无线通讯网络的质量优化研究

随着移动用户的持续增加和移动业务的层出不穷，我国的GSM无线通讯网络运营与维护必将面临更多的网络优化内容，本文分高话务密度区GSM无线通讯网络优化、高层楼宇GSM无线通讯网络优以及高等院校GSM无线通讯网络优化三种情况，讨论GSM系统无线通讯网络的质量优化，分别剖析了三种不同环境的网络质量影响因素，并针对环境的特点给出了具体的网络优化方案，为移动通信服务的提升起到积极作用。     

GSM网络电表集抄系统的硬件结构设计

介绍了我国电力消费、GSM网络发展的现状,开发基于GSM网络电表集抄系统的意义。提出了基于GSM网络电表集抄系统硬件结构的设计方案,并给出了其简化结构图,分析了各硬件组成部分的设计理念,提出GSM网络电表集抄系统具有广阔的应用前景。     

GPRS技术及其在行业中的应用

随着时代的发展和科技的进步，基于GSM系统的通用分组无线业务GPRS在技术上已变得非常成熟，在性能上显示出很多优势，现已在社会诸多领域内得到广泛的普及和应用。本文从GPRS网络的特点出发，阐述在诸多行业的应用及实现方式，分析了利用GPRS网络发展移动数据业务的前景。     

浅谈铁路GSM-R

阐述GSM—R的应用现状及其被应用的必要性,从GSM—R的业务模型、网络特点、工作频率几方面介绍GSM—R技术,并分析GSM—R未来可扩展的需求。     

基于GSM无线通信网络优化相关问题的研究

随着我国通信事业的发展，GSM网络建设规模与日俱增，由于有限的无线频率资源对GSM网络发展的制约越来越大，对网络系统的质量要求越来越高，因此，优化GSM网络势在必行．通过分析GSM无线通信网络优化的概念，针对GSM无线通信网络优化过程中的数据采集、数据分析、优化方案制定、网络参数调整问题进行探讨，以期通过阐述降低运营成本，实现优质的网络服务。     

长春市区GSM双频网建设策略分析

市区网络覆盖一直是GSM网络建设的重点和难点,随着用户的增加和各种新的业务的推出,话务量增长明显,尤其是在人口密集的市区。由于市区基站选址困难,双频网建设是近几年网络扩容的首选。但是,随之由双频网切换带来的网络质量问题使GSM双频网络建设增加了难度。     

GPRS在企业远程数据传输中的应用

科技的飞快发展使得GSM系统的通用分组无线业务GPRS在技术上变得越渐成熟，在性能上越显优势，现已在社会诸多领域内得到广泛的普及和应用。本文将根据GPRS业务及网络发展情况进行深入探讨。     

GSM网络优化实战与探讨

设计并实现了一种多网元数据采集方案,实时获取GSM网络中各网元的性能数据：提出使用快速增量更新算法来处理网络性能数据,提高了数据处理的效率;同时提出将GSM网个时隙资源只分配给一个用户使用,提出一种基于低相关度训练序列设计（TSC）的多用户同时隙复用技术,从而显著增加全球移动通信系统（GSM）的网络容量,实现对GSM网络的优化。     

TD／GSM互操作质量提升策略

本文介绍TD网络相比GSM的差距，分析TD网络和GSM网络怎样有机的结合在一起，提出TD／GSM互操作应遵循的原则。     

GPRS网络规划

GPRS,即通用分组无线业务,是在现有的GSM移动通信系统基础上发展起来的一种移动分组数据业务,它通过在GSM数字移动通信网络中引入分组交换的功能实体,以完成用分组方式进行的数据传输与交换。它可以看作是对原有的GSM电路交换系统进行的业务扩充,以支持移动用户利用分组数据移动终端接入Internet或其它分组数据网络的需求。     

基于GSM短消息的水情遥测终端通信系统设计

分析了目前在水情遥测终端(RTU)与中心站传输数据的几种通信方式的特点，介绍了GSM通信及其GSM短消息业务(SMS)。结合应用，设计了一种利用SMS进行数据传输的遥测终端通信系统，并给出了硬软件的实现方法。     

