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  • 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.
521

Structuring Emperical Methods for Reuse and Efficiency in Product Development Processes

Bare, Marshall Edwin 21 December 2006 (has links) (PDF)
Product development requires that engineers have the ability to predict product performance. When product performance involves complex physics and natural phenomena, mathematical models are often insufficient to provide accurate predictions. Engineering companies compensate for this deficiency by testing prototypes to obtain empirical data that can be used in place of predictive models. The purpose of this work is to provide techniques and methods for efficient use of empirical methods in product development processes. Empirical methods involve the design and creation of prototype hardware and the testing of that hardware in controlled environments. Empirical methods represent a complete product development sub-cycle within the overall product development process. Empirical product development cycles can be expensive in both time and resources. Global economic pressures have caused companies to focus on improving the productivity of their product development cycles. A variety of techniques for improving the productivity of product development processes have been developed. These methods focus on structuring process steps and product artifacts for reuse and efficiency. However these methods have, to this point, largely ignored the product development sub-cycle of empirical design. The same techniques used on the overall product development processes can and should be applied to the empirical product development sub-cycle. This thesis focuses on applying methods of efficient and reusable product development processes on the empirical development sub-cycle. It also identifies how to efficiently link the empirical product development sub-cycle into the overall product development process. Specifically, empirical product development sub-cycles can be characterized by their purposes into three specific types: first, obtaining data for predictive model coefficients, boundary conditions and driving functions; second, validating an existing predictive model; and third, to provide the basis for predictions using interpolation and extrapolation of the empirical data when a predictive model does not exist. These three types of sub-cycles are structured as reusable processes in a standard form that can be used generally in product development. The roles of these three types of sub-cycles in the overall product development process are also established and the linkages defined. Finally, the techniques and methods provided for improving the efficiency of empirical methods in product development processes are demonstrated in a form that shows their benefits.
522

Observational Studies of Software Engineering Using Data from Software Repositories

Delorey, Daniel Pierce 06 March 2007 (has links) (PDF)
Data for empirical studies of software engineering can be difficult to obtain. Extrapolations from small controlled experiments to large development environments are tenuous and observation tends to change the behavior of the subjects. In this thesis we propose the use of data gathered from software repositories in observational studies of software engineering. We present tools we have developed to extract data from CVS repositories and the SourceForge Research Archive. We use these tools to gather data from 9,999 Open Source projects. By analyzing these data we are able to provide insights into the structure of Open Source projects. For example, we find that the vast majority of the projects studied have never had more than three contributors and that the vast majority of authors studied have never contributed to more than one project. However, there are projects that have had up to 120 contributors in a single year and authors who have contributed to more than 20 projects which raises interesting questions about team dynamics in the Open Source community. We also use these data to empirically test the belief that productivity is constant in terms of lines of code per programmer per year regardless of the programming language used. We find that yearly programmer productivity is not constant across programming languages, but rather that developers using higher level languages tend to write fewer lines of code per year than those using lower level languages.
523

Field Evaluation of Asphalt Overlays on State Route 30 in Northern Utah

Butler, Mark J. 14 April 2010 (has links) (PDF)
The purpose of this research was to compare the rutting, cracking, and development of roughness of two asphalt overlay types commonly used in northern Utah and to evaluate how well the Mechanistic-Empirical Pavement Design Guide (MEPDG) can predict the observed results. AC-10 and PG 64-34 asphalt overlay materials were paved in a checkerboard pattern at a test site on State Route 30 near Logan, Utah, and observed for 3 years at 6-month intervals. Primary data included rutting, cracking, and roughness. At the conclusion of the 3-year evaluation period, rut depths were 0.08 in. deeper, on average, in the AC-10 overlay compared to the PG 64-34 overlay. Fatigue cracking in the PG 64-34 overlay exceeded that in the AC-10 overlay by 0.11 percent, on average. The measured roughness of the PG 64-34 overlay was greater by 24 in./mile, on average, than the AC-10 overlay. In summary, although the AC-10 product exhibited more rutting than the PG 64-34 product, the latter exhibited more fatigue cracking and greater roughness than the former. Although the MEPDG predictions for rutting are within the range of observed rut depths, the MEPDG overestimated the AC-10 rut depth while underestimating the PG 64-34 rut depth. Furthermore, the apparent inability of the MEPDG to predict amounts of longitudinal, fatigue, and transverse cracking comparable to measured values is concerning; the MEPDG predicted negligible cracking for both overlay types for the duration of the 3-year analysis period. While the MEPDG cracking models appear to be unsuitable for predicting cracking at this site, the MEPDG predictions for roughness are shown to be within the range of observed values. Given the findings of this study, the researchers recommend that Utah Department of Transportation (UDOT) engineers consider specifying the AC-10 asphalt overlay product for pavement treatments in conditions similar to those evaluated in this investigation. Even though the MEPDG predictions of rutting and roughness were generally correct, the researchers recommend that such predicted values be used as general predictions only. Further evaluation of these models, as well as the MEPDG models for longitudinal, fatigue, and transverse cracking, should be completed before the MEPDG is fully adopted by UDOT.
524

