Wireless network technology has advanced to the point that it is possible to use Internet connectivity to perform job tasks while moving in a city. We simulate and experimentally evaluate Dunham&rsquo / s Kangaroo Transaction (KT) model, and a modified version of it. Our results show that the modified-KT model does not have much communication overhead (although more than the original KT model) and it is more resilient to failures of base stations.

Cette thèse est composée de quatre chapitres et analyse une régularité empirique très mal connue et très peu analysée : les « formes organisationnelles plurielles ». Dans le premier chapitre, j’examine les diverses tentatives de théoriser les formes plurielles et comment ce domaine a évolué au fil du temps. Cela me permet d’identifier deux variables qu’on retrouve au cœur des idées exprimées dans ces tentatives pour expliquer l’existence et la stabilité des formes plurielles : la spécificité des actifs ainsi que les facteurs d’incertitude. Néanmoins, ces variables sont restées très mal explorées, ce qui pointe la nécessité de nouvelles contributions théoriques sur ce sujet. Dans le deuxième chapitre, je cherche à comprendre ce qui explique la variété des formes plurielles. Je propose un modèle théorique intégrant la spécificité des actifs et l'incertitude pour pronostiquer l’existence des formes plurielles et non plurielles. Ensuite, je souligne que les formes plurielles sont hétérogènes et je construis des hypothèses mettant en relation différents types d’incertitude avec des formes plurielles différentes. Dans les deux chapitres suivants, le modèle théorique et les hypothèses sont confrontés à des données empiriques qualitatives. Le troisième chapitre confronte le modèle théorique à une étude de cas clinique menée au sein d’une entreprise, l’entreprise Korin (Brésil), qui produit et vend divers produits bios. Enfin dans le chapitre quatre, le modèle théorique et les hypothèses sont confrontés à des données recueillies à partir d’une enquête sur l’approvisionnement en ‘inputs’ auprès de 24 entreprises opérant dans le secteur agricole brésilien. Je trouve dans ces deux articles des concordances fortes à l’appui de mon modèle et des hypothèses que j’en ai dérivées, ce qui ouvre la voie à de nouvelles recherches. / This dissertation is composed of four chapters and addresses an empirical regularity about which very little is known: “plural forms”. In the first chapter, I intend to verify what has been theorized about plural forms and how this field has evolved over time. I identified two variables that underlie most of the theoretical explanations for the existence and stability of plural forms: asset specificity and uncertainty. However, these variables are very seldom explored, which points towards the need for novel contributions. In the second chapter, I am concerned with explaining the variety of plural form manifestations. I built a theoretical model integrating asset specificity and uncertainty to predict plural and non-plural forms. Next, I stressed that plural forms are heterogeneous and built hypotheses relating different types of uncertainty to different types of plural forms. In the next two chapters, I empirically confront my theoretical model and hypotheses with qualitative data. In the third chapter, I confront my model by performing an embedded clinical case study on the Korin company (in Brazil), which produces and commercializes multiple organic products; while in the final chapter, I intend to empirically confront both my theoretical model and my hypotheses and survey the procurement of inputs by 24 companies operating in the Brazilian Agribusiness sector. I find support for my model and for my hypotheses on both of these papers, indicating a path for further analyses.

This paper analyzes the tax effects of the German real estate transfer tax (RETT). While the vast majority of single-family houses in Germany are owner-occupied, apartments are usually held by private and incorporated investors. For this reason, we conducted a regression analysis to determine the effects of increasing RETT on the number and the prices of transactions separately for these two market segments. Our findings suggest that increasing the RETT by 1% is associated with a decline in transactions by 0.23% for single-family houses, but with no significant effect on the prices of traded houses. Conversely, for apartments, we find no significantly negative effects on the transactions, but the price effect of the RETT tends to be negative. Finally, for vacant lots, we find even larger quantity effects than for singlefamily houses suggesting roughly an elasticity of -1. The results for this specific market segment indicate that the government operates near the top of a Laffer curve. / Series: WU International Taxation Research Paper Series

