4,884 research outputs found

    The Product Test Scheduling Problem

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    This research focused on product test scheduling in the presence of in-process and at-completion inspection constraints. Such testing arises in the context of the manufacture of products that must perform reliably in extreme environmental conditions. Often, these products must receive a certification from prescribed regulatory agencies at the successful completion of a predetermined series of tests. Operational efficiency is enhanced by determining the optimal order and start times of tests so as to minimize the makespan while ensuring that technicians are available when needed to complete in-process and at-completion inspections. We refer to this as the product test scheduling problem. We first formulated a mixed-integer linear programming (MILP) model to identify the optimal solution to this problem and solve it using a commercial optimization package. We also present a genetic algorithm (GA) solution methodology that is implemented and solved in Microsoft Excel. Computational results are presented demonstrating the merits and consistency of the MILP and GA solution approaches across a number of scenarios

    The Developmental Test Scheduling Problem

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    Developmental testing of aircraft systems in the United States Air Force requires a complex set of resources for each test. The optimal scheduling of those resources is the job of the 412th Test Wing at Edwards Air Force Base. With more than 20 different Combined Task Forces requesting resources for roughly 300 flying missions each week, manual scheduling is a difficult task. The current process takes a team of schedulers several days to get a workable result from which they can start tailoring the final schedule. While concepts and techniques can be taken from industry scheduling problems, the body of knowledge as it relates to developmental test scheduling is sparse. The contribution of this paper is to initially document the Developmental Test Scheduling Problem, define it in structured terms for which a solution methodology can be designed, and present an Integer Programming based solution. The design allows for a scheduler to tailor an initial answer to fit nuanced and timely objectives and constraints. For this prototype effort the problem is scoped to the Iron Resources while bearing in mind the extensibility of the approach to Range Resources. This study and prototype will demonstrate results that will create an initial schedule in several hours and serve as a good starting point for the final schedule

    Optimization Models and Algorithms for Prototype Vehicle Test Scheduling

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    Automotive makers conduct a series of tests at pre-production phases of each new vehicle model development program. The main goal of those tests is to ensure that the vehicle models meet all design requirements by the time they reach the production phase. These tests target different vehicle components or functions, such as powertrain systems, electrical systems, safety aspects, etc. However, one big issue is that the cost of the resources, mainly prototype vehicles, invested in the testing process is exceedingly expensive. An individual prototype vehicle can cost over 5 times its counterpart’s price in the commercial market because many of the parts and the prototype vehicles themselves are highly customized and produced in small batches. Parts needed often require months of lead time, which constrains when vehicle builds can start. That, combined with inflexible time-window constraints for completing tests on those prototypes introduces significant time pressure, an unavoidable and challenging reality. What makes the problem even more difficult is that in addition to the prototype vehicle resources, there are other constrained supporting resources involved during the execution of those tests, such as testing facilities, instruments and equipment like cameras and sensors, human-power availability, etc. An efficient way to conquer the problem is to develop test plans with tight schedules that combine multiple tests on vehicles to fully utilize all available time while balancing the loads of other supporting resources. There are many challenges that need to be overcome in implementing this approach, including complex compatibility relationships between the tests and destructive nature of, e.g., crash tests. In this thesis, we show how to mathematically model these test scheduling problems as optimization problems. We develop corresponding solution approaches that enable quick generation of an efficient schedule to execute all tests while respecting all constraints. Our models and algorithms save test planners’ and engineers’ time, increase q their ability to quickly react to program changes, and save resources by ensuring maximal vehicle utilization.PHDIndustrial & Operations EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/137071/1/yuhuishi_1.pd

    Technology transfer: Transportation

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    The application of NASA derived technology in solving problems related to highways, railroads, and other rapid systems is described. Additional areas/are identified where space technology may be utilized to meet requirements related to waterways, law enforcement agencies, and the trucking and recreational vehicle industries

    Spartan Daily, February 15, 1955

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    Volume 42, Issue 88https://scholarworks.sjsu.edu/spartandaily/12138/thumbnail.jp
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