The Experts below are selected from a list of 195426 Experts worldwide ranked by ideXlab platform
Won-jong Kim - One of the best experts on this subject based on the ideXlab platform.
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Real-time Operating Environment for networked control systems
Proceedings of the 2005 American Control Conference 2005., 1Co-Authors: A. Ambike, Won-jong KimAbstract:This paper discusses the real-time aspects of networked control systems' (NCSs) Operating Environments. An open-loop unstable magnetic-levitation (Maglev) test bed was constructed and used to develop an NCS with a real-time application interface (RTAI) Operating Environment. A client-server architecture on a local area network (LAN) was developed with the network communication based on the user datagram protocol (UDP). The implementation of an event-driven server and a time-driven client presented in this paper facilitates a simple timing scheme that does not require clock synchronization between the client and the server. A novel prediction scheme involving the multiple-step-ahead generation of control signals is used to maintain system stability in the presence of excessive time delays and packet losses in the communication network. The current system can compensate for up to 20% data-packet losses without losing stability with the Maglev real-time-control test bed in the communication network.
A. Ambike - One of the best experts on this subject based on the ideXlab platform.
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Real-time Operating Environment for networked control systems
Proceedings of the 2005 American Control Conference 2005., 1Co-Authors: A. Ambike, Won-jong KimAbstract:This paper discusses the real-time aspects of networked control systems' (NCSs) Operating Environments. An open-loop unstable magnetic-levitation (Maglev) test bed was constructed and used to develop an NCS with a real-time application interface (RTAI) Operating Environment. A client-server architecture on a local area network (LAN) was developed with the network communication based on the user datagram protocol (UDP). The implementation of an event-driven server and a time-driven client presented in this paper facilitates a simple timing scheme that does not require clock synchronization between the client and the server. A novel prediction scheme involving the multiple-step-ahead generation of control signals is used to maintain system stability in the presence of excessive time delays and packet losses in the communication network. The current system can compensate for up to 20% data-packet losses without losing stability with the Maglev real-time-control test bed in the communication network.
Behzad Ghodrati - One of the best experts on this subject based on the ideXlab platform.
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Operating Environment-Based Availability Importance Measures for Mining Equipment (Case Study: Sungun Copper Mine)
Journal of Failure Analysis and Prevention, 2017Co-Authors: Ali Nouri Qarahasanlou, Mohammad Ataei, Reza Khalokakaie, Behzad GhodratiAbstract:When a system’s performance is inadequate, the concept of availability importance can be used to improve it. The availability of an item depends on the combined aspects of its reliability and maintainability. In a system consisting of many subsystems, the availability of some subsystems is more important to system performance than others. The availability measure determines the priority of availability across subsystems. Most researchers only consider operation time and ignore the influence of the Operating Environment; therefore, their estimations are not accurate enough. In contrast to previous research, we focus on the influence of the Operating Environment on the system/subsystem’s characteristics with a view to prioritizing them based on the importance of availability. The paper considers part of the mining fleet system of Sungun copper mine, including the wagon drill, loader, bulldozer, and dump truck subsystems. We identify an ordered list of possibilities for availability improvement and suggest changes or remedial actions for each item to either reduce its failure rate or reduce the time required to repair it.
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Tire demand planning based on reliability and Operating Environment
International. Journal of Mining & Geo-Engineering, 2016Co-Authors: Ali Nouri Qarahasanlou, Reza Khalokakaie, Behzad Ghodrati, Mohammad Ataei, Rasoul JafareiAbstract:Tires represent a critical spare part in mines. There is a shortage of medium and large tires. In addition, with increased mining activities and the creation of new mines, the demand for tires has increased significantly. Thus, it is particularly important for mining engineers to identify tire characteristics and correctly manage the spare part inventory. Spare parts management is critical from an operational perspective, especially in asset intensive industries, such as mining, as well as in organizations owning and Operating costly assets. A knowledge of the tires’ behavior (historical data) must be considered together with the Operating Environment conditions (covariates). This study uses multiple regression analysis based on Cox’s regression model to incorporate machine Operating Environment information into systems reliability analysis to estimate spare parts. It considers a proportional hazard model and a stratified Cox regression model for time independent and dependent covariates. Based on the results, the study develops a mathematical model for spare parts estimation at the component level for non-repairable parts (tires). It validates the outcomes using a case study of loader tires in Sungun mine in Iran. There is a significant difference in the results of spare parts forecasting and inventory management when considering and not considering covariates.