La fin des années 1970 dans la commune de N'Toum au Gabon est marquée par l'implantation d'une des plus importantes entreprises du pays dont la spécialité est l'extraction et la fabrication de clinker. Toutefois, l'activité de l'entreprise CIMGABON a des conséquences négatives qui se traduisent par une modification considérable du paysage environnemental. C'est pour remédier à cette situation commune à plusieurs entreprises du pays que le Gabon a opté, depuis la fin des années 1990, sous la pression des instances internationales notamment, pour une politique environnementale, mettant désormais au centre de l'action, les acteurs (politiques, sociaux, environnementaux....) pris dans une logique de co-gestion, comme coondition nécessaire à une meilleure gestion de l'environnement. La participation a ainsi permis de donner une légitimité à des acteurs souvent laissés pour compte. Cependant, ces acteurs rencontrent de nombreuses difficultés à se constituer en tant qu'entités à part entière de cette gestion environnementale, cette dernière demeurant donc chaotique. / The end of 1970s in the municipality of N'Toum in the Gabun is marked by the setting-up of one of the most important ompanies of the country the specialityof which is the extraction and the manufacturing of clinker. However, the activity of the company CIMGABON has negative consequences which are translated by a considerable modification of the environmental landscape. It is to remedy this situation common to several companies of the country that Gabon opted, since the end of 1990s, under the pressure of the international authorities in particular, for an environmental policy, putting henceforth in the center of the action, the actors (political, social, environmental) taken in a logic of co-management, as condition necessary for a better management of the environment. The participation in so allowed to give a legitimacy to often rejected actors. However, these actors meet numerous difficulties constituting as full entities of this environmental management, the latter remaining thus chaotic.

Subject of thesis are private transaction costs of public procurement. It's estimation of money spent by firms during public procurement tenders and seeking out factors influencing these costs. Theoretical frame of this thesis is between transaction cost economy and public procurement economy. Main result is estimation of private transaction cost of one offer in 0,44% of final contract prize. Estimation of whole private transaction costs of public procurement in Czech republic for 2011 is almost 9 milliard CZK. Important factors found out by econometric analysis and correlative coefficients are size of firm and contract value.

Ce travail de thèse propose d’interroger la place des loisirs de chasse, de pêche, de cueillette et d’observation naturaliste dans la préservation des espaces naturels de l’estuaire de la Seine. Le cadre conceptuel s’appuie sur la sociologie du loisir nord-américaine pour traiter ces activités selon la Perspective des Loisirs Sérieux. À travers une méthodologie qui mêle l’ethnographie, l’entretien récit de vie et le questionnaire, ces loisirs sont présentés comme le support de conflits mais aussi d’engagements, liés à l’étude, à la gestion et à la valorisation de la nature. L’analyse lie l’immersion dans l’environnement et la pratique de la prédation avec la construction de convictions écologiques d’ordre sociopolitique. La mise en cohérence de ces convictions est assurée par des passeurs qui font usage du loisir comme d’un outil de transaction sociale : il est un support de communication utilisé pour mettre en réseau les différents acteurs institutionnels et associatifs qui s’investissent dans la préservation de la nature. / This thesis proposes to question hunters, anglers, gatherers and wildlife watchers as part of the network which preserve the natural spaces around the river Seine estuary. The conceptual framework is based on North American sociology of leisure. These activities are considered according to the Serious Leisure Perspective. Through a methodology that combines ethnography, interviews and survey, these activities are described as support for volunteering.The analysis links the practice of predation with ecological convictions. Leisure is also used as a communication medium and help creating a consistent network to preserve nature.

