Impact of channel estimation error on channel capacity of multiple input multiple output system

In order to investigate the impact of channel estimation error on channel capacity of multiple input multiple output （MIMO） system, a novel method is proposed to explore the channel capacity in correlated Rayleigh fading environment. A system model is constructed based on the channel estimation error at receiver side. Using the properties of Wishart distribution, the lower bound of the channel capacity is derived when the MIMO channel is of full rank. Then a method is proposed to select the optimum set of transmit antennas based on the lower bound of the mean channel capacity. The novel method can be easily implemented with low computational complexity. The simulation results show that the channel capacity of MIMO system is sensitive to channel estimation error, and is maximized when the signal-to- noise ratio increases to a certain point. Proper selection of transmit antennas can increase the channel capacity of MIMO system by about 1 bit/s in a flat fading environment with deficient rank of channel matrix.     

基于S7-200 PLC和TP170A的船舶中央空调综合控制系统的实现

本文利用S7-200PLC实现船舶中央空调的综合控制和管理，对制冷压缩机进行有级能量调节，温度和湿度实现PID和PWM控制，达到了节能和操作方便的效果。     

中原城市群道路交通与土地利用互动关系研究

文章运用系统分析法及文献资料法分析了中原城市群土地利用与道路交通的特点以及二者的互动关系。分析认为:中原城市群的建设用地矛盾突出,土地利用集约化程度不高;道路交通条件的改善促使本地土地价格上涨,加速了城市边缘区土地的开发;土地的开发利用,产生了巨大的交通需求,道路交通的增长不能完全满足高强度土地开发利用的需求。     

厂拌热再生设备选型对沥青混合料再生质量影响探析

本文就沥青厂拌热再生设备选型进行阐述,探讨了不同种类厂拌热再生设备对沥青混合料的再生技术产生的作用等。并由此对高等级公路沥青路面养护维修工程中沥青混合料再生利用技术的完善具有一定参考价值。     

Merging bus routes in Hong Kong’s central business district: Analysis and models

A significant portion of the 200,000 people working in Hong Kong’s central business district (CBD) relies on buses as their primary means of transport. During peak hours, nearly a thousand double-decker buses pour into a tiny area of 150 ha. This causes traffic congestion and air pollution. Moreover, given that the flow is uni-directional (into the CBD in the morning and out of the CBD in the afternoon), the occupancy of buses in the CBD is actually low.In this paper, we propose to reduce traffic congestion and to increase bus occupancy by merging bus routes. We describe the peculiar situation of the CBD in Hong Kong and explain the necessary conditions for the possible success of merging routes. Our analysis shows that merging will lead to an overall benefit for all parties, including government, bus operators, and passengers. The actual merging decisions, which routes to merge and at what frequencies buses should run, are determined by a mathematical model. The model also shows quantitatively the benefits of merging routes and the impacts of other factors. The procedure that we follow and the model that we adopt can be applied to other CBD.     

武汉市中环线西环段8+725～9+030段软基处理

武汉市中环线西环段途径沟渠纵横 ,湖塘发育的地区 ,其土壤含水量大、孔隙率高。如何处理好软土地基是设计中的一个关键问题。本文结合在 8+72 5～ 9+0 3 0段软基采用粉喷桩处理的工程实践 ,对处理情况作了分析 ,并就粉喷桩设计、施工、补强和检测中的有关问题进行探讨。     

中海达海洋导航软件的数据处理方法

在水深测量监理的工作中,水深数据的处理是工作的难点。文章通过对常用的水深测量导航软件＂中海达海洋测量导航软件＂的数据处理方法研究,开发出了该常用导航软件的数据处理方法程序,解决了水深测量监理中的关键难点。     

广西高速公路中央分隔带景观绿化设计探讨

文章针对广西高速公路中央分隔带景观绿化设计现状,提出了高速公路中央分隔带景观绿化设计形式及思路,着重对绿化布置形式及防眩设计进行了探讨。     

Assessment of port economic impacts on regional economy with a case study on the Port of Lisbon

This article presents a method of assessing the economic impacts of ports at both regional level and national level, through application of input–output analysis. To this end, a methodology for data collection is proposed, which combines a top-down with a bottom-up approach which should help in surpassing some of the difficulties commonly faced in port economic impact studies. The presented methodology allows port planners and policymakers to assess the economic significance and geographic reach of port investments. This study considers the economic impacts of the port cluster and the socio-economic significance of port user industries. The several layers of the analysis are kept separate to allow a better grasp of direct and indirect impacts. The proposed methodology is demonstrated in a study of the Port of Lisbon, which confirms the significance of this port to the Portuguese economy, and also demonstrates that the influence of the Port of Lisbon is mostly limited to an area in close proximity to the port. Therefore, results suggest that investments for the development of logistic infrastructures associated with the port should concentrate in the immediate hinterland of the port.     

中央自动充放气铜管开裂失效分析

通过对中央充放气铜管宏观检查、化学成分分析、硬度测试、氨熏试验等结果分析,确定了其开裂原因是由于工件冷变形后未消除残余应力,加之装配后产生的应力,在露天放置又受到大气雨水等共同作用,形成了腐蚀环境,导致产生应力腐蚀裂纹。并提出了去应力退火预防中央充放气铜管开裂,效果良好。