In the Hamadryas baboon, males are substantially larger than females. A troop of baboons is subdivided into a number of ‘one-male groups’, consisting of one adult male and one or more females with their young. The male prevents any of ‘his’ females from moving too far from him. Kummer (1971) performed the following experiment. Two males, A and B, previously unknown to each other, were placed in a large enclosure. Male A was free to move about the enclosure, but male B was shut in a small cage, from which he could observe A but not interfere. A female, unknown to both males, was then placed in the enclosure. Within 20 minutes male A had persuaded the female to accept his ownership. Male B was then released into the open enclosure. Instead of challenging male A , B avoided any contact, accepting A’s ownership.

Evolution and the Theory of Games

The Grid 2: Blueprint for a New Computing Infrastructure

Conventional evolutionary game theory predicts that natural selection favours the selfish and strong even though cooperative interactions thrive at all levels of organization in living systems. Recent investigations demonstrated that a limiting factor for the evolution of cooperative interactions is the way in which they are organized, cooperators becoming evolutionarily competitive whenever individuals are constrained to interact with few others along the edges of networks with low average connectivity. Despite this insight, the conundrum of cooperation remains since recent empirical data shows that real networks exhibit typically high average connectivity and associated single-to-broad–scale heterogeneity. Here, a computational model is constructed in which individuals are able to self-organize both their strategy and their social ties throughout evolution, based exclusively on their self-interest. We show that the entangled evolution of individual strategy and network structure constitutes a key mechanism for the sustainability of cooperation in social networks. For a given average connectivity of the population, there is a critical value for the ratio W between the time scales associated with the evolution of strategy and of structure above which cooperators wipe out defectors. Moreover, the emerging social networks exhibit an overall heterogeneity that accounts very well for the diversity of patterns recently found in acquired data on social networks. Finally, heterogeneity is found to become maximal when W reaches its critical value. These results show that simple topological dynamics reflecting the individual capacity for self-organization of social ties can produce realistic networks of high average connectivity with associated single-to-broad–scale heterogeneity. On the other hand, they show that cooperation cannot evolve as a result of “social viscosity” alone in heterogeneous networks with high average connectivity, requiring the additional mechanism of topological co-evolution to ensure the survival of cooperative behaviour.

Cooperation prevails when individuals adjust their social ties

Cloud service selection

The cloud computing paradigm has become a mainstream solution for the deployment of business processes and applications. In the public cloud vision, infrastructure, platform, and software services are provisioned to tenants (i.e., customers and service providers) on a pay-as-you-go basis. Cloud tenants can use cloud resources at lower prices, and higher performance and flexibility, than traditional on-premises resources, without having to care about infrastructure management. Still, cloud tenants remain concerned with the cloud’s level of service and the nonfunctional properties their applications can count on. In the last few years, the research community has been focusing on the nonfunctional aspects of the cloud paradigm, among which cloud security stands out. Several approaches to security have been described and summarized in general surveys on cloud security techniques. The survey in this article focuses on the interface between cloud security and cloud security assurance. First, we provide an overview of the state of the art on cloud security. Then, we introduce the notion of cloud security assurance and analyze its growing impact on cloud security approaches. Finally, we present some recommendations for the development of next-generation cloud security and assurance solutions.

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From Security to Assurance in the Cloud: A Survey

Flexible service selection with user-specific QoS support in service-oriented architecture

Energy-efficient quality of service aware forwarding scheme for Content-Centric Networking

Trust research is a key issue in peer-to-peer (P2P) networks. Reputation-based trust models as one of the good solutions to resolve the trust problems in P2P network are received more and more attention in recent years. One of the fundamental challenges is to capture the evolving nature of a trust relationship between peers and reflect the varied bias or preference of peers in a distributed and open environment. In this paper, we present a fine-grained trust computation model for P2P networks. Our model defines the service as a fined-grained quality-of-service (QoS) (N-dimensional vector), and in order to accurate the recommendation trust computing, several concepts are introduced to reflect the recommenders' current status, history behavior, and the gap between these two behaviors. Also, we firstly introduce the Gauss-bar function to measure the preference similarity between peers. All these will result in a flexible model which represents trust in a manner more close to human intuitions and satisfies the diverse QoS requirements of peers in P2P networks. The extensive simulations have confirmed the efficiency of our model. Copyright © 2009 John Wiley & Sons, Ltd.

FineTrust: a fine-grained trust model for peer-to-peer networks

Trust research has become a key issue in the last few years as a novel and valid solution to ensure the security and application in peer-to-peer (P2P) file-sharing networks. The fundamental challenges lie in what transaction behaviors are most suitable for the measure of reputation and how to resist various threats of manipulation by strategic participants. In this paper, we propose a new trust model based on the technology to calculate the eigenvectors of trust matrices. We define recommended reputation value and recommending reputation value to evaluate the historical transaction behavior for each peer and make them rely on each other tightly. After certain transactions our algorithm makes the entire network from different trust communities, which are corresponding to normal and different types of malicious peers. The reputation values in normal peer community become higher by performing normalization process, thus the behavior of malicious peers will be confined largely. Experiment results confirm the efficiency of our model against the threats of exaggeration, collusion, disguise and single-behavior.

Dual-EigenRep: A Reputation-Based Trust Model for P2P File-Sharing Networks

Current trust structures suffer from a scaling problem, and some may have security problems Even given the topological simplification of bridge Certification Authorities, as cross certificate meshes grow in size and complexity, the number of possible routes between domains increases very quickly, and the time required for path building can increase beyond a tolerable delay for real-time operation This paper proposes a new modified bridge CA (BCA) In certification path process, the new BCA is trivial complexity than original one, but more efficient than unstructured mesh trust model And it also owns some other features Such as more security, less expensive cost based on existing PKI trust model and some etc For improving the performance of certification path process of the new model, we suggest an independent mechanism to automatically discovery and verify these certificate paths among these domains

Mingchu Li

Papers

Flexible service selection with user-specific QoS support in service-oriented architecture

Energy-efficient quality of service aware forwarding scheme for Content-Centric Networking

FineTrust: a fine-grained trust model for peer-to-peer networks

Dual-EigenRep: A Reputation-Based Trust Model for P2P File-Sharing Networks

A New Modified Bridge Certification Authority PKI Trust Model