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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.
21

Using Telemetry to Measure Equipment Mission Life on the NASA Orion Spacecraft for Increasing Astronaut Safety

Losik, Len 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The surprise failure of two NASA Space Shuttles and the premature failures of satellite subsystem equipment on NASA satellites are motivating NASA to adopt an engineering discipline specifically developed for preventing surprise equipment failures. The NASA Orion spacecraft is an Apollo module-like capsule planned to replace the NASA Space Shuttle reusable launch vehicle for getting astronauts to space and return to the earth safely as well as a crew escape vehicle stored at the ISS. To do so, NASA is adopting a non-Markov reliability paradigm for measuring equipment life based on the prognostic and health management program on the Air Force F-35 Joint Strike Fighter. The decision is based on the results from the prognostic analysis completed on the Space Shuttle Challenger and Columbia that identified the information that was present but was ignored for a variety of reasons prior to both accidents. The goal of a PHM is to produce equipment that will not fail prematurely and includes using predictive algorithms to measure equipment usable life. Equipment with transient behavior, missed by engineering analysis is caused from accelerated of parts will fail prematurely with 100% certainty. With the processing speed of today's processors, transient behavior is caused from at least one part suffering from accelerated aging. Transient behavior is illustrated in equipment telemetry in a prognostic analysis but not in an engineering analysis. Telemetry is equipment performance information and equipment performance has been used to increase reliability, but performance is unrelated to equipment remaining usable life and so equipment should be failing prematurely. A PHM requires equipment telemetry for analysis and so analog telemetry will be available from all Orion avionics equipment. Replacing equipment with a measured remaining usable life of less than one year will stop the premature and surprise equipment failures from occurring during future manned and unmanned space missions.
22

Statistické vyhodnocení nepřetržitosti dodávky elektrické energie v zadané části distribuční sítě / Statistical evaluation of distribution supply continuity in given part of distribution network

Milka, Jiří January 2013 (has links)
The thesis is focused on the statistical analysis of the continuity of power distribution in a specified part of the distribution network. Its aim is to explain the basic concepts and calculations in reliability distribution of electrical energy, which is an essential element for improving the quality of electricity supplied to end customers. The work is divided into two parts (theoretical part and a practical part), which are further divided into chapters and subchapters according to individual areas of focus. In the introduction the explains the aim and content of the of chapters work. You are also given a specific issue and its explanation. The conclusion summarizes the results of the practical part. The work is supplemented by annexes a list of images, tables, symbols and abbreviations that are used for better clarity and orientation.
23

Beräkningsmall för vindlast enligt Eurokoder samt jämförelsestudie av  vindlastberäkningsmetoder / Calculation model for wind load according to Eurocodes and a comparative study of calculation methods for wind load

Wesslund, Lovisa January 2012 (has links)
Detta examensarbete har genomförts i samarbete med byggteknikavdelning på Ramböll Sverige AB, i Norrköping/Linköping. På företaget finns ett behov av att förenkla arbetet med vindlastberäkningar för hallbyggnader enligt Eurokoden. Idag använder företaget en förenklad metod som överdimensionerar. För att kunna göra en mer exakt beräkning helt enligt Eurokoden och effektivisera arbetet har det i detta examensarbete skapats en beräkningsmall för detta ändamål. Beräkningsmallen har tagits fram i programmet Microsoft Excel. För att också kunna se konsekvenserna av att jobba med en förenklad metod, har det utförts en jämförelsestudie mellan två befintliga projekt på företaget. Resultatet av jämförelsestudien visar på vad som är anledningen till skillnaden mellan det förenklade sättet, metod 1 och det mer exakta, metod 2. Rapporten innehåller en studie kring de faktorer som används vid beräkning av vindlast. Detta har gjorts för att kunna se vilken av faktorerna som bidrar till störst skillnad i resultat mellan de båda metoderna. Som grund till allt detta, innehåller rapporten också en teoretiskt bakgrund till hur vindlast ska dimensioneras enligt Eurokoden. Detta utgör första delen av rapporten. / This study has been performed in a collaboration with the company Ramböll Sweden AB in Norrköping/Linköping. At the company there is a need to simplify calculations concerning the wind load on industrial buildings according to the Eurocode. Today the company uses a simplify method which result in an over-dimension. To make a more exact method in accordance to the Eurocode and increase the efficiency at the work, it has in this study created a calculation model for this purpose. The calculation model has been created in the program Microsoft Excel. To be able to see the consequences to work with a simplified method, it has been done a comparison study between two current project at the company. The results of the comparison study show the reason to the difference between the simplified method, method 1 and the more exact method, method 2. The report containing  a study of the factors that uses in the calculations. This has been done to see which of the factors that contributes to the largest difference in result between the both methods. As the basis for all this, the report also contains a theoretical background about how the wind load should be dimensioned according to the Eurocode. This is the first part of this report.
24

Ombyggnation och klimatpåverkan : En kvalitativ studie om utmaningar och möjligheter

