Hideki Tanuma

SOARS: Spot Oriented Agent Role Simulator — Design and Implementation

Summary In this paper we present the design of an agent-based simulation language called SOARS (Spot Oriented Agent Role Simulator). SOARS is designed to describe agent activities according to roles within social and organizational structures. Role taking processes can be described in our language. SOARS is also designed according to the theory of agent-based dynamic systems. Decomposition of multi-agent interaction is one of the most important characteristics of our framework. The notion of spot and stage gives spacial and temporal decomposition of interaction among agents. We apply our multi-agent framework to policy analysis of emerging virus protection in the case of SARS. In the latter part of the paper, we explain the implementation of the SOARS simulation platform. The simulation engine and related built-in functional objects are implemented in Java language. An application user can describe the agent-based simulation model only by writing script in SOARS script language without knowledge of Java classes. If needed, the user can customize the function of SOARS by implementing additional Java classes. The easiest way to customize is to develop special functional objects, and the SOARS platform will be the interface between such customized objects.

Anti Pandemic Simulation by SOARS

Next pandemic caused by human to human outbreak of mutated H5N1 bird flu is almost inevitable. To prevent the pandemic we must take steps not only from medical point of view but also from social program point of view. In this paper we propose four categories of social protection programs. We modeled the infection process under the social activities of agents by using SOARS (Spot Oriented Agent Role Simulator). We evaluated the effectiveness of the social programs to protect the pandemic by agent based simulation. As a result we found that there exists a critical bifurcation point between eradication and spreading by controlling the combination of social protection program

A new operator for describing topographical image structure

To develop a computer vision system, it is necessary to define a proper image structure representation to be used for interpreting images efficiently. In this paper, we propose a new operator called shape operator for describing topographical image structure. We consider an image function as a surface, then describe a shape of each pixel comparing with its neighbourhood in terms of topographical shapes such as hill, dale, ridge, valley, etc. The shape operator is established by utilizing the eigenvalue of Hessian of an image function. It is expressed in an explicit form in terms of the second order partial derivatives of an image function. We show how to derive this operator, its interesting properties, and an application for texture classification. Experimental results show its good performance for discriminating texture imaged. Especially, it can give the same interpretation of an image reflected in different lighting conditions since it has the invariance properties under linear and monotonic gray tone transformations.

Hardware Implementation of Parallel SOARS using FPGA based Multiprocessor Architecture

We are developing an agent-based simulation language, SOARS (Spot Oriented Agent Role Simulator), aiming standard descriptive language to express complicated social system. SOARS is a simulation language with original model concept to describe agent’s interaction. Currently, SOARS processor is implemented by JAVA, and agent rule is successively processed. However, model concept of SOARS is originally headed for parallel execution of agent rule, and it is preferable to prepare for high-speed implementation performing right parallel operation by common simulation description. Therefore, we decided to investigate the problem in language specification at the time of parallelizing, construct and monitor the system that is small-scaled but enables actual parallel operation.

Design of a hybrid-learning environment based on SOARS

Recent development in bottom-up modeling, through educational games, enables students to understand overview of complicated socioeconomic systems. We apply SOARS (Spot Oriented Agent Role Simulator) for designing hybrid-learning environment. In the hybrid-learning environment, both of students and computer agents interact each other and learn socioeconomic systems simultaneously.

Evaluation of transaction risks of mean variance model under identical variance of the rate of return – simulation in artificial market

Mean Variance (MV) model has spread through institutional investors as one of the most typical diversified investment model. MV model defines the investment risks with the variance of the rate of return. Therefore, if any variances of two portfolios are equal, MV model will judge that the investment risks are identical. However, even if variances are equal, two different risk cases will occur. One is just depended on market volume. The other is fully depended on speculators who raise stock prices when institutional investors are purchasing stocks. Consequently, the latter makes institutional investors pay excessive transaction costs. Development of ABM (Agent Based Modeling) in recent years makes it possible to analyze this kind of problem by simulation. In this paper, we formulate a financial market model where institutional investors and speculators trade twenty stocks simultaneously. Results of simulation show that even if variances are equal, investment risks are not identical.

The Effects of Vaccination Strategies Against Smallpox Bioterrorism with Agent-Based Simulation

This chapter aims to estimate the extent of damage in the case of an outbreak of smallpox terrorism, based on agent-based modeling. The purpose of this study is also to discuss effects of social protection policies, such as vaccination and quarantine. The authors developed a smallpox epidemic terrorism simulation using SOARS. The simulation assumes exposure of smallpox virus in a city with a population of 10,000. The results of the simulation show (1) The implementation of early school closure and vaccination significantly reduces the number of infected persons despite the limited amount of vaccine supply; (2) vaccination is a method to acquire immunity for younger (non-immune) generations; thus, the difference in vaccination strategy influences the trend of outbreak among patients; (3) if the school closure and vaccination are delayed more than 20 days, the effect of suppressing the spread of infection falls.

A Study on Countermeasures against Computer Virus Propagation Using an Agent-based Approach

An increase of computer viruses in recent years caused big damage on the Internet or intranet in public offices and enterprises. The damage influences at the life of the people and becomes serious problems. This paper aims to study anti-virus policies to limit damage of network system from aspects of network operation. The authors propose a diffusion model of computer viruses using agent-based approach and clarify diffusion phenomena by simulations. They also consider countermeasures against computer virus propagation by means of aforesaid method.