Building hybrid access control by configuring RBAC and MAC features

ContextRole-Based Access Control (RBAC) and Mandatory Access Control (MAC) are widely used access control models. They are often used together in domains where both data integrity and information flow are concerned. However, there is little work on techniques for building hybrid access control of RBAC and MAC.ObjectiveIn this work, we present a systematic approach for developing a hybrid access control model using feature modeling with the aim of reducing development complexity and error-proneness.MethodIn the approach, RBAC and MAC are defined in terms of features based on partial inheritance. Features are then configured for specific access control requirements of an application. Configured features are composed homogeneously and heterogeneously to produce a hybrid access model for the application. The resulting hybrid model is then instantiated in the context of the application to produce an initial design model supporting both RBAC and MAC. We evaluate the approach using a hospital system and present its tool support.ResultsRBAC and MAC features that are specifically configured for the application are systematically incorporated into a design model. The heterogeneous features of RBAC and MAC are not only present in the resulting model, but also semantically composed for seamless integration of RBAC and MAC. Discharging the proof obligations of composition rules to the resulting model proves its correctness. The successful development of the prototype demonstrates its practicality.ConclusionFeatures in the access control domain are relatively small in size and are suitable to be defined as design building blocks. The formal definition of partial inheritance and composition methods in the presented approach enables precisely specifying access control features and feature configuration, which paves the way for systematic development of a hybrid access control model in an early development phase.     

混合系统在matlab环境下的建模和仿真

混合系统是集连续动态系统和离散事件为一体的复杂动态系统,是近年来控制理论研究领域的热门课题.由于混合系统既含连续变量义含离散事件,给处理这类系统带来了复杂性.一般混合系统建立模方法有:混合自动机,混合petri,时段演算及其扩展等模型.在概述混合系统概念与特点的基础上,介绍了混合系统研究中的建模与仿真问题.结合超市冰柜系统用混合自动机建模,并用MATLAB中的SIMULINK和STATEFLOW进行仿真.仿真结果表明效果很好,为系统分析和设计提供了有力的工具.     

复杂产品一体化优化设计框架研究

复杂产品的一体化设计过程涉及多个互相关联的分系统,支持一体化设计的优化框架需要能够集成优化设计过程中涉及的异构应用并进行优化,从而辅助设计人员对总体与各分系统的优化设计进行验证.在分析国内外复杂产品一体化优化设计研究现状的基础上,基于C/S模式提出了一种支持复杂产品一体化设计的优化框架体系结构.该优化框架包括两方面的关键技术：包装器集成技术和混合遗传算法.异构应用首先按照接口规范包装后形成可发布的共享组件,便于构建一体化设计过程.在此基础上,通过混合遗传算法等辅助设计人员进行优化计算.最后阐述了目前的工作和下一步需要解决的问题.     

On the limit cycle stabilization of a DC/DC three-cell converter

This paper investigates a new state feedback controller design for DC/DC three-cell converter. The high dynamic performances of the converter have been translated into a desired limit cycle stabilization problem. The state feedback is established using hybrid automaton formalism, which allows us to design independently a transitory state and steady state control schemes. Finite-time convergence of the trajectory to the steady state and the local asymptotic stability of the desired limit cycle under the proposed controller are proved analytically. Simulation and experimental results confirm the theoretical results and show the effectiveness and robustness of the hybrid controller in spite of load variations.     

H2CM: A holonic architecture for flexible hybrid control systems

Several studies typically arise from the interaction of discrete planning algorithms or control and continuous processes, normally called hybrid control systems. It consists in three distinct levels, the controller, the plant and the interface. Hybrid control systems are conventionally modeled by switching patterns using the whole system instead of atomic resource. Therefore, the reconfiguration process is complex because it must take into account the system as a whole, making the hybrid control systems inflexible and more susceptible to uncertainties. The need for flexibility thus leads several teams to investigate the application of holonic paradigm to hybrid control systems. The objective of this paper is to demonstrate the possibility to apply almost directly a holonic discrete-event based reference architecture to hybrid control systems. A case study of industrial electricity generation process was taken, specifically a combined cycle plant (CCP) for verifying the proper operation of the proposed architecture.     

