Modéles de lignes simples et couplées,idéales et à pertes,pour la CAO des circuits gigabits

This paper describes the principles underlying a library of single and coupled lines, ideal or lossy for the cad of interconnections in gigabit logic circuits. The models are based upon the quasi-TEM approximation, they exploit the method of characteristics and direct simulation in the time domain which give good calculation efficiency. The modeling of lossy coupled lines is original and utilizes modal decomposition in the time domain which may be performed in good approximation for coupled lines of equal widths. The models are integrated in the circuit simulator Macpro to perform the cad of circuit microstrip interconnections. Simulations including the response of the instrumentation are compared with the corresponding measurements on typical configurations of lossy coupled lines deposited on a semi-insulated GaAs substrate.     

Influence of glycerol on the mechanical reversibility and thermal damage susceptibility of collagenous tissues

Clinical procedures wherein supraphysiologic temperatures must be achieved in deep layers of tissue via light are often compromised by optical scattering and absorption. Optical clearing of tissue superficial to the target improves the efficacy of such procedures. Glycerol is an attractive chemical agent for achieving dramatic reductions in tissue turbidity, but its net effects on healthy tissue are not fully understood. In this paper, we investigate possible alterations of biaxial mechanical properties in a model collagenous tissue, bovine epicardium, induced by glycerol. Furthermore, we examine the effects of glycerol on the biaxial thermomechanical properties of epicardium constrained at near-physiologic length. It is seen that mechanical changes induced by glycerol are fully reversed upon rehydration in normal saline. Moreover, glycerol protects cleared tissue by increasing its thermal stability and minimizing thermal alterations of mechanical properties.     

Hybrid verification integrating HOL theorem proving with MDG model checking

In this paper, we describe a hybrid tool for hardware formal verification that links the HOL (higher-order logic) theorem prover and the MDG (multiway decision graphs) model checker. Our tool supports abstract datatypes and uninterpreted function symbols available in MDG, allowing the verification of high-level specifications. The hybrid tool, HOL-MDG, is based on an embedding in HOL of the grammar of the hardware modeling language, MDG-HDL, as well as an embedding of the first-order temporal logic L_mdg used to express properties for the MDG model checker. Verification with the hybrid tool is faster and more tractable than using either tools separately. We hence obtain the advantages of both verification paradigms.     

Network management in a fast packet environment

StrataCom specializes in Asynchronous Transfer Mode (ATM) technology — a method of rapid wide-area distribution of all forms of traffic in cell format. This article will look at how StrataCom approaches network management for ATM switches.     

A Method for Quantification of the Effects of Size and Geometry on the Microstructure of Miniature Interconnects

Because the heterogeneity of microstructure has significant effects on the material properties of ultrafine interconnects, it should be quantified, to facilitate high-fidelity prediction of reliability. To address this challenge, a method based on autocorrelation and singular value decomposition is proposed for quantitative characterization of microstructure. The method was validated by developing a quantitative relationship between reported microstructure and tensile strength for SnAgCuRE solders reported in the literature. The method was used to study the effects of size and geometry in ultrafine Sn37Pb interconnects on microstructure and von Mises stress, which were obtained simultaneously by coupling a phase-field model with an elastic mechanical model. By use of this method the degree of heterogeneity of the microstructure in relation to preferred growth directions of the phases was quantified by use of a scalar microstructure index. It was found that microstructure heterogeneity increases with decreasing standoff height, and is higher for hourglass-shaped solder joints. The average von Mises stress was found to be positively related to the microstructure index. The strong correlation between microstructure index and average von Mises stress was confirmed by nonlinear regression analysis using an artificial neural network. This indicates that the mechanical behavior of ultrafine interconnects can be predicted more accurately on the basis of the microstructure index.     

