Logical control in automatic systems

The possibility of applying multifunctional logical modules to construct systems of automatic control, which can function when the object information is incomplete, is discussed. Two new functional modules providing implementation of the systems of Boolean formulas from the classes of noniterated ordered and unordered Boolean functions and from the class of iterated ordered arbitrary normal Boolean formulas of h letters and systems of Boolean formulas both with argument omissions and without them are shown. The main properties of the closed system of automatic control, which is developed on the basis of the presented modules, are considered, and some recommendations on its application are given.     

轨道车辆人机界面软件冗余设计与可靠性分析

人机界面软件的可靠性直接影响轨道车辆控制系统,甚至轨道车辆的可靠运行。为了提高人机界面软件的可靠性,对人机界面软件进行了冗余设计,在一些重要的功能模块中加入了冗余机制。综合考虑功能模块的可靠性要求、其自身的复杂度、实施冗余的代价等因素,采用了N-版本程序设计、恢复块技术等冗余技术。对进行冗余设计后的人机界面软件,使用基于场景的可靠性评估方法,分析了它的可靠性,并与冗余设计前进行对比。     

Cooperative control of modular space robots

Modular self-assembling on-orbit robots have the potential to reduce mission costs, increase reliability, and permit on-orbit repair and refueling. Modules with a variety of specialized capabilities would self-assemble from orbiting inventories. The assembled modules would then share resources such as power and sensors. As each free-flying module carries its own attitude control actuators, the assembled system has substantial sensor and actuator redundancy. Sensor redundancy enables sensor fusion that reduces measurement error. Actuator redundancy gives a system greater flexibility in managing its fuel usage. In this paper, the control of self-assembling space robots is explored in simulations and experiments. Control and sensor algorithms are presented that exploit the sensor and actuator redundancy. The algorithms address the control challenges introduced by the dynamic interactions between modules, the distribution of fuel resources among modules, and plume impingement.     

Analysis of the possibility of local diagnosis in computer systems with circulant structure based on redundancy in the number of analyzed testing results

Local diagnosis at multiple faults when a faultless/faulty state for each module is identified only by the results of comparative analysis of testing results of the modules that have physical connections with diagnosable module is considered. Conditions at which the state can be defined not for all modules (dead state) are studied. Features of the dead state for separate modules and for the system on the whole, the use of which allows reducing the labor intensiveness of the analysis of local diagnosability of a system, are obtained. In the paper, the possibility of redundancy in the number of dead states at using the redundancy in the number of testing results participating in comparative analysis is shown for systems with circulant diagnostic structure. It is proved that for systems with optimal circulant diagnostic structure such redundancy makes a sufficient condition for excluding dead states.     

Using multi-sensor data fusion for vibration fault diagnosis of rolling element bearings by accelerometer and load cell

This paper presents a new method for bearing fault diagnosis using the fusion of two primary sensors: an accelerometer and a load cell. A novel condition-based monitoring (CBM) system consisting of six modules: sensing, signal processing, feature extraction, classification, high-level fusion and decision making module has been proposed. To obtain acceleration and load signals, a work bench has been used. In the next stage, signal indices for each signal in both time and frequency domains have been calculated. After calculation of signal indices, principal component analysis is employed for redundancy reduction. Two principal features have been extracted from load and acceleration indices. In the fourth module, K-Nearest Neighbor (KNN) classifier has been used in order to identify the condition of the ball bearing based on vibration signal and load signal. In the fifth module, a high-level sensor fusion is used to derive information that would not be available from single sensor. Based on situation assessment carried out during the training process of classifier, a relationship between bearing condition and sensor performance has been found. Finally, a logical program has been used to decide about the condition of the ball bearing. The test results demonstrate that the load cell is powerful to detect the healthy ball bearings from the defected ones, and the accelerometer is useful to detect the location of fault. Experimental results show the effectiveness of this method.     

