Dissertations / Theses on the topic 'Reliability of logistics'

When customers buy a new product, the reliability related issues such as the warranty/post-warranty service and the performance of the product are becoming important factors in the customers' decision-making process. In this dissertation, some important aspects in estimating both warranty and post-warranty repair demands have been studied. To ensure the new product will have a good performance, the availability of a repairable k-out-of-n:G system considering spare parts logistics is investigated. The installed base of the product varies with time due to both new sales and units being taken out of service is considered. We explicitly address the fact that customers may not always request repairs for failed units and formulate the corresponding warranty and post-warranty repair demands for a general failure process. For the case where the product failure time is exponential, we derive the closed-form expressions for the two types of repair demands for both an individual unit and the installed base. A step further, we develop an integrated model to estimate the gross profit for a new durable product to be sold in a fixed sales period at a fixed price. The sales over time is characterized by a stochastic Bass model and the production system is a make-to-order type of system. An approximate, yet accurate approach is developed to quantify the expected total cost of production involving a learning effect. The analysis of key parameters that affect the optimal gross profit is carried out in numerical examples. Finally, the availability management of a new product (or system) is studied. We introduce a collection of operational availability maximization problems, in which the component redundancy levels and the spares stock quantities are to be determined simultaneously under economic and physical constraints.

This thesis focuses on the developing of statistical methodology in reliability and quality engineering, and to assist the decision-makings at enterprise level, process level, and product level. In Chapter II, we propose a multi-level statistical modeling strategy to characterize data from spatial logistics systems. The model can support business decisions at different levels. The information available from higher hierarchies is incorporated into the multi-level model as constraint functions for lower hierarchies. The key contributions include proposing the top-down multi-level spatial models which improve the estimation accuracy at lower levels; applying the spatial smoothing techniques to solve facility location problems in logistics. In Chapter III, we propose methods for modeling system service reliability in a supply chain, which may be disrupted by uncertain contingent events. This chapter applies an approximation technique for developing first-cut reliability analysis models. The approximation relies on multi-level spatial models to characterize patterns of store locations and demands. The key contributions in this chapter are to bring statistical spatial modeling techniques to approximate store location and demand data, and to build system reliability models entertaining various scenarios of DC location designs and DC capacity constraints. Chapter IV investigates the power law process, which has proved to be a useful tool in characterizing the failure process of repairable systems. This chapter presents a procedure for detecting and estimating a mixture of conforming and nonconforming systems. The key contributions in this chapter are to investigate the property of parameter estimation in mixture repair processes, and to propose an effective way to screen out nonconforming products. The key contributions in Chapter V are to propose a new method to analyze heavily censored accelerated life testing data, and to study the asymptotic properties. This approach flexibly and rigorously incorporates distribution assumptions and regression structures into estimating equations in a nonparametric estimation framework. Derivations of asymptotic properties of the proposed method provide an opportunity to compare its estimation quality to commonly used parametric MLE methods in the situation of mis-specified regression models.

Thesis (Ph. D.)--Industrial & Systems Engineering, Georgia Institute of Technology, 2004.<br>Erera, Alan, Committee Member ; Liang, Peng, Committee Member ; Hayter, Anthony, Committee Member ; Lu, Jye-Chyi, Committee Co-Chair ; Kvam, Paul, Committee Co-Chair. Vita. Includes bibliographical references (leaves 79-83).

Thesis (M.S. in Management)--Naval Postgraduate School, 2002.<br>Title from title screen (viewed Nov. 8, 2005). "December 2002." Includes bibliographical references (p. 144-152). Also issued in paper format.

Approved for public release; distribution is unlimited.<br>Approved for public release; distribution is unlimited.<br>Combat system reliability is central to creating combat power, determining logistics supportability requirements, and determining systems' total ownership costs, yet the Marine Corps typically monitors only operational availability. While acceptable operational availability may be achieved through intensive maintenance and the stocking of needed repair parts in large quantities, this increases the logistics burden on the combat commander and is costly in terms of personnel, time, and funding. Data required to compare system reliability requirements in source documents, such as the Operational Requirements Document and the acquisition contract, to achieved reliability of fielded systems is generally not collected, maintained, or available. Contractual obligations to attain system reliability, if any, could not be enforced, and any increase in sustainability costs associated with unmet reliability thresholds is borne by the Marine Corps, draining scarce funding from other priorities. This research interprets data and perspectives, as collected from a reliability management survey administered to acquisition workforce professional s, and collectively summarizes common inhibitors of effective reliability management, why they occur, lessons learned, and potential methods for mitigating the inherent risks. The results ascertain a variety of technical, programmatic, managerial, incentive, and procedural issues that the Marine Corps encounters concerning system reliability requirements and achievement.

In the last decades, the global markets have driven the manufacturing and service companies to be more flexible and efficient as for goods and services operations are concerned. More attention has also been paid to the performance of productive and logistic systems. In fact, the strict relation between flexibility and competitiveness of companies and efficiency of their productive plants and logistics is well known. It is important to define, monitor and improve the efficiency of industrial and logistic systems. Many definitions of efficiency have been introduced and the most important is the Overall Equipment Efficiency (OEE), introduced by Nakajima at the end of the ‘80s. This index quickly spread in many industrial fields and it connects the efficiency of productive and logistic systems to three main factors: the availability of systems, the quality of produced goods/services and the productive and logistics performance. Between these factors, more attention has been paid to the parameter related to the availability of systems. Moreover, it is known that the availability is strictly linked to the survival behavior of systems. In this field, the manuscript introduces several innovative theoretical models for the survival analysis of components and productive-logistics complex systems, with particular attention to the systems which operate in different operative conditions. This thesis is structured in the following main parts: 1. Introduction of most important models of OEE and their relationship with availability of productive and logistic systems; 2. Discussion about the relation between survival behavior and operative conditions; 3. Definition and development of innovative theoretical models for the system reliability modeling and their validation thanks to several industrial applications; 4. Definition and development of innovative maintenance policies for the efficiency improvement, based on the extension of scientific literature, thanks to the theoretical models introduced in previous parts; 5. Definition of innovative model for the performance analysis of logistic systems, in particular for Automated Storage/Retrieval Systems and comparison with the existing models. The research has also been carried out in collaboration with Prof. Hoang Pham, director of Department of Industrial and Systems Engineering, Rutgers University, Piscataway – New Jersey (USA), during a period the author spent as “visiting researcher” in the Quality and Reliability Engineering Laboratory of that department. The present work has carried out to the publishing of several scientific contributions in relevant International Journals and Conferences, like International Journal of Mathematics in Operational Research, International Journal of System Science and IEEE Transactions on Man, Cybernetics and Systems.<br>Negli ultimi decenni, il mercato ha portato le aziende manifatturiere e di servizi ad essere più flessibili e efficienti nella produzione dei propri beni e servizi. Maggior attenzione è stata quindi posta nei confronti delle performance dei sistemi produttivi-logistici. É infatti noto lo stretto legame tra flessibilità e competitività delle aziende con l’efficienza degli impianti produttivi e della logistica caratterizzanti le stesse. É importante quindi riuscire a definire, monitorare e migliorare l’efficienza degli impianti industriali e dei sistemi logistici. Sono stati introdotte numerose definizioni di efficienza, tra le quali la più importante è l’Overall Equipment Efficiency (OEE), introdotta alla fine degli anni ’80 da Nakajima. Tale indice si è presto diffuso in numerosi settori e lega l’efficienza dei sistemi produttivi e logistici a tre fattori principali: la disponibilità dei sistemi, la qualità dei beni/servizi e le performance produttive e logistiche. Tra questi fattori, maggior attenzione è stata posta al parametro relativo alla disponibilità dei sistemi. Inoltre è noto come la disponibilità dei sistemi sia strettamente legata al comportamento affidabilistico dei sistemi stessi. Su tale fronte, questo elaborato introduce innovativi modelli teorici per l’analisi dell’affidabilità e disponibilità di componente e sistemi logistico-produttivi, con particolare attenzione ai sistemi soggetti a diverse condizioni operative. La tesi si articola in tali principali parti: 1. Introduzione ai principali modelli di OEE e loro legame con la disponibilità dei sistemi logistico-produttivi; 2. Discussione del legame stretto tra comportamento affidabilistico e condizioni ambientali; 3. Sviluppo di modelli teorici innovativi per la modellazione delle caratteristiche affidabilistiche e loro validazione tramite applicazioni industriali; 4. Definizione e sviluppo di nuove politiche manutentive basate sull’estensione della letteratura scientifica grazie ai modelli teorici precedentemente verificati, per il miglioramento degli indici di efficienza; 5. Definizione di un nuovo modello per l’analisi delle performance di sistemi logistici quali gli Automated Storage/Retrieval Systems e comparazione con i modelli esistenti in letteratura. Il lavoro di tesi è stato sviluppato in stretta collaborazione anche con il Prof. Hoang Pham, direttore del Department of Industrial and Systems Engineering, Rutgers University, Piscataway – New Jersey (USA), grazie ad un periodo di ricerca di alcuni mesi svolto dall’autore presso Quality and Reliability Engineering Laboratory di tale dipartimento. Il presente lavoro ha portato anche alla pubblicazione di diversi contributi su importanti riviste e convegni internazionali, quali International Journal of Mathematics in Operational Research, International Journal of System Science e IEEE Transactions on Man, Cybernetics and Systems.

