Applying Evolutionary Computing to Complex Systems Design

Development of an evolutionary computing tool for requirements analysis and optimization of component-based systems is described. The tool assesses scenarios that represent potential designs and their operational behavior, as well as how the designs perform in a range of environmental conditions. Designs are optimized for three objective functions: 1) reliability; 2) performance time; and 3) costs. Use of the tool is illustrated in a systems engineering case study to derive optimal design for a naval command and control system that includes human operator roles as well as technology components.     

Scenario-based assessment of nonfunctional requirements

This paper describes a method and a tool for validating nonfunctional requirements in complex socio-technical systems. The system requirements analyzer (SRA) tool validates system reliability and operational performance requirements using scenario-based testing. Scenarios are transformed into sequences of task steps and the reliability of human agents performing tasks with computerized technology is assessed using Bayesian belief network (BN) models. The tool tests system performance within an envelope of environmental variations and reports the number of tests that pass a benchmark threshold. The tool diagnoses problematic areas in scenarios representing pathways through system models, assists in the identification of their causes, and supports comparison of alternative requirements specifications and system designs. It is suitable for testing socio-technical systems where operational scenarios are sequential and deterministic, in domains where designs are incrementally modified so set up costs of the BNs can be defrayed over multiple tests.     

基于CAS理论的智能指控系统防空作战效能评估仿真研究

防空作战指挥控制模型复杂,为评估分析智能指控系统对防空作战效果的影响,本文从战场全局出发,对作战要素进行简化,将作战双方分为攻守两方,作战要素分为：进袭飞机、指控系统和地空导弹等三类作战主体Agent。通过NetLog04．0软件对防空作战系统进行仿真实验,分析了在其它作战条件一定的情况下,指控系统智能化水平高低对现代防空作战效果的影响。     

Switching control for thruster-assisted position mooring

The position mooring (PM) for marine vessels contains several controllers, such as heading, damping, restoring and mean force controllers which could be activated or deactivated depending on the environmental and operational conditions. This paper proposes to integrate these controllers into a switching control system. The supervisory control is adopted to facilitate the automatic switching. The supervisory switching control involves the designs of a set of models to track the existing operational condition and the switching logic. Simulations and experiments will be provided for validation. It is shown that the switching control could extend the weather window of the PM system.     

The system reliability analyser tool

This paper describes the design and evaluation of a socio-technical design support system, the system reliability analyser (SRA). The tool is used to validate non-functional system requirements, such as system reliability. It employs a Bayesian belief network (BBN) model to assess system reliability (Pearl in Probabilistic reasoning in intelligent systems: networks of plausible information, 1988) based on a variety of high-level operational scenarios. The tool diagnoses problematic areas in future system models and assists in the identification of their causes. The evaluation of the tool demonstrated that it supported the task it was intended to do. The evaluation also identified usability problems in the current visualisations and illustrated their resolution.     

自行火炮系统作战效能建模与仿真研究

在综合研究国内外效能评估理论和方法的基础上,根据多年来自行火炮发展建设和作战运用的实际需求,建立了对抗条件下战斗、保障、指挥控制等分系统的作战效能及作战系统评估模型。依据可靠性、维修性数字仿真的基本理论,利用Monte—Carlo方法对某型自行火炮战场对抗阶段进行仿真,可以实现自行火炮可靠性、维修性及系统作战效能的动态评估。该方法受评估者的主观性影响较小,为系统效能的动态评估系统的设计构想提出了评估思路。该模型可以为自行火炮系统的方案论证、工程研制、鉴定定型和作战运用等提供决策依据。     

Software Fault Tolerance: An Evaluation

In order to assess the effectiveness of software fault tolerance techniques for enhancing the reliability of practical systems, a major experimental project has been conducted at the University of Newcastle upon Tyne. Techniques were developed for, and applied to, a realistic implementation of a real-time system (a naval command and control system). Reliability data were collected by operating this system in a simulated tactical environment for a variety of action scenarios. This paper provides an overview of the project and presents the results of three phases of experimentation. An analysis of these results shows that use of the software fault tolerance approach yielded a substantial improvement in the reliability of the command and control system.     

Police command and control system

Following the experimental computerized command and control system used in Birmingham, UK, the West Midlands police are introducing an operational system to cover the whole of the West Midlands. This paper describes the applications available on the system, and stresses the reliability and recovery aspects in particular.     

