Globalization has been widely infiltrating into our life from any aspects, and even the building con-struction industry couldn't keep itself away from this trend. Since 1970s, numerous construction companies had been eager to expand global wide by chasing after the immense infrastructure in-vestment in those Middle Eastern oil-producing countries. Meanwhile, Japanese construction indus-try was also dedicating to the international market share by starting with building overseas factories or branch office for Japanese enterprises to participate this game. Unfortunately, the overseas revenue never constantly contributes to the growth of company. Moreover, litigation, procrastination, budget overrun became daily routine in this field.

Although a large quantity of resource has been deployed into this field, little is known about what kind of organization consciousness fundamentally shapes the difference of construction methodology among countries which would jeopardize the success of transnational project. Numerous attempts have been made to create a systematic understanding how those different countries would work together seamlessly. As to that, adversarial behavior was one of the most important subjects to this attempt. However, the behavior mechanism is still a missing piece of this puzzle.

Most of researches and practice have been noticing that the culture difference is one of the major factors leading to the failure of transnational building construction. This research is trying to establish a mechanism model to demonstrate how the adversarial tendency of differential culture difference would affect the relationship between modularity and interface, and how it leads to the outcome of transnational building project consequently. Furthermore, this research would attempt to find an interdependence model to locate the possible risk area, and improve the advanced planning process accordingly.

A typical building construction is basically dealing with two major elements, the material behavior and the human behavior. Taking both material and human behavior into building construction pro-jects as analysis subjects is difficult to operate within one model due to the natural property of these two element are very different. Fortunately, in the book of "Design Rules, Vol. 1: The Power of Modu-larity" by Prof. Carliss Y. Baldwin and Prof. Kim B. Clark, the concept of task has been introduced to public to solve this issue. Both material behavior and human behavior can be investigated at the same level as a task.

Even creating an artifact, we would need to execute many serial- parallel tasks in order to complete and deliver the final outcome. As to the function of modern artifact, it is always getting more and more complicated, and the divisions of works become more and more professional for some reasons, such as cost efficiency, or oligopoly market. As a result of that, tasks would always be grouped to achieve the best efficiency by several different players, and the interface among task group would be created accordingly. By following the same principle, an artifact could be grouped in a different way determined by different kind of players. Especially, when an artifact is made by multiple players across countries, which usually result in different kind of grouping principle, and creates different module layout accordingly.

This research attempts to put the transnational building construction industry into a differential sociological impact model by using the modularity observation methodology with task dependence model, and tries to figure out a systematic mechanism of transnational project failure in order to establish a foundation of prediction model.

This thesis is divided into five chapters listed as follow,

Chapter I -Introduction: Research, Background, and Motivation

Introducing the motivation and background of this research, and states the purpose of research. It also defines the subject and scope of research, as well as to compare with past research and set up the orientation of this research.

Chapter II -Sociological Phenomenon and Behavior Tendency

The first part of this research identifies that people from different countries carry different kind of practical conventions due to the differential background and environment in all levels from single person to entire organization giving various inputs into system, and creates corresponding combination of interfaces in projects. The purpose of this Chapter is to make a scientific inquiry about the formation of transnational building construction, and try to figure out the both end of sociological spectrum in order to locate the social tendency for different countries within the spectrum. And then figure out an appropriate social phenomenon to verify the sociological spectrum.

A sociological observation on conflict society and consensus society was engaged to reveal the differ-ent organizational behavior among societies. In order to verify such theory of sociological tendency, this research took investigation on legal structure, building regulation, and player liability as instru-ment to extinguish between collaborative tendency and adversarial tendency.

This chapter demonstrates the idea of sociological tendency spectrum to identify the variation of differential professional behavior tendencies. From the legal environment phenomenon, it clearly shows the both end of spectrum are majorly about the level of adversarial consciousness, and this differential tendency creates out two entirely different construction environments which shall carry out different construction methods respectively.

Chapter III -Mechanism of Modularity with Visualized Model

The second part of this research is to establish a scientific methodology to represent the mechanism of invisible dynamic task operation within entities and between entities, and also find a standard methodology to locate the affective interdependent task between entities which would turn out to be the critical paths among problematic module. By using the methodology, this chapter would like to verify the relationship between social tendency and construction method. And there are two risk taking tendencies were found in this chapter reflect to corresponding social background.

