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Article
Publication date: 18 April 2017

Qi Zhou, Ping Jiang, Xinyu Shao, Hui Zhou and Jiexiang Hu

Uncertainty is inevitable in real-world engineering optimization. With an outer-inner optimization structure, most previous robust optimization (RO) approaches under…

Abstract

Purpose

Uncertainty is inevitable in real-world engineering optimization. With an outer-inner optimization structure, most previous robust optimization (RO) approaches under interval uncertainty can become computationally intractable because the inner level must perform robust evaluation for each design alternative delivered from the outer level. This paper aims to propose an on-line Kriging metamodel-assisted variable adjustment robust optimization (OLK-VARO) to ease the computational burden of previous VARO approach.

Design/methodology/approach

In OLK-VARO, Kriging metamodels are constructed for replacing robust evaluations of the design alternative delivered from the outer level, reducing the nested optimization structure of previous VARO approach into a single loop optimization structure. An on-line updating mechanism is introduced in OLK-VARO to exploit the obtained data from previous iterations.

Findings

One nonlinear numerical example and two engineering cases have been used to demonstrate the applicability and efficiency of the proposed OLK-VARO approach. Results illustrate that OLK-VARO is able to obtain comparable robust optimums as to that obtained by previous VARO, while at the same time significantly reducing computational cost.

Practical implications

The proposed approach exhibits great capability for practical engineering design optimization problems under interval uncertainty.

Originality/value

The main contribution of this paper lies in the following: an OLK-VARO approach under interval uncertainty is proposed, which can significantly ease the computational burden of previous VARO approach.

Details

Engineering Computations, vol. 34 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 16 April 2018

Qi Zhou, Xinyu Shao, Ping Jiang, Tingli Xie, Jiexiang Hu, Leshi Shu, Longchao Cao and Zhongmei Gao

Engineering system design and optimization problems are usually multi-objective and constrained and have uncertainties in the inputs. These uncertainties might…

Abstract

Purpose

Engineering system design and optimization problems are usually multi-objective and constrained and have uncertainties in the inputs. These uncertainties might significantly degrade the overall performance of engineering systems and change the feasibility of the obtained solutions. This paper aims to propose a multi-objective robust optimization approach based on Kriging metamodel (K-MORO) to obtain the robust Pareto set under the interval uncertainty.

Design/methodology/approach

In K-MORO, the nested optimization structure is reduced into a single loop optimization structure to ease the computational burden. Considering the interpolation uncertainty from the Kriging metamodel may affect the robustness of the Pareto optima, an objective switching and sequential updating strategy is introduced in K-MORO to determine (1) whether the robust analysis or the Kriging metamodel should be used to evaluate the robustness of design alternatives, and (2) which design alternatives are selected to improve the prediction accuracy of the Kriging metamodel during the robust optimization process.

Findings

Five numerical and engineering cases are used to demonstrate the applicability of the proposed approach. The results illustrate that K-MORO is able to obtain robust Pareto frontier, while significantly reducing computational cost.

Practical implications

The proposed approach exhibits great capability for practical engineering design optimization problems that are multi-objective and constrained and have uncertainties.

Originality/value

A K-MORO approach is proposed, which can obtain the robust Pareto set under the interval uncertainty and ease the computational burden of the robust optimization process.

Details

Engineering Computations, vol. 35 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 2 August 2011

Ming‐Yi You and Guang Meng

Most current condition‐based maintenance (CBM) systems using proportional hazards model (PHM) assume that enough historical data are available. However, in many practical…

Abstract

Purpose

Most current condition‐based maintenance (CBM) systems using proportional hazards model (PHM) assume that enough historical data are available. However, in many practical cases, it is usually costly to collect much historical data prior to real practice (model implementation). This paper aims to focus on the necessity and benefits of updating a PHM with new samples generated in the process of model implementation.

Design/methodology/approach

First, an updating scheme is presented and embedded into the entire cycle of PHM establishment, its application/implementation, and its updating. Next, a simulation evaluation is conducted based on a typical degradation model.

Findings

By updating a PHM using newly generated samples, the precision and reliability of residual life (RL) prediction can be improved, especially close to system failure.

Research limitations/implications

The current version of PHM is typically for non‐repairable systems or those systems only receiving renewal maintenance. Further research should focus on the inclusion of the effect of imperfect maintenance.

Practical implications

The updating scheme enables maintenance practitioners to more precisely and reliably predict the RL of an in‐operation system, and enhances further CBM decision making.

Originality/value

This paper highlights the necessity and benefits of updating a PHM using emerging new training resources, which has not received enough attention in existing research/practice of a PHM.

Details

International Journal of Quality & Reliability Management, vol. 28 no. 7
Type: Research Article
ISSN: 0265-671X

Keywords

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Article
Publication date: 1 March 1977

Ron Kaminecki

Currently available on‐line systems historically have been used as retrospective search methodologies. With interest in on‐line retrieval increasing by leaps and bounds…

Abstract

Currently available on‐line systems historically have been used as retrospective search methodologies. With interest in on‐line retrieval increasing by leaps and bounds, the application of these inverted‐file oriented systems to selective dissemination of information (SDI) services bears investigation. Within given user‐specified demands and system constraints, what is the best method of providing an SDI service? A typical batch system is compared with four types of commonly available on‐line SDI systems. The operating parameters of each are outlined, and estimates of bottom‐line costs are given.

