List of Titles

A bi-objective dynamic model for multi-state weighted k-out-of-n system reliability

- Khorshidi, Hadi, Gunawan, Indra, Ibrahim, Yousef

Authors: Khorshidi, Hadi , Gunawan, Indra , Ibrahim, Yousef
Date: 2015
Type: Text , Conference paper
Relation: 25th European Safety and Reliability Conference, ESREL 2015; Zurich, Switzerland; 7th-10th September 2015 p. 2229-2234
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Description: Nowadays, improving system reliability is becoming an important criterion for engineering industries. Many studies have been developed to evaluate the reliability of the systems which is the first step in system improvement. Most of these studies have been done in non-dynamic conditions in which the components have the constant reliability values during functioning periods. However, the components' reliability level varies over time due to both failures and maintenance actions. Therefore, time dimension should be added into system reliability evaluation. In this paper, a dynamic assessment is presented for multi-state weighted k-out-of-n systems. The k-out-of-n system is a popular structure in fault-tolerant systems in which n components work in parallel form with a pre-defined k as a condition. This dynamic assessment considers the reliability variation of the components over finite and discrete time periods. It provides an opportunity to assign decision variables for each functioning period, and analyze the impact of each decision on the whole system reliability. In addition, the income generated during each period is defined as an importance weight of the components. Therefore, the present value of the system is obtained by Universal Generating Function (UGF) and engineering economics' tools. Furthermore, an optimization model is developed to find optimal decisions based on system reliability and cost. Since the system reliability is estimated by money, the expected profit of the system can be as the objective function. As a result, the objective function can maximize system reliability and minimize system cost simultaneously. A Matlab programming is created for a numerical example to illustrate the proposed model. © 2015 Taylor & Francis Group, London.

A new modified FMEA model for ranking the risk of maintenance waste considering hierarchy of root causes and effects

- Sutrisno, Agung, Gunawan, Indra, Khorshidi, Hadi, Tangkuman, Stenly

Authors: Sutrisno, Agung , Gunawan, Indra , Khorshidi, Hadi , Tangkuman, Stenly
Date: 2015
Type: Text , Journal article
Relation: International Journal of Quality Engineering and Technology Vol. 5, no. 3-4 (2015), p. 217-237
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Description: Implementing sustainable manufacturing practice requires efficiency of the resource utilisation and activities which add value to the operations. From this point of view, development of an improved methodology to access the criticality of non- Added value (waste) is important and believed to support the realisation of sustainable manufacturing operation. While previous studies on improving methodology to support sustainable operation from product and process design are abundantly available in the references, the contribution from maintenance field is in contrary. The goal of this study is to modify the quality improvement tool, failure mode and effect analysis (FMEA) to access the criticality of waste in maintenance operation. In an attempt to realise the above goal, an empirical study to propose the theoretical and actual maintenance waste from industrial practice is undertaken. In order to assist maintenance 218 A. Sutrisno et al. decision maker to quantify criticality of maintenance waste occurrence, a new model to rank waste maintenance mode, called the waste priority number (WPN) is given. Illustrative on using model for practical purpose is given.. © 2015 Inderscience Enterprises Ltd.

A value-driven approach for optimizing reliability-redundancy allocation problem in multi-state weighted k-out-of-n system

- Khorshidi, Hadi, Gunawan, Indra, Ibrahim, Yousef

Authors: Khorshidi, Hadi , Gunawan, Indra , Ibrahim, Yousef
Date: 2016
Type: Text , Journal article
Relation: Journal of Manufacturing Systems Vol. 40, no. (2016), p. 54-62
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Description: This study concentrates on optimizing a multi-state weighted k-out-of-n system consisting of different types of reparable components. An optimization model is developed to decide upon both optimal redundancy allocation and best maintenance activities for reliability allocation. The optimization model is to maximize system reliability and minimize system cost simultaneously. To reach this goal, a financial view has been employed to estimate the system reliability, and combine it with system cost. The proposed model determines the number of each component type in the system, and the maintenance actions and the time at which they should be applied. Also, the model is programmed by MATLAB, and Genetic Algorithm is used to solve a practical case. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

An investigation on imperialist competitive algorithm for solving reliability-redundancy allocation problems

