Deux situations de comportement égoïste des agents dans les réseaux de communication sont considérées dans le cadre de la théorie des jeux.La première situation concerne les réseaux de communication utilisant un routage décentralisé basé sur des agents autonomes. Nous étudions les propriétés de convergence des dynamiques de meilleures réponses dans un jeu de routage sur des liens parallèles. Le jeu implique un nombre fini d'agents, chacun décidant comment son trafic est routé sur les liens de manière à minimiser son propre coût. Nous proposons l'utilisation du rayon spectral généralisé des matrices Jacobiennes de l'opérateur de meilleure réponse pour démontrer la convergence.La seconde situation apparaît dans les réseaux tolérants aux délais dont l'objectif est de permettre la communication dans des environnements où la connectivité n'est qu'intermittente et où les délais de communication peuvent être très longs. Nous proposons tout d'abord un mécanisme d'incitation basé sur une récompense pour convaincre les noeuds mobiles de relayer les messages, et analysons l'influence de l'information donnée par la source (nombre de copies du message, âge de ces copies) aux relais sur le prix à payer pour transmettre le message. Nous considérons ensuite un modèle dans lequel la source propose une récompense fixe. Les noeuds mobiles peuvent alors décider d'accepter ou non le message, et s'ils l'acceptent, peuvent ensuite à tout moment décider de l'abandonner. Nous modélisons l'interaction entre les noeuds mobiles sous la forme d'un jeu stochastique partiellement observable et analysons les politiques optimales pour les relais. / This thesis focuses on the issues related to the selfish behavior of the agents in the communication networks. We are particularly interested in two situations in which these issues arise and we address game-theoretical framework to study them.The first situation relates to communication networks using a distributed routing based on autonomous agents. Compared to a centralized routing, this type of routing offers significant advantages in terms of scalability, ease of deployment or robustness to failures and environmental disturbances. We investigate the convergence properties of the sequential best-response dynamics in a routing game over parallel links. The game involves a finite number of routing agents each of which decides how much flow to route on each of the links with the objective of minimizing its own costs. For some particular cases (e.g., two players), the convergence of the best-response dynamics can be proved by showing that this game has a potential function. For other cases, a potential function has remained elusive. We propose the use of non-linear spectral radius of the Jacobian of the best-response dynamics as an alternative approach to proving its convergence.The second situation occurs in Delay Tolerant Networks (DTNs) that have been the subject of intensive research over the past decade. DTN has an idea to support communication in environments where connectivity is intermittent and where communication delays can be very long. We focus on game-theoretic models for DTNs. First, we propose an incentive mechanism to persuade selfish mobile nodes to participate in relaying messages, and investigate the influence of the information given by the source (number of existing copies of the message, age of these copies) to the relays on the rewards proposed. For static information polices, that is the same type of information given to all the relays, it is shown that the expected reward paid by the source is independent of the policy. However, the source can reduce the reward by dynamically adapting the type of information based on the meeting times with the relays. For the particular cases, we give some structural results of the optimal adaptive policy. Next, we consider the model where the source proposes a fixed reward. The mobile relays can decide to accept or not the packet and then to drop the packet in the future. This game can be modelled as a partially-observable stochastic game. For two relays, we have shown that the optimal policies for the relays relates to the threshold type.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19123号 / 情博第569号 / 新制||情||100(附属図書館) / 32074 / 京都大学大学院情報学研究科数理工学専攻 / (主査)教授 山下 信雄, 教授 中村 佳正, 教授 田中 利幸 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Process mining is the application of data science technologies on transactional business data to identify or monitor processes within an organization. The analyzed data often originates from process-unaware enterprise software, e.g. Enterprise Resource Planning (ERP) systems. The differences in data management between ERP and process mining systems result in a large fraction of ambiguous cases, affected by convergence and divergence. The consequence is a chasm between the process as interpreted by process mining, and the process as executed in the ERP system. In this thesis, a purchasing process of an SAP ERP system is used to demonstrate, how ERP data can be extracted and transformed into a process mining event log that expresses ambiguous cases as accurately as possible. As the content and structure of the event log already define the scope (i.e. which process) and granularity (i.e. activity types), the process mining results depend on the event log quality. The results of this thesis show how the consideration of case attributes, the notion of a case and the granularity of events can be used to manage the event log quality. The proposed solution supports continuous event extraction from the ERP system. / Process mining är användningen av datavetenskaplig teknik för transaktionsdata, för att identifiera eller övervaka processer inom en organisation. Analyserade data härstammar ofta från processomedvetna företagsprogramvaror, såsom SAP-system, vilka är centrerade kring affärsdokumentation. Skillnaderna i data management mellan Enterprise Resource Planning (ERP)och process mining-system resulterar i en stor andel tvetydiga fall, vilka påverkas av konvergens och divergens. Detta resulterar i ett gap mellan processen som tolkas av process mining och processen som exekveras i ERP-systemet. I denna uppsats används en inköpsprocess för ett SAP ERP-system för att visa hur ERP-data kan extraheras och omvandlas till en process mining-orienterad händelselogg som uttrycker tvetydiga fall så precist som möjligt. Eftersom innehållet och strukturen hos händelseloggen redan definierar omfattningen (vilken process) och granularitet (aktivitetstyperna), så beror resultatet av process mining på kvalitén av händelseloggen. Resultaten av denna uppsats visar hur definitioner av typfall och händelsens granularitet kan användas för att förbättra kvalitén. Den beskrivna lösningen stöder kontinuerlig händelseloggsextraktion från ERPsystemet.

