铂电阻Pt100特性数学模型

为了满足自动检测和智能仪表的需要,提出了一种基于余弦基神经网络的传感器特性建模算法,提出了该余弦基神经网络算法的收敛定理,并以铂电阻Pt100为例给出了传感器特性数学模型的建模步骤。计算机仿真结果表明了该算法在传感器特性建模过程中的有效性和优异性能。     

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。     

The role of temporal parameters in a thalamocortical model of analogy

How multiple specialized cortical areas in the brain interact with each other to give rise to an integrated behavior is a largely unanswered question. This paper proposes that such an integration can be understood under the framework of analogy and that part of the thalamus and the thalamic reticular nucleus (TRN) may be playing a key role in this respect. The proposed thalamocortical model of analogy heavily depends on a diverse set of temporal parameters including axonal delay and membrane time constant, each of which is critical for the proper functioning of the model. The model requires a specific set of conditions derived from the need of the model to process analogies. Computational results with a network of integrate and fire (IF) neurons suggest that these conditions are indeed necessary, and furthermore, data found in the experimental literature also support these conditions. The model suggests that there is a very good reason for each temporal parameter in the thalamocortical network having a particular value, and that to understand the integrated behavior of the brain, we need to study these parameters simultaneously, not separately.     

The role of trust in e-commerce relational exchange: A unified model

Recently, studies of B2C e-commerce have used intention theory to understand the role of trust of Internet transactions but most have investigated only a component of e-commerce (e.g., initial adoption or continuance) and neglected the role of good relations with the consumer in ensuring a successful sustained relationship. Therefore, a model that went beyond intention and included key relational concepts (satisfaction, value, loyalty, etc.) was developed. Trust and its components are a major part of this model, which was based on strong theoretical foundations. Fifteen hypotheses were formulated. Data on the constructs were collected from 420 respondents and analyzed using elliptical re-weighted least squares as the estimation method to test model validity and the hypotheses. An additional relationship between satisfaction and customer loyalty was investigated. Implications for researchers and practitioners are discussed.     

支持动态角色切换的RBAC模型

动态角色切换是信息系统依据用户属性改变而部分或整体改变用户-角色指派的一种自动授权机制。本文将动态角色切换引入到RBAC96模型,论述了动态角色切换的各种形态、不同切换间的相互关系及模型实现。基于动态角色切换,系统可以自动处理触发角色切换条件而引起的用户-角色指派变更问题,整个过程无须人工参与,减轻了系统管理员的工作负担,提高了授权管理的效率与安全性。     

基于角色和规则引擎的UCON应用模型

UCON是一种基于属性的下一代访问控制模型,但其高度抽象,难于直接应用,为此提出了一种基于角色和规则引擎的UCON应用模型UCON-ABRR.该模型通过引入角色这一属性,便于实现基于角色的用户管理;并基于规则引擎来制定访问规则和实施访问控制策略,不仅支持UCON的两个重要特征:属性易变性和决策过程连续性,而且具有很好的可操作性.该模型具有通用性,将其应用于云存储场景中,达到了预期的访问控制效果.     

基于属性和角色的访问控制模型

针对Web资源访问控制对访问控制策略灵活性、动态性以及权限管理便捷性的需求,提出一种基于属性和角色的访问控制模型ACBAR,对模型中的元素、关系及规则进行了形式化定义。给出了ACBAR模型的应用实例及相关访问控制策略,并对模型的安全性和应用复杂度进行了分析。ACBAR模型在遵循最小特权和职责分离等安全原则的基础上,相对于RBAC模型有效降低了角色管理的复杂度,支持灵活、动态的Web资源访问控制策略。     

基于角色理论的RBAC96模型改进

在分析RBAC96模型的基础上,从角色概念及角色间关系的角度分析其不明确之处;通过角色理论中的可计算角色模型,改进RBAC96模型,使其具有更好的扩展性。     

Device-physics-based analytical model for SET pulse in sub-100 nm bulk CMOS Process

Through revising the process of charge collection for reversed drain-bulk junction,a bias-dependent SPICE model is proposed which includes the bipolar amplification effect that cannot be ignored in PMOS.The model can capture the plateau effect,and produce current and voltage pulse shapes and widths that are consistent with TCAD simulation.Considering the case of connecting load,it is still valid.For combination and sequential logic circuits,the SET pulsewidths and LET upset threshold from SPICE model are consistent with TCAD simulations.     

