基于CAS的单点登录系统应用研究

随着信息系统的迅速发展,各类信息化应用系统逐步建立,但是各应用系统之间自成体系,从而导致了每使用一个系统就要重新登录一次,给用户的使用和管理员的管理带来了很多不便.本文研究基于CAS的单点登录系统应用,很好地解决了使用和管理困难问题,介绍了基于CAS的单点登录系统应用设计研究,系统采用用户管理LDAP轻量级目录服务、CAS中央认证服务,设计了一个统一管理界面,通过Web服务传递用户参数,实现了多应用系统的整合.     

单点登录在企业信息门户系统中的研究与实现

随着企业信息化的高速发展,针对不同阶段的管理需求,企业实施了各种各样的信息化应用系统。但各应用系统的用户管理、系统登录自成体系,导致用户每使用一个系统都需要重新登录一次,给系统的使用和管理带来不便。用户需要一种更为便捷、高效的登录模式,单点登录就是为解决这个问题而提出的。在此以某企业信息门户系统的开发为实例,研究了单点登录的架构模型,基于Java语言,开发完成统一的信息门户界面,实现企业内部多个系统的一次性登录。     

基于改进的SAML单点登录系统设计与实现

单点登录(Single Sign-on,简称SSO)是一种用户只需登录一次就能够访问所有互相信任的系统。针对传统的单点登陆流程复杂、缺乏灵活性以及效率低的不足之处,提出了一种在SAML的基础上的单点登录的改进型模型,这个模型基本解决了用户跨域访问单点登录问题,具有很好的安全性和普适性。依据改进后基于SAML单点登录的模型,设计了符合SAML2.0规范的单点登录系统,系统采用模块化的思想,给出并实现了一个基于上述改进模型的单点登录系统。最后通过系统实例表明,该系统减少了验证用户声明的通信,提高了工作效率和系统的安全性,在电子商务、电子政务等多应用系统中具有非常好的应用前景。     

基于SSL VPN单点登录在区域卫生信息平台中的应用

单点登录是近年来在开发大平台信息系统中出现的一门新兴技术,文章结合作者在开发岳阳楼区基于健康档案的区域卫生信息平台的实践,提出了单点登录技术与SSL VPN技术相结合的基于SSL VPN单点登录技术,为整合多种医疗业务应用系统提供了一个统一身份认证、统一用户管理、统一授权管理、统一资源管理和单点登录平台.     

单点登录技术在军事信息系统中的应用研究

随着军队信息化工作的进行,越来越多的军事信息系统被开发出来,如何更好地管理各个系统的用户和权限已成为一个重要的研究课题.单点登录技术可以实现一次登录,访问所有授权的系统.在分析了军事信息系统的现状和现有单点登录技术的特点基础上,得出了适合于军事信息系统的单点登录技术.针对某军事信息系统,总结其单点登录需求,给出了总体方案和系统组成,设计了权限管理、用户身份映射等关键模块,并给出了具体实现方法.实践表明,单点登录技术的应用将会大大提高工作效率,促进信息化工作的进行.     

单点登录技术在Web应用中的研究与实现探究

一对多的框架关系组成是单点登录的明显特征,它是由单一的用户登录系统对多个应用服务进行的统一管理所提供的用户登录认证.这种统一化登录系统实现了Web应用的信息共享,在一个系统下的任何站点的用户,他都不必反复登录转换身份的去进行身份认证,不仅节省了时间,使得操作与开发效率提升,还减少了不必要的消耗,避免了重复开销,降低了操作成本.本文从实现单点登录的常见策略开始进行分析,从而优化单点登录技术在Web应用中的运用价值,确保在Web请求代理策略下简单的单点登录系统的实现,保证Web应用的高效运用,推动单点登录技术的良好发展.     

基于Java EE的单点登录技术研究与实现

文章针对多个应用系统的复杂登录问题,介绍了单点登录系统,并阐述了单点登录的几种模型分类,在此基础上重点介绍了基于Cookie机制的单点登录和基于SAML的单点登录.基于这两种实现方式,本文进行了单点登录系统设计与仿真实现,证明所实现的系统能够解决当前web应用系统面临的登录问题.     