- Khorshidi, Hadi, Gunawan, Indra, Sutrisno, Agung, Nikfalazar, Sanaz

Authors: Khorshidi, Hadi , Gunawan, Indra , Sutrisno, Agung , Nikfalazar, Sanaz
Date: 2015
Type: Text , Conference paper
Relation: 2015 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM); Singapore, Singapore; 6th-9th December 2015 p. 1041-1045
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Description: Reliability-redundancy allocation problems (RRAPs) are optimization models that try to find the optimal number of redundant components and their reliability levels simultaneously. Many studies have been developed to solve RRAPs in recent years. There are some specific RRAP models for various system structures to maximize system reliability subject to cost, volume and weight constraints. Different meta-heuristic algorithms have been used in order to reach the best objective function value. In this study, an investigation is done on imperialist competitive algorithm (ICA) to maximize models for series and bridge systems. ICA is used by adjusting different values to algorithm's parameters. This investigation recognizes which combination is the most suitable for solving the RRAPs by ICA. Each combination has been run for 35 times. Therefore, the combinations are compared by descriptive statistics' measures and analysis of variance (ANOVA). Furthermore, the best obtained solution is compared with the previous studies.

An optimization model for multi-state weighted kout-of-n system reliability value

- Korshidi, Hadi, Gunawan, Indra, Ibrahim, Yousef

Authors: Korshidi, Hadi , Gunawan, Indra , Ibrahim, Yousef
Date: 2013
Type: Text , Conference proceedings
Relation: IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, Vienna, Austria Nov. 2013, p.4357-4361
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Description: A reliability optimization model is proposed in this paper for multi-state weighted k-out-of-n systems. In this model, income generated by components through each functioning period is used as a reliability index. Therefore, time value of money is used in the presented optimization model to estimate both system's reliability and cost. The system reliability is evaluated by Universal Generating Function (UGF). The model's objective function is to maximize the net present value (NPV) of the system. Therefore, it would maximize the system reliability and minimize the system cost simultaneously. A numerical example is presented in this paper to illustrate the model by finding the optimal design of the system, and the best time for maintenance plan. Also, a discussion is provided based on the result.

Analysis of cost and schedule performance of international development projects

- Ahsan, Kamrul, Gunawan, Indra

Authors: Ahsan, Kamrul , Gunawan, Indra
Date: 2010
Type: Text , Journal article
Relation: International Journal of Project Management Vol. 28, no. 1 (2010), p. 68-78
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Description: This study focuses on cost and schedule issues of international development (ID) projects. Through empirical analysis we examine ID project cost and schedule performance and the main reasons for poor project outcome. We look at 100 projects that are sponsored by the Asian Development Bank and hosted by several Asian countries. The study identifies that most late projects experience cost underrun – an unusual cost and schedule variation relation in projects. Further we identify the root causes of project delay and cost underrun. Research findings will benefit ID project professionals, organizations and the ID project body of knowledge. The study can be extended to analyse other developing country projects sponsored by different donors.

Analysis of design structure matrix methods in design process improvement

- Gunawan, Indra

Authors: Gunawan, Indra
Date: 2012
Type: Text , Journal article
Relation: International Journal of Modelling and Simulation Vol. 32, no. 2 (2012), p. 95-103
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Description: In this paper, design structure matrix (DSM) methods are presented to manage design iteration or rework which is inherent in the design process. Three DSM methods: path searching, powers of the adjacency matrix, and reachability matrix methods are discussed. Their advantages and disadvantages with respect to the project scope are summarized. As a case study, DSM methods are implemented to reduce the design iteration or rework in a complex engineering project. The main advantage of the DSM methods over traditional project management tools such as CPM or Gantt chart is in compactness and ability to present an organized and eﬃcient mapping among tasks that is clear and easy to read regardless of size.

Analysis of education and practical relevance of project management topics in New Zealand

- Gunawan, Indra

Authors: Gunawan, Indra
Date: 2015
Type: Text , Journal article
Relation: International Journal of Project Organisation and Management Vol. 7, no. 2 (2015), p. 174-183
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Description: The objective of this paper is to analyse the education of project management (PM) and its practical relevance in New Zealand. The research has been done through a survey analysis of PM practitioners and academics. The PM practitioners were asked which PM topics are widely used in the industry. The academics were also asked through a parallel survey which PM topics are considered important at a tertiary level and taught to students. It can be seen from the results that contemporary education of PM has improved vastly and is relevant with its practice. The findings are important for both practitioners and academics to identify the gap between project management education and industry needs. Copyright © 2015 Inderscience Enterprises Ltd.