The entities from conflict society is more vulnerable against to uncertainty due to the players are more reluctant to accommodated omitted task by adversarial consciousness. Contrarily, the entities from consensus society are more robust against to uncertainty, and allow the system to be designed in an integration oriented system.

In order to verify the hypothesis above, this research has engaged a general overview on differential phenomenon of construction method tendencies between Japan and United States. The observation would be engaged with four different types of construction methods, precast concrete assembly, construction method at parapet area, expansion joint method at roof area, and multiplayer construction at window area.

This chapter indicated the understanding of the entity behavior, and also explored the mechanism of dynamic task flow among entities. Furthermore, the correlation between social tendencies and construction tendencies has been verified by analyzing on the corresponding task structure matrix. In other words, combine the mechanism of human behavior represented by Task Flow Model and the construction method carried out by Task Structure Matrix would provide us a scientific instrument to depict the abstract correlation between sociological tendency and construction tendency.

From the result of general observation and detail analysis, we could easily found that the consensus society tends to adopt the integrated approach in construction, and conflict society prefers the other way around.

Chapter IV -Application and Verification of Modularity Theory

This chapter started from taking an extented observation on the mechanism of tasks leading to project failure, and also the typical contractual operation currently used in construction industry to avoid such failure. And by following the mechanism of invisible dynamic task network demonstrated in Chapter 3, the purpose of this chapter is majorly to apply the theory and methodology established in previous chapter to actual cases with mechanism of failure and contractual system in order to verify the practicability of theory by comparing the task model of building system design in phases.

The first part of this chapter has demonstrated the mechanism of project failure and also the mitiga-tion strategies to facilitate the success of project. From the verification in the second part of this chapter, we may, therefore, reasonable conclude that interdependence among entities is the main source of risk to every construction project. However, a transnational construction project usually carries the interdependence without proper commitment device or culture convention.

In order to overcome the risk, the first verified mitigation strategy is using modular design approach which helps to reduce the interdependence among components as well as to entities. The second verified mitigation strategy is to use proper commitment device of contract to encourage the construction team absorbing more uncertainty under appropriate supervision. The third verified mitigation strategy is to rearrange the organization structure when the interdependence couldn't be effectively reduced by previous two methods.

Chapter V -Conclusion

This chapter is prepared to summarize the systematic theory of this research, and also prospect for the relevant research shall be engaged in the future to extend and consolidate the result.

建築構工法(Building Construction Method)は、特定の形状寸法の建築構成材を組み合わせて所定の性能を発揮させるという工学的側面だけでなく、如何なる範囲内容の生産作業を如何なる技術・技能・価値観をもっている者・組織が担当するかというマネジメント側面の二面から決定づけられる。マネジメント側面にかかわる諸要因によってBuilding Construction Methodが規定されるために、基本設計時点で実現しようとした建築の「ありよう」と、実際に生産された建築の「出来型」との間には差異が生じる。とりわけ、多様な国を出自とする組織が分担して建築生産に携わる多国籍プロジェクトにおいては、その差異が強くあらわれ、設計意図とは乖離した建築として仕上がってしまうことすらもしばしばおきてしまうことが、建築実務者の間では認識されている。しかしながら、「設計時点で描いた「ありよう」と「出来型」との差異がもたらす負の影響を如何に最小化するのか?」という課題、換言するならば「マネジメント側面にかかわる諸要因の作用がもたらす機能・性能・品質の不確実性の大きさを如何に評価し、その不確実性を如何に低減させるのか?」という課題に対して、必ずしも十分な学術的蓄積がなされてこなかった。

本論文は、多国籍プロジェクトを対象に、基本設計時点での「ありよう」と「出来型」との差異を生む諸要因とメカニズムを明らかにするとともに、その差異がもたらす機能・性能・品質の毀損を低減するためのプロセス・マネジメント手法にかかわる知見を得ることを目的にしたものである。

