Abstract We outline a preliminary speci cation framework for a prognostic expert system to advise... more Abstract We outline a preliminary speci cation framework for a prognostic expert system to advise General Practitioners and their patients on the individual risks of breast cancer. The system is prognostic in the sense that it considers and presents the likely consequences of alternative monitoring, prophylactic, treatment and lifestyle options available to the patient.
In this paper we describe an analysis of two double auction markets—the clearing house auction an... more In this paper we describe an analysis of two double auction markets—the clearing house auction and the continuous double auction. The complexity of these institutions is such that they defy analysis using traditional game-theoretic techniques, and so we use heuristic-strategy approximation to provide an approximated game-theoretic analysis.
This paper discusses a system of argumentation with a probabilistic semantics and compares it to ... more This paper discusses a system of argumentation with a probabilistic semantics and compares it to two other probabilistic systems|Wellman's qualitative probabilistic networks and Neufeld's probabilistic default reasoning.
Agent-based simulation is increasingly used to analyze the performance of complex systems. In thi... more Agent-based simulation is increasingly used to analyze the performance of complex systems. In this paper we describe results of our work on one specific agent-based model, showing how it can be validated against the equation-based model from which it was derived, and demonstrating the extent to which it can be used to derive additional results over and above those that the equation-based model can provide.
Abstract Agent-based simulation is increasingly used to analyze the performance of complex system... more Abstract Agent-based simulation is increasingly used to analyze the performance of complex systems. There are two main ways agent-based models are built---from equation-based models and directly from data. We are building models in both ways, investigating approaches for creating them and for validating them.
Abstract This paper surveys methods for representing and reasoning with imperfect information. It... more Abstract This paper surveys methods for representing and reasoning with imperfect information. It opens with an attempt to classify the different types of imperfection that may pervade data, and a discussion of the sources of such imperfections. The classification is then used as a framework for considering work that explicitly concerns the representation of imperfect information, and related work on how imperfect information may be used as a basis for reasoning.
In the last few years, increasing numbers of members of the agent community have been adopting te... more In the last few years, increasing numbers of members of the agent community have been adopting techniques from game theory and decision theory. Broadly speaking, decision theory (Raiffa, 1968) is a means of analysing which of a series of options should be taken when it is uncertain exactly what the result of taking the option will be.
Abstract. Firewalls are an important tool in the provision of network security. Packet filtering ... more Abstract. Firewalls are an important tool in the provision of network security. Packet filtering firewalls are configured by providing a set of rules that identify how to handle individual data packets that arrive at the firewall. In large firewall configurations, conflicts may arise between these rules. Argumentation provides a way of handling such conflicts that illuminates their origin, and hence can help a system administrator understand the effects of a given configuration.
Abstract A new algorithm for computing the maximum entropy ranking (me-ranking) over a set of var... more Abstract A new algorithm for computing the maximum entropy ranking (me-ranking) over a set of variable strength defaults is given. Although this requires more information than its predecessor in terms of strengths for defaults, it has a much wider applicability, and allows for greater expressiveness in encoding default knowledge. The algorithm is shown to be sound and complete to the extent that it always produces an me-ranking when one exists. The reasons for multiple rankings and for no ranking are explored.
Abstract—Developing and resourcing coalition plans require an understanding of the policy and res... more Abstract—Developing and resourcing coalition plans require an understanding of the policy and resource availability constraints under which coalition members operate. Policies and resource availability information are not necessarily public knowledge within the coalition. Also, it is difficult to keep track of the policies and resource availabilities of others.
Abstract. This paper presents an argumentation-based approach to deliberation, the process by whi... more Abstract. This paper presents an argumentation-based approach to deliberation, the process by which two or more agents reach a consensus on a course of action. The kind of deliberation that we are interested in is a process that combines both the selection of an overall goal, the reduction of this goal into sub-goals, and the formation of a plan to achieve the overall goal.
We introduce a new application of qualitative models of uncertainty. The qualitative analysis of ... more We introduce a new application of qualitative models of uncertainty. The qualitative analysis of a numerical model of uncertainty reveals the qualitative behaviour of that model when new evidence is obtained. This behaviour can be compared with an expert's specifications to identify those situations in which the model does not behave as expected. We report the result of experiments performed using a probability model, and a model based on the Dempster-Shafer theory of evidence.
Abstract A symbolically quantified logic is presented for reasoning under uncertainty that is bas... more Abstract A symbolically quantified logic is presented for reasoning under uncertainty that is based upon the concept of rough sets. This mathematical model provides a simple yet sound basis for a robust reasoning system. A rule of inference analogous to modus ponens is described, and it is shown how it might be used by a reasoning system to determine the most likely outcome under conditions of uncertain knowledge. An analysis of the robustness of the logic in rule-based reasoning is also presented.<>
Abstract We analyze the competitive advantage of price signal information for traders in simulate... more Abstract We analyze the competitive advantage of price signal information for traders in simulated double auctions. Previous work has established that more information about the price development does not guarantee higher performance. In particular, traders with limited information perform below market average and are outperformed by random traders; only insiders beat the market. However, this result has only been shown in markets with a few traders and a uniform distribution over information levels.