Thesis (PhD (Logistics))--University of Stellenbosch, 2011.<br>ENGLISH ABSTRACT: The design of a water distribution system (WDS) involves finding an acceptable trade-off between cost minimisation and the maximisation of numerous system benefits, such as hydraulic reliability and surplus capacity. The primary design problem involves cost-effective specifica- tion of a pipe network layout and pipe sizes (which are typically available in a discrete set of commercial diameters) in order to satisfy expected consumer water demands within required pressure limits. The problem may be extended to consider the design of additional WDS com- ponents, such as reservoirs, tanks, pumps and valves. Practical designs must also cater for the uncertainty of demand, the requirement of surplus capacity for future growth, and the hydraulic reliability of the system under different demand and potential failure conditions. A detailed literature review of exact and approximate approaches towards single-objective (minimum cost) WDS design optimisation is provided. Essential topics which have to be included in any modern WDS design paradigm (such as demand estimation, reliability quantification, tank design and pipe layout) are discussed. A number of formative concepts in multi-objective evo- lutionary optimisation are also reviewed (including a generic problem formulation, performance evaluation measures, comparative testing strategies, and suitable classes of metaheuristics). The two central themes of this dissertation are conducting multi-objective WDS design optimi- sation using metaheuristics, and a critical examination of surrogate measures used to quantify WDS reliability. The aim in the first theme is to compare numerous modern metaheuristics, in- cluding several multi-objective evolutionary algorithms, an estimation of distribution algorithm and a recent hyperheuristic named AMALGAM (an evolutionary framework for the simulta- neous incorporation of multiple metaheuristics applied here for the first time to a real-world problem), in order to determine which approach is most capable with respect to WDS design optimisation. Several novel metaheuristics are developed, as well as a number of new variants of existing algorithms, so that a total of twenty-three algorithms were compared. Testing with respect to eight small-to-large-sized WDS benchmarks from the literature reveals that the four top-performing algorithms are mutually non-dominated with respect to the vari- ous performance metrics. These algorithms are NSGA-II, TAMALGAMJndu, TAMALGAMndu and AMALGAMSndp (the last three being novel variants of AMALGAM). However, when these four algorithms are applied to the design of a very large real-world benchmark, the AMALGAM paradigm outperforms NSGA-II convincingly, with AMALGAMSndp exhibiting the best perfor- mance overall. As part of this study, a novel multi-objective greedy algorithm is developed by combining several heuristic design methods from the literature in order to mimic the design strategy of a human engineer. This algorithm functions as a powerful local search. However, it is shown that such an algorithm cannot compete with modern metaheuristics, which employ advanced strategies in order to uncover better solutions with less computational effort. The second central theme involves the comparison of several popular WDS reliability surro- gate measures (namely the Resilience Index, Network Resilience, Flow Entropy, and a novel mixed surrogate measure) in terms of their ability to produce designs that are robust against pipe failure and water demand variation. This is the first systematic study on a number of WDS benchmarks in which regression analysis is used to compare reliability surrogate measures with probabilistic reliability typically derived via simulation, and failure reliability calculated by considering all single-pipe failure events, with both reliability types quantified by means of average demand satisfaction. Although no single measure consistently outperforms the others, it is shown that using the Resilience Index and Network Resilience yields designs that achieve a better positive correlation with both probabilistic and failure reliability, and while the Mixed Surrogate measure shows some promise, using Flow Entropy on its own as a quantifier of re- liability should be avoided. Network Resilience is identified as being a superior predictor of failure reliability, and also having the desirable property of supplying designs with fewer and less severe size discontinuities between adjacent pipes. For this reason, it is recommended as the surrogate measure of choice for practical application towards design in the WDS industry. AMALGAMSndp is also applied to the design of a real South African WDS design case study in Gauteng Province, achieving savings of millions of Rands as well as significant reliability improvements on a preliminary engineered design by a consulting engineering firm.<br>AFRIKAANSE OPSOMMING: Die ontwerp van waterverspreidingsnetwerke (WVNe) behels die soeke na ’n aanvaarbare afruiling tussen koste-minimering en die maksimering van ’n aantal netwerkvoordele, soos hidroliese betroubaarheid en surpluskapasiteit. Die primere ontwerpsprobleem behels ’n koste-doeltreffende spesifikasie van ’n netwerkuitleg en pypgroottes (wat tipies in ’n diskrete aantal kommersiele deursnedes beskikbaar is) wat aan gebruikersaanvraag binne sekere drukspesifikasies voldoen. Die probleem kan uitgebrei word om die ontwerp van verdere WVN-komponente, soos op- gaardamme, opgaartenks, pompe en kleppe in ag te neem. Praktiese WVN-ontwerpe moet ook voorsiening maak vir onsekerheid van aanvraag, genoegsame surpluskapsiteit vir toekom- stige netwerkuitbreidings en die hidroliese betroubaarheid van die netwerk onder verskillende aanvraag- en potensiele falingsvoorwaardes. ’n Omvattende literatuurstudie word oor eksakte en benaderde oplossingsbenaderings tot enkel- doelwit (minimum koste) WVN-ontwerpsoptimering gedoen. Sentrale temas wat by heden- daagse WVN-ontwerpsparadigmas ingesluit behoort te word (soos aanvraagvooruitskatting, die kwantifisering van betroubaarheid, tenkontwerp en netwerkuitleg), word uitgelig. ’n Aantal basiese konsepte in meerdoelige evolusionˆere optimering (soos ’n generiese probleemformulering, werkverrigtingsmaatstawwe, vergelykende toetsingstrategie¨e, en sinvolle klasse metaheuristieke vir WVN-ontwerp) word ook aangeraak. Die twee sentrale temas in hierdie proefskrif is meerdoelige WVN-ontwerpsoptimering deur mid- del van metaheuristieke, en ’n kritiese evaluering van verskeie surrogaatmaatstawwe vir die kwantifisering van netwerkbetroubaarheid. Die doel in die eerste tema is om ’n aantal moderne metaheuristieke, insluitend verskeie meerdoelige evolusionere algoritmes en die onlangse hiper- heuristiek AMALGAM (’n evolusionere raamwerk vir die gelyktydige insluiting van ’n aantal metaheuristieke wat hier vir die eerste keer op ’n praktiese probleem toegepas word), met mekaar te vergelyk om sodoende ’n ideale benadering tot WVN-ontwerpoptimering te identi- fiseer. Verskeie nuwe metaheuristieke sowel as ’n aantal nuwe variasies op bestaande algoritmes word ontwikkel, sodat drie en twintig algoritmes in totaal met mekaar vergelyk word. Toetse aan die hand van agt klein- tot mediumgrootteWVN-toetsprobleme uit die literatuur dui daarop dat die vier top algoritmes mekaar onderling ten opsigte van verskeie werkverrigtings- maatstawwe domineer. Hierdie algoritmes is NSGA-II, TAMALGAMJndu, TAMALGAMndu en AMALGAMSndp, waarvan laasgenoemde drie nuwe variasies op AMALGAM is. Wanneer hierdie vier algoritmes egter vir die ontwerp van ’n groot WVN-toetsprobleem ingespan word, oortref die AMALGAM-paradigma die NSGA-II oortui-gend, en lewer AMALGAMSndp die beste resultate. As deel van hierdie studie is ’n nuwe meerdoelige gulsige algoritme ontwerp wat verskeie heuristiese ontwerpsmetodologiee uit die literatuur kombineer om sodoende die on- twerpstrategie van ’n ingenieur na te boots. Hierdie algoritme funksioneer as ’n kragtige lokale soekprosedure, maar daar word aangetoon dat die algoritme nie met moderne metaheuristieke, wat gevorderde soekstrategie¨e inspan om beter oplossings met minder berekeningsmoeite daar te stel, kan meeding nie. Die tweede sentrale tema behels die vergelyking van ’n aantal gewilde surrogaatmaatstawwe vir die kwantifisering van WVN-betroubaarheid (naamlik die elastisiteitsindeks, netwerkelastisiteit, vloei-entropie en ’n gemengde surrogaatmaatstaf ) in terme van die mate waartoe hul gebruik kan word om WVNe te identifiseer wat robuust is ten opsigte van pypfaling en variasie in aanvraag. Hierdie proefskrif bevat die eerste sistematiese vergelyking deur middel van regressie-analise van ’n aantal surrogaatmaatstawwe vir die kwantifisering van WVN-betroubaarheid en stogastiese betroubaarheid (wat tipies via simulasie bepaal word) in terme van ’n aantal toetsprobleme in die literatuur. Alhoewel geen enkele maatstaf as die beste na vore tree nie, word daar getoon dat gebruik van die elastisiteitsindeks en netwerkelastisiteit lei na WNV-ontwerpe met ’n groter positiewe korrelasie ten opsigte van beide stogastiese betroubaarheid en falingsbetroubaarheid. Verder toon die gebruik van die gemengde surrogaatmaatstaf potensiaal, maar die gebruik van vloei-entropie op sy eie as kwantifiseerder van betroubaarheid behoort vermy te word. Netwerkelastisiteit word as ’n hoe-gehalte indikator van falingsbetroubaarheid geidentifiseer en het ook die eienskap dat dit daartoe instaat is om ontwerpe met ’n kleiner aantal diskontinuiteite sowel as van ’n minder ekstreme graad van diskontinuiteite tussen deursnedes van aangrensende pype daar te stel. Om hierdie rede word netwerkelastisiteit as die surogaatmaatstaf van voorkeur aanbeveel vir toepassings van WVN-ontwerpe in die praktyk. AMALGAM word ook ten opsigte van ’n werklike Suid-Afrikaanse WVN-ontwerp gevallestudie in Gauteng toegepas. Hierdie toepassing lei na die besparing van miljoene rande asook noe- menswaardige verbeterings in terme van netwerkbetroubaarheid in vergeleke met ’n aanvanklike ingenieursontwerp deur ’n konsultasiefirma.

