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Journal Articles

Development of an external radiation dose estimation model for children returning to their homes in areas affected by the Fukushima Nuclear Accident

Mori, Airi; Takahara, Shogo; Yoshida, Hiroko*; Sanada, Yukihisa; Munakata, Masahiro

Health Physics, 117(6), p.606 - 617, 2019/12

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

Journal Articles

Visualization of overlay network using autonomous system relationships

Miyamura, Hiroko; Hu, H.-Y.*; Yoshida, Masahiro*; Ozahata, Satoshi*; Nakao, Akihiro*; Takahashi, Shigeo*

Shingaku Giho, 112(463), p.577 - 582, 2013/03

This report presents a method for visualizing scale-free networks including Overlay networks as an typical example. Visualizing large-scale and complicated networks such as social networks has recently been very popular while conventional network visualization techniques cannot allow us to understand the topological structure of the scale-free networks. This is because the vertex degrees vary at an exponential rate in the scale-free network and thus special attention should be given when visualizing the network connectivity and analyzing the network traffic there. In this report, we employ the hierarchical representation of the scale-free network by referring to their vertex degrees and autonomous system relationships, so that we can clearly visualize the topological structure of the network in 3D space and retrieve the traffic paths over the network.

Oral presentation

A Multilevel graph layout for analysing of large-scale network datasets

Miyamura, Hiroko; Yoshida, Masahiro*; Ozahata, Satoshi*; Takahashi, Shigeo*; Nakao, Akihiro*; Kawashima, Konosuke*

no journal, , 

We propose a multilevel graph layout technique for visualizing large scale network datasets. Large-scale datasets are said to be difficult to analyze and visualize. However, with our technique, the datasets can be displayed in multistep. For instance the outline of network dataset is shown first, and when focused on a certain region, the detailed information is shown as well. By using this technique, users can observe a large scale dataset from the outline to the detail seamlessly, and therefore this is valuable for the structural analysis of network datasets.

Oral presentation

Committee on dose assessments of Japanese population

Takahashi, Fumiaki; Ishimori, Yuu; Inagaki, Masayo*; Omori, Yasutaka*; Sanada, Tetsuya*; Sugino, Masato*; Furukawa, Masahide*; Hosoda, Masahiro*; Manabe, Kentaro; Yajima, Kazuaki*; et al.

no journal, , 

The Japan Health Physics Society (JHPS) established a committee on dose assessments of Japanese population in August, 2015. The committee consists of 12 members (researchers and technicians) who are engaged in natural radiation measurements, radiation monitoring, radiation dose assessment and so on. Discussion have been made on dose assessments for daily life exposure in Japan. At the first meeting, stragedy of the committee was discussed and terrestrial radiation, cosmic radiation. Radon and radioactivity in food were defined as the radiological source to be investigated. It was also decided that the committee also would investigate influential factors (e.g., dose assessment model, daily life pattern) on radiation dose assessments. In addition, the committee has a plan to make discussions how JHPS should undertake this issue in future. At the 49th Annual meeting of JHPS, the committee members report their activities and make discussions on radiation dose assessment of Japanese population with the participants to the meeting.

Oral presentation

Study on influence of radioactive contamination derived from nuclear power plant accident on building space, 2; Study on measurement method of direction radiation dose rate intended for field survey

Yamamori, Ryo*; Kobayashi, Hikaru*; Honta, Shohei*; Yoshino, Hiroshi*; Nozaki, Atsuo*; Ichijo, Yusuke*; Yoshida, Hiroko*; Furuta, Takuya

no journal, , 

Understanding radiation field is important to predict radiation dose rate in newly constructing buildings in an area widely contaminated by radioactive nuclei. Radiation dose rate at the site is not sufficient, and directional spectra of the radiations are important to consider the shielding effect of the building. Radiation directional spectra can be measured by scintillator partially shielded by lead collimators but the angle of view highly depends on the combination of the scintillator and the collimators. We adopts a method to measure the directional spectra by adopting 3 inch scintillator with placing a plate of lead collimator in front of the scintillator and subtract the values from the spectra measured without lead collimator. We simulates the optimal size of the lead collimator and found that the 15 cm diameter plate placing at 3 cm from the scintillator is the best for our purpose, 90 degree angle of view.