Les travaux présentés dans ce mémoire étudient les problématiques transactionnelles posées par le développement des éco-parcs industriels (EPI). Nos travaux visent donc à fournir une analyse économique des synergies éco industrielles (substitution de ressource, mutualisation d'infrastructures) afin de compléter les approches techniques principalement développées en sciences de l'ingénieur. Notre unité d'analyse sera donc les transactions. Nous proposons une typologie des pratiques de synergies éco-industrielles ainsi qu'une représentation de leur processus de mise en oeuvre. Nous analysons le cas de l'EPI Green Valley (France). Nous caractérisons et mettons en perspective son développement et les principaux facteurs ayant affecté son processus de déploiement. Ensuite, en faisant appel à des arguments issus de l'économie des coûts de transaction, nous proposons l'usage de contrats de long terme complexes pour organiser les transactions associées aux SI. En conséquence, un cadre de conception des contrats incluant des clauses spécifiques (tarification, pénalités, garanties) est proposé de manière à tarifer les flux et à partager le risque. Dans une dernière partie, nous étudions les décisions d'investissement en capacités mutualisées. / This thesis report aims at addressing transactional issues raised by the undertaking of eco-industrial parks (EIP) development. The economics of eco-industrial synergies (resource "flow" substitution and infrastructure/service "capacity" sharing) is investigated so as to complement existing engineering-oriented approaches. A focus is made on industrial stakeholders' interplay in industrial symbiosis (IS) and their strategic decisionmaking in terms of investment and contracting practices. First, a survey of practices actually observed in EIPs in function is conducted through a literature review. A taxonomy of eco-industrial synergies is thus proposed and an IS implementation process representation is derived. Then we conduct a case study on the GreenValley eco-industrial park (France) Then, from economic arguments (transaction costs) we advocate the use of long term contracting in organizing IS related transactions. Following this, a contract design framework including specific provisions (tarification, penalties, warranties) is proposed in order to perform pricing of flows exchanges and risk sharing. In a last part, investment decisions in shared capacities is studied using economic modelling both in cooperative and non-cooperative game setting. Key economic parameters (size, back-up costs, scaling factor) and behavioral decisions (investment, commitment) are described and uncertainty is treated in two different approaches.

This research study investigates the relationship between ambiguity, litigation risk, and auditor decision-making. In addition, this study investigates how auditor trust of his or her client may change these relationships. It is important to investigate the relationships of ambiguity, litigation risk, and client trust to auditor decision-making because auditors face these factors on a regular basis. This research uses a 2x2 experiment to investigate auditor reaction to ambiguity and litigation risk. The first factor, ambiguity is operationalized as auditor reaction to potential real transaction earnings management (low ambiguity) and potential accrual transaction earnings management (high ambiguity). The second factor, litigation risk is operationalized through an income increasing (high) or income decreasing (low) earnings management attempt. Auditors were given company background information, selected account information, and comparative financial statements and then asked to state the likelihood of material misstatement in the financial statements as a whole and the sales, selling and marketing expenses, research and development expenses, and general and administrative expenses individual accounts. The ambiguity manipulation was imbedded in the description of the research and development account while the litigation risk factor was imbedded in the comparative financial statements. The findings indicate that the subjects reported a relatively high likelihood of material misstatement of research and development expenses regardless of the earnings management method. The findings further indicate that when a real earnings management transaction was present, auditors rated the likelihood of material misstatement in sales and the financial statements as a whole higher than when an accrual earnings management transaction is present. Additionally, when the subject group is limited to individuals working for Big-4 and National non Big-4 firms the auditors assessed the likelihood of material misstatement in the financial statements as a whole, sales, selling and marketing expenses, and general and administrative expenses significantly higher when a real earnings management transaction is present than when an accrual earnings management transaction is present. The lawsuit risk factor was not found to be significant in any of the primary analyses. The research also explores the relationship between an auditor's trust of the client and the likelihood of material misstatement assessment. Auditors completed the Kerler and Killough trust scale to measure trust of the experimental client. The findings report that as external auditor experience increases, auditor trust of the client decreases. However, this decrease in trust does not significantly affect the likelihood of material misstatement assessment. This research study is the first step in developing an understanding of the relationship between ambiguity, risk, trust, and auditor decision-making. The findings indicate that auditors do use information about potential earnings management in one account when evaluating the likelihood of material misstatements in other accounts. Future research should develop an understanding about whether auditors should take these factors into consideration in the planning stages of the audit. / Ph. D.

