Fuzzy reliability of a turbines structure system using the right triangular fuzzy number

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pooja Dhiman ◽  
Amit Kumar
Keyword(s):  
Fuzzy Number ◽  
Oil And Gas ◽  
Time To Failure ◽  
Content Type ◽  
Reliability Indices ◽  
Fuzzy Environment ◽  
Generalized Fuzzy Number ◽  
The Right ◽  
The Impact ◽  
Mean Time

PurposeThe purpose of this paper is to investigate the performance of a turbine structure of the oil and gas Egyptian company in terms of reliability, mean time to failure (MTTF), mean time to repair (MTTR) and mean time between failures (MTBF) under fuzzy environment and working criteria. This paper examines the impact of the failure of various components on the complete turbine structure of the oil and gas system.Design/methodology/approachTo overcome the problem of uncertain behavior of available data for various components, the right triangular generalized fuzzy number (RTrGFN) is proposed to be taken into the account to express the uncertainty which attains some tolerance in data. Furthermore, reliability indices are calculated with the help of the Lambda Tau method and the arithmetic operations on right generalized triangular fuzzy numbers (RTrGFN).FindingsThis paper explores the reliability of a repairable 3 out of 4 structure of turbines and along with the other parameters namely MTTF, MTTR and MTBF; under a fuzzy environment. Failure rates and repair times are expected to be exponential. The ranking of components of the structure is being found to decide the priority for maintenance.Originality/valueThis paper investigates the performance of the system with different spread/tolerance like 15%, 25% and 50% of crisp data. It helps to predict realistic results in the range value. To enhance the system's performance, the most important item of the system requires greater attention. For this, the authors find the sensitive part by ranking. For ranking, an extended approach has been developed to find the sensitive unit of the system by using the right triangular generalized fuzzy number. This paper explores the most and least sensitive component of the system, which helps the maintenance department to plan the maintenance action.

Signature reliability of binary state node in complex bridge networks using universal generating function

2019 ◽  
Vol 36 (2) ◽  
pp. 186-201 ◽  
Author(s):  
Soni Bisht ◽  
S.B. Singh
Keyword(s):  
Generating Function ◽  
Time To Failure ◽  
Content Type ◽  
Reliability Indices ◽  
The Past ◽  
Reliability Characteristics ◽  
Binary State ◽  
Bridge Networks ◽  
Mean Time ◽  
Universal Generating Function

PurposeThe purpose of this paper is to evaluate various reliability measures like reliability, expected lifetime (mean time to failure), signature reliability and compare networks based on the different flows.Design/methodology/approachThe reliability characteristics of complex bridge networks have been evaluated using different algorithms with the help of universal generating function (UGF). Further, the signature reliability of the considered networks has been determined using Owen’s method.FindingsThe present paper proposes an efficient algorithm to compute the reliability indices of complex bridge networks having i.i.d. lifetime components (nodes, edges) with the help of UGF and Owen’s method. This study reveals that a slight change in the complex bridge network affects the reliability significantly. Finally, by the reliability structure function, proposed algorithms are used to find the signature and MTTF. From signature, we have determined the different failure probabilities corresponding to edges of the network.Originality/valueIn this work, we have evaluated reliability characteristics and signature reliability of the complex bridge networks using UGF method and Owen’s method respectively unlike done in the past.

Buyer-assisted lean intervention in supplier firms: a supplier development approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Imranul Hoque
Keyword(s):  
Financial Incentives ◽  
Large Scale ◽  
Qualitative Data ◽  
Research Approach ◽  
Capability Development ◽  
Content Type ◽  
Production Capability ◽  
Lean Tools ◽  
The Right ◽  
The Impact