Doctor of Philosophy<br>Department of Agricultural Economics<br>Allen M. Featherstone<br>Bryan W. Schurle<br>The reliability of nine software packages using the maximum likelihood estimator for the logistic regression model were examined using generated benchmark datasets and models. Software packages tested included: SAS (Procs Logistic, Catmod, Genmod, Surveylogistic, Glimmix, and Qlim), Limdep (Logit, Blogit), Stata (Logit, GLM, Binreg), Matlab, Shazam, R, Minitab, Eviews, and SPSS for all available algorithms, none of which have been previously tested. This study expands on the existing literature in this area by examination of Minitab 15 and SPSS 17. The findings indicate that Matlab, R, Eviews, Minitab, Limdep (BFGS), and SPSS provided consistently reliable results for both parameter and standard error estimates across the benchmark datasets. While some packages performed admirably, shortcomings did exist. SAS maximum log-likelihood estimators do not always converge to the optimal solution and stop prematurely depending on starting values, by issuing a ``flat" error message. This drawback can be dealt with by rerunning the maximum log-likelihood estimator, using a closer starting point, to see if the convergence criteria are actually satisfied. Although Stata-Binreg provides reliable parameter estimates, there is no way to obtain standard error estimates in Stata-Binreg as of yet. Limdep performs relatively well, but did not converge due to a weakness of the algorithm. The results show that solely trusting the default settings of statistical software packages may lead to non-optimal, biased or erroneous results, which may impact the quality of empirical results obtained by applied economists. Reliability tests indicate severe weaknesses in SAS Procs Glimmix and Genmod. Some software packages fail reliability tests under certain conditions. The finding indicates the need to use multiple software packages to solve econometric models.

L’environnement urbain est fortement ancré dans la gestion des flux logistiques. La mutualisation de ces différents flux apporte alors une solution qualitative répondant aux critères environnementaux, économiques et sociétaux. Cette thèse propose une approche pour la mise en place des centres de distribution urbains (CDU) en combinant la logistique de distribution avec la logistique inverse (flux montants et flux descendants). L’objectif principal de ces CDU est d'assurer un développement durable dans les villes modernes. L’hétérogénéité des pratiques de la logistique de distribution et de la logistique inverse constitue le principal verrou scientifique. La mutualisation de ces différents flux apporte alors une solution qualitative et durable dès lors qu’elle répond aux critères attendus : environnementaux, économiques et sociétaux. Dans un contexte de logistique globale, nous nous sommes basés sur les problèmes de localisation de plateformes HLP « Hub Location Problem » afin de formuler le problème de localisation des CDU selon un critère de maximisation du profit par le choix du meilleur emplacement parmi ceux disponibles. Nous avons calculé les localisations partiellement possibles, tout en garantissant le traitement des flux retournés (collecte, tri, revente) et aussi en tenant compte des coûts socio-environnementaux. Par la suite, nous avons utilisé des outils de résolution du modèle proposé via des algorithmes d’optimisation. L’efficacité de ces algorithmes a été confirmée par un ensemble de jeux de données et de rapports d’analyse d’impacts. La dynamique liée à la fiabilité des CDU dans l’exécution du service par la prise en compte d’une politique de coordination inter-CDU fait aussi partie de notre étude. Nous nous sommes intéressés à l’aspect de disponibilité pour garantir les livraisons à temps. En effet, l’indisponibilité du système peut être due aux pannes aléatoires, aux actions de maintenance préventive planifiées, etc. Par conséquent, nous présentons une solution qui permet de satisfaire la demande journalière de manière ponctuelle par l’intégration d’une approche collaborative entre les différents sites. Il s’agit d’un modèle d’optimisation de la politique de coordination inter-CDU avec une stratégie de sous-traitance des livraisons en cas d’indisponibilité<br>The urban environment is strongly involved in the management of logistics flows. The pooling of these different flows provides a qualitative solution ensuring environmental, economic and societal criteria. The thesis objectives aim at supporting Urban Distribution Centers (CDU) by combining distribution logistics with reverse logistics (upstream flows and downstream flows), thereby ensuring sustainable development in modern cities. The heterogeneity of the distribution logistics practices and the reverse logistics define the core of this thesis. Sharing these different flows provides a qualitative and sustainable solution as long as it meets the aforementioned criteria (environment, economy and society). Our approach is based on the Hub Location Problem to formulate the location problem of UDC while maximizing the profit and choosing the best available location. We proceed by identifying potential available locations, while guaranteeing returned flows management (collection, sorting, resale, etc.) and reducing pollution impact. Moreover, we simulate our optimised model with simulation tools using optimization algorithms. The effectiveness of these algorithms are validated based on generated outputs (set of data) inspired by real world scenarios. Reliability is a part of this work when dealing with UDC deployment. The unavailability of the system may be due to random failures, planned preventive maintenance actions, etc. Therefore, we present a solution supporting daily demands by integrating a collaborative approach between different sites. This approach is based on inter-CDU coordination policy with a strategy of subcontracting deliveries dealing with unavailability