Self-Repairing Algorithm of Lattice-Type Self-Reconfigurable Modular Robots

Self-reconfigurable modular robots consist of many identical modules. By changing the connections among modules, the configuration of the robot can be transformed into other configurations. For the self-reconfigurable modular robot, one of its main functions is its self-repairing ability. First, the module of the lattice-type self-reconfigurable robot is presented. It is composed of a central cube and six rotary arms. On each rotary arm the docking mechanism is designed to show the self-repairing ability. Second, the basic motion of the self-reconfigurable robot is described to change the positions of the module. The state matrix and the location matrix are proposed to describe the connection states. Third, a self-repairing algorithm based on the positions of the faulty modules is presented. The algorithm applies the Breadth-First-Search method and the Depth-First-Search method to find a locomotion path by which the faulty module is ejected and replaced by a spare module. At last, a simulation on the fourth-order lattice-type self-reconfigurable robot consisting of 729 modules shows the feasibility and effectiveness of this self-repairing algorithm in three dimensions.     

Optimization models for reliability of modular software systems

The authors present optimization models for software systems that are developed using a modular design technique. Four different software structures are considered: one program, no redundancy; one program, with redundancy; multiple programs, no redundancy; and multiple programs, with redundancy. The optimization problems are solved by using the authors' version of established optimization methods. The practical usefulness of this study is to draw the attention of software practitioners to an existing methodology that may be used to make an optimal selection out of an available pool of modules with known reliability and cost. All four models maximize software reliability while ensuring that expenditures remain within available resources. The software manager is allowed to select the appropriate model for a given situation     

Multi-level redundancy optimization in series systems

Single-level systems have been considered in redundancy allocation problems. It may be the best policy in some specific situations, but not in general. In regards to reliability, it is most effective to duplicate the lowest objects, because parallel-series systems are more reliable than series-parallel systems. However, the smaller an object is, the more time and higher accuracy are needed for duplicating it, and so, redundancy cost can be decreased by using modular redundancy. Therefore, providing redundancy at high levels like as modules or subsystems, can be more economical than providing redundancy at low level of components. In this paper, the problem in which redundancy is available at all levels in a series system is addressed and a mixed integer programming model is presented. A heuristic algorithm and a genetic algorithm are proposed to solve the problem and some examples illustrate the procedure.     

基于Web Services系统登录日志的实现

目前高校内各部门的管理信息系统都拥有独立的记录登录日志和读取登录日志的模块,从而造成了业务逻辑的重复和数据的冗余。针对这种情况提出了一种基于WebServices的系统登录日志技术,使各异构系统能够统一调用登录日志的WebServices。这种方案充分利用了现有的网络资源,有效地避免数据与业务逻辑的冗余,实现了模块和数据的重用。     

一种应用于SpaceWire路由器动态部分重构的容错技术

为满足航天器有效载荷间高速数据多路传输未来发展和空间抗辐射的需求,研究了一种应用于SpaceWire路由器动态部分重构的容错技术。在SpaceWire总线标准网络层分析的基础上,对cell矩阵无阻塞路由增添HanMing编码实现纠一检二,当检测出大于一个错误不能纠正时,采用局部重构的方式对有误的单个cell单元进行三重冗余重构,同时采用Partition Pin来代替传统的总线宏作为静态模块和动态模块的传输枢纽,并对容错前后路由器的资源和延时时间进行了评估和比较。实验结果表明,比将整个路由cell矩阵三模冗余,该方法能够节约硬件资源和减少延迟时间。     

基于SFTA的桥接模式安全性分析

采用软件故障树分析法,通过一个应用桥接模式的实例研究在软件设计中引入设计模式对软件安全性的影响。结果表明,单纯引入桥接模式,软件的安全性约降低50%,但引入设计模式使得软件模块之间解耦合,通过加入双余量设计,可以使软件安全性提高2个数量级。该结论对安全关键软件面向对象的设计具有指导作用。     

Design and dock analysis for the interactive module of a lattice-based self-reconfigurable robot

