Optimization of reliability and maintenance of liquefaction system on FLNG terminals using Markov modelling

2014 ◽  
Vol 31 (3) ◽  
pp. 293-310 ◽  
Author(s):  
Samer Gowid ◽  
Roger Dixon ◽  
Saud Ghani

Purpose – The purpose of this paper is to optimize system redundancy and maintenance intervals of a propane pre-cooled mixed refrigerant (C3MR) liquefaction process on floating liquefied natural gas (FLNG) export platforms. Design/methodology/approach – The reliability modeling is based on the time-dependent Markov approach. Four different system options are studied, with various degree of redundancy. Failures in the liquefaction system usually lead to shutdown the whole LNG production plant. The associated shutdown cost is compared with the cost of introducing redundancy and the cost of onboard maintenance. To ensure a high profitability, a model for maintenance optimization is utilized and applied to the main unit of the C3MR liquefaction system to minimize the onboard maintenance cost. Findings – The results indicated that the introduction of a second liquefaction system (as a standby unit) is the best option for liquefaction plant in terms of reliability and cost. This will substantially reduce the unavailability from 14.7 to 2.19 percent of the total operational hours. Based on the presented system configuration, the annual system profit will increase by 180 million USD if the redundancy is implemented on FLNG export ships. The optimum maintenance intervals of major process components are also calculated to minimize the total cost of maintenance. Originality/value – The originality of this paper lies within the context in investigating the reliability of the C3MR liquefaction system on LNG floating export terminals using Markov modeling for the first time.

2018 ◽  
Vol 35 (3) ◽  
pp. 762-778 ◽  
Author(s):  
Katerina Gotzamani ◽  
Andreas Georgiou ◽  
Andreas Andronikidis ◽  
Konstantina Kamvysi

Purpose The purpose of this paper is to provide an enhanced version of quality function deployment (QFD) that captures customers’ present and future preferences, accurately prioritizes product specifications and eventually translates them into desirable quality products. Under rapidly changing environments, customer requirements and preferences are constantly changing and evolving, rendering essential the realization of the dynamic role of the “Voice of the Customer (VoC)” in the design and development of products. Design/methodology/approach The proposed methodological framework incorporates a Multivariate Markov Chain (MMC) model to describe the pattern of changes in customer preferences over time, the Fuzzy AHP method to accommodate the uncertainty and subjectivity of the “VoC” and the LP-GW-AHP to discover the most important product specifications in order to structure a robust QFD method. This enhanced QFD framework (MMC-QFD-LP-GW-Fuzzy AHP) takes into consideration the dynamic nature of the “VoC” captures the actual customers’ preferences (WHATs) and interprets them into design decisions (HOWs). Findings The integration of MMC models into the QFD helps to handle the sequences of customers’ preferences as categorical data sequences and to consider the multiple interdependencies among them. Originality/value In this study, a MMC model is introduced for the first time within QFD, in an effort to extend the concept of listening to further anticipating to customer wants. Gaining a deeper understanding of current and future customers’ preferences could help organizations to design products and plan strategies that more effectively and efficiently satisfy them.