Health care systems in many countries are experiencing a growing demand while their resources remain limited. The discrepancy between demand and capacity creates many problems – long waiting times for treatment, overcrowding in hospital wards, high workload, etc. More efficient delivery of health care services can be achieved by better planning of its resources so that the mismatch between demand and capacity is minimized. Planning health care resources, including hospital resources, is difficult due to system complexity and variability in both resource availability and demand. Discrete-event simulation and other operational research methods can be used for solving planning problems in health care, and have been gaining increased attention from researchers during recent decades. Despite the growing number of academic publications, simulation appears to be less used in health care than in other application areas and only a small proportion of simulation studies is actually implemented. The aim of this thesis is to contribute to increased use of discrete-event simulation in hospital resource planning. The separate studies regarding intensive care unit capacity planning, operating room allocation strategies and the management of emergency patient flow in a radiology department highlight both the possibilities and the requirements for practical application of discrete-event simulation in hospital resource planning. The studies are described in five papers. In the first paper, the relationship between intensive care unit (ICU) occupancy and patient outcomes was investigated and the results showed that risk adjusted mortality was higher in the group of patients who were treated during high levels of occupancy. This indicates that appropriate planning of ICU resources is necessary to avoid adverse effects on patient outcomes. In the second paper, analysis of a relatively simple care chain consisting of two hospital departments – emergency and radiology – revealed a process that was not very well defined and measured. Investigation into data availability uncovered disparate information systems storing incompatible and fragmented data. It suggests that the current degree of process orientation and the current IT infrastructure does not enable efficient use of quantitative process analysis and management tools such as simulation. In the third paper, the value and possibilities of using simulation modelling in hospital resource planning were examined through the development and use of a simulation model for improved operating room time allocation and patient flow in a hospital operating department. The model was initially used for studying overcrowding in a post-anaesthesia care unit. Advanced planning logic implemented in the model enabled evaluation of several different scenarios aiming to improve the utilization of operating room resources. The results showed that it is possible to achieve slightly better and more even resource utilization, as well as provide greater flexibility in scheduling operations. In the fourth paper, a generic ICU model was developed and validated using data from four different hospital ICUs. The model was adapted and calibrated stepwise in order to identify important parameters and their values to obtain a match between model predictions and actual data. The study showed that in presence of high quality data and well defined process logic it is possible to develop a generic ICU simulation model that could provide accurate decision support for planning critical care resources. In the fifth paper, a number of factors that can contribute to successful implementation of simulation results in health care were identified. The timing of the simulation study must be right to support a critical decision, the benefit from implementation should clearly outweigh the cost of making the necessary changes and the model should be thoroughly validated to increase the credibility of the results. Staff involvement in simulation modelling activities, availability of good quality data, as well as proper incentives to improve the system contribute to implementation as well. These findings can help in establishing the conditions for successful implementation in future applications of simulation modelling in health care.<br>Hälso- och sjukvårdssystemen i många länder möter en växande efterfrågan samtidigt som resurserna är begränsade. När efterfrågan överstiger kapaciteten skapas många problem, bland annat långa väntetider för behandling, överbeläggningar i sjukhusavdelningar och hög arbetsbelastning för personalen. En effektivare sjukvård kan uppnås genom bättre planering av resurserna, så att obalansen mellan efterfrågan och kapacitet minimeras. Planering av hälso- och sjukvårdsresurser, inklusive sjukhusresurser, är svårt på grund av systemkomplexitet och variation i både resurstillgänglighet och efterfrågan. Simulering och andra operationsanalytiska metoder som används för att lösa planeringsproblem inom tillverkning, logistik och andra områden, kan med fördel användas också inom sjukvården och har fått ökad uppmärksamhet av forskare under de senaste årtiondena. Trots det växande antalet akademiska publikationer verkar simulering användas betydligt mindre inom sjukvården än i andra tillämpningsområden och endast en liten del av resultaten omsätts i praktiken. Syftet med denna avhandling är att bidra till ökad användning av simulering vid planering av sjukhusresurser. De separata studierna i avhandlingen behandlar kapacitetsdimensionering av intensivvård, allokering av operationssalsresurser samt hantering av akutpatientflödet på en röntgenavdelning, och lyfter därigenom fram både möjligheterna och kraven för praktisk tillämpning av diskret händelsesstyrd simulering för planering av sjukhusresurser. Intensivvårdsavdelningar anses vara bland de dyraste resurserna på ett sjukhus. Det är därför ekonomiskt önskvärt att ha en hög utnyttjandegrad av en sådan resurs. Samtidigt är det viktigt att alltid ha utrymme för kritiskt sjuka patienter. I en studie där förhållandet mellan beläggningen på intensivvårdsavdelningar och patientutfall undersöktes visade resultaten att riskjusterad dödlighet var högre för patienter som behandlades när beläggningen på avdelningen var hög, vilket understryker att bra planering av intensivvårdsresurser är mycket viktigt. Hög grad av processorientering och tillgång till data som möjliggör undersökning av patientflödet över gränserna av sjukhusets organisatoriska och funktionella enheter är exempel på förutsättningar för användning av simulering för hela vårdkedjor. En analys av en relativt enkel vårdkedja bestående av två sjukhusavdelningar avslöjade dock en process som inte var särskilt väldefinierad, och där olika informationssystem lagrade inkompatibla och fragmenterade data. Avsaknaden av processorientering och den befintliga IT-infrastrukturen är hinder för effektiv användning av kvantitativa processanalysverktyg som simulering. Värdet av att utnyttja simulering och modellering för planering av sjukhusresurser användes vidare för att hitta en bättre och jämnare fördelning av operationssalsresurser. Modellen användes för att undersöka ett antal scenarier och resultatet visade att det är möjligt att uppnå ett jämnare utnyttjande av operationssalar och en större flexibilitet vid schemaläggning av operationer. Generiska simuleringsmodeller, som med hjälp av ett antal parameterinställningar kan omvandlas till en ny modell av en given sjukhusenhet, skulle sannolikt öka användningen av simulering. Dock kan det vara svårt att visa hur dessa modeller avbildar varje specifik enhet på ett tillräckligt trovärdigt sätt. En generisk modell för kapacitetsdimensionering av intensivvårdsavdelningar har utvecklats och validerats med hjälp av data från fyra olika sjukhus. Studien visade att när data är av hög kvalitet och processlogiken är väldefinierad är det möjligt att utveckla en sådan generisk simuleringsmodell som kan ge beslutsstöd vid planering av intensivvårdsresurser. Flera litteraturundersökningar har visat att endast en liten del av publicerade simuleringsstudier inom sjukvården har implementerats. Genom att studera ett flerårigt simuleringsprojekt identifierades ett antal faktorer som kan bidra till att simuleringsresultat faktiskt används för att förändra verksamheten. Tidpunkten för simuleringsstudien måste vara välanpassad för att stödja ett kritiskt beslut, fördelar med förändringen bör tydligt överväga kostnaden för att genomföra den och modellen bör grundligt valideras för att öka resultatens trovärdighet. Personalens engagemang i modelleringsaktiviteter, tillgång till data av god kvalitet samt lämpliga incitament för att förbättra systemet bidrar också till genomförandet. Resultaten kan hjälpa till att skapa förutsättningar för framgångsrik framtida användning av simulering vid planering av sjukhusresurser.

