• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 38
  • 8
  • 8
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 70
  • 33
  • 32
  • 21
  • 17
  • 17
  • 15
  • 11
  • 9
  • 8
  • 6
  • 6
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Analysis of Stochastic Disruptions to Support Design of Capacitated Engineered Networks

Uribe-Sánchez, Andrés Fernando 19 October 2010 (has links)
This work is a compilation of four manuscripts, three of which are published and one is in the second round of review, all in refereed journals. All four manuscripts focus on analysis of stochastic disruptions to support design of capacitated engineered networks. The work is motivated by limited ability to mitigate elevated risk exposure of large-scale capacitated enterprise networks functioning in lean environments. Such inability to sustain enterprise capacity in the face of disruptions of various origins has been causing multi-billion enterprise forfeitures and hefty insurance premiums. At the same time, decision support methodologies for reliable design of dynamic capacitated networks have been largely unavailable. This work is organized as follows. Paper 1 presents a methodology to analyze ca- pacitated healthcare supply chains using a framework of forward ow-matching networks with multiple points of delivery. Special emphasis is given to developing stochastic models for capturing capacity trajectories at the points of delivery. Paper 2 focuses on assuring capacity availability for a critical vertex exposed to random stepwise capacity disruptions with exponentially distributed interarrival times and uniformly distributed magnitudes. We explore two countermeasure policies for a risk-neutral decision maker who seeks to maxi- mize the long-run average reward. We present an extensive numerical analysis as well as a sensitivity study on the uctuations of some system parameter values. Paper 3 extends the capacity assurance analysis for critical vertices by considering stepwise partial system capacity loss accumulating over time. We examine implementation of a countermeasure policy, aimed at reducing the disruption rate, for a risk-neutral decision maker who seeks to maximize long-run average return. We explore how the policy of maintaining the optimal disruption rate is aected by a number of system parameters. Finally, Paper 4 presents a dynamic predictive methodology for mitigation of cross-regional pandemic outbreaks which can be used to estimate workforce capacity loss for critical vertices due to such societal disasters.
22

Begreppslig validering : av ett ledarskapstest

Forsberg Ekdal, Linda January 2018 (has links)
Ledin (2002) har skapat ett arbetspsykologiskt ledarskapstest där han använder sig av olika scenarion för att beskriva olika påståenden. Syftet med mitt arbete är att validera Ledins faktornamn genom att jämföra de faktornamn Ledin använt, med de faktornamn jag skapat genom en begreppsanalys. Finns det några likheter respektive skillnader mellan faktornamnen? Detta undersöktes med en kvalitativ enkät som besvarades av tio studenter. Försökspersonen fick ange ett gemensamt begrepp för ett antal punkter som berörde en ledares reaktioner i en störd mötessituation. Elva uppsättningar punkter med reaktioner skulle förses med varsitt begrepp. De föreslagna begreppen analyserades med hjälp av Svenska akademins ordbok för att finna den ursprungliga betydelsen. När begreppen sammanställts var ett faktornamn funnet. Tre faktornamn motsvarar kognitioner, tre faktornamn motsvarar emotioner och fem faktornamn motsvarar beteenden. Ledins och mina faktornamn har liknande betydelser, skillnader gäller hur smala betydelserna är och de påverkas även av att en betydelse beror av situation och miljö. Därmed är Ledins (2002) faktornamn validerade. / Ledin (2002) has created a work psychological leadership test where he uses different scenarios to explain different statement. The purpose of my work is to validate Ledin’s factor names by comparing the factor names used by Ledin with those created by me through a concept analysis. Are there any similarity or difference between the factor names? This was examined with a qualitative questionnaire that was filled in by ten students. The subject was asked to suggest a common concept for a number of statements concerning leader’s in a disturbed meeting situation. Concepts were assigned to eleven sets with reactions. The concepts were analysed with Svenska akademins ordbok in order to identify the original definitions. When the concepts had been compiled a factor name was specified. Three factor names correspond to cognitions, three correspond to emotions and five factor names correspond to behavior. Ledin’s and my factor names have similar meanings, the differences have to do with how narrow the meanings are and they are also affected by the impact on a meaning from the situation and context. Thus, Ledin’s (2002) factor names are validated.
23