2015 ◽  
Vol 32 (2) ◽  
pp. 144-155 ◽  
Author(s):  
Andrea Chiarini

Purpose – The purpose of this paper is to investigate whether there are differences in terms of the effect of the ISO 9001 non-conformity process on the cost of poor quality in different sectors. In particular, to investigate the effect on six sectors of companies which manufacture their products mainly through machines and plant (i.e. capital-intensive companies). An additional aim is to understand what the reasons for these differences are and why ISO 9001 has limitations in reducing the different categories of costs of poor quality. Design/methodology/approach – The paper is based on a questionnaire administered to a sample of 42 companies divided into six different sectors: chemical, pharmaceutical, mechanical, food, ceramic and steel. Respondents were asked to give a percentage score for the contribution the ISO 9001 non-conformity process makes to the reduction in total cost of poor quality and to its categories: scrap, rework, machine stoppage, re-inspections, rejected products and recall cost. A one-way Anova test was applied to the means of the percentage scores to determine whether there are differences between the means of the total cost of poor quality and its categories. Qualitative comments and suggestions from the companies provided information that helped explain the reasons for such differences. Findings – The results of the research show that there is no difference within and between the sectors in the means of the total cost of poor quality and scrap cost, whereas there are significant differences in the means of the other costs of poor quality between the six sectors. The ISO 9001 non-conformity process has limitations in reducing the costs of poor quality and suggestions concerning the limitations of ISO 9001 in the Research and Development process emerge. Research limitations/implications – The generalizability of the research findings is limited because of the use of just six sectors of capital-intensive companies. Further research about differences in different sectors is needed. Practical implications – The implications of this research are useful for consultants and managers who want to understand what the limitations of the ISO 9001 non-conformity process are on the cost of poor quality in the six sectors. The findings clearly show how, together with ISO 9001, they should take into account other improvement processes such as periodic maintenance and revamping. Originality/value – The paper discusses in a quantitative way and for the first time the effects of the ISO 9001 non-conformity process on the cost of poor quality.


2020 ◽  
Vol 10 (2) ◽  
pp. 97-123 ◽  
Author(s):  
Amin Mahmoudi ◽  
Mehdi Abbasi ◽  
Xiaopeng Deng ◽  
Muhammad Ikram ◽  
Salman Yeganeh

PurposeSelecting a suitable contract to outsource construction projects is an ongoing concern for project managers and organizational directors. This study aims to propose a comprehensive model to manage the risks of outsourced construction project contracts.Design/methodology/approachTo employ the proposed model, firstly, the types of contracts and risks in the organization should be identified, then, to prioritize the contracts, the identified risks are considered as criteria. After receiving the experts' opinions, the best–worst method (BWM) integrated with grey relation analysis (GRA) method was used to prioritize the contracts. BWM and GRA are multi-criteria decision-making methods with different approaches and applications. In the current study, BWM has been employed to calculate the weights of criteria because it has better performance than other methods such as the analytic hierarchy process (AHP). After calculating the weights of criteria, the GRA method has been utilized for ranking the alternatives.FindingsAccording to the results obtained from the case study, the cost plus award fee contract is the most suitable alternative for outsourcing construction projects. The proposed methodology can be practically applied through different types of the projects such as construction or “engineering, procurement and construction”.Originality/valueTo the best of our knowledge, this is the first time a conceptual model has been proposed to select an appropriate contract for construction projects. Also, for the first time, the BWM integrated with GRA method has been used to prioritize project contracts based on the potential risks. The proposed model can contribute to project managers for selecting a suitable contract with the least risk in construction projects.


2014 ◽  
Vol 32 (3) ◽  
pp. 308-321 ◽  
Author(s):  
Ling-Feng Hsieh ◽  
Jiung-Bin Chin ◽  
Mu-Chen Wu

Purpose – The aim of this paper is to construct a model of cost efficiency and service effectiveness for a university e-library to allocate e-resources cost and to attain quality of service enhancement and cater to the needs of readers with existing e-resources. Design/methodology/approach – The paper establishes an assessment model for the cost efficiency and service effectiveness of a university e-library in Taiwan. It then proceeds with an empirical study and analysis of related data collected from e-libraries of 16 universities. A discussion of the results of the study and suggestions for the adjustment of the university e-libraries follows. Findings – The paper combines two models of cost efficiency and service effectiveness for the first time to analyze and consider the output results created by the input cost of university e-libraries in Taiwan and their utilization by readers. Originality/value – The paper builds a figure for the relationship of e-library cost efficiency and service effectiveness at 16 universities in Taiwan and then divides it into four types.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2059-2059
Author(s):  
Brian L. Burnette ◽  
Angela Dispenzieri ◽  
Shaji Kumar ◽  
Jeff Sloan ◽  
Jon Tilburt ◽  
...  

