Multiple Experiment Environments for Testing

Concurrent simulation (CS) has been used successfully as areplacement for serial simulation. Based on storing differences fromexperiments, CS saves storage, speeds up simulation time and allowsexcellent internal observation of events. In this paper, we introduceMultiple Domain Concurrent Simulation (MDCS) which like concurrentsimulation, maintains efficiency by only simulating differences. MDCS alsoallows experiments to interact with one another and create new experimentsthrough the use of domains. These experiments can be traced and observed atany point, providing insight into the origin and causes of new experiments.While many experiment scenarios can be created, MDCS uses dynamic spawningand experiment compression rather than explicit enumeration to ensure thatthe number of experiment scenarios does not become exhaustive. MDCS does notrequire any pre-analysis or additions to the circuit under test. Providingthis capability in digital logic simulators allows more test cases to be runin less time. MDCS gives the exact location and causes of every experimentbehavior and can be used to track the signature paths of test patterns forcoverage analysis.We will describe the algorithms for MDCS, discuss the rules forpropagating experiments and describe the concepts of domains for makingdynamic interactions possible. We will report on the effectiveness of MDCSfor attacking an exhaustive simulation problem such as Multiple Stuck-atFault simulations for digital logic. Finally, the applicability of MDCS formore general experimentation of digital logic systems will be discussed.     

Robust blind PIC with adaptive despreader and improved interference estimator

An effective design of multistage parallel interference cancellation (PIC) receiver using blind adaptive (BA) despreader and pre‐respreader interference estimator for uplink CDMA is proposed and analysed. A novel algorithm is designed, which exploits constant modulus (CM) property of the users' transmitted signals and inherent channel condition to perform adaptive despreading based on minimum error variance criteria. This is carried out by BA weighting of each chip signal for accurate tracking of the desired user's signal power and hence for more improved data detection at the output of each stage of PIC. Furthermore, the despreader weights are used within the adaptive pre‐respreader interference estimation and cancellation to obtain online scaling factors during every symbol period, without any knowledge of users' channels or the use of training sequences. It is found that this way of estimation is optimal in minimum mean squared error sense, and hence, significant reduction in interference and noise variance is observed in detection and estimation of the desired users' signals compared with conventional PIC. Bit error probability of the proposed PIC is obtained using Gaussian Approximation method. Extensive simulation results are shown, which demonstrate impressive performance advantage in fading environments, high system loading, and severe near far conditions. Copyright © 2008 John Wiley & Sons, Ltd.     

ZnO Nanowires,Nanotubes, and Complex Hierarchical Structures Obtained by Electrochemical Deposition

Increasing the aspect ratio of ZnO nanostructures is one possible strategy to improve their thermoelectric properties. ZnO nanostructures with one-dimensional (1D) and three-dimensional (3D) morphologies were obtained using electrochemical deposition. Adjusting various deposition parameters made it possible to obtain arrays of vertically aligned ZnO nanowires (NWs) with controlled dimensions, density, and electrical properties. The concentrations of zinc or chloride ions in the solution were found to be key parameters. ZnO NWs were transformed into ZnO nanotubes (NTs), with an increased aspect ratio compared with the NWs, by selectively dissolving the core of the ZnO NWs in a concentrated KCl solution. The aspect ratio was strongly increased when the ZnO NWs were hierarchically organized in a 3D morphology. The synthesis of thin films composed of ordered hollow urchin-like ZnO NW structures was performed by combining the electrochemical deposition and polystyrene sphere templating methods. The electronic properties of the urchin-like ZnO structures were investigated by means of photoluminescence and transmission measurements.     

Smart water technology for leakage detection: feedback of large-scale experimentation

Recent advances in intelligent water meter technology have improved the quantitative monitoring in water supply and distribution systems. Smart meters using automated meter reading (AMR) technology allow water utilities to: (a) provide clear consumption patterns which can help customers to track and control their water usage and (b) improve active leakage targeting and leak detection capability. This paper presents a feedback about the use of AMR system to detect leakage in a large-scale experimentation, which is conducted at the Scientific Campus of the University of Lille, which stands for a small town of 25,000 users. This paper presents the demonstration site as well as its monitoring using AMR technology and how this technology allowed a rapid detection of water leakage.     

Large wavelength shifts in UV-exposed 3 dB and WDM fused taperfibre couplers

The spectral response of 3 dB and 1300/1550 nm wavelength division multiplexing fused taper fibre couplers can be shifted by over 100 nm by exposing the entire coupler with intense UV light at a wavelength of 193 nm and without prior hydrogenation. There is no discernable increase in excess loss. The major contribution to these shifts for these couplers originates in the down- and up-taper regions     

Nanostructure optical emitters based on quasibound electron energy levels

Given two energy states (levels) in a quantum well formed by two potential barriers of finite thickness, elementary quantum mechanics tells us that the lower energy state is more tightly bound than the upper state. This produces a longer spatial confinement lifetime in the lower state than in the upper state. This ratio of lifetimes is opposite to that needed for laser action between these states. Furthermore, the lifetime of the lower energy state must be significantly shorter than the electron scattering time for the upper state. These facts have blocked the development of lasers based on these transitions. However, in this paper we report experimental and analytical results on a versatile type of semiconductor heterostructure that overcomes these difficulties. Unlike previous devices, this structure relies on an optical transition between two states which are both above-barrier quasibound states in the ‘classical’ continuum. The oscillator strength is large and the operation of the device clearly demonstrates coherent electron wave behavior. Such structures could represent the basis for a new room-temperature infrared semiconductor laser.     

A renewable single-server queueing system with priorities

A single-server queue with a triple priority system is considered in this paper. The server can fail during its occupation time and is sent for repair immediately.The stationary probabilities of the different states of the system are studied, under the assumption that the arrival time and the service time for the three kinds of customers, and the repair time, all have Poisson distributions with different parameters. The results obtained before, in [Mokaddis et al., Eighth International Congress for Statistics, Computer Science, Social and Demographic Research, Vol. 4, pp. 31–58 (1983)] in the case of a double priority, are derived from the present results as special cases. Moreover the mathematical expectation of the number of customers and the average waiting time of both kinds of customers and more characteristics of the system, in the case of double priority, are obtained. Also, in this paper, we study the system without priority, in the cases of both a triple priority system and a double priority system.     

A new technique in a cutset evaluation

This paper presents a new technique (algorithm) for deducing minimal cutsets of 2-state systems by using minimal pathsets and vice-versa. An example is introduced to demonstrate the new technique.     

Sugar latexes as a new type of binder for water-based paint and coating

Sugar latexes based on saccharid derivatives, such as 3-MDG, 1- or 3-MDF and ITDF, have been synthesized in batch and semi-continuous emulsion polymerization. The polymerizations were carried out at 60 or 70°C, initiated by potassium peroxodisulfate, (KPS), in the presence of either ionic or non-ionic surfactant. The effect of the type and concentration of the surfactant and the type of polymerization process on the colloidal and rheological properties was studied. It was found that the particles size increased with using a non-ionic surfactant. Monodisperse particles were obtained by using SDS below its CMC, and smaller polydisperse latexes were observed when the SDS conc. was above the CMC. The latexes exhibit different non-Newtonian flows depending on the solid content and on the additives.