| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)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.
(author)
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Water
- 2022
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In: 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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Book chapter (other academic/artistic)
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| 3. |
- Kansal, Yogita, et al.
(author)
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Fixing of Faults and Vulnerabilities via Single Patch
- 2018
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In: Quality, IT and Business Operations. - Singapore : Springer. - 9789811055768 - 9789811055775 ; , s. 175-190
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Book chapter (peer-reviewed)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.
(author)
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Prioritizing Vulnerabilities using ANP and Evaluating their Optimal Discovery and Patch Release Time
- 2019
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In: International Journal of Mathematics in Operational Research (IJMOR). - : InderScience Publishers. - 1757-5850 .- 1757-5869. ; 14:2, s. 236-267
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Journal article (peer-reviewed)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.
(author)
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Inspection frequency optimization model for degrading flowlines on an offshore platform
- 2008
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In: International Journal of Reliability, Quality and Safety Engineering (IJRQSE). - 0218-5393. ; 15:2, s. 167-180
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Journal article (peer-reviewed)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.
(author)
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Estimation of parameter for rail degradation
- 2006
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In: Condition Monitoring and Diagnostic Engineering Management. - Luleå : Luleå tekniska universitet. - 9789163188060 ; , s. 605-612
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Conference paper (peer-reviewed)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.
(author)
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Product support logistics based on product design characteristics and operating environment
- 2003
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In: Proceedings of the 38th annual International Logistics Conference and Exhibition. - : Society of Logistics Engineers.
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Conference paper (peer-reviewed)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.
(author)
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Product support (spare parts procurement) strategy based on reliability characteristics and geographical location
- 2003
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In: International Conference on Industrial Logistics. - Vaasa : University of Vaasa. - 952476010X ; , s. 222-235
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Conference paper (peer-reviewed)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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