9590852
Web-based information retrieval support systems: building research tools for scientists in the new information age
The concept of Web-based information retrieval support systems (WIRSS) is introduced. The needs for WIRSS are shown by a detailed case study of existing research article indexing and citation analysis systems, such as current content, DBLP, science citation index and CiteSeer. The objective of WIRSS is to build new and effective research tools for scientists to access, explore and use information on the Web, which may lead to improved research productivity and quality.
6507492
Induction of Classification Rules by Granular Computing
A granular computing model is used for learning classification rules by considering the two basic issues: concept formation and concept relationships identification. A classification rule induction method is proposed. Instead of focusing on the selection of a suitable partition, i.e., a family of granules defined by values of an attribute, in each step, we concentrate on the selection of a single granule. This leads to finding a covering of the universe, which is more general than partition based methods. For the design of granule selection heuristics, several measures on granules are suggested.
449421
Web-based Research Support Systems
Web-based research support systems (WRSS) are a specific type of Web-based support systems (WSS) that support research activities for scientists. They are motivated by the challenges and opportunities of the Web, as well as the needs of scientists. The recent advancements of computer and Web technologies make the implementation of WSS feasible. A general framework of WSS is presented by considering its basic issues. Within the framework, the principles and issues of WRSS are examined. From the conceptual point of view, WRSS may be considered as a new subfield of study. It focuses on a more systematic and coherent treatment of existing isolated studies of research support. From the implementation point of view, WRSS are based on assembling, integration, and adaptation of existing computer technology and information systems for the purpose of research support. The results of WRSS may lead to new and viable research tools.
2932585
A Granular Computing Approach to Machine Learning
The key to granular computing is to make use of granules in problem solving. Classification is one of the well studied problems in machine learning and data mining as it involves of discovery knowledge from large databases. We presents a granular computing view to classification problems and propose a granular computing approach to classification in this paper. The ID3 [8] and PRISM [2] algorithma are studied and extended to granular computing algorithm.
12920787
Deterministic multiuser carrier-frequency offset estimation for interleaved OFDMA uplink
In orthogonal frequency-division multiple access (OFDMA), closely spaced multiple subcarriers are assigned to different users for parallel signal transmission. An interleaved subcarrier-assignment scheme is preferred because it provides maximum frequency diversity and increases the capacity in frequency-selective fading channels. The subcarriers are overlapping, but orthogonal to each other such that there is no intercarrier interference (ICI). Carrier-frequency offsets (CFOs) between the transmitter and the receiver destroy the orthogonality and introduces ICI, resulting in multiple-access interference. This paper exploits the inner structure of the signals for CFO estimation in the uplink of interleaved OFDMA systems. A new uplink signal model is presented, and an estimation algorithm based on the signal structure is proposed for estimating the CFOs of all users using only one OFDMA block. Diversity schemes are also presented to improve the estimation performance. Simulation results illustrate the high accuracy and efficiency of the proposed algorithm.
17927523
An energy-efficient and access latency optimized indexing scheme for wireless data broadcast
Data broadcast is an attractive data dissemination method in mobile environments. To improve energy efficiency, existing air indexing schemes for data broadcast have focused on reducing tuning time only, i.e., the duration that a mobile client stays active in data accesses. On the other hand, existing broadcast scheduling schemes have aimed at reducing access latency through nonflat data broadcast to improve responsiveness only. Not much work has addressed the energy efficiency and responsiveness issues concurrently. This paper proposes an energy-efficient indexing scheme called MHash that optimizes tuning time and access latency in an integrated fashion. MHash reduces tuning time by means of hash-based indexing and enables nonflat data broadcast to reduce access latency. The design of hash function and the optimization of bandwidth allocation are investigated in depth to refine MHash. Experimental results show that, under skewed access distribution, MHash outperforms state-of-the-art air indexing schemes and achieves access latency close to optimal broadcast scheduling
17760529
Tracking a dynamic set of feature points
We address the problems of tracking a set of feature points over a long sequence of monocular images as well as how to include and track new feature points detected in successive frames. Due to the 3-D movement of the camera, different parts of the images exhibit different image motion. Tracking discrete features can therefore be decomposed into several independent and local problems. Accordingly, we propose a localized feature tracking algorithm. The trajectory of each feature point is described by a 2-D kinematic model. Then to track a feature point, an interframe motion estimation scheme is designed to obtain the estimates of interframe motion parameters. Subsequently, using the estimates of motion parameters, corresponding points are identified to subpixel accuracy. Afterwards, the temporal information is processed to facilitate the tracking scheme. Since different feature points are tracked independently, the algorithm is able to handle the image motion arising from general 3-D camera movements. On the other hand, in addition to tracking feature points detected at the beginning, an efficient way to dynamically include new points extracted in subsequent frames is devised so that the information in a sequence is preserved. Experimental results for several image sequences are also reported.
32948109
Electronic image stabilization using multiple visual cues
Image stabilization is a key preprocessing step in dynamic image analysis and deals with the removal of unwanted image motion in a video sequence. This paper presents an integrated algorithm for the problem of image stabilization. The algorithm combines various visual cues such as points and horizon lines, and relies on an extended Kalman filter for the estimation of parameters of interest. We study both calibrated and uncalibrated stabilization cases, and consider the problem of the selection of model dynamics for the estimation of warping parameters. Experimental results from video sequences generated from off-road vehicle platforms show good performance of stabilization algorithm.
2273900
Channel estimation and interference suppression for space-time coded systems in frequency-selective fading channels
Summary It is of great interest to provide high data rate services in wireless communication systems. In order to support such services, it is desirable to extend space-time (ST) coding, originally proposed for known, frequency-nonselective fading channels, to unknown, multipath channels. In this paper, we consider the problem of interference suppression for wireless TDMA (time division multiple access) systems equipped with multiple transmit antennas and receive antennas in frequency-selective fading channels. A novel scheme with space-time block coding based transmit diversity (STTD) is presented to estimate the multipath channel, coherently demodulate information symbols, and meanwhile suppress radio interference. The proposed scheme is simple to implement and able to mitigate interference of various origins, including intersymbol interference (ISI), cochannel interference (CCI), and others. Numerical examples are presented to illustrate the performance of the proposed estimator and detector in multipath Rayleigh-fading channels. Copyright  2002 John Wiley & Sons, Ltd.