Random Surfing Without Teleportation

In the standard Random Surfer Model, the teleportation matrix is necessary to ensure that the final PageRank vector is well-defined. The introduction of this matrix, however, results in serious problems and imposes fundamental limitations to the quality of the ranking vectors. In this work, building on the recently proposed NCDawareRank framework, we exploit the decomposition of the underlying space into blocks, and we derive easy to check necessary and sufficient conditions for random surfing without teleportation.Comment: 13 pages. Published in the Volume: "Algorithms, Probability, Networks and Games, Springer-Verlag, 2015". (The updated version corrects small typos/errors

Managing networks in the public sector: A theoretical study of management strategies in policy networks

Public policy usually develops in complex networks of public, quasi-public and private organizations. It is now generally accepted that these networks set limits to the governance capability of the administration. A good deal less is known about the opportunities which policy networks offer for tackling social and administrative problems. This article deals with the way network management enables government organizations to benefit from networks. Building on the theoretical concepts of 'networks' and 'games', two forms of network management are identified: game management and network structuring. Four key aspects can be identified for both of these management fonns: actors and their relations, resources, rules and perceptions. At thesame time, criteria for the assessment and improvement of network management are examined. The article concludes with a consideration of the limits of network management

Three essays in Financial Networks and Games

Chapter 1: Default and Punishment with Systemic Risk: This essay identifies substituting behaviors in an ex-ante financial system with cyclical default/feedback leading to potential breakdown. Here, firms in a debt network estimate potential default and as such, makes storage decision in order to avoid defaulting. They make these decision due to the potential damages associated with defaults. In doing so, firms optimize their savings strategy given their network/neighborhood effect. We observe properties and existence of a Nash equilibrium under instances where such ex-ante breakdown are caused in part by each owing firm. Equilibrium storage is dominated by the fraction of default not attributed to contagion. We also see a link between firms position in a default network and its storage. As a policy tool, equilibrium under harsh punishment are also socially efficient in achieving minimal default and systemic breakdown. Chapter 2: Frictions in Financial Networks: This essay models transaction cost within an Eisenberg and Noe (2001) clearing system and identifies such clearing properties such as existence, uniqueness and methods of clearing. Further more, it adapts such transaction cost for decision making into the Demange (2016)'s threat index with default feedback and observes the behavior of the index/centrality rankings of each under changing transaction costs. We find under strict conditions, existential possibilities of switching in such rankings for firms involved. Chapter 3: Strategic Interactions in Financial Networks: This essay models interactions of firms in a pre-trading(fixed network of lending/ borrowing) period whereby firms set fixed lending rates given loan management cost. We show strategic substitution in the rate each firm sets and more fundamentally, propose that the rates charged to debtors by a creditor firm is likened to results from a private provision of public good in networks game. We then highlight specific core-periphery network properties in relation to interdependence and Nash rate charged by firms. For welfare policies, we find neutrality of intervention policies that create or reduce transaction cost and improvement based on policies that provide administrative subsidies thus creating an avenue for cost effective resource transfer policy. Lastly, we find significant relationship between a firms centrality measured by weaker negative externality and welfare improvement due to such subsidy

Strongly representable atom structures of relation algebras

Accepted versio

Benchmarking Measures of Network Influence

Identifying key agents for the transmission of diseases (ideas, technology, etc.) across social networks has predominantly relied on measures of centrality on a static base network or a temporally flattened graph of agent interactions. Various measures have been proposed as the best trackers of influence, such as degree centrality, betweenness, and $k$-shell, depending on the structure of the connectivity. We consider SIR and SIS propagation dynamics on a temporally-extruded network of observed interactions and measure the conditional marginal spread as the change in the magnitude of the infection given the removal of each agent at each time: its temporal knockout (TKO) score. We argue that the exhaustive approach of the TKO score makes it an effective benchmark measure for evaluating the accuracy of other, often more practical, measures of influence. We find that none of the common network measures applied to the induced flat graphs are accurate predictors of network propagation influence on the systems studied; however, temporal networks and the TKO measure provide the requisite targets for the hunt for effective predictive measures

Consumption Benefits and Gambling: Evidence From the NCAA Basketball Betting Market

The determinants of the total number of bets placed on games from three on-line sports books are analyzed for the 2008‐9 NCAA basketball season. Betting volume depends on television coverage, temporal factors, the quality of the teams, and the expected closeness of the contest. Our results support the notion that consumption benefits motivate gambling rather than financial gain. Preferences of bettors appear similar to those of sports fans, suggesting that modeling gamblers as wealth‐maximizing investors may not be appropriate, and supports the predictions of the model of gambling developed by Conlisk (1993).gambling; sports betting; bet volume; consumption value

Parallel Weighted Random Sampling

Data structures for efficient sampling from a set of weighted items are an important building block of many applications. However, few parallel solutions are known. We close many of these gaps both for shared-memory and distributed-memory machines. We give efficient, fast, and practicable algorithms for sampling single items, k items with/without replacement, permutations, subsets, and reservoirs. We also give improved sequential algorithms for alias table construction and for sampling with replacement. Experiments on shared-memory parallel machines with up to 158 threads show near linear speedups both for construction and queries