PurposeThis study aims to investigate how buyer-assisted lean intervention in garment supplier factories affects garment suppliers' productivity and production capability development.Design/methodology/approachEmploying a qualitative research approach and a lean intervention design, a multiple case study method was adopted for this study. Quantitative data on productivity performance and qualitative data on production capability development were collected from a Danish buyer and their four corresponding garment suppliers. Collected data were analysed using standard lean measurement tools and qualitative data analysis techniques.FindingsThis study demonstrates that buyer-assisted lean intervention is a useful strategy for garment suppliers to enhance their productivity and production capability. However, suppliers need to select the right lean tools, ensure seriousness and commitment to lean initiatives, substantial involvement of top management and workers, arrange formal and informal training, provide performance-based financial/non-financial incentives and nurture a learning culture to facilitate suppliers' production capability development.Research limitations/implicationsThis study implemented few lean tools in a single sewing line in four supplier factories for a short intervention duration. Thus, there is a scope for future studies to investigate the impact of the lean intervention on a large scale.Practical implicationsThe findings of this study might bring new insights to the management of buyer and supplier firms concerning how buyers could involve in suppliers' lean intervention initiatives and what suppliers need to ensure to develop production capability.Originality/valueFor the first time, this study engaged a buyer in suppliers' lean intervention initiatives to improve productivity and production capability in the garment industry of a developing country.

Performance measurement and resource sharing among business sub-units in the presence of non-discretionary factors

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rita Shakouri ◽  
Maziar Salahi
Keyword(s):  
Resource Sharing ◽  
Content Type ◽  
Development Level ◽  
Proposed Model ◽  
Decision Making Unit ◽  
Efficiency Estimation ◽  
Overall Efficiency ◽  
And Performance ◽  
The Right ◽  
The Impact

Purpose This paper aims to apply a new approach for resource sharing and efficiency estimation of subunits in the presence of non-discretionary factors and partial impacts among inputs and outputs in the data envelopment analysis (DEA) framework. Design/methodology/approach First, inspired by the Imanirad et al.’s model (2013), the authors consider that each decision-making unit (DMU) may consist of several subunits, that each of which can be affected by non-discretionary inputs. After that, the Banker and Morey’s model (1996) is used for modeling non-discretionary factors. For measuring performance of several subunits, which can be considered as DMUs, the aggregate efficiency is suggested. At last, the overall efficiency is computed and compared with each other. Findings One of the important features of proposed model is that each output in this model applies discretionary input according to its need; therefore, the result of this study will make it easier for the managers to make better decisions. Also, it indicates that significant predictions of the development of the overall efficiency of DMUs can be based on observing the development level of subunits because of the influence of non-discretionary input. Therefore, the proposed model provides a more reasonable and encompassing measure of performance in participating non-discretionary and discretionary inputs to better efficiency. An application of the proposed model for gaining efficiency of 17 road patrols is provided. Research limitations/implications More non-discretionary and discretionary inputs can be taken into consideration for a better analysis. This study provides us with a framework for performance measures along with useful managerial insights. Focusing upon the right scope of operations may help out the management in improving their overall efficiency and performance. In the recent highway maintenance management systems, the environmental differences exist among patrols and other geotechnical services under the climate diverse. Further, in some cases, there might exist more than one non-discretionary factor that can have different effects on the subunits’ performance. Practical implications The purpose of this paper was to measure the performance of a set of the roadway maintenance crews and to analyze the impact of non-discretionary inputs on the efficiency of the roadway maintenance. The application of the proposed model, on the one hand, showed that each output in this model uses discretionary input according to its requirement, and on the other hand, the result showed that meaningful predictions of the development of the overall efficiency of DMUs can be based on observing the development level of subunits because of the impact of non-discretionary input. Originality/value Providing information on resource sharing by taking into account non-discretionary factors for each subunit can help managers to make better decisions to increase the efficiency.

scholarly journals An empirical study of oil and gas value chain agility in the UAE

2018 ◽  
Vol 25 (9) ◽  
pp. 3541-3569 ◽  
Author(s):  
Ala Shqairat ◽  
Balan Sundarakani
Keyword(s):  
Supply Chain ◽  
United Arab Emirates ◽  
Value Chain ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Value Chains ◽  
Study Region ◽  
Content Type ◽  
Moderate Effect ◽  
The Impact