铁路企业统一身份认证平台的设计与实现

针对铁路企业工作人员使用多个应用系统需要同时记忆多套用户账号信息的现状,文中基于铁路统一用户管理系统的用户数据,设计了一种铁路应用系统用户的统一身份认证系统。该系统采用单点登录、Token、Cookie、Session共享等技术,实现了用户信息与应用系统的分离、统一用户管理、统一认证、一处登录、处处共享等功能,从根本上解决了不同应用系统重复维护用户信息的问题,使用户能够更便捷地访问不同的应用系统,并保证了不同应用系统间用户信息的一致性、安全性和共享性。     

基于Web的校园网统一身份认证系统的实现

本文提出了一个基于．NETPassport认证机制的统一身份认证系统,本系统利用Windows2003系统自带的ActiveDirectory组件建立目录服务数据库和SQLServer数据库,实现用户信息、组织架构和角色的统一管理,利用．NETWebService技术实现用户单点登录,实现用户统一身份认证,为数字化校园建设提供了技术参考。     

一种基于证书的登录控制实现

实施建立一套较好的登录控制机制,能够为用户提供统一的信息资源认证访问入口,建立统一的、基于角色和个性化的信息访问、集成平台。通过实施单点登录功能,使用户只需一次登录就可以根据相关的规则去访问不同的应用系统,提高信息系统的易用性、安全性、稳定性,并在此基础上进一步实现政府、企业用户高速协同办公。     

基于情景感知的低交互移动双因素认证系统

针对传统双因素认证缺乏可用性的问题,本文提出了一种基于情景感知的低交互移动双因素认证系统.用户通过本系统登录网站时,除输入用户名和口令外,只需点击令牌程序的认证键即可完成认证,平均登录时间不超过5秒.同其它可用性加强的移动双因素认证系统相比,本系统能够抵抗同一环境下的攻击者,而且支持用户手机浏览器进行网站登录.最终安全分析和实验结果证实了本方法的有效性.     

The effect of system-initiated advice on the use of menu navigationshortcuts

It is noted that computer users often do not take advantage of system shortcuts; instead they rely on familiar but less efficient methods for getting their work done. The authors examine a system that incorporates system-initiated online help to advise users of shortcuts for menu navigation. Subjects received either no advice messages or one of three advice message types, varying in timing and specificity, and subjects were assessed on their subsequent use of shortcuts. Results revealed that users who receive system-initiated advice take greater advantage of shortcuts and are able to complete their work more quickly than users who receive no system-initiated advice messages. Further, a majority of users reacted positively to the messages, finding them helpful in introducing shortcuts     

智能IPTV运营决策系统方案设计与探讨

智能IPTV运营决策系统构建集成播控平台和用户之间的数据闭环,实现平台智能化、精细化和个性化内容运营,打造更加适合IPTV用户的优质产品,为用户提供更好的视听服务。在发展新用户的同时,进一步提升存量用户的ARPU值,推动IPTV业务持续发展。     

多载波多用户下行NOMA系统的资源分配算法

非正交多址接入技术作为5G的候选技术之一受到了广泛关注。研究了以系统吞吐量优化为目标的多载波多用户NOMA系统下行链路的资源分配问题。在该问题的求解中,为了提高系统的吞吐量,子载波间采用线性注水算法,叠加用户间采用分数阶功率分配算法。同时,考虑了远近用户数目不等场景下能够调度更多的用户,在NOMA传输方案设计中引入时分的概念,将整个时间段t分为两个时隙,在不同时隙内实现不同远近用户分组的动态配对方案,从而在保证用户公平性的基础上,充分利用子信道资源,实现系统吞吐量的优化。仿真结果表明,对比于传统NOMA和OFDMA,提出的方法可以在相同的发射功率情况下传输更多的比特数。     

Congestion relief on power-controlled CDMA networks

A digital cellular radio code-division multiple-access (CDMA) system can only support a finite number of users before the interference plus noise power density, I₀, received at the cellular base station causes an unacceptable frame-error rate. Once the maximum interference level is reached, new arrivals should be blocked. In a power-controlled CDMA system, the base station can direct mobiles to reduce their power and data rate to reduce interference and allow more users on the system. This approach is employed in TIA IS-95 with respect to the time-varying voice activity on cellular voice channels. We investigate an alternative technique where we adjust the power and data rate of mobile data users to the time-varying interference level to allow more users on a congested system. This scheme was simulated for various proportions of voice and data users and offered traffic levels. Blocking probabilities are reduced in some cases by two orders of magnitude. Message wait time, now a random variable, may exceed the wait time for a constant rate system at high traffic levels. If the cellular carrier has a maximum blocking requirement, an adaptive rate/power system can increase the capacity. For example, a base station that normally supports 26.4 Erlangs offered traffic with 2% blocking can support 33.5 Erlangs with the same blocking probability if adaptive rates and power control are used. Thus, the adaptive rate system can increase the capacity by 27%     

