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1.
In the Internet or cloud computing environments, service providers provide more and more content services. Users can use these convenient content services in daily life. The major data of the user are maintained by the service providers except that some personal privacy data are stored at the client device. An attacker may try to invade the systems, and it will cause the damage of users and service providers. Also, users may lose their mobile devices and then it may cause the data disclosure problem. As a result, the data and privacy protection of users become an important issue in these environments. Besides, since many mobile devices are used in these environments, secure authentication and data protection methods must be efficient in these low resource environments. In this paper, we propose an efficient and privacy protection digital rights management (DRM) scheme that users can verify the valid service servers and the service servers can ensure the legal users. Since the key delegation center of the third party has the robust security protection, our proposed scheme stores the encrypted secret keys in the key delegation center. This approach not only can reduce the storage space of the user devices, but also can recover the encrypted secret keys in the key delegation center when a user loses her/his devices for solving the device losing problem.  相似文献   

2.
In this paper, a novel approach for service substitutions based on the service type in terms of its interface type and behavior semantics is proposed. In order to analyze and verify behavior-consistent service substitutions in dynamic environments, we first present a formal language to describe services from control-flow perspective, then introduce a type and effect system to infer conservative approximations of all possible behaviors of these services. The service behaviors are represented by concurrent behavior expressions (CBEs). Built upon the interpretation of CBEs, behavior-consistent service substitutions are defined and analyzed by subtyping technology. The correctness of the analysis approach is guaranteed by type safety theorem, which is mechanically proved in the Coq proof assistant. Finally, applications in web services show that our method is effective and feasible.  相似文献   

3.
Uncertainty design can take account of aleatory and epistemic uncertainty in optimal processes.Aleatory uncertainty and epistemic uncertainty can be expressed as evidence theory uniformly, and evidence theory is used to describe the uncertainty. Transferring and response with evidence theory for structural optimal design are introduced. The principle of response evaluation is also set up. Finally, the cantilever beam in a test system is optimized in the introduced optimization process, and the results are estimated by the evaluation principle. The optimal process is validated after the optimization of beam.  相似文献   

4.
CT colonography (CTC) is a non-invasive screening technique for the detection of eolorectal polyps, as an alternative to optical colonoscopy in clinical practice. Computer-aided detection (CAD) for CTC refers to a scheme which automatically detects colorectal polyps and masses in CT images of the colon. It has the potential to increase radiologists' detection performance and greatly shorten the detection time. Over the years, technical developments have advanced CAD for CTC substantially. In this paper, key techniques used in CAD for polyp detection are reviewed. Illustrations about the performance of existing CAD schemes show their relatively high sensitivity and low false positive rate. However, these CAD schemes are still suffering from technical or clinical problems. Some existing challenges faced by CAD are also pointed out at the end of this paper.  相似文献   

5.
Fault management is crucial to provide quality of service grantees for the future networks, and fault identification is an essential part of it. A novel fault identification algorithm is proposed in this paper, which focuses on the anomaly detection of network traffic. Since the fault identification has been achieved using statistical information in management information base, the algorithm is compatible with the existing simple network management protocol framework. The network traffic time series is verified to be non-stationary. By fitting the adaptive autoregressive model, the series is transformed into a multidimensional vector. The training samples and identifiers are acquired from the network simulation. A k-nearest neighbor classifier identifies the system faults after being trained. The experiment results are consistent with the given fault scenarios, Which prove the accuracy of the algorithm. The identification errors are discussed to illustrate that the novel fault identification algorithm is adaptive in the fault scenarios with network traffic change.  相似文献   

6.
A new approach,mass injection near the slat cusp,is proposed for the suppression of slat noise.The mechanism and efciency of the slat noise suppression using upstream mass injection are numerically studied with hybrid Reynolds-averaged Navier-Stokes simulation/Large eddy simulation(RANS/LES)of a three-component high-lift model.Ffowcs-Williams and Hawking(FW-H)integration is employed to obtain far-field acoustic characteristics.Results show that with injection,aerodynamic capability of the high-lift devices is sustained.In addition,a considerable noise reduction is observed in the downward direction.With detailed analysis of the time-averaged and instantaneous flow fields,two mechanisms are identified as the reason accounting for the noise suppression:upstream mass injection significantly reduces the scale and strength of the vortices stemming from the cusp;the shear layer is lifted up,which relieves the shear layer impingement on the slat lower surface.  相似文献   

7.
Growing numbers of users and many access control policies which involve many different resource attributes in service-oriented environments bring various problems in protecting resource.This paper analyzes the relationships of resource attributes to user attributes in all policies, and propose a general attribute and rule based role-based access control(GAR-RBAC) model to meet the security needs. The model can dynamically assign users to roles via rules to meet the need of growing numbers of users. These rules use different attribute expression and permission as a part of authorization constraints, and are defined by analyzing relations of resource attributes to user attributes in many access policies that are defined by the enterprise. The model is a general access control model, and can support many access control policies, and also can be used to wider application for service. The paper also describes how to use the GAR-RBAC model in Web service environments.  相似文献   

8.
This paper analyzes the drop transfer process in gas metal arc welding in short-circuit transfer mode (GMAW-S) in order to develop an optimized spatter rate model that can be used on line. According to thermodynamic characters and practical behavior, a complete arcing process is divided into three sub-processes: arc re-ignition, energy output and shorting preparation. Shorting process is then divided as drop spread, bridge sustention and bridge destabilization. Nine process variables and their distribution are analyzed based on welding experiments with high-speed photos and synchronous current and voltage signals. Method of variation coefficient is used to reflect process consistency and to design characteristic parameters. Partial least square regression (PLSR) is utilized to set up spatter rate model because of severe correlativity among the above characteristic parameters. PLSR is a new multivariate statistical analysis method, in which regression modeling, data simplification and relativity analysis are included in a single algorithm. Experiment results show that the regression equation based on PLSR is effective for on-line predicting spatter rate of its corresponding welding condition.  相似文献   

