| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Caretta, Martina Angela, et al.
(författare)
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Water
- 2022
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Ingår i: Climate Change 2022: Impacts, Adaptation and Vulnerability : Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change - Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Kansal, Yogita, et al.
(författare)
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Fixing of Faults and Vulnerabilities via Single Patch
- 2018
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Ingår i: Quality, IT and Business Operations. - Singapore : Springer. - 9789811055768 - 9789811055775 ; , s. 175-190
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Bokkapitel (refereegranskat)abstract
- Users’ demand of reliable software in zero time has made the software development more complex. If software industry fails in fulfilling the demands, then it may undergo big penalties and revenue loss. The developers are pressurized subject to resource constraints provided by the management. Despite such fact, software experiences various validation (testing) processes before its release; faults and vulnerabilities are still left undetected that later lack the quality of the product. The only feasible solution for resisting from the lack after the release of software is patch development. Generally, the patches developed for fixing faults and vulnerabilities are a separate process which requires extra resources that increases the total development cost and time. In this paper, we have proposed a cost framework that solves the problem of optimizing the patch release time with two different approaches. Here, the first approach has considered the release of a single patch that fixes both faults and vulnerabilities jointly. As the severity of vulnerabilities is much higher than the faults, the second approach considered the release of two patches where the first patch has fixed both faults and vulnerabilities jointly and other patch specifically fixed only vulnerabilities. The detailed illustration of the method is presented in the proposed paper. The case study is presented at the end for the validation purpose.
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| 4. |
- Kansal, Yogita, et al.
(författare)
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Prioritizing Vulnerabilities using ANP and Evaluating their Optimal Discovery and Patch Release Time
- 2019
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Ingår i: International Journal of Mathematics in Operational Research (IJMOR). - : InderScience Publishers. - 1757-5850 .- 1757-5869. ; 14:2, s. 236-267
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Tidskriftsartikel (refereegranskat)abstract
- Method for filtering and identifying a vulnerability class that has high probability of occurrence is needed by organisations to patch their software in a timely manner. In this paper, our first step is to filter the most frequently observed vulnerability type/class through a multi-criteria decision making that involves dependency among various criteria and feedback from various alternatives, known as analytic network process. We will also formulate a cost model to provide a solution to the developers facing high revenue debt because of the occurrence of highly exploited vulnerabilities belonging to the filtered group. The main aim of formulating the cost model is to evaluate the optimal discovery and patch release time such that the total developer's cost could be minimised subject to risk constraints. To illustrate the proposed approach, reported vulnerabilities of Google Chrome with high exploitability have been examined at its source level.
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| 5. |
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| 6. |
- Kumar, Saurabh, et al.
(författare)
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Inspection frequency optimization model for degrading flowlines on an offshore platform
- 2008
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Ingår i: International Journal of Reliability, Quality and Safety Engineering (IJRQSE). - 0218-5393. ; 15:2, s. 167-180
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Tidskriftsartikel (refereegranskat)abstract
- Many offshore oil and gas installations in the North Sea are approaching the end of their designed lifetimes. Technological improvements and higher oil prices have developed favorable conditions for more oil recovery from these existing installations. However, in most cases, an extended oil production period does not justify investment in new installations. Therefore cost-effective maintenance of the existing platform infrastructure is becoming very important. In this paper, an inspection frequency optimization model has been developed which can be used effectively by the inspection and maintenance personnel in the industry to estimate the number of inspections/optimum preventive maintenance time required for a degrading component at any age or interval in its lifecycle at a minimum total maintenance cost. The model can help in planning inspections and maintenance intervals for different components of the platform infrastructure. The model has been validated by a case study performed on flowlines installed on the top side of an offshore oil and gas platform in the North Sea. Reliability analysis has been carried out to arrive at the best inspection frequency for the flowline segments under study
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| 7. |
- Chattopadhyay, G., et al.
