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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Large-Scale Information Acquisition for Data and Information Fusion

Johansson, Ronnie January 2006 (has links)
The purpose of information acquisition for data and information fusion is to provide relevant and timely information. The acquired information is integrated (or fused) to estimate the state of some environment. The success of information acquisition can be measured in the quality of the environment state estimates generated by the data and information fusion process. In this thesis, we introduce and set out to characterise the concept of large-scale information acquisition. Our interest in this subject is justified both by the identified lack of research on a holistic view on data and information fusion, and the proliferation of networked sensors which promises to enable handy access to a multitude of information sources. We identify a number of properties that could be considered in the context of large-scale information acquisition. The sensors used could be large in number, heterogeneous, complex, and distributed. Also, algorithms for large-scale information acquisition may have to deal with decentralised control and multiple and varying objectives. In the literature, a process that realises information acquisition is frequently denoted sensor management. We, however, introduce the term perception management instead, which encourages an agent perspective on information acquisition. Apart from explictly inviting the wealth of agent theory research into the data and information fusion research, it also highlights that the resource usage of perception management is constrained by the overall control of a system that uses data and information fusion. To address the challenges posed by the concept of large-scale information acquisition, we present a framework which highlights some of its pertinent aspects. We have implemented some important parts of the framework. What becomes evident in our study is the innate complexity of information acquisition for data and information fusion, which suggests approximative solutions. We, furthermore, study one of the possibly most important properties of large-scale information acquisition, decentralised control, in more detail. We propose a recurrent negotiation protocol for (decentralised) multi-agent coordination. Our approach to the negotiations is from an axiomatic bargaining theory perspective; an economics discipline. We identify shortcomings of the most commonly applied bargaining solution and demonstrate in simulations a problem instance where it is inferior to an alternative solution. However, we can not conclude that one of the solutions dominates the other in general. They are both preferable in different situations. We have also implemented the recurrent negotiation protocol on a group of mobile robots. We note some subtle difficulties with transferring bargaining solutions from economics to our computational problem. For instance, the characterising axioms of solutions in bargaining theory are useful to qualitatively compare different solutions, but care has to be taken when translating the solution to algorithms in computer science as some properties might be undesirable, unimportant or risk being lost in the translation. / QC 20100903
32

