Successive beamforming,multiuser detection and diversity reception for multicarrier DS-CDMA system with antenna array

Code-Division Multiple-Access (CDMA) systems are interference limited,and therefore efficient interference management is necessary to enhance the performance of a CDMA system.In this paper,a successive beamforming (spatial filtering),linear decorrelating MultiUser Detection (MUD, temporal filtering) and diversity reception structure for uplink multicarrier Direct Sequence CDMA (DS-CDMA) system with antenna array are proposed.By beamforming,the antenna array suppresses interference according to the distinct array signature.Subsequently,linear decorrelating MUD is ap- plied to separate the signals of different users and eliminate Multiple Access Interference (MAI).Finally, the decorrelated signals at different subcarriers that belong to the same user are combined to achieve frequency diversity.Simulation results show that the proposed structure offers significant Bit Error Rate (BER) performance improvement by successively exploiting the space-time-frequency processing.     

Diversity of cultivable hydrogen-producing bacteria isolated from agricultural soils, waste water sludge and cow dung

This project aimed to study the diversity of cultivable hydrogen-producing bacteria, isolated from agricultural soils, waste water sludge and cow dung by analyzing 16S rRNA gene. Isolation performed anaerobically on nutrient agar using environmental samples as inoculum yielded 106 pure isolates. These isolates were tested for their capability to produce hydrogen. Then 16S rRNA gene of the 11 isolates having such ability were PCR amplified and subjected to restriction fragment length polymorphism (RFLP) analysis in order to group them into operational taxonomic units (OTUs). RFLP was evaluated for its ability to group the 1500-1600 bp PCR products into OTUs. Isolates were presumptively identified by analysis of partial 16S rRNA gene sequence data. Each OTU was found to be phylogenetically cohesive. The 11 isolates were put into 2 main groups. Group 1 composted of WS-2-2, AS_I-1 and AS_I-2 whose partial 16S rRNA genes showed similarity of 98-99% to members of the genus Paenibacillus. Group 2 composted of WS-4-2, Lao-1-2, WS-7-11, AS-1, AS-4, CD-5 and CD-6 having highest similarity of 98-99% to members of four genera in the family Enterobacteriacea. AS_I-2 which produced the highest amount of hydrogen gas of 2.70 ml had the highest 16S rRNA gene similarity of 99% to Paenibacillus polymixa.     

Diversity control in ant colony optimization

Optimization inspired by cooperative food retrieval in ants has been unexpectedly successful and has been known as ant colony optimization (ACO) in recent years. One of the most important factors to improve the performance of the ACO algorithms is the complex trade-off between intensification and diversification. This article investigates the effects of controlling the diversity by adopting a simple mechanism for random selection in ACO. The results of computer experiments have shown that it can generate better solutions stably for the traveling salesmen problem than AS_rank which is known as one of the newest and best ACO algorithms by utilizing two types of diversity.     

Patterning and predicting aquatic macroinvertebrate diversities using artificial neural network

A counterpropagation neural network (CPN) was applied to predict species richness (SR) and Shannon diversity index (SH) of benthic macroinvertebrate communities using 34 environmental variables. The data were collected at 664 sites at 23 different water types such as springs, streams, rivers, canals, ditches, lakes, and pools in The Netherlands. By training the CPN, the sampling sites were classified into five groups and the classification was mainly related to pollution status and habitat type of the sampling sites. By visualizing environmental variables and diversity indices on the map of the trained model, the relationships between variables were evaluated. The trained CPN serves as a 'look-up table' for finding the corresponding values between environmental variables and community indices. The output of the model fitted SH and SR well showing a high accuracy of the prediction (r>0.90 and 0.67 for learning and testing process, respectively) for both SH and SR. Finally, the results of this study, which uses the capability of the CPN for patterning and predicting ecological data, suggest that the CPN can be effectively used as a tool for assessing ecological status and predicting water quality of target ecosystems.     

移动机器人的路径规划与仿真

在机器人路径优化设计的研究中,由于应用环境存在障碍物,要求寻找最优无碰路径.针对于粒子群优化算法应用于移动机器人路径规划计算中,存在全局搜索能力弱,易出现早熟现象等问题,提出了一种QPSO算法的改进算法.采用8势阱模型的QPSO算法模型简单,控制参数少,全局搜索能力强,但存在早熟收敛的缺陷,从种群的多样性角度分析,在算法的迭代过程中,引入多样性函数,在种群的多样性小于dl.时,由多样性变异操作进行自适应调整,保持了种群中个体的差异性,避免算法陷入局部最优而出现早熟现象.在MATLAB平台上进行仿真,结果表明,改进算法能够有效地解决全局静态无碰路径优化问题,收敛速度、搜索质量与QPSO算法相比明显提高.     

基于改进QPSO算法的物流运输路径问题研究

传统的物流运输路径问题研究在模型建立上比较单一,难以满足物流运输的实际需要;路径搜索算法的全局搜索能力弱,并容易陷入局部极值点.为了有效的进行车辆调配,降低物流成本,提高企业的竞争能力,提出以物流运输成本最小化与顾客满意程度最大化为目标,借助权重系数变换法将多目标优化模型转换成单目标优化模型,并构造改进的QPSO算法进行求解.仿真结果表明,改进的QPSO算法在求解多配置中心多车辆的物流运输路径问题中呈现出了较好的稳定性与收敛速度,为运输路径优化提供了参考.     

日本多摩新城第15住区的实验

本文介绍日本多摩新城第15住区的开发思路、设计组织模式和设计理念。该住区的实例对中国当前的住宅开发具有参考价值。     

办公建筑表皮形式的生态剖析

本文以适宜技术下生态表皮的可变性措施为切入点，结合工程实例探讨办公建筑生态表皮对建筑立面形式的多样性与动态性表达的影响，以此来解读生态策略与形式表达相结合的发展趋势。     

Performance of Broadcast and Multicast Service with Interference Cancellation Based on Macro Diversity

The cdma2000 1xEV-DO mobile communication system provides broadcast and multicast services(BCMCS) to meet an increasing demand for multimedia data services.Single frequency network(SFN) is recognized as an effective way to improve the spectral efficiency of the BCMCS system.To improve the coverage and the data rate of the BCMCS users,an interference cancellation algorithm based on macro diversity is introduced in this paper.The performance of BCMCS in CDMA2000 EV-DO networks under the condition of SFN is evaluated.The simulation results show a significant improvement in bit error ratio(BER) while quantitatively validating the efficiency of our approach.     

The limits to shaping diversity as public culture: Permanent festivities in Barcelona

In spite of the existence of an extensive debate on cultural policies on the one hand, and on local diversity policies on the other hand, there are still few studies dealing directly with this nexus. This emerging research trend will be discussed in the context of Barcelona and through the analysis of a specific cultural policy field: the planning of permanent festivities.After overviewing its migration history and after presenting the theoretical framework and methodology, this article frames Barcelona’s general cultural policy and intercultural policy patterns, arguing that the Catalan capital is really at a very initial stage of connecting diversity with cultural policy. After that, I will defend the argument that, in spite of recognising diversity, the analysis of Barcelona’s permanent festivities shows that there are also some limits to the development of this connection, due primarily to a lack of democratization of culture. Interviews and a discussion group confirm this empirical diagnosis. The argument I want to put forward is that this lack of participation of immigrants in cultural planning and diversity promotion is probably due to the fact that the two departments in the city represent, indeed, two approaches toward the question of how to promote the nexus between culture and diversity, and thus they are still working separately. The department of culture still has an elitist focus, centred on a culture of excellence, while the immigration department has a more social focus on cultural diversity.