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Thesis (Ph. D.)--University OF MICHIGAN.

Företaget som studien utförts på upplever ett problem vid hanteringen av underhållsarbete i fabriken. Processerna för felrapportering och beställning av reservdelar är tidskrävande och involverar arbete från flera olika parter. Merparten av allt underhållsarbete som utförs är av oplanerat slag och ett fungerande uppföljningsarbete för att komma till rätta med de pro-duktionsstörningar som äger rum i processen saknas. Syftet med examensarbetet har varit att skapa underlag för att förbättra företagets effektivitet genom att optimera underhållsarbetet med hjälp av förslag till ett underhållssystem och olika tillvägagångssätt för att effektivisera underhållsarbetet. Under arbetets gång har en underhållsloggbok utformats i Excel. Loggboken används till att logga alla underhållsarbeten som inträffar i produktionen. Dessa arbeten ligger till grund för merparten av de beräkningar som utförts under projektet. Beräkningarna syftade till att kartlägga var i processen flest fel inträffar och av vilken karaktär dessa fel är. För att påvisa potentialen i ett utvecklat underhållsarbete beräknades även vilka vinstmöjligheter som kan åstadkommas genom implementering av ett underhållssystem och nya arbetsmetoder. Studien resulterade i ett förslag till ett underhållssystem som anses lämpligt utefter företagets situation och problem. Utöver införandet av ett underhållssystem stod det även klart att fö-retaget behöver minska mängden oplanerade produktionsstopp. För att lyckas med detta är det viktigt att operatörerna involveras i underhållsarbetet och utför alla arbeten av enklare slag. Underhållsavdelningen kan då, tack vare mer frigjord tid fokusera på att finna grundor-saker till problem och utföra planerade underhåll för att minska mängden oplanerade under-håll. Att effektivisera underhållsarbetet och införa Total productive maintenance (TPM) är en tidskrävande process som kan ta många år. För att underlätta för företaget och minska risken för att trilla tillbaks i gamla vanor utformades en implementeringsmodell för TPM. Modellen är ämnad som ett framtida arbete för företaget i arbetet med att utveckla effektiviteten på företaget ytterligare. / The company in the study was experiencing a problem when it comes to dealing with maintenance-work. The processes for bug tracking and ordering of spare parts is time con-suming and involves work from several different people. Most of all maintenance work performed is unplanned and a functioning follow-up work is missing. The purpose of the thesis was to help improving the company's efficiency by optimizing the maintenance work. This was achieved by a proposal for a maintenance system and vari-ous approaches to improve the maintenance work. During the project a maintenance log book was been designed in Excel. The log book is used to log all maintenance activities that occur in the production. These logs are the basis for most of the calculations carried out during the project. The calculations aimed to identify where in the process most errors occur and what the na-ture of those errors are. To demonstrate the potential of a maintenance system the profit opportunities that can be achieved through the implementation of a maintenance system and new working methods were calculated. The study resulted in a proposal for a maintenance system that suited the company's needs, situation and problems. In addition to the introduction of a maintenance system, it was also clear that the company needs to reduce the amount of unplanned downtime. To achieve this it is important to involve the operators with maintenance work and they shall perform all the works of the simpler kind. The maintenance department can then, thanks to the re-leased time, focus on finding the root causes of problems and perform scheduled mainte-nance to reduce the amount of unplanned maintenance. Improving the maintenance work and introduce Total Productive Maintenance (TPM) is a time consuming process that might go on for years. In order to facilitate the work and re-duce the risk of falling back into old habits an implementation model was designed for the TPM-work. The model is intended as a future work for the company to facilitate the work of reaching even higher efficiency.

The Texas Department of Transportation has been experiencing budget fluctuations in the recent past. These budget fluctuations can have a pronounced effect in the agency’s highway maintenance operations if key maintenance activities must be delayed due to budget constraints. The methodology proposed in this research project aims at reducing the impact of budget fluctuations on highway maintenance by identifying and ranking maintenance activities based on a set of identified maintenance objectives. With the help of maintenance experts from the highway agency, four maintenance objectives were identified and considered for this research project: include Aesthetics, Safety, System Operations and System Preservation. A similar process was conducted to identify the most relevant maintenance activities from a list of over 120 different maintenance functions used by the Texas Department of Transportation. The original list of maintenance functions was reduced by combining similar sub-categories. Ultimately, 16 maintenance functions were identified and included in this research project, representing an average of over 75 percent of the agencies maintenance expenditures between fiscal years 2008 – 2010. These four maintenance objectives and sixteen maintenance functions were then evaluated by maintenance experts from different geographic locations of the state using the Analytical Hierarchy Process to produce an Overall Relative Weight for each maintenance function. This process allowed each evaluator’s judgments and preferences to influence the final weight values and rankings of the maintenance functions. The Overall Relative Weight corresponds to each maintenance sub-category’s component from each maintenance objective and can be defined as the performance risk of not carrying out the maintenance activity. This information can be used by maintenance engineers and administrators, when faced with budget shortfalls, to suspend or reduce maintenance activities that have a lower performance risk in favor of performing activities that have a higher one. This will dampen the impact of budget fluctuations on highway maintenance operations by performing critical maintenance treatments at the expense of less critical. / text

