Assessment of Dependent Performance Shaping Factors in SPAR-H Based on Pearson Correlation Coefficient

With the improvement of equipment reliability,human factors have become the most uncertain part in the system.The standardized Plant Analysis of Risk-Human Reliability Analysis(SPAR-H)method is a reliable method in the field of human reliability analysis(HRA)to evaluate human reliability and assess risk in large complex systems.However,the classical SPAR-H method does not consider the dependencies among performance shaping factors(PSFs),whichmay cause overestimation or underestimation of the risk of the actual situation.To address this issue,this paper proposes a new method to deal with the dependencies among PSFs in SPAR-H based on the Pearson correlation coefficient.First,the dependence between every two PSFs is measured by the Pearson correlation coefficient.Second,the weights of the PSFs are obtained by considering the total dependence degree.Finally,PSFs’multipliers are modified based on the weights of corresponding PSFs,and then used in the calculating of human error probability(HEP).A case study is used to illustrate the procedure and effectiveness of the proposed method.

Impactof Device Architecture on Performance and Reliability of Deep Submicron SOI MOSFETs( invited paper)

The main electrical properties of advanced Silicon On Insulator MOSFETs are addressed. The subthreshold and high field operations are analysed as a function of device architecture. The special SOI parasitic phenomena, such as the floating body potential and temperature, are critically reviewed. The main limitations of submicron MOSFET are comparatively evaluated for various SOI structures. Short channel and hot carrier effects as well as the reliability of the SOI technology are investigated for gate length down to sub\|0 1 micron.

Structural Reliability Analysis for Implicit Performance with Legendre Orthogonal Neural Network Method

In order to evaluate the failure probability of a complicated structure,the structural responses usually need to be estimated by some numerical analysis methods such as finite element method( FEM). The response surface method( RSM) can be used to reduce the computational effort required for reliability analysis when the performance functions are implicit. However,the conventional RSM is time-consuming or cumbersome if the number of random variables is large. This paper proposes a Legendre orthogonal neural network( LONN)-based RSM to estimate the structural reliability. In this method,the relationship between the random variables and structural responses is established by a LONN model. Then the LONN model is connected to a reliability analysis method,i.e. first-order reliability methods( FORM) to calculate the failure probability of the structure.Numerical examples show that the proposed approach is applicable to structural reliability analysis,as well as the structure with implicit performance functions.

Role of Software Reliability Models in Performance Improvement and Management

Software reliability models describe the failure behavior of the software. The models are used to evaluate the software quantitatively. They assess the reliability of the software by predicting faults or failures for a software. Reliability is one of important quality attributes of the software in which software end user is more interested rather than the software developer. Hence, the performance of a software can be improved by incorporating important quality attributes like reliability, maintainability and availability of the software along with performance attributes like response time and throughput. The paper discusses about the role played by important software reliability models in analyzing the failure prediction of the software. It also explores the strong relationship that exists between quality attributes and performance attributes. With some illustrations highlighting the necessity of in-depth understanding of the link that exists between reliability and performance of the software. The derived knowledge helps in improving the performance of the software sustainably over a period of time and manage the software more effectively.

An Overview of Performance Characteristics, Experiencesand Trends of Aerospace Engine Bearings Technologies

In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today＇s material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH ＆ Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.

Future Performance Prediction of Research Infrastructure Based on Past Performance

Research infrastructure is crucial for development of research,and thus the evaluation of its performance is important.However,existing researches mostly focus on its past observations,lacking of a prediction for future. In this paper, procedures are proposed to predict the distribution for the number of papers published in a certain future year. The publication reliability,which is defined as the probability that the number of published papers in the future year is bigger than a pre-specified number,is evaluated. Illustrative examples are proposed to show the applications of the model.

Design of Eco-friendly Ultra-high Performance Concrete with Supplementary Cementitious Materials and Coarse Aggregate

Aiming to investigate the mix design of eco-friendly UHPC with supplementary cementitious materials and coarser aggregates, we comprehensively studied the workability, microstructure, porosity, compressive strength, flexural strength, and Young’s modulus of UHPC. Relationship between compressive strength and Young’s modulus was obtained eventually. It is found that the compressive strength, flexural strength, and Young’s modulus of UHPC increase by 19.01%, 10.81%, and 5.99%, respectively, when 40 wt% cement is replaced with supplementary cementitious materials. The relationship between compressive strength and Young’s modulus of UHPC is an exponential form.

