Models of closed multimachine computer systems with transient-fault-tolerance and fault-tolerance on the basis of replication under byzantine faults

Consideration was given to the key definitions, notions, and models that may be useful for transient-fault-tolerant and fault-tolerant computing in the unmanned multimachine computer systems having many interconnected autonomous computers without shared memory and centralized control organ and operating with high degree of computational parallelism, that is, executing on different computers simultaneously various tasks which interchange their information. These computations should establish reliable results under byzantine faults and controllable degradation of the system at detection of faults.     

Mutual Information Agreement with the Detection and Identification of Byzantine Faults in Incompletely Connected Multicomputer Systems

A method of the mutual information agreement for incompletely connected multicomputer systems is set out, which ensures the consistent (i.e. simultaneous and identical) detection and identification of faults in an admissible number of computers among all the serviceable computers of the system both by the places of symptoms of faults and their types (malfunctions, programmed malfunctions, or failures).     

Extracting complexes that ensure sufficient structural conditions for system mutual informational agreement in multicomplex systems

We study the possibility to organize a solution in a network of arbitrary structure for a given set of interacting tasks with fault- and transient-fault-tolerance characteristics specified for each problem. For each problem, we distinguish a complex where all computers solve copies of this task (task replication), exchange results, and choose the correct one. The key problem in such computations is system mutual information agreement (SMIA) that ensures coherence of system information in all computers of all complexes under admissible faults. We derive sufficient structural conditions for reaching such a MIA and methods for finding them. We propose an algorithm for distinguishing complexes corresponding to problems being solved in computer networks (if at all possible).     

An approach to self-diagnosis of a newly developed fault in digital systems

An approach to self-diagnosis of a newly developed fault in digital systems is developed via the expanding domain principle. A restricted number of stable multiple faults in components and development of one more fault during diagnosis are admissible. Self-diagnosis is initiated twice and the results generated in these starts are compared for detecting the developed fault and obtaining reliable diagnosis. An example is given to illustrate the self-diagnosis process in a 9-module system.Translated from Avtomatika i Telemekhanika, No. 4, 2005, pp. 127–140.Original Russian Text Copyright © 2005 by Vedeshenkov.This paper was recommended for publication by P.P. Parkhomenko, a member of the Editorial Board     

Mutual Information Agreement in Multicomputer Systems with the Detection and Identification of Byzantine Faults

A method is suggested of the mutual information agreementin multicomputer systems with intercomputer bus-type communication channels and the broadcast way of transfer of intercomputer messages. The method makes it possible to detect and identify symptoms (both by the places of their emergence and by the types of faults, such as malfunctions programmed malfunctions, or failures) of multiple faults of computers and transmitting interfaces (interface devices) with communication channels, which can occur in all cycles of the interchange. In addition, the method enables one to distinguish, first, faults of computers and transmitting interfaces, if it is possible, and, second, the situation of the nondelivery of a message in initial cycles and the situation of the delivery of this message with distortions.     

电子信息系统中信息传输控制技术

信息传输控制技术是决定信息正确传输的关键,该文针对目前电子信息系统中信息传输的现状和特点,提出构件化网络传输控制服务软件的设计方法,采用相关信息传输控制技术,建立信息传输组件架构和传输控制机制应用于工程实践。结果证明,该技术设计解决了目前困扰信息传输的相关实际问题,在提高信息传输的灵活性、实时高效性和可靠性等方面取得了明显的效果。     

Matched processors for quantized control: A practical parallel-processing approach

Deterministic ‘quantized control’ problems are investigated from a novel and often computationally feasible ‘matched processors’ (MPs) perspective. It is noted that a bank of independent MPs, each matched to an admissible decision sequence, can evaluate, given the state and remaining duration, the dynamic performance cost-to-go values corresponding to a suitably selected ‘small’ subset of all admissible decision sequences. By choosing the best admissible decision sequence in this subset and using its first decision at each stage a computationally feasible and generally sub-optimum MP control scheme is produced. This scheme is found to be ideally suited for very-large-scale integration. In particular, for processes that are linear in the state and performance criteria that are quadratic in the state, the cost-to-go reduces to a simple quadratic function of the given state which in turn results in an MP control scheme structure similar to offered VLSI-based digital computers. It is demonstrated that the proposed scheme performs quite well in two experimental examples.     

