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Useful life prediction using a stochastic hybrid automata model for an ACS multi-gyro subsystem

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Journal of Systems Engineering and Electronics 2019年第1期30卷 154-166页

作者： CHENG Yuehua JIANG Liang JIANG Bin LU Ningyun College of Astronautics Engineering Nanjing University of Aeronautics and Astronautics College of Automation Engineering Nanjing University of Aeronautics and Astronautics

A useful life prediction method based on the integration of the stochastic hybrid automata(SHA) model and the frame of the dynamic fault tree(DFT) is proposed. The SHA model can incorporate the orbit environment, work modes, system configuration, dynamic probabilities and degeneration of components,as well as spacecraft dynamics and kinematics. By introducing the frame of DFT, the system is classified into several layers, and the problem of state combination explosion is artfully *** improved dynamic reliability.model(DRM) based on the Nelson hypothesis is investigated to improve the defect of cumulative failure probability(CFP), which is used to address the failure probability of components in the SHA model. The simulation using the Monte-Carlo method is finally conducted on two satellites, which are deployed with the same multi-gyro subsystem but run on different orbits. The results show that the predicted useful life of the attitude control system(ACS) with consideration of abrupt failure,degradation, and running environment is quite different between the two satellites.

关键词： useful life prediction stochastic hybrid automata (SHA) multi-gyro subsystem dynamic fault tree (DFT) dynamic reliability.

ANALYSIS OF BATCH ARRIVAL QUEUE WITH RANDOMIZED VACATION POLICY AND AN UN-RELIABLE SERVER

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Journal of Systems Science & Complexity 2012年第4期25卷 759-777页

作者： Jau Chuan KE Kai Bin HUANG Department of Applied Statistics National Taichung University of Science and Technology Department of Engineering Information System Development Ardebtec Corporation Ltd.

This paper examines an M[x]/G/1 queueing system with an unreliable server and a delayed repair, in which the server operates a randomized vacation policy with multiple vacations. Whenever the system is empty, the server immediately takes a,vacation. If there is at least one customer found waiting in the queue upon returning from a vacation, the server will be immediately activated for service. Otherwise, if no customers are waiting for service at the end of a vacation, the server either remains idle with probability p or leaves for another vacation with probability 1 -p. Whenever one or more customers arrive when the server is idle, the server immediately starts providing service for the arrivals. The server may also meet an unpredictable breakdown and the repair may be delayed. For such a system the authors derive the distributions of some important system characteristics, such as the system size distribution at a random epoch and at a departure epoch, the system size distribution at the busy period initiation epoch, and the distribution of the idle period and the busy period. The authors perform a numerical analysis for changes in the system characteristics, along with changes in specific values of the system parameters. A cost effectiveness maximization model is constructed to explain the benefits of such a queueing system.

关键词： Cost effectiveness delayed repair randomized vacation queue reliability.

Operational reliability.in Transmission Power Grid

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Journal of Energy and Power Engineering 2012年第1期6卷 150-154页

作者： Daniel Morar Basarab Guzun Ioan Rodean Department of M ＆O ofT. PG. NPGC Transelectrica-SA Bucharest 030786 Romania Department of Power Engineering University Politehnica of Buchares-PUB Bucharest 060042 Romania

The paper presents the methods proposed by the authors to be applied in operation of substations. The substations taken in consideration were rehabilitated by replacing the existing equipments by new equipments, the last generation. The methods consist in study of equipment＇s failures, study of equipment＇s behaviour, study of substation architecture and study of systems operation. Paper presents new equipments on their architecture and performances. The parts of method exposed in this paper are based on the operational reliability. The mathematical methods and new analyses methods are given for resolving the issues on operation of substations. The results of this study will be used to obtain the best solution for operation of the substations. The results of the analysis were applied to some substation from the Transmission Power Grid.

关键词： Power grid rehabilitate reliability.