Performance goals for a highway system are an indication of the desired system condition, and the level of service to be provided to its users. Setting the appropriate performance goals has a significant impact on the way highway agencies conduct business. With growing needs and limited resources, the consequences of setting different levels of performance goals should be examined and compared to optimize the highway infrastructure needs at the network level. Three interacting sets of costs are typically considered for a complete economic appraisal of highway projects: construction, maintenance and road use costs. Due to the shift in focus from design-and-build mode to the repair-and-maintain mode, this study focuses on maintenance related costs and the road user cost aspects only. Maintenance and rehabilitation activities on pavement infrastructure are ongoing processes that are required for the entire road network. This suggests that for long planning horizons and geographically extensive networks, their application usually results in significant financial needs. Typically, highway agencies have based their policy decisions such as the target condition levels for the system on the budget needs for maintenance and rehabilitation actions. Since in most cases, the funding needs exceed the available budget, the required preventive and routine maintenance activities suffer or are overlooked completely. Failure to timely apply these maintenance actions cause the pavements to deteriorate more rapidly into condition states that require for more expensive rehabilitation actions during the life cycle of the pavement. Over time, a vicious cycle is instigated in which the maintenance and rehabilitation needs of the network keep increasing each year. Although most highway administrators acknowledge the fact that pavement preservation is perhaps the most effective way of using the limited budgets available, the costs associated with deferring maintenance actions is oftentimes overlooked when establishing performance goals for the system. Road user costs in the form of costs for vehicle operation have been recognized as another large component of the total transportation related costs. These costs are then arguably the most important to consider for a complete economic appraisal. Ironically, they are also often disregarded while making important policy decisions. Other road user costs such as those related to the impact of traffic congestion and detours caused by construction and maintenance activities are difficult to quantify and were not accounted for in this study. Although it is widely accepted that establishing suitable performance goal is critical for system maintenance and preservation, a framework that considers the inter-relationship between conflicting objectives of minimum maintenance and rehabilitation costs, deferred maintenance costs, and vehicle operating costs to the users does not exist. This thesis proposes a methodological framework that is aimed at assisting highway agencies with the problem of objectively analyzing policy decisions in terms of the performance goals for their highway networks that would minimize the total transport costs to the society. In a case study of the proposed framework, the highway network managed by the Texas Department of Transportation was examined for different performance goals. The results from the case study indicate that setting lower performance goals lead to savings in the M&R needs, but at the same time, they also significantly increase the exogenous costs such as deferred maintenance costs and the vehicle operating costs. / text

published_or_final_version / Public Administration / Master / Master of Public Administration

published_or_final_version / Public Administration / Master / Master of Social Sciences

published_or_final_version / Industrial Engineering / Master / Master of Philosophy

The main reason for the low production efficiencies at North Coast Milling is the frequent stoppages due to equipment breakdowns and the requirement for unscheduled maintenance. In order for this factory to be able to reach the desired efficiencies, it is imperative that downtime and cost drivers in the production lines be identified and rectified. In order to achieve world-class performance, more and more companies are replacing their reactive strategies for maintenance with proactive strategies like Preventive maintenance (PM), Reliability-centred maintenance (RCM) and Condition based maintenance (CBM) and aggressive strategies like Total Productive Maintenance (TPM). While these newer maintenance strategies require increased commitments to training, resources and integration, they also promise to improve performance. New asset management philosophies are being implemented world-wide in an effort to improve industrial system reliability as well as to reduce maintenance costs. Concepts such as TPM, RCM and CBM are being customised for implementation in various industries. Real-time condition monitoring via computerised maintenance management systems has helped make it possible to transfer from a time-based maintenance strategy to a condition-based maintenance strategy. Detecting possible future failures is now a cost-effective reality that reduces considerably the risk of catastrophic failures and system breakdowns. The aIm of the study is to apply military logistic techniques to the industrial environment of North Coast Milling in order to identify downtime and cost drivers. It will be shown that more of the military logistics techniques can be incorporated into some of the existing maintenance techniques at this factory, which would aid in the achievement of maximum plant utilisation and minimum downtime.! / Thesis (MBA)- University of Natal, 2002.

