Papers by Peter A. Sandborn
WSPC series in advanced integration and packaging, Dec 13, 2016
Journal of physics, 2020
Yaw error lowers the efficiency and reliability of wind turbines resulting in higher maintenance ... more Yaw error lowers the efficiency and reliability of wind turbines resulting in higher maintenance costs. LIDAR devices can correct the yaw error; however, they are expensive, which creates a trade-off between their costs and benefits. In this study, a stochastic discrete-event simulation model is developed that models the operation of a wind farm. We optimize the net present value (NPV) changes associated with using LIDAR devices in a wind farm to determine the optimum number of LIDAR devices and their associated turbine stay time as a function of number of turbines in the wind farm for specific turbine sizes.
WSPC series in advanced integration and packaging, Dec 13, 2016
WSPC series in advanced integration and packaging, Dec 13, 2016
In the care of patients, medical analyzes are essential evidences to confirm a diagnosis. In Sene... more In the care of patients, medical analyzes are essential evidences to confirm a diagnosis. In Senegal, in 2005 and according to the National Health Accounts, Medical Biologys pending were estimated at 4.5 billion franc CFA. .Unlike drugs, very few studies have been conducted to assess the cost of medical biology acts in the care of patients. It is for this reason that we decided to determine the cost of these acts performed in the laboratory of Biochemistry, Aristide Le Dantec Hospital (National Referral hospital).This study was conducted over a period of three (3) months. This is a retrospective crosssectional study in analytical target on the calculation of the cost of Biochemistry examinations. All parameters analyzed during this period have been included but have excluded all the parameters that were not measured due to breakage of reagents.The method used is the ABC method based on the identification of all activities for the determination of product costs.This study has shown that wages represent a very significant proportion of the total costs(60%). We have found that the cost is much lower if the analyzes are done with a plc.Our study has shown that using a plc is having an impact on reducing costs. This confirms that the interest for the state is to provide efficient equipment in order to reduce the cost of services.
This project has developed a stochastic modeling capability for detailed life-cycle cost analysis... more This project has developed a stochastic modeling capability for detailed life-cycle cost analysis and associated return on investment (ROI) analysis that can be used to assess offshore wind farm O&M management alternatives and technology insertion. • Technology providers need business cases that demonstrate the economic value of their technology • These are "cost avoidance" (not cost savings) business cases, which are not simple and requires the calculation of accurate ROIs • While many life-cycle cost models have been developed, existing models generally do not have the capability to calculate the stochastic ROIs needed to produce business cases • Existing life-cycle cost models also do not include critical legacy system effects.-Aging supply chain (obsolete parts, counterfeit parts, degrading in storage etc.)-Wear out of key subsystems-Loss of critical human skills, etc. Accurate life-cycle costing is a key enabler for wind farm operation and maintenance (O&M) optimization. Research has shown that maintenance is not optimized and that significant opportunities exist for reducing the total cost for maintenance and production losses, especially for large wind farms. This paper describes a stochastic life-cycle cost model and an associated return on investment (ROI) model that can be used to assess wind farm O&M management alternatives and technologies. While formulating the ROI associated with investing money in a financial instrument is simple, the calculation of an ROI associated with a future cost avoidance that results from the implementation of a particular technology or process, or from a particular system management approach is not simple. In this paper we develop a simulation-based analysis for determining the ROIs for activities relevant to wind farm O&M. While there are analyses that forecast the ROI of wind turbines and the energy ROI (EROI), these high-level analyses are not applicable to the cost avoidance ROI calculations associated with technology or methodology adoption.
