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With the advent of cloud computing and the rapid increase in the number of deployed services, the competition between functionally-similar Web services is increasingly governing the markets of services. For example, Amazon and Google are in an intense competition to dominate the market of cloud-based Web services. Such a highly competitive environment motivates and sometimes obliges services to abandon their pure competitive strategies and adopt a cooperative behavior in order to increase their business opportunities and survive in the market. Several approaches have been advanced in the literature to model the cooperation among Web services in a community-based environment. However, the existing approaches suffer from two main drawbacks that limit their effectiveness in the real-world services market. First, they rely on a centralized architecture wherein a master entity is responsible for regulating the community formation process, which creates a single point of failure. Second, they ignore the business potential of the services and treat all of those services in the same way, which demotivates the participation of the well-positioned ones in such communities. To tackle these problems, we distinguish in this paper between two types of services: leaders and followers . Leaders are those services that enjoy high reputation, market share, and capacity of handling requests; whereas followers are those services that cannot compete against the leaders. Thereafter, we model the community formation problem as a virtual trading market between these two types of services and propose a distributed Stackelberg game for this purpose. Promisingly, the proposed model gives guidance to a cooperative model that can be applied in the real markets of Web services in order to achieve higher performance, efficient services compositions, and better resources utilization. The performance of the model is analyzed using a real-life flight booking dataset that includes 2507 services operating on the Web. Simulation results show that the proposed model is able to increase the satisfaction of Web services in terms of gained payoff and reputation and the satisfaction of users in terms of quality of service provided to their requests compared to the existing models, namely the one-stage game theoretical model and a heuristic model. [ABSTRACT FROM AUTHOR]

Highlights: [•] We formalize the question of competing or cooperating for communities of agent-based services. [•] We use the game-theoretic best response technique to analyze competitive/cooperative behaviors of autonomous services within communities. [•] We analyze the computational complexity of the proposed decision mechanism and prove its efficiency. [•] We confirm the theoretical results through extensive simulation using real dataset of services on the web. [ABSTRACT FROM AUTHOR]

Highlights: [•] We define a new set of uncertainty measures for negotiation dialogue games. [•] We analyze the complexity of argumentation selection mechanism. [•] We formalize and analyze the uncertainty index of playing the right move. [•] We formalize and analyze the uncertainty of the move to be accepted by the addressee. [Copyright &y& Elsevier]

Abstract: In agent and (web) service computing, collaboration takes place when distributed entities have limited knowledge and capabilities, so they cannot perform required tasks without interacting and helping each other. For instance, web services, which are loosely-coupled business applications, are called to cooperate in distributed settings for the sake of efficiency. In this context, agents that abstract and act on behalf of web services could act in cooperative groups that gather a number of agents sharing some common goals. Enabling those agent-based web services to decide about their strategies in terms of joining and acting within groups, inviting other agents to join, and leaving a group to act alone is an open issue that we address in this work. In this paper, we propose a framework where agent-based web services select strategies that maximize their outcomes. These strategies could be categorized into cooperative strategies involving other agents and strategies that highlight the single operative attitude. Although cooperation seems to bring better utility to cooperative agents, we highlight that web services in some environments obtain better outcome while they act individually (i.e., outside the group). This means that the cost of cooperation (in some particular cases) might negatively influence the outcome and obtained utility. As solution, we propose in this paper (1) an agent-based model that formalizes web services decision making where different parameters are considered; and (2) a game-theoretic framework that analyzes the web services strategies allowing them to maximize their acting performance where non-zero-sum games are being used. The paper presents theoretical results, which are also confirmed through extensive simulations. [Copyright &y& Elsevier]