In this paper, a novel, lattice-based self-reconfigurable modular robot is presented. Each module is composed of a cubic part and six rotary sides. There are two holes and two extension pegs on each side. Rotary motion is generated by a motor with a reducer by using cone-shaped gears, clutches and so on. Its quick disconnect/connect mechanism is analyzed. A face-face incidence matrix (FFIM) is proposed to describe the relationship between modules in detail. The states of docking and constraint between modules are analyzed with the geometric method and the contact force of docking is described. Lastly, a self-reconfigurable robot consisting of five similar modules designed to pass the groove in simulation with the proposed motion rules and its FFIM is presented. The results verify that the above analysis is effective.     

一种基于Paxos算法的容错机制

针对在普通的硬件和网络环境下实现系统数据的高可用性的目标,设计了一个由两个松耦合的模块组成的容错机制。该机制的核心使用了高效的共识算法Paxos。描述了这一容错机制的架构和主要模块,日志层的实现算法和数据层冗余机制。给出了该机制能够处理的各种故障。实验证明系统的稳定可靠,性能良好。     

Problems of international standardization of Videotex services

Interactive and broadcast Videotex are media of communication, and as such require international standardization. This report discusses various proposals for the international definition of character sets, attributes for graphic design, and data transmission codes suited to both. Emphasis is put on the standardization of a comprehensive character set for all languages based on latin letters, and on the definition of a set of control characters which consider all requirements known up to date, and include some redundancy for future extensions.     

Analytical redundancy and the design of robust failure detection systems

The failure detection and identification (FDI) process is viewed as consisting of two stages: residual generation and decision making. It is argued that a robust FDI system can be achieved by designing a robust residual generation process. Analytical redundancy, the basis for residual generation, is characterized in terms of a parity space. Using the concept of parity relations, residuals can be generated in a number of ways and the design of a robust residual generation process can be formulated as a minimax optimization problem. An example is included to illustrate this design methodology.     

基于FPGA的多传感器融合单元的设计研究

面向空间探测应用的电子系统设计对有效载荷温度采集值的可信度要求较高.首先分析了常用的静态TMR(TripleModular Redundancy)模型的特点,并提出了一种改进方法;简要描述了传感变送部分电路设计,并着重阐述了基于FPGA的数据采集和表决模块的硬件实现;最后结合测试数据证明了该数据融合单元设计实现的合理性和可靠性.     

Predictive Text Typing System for the Ukrainian Language

This paper investigates the intellectualization of text input using a system for accelerated input of texts into digital devices with a view to constructing a model of a corpus of the Ukrainian spoken language and a text typing system based on this model. Such a system uses a smaller number of commands to input letters and predicts variants of words on the basis of the corpus of words and word combinations for communication. It is experimentally shown that the input of texts using four and six command keys is rather efficient for the constructed corpus.     

列车通信网络协议栈的实时性研究

针对传统列车网络控制系统无法满足高速列车实时运行控制的不足,基于列车通信网络(TCN)建立了一种综合多功能车辆总线(MVB)、绞线式列车总线(WTB)和实时协议(RTP)在内的完备的设备协议栈模型。依据硬实时系统指标,结合列车的实际应用,设计出相应的协议模块,并构建了精确的验证平台。仿真实验验证了实时指标和列车初运行自动配置、介质分配、小数据交换等实时特征,建立的协议栈模型实时性强,能够提供高速列车运行控制下的安全性保证。     

冗余控制系统在炼铁厂TRT发电装置中的应用

鉴于TRT高炉煤气发电装置的重要性且对其可靠性的要求较高,因而该发电装置的控制系统选用了西门子S7—400H冗余系统。文中简述了TRT高炉煤气发电装置的构成,介绍了S7—400H冗余系统的硬件结构、模块参数和各程序模块的具体功能。该控制系统投运后,TRT高炉煤气发电装置运行可靠,效果良好。