Volume 4: 18th Design for Manufacturing and the Life Cycle Conference; 2013 ASME/IEEE International Conference on Mechatronic and Embedded Systems and Applications, Aug 4, 2013
Long life cycle products, commonly found in aviation, medical and critical infrastructure applica... more Long life cycle products, commonly found in aviation, medical and critical infrastructure applications, are often fielded and supported for long periods of time (20 years or more). The manufacture and support of long life cycle products rely on the availability of suitable parts, which over long periods of time, leaves the parts susceptible to supply chain disruptions such as suppliers exiting the market, allocation issues, counterfeit part risks, and part obsolescence.Proactive mitigation strategies exist that can reduce the impact of supply chain disruptions. One solution to mitigating the supply chain risk is the strategic formulation of part sourcing strategies (optimally selecting one or more suppliers from which to purchase parts over the life of the part’s use within a product or organization). Strategic sourcing offers a way of avoiding the risk of part unavailability (and its associated penalties), but at the expense of qualification and support costs for multiple suppliers. An alternative disruption mitigation strategy is hoarding. Hoarding involves stocking enough parts in inventory to satisfy the forecasted part demand (for both manufacturing and maintenance requirements) of a fixed future time period. This excess inventory provides a buffer that reduces the effect of supply chain disruptions on the part total cost of ownership (TCO), but increases the total holding cost.This paper presents a method of performing tradeoff analyses and identifying the optimal combination of second sourcing and hoarding for a specific part and product scenario. A case study was performed to examine the effects of hoarding on both single and second sourced parts. The case study results show that hoarding can contribute to a decrease in the cumulative TCO and a decrease in its variance.Copyright © 2013 by ASME
This paper describes the creation of a taxonomy and evaluation criteria for organizing and assess... more This paper describes the creation of a taxonomy and evaluation criteria for organizing and assessing DMSMS tools, databases, and services. These activities are useful in the short term to assess the state of the present DMSMS management tools and the gaps that may be present within them; and necessary in the longer term to lay the ground work for constructing an ontology that will be necessary to achieve webcentric, enterprise-wide DMSMS management solutions.
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Jun 7, 2016
Railway assets suffer wear and tear during operation. Prognostics can be used to assess the curre... more Railway assets suffer wear and tear during operation. Prognostics can be used to assess the current health of a system and predict its remaining life, based on features that capture the gradual degradation of its operational capabilities. Prognostics are critical to improve safety, plan successful work, schedule maintenance, and reduce maintenance costs and down time. Prognosis is a relatively new area; however, it has become an important part of condition-based maintenance of systems. As there are many prognostic techniques, usage must be tuned to particular applications. Broadly stated, prognostic methods are either data driven, or rule or model based. Each approach has advantages and disadvantages, depending on the hierarchical level of the analysed item; consequently, they are often combined in hybrid applications. A hybrid model can combine some or all model types; thus, more-complete information can be gathered, leading to more-accurate recognition of the impending fault state. However, the amount of information collected from disparate data sources is increasing exponentially and has different natures and granularity; therefore, there is a real need for context engines to establish meaningful data links for further exploration. This approach is especially relevant in railway systems where the maintainer and operator know some of the failure mechanisms, but the sheer complexity of the infrastructure and rolling stock precludes the development of a complete model-based approach. Hybrid models are extremely useful for accurately estimating the remaining useful life (RUL) of railway systems. This paper addresses the process of data aggregation into a contextual awareness hybrid model to obtain RUL values within logical confidence intervals so that the life cycle of railway assets can be managed and optimized.
Volume 3: 6th Design for Manufacturing Conference
Yielded cost is defined as cost divided by yield and can be used as a metric for representing an ... more Yielded cost is defined as cost divided by yield and can be used as a metric for representing an effective cost per good (non-defective) assembly for a manufacturing process. Although yielded cost is not a new concept, it has no consistent definition in engineering literature, and several different formulations and interpretations exist in the context of manufacturing and assembly. In manufacturing, yield is the probability that an assembly is non-defective. To find the effective cost per good assembly that is invested in the manufacturing or assembly process, cost is accumulated and divided by yield. This paper reviews and correlates existing yielded cost formulations and presents a new method that enables consistent measurement of sequential process flows. This new method views the yielded cost associated with an individual process step (step yielded cost) as the change in the process’s yielded cost when the step is removed from the process. This approach is preferred because it i...
