Characterization and design methodology for low-distortion MOSFET-C analog structures in multithreshold deep-submicrometer SOI CMOS technologies

The harmonic distortion (HD) of MOSFETs operating in the triode regime is thoroughly investigated for the different device types of a multi-V/sub th/ deep-submicrometer 0.12-/spl mu/m silicon-on-insulator (SOI) CMOS process. The measurements performed in a wide temperature range (25/spl deg/C-220/spl deg/C) and on devices with different oxide thicknesses and channel dopings help to identify the relative impact of the different physical mechanisms at the origin of HD. A measurement-based and design-oriented methodology is finally developed to compare device types, biases and configurations responding to practical design targets.     

Deterioration of visual information in face classification using Eigenfaces and Fisherfaces

In the area of biometrics, face classification becomes one of the most appealing and commonly used approaches for personal identification. There has been an ongoing quest for designing systems that exhibit high classification rates and portray significant robustness. This feature becomes of paramount relevance when dealing with noisy and uncertain images. The design of face recognition classifiers capable of operating in presence of deteriorated (noise affected) face images requires a careful quantification of deterioration of the existing approaches vis-à-vis anticipated form and levels of image distortion. The objective of this experimental study is to reveal some general relationships characterizing the performance of two commonly used face classifiers (that is Eigenfaces and Fisherfaces) in presence of deteriorated visual information. The findings obtained in our study are crucial to identify at which levels of noise the face classifiers can still be considered valid. Prior knowledge helps us develop adequate face recognition systems. We investigate several typical models of image distortion such as Gaussian noise, salt and pepper, and blurring effect and demonstrate their impact on the performance of the two main types of the classifiers. Several distance models derived from the Minkowski family of distances are investigated with respect to the produced classification rates. The experimental environment concerns a well-known standard in this area of face biometrics such as the FERET database. The study reports on the performance of the classifiers, which is based on a comprehensive suite of experiments and delivers several design hints supporting further developments of face classifiers. Gabriel Jarillo Alvarado obtained his B.Sc. degree in Biomedical Engineering from the Universidad Iberoamericana, Mexico. In 2003 he obtained his M.Sc. degree from the University of Alberta at the Department of Electrical and Computer Engineering, he is currently enrolled in the Ph.D. program at the same University. His research interests involve machine learning, pattern recognition, and evolutionary computation with particular interest to biometrics for personal identification. Witold Pedrycz is a Professor and Canada Research Chair (CRC) in Computational Intelligence) in the Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada. His research interests involve Computational Intelligence, fuzzy modeling, knowledge discovery and data mining, fuzzy control including fuzzy controllers, pattern recognition, knowledge-based neural networks, relational computing, and Software Engineering. He has published numerous papers in this area. He is also an author of 9 research monographs. Witold Pedrycz has been a member of numerous program committees of conferences in the area of fuzzy sets and neurocomputing. He currently serves on editorial board of numereous journals including IEEE Transactions on Systems Man and Cybernetics, Pattern Recognition Letters, IEEE Transactions on Fuzzy Systems, Fuzzy Sets & Systems, and IEEE Transactions on Neural Networks. He is an Editor-in-Chief of Information Sciences. Marek Reformat received his M.Sc. degree from Technical University of Poznan, Poland, and his Ph.D. from University of Manitoba, Canada. His interests were related to simulation and modeling in time-domain, as well as evolutionary computing and its application to optimization problems For three years he worked for the Manitoba HVDC Research Centre, Canada, where he was a member of a simulation software development team. Currently, Marek Reformat is with the Department of Electrical and Computer Engineering at University of Alberta. His research interests lay in the areas of application of Computational Intelligence techniques, such as neuro-fuzzy systems and evolutionary computing, as well as probabilistic and evidence theories to intelligent data analysis leading to translating data into knowledge. He applies these methods to conduct research in the areas of Software and Knowledge Engineering. He has been a member of program committees of several conferences related to Computational Intelligence and evolutionary computing. Keun-Chang Kwak received B.Sc., M.Sc., and Ph.D. degrees in the Department of Electrical Engineering from Chungbuk National University, Cheongju, South Korea, in 1996, 1998, and 2002, respectively. During 2002–2003, he worked as a researcher in the Brain Korea 21 Project Group, Chungbuk National University. His research interests include biometrics, computational intelligence, pattern recognition, and intelligent control.     