基于动态模拟技术的混动车辆发动机电控单元检测系统设计

电控单元是混动车辆发动机中的重要组成部分,对于发动机以及混动车辆的行驶性能产生直接影响,为保证电控单元的运行正常,利用动态模拟技术,优化设计了混动车辆发动机电控单元检测系统。改装温度、转速等传感器设备以及信号处理器设备,调整系统电路的连接方式,实现硬件系统的优化。利用动态模拟技术模拟混动车辆发动机电控过程,结合不同故障类型下电控单元的运行特征,设置系统的检测标准。采集电控单元输出信号,从时域和频域两个方面提取信号特征,最终通过特征匹配确定电控单元状态、故障类型以及故障位置,实现系统的电控单元检测功能。综合混动车辆发动机的三种运行场景,通过系统测试实验得出结论：与传统检测系统相比,优化设计系统的漏检率和误检率分别降低了2.59%和2.05%,由此证明优化设计系统具有良好的检测功能。     

A singularity-free motion control algorithm for robot manipulators—a hybrid system approach

This paper presents the design and implementation of a singularity-free tracking algorithm for robot manipulators using a hybrid system approach. A hybrid robot motion controller is designed to ensure feasible robot motion in the neighborhood of kinematic singularities. The hybrid control system has a two-layered hierarchical structure, a discrete layer and a continuous layer. The robot workspace is partitioned into subspaces based on the singular configurations of the robot. Switching between continuous controllers is involved when the robot travels across the subspaces. With the hybrid controller, the robot can work at the vicinity of singular configurations, but also can go through and stay at the singular configurations. The stability of the hybrid system is investigated using multiple Lyapunov function theory. Experimental results have demonstrated the advantages of the hybrid robot motion control method.     

任意切换时间下的二维线性混合系统的滑模控制

由于混合系统的复杂性,设计出能保证混合系统在任意切换时间下都能稳定的控制是比较困难的。为了突出滑模控制设计的思想,文章针对一类二维线性混合系统,提出通过确保混合系统实现滑动模的充分条件来保证系统的稳定性,并得到相应的控制律。仿真结果表明了该控制律的有效性。     

Hybrid Fuzzy Modelling for Model Predictive Control

Model predictive control (MPC) has become an important area of research and is also an approach that has been successfully used in many industrial applications. In order to implement a MPC algorithm, a model of the process we are dealing with is needed. Due to the complex hybrid and nonlinear nature of many industrial processes, obtaining a suitable model is often a difficult task. In this paper a hybrid fuzzy modelling approach with a compact formulation is introduced. The hybrid system hierarchy is explained and the Takagi–Sugeno fuzzy formulation for the hybrid fuzzy modelling purposes is presented. An efficient method for identifying the hybrid fuzzy model is also proposed. A MPC algorithm suitable for systems with discrete inputs is treated. The benefits of the MPC algorithm employing the hybrid fuzzy model are verified on a batch-reactor simulation example: a comparison between the proposed modern intelligent (fuzzy) approach and a classic (linear) approach was made. It was established that the MPC algorithm employing the proposed hybrid fuzzy model clearly outperforms the approach where a hybrid linear model is used, which justifies the usability of the hybrid fuzzy model. The hybrid fuzzy formulation introduces a powerful model that can faithfully represent hybrid and nonlinear dynamics of systems met in industrial practice, therefore, this approach demonstrates a significant advantage for MPC resulting in a better control performance.     