Risk assessment modelling of microbiology-related solids separation problems in activated sludge systems

This paper proposes a risk assessment model for settling problems of microbiological origin in activated sludge systems (filamentous bulking, foaming and rising sludge). The aim of the model is not to diagnose microbiology-related solids separation problems with absolute certainty but to quantify in dynamic scenarios whether simulated operational procedures and control strategies lead to favourable conditions for them to arise or not. The rationale behind the model (which integrates the mechanisms of standard activated sludge models with empirical knowledge), its implementation in a fuzzy rule-based system and the details of its operation are illustrated in the different sections of the paper. The performance of the risk assessment model is illustrated by evaluating a number of control strategies facing different short-term influent conditions as well as long-term variability using the IWA/COST simulation benchmark. The results demonstrate that some control strategies, although performing better regarding operating costs and effluent quality, induce a higher risk for solids separation problems. In view of these results, it is suggested to integrate empirical knowledge into mechanistic models to increase reliability and to allow assessment of potential side-effects when simulating complex processes.     

基于OSGI的软构件实时数据处理子系统设计与实现

实时数据处理子系统是试验指挥控制系统的重要组成部分。基于软构件技术对其进行设计并部分实现,为今后试验指挥控制系统跨平台开发和使用提供了可行的技术方案和实施途径。     

Reliability-based design optimization of aeroelastic structures

Aeroelastic phenomena are most often either ignored or roughly approximated when uncertainties are considered in the design optimization process of structures subject to aerodynamic loading, affecting the quality of the optimization results. Therefore, a design methodology is proposed that combines reliability-based design optimization and high-fidelity aeroelastic simulations for the analysis and design of aeroelastic structures. To account for uncertainties in design and operating conditions, a first-order reliability method (FORM) is employed to approximate the system reliability. To limit model uncertainties while accounting for the effects of given uncertainties, a high-fidelity nonlinear aeroelastic simulation method is used. The structure is modelled by a finite element method, and the aerodynamic loads are predicted by a finite volume discretization of a nonlinear Euler flow. The usefulness of the employed reliability analysis in both describing the effects of uncertainties on a particular design and as a design tool in the optimization process is illustrated. Though computationally more expensive than a deterministic optimum, due to the necessity of solving additional optimization problems for reliability analysis within each step of the broader design optimization procedure, a reliability-based optimum is shown to be an improved design. Conventional deterministic aeroelastic tailoring, which exploits the aeroelastic nature of the structure to enhance performance, is shown to often produce designs that are sensitive to variations in system or operational parameters.     

基于一体化指挥平台的防空指控系统软件体系结构

基于一体化指挥平台的防空指挥系统软件由防空专用软件和一体化指挥平台软件组成,实现对上与联指的互联互通,对下与下级作战群(分)队的指挥控制.阐述防空指挥控制系统软件与一体化指挥平台的关系,采用分层的思想对防空指挥系统软件体系结构进行研究.     

A deep learning-enhanced Digital Twin framework for improving safety and reliability in human–robot collaborative manufacturing

In Industry 5.0, Digital Twins bring in flexibility and efficiency for smart manufacturing. Recently, the success of artificial intelligence techniques such as deep learning has led to their adoption in manufacturing and especially in human–robot collaboration. Collaborative manufacturing tasks involving human operators and robots pose significant safety and reliability concerns. In response to these concerns, a deep learning-enhanced Digital Twin framework is introduced through which human operators and robots can be detected and their actions can be classified during the manufacturing process, enabling autonomous decision making by the robot control system. Developed using Unreal Engine 4, our Digital Twin framework complies with the Robotics Operating System specification, and supports synchronous control and communication between the Digital Twin and the physical system. In our framework, a fully-supervised detector based on a faster region-based convolutional neural network is firstly trained on synthetic data generated by the Digital Twin, and then tested on the physical system to demonstrate the effectiveness of the proposed Digital Twin-based framework. To ensure safety and reliability, a semi-supervised detector is further designed to bridge the gap between the twin system and the physical system, and improved performance is achieved by the semi-supervised detector compared to the fully-supervised detector that is simply trained on either synthetic data or real data. The evaluation of the framework in multiple scenarios in which human operators collaborate with a Universal Robot 10 shows that it can accurately detect the human and robot, and classify their actions under a variety of conditions. The data from this evaluation have been made publicly available, and can be widely used for research and operational purposes. Additionally, a semi-automated annotation tool from the Digital Twin framework is published to benefit the collaborative robotics community.     

