基于复合式抛物面聚光器的LED反光杯建模研究

针对复合式抛物面聚光器(CPC)无法在TracePro软件中直接建模的不足,结合TracePro软件特点,对CPC关键参数进行了分析,通过数学模型对参数之间的几何关系进行了推导,得出了计算公式,实现了CPC在TracePro中的建模。将CPC设计成反光杯应用于LED灯具中,可方便地进行光学模拟和分析,进而有效地缩短产品开发周期和开发成本。为CPC设计提供了数学依据,通过建模验证了该方法的可行性,有效提高了设计效率。结果表明,用通过该方法设计出的CPC做成的LED反光杯,可以极大地提高灯具的发光效率。为其在照明领域的发展应用提供了更好的使用价值和前景。     

一种基于QoS的无线Mesh网络DSR路由优化算法

无线Mesh网络(Wireless Mesh Network,简称WMN)是一种新型的高容量、高速率的分布式宽带无线网络,是下一代无线网络的关键技术。在综合考虑带宽、传输拥塞、网络吞吐量等方面因素,将博弈论的思想引入动态源路由(Dynamic Source Routing,简称DSR)算法中,提出一种基于博弈论的DSR路由优化算法,经分析与仿真表明,该路由能有效减小时延,提高数据传输效率,提升网络传输的服务质量(Quality of Service,简称QoS)。     

Performance Analysis of Full-Duplex Vehicle-to-Vehicle Relay System over Double-Rayleigh Fading Channels

Mobile Networks and Applications - In this paper, we study the performance of a full-duplex (FD) relay system in vehicle-to-vehicle (V2V) communication. In this relay communication system, the...     

Linearization of RF Power Amplifiers in Wideband Communication Systems by Adaptive Indirect Learning Using RPEM Algorithm

Mobile Networks and Applications - This paper proposes a new approach of digital predistortion (DPD) technique based on the adaptive indirect learning architecture (ILA) by using a recursive...     

Part II: An example of the use of the comsis software: simulation of an optical network which uses wavelength multiplexing,fsk modulation format and direct detection

This second article deals with using the Comsis software for a particular application. Simulation is used to determine the maximum channel density in presence of crosstalk. In a first part, the modelling of the system is described. The simulation parameters of different optical elements are given. The results show that in the case of channels modulated at 500 Mbitls using fsk modulation format, and a direct detection operation at 1,5 μm, a minimum spacing of 6 GHz can be obtained with a 2 dB penalty. Thus if only the bandwidth of the erbium doped fibre amplifier is taken into account, the maximum number of channels which can be used is 250. However if the fsr (free spectral range) of optical filter is taken into account, the maximun number of channels is limited to 30.     

Les enjeux économiques de ľinterconnexion des réseaux

The network interconnection and its regulation consist in solving the following dilemma: increase competition and preserve the universal service through access charges, which symbolizes today institutional organization within the telecommunication industry. This paper presents some of the economic and social factors that drive the interconnection policies namely ona (open network architecture) in the United States, or onp (open network provision) in Europe. In the first section, we list some social and economical issues related to open network policies. In the second section, we study the different answers brought up by the regulator through alternative interconnection price formulas. In conclusion, we discuss the stakes and risks of interconnection, while the technological evolution of network introduces intelligent software in switching équipement and implements the tremendous abilities of the digital broadband networks.     

Locations and amplitudes of the extrema of the sinx/x function

This paper addresses the calculation of the extrema of the sin x/x function. First the Newton-Raphson method is used, which allows us to obtain the extrema locations very fast through the use of a recursion formula. Then a second approach is proposed, which gives the extrema locations and the extrema amplitudes in the form of series expansions. Simple, accurate algebraic expressions are derived.     

Extending the Kernighan/Lin Heuristic for Hardware and Software Functional Partitioning

The Kernighan/Lin graph partitioning heuristic, also known as min-cut or group migration, has been extended over several decades very successfully for circuit partitioning. Those extensions customized the heuristic and its associated data structure to rapidly compute the minimum-cut metric central to circuit partitioning; as such, those extensions are not directly applicable to other problems. In this paper, we extend the heuristic for functional partitioning, which in turn can solve the much investigated codesign problem of partitioning a system's coarse-grained functions among hardware and software components. The key extension customizes the heuristic and data structure to rapidly compute execution-time and communication metrics, crucial to hardware and software partitioning, and leads to near-linear time-complexity and excellent resulting quality. Another extension uses a new criteria for terminating the heuristic, eliminating time-consuming and unnecessary fine-tuning of a partition. Our experiments demonstrate extremely fast execution times (just a few seconds) with results matched only by the slower simulated annealing heuristic, meaning that the extended Kernighan/Lin heuristic will likely prove hard to beat for hardware and software functional partitioning.     

A full-wave analysis of interconnection planar lines applications to structures with finite ground plane

The high integration level associated to the increase of the operating frequency of microelectronic integrated circuits create complex electromagnetic coupling in the interconnection lines which lead to mismatch and frequency dispersion. In the present paper, we propose a full-wave analysis to characterise the electromagnetic behaviour of interconnection planar lines using mixed-potential integral equations technique. The theoretical and numerical treatments of Green’s functions for the specific structures are firstly presented. The calculated results for parallel and coplanar strips are compared to the published ones. The effect of the finite ground plane on the propagation constant and the characteristic impedance is then analysed for different permittivities. The obtained theoretical and experimental results for the reflection coefficient of straight resonators confirm finally the observed effect of the finite ground plane on the frequency dispersion and the scattering characteristics.