本論文は五章から成っている。序論である第一章に引き続き、第二章においては既往文献を参照しつつ建築生産に参画する主体の社会的挙動を社会学的枠組から説明・理解することを試み、挙動には異なる傾向があること、その傾向は対立的な関係の生じやすさの程度で説明できると解釈し、その対立的な関係の生みやすさにかかわる当事者の認識が建築構工法の差異を生むと推測するに至っている。

第三章においては、建築生産に参画する主体の社会的挙動と建築構工法との関係を記述するため、各主体がtaskを遂行し他主体のtaskへと繋いでいく過程、及びその過程に作用する諸要因をモデル化しようと試みている。筆者は、taskの流れの組み合わされ方(Task Flow Combination)に着目してTask Flow Modelを考案して考察を進めるとともに、Donald V. Stewardが考案したDependency Structure Matrixを下敷きに、TSM(Task Structure Matrix)を作成している。これは、行・列に建築構工法にかかわることがら(例 材料、許容誤差、高さ、幅、重量、形状など)を配して、ことがら同士の従属関係及び相互関係を表現(要素にドットを記入)することにより、どのようなtaskが発生するかを予測するものである。筆者は、interdependent task(すりあわせ作業)が限定されるTSMの様態、逆にそれらが多く発生する様態を概念的に示している。前者は対角要素付近に房状にドットが分布するもので、房となる範囲にかかわるTaskを一主体が担当することにより、Taskの範囲がモジュラー化され、interdependent taskを最小化することができる。換言すればモジュラー化の度合い(modularity)によってinterdependent taskの量は増減する。筆者は、日本及び米国における典型的なパラペットまわりの構工法、及び開口部まわりの構工法をTSMにより表現して分析し、米国の構工法の方がmodularityの高い構工法であることを明らかにしている。この事実から、建築生産主体間の関係が対立的関係に陥りやすい社会的傾向が高い状況ではmodularityの高い構工法が用いられる、という推測を提示している。なお、本論文における分析考察のキーコンセプトmodularityについては、吉田敏の学位論文などいくつかの先行研究があるが、TSMに含まれる種々のissuesを含めてmodularityを捉えようとしている点に本研究の新規性の一つがあると思われる。

第四章では、まず、作業分担及び構成材のインターフェースに発生しうる性能・品質欠陥の様態を整理したうえで、性能・品質欠陥を生むようなインターフェースに係わる不確実性を減じるための戦略について、TSMを用いて考察している。筆者は、生産に参加する主体間の対立的な関係が予測される状況においては、TSMの対角線上近傍にドットが集約されていくように構工法が変更されていく戦略が必要であるとし、TSMを用いた構工法検討・変更・決定の概念的手順を示している。この概念的手順の有効性を検証するため、筆者は多国籍プロジェクト3例における構工法決定プロセスを分析している。筆者はこれらのケーススタディ対象の実施設計段階における構工法の変更プロセスをTSMに基づいて記述し、これらの構工法の変更が、モジュラー化の度合い(modularity)を高めることにより、インターフェースに係わる不確実性を減じるための変更プロセスであったことを明らかにすることで、TSMを用いた構工法検討・変更・決定の手順が有効であることを示している。

第五章では、以上の推論・検証・考察を踏まえ、TSMを活用し社会的環境に応じて建築構工法のモジュラー化の度合い(modularity)を調整していくことが、建築の性能・品質にかかわる不確実性を減じていくことに有効であると結論づけるとともに、本論文の研究がさらに発展していくための諸課題を整理している。

以上のように、本論文は、建築生産にかかわる主体のもつ社会挙動特性や、他の主体との関係性などの条件によって、構工法の内容も異なりうることを論理だって説明するとともに、適用される構工法の品質・性能にかかわる不確実性を減じていくためのマネジメント戦略と、戦略を具現化するための分析ツールとしてのTSMに説得力を与えることに成功している。個別の構工法に対応してTSMを描くにあたって再現性が十分には担保されていないなど、内容にはさらに検討を要す点も多々含まれている、しかしながら、学術的基盤の乏しかった実務的課題について学術的考察・分析を行うための緒をつけたという挑戦性、萌芽性を勘案するならば、有益な学術的貢献をしていると認定できる。よって、本論文は博士(工学)の学位請求論文として一定水準に達していると判断できることから、本論文を博士(工学)の学位請求論文として合格と認める。