Ordered dynamic channel assignment scheme with reassignment inhighway microcells

An ordered dynamic channel assignment with reassignment (ODCAR) scheme is proposed, and its performance is studied in a highway microcellular radio environment. Channels are assigned in an ordered basis in conjunction with a minimax algorithm under cochannel interference constraints, to provide high capacity and to alleviate worst case channel congestion in each microcell. Simulation results show significant performance improvements in terms of channel utilization and probability of call failure, at the expense of an increase in complexity and call switching requirements     

A REVIEW OF PRODUCTION PLANNING AND SCHEDULING MODELS IN THE SEMICONDUCTOR INDUSTRY PART I: SYSTEM CHARACTERISTICS, PERFORMANCE EVALUATION AND PRODUCTION PLANNING

Although the national importance of the semiconductor industry is widely acknowledged, it is only recently that the production planning and scheduling problems encountered in this environment have begun to be addressed using industrial engineering and operations research.techniques. These problems have several features that make them difficult and challenging: random yields and rework, complex product flows, and rapidly changing products and technologies. Hence their solution will contribute considerably to die theory and practice of production planning and control. In a two-part project we present a review of research in this area to date, discuss the applicability of the various approaches and suggest directions for future research. In this paper, Part I, we describe the characteristics of the semiconductor manufacturing environment and review models related to performance evaluation and production planning. Part II will review research on shop-floor control in this industry to date.     

Sociodemographic factors and the variation in syphilis rates among US counties, 1984 through 1993: an ecological analysis

OBJECTIVES: Syphilis in the United States is focally distributed, with high incidence rates in the South and in metropolitan areas nationwide. In this study an ecological analysis, using the county as the unit of analysis, was performed to generate hypotheses about community-level determinants of syphilis rates. METHODS: Bivariate rank correlations and multivariate, backward stepwise elimination linear regressions were performed. Mean annual incidence of primary- and secondary-stage syphilis in a county was the dependent variable, and county sociodemographic characteristics (from census data) were the independent variables. RESULTS: In the multivariate regression model, sociodemographic characteristics accounted for 71% of the variation in syphilis rates among counties. With other factors accounted for, the most highly correlated characteristics were percentage non-Hispanic Black population, county location in the South, percentage of the population that was urban, percentage Hispanic population, and percentage of births to women younger than 20 years. CONCLUSIONS: Most of the variation in syphilis rates among counties is accounted for by sociodemographic characteristics. Identification and remediation of modifiable health determinants for which these factors are markers are needed to improve the health status of these populations.     

Convergence analysis of hybrid bi-directional associative memory neural networks with discrete delays

In this paper, the dynamical characteristics of hybrid bi-directional associative memory (BAM) neural networks with constant transmission delays are investigated. Without assuming the symmetry of synaptic connection weights and the monotonicity and differentiability of activation functions, the Lyapunov functionals are constructed and Halanay-type inequalities are respectively employed to derive the delay-independent sufficient conditions under which the networks converge exponentially to the equilibria associated with temporally uniform external inputs. Some examples are given to illustrate that the results are less conservative and less restrictive than the previously known results.     

Comparison of the glucose-lowering properties of vanadyl sulfate and bis(maltolato)oxovanadium(IV) following acute and chronic administration

The possibility that progesterone or estradiol may regulate expression of G protein in the rat myometrium during the course of pregnancy has been investigated using 1) immunoblot analysis of Gi2 alpha, Gi3 alpha, and Gq alpha subunits and 2) hybridization blot analysis of subunit mRNA. Eighteen hours after administration, estradiol had significantly increased the levels of both Gi2 alpha subunit and Gi2 alpha mRNA (by 40% and 32%, respectively). In control pregnant rats, we observed similar changes at the end of pregnancy, when myometrial concentrations of estradiol had increased, i.e., a 41% increase in immunoreactive Gi2 alpha subunit that correlated with a parallel 45% increase in mRNA levels. In contrast, levels of immunoreactive Gi3 alpha subunit and mRNA, which decreased with advancing gestation, were not influenced by estradiol or progesterone administration. Progesterone administration resulted 30 h later in a significantly decreased level of Gq alpha immunoreactivity (32%) and Gq alpha mRNA (30%). In control rats, Gq alpha protein and mRNA were also significantly lower at midpregnancy under progesterone dominance vs. term. At this stage, a twofold increase in Gq alpha subunit correlated with a 40% increase in mRNA levels. These results demonstrate that myometrial Gi2 alpha and Gq alpha subunits are physiological targets for estradiol and progesterone, respectively, in vivo. Alterations of these G protein levels are discussed in relation to their mediating effects on adenylyl cyclase activity or the phospholipase C pathway during the course of pregnancy.     

A PLL clock generator with 5 to 10 MHz of lock range formicroprocessors

A microprocessor clock generator based on an analog phase-locked loop (PLL) is described for deskewing the internal logic control lock to an external system lock. This PLL is fully generated onto a 1.2-million-transistor microprocessor in 0.8-μm CMOS technology without the need for external components. It operates with a lock range from 5 to 110 MHz. The clock skew is less than 0.1 ns, with a peak-to-peak jitter of less than 0.3 ns for a 50-MHz system clock frequency     

Degradation Behaviors of Metal-Induced Laterally Crystallized n-Type Polycrystalline Silicon Thin-Film Transistors Under DC Bias Stresses

Device degradation behaviors of typical-sized n-type metal-induced laterally crystallized polycrystalline silicon thin-film transistors were investigated in detail under two kinds of dc bias stresses: hot-carrier (HC) stress and self-heating (SH) stress. Under HC stress, device degradation is the consequence of HC induced defect generation locally at the drain side. Under a unified model that postulates, the establishment of a potential barrier at the drain side due to carrier transport near trap states, device degradation behavior such as asymmetric on current recovery and threshold voltage degradation can be understood. Under SH stress, a general degradation in subthreshold characteristic was observed. Device degradation is the consequence of deep state generation along the entire channel. Device degradation behaviors were compared in low V_d-stress and in high V_d-stress condition. Defect generation distribution along the channel appears to be different in two cases. In both cases of SH degradation, asymmetric on current recovery was observed. This observation, when in low V_d-stress condition, is tentatively explained by dehydrogenation (hydrogenation) effect at the drain (source) side during stress     

A transmit/receive IF chip set for WCDMA mobiles in 0.35 /spl mu/m CMOS

An implementation of the IF section of WCDMA mobile transceivers with a set of two chips fabricated in an inexpensive 0.35-/spl mu/m two-poly three-metal CMOS process is presented. The transmit/receive chip set integrates quadrature modulators and demodulators, wide dynamic range automatic gain control (AGC) amplifiers, with linear-in-decibel gain control, and associated circuitry. This paper describes the problems encountered and the solutions envisaged to meet stringent specifications, with process and temperature variations, thus overcoming the limitations of CMOS devices, while operating at frequencies in the range of 100 MHz-1 GHz. Detailed measurement results corroborating successful application of the new techniques are reported. A receive AGC dynamic range of 73 dB with linearity error of less than /spl plusmn/2 dB and spread of less than 5 dB for a temperature range of -30/spl deg/C to +85/spl deg/C in the gain control characteristic has been measured. The modulator measurement shows a carrier suppression of 35 dB and sideband/third harmonic suppression of over 46 dB. The core die area of each chip is 1.5 mm/sup 2/.