基于角色的访问控制中职责分离的设计与实现

职责分离是基于角色的访问控制技术中保障实现最小特权原理的关键因素。基于实际项目开发经验,详细阐述了基于角色的访问控制技术中职责分离实现的目的、原理、实现逻辑以及具体的实现方法。     

基于角色的访问控制中职责分离的设计与实现

职责分离是基于角色的访问控制技术中保障实现最小特权原理的关键因素。基于实际项目开发经验,详细阐述了基于角色的访问控制技术中职责分离实现的目的、原理、实现逻辑以及具体的实现方法。     

Solaris下基于角色访问控制模型的研究与应用

操作系统作为信息系统的基础,其安全性不容忽视.访问控制是维护和保证系统安全的重要方式,而基于角色访问控制(RBAC)是访问控制领域新兴的热点.以Sun公司的开源操作系统Solaris为例,分析了RBAC模型的结构和工作原理,同时,对Solaris下角色访问控制的具体实现进行了研究,提出了一种针对超级用户权限的控制方法,更好地实现了最小特权原则.     

SCA核心框架安全服务的研究与实现

SCA核心框架是基于分布式CORBA中间件设计实现的,同时核心框架又是一个开放式的架构。安全性几乎影响SCA体系结构的每个方面。简要介绍了SCA的安全性隐患及需求。着重讨论了基于CORBA安全服务的波形软件认证和访问控制。     

基于物联网的小区安防系统的设计与实现

随着计算机技术和物联网技术的发展和进步,建设基于物联网的小区安防系统对于提开小区的品味和物业管理水平,为小区的所有业主营造一个安全、舒适的居住环境具有很大的帮助.主要介绍了小区安防系统中的自动报警系统、电子门禁系统、闭路电视监控系统、电子巡更系统等4个子系统的实现方法和基本工作原理.     

基于元数据和角色控制的用户权限管理

通过角色控制模型将用户与某一具体功能分离,使用户与他所属的角色相对应。通过给角色授权来实现用户与某一具体功能的连接。这既减轻了系统管理员的工作量又通过角色控制的分离机制提高了系统的安全性。在实现上使用元数据管理功能对应的控件的信息,当系统管理员管理用户权限时,系统从元数据中获取对应信息。通过基于元数据的自定义用户权限管理控件生成整个系统的功能列表,系统管理员分配用户角色,并为该角色授权。通过实际的项目开发,验证了此方法可以有效地实现对用户权限控制,同时增强了系统的安全性,提高了系统的可维护性,大大降低了系统维护的代价。     

A guide to NBS computer security literature

This bibliography lists the many special reports and technical studies in the field of computer security that have been published by the U.S. National Bureau of Standards [NBS]. In addition to an abstract of each of the published volumes, there is an index of key topics included in the more than 40 volumes.     

A new method for synthesizing multiple-period adaptive-repetitive controllers and its application to the control of hard disk drives

This paper introduces a new method for synthesizing multiple-period repetitive controllers. The main innovations in the synthesis procedure presented in this article are two. The first one is that this technique yields a solution compatible with the integration of the computed multiple-period repetitive controller into a minimum-variance adaptive control scheme. The second innovation is that the solution is period-recursive, reducing the complexity of controller synthesis considerably when compared with other methods available in the literature. To exemplify the synthesis procedure, a multiple-period repetitive controller is designed and integrated into an adaptive-repetitive control scheme used in the track-following control of a commercial hard disk drive. Experimental results show the effectiveness of the presented approach.     

A model-free design of reduced-order controllers and application to a DC servomotor

This paper presents a new model-free technique to design fixed-structure controllers for linear unknown systems. In the current control design approaches, measured data are used to first identify a model of the plant, then a controller is designed based on the identified model. Due to errors associated with the identification process, degradation in the controller performance is expected. Hence, we use the measured data to directly design the controller without the need for model identification. Our objective here is to design measurement-based controllers for stable and unstable systems, even when the closed-loop architecture is unknown. This proposed method can be very useful for many industrial applications. The proposed control methodology is a reference model design approach which aims at finding suitable parameter values of a fixed-order controller so that the closed-loop frequency response matches a desired frequency response. This reference model design problem is formulated as a nonlinear programming problem using the concept of bounded error, which can then be solved to find suitable values of the controller parameters. In addition to the well-known advantages of data-based control methods, the main features of our proposed approach are: (1) the error is guaranteed to be bounded, (2) it enables us to avoid issues related to the use of minimization methods, (3) it can be applied to stable and unstable plants and does not require any knowledge about the closed-loop architecture, and (4) the controller structure can be selected a priori, which means that low-order controllers can be designed. The proposed technique is experimentally validated through a real position control problem of a DC servomotor, where the results demonstrate the efficacy of the proposed method.     

一种基于椭圆曲线加密算法解决物联网网络安全和效率问题的设计

为应对物联网在日趋增大的应用中所出现的网络安全问题,尤其是以ONS查询中所存在的安全威胁为主要的EPCglobal网络安全问题,满足物联网网络系统的稳定性和高效性需求,设计了一种基于椭圆曲线加密算法解决物联网EPCglobal网络安全的协议,包含将椭圆曲线加密算法应用于ONS查询中,并将DNSSec运用于ONS服务之中。整个协议设计充分利用了椭圆曲线加密算法的安全性与高效性。最后以实例验证了协议的可行性。     

Characterization,Modeling and H∞ control of n‐DOF Piezoelectric Actuators: application to A 3‐DOF Precise Positioner

This paper deals with the characterization, the modeling and the closed‐loop control of multivariable piezoelectric actuators, with an application to a 3‐DOF piezoelectric tube scanner, widely used in precise positioning. These actuators are typified by hysteresis and creep nonlinearities, badly damped oscillation and strong couplings between their axis. First, during the modeling, we propose to decouple the system and to use a linear model where the couplings and the two nonlinearities are integrated through an external fictive disturbance. From the obtained monovariable systems, monovariable H_∞ controllers are calculated by using specifications based on model approximation. The experimental tests demonstrate the efficiency of the method to reject simultaneously the couplings, hysteresis, creep and badly damped oscillations. Furthermore, the bandwidth of the closed‐loop and the open‐loop systems are compared and the results show that the proposed control technique allows to achieve a convenient closed‐loop bandwidth and precision for all the axis of the precise positioner.