The effective use of computer based tools to support decision making in manufacturing industry is critical to business success. One of the most critical areas is during product design and especially in design for manufacture. This research will help in understanding of how manufacturing knowledge can be effectively maintained for an existing knowledge base. The work will use modern product lifecycle management tools in combination with a knowledge based environment in order to explore the effectiveness of the methods produced. This work is a part of the SAMULET (Strategic Affordable Manufacturing in the UK through Leading Environmental Technologies) research program and was done in association with an aerospace manufacturing company. The main focus of this research is to define a novel method for maintaining the machining knowledge associated with manufacturing of Xtra Wide Body (XWB) High Pressure (HP) turbine blade. The four main elements explained in this thesis are, a) the literature review done on knowledge management and knowledge maintenance, b) industrial investigation done on a manufacturing facility, c) detailed explanation of a novel manufacturing knowledge maintenance method d) four iterative case studies used for the evaluation and iterative improvement of the method. The research concludes that the aspect of knowledge maintenance is important. It is imperative to set out a formalised and mandated knowledge maintenance process in an organisation to keep the knowledge up-to-date and relevant. It has been shown that a novel task based knowledge maintenance method comprising a Knowledge Maintenance Process (KMP) and a Knowledge Maintenance Template (KMT) provides an effective route to knowledge maintenance. Three maintenance tasks, check relevancy, knowledge filtering, and integrity checking have been considered in detail for successful knowledge maintenance. Four iterative case studies have been conducted for the experimental evaluation of the maintenance method. As the result of these evaluations a novel method for maintaining the machining knowledge of XWB HP turbine blade was defined.

Approved for public release, distribution unlimited / The maintenance of large military software systems is complex, involves users as well as software professionals, and requires appropriate management, which is one of the most important factors in efficient maintenance. Maintenance management requires information about the current state of the maintenance process that should be organized within a maintenance-oriented Enginering Database. This database should include all the necessary data about software changes, system configeration, maintenance task scheduling, etc., and it should be based on a realistic model of the maintenance process. This tesis proposes a mathematical Model of Software Maintenance that uses graphs to model the relationships between maintenance tasks and software components. The Model addresses the dynamic behavior of the maintenance process and supports priority and precedence of maintenance activities. The proposed Model of Software Maintenance provides a sound basis for implementation of a maintenance-oriented engineering database that supports automation of maintenance management, e.g., process control, task scheduling, job assignments, planning and forecast, gathering and interpretation of maintenance statistics and metrics, etc.

Abstract Information integration – sharing of pertinent information between supply chain members – is vital to cope with the uncertainty and complexity embedded in service supply chains. The aim of this study is to understand the meaning, constituents, extent, and development means of information integration in service supply chain context. The research approach is abductive, emphasising the constant interplay between theory development and empirical observations. Analysis on a single case supply chain consisting of two types of maintenance service providers and a large steel manufacturer as the focal company is provided. A comprehensive conceptual framework for analysing and developing information integration in service supply chain is presented and applied in the case supply chain. Extent of integration is described through three levels of integration. Six information integration elements are used to define the levels: processes and activities, information technology use, information attributes, information sharing practices, collaborative foundation, and time-related issues. Service/market characteristics and supply chain relationship characteristics are deployed in explaining the differences in levels of integration. Depending on the level of integration, the performance effects sought and achieved through developing information integration range from operational to strategic level. Adopting a more structured approach to information integration in the case supply chain is suggested to address development areas in information sharing and improve performance. This can be implemented through a shared centralised maintenance information system, common procedures for information sharing, and commitment of supply chain actors. The framework in this study offers guidelines for choosing the appropriate level of integration in a service supply chain dyad. It shows that the special characteristics of service context can be deployed in designing and managing service supply chains. Service providers should be integrated to the supply chain just like other supply chain members, as it contributes to the supply chain performance. Differentiating the level of integration in service supply chain dyads within a supply chain based on the contextual setting is recommended. This study paves the way for better understanding and control of service supply chain links and contributes to the scarce empirical research on service supply chains.

This paper presents a quantitative comparison of perfective and corrective software maintenance performed by a large military contractor using a formal program release process. The analysis techniques used in the comparison make use of basic data collected throughout the maintenance process. The data collected allow the impact of performing perfective and corrective maintenance to be quantitatively compared. Both parametric and non-parametric statistical techniques are applied to test relationships between and among process and product data. The results provide valuable information for predicting future process and product characteristics, assessing perfective and corrective maintenance impact, and quantitatively comparing the impact of both types of requirements volatility. The results also support one common rule of thumb, cast some doubt on another, and lead to the formulation of a new one.

La dégradation géométrique de la voie ballastée sous circulation commerciale nécessite des opérations de maintenance fréquentes et onéreuses. La caractérisation du comportement des pro-cédés de maintenance comme le bourrage, la stabilisation dynamique, est nécessaire pour proposer des améliorations en terme de méthode, paramétrage pour augmenter la pérennité des travaux. La simulation numérique d'une portion de voie soumise à un bourrage ou une stabilisation dynamique permet de comprendre les phénomènes physiques mis en jeu dans le ballast. Toutefois, la complexité numérique de ce problème concernant l'étude de systèmes à très grand nombre de grains et en temps de sollicitation long, demande donc une attention particulière pour une résolution à moindre coût. L'objectif de cette thèse est de développer un outil de calcul numérique performant qui permet de réaliser des calculs dédiés à ce grand problème granulaire moins consommateur en temps. La méthodologie utilisée ici se base sur l'approche Non Smooth Contact Dynamic s(NSCD) avec une discrétisation par Éléments Discrets (DEM). Dans ce cadre, une méthode de dé-composition de domaine (DDM) alliée à une parallélisation adaptée en environnement à mémoire partagée utilisant OpenMP sont appliquées pour améliorer l'efficacité de la simulation numérique. / The track deterioration rate is strongly influenced by the ballast behaviour under commercial traffic. In order to restore the initial track geometry, different maintenance processes are performed, like tamping, dynamic stabilisation. A better understanding of the ballast behaviour under these operations on a portion of railway track is a key to optimize the process, to limit degradationand to propose some concept for a better homogeneous compaction. The numerical simulation isdeveloped here to investigate the mechanical behaviour of ballast. However, the main difficultiesof this research action concerns the size of the granular system simulation increasing both in termof number of grains and of process duration. The purpose of this thesis is to develop an efficient numerical tool allows to realize faster computations devoted to large-scale granular samples. In this framework, the Non-Smooth Contact Dynamics (NSCD) of three-dimensional Discrete ElementMethod (DEM) simulations, improved by Domain Decomposition Method (DDM) and processedwith the Shared Memory parallel technique (using OpenMP) has been applied to study the ballast media mechanics.

