Browsing by Subject "Maintenance"
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Item An in-depth study of personal creative maintenance(2009-05-15) Carroll, Suzanne CatriceThis qualitative research study was created to examine four individual creative producers in the field of the visual and performing arts from different walks of life to determine if any similarities between the producers emerged. More specifically, the researcher was interested in (a) investigating how creative thinkers became creative producers and (b) investigating how these creative producers maintained and sustained high levels of creative production. After thoroughly utilizing the constant comparative method of data collection and analyzation, which includes peer debriefs, member checks, and other various qualitative techniques to keep the study internally valid, three themes emerged from the grounded data. Theme one is that a continuous evolution of the artist exists. This is brought about by parental support and critical incidents. Furthermore, these participants hold an enduring feeling of passion and responsibility for their field of creative endeavor. Theme two is that each creative producer spoke of having an intense inner sense of self. This sense of self first emerged within these participants at an early age, and its adult presence is evident in how these producers (a) cannot separate the artist from the person, (b) are aware of their personal and artistic growth, (c) are aware of their personal metacognitive strategies of generating ideas, and they sometimes use their art as a source of personal therapy. Theme three talks about how these creative producers see art as a greater whole. Its evidence is manifested within these participants perception that art has a very humanistic purpose by its effect on their communities.Item Extension of activity analysis methodology to maintenance, shutdown, and turnarounds in petrochemical facilities(2016-08) Shounak, Goodidar Hemmanoor Arjun; Caldas, Carlos H.; Borcherding, John DStudies show that construction productivity has been stagnant for decades. Interestingly, other industries like manufacturing, automobile and agriculture have witnessed a steep increase in productivity, nearly twice, over the same period of time. It has been the norm for many continuous improvement methods, employed by these industries, to claim credit for this trend. While inadequacies in a range of parameters like management practices, organizational behavior, contractual differences, and other planning functions affect poor productivity, the first step towards any improvement program is to measure the existing condition. The importance of measuring and improving productivity has become increasingly critical and significant with raging project capital costs and complexity, especially in the petroleum industry. This research focusses on providing a productivity language for petrochemical owners and contractors. The developed methodology helps them to communicate improvement strategies with each other and within their organization beyond construction leading into maintenance and shutdown turnarounds. Activity Analysis is a productivity assessment and improvement method developed by the Construction Industry Institute (CII) in 2010. This thesis describes the adaptation of activity analysis methodology that was developed to measure productivity indicators at petrochemical facilities on construction, maintenance and shutdown turnaround activities between 2015 and 2016. It also provides an overview on the activity analysis software developed for data collection, which is a byproduct of this research. This study also provides a summary of expected trends and challenges in petrochemical industries, and strategies that could be implemented to enhance the direct work rate in both construction and maintenance environment.Item Facilitating transfer and maintenance in school-aged children who stutter : a guidebook for clinicians(2014-05) Wong, Allison Mei-Li; Byrd, Courtney T.This report was developed to: a) enhance the clinician’s understanding of transfer and maintenance as it relates to stuttering, b) explore the unique challenges that face the school-aged population, c) examine research outside of the field that may be of benefit for school-aged stuttering clients, and d) provide the clinician with examples and activities that will facilitate the transfer and maintenance of stuttering treatment. The report will include a brief discussion of transfer and maintenance. The remainder of the report will focus on facilitating transfer and maintenance by increasing motivation, self-efficacy, realistic goal setting, and self-regulation.Item Impact of budget uncertainty on network-level pavement condition : a robust optimization approach(2013-12) Al-Amin, Md; Zhang, Zhanmin, 1962-Highway agencies usually face budget uncertainty for pavement maintenance and rehabilitation activities due to limitation in resources and changes in government policies. Highway agencies perform maintenance planning for the pavement network commonly based on the nominal available budget without taking the variability of budget into consideration. The maintenance program based on deterministic budget consideration results in suboptimal maintenance decisions that impact the overall network conditions, if the budget falls short in some future year in the planning horizon. As a result, it is important for highway agencies to adopt maintenance and rehabilitation policies that are protected against the uncertainty in maintenance and rehabilitation budget. In this study a multi-period linear integer programming model is proposed with its robust counterpart considering uncertain maintenance and rehabilitation budget. The proposed model is able to provide a maintenance and rehabilitation program for the pavement network that results in minimal impact of budget variability on the network conditions. A case study was carried out for a network of ten pavement sections. The solution of the robust optimization model was compared to those with deterministic model. The results show that the robust optimization model is an attractive method that can minimize the effect of budget uncertainty on pavement conditions at the network level.Item Optimization models for transport and service scheduling(2011-05) Derinkuyu, Kursad; Balakrishnan, Anant; Kutanoglu, Erhan; Bard, Jonathan F.; Morton, David P.; Waller, Travis S.This dissertation focuses on service scheduling and transshipment problems. The study of service scheduling is motivated by decisions facing service planners, who must inspect and maintain geographically dispersed infrastructure facilities. We study the problem of deciding which operations a service unit must perform at each customer location, given the sequence in which the unit periodically visits these locations. Each customer requires multiple service operations, and each operation has a time-varying completion or penalty cost that depends on the previous service time. The goal is to schedule the service start time for each customer and select the operations to perform so as to minimize the total completion cost. We first discuss how to solve a special case of this problem in which each site is visited only once per service cycle. We formulate this problem as a discrete time indexed network flow problem and prove that it is NP-hard in the ordinary sense. Then, we represent