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SPARE PARTS ESTIMATION FOR MACHINE AVAILABILITY IMPROVEMENT ADDRESSING ITS RELIABILITY AND Operating Environment — CASE STUDY
International Journal of Reliability Quality and Safety Engineering, 2013Co-Authors: Behzad Ghodrati, Alireza Ahmadi, Diego GalarAbstract:Industrial operation cost analysis shows that, in general, maintenance represents a significant proportion of the overall Operating costs. Therefore, the improvement of maintenance follows the final goal of any company, namely, to maximize profit. This paper studies spare parts availability, an issue of the maintenance process, which is an important way to improve production through increased availability of functional machinery and subsequent minimization of the total production cost. Spare parts estimation based on machine reliability characteristics and Operating Environment is performed. The study uses an improved statistical-reliability (S-R) approach which incorporates the system/machine Operating Environment information in systems reliability analysis. For this purpose, two methods of Poisson process and renewal process are introduced and discussed. The renewal process model uses a multiple regression type of analysis based on Cox's proportional hazards modeling (PHM). The parametric approaches with baseline Weibull hazard functions and time-independent covariates are considered, and the influence of Operating Environment factors on this model is analyzed. The outputs represent a significant difference in the required spare parts estimation when considering or ignoring the influence of the relevant system Operating Environment. The difference is significant in the sense of spare parts forecasting and inventory management which can enhance the parts and consequently machine availability, leading to economical operation and savings.
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product support improvement by considering system Operating Environment a case study on spare parts procurement
International Journal of Quality & Reliability Management, 2012Co-Authors: Behzad Ghodrati, Dragan Benjevic, Andrew K S JardineAbstract:Purpose – The ongoing availability of existing industrial systems/machines depends to a great extent on the form and level of product support. Product support, or the after sale service of a product, is important because it assures the expected function of the product in its operational phase. Product support is affected by a number of factors, including system reliability and maintainability characteristics and the Operating Environment. The purpose of this paper is to analyze the influence of time independent external factors of industrial systems on product support requirements and spare parts need.Design/methodology/approach – This paper, after discussing the factors influencing product support, describes a method to estimate spare part requirements based on estimation of the actual reliability of a product under the influence of the product‐Operating Environment using a proportional hazard model. A spare parts estimation software, Spare Management Software (SMS), is used to check the results. Then a ...
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reliability and Operating Environment based spare parts estimation approach
Journal of Quality in Maintenance Engineering, 2005Co-Authors: Behzad Ghodrati, Uday KumarAbstract:Purpose – With continuous technological development in the twenty‐first century, the industry and industrial systems have become complex and making their availability more critical. In this context, the product support and its related issues such as spare parts play an important role. Lack of timely or incomplete support, such as the lack of spare parts when required, is likely to cause unexpected downtimes, which in turn often lead to incompensatable losses. Therefore the importance of predicting the correct support to keep the system functionally available needs to be emphasized. Required number of spare parts could be obtained based on technical and life parameters. This paper seeks to examine the system reliability and Operating Environment, which are the two parameters to be considered in this article.Design/methodology/approach – A model is provided in this paper to determine the number of required spare parts with respect to the effect of the external factors, except time, on the reliability charac...
V.s. Catao - One of the best experts on this subject based on the ideXlab platform.
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On the Design of the Seljuk-Amoeba Operating Environment
Journal of the Brazilian Computer Society, 1997Co-Authors: Francisco Vilar Brasileiro, E. De Lima Gallindo, Sheila Regine Almeida Vasconcelos, V.s. CataoAbstract:Building dependable distributed applications is not an easy task. Designers of such systems have followed two complementary approaches to reduce design complexity, namely: i) the use of appropriate developing tools; and ii) the choice of the most restrictive failure semantics possible for the components that form the systems underlying execution layer. The Seljuk model uses these two approaches to specify a structured way of providing fault tolerance services in the context of distributed Operating Environments, thus facilitating the construction and execution of dependable distributed applications. In this paper we present the design of the Seljuk-Amoeba Operating Environment, which follows the Seljuk model to enhance the Amoeba distributed Operating system with the provision of fault tolerance services
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SCCC - Reliable processing on the Seljuk-Amoeba Operating Environment
Proceedings 17th International Conference of the Chilean Computer Science Society, 1Co-Authors: E. De Lima Gallindo, Francisco Vilar Brasileiro, V.s. CataoAbstract:Processing on the Amoeba distributed Operating system is not fault tolerant. The only concern of its processing service is to perform load balancing on the existing processors, trying to find the processor that best suits a particular process in terms of memory availability and CPU speed. We introduce a fault tolerant processing service for the Amoeba system. This service is used in the implementation of the Seljuk-Amoeba Operating Environment, which offers processing service with different controlled failure semantics on a per process basis.
Adrian Stavert-dobson - One of the best experts on this subject based on the ideXlab platform.
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Safety and the Operating Environment
Health Information Systems, 2015Co-Authors: Adrian Stavert-dobsonAbstract:The causes of clinical hazards in Health IT are complex. Certainly confining the analysis to the availability or otherwise of the electronic service is grossly over-simplistic. Hazards typically arise through the complex interplay of the technology and its human operators. Only when this relationship is understood and the constraints of the Operating Environment appreciated can one foresee potential failure modes and their likely impact on patients. Human error plays a subtle role in the causality chain and an examination of its root causes yields a richer seam of data. With careful thought and attention to detail, systems can be designed and engineered to encourage users to make safe choices. This chapter examines Health IT’s role in the socio-technical Environment, the nature of human failure and how a culture of safety facilitates an organisation’s operation of a clinical risk management system.