Previsão das Instabilidades de Disruptura através de Redes Neurais Artificiais / Forecasting disruptions Instabilities by artificial neural networks

Kenya Andrésia de Oliveira 25 February 2000 (has links)
Redes neurais artificias, tipo \"feedforward\", de duas camadas, foram utilizadas neste trabalho para fazer previsões das instabilidades de disruptura que surgem nas descargas de plasma do tokamak TEXT (E.U.A.), obtendo-se resultados bastante encorajadores. Verificou-se que uma arquitetura de rede, do tipo m:2m:m:1, onde m é dimensão de imersão do atrator do sistema dinâmico em estudo, costuma ser um bom chute inicial para a escolha da arquitetura ideal de trabalho, que costuma ser livre e, não raro, trabalhosa. Utilizando-se, em sinais de raios-X, uma rede neural artificial com arquitetura 15:30:15:1, por exemplo, conseguiu-se fazer previsões com uma antecipação de até 4 ms das instabilidades de disruptura, tempo quatro vezes maior do que o obtido utilizaudo-se sinais magnéticos das bobinas de Mirnov. Tal antecipação é bastante significativa e abre a possibilidade de, no futuro, utilizarem­se mecanismos de defesa da máquina, tais como injeção de partículas neutras (ou\"pellets\"), aplicação de campos magnéticos externos, etc, no sentido de se tentar evitar a ocorrência destas instabilidades, ou, pelo menos, minimizar os seus efeitos nocivos. Isto certamente contribuirá significativamente para a viabilização dos futuros reatores de fusão à plasma. Finalmente, o sistema de diagnóstico de raios-X de baixas energias do tokamak TCABR, que foi projetado e já se encontra em fase de instalação para fornecer sinais que servirão para alimentar a rede neural, também possibilitará a reconstrução tomográfica das regiões de mesma emissividade da coluna de plasma. A análise tomográfica, utilizando-se os sinais de dois conjuntos de detectores de raios-X moles, também será muito útil na investigação dos mecanismos físicos que dão surgimento às instabilidades de disruptura, além de permitir, ainda, a medida da temperatura eletrônica do plasma, através do método dos absorvedores. / Two-layer feedforward neural network has been used in this work to forecast the disruptive instabilities that occur in the TEXT tokamak plasma discharges. For this task, soft X-ray experimental signals were used with very promising results. It was verified that a neural net with an architecture of the type m:2m:m:1, where m is the embedding dimension of the atractor of dynamical system in focus, is usually a good initial guess in the searching process of finding the ideal architecture. A neural network with architecture 15:30:15:1 was capable, for example, to forecast the disruptive instabilities up to 4 ms in advance. This period of time is four time larger than the one obtained when magnetic signals from Mirnov coils were used. This forecasting time is quite significative and opens up the possibility of using defensive mechanisms, such as the injection of neutral particles (or pellets), the application of external magnetic fields, etc, with the objective of avoiding the occurrence of the disruptions or, at least, to minimize their harmful effects. This achievement certainly would be an important contribution to the development of the next generation fusion devices. Finally, the soft X-ray diagnostic system for the TCABR was projected and it is already being installed. This system will provide experimental signals that will be analyzed by neural networks and will be also used to identify, through tomografic image reconstructions, the regions of the plasma that have the same soft X-ray emissivity. The tomography analysis of the plasma, that will be carried out by using the signals of two soft X-ray detectors arrays, will be also very usefull for investigating the triggering mechanism of disruptions and will also allow the determination of the plasma electron temperature through the two foil absorbing method.
24

Manufacturing Companies' Strategies to Mitigate Supply Chain Disruptions

Benton, Vanessa Kaye 01 January 2019 (has links)
Supply chains have become increasingly unstable due to unanticipated disruptive events, which undermines a firm's capacity to achieve a competitive market advantage and increase profitability. The disruption of a supply chain is essential to supply chain managers, as the interruption can be expensive, and the goods and services lost can negatively affect the entire supply chain. The purpose of this qualitative multiple case study was to explore strategies that manufacturing firm managers use to mitigate supply chain disruptions to remain profitable. The population consisted of 4 supply chain managers from 2 manufacturing firms located in the southern region of eastern Virginia. The conceptual framework for this study was the contingency theory of fit. Data were collected from semistructured interviews, company documents, and publicly available information. Based on the thematic data analysis, 3 emergent themes developed as collaboration and information sharing, information technology and supply chain risk, and use of multiple suppliers. The implications for positive social change include potential increased employment opportunities and salaries, investments in community projects, and enhanced consumer spending in the local community, thereby raising the standard of living and social well-being of local community residents.
25