Winter road maintenance is a necessity during the winter in Sweden, since the weather reduce traffic safety and accessibility, which have great impact on people and society in general. Unlike the degradation process of paved road surface and subgrade, that develops slowly over several years, the general state of the winter road can change significantly within a couple of hours, thus demanding more of road maintenance organisations when it comes to planning and initiating maintenance actions. Today there is a wide range of available sensor technology, that can be utilized to monitor the condition of the winter road and provide decision makers with the required information to initiate maintenance activities at the right time. However, it is necessary for the user, e.g. maintenance staff and decision makers, to know how this type of technology can be applied to make the winter road maintenance more efficient. The aim of this thesis is to define the winter road maintenance process, what obstacles and problems are present and the information requirements that are associated with planning, initiating and performing the winter road maintenance activities. The thesis focuses on the maintenance process for municipalities in northern Sweden using the city of Kiruna as a case study. An interview study was performed at Tekniska Verken in Kiruna to collect empirical data, which forms the basis for the process- and flow charts that are presented in the result. Common failure modes, connected to the failures that usually leads to the initiation of a maintenance activity, are identified, based on the interviews and the quality declaration for winter road maintenance. The failure modes were connected to the workflows, to show the phases of the workflow where the information is useful. Based on this, suitable sensor technology is proposed, which partly or fully meet the identified information requirements, and monitors the interesting failure modes of each maintenance activity. The results show that the greatest need for information is found in the stage of assessment and decision-making regarding initiation of maintenance actions, especially when it comes to initiation of snow plowing and de-icing activities. Using vehicle-based sensor technology, the condition of the road can be continuously monitored, and the initiation of maintenance activities can be triggered when reaching a threshold. Having road weather information stations, e.g. monitoring air and road temperature, wind speed, precipitation and road condition, is also an important source of information for municipal winter road maintenance. The use of sensor technology results in maintenance processes with fewer activities and decision steps, and it generates more reliable data that simplifies the decision-making. / Vinterväghållning är en nödvändighet under vinterhalvåret i Sverige, då väderlek har en stor påverkan på trafiksäkerhet och framkomlighet för trafikanter. Till skillnad från nedbrytningen av belagd väg under barmarkssäsongen, som sker stegvis under flera år, kan vintervägens tillstånd försämras avsevärt inom bara ett par timmar. Detta ställer högre krav på vägunderhållsorganisationer vad gäller planering och initiering av underhållsåtgärder. Idag finns ett brett utbud av sensorteknik som kan användas för att övervaka vintervägens tillstånd, och förse beslutsfattare med nödvändig information för att kunna initiera underhållsaktiviteter vid rätt tidpunkt. Det är dock nödvändigt att användaren, dvs. underhållspersonal och beslutsfattare, har kunskap om hur denna teknik kan användas för att effektivisera vinterväghållningen. Syftet med arbetet är att ta reda på hur underhållsprocessen för kommunal vinterväghållning är utformad, vilka hinder och problem som förekommer samt vilket informationsbehov som finns i samband med planering, initiering och utförande av vinterväghållningsaktiviteter. Arbetet är avgränsat till att analysera vinterväghållningen i Kiruna kommun. En intervjustudie utfördes vid Tekniska Verken i Kiruna för insamling av empiriskt material, vilket utgjorde underlaget för de process- och flödeskartor som presenteras i resultatet. Med utgångspunkt ur intervjumaterialet och kommunens kvalitetsdeklaration för vinterväghållning, identifierades vanliga felmoder kopplade till de funktionsfel som leder till initiering av underhållsaktivitet. Felmoderna kopplades sedan till arbetsflödena, genom att visa i vilket skede i arbetet som information om dessa är användbar. Utifrån detta gavs förslag på lämplig sensorteknik som helt eller delvis kan tillgodose informationsbehovet som identifierats, samt övervaka de felmoder som är intressanta för respektive underhållsaktivitet. Resultatet av undersökningen visar att det är vid bedömning och beslut om initiering av underhållsåtgärd som informationsbehovet är störst, framför allt när det handlar om initiering av snöröjning och halkbekämpning. Genom att använda sensorteknik för kontinuerlig övervakning av vägens tillstånd, kan underhållsaktiviteter initieras vid definierade gränsvärden. Egna vägväderstationer som övervakar och mäter exempelvis luft- och vägtemperatur, vindstyrka, nederbördsmängd och typ samt väglag, kan vara till nytta för den kommunala vinterväghållningen oavsett vilken underhållsaktivitet det handlar om. Användningen av denna typ av teknik leder till effektiviserade underhållsprocesser med färre aktiviteter och beslutssteg, samt förenklad beslutsfattning baserat på mer tillförlitliga mätdata.