Each year, billions of dollars are spent on missiles and munitions by the United States government. It is therefore vital to have a dependable method to estimate the reliability of these missiles. It is important to take into account the age of the missile, the reliability of different components of the missile, and the impact of different launch phases on missile reliability. Additionally, it is of importance to estimate the missile performance under a variety of test conditions, or modalities. Bayesian logistic regression is utilized to accurately make these estimates. This project presents both previously proposed methods and ways to combine these methods to accurately estimate the reliability of the Cruise Missile.

L’environnement urbain est fortement ancré dans la gestion des flux logistiques. La mutualisation de ces différents flux apporte alors une solution qualitative répondant aux critères environnementaux, économiques et sociétaux. Cette thèse propose une approche pour la mise en place des centres de distribution urbains (CDU) en combinant la logistique de distribution avec la logistique inverse (flux montants et flux descendants). L’objectif principal de ces CDU est d'assurer un développement durable dans les villes modernes. L’hétérogénéité des pratiques de la logistique de distribution et de la logistique inverse constitue le principal verrou scientifique. La mutualisation de ces différents flux apporte alors une solution qualitative et durable dès lors qu’elle répond aux critères attendus : environnementaux, économiques et sociétaux. Dans un contexte de logistique globale, nous nous sommes basés sur les problèmes de localisation de plateformes HLP « Hub Location Problem » afin de formuler le problème de localisation des CDU selon un critère de maximisation du profit par le choix du meilleur emplacement parmi ceux disponibles. Nous avons calculé les localisations partiellement possibles, tout en garantissant le traitement des flux retournés (collecte, tri, revente) et aussi en tenant compte des coûts socio-environnementaux. Par la suite, nous avons utilisé des outils de résolution du modèle proposé via des algorithmes d’optimisation. L’efficacité de ces algorithmes a été confirmée par un ensemble de jeux de données et de rapports d’analyse d’impacts. La dynamique liée à la fiabilité des CDU dans l’exécution du service par la prise en compte d’une politique de coordination inter-CDU fait aussi partie de notre étude. Nous nous sommes intéressés à l’aspect de disponibilité pour garantir les livraisons à temps. En effet, l’indisponibilité du système peut être due aux pannes aléatoires, aux actions de maintenance préventive planifiées, etc. Par conséquent, nous présentons une solution qui permet de satisfaire la demande journalière de manière ponctuelle par l’intégration d’une approche collaborative entre les différents sites. Il s’agit d’un modèle d’optimisation de la politique de coordination inter-CDU avec une stratégie de sous-traitance des livraisons en cas d’indisponibilité<br>The urban environment is strongly involved in the management of logistics flows. The pooling of these different flows provides a qualitative solution ensuring environmental, economic and societal criteria. The thesis objectives aim at supporting Urban Distribution Centers (CDU) by combining distribution logistics with reverse logistics (upstream flows and downstream flows), thereby ensuring sustainable development in modern cities. The heterogeneity of the distribution logistics practices and the reverse logistics define the core of this thesis. Sharing these different flows provides a qualitative and sustainable solution as long as it meets the aforementioned criteria (environment, economy and society). Our approach is based on the Hub Location Problem to formulate the location problem of UDC while maximizing the profit and choosing the best available location. We proceed by identifying potential available locations, while guaranteeing returned flows management (collection, sorting, resale, etc.) and reducing pollution impact. Moreover, we simulate our optimised model with simulation tools using optimization algorithms. The effectiveness of these algorithms are validated based on generated outputs (set of data) inspired by real world scenarios. Reliability is a part of this work when dealing with UDC deployment. The unavailability of the system may be due to random failures, planned preventive maintenance actions, etc. Therefore, we present a solution supporting daily demands by integrating a collaborative approach between different sites. This approach is based on inter-CDU coordination policy with a strategy of subcontracting deliveries dealing with unavailability

In the epoch of advanced mHealth (mobile health) use in ophthalmology, there is a scientific call for regulating the validity and reliability of eye-related apps. For a positive health outcome that works towards enhancing mobile-application guided diagnosis in joint decision-making between eye specialists and individuals, the aging population should be provided with a reliable and valid tool for assessment of their eye status outside the physician office. This interdisciplinary study aims to determine through hypothesis testing validity and reliability of a limited set of five mHealth apps (mHAs ) and through binary logistic regression the prediction possibilities of investigated apps to exclude the four major eye diseases in the particular demographic population. The study showed that 189 aging adults (45- 86 years old) who did complete the mHAs’ tests were able to produce reliable results of selected eye function tests through four out of five mHAs measuring visual acuity, contrast sensitivity, red desaturation, visual field and Amsler grid in comparison with a “gold standard” - comprehensive eye examination. Also, part of the participants was surveyed for assessing the Quality of Experience on mobile apps. Understanding of current reliability of existing eye-related mHAs will lead to the creation of ideal mobile application’ self-assessment protocol predicting the timely need for clinical assessment and treatment of age-related macular degeneration, diabetic retinopathy, glaucoma and cataract. Detecting the level of eye function impairments by mHAs is cost-effective and can contribute to research methodology in eye diseases’ prediction by expanding the system of clear criteria specially created for mobile applications and provide returning significant value in preventive ophthalmology.

För att kunna vara konkurrenskraftig är en hög leveranssäkerhet viktigt för många företag. Leveranssäkerhet är extra viktigt för logistikföretag därför att leverera i rätt tid och till rätt kvalitet utgör deras kärnverksamhet. Kunder kräver även hög leveranssäkerhet när de väljer sina leverantörer, vilket innebär att leveranssäkerhet blir ett krav för att ett företag ska anses som ett alternativ för kunden. Martin &amp; Servera Logistik är ett logistikföretag inom livsmedelsbranschen och hanterar cirka 6000 leveranser varje dag. De arbetar kontinuerligt med att förbättra sin leveranssäkerhet, vilket mäts i antal kundreklamationer. En del av dessa reklamationer uppstår på grund av avvikelser i transportprocessen, vilket leder till kvalitetsbristkostnader i form av returer och omarbeten.  Syftet med denna studie är att utreda problem och brister som kan uppstå i transportprocesser hos logistikföretag, specifikt inom livsmedelsbranschen. Studien syftar även till att ge exempel på förbättringar som kan implementeras för att höja leveranssäkerheten och minska kvalitetsbristkostnader. För att uppnå syftet har en fallstudie genomförts hos Martin &amp; Servera Logistik. Studien har bedrivits som ett Sex-Sigma projekt där problemlösningsmetoden DMAIC har använts. Akronymen DMAIC står för Define, Measure, Analyze, Improve och Control.  Projektet har inneburit analys av både kvantitativa och kvalitativa data. En litteraturstudie har genomförts för att förklara sambandet mellan leveranssäkerhet och kvalitetsbristkostnader och hur dessa kan påverkas med hjälp av processutveckling. Insamling av data har gjorts genom intervjuer och en fokusgrupp. Analys har genomförts med hjälp av metoder inom statistisk processtyrning, processkartläggning, och tematisk analys av intervjuer.  Från studien framkom att de vanligaste kvalitetsbristerna som uppstår i en transportprocess är olika former av transportskador samt att varor saknas vid leverans. Bland de vanligaste orsakerna till kvalitetsbrister som identifierades fanns feltemperering, krosskador och felplacerat gods. Exempel på förbättringsåtgärder för att höja leveranssäkerheten är att koppla orsakklassificeringar till specifika processaktiviteter, till exempel i ett avvikelsehanteringssystem.  Utifrån studiens resultat kan det konstaterats att minskade kvalitetsbristkostnader kan utgöra ett mått på ökad leveranssäkerhet, vilket kan uppnås genom kontinuerligt arbete med processutveckling. Baserat på tidigare studier kan det även konstateras att leveranssäkerhet kan bidra till minskat slöseri i transportprocesser och på så vis bidra till hållbar utveckling. Kravet på leveranssäkerhet för att förbli konkurrenskraftig kan därigenom användas som incitament för att utveckla företagets processer. Detta kan göras i syfte att minska kostnader, öka kundtillfredsställelse och bidra till hållbar utveckling.

