Many manufacturing firms cause environmental problems such as greenhouse gas emissions in the process of carrying out their production activities. In evaluating the performance of prefectures, it is of great importance to consider curbing greenhouse gas emissions. The purpose of this paper is three-fold. First, we introduce an environmental dynamic-network slacks-based model that enables us to evaluate the performances of 47 Japanese prefectures. In this model, the prefectures are assumed to produce the by-product of CO₂ as well as the main good output of gross domestic product by utilizing four parallel sectors (the human capital, physical capital, energy consumption and intermediate input sectors), each of which also employs the carry-over product from the previous period and a new carry-over product to the next period. Second, we explore the factors affecting the overall efficiency using a bootstrap regression procedure. Finally, we offer some policy suggestions.

This paper conducts a laboratory experiments using human subjects of network formation, and formation of periphery-sponsored star networks are observed. In the network formation process, multiple replacements of the central players of the peripheral-sponsored star networks are observed as like some laboratory experiments conducted in related works. The related work of the network formation interprets such irrational decision as a result of implicit agreement of the subjects, and they construct a behavioral model based on concepts of correlated equilibrium. However, the behavioral model ignores a part of network formation process, therefore it can explain only several aspects of the subjects' behavior. This paper modifies the behavioral model based on the correlated equilibrium focused on adaptive decision process.

In this paper, we propose a multiple facility location problem to minimize inequality in distances to facilities. The inequality is evaluated by Quantiles Share Ratio (QsSR) that is a generalized version of Quintile Share Ratio (QSR). QSR is an inequality measure of income distribution defined as the ratio of total income received by the 20% of the population with the highest income (top quintile) to that received by the 20% of the population with the lowest income (lowest quintile). Drezner et al. (2014) have proposed single facility location problems using QSR where the inequality in distances to the facility is considered and the value of QSR is analytically derived at specific points such as the center of a circle and a rectangle, and vertices of a rectangle. Also, the paper mainly focuses on single facility location problems. In this paper, we develop a mathematical programming model seeking locations that minimize QsSR and propose a binary search method to solve the model. Furthermore, we extend the model by incorporating a total distance constraint. The models are applied to the case study of Arakawa ward in Tokyo using geographical and population data. Results show that our model provides low inequality locations with small increase in the total distance compared with the locations that minimize the total distance.

The first-year students of the Faculty of Science and Technology of Keio University belong to one of the five groups and are allocated to eleven departments just before proceeding to the second grade. Each student must be allocated to one of the three or four departments pre-assigned to her/his group. By constraints on quotas between the groups and the departments, the standard students/departments stable allocation problem is not applicable to this allocation problem. Since eight departments accept students from two groups, a decision-maker, who allocates the first-year students to the departments, repeatedly decided the quotas between the groups and the pre-assigned departments, and solved the standard students/departments stable allocation problem, by trial and error.

In this paper, we propose a variant of the students/departments stable allocation problem in which the students are partitioned into several non-empty sets, and develop two algorithms for the variant or its relaxation problem. We also report results of two algorithms applied to real students/departments allocation problems of the Faculty of Science and Technology of Keio University in academic years 2015 and 2016. Our algorithm applying discrete convex analysis gave nice results for the real allocation problems.

The focus of this study is to propose the optimization technique to solve the multi-member constituency system, which selects multiple members from a single constituency. In the optimization model, the objective function is to minimize the maximum difference of one vote for the electoral district. In addition, using this technique, we present the optimal division for each parliamentary election of 47 prefectures. As a result, the limit value of the maximum difference of one vote is obtained for each prefecture. Furthermore, based on this result, we can evaluate and analyze the current division of local elections (prefectural assembly elections) which has a large difference compared with the national election (the single-member constituency system in the House of Representatives).

In the well-known repeated prisoner's dilemma game, how to achieve cooperative behaviors among both players has been the main concern, like the fork theorem.

In contrast, in this paper we formulate, by using the theory of standard discrete time stochastic processes, a non-symmetric repeated prisoner's dilemma game in which player 1 can stop the game immediately when player 2 has chosen “D”strategy. In consequence, we can rigorously prove that player 1 and player 2's strategy set (all D, all C ) is the best Nash equilibrium for player 1 among any other strategy sets.