Details

Online Review, vol. 1 no. 3
Type: Research Article
ISSN: 0309-314X

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Article
Publication date: 1 April 2003

Georgios I. Zekos

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination…

Abstract

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some legal aspects concerning MNEs, cyberspace and e‐commerce as the means of expression of the digital economy. The whole effort of the author is focused on the examination of various aspects of MNEs and their impact upon globalisation and vice versa and how and if we are moving towards a global digital economy.

Details

Managerial Law, vol. 45 no. 1/2
Type: Research Article
ISSN: 0309-0558

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Article
Publication date: 1 January 1992

Peter Deutsch

New resources and services are being added to the network daily. The number of prospective users of these resources is expanding rapidly, but problems arise when…

Abstract

New resources and services are being added to the network daily. The number of prospective users of these resources is expanding rapidly, but problems arise when individuals attempt to identify, locate, and access networked information in today's dynamic environment. This paper describes Archie, an electronic indexing service for locating information that exists on the Internet. The author describes the Archie service in the context of the Resource Discovery Problem and discusses enhancements that are planned for Archie.

Details

Internet Research, vol. 2 no. 1
Type: Research Article
ISSN: 1066-2243

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Article
Publication date: 1 January 1977

Robert J. D. Saunders

The development and application of a minicomputer based information retrieval system (CAIRS) is described. Capable of performing several different tasks this relatively…

Abstract

The development and application of a minicomputer based information retrieval system (CAIRS) is described. Capable of performing several different tasks this relatively low cost computer system is dedicated to this application and is operated entirely by the information and library staff. Specifically designed for information retrieval the system can perform fast interactive on‐line searches using a visual display. The general operation of the system, factors affecting its selection, and its effect on providing an efficient information service are considered

Details

Program, vol. 11 no. 1
Type: Research Article
ISSN: 0033-0337

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Article
Publication date: 1 September 2003

A. Abdou, J. Lewis and M. Radaideh

This paper presents an internet‐based decision support system (DSS) conceptual proposal for the appraisal stage of healthcare construction projects. The underlying…

Abstract

This paper presents an internet‐based decision support system (DSS) conceptual proposal for the appraisal stage of healthcare construction projects. The underlying philosophy of the approach is to integrate architectural space programming and costestimating processes with a risk assessment approach in order to obtain a more accurate inception cost estimate of the healthcare project along with its preliminary space program outline. The system’s main objectives focus on assisting decision makers in the United Arab Emirates in examining different space program alternatives with their associated capital budgets. In addition, the system will assist in reflecting associated risk factors and affecting budget approval decisions in their inception stage. The Internet is utilized as a mechanism for communicating and updating project data and cost information. This paper describes a conceptual design proposal for the system and the proposed strategy for its design and construction.

Details

Construction Innovation, vol. 3 no. 3
Type: Research Article
ISSN: 1471-4175

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Article
Publication date: 1 January 1988

Marcus Woolley

Developing a library while developing oneself is both an enviable and an alarming experience. This case study is valuable for two reasons: first because it is a uniquely…

Abstract

Developing a library while developing oneself is both an enviable and an alarming experience. This case study is valuable for two reasons: first because it is a uniquely realistic blow‐by‐blow description of the upgrading of a poorly organised, under‐resourced, industrial library. As such, it contains useful practical guidance for the many librarians who have similar problems to contend with. Second, and perhaps even more important, because so rare, is the critical and evaluative attitude taken throughout the report. The author identifies his own mistakes, as well as his successes. The report covers the adoption of new information retrieval systems; the devising of a new issue system for a split‐site library; developing periodicals circulation; evaluation of collection use and relevance; proposing the introduction of on‐line services — against a background of financial stringency and entrenched bureaucracy. The author also evaluates his own performance and the training he received, in his first year of running a one‐person library.

Details

Library Management, vol. 9 no. 1
Type: Research Article
ISSN: 0143-5124

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Article
Publication date: 1 March 1987

Virginia Boucher

The OCLC Interlibrary Loan Subsystem became available for use 1 April 1979. The advantages and disadvantages of the ILL Subsystem are examined, as well as the composition…

Abstract

The OCLC Interlibrary Loan Subsystem became available for use 1 April 1979. The advantages and disadvantages of the ILL Subsystem are examined, as well as the composition and use of the OCLC on‐line union catalogue. Library staffing has had to change because of the way some tasks are now accomplished. Library patrons expect and receive better service. OCLC is conspicuously successful in helping libraries to cope with ever‐increasing numbers of interlibrary loan requests.

Details

Interlending & Document Supply, vol. 15 no. 3
Type: Research Article
ISSN: 0264-1615

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