Application of fuzzy risk analysis for selecting critical processes in implementation of SPC with a case study

- Khorshidi, Hadi, Gunawan, Indra, Nikfalazar, Sanaz

Authors: Khorshidi, Hadi , Gunawan, Indra , Nikfalazar, Sanaz
Date: 2016
Type: Text , Journal article
Relation: Group Decision and Negotiation Vol. 25, no. 1 (2016), p. 203-220
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Description: Fuzzy risk analysis is widely used in risk assessment of components by linguistic terms. Fuzzy numbers are used to quantify the associated uncertainty. This study employs fuzzy risk analysis to evaluate processes for implementing statistical process control (SPC) in a specified manufacturing system. To reach this goal, fuzzy risk analysis has been applied based on both ranking and similarity of generalized trapezoidal fuzzy numbers in a stepwise procedure. Therefore, a new approach has been introduced for fuzzy risk analysis of processes to overcome the shortcomings of previous fuzzy risk analysis approaches. As a result, fuzzy risk analysis is used as a decision making technique to select critical processes under uncertainty. Also, the application of the proposed SPC implementation algorithm is illustrated in the manufacturing line of a car battery factory. © 2015, Springer Science+Business Media Dordrecht.

Application of Markov Process technique for optimal maintenance in a power station

- Gunawan, Indra, Patel, Deepak

Authors: Gunawan, Indra , Patel, Deepak
Date: 2012
Type: Text , Journal article
Relation: GSTF Journal of Mathematics, Statistics and Operations Research Vol. 1, no. 1 (2012), p. 99-104
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Description: Maintenance, reliability and availability of Pulverised Fuel Mills are of vital importance for the effective and efficient running of boiler at any brown coal power station. Achieving these targets become more critical when the unit boiler and turbine have been upgraded with no major upgrade on mills. Mill redundancy play major role in overall boiler operation and performance. In this paper, present mill operating strategy at Loy Yang Power station is challenged and revised strategy is proposed with strong evidences proved with the application of Markov Processes. Markov analysis is done at mill system level to establish the facts about the effects of mill operation on system availability. Short term and long term benefits of revised strategy are also discussed. Management is now convinced and actual trials have started. Mill maintenance strategies shall be reviewed and revised based on this work. It is also expected to gain considerable savings on mill maintenance costs in coming years if proposed operating strategy is adopted.

Application of Markov process technique for optimal maintenance in a power station

- Patel, Deepak, Gunawan, Indra

Authors: Patel, Deepak , Gunawan, Indra
Date: 2012
Type: Text , Conference paper
Relation: Asset Management Conference Vol. 1, p. 99-104
Full Text: false
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Description: Maintenance, reliability and availability of Pulverised Fuel Mills are of vital importance for the effective and efficient running of boiler at any brown coal power station. Achieving these targets become more critical when the unit boiler and turbine have been upgraded with no major upgrade on mills. Mill redundancy play major role in overall boiler operation and performance. In this paper, present mill operating strategy at Loy Yang Power station is challenged and revised strategy is proposed with strong evidences proved with the application of Markov Processes. Markov analysis is done at mill system level to establish the facts about the effects of mill operation on system availability. Short term and long term benefits of revised strategy are also discussed. Management is now convinced and actual trials have started. Mill maintenance strategies shall be reviewed and revised based on this work. It is also expected to gain considerable savings on mill maintenance costs in coming years if proposed operating strategy is adopted.

