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1.
A method of constructing GPS-based positioning services system by means of JAVA technology is introduced in this paper. The position data, which are sent from GPS satellites, are received by GPS receiving terminal and are analyzed by mobile computing client developed on J2ME in accordance with the differential GPS algorithm. The client submits special position querying information to position server in way of wireless GPRS network. After computing and data querying, the server developed by J2EE returns results to the mobile device. Then, the mobile computing client displays the position map or carries out further processing. All of these form a highly precise location-based services system. 相似文献
2.
With the rapid development of wireless network and mobile computing,the security of network becomes more important.As one of wireless mobile network,mobile Ad hoc network has new vulnerabilities that do not exist in a fixed wired network,and is susceptible to attacks.This paper introduces some methods which used in intrusion detection system and provides a new model of system based on multi-layer integrated distributed technology,especially recommend the protocol analyzing method in this system. 相似文献
3.
为满足农村基层低成本、个性化、快速测土配肥的需求,解决现有的通用浸提剂在基层或流动服务条件下不能用于速效氮的测定的问题,研究了中性、石灰性土壤中的主要营养元素氮磷钾的联合浸提。为便于应用现有的测土施肥技术体系,基于土壤化学的原理,运用相关性的分析方法,本研究提出了以碳酸氢钠、硫酸钠为基础的土壤有效氮磷钾联合浸提剂。结果表明,使用该浸提剂,可缩短土壤氮磷钾养分的提取时间2/3以上,且速测数据与常规浸提分析数据的相关性达到了极显著水平(a=0.01),在迅捷牌土肥速测仪上应用它测试土壤氮磷钾,测试成本降低10倍以上,达到了个性化测土施肥的成本低、速度快的要求,适宜在基层或流动服务车上进行测土施肥时应用。 相似文献
4.
The mobile IPv6 protocol solves the mobile communication problems in the next generation Internet.The mobile IPv6 not only provides huge address space,but also strengthens handover ability of mobile user,and realizes route optimization.IPv6 will become the next generation Internet protocol;so the mobile IPv6 will be widely used in the next generation Internet.The moblile IPv6 will provide in the future network,a uniform transmission platform that transmits data,voice data and video data,or other services.People not only put forward more and more requirements for multimedia playing operation,but also bring forward higher request,which is interaction capabiliby communication,Because the long latency associated with mobile IPv6's return routability procedure of correspondent node binding,this paper presents a fast correspondent node binding of method based on early binding updates option.The method not only eliminates at least 50% of the additional delay that a standard correspondent node binding adds to the network stack's latency,but also reinforces the ability to support alternant real-time application. 相似文献
5.
Intrusion detection system is an essential component of network security protection mechanisms. Most intrusion detection system can not adapt the variation of network environment. Aiming at this problem, an adaptive strategy that composed of condition space and strategy space is proposed. The condition space describes the network environment and the strategy space describes the strategy. There is an exclusive strategy corresponds to a certain environment state in condition space. On the base of the adaptive strategy, an adaptive intrusion detection system based on agent and data mining is designed. The simulation experiments indicate that the adaptive strategy is effective. 相似文献
6.
Mobile phones,gender‐based violence,and distrust in state services: Case studies from Solomon Islands and Papua New Guinea 
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下载免费PDF全文 Stephanie Ketterer Hobbis 《Asia Pacific viewpoint》2018,59(1):60-73
This paper examines the potential benefits and pitfalls of mobile phones for accessing social services, particularly in response to gender‐based violence, in Solomon Islands and Papua New Guinea. Drawing on 13 months of ethnographic field research, I show how mobile phones increase rather than decrease perceived distances between social service providers and those they intend to serve. Mobile phones exaggerate the visibility of the shortcomings of the Solomon Islands and Papua New Guinea states and solidify an already entrenched distrust in the state and state services. This distrust is accentuated in experiences with mobile phone‐based mediations of gender‐based violence. Despite the positive influences of mobile phones, they are also recognised as conduits of violence. As such, mobile phones are not only morally ambivalent technologies but also, at times, actively disliked and their use discouraged. This challenges the optimism that surrounds many information and communication technologies for development (ICT4D) projects. When assessing the potentials, successes, and failures of ICT4D programmes, there is a need to pay more attention to the consequences of ‘negative’ or ‘unreliable’ usages of mobile phones as relational technologies. 相似文献
7.
