深圳地铁9号线公用移动电话引入方案分析

基于地铁通信的特点,为促进公众移动电话系统与地铁专用通信系统更好的结合及合理布置。本文采用现场调研勘察,结合相关通信标准要求,对深圳地铁9号线公用移动电话引入设计方案进行研究。     

通信机房采用室外集装箱发电机组的分析

介绍了室外集装箱发电机组的市场应用状况,以及采用室外集装箱发电机组需要注意的问题,对室外集装箱发电机组与室内发电机组的技术性和经济性进行了对比分析,最后提出了通信局房采用室外集装箱发电机组的建议。     

地铁TD-LTE覆盖方案研究

结合实际工程案例,从链路损耗、切换、干扰等方面研究了TD-LTE在地铁民用通信系统中的覆盖方案,测试分析了LTE系统信号,并针对实现LTE的MIMO技术提出了建议。     

下一代5GHz WLAN标准802．11ac室内覆盖分析

在对下一代WLAN标准802．11ac增强技术特点和可用信道分析的基础上,对802．11aC标准草案要求的不同必选项设置,分析比较其在室内场景下的覆盖性能,并给出应用建议。     

浅谈室内分布系统WCDMA网络的底噪问题及处理方法

室内分布系统由于直放站、无源器件的引入,多系统合路等原因,易造成WCDMA基站底噪抬升,直接影响室内分布系统的覆盖效果、话务容量及数据业务速率.简要分析了室内分布系统底噪产生的原因,并通过案例讲解几种常见底噪抬升问题的处理,有效降低底噪,提升WCDMA网络服务质量.     

Inverse estimation of indoor airflow patterns using singular value decomposition

The fast pace in the development of indoor sensors and communication technologies is allowing a great amount of sensor data to be utilized in various areas of indoor air applications, such as estimating indoor airflow patterns. The development of such an inverse model and the design of a sensor system to collect appropriate data are discussed in this study. Algebraic approaches, including singular value decomposition (SVD), are evaluated as methods to inversely estimate airflow patterns given limited sensor measurements. In lieu of actual sensor data, computational fluid dynamics data are used to evaluate the accuracy of the airflow patterns estimated by the inverse models developed in this study. It was found that the airflow patterns estimated by the linear inverse SVD model were as accurate as those estimated by the nonlinear inverse-multizone model. For the zones tested, sensor measurements along on the walls and near the inlet and outlet provided the greatest improvement in the accuracy of the estimated airflow patterns when compared with the results using measurements from other locations.     

Monte Carlo方法模拟非直视紫外光散射覆盖范围

针对大气中紫外光散射通信的特点, 用Monte Carlo方法对紫外光非直视(NLOS) 通信三种工作方式的覆盖范围进行分析, 建立了基于Monte Carlo方法的NLOS紫外光传输模型.利用Monte Carlo模拟方法对三种NLOS散射方式的单次和多次散射路径损耗及覆盖范围进行模拟研究, 结果表明, 多次散射和单次散射的路径损耗基本一致, NLOS(a) 类全向发送全向接收通信方式覆盖范围最小但全方位性好, NLOS(b) 类定向发送全向接收通信方式的覆盖范围较大但有一定方向性, NLOS(c) 类定向发送定向接收通信方式的覆盖范围最大但有很强的方向性.     

Indoor radon survey in Eastern Sicily

Inhalation of radon (Rn-222) and its progeny is one of the most significant sources of natural radiation exposure of the population. Nowadays, high radon exposures have been shown to cause lung cancer and many governments all over the world have therefore recommended that radon exposures in dwellings and indoor workplaces should be limited. Radon levels in buildings vary widely from area to area depending on local geology. This paper presents the results of a long-term survey of radon concentrations carried out from 2005 till 2010 in schools and dwellings of Eastern Sicily, using the solid-state nuclear track detector (SSNTD) technique. The investigated area shows medium-high indoor radon concentrations, higher than the Italian average of about 70 Bq/m³, with peaks of 500 Bq/m³ or more in buildings near active faults. Fortunately, only a small fraction of the measurements, about 1.5% of total, was found greater than EU and Italian action limits for indoor and workplaces.     

Some heuristic methods for solving p-median problems with a coverage constraint

The aim of this paper is to solve p-median problems with an additional coverage constraint. These problems arise in location applications, when the trade-off between distance and coverage is being calculated. Three kinds of heuristic algorithms are developed. First, local search procedures are designed both for constructing and improving feasible solutions. Second, a multistart GRASP heuristic is developed, based on the previous local search methods. Third, by employing Lagrangean relaxation methods, a very efficient Lagrangean heuristic algorithm is designed, which extends the well known algorithm of Handler and Zang, for constrained shortest path problems, to constrained p-median problems. Finally, a comparison of the computational efficiency of the developed methods is made between a variety of problems of different sizes.     

空调系统清洗引起的污染分析

分析了在空调系统清洗中,由于不合适的清洗方法及清洗手段、不合适的清洗设备和清洗程序所引起的空调系统的再污染。提出空调系统清洗的规范和有序是我国新型的空调清洗行业健康发展的关键。