Prognostics and Remaining Useful Life (RUL) Estimation, 2021
Prognostics and Remaining Useful Life (RUL) Estimation, 2021
Computational Electronics, 1991
One of the most time consuming activities in new product development is associated with reliabili... more One of the most time consuming activities in new product development is associated with reliability assessment and qualification. This is defined as a process to verify whether the anticipated reliability is indeed achieved under actual life cycle loads for some specified length of time. Reliability assessment and qualification is usually accomplished by testing under accelerated loads to achieve time compression. Typical qualification methods have been borrowed from the military, without knowledge of the rationale or assessment of the true benefits. In fact, prediction of field reliability from these tests has generally been quite poor. Nevertheless, the amount and length of qualification testing has increased over the years. This paper aims to provide a background to the qualification problem that much of industry is faced with today. Then provide an approach to reliability assessment, which provides a method for qualification requiring very little time and money, because the process is simulated.
Fast moving technologies have caused high-tech components to have shortened life cycles, renderin... more Fast moving technologies have caused high-tech components to have shortened life cycles, rendering them obsolete quickly. Technology obsolescence creates significant problems for product sectors that use components that are only available for a short period of time for manufacture and maintenance of long field-life systems. Technology obsolescence can make design changes of systems prohibitively expensive, and results in high life cycle costs of systems. While the impact and pervasiveness of obsolescence problems are growing, existing tools and solutions are lacking the needed information and knowledge to do much more than focus on reactively managing obsolescence. Current methods and tools are limited by data conflicts and data inexplicitness, incompleteness, and inconsistency. In response to the drawbacks of current tools, comprehensive knowledge representation that allows information sharing, reuse, and collaboration on obsolescence issues across different organizations is requir...
Renewable Energy, 2021
Abstract Throughout the world, various policies and regulations exist that govern the buying and ... more Abstract Throughout the world, various policies and regulations exist that govern the buying and selling of energy. In the United States, government mandates have been developed in the form of State-specific Renewable Portfolio Standards (RPSs) that require specific percentages of renewable energy consumption. RPS laws are managed through Power Purchase Agreements (PPAs) and bundled Renewable Energy Credits (RECs), other parts of the world use similar instruments. Both PPAs and RECs typically use a Levelized Cost of Energy (LCOE) calculation to determine the price of energy and may contain limitations on how much energy can be purchased. Conventional LCOE calculations do not account for asymmetry in cash flows that arise from PPA and REC imposed penalties, which can lead to significant errors. The objective of this paper is to use a modified LCOE to demonstrate the impacts of energy purchase limits and the combined effect of multiple energy generators entering into an energy purchase agreement with one buyer. The Maryland Offshore Renewable Energy Credit (OREC) is used as an analysis vehicle, which demonstrates that the effective LCOE can decrease by as much as 36% or increase by as much as 15% when RPS and REC energy purchase limits introduce cash flow asymmetry.
Engineering Management Journal, 2016
Assumptions used in field reliability data analysis may be seldom made explicit or questioned in ... more Assumptions used in field reliability data analysis may be seldom made explicit or questioned in practice, yet these assumptions affect how engineering managers develop metrics for use in longterm support contracts. To address this issue, this article describes a procedure to avoid the pitfalls in employing the results of field data analysis for repairable items. The procedure is then implemented with the aid of a simplified example based on a real case study in defense avionics, and is streamlined so that the computations can be replicated in other applications.
Volume 3: 28th Computers and Information in Engineering Conference, Parts A and B, 2008
Prognostics and Health Management (PHM) provides an opportunity for lowering sustainment costs, i... more Prognostics and Health Management (PHM) provides an opportunity for lowering sustainment costs, improving maintenance decision-making and providing product usage feedback into the product design and validation process. The adoption of PHM approaches requires consideration and planning for integration into new and existing systems, operations, and processes. However, PHM must provide a significant advantage in order to add value for the maintenance process and commitments to implement and support PHM approaches cannot be made without the development of supporting business cases. The realization of PHM requires implementation at different levels of scale and complexity. The maturity, robustness, and applicability of the underlying predictive algorithms impact the overall efficacy of PHM within an enterprise. The utility of PHM to inform decision-makers within tight scheduling constraints and under different operational profiles likewise affects the cost avoidance that can be realized....
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Papers by Peter A. Sandborn