6317532
Multi-agent based peer-to-peer information retrieval systems with concurrent search sessions
In cooperative peer-to-peer information retrieval systems, each node can be considered an intelligent agent and these agents work collectively to provide an information retrieval service. In order to effectively support multiple and concurrent search sessions in the network, we propose two traffic engineering techniques that minimize processing and communication bottlenecks. One is a novel agent control mechanism whose elements include resource selection, local search scheduling, and feedback-based load control. The other is a new two-phase query routing algorithm based on organizational knowledge. Experimental results show that this framework can reduce congestion situations, increase system throughput, and improve considerably the overall system utility.
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.
16834995
An LDA-based Community Structure Discovery Approach for Large-Scale Social Networks
Community discovery has drawn significant research interests among researchers from many disciplines for its increasing application in multiple, disparate areas, including computer science, biology, social science and so on. This paper describes an LDA(latent Dirichlet Allocation)-based hierarchical Bayesian algorithm, namely SSN-LDA (simple social network LDA). In SSN-LDA, communities are modeled as latent variables in the graphical model and defined as distributions over the social actor space. The advantage of SSN-LDA is that it only requires topological information as input. This model is evaluated on two research collaborative networkst: CtteSeer and NanoSCI. The experimental results demonstrate that this approach is promising for discovering community structures in large-scale networks.
39496103
An Application of Well-orderly Trees in Graph Drawing
Well-orderly tree is a powerful technique capable of deriving new results in graph encoding, graph enumeration and graph generation [3, 5]. In this paper, by using well-orderly trees, we prove that any plane graph G with n vertices has a visibility representation with height , which can be constructed in linear time. This improves the best previous bound of .
5415099
Face Annotation for Family Photo Album Management
In this paper, we propose a framework to semi-automatically annotate faces in family photo albums. The core of the framework is the features used to define face similarity and this results in the learning algorithm used to refine automatic face annotation. We have adopted similarity based search and relevance feedback ideas developed for content-based image retrieval and a set of simple yet effective color and texture based features, in addition to the traditional face recognition features, in performing candidate annotation search. The experimental evaluation of the proposed approach has been conducted with a family album of 1707 photos and the results show that the proposed approach is an effective and efficient one for semi-automatic family photo album annotation.
16979558
Region-based relevance feedback in image retrieval
Relevance feedback and region-based representation of images are two effective ways to improve accuracy in content-based image retrieval. We propose a novel relevance feedback approach based on region representation. It can be considered as a special case of the query point movement method in region-based image retrieval. By assembling all the segmented regions of positive examples together and resizing the regions to emphasize the latest positive examples, we form a composite image as the optimal query. A region-based image similarity measure is used to calculate the distance between the optimal query and an image in the database. An incremental clustering technique is also considered to improve the retrieval efficiency. Experimental results show that the proposed approach is effective in improving the performance of content-based image retrieval systems.
1857778
Boosting image orientation detection with indoor vs. outdoor classification
Automatic detection of image orientation is a very important operation in photo image management. In this paper, we propose an automated method based on the boosting algorithm to estimate image orientations. The proposed method has the capability of rejecting images based on the confidence score of the orientation detection. Also, images are classified into indoor and outdoor, and this classification result is used to further refine the orientation detection. To select features more sensitive to the rotation, we combine the features by subtraction operation and select the most useful features by boosting algorithm. The proposed method has several advantages: small model size, fast classification speed, and effective rejection scheme.
32668520
2D DGT induced fluxes in sediments and soils (2D DIFS)
Diffusive gradients in thin films (DGT) is an emerging, dynamic, measuring technique that can provide diverse information on the concentrations and behaviour of solutes, including chemical speciation and partitioning between solid phase and solution in waters, sediments and soils. The DGT device, which accumulates solute in a binding layer after transport through a well-defined diffusion layer, is simple to construct and use. However, complete interpretation of the dependence of mass accumulation with time requires a numerical model of the transport and reactions occurring within the device and its deployment medium. We have developed a software tool that models the temporal dependence of DGT induced fluxes from soils or sediments by considering diffusion of solutes in two dimensions (2D) and incorporating first order exchange of solute between solid phase and solution. Microniches of elevated concentrations, that emulate zones of high microbial activity, can be created in the soil or sediment. The solver uses an advanced 2D FEM method and a flexible and user-friendly Graphical User Interface, which incorporates essential model calibration tools, is provided. This solution in 2D is shown to substantially increase the accuracy of the simulation, compared to that achieved with the established DIFS software that provides only a 1D solution, and yet it still has short calculation times on modern PCs. The 2D model is shown to provide a good approximation to the full 3D solution, obtained using FEMLAB, when the supply from the solid phase is larger than supply by diffusion. Example simulations are provided for the three major solute supply situations, namely diffusion only, very rapid and sustained supply from the solid phase and two intermediate cases of partial resupply.