MIMO系统中基于SLNR的用户调度准则

多用户MIMO系统中,基于SLNR（signal-to-leakage-and-noise,信漏噪比）的预编码方案能够同时考虑噪声和信号泄漏问题,不但提高了系统性能,同时降低了系统的复杂度,但要求基站同时服务的数据流数之和不得大于其发射天线数. 因此,当用户数较多时,需要进行用户调度. 基于SLNR的用户调度准则只需要知道其他用户的信道信息,并能够合理的选择用户,通过仿真得知,该调度准则能够使系统获得良好的性能.     

一种新的基于层次的可信电子服务体系模型研究

针对目前电子服务可信性研究相对独立且缺少系统、明确的体系结构, 提出了一种新的基于层次的可信电子服务体系模型（layer-based model of trusted e-service, LMTS）, 定义了电子服务的可信性和模型中相邻层次间的接口, 设计了一种基于LMTS的电子服务请求安全协议, 在此基础上探讨了基于LMTS的可信电子服务信任评估机制。分析表明, 该模型具有可信性, 提高了服务信息的可信度。     

基于角色和信誉的跨域信任管理模型研究

目前,基于角色的信任管理及基于信誉的信任管理模型都存在安全缺陷。本文将基于角色的信任管理和基于信誉的信任管理相结合,提出了一种改进的信任管理模型,以提高跨域系统的安全性。     

Puzzle: A mobile application development environment using a jigsaw metaphor

ObjectiveCreate a visual mobile end user development framework, named Puzzle, which allows end users without IT background to create, modify and execute applications, and provides support for interaction with smart things, phone functions and web services.MethodsDesign of an intuitive visual metaphor and associated interaction techniques for supporting end user development in mobile devices with iterative empirical validation.ResultsOur results show that the jigsaw is an intuitive metaphor for development in a mobile environment and our interaction techniques required a limited cognitive effort to use and learn the framework. Integration of different modalities and usage of smart things was relevant for users.ConclusionPuzzle has addressed the main objective. The framework further contributes to the research on mobile end user development in order to create an incentive for users to go beyond consuming content and applications to start creating their own applications.PracticeUsage of a mobile end user development environment has the potential to create a shift from the conventional few-to-many distribution model of software to a many-to-many distribution model. Users will be able to create applications that fit their requirements and share their achievements with peers.ImplicationsThis study has indicated that the Puzzle visual environment has the potential to enable users to easily create applications and stimulate exploration of innovative scenarios through smartphones.     

Towards a trust,reputation and recommendation meta model

New trust, reputation and recommendation (TRR) models are continuously proposed. However, the existing models lack shared bases and goals. For this reason, in this work we define an innovative meta model to facilitate the definition and standardization of a generic TRR model. Following the meta model, researchers in the field will be able to define standard models, compare them with other models and reuse parts of them. A standardization is also needed to determine which properties should be present in a TRR model.In accordance with the objectives we were seeking, following our meta model, we have defined a pre-standardized TRR model for e-commerce, identified the fundamental concepts and the main features that contribute to form trust and reputation in that domain, respected the dependence on the context/role of trust and reputation, aggregated only homogeneous trust information; listed and shown how to defend from the main malicious attacks.     

Sharing your view: A distributed user interface approach for reviewing emergency plans

Emergency planning is an ongoing activity in which a multidisciplinary group of experts intermittently collaborate to define the most appropriate response to risks. One of the most important tasks of emergency planning is the review of plans as a way of maintaining, refining, and improving them. This review of plans is based on exchanging knowledge and experiences in order to take into account different perspectives and generate alternative solutions. An exploratory case study carried out within municipal organizations has disclosed how the application of rigid plan reviewing practices hinders team creativity and, consequently, effective decision-making. This paper presents a computer-based collaborative environment aimed at supporting unstructured team discussion during the post-hoc review of emergency plan. This collaborative environment allows emergency planning team members to share their view in a free manner by interacting with user interface components distributed across several input and output dimensions. The usage of the environment has proved how the application of new interactive technologies can create more dynamic work settings, fostering team creativity.     

潜在网络购物者与有经验者购买意愿比较研究*

感知风险和信任缺失被认为是阻碍网络购物发展的主要因素。以技术接受模型为理论基础,将感知风险和信任引入模型,把消费者分为潜在网络购物者和有经验网络购物者两大类,采用结构方程模型方法对影响我国消费者网络购物意愿的因素进行实证对比研究。实证结果表明：消费者感知网络购物有用性对其购买意愿的影响路径系数高于信任和风险因子对购买意愿的路径系数;感知风险对网络购买意愿有直接的负向影响;对于潜在消费者群体,信任显著影响其网络购物意愿,但对有购物经验的消费者群体信任却对网络购买意愿没有显著影响。     

基于加权语义网和有效信息的个性化用户兴趣建模*

为了提高个性化用户兴趣建模的准确率,对用户建模过程进行了优化。在计算文档相似度时,综合考虑特征词的语义关系以及在文档中的分布情况,引入加权语义网,提高了文档相似度计算精度;在计算兴趣度权值时,引入有效信息的概念及量化方法,以解决用户兴趣类权值计算过于主观的问题,并提出具体权值算法,提高了权值计算的准确性。实验结果表明,改进的方法在用户兴趣聚类和兴趣类别权值计算的准确率上都较以往方法有较大提高。     

分层可信计算平台模型的研究与实现*

提出了一种基于现有计算机网络的可信计算平台模型。该模型充分利用了现有的计算机及其网络平台的通用性,将现有的计算平台分层逻辑化为不同的信任层,不仅降低了可信计算平台模型实施的难度,而且提高了其灵活性、扩展性和效率;同时该模型从客户端系统的引导阶段出发构建完整的可信链,保证了可信计算平台的安全性;此外该模型解决了现有的可信计算平台的方向性和系统输入未知性的问题。原型系统实现的结果表明,由于系统中所有计算机及其网络构成统一的可信计算平台,使信任的传递从用户到用户,进而实现真正的对于用户体验的可信计算。     

城市交通弱势群体事故原因分析及事故烈度模型

以北京城市中心区为例,研究了城市交通弱势群体事故发生原因,结合交通弱势群体事故的特点及事故机理分析,提出了动态视线障碍的概念.依据交通弱势群体事故发生频率与严重程度,提出了事故烈度的概念和冲突烈度指标,通过数据分析,建立区域事故烈度与交通流量、车速之间的函数关系,以便更好地预测和评价交通弱势群体的交通安全形势状况.