A Dynamic Model of Sensibility Analysis in Project Evaluation

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Systems Science and Systems Engineering 1994年第2期4卷 125-133页

作者： YE Minqiang(Dept. of I.B.M., Huaqiao University, Quanzhou, Fujian 362011, China)

The study on multi-faCtor Sensibility analysis problem in project evaluation, [1]-I4] gave the static models respectively. In order to raise the practicality and reliability.of sensibility analysis,we propoes a dynamic model in this paper. Comparing with the above, our model has four special features. First, it is suitable for us to optimize and control the Proceeding Project and evaluate the completed Project as well. Second, it offers quantitative measures of sensitivity formulas. Third,it can evaluate project dynamically so that it can obtain much higher precision and reliability.. Fourth,it can deal with Problem which involved in cost of capital fluctuation.

关键词： multi-factor sensibility analysis NPV IRR PI sensitiveness orderinng critical point dynamic fluctuation precision reliability.

A New Method for Grey Forecasting Model Group

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Journal of Systems Engineering and Electronics 2002年第3期13卷 1-7页

作者：李峰王仲东宋中民 Department of Automation Huazhong University of Science and Technology Wuhan 430074 P.R. China

In order to describe the characteristics of some systems, such as the process of economic and product forecasting, a lot of discrete data may be used. Although they are discrete, the inside law can be founded by some methods. For a series that the discrete degree is large and the integrated tendency is ascending, a new method for grey forecasting model group is given by the grey system theory. The method is that it firstly transforms original data, chooses some clique values and divides original data into groups by different clique values; then, it establishes non-equigap GM(1,1) model for different groups and searches forecasting area of original data by the solution of model. At the end of the paper, the result of reliability.of forecasting value is obtained. It is shown that the method is feasible.

关键词： Forecasting Non-equigap GM(1,1) model reliability.

reliability.of a Tissue Microarray in Detecting Thyroid Transcription Factor-1 Protein in Lung Carcinomas

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Chinese Journal of Clinical Oncology 2007年第1期4卷 9-15页

作者： Xiaoyan Bai Hong Shen Department of Pathology Southern Medical University GuangZhou 510515 China

OBJECTIVE To compare the expression of the thyroid transcription factor-1 （TTF-1） in human normal adult type Ⅱ alveolar epithelial cells, embryonic pneumocytes and cancer cells of lung carcinoma and metastatic lymph nodes using a tissue microarray （TMA） along with paired conventional full sections, and to investigate the reliability.of tissue microarrays in detecting protein expression in lung carcinoma. METHODS A lung carcinoma TMA including 765 cores was constructed. TTF-1 protein expression in both TMA and paired conventional full sections were detected by the immunohistochemical SP method using a monoclonal antibody to TTF-1. A PU （Positive Unit） of TTF-1 protein was assessed quantitatively by the Leica Q500MC image analysis system with results from the paired conventional full sections as controls. RESULTS There was no significance between TMA and paired conventional full sections in TTF-1 expression in different nuclei of the lung tissue. CONCLUSION TTF-1 protein expression in lung carcinoma detected by TMA was highly concordant with that of paired full sections. TMA is a reliable method in detecting protein expression.

关键词： lung carcinoma transcription factor-1(TTF-1) liability. tissue microarray thyroid immunohistochemistry reliability.

The reliability.Analysis of the Multi-dimensional Feature Parameters of Radar Signals

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The Reliability Analysis of the Multi-dimensional Feature Pa...

Determining of the Real Condition of High-Voltage Overhead Power Lines

2012 International Conference on Artificial Intelligence and Soft Computing(ICAISC 2012)

作者： Zhibin Yu Yongkui Sun and Weidong Jin School of Electrical Engineering Southwest Jiaotong University Chengdu Sichuan 610031 China

It is a very difficult and pressing issue to how to analyze the reliability.of feature-parameters of complex radar emitter signals. In this paper, the ultimate state model of the signal feature-parameters is proposed based on the structure ultimate state of structure reliability.theory, and the reliability.models of signal feature-parameters are presented by point-estimate theory based on the structure reliability.model. The reliability.of the common feature-parameter PW and TOA are analyzed. The theoretical analysis and experimental results show that the reliability.of feature parameters can be obtained by using the proposed approach when the variable distributions of the feature ultimate state function and bounds of features are known. Moreover, with the SNR and the bound of features increasing, the reliability.of features are rising.

