Influence of pressure dependence of the yield criterion on the strain-rate-intensity factor

The strain-rate-intensity factor is the coefficient of the principal singular term in an expansion of the equivalent strain rate in a series in the vicinity of maximum-friction surfaces. Its value controls the physical processes in a thin material layer near the frictional interfaces. The objective of the present paper is to study the effects of the pressure dependence of the yield criterion on the strain-rate-intensity factor. The results can be used to develop new methods for predicting the evolution of material properties in the vicinity of surfaces with high friction in metal-forming processes.     

Design of reconfigurable antennas based on an L-shaped slot and PIN diodes for compact wireless devices

A basic antenna structure to design pattern and pattern/frequency reconfigurable antennas is proposed. The structure consists of an L-shaped slot, PIN diodes, lumped capacitors and bias networks. The PIN diodes and the lumped capacitors located at specific positions are used to create short circuits across the slot. By carefully controlling these diodes, the induced current distribution around the slot can be changed, resulting in different antenna radiation patterns. Thus, a pattern reconfigurable antenna can be achieved. The proposed structure is then extended to design frequency/pattern reconfigurable antennas by introducing varactor diodes. Two compact reconfigurable antennas based on the proposed structure are designed and implemented to prove the design concepts. The experiment results fully demonstrated the performances of the proposed designs. Owing to the compact size and ease on manufacture, the proposed structure can be a promising solution in compact wireless devices such as smart phones and notebook computers.     

FACE: Fine-tuned Architecture Codesign Environment for ASIP Development

High-performance, reliable, and robust products with a short development schedule are general design aims. FACE was developed to achieve these goals, including the organization of a design flow, a frequency-driven information analyzer, compiler techniques (code generator and instruction optimization), and a hierarchical object design library. This paper explores the design space of a retargetable compiler and a reconfigurable hardware, which combine both software and hardware reprogrammability. The environment, FACE, we have developed allows us to quickly move the functions between software and hardware in a state of flux. Finally, it generates the application specific integrated processor (ASIP) and a compiler for the new ASIP architecture. The case study is considered which demonstrates the efficiency in ASIP design of FACE.     

Fractal image compression with simple classification scheme infrequency domain

In fractal image compression, the mean squared error (MSE) computations of the eight orientations of the domain blocks can be reduced into two groups of inner products in the frequency domain. A very simple classification scheme is presented for reducing the two groups of computations into one, which makes the encoder up to 4.7 times faster     

Antijam capability analysis of RS-coded slow frequency-hoppedsystems

The application of Reed-Solomon codes in slow frequency-hopped systems has been extensively studied. Earlier investigations assumed an infinite interleaving length and considered partial-band noise jammers only. This paper extends previous efforts by analyzing the effect of finite interleaving length and the impact of band multitone jammers. We also explain why two-threshold (2T) erasure-insertion methods (EIM) are needed and examine their performance. Numerical results are presented to compare the effectiveness of the EIM and jammer types and to study the relationships among the hop rate, the interleaver size, and the code rate. The use of 2T-EIM necessitates the estimation of several additional channel and signal parameters. Simple and effective estimation algorithms are provided as well     

Guest-host ferroelectric side-chain liquid crystalline polymeric materials with improved electro-optical properties

A ferroelectric side-chain liquid crystalline polysiloxane (FLCP) containing azobenzene dyes as guest molecules for electro-optics has been investigated. The intensity and frequency of the Goldstone mode for the FLCP were increased remarkably after doping with azobenzene dyes. Larger fluctuation of the spontaneous polarization vector in each smectic layer under an applied electric field can be brought about with the addition of a strong dipole-moment guest molecule. This leads to a larger spontaneous polarization and shorter response time. It was found that the doping of a suitable amount of a strong dipole-moment azobenzene dye in the LC phase of the FLCP is helpful for the improvement of the electro-optical properties.     

Piezoviscous Effects in Nonconformal Contacts Lubricated Hydrodynamically

The analysis in this Paper is concerned with the piezoviscous-rigid regime of lubrication for the general case of elliptical contacts. In this regime, several, formulas of the lubricant film thickness have been proposed. However, either the load parameter W is not included, which has a strong effect on film thickness, or the film thickness is overestimated by using the Barus formula for pressure viscosity characteristics. In the current study, the Roelands formula has been used for the pressure-viscosity relationship. The effects of the dimensionless load, speed, and materials parameters, the radius ratio, and the lubricant entrainment direction have been investigated. Forty-one cases were used in obtaining the minimum film thickness formula: H₀ = 178G^0.386U^1.266W^?0.880 (1 ? e^?0.0387α Contour Plots indicate in detail the pressure developed between the contacting solids.     

Effects of ambient illuminance and electronic displays on users' visual performance for young and elderly users

Abstract— This study investigated the effects of age (young participants aged 20–30 and elderly participants older than 60), ambient illuminance (50, 500, 1 500, 3000, 6000, and 9000 lx) on participants' visual performance when using various electronic displays (conventional transmissive LCD, Ch‐LC display, and E‐ink display). Overall, the results indicated that participants' visual performance showed sign if icant difference among various ambient il luminance cond itions, electronic displays, and between two groups of participants. Significantly different visual performance was observed between young and elderly participants. The interaction among ambient illuminance, type of electronic display, and age had a significant effect on participants' visual performance. When participants used the E‐ink display, both young and elderly participants had significantly worse visual performance under an ambient illuminance of 50 lx compared to other illuminance settings. When participants used the Ch‐LC display, young participants had significantly worse visual performance under an ambient illuminance of 50 lx compared to other illuminance settings, but elderly participants had significantly better visual performance under an ambient illuminance higher than 1500 lx. When young participants used a conventional transmissive LCD, the ambient illuminance had no significant effect on their visual performance. When elderly participants use a conventional transmissive LCD, an illuminance of 50 and 6000 lx seem to have a detrimental effect on their visual performance.     

Modeling, qualitative analysis, and performance evaluation of theetching area in an IC wafer fabrication system using Petri nets

Integrated circuit (IC) wafer fabrication systems can be characterized as discrete event systems. Petri nets are tools that have been successfully used to model and analyze such systems. This paper reports a project of applying Petri net methodologies to detailed modeling, qualitative analysis, and performance evaluation of the etching area in a real-world IC wafer fabrication system located in Taiwan's Hsinchu Science-Based Industrial Park, To tackle the problem of building a large and complex system model, a synthesis technique is used. The resultant extended net model is checked for important qualitative properties in manufacturing. A simple control policy for deadlock prevention is proposed. To obtain performance measures, simulation is used. The simulation result shows that except a small number of machines, the errors between the simulated and actual utilizations are less than 5%, The validated model can be used to answer many “what-if” questions, such as predicting the maximal throughput and bottleneck machines