CO2 saturation, distribution and seismic response in two-dimensional permeability model

Carbon dioxide capture and storage (CCS) has been actively researched as a strategy to mitigate CO(2) emissions into the atmosphere. The three components in CCS are monitoring, verification, and accounting (MVA). Seismic monitoring technologies can meet the requirements of MVA, but they require a quantitative relationships between multiphase saturation distributions and wave propagation elastic properties. One of the main obstacles for quantitative MVA activities arises from the nature of the saturation distribution, typically classified anywhere from homogeneous to patchy. The emerging saturation distribution, in turn, regulates the relationship between compressional velocity and saturation. In this work, we carry out multiphase flow simulations in a 2-D aquifer model with a log-normal absolute permeability distribution and a capillary pressure function parametrized by permeability. The heterogeneity level is tuned by assigning the value of the Dykstra-Parson (DP) coefficient, which sets the variance of the log-normal horizontal permeability distribution in the entire domain. Vertical permeability is a 10th of the horizontal value in each gridcell. We show that despite apparent differences in saturation distribution among different realizations, CO(2) trapping and the V(p)-S(w) Rock Physics relationship are mostly functions of the DP coefficient. When the results are compared with the well accepted limits, Gassmann-Wood (homogeneous) (A Text Book of Sound; G. Bell and Suns LTD: London, 1941) and Gassmann-Hill (patchy) models, the V(p)-S(w) relationship never reaches the upper bound, that is, patchy model curve, even at the highest heterogeneity level in the model.     

Optimum design of the reconfiguration system for a 6-degree-of-freedom parallel manipulator via motion/force transmission analysis

Journal of Mechanical Science and Technology - This research introduces a 6-degree-of-freedom parallel manipulator with a reconfigurable fixed base; the manipulator performance has been evaluated...     

The stability of power system markets

Market equilibrium conditions can be derived from more general dynamic equations describing the marketplace. Dynamic equations provide insights into the behavior and stability of markets which are not available from static models. For example, markets with a single supplier with declining linear costs (economies of scale) may or may not be stable, depending on specific cost characteristics. Markets with more than one supplier with declining linear costs are always unstable. This paper illustrates a situation where the removal of congestion makes a market unstable     

Night Irrigation Reduction for Water Saving in Medium-Sized Systems

In many medium-sized irrigation systems water is wasted during the night because demand is low and supply is not reduced accordingly. A hydrodynamic model was applied, using MIKE 11 as a software tool, to simulate abrupt discharge changes and their travel times along small irrigation canals. Filling and emptying of the canal were also analyzed. The model was calibrated with data of a field experiment that included startup, positive, and negative surges. A technique was developed to take into account the considerable water losses in the canal. Performance indicators efficiency, adequacy, equity, and dependability, proposed by Molden and Gates in 1990, were redefined using the concept of usefully delivered discharge. The newly defined indicators were consequently used to find the gate operation scenario that meets optimally the target day and night discharges. It was found that it is feasible to implement night delivery reduction. The calibrated model was used to develop guidelines for the operation of the canal with daily flow variation, resulting in considerable water savings during the night.     

Infection and associated risk factors in the immediate postoperative period of pediatric liver transplantation: a study of 176 transplants

