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991.
We present a formal approach to study the evolution of biological networks. We use the Beta Workbench and its BlenX language to model and simulate networks in connection with evolutionary algorithms. Mutations are done on the structure of BlenX programs and networks are selected at any generation by using a fitness function. The feasibility of the approach is illustrated with a simple example. 相似文献
992.
A residual-based moving block bootstrap procedure for testing the null hypothesis of linear cointegration versus cointegration with threshold effects is proposed. When the regressors and errors of the models are serially and contemporaneously correlated, our test compares favourably with the Sup LM test proposed by Gonzalo and Pitarakis. Indeed, shortcomings of the former motivated the development of our test. The small sample performance of the bootstrap test is investigated by Monte Carlo simulations, and the results show that the test performs better than the Sup LM test. 相似文献
993.
Yunfeng GuAuthor Vitae Azzedine BoukercheRegina B. AraujoAuthor Vitae 《Journal of Parallel and Distributed Computing》2008
Data distribution management (DDM) plays a key role in traffic control for large-scale distributed simulations. In recent years, several solutions have been devised to make DDM more efficient and adaptive to different traffic conditions. Examples of such systems include the region-based, fixed grid-based, and dynamic grid-based (DGB) schemes, as well as grid-filtered region-based and agent-based DDM schemes. However, less effort has been directed toward improving the processing performance of DDM techniques. This paper presents a novel DDM scheme called the adaptive dynamic grid-based (ADGB) scheme that optimizes DDM time through the analysis of matching performance. ADGB uses an advertising scheme in which information about the target cell involved in the process of matching subscribers to publishers is known in advance. An important concept known as the distribution rate (DR) is devised. The DR represents the relative processing load and communication load generated at each federate. The DR and the matching performance are used as part of the ADGB method to select, throughout the simulation, the devised advertisement scheme that achieves the maximum gain with acceptable network traffic overhead. If we assume the same worst case propagation delays, when the matching probability is high, the performance estimation of ADGB has shown that a maximum efficiency gain of 66% can be achieved over the DGB scheme. The novelty of the ADGB scheme is its focus on improving performance, an important (and often forgotten) goal of DDM strategies. 相似文献
994.
Behaviour based on decision matrices for a coordination between agents in a urban traffic simulation
René Mandiau Alexis Champion Jean-Michel Auberlet Stéphane Espié Christophe Kolski 《Applied Intelligence》2008,28(2):121-138
This paper describes a multi-agent coordination mechanism applied to intersection simulation situations. In a goal of urban
traffic simulation, we must consider the dynamic interactions between autonomous vehicles. The field of multi-agent systems
provides us some studies for such systems, in particular on the coordination mechanisms. Conflicts between vehicles (i.e.
agents) are very frequent in such applications, and they may cause deadlocks, particularly at intersections such as crossroads.
Our approach is based on the solving of two player games/decision matrices which characterize three basic situations. An aggregation
method generalizes to n-player games for complex crossroads. The objective of this approach consists in searching basic two-player
matrices for solving n-agent problems. To explain the principle, we describe our approach for a particular case of crossroad
with three agents. Finally, the obtained results have been examined via a tool of road traffic simulation, ARCHISIM. We assume
also that the global traffic replicates the behavior of agents in different situations. 相似文献
995.
Ian Streeter Gregory G. Lidong Richard G. Compton 《Sensors and actuators. B, Chemical》2008,133(2):462-466
Cyclic voltammetry is recorded of the oxidation of ferrocyanide on a glassy carbon electrode modified with multiple layers of single-walled carbon nanotubes. The current response is interpreted in terms of semi-infinite planar diffusion towards the macro-electrode surface and in terms of oxidation of the electroactive species trapped in pockets in between the nanotubes. A thin layer model is used to illustrate the effects of diffusion within a porous layer. It is found that a semi-infinite planar diffusion model alone is not appropriate for interpreting the kinetics of the electron transfer at this electrode surface. In particular, caution should be exercised in respect of comparing voltammetric peak-to-peak potential separations between naked electrodes and nanotube-modified electrodes for the inference of electrocatalysis via electron transfer via the nanotubes. 相似文献
996.
Due to the increasing deployment of conversational real-time applications like VoIP and videoconferencing, the Internet is
today facing new challenges. Low end-to-end delay is a vital QoS requirement for these applications, and the best effort Internet
architecture does not support this natively. The delay and packet loss statistics are directly coupled to the aggregated traffic
characteristics when link utilization is close to saturation. In order to investigate the behavior and quality of such applications
under heavy network load, it is therefore necessary to create genuine traffic patterns. Trace files of real compressed video and audio are text files containing the number of bytes per video and audio frame. These can serve
as material to construct mathematical traffic models. They can also serve as traffic generators in network simulators since
they determine the packet sizes and their time schedule. However, to inspect perceived quality, the compressed binary content
is needed to ensure decoding of received media. The EvalVid streaming video tool-set enables this using a sophisticated reassembly
engine. Nevertheless, there has been a lack of research solutions for rate adaptive media content. The Internet community fears a congestion collapse if the usage of non-adaptive media content continues to
grow. This paper presents a solution named Evalvid-RA for the simulation of true rate adaptive video. The solution generates
real rate adaptive MPEG-4 streaming traffic, using the quantizer scale for adjusting the sending rate. A feedback based VBR
rate controller is used at simulation time, supporting TFRC and a proprietary congestion control system named P-AQM. Example
ns-2 simulations of TFRC and P-AQM demonstrate Evalvid-RA’s capabilities in performing close-to-true rate adaptive codec operation
with low complexity to enable the simulation of large networks with many adaptive media sources on a single computer. 相似文献
997.
随着消费电子技术的飞速发展,SD卡也被越来越广泛的应用到各种终端设备上.在消费电子产品设计中,存储接口方面对SD卡的支持也是重点的考虑.但是在许多主控芯片中,并没有集成SD卡硬件控制器,这时基于GPIO来使用软件实现SD总线对SD卡的读取就显得尤为重要了.本文研究并实现了使用GPIO来模拟SD总线技术,并分析了优化方法及实验结果. 相似文献
998.
水声通信网络信道仿真研究 总被引:1,自引:0,他引:1
根据海洋环境下水声信道的特性,提出一个面向水声通信网络信道的仿真框架,其中包括传播延迟、接收功率、背景噪声、干扰噪声、信噪比与误码率等若干模型,并以一个典型的水声网络仿真场景为例,给出了部分仿真试验结果. 相似文献
999.
电磁频谱是一个充满神奇的无形世界,是无线电通信的基础。随着电子技术在各个领域的广泛应用,电子装备的种类不断增多,频谱利用越来越拥挤,电磁频谱的管理显得更为重要。能否掌握电磁频谱的控制权,科学有序地使用频率,使各种武器装备合理使用,形成一个统一的整体,将直接影响信息的传递质量。因此,只有加强无线电频谱管理,才能最大限度地避免电磁环境的恶化和电磁干扰的产生,提高信息传递的质量和效率。 相似文献
1000.
为了评估MapleSim建模与仿真软件性能。该文简要介绍了MapleSim及其特点并阐述了MapleSim进行建模分析的步骤。并实验用MapleSim对一个机械系统和模拟电路信号产生电路建模仿真和分析,比较不同实验情况结果和提取系统方程。结果表明MapleSim是一个优秀的、直观快捷的高性能多领域复杂系统物理建模仿真分析工具。实验有指导意义。 相似文献