Theo Notteboom 《Asia Pacific viewpoint》2007,48(3):330-343
Abstract: Container ports located in a delta of navigable waterways generally strive to develop the inland river services as a competitive transport mode, with a view to serving local and distant hinterland regions. The spatial and functional development of river‐based container networks is location‐specific and time‐specific. While each barging network and associated seaport system has its own dynamics, similarities in development patterns cannot be excluded. This paper discusses similarities and dissimilarities between the spatial and the functional development of the container river service networks of the Yangtze River and the Rhine River. It is shown that the Yangtze service network has the tendency to converge, in more than one aspect, with the (historical) development pattern of inland container services in the Rhine basin. 相似文献
8.
《保鲜与加工》2000,(2):20-22
The bi-directional Hybrid Fiber/Coaxial (HFC), which has almost 1GHz frequency bandwidth to transmit information, is the best access mode except Fiber to the Home (FTTH). Initial experiences indicate that real-world HFC networks are susceptible to a variety of radio-frequency impairments that significantly reduce the benefits of using high-speed cable modems. In this paper, the performance of data services in the TCP sub-layer of a HFC network is discussed and an agent server is used to enhance the performance of remote data transmission.[WT5HZ] 相似文献
9.
ABSTRACT With the passage of the Telecommunications Act of 1996, Congress directed the Federal Communications Commission and all fifty U.S. states to encourage the deployment of advanced telecommunication capability in a reasonable and timely manner. Today, with the rollout of advanced data services such as digital subscriber lines (xDSL), cable modems, and fixed wireless technologies, broadband has become an important component of telecommunication service and competition. Unfortunately, the deployment of last‐mile infrastructure enabling high‐speed access has proceeded more slowly than anticipated and competition in many areas is relatively sparse. More importantly, there are significant differences in the availability of broadband services between urban and rural areas. This paper explores aspects of broadband access as a function of market demand and provider competition. Data collected from the Federal Communications Commission is analyzed using a geographic information system and spatial statistical techniques. Results suggest significant spatial variation in broadband Internet access as a function of provider competition in the United States. 相似文献
10.
无线移动自组网是仅由移动节点所组成的网络,具有分布式控制、自组织、多跳等特点,由于该网络具有抗毁性能高、易铺设等性质,越来越受到业界的广泛关注。原始的路由协议已经满足不了现有网络不可预测、频繁变化的拓扑结构的需要,因此,在之前研究的基础上,对现有Ad Hoc网络AODV路由协议进行了研究,并设计出一种基于AODV协议的改进路由协议——基于认知的AODV协议(Cognitive-based AODV,CAODV)。通过NS2进行试验仿真,结果表明,CAODV协议具有比AODV协议更加优良的性质,可以有效降低重启路由发现频率,增加断裂链路的修复成功率,降低协议的控制负载,对现有网络的动态变化具有很强的适应能力。 相似文献
11.
Wang Tingkai Qin Ansong Huang Saninan 《保鲜与加工》1992,(5):89-95
This paper presents a new method of self tuning adaptive control which adopts a neural network to identify the characteristics of a second order nonlinear system, which is in turn applied to adaptive control. The simulations show that the method has good capability of sduty and adaptation. 相似文献
12.
[目的]准确及时的农情信息是各级政府制定农业政策、管理指导农业生产的重要依据。遥感技术在山东省农业资源调查、农情监测、灾害预警等领域发挥着越来越重要的作用,亟需建立一个服务于农业生产管理需求的省级农情遥感监测业务化运行平台。[方法]利用地理信息系统（GIS）、遥感技术(RS)和网络技术,基于MapGIS平台,提出了山东省农情遥感监测平台建设的重要意义、设计原则、总体架构、建设内容以及系统的总体部署。[结果]平台的建立,将实现山东省主要粮食作物面积、长势、产量、灾害等农情信息的动态监测与及时发布,同时为公众提供专题遥感监测产品服务。[结论]推动农情遥感监测的广泛应用和产业化发展,为保障粮食安全、强化农业生产科学管理和建设现代农业提供强大的支撑。 相似文献
13.
