Risk identification and safety assessment of human-computer interaction in integrated avionics based on STAMP

To solve the problem of risk identification and quantitative assessment for human-computer interaction(HCI)in complex avionics systems,an HCI safety analysis framework based on system-theoretical process analysis(STPA)and cognitive reliability and error analysis method(CREAM)is proposed.STPACREAM can identify unsafe control actions and find the causal path during the interaction of avionics systems and pilot with the help of formal verification tools automatically.The common performance conditions(CPC)of avionics systems in the aviation environment is established and a quantitative analysis of human failure is carried out.Taking the head-up display(HUD)system interaction process as an example,a case analysis is carried out,the layered safety control structure and formal model of the HUD interaction process are established.For the interactive behavior“Pilots approaching with HUD”,four unsafe control actions and35 causal scenarios are identified and the impact of common performance conditions at different levels on the pilot decision model are analyzed.The results show that HUD's HCI level gradually improves as the scores of CPC increase,and the quality of crew member cooperation and time sufficiency of the task is the key to its HCI.Through case analysis,it is shown that STPACREAM can quantitatively assess the hazards in HCI and identify the key factors that impact safety.

Hierarchical resource allocation for integrated modular avionics systems

Recently the integrated modular avionics （IMA） architecture which introduces the concept of resource partitioning becomes popular as an alternative to the traditional federated architecture. A novel hierarchical approach is proposed to solve the resource allocation problem for IMA systems in distributed environments. Firstly, the worst case response time of tasks with arbitrary deadlines is analyzed for the two-level scheduler. Then, the hierarchical resource allocation approach is presented in two levels. At the platform level, a task assignment algorithm based on genetic simulated annealing （GSA） is proposed to assign a set of pre-defined tasks to different processing nodes in the form of task groups, so that resources can be allocated as partitions and mapped to task groups. While yielding to all the resource con- straints, the algorithm tries to find an optimal task assignment with minimized communication costs and balanced work load. At the node level, partition parameters are optimized, so that the computational resource can be allocated further. An example is shown to illustrate the hierarchal resource allocation approach and manifest the validity. Simulation results comparing the performance of the proposed GSA with that of traditional genetic algorithms are presented in the context of task assignment in IMA systems.

Health management based on fusion prognostics for avionics systems

Health management permits the reliability of a system and plays a increasingly important role for achieving efficient system-level maintenance.It has been used for remaining useful life（RUL） prognostics of electronics-rich system including avionics.Prognostics and health management（PHM） have become highly desirable to provide avionics with system level health management.This paper presents a health management and fusion prognostic model for avionics system,combining three baseline prognostic approaches that are model-based,data-driven and knowledge-based approaches,and integrates merits as well as eliminates some limitations of each single approach to achieve fusion prognostics and improved prognostic performance of RUL estimation.A fusion model built upon an optimal linear combination forecast model is then utilized to fuse single prognostic algorithm representing the three baseline approaches correspondingly,and the presented case study shows that the fusion prognostics can provide RUL estimation more accurate and more robust than either algorithm alone.

Deploying Safety-Critical Applications on Complex Avionics Hardware Architectures

Aviation electronics (avionics) are sophisticated and distributed systems aboard an airplane. The complexity of these systems is constantly growing as an increasing amount of functionalities is realized in software. Thanks to the performance increase, a hardware unit must no longer be dedicated to a single system function. Multicore processors for example facilitate this trend as they are offering an increased system performance in a small power envelope. In avionics, several system functions could now be integrated on a single hardware unit, if all safety requirements are still satisfied. This approach allows for further optimizations of the system architecture and substantial reductions of the space, weight and power (SWaP) footprint, and thus increases the transportation capacity. However, the complexity found in current safety-critical systems requires an automated software deployment process in order to tap this potential for further SWaP reductions. This article used a realistic flight control system as an example to present a new model-based methodology to automate the software deployment process. This methodology is based on the correctness-by-construction principle and is implemented as part of a systems engineering toolset. Furthermore, metrics and optimization criteria are presented which further help in the automatic assessment and refinement of a generated deployment. A discussion regarding a tighter integration of this approach in the entire avionics systems engineering workflow concludes this article.

Intelligent Cost Modeling Based on Soft Computing for Avionics Systems

In parametric cost estimating, objections to using statistical Cost Estimating Relationships （CERs） and parametric models include problems of low statistical significance due to limited data points, biases in the underlying data, and lack of robustness. Soft Computing （SC） technologies are used for building intelligent cost models. The SC models are systemically evaluated based on their training and prediction of the historical cost data of airborne avionics systems. Results indicating the strengths and weakness of each model are presented. In general, the intelligent cost models have higher prediction precision, better data adaptability, and stronger self-learning capability than the regression CERs.