定位通终端的研究和设计

本文介绍了一种定位通信终端设备的设计和开发。首先介绍了基于ST20-GP7和STB5610套片的硬件系统的开发,然后介绍了基于实时内核STLite/OS20和ST的GPS软件库进行的软件系统的开发,同时介绍了GPS的NMEA-0183数据流格式以及进行GSM短信息服务的AT命令的用法。为GPS定位的应用开发提供了一个有价值的参考和范例。     

智能房间空调器通讯模组的设计与试验研究

设计一种适用于智能房间空调器的无线通讯模组。以STC系列单片机为模组的控制核心,可以处理对空调器的短信查询指令、短信控制指令和遥控控制指令,并能搜集空调器的运行状态信息,及时传输;用GSM模块完成模组的短信收发功能,通过RS485控制电路进行控制指令和数据的传送。通过移动控制设备对模组进行恶劣工况试验、极端电压试验、故障报警试验和远程操控试验,结果表明,模组达到日常使用要求,且安全、稳定、可靠,可以在空调器系统上广泛应用。     

ESAP: Efficient and secure authentication protocol for roaming user in mobile communication networks

The Global System for Mobile communication (GSM) network is proposed to mitigate the security problems and vulnerabilities observed in the mobile telecommunication system. However, the GSM network is vulnerable to different kinds of attacks such as redirection attack, impersonation attack and Man in-the Middle (MiTM) attack. The possibility of these attacks makes the wireless mobile system vulnerable to fraudulent access and eavesdropping. Different authentication protocols of GSM were proposed to overcome the drawbacks but many of them lead to network signalling overload and increases the call set-up time. In this paper, an efficient and secure authentication and key agreement protocol (ESAP-AKA) is proposed to overcome the flaws of existing authentication protocol for roaming users in the GSM network. The formal verification of the proposed protocol is presented by BAN logic and the security analysis is shown using the AVISPA tool. The security analysis shows that the proposed protocol avoids the different possible attacks on the communication network. The performance analysis based on the fluid flow mobility model shows that the proposed protocol reduces the communication overhead of the network by reducing a number of messages. On an average, the protocol reduces 60% of network signalling congestion overhead as compared with other existing GSM-AKA protocols. Moreover, the protocol not only removes the drawbacks of existing protocols but also accomplishes the needs of roaming users.     

电梯能效实时记录仪及系统研制

针对目前电梯能效监测方法繁杂、工作效率低及在模拟工况下不能完全反映电梯能效等问题,研制一套可在电梯实际运行工况下实时监测电梯能效记录仪及系统。该系统采用电力仪表与电流互感器测量电梯电参数,利用霍尔开关传感器测量电梯运动参数,基于双核ARM架构,应用有限状态机方法设计人机交互系统,选用SD卡存储实时能效数据;结合GSM模块,实现电梯能效信息短信查询、系统故障报警功能。测试结果表明:系统工作稳定,各项指标到达设计要求,具有推广价值。     

Social media-based systems: an emerging area of information systems research and practice

This article presents a review of the social media-based systems; an emerging area of information system research, design, and practice shaped by social media phenomenon. Social media-based system (SMS) is the application of a wider range of social software and social media phenomenon in organizational and non-organization context to facilitate every day interactions. To characterize SMS, a total of 274 articles (published during 2003–2011) were analyzed that were classified as computer science information system related in the Web of Science data base and had at least one social media phenomenon related keyword—social media; social network analysis; social network; social network site; and social network system. As a result, we found four main research streams in SMS research dealing with: (1) organizational aspect of SMS, (2) non-organizational aspect of SMS, (3) technical aspect of SMS, and (4) social as a tool. The results indicates that SMS research is fragmented and has not yet found way into the core IS journals, however, it is diverse and interdisciplinary in nature. We also proposed that unlike the conventional and socio-technical IS where information is bureaucratic, formal, bounded within the intranet, and tightly controlled by organizations; in the SMS context, information is social, informal, boundary-less (i.e. boundary is within the internet), has less control, and more sharing of information may lead to higher value/impact.     

