Statistical timing and power analysis of VLSI considering non-linear dependence

Majority of practical multivariate statistical analysis and optimizations model interdependence among random variables in terms of the linear correlation. Though linear correlation is simple to use and evaluate, in several cases non-linear dependence between random variables may be too strong to ignore. In this paper, we propose polynomial correlation coefficients as simple measure of multi-variable non-linear dependence and show that the need for modeling non-linear dependence strongly depends on the end function that is to be evaluated from the random variables. Then, we calculate the errors in estimation resulting from assuming independence of components generated by linear de-correlation techniques, such as PCA and ICA. The experimental results show that the error predicted by our method is within 1% error compared to the real simulation of statistical timing and leakage analysis. In order to deal with non-linear dependence, we further develop a target-function-driven component analysis algorithm (FCA) to minimize the error caused by ignoring high order dependence. We apply FCA to statistical leakage power analysis and SRAM cell noise margin variation analysis. Experimental results show that the proposed FCA method is more accurate compared to the traditional PCA or ICA.     

1.3 /spl mu/m InGaAsN vertical cavity surface emitting lasers grown by MOCVD

The first InGaAsN VCSELs grown by MOCVD with CW lasing wavelength longer than 1.3 /spl mu/m are reported. The devices were of conventional p-i-n structure with doped DBR mirrors. CW lasing up to 65/spl deg/C was observed, with a maximum output power at room temperature of 0.8 mW for multimode devices and nearly 0.3 mW for single-mode devices.     

A testbed for performance evaluation of load‐balancing strategies for Web server systems

To improve response time of a Web site, one replicates the site on multiple servers. The effectiveness of a replicated server system will depend on how the incoming requests are distributed among replicas. A large number of load‐balancing strategies for Web server systems have been proposed. In this paper we describe a testbed that can be used to evaluate the performance of different load‐balancing strategies. The testbed uses a general architecture which allows different load‐balancing approaches to be supported easily. It emulates a typical World Wide Web scenario and allows variable load generation and performance measurement. We have performed some preliminary experiments to measure the performance of a few policies for load balancing using this testbed. Copyright © 2003 John Wiley & Sons, Ltd.     

Influence of aging temperature,time, and environment on thermo-oxidative behavior of PMR-15: nanomechanical characterization

A series of PMR-15 resin specimens were isothermally aged at 288, 316, and 343 °C over a range of time. For PMR-15 aged at 288 °C, the samples were also subjected to different aging environments including: ambient air, dry air, inert (argon), and pressurized air (0.414 MPa). Nanoindentation was performed to characterize localized mechanical properties as well as the development and growth of the oxidative layer. The measured increase in stiffness in the specimen surface oxidation layer is a manifestation of the chemical changes in the polymer occurring during oxidation. The average elastic modulus in the oxidized region is relatively insensitive to variations in aging temperature, time, and the environments. The thickness of the oxidative layer is observed to increase in the early stages of oxidation and the oxidation process eventually approaches an auto-retardation state. Aging under elevated pressure increases the thickness growth rate of the oxidation layer, while there is no significant difference in growth rate for specimens aged in dry air versus those aged in ambient air. It is shown that the measured average thickness of the oxidation layer and the transition region determined by the nanoindenter is in good agreement with optical microscopy measurements for all conditions considered.     

Interviews as catalysts in a community setting.

Examined the effects of interviews about community experience on subsequent attitudes and behavior of adult residents in 2 new condominium communities. Volunteer (23 households) and randomly selected experimental (17 households) groups of respondents were interviewed in their homes. Questionnaires about community experience were administered shortly after the interviews (at 1 condominium) and 6 mo later (at both), and observers rated the activism of community leaders during the interim. Interviewed respondents gave less socially desirable and more extreme responses to the first questionnaire, reported more involvement in the community, and were rated more active in community affairs than uninterviewed controls (103 households). The dynamics of interviews as catalytic events are considered, and the implications of these findings for future use of interviews are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sleep-disordered breathing in alcoholics: association with age

Sleep apnea and related disorders are not uncommon in abstinent alcoholics. We assessed the relationship between age and the presence and severity of sleep-disordered breathing in alcoholism by performing one night of polysomnography on 75 abstinent alcoholic subjects undergoing treatment for alcoholism. Sleep-disordered breathing (defined as 10 or more apneas plus hypopneas/hr of sleep) was present in 17% of 66 men aged 22-76 and in 0 of 9 women aged 28-63 years. Three percent of men under age 40 years had sleep-disordered breathing compared with 25% of men between ages 40-59 and 75% of those above age 60. Although alcoholics with sleep-disordered breathing had a higher body mass index than those without, the increased frequency over age 40 was statistically significant after controlling for the effects of body mass index. Sleep in subjects with sleep-disordered breathing was significantly more disturbed than in subjects without sleep-disordered breathing. Our findings suggest that sleep-disordered breathing in older male alcoholics is more prevalent than has been reported in most studies of normal men and that the increase in sleep-disordered breathing that occurs with age in alcoholics is greater than the age-related increase in sleep-disordered breathing that occurs in healthy elderly men. Furthermore, sleep-disordered breathing is a significant contributor to sleep disturbance in a substantial proportion of male alcoholics above the age of 40 years.(ABSTRACT TRUNCATED AT 250 WORDS)