Three Essays on the Role of Information and Financial Literacy in Crowdinvesting

Hemaidan, Nader 21 September 2018 (has links)
Diese kumulative Dissertation untersucht die Rolle von Informationen und Finanzkompetenz im deutschen Crowdinvesting-Markt. Die erste Studie erforscht den Zusammenhang zwischen dem Umfang der von Start-Ups auf Companisto veröffentlichen Informationen und dem Investitionsverhalten von Crowdinvestoren auf Basis proprietärer Nutzer-level Companisto-Daten. Meine Ergebnisse deuten darauf hin, dass (unerfahrene) private Investoren, im Gegensatz zu institutionellen Investoren, auch „weiche“ Informationen im Rahmen ihrer Investitionsentscheidungen berücksichtigen. Meine zweite Studie untersucht das tatsächliche Informationsverhalten von Crowdinvestoren im Vorfeld von Investitionen auf Basis von Nutzer-level Google Analytics-Daten. Meine Ergebnisse suggerieren, dass Investoren einen Großteil der von Start-ups bereitgestellten Informationen im Vorfeld von Investitionen ignorieren. Darüber hinaus zeige ich auf, dass das Informationsverhalten von Investoren mit den demografischen Merkmalen, der Crowdinvesting-Erfahrung und den (durchschnittlichen) Investitionsbeträgen von Investoren zusammenhängt. Meine Ergebnisse deuten zudem darauf hin, dass Investoren beim Vorliegen potentieller Indikatoren für die Qualität eines Start-ups bzw. bei weniger riskanten Investitionen, weniger Information akquirieren. In meiner dritten Studie, welche ich gemeinsam mit Joachim Gassen durchführe, untersuche ich den kausalen Effekt einer Online-Finanzschulung auf das Informations- und Investitionsverhalten von Crowdinvestoren im Rahmen eines Feldexperiments auf Companisto. Während das Experiment noch nicht abgeschlossen ist, motiviert der in dieser Dissertation enthaltene Zwischenbericht die zugrundeliegende Forschungsfrage und beschreibt das Forschungsdesign. Die vorläufigen Ergebnisse zeigen auf, dass Crowdinvestoren im Vergleich zu repräsentativen Stichproben der Gesamtpopulation, welche vergleichbaren Studien zugrunde liegen, ein signifikant höheres Maß an finanzieller Grundkompetenz aufweisen. / This cumulative Ph.D. thesis investigates the role of information and financial literacy in the German crowdinvesting market. Using proprietary investor-level data from Companisto, one of the largest German crowdinvesting portals, the first paper explores how the magnitude of start-ups’ disclosures on Companisto is associated with crowdinvestors’ investment behavior. My findings suggest that the investment decisions by both retail and institutional crowdinvestors are positively associated with the magnitude of start-ups’ voluntary disclosures. However, while start-ups’ ‘soft’ disclosures seem to play a role in the decision-making of (inexperienced) retail investors, they appear to be irrelevant for the investment decisions of institutional investors. My second thesis paper uses investor-level Google Analytics data to explore investors’ actual information acquisition prior to investing. My results indicate that crowdinvestors tend to neglect a substantial fraction of start-ups’ disclosures before investing. Moreover, I show that investors’ information acquisition varies with their demographics, their level of crowdinvesting experience as well as their (average) investment amounts. My findings further suggest that investors acquire less information in the presence of potential signals of start-up quality and (thus) in cases where the investment appears to be less risky. In my third paper, which is co-authored by Joachim Gassen, I study the causal effect of online financial training on crowdinvestors’ information and investment behavior by conducting a field experiment on Companisto. While the experiment is still ongoing, the interim report included in my thesis motivates the overall research question and explains the research design. Our preliminary results indicate that, compared to survey samples representative for the overall population, crowdinvestors exhibit a significantly higher level of ‘basic’ financial literacy.
33

