A new state space model for the NASA/JPL 70-meter antenna servo controls

A control axis referenced model of the NASA/JPL 70-m antenna structure is combined with the dynamic equations of servo components to produce a comprehansive state variable (matrix) model of the coupled system. An interactive Fortran program for generating the linear system model and computing its salient parameters is described. Results are produced in a state variable, block diagram, and in factored transfer function forms to facilitate design and analysis by classical as well as modern control methods

Root Locus-Based Magnetic Levitation System Stabilization: An Undergraduate Control System Design Approach

The subject of control system design has evolved considerably over the years. Although several design techniques and strategies have been adopted to realize control systems that meet a predetermined set of performance criteria, the fundamental problem remains that of developing controllers to adjust the performance characteristics of a dynamic system in order to obtain a desired output behavior. The dynamic behavior of a magnetic levitation system (MLS) of a ferromagnetic ball is compensated in this paper. Consolidating the exposure of undergraduate students to the rudiments of control system design, the paper employs the classical root locus technique to stabilize the system. A combination of analytical and software-based methods is used to design proportional-derivative and phase-lead compensators based on the linearized model of the system. Complete details of the design approach, from modeling and analysis of the plant to computing the values of the controller parameters, are shown. MATLAB scripts for plotting root loci and simulating the system are provided

AnonyControl: Control Cloud Data Anonymously with Multi-Authority Attribute-Based Encryption

Cloud computing is a revolutionary computing paradigm which enables flexible, on-demand and low-cost usage of computing resources. However, those advantages, ironically, are the causes of security and privacy problems, which emerge because the data owned by different users are stored in some cloud servers instead of under their own control. To deal with security problems, various schemes based on the Attribute- Based Encryption (ABE) have been proposed recently. However, the privacy problem of cloud computing is yet to be solved. This paper presents an anonymous privilege control scheme AnonyControl to address the user and data privacy problem in a cloud. By using multiple authorities in cloud computing system, our proposed scheme achieves anonymous cloud data access, finegrained privilege control, and more importantly, tolerance to up to (N -2) authority compromise. Our security and performance analysis show that AnonyControl is both secure and efficient for cloud computing environment.Comment: 9 pages, 6 figures, 3 tables, conference, IEEE INFOCOM 201

Information Technology of Software Architecture Structural Synthesis of Information System

Information technology of information system software architecture structural synthesis is proposed. It is used for evolutionary models of the software lifecycle, which provides configuration and formation of software to control the realization and recovery of computing processes in parallel and distributed computing resources structures. The technology is applied in the framework of the software requirements analysis, design of architecture, design and integration of software. Method of combining vertices for multilevel graph model of software architecture and automata-based method of checking performance limitations to software are based on the advanced graph model of software architecture. These methods are proposed in the framework of information technology and allow forming a rational structure of the program, as well as checking for compliance with the functional and non-functional requirements of the end user.The essence of proposed information technology is in displaying of the customer's requirements in the current version of the graph model of program complex structure and providing a reconfiguration of the system modules. This process is based on the analysis and processing of the graph model, software module specifications, formation of software structure in accordance with the graph model, software verification and its compilation

Ground-state Stabilization of Open Quantum Systems by Dissipation

Control by dissipation, or environment engineering, constitutes an important methodology within quantum coherent control which was proposed to improve the robustness and scalability of quantum control systems. The system-environment coupling, often considered to be detrimental to quantum coherence, also provides the means to steer the system to desired states. This paper aims to develop the theory for engineering of the dissipation, based on a ground-state Lyapunov stability analysis of open quantum systems via a Heisenberg-picture approach. Algebraic conditions concerning the ground-state stability and scalability of quantum systems are obtained. In particular, Lyapunov stability conditions expressed as operator inequalities allow a purely algebraic treatment of the environment engineering problem, which facilitates the integration of quantum components into a large-scale quantum system and draws an explicit connection to the classical theory of vector Lyapunov functions and decomposition-aggregation methods for control of complex systems. The implications of the results in relation to dissipative quantum computing and state engineering are also discussed in this paper.Comment: 18 pages, to appear in Automatic