消費者行動の研究では, 知覚価格を説明するために参照価格をはじめ様々な価格概念が提唱されており, その分析に多項ロジット・モデルが幅広く適用されている.一方, ゲーム理論を用いた競争戦略の研究においても同様に知覚価格が考慮され, 多項ロジット・モデルが適用されている.しかし, これらのモデルはいずれも消費者効用を製品価格に関して一次の関数としているため, 参照価格, 留保価格以外の概念で知覚価格を取り扱うことは困難である.本研究では, 効用関数を製品価格に対して非線形な関数とすることにより知覚価格を捉え, そのときの価格決定を支援するモデルを提案する.はじめに均衡解が複数個存在することを想定して, 均衡解の極値条件を満たす局所的な均衡解の比較静学分析を行なう.次に数を2に限定して, 均衡解が一意に定まる条件について考察する.最後に小規模なサンプルを用いた数値実験を行なう.なお, 本研究では製品価格に関する効用関数の曲率により知覚価格の特徴を解釈する.

抄録全体を表示

宅配便業界最大手のヤマト運輸は，ドライバーの長時間労働が問題となっている．インターネット通販大手のアマゾンが市場規模を拡大させ，ヤマト運輸の宅配便取扱数が増加していることが影響している．特に，夜間配達が増加している．アマゾンが有料会員に対し，最も早い場合は注文が確定した当日に配送するサービスを展開しているためである．2017年4月にヤマト運輸は当日配送から撤退した．本論文では上記の状況を，コンフリクト解決のためのグラフモデル(GMCR)を用いてモデル化する．

，GMR，SMR，SEQという4つの安定性概念に基づく均衡を計算機で求める．求めた均衡と現実の結果を比較し，考察を行う．

抄録全体を表示

In this paper, we deal with a cooperative production planning model in which multiple firms mutually pool a part of resources procured by themselves. Although the firms are cooperative in the sense that pooling of the resources is allowed, we consider an equilibrium model in which the firms maximize their own profits and a

equilibrium point with respect to their profits is calculated. Finally, we show allocation schemes based on a cooperative game arising from the cooperative linear production planning with pooling of the resources because the total profit of all the firms in the cooperative production planning model is larger than that in the independent production planning model without pooling. Calculating the equilibrium points of a numerical example with various pooling rates and the corresponding profit allocations, we demonstrate the validity of the proposed cooperative production planning model.

抄録全体を表示

The purpose of this paper is to investigate the dynamic properties of environmental R&D and environmental policies by analyzing the infinite horizon differential game between two governments. In this paper, we formulate the differential games that need to be solved by the two governments and derive and characterize the unique open-loop and Markov-perfect equilibrium solutions. By comparing the two equilibrium solutions, we explore the free-riding behavior of governments with regard to pollution control. We derive and compare the steady-state levels of emission tax, pollution stock and social welfare. In addition, we derive the convergence speed of pollution control under the respective equilibrium solutions. In conclusion, compared to the Markov-perfect equilibrium solution, we obtain a higher emission tax, a lower pollution stock, a higher social welfare and a slower pace of pollution control under the open-loop equilibrium solution.

JEL classification: F18, L13, Q58

抄録全体を表示

固体材料の熱拡散率を1600Kから2500K以上まで測定可能なレーザフラッシュ法熱拡散率測定装置を開発した。本装置の性能を評価するため、米国国立標準技術研究所（NIST）において熱拡散率が測定されたPOCO AXM-5Q1高密度等方性黒鉛試料（NIST RM8424）の熱拡散率を測定した。同一試料に対する両装置の熱拡散率測定値の平均値の偏差は1600Kから2500Kの温度範囲で１％以内であった。また、グラッシーカーボンおよび２次元炭素／炭素複合材料の試料について、計量研究所のレーザフラッシュ標準熱拡散率測定装置により1800K以下で、本装置により1600K以上で熱拡散率を測定した結果、室温から2500Kの広い温度範囲で装置に依らず連続的に変化する熱拡散率が得られた。

抄録全体を表示

本発表では、昨今のインタ-ネット市場に見られるような価格・品質競争に注目し、そのメカニズムについて、ゲーム理論を用いミクロ経済学の視点により分析する。その上で、がとり得る重要な戦略として製品差別化と垂直統合の２つを取り上げ、その効果についてと消費者の両面から考察する。結論として、まず品質重視の市場においては、よく知られた価格競争の結果とは異なり、差別化はのみならず消費者にとっても望ましい効果をもたらすことを示す。また垂直統合については、ヤフーが採用しているような競合相手の製品とのバンドリングを拒否した独占的な統合が、統合及びその消費者の双方にとって効果的となることを示す。

