Resource Competition on Integral Polymatroids

We study competitive resource allocation problems in which players distribute their demands integrally on a set of resources subject to player-specific submodular capacity constraints. Each player has to pay for each unit of demand a cost that is a nondecreasing and convex function of the total allocation of that resource. This general model of resource allocation generalizes both singleton congestion games with integer-splittable demands and matroid congestion games with player-specific costs. As our main result, we show that in such general resource allocation problems a pure Nash equilibrium is guaranteed to exist by giving a pseudo-polynomial algorithm computing a pure Nash equilibrium.Comment: 17 page

Partial report is the wrong paradigm

Is consciousness independent of the general-purpose information processes known as ‘cognitive access’? The dominantmethodology for supporting this independence hypothesis appeals to partial report experiments as evidence for perceptual consciousness in the absence of cognitive access. Using a standard model of evidential support, and reviewing recent elaborations of the partial report paradigm, this article argues that the paradigm has the wrong structure to support the independence hypothesis. Like reports in general, a subject’s partial report is evidence that she is conscious of information only where that information is cognitively accessed. So partial report experiments could dissociate consciousness from cognitive access only if there were uncontroversial evidence forconsciousness which did not imply reportability. There is no such evidence. An alternative, broadly Marrian methodology for supporting the independence hypothesis is suggested, and some challenges to it outlined. This methodology does not require experimental evidence for consciousness in the absence of cognitive access. Instead it focuses on a function of perceptual consciousness when a stimulus is cognitively accessed. If the processes best suited to implement this function exclude cognitive access, the independence hypothesis will be supported. One relevant function of consciousness may be reflected in reason-based psychological explanations of a subject’s behaviour

The influence of octyl beta-D-glucopyranoside on cell lysis induced by ultrasonic cavitation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98658/1/JAS003482.pd

In Which Content to Specialize? A Game Theoretic Analysis

Part 2: Economics and Technologies for Inter-Carrier ServicesInternational audienceContent providers (CPs) may be faced with the question of how to choose in what content to specialize. We consider several CPs that are faced with a similar problem and study the impact of their decisions on each other using a game theoretic approach. As the number of content providers in a group specializing in a particular content increases, the revenue per content provider in the group decreases. The function that relates the number of CPs in a group to the revenue of each member may vary from one content to another. We show that the problem of selecting the content type is equivalent to a congestion game. This implies that (i) an equilibrium exists within pure policies, (ii) the game has a potential so that any local optimum of the potential function is an equilibrium of the original problem. The game is thus reduced to an optimization problem. (iii) Sequences of optimal responses of players converge to within finitely many steps to an equilibrium. We finally extend this problem to that of user specific costs in which case a potential need not exist any more. Using results from crowding games, we provide conditions for which sequences of best responses still converge to a pure equilibrium within finitely many steps

The sequential price of anarchy for atomic congestion games

In situations without central coordination, the price of anarchy relates the quality of any Nash equilibrium to the quality of a global optimum. Instead of assuming that all players choose their actions simultaneously, here we consider games where players choose their actions sequentially. The sequential price of anarchy, recently introduced by Paes Leme, Syrgkanis, and Tardos then relates the quality of any subgame perfect equilibrium to the quality of a global optimum. The effect of sequential decision making on the quality of equilibria, however, depends on the specific game under consideration.\ud Here we analyze the sequential price of anarchy for atomic congestion games with affine cost functions. We derive several lower and upper bounds, showing that sequential decisions mitigate the worst case outcomes known for the classical price of anarchy. Next to tight bounds on the sequential price of anarchy, a methodological contribution of our work is, among other things, a "factor revealing" integer linear programming approach that we use to solve the case of three players

Aspects of Fractional Superstrings

We investigate some issues relating to recently proposed fractional superstring theories with $D_{\rm critical}<10$. Using the factorization approach of Gepner and Qiu, we systematically rederive the partition functions of the $K=4,\, 8,$ and $16$ theories and examine their spacetime supersymmetry. Generalized GSO projection operators for the $K=4$ model are found. Uniqueness of the twist field, $\phi^{K/4}_{K/4}$, as source of spacetime fermions is demonstrated. Last, we derive a linear (rather than quadratic) relationship between the required conformal anomaly and the conformal dimension of the supercurrent ghost.Comment: 36 pages, CALT-68-1756 Revisions to match form to appear in Comm. Math. Phys. Use standard TeX. Derivation of affine partition functions related to $D=4,6$ models is now shown. References Update

A Process and Outcome Evaluation of a Shelter for Homeless Young Women

To evaluate the processes and outcomes of a short-term shelter, both quantitative and qualitative data were gathered via participant observation, focus group interviews with shelter staff and residents, and individual interviews with a sample of 40 young women who had been homeless prior to using the shelter. The process evaluation showed that the shelter staff strived to utilize an empowerment philosophy in their relationships with residents, but that there were many challenges to implementing this philosophy. The outcome evaluation showed that, at a 3-month follow-up, the participants reported significant improvements in housing, income, independence, and life satisfaction, but most continued to experience poverty and a number of other difficulties. The results were discussed in terms of the implications for future research and the value and limitations of shelters for dealing with homeless youth. The need for more sustained and comprehensive program interventions and supportive social policies was underscored

The asymptotic price of anarchy for k-uniform congestion games

We consider the atomic version of congestion games with affine cost functions, and analyze the quality of worst case Nash equilibria when the strategy spaces of the players are the set of bases of a k-uniform matroid. In this setting, for some parameter k, each player is to choose k out of a finite set of resources, and the cost of a player for choosing a resource depends affine linearly on the number of players choosing the same resource. Earlier work shows that the price of anarchy for this class of games is larger than 1.34 but at most 2.15. We determine a tight bound on the asymptotic price of anarchy equal to ≈1.35188. Here, asymptotic refers to the fact that the bound holds for all instances with sufficiently many players. In particular, the asymptotic price of anarchy is bounded away from 4/3. Our analysis also yields an upper bound on the price of anarchy <1.4131, for all instances