Background Overweight and obesity are considerable public health issues internationally as well as in Sweden. On a global level, the obesity prevalence has nearly doubled over the last 30 years. Currently in Sweden, more than one third of all women, and slightly more than half of all men, are either overweight or obese. The long-term results of obesity treatment programs are modest as reported by other studies. The importance of extending the focus to not only obesity treatment, but also prevention of weight gain, has therefore been emphasized. Aim The overall aim of this thesis is to explore the concept of primary weight maintenance (PWM) and to increase the knowledge of the attitudes, behaviours, strategies and surrounding circumstances that are important for PWM in a Swedish middle-aged population. Material and methods All study participants were recruited based on their previous participation in a health survey in their home setting; The Västerbotten Intervention Programme (VIP) in Västerbotten Sweden (paperI-IV), or the Upstate Health and Wellness Study in Upstate New York (IV), USA. All subjects had participated twice, with a time period of ten years between health surveys. The prevalence of obesity between the years 1990-2004 was calculated for VIP participants (paper I). Ten-year non-gain (lost weight or maintained body weight within 3% of baseline weight) or weightgain (≥3%) was calculated for individuals aged 30, 40, or 50 years at baseline. A multivariate logistic regression model was built to predict weight non-gain. In-depth interviews were conducted with 23 maintainers and four slight gainers in Sweden and analysed using Grounded Theory (paper II). A questionnaire study was conducted including 2138 Swedish and 2134 US participants (paper III and IV). Analysis of variance (ANOVA), correlation, and linear regression were performed to identify attitudes, strategies, and behaviours that are predictive of PWM in different age, sex and BMI subgroups in Sweden (paper III). Further, the pattern of ten-year weightchange (% and kg) in 1999-2009 was calculated for Swedish and US women within different subgroups (paper IV). ANOVA, correlation and chi-squaretests were conducted to contrast eating and exercise habits between the two countries that may explain the differences in weight change. Results The prevalence of obesity (BMI ≥30) in Västerbotten increased from 9.4% in 1990 to 17.5% in 2004 (I). Older age, being female, being overweight at baseline, later survey year, baseline diagnosis of diabetes, and lack of snuff use increased the chances of not gaining weight. Based on the in-depth interviews, describing attitudes, behaviours and strategies of importance for PWM, a model was constructed (II). Weight maintenance was characterized as “a tightrope walk” and four strategies of significance for PWM were described as “to rely on heritage”, “to find the joy”, “to find the routine” and “to be in control”. The questionnaire study aimed at identifying predictors of PWM in different age, sex and BMI groups (III). The pattern of significant predictors was widely disparate between different subgroups. Of 166 predictors tested, 152 (91.6%) were predictive of PWM in at least one subgroup. However, only 4.6% of these were significant in half of the subgroups or more. The mean percent weight changes (in all cases weightgain), between 1999-2009 for Swedish and US women, were 4.9% (SD=5.8) and 9.1% (SD=13.7) respectively (p for t-test˂0.001) (IV). For the US women, the largest weight change occurred among the 30 year olds for all three BMI strata. For the Swedish, it was seen among overweight and obese 30 year old women. The largest difference in ten-year weight change between the two countries for any two matched subgroups was seen in normal weight 30 year olds. Significantly more of the women in this Swedish subgroup stated having more of healthy behaviours. However, there was a tendency for unhealthy behaviours to be strongly associated with greater weight gain in the US, but much less so in Sweden. Conclusion: Younger individuals, those of normal body weight, and those without health conditions (e.g. diabetes type 2) and cardiovascular riskfactors – were the least likely to maintain their weight over the 10 year period (I). Educational efforts on the prevention of overweight and obesity should therefore be broadened to include those individuals. The in-depth interview study showed great variety with regard to attitudes, strategies and behaviours important for PWM (II). The results from this study informs health personnel about the need to tailor advice related to body weight, not only to different sub-groups of individuals trying to lose weight but also to subgroups of primary weight maintainers who are trying to maintain weight. This statement was also supported by the questionnaire data, where the large disparity in the pattern of significant variables between subgroups suggests that these interventions should be tailored to the person’s demographic (age,sex and BMI) (III). Paper IV showed that even though the prevalence of obesity among Swedish women has increased substantially during these ten years, it has not kept pace with the increase in the US. One explanation for this may be that normal 30 year old Swedish women have more healthy behaviours than do US women. However, the insensitivity of the Swedish women to weight gain for healthy versus unhealthy alternatives may also be a factor. If the exact reason behind this phenomenon can be identified this may contribute to a deeper understanding of PWM both in Sweden and the US.