Masahiro Hiji

Cesium radioactivity in peripheral blood is linearly correlated to that in skeletal muscle: Analyses of cattle within the evacuation zone of the Fukushima Daiichi Nuclear Power Plant

The accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) released a large amount of radioactive substances into the environment. Furthermore, beef contaminated with radioactive cesium above the 500 Bq/kg safety standard was circulated in the food chain in 2011. Japanese consumers remain concerned about the safety of radioactively contaminated food. In our previous study, we detected a linear correlation between radioactive cesium ((137) Cs) activity in blood and muscle around 500 to 2500 Bq/kg in cattle. However, it was unclear whether the correlation was maintained at a lower radioactivity close to the current safety standard of 100 Bq/kg. In this study, we evaluated 17 cattle in the FNPP evacuation zone that had a (137) Cs blood level less than 10 Bq/kg. The results showed a linear correlation between blood (137) Cs and muscle (137) Cs (Y = 28.0X, R(2)  = 0.590) at low radioactivity concentration, indicating that cesium radioactivity in the muscle can be estimated from blood radioactivity. This technique would be useful in detecting high-risk cattle before they enter the market, and will contribute to food safety.

Genetic Algorithm to Optimize Fitness Function with Sampling Error and its Application to Financial Optimization Problem

In this paper we discuss the optimization problems with noisy fitness function. On financial optimization problems, Monte-Carlo method is commonly used to evaluate the optimization criteria such as value at risk. The evaluation model is often very complex which needs considerable computational overheads. In order to realize efficient optimization of financial problems, we propose a method to decide the number of samples used to estimate the optimization criteria. Selection efficiency proposed in this paper is a index that shows how close the population approaches to the convergence to a good solution. In general, it is difficult to calculate selection efficiency analytically. Thus we also employ bootstrap method to estimate selection efficiency. The resulting algorithm is applied to the optimization of the procurement plan optimization problem. The result shows that value at risk of the problem is optimized efficiently by the proposed method.

Software development for estimating the concentration of radioactive cesium in the skeletal muscles of cattle from blood samples

The 2011 earthquake severely damaged the Fukushima Daiichi Nuclear Power Plant (FNPP), resulting in the release of large quantities of radioactive material into the environment. The deposition of these radionuclides in rice straw as livestock feed led to the circulation of contaminated beef in the market. Based on the safety concern of the consumers, a reliable method for estimating concentrations of radioactive cesium in muscle tissue is needed. In this study, we analyzed the concentrations of radioactive cesium in the blood and skeletal muscle of 88 cattle, and detected a linear correlation between them. We then developed software that can be used to estimate radioactive cesium concentrations in muscle tissue from blood samples. Distribution of this software to the livestock production field would allow us to easily identify high-risk cattle, which would be beyond the safety regulation, before shipping out to the market. This software is planned to be released as freeware. This software would contribute to food safety, and aid the recovery of the livestock industry from the damage creacted by the 2011 Tohoku earthquake and tsunami.

Modeling manufacturing resources based on agent model

In order to improve the responsiveness to changes and uncertainties around production activity, we should have the integrated methodology which allows us to uniformly model and design the total system including production and planning resource and related information exchanged among resources. We propose the agent model and the modeling methodology. There are two types of the agent in our model. One is a service agents that offers some processing functions. The other is a mobile agent that moves among service agents. A manufacturing resource is modeled as one of the service agents since it provides manufacturing functions. On the other hand, each lot or production instruction information controlling production progress can be model as one of the mobile agents.

A Session Management Method to Improve Web Applications Usability on Mobile Network

In the traditional Web applications, the valid duration of session is set short enough to decrease risk of session hijacking and to release memory of unnecessary session objects as soon as possible. When the access time exceeds the valid duration and the session expires, the clients of the Web applications must send requests and data all over again from the beginning. The resubmission decrease easy to use Web applications. On the mobile network, we encounter such situation frequently. To solve this problem, we propose a new session management method that manages the valid duration of session and data respectively in separate objects instead of managing them in one object together. We compare the performance of proposed method with that of conventional method and show that the proposed method realizes the convenience on the mobile network

A new session management method for efficient mobile access to web applications

Valid session duration of traditional Web applications is usually set short to decrease risks such as session hijacking and to avoid waste of the computational resources. When a client exceeds the valid duration of the idle time, the session of the client expires. After the expiration, the client must send requests and data all over again from the beginning in order to resume the session. Such resubmission irritates the users of Web applications and decreases their ease of use. On the mobile networks, we encounter such situation frequently. In this paper, we propose a new session management method that resolves this problem by managing the session information and the data of Web applications separately. We investigated the performance of the proposed method applied to a Web application for business use. We will show the result that the proposed method realizes better usability while satisfying performance for the business Web applications.

An experiment of transmitting regional live pictures by wireless communication system

The Internet is a new communication media that allows users to collaborate in creating their own contents. It is expected that the demand of users to send and receive live pictures of local scenes easily at the low cost will grow rapidly. Therefore, we built the live picture servers with the Internet-connected network environment using a wireless communication system and performed an experiment of transmitting live pictures. By this experiment, we confirmed that the wireless communication system is very useful for transmitting regional information contents such as real-time multimedia data to the regional community. Further, it has become clear that the mechanism has to control the frame rate of the live picture server depending on the transmission rate between the users and the application gateway in order to achieve the smooth transmission of live pictures via an application gateway on the Internet.

A New Genetic Representation and Common Cluster Crossover for Job Shop Scheduling Problems

This paper describes a genetic algorithm approach for sequencing problems especially for job shop scheduling. In actual problems, setup time should be optimized. In order to reduce setup time, we developed a new genetic representation and an efficient crossover operator called Common Cluster Crossover (CCX). In our representation, chromosomes represent the shift of the order in sequence. To preserve sub-sequences in crossover operations, we implemented the process to identify the cluster of the sub-sequences and applied CCX that exchanges common clusters between two parents. The approach was tested on two standard benchmarks and applied to and audio parts manufacturer. CCX achieved remarkable results on the actual job shop scheduling problem.