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Journal Articles

Development of contamination detection system combined with various remote devices

Morishita, Yuki; Miyamura, Hiroko; Sato, Yuki; Oura, Masatoshi*

Radiation Measurements, 171, p.107064_1 - 107064_7, 2024/02

The detection of alpha and beta contamination locations is important for decontaminating nuclear facilities. In the high radiation dose rate environment at the decommissioning sites, the contamination measurement by the workers is not effective. Thus, we developed a remote automatic contamination measurement system using a new scintillator-based detector. A 50 mm$$phi$$ $$times$$ 100-$$mu$$m-thick YAlO$$_{3}$$(Ce)(YAP:Ce) scintillator was coupled with a flat panel-type multianode photomultiplier tube. The detector was installed downwards at the bottom of a robot. It has an energy measurement capability, and the energy measurement could discriminate the alpha particles from the beta and $$^{222}$$Rn alpha particles. With the energy information, alpha and beta particles could be identified and mapped simultaneously. In addition, a slow-moving robot could be used to obtain statistically sufficient counts in a single run measurement, allowing the evaluation of surface contamination density using only alpha particles. The remote automatic contamination measurement system will be useful in visualizing the contamination distribution in environments that are inaccessible to workers.

Journal Articles

R&D of digital technology on inverse estimation of radioactive source distributions and related source countermeasures; R&D status of digital platform including 3D-ADRES-indoor

Machida, Masahiko; Yamada, Susumu; Kim, M.; Okumura, Masahiko; Miyamura, Hiroko; Shikaze, Yoshiaki; Sato, Tomoki*; Numata, Yoshiaki*; Tobita, Yasuhiro*; Yamaguchi, Takashi; et al.

RIST News, (69), p.2 - 18, 2023/09

The contamination of radioactive materials leaked from the reactor has resulted in numerous hot spots in the Fukushima Daiichi Nuclear Power Station (1F) building, posing obstacles to its decommissioning. In order to solve this problem, JAEA has conducted research and development of the digital technique for inverse estimation of radiation source distribution and countermeasures against the estimated source in virtual space for two years from 2021 based on the subsidy program "Project of Decommissioning and Contaminated Water Management" performed by the funds from the Ministry of Economy, Trade and Industry. In this article, we introduce the results of the project and the plan of the renewal project started in April 2023. For the former project, we report the derivative method for LASSO method considering the complex structure inside the building and the character of the source and show the result of the inverse estimation using the method in the real reactor building. Moreover, we explain the platform software "3D-ADRES-Indoor" which integrates these achievements. Finally, we introduce the plan of the latter project.

Journal Articles

LASSO reconstruction scheme to predict radioactive source distributions inside reactor building rooms; Practical applications

Machida, Masahiko; Shi, W.*; Yamada, Susumu; Miyamura, Hiroko; Yoshida, Toru*; Hasegawa, Yukihiro*; Okamoto, Koji; Aoki, Yuto; Ito, Rintaro; Yamaguchi, Takashi; et al.

Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 11 Pages, 2023/02

Journal Articles

Visual analysis of geospatial multivariate data for investigating radioactive deposition processes

Takahashi, Shigeo*; Sakurai, Daisuke*; Sasaki, Miyuki; Miyamura, Hiroko; Sanada, Yukihisa

Visual Computer, 37(12), p.3039 - 3050, 2021/12

 Times Cited Count:0 Percentile:0.01(Computer Science, Software Engineering)

The Fukushima nuclear accident in 2011 raised awareness on the importance of radioactive deposition processes, especially for proposing aerosol measures against possible air pollution. However, identifying these types of processes is often difficult due to complicated terrains. This paper presents an application study for identifying radioactive deposition processes by taking advantage of visual interaction with topographic data. The idea is to visually investigate the correspondence of the spatial positions to the air dose rate along with relevant attributes. This is accomplished by composing scatterplots of pairwise attributes, onto which we project terrain areas to interactively find specific patterns of such attributes. We applied our approach to the analysis of air dose rate distribution data around the Fukushima nuclear plant after the accident. Our visualization technique clearly distinguished contamination areas derived from different deposition processes, and thus is useful for elucidation of the deposition process.