Computational Analysis of Performance for Heterogeneous Integrated System with Test Automation

Heterogeneity is inevitable in enterprises due to their various input requirements. The usage of proprietary integration products results in the increased cost of enterprises. During the integration, the focus area has been found to often address only the functional requirements, while the non-functional requirements are side-stepped during the initial stages of a project. Moreover, the use of proprietary integration products and non-standards-based integration platform has given rise to an inflexible integration infrastructure resulting in adaptability concerns. Web services-based integration, based on open standards, is deemed to be the only feasible solution in such cases. This paper explains the performance analysis of enterprise integration in heterogeneous environments for the distributed and the transactional applications. The analysis presented in this paper is seen as a step towards making intelligent decisions well in advance when choosing the integration mechanism/products to address the functional as well as the non-functional requirements considering the future integration needs.

Load Dependent Series-Parallel Systems with Common Bus Performance Sharing Mechanism

A series-parallel system was proposed with common bus performance sharing in which the performance and failure rate of the element depended on the load it was carrying. In such a system,the surplus performance of a sub-system can be transmitted to other deficient sub-systems. The transmission capacity of the common bus performance sharing mechanism is a random variable. Effects of load on element performance and failure rate were considered in this paper. A reliability evaluation algorithm based on the universal generating function technique was suggested. Numerical experiments were conducted to illustrate the algorithm.

Characteristics of Integrated Importance Measure for Whole Lifetime-Oriented System Performance Evaluation

Importance measures are being widely used to characterize the importance of component in systems.Focus on the integrated importance measure(IIM)of the whole lifetime measure based on the transition rates of component states.To describe the impact of each component in whole lifetime,the IIM is generalized in nonrepairable and repairable systems at first.Then,their formulas are computed in series and parallel systems.Finally,the characteristics of generalized IIM in typical series systems and parallel systems are analyzed.The results show that the generalized IIM of component can evaluate the expected effect of component state on the system performance in whole lifetime.

Bayesian estimator of human error probability based on human performance data

A Bayesian method for estimating human error probability（HEP） is presented.The main idea of the method is incorporating human performance data into the HEP estimation process.By integrating human performance data and prior information about human performance together,a more accurate and specific HEP estimation can be achieved.For the time-unrelated task without rigorous time restriction,the HEP estimated by the common-used human reliability analysis（HRA） methods or expert judgments is collected as the source of prior information.And for the time-related task with rigorous time restriction,the human error is expressed as non-response making.Therefore,HEP is the time curve of non-response probability（NRP）.The prior information is collected from system safety and reliability specifications or by expert judgments.The（joint） posterior distribution of HEP or NRP-related parameter（s） is constructed after prior information has been collected.Based on the posterior distribution,the point or interval estimation of HEP/NRP is obtained.Two illustrative examples are introduced to demonstrate the practicality of the aforementioned approach.

The Performance Analysis of Multi-Layer Split-Protocol

The growing need for high-performance networking is achieved with parallel processing;several networking functions are processed concurrently in order to accomplish a performance Networking Architecture. Open systems interconnection (OSI) model is an example of multi-layering structure, and each layer performs definite function unique to that layer. OSI model works on pass it on principle, and it is divided in two stacks lower stack and upper stack. Layers 4 - 7 represent upper stack and responsible for data applications. The remaining 1 - 3 layers represent the lower stack and mostly involve in data movement. There are many techniques are available for server optimization enhancing the availability by distributing the load among peer servers. According to our knowledge, nobody has implemented such splitting architecture across the entire OSI model. In this paper, we present multilayer Split-protocol (MLSP) a high performance, reliable and secure technique for spiting an application or network protocol across OSI model, and we present the design, implementation, and empirical performance evaluation of MLSP. It is the ideal choice for Cloud services where each functional component is considered an independent of each other.

Influence of Velocity Overshoot Effect on High Frequency Perform- ance of AlGaAs / GaAs HBT's

The semiclassical transport equations are used to study the high frequency performance of AlGaAs / GaAs HBTs. Electron velocity overshoot effect and its influence on the cut off frequency characteristics of AlGaAs / GaAs HBTs with different collector design parameters are analyzed and discussed.

Integrated importance measure for multi-state coherent systems of k level

To verify the effectiveness of the integrated importance measure （IIM） for multi-state coherent systems of k level, the definition and physical meaning of IIM are demonstrated. Then, the improvement potential and Δ-importance measures are generalized to multi-state coherent systems based on the system performance level, and the relationships between IIM and traditional importance measures are discussed. The characteristics of IIM are demonstrated in both series and parallel systems. Also, an application to an oil transportation system is given. The comparison results show that： （i） IIM has some useful properties that are not possessed by traditional importance measures; （ii） IIM is effective in evaluating the component role in multi-state systems when the component reliability and the failure rate are simultaneously considered.