An approach to self-diagnosis of nonuniform digital systems

An approach to self-diagnosis of the components (modules and communication lines) of nonuniform digital systems consisting of equal numbers of modules of two types (processor, memory) was presented. To carry out checking and self-diagnosis, different connected modules are regarded as subsystems which are checked by the active modules such as processors. Bit-stuck multiple failures of a limited number of component are permitted, whereas no new failures occur in the course of self-diagnosis. The Barsi-Grandoni-Maestrini model is used to describe the results of subsystem testing. It was assumed that the nonuniform system includes a diagnostic monitor initiating checking and self-diagnosis. An example of checking and self-diagnosis of the components of a nonuniform 14-module system was presented.     

一类非确定欠驱动系统的串级模糊滑模控制

本文针对一类含有非确定项的欠驱动系统提出了一种串级模糊滑模控制方法.该方法先选取状态变量中两个相关联的系统状态构造第一级滑动平面,然后将第一级滑模函数作为一个广义状态,与剩下系统状态中的一个状态构造第二级滑动平面,直到所有的系统状态都包含在内构造最后一级滑动平面.同时考虑到系统模型中存在的不确定项,利用模糊逻辑的逼近功能进行估计,文中采用Lyapunov方法求取了控制器的控制律以及模糊逼近的有关参数的自适应律.该串级模糊滑模控制器能够保证各级滑动平面的稳定性,并且在仿真实验中得到了验证.     

Regular linear systems with feedback

We consider a rather general class of infinite-dimensional linear systems, called regular linear systems, for which convenient representations are known to exist both in time and in the frequency domain. We introduce and study the concept of admissible feedback operator for such a system and of well-posedness radius. We show that the closed-loop system obtained from a regular linear system with an admissible feedback operator is again regular and we describe the relationship between the generating operators of the open-loop and closed-loop systems.Part of the results reported here were obtained while the author was visiting FUNDP Namur, under the Belgian Program on Inter-University Poles of Attraction initiated by the Belgian state, Prime Minister's Office, Science Policy Programming. The scientific responsibility is assumed by the author.     

一种DNC信息系统的研究与开发

从信息采集与传输的角度,提出了满足工业实时控制的数控机床DNC信息系统的一种体系结构。以FANUC0-T数控机床为实例,介绍了DNC信息系统中数控机床接口设计技术。并在此基础上,简要分析了NC程序控制工作流程以及DNC计算机与数控机床通信的具体过程。     

信息寄生传输系统设计

本文介绍了寄生传输线的信道特性和信道模型,寄生传输线具有衰减大、输入阻抗小、很强的时变性和干扰大的特点。信道模型为一线性时变系统。整个信息寄生传输系统由控制中心主机部分和监测点终端部分组成,最后说明了系统的软件设计。本文介绍的信息寄生传输系统已成功应用到仓库报警和温湿度检测中。     

Extend the quickest path problem to the system reliability evaluation for a stochastic-flow network

From the point of view of quality management, it is an important issue to reduce the transmission time in the network. The quickest path problem is to find the path in the network to send a given amount of data from the source to the sink such that the transmission time is minimized. Traditionally, this problem assumed that the capacity of each arc in the network is deterministic. However, the capacity of each arc is stochastic due to failure, maintenance, etc. in many real-life networks. This paper proposes a simple algorithm to evaluate the probability that d units of data can be sent from the source to the sink through the stochastic-flow network within T units of time. Such a probability is called the system reliability. The proposed algorithm firstly generates all lower boundary points for (d,T) and the system reliability can then be computed in terms of such points.Scope and purposeThe shortest path problem is a well-known problem in operations research, computer science, etc. Chen and Chin have proposed a variant of the shortest path problem, termed the quickest path problem. It is to find a path in the network to send a given amount of data from the source to the sink with minimum transmission time. More specifically, the capacity of each arc in the network is assumed to be deterministic. However, in many real-life networks such as computer systems, telecommunication systems, etc., the capacity of each arc is stochastic due to failure, maintenance, etc. Such a network is named a stochastic-flow network. Hence, the minimum transmission time is not a fixed number. This paper proposes a simple algorithm to evaluate the probability that the specified amount of data can be sent from the source to the sink through the network within a given time. Such a probability is called the system reliability.     

网络安全战略预警系统的特征信息融合方法

提出将一种特征信息融合的方法一基于Mamdani模糊神经网络的方法引入到战略预警系统的威胁评测中，并进行了相关规则的推理，证实了该方法的可行性及合理性。     

测量数据丢失的随机不确定离散系统的鲁棒H2状态估计

由于频宽有限,或者传感器临时损坏,测量数据在网络中传输时可能会丢失.本文对一类测量数据丢失的不确定离散系统,研究了鲁棒H2状态估计问题.所有的系统矩阵的参数都属丁二给定的凸多面体区域.测量数据的丢失是随机发生的,认为它是已知概率的Bernoulli随机序列.对于所有容许的不确定和可能的数据丢失,采用线性矩阵不等式方法,给出了全阶和降阶的H2滤波器存在的充分条件.数值仿真表明本文所提方法的有效性.     