抄録全体を表示

本研究の目的は, 電力スポット価格変動を表現するモデルを構築することである. そのために, 電力取引市場をある非協力ゲームを用いて表現した. 具体的には, 電力取引市場は寡占市場であり, 貯蔵不可能性および同時同量の原則を前提とし, 電力需要量の不確実性を想定する. さらに, 各発電の供給量の上限があることを仮定する. その上で, 電力需要量の確率分布を考慮しながら自社のストラテジー(供給関数)を戦略的に2社の発電が市場へ提示するという非協力ゲームを考え, その均衡を求めた. そして, その均衡における電力スポット価格の確率分布などを求めた. さらに, このモデルを基にPJM市場のスポット価格を分析する.

抄録全体を表示

Christensen (1997) describes market share turnaround processes, based on intensive case studies of Hard Disk Drive, or HDD industry. Even though established large firms are vulnerable to disruptive innovations, previous models have not explained the underlying mechanism definitively. To address this issue, we develop and use a modified Adner and Zemsky (2005) model. In this non-cooperative game model, two firms are assumed to supply same type of product. One firm, which is assumed to be an initial significant occupant of the market, offers products manufactured with mainly established technologies, and these are superior on the primary dimension. The other firm tries to make horizontal differentiation with new technologies. The demand depends on a net effect which represents switching cost, network externality of existing products, the value created by the new technologies and so on. This enables us to consider various relations between established and new products. So we show an example in which the new product ends up a niche (secondary or isolated) market because of the cost and other advantages gained by the established technology-firm. In contrast, there is a case where the firm adopting the new technology dominates the markets and enjoys the monopoly price. Here, the new technology-product is considered to win high evaluation by consumers. This case also implies that the cost advantage is not the necessary condition for the occurrence of disruptive innovations.

抄録全体を表示

The purpose of this paper is to investigate the dynamic properties of environmental R & D and environmental policy by analyzing infinite horizon stochastic differential games between two governments. In this paper, we formulate stochastic differential games that need to be solved by the two governments, and derive and characterize the cooperative and Markov-perfect equilibrium solutions. By comparing the two equilibrium solutions, the free-riding behavior of governments can be explored with regard to pollution control. The steady-state levels of emission tax, pollution stock and value function were also derived and compared. In conclusion, we obtained a higher emission tax, a lower pollution stock, a higher value function under the cooperative solution when compared to the Markov-perfect equilibrium solution.

JEL Classification: F18, L13, Q58

抄録全体を表示

The main purpose of this paper is to investigate how dynamic R & D and R & D policy affect an international oligopolistic competition.
Suppose that there is an international rivalry between two firms (i.e., home and foreign firms), both of which export their homogeneous outputs to the third country. Suppose also that initially two firms have equal technology. In order to maximize the discounted sum of profits, two firms should decide how much to invest in R & D and how much to produce outputs.
We start from a simple export rivalry model and make it a dynamic model by introducing cost-reducing R & D made by two firms. Moreover, we allow for the possibility of R & D spillovers between two firms.
In the first part of this paper we formulate the differential games to be solved by two firms, derive and characterize the unique open-loop equilibrium. In the second part of this paper we examine the open-loop equilibrium R & D policies of the two governments.
The following results were obtained:
(1) The stationary state marginal cost of two firms depends on the parameters, that is, demand, spillover, discount rate and R & D cost parameter.
(2) The speed of convergence for the stationary state marginal cost of two firms depends on the parameters, that is, demand, spillover, discount rate and R & D cost parameter.
(3) The optimal trajectories of R & D capitals and investment strategies of two firms depend on the parameters, that is, spillover, discount rate and R & D cost parameter.
(4) The open-loop equilibrium R & D subsidies of the two governments depend on the parameters, that is, spillover, discount rate and R & D cost parameter.
These results lead to the conclusion that the stationary state level of marginal cost depend on the degree of spillover and the optimal R & D subsidies depend on the discount rate and the R & D cost.

