12.
153. 姫野 龍太郎, 福島 達也, Kenji Ono, CFDによる車用ミラーの空力騒音の合成と流れの可視化, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 16, 87-90, 1996.07.
154. Kenji Ono, 姫野 龍太郎, 冨田 直幸, 藤谷 克郎, マルチレベル直交格子を用いた三次元非定常非圧縮性流体の解析, 日本流体力学会年会講演論文集, 15, 243-244, 1996.07.
155. Kenji Ono, 姫野 龍太郎, 塩澤 博行, 佐藤 早苗, 車体外部の微小な形状変化が流れ場に及ぼす影響について, 計算工学講演会論文集, 1, 1, 475-478, 1996.05.
156. 姫野 龍太郎, 福島 達也, Kenji Ono, 110 CFDによる車用ミラーの空力騒音の合成と流れの可視化, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.16.1Supplement_87, 16, 1, 87-90, 1996, [URL], Unsteady flows around a door mirror mounted on a passenger car were computed using a third-order upwind-difference scheme and an overset grid technique. Aerodynamic noises in far field, emitted from the mirror, were calculated from pressure fluctuation on the surface using Curle's equation. They were synthesized by an Apple Macintosh.
Flow were separately visualized on a graphic workstation. Rendered images were transferred to the Macintosh. Those images and the synthesized sounds were edited into a video tape. We could evaluate the aerodynamic noise by our own ears without any physical model and investigate the relationship between flows and sounds in detail..
157. Ryutaro Himeno, Tatsuya Fukushima, Kenji Ono, Computation of aerodynamic noise emitted from a door mirror of a passenger car and its synthesis, American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED, 242, 167-173, 1996, 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..
158. 藤原 和人, 松尾 日出男, Kenji Ono, 広江 哲幸, くいちがい配置された2正方形柱まわりの流れ, 日本航空宇宙学会誌, 10.2322/jjsass1969.40.276, 40, 460, 276-284, 1992, [URL], Flow around two square cylinders is investigated by the measurement of the surface pressure, the flow visualization and the supplementary numerical simulation. Two different types of flow patterns are observed which are characteristic of staggered arrangements. In either case, the gap flow is formed between two cylinders, which is biased towards the upstream cylinder. The biased flow then undergoes two different changes in the subsequent period depending on the relative location of cylinders. In the first case it flows on straightforward and finally builds up a strong vortex behind the upstream cylinder. In the second case it changes the direction and deviates towards the downstream cylinder. A strong vortex is now built up behind the downstream cylinder. However, the second flow is not stable and can not exist by itself. The fluctuation between the first and the second flows always appears in this case. The transition between the two flow regimes is abrupt under the continuous change in the cylinder arrangement..
159. Kenji Ono, 姫野 龍太郎, 藤谷 克郎, 佐藤 早苗, B113 三次元流れ解析による自動車の耐熱性能の検討, 可視化情報学会誌 = Journal of the Visualization Society of Japan, 10.3154/jvs.11.Supplement2_135, 11, 2, 135-138, 1991, [URL], Computational analysis was performed for the external flow around an automobile and the internal flow in the engine compartment using a multi-block grid system and a finite-difference method. Cooling performance of the radiator is evaluated by the flow quantity passing through the radiator. Computational results show quite good agreement with experimental data. Present method is applied to the design of an the inter-cooler, it shows that the cooling performance of the inter-cooler could be improve by changing the duct configuration..

九大関連コンテンツ

pure2017年10月2日から、「九州大学研究者情報」を補完するデータベースとして、Elsevier社の「Pure」による研究業績の公開を開始しました。