Generalized processor sharing: Characterization of the admissible region and selection of optimal weights

We consider a two-class Generalized Processor Sharing (GPS) queueing system, in which each class has its specific traffic characteristics and quality-of-service (QoS) requirements. Traffic of both classes is assumed to be Gaussian (a versatile family of models that covers both long-range dependent and short-range dependent traffic). In this paper we address the question how to select the GPS weight values. To do so, we first characterize the admissible region of the system for fixed weights. Then we obtain the realizable region by taking the union of the admissible regions over all possible weight values. The results indicate that, under a broad variety of traffic characteristics and QoS requirements, nearly the entire realizable region can be obtained by strict priority scheduling disciplines. In addition, we indicate how the buffer thresholds, QoS requirements and the traffic characteristics of the two classes determine which class should get high priority.     

Planning and Resource Allocation for Hard Real-time,Fault-Tolerant Plan Execution

We describe the interface between a real-time resource allocation system with an AI planner in order to create fault-tolerant plans that are guaranteed to execute in hard real-time. The planner specifies the task set and all execution deadlines required to ensure system safety, then the resource utilization. A new interface module combines information from planning and resource allocation to enforce development of plans feasible for execution during a variety of internal system faults. Plans that over-utilize any system resource trigger feedback to the planner, which then searches for an alternate plan. A valid plan for each specified fault, including the nominal no-fault situation, is stored in a plan cache for subsequent real-time execution. We situate this work in the context of CIRCA, the Cooperative Intelligent Real-time Control Architecture, which focuses on developing and scheduling plans that make hard real-time safety guarantees, and provide an example of an autonomous aircraft agent to illustrate how our planner-resource allocation interface improves CIRCA performance.     

气象信息管理系统的设计和实现

为使得气象信息管理更加标准化、制度化和科学化,做好气象服务的基础保障工作,针对气象业务、办公服务和管理要求等需求,以云MAS和微信公众服务平台的群发功能为基础,采用HTTP接口开发了面向气象业务系统的信息发送接口,该接口规范管理接入公众服务平台的方式,避免重复的开发功能和用户密码的管理混乱。建立气象信息管理数据库,基于C/S架构,采用前端控制模式以及C#和Python等开发平台,开发了气象信息监管模块,实现了信息监视、综合查询、统计分析、地址管理、参数配置、用户管理和关键字管理等功能。系统投入业务应用运行后,为信息发送至手机终端提供了方便快捷的对接方式和及时可靠的传输通道,提高了发送信息的可靠性和完整性,保障了管理信息的规范性和安全性。     

Information extraction from case law and retrieval of prior cases

We describe an information extraction and retrieval system, called History Assistant, which extracts rulings from court opinions and retrieves relevant prior cases from a citator database. The technology employed is similar to that adopted in the Message Understanding Conferences, but attempts a fuller parse in order to distinguish current rulings from previous rulings reported in a case. In addition, we employ a combination of information retrieval and machine learning techniques to link each new case to related documents that it may impact. We present experimental results, in terms of precision and recall, for all tasks performed by the extraction and linking programs. Part of the finished system has been deemed worthy of further development into a computer-assisted database update tool to help editors assimilate historical relationships between cases into a concordance of court decisions, called a citator.     

Robust tube-based MPC for tracking of constrained linear systems with additive disturbances

This paper is devoted to solve the problem that the predictive controllers may present when the target operation point changes. Model predictive controllers (MPC) are capable to steer an uncertain system to a given target operation point fulfilling the constraints. But if the target changes significantly the controller may not success due to the loss of feasibility of the optimization problem and the inadequacy of the terminal conditions.This paper presents a novel formulation of a robust model predictive controller (MPC) for tracking changing targets based on a single optimization problem. The plant is assumed to be modelled as a linear system with additive uncertainties confined to a bounded known polyhedral set. Under mild assumptions, the proposed MPC is feasible under any change of the target and steers the uncertain system to (a neighborhood of) the target if this is admissible. If the target is not admissible, and hence unreachable, the system is steered to the closest admissible operating point.The controller formulation has some parameters which provide extra degrees of freedom. These new parameters allow control objectives such as disturbance rejection, output offset prioritization or enlargement of the domain of attraction to be dealt with. The paper shows how these parameters can be calculated off-line.In order to demonstrate the benefits of the proposed controller, it has been tested on a real plant: the four tanks plant which is a multivariable nonlinear system configured to exhibit non-minimum phase transmission zeros. Experimental results show the robust stability and offset-free tracking of the controlled plant.