(författare)
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Estimation of parameter for rail degradation
- 2006
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Ingår i: Condition Monitoring and Diagnostic Engineering Management. - Luleå : Luleå tekniska universitet. - 9789163188060 ; , s. 605-612
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Konferensbidrag (refereegranskat)abstract
- Rail degradation is a significant problem for rail industries. Wear and fatigue comprises major component of rail degradation. It depends on operational conditions such as train speed, axle load, rail-wheel material type, size and profile, track construction, characteristics of bogie type, Million Gross Tonnes (MGT), curvature, traffic type, weather and environmental conditions. Development of prediction model related to those defects leading to rail breaks and/or rail replacements is vital for economic and safe operation of rail services. Estimation of parameter for failure models is necessary for accurate prediction of expected number of rail defects over a period of time based on Million Gross Tonnes (MGT) traffic, operating conditions and maintenance strategies. This paper focuses on collection and analysis of field data for various defects developed in rail track over a period of time for estimation of parameter for models predicting degradation of rails.
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| 8. |
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| 9. |
- Ghodrati, Behzad, et al.
(författare)
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Product support logistics based on product design characteristics and operating environment
- 2003
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Ingår i: Proceedings of the 38th annual International Logistics Conference and Exhibition. - : Society of Logistics Engineers.
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Konferensbidrag (refereegranskat)abstract
- To improve the reliability, maintainability, and supportability (RMS) of a product, it is necessary to understand the factors influencing the product performance. This factors can be user environment, human (operator) aspects like training, and technical characteristics of the product. The environmental conditions in which the equipment is to be operated, such as temperature, humidity, dust, road conditions, maintenance facilities, maintenance crew training, operators' skill, etc, often have considerable influence directly on the product reliability and indirectly on the product supportability characteristics. Thus operating environment should be seriously considered while dimensioning product support and service delivery performance strategies, since it will have an impact on operational and maintenance cost and service quality to provide product support plan in an optimal condition. Spare parts are classified, as a product support items whose availability is important when planned or unplanned maintenance is to be carried out. Forecasting the required support/spare parts based on technical characteristics and operating environmental conditions of a system, is the one of the best ways for optimizing unplanned stoppages. This paper discusses about product support (required spare part) logistics based on product design characteristics and operating environment both for conventional and functional products.
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| 10. |
- Ghodrati, Behzad, et al.
(författare)
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Product support (spare parts procurement) strategy based on reliability characteristics and geographical location
- 2003
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Ingår i: International Conference on Industrial Logistics. - Vaasa : University of Vaasa. - 952476010X ; , s. 222-235
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Konferensbidrag (refereegranskat)abstract
- Product support, which is also referred to after sale service to the product is important for customer because it increases the availability of the product and it assures the expected function of the product in its operational phase. It gets affected by many factors such as - reliability and maintainability characteristics and geographical location of the product. By highlighting the reliability issues and geographical distribution of product in design and manufacturing phases, the product life cycle cost (LCC) can be optimized. One of the important steps in product design is the decision making for design out maintenance (DOM) and/or designs for maintenance (DFM). The DOM alternative leads to produce high reliable, and vice versa, whereas the DFM assure the similar performance with lower reliability. However, the need for product support and spare parts must be considered in both alternatives. The forecasting of required product support and spare parts based on reliability-maintainability characteristics is one approach for the product LCC optimization. Consequently, spare parts inventory management based on geographical distribution and reliability characteristics of the product can be also used as an alternative. This article describes a method to forecast the spare part requirements based on reliability estimation of the existing product under the influence of the product-operating environment. Subsequently the management of the spare parts inventory will be discussed based on the geographical location and required performance of the product.
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| 11. |
- Jena, Jajati K., et al.
(författare)
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Tunnel QRA : Present and Future Perspectives
- 2019
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Ingår i: System Performance and Management Analytics. - Singapore : Springer. - 9789811073229 - 9789811073236 ; , s. 387-403
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Bokkapitel (refereegranskat)abstract
- With the vision of faster in-land transportation of humans and goods, long tunnels with increasing engineering complexities are being designed, constructed and operated. Such complexities arise due to terrain (network of small tunnels) and requirement of multiple entries and exits (network of traffics leading to non-homogenous behaviour). Increased complexities of such tunnels throw unique challenges for performing QRA for such tunnels, which gets compounded due to handful number of experiments performed in real tunnels, as they are costly and dangerous. A combined approach of CFD modelling of scaled down tunnels could be a relatively less resource intensive solution, nevertheless, associated with its increased uncertainties due to introduction of scaling multiplication factors. Further, with the advent of smart system designs and cheap computational cost, a smart tunnel which manages its own traffic of both dangerous goods carriers and other passenger vehicles based on continuously updated dynamic risk estimate, is not far from reality.