A descriptive qualitative empirical study describing how basic hand hygiene is conducted in Lesotho as well as the healthcare staffs’ thoughts on it

Wolle, Darren, Isacson, Evelina January 2023 (has links)
Background: Hand hygiene is now, more than ever, one of the most important factors to minimize spread of infection. In low income countries like Lesotho between 6% - 19% of patients contract at least one healthcare associated infection. Compared to between 3% - 10% in high income countries. Objective: The aim was to describe how healthcare professionals experience and conduct basic hand hygiene procedures at a hospital in Lesotho. Method: The study was conducted using a qualitative content analysis with a manifest level of abstraction and an inductive approach. Result: The results showed in our final categories; Healthcare professionals perceive different views on the risk for contamination, Healthcare professionals described hand hygiene as important although there are hindrances, and Healthcare professionals stated that basic hand hygiene need support from management for good compliance. That healthcare professionals did not always perform basic hand hygiene the way it was supposed as low budget or lack of knowledge was an obstacle. Conclusions: There are many problem areas, such as cost, availability and knowledge although the personnel are interested, resourceful and willing to make the best of any situation they come across.
525

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.
526

Experimental analysis of thermal mixing at reactor conditions

Bergagio, Mattia January 2016 (has links)
High-cycle thermal fatigue arising from turbulent mixing of non-isothermal flows is a key issue associated with the life management and extension of nuclear power plants. The induced thermal loads and damage are not fully understood yet. With the aim of acquiring extensive data sets for the validation of codes modeling thermal mixing at reactor conditions, thermocouples recorded temperature time series at the inner surface of a vertical annular volume where turbulent mixing occurred. There, a stream at either 333 K or 423 K flowed upwards and mixed with two streams at 549 K. Pressure was set at 72E5 Pa. The annular volume was formed between two coaxial stainless-steel tubes. Since the thermocouples could only cover limited areas of the mixing region, the inner tube to which they were soldered was lifted, lowered, and rotated around its axis, to extend the measurement region both axially and azimuthally. Trends, which stemmed from the variation of the experimental boundary conditions over time, were subtracted from the inner-surface temperature time series collected. An estimator assessing intensity and inhomogeneity of the mixing process in the annulus was also computed. In addition, a frequency analysis of the detrended inner-surface temperature time series was performed. In the cases examined, frequencies between 0.03 Hz and 0.10 Hz were detected in the subregion where mixing inhomogeneity peaked. The uncertainty affecting such measurements was then estimated. Furthermore, a preliminary assessment of the radial heat flux at the inner surface was conducted. / <p>QC 20161116</p>
527