A framework for hybrid model predictive control in mineral processing

Model Predictive Control (MPC) is an advanced technique for process control that has seen a significant and widespread increase in its use in the process industry since its introduction. In mineral processing, in particular, several applications of conventional MPC can be found for the individual processes of crushing, grinding, flotation, thickening, agglomeration, and smelting with varying degrees of success depending on the variables involved and the control objectives. Given the complexity of the processes normally found in mineral processing, there is also great interest in the design and development of advanced control techniques which aim to deal with situations that conventional controllers are unable to do. In this aspect, Hybrid MPC enables the representation of systems, incorporating logical variables, rules, and continuous dynamics. This paper firstly presents a framework for modeling and representation of hybrid systems, and the design and development of hybrid predictive controllers. Additionally, two application examples in mineral processing are presented. Results through simulation show that the control schemes developed under this framework exhibit a better performance when compared with conventional expert or MPC controllers, while providing a highly systematized methodology for the analysis, design, and development of hybrid MPC controllers.     

VOLTAGE REGULATION OF A BUCK BOOST CONVERTER—A HYBRID CONTROL APPROACH

In this paper, the output voltage regulation problem in a buck boost converter is defined as a hybrid control problem. For control design, the mutually interacting continuous and discrete dynamics are modeled as a hybrid automaton. Thus, the control problem is defined as a guard selection problem of the hybrid automaton. The system trajectory is switched between different modes based on the guards to achieve the required voltage regulation. The guards defined are fixed surfaces represented in terms of the state variables for a given operating condition. The logic‐based switching in the state plane is stable in terms of the chaotic and bifurcation behavior. The effectiveness of the control scheme for buck and boost operation under line and load disturbances is demonstrated by simulation in the MATLAB‐SIMULINK environment and the results are presented.     

Hybrid learning concepts based on self-organizing neural networks for adaptive control of walking machines

Online learning of complex control behaviour of autonomous mobile robots like walking machines is one of the current research topics. In this article, a hybrid learning architecture based on reinforcement learning (RL) and self-organizing neural networks for online adaptivity is presented. The hybrid concept integrates different learning methods and task-oriented representations as well as available domain knowledge. The proposed concept is used for RL of control strategies on different control levels on a walking machine.     

基于Matlab状态流的混杂系统仿真设计

混杂系统是集连续动态和离散事件为一体的复杂系统,是近十余年来控制理论研究领域的热门课题,混杂动态系统的研究为解决一类复杂的、非线性的大系统提供了一个很好的理论框架,计算机仿真是分析和研究混杂系统的有效工具。该文在分析混杂系统仿真关键问题的基础上,提出如何应用MATLAB环境中的状态流工具箱,实现基于混杂自动机模型的混杂系统仿真,并就典型混杂系统给出仿真实例。结果表明,应用MATLAB状态流工具箱进行混杂系统仿真,具有很好的可视化,而且混杂系统的离散和连续两部分可以很好的同步协调,结构简单而明了,效果很好。     

Hybrid system modeling using the SIMANLib and ARENALib Modelica libraries

The ARENALib and SIMANLib Modelica libraries replicate the basic functionality of the Arena simulation environment and the SIMAN language. These libraries facilitate describing discrete-event models using the Arena modeling methodology. ARENALib and SIMANLib models can be combined with other Modelica models in order to describe complex hybrid systems (i.e., combined continuous-time and discrete-event systems). The implementation and design of SIMANLib and ARENALib is discussed. The ARENALib components have been built in a modular fashion using SIMANLib. The SIMANLib components have been described as Parallel DEVS models and implemented using DEVSLib, a Modelica library previously developed by the authors to support the Parallel DEVS formalism. The use of Parallel DEVS as underlying mathematical formalism has facilitated the development and maintenance of SIMANLib. The modeling of two hybrid systems is discussed to illustrate the features and use of SIMANLib and ARENALib: firstly, a soaking-pit furnace; secondly, the malaria spread and an emergency hospital. DEVSLib, SIMANLib and ARENALib can be freely downloaded from http://www.euclides.dia.uned.es/.     