A joint performance measure for the decorrelating multiuser detector

We analyze the performance of the decorrelating multiuser detector for a wireless communication system. Instead of looking at the error probability for each user, we focus on the probability distribution of the number of correctly decoded users at the receiver and the average number of correctly decoded users under the conditions of equicorrelated signatures and perfect power control. The approach is motivated by the fact that the error events for different users are not independent. Numerical results show that when the number of users is large, instead of using a set of long signatures with a very low negative cross-correlation, we can use a set of shorter signatures with a reasonably high positive correlation without sacrificing the performance. It is also found that the average number of correctly decoded users increases with increase in signal-to-noise ratio and decreases when the cross-correlation between users becomes more negative or more positive.     

Web应用中帮助功能的设计与实现

“帮助”是所有软件系统的重要功能。人们试图用各种各样的方法向用户提供帮助．以便使系统的学习和使用更加简单和方便。对于一些复杂的应用系统，特别是那些依赖于用户经验的系统。用户的经验知识能够为其他用户提供更有价值的帮助。在Web网络环境中，网络使得用户之间的互相帮助成为可能。文章分析了各种各样的帮助功能，以及帮助的实现过程。给出了Web环境中一种新颖的基于用户和计算机协作的智能帮助模型，最后在一个E-learning系统中进行了实验。     

Multi-Antenna Downlink Channels with Limited Feedback and User Selection

We analyze the sum-rate performance of a multi- antenna downlink system carrying more users than transmit antennas, with partial channel knowledge at the transmitter due to finite rate feedback. In order to exploit multiuser diversity, we show that the transmitter must have, in addition to directional information, information regarding the quality of each channel. Such information should reflect both the channel magnitude and the quantization error. Expressions for the SINR distribution and the sum-rate are derived, and tradeoffs between the number of feedback bits, the number of users, and the SNR are observed. In particular, for a target performance, having more users reduces feedback load.     

Massive MIMO Systems for 5G Communications

Massive MIMO will improve the performance of future 5G systems in terms of data rate and spectral efficiency, while accommodating a large number of users. Furthermore, it allows for 3D beamforming in order to provide more degrees of freedom and increase the number of high-throughput users. Massive MIMO is expected to provide more advantages compared to other solutions in terms of energy and spectral efficiency. This will be achieved by focusing the radiation towards the direction of the intended users, thus implementing simultaneous transmission to many users while keeping interference low. It can boost the capacity compared to a conventional antenna solution, resulting in a spectral efficiency up to 50 times greater than that provided by actual 4G technology. However, to take full advantage of this technology and to overcome the challenges of implementation in a real environment, a complicated radio system is required. The purpose of this work is to present the MIMO technology evolution and challenges in a simple introductory way and investigate potential system enhancements.

     

Coding for a Multiple-Access Frequency-Hopping System

A multiuser system employing on-off FSK modulation in conjunction with frequency hopping is examined for digital transmission. The receiver consists of a bank of bandpass noncoherent detectors followed by a message decoder. An analysis is presented for a transmission channel characterized by Rayleigh fading and additive Gaussian noise. The main source of impairment is interference between users. An upper limit on the number of simultaneous system users for acceptable transmission quality is derived. An example of a system with (one-way) bandwidth of 20 MHz and transmission rate of 32 kbits/s per user shows a maximum of 169 users at an average SNR on the channel of 25 dB and a bit error probability not exceeding 10^-3. The effect of applying error correcting codes to the system is evaluated. It is shown how Reed-Solomon codes can be used to generate both user identification and message coding. Such coding increases the number of users the system can accommodate in the example above to 212. Convolutional codes are shown to be even more effective. Such a code of constraint length 2 results in 285 simultaneous users in the example, which is an increase of 70 percent over an uncoded system. The drawback of coding is an increased complexity of the receiver. The amount of computation needed for the decoding of block and convolutional codes is estimated.