抄録全体を表示

The main purpose of this paper is to make a game-theoretical formulation of model that can represent interactions among local governments (each of which will plan some project independently each other), firms (each of which will determine where and what to produce and his production-capacity, given projects of local governments) and consumers of firms' products. This game-theoretical formulation can help us to represent explicitly a situation where an information of a decision maker on others' decisions is significant for his decision and where his outcome is a result of not only his own decision but also others' decisions.
If there are interactions among projects of local governments, it may be difficult for local governments to evaluate outcomes of their decisions, for their decisions may not result in a unique outocome. Adopting equilibrium as solution of non-cooperative game, this difficulty corresponds to multiple equilibria, but it is likely that a non-cooperative game has multiple equilibria.
Using hypothetical and simple examples, we analyze a 2 regions-1 potential entrant case, a 2 regions-competitive entrants case, and a 2 regions-2 potential entrants case and show that an option (any local government can withdraw his published project if there is no entrant in his region) can reduce his difficulty mentioned above.
Game theory requires all players know completely the game in which they take part, but local governments not only take part in a given game, but also each of them can design some part of the game in which he can not avoid to take part in. If we can assume all local governments know all alternatives, then we can formulate their game in full. But the representation of the game in extensive form is too complex for us to deal with. So piece-meal modifications of their game can be justified if each of their modifications is acknowledged as reasonable by every participant. In this context, the above result is meaningful, though underlying assumptions are very restrictive.

抄録全体を表示

社会科学系，特に経営科学などで対象とする

の競争などといった状況は相互依存性が強く，初期状態にも依存するため，現実社会での再現性に乏しく，数理モデルなどの検証は比較的困難であるといえる．そのため，ゲーミングシミュレーションの結果を仮想現実としてとらえ，その結果と数理モデル間での検証を行うことで、間接的に検証を行うことが考えられる．本稿では，社会科学系における数理モデルの構築、もしくは結果の検証にYBGを用いた試みとして，YBGを用いて２つのゲームを作成し，それらを進化ゲーム理論の枠組みで分析する．

抄録全体を表示

現在肥満や糖尿病が急増していることから，非アルコール性脂肪性肝疾患（nonalcoholic fatty liver disease：NAFLD）の有病率は上昇することが予想され，世界中で慢性肝疾患の主因となっている．肝線維化は，NAFLD患者の長期転帰の悪化と関連がある．さらに，死亡率の上昇と肝疾患の合併症は，主に非アルコール性脂肪性肝炎（nonalcoholic steatohepatitis：

）患者に見られるが，非アルコール性脂肪肝（nonalcoholic fatty liver：NAFL）は，良性で比較的進みにくいと考えられている．そのため，とNAFLの鑑別が，臨床的に重要である．肝生検は，肝線維化の病期分類およびとNAFLとの鑑別のゴールドスタンダードとして用いられている．しかしながら，肝生検は侵襲的で，高額な検査法である．したがって，肝線維化の病期分類と診断のために，生検に代わる非侵襲的方法が緊急に必要とされている．本論説では，肝線維化，肝脂肪化および炎症や肝細胞風船様腫大を含む肝障害など，の病理学的所見を反映可能な，磁気共鳴エラストグラフィを含む磁気共鳴画像法（magnetic resonance imaging：MRI），プロトン密度脂肪分画測定法，マルチパラメトリックMRI（multiparametric MRI：mpMRI）に関する近年の研究を考察する．

抄録全体を表示

In this article, the nature of structural problems in the current support activities for sports as corporate philanthropy is analyzed first, using the theories of L.Kohlberg on the moral development. In the just community based on the morality at the high level of the moral stage, the members can establish mutual trust, and besides, they can promote the further moral development in the community. In the environment based on the morality at the high level such as in the just community, there is "fairness." The conditions of forming "fairness" are based on the "social ethical preference," provided by effective means to judge ethical or unethical corporate behavior correctly and to influence over the corporate behavior. L. proposes that moral leadership in the business environment can create the values and trust between businesses and the society. The corporations can integrate ethical behavior with economic success, making mutually beneficial for the both sides of people who support and who are supported. Thus, the relationship based on the "Fair Contractual Corporate Ethics" in communities can create an ideal situation.

抄録全体を表示

本論では, 新規参入のための競争戦略分析モデルを提案する.Carpenterら(1990)は消費者選好の非対称性(Preference Asymmetry)が存在する市場への参入戦略を分析するモデルを提案している.しかし, このモデルでは, マーケットシェアが抽象的関数であるため, 分析の対象が独占市場に限定される, 加えて, 製品コストと製品ポジションの依存関係も考慮されていないため, 価格, 製品ポジションニングといった意思決定に対して定性的な結論しか得られない.そこで, 本論では具体的な消費者行動モデルとして多項ロジット・モデルを適用することにより, 分析の対象を寡占市場に拡張する.さらに, 前述の依存関係を考慮することにより, 消費者選好の非対称が存在する寡占市場へ参入する際の最適な製品価格, 製品ポジションを定量的に求めるモデルを提案する.

抄録全体を表示