9.
Objective Due to the incompleteness and complexity of fault diagnosis for power transformers, a comprehensive rough-fuzzy scheme for solving fault diagnosis problems is presented. Fuzzy set theory is used both for representation of incipient faults' indications and producing a fuzzy granulation of the feature space. Rough set theory is used to obtain dependency rules that model indicative regions in the granulated feature space. The fuzzy membership functions corresponding to the indicative regions, modelled by rules, are stored as cases. Results Diagnostic conclusions are made using a similarity measure based on these membership functions. Each case involves only a reduced number of relevant features making this scheme suitable for fault diagnosis. Conclusion Superiority of this method in terms of classification accuracy and case generation is demonstrated.  相似文献   

10.
A new nonlinear variable structure excitation controller is proposed. Its design combines the differential geometry theory and the variable structure controlling theory. The mathematical model in the form of "an affme nonlinear system" is set up for the control of a large-scale power system. The static and dynamic performances of the nonlinear variable structure controller are simulated. The response of system with the controller proposed is compared to that of the nonlinear optimal controller when the system is subjected to a variety of disturbances. Simulation results show that the nonlinear variable structure excitation controller gives more satisfactorily static and dynamic performance and better robustness.  相似文献   

11.
下一代网络(NGN)是目前网络发展的趋势,是今后通信业务和互联网业务的核心,其核心承载将使用IPv6技术。作为IPv6内在组成部分的移动IPv6技术,对于下一代网络,尤其是对于下一代移动通信网络,有着极其重要的影响。通过移动IPv6技术,可以各种接入方式,将宽带、移动互联网和现有的无线系统等都无缝地集成到IP层,通过一种网络基础设施提供所有通信和信息服务,即是下一代网络发展的方向,也是移动IPv6的核心优势。  相似文献   

12.
针对云计算环境中用户如何有效的选择云服务商及签订服务协议的问题,本文提出一种基于服务等级协议SLA的中立第三方动态信任评估系统框架.通过在用户端和云端设置的监测代理,实时监控并采集SLA相关的实际服务数据;通过实际观测的参数、其变化情况及SLA协定的参数,同时结合用户主观评价,计算得到服务质量的信任值,最终形成对云服务商服务可信度的全面的和动态的评价.本文给出了系统框架结构、评估方法和评估输入与流程等信任评估的实现方法.与其他信任评估方法相比,本文提出的模型全面融合了多种数据主客观评价来源,给出了具体流程和方法,具有更好的客观性、准确性和可信性.  相似文献   

13.
随着传统交通运输业向现代交通运输业的转变,交通服务的范畴不断延伸和发展,这给交通行业的发展带来了挑战和机遇.交通行业应抓住机遇,迎接挑战,合理组织,深入研究,加快推进交通服务领域的标准化工作,扩大服务标准的覆盖范围,建立健全交通服务标准体系,为传统交通产业向现代服务业的转型提供强有力的标准化工作的支持.  相似文献   

14.
本文从分析高校教师服务学生的内涵及存在的问题入手,探讨高校教师服务学生的策略。高校教师应该树立服务学生的理念、掌握服务学生的有效途径、提高服务学生的能力;高校则应该通过激励机制激发教师服务学生的动机,调动教师服务学生的积极性,促使教师为学生提供高质量的服务。  相似文献   

15.
IntroductionThere are many strategies for Qo S service inbroadband telecommunication networks[1] . Withthe fast evolution of chip and software techniques,the telecommunication networks are running withmore and more throughputcapabilities and self- ad-ministration capabilities.On the other hand,theapplication of methodologies based on concepts ofartificial intelligence in the telecommunication fieldis being more and more frequently used[2 ] .Thispaper gives a new strategy to evaluate the Qo S…  相似文献   

16.
李少飞 《北方交通》2010,(3):122-124
依据现实路网整体结构中存在多种服务质量等级,一方面要满足不同类型的交通需求,另一方面要使路网交通高效率运行,以达到资源共享的最大化,建立了路径边际成本定价模型。  相似文献   

17.
深汕高速公路东段(以下简称深汕东),于1996年建成通车,经过近十年的运营,路面服务质量明显下降,为了保证区域交通网的正常服务功能,准备对该工程进行大修.文中根据现有路况,结合相关资料,分析了路面破损的主要原因,并进行大修施工图设计.  相似文献   

18.
提出并实现了一种基于IP多播的数字视频监控系统的网络系统.介绍了系统的网络设计要求,说明了该系统的设计思想-基于TCP/IP协议、客户-服务器模型、IP多播、WinSock2方式与流媒体通信相结合,实现实时图像传输和远程控制.  相似文献   

19.
汽车金融公司在我国发展的障碍及对策研究   总被引:1,自引:0,他引:1  
从汽车金融公司的概念和特征出发,通过法律上的规制、个人信用体系、人才资源、国内大型汽车公司设立汽车金融公司的意愿等方面分析汽车金融公司在我国发展的障碍,并针对障碍提出汽车金融公司应加强与商业银行和保险公司的合作,实施汽车金融服务人才培养与引进战略,银行和企业应构建资源共享的个人征信体系,大型汽车厂家应大力推进设立汽车金融公司的进程等对策。  相似文献   

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