关键词： Radar signal Feature parameters reliability.

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Journal of Energy and Power Engineering 2018年第2期12卷 93-104页

作者： Aleksandar Simovic Faculty of Electrical Engineering University of East SarajevoVuka Karadzica30East Sarajevo71123Bosnia and Herzegovina

Significant investments have been made regarding the construction of a great number of high-voltage overhead power lines of all voltage levels, and now the questions arise on where and how to direct the investments necessary for the maintenance of overhead power lines. To organise the process of maintenance of overhead power lines correctly, it is necessary to have the current information on the condition of particular components of a line. In this paper, special attention has been paid to the real condition of overhead power lines, with the aim of making the decision whether some of the following measures are necessary, and to what extent： the revitalisation for a certain number of years is perceived, the revitalisation up to five years and reconstruction of the overhead power line is performed, its restoration is performed or nothing is done. The approach to the perceiving of real condition of high-voltage overhead power lines is presented on a global block diagram. With the aim of setting out the list of priorities for revitalisation, the criteria have been defined with regards to the real condition of particular components of an overhead power line, as well as pursuant to the role and importance in an electric power system. The correctly defined criteria contribute to the solving of the problem of making a single list of priorities for the revitalisation of high-voltage overhead power lines. In that way, the recommendations are being given to the transmission companies, to achieve a higher reliability.of an electric power system, with a minimum number of cancellations and a maximum extension of working life of all the components of overhead power lines. A correct maintenance of overhead power lines brings large financial savings to the owners of transmission companies, and that is the primary goal in a deregulated environment.

关键词： High-voltage overhead power line real condition reliability.

A Mobile App to Replace the Goniometer? A Pilot Study Focusing on the Measurement of Knee Range of Movement

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Journal of Sports Science 2019年第3期7卷 71-80页

作者： Sara Aspinall Tim Sparks Andrew King Mike Price Steven Godsiff School of Sport Exercise and Health Sciences Loughborough University Loughborough LE11 3TU- UK University Hospitals of Leicester NHS Trust Leicester LE1 5WW -England UK Faculty of Engineering and Computing Coventry University Coventry CV1 5RW England UK Faculty of Health and Life Sciences Coventry University Coventry CV1 5RW England UK

Background: The universal goniometer is commonly used to measure knee range of movement in clinical practice. However, research has demonstrated that the universal goniometer lacks reliability.failing to meet the standard of clinically acceptable error (5°). Objective: This study tested the concurrent validity and intra-rater reliability.of a photographic based “app” developed for feedback in sport, the Hudl Ubersense App, as an alternative instrument for measuring knee range of movement. Methods: Measurements of knee range of movement were made concurrently with the electrogoniometer (the gold standard) and the Hudl Ubersense App across a pre-determined randomised set of 20 functional knee angles between 35° and 130°. This was then repeated. The pre-agreed standard of concurrent validity was that 95% of Hudl Ubersense App measurements would be within 5° of the electrogoniometer and differences were displayed in Bland-Altman plots. Results: Thirty nine (97%) of the forty app readings differed from the corresponding electrogoniometer readings by less than 5°. The mean differences between the electrogoniometer and Hudl Ubersense App measurements over each trial were 1.75° and 0.80° respectively, indicating a high level of concurrent validity. There was less than 1.0° mean difference between the first and second set of results indicating a high level of intra-rater reliability. Conclusions: The results suggest that the Hudl Ubersense App has high levels of concurrent validity (using the electrogoniometer as the gold standard) and intra-rater reliability. scoring better than previous research on the current clinical measuring device, the universal goniometer. The Hudl Ubersense App has clinical advantages over the electrogoniometer, so further research is recommended to determine its inter-rater reliability. acceptability, and appropriate clinical practice procedures.

关键词： Mobile application range of movement knee concurrent validity intra-rater reliability.