100MHz的440BX芯片组

主要介绍Ｉｎｔｅｌ公司新近发布的支持１００ＭＨｚ外频的４４０ＢＸＡＧＰｓｅｔ,同时详细分析了在使用内建该芯片组的主板时必须注意的一些问题。     

A study of real-time and 100 billion agents simulation using the Boids model

In high-performance computing of multi-agent systems, there often exists a load imbalance that slows down the calculation. In this paper, we discuss the parallelization of the Boids model for simulating a swarm intelligence. We apply the multi-level hierarchy of parallelism to the Boids model to mitigate the load-imbalance problem. To eliminate numerical errors due to parallelization, we apply pseudo-quadruple arithmetic. The parallel performance is evaluated on three major architectures, including many-core processors on an x86-based server with GPUs, and the Earth Simulator. The parallelization can decrease the negative effects of a load imbalance to almost zero in a simulation of 50 million agents. In addition, the parallelization guarantees the reproducibility of the results in a sequential execution. The strong scaling shows the potential to complete a simulation in real-time on the Earth Simulator. In addition, the weak scaling shows the ability to calculate 100 billion agents within a reasonable amount of time.     

The role of initial tumor biomass size in a mathematical model of periodically pulsed chemotherapy

The dosage and frequency of a chemotherapy regimen are important determinants for its success. Many research studies have attempted to identify optimal treatment strategies for certain purposes such as minimizing the tumor burden, maximizing the normal cells as well as the dose, and minimizing cytotoxicity to normal cells. In this paper, a combination of mathematical and numerical analysis is applied to study the effect of initial tumor biomass using a competition model describing tumor–normal cell interaction with periodically pulsed chemotherapy. Some properties of the set of initial tumor and normal cell biomasses for successful treatment are derived. On the basis of these properties, a numerical method is constructed for locating the boundary of such a set. The boundary identifies the ability of a chemotherapeutic treatment to eliminate a tumor. The optimal dosage and frequency for a large tumor are discussed. The numerical results show that tumor–host interactions have a great effect on the outcome of the treatment. The effect of resistant tumor subpopulations is also discussed.     

基于双层角色映射的跨域授权管理模型

针对传统跨域授权管理模型角色设置方法单一,以及有可能出现隐蔽提升、职责分离冲突等问题,提出一种基于双层角色结构的跨域授权管理模型。通过在管理域内设置双层角色,使得角色的设置与管理更加符合现实需求;采用单向角色映射的方式杜绝映射环路;引入属性、条件等动态因素,实现了权限的动态调整。采用动态描述逻辑刻画了模型中的概念、关系及管理动作。对模型的安全性分析表明,该模型满足自治性和安全性原则。     

RBAC模型中角色继承关系的研究与改进*

针对RBAC96模型中私有权限实现方法的不足,分析了现有改进方案的研究现状和不足,引入继承属性的概念,通过继承属性值实现权限公有与私有的划分,提出了角色继承时只创建继承关系的继承方案。引入权限重载概念,给出了多角色继承及权限重载时的冲突解决规则,采用广度优先搜索算法实现了角色权限的动态获取;结合实例说明了角色继承、权限重载、解除继承关系的实现方法。     

Enforcing role based access control model with multimedia signatures

Recently ubiquitous technology has invaded almost every aspect of the modern life. Several application domains, have integrated ubiquitous technology to make the management of resources a dynamic task. However, the need for adequate and enforced authentication and access control models to provide safe access to sensitive information remains a critical matter to address in such environments. Many security models were proposed in the literature thus few were able to provide adaptive access decisions based on the environmental changes. In this paper, we propose an approach based on our previous work [B.A. Bouna, R. Chbeir, S. Marrara, A multimedia access control language for virtual and ambient intelligence environments, In Secure Web Services (2007) 111–120] to enforce current role based access control models [M.J. Moyer, M. Ahama, Generalized role-based access control, in: Proceedings of International Conference on Distributed Computing Systems (ICDCS), Phoenix, Arizona, USA, 2001, pp. 391–398] using multimedia objects in a dynamic environment. In essence, multimedia objects tend to be complex, memory and time consuming nevertheless they provide interesting information about users and their context (user surrounding, his moves and gesture, people nearby, etc.). The idea behind our approach is to attribute to roles and permissions, multimedia signatures in which we integrate conditions based on users’ context information described using multimedia objects in order to limit role activation and the abuse of permissions in a given environment. We also describe our architecture which extends the known XACML [XACML, XACML Profile for Role Based Access Control (RBAC), <http://docs.oasis-open.org/xacml/cd-xacml-rbac-profile-01.pdf>, 2008] terminology to incorporate multimedia signatures. We provide an overview of a possible implementation of the model to illustrate how it could be valuable once integrated in an intelligent environment.