8107681
A Computational Model of Logic-Based Negotiation
This paper presents a computational model of negotiation based on Nebel's syntax-based belief revision. The model guarantees a unique bargaining solution for each bargaining game without using lotteries. Its game-theoretic properties are discussed against the existence and uniqueness of Nash equilibrium and subgame perfect equilibrium. We also study essential computational properties in relation to our negotiation model. In particular, we show that the deal membership checking is DP-complete and the corresponding agreement inference problem is Π2P-hard.
9693532
Negotiation mechanism for TAC SCM component market
This paper presents a new negotiation mechanism and a new supplier model for Trading Agent Competition Supply Chain Management(TAC SCM). Under the new negotiation mechanism, an agent is allowed to negotiate with component suppliers on price, delivery date and supply quantity while a supplier can autonomously vary its production capacity with market demands and allocate its products to buyers through auction. A mathematical analysis is given to ensure the new negotiation mechanism and supplier model effectively solve the existing problems while keeping most good features of the original TAC SCM game model.
8370711
Consistency of Action Descriptions
As a contribution to the metatheory of reasoning about actions, we present some characteristics of the consistency of action theories. Three levels of consistency are investigated for the evaluation of action descriptions: uniform consistency, consistency of formulas and regional consistency. The first two provide an intuitive resolution of problems of explanation conflicts and fluent dependency. The concept of regional consistency provides for a measure of ramification. A highly expressive form of action descriptions, the normal form, is introduced to facilitate this analysis. The relative satisfiability of the situation calculus is generalized to accommodate non-deterministic effects and ramifications.
1234389
Nonmonotonic Reasoning and Multiple Belief Revision
The aim of the present paper is to reveal the interrelation between general patterns of nonmonotonic reasoning and multiple belief revision. For this purpose we de ne a nonmonotonic inference frame in which individual inference rules have been proposed in the literature but their combination as a system has not been investigated. It is shown that such a system is so strong that almost all the rules (including the supracompactness) suggested for nonmonotonic inference relations in the literature hold in it. We prove that this nonmonotonic inference frame is strictly correspendent with multiple belief revision operation. On the basis of this result we analyse a speci c paradigm of defult theory which satis es all the rules under consideration and discuss limitations of methods based on consequence relations for the study of nonmonotonic reasoning.
35603840
State Minimization Re-visited
A well-known circumscription policy in situation calculus theories of actions is to minimize the Abnormality predicate by varying the Holds predicate. Unfortunately this admitted counter-intuitive models. A different policy of varying the Result function eliminated these models. Explanations of how it did this are not entirely satisfactory, but seem to appeal to informal notions of state minimization. We reexamine this policy and show that there are simple justifications for it that are based on classical automata theory. It incidentally turns out that the description "state minimization" for the varying Result policy is more accurate than the original nomenclature had intended.
15449547
Encoding Solutions of the Frame Problem in Dynamic Logic
We investigate the relationship amongst some solutions to the frame problem. We encode Pednault's syntax-based solution [20], Baker's state-minimization policy [1], and Gelfond & Lifchitz's Action Language A [7] in the propositional dynamic logic (PDL). The formal relationships among these solutions are given. The results of the paper show that dynamic logic, as one of the formalisms for reasoning about dynamic domains, can be used as a formal tool for comparing and unifying logics of action.
5927964
Improving min/max aggregation over spatial objects
We examine the problem of computing MIN/MAX aggregates over a collection of spatial objects. Each spatial object is associated with a weight (value), for example, the average temperature or rainfall over the area covered by the object. Given a query rectangle, the MIN/MAX problem computes the minimum/maximum weight among all objects intersecting the query rectangle. Traditionally such queries have been performed as range search queries. Assuming that the objects are indexed by a spatial access method, the MIN/MAX is computed as objects are retrieved. This requires effort proportional to the number of objects intersecting the query interval, which may be large. A better approach is to maintain aggregate information among the index nodes of the spatial access method; then various index paths can be eliminated during the range search. In this paper we propose four optimizations that further improve the performance of MIN/MAX queries. Our experiments show that the proposed optimizations offer drastic performance improvement over previous approaches. Moreover, as a by-product of this work we present an optimized version of the MSB-tree, an index that has been proposed for the MIN/MAX computation over 1-dimensional interval objects.
3129003
Efficient computation of temporal aggregates with range predicates
A temporal aggregation query is an important but costly operation for applications that maintain time-evolving data (data warehouses, temporal databases, etc.). Due to the large volume of such data, performance improvements for temporal aggregation queries are critical. In this paper we examine techniques to compute temporal aggregates that include key-range predicates (range temporal aggregates). In particular we concentrate on SUM, COUNT and AVG aggregates. This problem is novel; to handle arbitrary key ranges, previous methods would need to keep a separate index for every possible key range. We propose an approach based on a new index structure called the Multiversion SB-Tree, which incorporates features from both the SB-Tree and the Multiversion B-Tree, to handle arbitrary key-range temporal SUM, COUNT and AVG queries. We analyze the performance of our approach and present experimental results that show its efficiency.
206133548
An efficient algorithm to rank Web resources
Abstract How to rank Web resources is critical to Web Resource Discovery (Search Engine). This paper not only points out the weakness of current approaches, but also presents in-depth analysis of the multidimensionality and subjectivity of rank algorithms. From a dynamics viewpoint, this paper abstracts a user's Web surfing action as a Markov model. Based on this model, we propose a new rank algorithm. The result of our rank algorithm, which synthesizes the relevance, authority, integrativity and novelty of each Web resource, can be computed efficiently not by iteration but through solving a group of linear equations.
11522705
A supply chain network equilibrium model with random demands
Abstract In this paper, we develop a supply chain network model consisting of manufacturers and retailers in which the demands associated with the retail outlets are random. We model the optimizing behavior of the various decision-makers, derive the equilibrium conditions, and establish the finite-dimensional variational inequality formulation. We provide qualitative properties of the equilibrium pattern in terms of existence and uniqueness results and also establish conditions under which the proposed computational procedure is guaranteed to converge. Finally, we illustrate the model through several numerical examples for which the equilibrium prices and product shipments are computed. This is the first supply chain network equilibrium model with random demands for which modeling, qualitative analysis, and computational results have been obtained.
377260
Supporting complex queries on multiversion XML documents
Managing multiple versions of XML documents represents a critical requirement for many applications. Recently, there has been much work on supporting complex queries on XML data (e.g., regular path expressions, structural projections, etc.). In this article, we examine the problem of implementing efficiently such complex queries on multiversion XML documents. Our approach relies on a numbering scheme, whereby durable node numbers (DNNs) are used to preserve the order among the nodes of the XML tree while remaining invariant with respect to updates. Using the document's DNNs, we show that many complex queries are reduced to combinations of range version retrieval queries. We thus examine three alternative storage organizations/indexing schemes to efficiently evaluate range version retrieval queries in this environment. A thorough performance analysis is then presented to reveal the advantages of each scheme.