Initially, we use the quadratic transmutation maps to compose a new probability model: the transmuted log-logistic distribution. Transmutation maps are a convenient way of constructing new distributions, in particular survival ones. It comprises the functional composition of the cumulative distribution function of one distribution with the inverse cumulative distribution (quantil) function of another. Its comprehensive description of properties, such as moments, quantiles, order statistics etc., along with its survival study and the classical and Bayesian estimation methods, are also part of this work. Focusing on analysis of survival, the study included two practical situations commonly found: the presence of regression variables, through the transmuted log-logistic regression model, and the presence of right censorship. In a second moment, searching for a more flexible model than the transmuted, we present its generalization, the transmuted distributions of cubic rank. Using the methodology presented in this first generalization, two models were considered to compose the new cubic transmuted distributions: the log-logistic and Weibull models. Faced with problems presented in the transmutated class of quadratic and cubic orders (such as the restricted parametric space of the transmutation parameter &lambda;), we propose in this work, a new family of distribution. This family, which we call e-transmuted or e-extended, is as simple as the transmuted model, because it includes a single parameter to the base model, but more flexible than the class of transmuted models, once the transmuted is a particular case of the proposed family. In addition, the nem family presents important properties such as, orthogonality between the baseline model parameters and the e-transmutation parameter, along with unrestricted parametric space for the &omega; e-transmutation parameter, which is dened on the real line. Simulation studies and real data applications were performed for all proposed models and generalizations.<br>Inicialmente, usamos os mapas de transmutação quadráticos para compor um novo modelo de probabilidade: a distribuição log-logística transmutada. Mapas de transmutação são uma forma conveniente de construção de novas distribuições, em especial de sobrevivência/confiabilidade, e compreendem a composição funcional da função de distribuição acumulada e da função de distribuição acumulada inversa (quantil) de um outro modelo. Uma descrição detalhada de suas propriedades, tais como, momentos, quantis, estatística de ordem, dentre outras estatísticas, juntamente com o estudo de sobrevivência e métodos de estimação clássico e Bayesiano, também fazem parte deste trabalho. Focando em análise sobrevivência, incluímos no estudo duas situações práticas comumente encontradas: a presença de variáveis regressoras, através do modelo de regressão transmutado log-logístico, e a presença de censura à direita. Em um segundo momento, buscando um modelo mais flexível que o transmutado, apresentamos uma generalização para esta classe de modelos, as distribuições transmutadas de rank cúbico. Usando a metodologia apresentada nesta primeira generalização, dois modelos foram considerados para compor as novas distribuições transmutadas cúbica: os modelos log-logístico e Weibull. Diante de problemas apresentados na classe transmutada de ordens quadrática e cúbica (tal como o espaço paramétrico restrito do parâmetro de transmutação &lambda;), propomos neste trabalho, uma nova família de distribuição. Esta família, a qual chamamos e-transmutada ou e-extendida, é tão simples quanto o modelo transmutado, por incluir um único parâmetro ao modelo base, porém mais flexível do que a classe de modelos transmutados, sendo esta classe um caso particular da família proposta. Além disso, apresenta propriedades importantes, como ortogonalidade entre os parâmetros do modelo base e o parâmetro de e-transmutação, e espaço paramétrico não restrito para o parâmetro de etransmutação &omega;, que é definido em toda reta real. Estudos de simulação e aplicações a dados reais foram realizados para todos os modelos e generalizações propostas.

Syfte: Syftet med studien är att undersöka vilka faktorer som påverkar projektering av en järnvägsanläggning ur ett livscykelperspektiv. Målet är att tydliggöra vad Trafikverket behöver ta hänsyn till vid projektering av en järnvägsanläggning Syftet med studien är att undersöka vilka faktorer som påverkar projekteringen av järnvägsanläggningar utifrån ett Life Cycle Managementlångsiktigt hållbarhetsperspektiv perspektiv med fokus en centralpunkt inom på Integrated Logistic Support. Med detta avser studien att ge förslag på för atthur organisationen kunnakan uppnå långsiktiga lönsamhetsmål de krav som ställs på järnvägsanläggningen samt öka förutsägbarheten för livscykelkostnaden. Frågeställningar: Hur kan projektering av järnvägsanläggningar förbättras ur ett långsiktigtlivscykel perspektiv? Vilka faktorer behöver Trafikverket ta hänsyn till vid projekteringsfasen för att säkerställa tillförlitliga och kostnadseffektiva järnvägsanläggningar? Hur kan en arbetsmetodik formas för att främja en kostnadseffektiv järnvägsanläggning? Metod: Följande studie är baserad på en kvalitativ fallstudie av Trafikverket. Metoden är baserad på semistrukturerade intervjuer och dokumentationsmetodik för att erhålla empiriska data. Litteraturstudien och det teoretiska ramverket är baserade på expertgranskade tidskrifter, vetenskapliga artiklar och böcker som täcker studieområdena. Slutsats: Studien har visat att projektering av järnvägsanläggningar ur ett livscykelperspektiv kan förbättras genom att ta fram konkreta underlag för stödja de besluts som ska tas. Beslutsunderlag för järnvägsanläggningen bör baseras på olika analyser för att kunna värdera vilket alternativ som ger den mest kostnadseffektiva anläggningen samtidigt som det återspeglar de efterfrågade målen och kraven. Analyser ska inte enbart baseras på tekniska konstruktion utan även driften samt underhållet behöver beaktas eftersom de har en stor inverkan på utfallet av kapaciteten, prestandan samt kostnaderna över hela anläggningens livscykel. Vidare har studien visat vikten av att ha tillförlitliga system som kan ge information om anläggningen och även all data som krävs för att utföra analyser.<br>Purpose: The purpose of the study is to investigate which factors affect the longlife cycle-term planning of a railway infrastructure. The aim is to clarify what the Swedish Transport Administration needs to take into account when planning a railway infrastructure in the future in order to meet the requirements and increase the predictability of life cycle costs. Research questions: How can railway infrastructure planning phase be improved based on a life cycle long-term perspective? What factors do the Swedish Transport Administration need to take into account during the planning phase to ensure reliable and cost-effective railway infrastructure? How can a working methodology be designed to promote a cost-effective railway facility? Method: The following study is based on a qualitative case study of Swedish Transport Administration. The literature study and the theoretical framework are based on peer-previewed journals, scientific articles and books that covers the areas of the study. The empirical data collection is based on semi-structured interviews and reports from different administrative authority. Conclusion: This study has shown that planning of railway infrastructure from a life cycle perspective can be improved by concrete evidence to support the decisions to be taken. The decisions basis for the railway infrastructure should be based on various analysis in order to evaluate the most cost-effective option while reflecting the desired goals and requirements. However, analysis should not only be based on the technical design. It should also consider operation and maintenance, since they have a major impact on the outcome of capacity, performance and cost throughout the life cycle of the railway infrastructure. Furthermore, the study has demonstrated the importance of having reliable systems that can provide information about the railway infrastructure and all data required for carrying out analysis.

