My thesis contains essays on voting theory, market structures and fiscal federalism: (i) One Person, Many Votes: Divided Majority and Information Aggregation, (ii) Runoff Elections and the Condorcet Loser, (iii) On the Influence of Rankings when Product Quality Depends on Buyer Characteristics, and (iv) Redistributing Income under Fiscal Vertical Imbalance.<p><p>(i) One Person, Many Votes: Divided Majority and Information Aggregation (joint with Micael Castanheira)<p>In elections, majority divisions pave the way to focal manipulations and coordination failures, which can lead to the victory of the wrong candidate. This paper shows how this flaw can be addressed if voter preferences over candidates are sensitive to information. We consider two potential sources of divisions: majority voters may have similar preferences but opposite information about the candidates, or opposite preferences. We show that when information is the source of majority divisions, Approval Voting features a unique equilibrium with full information and coordination equivalence. That is, it produces the same outcome as if both information and coordination problems could be resolved. Other electoral systems, such as Plurality and Two-Round elections, do not satisfy this equivalence. The second source of division is opposite preferences. Whenever the fraction of voters with such preferences is not too large, Approval Voting still satisfies full information and coordination equivalence.<p><p>(ii) Runoff Elections and the Condorcet Loser<p>A crucial component of Runoff electoral systems is the threshold fraction of votes above which a candidate wins outright in the first round. I analyze the influence of this threshold on the voting equilibria in three-candidate Runoff elections. I demonstrate the existence of an Ortega Effect which may unduly favor dominated candidates and thus lead to the election of the Condorcet Loser in equilibrium. The reason is that, contrarily to commonly held beliefs, lowering the threshold for first-round victory may actually induce voters to express their preferences excessively. I also extend Duverger's Law to Runoff elections with any threshold below, equal or above 50%. Therefore, Runoff elections are plagued with inferior equilibria that induce either too high or too low expression of preferences.<p><p>(iii) On the Influence of Rankings when Product Quality Depends on Buyer Characteristics<p>Information on product quality is crucial for buyers to make sound choices. For "experience products", this information is not available at the time of the purchase: it is only acquired through consumption. For much experience products, there exist institutions that provide buyers with information about quality. It is commonly believed that such institutions help consumers to make better choices and are thus welfare improving.<p>The quality of various experience products depends on the characteristics of buyers. For instance, conversely to the quality of cars, business school quality depends on buyers (i.e. students) characteristics. Indeed, one of the main inputs of a business school is enrolled students. The choice of buyers for such products has then some features of a coordination problem: ceteris paribus, a buyer prefers to buy a product consumed by buyers with "good" characteristics. This coordination dimension leads to inefficiencies when buyers coordinate on products of lower "intrinsic" quality. When the quality of products depends on buyer characteristics, information about product quality can reinforce such a coordination problem. Indeed, even though information of high quality need not mean high intrinsic quality, rational buyers pay attention to this information because they prefer high quality products, no matter the reason of the high quality. Information about product quality may then induce buyers to coordinate on products of low intrinsic quality.<p>In this paper, I show that, for experience products which quality depends on the characteristics of buyers, more information is not necessarily better. More precisely, I prove that more information about product quality may lead to a Pareto deterioration, i.e. all buyers may be worse off due.<p><p>(iv) Redistributing Income under Fiscal Vertical Imbalance (joint with Marjorie Gassner and Vincenzo Verardi)<p>From the literature on decentralization, it appears that the fiscal vertical imbalance (i.e. the dependence of subnational governments on national government revenues to support their expenditures) is somehow inherent to multi-level governments. Using a stylized model we show that this leads to a reduction of the extent of redistributive fiscal policies if the maximal size of government has been reached. To test for this empirically, we use some high quality data from the LIS dataset on individual incomes. The results are highly significant and point in the direction of our theoretical predictions.<p> / Doctorat en Sciences économiques et de gestion / info:eu-repo/semantics/nonPublished