Essays in economics of information

Gendron-Saulnier, Catherine 04 1900 (has links)
Cette thèse est une collection de trois articles en économie de l'information. Le premier chapitre sert d'introduction et les Chapitres 2 à 4 constituent le coeur de l'ouvrage. Le Chapitre 2 porte sur l’acquisition d’information sur l’Internet par le biais d'avis de consommateurs. En particulier, je détermine si les avis laissés par les acheteurs peuvent tout de même transmettre de l’information à d’autres consommateurs, lorsqu’il est connu que les vendeurs peuvent publier de faux avis à propos de leurs produits. Afin de comprendre si cette manipulation des avis est problématique, je démontre que la plateforme sur laquelle les avis sont publiés (e.g. TripAdvisor, Yelp) est un tiers important à considérer, autant que les vendeurs tentant de falsifier les avis. En effet, le design adopté par la plateforme a un effet indirect sur le niveau de manipulation des vendeurs. En particulier, je démontre que la plateforme, en cachant une partie du contenu qu'elle détient sur les avis, peut parfois améliorer la qualité de l'information obtenue par les consommateurs. Finalement, le design qui est choisi par la plateforme peut être lié à la façon dont elle génère ses revenus. Je montre qu'une plateforme générant des revenus par le biais de commissions sur les ventes peut être plus tolérante à la manipulation qu'une plateforme qui génère des revenus par le biais de publicité. Le Chapitre 3 est écrit en collaboration avec Marc Santugini. Dans ce chapitre, nous étudions les effets de la discrimination par les prix au troisième degré en présence de consommateurs non informés qui apprennent sur la qualité d'un produit par le biais de son prix. Dans un environnement stochastique avec deux segments de marché, nous démontrons que la discrimination par les prix peut nuire à la firme et être bénéfique pour les consommateurs. D'un côté, la discrimination par les prix diminue l'incertitude à laquelle font face les consommateurs, c.-à-d., la variance des croyances postérieures est plus faible avec discrimination qu'avec un prix uniforme. En effet, le fait d'observer deux prix (avec discrimination) procure plus d'information aux consommateurs, et ce, même si individuellement chacun de ces prix est moins informatif que le prix uniforme. De l'autre côté, il n'est pas toujours optimal pour la firme de faire de la discrimination par les prix puisque la présence de consommateurs non informés lui donne une incitation à s'engager dans du signaling. Si l'avantage procuré par la flexibilité de fixer deux prix différents est contrebalancé par le coût du signaling avec deux prix différents, alors il est optimal pour la firme de fixer un prix uniforme sur le marché. Finalement, le Chapitre 4 est écrit en collaboration avec Sidartha Gordon. Dans ce chapitre, nous étudions une classe de jeux où les joueurs sont contraints dans le nombre de sources d'information qu'ils peuvent choisir pour apprendre sur un paramètre du jeu, mais où ils ont une certaine liberté quant au degré de dépendance de leurs signaux, avant de prendre une action. En introduisant un nouvel ordre de dépendance entre signaux, nous démontrons qu'un joueur préfère de l'information qui est la plus dépendante possible de l'information obtenue par les joueurs pour qui les actions sont soit, compléments stratégiques et isotoniques, soit substituts stratégiques et anti-toniques, avec la sienne. De même, un joueur préfère de l'information qui est la moins dépendante possible de l'information obtenue par les joueurs pour qui les actions sont soit, substituts stratégiques et isotoniques, soit compléments stratégiques et anti-toniques, avec la sienne. Nous établissons également des conditions suffisantes pour qu'une structure d'information donnée, information publique ou privée par exemple, soit possible à l'équilibre. / This thesis is a collection of three essays in economics of information. Chapter 1 is a general introduction and Chapters 2 to 4 form the core of the thesis. Chapter 2 analyzes information dissemination on the Internet. Online platforms such as Amazon, TripAdvisor or Yelp are now key sources of information for modern consumers. The proportion of consumers consulting online reviews prior to purchasing a good or a service has grown persistently. Yet, sellers have been accused of hiring shills to post fake reviews about their products. This raises the question: Does the presence of shills make reviews less informative? I show that the answers to this question depend on the way the platform presents and summarizes reviews on its website. In particular, I find that withholding information by garbling the reviews benefits information dissemination by inducing the seller to destroy less information with manipulation. Next, I show that the platform's choice regarding how to present reviews hinges on its revenue source. Indeed, a platform that receives sales commissions optimally commits to publishing information differently from a platform that receives revenues from advertisements or from subscription fees. Incidentally, such platforms have contrasting impacts on the amount of information that is transmitted by reviews. Chapter 3 is co-authored with Marc Santugini. In this chapter, we study the impact of third-degree price discrimination in the presence of uninformed buyers who extract noisy information from observing prices. In a noisy learning environment, it is shown that price discrimination can be detrimental to the firm and beneficial to the consumers. On the one hand, discriminatory pricing reduces consumers’ uncertainty, i.e., the variance of posterior beliefs upon observing prices is reduced. Specifically, observing two prices under discriminatory pricing provides more information than one price under uniform pricing even when discriminatory pricing reduces the amount of information contained in each price. On the other hand, it is not always optimal for the firm to use discriminatory pricing since the presence of uninformed buyers provides the firm with the incentive to engage in noisy price signaling. Indeed, if the benefit from price flexibility (through discriminatory pricing) is offset by the cost of signaling quality through two distinct prices, then it is optimal to integrate markets and to use uniform pricing. Finally, Chapter 4 is co-authored with Sidartha Gordon. In this chapter, we study a class of games where players face restrictions on how much information they can obtain on a common payoff relevant state, but have some leeway in covertly choosing the dependence between their signals, before simultaneously choosing actions. Using a new stochastic dependence ordering between signals, we show that each player chooses information that is more dependent on the information of other players whose actions are either isotonic and complements with his actions or antitonic and substitutes with his actions. Similarly, each player chooses information that is less dependent on the information of other players whose actions are antitonic and complements with his actions or isotonic and substitutes with his actions. We then provide sufficient conditions for information structures such as public or private information to arise in equilibrium.
34

