Catálogo de publicaciones - libros

Multi-agent systems involve agents interacting with each other and the environment and working to achieve individual and group goals. The achievement of group goals requires that agents work together within teams. In this paper we first introduce three philosophical approaches that result from different answers to two key questions. Secondly we consider three theoretical frameworks for modelling team behaviour. Next we look at two agent implementation models. Finally, we consider one of those implementation models — JACK Teams — and place it in the context of the philosophical debate and the theoretical frameworks.

Agent coordination is the ability to manage the interdependencies of activities between agents while agent cooperation is the process used for an agent to voluntarily enter a relationship with another to achieve a system derived goal. We describe and show the concepts of Coordinative Cooperation and Cooperative Coordination using examples. These concepts demonstrate the ability for intelligent agents to distinguish between cooperation from coordination and vice-versa. Both concepts can be integrated into a process, using a cognitive cycle to explain the interaction between coordination and cooperation. Furthermore, this paper will discuss how the coordination/cooperation loop is initialised and can be affected by Coordinative and Cooperative events. We recommend suggestions on how these concepts can be designed and implemented in a multiagent system (MAS) and introduce AC^3M, which is a prototype of this cognitive loop.

Topological theory of intelligent agent networks provides crucial information about the structure of agent distribution over a network. Agent network topologies not only take agent distribution into consideration but also consider agent mobility and intelligence in a network. Current research in the agent network topology area adopts topological theory from the distributed system and computing network fields without considering mobility and intelligence aspects. Moreover, current agent network topology theory is not systematic and relies on graph-based methodology, which is inefficient in describing large-scale agent networks. In this paper, we systematically classify the agent network topologies and propose a new description language called Topological Description Language for Agent networks (TDLA), which incorporates the mobility and intelligence characteristics in an agent network.

Intelligent agents are powerful tools for complex and dynamic problems. Belief Desire Intension (BDI) is one of the most popular agent architectures for reactive goal directed agents. Planning is intrinsic for intelligent behaviour. But planning from first principle is costly in terms of computation time and resources. BDI agents retain their reactive property by avoiding planning from real-time planning by using predefined plan library designed by agent designers. BDI agents look for a plan in the library to achieve their goals. If the agent could find a plan it fails to achieve the goal. It would be useful to have some real-time look ahead planning capability within BDI framework. In this paper we have proposed an architecture that includes (re) planning in BDI agents. The proposed architecture describes how to integrate a real-time planner with replanning capability in the current BDI architecture. Replanning capability is important for reactive behaviour.

The past five years have witnessed an explosion of interest in the use of cooperation logics for reasoning about multi-agent systems. Since the development of ATL, there are many multi-agent cooperation logics developed as an extension to ATL. The cooperation logic called the Normative Alternating-time Temporal Epistemic Logic (NATEL ) is developed to extend ATL. Four key contributions have been made. Firstly, the strong and unrealistic assumption of the other two extended cooperation logics of ATL (ATEL, NATL*) that different agents are not allowed to control the same actions have been done away with. Secondly, functions that involved actions are given in more detail, so that the relations between actions and knowledge, actions and agents, actions and states can be researched in depth and separately. Thirdly, actions, knowledge and normative ability can be represented in the object language other than only in the underlying semantics. Lastly, since actions, knowledge and normative ability are taken into account at the same time, the expressive power and flexibility of NATEL are much richer than the other two extended cooperation logics of ATL.

Quantum computing is an important field of research that applies concepts of quantum physics to building more efficient computers. Although only rudimentary quantum computers have been built so far, many researchers believe that quantum computing has great potential and the quantum computers can efficiently perform some tasks which are otherwise not feasible on a classical computer, The Hamiltonian cycle problem is to determine whether a given graph has a Hamiltonian cycle or not. This problem belongs to the class of NP-complete problems, widely believed to intractable or hard on classical computers. Design of faster-than-classical quantum algorithms for important algorithmic problems has been an interesting intellectual adventure and achievement all along and their existence keeps being one of the key stimuli to those trying to overcome enormous technology problems to build (powerful) quantum computers. In this paper, we have used undirected graphs with varied number of vertices and we have shown how to determine the existence of a Hamiltonian cycle in a given graph. We have also illustrated how quantum search can be applied to obtain the solution of the Hamiltonian cycle problem much faster than the classical approach.

In this paper, we introduce a real-time temporal knowledge logic, called RTKL , which is a combination of real-time temporal logic and knowledge logic. It is showed that temporal modalities such as “always in an interval”, “until in an interval”, and knowledge modalities such as “knowledge in an interval” and “common knowledge in an interval” can be expressed in such a logic. The model checking algorithm is given. Furthermore, we add cooperation modalities to RTKL and get a new logic RATKL , which can express not only real-time temporal and epistemic properties but also cooperation properties. The model checking algorithm for RATKL is also given.

By applying the probability estimation of the unavailable attributes derived from the available attributes to the neighborhood system, the suited degree of each neighbor to a given object is depicted. Therefore, the neighborhood space with guaranteed suited precision is obtained. We show how to shrink the rule search space via VPRS model for this space, and also, we will prove the incredibility degree of decision class is guaranteed by the two-layer thresholds.

Service description usually presumes a representation of the world model. The Description Logic (DL) is an efficient way for representing the world model, esp. on Semantic Web, because of its framework, decidable reasoning, and popularity. DL can bring structure to services, but only DL itself is inadequate for modelling dynamic aspect of Web services. In this paper, Dynamic Description Logic (DDL) is proposed to combine DLs with action formalisms. The interaction between actions and the DL-based world model is embodied in two aspects. On one hand, DL knowledge base provides knowledge and information for the reasoning on actions; on the other hand, the information stored in DL knowledge base is changed by the execution of actions. In DDL, two basic reasoning tasks are defined to check precondition and effects of actions. Based on the relationship between DDL and a transition system, a reasoning support for DDL is also given by translating actions into logic programs. By the combination of DLs and actions, DDL brings a better view of how services impact the world, facilitates interoperation between services, and enables the reuse of already available algorithms and engines for service reasoning. Thus, it can provide a logical way for embracing actions into Semantic Web.

An ontology consists of concepts and the subsumption relation between these concepts, and is assumed to be a tree under the subsumption relation. In the process of building and maintaining ontologies, new statements which may contradict with exiting statements are added to the ontologies constantly. The ontology revision is necessary to accommodate new statements. In terms of the method of the axiomatization, one axiom system for the ontology revision, called the Z axiom system, is given, which is proved to satisfy the principles of the success, consistency and minimal change. Unlike the belief revision which is monotonic, the ontology revision may not be monotonic, and not only extracts some statements contradictory with a revising statement, extracts statements which are not contradictory with the revising statement, but also adds new statements to keep the tree structure of the revised ontology and satisfy the minimal change. One concrete ontology revision operator is proposed, which is proved to satisfy the Z axiom system.