Thesis (PhD (Mathematics))--University of Stellenbosch, 2010. / Contains bibliography. / ENGLISH ABSTRACT: See full text for summary. / AFRIKAANSE OPSOMMING: Sien volteks vir opsomming

Studies conducted for the US have found a positive effect of human capital endowments on employment growth, with human capital endowments diverging at the same time. In contrast, studies for European countries have found convergence of human capital endowments. This paper tests these relationships for 99 Austrian districts for the observation period 1971-2011 by estimating how the presence of high-skilled employment affects total, low-skilled and high-skilled employment growth. To this end, OLS, fixed effects and first difference regressions are estimated. The results show continuous convergence of high-skilled employment which, however, slowed downed significantly since the 1990s. In contrast to previous studies, evidence for positive effects of high-skilled on total and low-skilled employment is only weak and varies over time. Furthermore, the results show that total and high-skilled employment in suburban areas grew faster than in other regions, while districts which bordered the Eastern Bloc were disadvantaged. Nevertheless, spatial neighbourhood effects within Austria are only weak. (authors' abstract) / Series: Working Papers in Regional Science

This thesis investigates different methods that can be used for analyzing network performance and,ultimately, can be used for measuring the convergence time of ring coupled networks. As of today,many networks are often run with extra links, serving as backup links in case any that of the mainlinks would go down. To operate networks with backup links in layer 2 and layer 3, specific re-routing protocols such as RIP and OSPF are used in order to calculate a feasible path through anetwork when a network state changes. Depending on different implementations of the protocolsand the hardware used, the convergence times can vary substantially, which means measuring thenetwork performance is a very important part when developing a network solution. To executenetwork tests, a packet engine suite is used consisting of a network traffic generator that is used forcreating a packet stream, as well as a traffic receiver that fetches the packets sent. Various types ofengines can be used including Linux based, real-time operating systems based and bare-metal basedsolutions. From these different types of engines, a few tools are chosen and investigated on differentproperties including performance and usability. It was found that Tshark (Linux, RT-Linux based),USPI (Raspberry Pi bare metal), FreeRTOS (Raspberry Pi based), Arduino and PKTgen (Linuxkernel based) were the most suitable approaches to be used for testing. The test parameters includetesting the gaps between packets, maximum jitter, average jitter and packets sent per second. Thesetests revealed that an IXIA solution was slightly more accurate when used as a receiving end sinceit produced less jitter, however this difference could only be noticed in a micro second range. Itwas also revealed that it produced slightly less jitter than the other packet generators, also here onlynoticeable in a microsecond range. Thus it can be concluded that IXIA is not much superior any ofthe close to hardware solutions. The executed network tests revealed that the Westermo developedlayer 2 protocol FRNT generated less network convergence time and less packet losses than thecommonly used RSTP protocol. Similar tests against the layer 3 protocols revealed that RIP wasmuch faster than OSPF and it also lost less packets. Finally it is concluded that there is no needto buy an expensive network testing suite to test the convergence time of a network. Instead, anetwork testing suite can be developed with minimal funding.