基于Vensim PLE的决策监管类系统的数据质量影响因素分析——以智能化国资国企在线监管平台系统为例

大数据时代,数据赋能和应用给政府和国有企业的决策和监管带来了便利,但决策监管类系统面临源数据获取、分析、处理等过程导致的数据质量不高问题,影响决策的精准性和监管的有效性。结合本人参与该平台建设需求分析和数据获取的实际工作过程,针对国有资产和国有企业数据获取到应用过程中影响数据质量的主要因素进行分析,构建了数据质量模型的因果关系图和流图,并通过Vensim PLE进行仿真实验,识别到人才对数据质量的重要性。同时,了解其中的学习培训时间、需求变更和元数据因素对数据质量的具体影响趋势,并提出对应改进数据质量的有效方法。

基于Vensim的汽车轻量化全生命周期动态评价

以往评价汽车产品的轻量化效果主要关注汽车的运行使用阶段,未能从整个汽车生命周期的各个阶段予以综合考虑,且评价模型仅是静态模型,加之国内的评价研究大多基于国外数据,得出的结论与中国实际情况差距较大。针对上述问题,应用系统动力学软件Vensim建立了基于中国数据的汽车产品轻量化全生命周期综合效益动态评价模型,对汽车产品轻量化(以材料轻量化为重点)对材料、能耗、排放及成本4个方面造成的影响进行动态评价与分析。动态评价模型涵盖汽车产品从材料获取、材料加工、零部件加工制造、整车装配、运行使用直至回收利用的生命周期全过程。选取某公司生产的传统汽油车和在此平台上开发的纯电动汽车作为实证研究对象,结果表明,考虑综合影响作用的铝镁轻量化,纯电动汽车各项评价指标均有不同程度的下降,而传统汽油车的全生命周期PM、CO排放及环境成本、人体健康损害影响(HTP)等反而有不同程度的升高;纯电动汽车的轻量化效果显著。

基于VENSIM的旅客综合运输模型

通过分析旅客运输方式与运输系统外部因素之间的关系,及经济、人口、基础设施建设等运输系统内部各种影响因素,运用系统动力学方法构建了旅客综合运输系统流图。采用效用理论分析了旅客出行方式选择机理,并运用Vensim软件构建了旅客综合运输系统分析模型。模拟结果表明:公路运输具有较高的运输效用,其次是铁路运输和航空运输;未来10 a内,铁路旅客运输效用将保持0.074%的年增长率,市场占有环比增长率为1.025%,航空旅客运输效用将保持0.182%的年增长率,市场占有环比增长率为4.282%。

A formal approach using SysML for capturing functional requirements in avionics domain

In this work,a Model-Based Systems Engineering approach based on Sys ML is proposed.This approach is used for the capture and the definition of functional requirements in avionics domain.The motivation of this work is triple:guide the capture of functional requirements,validate these functional requirements through functional simulation,and verify efficiently the consistency of these functional requirements.The proposed approach is decomposed into several steps that are detailed to go from conceptual model of avionics domain to a formal functional model that can be simulated in its operating context.To achieve this work,a subset of Sys ML has been used as an intermediate modelling language to ensure progressive transformation that can be understood and agreed by system stakeholders.Formal concepts are introduced to ensure theoretical consistency of the approach.In addition,transformation rules are defined and the mappings between concepts of ARP4754 A civil aircraft guidelines and Sys ML are formalized through meta-model.The resulting formalization enables engineers to perform functional simulation of the top-level functional architecture extracted from operational scenarios.Finally,the approach has been tested on an industrial avionics system called the Onboard Maintenance System.

Hybrid partition-and network-level scheduling design for distributed integrated modular avionics systems

Distributed Integrated Modular Avionics(DIMA)develops from Integrated Modular Avionics(IMA)and realizes distributed integration of multiple sub-function areas.Timetriggered network provides effective support for time synchronization and information coordination in DIMA systems.However,inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism.To ensure such time determinism and achieve guaranteed real-time performance,system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain.This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication,and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes.Furthermore,incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost.To control such cost,this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible.Finally,two typical cases,including a simple fully connected DIMA system case and an industrial DIMA system case,are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.

Performability analysis of avionics system with multilayer HM/FM using stochastic Petri nets

The integrated modular avionics （IMA） architecture is an open standard in avionics industry, in which the number of functionalities implemented by software is greater than ever before. In the IMA architecture, the reliability of the avionics system is highly affected by the software applications. In order to enhance the fault tolerance feature with regard to software application failures, many industrial standards propose a layered health monitoring/fault management （HM/FM） scheme to periodically check the health status of software application processes and recover the malfunctioning software process whenever an error is located. In this paper, we make an analytical study of the HM/FM system for avionics application software. We use the stochastic Petri nets （SPN） to build a formal model of each component and present a method to combine the components together to form a complete system model with respect to three interlayer query strategies. We further investigate the effectiveness of these strategies in an illustrative system.