En fiabilité et en analyse de survie, les distributions qui ont une fonction de hasard unimodale ne sont pas nombreuses, qu'on peut citer: Gaussienne inverse ,log-normale, log-logistique, de Birnbaum-Saunders, de Weibull exponentielle et de Weibullgénéralisée. Dans cette thèse, nous développons les tests modifiés du Chi-deux pour ces distributions tout en comparant la distribution Gaussienne inverse avec les autres. Ensuite nousconstruisons le modèle AFT basé sur la distribution Gaussienne inverse et les systèmes redondants basés sur les distributions de fonction de hasard unimodale<br>In reliability and survival analysis, distributions that have a unimodalor $\cap-$shape hazard rate function are not too many, they include: the inverse Gaussian,log-normal, log-logistic, Birnbaum-Saunders, exponential Weibull and power generalized Weibulldistributions. In this thesis, we develop the modified Chi-squared tests for these distributions,and we give a comparative study between the inverse Gaussian distribution and the otherdistributions, then we realize simulations. We also construct the AFT model based on the inverseGaussian distribution and redundant systems based on distributions having a unimodal hazard ratefunction

碩士<br>中原大學<br>工業與系統工程研究所<br>104<br>In a world with globalized economy and trade liberalization, companies need to consider how to reduce operating costs and meet customer needs to improve customer satisfaction. It will be the key issue whether enterprises can have sustainable development and operations. Network planning has been widely used in many web systems, where logistics network reliability, the ability to complete logistics services at a specified time and conditions is a key issue. The logistics network design is one of the core problems in supply chain management, under the circumstances of demand uncertainty on the distribution of a variety of goods. In this study, the road traffic randomness is the road traffic with no clear path, which will also affect the on-time delivery in logistics. A model was presented and a numerical example was illustrated. The results showed that the low smooth reliability does not affect the delivery reliability and cost of transportation.

碩士<br>中原大學<br>工業工程研究所<br>95<br>With the global eco-awareness, the European Union has claimed several regulations, such as the Directive on Waste Electrical and Electronic Equipment (WEEE). Some authors think that the regulations of environment and product packing have urged business to focus on a certain issue, such as the problem of waste. In addition, with the popularity of the green supply chain, the concept of reducing waste has forced business paying more attention to the recycling of waste. However, the management of the green supply chain is more complex than traditional management of supply chain, because it has a lot of uncertain risks that recovery point can hardly control. The uncertainty is caused by customers who supply the returned product in the reverse supply chain; and it is quite difficult to forecast when the customers will discard products and whether the quality of the returned production can be recovered or not. The recovery point consequently wastes a great deal of resources and cost in the uncertainty factors which include the quantity of collection, lead time and quality. For this reason, the research will make efforts in control the uncertainty under the framework of reverse supply chain. We expect to employ the concept of reliability management to estimate the number of returned products with the acceptable quality for the business. Then, according to the capacity of collection center and the amount of whole returned product in the reverse logistic, we can formulate a integer nonlinear program that contain purchase cost, fixed cost and inventory cost to conjecture which collection point we can form a good partnership. Consequently, the concept of this research will include reliability theory and purchase cost to solve the uncertainty issue. By using the proposed model, managers can make decisions more correctly.

碩士<br>國立臺灣科技大學<br>工業管理系<br>106<br>In real world, logistics systems are often used to characterize the distribution of multi-commodity with multiple sources and sinks within the promised time constraint. Moreover, network has been adopted extensively in many real-world systems. This thesis focuses on a logistics network with suppliers, distribution centers, or regions, and routes. In the region, numerous retailers and demand requirement are contained. The available capacity on each route is stochastic and multistate because the capacity may be partially reserved by other customers, and the logistics network can be regarded as a multistate multi-commodity logistics network (MMLN). This thesis is mainly to evaluate network reliability. Such network reliability can be treated as a logistics performance index. We consider the total delivery time consisting of travel time, service time, and distribution time, where service time contains unloading, picking, and loading time, and the time when vehicles arrive at distribution center should be within the time window. An algorithm is firstly proposed to calculate network reliability and a practical case of convince store logistics system is presented to emphasize the managerial implication of network reliability. Moreover, a model is further extended to each supplier has a variety of commodities to delivery, and an algorithm is further developed in terms of minimal paths to evaluate the network reliability. From the decision-making viewpoint, supervisors can evaluate network reliability by proposed algorithms and treat it as a capability indicator to know whether MMLN satisfies demand within a time constraint and make decisions.

碩士<br>國立臺灣科技大學<br>工業管理系<br>104<br>Network structures have been diffusely adopted in logistics systems where the delivery to be completed within the promised time frame is specifically the most critical target. This paper focuses on a multistate intermodal logistics network (MILN) with transit stations, cargo terminals and routes. Along each route, there is a carrier whose available containers is multistate because the containers could be occupied by other customers. Besides, the delivery time consisting of service time, travel time, and waiting time varies with the number of containers and the type of vehicle. The arrival time at cargo terminal should be within the time window which is the interval between the earliest and latest acceptable arrival time. This paper is mainly to evaluate network reliability. Such network reliability can be treated as a delivery performance index. An algorithm is then proposed in chapter 3 to calculate network reliability and a practical case of starting motor distribution between Taiwan and China is presented to emphasize the managerial implication of network reliability. Moreover, commodities may be spoilt during delivery due to traffic accidents, collisions, natural disasters, weather, etc., and thus the intact commodities may not satisfy the market demand. An algorithm is further developed in chapter 4 to find the network reliability, the probability that the MILN can successfully deliver sufficient commodities to meet market demand under the time windows and delivery spoilage. Same case is utilized to illustrate the proposed algorithm. From the decision-making viewpoint, supervisors can evaluate network reliability by proposed algorithms and presented to emphasize the management implication.

On-time delivery performance has become an imperative in serving digital consumers and a key dimension for assessing overall supply chain reliability within the context of e-fulfillment. As part of a four-month internship program at Nike’s European Logistics Campus (ELC), in Laakdal, Belgium, the goal of this thesis is understanding the root causes behind Nike’s failed delivery performance to consumer by mapping and reviewing the company’s end-to-end digital order lifecycle. Following the analysis of a restricted sample of Nike.com orders for shipping destinations in BeNeLux and their aggregate performance through the end-to-end process, the primary sources of failure within Nike’s order flow are identified and short-term recommendations are made for improving delivery performance to consumer.

碩士<br>淡江大學<br>會計學系<br>93<br>The use of enterprise resource planning (ERP) system is strategic necessity of a company. Under the electronic and functional integrity environment, the departmental boundaries have become blurred. Therefore, the internal control mechanism designed for traditional departmental duty segregations has no longer valid. If a company can understand the control points embedded in an ERP system before implementing it, then the company may be able to avoid the system deficiency and incompetence, causing the dysfunctional decision-making or losing reliability of the financial reporting.The research applied case study to investigate the process of logistics module in a selected ERP system. It also observed whether the control mechanism embedded in the module would affect the reliability of financial reporting. Finally, the research investigated whether the case ERP system had lacked of some critical control mechanism, and the related solutions.The research findings suggest that the adequate parameter setting of an ERP system is the most crucial control mechanism for assuring data integrity, accuracy and validity. Moreover, the design of control mechanism has altered. Instead of departmental control mechanisms, the ERP system had provided a role base or task base control mechanism. Finally, the voucher number assigned by the ERP system is differed from those common accounting systems, which usually assign sequential numbers to vouchers. However, this process has no significant impact on the reliability of financial reporting.

Safety of the airborne platforms rests heavily on the way they are maintained. This maintenance includes repairs and testing, to reduce platform down time. Maintenance is performed using generic and specific test equipment within the existing maintenance management system (MMS). This thesis reports the work undertaken to improve maintainability and availability of avionics systems using an intelligent decision support system (IDSS). In order to understand the shortcomings of the existing system, the prevalent practices and methodologies are researched. This research thesis reports the development and implementation of an IDSS and the significant improvements made by this IDSS by integrating autonomous and independent information sources by employing a multi-agent system (MAS). Data mining techniques and intelligence agents (IA) are employed to create an expert system. The developed IDSS successfully demonstrates its ability to integrate and collate the available information and convert into valuable knowledge. Using this knowledge, the IDSS is able to generate interpreted alerts, warnings and recommendations thereby reasonably improving platform maintainability and availability. All facets of integrated logistics support (ILS) are considered to create a holistic picture. As the system ages, the IDSS also matures to assist managers and maintainers in making informed decisions about the platform, the unit under test (UUT) and even the environment that supports the platform.

