User-friendly dedicated power electronic converter simulator

A user-friendly power electronic simulator for the design and analysis of power electronic circuits is presented. A graphic input interface module called ATOSECG has been developed for the dedicated power electronic converter system simulator ATOSEC5. ATOSECG has tremendously facilitated the interaction of the user with the simulator. Examples of application of the ATOSEC5 simulator for the analysis of a complex multiconverter system are given     

The Web and social networks

The sheer volume of Web data, together with its low signal-to-noise ratio, make it difficult for text-based search engines to locate high-quality pages. Analyzing the links between Web sites has dramatically improved the Web search experience and spawned research into the Web's link structure. This research includes graph-theoretic studies of connectivity, which have shown the Web to have strong similarities with social networks. Self-similarity is pervasive in social networks. While researchers have observed Web self-similarity in other contexts, finding a fractal structure in a graph theoretic setting adds further evidence to the Web's small-world social nature. Thus, researchers seek to explain and exploit the human behavior implicit in the Web's evolving structure. How can we combine the power of Web networks with networks resulting from other human activity? Accomplishing this goal represents knowledge management's key challenge and opportunity.     

Mobility management in integrated wireless-ATM networks

There is an emerging interest in integrating mobile wireless communication with Broadband ISDN based on the ATM technology. Many issues arise when such integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current ATM addresses of mobile terminals and sustaining active ATM connections as mobiles move. The paper presents some architectural options for integrating wireless access to ATM networks and highlights an architecture based oninterworking devices to provide transparent mobility support in existing ATM networks. Location management and handoff solutions for this architecture are then presented. Also, how procedures for multiprotocol transport over ATM networks may be adopted to perform location management is described.A version of this paper appeared in the proceedings of ACM Mobicom '95.     

Synthesizing processed video by filtering temporal relationships

Temporal relationships (motion fields) have been widely exploited by researchers for video processing. Their primary use has been to group pixels in spatiotemporal neighborhoods. Typically, video processing is achieved by filtering, modeling, or analyzing pixels in these neighborhoods. In spite of the widespread use of motion information to process video, rarely are the fields treated as signals, i.e., the temporal relationships are seldom considered as a distinct time series. A notable exception is the generalized autoregressive modeling of these relationships in Rajagopalan et al. (1997). In this work, we present a generalization of finite impulse response filtering applicable to temporal relationships and continue the spirit of that work of treating motion fields as a distinct signal (albeit one that is closely tied to the pixel intensities). Applications presented are preprocessing of video for coding and for noise reduction. Instead of filtering pixels in spatiotemporal neighborhoods directly, we argue that it may be more beneficial to filter the temporal relationships first and then synthesize processed video. Simulations shows MPEG-1 rate gains of up to 20% for coding processed video compared to unprocessed ones where processing leaves the original perceptually unchanged. Noise reduction experiments demonstrate a gain of 0.5 dB at high signal to noise ratios over the best results in the published literature while at low to moderate SNRs, improvements are 0.3 dB lower.     

Advances in discrete material handling system design

The paper presents an outline of the research done in the area of facility layout and discrete material handling system design. The objective of this paper is to observe the trend in the literature in the area of manufacturing system design and predict the direction of future research in this area. The paper attempts to link the areas of facility layout design and material flow network design. A methodology for solving the integrated design problem is presented. An algorithm which aids in solving the combined pick-up/drop-off point location and material handling flowpath problem is outlined.     

Selective hydrogenation of olefinic bonds in styrene-isoprene-styrene triblock copolymer by palladium acetate catalyst

Homogeneous catalytic hydrogenation of styrene-isoprene-styrene triblock copolymer (SIS) has been carried out selectively at the carbon-carbon double bond in the presence of palladium acetate catalyst under mild conditions. Degree of hydrogenation has been calculated with the help of infrared and nuclear magnetic resonance spectroscopic techniques. Almost 90 mol % complete hydrogenation has been achieved at 60°C under 1.4 MPa hydrogen pressure, 40 mg catalyst (for 2 g of polymer) in chloroform-acetone solution for 1 h. © 1993 John Wiley & Sons, Inc.     

Right ventricular blood flow during left ventricular support in an experimental porcine model

BACKGROUND: Right ventricular blood flow may be adversely affected during left ventricular assist device (LVAD) use leading to right ventricular (RV) ischemia and RV dysfunction. This study characterized normal RV blood flow responses to LVAD operation. METHODS: Seven Yorkshire pigs weighing 74.4 +/- 3.4 kg underwent right coronary artery blood flow measurements with an ultrasonic flow probe and injection of radiolabeled microspheres. A Thoratec LVAD was used in either synchronous or asynchronous modes and RV loading was increased using a pulmonary artery snare. RESULTS: The RV blood flow was compared between three regions that differed in proximity to the right coronary artery: proximal segment, mid-RV, and distal. The right ventricular distal flow was 0.93 +/- 0.07 mL x min-1 x g-1 compared with 0.74 +/- 0.06 mL x min-1 x g-1 at right ventricular proximal flow during control measurements (p = 0.0001). This difference was maintained during LVAD operation in either synchronous or asynchronous modes and also during pulmonary artery constriction. CONCLUSIONS: Global RV flow is not adversely affected by LVAD use. A flow gradient occurs along the right coronary artery with the distal vascular bed having relatively less reserve, which may be more susceptible to ischemia in patients with preexisting coronary disease or RV distention during LVAD use.     

Multi-agent based collaborative fault detection and identification in chemical processes

Fault detection and identification (FDI) has received significant attention in literature. Popular methods for FDI include principal component analysis, neural-networks, and signal processing methods. However, each of these methods inherit certain strengths and shortcomings. A method that works well under one circumstance might not work well under another when different features of the underlying process come to the fore. In this paper, we show that a collaborative FDI approach that combines the strengths of various heterogeneous FDI methods is able to maximize diagnostic performance. A multi-agent framework is proposed to realize such collaboration in practice where different FDI methods, i.e: principal component analysis, self-organizing maps, non-parametric approaches, or neural-networks are combined. Since the results produced by different FDI agents might be in conflict, we use decision fusion methods to combine FDI results. Two different methods – voting-based fusion and Bayesian probability fusion are studied here. Most monitoring and fault diagnosis algorithms are computationally complex, but their results are often needed in real-time. One advantage of the multi-agent framework is that it provides an efficient means for speeding up the execution time of the various FDI methods through seamless deployment in a large-scale grid. The proposed multi-agent approach is illustrated through fault diagnosis of the startup of a lab-scale distillation unit and the Tennessee Eastman Challenge problem. Extensive testing of the proposed method shows that combining diagnostic classifiers of different types can significantly improve diagnostic performance.