Synchronization controller for a 3-R planar parallel pneumatic artificial muscle (PAM) robot using modified ANFIS algorithm

Parallel manipulator is a closed-kinematic chain mechanism in which performance of its end effector – moving platform is contributed by its independent actuators. In traditional designs, each elemental actuator has its own controller as well as reference input, and it works independently without gathering information from its neighbors. Consequently, as one of the actuators cannot keep up with the others, the platform performance is easily deteriorated due to the lack of coherence between these actuators. Therefore, the aim of this paper is to design a 3-R planar parallel robot and develop a proper synchronization controller for its tracking control task. Adaptive Network Based Fuzzy Inference System (ANFIS) algorithm was modified and applied as the main strategy of this synchronization controller. The controller is then able to compensate errors between the actuators and enforce them to cooperate harmonically with each other regardless external disturbances caused by the outside environment or geometrical constraints of the closed-loop structure. Simulations and practical experiments on a scaled parallel robot were carried out to evaluate the designed controller. The results showed that by applying the proposed control technique, the working errors of the component actuators converged quickly to zero almost at the same time. As a result, the tracking performance of the common platform was significantly improved in comparison with the performance when applying a non-synchronization controller. The proposed method is effective in controlling systems which require collaborations between the sub-agents.     

Enhanced carrier mobility and photon-harvesting property by introducing Au nano-particles in bulk heterojunction photovoltaic cells

In this study, polymer solar cells (PSCs) doped with Au nanoparticles (Au NPs) were successfully fabricated to maximize the photon-harvesting properties on the photoactive layer. In addition, a conductivity-enhanced hybrid buffer layer was introduced to improve the photon absorption properties and effectively separate the generated charges by adding Au NPs and dimethylsulfoxide (DMSO) to the PH 500 as a buffer layer. The PSC performance was optimized with a 88% improvement over the conventional PSCs (photoactive area: 225 mm², power conversion efficiency (PCE): 3.2%) by the introduction to the buffer layer of Au NPs and DMSO at 10 wt% and 1.0 wt%, respectively, and with 15 wt% Au NP doping in the photoactive layer. The internal resistance was decreased due to the increased photocurrent caused by the localized surface plasmon resonance (LSPR) effect of the Au NPs in the photoactive layer and by the improvement of carrier mobility induced by the DMSO doping of the buffer layer. As a result, the series resistance (R_S) deceased from 42.3 to 19.7 Ω cm² while the shunt resistance (R_SH) increased from 339 to 487 Ω cm².     

Linux安全吗？

＂Linux安全吗？＂老实说,这是一个很有问题的问题,这就好比质疑我的财务和医疗记录是否安全,或是所有储存在＂云计算＂的数据是否安全？同样的,我要如何确定我的桌面计算机和我的手机是否都安全无虞？甚至更扩大一点来说,遍布我们生活周遭的智能电网,以及其他林林总总的公共基础设施,是否也都安全呢？我们是不是该拨个时间好好担心一下这些问题？     

Predictors of support for doctoral programs in media information technologies

This study assesses interest in curricular development in new technologies among communication faculty, with a focus on doctoral-level programs. Diffusion of innovations theory explains both individual- and organizational-level factors that may account for adoption of innovations, including those stemming from new technologies. In the field of communication, media information technology programs represent an organizational-level innovation of clear importance but with uncertain faculty support, due to individual factors (e.g., interest area, age) and departmental constraints (e.g., lack of resources). In light of this, several research questions are advanced to address: (1) the current level of support for media information technology programs among communication faculty members and (2) predictors of faculty interest in having more media information technology programs. Data were collected through a random sample of faculty members who filled out a survey on the World Wide Web. Results indicate that media information technology programs are viewed by faculty as the most needed type of program in the field of communication. Findings from a logistic regression analysis also reveal several predictors of support for new technology programs, including male gender, support for organizational communication programs, support for programs focusing on mass communication, and the belief that multimedia teaching facilities are important. The implications of these findings are discussed, with an emphasis on their relevance to faculty working in communication and related fields.     

A novel bulk-input low voltage and low power four quadrant analog multiplier in weak inversion

A new four quadrant voltage mode bulk input analog multiplier is presented .The proposed multiplier is designed to operate in weak inversion. Multiplication is done by driving the bulk terminals of the MOS devices which offers linear dynamic range of ±80 mV. The simulation shows, it has a linearity error of 5.6 %, THD of nearly 5 % and ?3 dB band width of 221 kHz. Total power consumption is very low i.e. 714 nW. The circuit operates at a supply voltage of 0.5 V and is designed using 180 nm CMOS technology. It is suitable for low power bioelectronics and neural applications.