A case study research on Scrum Framework

Zikopi, Eleni January 2019 (has links)
Agile methods have been widely implemented in the industry while teaching these methods is a substantial part of Computer Science and Engineering program curricula. Evidencedriven data of agile practices, methods, and tools have been extracted based on empirical studies with students, however, there is an important need for more anecdotal evidence to confirm these findings. In order to fill this gap, this paper explores the perceptions and the applicability of the Scrum Framework in a student research team in an industrial context. Empirical data have been gathered through interviews with the case study participants combined with a survey. The analysis reveals that student experiences are mainly positive and that they can easily grasp the benefits of Scrum Framework. The challenges of implementing Scrum in such a setting mainly concern the balance between coach and self-organization, formulating accurate user stories when researching, finding the most suitable estimation method, as well as planning when conducting research. The empirical findings may potentially be extrapolated in student scrum teams or even in industrial settings. Finally, this research paper should encourage other researchers to investigate the adoption of Scrum in a student setting. / Agila metoder har implementerats i stor utsträckning inom branschen, medan undervisning i dessa metoder är en väsentlig del av utbildningarna för datavetenskap och teknik. Bevisdriven data om agila arbetssätt, metoder och verktyg har tagits fram från empiriska studier med studenter, men det finns ett viktigt behov av mer anekdotiska bevis för att bekräfta dessa resultat. För att fylla detta gap utforskar den här rapporten uppfattningarna och tillämpligheten av ramverket Scrum i ett studentforskningsteam i ett industriellt sammanhang. Empiriska data har samlats genom intervjuer med deltagarna i fallstudien i kombination med ett frågeformulär. Analysen visar att studentupplevelserna är främst positiva och att man lätt kan förstå fördelarna med Scrum. Utmaningarna med att implementera Scrum i en sådan miljö gäller främst balansen mellan coaching och självorganiserande, formulera exakta användarhistorier när man forskar, finner den mest lämpliga uppskattningsmetoden samt planerar forskningsrelaterat arbete. De empiriska fynden kan eventuellt extrapoleras i Scrumteam med studenter eller till och med i industriella miljöer. Slutligen bör detta forskningsarbete uppmuntra andra forskare att undersöka införandet av Scrum i ett studentkontext.
528

Hänvisning av akutsökande patient med Triagehandboken som beslutstöd - sjuksköterskans upplevelser

Gleerup, Lena, Jensen, Marie January 2009 (has links)
Den första process som möter den akutsökande patienten på en akutmottagning är triaget, vars syfte är att bedöma patientens medicinska tillstånd. Att hänvisa en akutsökande patient till annan vårdnivå är ett komplext beslut, som ska fattas med kunskap, erfarenhet och med respekt för den enskilda patienten. Syftet med studien var att beskriva sjuksköterskornas upplevelse i hänvisningssituationen av akutsökande patienter, med Triagehandboken som beslutstöd. Metoden var kvalitativ med semistrukturerade intervjuer. Åtta sjuksköterskor på en akutmottagning i södra Sverige inkluderades i studien. Data materialet bearbetades och analyserades med inspiration av kvalitativ innehållsanalys där fem huvudkategorier framstod. Resultatet visade att sjuksköterskorna upplevde att hänvisningen av patienter till annan vårdnivå som ett stort ansvar och bemötandet av patienter har stor betydelse. Uppföljningen av patienten och introduktionen ansågs som bristande. Triagehandboken upplevdes som ett stöd i beslutfattandet. Sjuksköterskorna ansåg att det saknades vissa symtom och åkommor i Triagehandboken, men att bristen kompenserades med egen eller kollegers kunskap. / The first process that meets the acute patient applicants on an emergency department is the triage, whose purpose is to assess the patient’s medical condition. To refer a patient to other care is a complex decision to be taken with knowledge, experience and respect for the individual patient. The purpose of the study was to describe nurses´ experiences of referring patients on an emergency department in the reception desk with the Triage manual as a decision support. The method was qualitative with semistructured interviews. Eight nurses on an emergency department in southern of Sweden were included in the study. The data material was processed and analyzed with the inspiration of qualitative content analysis in which five main categories emerged. The result showed that the nurses experienced reference of patients to other care is a major responsibility and treatment of patients is of great importance. The followup of the patient and the introduction was considered inadequate. Triage manual perceived as aid in decision making. The nurses felt an absence of certain symptoms and disorders in the Triage Manual, but that shortage was compensated by their own or colleagues´ knowledge.
529

Effect Of Source Water Blending On Copper Release In Pipe Distribution System: Thermodynamic And Empirical Models