Journal Articles

Image reconstruction of radioactive contamination due to the Fukushima-Daiichi Nuclear Power Station Accident using a compact Compton camera

Sato, Yuki; Terasaka, Yuta; Miyamura, Hiroko; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Torii, Tatsuo

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.428 - 436, 2018/11

 Times Cited Count:0 Percentile:0.05

Journal Articles

Remote radiation imaging system using a compact $$gamma$$-ray imager mounted on a multicopter drone

Sato, Yuki; Ozawa, Shingo*; Terasaka, Yuta; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Miyamura, Hiroko; Izumi, Ryo*; Suzuki, Toshikazu*; Torii, Tatsuo

Journal of Nuclear Science and Technology, 55(1), p.90 - 96, 2018/01

 Times Cited Count:41 Percentile:98.09(Nuclear Science & Technology)

Journal Articles

Development of compact Compton camera for 3D image reconstruction of radioactive contamination

Sato, Yuki; Terasaka, Yuta; Ozawa, Shingo*; Miyamura, Hiroko; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Torii, Tatsuo

Journal of Instrumentation (Internet), 12(11), p.C11007_1 - C11007_8, 2017/11

 Times Cited Count:17 Percentile:65.53(Instruments & Instrumentation)

Journal Articles

Radiation imaging system using a compact $$gamma$$-ray imager mounted on a remotely operated machine

Sato, Yuki; Kawabata, Kuniaki; Ozawa, Shingo*; Izumi, Ryo*; Kaburagi, Masaaki; Tanifuji, Yuta; Terasaka, Yuta; Miyamura, Hiroko; Kawamura, Takuma; Suzuki, Toshikazu*; et al.

IFAC-PapersOnLine, 50(1), p.1062 - 1066, 2017/07

 Times Cited Count:3 Percentile:66.55

Journal Articles

Algebraic design of multi-dimensional transfer function using transfer function synthesizer

Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi

Journal of Visualization, 20(1), p.151 - 162, 2017/02

 Times Cited Count:2 Percentile:18.42(Computer Science, Interdisciplinary Applications)

In this paper, we propose a novel transfer function design interface for multivariate volume rendering. In the conventional multivariate volume rendering, GUI based transfer function design interfaces were limited to two-dimensional variables space. In order to design higher dimensional transfer functions in an interactive and intuitive manner, a Transfer Function Synthesizer (TFS) is developed. On the TFS, multi-dimensional transfer functions are generated by algebraic synthesis of one-dimensional transfer functions, which are designed based on the conventional GUIs or algebraic expressions. The TFS enables not only multivariate volume rendering but also general visualization techniques such as surface visualization and image composition within the framework of volume rendering. The TFS is implemented on the remote visualization system PBVR, and applied to various multivariate scalar volume data generated from nuclear applications.

Journal Articles

Inferring partial orders of nodes for hierarchical network layout

Wu, H.-Y.*; Takahashi, Shigeo*; Miyamura, Hiroko; Ozahata, Satoshi*; Nakao, Akihiro*

Electronic Imaging, 2017(1), p.118 - 130, 2017/01

Extracting hierarchical structures from networks provides us with an effective means of visualizing them, especially when they contain complicated node connectivities such as those in traffic and distributed networks. This paper presents an algorithm for inferring such partial orders by optimizing the network hierarchies along flow paths that are given as input. We study several network examples to demonstrate the feasibility of the proposed approach including course dependency charts, railway networks, and P2P networks.

Journal Articles

Inferring partial orders of nodes for hierarchical network layout

Wu, H.-Y.*; Takahashi, Shigeo*; Miyamura, Hiroko; Ozahata, Satoshi*; Nakao, Akihiro*

Journal of Imaging Science and Technology, 60(6), p.060407_1 - 060407_13, 2016/11

 Times Cited Count:0 Percentile:0.02(Imaging Science & Photographic Technology)

Extracting hierarchical structures from networks provides us with an effective means of visualizing them, especially when they contain complicated node connectivities such as those in traffic and distributed networks. This paper presents an algorithm for inferring such partial orders by optimizing the network hierarchies along flow paths that are given as input. We study several network examples to demonstrate the feasibility of the proposed approach including course dependency charts, railway networks, and P2P networks.