Riskhantering i försörjningskedjan – ur ett inköpsperspektiv

Markusson, Josef, Ahlberg, Henrik January 2020 (has links)
Försörjningskedjor har blivit allt mer globala, vilket har medfört att risken ökat och allt fler oförutsedda händelser uppstår som kan påverka organisationen på ett negativt sätt. Denna studies syfte var att få en förståelse för hur företag A hanterar och identifierar risker inom försörjningskedjan utifrån ett inköpsperspektiv, vilket undersöktes med hjälp av kvalitativa metoder. Studien började med insamling av allmänna fakta för att skapa en bild över potentiella problem inom försörjningskedjan, vidare riktades den teoretiska referensramen in på teorier och modeller inom riskdefinition, riskstrategier och analysverktyg för riskbedömning. Sedan genomfördes en fallstudie av hur företag A upplever risker. Den empiriska datan blev insamlad genom semi-strukturerade intervjuer med individer på företagets inköpsavdelning, med fokus på hur de identifierar och hanterar risker. Därefter analyserades den insamlade datan från intervjuerna, utifrån den teoretiska referensramen. Resultatet visade att det finns en stor riskförståelse och aktivt arbete mot olika typer av risker, samt för att minimera störningar är den främsta åtgärden kommunikation med leverantörer. I studien framkom även att det inte finns någon enhetlig riskstrategi och riskhantering bland individerna på inköpsavdelningen, istället hanteras riskerna utifrån enskilda situationer. / Supply chains have become increasingly global, which has led to increased risk and more and more unforeseen events occurring that could adversely affect the organization. The purpose of this study was to gain an understanding of how Company A manages and identifies risks in the supply chain from a purchasing perspective, which was investigated using qualitative methods. The study began with the gathering of general facts to create a picture of potential problems in the supply chain, and the theoretical frame of reference was also focused on theories and models within risk definition, risk strategies and analysis tools for risk assessment. A case study was then conducted of how Company A perceived risks. The empirical data was collected through semi-structured interviews with individuals in the company's purchasing department, focusing on how they identify and manage risks. Subsequently, the data collected from the interviews were analyzed based on the theoretical frame of reference. The result showed that there is a great understanding of risk and active work against different types of risks, and to minimize disruptions, the main measure is communication with suppliers. The study also revealed that there is no uniform risk strategy and risk management among the individuals in the purchasing department, instead the risks are managed based on individual situations.
26

Essays on Supply Chain Disruptions: A Schema, Managerial Reactions, and Decision-Making

Polyviou, Mikaella 28 December 2016 (has links)
No description available.
27

Fanfiction: A Look into the Disruptions of Gender Identity through Tropes

Preslar, Stephanie 01 May 2021 (has links)
Fanfiction provides the unique opportunity to explore disruptions of heteronormativity through tropes. By exploring different fanfictions in the Soulmate AU, ABO Dynamics, and Mpreg tropes, the disruptions indicate a desire to explore gender, identity, and sexuality through queered characters. Male slash fanfiction provides the chance to examine the disruption of the heteronormative through the queering of male characters and placing them into situations that may embrace the feminine or a female-gendered experience. The situating of heterosexual male characters into queered roles allows an examination of how this disrupts canonical ideas of gender, identity, and sexuality. By reviewing the male slash relationships in these tropes, the narratives may explain why the disruption of heteronormativity seems so appealing to fanfiction authors and readers. Heteronormativity restricts exploration of new dynamics and experiences that fanfiction authors and readers may crave to investigate. Disrupting that heteronormativity presents new opportunities for experiences in areas that may receive underrepresentation.
28

The impact of pharmaceutical supply chain disruptions on buyers’ behavior, medication errors, and market share