This volume presents the recent developments of the growing area of research taking place at the ... more This volume presents the recent developments of the growing area of research taking place at the interface of argumentation theory and multiagent systems. Argumentation can be abstractly defined as the interaction of different arguments for and against some conclusion. Over the last few years, argumentation has been gaining increasing importance in multiagent systems, mainly as a vehicle for facilitating “rational interaction”(ie, interaction which involves the giving and receiving of reasons).
This paper considers the use of logic-based languages for multiagent negotiation. We begin by mot... more This paper considers the use of logic-based languages for multiagent negotiation. We begin by motivating the use of such languages, and introducing a formal model of logic-based negotiation.
Many autonomous agents operate in domains in which the cooperation of their fellow agents cannot ... more Many autonomous agents operate in domains in which the cooperation of their fellow agents cannot be guaranteed. In such domains negotiation is essential to persuade others of the value of co-operation. This paper describes a general framework for negotiation in which agents exchange proposals backed by arguments which summarise the reasons why the proposals should be accepted. The argumentation is persuasive because the exchanges are able to alter the mental state of the agents involved.
Abstract. Trust is an approach to managing the uncertainty about autonomous entities and the info... more Abstract. Trust is an approach to managing the uncertainty about autonomous entities and the information they store, and so can play an important role in any decentralized system. As a result, trust has been widely studied in multiagent systems and related fields such as the semantic web. Here we introduce a simple approach to reasoning about trust with logic, describe how it can be combined with reasoning about beliefs using logic, and demonstrate its use on an example.
In our previous work on dialogue games for agent interaction, an agent's set of beliefs (Σ) and a... more In our previous work on dialogue games for agent interaction, an agent's set of beliefs (Σ) and an agent's “commitment store”(CS)—the set of locutions uttered by the agent—play a crucial role. The usual assumption made in this work is that the set of beliefs is static through the course of a dialogue, while the commitment store is dynamic. While the assumption of static beliefs is reasonable during the progress of the dialogue, it seems clear that some form of belief change is appropriate once a dialogue is complete.
Abstract. This chapter considers chance discovery and management in a community of intelligent, a... more Abstract. This chapter considers chance discovery and management in a community of intelligent, autonomous, software agents, where agents may have differing beliefs and intentions. For such a community of agents, we derive a set of five requirements for the design of languages and protocols for communications between the agents when discussing chance discovery and management.
Abstract We outline a preliminary speci cation framework for a prognostic expert system to advise... more Abstract We outline a preliminary speci cation framework for a prognostic expert system to advise General Practitioners and their patients on the individual risks of breast cancer. The system is prognostic in the sense that it considers and presents the likely consequences of alternative monitoring, prophylactic, treatment and lifestyle options available to the patient.
In this paper we describe an analysis of two double auction markets—the clearing house auction an... more In this paper we describe an analysis of two double auction markets—the clearing house auction and the continuous double auction. The complexity of these institutions is such that they defy analysis using traditional game-theoretic techniques, and so we use heuristic-strategy approximation to provide an approximated game-theoretic analysis.
This paper discusses a system of argumentation with a probabilistic semantics and compares it to ... more This paper discusses a system of argumentation with a probabilistic semantics and compares it to two other probabilistic systems|Wellman's qualitative probabilistic networks and Neufeld's probabilistic default reasoning.
Agent-based simulation is increasingly used to analyze the performance of complex systems. In thi... more Agent-based simulation is increasingly used to analyze the performance of complex systems. In this paper we describe results of our work on one specific agent-based model, showing how it can be validated against the equation-based model from which it was derived, and demonstrating the extent to which it can be used to derive additional results over and above those that the equation-based model can provide.
Abstract Agent-based simulation is increasingly used to analyze the performance of complex system... more Abstract Agent-based simulation is increasingly used to analyze the performance of complex systems. There are two main ways agent-based models are built---from equation-based models and directly from data. We are building models in both ways, investigating approaches for creating them and for validating them.
Abstract This paper surveys methods for representing and reasoning with imperfect information. It... more Abstract This paper surveys methods for representing and reasoning with imperfect information. It opens with an attempt to classify the different types of imperfection that may pervade data, and a discussion of the sources of such imperfections. The classification is then used as a framework for considering work that explicitly concerns the representation of imperfect information, and related work on how imperfect information may be used as a basis for reasoning.
In the last few years, increasing numbers of members of the agent community have been adopting te... more In the last few years, increasing numbers of members of the agent community have been adopting techniques from game theory and decision theory. Broadly speaking, decision theory (Raiffa, 1968) is a means of analysing which of a series of options should be taken when it is uncertain exactly what the result of taking the option will be.
Abstract. Firewalls are an important tool in the provision of network security. Packet filtering ... more Abstract. Firewalls are an important tool in the provision of network security. Packet filtering firewalls are configured by providing a set of rules that identify how to handle individual data packets that arrive at the firewall. In large firewall configurations, conflicts may arise between these rules. Argumentation provides a way of handling such conflicts that illuminates their origin, and hence can help a system administrator understand the effects of a given configuration.
