The Experts below are selected from a list of 23901 Experts worldwide ranked by ideXlab platform
Shigeru Yamada - One of the best experts on this subject based on the ideXlab platform.
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a flexible stochastic differential equation model in distributed development environment
European Journal of Operational Research, 2006Co-Authors: Yoshinobu Tamura, Shigeru YamadaAbstract:Abstract In recent years, the dependence on a computer system has become large in our social life. Especially, a software development environment has been changing into distributed development environment interconnected with work-stations. Therefore, it becomes more difficult for software developers to produce highly reliable software systems efficiently, because of the more diversified and complicated software Requirements. Also, in the software development process, the software testing-cost occupies more than a half of the total development cost. In this paper, we derive a flexible stochastic differential equation model describing a fault-detection process during the system testing phase of the distributed development environment by applying a mathematical technique of stochastic differential equations of an It o ˆ type. Moreover, we discuss optimal software release problems based on the reusable rate of software components minimizing the expected total software cost, and also minimizing the cost with satisfying a software Reliability Requirement based on the coefficient of variation.
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economic analysis of software release problems with warranty cost and Reliability Requirement
Reliability Engineering & System Safety, 1999Co-Authors: M Kimura, T Toyota, Shigeru YamadaAbstract:Abstract We discuss optimal software release problems which consider both a present value and a warranty period (in the operational phase) during which the developer has to pay the cost for fixing any faults detected. It is very important with respect to software development management that we solve an optimal software testing time by integrating the total expected testing cost and the Reliability Requirement. We apply a nonhomogeneous Poisson process model to the formulation of a software cost model and analyze three typical cases of the cost model. Moreover, we derive several optimal release polices. Finally, numerical examples are shown to illustrate the results of the optimal policies.
Yanzhen Zhang - One of the best experts on this subject based on the ideXlab platform.
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Development of an automatic subsea blowout preventer stack control system using PLC based SCADA.
Isa Transactions, 2011Co-Authors: Fei Wang, Xiaojie Tian, Yanzhen ZhangAbstract:Abstract An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high Reliability Requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human–machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human–machine interface.
Fei Wang - One of the best experts on this subject based on the ideXlab platform.
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Development of an automatic subsea blowout preventer stack control system using PLC based SCADA.
Isa Transactions, 2011Co-Authors: Fei Wang, Xiaojie Tian, Yanzhen ZhangAbstract:Abstract An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high Reliability Requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human–machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human–machine interface.
Xin Wang - One of the best experts on this subject based on the ideXlab platform.
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modeling for point non point source effluent trading perspective of non point sources regulation in china
Science of The Total Environment, 2002Co-Authors: Wei Zhang, Xin WangAbstract:In the past decades, little abatement efforts have been implemented on China's non-point source water pollution, and studies aiming at non-point sources regulation were also rare. Watershed abatement trading between point and non-point sources may serve as a cost-effective way to deal with the problem. The inherent uncertainty of non-point emissions, however, could affect the feasibility and outcome of point-non-point effluent trading. The purpose of this paper is to model the watershed point-non-point abatement trading incorporating the uncertainty of non-point source emissions, and to examine its impacts on trading equilibrium and trading ratio. The uncertainties of non-point emissions were taken into consideration by setting an acceptable probability by which the watershed emission constraints were achieved. Using the watershed optimization model, the optimal abatement allocation and trading ratio were explicitly illustrated. It was found that they were affected significantly by the variances of non-point emissions, the Reliability Requirement assigned to the non-point abatement, and the marginal abatement costs of point and non-point sources. Since the variances of non-point emissions may increase or decrease at the abatement level, the impacts of these factors were discussed in different circumstances. Based on the illumination of the trading model, future directions and implications of point-non-point trading in China were discussed.
Branka Vucetic - One of the best experts on this subject based on the ideXlab platform.
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burstiness aware bandwidth reservation for ultra reliable and low latency communications in tactile internet
IEEE Journal on Selected Areas in Communications, 2018Co-Authors: Zhanwei Hou, Tony Q. S. Quek, Changyang She, Branka VuceticAbstract:The Tactile Internet that will enable humans to remotely control objects in real time by tactile sense has recently drawn significant attention from both academic and industrial communities. Ensuring ultra-reliable and low-latency communications with limited bandwidth is crucial for Tactile Internet. Recent studies found that the packet arrival processes in Tactile Internet are very bursty. This observation enables us to design a spectrally efficient resource management protocol to meet the stringent delay and Reliability Requirements while minimizing the bandwidth usage. In this paper, both model-based and data-driven unsupervised learning methods are applied in classifying the packet arrival process of each user into high or low traffic states, so that we can design efficient bandwidth reservation schemes accordingly. However, when the traffic-state classification is inaccurate, it is very challenging to satisfy the ultra-high Reliability Requirement. To tackle this problem, we formulate an optimization problem to minimize the reserved bandwidth subject to the delay and Reliability Requirements by taking into account the classification errors. Simulation results show that the proposed methods can save 40%-70% bandwidth compared with the conventional method that is not aware of burstiness, while guaranteeing the delay and Reliability Requirements. Our results are further validated by the practical packet arrival processes acquired from experiments using a real tactile hardware device.