In many real world situations, especially involving multiagent systems and artificial intelligence, participating agents often need to agree upon a common alternative even if they have differing preferences over the available alternatives. Voting is one of the tools of choice in these situations. Common and classic applications of voting in modern applications include collaborative filtering and recommender systems, metasearch engines, coordination and planning among multiple automated agents etc. Agents in these applications usually have computational power at their disposal. This makes the study of computational aspects of voting crucial. This thesis is devoted to a study of computational complexity of several fundamental algorithmic and complexity-theoretic problems arising in the context of voting theory. The typical setting for our work is an “election”; an election consists of a set of voters or agents, a set of alternatives, and a voting rule. The vote of any agent can be thought of as a ranking (more precisely, a complete order) of the set of alternatives. A voting profile comprises a collection of votes of all the agents. Finally, a voting rule is a mapping that takes as input a voting profile and outputs an alternative, which is called the “winner” or “outcome” of the election. Our contributions in this thesis can be categorized into three parts and are described below. Part I: Preference Elicitation. In the first part of the thesis, we study the problem of eliciting the preferences of a set of voters by asking a small number of comparison queries (such as who a voter prefers between two given alternatives) for various interesting domains of preferences. We commence with considering the domain of single peaked preferences on trees in Chapter 3. This domain is a significant generalization of the classical well studied domain of single peaked preferences. The domain of single peaked preferences and its generalizations are hugely popular among political and social scientists. We show tight dependencies between query complexity of preference elicitation and various parameters of the single peaked tree, for example, number of leaves, diameter, path width, maximum degree of a node etc. We next consider preference elicitation for the domain of single crossing preference profiles in Chapter 4. This domain has also been studied extensively by political scientists, social choice theorists, and computer scientists. We establish that the query complexity of preference elicitation in this domain crucially depends on how the votes are accessed and on whether or not any single crossing ordering is a priori known. Part II: Winner Determination. In the second part of the thesis, we undertake a study of the computational complexity of several important problems related to determining winner of an election. We begin with a study of the following problem: Given an election, predict the winners of the election under some fixed voting rule by sampling as few votes as possible. We establish optimal or almost optimal bounds on the number of votes that one needs to sample for many commonly used voting rules when the margin of victory is at least n (n is the number of voters and is a parameter). We next study efficient sampling based algorithms for estimating the margin of victory of a given election for many common voting rules. The margin of victory of an election is a useful measure that captures the robustness of an election outcome. The above two works are presented in Chapter 5. In Chapter 6, we design an optimal algorithm for determining the plurality winner of an election when the votes are arriving one-by-one in a streaming fashion. This resolves an intriguing question on finding heavy hitters in a stream of items, that has remained open for more than 35 years in the data stream literature. We also provide near optimal algorithms for determining the winner of a stream of votes for other popular voting rules, for example, veto, Borda, maximin etc. Voters’ preferences are often partial orders instead of complete orders. This is known as the incomplete information setting in computational social choice theory. In an incomplete information setting, an extension of the winner determination problem which has been studied extensively is the problem of determining possible winners. We study the kernelization complexity (under the complexity-theoretic framework of parameterized complexity) of the possible winner problem in Chapter 7. We show that there do not exist kernels of size that is polynomial in the number of alternatives for this problem for commonly used voting rules under a plausible complexity theoretic assumption. However, we also show that the problem of coalitional manipulation which is an important special case of the possible winner problem admits a kernel whose size is polynomial bounded in the number of alternatives for common voting rules. \Part III: Election Control. In the final part of the thesis, we study the computational complexity of various interesting aspects of strategic behaviour in voting. First, we consider the impact of partial information in the context of strategic manipulation in Chapter 8. We show that lack of complete information makes the computational problem of manipulation intractable for many commonly used voting rules. In Chapter 9, we initiate the study of the computational problem of detecting possible instances of election manipulation. We show that detecting manipulation may be computationally easy under certain scenarios even when manipulation is intractable. The computational problem of bribery is an extensively studied problem in computational social choice theory. We study computational complexity of bribery when the briber is “frugal” in nature. We show for many common voting rules that the bribery problem remains intractable even when the briber’s behaviour is restricted to be frugal, thereby strengthening the intractability results from the literature. This forms the subject of Chapter 10.

published_or_final_version / Law / Master / Master of Laws

by Lee Lap-fung, Francis. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 187-197). / Abstracts in English and Chinese; questionnaire in Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- The background of the 1998 election --- p.10 / Chapter Chapter 3 --- Approaches to election and media effects studies --- p.20 / Chapter Chapter 4 --- Activating informed participation - a conceptual model for empirical evaluation --- p.33 / Chapter Chapter 5 --- Design and methods --- p.47 / Chapter Chapter 6 --- "News consumption, knowledge and sophistication" --- p.51 / Chapter Chapter 7 --- Media and political attitudes --- p.65 / Chapter Chapter 8 --- Voter turnout --- p.100 / Chapter Chapter 9 --- The pitfalls of media strategic coverage: How media fall short from activating informed participation --- p.120 / Chapter Chapter 10 --- Conclusion: Mass media and political participation in Hong Kong --- p.147 / Appendix A Variable constructions and statistical procedures --- p.159 / Appendix B Questionnaires and basic information about the data --- p.165 / "Appendix C Electoral system,vote calculating method, and candidate lists" --- p.180 / Reference --- p.187

Many e-voting techniques have been proposed but not widely used in reality. One of the problems associated with most of existing e-voting techniques is the lack of transparency, leading to a failure to deliver voter assurance. In this work, we propose a transparent, auditable, end-to-end verifiable, and mutual restraining e-voting protocol that exploits the existing multi-party political dynamics such as in the US. The new e-voting protocol consists of three original technical contributions -- universal verifiable voting vector, forward and backward mutual lock voting, and in-process check and enforcement -- that, along with a public real time bulletin board, resolves the apparent conflicts in voting such as anonymity vs. accountability and privacy vs. verifiability. Especially, the trust is split equally among tallying authorities who have conflicting interests and will technically restrain each other. The voting and tallying processes are transparent to voters and any third party, which allow any voter to verify that his vote is indeed counted and also allow any third party to audit the tally. For the environment requiring receipt-freeness and coercion-resistance, we introduce additional approaches to counter vote-selling and voter-coercion issues. Our interactive voting protocol is suitable for small number of voters like boardroom voting where interaction between voters is encouraged and self-tallying is necessary; while our non-interactive protocol is for the scenario of large number of voters where interaction is prohibitively expensive. Equipped with a hierarchical voting structure, our protocols can enable open and fair elections at any scale.

