Respiratory motion can induce the limit in the accuracy of area irradiated during lung cancer radiation therapy. Many methods have been introduced to minimize the impact of healthy tissue irradiation due to the lung tumor mot ion. The purpose of this research is to develop an algorithm for the improvement of image guided radiation therapy by the prediction of motion images. We predict the motion images by using principal component analysis (PCA) a nd multi-channel singular spectral analysis (MSSA) method. ...
英字タイトル:
Development of motion image prediction method using principal componentanalysis

Abstract: Preparation for DEC (design extension condition) is one of the lesson learned from Fukushima nuclear accident. From the structural point of view, it is needed to know the failure modes of the pipe structure to make adequate preparation against excessive seismic loading. But the failure modes under seismic loading are still not clear. Low cycle fatigue is one of the major failure modes observed at seismic experiments. Ratcheting is also observed at some other experiments. And collapse is assum...
英字タイトル:
Failure modes investigation of pipe structure under excessive seismic loading

Abstract: A hybrid, noncontact laser-EMAT ultrasonic system, using a pulsed laser for ultrasound generation and an EMAT (electromagnetic acousti c transducer) for ultrasound detection, is developed and studied on NDT of crack in materials. Instead of using longitudinal diffraction wave i n the conventional TOFD method, the LTS mode-converted wave scattered from the crack tip is recommended to be applied in the laser-EMAT TOFD mea surement. A modified time-of-flight (TOFD) method based on laser-EMAT ultraso...
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Laser-EMAT ultrasonic testing of cracks with TOFD method

Recently the importance of nuclear security is increased after Fukushima Daiichi Power Plant accident. Especially as the threat to nuclear power plants, sabotage by insider is significant. In this research, the technology to detect malicious behaviors by insiders was developed by video camera movie. Time series data analysis is a useful method in abnormal behavior detection. However, abnormal behavior detection isn’t enough for nuclear security, future malicious behavior prediction should be considered...
英字タイトル:
Sign Detection of Future Malicious Behavior for Nuclear Security

In this study, the prediction method for time-series data was developed and its validity was verified by the comparison of the measured time-series and the predicted one. The measured time-series data was obtained as the laser displacemen t meter's output observing the human's chest movement during breathing. The Singular Spectral Analysis method (SSA) was applied as the prediction analysis method. The comparison showed good agreement of the measured and the predicted ones....
英字タイトル:
Diagnosis of Dynamic Equipments by SSA Method

Image guided radiation therapy (IGRT) has played a major role in the precision of radiation therapy especially while tracking moving tumors. The IGRT units are capable of 2D planar imaging, fluoroscopy etc. As lung tumor tends to move and deform during respiration, it also undergoes a sudden phase change in motion due to sudden cough or sneezing during the treatment which leads to the treatment beam missing the target. In this study we propose an algorithm for tracking moving tumors during radiation t...
英字タイトル:
Sudden change detection in moving tumors for dynamic tracking in lung cancer radiation therapy

We have developed a new index called Resilience index, which evaluate the reliability of system safety of nuclear power plant under severe accident by considering the capability to recover from the situation the system safety function was lost. In this paper, a detailed evaluation procedure for the Resilience index was described. System safety of a PWR plant under severe accident was then assessed according to the Resilience index concept to discuss applicability of the index. We found that the Resilie...
英字タイトル:
Fundamental Study on Applicability of Resilience Index for System Safety Assessment

We have established a procedure for comprehensive safety assessment of aging plant using a combination of two indices; risk index and resilience index. And, we have identified important equipment using a simple resilience index and have extracted failure mode using a risk index with detailed plant model. Those were applied to three loop PWR plant as trials. We are reporting its summary and considering the effectiveness of the resilience index. ...
英字タイトル:
Development of Comprehensive Safety Assessment Method for Aging Nuclear Power Plant Using Risk Index and Resilience Index

Rapid response processes are essential for enabling resilience, which provides a potential target for assessment. The response cycle is considered in three phases: (1) information transmission from system to Decision-Maker, (2) information processing, and (3) feedback action on the system. This research focuses on the first of the three phases, information transmission, and proposes a novel resilience assessment using an Information-Theoretic approach. From this point of view, resilience is considered t...
英字タイトル:
An Information-Theoretic Approach to Resilience Assessment

We have proposed new indices for evaluating resilience, that is, the response margin and response reliability of a nuclear power plant during an accident and detailed procedure for assessing those indices. In this study, the resilience of a simple fast reactor plant model is evaluated according to the indices. The applicability of the resilience evaluation method to fast reactor plants is then discussed from the viewpoints of reflecting the characteristics of each reactor type....
英字タイトル:
Fundamental Study on Applicability of Resilience Evaluation Method to Fast Reactor Plants