Search

With the rise in cloud computing architecture, the development of service-oriented simulation models has gradually become a prominent topic in the field of complex system simulation. In order to support the distributed sharing of the simulation models with large computational requirements and to select the optimal service model to construct complex system simulation applications, this paper proposes a service-oriented model encapsulation and selection method. This method encapsulates models into shared simulation services, supports the distributed scheduling of model services in the network, and designs a semantic search framework which can support users in searching models according to model correlation. An optimization selection algorithm based on quality of service (QoS) is proposed to support users in customizing the weights of QoS indices and obtaining the ordered candidate model set by weighted comparison. The experimental results showed that the parallel operation of service models can effectively improve the execution efficiency of complex system simulation applications, and the performance was increased by 19.76% compared with that of scatter distribution strategy. The QoS weighted model selection method based on semantic search can support the effective search and selection of simulation models in the cloud environment according to the user&rsquo, s preferences.

The monitoring and warning system of main agro-meteorological disasters in Zhejiang Province is researched and developed herein based on technology of WebGIS. According to SOA and B/S structure, the system is constructed on ASP.NET development platform by using C# and Java computer language, and applied in in Zhejiang Meteorological Department as a subsystem of “Zhejiang Modern Agricultural Meteorology Business System”.

In critical applications such as civil aviation and signal control in railway traffic, very high reliability of computer control systems is required. So the dissimilar redundancy technique must be adopted in those systems to replace the similar redundancy technique. Similar redundancy can effectively avoid the noncommon stochastic failures that appear in systems, but for common faults such as errors in hardware design and software coding, it would ruin the whole system. In this paper, we introduce a dissimilar fault-tolerant control computer system with software and hardware in detail. A tool SHDFTA (Software/Hardware Dynamic Fault Tree Analysis) 1.0 combining a reliability analysis methodology-Dynamic Fault Tree Analysis (DFTA) is applied to evaluate the system and illustrate the new reliability brought by the dissimilar redundant technique, and the algorithm of DFTA is also introduced.

Modern control systems are mostly composed of hardware and software, the performance of which is affected by their hardware and software. Therefore, when analyzing the system's reliability, the effect of the hardware, software and their interaction must be considered. In this paper, we study the reliability analysis of the triplex electronic-hydraulic servo actuator system with a combination of FMECA and FTA. This method is partly based on the knowledge database, that is, some of the FMECA information comes from the knowledge database, and some of that comes from the analyzers. When the FMECA information of the system is enough, the subtrees of the system's typical components can be constructed with the aid of the computer, and that will help the analyzers finish the construction of the system's entire fault tree.

Digital Fly-By-Wire (FBW) Flight Control System (FCS) is designed to achieve high level of reliability, frequently employ high level of redundancy. Dynamic redundancy employed in FEW system can realize complex fault and error diagnosis, recovery and reconfiguration. It is very difficult to analyze the reliability of the FEW system by traditional methods, such as Fault Tree Analysis (FTA) or Network Analysis. This paper describes dynamic fault-tree modeling techniques for handling these difficulties and provides a Markov Chain generation modeling method for coverting Dynamic Fault Tree to Markov Chain. The software failure of the FBW system can also be considered in the model. An example of a quadruple FEW redundant system and a Markov State Transition Chain software package (MSTCP) are given.

Modern digital avionics system consist of hardware subsystem and software subsystem, in which there are some characteristics: interaction, real time and so on. In this paper, several combined HW/SW system reliability models published are summarized. A new combined HW/SW system growth model based on Markov processes is presented. How to solve the problem of reliability growth for both hardware and software during the development phase is described. This model could be applied to predict and evaluate the reliability and availability for combined HW/SW computer control system. >

This paper describes a method of function reconfiguration, dealing with the failure of helm control. When a helm of the aircraft fails, how to reconfigure the remaining normal helms to balance the aircraft again is an important problem. This paper introduces a method to solve this problem, and simulates the airplane with a computer. In the Fly-By-Wire flight control system, we can instigate a contol mixer which reassigns the control to helms, with regard to the control law and the actuator. Normally, it is an identification matrix; when a failure occurs, an algorithm is used to calculate the matrix, so that the control law has the same effect as the state before failure. There are two algorithms for two fail modes of the helm: turn to middle and lock. As an illustration example, the function reconfiguration method is exercised on an airplane, it is shown that with the helm turning to middle failure mode, the effect of using the reconfiguration algorithm is satisfactory. In addition it is also shown via simulation that with the lock failure mode, the use of this reconfiguration method is feasible when the failed helm locks within the limited angle.