This paper seeks to investigate the current state of market integration among European electricity day-ahead spot prices. We provide reasoning that market integration brings about benefits, such as lower average prices and increased welfare from allocative efficiency. Yet, price convergence leads to higher prices in the low-price market and to lower prices in the high-price market, which creates winners and losers and thus makes the political implementation of market integration cumbersome. In our empirical analysis, we utilize a large sample of hourly spot prices of 25 European markets for the period 01.01.2010-30.06.2015 and combine it with other relevant data such as interconnector capacities and the existence of market coupling. Firstly, empirical results from cointegration analysis indicate that market integration increased from 2010 to 2012 but then declined until 2015, most likely due to increased feed-in from intermittent renewables. Secondly, we empirically assess the speed of adjustment from price shocks and reach the conclusion that the resulting efficiency of integration is rather modest. In general, our findings suggest that integration among European electricity markets has a large potential for improvements from additional capacity investments and further promotion of market coupling. (authors' abstract) / Series: Department of Economics Working Paper Series

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The international marketing literature has a common assumption that consumers across countries are becoming more similar in their consumption behavior over time. However, this assumption of global convergence of consumer spending has not been empirically tested in the literature. In this dissertation, we examine the convergence hypothesis across a heterogeneous set of countries and multiple product categories. In the first essay, we develop a conceptual framework of convergence of consumer spending behavior. In the second essay, we empirically test whether convergence is observed across markets and product categories over time. Finally, in the third essay, we investigate the effect of global convergence of consumer spending on market concentration and firms’ market shares. Using the four-firm concentration ratio, we compute the market concentration by industry in each market to investigate the effect of convergence on market concentration. We also examine the effect of convergence on market shares of individual firms, considering the moderating effects of country of origin, country of operation, and the degree of internationalization of the firm. We model the dependent variables, market concentration and market shares, using the fractional logit model. Our results show that there is an overall convergence trend across product categories and countries over time. Moreover, we find that convergence increases the market shares of the largest firms in a market. The findings of this study have theoretical and managerial implications on major marketing areas including global marketing strategy, internationalization, and market segmentation.

Thesis (MBA) -- Stellenbosch University, 2007. / Today we face a reality where existing power relations concerning economical, political and cultural institutions and forces are changing. It is about more than just the right to use a technology in itself; it is a matter of having, or not having, access to infonnation and knowledge. The use of information and communications technology (lCT) is an important and powerful tool when it comes to distributing and sharing these resources (Bridges.arg, 2006). The unequal distribution of and the differences in the possibility to use rer effectively are often referred to by the term digital divide (DDN, 2006). Does this sound quite pessimistic? However, a change is taking place since all countries on earth from the richest to the poorest are actually increasing their Ier usage. The problem is that the developed countries are using convergence (three separate communication sectors: information technology, telecommunications and broadcasting merging to become a single communication service sector) to escalate their access to and use of ICf at a much higher speed, which in fact widens the digi tal divide instead of shrinking it (Bridges.org, 2006). Today no country can afford to neglect investments in ICf if it wishes to raise its living standards or to prevent it from being left behind as other countries exploits the possibilities of ICf. Why is ICf considered to be an effective tool for bridging the international digita1 divide? On the United Nations Development Programme's website one can read: " .. .ICf is an increasi ngly powerful tool for participating in global markets; promoting political accountability; improving the delivery of basic services; and enhancing local development opportunities" (UNOP, 2003). These aspects can be of great importance for developing countries in their effort to gain economic development and improvements. Furthermore, it is also a question about every human's right to have access to infonnation (Sida, 2004). According to Steve Case (AOL Time Warner, Chainnan of the Board) every decade has some word associated with it. In the 'SOs, it was the PC. In the '90s, it was the Internet. For the rest of this decade, the key word is going to be convergence (Thompson, 2003). In Namibia a digital divide exists between income groups as well as between the country's rural and urban population. Namibia is sti ll far from providing equal access to information, but Namibia is well positioned to deploy ICf to its advantage. Namibia has a functional telecommunication infrastructure, political stability and an attractive economic environment for investors. However. the geographic and social challenges of Namibia require innovative approaches and considerable effort. Competition and convergence will improve the situation. recommended to expand the set of potential drivers and specifically focus on the relation between convergence and economic growth.