5927588
Supporting ease-of-use and user control: desired features and structure of Web-based online IR systems
The emergence of Web-based IR systems calls for the need to support ease-of-use as well as user control. This study attempts to investigate users' perceptions of ease-of-use versus user control, and desired functionalities as well as desired interface structure of online IR systems in supporting both ease-of-use and user control. Forty subjects who had an opportunity to learn and use five online databases participated in the study. Multiple methods were employed to collect data. The qualitative and quantitative analysis of the data show that users consider both ease-of-use and user control are essential for effective retrieval. The results are discussed within the context of a model of optimal support for ease-of-use and user control, particularly, emphasizing on the balance between system role and user involvement in achieving various IR sub-tasks.
2773853
State digital library usability: Contributing organizational factors
Usage and user feedback about a state digital library, in which the developers/designers, content providers, different types of libraries and their staffs, and a variety of user groups represent a loose federation of separate organizations with diverse expectations and needs, are investigated. Through corroboratory evidence from usage statistics of Internet-based database services available through the digital library, responses to a statewide-administered library survey, and a Web-based survey of end users, the authors identify contributing factors for the organizational usability of state digital libraries. The authors refine and enhance an organizational usability model for the unique environment of state digital libraries and identify three modes of interaction (influence, communication, activity) and the challenges each interaction presents: in addressing diverse player needs and expectations; the unequal awareness and training in using state digital libraries; and the lack of sufficient communication channels among players. In addition, the findings highlight the double-edged impact of physical libraries on the state digital library.
7985967
Economic Load Dispatch Based on Hybrid Evolutionary Algorithm and Fuzzy Number Ranking Method
In this paper we propose a new economic load dispatch model considered the cost function coefficients with uncertainties and the constraints of ramp rate. The uncertain parameters are represented by fuzzy numbers, with the model called fuzzy dynamic economic load dispatch model (FDELD). A novel hybrid evolutionary algorithm and fuzzy number ranking method is proposed to solve FDELD problem. Hybrid evolutionary algorithm combines evolutionary algorithm of very strong global search ability with quasi-simplex technique of better local search capability. The fuzzy number ranking method is used to compare the fuzzy cost function values when optimizing fuzzy cost function. In addition, this paper gives a novel method dealing with directly constrained conditions, and it is not necessary to construct penalty function, as a common disposal constraints method. The experimental study shows that FDELD is practical and the algorithm and techniques proposed are very efficient to solve FDELD problem.
33783692
BSP Pro: a Java-based BSP performance profiling system
The paper introduces a new parallel performance profiling system for the Bulk Synchronous Parallel (BSP) model. The profiling system, called BSP Pro, consists of a performance profiling tool, BSP Profiler and a performance visualisation tool, BSP Visualiser. The aim of BSP Pro is to assist in the analysis and improvement of BSP program performance by minimising load imbalance among processes. BSP Pro is different from other systems, such as the profiling tools within the Oxford BSP toolset, in terms of both its features and its implementation. It uses BSP Profiler to trace and generate more comprehensive profiling information resulting from BSP program executions. The profiling information is then visualised and shown as performance profiling graphs using BSP Visualiser. The visualising component of BSP Pro is fully developed in Java and utilises Java graphics to expose and highlight process load imbalance in both computation and interprocess communication.
29507323
BSP Performance Analysis and Prediction: Tools and Application
Load balance is one of the critical factors affecting the overall performance of the BSP (Bulk Synchronous Parallel) programs. Without sufficient performance profiling information generated by effective profiling tools, it is often difficult to find out what extent and where load imbalance has occurred in a BSP program. In this paper, we introduce a new parallel performance profiling system for the BSP model. The system traces and generates comprehensive information on timing and communication by each process in each superstep. Its aim is to assist in the improvement of BSP program performance by identifying load imbalance among processors. The profiling data is visualised via a series of performance profiling graphs, making it easier to identify overloaded processes in a superstep. The visualising component of the system is written in Java, thus runs on almost any type of computer systems.
8890829
Blind Source Separation of Temporal Correlated Signals
In this paper, we present a new framework for blind source separation of temporal correlated signals. In general, temporal correlated signals are not independent which means the independence assumption for independent component analysis method is not satisfied. To achieve good separation performance, we apply high order statistics and temporal structure together to put the separation processing in residual level. The residual signals, which is residual part of source signals by extracted temporal structure, are independent. We discuss two types of BSS problem: instantaneous BSS and convolutive BSS. The cost function is derived by simplifying the mutual information of residual signals for both cases. And then we develop efficient learning algorithms respectively. Computer simulations are given to show the separation performance of the proposed algorithm and some comparisons with other algorithms are also provided.
17226014
Analysis of multiple query reformulations on the web: The interactive information retrieval context
This study examines the facets and patterns of multiple Web query reformulations with a focus on reformulation sequences. Based on IR interaction models, it was presumed that query reformulation is the product of the interaction between the user and the IR system. Query reformulation also reflects the interplay between the surface and deeper levels of user interaction. Query logs were collected from a Web search engine through the selection of search sessions in which users submitted six or more unique queries per session. The final data set was composed of 313 search sessions. Three facets of query reformulation (content, format, and resource) as well as nine sub-facets were derived from the data. In addition, analysis of modification sequences identified eight distinct patterns: specified, generalized, parallel, building-block, dynamic, multitasking, recurrent, and format reformulation. Adapting Saracevic's stratified model, the authors develop a model of Web query reformulation based on the results of the study. The implications for Web search engine design are finally discussed and the functions of an interactive reformulation tool are suggested.