一种新型的作战指挥流程效能评估模型

为建立作战指挥流程效能的评估模型,定义在某一种指挥流程下,指挥信息传递过程中信息流通迅速程度的度量称为指挥流的“时效”,以“时效”的大小作为衡量流程效能的高低。“反馈”是作战指挥流程中常见的情况,根据实际情况确立了“反馈”流程的非线性反馈函数。此方法为优化指挥流程提供了一种科学有效的定量分析途径。     

指控软件可靠性评估方法研究

以指控软件为对象,讨论了研究指控软件在操作剖面不确定性时可靠性评估的必要性。并针对分域测试情况,建立了指控软件在不确定操作剖面下的可靠性评估模型。在典型剖面下,当测试结果无失效时,利用序法求解软件可靠度的精确置信限。最后通过实例将本文方法得到的结果与使用文献[7]中方法得到的结果进行比较,本文方法得到可靠度评估值要高。     

柔性长鳍波动推进仿生水下机器人控制系统设计与实现

论文以基于柔性长鳍波动推进的仿生水下机器人试验模型为背景,主要研究其控制系统总体结构、硬件和软件的设计与实现问题。控制系统设计为主从结构,主从模块间通过CAN总线进行通讯。主控模块采用遥控与程控两种工作模式,并通过遥控指令实现模式切换。试验模型的推进、俯仰与转向控制由仿生柔性长鳍、重心调节模块和2自由度“十”字形尾舵3个控制子模块实现,各控制子模块设计为闭环伺服控制系统。系统综合测试和试验模型航行试验结果表明,论文设计实现的控制系统主从模块间通讯顺畅,功能协调,性能可靠,实现了设计功能并达到了预期的目标。     

高可靠的计算机模块引导软件

在航天软件领域,为适应相关软件的快速发展与迭代,需要一种引导软件,使其能够对不同应用程序进行重构并保证其高可靠性. 本文基于SPARC架构设计并实现了一种引导软件,该引导软件既可以根据引导标识自动引导某个程序,又可以在地面指令控制下进行应用程序重构、引导等. 同时,采用三冗余架构、反弹墙、EDAC保护等可靠性措施,确保运行过程中的大多数软件错误能够得到恢复. 最终在计算机模块上进行测试,测试结果达到了预期目的.     

基于Nios的温备份智能容错系统的设计

本文是在充分研究了智能故障诊断、容错控制以及可靠性理论的前提下,运用FPGA、Nios处理器、控制理论、人工智能等相关知识,提出了一个能在实际的网络系统中提高服务器运行可靠性的有效方法——温备份智能容错系统。该方法使用Nios软核处理器以及FPGA的优点,运用SOPC Builder工具设计了一个智能仲裁器的核心部件。该仲裁器能够智能地获取服务器的状态、同步服务器的内容以及控制服务器的开启和关闭。从而提高了系统的可靠性,延长了服务器的使用寿命。本文给出了该方法的实现模型及详细实现步骤。     

Calibration-based tool condition monitoring for repetitive machining operations

Reliable tool condition monitoring (TCM) system is essential for any machining process in mass production to control the part quality as well as reduce the machine tool downtime and maintenance costs. However, while various research studies have proposed their TCM systems, the complexity in setups with advanced decision-making algorithms and specificity in application to limited cutting conditions continue to complicate the implementation of these systems into practical scenarios. This study develops a very simple and flexible TCM system for repetitive machining operations. The proposed monitoring approach reduces the complexity of monitoring model by considering the important characteristic of repeatability in process which has been commonly found in the mass production scenario and implements the calibration procedure to improve the flexibility of the model application to actual machining processes with complex toolpath designs and variable cutting conditions. The selected cutting tools with specific tool conditions are used in the calibration phase to generate reference signals. In actual repetitive production, the collected signal generated by the cutting tool in each operation is compared with reference signals to identify the most similar condition of the reference tool through the proposed similarity analysis. To validate the performance, the current study demonstrates the application of proposed monitoring approach to monitor the tool wear in repetitive milling operations with complex toolpath, and the predicted tool wear progression is found to be in good agreement with experimental measurements during the machining of multiple parts over the entire tool life.