Abstract Abstract 2059 Introduction: Two randomized trials have demonstrated a benefit in progression free survival (PFS) of 18–20 mofor maintenance treatment with lenalidomide after auto-PBSCT for multiple myeloma (MM). Although results on survival benefit are conflicting and quality of life (QOL) data is lacking, some have begun to recommend maintenance. No study has evaluated patient perceptions of maintenance. We conducted a systematic survey of MM patients (pts) regarding what constitutes a meaningful benefit that would make burdens of maintenance (toxicity and cost) acceptable. Methods: We mailed a brief self-administered survey in 3 waves to 1159 consecutive living pts evaluated at Mayo Clinic. The survey provided background on the standard of care for MM in transplant eligible pts and data on maintenance. Pts were asked to estimate the magnitude of OS benefit that would be acceptable for varying degrees of toxicity and cost. Results: Of the 1159 surveys sent, 886 pts (83.2%) responded, including 150 notifying us of a decision not to participate. 736 pts returned a completed survey (66% raw response rate). (56%) male, 407 (55%) had undergone auto-PBSCT, 467 (63%) had discussed maintenance with a physician, and 9 (1%) pts had received no treatment. 10% of pts had MM for 3–12 mo, 14% for 1–2 yr, 13% for 2–3 yr, 20% for 3–5 yr, 44% for 5 yr or more. Pt age: 4% 18–49 yr, 24% 50–59 yr, 40% 60–69 yr, 27% 70–79 yr, and 6% >80 yrs. The most worrisome potential toxicity was identified as peripheral neuropathy by 27% of pts, cytopenias by 24%, LE DVT 20%, fatigue 15%, nausea 8%, diarrhea/constipation 7%. In response to a question about whether they would choose maintenance if there was a PFS benefit but no improvement in OS, 92% would opt for maintenance if it were known to cause mild toxicity, while 77% would opt for maintenance despite moderate toxicity. Subsequent questions included cost and toxicity considerations and required pts to identify minimum acceptable duration of OS benefit to estimate more precisely a meaningful clinical benefit. If treatment was free, had no toxicity, and the OS benefit was 1 yr or less, 49% would choose maintenance (see Figure). In the same scenario, if toxicities were mild, the proportion of pts who choose maintenance was similar (46%). If pts experienced moderate toxicity, 42% choose maintenance. With rising financial burden (out-of-pocket) and toxicity, the proportion of pts who choose maintenance declined (see Table). For example, if the cost was $25/mo, mild toxicity experienced, and the OS benefit was one year or less, 46% would choose maintenance, while 39% of pts would choose maintenance if it cost $250/month and there was moderate toxicity. If maintenance cost $10,000/mo and was associated with mild or moderate toxicity, 18% and 17% of pts would choose treatment, respectively. Conclusions: For the first time, we have described the broad range of patient perspectives regarding trade-offs in the treatment of MM with maintenance therapy. We found that willingness to be treated with maintenance declined when actual benefits were provided in concrete numeric terms compared with a general statement of PFS benefit. The discrepancy between the 92% of pts choosing to undergo maintenance if free and mild toxicity when there is a PFS benefit but no OS benefit, compared to 49% of pts choosing maintenance if free, mild toxicity, and associated with an OS benefit of 1 yror less; suggests pts have difficulty understanding the concept of PFS. We also found that the magnitude of benefit required to consider maintenance was affected by cost and toxicity. In our experience, pts typically incur a cost of approximately $25/mo and experience mild toxicity. In this study, nearly half (46%) of such pts would opt for maintenance if the OS benefit was 1 year or less while only 33% of pts would opt for maintenance if the OS benefit was 6 months or less. Our data implies that good care in MM requires detailed conversations about each and every patient's priorities and expectations prior to making recommendations for or against such treatments. Disclosures: No relevant conflicts of interest to declare.