Tsang Chun Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves [98-103]). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abbreviations --- p.ii / List of tables and figures --- p.iii / Chapter Chapter One --- Introduction --- p.1 / Plan of the Dissertation --- p.3 / Chapter Chapter Two --- Demonstrating The Electoral Decline --- p.5 / The Changing Hong Kong Electorate --- p.5 / The Electoral Decline of DP --- p.10 / Aggregate vs. Individual Changes --- p.14 / The DP Voters --- p.19 / Chapter Chapter Three --- Explaining The Electoral Decline: Hints From Literature --- p.29 / Electoral Change in Western Democracies --- p.29 / Factors of Voting Behavior --- p.35 / Voting Behavior Studies in Hong Kong --- p.41 / Chapter Chapter Four --- Explaining The Electoral Decline: A Speculation --- p.48 / Societal Changes in Hong Kong --- p.49 / Political Attitudes --- p.54 / Hypothesis --- p.64 / Chapter Chapter Five --- Explaining The Electoral Decline: Testing The Hypothesis --- p.65 / Measurement of Variables --- p.65 / Findings: Bivariate Analysis --- p.71 / Findings: Multivariate Analysis --- p.75 / Chapter Chapter Six --- Conclusion --- p.83 / The Electoral Decline of DP: The Story in Summary --- p.83 / Limitations --- p.87 / At the End --- p.93 / Bibliography --- p.98

Es existiert eine Vielzahl an Web 2.0-Applikationen, welche es einer Gruppe von Personen ermöglichen, einen gemeinsamen Termin zu finden (z. B. doodle.com, moreganize.ch, whenisgood.net, agreeadate.com, meetomatic.com, etc.) Der Ablauf ist simpel: Ein Initiator legt eine Terminumfrage an und schickt den Link zu der Umfrage zu den potentiellen Teilnehmern. Nachdem jeder Teilnehmer der Anwendung seine Verfügbarkeiten mitgeteilt hat, kann anhand dieser Informationen ein Termin gefunden werden, der am besten passt. Maßnahmen um die Vertraulichkeit und Integrität der Daten zu schützen finden in allen bestehenden Applikationen zu wenig Beachtung. In dieser Dissertation wurde eine Web 2.0-Applikation entwickelt, welche es zulässt Terminabstimmungen zwischen mehreren Teilnehmern durchzuführen und dabei möglichst wenige Vertrauensannahmen über alle Beteiligten zu treffen. / Applications which help users to schedule events are becoming more and more important. A drawback of most existing applications is, that the preferences of all participants are revealed to the others. We propose a schemes, which are able to schedule events in a privacy-enhanced way. In addition, Dudle, a Web 2.0 application is presented which implements these schemes.

This master's thesis describes design, implementation and testing of online voting system. Based on the research of existing solutions, as well as the identification of their shortcomings for the target user group, the requirements for the new system are specified. This information system is primarily intended to be used for assembly of unit owners, members meeting of building housing cooperative, or meeting of the municipal council, general meeting of shareholders and similar.

No description available.

This study examines the current situation regarding e-voting in four selected European countries as well as whether Sweden can implement e-voting and achieve success. With the help of a literature study, the study defines the advantages and disadvantages of e-voting and the traditional voting procedure and through a case study, the current situation is identified by the selected European countries and an interview is conducted to gain an insight into the Swedish voting procedure and where Sweden stands when it comes to e-voting. By analyzing the interview and doing a comparative analysis of the key factors that affected the failure or success of e-voting in the selected countries with the key factors identified in Sweden, the result will be clear whether an implementation in Sweden can be successful or not. / Denna studie undersöker den nuvarande situationen gällande e-röstning i fyra valda europeiska länder samt om Sverige kan implementera e-röstning och nå framgång. Med hjälp av en litteraturstudie definierar studien för- och nackdelarna med e-röstning samt det traditionella röstningsförfarandet och genom en fallstudie identifieras den nuvarande situationen av dom valda europeiska länderna samt att en intervju utförs för att få en inblick av det svenska röstningsförfarandet samt vart Sverige står när det gäller e-röstning. Genom att analysera intervjun och göra en jämförelseanalys av nyckelfaktorerna som påverkat misslyckandet eller framgången av e-röstning i dom valda länderna med dom nyckelfaktorerna som identifierats i Sverige kommer resultatet vara tydligt om en implementering i Sverige hade nått framgång eller inte.