Purpose The purpose of this paper is to investigate the agility of oil and gas value chains in the United Arab Emirates (UAE) and to understand the impact of implementing supply disruption (SD) strategies, outsourcing strategies (OS) and management strategies (MS) on oil and gas value chain agility (VCA). The results can support the oil and gas industry across the UAE to build resilience in the value chain. Design/methodology/approach The research design consists of a comprehensive literature review, followed by questionnaire-based survey responses of 106 participants and comprehensive statistical analysis, thus validate the developed theoretical framework and contribute to both practical and methodological approaches. Findings The findings indicate that oil and gas value chain in the UAE has moderate a significant degree of SD, when OS in place that are synchronized with the overall MS. Among the hypotheses developed, two were accepted thus warranting both SD strategies (r=+0.432) and MS (r= +0.457) found to have a positive moderate effect on VCA. The third hypothesis was rejected by revealing OS (r=+0.387) found to have a positive moderate relationship with VCA. Therefore, implementation of all three strategies has a positive moderate effect on the agility of the value chain and, therefore, supports to sustain competitive position. Research limitations/implications Some of the limitations of this research include the geographic coverage of the study region and other methodological limitation. Practical implications The research provides guidance for oil and gas supply chain managers to better understand the critical factors that impact and determine VCA. The paper also describes relevant strategies that should be taken into consideration by these managers in order to build their agile value chains. Social implications The research contributes to the social dimensions of supply chain sustainability of how resilient is the oil and gas value chain during uncertain conditions, so that it can respond to uncertain changes in order to contribute to corporate social responsibility. Originality/value This research is the first of its kind in the UAE region to assess the link between dimensions of agile value chain, OS, SD strategies and MS primarily from the Emirates of Abu Dhabi and Dubai.

scholarly journals Effect of Grid Instability on Power Generation System's Reliability

2020 ◽  
pp. 27-37
Author(s):  
Joseph Benedict Bassey ◽  
Isaac F. Odesola
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Failure Rate ◽  
System Reliability ◽  
Power Distribution ◽  
Power Plants ◽  
Time To Failure ◽  
Generation System ◽  
Reliability Indices ◽  
Mean Time

Aims: Reliability assessment of power generation system may be performed with the concept of system adequacy, security or both. Grid being a major component in the power distribution chain is seen to have some influence on the state of the generation system reliability because of the perturbation that may arise from it. In this study, the generation system reliability is evaluated using both the system adequacy and security concept. Study Design: To capture the system security problems attributed to grid disturbance, the generation system is structured into two component systems (1 - generation component and 2 - transmission component) with a series arrangement. Methodology: The reliability indices such as, mean time to failure, mean time to repair, failure rate and repair rate are assessed on component bases and with respect to the entire generation system. Results: The effect of failure rate of the transmission component on the entire generation system failure rate was evaluated as 66.25%, 55.55%, 33.33%, 55.00% and 35.72% in year 2013, 2014, 2017 2018 and 2019 respectively for FIPL Power Plant and 52.94%, 82.35%, 61.38% and 100% effect was evaluated in the year 2016, 2017, 2018 and 2019 respectively for GT5 of Omoku Power Plant. Conclusion: These results showed that there is a significant influence of grid disturbances on the reliability state of the two gas turbine power plants in Nigeria. Measures on possible reliability state improvement of the power generation systems were suggested to include training and retraining of technical personnel on the management of major equipment in the generation and transmission stations. 

Natural resource governance, accountability and legitimising propensity: insights from Ghana's oil and gas sector

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Emmanuel Asare ◽  
Bruce Burton ◽  
Theresa Dunne
Keyword(s):  
Natural Resource ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Resource Discovery ◽  
Legitimacy Theory ◽  
Structured Interviews ◽  
Content Type ◽  
Resource Governance ◽  
Wide Range ◽  
The Impact

PurposeThis study explores Ghanaian views about accountability discharge by firms and government in the context of the nation's newly discovered oil and gas resources. The research focusses on a range of issues relating to stakeholder interaction, communication flows and the impact of decision-making on Ghanaian lives, as perceived by individuals on the ground.Design/methodology/approachThe paper adapts elements of legitimacy theory to interpret the outcome of a series of semi-structured interviews with members of key accountee and accountor groups including citizens and representatives of the state and private firms in the oil and gas industry in Ghana.FindingsThe results indicate that rather than attempting to effect substantive accountability discharge, Ghana's government and oil and gas firms employ a wide range of legitimation strategies despite the apparently complete absence of the accountee power normally seen as driving the need for social contract repair.Research limitations/implicationsThe findings suggest that accountability discharge in Ghana is cursory at best, with several legitimising strategies in evidence. The representatives from state institutions appear to share some of the concerns, suggesting that the problems are entrenched and will require robust enforcement of a strengthened regulatory approach to effect meaningful change.Originality/valueThis paper contributes to the literature on the discharge of institutional accountability by building on earlier conceptualisations of legitimacy theory to explore perceptions around a recent natural resource discovery. The analysis highlights grave concerns regarding the behaviour of state and corporate actors, one that runs counter to sub-Saharan African tradition.