2019 ◽  
Vol 33 (2) ◽  
pp. 335-358
Author(s):  
Dorota Kuchta ◽  
Radoslaw Rynca ◽  
Dariusz Skorupka ◽  
Artur Duchaczek

Purpose In the literature, there are many methods that can be helpful in strategic management of universities. Some of them are related to the aspect of sustainability, in terms of balancing the level of fulfillment of different, often conflicting objectives, which must be considered when building strategies. These methods include product/service portfolio ones. However, their use is often intuitive and detached from the quantitative aspects of management. The purpose of this paper is to present a proposal of the modification of the portfolio methods through the use of one of discrete optimization problems, namely, the multiple knapsack problem. The proposal is applied to a selected university. The results are presented and discussed. Design/methodology/approach The research methodology consists in a conceptual work: combining non-quantitative portfolio methods used in strategic management and the quantitative multiple knapsack problem. The analogy is established between a market sector (capacity) and a knapsack (capacity), a university department value and an object value, the university improvement budget and a knapsack, an object cost and an improvement measure cost. Then, the case study is used to conduct an initial validation of the proposed approach. Findings A quantitative model for strategic management of university as a whole or university departments is proposed. It allows to plan and control the application of improvement measures, allowing the university units to take on a better position in the educational market. It has been initially applied to a small university. Research limitations/implications The model requires much more real-world case studies. Also, it will usually be difficult to establish the cost of running individual university units as well as the cost of corrective measures. The capacity of knapsacks – here of market sectors – will also be difficult to calculate. The method to be used here is activity-based costing, but it will not solve all the problems immediately, as its practical application is difficult. Practical implications The proposed model will allow to plan and evaluate strategic changes of university as a whole and its units’ position using quantitative values and to consider various strategic scenarios. Social implications In order to establish the data necessary to construct the model, various stakeholders will have to cooperate (the university promotion department, the accounting representatives, the student and industry representatives etc.), probably for the first time. Such cooperation will improve the university position even if the model itself will not be able to be applied immediately. Originality/value The link between portfolio methods and a quantitative optimization method for university management purposes has been established in the paper for the first time in the literature.


2018 ◽  
Vol 45 (2) ◽  
pp. 401-410 ◽  
Author(s):  
Felippe Clemente ◽  
Viviani Silva Lírio

Purpose The purpose of this paper is to use the instrumental game theory to understand the behavior of the front agents tax evasion and tax authority in Brazil. Design/methodology/approach In order to analyze the taxpayer’s behavior before the Brazilian tax system and tax actions aimed at reducing tax evasion, the authors developed a theoretical model based on the payoffs of Graetz et al. (1986) and increased with situations proposed by Siqueira (2004), Lipatov (2006) and Oliveira (2011). Findings Considering the cases with and without specialists, the main results show that in high dropout situation, penalize taxpayers with high fines or deprivations of liberty may not be as effective. Another result of the analysis is that the audit and inspection costs played an important role in driving the equilibrium system. Research limitations/implications One limitation of this study is to consider how the exogenous tax authorities earnings (Federal Revenue of Brazil and Federal Police) and not as a function of the goals and certain enforcement policies for each public body. Practical implications The authors suggest the following policy: investing in tax inspectors and unbureaucratic the authorities of the cost structure become a more effective tool to combat non-compliance with tax obligations that the intensity of the penalties imposed by the act of evading. Originality/value This paper contributes to the literature insofar as it models for the first time, using game theory, the behavior of the evading agent and the tax authority in Brazil.