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| 12. |
- Kansal, Yogita, et al.
(författare)
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Effort and coverage dependent vulnerability discovery modeling
- 2018
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Konferensbidrag (refereegranskat)abstract
- In this paper, our primary focus is to propose a generalized mathematical model that can discover potential vulnerabilities on the basis of two key factors: operational effort rate and operational coverage rate. Here, the term operational effort rate refers to the proportion of manpower required to discover vulnerabilities. The operational coverage rate refers to the proportion of software covered by the effort in discovering vulnerabilities. It is assumed that the proposed model follows the Non-Homogeneous Poisson process properties thus different distribution are used to formulate multiple cases. To evaluate the operational effort function, exponential and Weibull distribution are used considering coverage rate either to be a constant or logistic. For model validation, a case study of real commercial software data set has been used
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| 13. |
- Kansal, Yogita, et al.
(författare)
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User-dependent vulnerability discovery model and its interdisciplinary nature
- 2017
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Ingår i: Life Cycle Reliability and Safety Engineering. - : Springer. - 2520-1352 .- 2520-1360. ; 6:1, s. 23-29
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Tidskriftsartikel (refereegranskat)abstract
- Software Vulnerability is a broad discipline that cannot be controlled only by the technologies. The holistic framework is required that statistically encompasses the entire security issues of IT organizations regardless of individual projects. Earlier researchers have developed several mathematical models that determined the vulnerabilities trend over time. Besides that, the most common victims of the vulnerabilities i.e., the software buyers or users were addressed theoretically without considering their impact on vulnerability discovery modeling. In this research paper, we examined the vulnerability discovery rate on the basis of potential users of commercial software. Here we propose an interdisciplinary model that highlights the relationship between the vulnerability intensity and the number of users of the software. The numerical illustration based on several real data sets is provided to validate the proposed user-dependent vulnerability discovery model.
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| 14. |
- Kour, Ravdeep, 1981-, et al.
(författare)
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Metaverse for Intelligent Asset Management
- 2022
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Ingår i: 2022 International Conference on Maintenance and Intelligent Asset Management (ICMIAM). - : IEEE.
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Konferensbidrag (refereegranskat)
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| 15. |
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| 16. |
- Kumar, Dhananjay, et al.
(författare)
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Reliability analysis of power transmission cables of electric mine loaders using the proportional hazards model
- 1992
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 37:3, s. 217-222
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Tidskriftsartikel (refereegranskat)abstract
- The proportional hazards model (PHM) is a powerful technique which can be used to investigate the effects of operating environment and the diagnostic variables (covariates) associated with an item on its life length. The effects of two different designs and maintenance on the reliability of a power transmission cable of an electric mine loader is investigated using PHM. The purpose is to illustrate the application of this model in making decisions about selecting the proper material or designing an item to meet the required purpose efficiently. (11 refs.)
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| 17. |
- Kumar, Rajesh, et al.
(författare)
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A conceptual framework for the development of a service delivery strategy for industrial systems and products
- 2004
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Ingår i: Journal of business & industrial marketing. - : Emerald. - 0885-8624 .- 2052-1189. ; 19:5, s. 310-319
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Tidskriftsartikel (refereegranskat)abstract
- Service and product support are increasingly critical elements in the achievement of customer satisfaction and winning new markets. The success of a product support strategy depends on how effectively these services are delivered. The focus of this paper is on performance enhancement through the use of service delivery strategies; critical factors in the marketing of product support and service-related contracts that in turn, foster customer satisfaction, based on industrial systems in a multinational environment Considered in the framework are product design characteristics such as reliability, maintainability, customer's organizational culture and geographical location, for functional as well as conventional products. The paper advocates an increased focus on support to customers within the framework, introduces a modified service gap model and suggests an approach that reduces any gap between expected and required services. An evaluation of service delivery performance is emphasized.