Xiao, Weizhong 01 January 2004 (has links)
This dissertation focuses on copper release in drinking water. Qualitative and quantitative assessment of Cu and Fe corrosion by process water quality was assessed over one year in a field study using finished waters produced from seven different treatment process and eighteen pilot distribution systems (PDSs) that were made from unlined cast iron and galvanized steel pipes, and lined cement and PVC pipes taken from actual distribution systems. Totally seven different waters were studied, which consisted of three source waters: groundwater, surface, and simulated brackish water designated as G1, S1, and RO. With certain pre-established blending ratios, these three waters were blended to form another three waters designated as G2, G3, and G4. Enhanced surface water treatment was CFS, ozonation and GAC filtration, which was designated as S1. The CFS surface water was nanofiltered, which is S2. All seven finished waters were stabilized and chloraminated before entering the PDSs. Corrosion potential was compared qualitatively and quantitatively for all seven waters by monitoring copper and iron release from the PDSs. This dissertation consists of four major parts. (1) Copper corrosion surface characterization in which the solid corrosion products formed in certain period of exposure to drinking water were tried to be identified with kinds of surface techniques. Surface characterization indicated that major corrosion products consists of cuprite (Cu2O) as major underneath corrosion layer and tenorite (CuO), cupric hydroxide (Cu(OH)2) on the top surface. In terms of dissolution/precipitation mechanism controlling the copper concentration in bulk solution, cupric hydroxide thermodynamic model was developed. (2) Theoretical thermodynamic models were developed to predict the copper release level quantitatively based on controlling solid phases identified in part (1). These models are compared to actual data and relative assessment is made of controlling solid phases. (3) Non-linear and linear regression models were developed that accommodated the release to total copper for varying water quality. These models were verified using independent data and provide proactive means of assessing and controlling copper release in a varying water quality environment. (4) Simulation of total copper release was conducted using all possible combinations of water quality produced by blending finished waters from ground, surface and saline sources, which involves the comparison of copper corrosion potentials among reverse osmosis, nanofiltration, enhanced coagulation, lime softening, and conventional drinking water treatment.
530

Safety Improvements On Multilane Arterials A Before And After Evaluation Using The Empirical Bayes Method

Devarasetty, Prem Chand 01 January 2009 (has links)
This study examines the safety effects of the improvements made on multi-lane arterials. The improvements were divided into two categories 1) corridor level improvements, and 2) intersection improvements. Empirical Bayes method, which is one of the most accepted approaches for conducting before-after evaluations, has been used to assess the safety effects of the improvement projects. Safety effects are estimated not only in terms of all crashes but also rear-end (most common type) as well as severe crashes (crashes involving incapacitating and/or fatal injuries) and also angle crashes for intersection improvements. The Safety Performance Functions (SPFs) used in this study are negative binomial crash frequency estimation models that use the information on ADT, length of the segments, speed limit, and number of lanes for corridors. And for intersections the explanatory variables used are ADT, number of lanes, speed limit on major road, and number of lanes on the minor road. GENMOD procedure in SAS was used to develop the SPFs. Corridor SPFs are segregated by crash groups (all, rear-end, and severe), length of the segments being evaluated, and land use (urban, suburban and rural). The results of the analysis show that the resulting changes in safety following corridor level improvements vary widely. Although the safety effect of projects involving the same type of improvement varied, the overall effectiveness of each of the corridor level improvements were found to be positive in terms of reduction in crashes of each crash type considered (total, severe, and rear-end) except for resurfacing projects where the total number of crashes slightly increased after the roadway section is resurfaced. Evaluating additional improvements carried out with resurfacing activities showed that all (other than sidewalk improvements for total crashes) of them consistently led to improvements in safety of multilane arterial sections. It leads to the inference that it may be a good idea to take up additional improvements if it is cost effective to do them along with resurfacing. It was also found that the addition of turning lanes (left and/or right) and paving shoulders were two improvements associated with a project�s relative performance in terms of reduction in rear-end crashes. No improvements were found to be associated with a resurfacing project�s relative performance in terms of changes in (i.e., reducing) severe crashes. For intersection improvements also the individual results of each project varied widely. Except for adding turn lane(s) all other improvements showed a positive impact on safety in terms of reducing the number of crashes for all the crash types (total, severe, angle, and rear-end) considered. Indicating that the design guidelines for this work type have to be revisited and safety aspect has to be considered while implementing them. In all it can be concluded that FDOT is doing a good job in selecting the sites for treatment and it is very successful in improving the safety of the sections being treated although the main objective(s) of the treatments are not necessarily safety related.

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