A structural approach to matching problems with preferences

This thesis is a study of a number of matching problems that seek to match together pairs or groups of agents subject to the preferences of some or all of the agents. We present a number of new algorithmic results for five specific problem domains. Each of these results is derived with the aid of some structural properties implicitly embedded in the problem. We begin by describing an approximation algorithm for the problem of finding a maximum stable matching for an instance of the stable marriage problem with ties and incomplete lists (MAX-SMTI). Our polynomial time approximation algorithm provides a performance guarantee of 3/2 for the general version of MAX-SMTI, improving upon the previous best approximation algorithm, which gave a performance guarantee of 5/3. Next, we study the sex-equal stable marriage problem (SESM). We show that SESM is W[1]-hard, even if the men's and women's preference lists are both of length at most three. This improves upon the previously known hardness results. We contrast this with an exact, low-order exponential time algorithm. This is the first non-trivial exponential time algorithm known for this problem, or indeed for any hard stable matching problem. Turning our attention to the hospitals / residents problem with couples (HRC), we show that HRC is NP-complete, even if very severe restrictions are placed on the input. By contrast, we give a linear-time algorithm to find a stable matching with couples (or report that none exists) when stability is defined in terms of the classical Gale-Shapley concept. This result represents the most general polynomial time solvable restriction of HRC that we are aware of. We then explore the three dimensional stable matching problem (3DSM), in which we seek to find stable matchings across three sets of agents, rather than two (as in the classical case). We show that under two natural definitions of stability, finding a stable matching for a 3DSM instance is NP-complete. These hardness results resolve some open questions in the literature. Finally, we study the popular matching problem (POP-M) in the context of matching a set of applicants to a set of posts. We provide a characterization of the set of popular matchings for an arbitrary POP-M instance in terms of a new structure called the switching graph exploited to yield efficient algorithms for a range of associated problems, extending and improving upon the previously best-known results for this problem

Intimate Japan

In contemporary Japan, as the Japanese population ages, the low birth rate shrinks the population, and decades of recession radically restructure labor markets' intimate relationships, norms, and ideals are concurrently shifting. This volume explores a broad range of intimate practices in Japan in the first decades of the 2000s to trace how social change is manifests through deeply personal choices. From young people making decisions about birth control to spouses struggling to connect with each other, parents worrying about stigma faced by their adopted children, and queer people creating new terms to express their identifications, Japanese intimacies are commanding a surprising amount of attention, both within and beyond Japan. With ethnographic analysis focused on how intimacy is imagined, enacted, and discussed, the volume offers rich and complex portraits of how people balance personal desires with feasible possibilities and shifting social norms

The making of computer scientists: rendering technical knowledge, gender, and entrepreneurialism in Singapore

This dissertation explores the making of computer scientists in Singapore. I explore how transnational computer science epistemologies and Singaporean state policies work to render the world into technical problems that computer scientists can manipulate and solve. Computer science knowledge and practice is thereby presented as mobile, while masking the colonization of places like Singapore by specifically rendered and gendered American computer science. I also map out the diffractive effects of these transnationally mobile renderings. This research is based on participant observation and interviews centring on an undergraduate computer science program in Singapore. Singaporean and technology media, Singaporean government policies, and university and computer science curricula are also analyzed. I first show how students learn to model and render “reality” into technical frames, creating naturalized computing “worlds,” but ones wherein magic is real and computer scientists are the magicians. Heteronormative binary renderings of gender are (re)produced within these worlds through narratives about algorithms and computing “problems” that constitute a transnational, but US-centric, tradition and that govern the possible ways for students and professors to think about and do computer science. I also show how students themselves are “rendered technical” and their lives and identities “torqued” as they are summoned to inhabit gender norms and hegemonic values of neoliberal competition, passion, and entrepreneurialism. In particular, the performance of passion by certain students works to create a gendered benchmark against which all students come to measure themselves, but which often turns to promoting over-work and exploitation in the name of career development and innovation. Moreover, while some students perform situationally dependent and fluid gender identities, I argue that the predominance of research reducing gender to the question of “women in” computing limits the possibilities both for research on and enactments of gender in computer science and works both to mask and reproduce gender inequalities. Yet, I also show how – in the space produced through conflicting intra-actions of different norms and values – students’ performances of self complicate binary renderings of gender and disrupt the hegemonic status of neoliberal passion and entrepreneurialism, suggesting new possibilities for becoming/being a “good” computer scientist