碩士<br>中原大學<br>工業與系統工程研究所<br>105<br>With the development of online shopping, consumer behavior patterns have changed a lot, and shopping of consumers no longer limited to the traditional way. Through the online shopping platform, consumers can use their smart phone, tablet or computer to purchase products online in any network. Convenient consumption patterns, not only become consumers benefit, but also become business opportunities. In recent years, with the rise of consumer awareness, customer satisfaction has become one of the primary goals. In the meantime, the issue of logistic network distribution becomes extremely important. Over the past few years. many studies have applied the concept of reliability into the logistic network to see if the products can be delivered to customers on time. This study explores travel time through the randomness of road traffic and capacity, and constructs a capacity reliability model and integrates the vehicle routing problem. Comparing with the traditional shortest path model, the model with reliability is better than the shortest path model with the distribution time.

Competitive and high-risk environments require complex high technology systems, which need to be supported and maintained over their respective life cycles. These systems often have a significant consequence of failure, and require complex management systems to achieve their operational objectives. Significant leadership and management challenges exist, not only in South Africa, but also in other developing countries, where systems may be utilised beyond the lifespan they were designed for and are susceptible to obsolescence. This study was conducted by following a structured process; the research consisted of three stages. The first stage dealt with the research problem, including the delimitations of the study. The second stage was further divided into three phases. The first phase deconstructed the appropriate literature, which included the interpretation of numerous definitions of logistics, integrated logistics support, and the integrated logistics support elements. In addition, the research was grounded in the fields of operations management, supply chain management and integrated logistics support. The second phase focused on the deconstruction of six case studies from four different high technology complex systems. From the analysis of the first two phases followed the third phase of research, which focused on the identification of areas requiring further research. Further research was conducted by means of a questionnaire, the results of which were analysed for variable dependency and variable association. The third stage of the research included the collation and analysis of the findings of the first two stages of research. The analysis utilised the principles of Mode 2 research and design science research, whereby an ILS framework and associated grounded technological rules have been recommended. These recommendations are robust in nature, as they can be applied in the most challenging environment and circumstances as identified. Furthermore, by grounding the theory in the disciplines of operations management, supply chain management and integrated logistics support, the reliability, validity, relevance, and applicability of the study could be substantiated. This implied that the generated theoretical knowledge could be transferred to and applied in practice, and as such, an organisation can reap substantial value added benefits, and gain considerable competitive advantage in the market place by applying this developed ILS framework and associated ILS grounded technological rules.<br>Business Leadership<br>D. BL.

碩士<br>國立中央大學<br>機械工程研究所<br>100<br>This present paper mainly discusses practicality of the Logistic-based reliability model. By result of fitting data knows that the model is accurate, and carries on the fitting by the random selection part of data to examine the sensitivities and reappearance of completed data. Distribution of incomplete data could be catches on important to sampling data and formulate the standard. It could display the reliability of completed data precisely as the data pass through the inflection point. When the life test comes to inflection point may consider stopping collect data. Based on Logistic-based model to discuss the complex system by influence of parameter adjustment and following.

碩士<br>國立政治大學<br>資訊管理研究所<br>91<br>Since the late 80s, due to the tensive pressures from globalization, customer demands, uncertainties, IT innovation, as well as the shorter product life cycle, businesses were struggling in how to quick response customer desires, in an effort to retain their niches. As a consequence, Global Logistic (GL), in turn, becomes the sharp weapon in this regard. Literature studied GL from various perspectives. Among these studies, Vidal & Goetschalckx compared models in previous studies, and came up with three major challenges in this area：(1) uncertainty was not taken into account; .(2) restrictions of the BOM structure are not clearly dealt with; and (3) key financial factors of internationalization, such as the exchange rate and taxes, were not modeled. Hence, in order to deal with such problems, Vidal & Goetschalckx carried on the analysis on the effects toward key factors of GL and total cost minimization by modeling the factor of suppliers’ reliability in their study. However, in Vidal & Goetschalckx‘s study, there was no further concerns of uncertainties on other players in the logistic system. Fu-Cang Wu takes uncertainties into account on the players of forward logistic system. As a consequence, this research aims to extend Vidal & Goetschalckx’s modus. In the mathematic model, this study adds the settings of reliabilities on players either in the forward logistics or in the reverse logistics. Besides, two operation modes are provided in the model：(1) seeking minimum cost on a target of system reliability; and (2) seeking maximum system reliability on a target of cost. Then, this research makes use of the Fault Tree Analysis (FTA) for in depth analysis on reliability patterns. Finally, a methodology is established, which provides decision makers a reference basis, whenever he or she needs to place a global logistics system. Via the use of this prototype, it is believed to have a good mechanism for finding out the key influence factors of the reliability, enhancing buyer-seller relationships, and ensuring the goal of total cost minimization

Hurricanes are a threat to power and telecommunication infrastructure. This work summarizes a method for hurricane characterization using the proposed Localized Tropical Cyclone Intensity Index(LTCII) as a model for estimating damages to Electric power infrastructure. The model considers the effect of storm surge, maximum sustained wind speeds, the duration of time for which the system has been under tropical storm conditions and the area swept by hurricane over land. The measurements focus on major load centers in the system. The validation of the outage data is discussed. The model is evaluated for hurricanes from 2004, 2005 and 2008 hurricane seasons. The degree of influence of various hurricane parameters on the damages suffered by electric power systems are discussed using case studies. The maximum outages are observed to follow a logistic regression curve with respect to log(LTCII), with a correlation of 0.85. The observed restoration times fit a 6th degree polynomial with an R2 = 0.6. The effects of time under tropical storm winds were observed to have great significance in the damage profile observed with the model.<br>text

碩士<br>元智大學<br>工業工程與管理學系<br>94<br>With the continuous rapid leaps and changes of technology development, the technical products need to shorten their lifecycle in order to meet the requirements of markets. Still, the army weapons and equipment have to take into account all special uses and strict quality control for military specifications, which are totally different with the commercial products, just aiming at the stable and serviceable needs. The army electrical systems include lots of complicated accessories and parts. The operational availability, maintenance cost, and all restricted factors need to be evaluated appropriately to keep the systems in good working order. Especially, for some projects limited by political, and critical technical factors need to acquire the Mean Time between Failure (MTBF), failure rate (λ), and operational availability through the malfunction records of mid-long term in order to get the optimum method and review the equipment failure trend regularly to enact proper purchasing plan previously and support the equipment maintenance under the retrenched budget. This study, based on existing product failure records, is to calculate the critical parts’ failure rate, operational availability, mean time between failure data with some easy methods in accordance with fault-tree analysis. And, under the consideration of cost and operational availability, we can make a decision to contract with a local qualified contractor to build depot maintenance ability or ship the failure parts back to their original producers for maintenance. Furthermore, it could provide an easy evaluation method for the maintenance units of air base to decide the appropriate and optimum logistics supply operations in order to support readiness missions.

<p>Technology has become increasingly more prevalent in all aspects of society since the age of the computer. The United States Military has successfully integrated the powerful processing capabilities of computers to increase the proficiency and lethality of its Soldiers, Sailors, Marines, and Airmen. However, this increased lethality comes at risk due to the inherent vulnerabilities of computer systems to spyware, malware, and counterfeit components. Inspired by the ability of canines to seek out and find electronic devices, this research sought methods to characterize components by their “scent” using precise analytical tools. Using these tools, this thesis sought to develop and utilize non-invasive methods to show proof-of-concept for electronic device classification by volatile compounds unique to different types of components. The findings of this research proved that electronic components that vary by age, origin, type, or manufacturer emit different volatile compounds available for detection using modern two-dimensional gas chromatography and solid-phase microextraction technologies. If developed further, the methods used in this research have the potential for application in the United States Department of Defense to ensure that all electronic components installed in their systems are authentic, come from a trusted source, and can be relied upon in even the most stressful operating conditions.</p>