Application of numerical design structure matrix method in engineering projects management

- Gunawan, Indra

Authors: Gunawan, Indra
Date: 2009
Type: Text , Journal article
Relation: Operations and Supply chain Management: An International Journal Vol. 2, no. 1 (2009 2009), p. 1-10
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Description: In this paper, ways of improving planning, execution and management of projects using Numerical Design Structure Matrix (NDSM) method are presented to address interdependency of feedback and iteration, which is common in engineering projects management. The NDSM is an alternative approach to traditional project management tools such as Program Evaluation and Review Technique (PERT), Critical Path Method (CPM), and Gantt chart that can only allow the modelling of sequential and parallel processes in projects. As a case study, the model is tested on a set of tasks in a complex petroleum oil field development project, where task sensitivity and information variability attributes are derived. By applying the NDSM method, project duration is optimized and hence total cost of the project is reduced significantly.

Applying UGF Concept to Enhance the Assessment Capability of FMEA

- Khorshidi, Hadi, Gunawan, Indra, Ibrahim, Yousef

Authors: Khorshidi, Hadi , Gunawan, Indra , Ibrahim, Yousef
Date: 2016
Type: Text , Journal article
Relation: Quality and Reliability Engineering International Vol. 32, no. 3 (Apr 2016), p. 1085-1093
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Description: The purpose of this paper is to propose a modified version of Failure Mode and Effects Analysis (FMEA) to alleviate its drawbacks. FMEA is an important tool in risk evaluation and finding the priority of potential failure modes for corrective actions. In the proposed method, the Universal Generating Function (UGF) approach has been used to improve the assessment capability of the conventional Risk Priority Number (RPN) in ranking. The new method is named as URPN. It generates the most number of unique values in comparison with the previous methods and considers relative importance for the parameters while it is easy to compute. More unique numbers help to avoid from having the same priority level for different failure modes which represent various risk levels. A case study has been employed to demonstrate that the URPN not only can improve the shortcomings but also is able to provide accurate values for risk assessment. Copyright (c) 2015 John Wiley & Sons, Ltd.

Challenges of recovering by-passed condensate in Al-Raja field utilizing MBO method

- Gunawan, Indra, Al-Abbasi, Omar

Authors: Gunawan, Indra , Al-Abbasi, Omar
Date: 2011
Type: Text , Conference paper
Relation: SPE Asia Pacific Oil and Gas Conference and Exhibition 2011 p. 998-1017
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Description: This paper presents a case study on a reservoir simulation modeling of recycling gas condensate using Modified Black Oil formulation (MBO) to identify and recover the by-passed condensate in Al-Raja Field. Al-Raja field is a good candidate to utilize MBO formulation instead of fully compositional due to following reasons (1) Gas injection/recycling is able to maintain the reservoir pressure above or at the dew point pressure in Al-Raja Field. (2) by keeping reservoir pressure above dew point pressure, gas injection will prevent any Retrograde Liquid Deposit (RLD) occured in the reservoir. It was well accepted methodology that MBO can be used in lean to medium rich gas condensate reservoir under gas cycling above dew point. Al-Raja field is located in the Eastern part of the Marib-AlJawf Basin Republic of Yemen. The field has a moderate-size medium rich gas condensate reservoir with an average gas production rate of 750 MMscf/D from 18 wells. The lean gas is being re-injected back into the reservoir using line-drive pattern wells. Some make up gas from nearby fields was provided to replace fuel and shrinkage volumes. The high vertical relief of the field structure leads to significant temperature gradient that resulted in challenges to model the oil-gas ratio (Rv). The primary objective of the study is (1) to evaluate the current gas recycling performance at well and field level, (2) identify the location of current by-passed condensate (3) utilize the model to improve and optimize the liquid recovery through several options of optimum field developments (infill wells). To achieve the objectives, 3-D Static and Dynamic models with 4 components MBO definition were constructed. In this study, we will show how to generate PVT Modified Black Oil (MBO) properties such as solution gas-oil ratio (Rs), oil-gas ratio (Rv), oil formation volume factor (Bo), and gas formation factor (Bg), from PVT-EOS. Whitson and Torp procedures were selected to calculate MBO properties from PVT experimental data of gas condensate. The use of the MBO approach enabled us to perform faster field performance history matching compared with the compositional. This approach preserves less run time to conduct the Al-Raja prediction including infill drilling optimization. The condensate-gas ratio distribution achieved after the history match process guided us to locate the optimum infill well locations in by-passed area for the future development. Moderate condensate areas were located, and several wells have been drilled and proved to be successful. More infill wells were recommended to raise the field production and recover the remaining reserve.

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