Essays on intra-household distribution

PhDIn the first chapter of this thesis, I develop a model that combines intrahousehold bargaining with competition on the marriage market - once married, spouses bargain over the allocation of total household income. They have the option of divorce and subsequent remarriage; the value of this outside option is determined endogenously on the marriage market. I use this model to analyse the educational choice. When more women than men obtain a university degree, men without degrees benefit; university educated men, however, are not able to translate this change on the marriage market into a significantly larger share of household income. Hence, men's incentive to invest in education decreases if women's educational attainment increases. Even without assuming any heterogeneity in tastes between men and women, equilibria arise in which men and women decide to become educated at different rates. The second chapter shows empirically, that a woman's propensity to separate from her partner depends positively on male wage inequality on her local marriage market - the more heterogeneous potential future mates are in terms of earnings power, the more likely a woman is to end her relationship. This effect is strongest for couples, where one has a college education but the other one does not. The effect is robust to the inclusion of a variety of controls on the individual level, as well as state and time fixed effects and state specific time trends. The third chapter (co-authored with Julio Robledo) develops a two period family decision making model in which spouse bargain over the allocation of individual time and consumption. If inter-temporally binding contracts are not feasible, household time allocation might be inefficient. We compare two threat point specifications, and show that the threat point specification can influence spouses time allocation, not only the distribution of private consumption

Topology Reconstruction of Dynamical Networks via Constrained Lyapunov Equations

The network structure (or topology) of a dynamical network is often unavailable or uncertain. Hence, we consider the problem of network reconstruction. Network reconstruction aims at inferring the topology of a dynamical network using measurements obtained from the network. In this technical note we define the notion of solvability of the network reconstruction problem. Subsequently, we provide necessary and sufficient conditions under which the network reconstruction problem is solvable. Finally, using constrained Lyapunov equations, we establish novel network reconstruction algorithms, applicable to general dynamical networks. We also provide specialized algorithms for specific network dynamics, such as the well-known consensus and adjacency dynamics.Comment: 8 page

An outline theory of art on cybernetic principles

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The object of this study is to draw art into the common net of organization, along with those other enterprizes more commonly associated with the exercise of intelligence. The method chosen for this is based upon the idea of effective procedures, namely by setting out to construct a (notional) 'art machine'. The argument falls into two parts, the first dealing with the general concept of authorship and the second with its products. Part I offers a definition of an abstract, rudimentary productive process and describes its observers. There is an examination of the relation between structure and purpose, which moves towards a general definition of authorship made in terms of extracting order from a surrounding. Principles of order extraction are examined, with particular reference to the Law of Requisite Variety. Examination of extracted order, as structure, heuristics and the like, leads to discussion of the transmission of purposes between purposeful systems, as well as general problems of constraint, and of regulation and control. Part I ends with a proposal for a paradigm for a rudimentary mechanical author. Part II concentrates on the products of authorship, seeking characterizing features of those that may be classified as art. There is discussion of objective knowledge and its value and of the characteristics of experience as a form of objective knowledge. It is suggested that art is concerned with experience and that this dictates its method, which is to produce simulation procedures based on a language constituted by the synthetic structures discussed in Part I. Lines are suggested for realizing an 'art machine' and there is a review of prospects. A section of notes consisting of speculative ideas and empirical applications connected with the conclusions of the text follows Part II