Motivated by the problem of automatically composing network accessible services, such as those on the World Wide Web, this paper proposes an approach to building agent technology based on the notion of generic procedures and customizing user constraint. We argue that an augmented version of the logic programming language Golog provides a natural formalism for automatically composing services on the Semantic Web. To this end, we adapt and extend the Golog language to enable programs that are generic, customizable and usable in the context of the Web. Further, we propose logical criteria for these generic procedures that define when they are knowledge self-sufficient and physically selfsufficient. To support information gathering combined with search, we propose a middle-ground Golog interpreter that operates under an assumption of reasonable persistence of certain information. These contributions are realized in our augmentation of a ConGolog interpreter that combines online execution of information-providing Web services with offline simulation of worldaltering Web services, to determine a sequence of Web Services for subsequent execution. Our implemented system is currently interacting with services on the Web. 1

Web services-- Web-accessible programs and devices – are a key application area for the Semantic Web. With the proliferation of Web services and the evolution towards the Semantic Web comes the opportunity to automate various Web services tasks. Our objective is to enable markup and automated reasoning technology to describe, simulate, compose, test, and verify compositions of Web services. We take as our starting point the DAML-S DAML+OIL ontology for describing the capabilities of Web services. We define the semantics for a relevant subset of DAML-S in terms of a first-order logical language. With the semantics in hand, we encode our service descriptions in a Petri Net formalism and provide decision procedures for Web service simulation, verification and composition. We also provide an analysis of the complexity of these tasks under different restrictions to the DAML-S composite services we can describe. Finally, we present an implementation of our analysis techniques. This implementation takes as input a DAML-S description of a Web service, automatically generates a Petri Net and performs the desired analysis. Such a tool has broad applicability both as a back end to existing manual Web service composition tools, and as a stand-alone tool for Web service developers.

Like classical planning, the execution of high-level agent programs requires a reasoner to look all the way to a final goal state before even a single action can be taken in the world. This deferral is a serious problem in practice for large programs. Furthermore, the problem is compounded in the presence of sensing actions which provide necessary information, but only after they are executed in the world. To deal with this, we propose (characterize formally in the situation calculus, and implement in Prolog) a new incremental way of interpreting such high-level programs and a new high-level language construct, which together, and without loss of generality, allow much more control to be exercised over when actions can be executed. We argue that such a scheme is the only practical way to deal with large agent programs containing both nondeterminism and sensing.

An important concept for intelligent agent systems is goals. Goals have two aspects: declarative (a description of the state sought), and procedural (a set of plans for achieving the goal). A declarative view of goals is necessary in order to reason about important properties of goals, while a procedural view of goals is necessary to ensure that goals can be achieved efficiently in dynamic environments. In this paper we propose a framework for goals which integrates both views. We discuss the requisite properties of goals and the link between the declarative and procedural aspects, then derive a formal semantics which has these properties. We present a high-level plan notation with goals and give its formal semantics.

For many realistic applications, a cognitive agent should have both reactive and deliberative behavior [1]. The first type of behavior concerns the recognition of emergency situations in time and provides rapid responses whereas the second type of behavior concerns the planning of actions to achieve its long-term goals. In order to implement an agent's deliberative behavior, its mental attitudes such as goals and beliefs as well as the interaction between these attitudes should be implemented. Issues related to the implementation of the agents ' mental attitudes can be considered as object-level concerns while issues related to the implementation of agent deliberation and the interaction between mental attitudes form meta-level concerns [2]. Agent deliberation is not limited to the planning of the tasks, but it includes various types of decisions at each moment of time [3] such as how to select a goal from a set of possible goals and whether revising a plan or executing it. These types of decisions, which constitute the agent's

Motivated by the problem of automatically composing network accessible services, such as those on the World Wide Web, this paper proposes an approach to building agent technology based on the the notion of generic procedures and customizing user constraint. We argue that an augmented version of the logic programming language Golog provides a natural formalism for programming Web services. To this end, we adapt and extend the Golog language to enable programs that are generic, customizable and usable in the context of the Web. We realize these extensions in an augmented ConGolog interpreter that combines online execution of information-providing Web services with offline simulation of world-altering Web services, to determine a sequence of Web Services for subsequent execution. Our implemented system is currently interacting with services on the Web. 1

Abstract. Work on agent communication languages has since long striven to achieve adequate speech act semantics; partly, the problem is that references to an agent’s architecture (in particular a BDI-like architecture) would be required in giving such semantics more rigorously. On the other hand, BDI agent-oriented programming languages have had their semantics formalised for an abstract versions only, neglecting “practical” aspects such as communication primitives; this means that, at least in what concerns communication, implementations of BDI programming languages have been ad hoc. This paper tackles, however preliminarily, both these problems by giving semantics to speech-act based messages received by an AgentSpeak(L) agent. AgentSpeak(L) is a BDI, agentoriented, logic programming language that has received a great deal of attention in recent years. The work in this paper builds upon a structural operational semantics to AgentSpeak(L) that we have given in previous work. The contribution of this paper is two-fold: we here extend our earlier work on providing a solid theoretical background on which to base existing implementations of AgentSpeak(L) interpreters, as well as we shed light on a more computationally grounded approach to giving semantics for (the core) illocutionary forces used in speech-act based agent communication languages. 1

In this paper we address the problem of planning with complex actions. We are motivated by the problem of automated Web service composition, in which planning must be performed using predefined complex actions or services as the building blocks of a plan. Planning with complex actions is also compelling in primitive action planning domains because it enables the exploitation of reusable subplans, potentially improving the efficiency of planning. This paper provides a formal, semantically-justified account of how to plan with complex actions using operator-based planning techniques. A key contribution of this work is the definition, characterization, and computation of preconditions and conditional effects for complex actions. While we use the situation calculus and Golog to formalize the task and our solution, the results in this paper are directly applicable to most action theories and planning systems.

The paper discusses a top-down approach to model soccer knowledge, as it can be found in soccer theory books. The goal is to model soccer strategies and tactics in a way that they are usable for multiple RoboCup soccer leagues, i.e. for different hardware platforms. We investigate if and how soccer theory can be formalized such that specification and execution is possible. The advantage is clear: theory abstracts from hardware and from specific situations in leagues.

in this paper, we develop an account of the kind of deliberation that an agent that is doing planning or executing high-level programs under incomplete information must be able to perform.