Journal Articles

Level of detail control for environmental monitoring datasets

Miyamura, Hiroko; Takemiya, Hiroshi; Wu, H.-Y.*; Takahashi, Shigeo*

Kashika Joho Gakkai-Shi, 36(143), p.152 - 156, 2016/10

Broad survey on the distribution of the air dose rate has been performed after the accident at the Fukushima Daiichi Nuclear Power Plant continuously. The surveyed monitoring datasets are stored in a database and are made available to the public. Recently, the size of the datasets have been significantly increased as more detailed measurements in space and time are available, and effective reduction of the size of the datasets is necessary for visualizing and exploring such large scale datasets. However, if the datasets are not carefully reduced, we often miss a part of important features of the distribution data. Therefore, we develop an effective Level of Detail control (LoD) method for retaining critical features of the distribution. In the method, the global and local features of the distribution are extracted by means of differential topology analyses. Then, the simplified data is created by edge collapse operation with taking into account these features of the data.

Journal Articles

Visualization in response analyses for a nuclear power plant

Nakajima, Norihiro; Nishida, Akemi; Miyamura, Hiroko; Iigaki, Kazuhiko; Sawa, Kazuhiro

Kashika Joho Gakkai-Shi (USB Flash Drive), 36(Suppl.2), 4 Pages, 2016/10

Since nuclear power plants have dimensions approximately 100m$$^{3}$$ and their structures are an assembly made up of over 10 million components, it is not convenient to experimentally analyze its behavior under strong loads of earthquakes, due to the complexity and hugeness of plants. The proposed system performs numerical simulations to evaluate the behaviors of an assembly like a nuclear facility. The paper discusses how to carry out visual analysis for assembly such as nuclear power plants. In a result discussion, a numerical experiment was carried out with a numerical model of High Temperature engineering Test Reactor of Japan Atomic Energy Agency and its result was compared with observed data. A good corresponding among them was obtained as a structural analysis of an assembly by using visualization. As a conclusion, a visual analytics methodology for assembly is discussed.

Journal Articles

An Illustration by the next generation numerical simulator for quake-proofing on the K

Nakajima, Norihiro; Suzuki, Yoshio; Miyamura, Hiroko; Nishida, Akemi; Kawakami, Yoshiaki; Guo, Z.; Tomiyama, Eiji*

Keisan Kogaku, 20(4), p.3338 - 3340, 2015/12

The issue 5 in the field 4 of "Monodukuri" in the HPCI strategy project is introduced. The title of the issue 5 is "research and development for the next-generation earthquake-resistant simulation of the large plants such as nuclear energy facilities". The illustration intends for a high temperature engineering examination research reactor. Implementation of FIESTA (Finite Element Analysis for Structure of Assembly) on K is described by reporting its efficiency and performance. To show a result of the numerical analysis, a visualization technique for the big data was described.

Journal Articles

Analyses for designing objects in mechanical design

Nakajima, Norihiro; Miyamura, Hiroko; Kawakami, Yoshiaki; Kawamura, Takuma

Kashika Joho Gakkai-Shi, 35(Suppl.1), p.233 - 238, 2015/07

no abstracts in English

Journal Articles

Visualization technique for large-scale data by particle-based volume rendering

Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Imamura, Toshiyuki*; Takemiya, Hiroshi

Shisutemu Seigyo Joho Gakkai Rombunshi, 28(5), p.221 - 227, 2015/05

However remote volume visualization is important to obtain knowledge from complicated large-scale simulation results on supercomputer, the rendering speed and data transfer speed becomes bottleneck of the conventional Client/Server volume visualization techniques. Client/Server visualization system using particle-based volume rendering enables interactive volume visualization, which converts the original volume data to small size light particle data utilizing the supercomputer and transfer the data to Client PC. This system generated the particle data at a few seconds using parallel process on supercomputer Kei with strong scaling till 1000 processers.