BACKGROUND AND OBJECTIVE: To assess the outcomes of vitreoretinal surgery in the treatment of vision-threatening posterior segment complications of X-linked retinoschisis. PATIENTS AND METHODS: The authors performed a retrospective analysis of 16 eyes from 11 patients who underwent vitreoretinal surgery. All the patients had a documented positive family history of X-linked retinoschisis, and all patients had bilateral macular disease. RESULTS: The ages of the patients ranged from 14 months to 37 years (mean age 15.1 years; median age 11.5 years), and postoperative follow-up ranged from 3 months to 10 years (mean 2.8 years; median 1 year). The indications for surgical intervention included rhegmatogenous retinal detachment (12 eyes), vitreous hemorrhage (2 eyes), progression of the schisis cavity through the fovea (2 eyes), cataract associated with a persistent hyperplastic primary vitreous-like condition (2 eyes), and exudative maculopathy (1 eye). The primary surgical intervention included pars plana vitrectomy alone (7 eyes), pars plana vitrectomy and pars plana lensectomy (4 eyes), and a scleral buckle procedure alone (5 eyes). Surgical success (defined as reattachment of the retina, removal of media opacities, or arrest of schisis progression) was achieved in 14 of 16 eyes, after an average of 1.2 procedures per eye. The major reason for reoperations was recurrent retinal detachment due to proliferative vitreoretinopathy. Two eyes were eventually enucleated due to pain associated with neovascular glaucoma resulting from recurrent retinal detachment. Of the remaining 14 eyes, visual acuity improved in 8 eyes and remained unchanged in 6 eyes. CONCLUSION: Vitreoretinal surgery is often helpful in stabilizing or improving visual function in patients with posterior segment complications from X-linked retinoschisis.     

Characteristics of glaucoma drainage implants during dynamic and steady-state flow conditions

OBJECTIVE: This study aimed to ascertain whether the Optimed, Krupin, and Ahmed drainage devices function as valves that vary resistance depending on flow conditions to maintain pressure within a desired range. STUDY DESIGN: Experimental study. INTERVENTION: The three devices and a control cannula were submerged in fluid and perfused with balanced salt solution using a computer-driven apparatus that continuously monitors flow (Q) and pressure (P). In one set of experiments, the flow rates were maintained at 2, 5, 10, 25, or 50 microliters/min until steady-state pressures were achieved. In another set of experiments, the flow rate was increased linearly from 0 to 100 microliters/min over 15 to 20 minutes. MAIN OUTCOME MEASURES: The resistance of each implant was calculated from the first set of experiments by dividing the change in pressure (P) by the change in flow (Q) between successive perfusion rates. Flow-pressure curves were plotted from the experiments in which perfusion rate was increased linearly. RESULTS: Resistance remained relatively constant for the cannula (0.18-0.24 mmHg/microliter/min), the Krupin (0.09-0.25 mmHg/microliter/min), and the Optimed implants (0.04-0.08) throughout the tested flow rates. For the Ahmed device, conversely, resistance decreased proportionally (2.86-0.05 mmHg/microliter/min) to the increase in flow. When flow rate was increased linearly from 0 to 100 microliters/min, the Optimed and Krupin devices as well as the cannula generated a linear pressure response with a constant slope. The pressure in the two devices increased at a rate of 0.11 mmHg/microliter compared to 0.23 mmHg/microliter/min for the cannula. The flow-pressure curve for the Ahmed implant was distinct with a steep initial pressure rise and an essentially constant pressure of 12 mmHg thereafter. CONCLUSION: The Optimed and Krupin devices displayed resistance and pressure responses to various flow conditions that were similar to those of a cannula or flow resistor. In these devices, resistance remained relatively stable and pressure increased linearly with flow. The Ahmed device, conversely, functioned as a valve that closely regulated pressure within a desired range by decreasing or increasing resistance as a function of flow.     

Heart disease education and prevention program targeting immigrant Latinos: using focus group responses to develop effective interventions

Although research has provided considerable knowledge concerning the positive effects of behavioral change on morbidity and mortality from heart disease and related risk factors, some segments of the population have not benefited equitably from this information. In April 1995, the National Heart, Lung, and Blood Institute (NHLBI) conducted seven focus groups to determine knowledge and attitudes about heart disease and associated risk factors, identify media usage and preferences, and assess publications usage and preferences among Spanish-speaking Latino immigrants residing in the Washington, D.C., metropolitan area. This information was gathered to assist in the development of key messages and strategies for the NHLBI Latino Community Cardiovascular Disease Prevention and Outreach Initiative, Salud para su Corazón--a heart disease prevention and education campaign. Findings from these focus groups indicate that Latinos may not benefit from heart disease prevention messages developed for the general population because of language and cultural differences. The researchers concluded that health education and disease prevention programs targeting the Latino community should develop educational materials and interventions that address language preferences and cultural values. Furthermore, to be effective, these programs should show people how to make positive behavioral changes based on their current circumstances, while remaining sensitive to the fact that Latino immigrants face major life adjustments and many are still greatly influenced by their country of origin.