With the recent technological developments in last few decades, there is a notable shift in the way business/consumer transactions are conducted. These transactions are usually triggered over the internet and transactional systems working in the background ensure that these transactions are processed. The majority of these transactions nowadays fall in Online Transaction Processing (OLTP) category, where low latency is preferred characteristic. In addition to low latency, OLTP transaction systems also require high service continuity and dependability. Replication is a common technique that makes the services dependable and therefore helps in providing reliability, availability and fault-tolerance. Deferred Update Replication (DUR) and Deferred Execution Replication (DER) represent the two well known transaction execution models for replicated transactional systems. Under DUR, a transaction is executed locally at one node before a global certification is invoked to resolve conflicts against other transactions running on remote nodes. On the other hand, DER postpones the transaction execution until the agreement on a common order of transaction requests is reached. Both DUR and DER require a distributed ordering layer, which ensures a total order of transactions even in case of faults. In today's distributed transactional systems, performance is of paramount importance. Any loss in performance, e.g., increased latency due to slow processing of client requests, may entail loss of revenue for businesses. On one hand, the DUR model is a good candidate for transaction processing in those systems in case the conflicts among transactions are rare, while it can be detrimental for high conflict workload profiles. On the other hand, the DER model is an attractive choice because of its ability to behave as independent of the characteristics of the workload, but trivial realizations of the model ultimately do not offer a good performance increase margin. Indeed transactions are executed sequentially and the total order layer can be a serious bottleneck for latency and scalability. This dissertation proposes novel solutions and system optimizations to enhance the overall performance of replicated transactional systems. The first presented result is HiperTM, a DER-based transaction replication solution that is able to alleviate the costs of the total order layer via speculative execution techniques. HiperTM exploits the time that is between the broadcast of a client request and the finalization of the order for that request to speculatively execute the request, so to achieve an overlapping between replicas coordination and transactions execution. HiperTM proposes two main components: OS-Paxos, a novel total order layer that is able to early deliver requests optimistically according to a tentative order, which is then either confirmed or rejected by a final total order; SCC, a lightweight speculative concurrency control protocol that is able to exploit the optimistic delivery of OS-Paxos and execute transactions in a speculative fashion. SCC still processes write transactions serially in order to minimize the code instrumentation overheads, but it is able to parallelize the execution of read-only transactions thanks to its built-in object multiversion scheme. The second contribution in this dissertation is X-DUR, a novel transaction replication system that addressed the high cost of local and remote aborts in case of high contention on shared objects in DUR based approaches, due to which the performance is adversely affected. Exploiting the knowledge of client's transaction locality, X-DUR incorporates the benefits of state machine approach to scale-up the distributed performance of DUR systems. As third contribution, this dissertation proposes Archie, a DER-based replicated transactional system that improves HiperTM in two aspects. First, Archie includes a highly optimized total order layer that combines optimistic-delivery and batching thus allowing the anticipation of a big amount of work before the total order is finalized. Then the concurrency control is able to process transactions speculatively and with a higher degree of parallelism, although the order of the speculative commits still follows the order defined by the optimistic delivery. Both HiperTM and Archie perform well up to a certain number of nodes in the system, beyond which their performance is impacted by limitations of single leader-based total-order layer. This motivates the design of Caesar, the forth contribution of this dissertation, which is a transactional system based on a novel multi-leader partial order protocol. Caesar enforces a partial order on the execution of transactions according to their conflicts, by letting non-conflicting transactions to proceed in parallel and without enforcing any synchronization during the execution (e.g., no locks). As the last contribution, this dissertation presents Dexter, a replication framework that exploits the commonly observed phenomenon such that not all read-only workloads require up-to-date data. It harnesses the application specific freshness and content-based constraints of read-only transactions to achieve high scalability. Dexter services the read-only requests according to the freshness guarantees specified by the application and routes the read-only workload accordingly in the system to achieve high performance and low latency. As a result, Dexter framework also alleviates the interference between read-only requests and read-write requests thereby helping to improve the performance of read-write requests execution as well. / Ph. D.

Multidatabases are being actively researched as a relatively new area in which many aspects are not yet fully understood. This area of transaction management in multidatabase systems still has many unresolved problems. The problem areas which this dissertation addresses are classification of multidatabase systems, global concurrency control, correctness criterion in a multidatabase environment, global deadlock detection, atomic commitment and crash recovery. A core group of research addressing these problems was identified and studied. The dissertation contributes to the multidatabase transaction management topic by introducing an alternative classification method for such multiple database systems; assessing existing research into transaction management schemes and based on this assessment, proposes a transaction processing model founded on the optimal properties of transaction management identified during the course of this research. / Computing / M. Sc. (Computer Science)