Oral presentation

Development of $$gamma$$-ray directional radiation dose detector with good efficiency for field survey

Yamamori, Ryo*; Kobayashi, Hikaru*; Honta, Shohei*; Yoshino, Hiroshi*; Nozaki, Atsuo*; Ichijo, Yusuke*; Hijikata, Yoshio*; Yoshida, Hiroko*; Furuta, Takuya

no journal, , 

Understanding radiation field is important to predict radiation dose rate in newly constructing buildings in an area widely contaminated by radioactive nuclei. Directional spectra of the radiations are important to consider the shielding effect of the building. We adopts a method to measure the directional spectra by adopting a plate of lead collimator in front of the scintillator and subtract the values from the spectra measured without lead collimator. We investigated a possible weight saving detection system having sufficient detection efficiency. The investigation was carried out for the condition of the collimator radius ($$phi$$ = 10, 15, 20 cm) and the distance between collimator and detector ($$ell$$ = 1, 3, 5 cm). We found that three combinations satisfied the 90$$^{circ}$$ field view and the detection efficiency became better with larger collimator radius. On the other hand, larger collimator radius indicate heavier detection system. Therefore, we developed an optimum detection system for field survey with the 15 cm diameter plate (10kg), the scintillator (3.4kg), and the folder (1.0kg).

Oral presentation

Oral presentation

Investigation on distribution of radiation in Joban Expressway, 2; Results of walk-survey and car-survey along the Joban Expressway

Takemiya, Hiroshi; Saito, Kimiaki; Yoshida, Hiroko*

no journal, , 

Walk survey and Car survey has been carried out to measure the air dose rates on the berm as well as on the driving lane between Hirono and Minami-Soma interchanges of the Joban Expressway. Spatial distribution and temporal change of the air dose rate are reported.

Oral presentation

Evaluation of internal exposure to residents due to indoor radiocaesium contamination in residential houses near the FDNPP

Yoshida, Hiroko*; Shinohara, Naohide*; Manabe, Kentaro; Higaki, Shogo*

no journal, , 

no abstracts in English

Oral presentation

International Affairs Committee Session; Introduction of current international trends

Yoshida, Hiroko*; Yasuda, Hiroshi*; Takahashi, Fumiaki; Dobashi, Ryuta*; Hattori, Takatoshi*

no journal, , 

The Japan Health Physics Society (JHPS) is a member of the International Radiation Protection Association (IRPA). Many researchers and technicians of radiation protection join JHPS in Japan. The international affairs committee in JHPS holds a session to introduce recent trends and information about radiation protection over the world in annual meeting. In the 51st Meeting, Dr. Yoshida (Tohoku Univ.) will talk about the recent activities of task groups in IRPA. Dr. Yasuda will explain radiation protection in aviation given by ICRP Publication 132. Dr. Dobashi will introduce recent discussions on the safety standards by IAEA. Takahashi (JAEA) will explain Occupational Intakes of Radionuclides (OIR) given by ICRP Publications 130, 134 and 137.

Oral presentation

Indoor radiocaesium contamination in residential houses near the FDNPP and evaluation of internal exposure to residents

Yoshida, Hiroko*; Shinohara, Naohide*; Manabe, Kentaro

no journal, , 

no abstracts in English

Oral presentation

Investigation on distribution of radioactive substances in Fukushima, 14; Distribution of air dose rates along the Joban Expressway

Takemiya, Hiroshi; Saito, Kimiaki; Yoshida, Hiroko*

no journal, , 

Airdose rates along between Hirono and Minami-Soma Interchanges of the Joban Expressway has been measured since the resume of the expressway. The paper describes the spatial and temporal distribution of air dose rates of the expressway.

Oral presentation

Analysis of materials about radiation provided to residents after the Fukushima accident and considerations of a method to evaluate; The Efforts of SG1

Kono, Takahiko; Hattori, Takatoshi*; Yokoyama, Sumi*; Nakano, Hironori*; Sato, Noriko*; Kudo, Hiromi*; Nomura, Naoki*; Sakoda, Akihiro; Naito, Wataru*; Kuroda, Yujiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Difference in activities of some academic societies toward the society between before and after the Fukushima Accident

Sakoda, Akihiro; Nomura, Naoki*; Naito, Wataru*; Kono, Takahiko; Kuroda, Yujiro*; Yoshida, Hiroko*

no journal, , 

no abstracts in English

Oral presentation

Characteristics of air dose rate distribution around houses in Iitate Village, Fukushima Prefecture

Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki

no journal, , 

no abstracts in English

Oral presentation

Characteristics of air dose rate distribution inside and outside wooden houses after the Fukushima Daiichi Nuclear Power Plant accident

Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki

no journal, , 

no abstracts in English

Oral presentation

Oral presentation

Investigation on distribution of radioactive substances in Fukushima, 7; Study on reduction factors calculated using continuously monitored air dose rates around houses

Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki

no journal, , 

no abstracts in English

Oral presentation

Investigation on distribution of radioactive substances in Fukushima, 6; Temporal changes in reduction factors by wooden residential houses within former/current evacuation areas

Yoshida, Hiroko*; Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya

no journal, , 

no abstracts in English

Oral presentation

Role of radiation protection (RP) professionals in developing and fostering RP culture in general public

Yoshida, Hiroko*; Kuroda, Yujiro*; Kono, Takahiko; Naito, Wataru*; Sakoda, Akihiro; Nomura, Naoki*

no journal, , 

no abstracts in English

23 (Records 1-20 displayed on this page)