Journal Articles

Remote visualization system based on particle based volume rendering

Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi; Sakamoto, Naohisa*; Koyamada, Koji*

Visualization and Data Analysis 2015 (Proceedings of SPIE Vol.9397) (Internet), p.93970S_1 - 93970S_8, 2015/02

 Times Cited Count:4 Percentile:87.65

In this paper, we propose a novel remote visualization system based on particle-based volume rendering (PBVR), which enables interactive analyses of extreme scale volume data located on remote computing systems. The remote PBVR system consists of Server, which generates particles for rendering, and Client, which processes volume rendering, and the particle data size becomes significantly smaller than the original volume data. Depending on network bandwidth, the level of detail of images is flexibly controlled to attain high frame rates. Server is highly parallelized on various parallel platforms with hybrid programing model. The mapping process is accelerated by two orders of magnitudes compared with a single CPU. The structured and unstructured volume data with 100 millions of cells is processed within a few seconds. Compared with commodity Client/Server visualization tools, the total processing cost is dramatically reduced by using proposed system.

Journal Articles

Multivariate volume rendering using transfer function synthesizer implemented in remote visualization system PBVR

Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi

Proceedings of SIGGRAPH Asia 2015 (SA 2015) (Internet), 4 Pages, 2015/00

In this paper, we propose a novel transfer function design technique for multivariate volume rendering. This technique generates a multidimensional transfer function by logical synthesis of variables and transfer functions. This technique enables analysts to extract correlation of variables and to combine multivariate surface and volume shapes. And this technique is implemented in Remote Visualization System PBVR optimized to several supercomputers. An experiment for the multi-phase fuel melting simulation result in the nuclear energy field shows the powerful ability of this technique enough by extracting complex behavior of molten materials.

Journal Articles

2-dimentional visualization technique for exploring region of interest in 4-dimensional data

Miyamura, Hiroko; Kawamura, Takuma; Suzuki, Yoshio; Idomura, Yasuhiro; Takemiya, Hiroshi

Joho Shori Gakkai Rombunshi, 55(9), p.2216 - 2224, 2014/09

In numerical simulations, variations of calculation results with respect to a variable axis are often observed. When the target model is given in 3D, the simulation results become 4D. Such a multi-dimensional dataset given in more than 4D space is analyzed by detailed explorations of regions of interest (ROIs) in multi-dimensional space. However, for high-dimensional and large-scale datasets, this approach requires enormous processing time and effort, and may have difficulty in capturing all the ROIs. Therefore, we propose a technique that is based on a concept of spatiotemporal image. In our technique, a space axis is created by octree, a variable axis is defined in the direction perpendicular to the space axis. Our technique is applied to the results of 3D seismic simulations of a nuclear plant, and regions with characteristic frequency responses of each region are analyzed. Through the analyses, it is demonstrated that our technique can effectively capture ROIs from 4D datasets.

Journal Articles

Remote visualization system based on particle based volume rendering

Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi

Nihon Shimyureshon Gakkai Rombunshi, 6(2), p.15 - 26, 2014/09

In this paper, we propose a novel remote visualization system based on particle-based volume rendering (PBVR). The system consists of a Server, which generates particles (rendering primitives), and a Client, which process volume rendering, and particles are transferred from Server to Client. The size of particle data is determined by the resolution of rendering images, and is significantly smaller than the original volume data. The smallness of the particle data is useful also for achieving a high frame rate. In the system, Server is highly parallelized on multiple GPGPUs using a hybrid MPI-CUDA programing model. The particle generation is accelerated by two orders of magnitudes compared with CPU, and structured and unstructured volume data with a hundred million cells are processed within a second. The total performance of remote visualization is compared against a commodity visualization tool, and an order of magnitude faster processing speed is achieved.

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