学习控制技术·方法应用的发展新动向

分析和概述了当前学习控制系统所采用的技术、学习方法及应用的发展新动向 .从所采用的技术来看 ,学习控制正在从采用单一的技术向采用混合技术的方向发展 ;从学习方法和应用来看 ,学习控制正在从采用较为简单的参数学习向采用较为复杂的结构学习、环境学习和复杂对象学习的方向发展     

A methodology to design a fuzzy logic based supervision of Hybrid Renewable Energy Systems

Hybrid Renewable Energy Systems (HRES) are increasingly used to improve the grid integration of wind power generators. The goal of this work is to propose a methodology to design a fuzzy logic based supervision of this new kind of production unit. A graphical modeling tool is proposed to facilitate the analysis and the determination of fuzzy control algorithms adapted to complex hybrid systems. To explain this methodology, the association of wind generators, decentralized generators and storage systems are considered for the production of electrical power. The methodology is divided in six steps covering the design of a supervisor from the system work specifications to an optimized implementation of the control. The performance of this supervisor is shown with the help of simulations. Finally, the application of this methodology to the supervision of different topologies of HRES is also proposed to bring forward the systematic dimension of the approach.     

基于编码控制机制的混杂系统半全局实用镇定

混杂系统的鲁棒镇定是复杂控制系统领域的重要研究课题之一.提出了一种编码机制下的混杂控制策略,它能有效地克服传统连续反馈控制或不连续反馈控制在处理局部鲁棒镇定平衡点或不变集问题中的局限性,获得更好的控制效果.首先针对编码状态反馈,构建了一般的混杂系统模型来描述编码状态反馈作用下非线性系统的闭环系统模型.然后,基于逆Lyapunov定理开展了非线性系统的混杂控制鲁棒性分析,提出了闭环混杂系统的半全局实用渐近稳定性判据.最后,结合一个经典控制问题来说明所提出控制策略的优越性.     

Assume–guarantee verification of nonlinear hybrid systems with Ariadne

In many applicative fields, there is the need to model and design complex systems having a mixed discrete and continuous behavior that cannot be characterized faithfully using either discrete or continuous models only. Such systems consist of a discrete control part that operates in a continuous environment and are named hybrid systems because of their mixed nature. Unfortunately, most of the verification problems for hybrid systems, like reachability analysis, turn out to be undecidable. Because of this, many approximation techniques and tools to estimate the reachable set have been proposed in the literature. However, most of the tools are unable to handle nonlinear dynamics and constraints and have restrictive licenses. To overcome these limitations, we recently proposed an open‐source framework for hybrid system verification, called Ariadne , which exploits approximation techniques based on the theory of computable analysis for implementing formal verification algorithms. In this paper, we will show how the approximation capabilities of Ariadne can be used to verify complex hybrid systems, adopting an assume–guarantee reasoning approach. Copyright © 2012 John Wiley & Sons, Ltd.     

控制模态转移型系统的稳定切换

离散事件决策子系统和数值反馈子系统合成的混合控制系统呈现出复杂的稳定动态 特性.研究了在达到模态切换周期的控制规则下,相应的系统连续状态轨迹的平稳性.给出了具 有较少约束的李雅谱诺夫型判据,不要求全局一致的李雅谱诺夫函数,不要求每个模态下的能 量函数单调递减.     

基于扩展混成Petri网的CPS无人车系统建模与分析

信息物理融合系统(Cyber-Physical System,CPS)是一个集计算系统、通信系统、感知系统、控制系统和物理系统于一体的复杂系统,其行为是一种由离散计算过程与连续物理过程深度融合并紧密交互的混成行为。针对这种特性,采用混成Petri网对CPS建模,并在此基础上添加时间约束,即对离散变迁关联一个延迟时间,对连续变迁关联一个激发速率函数,同时引入抑止弧和测试弧的概念以提高Petri网的表达能力,由此提出一种新的模型——扩展混成Petri网模型。然后,对CPS应用中无人驾驶车辆系统的躲避障碍物场景进行建模,将建立的模型按照一定的规则转化为与之对应的Simulink模型,并通过Matlab仿真对系统行为及属性进行分析。