Park, Minje 24 August 2022 (has links)
This dissertation investigates the consequences of supply chain disruptions in pharmaceutical supply chains. Across different studies, I examine various impacts of pharmaceutical supply chain disruptions on buyer’s behavior, medication errors, and market share. In Chapter 1, coauthored with Anita Carson, Erin Fox, and Rena Conti, we demonstrate the stockpiling behaviors of buyers during the early phase of the COVID-19 pandemic. Leveraging a quasi-experimental design on IQVIA’s National Sales Perspectives™ data, we show that the sales volume of essential medicines related to U.S. hospital-based COVID-19 treatment concentrated only for the first two months of the pandemic. After these two months, the sales volume of drugs for COVID-19 treatment decreases significantly despite a nationwide increase in COVID-19-related hospitalizations. In Chapter 2, coauthored with Anita Carson and Rena Conti, we examine the impact of a hurricane that decimated the factories of major producers of heparin, an important drug used frequently in hospitals. Using a natural experiment, we find that the hurricane-related pharmaceutical supply chain disruption increased medication error rates of heparin. In addition, we find significant spillover effects. The supply chain disruption increased the medication error rates of a substitute drug. In Chapter 3, coauthored with Anita Carson and Rena Conti, we study how long it takes to recover the market share after the supply chain disruptions using a new metric we propose, Time to Recover Market Share. We explore the differential effects by the brand type of products, the competition level in markets, and the duration of the supply disruptions. With the extensive global supply chain disruptions that we are facing today, understanding their potential consequences is significant. This dissertation advances our understanding of the different impacts of supply chain disruptions and provides practical implications for supply chain members to build resilient supply chains and minimize the effects of supply chain disruptions.
29

An AIS-Based Approach for Measuring Waterway Resiliency: A Case Study of Houston Ship Channel

Zohoori, Sepideh, Jafari Kang, Masood, Hamidi, Maryam, Maihami, Reza 01 January 2022 (has links)
Resiliency measurement is a great tool for evaluating system performance and proposing solutions to prevent damage and to recover from disruptive events. This study proposes an analytic approach to quantify narrow waterway systems’ resiliency during disasters. First, metrics are introduced to quantify the resiliency before, during, and after a disruption. The existing Key Performance Indicators (KPIs) for Maritime Transportation Systems (MTS) are examined, and two metrics, 1) the number of inbound and outbound vessels and 2) Total Stopped Vessel-Hours, are selected to measure the resiliency of a waterway system. Second, a heuristic method is developed to derive the KPIs from the Automatic Identification System (AIS) data. Finally, the proposed methodology is performed for the Houston Ship Channel (HSC) AIS data before, during, and after Hurricane Harvey, in August 2017. The results are presented for the entire channel and highlight useful information about the performance of individual docks, terminals, and waterway zones within HSC. This study helps decision-makers identify the weaknesses and potential bottlenecks in a waterway confronting a disruption and come up with remedies.
30

Connections: interventions to promote socialization and engagement among people with dementia

Ham, Pola 06 June 2017 (has links)
Behavioral disruptions are highly prevalent, affecting almost all persons with dementia at some point during the course of their illness (McConnell, 2014). These behavioral disruptions in persons with dementia are commonly associated with decreased quality of life in the person exhibiting the symptoms as well as their caregivers (Fauth, Zarit, Hofer & Stephens, 2006). The purpose of this doctoral project was to design an intervention to promote socialization and engagement among people with dementia. A review of evidence-based interventions was conducted to identify effective non-pharmacological interventions to decrease behavioral disruptions in persons with dementia. The most promising interventions for reducing symptoms of behavioral disruptions in persons with dementia identified in the literature include music therapy, animal-assisted therapy, massage, activities-based interventions, behavioral management and combination therapies incorporating two or more of these interventions. Incorporating these effective interventions, a new program, Connections, was developed. The program includes a series of different daily interventions to be provided in a skilled nursing facility over the course of six weeks for residents with mild to moderate dementia. The Connections program is guided by a person-centered care philosophy and utilizes an evidence-based approach. Connections is designed to address the unmet psychological needs in people with dementia, such as fear or a sense of loss of control, lack of meaningful activities, loneliness and a lack of social interaction and decrease the behavioral disruptions.

Page generated in 0.0636 seconds