Deriving origin destination data from a mobile phone network

Acquiring high-quality origin-destination (OD) information for traffic in a geographic area is both time consuming and expensive while using conventional methods such as household surveys or roadside monitoring. These methods generally present only a snapshot of traffic situation at a certain point in time, and they are updated in time intervals of up to several years. A technique was developed that makes use of the global system for mobile communications (GSM) mobile phone network. Instead of monitoring the flow of vehicles in a transportation network, the flow of mobile phones in a cell-phone network is measured and correlated to traffic flow. This methodology is based on the fact that a mobile phone moving on a specific route always tends to change the base station nearly at the same position. For a first pilot study, a GSM network simulator has been designed, where network data can be simulated, which is then extracted from the phone network, correlated, processed mathematically and converted into an OD matrix. Primary results show that the method has great potential, and the results inferred are much more cost-effective than those generated with traditional techniques. This is due to the fact that no change has to be made in the GSM network, because the information that is needed can readily be extracted from the base station database, that is the entire infrastructure needed is already in place     

Performance evaluation of shortest multipath source routing scheme

Multipath routing in mobile ad-hoc networks allows the establishment of multiple paths for routing between a source-destination pair. It exploits the resource redundancy and diversity in the underlying network to provide benefits such as fault tolerance, load balancing, bandwidth aggregation and the improvement in quality-of-service metrics such as delay. Previous work shows that on-demand multipath routing schemes achieve better performance under certain scenarios with respect to a number of key performance metrics when compared with traditional single-path routing mechanisms. A multipath routing scheme, referred to as shortest multipath source (SMS) routing based on dynamic source routing (DSR) is proposed here. The mechanism has two novel aspects compared with other on-demand multipath routing schemes: it achieves shorter multiple partial-disjoint paths and allows more rapid recovery from route breaks. The performance differentials are investigated using NS-2 under conditions of varying mobility, offered load and network size. Results reveal that SMS provides a better solution than existing source-based approaches in a truly mobile ad-hoc environment.     

A matrix-form GSM–CFD solver for incompressible fluids and its application to hemodynamics

A GSM–CFD solver for incompressible flows is developed based on the gradient smoothing method (GSM). A matrix-form algorithm and corresponding data structure for GSM are devised to efficiently approximate the spatial gradients of field variables using the gradient smoothing operation. The calculated gradient values on various test fields show that the proposed GSM is capable of exactly reproducing linear field and of second order accuracy on all kinds of meshes. It is found that the GSM is much more robust to mesh deformation and therefore more suitable for problems with complicated geometries. Integrated with the artificial compressibility approach, the GSM is extended to solve the incompressible flows. As an example, the flow simulation of carotid bifurcation is carried out to show the effectiveness of the proposed GSM–CFD solver. The blood is modeled as incompressible Newtonian fluid and the vessel is treated as rigid wall in this paper.     

Optimising installation (R,Q) policies in distribution networks with stochastic lead times: a comparative analysis of guaranteed- and stochastic service models

This paper studies two modelling approaches to the multi-echelon inventory optimisation problem in a distribution network with stochastic demands and lead times. It compares the performance of a novel guaranteed-service model (GSM), using an installation (R, Q) inventory control policy, with a stochastic service model (SSM) considering ordering, holding and flexibility costs. From both cycle service level and fill rate perspectives, our numerical analysis of the 1-warehouse 2-retailer network shows that cost difference between both models is driven by the internal service level at the warehouse. The GSM outperforms the SSM for over 80% of the simulated instances and realises an average total cost improvement of approximately 10%. This analysis goes against earlier results that showed a relatively low-cost difference between the two approaches, and demonstrates that it is worthwhile to evaluate competing models for multi-echelon inventory optimisation in real-world supply chains with batch ordering and variable lead times.