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| 18. |
- Kumar, Rupesh, et al.
(författare)
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Ergonomic and maintainability design issues in mining
- 2009
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Konferensbidrag (refereegranskat)abstract
- Due to confined space and poor illumination in the mine the maintenance activities are difficult to perform which in turn leads to increased down time, cost and injuries. This also influences the productivity of maintenance personnel owing to stresses generated due to increased psychological and physiological demand on them. However, the industry has paid much less attention to the design of the mining machine in initial phase itself with respect to maintainability parameters leading to low productivity, increased maintenance time and increased likelihood of accidents during maintenance and operation of such equipment. The objective of the paper is to present ergonomics factors such as; anthropometery, human sensory, physiological and psychological application in relation to maintainability design issues in mining in order to reduce occupational risk factors and improved maintainability of the mining equipments leading to increased productivity.
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| 19. |
- Kumar, Rupesh, et al.
(författare)
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Ergonomic issues at a railway maintenance workshop
- 2011
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Ingår i: Proceedings of the 24th International Congress on Condition Monitoring and Diagnosis Engineering Management. - : COMADEM International. - 0954130723 ; , s. 1583-1587
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Konferensbidrag (refereegranskat)abstract
- Research on human factors related to railway operation and maintenance has, to an extent, been the neglected branch of transport ergonomics. Despite the numerous reports of ergonomics programs in a variety of industries, no examples of implementing ergonomics interventions in the railway vehicle maintenance workshop have been reported.In this study, a maintenance process at a railway workshop was studied and analyzed with special reference to working posture and maintenance repair time. The working postures of two maintenance personnel were obtained and analyzed using OWAS (Ovako Working Posture Analysis System). From the results, it was clearly indicated that poor working posture was a frequent occurrence during the maintenance activities. It can be concluded that the introduction and implementation of ergonomics principles at the railway maintenance workshop must be considered in order to reduce the poor working postures, maintenance repair time and to improve maintainability and productivity.
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| 20. |
- Kumar, Rajesh, et al.
(författare)
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Implementation and execution of industrial service strategy : a case study from the oil and gas industry
- 2006
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Ingår i: Journal of Quality in Maintenance Engineering. - : Emerald. - 1355-2511 .- 1758-7832. ; 12:2, s. 105-117
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The purpose of the paper is to discuss the complex issues, obstacles and factors that can have a significant role and influence on the implementation and execution of a performance-based industrial service strategy. Design/methodology/approach - A case study has been performed the oil and gas industry which maps the issues, challenges and opportunities in the process of implementing and executing a performance-based service strategy. Findings - The study identifies differences in practice with respect to conventional as compared to performance-based contracts. Furthermore, performance factors (i.e. cost drivers, performance killers and critical success factors) of the service strategy implementation and execution process are discussed in relation to the oil and gas industry in the North Sea. A performance-based service strategy needs to be upgraded, modified and customized based on performance measurements, as well as needs, wants and preferences of the involved parties during the contract period. Practical implications - The findings and discussions will help service strategy developers, implementers and executors to recognize the importance of a focused service strategy development process for industrial services. Moreover, the paper will guide developers, implementers and executors to decide about factors that need to be considered. Originality/value - The framework discussed can be used to develop a performance-based service strategy. The results of the research will ease the process of understanding and defining the implementation and execution process of a strategy by presenting the possible performance factors in advance.
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| 21. |
- Kumar, Rupesh, et al.
(författare)
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Improvement of performance of oil and gas production facilities in arctic regions by applying human factors/ergonomic principles at the design phase
- 2009
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Ingår i: Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions.
