20,807 research outputs found
Common Representation of Information Flows for Dynamic Coalitions
We propose a formal foundation for reasoning about access control policies
within a Dynamic Coalition, defining an abstraction over existing access
control models and providing mechanisms for translation of those models into
information-flow domain. The abstracted information-flow domain model, called a
Common Representation, can then be used for defining a way to control the
evolution of Dynamic Coalitions with respect to information flow
Towards a Formal Model of Privacy-Sensitive Dynamic Coalitions
The concept of dynamic coalitions (also virtual organizations) describes the
temporary interconnection of autonomous agents, who share information or
resources in order to achieve a common goal. Through modern technologies these
coalitions may form across company, organization and system borders. Therefor
questions of access control and security are of vital significance for the
architectures supporting these coalitions.
In this paper, we present our first steps to reach a formal framework for
modeling and verifying the design of privacy-sensitive dynamic coalition
infrastructures and their processes. In order to do so we extend existing
dynamic coalition modeling approaches with an access-control-concept, which
manages access to information through policies. Furthermore we regard the
processes underlying these coalitions and present first works in formalizing
these processes. As a result of the present paper we illustrate the usefulness
of the Abstract State Machine (ASM) method for this task. We demonstrate a
formal treatment of privacy-sensitive dynamic coalitions by two example ASMs
which model certain access control situations. A logical consideration of these
ASMs can lead to a better understanding and a verification of the ASMs
according to the aspired specification.Comment: In Proceedings FAVO 2011, arXiv:1204.579
Bargaining Coalitions in the Agricultural Negotiations of the Doha Round: Similarity of Interests or Strategic Choices? An Empirical Assessment
The paper aims at understanding the structural features of the bargaining coalitions in the Doha Round of the WTO. We provide an empirical assessment of the preferences of each negotiating actor looking at general economics indicators, development levels, structure of the agricultural sectors, and trade policies for agricultural products. Bargaining coalitions are analyzed by grouping countries through a cluster analysis procedure. The clusters are compared with existing coalitions, in order to assess their degree of internal homogeneity as well as their common interests. Such a comparison allows the detection of possible “defectors”, i.e. countries that according to their economic conditions and policies seem to be relatively less committed to the positions of the coalition they join.Agricultural trade negotiations, Bargaining coalitions, WTO, Cluster analysis
Reforms and Counter-Reforms in Bolivia
This paper analyzes reforms and counter-reforms in Bolivia in recent decades and their effects on the policymaking process (PMP) and productivity. Bolivia’s PMP has shifted from a formal representative democracy to a “participative and direct type of democracy” where street protest and other non-conventional forms of political participation have become dominant. While reforms have increased productivity, they have failed to secure the political support necessary to assure long-term sustainability. In contrast, counter-reforms have so far enjoyed extensive political support, but productivity has stagnated since this process started, with declining economic growth and job creation—developments likely to undermine support for the counter-reform process. The document stresses the need to rebuild a consensus around a PMP capable of increasing productivity and employment creation while restoring social cohesion.Bolivia, Productivity, Policy Making Process, Reform, Counter-Reform
Reforms and Counter-Reforms in Bolivia
This paper analyzes the process of reforms and counter-reforms witnessed in Bolivia over the last two and a half decades, and the effects these processes have had on productivity. In addition, the paper discusses the changing nature of the policy- making processes underlying the reform and counter-reform processes, in terms of the actors who participated in the PMP, policy domains, and arenas where the PMP was shaped, and the currencies used by different actors in order to press for their demands. Moreover, the paper analyzes the factor underlying the changes which took place in the support given by the population to the reform process.Reforms, Productivity, Political Economy, Bolivia
Complexity of coalition structure generation
We revisit the coalition structure generation problem in which the goal is to
partition the players into exhaustive and disjoint coalitions so as to maximize
the social welfare. One of our key results is a general polynomial-time
algorithm to solve the problem for all coalitional games provided that player
types are known and the number of player types is bounded by a constant. As a
corollary, we obtain a polynomial-time algorithm to compute an optimal
partition for weighted voting games with a constant number of weight values and
for coalitional skill games with a constant number of skills. We also consider
well-studied and well-motivated coalitional games defined compactly on
combinatorial domains. For these games, we characterize the complexity of
computing an optimal coalition structure by presenting polynomial-time
algorithms, approximation algorithms, or NP-hardness and inapproximability
lower bounds.Comment: 17 page
Controlled Matching Game for Resource Allocation and User Association in WLANs
In multi-rate IEEE 802.11 WLANs, the traditional user association based on
the strongest received signal and the well known anomaly of the MAC protocol
can lead to overloaded Access Points (APs), and poor or heterogeneous
performance. Our goal is to propose an alternative game-theoretic approach for
association. We model the joint resource allocation and user association as a
matching game with complementarities and peer effects consisting of selfish
players solely interested in their individual throughputs. Using recent
game-theoretic results we first show that various resource sharing protocols
actually fall in the scope of the set of stability-inducing resource allocation
schemes. The game makes an extensive use of the Nash bargaining and some of its
related properties that allow to control the incentives of the players. We show
that the proposed mechanism can greatly improve the efficiency of 802.11 with
heterogeneous nodes and reduce the negative impact of peer effects such as its
MAC anomaly. The mechanism can be implemented as a virtual connectivity
management layer to achieve efficient APs-user associations without
modification of the MAC layer
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