scholarly journals Finding the right management approach in independent hotels

2019 ◽  
Vol 31 (7) ◽  
pp. 2862-2883 ◽  
Author(s):  
Alireza Nazarian ◽  
Peter Atkinson ◽  
Pantea Foroudi ◽  
Karen Dennis
Keyword(s):  
Leadership Style ◽  
Structural Equation ◽  
Management Approach ◽  
Snowball Sampling ◽  
Content Type ◽  
Organisational Effectiveness ◽  
Independent Hotels ◽  
The Right ◽  
Reward Mechanism ◽  
The Impact

Purpose This study aims to identify factors that managers can influence to improve effectiveness by examining the relationship between leadership and effectiveness in small and medium-sized independent hotels. Design/methodology/approach In total, 272 valid questionnaires were collected from managers of 83 small and medium-sized independent hotels in the Netherlands by using selective and snowball sampling techniques. A two-stage structural equation modelling approach was used to test the hypotheses. Findings Surprisingly, in contradiction to previous studies, neither transactional nor transformational leadership had a direct effect on organisational effectiveness. Instead, the effect was through the intervening variables of ability to acquire resources and reward mechanisms. Research limitations/implications The contradiction between this and previous studies may be due to the fact that constructs used in this study do not have the universal applicability that is customarily assumed and further investigation is needed. Practical implications This study suggests that managers in this type of hotel, first, should be adaptable in their leadership style and not rely on transactional leadership alone; second, managers must pay attention to resource acquisition; and third, managers must retain staff by using the right reward mechanism. Originality/value This study contributes to the literature of leadership and effectiveness in small and medium-sized independent hotels by being the first to focus on the impact of ability to acquire resources and reward mechanism. It also makes an important contribution to the growing body of hospitality literature that probes the supposed universal validity of organisational studies’ constructs.

Impact of bookshelf locations using eye-tracking methodology

2020 ◽  
Vol 41 (8/9) ◽  
pp. 617-629
Author(s):  
Sho Sato ◽  
Yukari Eto ◽  
Kotomi Iwaki ◽  
Tadashi Oyanagi ◽  
Yu Yasuma
Keyword(s):  
Eye Tracking ◽  
User Behavior ◽  
Public Library ◽  
Gaze Behavior ◽  
Content Type ◽  
User Behaviors ◽  
Significant Relationships ◽  
Vertical Location ◽  
The Right ◽  
The Impact

PurposeThis study aimed to understand better the user gaze behavior on bookshelves using eye-tracking technology.Design/methodology/approachAn eye-tracking experiment in a public library with 11 participants was performed. The impact of vertical shelf location of books on the number of times the books are looked at, the impact of horizontal location and the relationship between user behavior and location impact were examined by the findings.FindingsThe results showed that the vertical location of books has a significant impact on the number of times the books are looked at. More than 80% of the time spent looking at bookshelves was spent on books on the top to fourth rows. It was also revealed that the horizontal location of books has a little impact. Books located on the left side of shelves will be looked at significantly more often than those on the right side. No significant relationships between type of user behaviors and location impact were observed.Originality/valueThe study explored the impact of the vertical location of books on time spent looking at bookshelves using eye-tracking methodology. Few published studies do such experiments to address user gaze behavior on bookshelves. The study explored that the vertical location of books has a great impact, and horizontal location has a little impact on user gaze behavior.