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Konferensbidrag (refereegranskat)abstract
- The system with a low level of reliability of being deployed in a cold climate often needs special and additional focus on maintainability characteristics in order to achieve the higher level of productivity, system availability and safety. Therefore, the maintainability issue is critical for the successful and effective operation of oil and gas installations in the Arctic environment as the working conditions are made very difficult by low temperature, ice, short period of daylight and lack of support facilities. Furthermore, the maintenance tasks or maintainability in the Arctic region is heavily influenced by the design of the task and the design of the equipment being maintained. The risk of human error in the Arctic environment is very high and about 80% of offshore accidents are caused by humans, with 64% occurring during operations. Morover, human factors/ergonomics is now recognized as a major contributor to operational safety, loss prevention and optimizing system performance in the oil and gas industries. Therefore, the study of human factor and reliability is essential to ensure the safe and reliable operation of industrial plant and systems which involve human operators. Human factors' integration aims to 'design-in' the humans into plant and system design, taking account of their capabilities and limitations. This can lead to significant savings through appropriate manning levels, maintainable plant, reduced rework and user-friendly facilities and systems.The objective of this paper is to explore potential risk factors especially in Arctic conditions with a view to how human factors/ergonomic principles can help to reduce risk factors and increase maintainability of the oil and gas industry. In this paper, the starting point is the offshore oil and gas industry, but the methodology and discussion are to a large extent general and could also be applied in the other industries.
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| 22. |
- Kumar, Rupesh, et al.
(författare)
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Improving maintainability in extreme cold climatic conditions
- 2012
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Ingår i: International Journal of Performability Engineering. - 0973-1318. ; 8:5, s. 563-572
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Tidskriftsartikel (refereegranskat)abstract
- The maintainability issue is critical for the successful and effective operation of any industry in the extreme cold climatic conditions as the working conditions are made very difficult by low temperature, ice, short period of daylight and lack of support facilities. The objective of this paper is to identify potential risk factors in cold conditions and to provide ergonomic guidelines to reduce risk factors and increase maintainability of industries deployed in cold climate
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| 23. |
- Kumar, Rajesh, et al.
(författare)
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Maintenance of machinery : negotiating service contracts in business-to-business marketing
- 2004
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Ingår i: International Journal of Service Industry Management. - : Emerald. - 0956-4233 .- 1758-6704. ; 15:3/4, s. 400-413
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Tidskriftsartikel (refereegranskat)abstract
- As industrial products are becoming more advanced and complex, the role of supporting services needed to exploit a product's function to an agreeable performance is becoming increasingly important To achieve the best performance, industrial customers are entering into service contracts with the original equipment manufacturers (OEM) or independent service providers. This, in turn essentially involves service contract negotiation between OEM/service provider and the client If such contracts are not negotiated carefully, it may lead to conflict and poor system Performance. To achieve a win-win situation for both parties, aspects such as what services to deliver, who is to deliver them, how they are to be delivered and received, and at which performance level, need to be considered in the negotiation process and agreed upon by both the provider and the client. A conceptual framework has been developed for service delivery negotiation process based on review of literature and analysis of results from a survey conducted to study the existing approaches being practiced by the industrial organizations to negotiate a service contract.
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| 24. |
- Kumar, Rajesh, et al.
(författare)
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Service delivery strategy: Trends in Mining Industries
- 2004
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Ingår i: International Journal of Surface Mining, Reclamation and Environment. - : Informa UK Limited. - 1389-5265 .- 1744-5000. ; 18:4, s. 299-307
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Tidskriftsartikel (refereegranskat)abstract
- Mine operators are increasingly outsourcing non-core business processes. Often, the maintenace issue is treated as a non-core business by the mining industry. In today's business environment, many industrial operators/users are interested in buying performance rather than physical products. It is a common practice for an original equipment manufacturer (OEM)/supplier of a product to own, operate, maintain, and support his product. Product performance in general is defined in a negotiated agreement. Even in a conventionl product scenario a user/mine operator often prefers to outsource maintenance to OEMs or contractors in order to focus on core business goals. This paper reviews the recent trends in delivery of product support within segments of the mining industry. In this paper, we advocate the adoption of 'solution-selling' and 'total care solutions' into the mining industry. There appears to be a strong likehood that these concepts can benefit the mining industry. Solution selling and total care solutions are seen as applicable to the mining industry because the product/equipment utilised in this industry are specialised and often expensive. The strategies addressed in this paper support a mine operator's option to buy process instead of physical products, and the increasing demand for a total solution.
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| 25. |
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