基于Vensim的装备保障力量仿真分析

装备保障力量体系是装备保障系统的重要组成部分,现阶段我军存在着装备保障力量层次分布不合理、装备保障力量编配不科学等问题。针对上述问题,基于系统动力学,从战略、战役、战术的总体角度出发,分析了装备保障力量构成要素的总体因果关系,并在Vensim中对装备保障力量进行了建模仿真。根据仿真结果,给出了装备保障力量层次结构优化建议。

A critique of reliability prediction techniques for avionics applications

Avionics （aeronautics and aerospace） industries must rely on components and systems of demonstrated high reliability. For this, handbook-based methods have been traditionally used to design for reliability, develop test plans, and define maintenance requirements and sustainment logistics, However, these methods have been criticized as flawed and leading to inaccurate and mis- leading results. In its recent report on enhancing defense system reliability, the U.S. National Academy of Sciences has recently discredited these methods, judging the Military Handbook （MIL- HDBK-217） and its progeny as invalid and inaccurate. This paper discusses the issues that arise with the use of handbook-based methods in commercial and military avionics applications. Alter- native approaches to reliability design （and its demonstration） are also discussed, including similarity analysis, testing, physics-of-failure, and data analytics for prognostics and systems health management.

基于Vensim的供应链牛鞭效应研究

为了研究Y企业供应链产生牛鞭效应的内部因素,基于系统动力学及Vensim软件进行仿真分析,构建Y企业供应链模型及系统动力学方程,绘制供应链系统的因果关系图及系统流图。根据Y企业调研情况,确定系统动力学模型的仿真初值及其中参数,分析各参数对于系统牛鞭效应的影响大小。引入表征牛鞭效应大小的指标NX,通过计算得到改善前后NX的变化率,即改善后牛鞭效应弱化率,为企业未来选择优先改善方向和安排改善先后顺序等提供参考。

Thermal models for avionics pod cabin based on Stochastic Configuration Network(SCN)

The thermal failure of airborne avionics equipment is not optimistic.It is very necessary to establish relatively accurate thermal models for predicting thermal response of avionics equipment under different flight conditions.Traditional thermal modeling methods are often difficult to obtain accurate temperature response in complex conditions.This has severely restricted the application of these models.However,the Stochastic Configuration Network(SCN)model based on random algorithm can weaken the heat transfer mechanism and pay attention to the mining of experimental data,so that a more accurate thermal relationship might be obtained.In this paper,the SCN was used to analyze the experimental data of the avionics pod with a Ram Air Turbine(RAT)cooling system.The thermal models based on the SCN were finally built for avionics pod.Compared with the commonly used Random Vector Functional Link Network(RVFLN)thermal models,the SCN thermal models not only inherit the advantages of simple network structure and low computational complexity,but also have some merits,such as the better learning performance and the less human intervention.The presented SCN models provide a way to predict the thermal response of avionics pod cabin under the full flight envelope for a fighter.

基于Vensim模型的高校中水回用系统模拟预测

文章以内蒙古呼和浩特市某高校分散式中水回用系统为研究对象,以系统动力学原理为理论指导,利用系统动力学软件,通过研究该高校各项用水因素之间的相互作用和联系,建立中水回用Vensim模型,分析影响中水使用量的主要因素,预测学校未来20年内中水用需水情况。

基于Vensim的集群式供应链跨链库存应急合作

运用系统动力学方法,针对由两条单链多环节组成的集群式供应链,应用Vensim建模软件,建立基于竞合条件的集群式供应链跨链库存应急补充模型。通过Vensim模拟的结果,对跨链库存应急补充模型进行参数灵敏度分析和指标检验分析,结果表明,库存应急补充可以在库存不大量增加的前提下有效提高供应链的市场需求满足率。

基于Vensim的存货控制系统动力学模拟

本文针对存货控制管理中存在的问题,引入系统动力学仿真模型进行研究,并以一个简单的存货控制案例,首先采用Excel进行分析,进而应用SD专业软件Vensim进行仿真,最后对Excel与Vensim进行比较,为财务人员研究存货控制提供了一个新的路径。

基于Vensim的物流网络库存优化仿真分析

在复杂的物流供应链网络中,上下游多个环节之间的库存,存在一定的关系。为优化物流系统网络,揭示生产商、转运中心、配送中心之间的库存关系,文中以Vensim为工具,建立了仿真模型。分析了库存调整时间、延迟时间和客户需求的变化对各级库存的影响关系,进而提出了库存优化的思路,可为物流网络优化提供一定的参考。

基于改进的Vensim模型模拟岩溶泉水文过程

经典的Vensim模型采用2个平行线性水箱来模拟岩溶水文系统中的慢速流和快速流,很难模拟岩溶水文系统内的非线性水文过程。提出一种改进的R-Vensim模型,将Vensim中的一个水箱改为非线性水箱,同时进一步考虑不同水文条件下降雨分配系数的变化,用于模拟岩溶含水层中存在的非线性水文过程。2个模型被用于模拟丫吉试验场的S31岩溶泉,模拟结果表明R-Vensim能更好地模拟不同降雨条件下岩溶泉水文动态过程,而Vensim总是低估暴雨下的流量峰值和高估低强度降雨下的流量峰值。研究区岩溶水文系统中慢速流呈现强烈的非线性,而快速流更接近于线性过程,2个模拟时段内78.5%和68.4%的泉流量来源于非线性水箱。研究结果表明模型中考虑非线性水文过程对于岩溶泉流量尤其低流量过程的精准模拟十分重要。