2020 ◽  
Vol 28 (4) ◽  
pp. 639-666
Author(s):  
Medhat N. El Guindy ◽  
Nadia Sbei Trabelsi

Purpose This paper aims to investigate the impact of International Financial Reporting Standards (IFRS) adoption on audit and non-audit fees in the UK setting. The study investigates whether UK firms adopting IFRS for the first time or reporting under IFRS, in general, are being charged higher audit and non-audit fees and whether this impact is conditional on audit firm size and tenure. Design/methodology/approach Using empirical data for UK listed firms from 2003-2007, the paper uses a regression model that explains audit and non-audit fees by independent variables measuring auditors’ and auditees’ characteristics including IFRS adoption and reporting. Additional regressions with interaction terms were performed to test the hypothetical conditional impact of auditor size and audit firm tenure on the above-mentioned association. Findings Audit and non-audit fees increase significantly for companies adopting IFRS for the first time and this increase is persistent during later years. In addition, results suggest that both Big four and non-Big four auditors charge higher audit and non-audit fees to their clients adopting or reporting under IFRS in a similar manner. Furthermore, findings indicate that audit firms increase audit and non-audit fees for old and new clients using IFRS which suggests no low-balling effect is detected. Research limitations/implications Results reported in this study provide insights to regulators in jurisdictions similar to the UK regarding the cost of IFRS adoption which includes higher audit and non-audit fees imposed by both Big four and non-Big four audit firms. In addition, this study argues, to some extent, against the notion that auditors may charge lower fees in the early years of the audit engagement to win new audit clients. Originality/value To the best of the knowledge, the findings are unique at two levels. First, the paper provides evidence on the cost of using IFRS in the UK jurisdiction which was not explored by previous research. Second, the paper investigates the potential conditional effect of auditor size and audit tenure on the association between IFRS adoption and auditors’ fees.


2017 ◽  
Vol 34 (7) ◽  
pp. 2396-2408 ◽  
Author(s):  
Fang Shutian ◽  
Zhao Tianyi ◽  
Zhang Ying

Purpose This study aims to predict the construction cost in China, the authors purposed a fused method. Design/methodology/approach The authors extracted 22 factors which may influence the cost and performed the correlation analysis with cost. They chose the highest 10 factors to predict cost by the fused method. The method fused the Kalman filter with least squares support vector machine and multiple linear regression. Findings Ten factors which affect the cost most were found. The construction cost in China can be predicted by the presented method precisely. The statistical filter method could be used in the field of construction cost prediction. Research limitations/implications The construction cost and construction interior factors are a business secret in China. So, the authors only collected 24 buildings’ data to perform the experiments. Practical implications There is no standard and precise method to predict construction cost in China, so the presented method offers a new way to judge the feasibility of projects and select design schemes of construction. Originality/value The authors purposed a new fused method to predict construction cost. It is the first time that the statistical filtering method was used in this field. The effectiveness was verified by the experiments. Ten factors which have a high relationship with construction cost were found.


2020 ◽  
Vol 30 (11) ◽  
pp. 4837-4863
Author(s):  
Rainald Löhner ◽  
Harbir Antil

Purpose The purpose of this study is to determine the possibility of an accurate assessment of the spatial distribution of material properties such as conductivities or impedances from boundary measurements when the governing partial differential equation is a Laplacian. Design/methodology/approach A series of numerical experiments were carefully performed. The results were analyzed and compared. Findings The results to date show that while the optimization procedure is able to obtain spatial distributions of the conductivity k that reduce the cost function significantly, the resulting conductivity k is still significantly different from the target (or real) distribution sought. While the normal fluxes recovered are very close to the prescribed ones, the tangential fluxes can differ considerably. Research limitations/implications At this point, it is not clear why rigorous mathematical proofs yield results of convergence and uniqueness, while in practice, accurate distributions of the conductivity k seem to be elusive. One possible explanation is that the spatial influence of conductivities decreases exponentially with distance. Thus, many different conductivities inside a domain could give rise to very similar (infinitely close) boundary measurements. Practical implications This implies that the estimation of field conductivities (or generally field data) from boundary data is far more difficult than previously assumed when the governing partial differential equation in the domain is a Laplacian. This has consequences for material parameter assessments (e.g. for routine maintenance checks of structures), electrical impedance tomography, and many other applications. Originality/value This is the first time such a finding has been reported in this context.


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