Information and control in financial markets

Lee, Samuel January 2009 (has links)
Market Liquidity, Active Investment, and Markets for Information. This paper studies a financial market in which investors choose among investment strategies that exploit information about different fundamentals. On the one hand, the presence of other informed investors generates illiquidity. On the other hand, investors who use different strategies can serve as quasi-noise traders for each other, thereby also supplying each other with liquidity. Thus, investment strategies can be substitutes or complements. Such externalities in information acquisition have effects on investor herding, comovement in prices and liquidity across assets, trade volume, and the informational role of prices. They further affect the relationship between financial markets and information markets. Information market competition fosters investor diversity, whereas monopoly power promotes investor herding. Also, in order to benefit from quasi-noise trading, a financial institution may engage in both proprietary trading and information sales. Security-Voting Structure and Bidder Screening. This paper shows that non-voting shares can promote takeovers. When the bidder has private information, shareholders may refuse to tender because they suspect to sell at an ex-post unfavourable price. The ensuing friction in the sale of cash flow rights can prevent an efficient sale of control. Separating cash flow and voting rights mitigates this externality, thereby facilitating takeovers. In fact, the fraction of non-voting shares can be used to discriminate between efficient and inefficient bidders. The optimal fraction decreases with managerial ability, implying an inverse relationship between firm value and non-voting shares. As non-voting shares increase control contestability, share reunification programs entrench managers of widely held firms, whereas dual-class recapitalizations can increase shareholder wealth. Signaling in Tender Offer Games. This paper examines whether a bidder can use the terms of the tender offer to signal the post-takeover security benefits to the shareholders of a widely held target firm. As atomistic shareholders extract all the gains in security benefits, signaling equilibria are subject to a constraint that is absent from bilateral trade models. The buyer (bidder) must enjoy gains from trade that are excluded from bargaining (private benefits), but can nonetheless be relinquished and enable shareholders to draw inference about the security benefits. Restricted bids and cash-equity offers do not satisfy these requirements. Dilution, debt financing, probabilistic takeover outcomes and toeholds are all viable signals because they make bidder gains depend on the security benefits in a predictable manner. In all the signaling equilibria, lower-valued types must forgo a larger fraction of their private benefits and these signaling costs prevent some takeovers. When the bidder has additional private information about the private benefits as in the case of two-dimensional bidder types, fully revealing equilibria cease to exist. This does not hold once bidders can offer not only cash or equity but also (more) elaborate contingent claims. Offers which include options avoid inefficiencies and implement the symmetric information outcome. Goldrush Dynamics of Private Equity. This paper presents a simple dynamic model of entry and exit in a private equity market with heterogeneous private equity firms, a depletable stock of target companies, and rational learning about investment profitability. The predictions of the model match a number of stylized facts: Aggregate fund activity follows waves with endogenous transitions from boom to bust. Supply and demand in the private equity market are inelastic, and the supply comoves with investment valuations. High industry performance precedes high entry, which in turn precedes low industry performance. There are persistent differences in fund performance across private equity firms, first-time funds underperform the industry, and first-time funds raised in booms are unlikely to be succeeded by a follow-on fund. Fund performance and fund size are positively correlated across firms, but negatively correlated across consecutive funds of a private equity firm. Finally, booms can make ”too much capital chase too few deals.” Reputable Friends as Watchdogs: Social Ties and Governance. To examine how governance is affected when a designated supervisor befriends the person to be supervised, this paper embeds a delegated monitoring problem in a social structure: the supervisor and the agent are friends, and the supervisor desires to be socially recognized for having integrity. Strengthening the friendship weakens the supervisor’s monitoring incentives, forging an alliance against the principal (bonding). But the agent also grows more reluctant to put the supervisor’s perceived integrity at risk, thus becoming more aligned with the principal (bridging). If the supervisor’s desire for social recognition is strong, the principal’s preferences regarding the supervisor-agent friendship are bipolar. Weak friendship makes the supervisor monitor intensively to save face. Strong friendship leads the supervisor to abandon monitoring but the agent to behave well in order to protect the supervisor from losing face. The strength of friendship necessary for the latter outcome decreases in the supervisor’s desire for esteem; that is, image concerns leverage the bridging effect of friendship. This suggests that overlapping personal and professional ties can enhance delegated governance in cultures or contexts where social recognition is important, and provides a novel perspective on issues related to crony capitalism, corporate governance, and organizational culture. / Diss. Stockholm : Handelshögskolan, 2009 Sammanfattning jämte 5 uppsatser

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