Expected Sliding Distance of Vertical Slit Caisson Breakwater

Evaluating the expected sliding distance of a vertical slit caisson breakwater is proposed. Time history for the wave load to a vertical slit caisson is made. It consists of two impulsive wave pressures followed by a smooth sinusoidal pressure. In the numerical analysis, the sliding distance for an attack of single wave was shown and the expected sliding distance during 50 years was also presented. Those results were compared with a vertical front caisson breakwater without slit. It was concluded that the sliding distance of a vertical slit caisson may be over-estimated if the wave pressure on the caisson is evaluated without considering vertical slit.

An Uncertainty Analysis and Reliability-Based Multidisciplinary Design Optimization Method Using Fourth-Moment Saddlepoint Approximation

In uncertainty analysis and reliability-based multidisciplinary design and optimization(RBMDO)of engineering structures,the saddlepoint approximation(SA)method can be utilized to enhance the accuracy and efficiency of reliability evaluation.However,the random variables involved in SA should be easy to handle.Additionally,the corresponding saddlepoint equation should not be complicated.Both of them limit the application of SA for engineering problems.The moment method can construct an approximate cumulative distribution function of the performance function based on the first few statistical moments.However,the traditional moment matching method is not very accurate generally.In order to take advantage of the SA method and the moment matching method to enhance the efficiency of design and optimization,a fourth-moment saddlepoint approximation(FMSA)method is introduced into RBMDO.In FMSA,the approximate cumulative generating functions are constructed based on the first four moments of the limit state function.The probability density function and cumulative distribution function are estimated based on this approximate cumulative generating function.Furthermore,the FMSA method is introduced and combined into RBMDO within the framework of sequence optimization and reliability assessment,which is based on the performance measure approach strategy.Two engineering examples are introduced to verify the effectiveness of proposed method.

基于冲击的涡扇发动机退化建模与下发预测

为解决多性能参数模型无法描述不同起飞推力下发动机性能退化的问题,利用单性能参数结合极端冲击模型描述起飞时发动机全功率运转对热端部件的热冲击影响,利用线性退化模型描述发动机自然退化过程,建立发动机性能可靠度退化模型。利用V2500发动机全寿命EGTM数据,结合最大似然估计给出性能可靠度表达式与模型参数,最后利用机队中同型V2500发动机非完整EGTM数据验证模型,预测下发时间,结果表明此模型预测下发时间和实际下发时间的误差小于3%,证明了模型的有效性。

腐蚀作用下城市轨道车辆齿轮磨损可靠性研究

为解决城市轨道车辆齿轮在腐蚀性环境下的磨损可靠性预测问题,采用非齐次泊松过程和对数高斯分布表征齿面腐蚀坑的萌生和生长,并考虑磨损对腐蚀坑深度的改变,通过分析腐蚀坑对赫兹接触应力、齿面粗糙度的影响,基于Archard磨损理论,以齿面最大累积磨损深度为关键参数建立性能裕量退化模型,构建出一种腐蚀作用下的城市轨道车辆齿轮磨损可靠性分析模型,并对腐蚀过程涉及的参数进行可靠性灵敏度分析。结果表明:随着工作时间的增长,齿轮累积磨损量的不确定性增加,腐蚀对齿轮磨损可靠性的影响程度降低;腐蚀坑生长过程的比例参数、形状参数和最大腐蚀深度对可靠性的灵敏度依次增加,且均与齿轮磨损可靠寿命呈负相关关系。

基于边缘计算的船舶大型主动隔振系统分布式控制架构

[目的]旨在解决现有主动隔振系统集中式控制架构可靠性低、抗风险能力弱、实时性低的问题,结合隔振系统与边缘计算研究现状,设计一种基于边缘计算的船舶大型主动隔振系统分布式控制架构。[方法]首先,分析集中式与分布式控制方法的特点;然后,对控制系统整体架构进行研究,设计系统的层次结构与整体架构,将其划分为云、边和端3个层次,并详述各层的架构设计与联系;最后,设计实验平台,通过实验测试系统的可靠性和实时性。[结果]结果表明,所设计的系统架构在突发状况下依然正常运行、稳定可靠,可将时钟同步偏差缩小到1μs,提高了系统实时性。[结论]该系统架构设计合理、高效,可有效提升隔振系统的可靠性、抗风险能力和实时性。