Abstract A new algorithm for computing the maximum entropy ranking (me-ranking) over a set of var... more Abstract A new algorithm for computing the maximum entropy ranking (me-ranking) over a set of variable strength defaults is given. Although this requires more information than its predecessor in terms of strengths for defaults, it has a much wider applicability, and allows for greater expressiveness in encoding default knowledge. The algorithm is shown to be sound and complete to the extent that it always produces an me-ranking when one exists. The reasons for multiple rankings and for no ranking are explored.
Abstract—Developing and resourcing coalition plans require an understanding of the policy and res... more Abstract—Developing and resourcing coalition plans require an understanding of the policy and resource availability constraints under which coalition members operate. Policies and resource availability information are not necessarily public knowledge within the coalition. Also, it is difficult to keep track of the policies and resource availabilities of others.
Abstract. This paper presents an argumentation-based approach to deliberation, the process by whi... more Abstract. This paper presents an argumentation-based approach to deliberation, the process by which two or more agents reach a consensus on a course of action. The kind of deliberation that we are interested in is a process that combines both the selection of an overall goal, the reduction of this goal into sub-goals, and the formation of a plan to achieve the overall goal.
We introduce a new application of qualitative models of uncertainty. The qualitative analysis of ... more We introduce a new application of qualitative models of uncertainty. The qualitative analysis of a numerical model of uncertainty reveals the qualitative behaviour of that model when new evidence is obtained. This behaviour can be compared with an expert's specifications to identify those situations in which the model does not behave as expected. We report the result of experiments performed using a probability model, and a model based on the Dempster-Shafer theory of evidence.
Abstract A symbolically quantified logic is presented for reasoning under uncertainty that is bas... more Abstract A symbolically quantified logic is presented for reasoning under uncertainty that is based upon the concept of rough sets. This mathematical model provides a simple yet sound basis for a robust reasoning system. A rule of inference analogous to modus ponens is described, and it is shown how it might be used by a reasoning system to determine the most likely outcome under conditions of uncertain knowledge. An analysis of the robustness of the logic in rule-based reasoning is also presented.<>
Abstract We analyze the competitive advantage of price signal information for traders in simulate... more Abstract We analyze the competitive advantage of price signal information for traders in simulated double auctions. Previous work has established that more information about the price development does not guarantee higher performance. In particular, traders with limited information perform below market average and are outperformed by random traders; only insiders beat the market. However, this result has only been shown in markets with a few traders and a uniform distribution over information levels.
This volume presents the recent developments of the growing area of research taking place at the ... more This volume presents the recent developments of the growing area of research taking place at the interface of argumentation theory and multiagent systems. Argumentation can be abstractly defined as the interaction of different arguments for and against some conclusion. Over the last few years, argumentation has been gaining increasing importance in multiagent systems, mainly as a vehicle for facilitating “rational interaction”(ie, interaction which involves the giving and receiving of reasons).
This paper considers the use of logic-based languages for multiagent negotiation. We begin by mot... more This paper considers the use of logic-based languages for multiagent negotiation. We begin by motivating the use of such languages, and introducing a formal model of logic-based negotiation.
Many autonomous agents operate in domains in which the cooperation of their fellow agents cannot ... more Many autonomous agents operate in domains in which the cooperation of their fellow agents cannot be guaranteed. In such domains negotiation is essential to persuade others of the value of co-operation. This paper describes a general framework for negotiation in which agents exchange proposals backed by arguments which summarise the reasons why the proposals should be accepted. The argumentation is persuasive because the exchanges are able to alter the mental state of the agents involved.
Abstract. Trust is an approach to managing the uncertainty about autonomous entities and the info... more Abstract. Trust is an approach to managing the uncertainty about autonomous entities and the information they store, and so can play an important role in any decentralized system. As a result, trust has been widely studied in multiagent systems and related fields such as the semantic web. Here we introduce a simple approach to reasoning about trust with logic, describe how it can be combined with reasoning about beliefs using logic, and demonstrate its use on an example.
In our previous work on dialogue games for agent interaction, an agent's set of beliefs (Σ) and a... more In our previous work on dialogue games for agent interaction, an agent's set of beliefs (Σ) and an agent's “commitment store”(CS)—the set of locutions uttered by the agent—play a crucial role. The usual assumption made in this work is that the set of beliefs is static through the course of a dialogue, while the commitment store is dynamic. While the assumption of static beliefs is reasonable during the progress of the dialogue, it seems clear that some form of belief change is appropriate once a dialogue is complete.
Abstract. This chapter considers chance discovery and management in a community of intelligent, a... more Abstract. This chapter considers chance discovery and management in a community of intelligent, autonomous, software agents, where agents may have differing beliefs and intentions. For such a community of agents, we derive a set of five requirements for the design of languages and protocols for communications between the agents when discussing chance discovery and management.
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Papers by Simon Parsons