Step-exchange strategy for balance control of a walking biped under a lateral impact

2014 ◽  
Vol 41 (5) ◽  
pp. 456-464
Author(s):  
Yeoun-Jae Kim ◽  
Joon-Yong Lee ◽  
Ju-Jang Lee
Keyword(s):  
External Force ◽  
Balance Control ◽  
Biped Robot ◽  
Conservation Equation ◽  
Hill Climbing ◽  
Lateral Impact ◽  
Content Type ◽  
Double Support ◽  
The Right ◽  
The Impact

Purpose – This paper aims to present a step-exchange strategy for balance control of a walking biped robot when a lateral impact acts suddenly. A step-out strategy has been recently proposed for balance control when an unknown lateral force acts to a biped robot during walking. This step-out strategy causes a robot to absorb the impact kinetic energy and efficiently maintain balance without falling down. Nevertheless, it was found that the previous strategies have drawbacks that the two foots should always be on the ground (double-support mode) after being balanced and the authors think it is difficult to continue walking after being balanced. Unlike the existing balance strategies, the proposed step-exchange strategy is to not only maintain balance but also to lift one leg in the air (single-support mode) after being balanced so that it is easy for a biped robot to keep walking after being balanced. Design/methodology/approach – In the proposed step-exchange strategy, forward Newton–Euler equation, angular momentum and energy conservation equation were derived. Hill-climbing algorithm is utilized for numerically finding a solution. To verify the proposed strategy, a biped robot by Open Dynamics Engine was stimulated, and experiments with a real biped robot (LRH-1) were also conducted. Findings – The proposed step-exchange strategy enables a walking biped robot under a lateral impact to keep balance and to keep a single-support mode after exchanging a leg. It is helpful for a biped robot to continue walking without any stop. It is found that the proposed step-exchange strategy can be applicable for maintaining balance even if a biped robot is moving. Even though this proposal seems immature yet, it is the first attempt to exchange the supporting foot itself. This strategy is very straightforward and intuitive because humans are also likely to exchange their supporting foot onto the opposite side when an unexpected force is acting. Research limitations/implications – The proposed step-exchange strategy described in this paper can be applicable in the situation when the external force is applied in the +Y direction, the left leg is the swing leg and the right leg is the stance leg, or it can also be applicable in the situation when the external force is applied in −Y direction, the right leg is the swing leg and the left leg is the stance leg (Figure 2 for ±Y force direction). If an impact force acts to the side of the swing leg, the other step-exchange strategy is needed. The authors are studying this issue as a future work. Originality/value – The authors have originated the proposed step-exchange strategy for balance control of a walking biped robot under lateral impact. The strategy is genuine and superior in comparison with the state-of-the-art strategy because not only can a biped robot be balanced but it can also easily continue walking by using the step-exchange strategy.

Multi-objective mathematical model based on fuzzy hybrid multi-criteria decision-making and FMEA approach for the risks of oil and gas projects

2020 ◽  
Vol 18 (6) ◽  
pp. 1997-2016
Author(s):  
Mohammad Khalilzadeh ◽  
Rose Balafshan ◽  
Ashkan Hafezalkotob
Keyword(s):  
Decision Making ◽  
Oil And Gas ◽  
Programming Model ◽  
Multi Criteria Decision Making ◽  
Content Type ◽  
Multi Objective ◽  
Response Strategies ◽  
Fuzzy Environment ◽  
Comprehensive Framework ◽  
Grey Relational

Purpose The purpose of this study is to provide a comprehensive framework for analyzing risk factors in oil and gas projects. Design/methodology/approach This paper consists of several sections. In the first section, 19 common potential risks in the projects of Pars Oil and Gas Company were finalized in six groups using the Lawshe validation method. These factors were identified through previous literature review and interviews with experts. Then, using the “best-worst multi-criteria decision-making” method, the study measured the weights associated with the performance evaluation indicators of each risk. Consequently, failure mode and effects analysis (FMEA) and the grey relational analysis (GRA)-VIKOR mixed method were used to rank and determine the critical risks. Finally, to assign response strategies to each critical risk, a zero-one multi-objective mathematical programming model was proposed and developed Epsilon-constraint method was used to solve it. Findings Given the typical constraints of projects which are time, cost and quality, of the projects that companies are often faced with, this study presents the identified risks of oil and gas projects to the managers of the oil and gas company in accordance with the priority given in the present research and the response to each risk is also suggested to be used by managers based on their organizational circumstances. Originality/value This study aims at qualitative management of cost risks of oil and gas projects (case study of Pars Oil and Gas Company) by combining FMEA, best worst and GRA-VIKOR methods under fuzzy environment and Epsilon constraints. According to studies carried out in previous studies, the simultaneous management of quantitative and qualitative cost of risk of oil and gas projects in Iran has not been carried out and the combination of these methods has also been innovated.

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