the problem as a multidimensional shortest path problem with path-dependent arc lengths. In this structure, arc costs depend on the total time spent for all customers. The resulting formulation is solvable via algorithms that have pseudo-polynomial run times. Computational results show that the shortest path approach outperformed the general network flow model. We then analyze the general case of this problem, in which each site can be visited more than once and prove that the problem is NP-Hard in the strong sense. We discuss the valid cuts and describe the preprocessor that reduces the problem size. Next, we examine an application to the general case of the problem and develop a fast and effective heuristic procedure that repeatedly applies the shortest path approach to subsequences that do not visit any customer more than once. Computational results for several problem instances show that the proposed heuristic identifies near optimal results very quickly, whereas a general purpose integer-programming solver (CPLEX) is not able to find an optimal solution even after many hours of computational time. Then we focus on techniques such as problem reduction, branching variables, and subdividing problem to smaller problems to get better solution times for the actual problem. Computational results show that these techniques can improve solution times substantially. Finally, we study a transshipment problem, in which the shipments need to be transported from their origin to destination and are subject to the logical and physical transportation network on which they rely. We consider a space-time network that allows one to formulate the problem as a multi-commodity network flow problem with additional side constraints and show the complexity results. We propose alternative models and propose algorithms for lower and upper bound calculations.Item Semiconductor manufacturing inspired integrated scheduling problems : production planning, advanced process control, and predictive maintenance(2008-08) Cai, Yiwei; Kutanoglu, Erhan; Qin, SizhaoThis dissertation is composed of three major parts, each studying a problem related to semiconductor manufacturing. The first part of the dissertation proposes a high-level scheduling model that serves as an intermediate stage between planning and detailed scheduling in the usual planning hierarchy. The high-level scheduling model explicitly controls the WIP over time in the system and provides a more specific guide to detailed scheduling. WIP control is used to balance the WIP (Work In Process) level and to keep the bottleneck station busy to maintain a high throughput rate. A mini-fab simulation model is used to evaluate the benefits of different approaches to implementing such a high-level scheduling model, and to compare different WIP control policies. Extensive numerical studies show that the proposed approaches can achieve much shorter cycle times than the traditional planning-scheduling approach, with only a small increase in inventory and backorder costs. With increasing worldwide competition, high technology product manufacturing companies have to pay great attention to lower their production costs and guarantee high quality at the same time. Advanced process control (APC) is widely used in semiconductor manufacturing to adjust machine parameters so as to achieve satisfactory product quality. The interaction between scheduling and APC motivates the second part of this dissertation. First, a single-machine makespan problem with APC constraints is proved to be NPcomplete. For some special cases, an optimal solution is obtained analytically. In more general cases, the structure of optimal solutions is explored. An efficient heuristic algorithm based on these structural results is proposed and compared to an integer programming approach. Another important issue in manufacturing system is maintenance, which affects cycle time and yield management. Although there is extensive literature regarding maintenance policies, the analysis in most papers is restricted to conventional preventive maintenance (PM) policies, i.e., calendar-based or jobbased PM policies. With the rapid development of new technology, predictive maintenance has become more feasible, and has attracted more and more attention from semiconductor manufacturing companies in recent years. Thus, the third problem considered in this dissertation is predictive maintenance in an M/G/1 queueing environment. One-recipe and two-recipe problems are studied through semi-Markov decision processes (SMDP), and structural properties are obtained. Discounted SMDP problems are solved by linear programming and expected machine availabilities are calculated to evaluate different PM policies. The optimal policy can maintain a high machine availability with low long-run cost. The structures of the optimal PM policies show that it is necessary to consider multiple recipes explicitly in predictive maintenance models.Item The web-based graphic service request system for facility management of apartments(Texas A&M University, 2006-10-30) Lee, Kwang JunThis research investigates the feasibility of web technology as a means of handling service requests for delivering high quality service in building operation and maintenance. This research proposes a web-based graphic service request (WGSR) system as a pragmatic solution to the limitations of current computerized maintenance management system (CMMS) processes. Service request process in CMMS was developed as text-based, so that it is hard for ordinary tenants to use. Therefore, when tenants have a problem in a facility, they prefer calling in service requests or going to the office instead of using the internet service request application. In practice, work orders and records are often misplaced - resulting in lower efficiency and customer satisfaction. This may be overcome by a system that states information digitally and provides a web-based Graphic Service Request (WGSR) interface. The interface allow customers to report environmental problems in the facility, trace their work order progress, view schedules for maintenance, and provide feedback for service online. The WGSR system is an end-user point-and-click graphical interface that allows residents to request service by selecting a problem fixture on a floor plan image. By using HTML image map tags and combination of location, part, and types of problem identification number, the resident's input produces a text-based problem report for Facility Management (FM) departments that allows them to service requests on the fly. To solve the complexity and inefficiency issues of CMMS, the user interface for the WGRS system consists of a perspective drawing or isometric drawing of each unit's plan. An empirical test of the system and post-task survey was conducted to determine the efficiency and usefulness of the system. The analysis of the results shows the system to be efficient and convenient in several fields, including comprehensibility, navigability, simplicity, clarity, compatibility, and graphic appeal. This result shows that residents prefer to use the WGSR system and could reduce the effort needed to make and receive service request phone calls and input information into a database. The labor and time for daily work could be saved to recognize problems correctly and set the right schedule so that this could be used for preventive work and project work.