43897550
Forming and searching content-based hierarchical agent clusters in distributed information retrieval systems
The organization and collaborative protocols of agent societies are becoming increasingly important with the growing size of agent networks. Particularly, in a multi-agent-based content-sharing system, a flat, peer-to-peer P2P agent organization is not the most efficient organization for locating relevant agents for queries. This paper not only develops and analyzes a hierarchical agent group formation protocol to build a hybrid organization for large-scale content sharing systems, but proposes a context-aware distributed search algorithm to take advantage of such an organization as well. During the organization formation process, the agents manage their agent-view structures to form a hierarchical topology in an incremental fashion. The algorithm aims to place those agents with similar content in the same group. We evaluate the system performance based on TREC VLC 921 datasets. The results of the experiment demonstrate a significant increase in the cumulative recall ratio CRR measure compared to the flat agent organization and structure.
17695045
A Multi-Agent Approach for Peer-to-Peer Based Information Retrieval System
This paper develops and analyzes distributed search techniques for use in a peer-to-peer (P2P) network-based Information Retrieval (IR) system. In the absence of a centralized mediator with global knowledge that directs requests to appropriate agents, agents must cooperate to forward the queries among themselves so as to find appropriate agents, and return and merge the results in order to fulfill the information retrieval task in a distributed environment. In our approach, the agent society is connected through an agent-view structure maintained by each agent. Initially, the agent-view structures are formed by agents connecting to each other randomly. However, we show that such an approach can be significantly enhanced by dynamically reorganizing the underlying agent-view topology and deploying contextsensitive distributed search algorithms. Experimental results indicate that appropriate organizational structures and distributed search mechanisms can have a positive influence on system performance.
6715931
Evaluating guidelines for empirical software engineering studies
Background. Several researchers have criticized the standards of performing and reporting empirical studies in software engineering. In order to address this problem, Andreas Jedlitschka and Dietmar Pfahl have produced reporting guidelines for controlled experiments in software engineering. They pointed out that their guidelines needed evaluation. We agree that guidelines need to be evaluated before they can be widely adopted. If guidelines are flawed, they will cause more problems that they solve.Aim. The aim of this paper is to present the method we used to evaluate the guidelines and report the results of our evaluation exercise. We suggest our evaluation process may be of more general use if reporting guidelines for other types of empirical study are developed.Method. We used perspective-based inspections to perform a theoretical evaluation of the guidelines. A separate inspection was performed for each perspective. The perspectives used were: Researcher, Practitioner/Consultant, Meta-analyst, Replicator, Reviewer and Author. Apart from the Author perspective, the inspections were based on a set of questions derived by brainstorming. The inspection using the Author perspective reviewed each section of the guidelines sequentially. Results. The question-based perspective inspections detected 42 issues where the guidelines would benefit from amendment or clarification and 8 defects.Conclusions. Reporting guidelines need to specify what information goes into what section and avoid excessive duplication. Software engineering researchers need to be cautious about adopting reporting guidelines that differ from those used by other disciplines. The current guidelines need to be revised and the revised guidelines need to be subjected to further theoretical and empirical validation. Perspective-based inspection is a useful validation method but the practitioner/consultant perspective presents difficulties.
15756415
Assembly Sequence Planning
The sequence of mating operations that can be carried out to assemble a group of parts is constrained by the geometric and mechanical properties of the parts, their assembled configuration, and the stability of the resulting subassemblies. An approach to representation and reasoning about these sequences is described here and leads to several alternative explicit and implicit plan representations. The Pleiades system will provide an interactive software environment for designers to evaluate alternative systems and product designs through their impact on the feasibility and complexity of the resulting assembly sequences.
6097933
The Clar covering polynomial of hexagonal systems III
Abstract The Clar covering polynomial is a recently proposed concept of hexagonal systems by which some important topological indices such as perfect matching count, Clar number, first Herndon number, etc., can be easily obtained. In this paper we establish a relationship between the Clar covering polynomial and sextet polynomial. A lower bound of the Clar number and some properties of coefficients of the Clar covering polynomial are thus deduced. It is mentioned that the summation of coefficients of Clar covering polynomial can be used to calculate the number of perfect matchings of a certain kind of polyominoes relating to crystal physics.
6600637
Localized Content-Based Image Retrieval
We define localized content-based image retrieval as a CBIR task where the user is only interested in a portion of the image, and the rest of the image is irrelevant. In this paper we present a localized CBIR system, ACCIO, that uses labeled images in conjunction with a multiple-instance learning algorithm to first identify the desired object and weight the features accordingly, and then to rank images in the database using a similarity measure that is based upon only the relevant portions of the image. A challenge for localized CBIR is how to represent the image to capture the content. We present and compare two novel image representations, which extend traditional segmentation-based and salient point-based techniques respectively, to capture content in a localized CBIR setting.
17728390
Are Parallel BDI Agents Really Better?
The traditional BDI agent has 3 basic computational components that generate beliefs, generate intentions and execute intentions. They run in a sequential and cyclic manner. This may introduce several problems. Among them, the inability to watch the environment continuously in dynamic environments may be disastrous and makes an agent less rational --the agent may endanger itself. Two possible solutions are by parallelism and by controlling and managing the 3 components in suitable ways. We examine a parallel architecture with three parallel running components which are the belief manager, the intention generator and the intention executor. The agent built with this architecture will have the ability of performing several actions at once. To evaluate the parallel BDI agent, we compare the parallel agent against four versions of sequential agents where the 3 components of the BDI agent are controlled and managed in different ways and different time resources are allocated to them. Experiments are designed to simulate agents based on the sequential and parallel BDI architectures respectively and the ability of the agents to respond to the same sequences of external events of various priorities are assessed. The comparison results show that the parallel BDI agent has quicker response, react to emergencies immediately and its behaviour is more rational.