北方果树霜冻害远程监控与报警系统初步研究与实现 总被引：1，自引：1，他引：0
为提高北方果树防霜冻害管理水平,基于物联网架构,设计实现了北方果树霜冻害监测与报警系统。该系统结合实时获取果树生长环境数据,及果树霜冻害发生规律和专家知识库,为用户提供远程果树环境信息分析和霜冻害智能诊断服务。同时为满足不同生产条件需求,结合用户需求和环境状况,提供自动报警。根据用户随时随地获取信息的需求,基于多种网络技术等(如Internet、android等移动互联网),开发了可用于PC终端、移动终端(如智能手机、平板电脑等)多平台管理模式。通过提供现场综合远程实时监控、数据采集、网络传输、数据管理分析及报警预警等功能,系统实现了对果树生长的全方位多功能的远程监控与综合管理,有效提高了果树防霜冻害监控管理水平。 相似文献
14.
Engineering designed mode has entered a new stage because of the development of network. New calculating system based on network appeared. By analyzing the common B/S architecture, this paper brings forward an reformative architecture based on Web services and ASP. NET in order to build the new mode of engineering calculation. It can fully implement the sharing of the resources and provide the engineering designers a wonderful calculating environment, and the working eifficiency of designers can be enhanced. 相似文献
15.
It is an important way for co production efficiency improvement and system robustness to deeply understand the relationship between the structure and function of interfirm collaborative production networks (ICPN) . This paper develops the topological model for ICPN based on the analysis of the characteristics of interfirm collaborative production modes. By introducing complex networks, a case of Polyurethane industry is simulated. The results show that ICPN has the characteristics of small world, scale free and centralities of nodes. Moreover, complex network characteristics affect the capability and efficiency of production system. 相似文献
16.
Natural monopoly is characterized by economies of scale and production cost subadditivity in the traditional and new theory of natural monopoly.The paper thinks that they are incorrect in the method of judging some industry as natural monopoly.They neglect some important transaction(system) cost factors.Once giving up the old analytic framework, the authors find that economies of scale and production cost subadditivity are neither necessary nor sufficient for natural monopoly.Based on the analysis on weaknesses of the traditional and new theory of natural monopoly,the paper discusses the essential character of natural monopoly and educes some corresponding revelations about the reform of network industries. 相似文献
17.
This paper concludes the technique and application character of USSD, the related network structure of USSD platform, explains the handle flow of the interactive response of USSD. By analyzing the application type in mobile communication and market benefit of USSD, combining the feature of USSD service platform, it presents the infrastructure of USSD system and application, including composing of core system, deployment of application (assignment of service code, suitable application type and market benefit), and the influence and change to the existent network. 相似文献
18.
基于数字图书馆的农业移动信息服务集成模式研究 总被引：1，自引：1，他引：0
本研究主要介绍了移动数字图书馆的概念、特点及服务三农的新模式,提出建设云南农业数字图书馆,全面进行数字资源建设整合;完善“三农通专家咨询服务平台”服务功能模式,深入科普基地全面进行需求分析;研究移动信息服务集成的相关理论,构建完善的理论体系;构建适合云南本地特色的移动信息服务新模式四方面研究云南农业信息移动服务集成模式,同时对移动农业信息服务面临的问题进行了讨论。 相似文献
19.
Along with the widely using of mobile telephone, the SMS (Short Message Service) has achieved more and more approbation of consumers. Besides the point-point application of SMS among mobile phones, a new application of SMS between information system and mobile phones is developed quickly now, and it is a new way to achieve information conveniently and duly for users. In this paper, we design a software based on SMS to solve some problems which exists in the communication among employees. We also give out the system's functions, key technology and application in the enterprises. This system has some important value in theory and application for building a digital enterprise. 相似文献
20.
In CDMA communication system, the relativities between users result in Multiple Access Interference (MAI). With the increase of users, MAI becomes the main jam of broadband CDMA communication system. Multi-User Detection (MUD) is the most important technology of anti-jamming in the broadband CDMA communication system, which can eliminates MAI effectively by using the information of all user signals to detection single. This paper analyze the expression of system capability without MUD and with MUD, and puts forward the way to increase system capability by using MUD. Then the influence of MUD on CDMA system capability is discussed by MATLAB emulation. Basing analysis and emulation, the conclusion is got: the higher the MUD efficiency, the better the improvement of CDMA system capability; under the same MUD efficiency, the lower data rate, the smaller inter-cell interference, the lower the ratio of bit energy to power spectrum, the better the improvement of CDMA system capability. 相似文献