3G时代的GSM网发展策略研究

从2G网络的特点及与3G网络协调发展的角度出发,分析了3G时代中国联通2G网络的建设思路和策略,进而对提高2G网络资源利用率,确保投资有效性给出了一些建议。     

MiWAVE网络组网方案研究及建议

MiWAVE网络组网主要有三扇区组网和四扇区组网2种方案,这2种方案在国内外的无线通信网络中都有规模应用。通过规划软件仿真预测,从网络覆盖质量、干扰性能、商用经验等多方面对这些方案进行评估,并针对MiWAVE网络部署给出了具体的组网建议。     

Distributed In-Time Multiple Coverage Holes Healing Protocol

Coverage holes often appear in wireless sensor networks due to sensor failure or the inheritance of sensor＇s random distribution. In the hybrid model, mobile sensors in the network are acquired to heal coverage holes by their mobifity. When multiple coverage holes appear in the sensor network and each of them has a time requirement （in which the coverage hole has to be healed）, conflicts for the requests of the same mobile sensor may arise. A distributed multiple mobile sensor schedufing protocol （DMS） is proposed in this paper to solve this problem by finding mobile sensors in the time response zone defined by the time requirement of each coverage hole. Simulation results show that DMS can well schedule the mobile sensors to move to multiple coverage holes within the time requirement.     

A comparative study of indoor radon concentrations between dwellings and schools

The aim of this study is to determine the relationship of radon concentrations between dwellings and the schools located in the same regions and to obtain related indoor average radon concentration dwelling-school correction factor for similar locations. The research has been carried out by determining indoor radon concentrations at schools and dwellings located at the same districts in the selected two separate research fields called The Former Adapazari region and The New Adapazari region in the city of Adapazari using a total of 81 Cr-39 passive radon detectors for 75 days. The average radon concentrations have been determined for the dwellings and the schools in 15 districts of the Former Adapazari region as 59.9 Bq m⁻³ and 57.1 Bq m⁻³, respectively. The results in 4 districts of the New Adapazari region were 63.5 Bq m⁻³ for the dwellings and 61.0 Bq m⁻³ for the schools. Moreover, the annual effective doses were calculated as 1.33 mSv/y and 1.41 mSv/y for the dwellings of Former Adapazari and New Adapazari, respectively. It was seen that the doses received in the dwellings are about four times the doses received in the schools. The indoor radon concentration dwelling-school correction factor was found to be 1.04±0.01 for the research area.     

校园室内外大气PM2.5中的含碳气溶胶及室内源特征

分夏、冬季采集南昌大学前湖校区室外和3个不同室内环境中的PM2.5,测定有机碳(OC)和元素碳(EC),并分析室内、外碳气溶胶质量浓度及其分布特征;利用OC-EC关系式半定量分析室内排放源;结合室内、外二次有机碳(SOC)和SOC/OC的分布进一步讨论不同室内排放源的特征及对SOC的影响;对4个采样点的8个碳组分丰度特征比较分析,结果表明复印/打印机对室内OC的贡献高,8个碳组分的丰度分布特征与其它排放源具有较明显的差异。     

Novel sample preparation technique with needle-type micro-extraction device for volatile organic compounds in indoor air samples

A novel needle-type sample preparation device was developed for the effective preconcentration of volatile organic compounds (VOCs) in indoor air before gas chromatography–mass spectrometry (GC–MS) analysis. To develop a device for extracting a wide range of VOCs typically found in indoor air, several types of particulate sorbents were tested as the extraction medium in the needle-type extraction device. To determine the content of these VOCs, air samples were collected for 30 min with the packed sorbent(s) in the extraction needle, and the extracted VOCs were thermally desorbed in a GC injection port by the direct insertion of the needle. A double-bed sorbent consisting of a needle packed with divinylbenzene and activated carbon particles exhibited excellent extraction and desorption performance and adequate extraction capacity for all the investigated VOCs. The results also clearly demonstrated that the proposed sample preparation method is a more rapid, simpler extraction/desorption technique than traditional sample preparation methods.     

Locus: robust and calibration-free indoor localization,tracking and navigation for multi-story buildings

A fundamental goal of indoor localisation technology is to achieve the milestone of combining minimal cost with accuracy sufficient enough for general consumer applications. To achieve this, current indoor positioning systems need either extensive calibration or expensive hardware. Moreover, very few systems built so far have addressed floor determination in multi-story buildings. In this paper, we explain a Wi-fi-based indoor localisation, tracking and navigation system for multi-story buildings called Locus. Locus determines a device’s floor as well as location on that floor using existing knowledge of infrastructure, and without requiring any calibration or proprietary hardware. It is an inexpensive solution with minimum set-up and maintenance expenses, is scalable, readily deployable and robust to environmental changes. Experimental results in three different buildings spanning multiple floors show that it can determine the floor with 95.33% accuracy and the location on the floor with an error of 6.49 m on an average in real-life practical environments. We also demonstrate its utility via two location-based applications for indoor navigation and tracking in emergency scenarios.     

基于属性的形式验证技术及应用

为了提高产品的验证覆盖率和首次流片成功率,越来越多的验证技术和衡量标准被采纳。传统的仿真验证技术很难达到验证的快速收敛,而静态验证技术采用数学穷举的方法,利用断言对cornerco．se进行快速验证,有效避免了一些设计缺陷。Mentor公司的QuestaFormal工具可以对代码进行常规的功能检查,并可用Formal引擎证明设计代码及其断言的一致性,可极大地提高复杂设计的验证效率和鲁棒性。     

复杂SOC的软硬件协同验证解决方案

为了提高产品的验证覆盖率和产品的首次成功率,验证工程师越来越多的使用固件、硬件诊断程序和其它软件部分作为实际嵌入式处理器的SoC验证的激励,以保证RTL设计与最终设计实现的的应用环境相同,并覆盖更为复杂的场景,但该RTL验证环境对软件调试的可视性比较有限。Mentor公司的Questa Codelink提供了独特的软硬件协同验证的技术可以让验证人员同时看到软件的执行情况和与软件同步的硬件波形,其回放模式减少了仿真等待的时间,可以快速追踪并定位到程序出错的地方。Codelink也提供了多核调试的技术,可同时看到软件在不同处理器的执行情况,极大地提高了多核验证的效率。     

WCDMA室内信号覆盖系统及其可靠性分析

当前建设3G室内信号覆盖系统可选用多种信源方案和分布方式,针对这一现状,列举了一些室内覆盖方案,并对其系统可靠性进行了分析,指出过量采用没有蓄电池供电的RRU会影响系统的可靠性。