Burman, Alexander, Laigar, Joel January 2024 (has links)
Inom den svenska bygg- och fastighetsbranschen har frågan om klimatpåverkan och hållbarhet blivit alltmer central. Branschens påverkan på miljön, särskilt i form av koldioxidutsläpp, är väl dokumenterad och utgör en betydande del av Sveriges totala utsläpp av växthusgaser. Trots den historiska påverkan har branschen visat framgång genom att minska växthusgas- och kväveoxidutsläppen de senaste åren. Minskningarna kan relateras till att branschens aktörer har vidtagit åtgärder för att utveckla mer hållbara byggtekniker samtidigt som intresset för återbruk och återvinning ökat. En av de åtgärderna som genomförts för att minska branschens klimatpåverkan är införandet av klimatdeklarationskravet, vilket innebär att den klimatpåverkan som uppstår under uppförandet av en byggnad måste redovisas för alla nybyggnationer. För närvarande omfattas dock inte ombyggnationer av klimatdeklarationskravet. Vilket har medfört att ombyggnationers klimatpåverkan inte är lika utforskad som nybyggnationers klimatpåverkan. Syftet med denna studie är att utreda hur branschens aktörer kan främja klimatarbete vid ombyggnationer av kommersiella fastigheter under byggskedet. Detta genom att kartlägga hur aktörernas nuvarande klimatarbete ser ut vid ombyggnationer, identifiera arbetssätt och material med betydande klimatpåverkan samt vilka utmaningar och möjligheter ett ökat klimatarbete medför. För att besvara studiens forskningsfrågor har en litteratur- och en intervjustudie genomförts. Litteraturstudiens första del ger en bakgrund till ombyggnationer gällande definition, motiv och process. Den andra delen handlar om byggbranschens klimatpåverkan och vilka drivkrafter som finns för att minska den i form av klimatåtgärder, klimatdeklarationer och beräkningsverktyg. Avslutningsvis beaktas klimatarbete vid ombyggnationer utifrån en ekonomisk synpunkt. Den erhållna kunskapen från litteraturstudien låg sedan i grund till intervjustudien som bestod av semistrukturerade intervjuer med tio respondenter med chefsbefattningar inom byggbranschen Resultatet från datainsamlingen visar att klimatarbetet vid ombyggnationer varierar mellan aktörerna. Aktörerna som kommit längre i sitt klimatarbete har lyckats integrera det i sina arbetsprocesser genom exempelvis användning av eget framtagna beräkningsverktyg där koldioxidutsläpp kan jämföras mot pris. I dagsläget ligger det största fokuset för att minska klimatpåverkan på att öka återanvändningen av befintligt byggmaterial. I studien framkom det att främst glas, textilmattor och undertaksplattor är material som prioriteras att sparas och återbrukas. Kombinationen av att de alla är vanligt förekommande, lätta att demontera och återmontera samt att de har en betydande klimatbelastning är de främsta anledningarna. I takt med att medvetenheten om klimatförändringarna ökar, tar bygg- och fastighetsbranschen allt större hänsyn till klimataspekten. Detta skapar incitament för att branschens aktörer vill ligga i framkant och därigenom kunna skapa en affärsmöjlighet genom att kunna påvisa att de kan genomföra ombyggnationer utan stora utsläpp av koldioxidekvivalenter. Det uppstår spänningar mellan befintliga funktionskrav enligt nybyggnadskrav på fastigheter och klimatmål vid större renoveringar, exempelvis när äldre byggelement inte möter nuvarande standarder för tillgänglighet, ljudisolering eller takhöjd. Studien betonar vikten av förstärkt samarbete inom bygg- och fastighetsbranschen för att hantera dessa utmaningar och främja klimatarbete. Genom att utbyta expertis och erfarenheter kan aktörerna gemensamt utveckla strategier för att minska koldioxidekvivalentutsläpp vid renoveringar och förbereda sig för framtida utsläppskrav. / Within the Swedish construction and real estate industry, the issue of climate impact and sustainability has become increasingly important. The industry’s historical impact on the environment, particularly in the form of carbon dioxide emissions, constituted a significant portion of Sweden's total greenhouse gas emissions. In the last couple of years, construction and real estate companies have been making progress in reducing greenhouse gas and nitrogen oxide emissions. These reductions can be attributed to industry actors taking measures to develop more sustainable construction techniques while also increasing interest in reuse and recycling. One of the measures implemented to reduce the industry's climate impact is the introduction of the climate declaration requirement. This means that the climate impact arising during the construction of a building must be reported for all new constructions. The introduction of climate declaration is a step in the right direction, but it is not covering renovation projects. This has resulted in the climate impact of renovations not being as explored as the climate impact of new constructions. The purpose of this study is to investigate how industry actors can promote climate action in the renovation of commercial properties during the construction phase. This will be achieved by mapping out the current climate action of industry actors in renovations, identifying methods and materials with significant climate impacts, and exploring the challenges and opportunities associated with increased climate action. To answer the study's research questions, both a literature review and interviews have been conducted. The first part of the literature review provides background on renovations regarding definitions, motivations, and processes. The second part of the literature review focuses on the construction industry's climate impact and the driving forces for reducing it, such as climate measures, climate declarations, and calculation tools. In the last part of the literature review climate action in renovations are considered from an economic standpoint. The gained literature knowledge was put into practice through semi-structured interviews with ten respondents who are fulfilling management positions in the construction industry. The results from this study show that climate action in renovations varies among industry actors. Those who have made more progress in their climate action have successfully integrated it into their working processes, for example, by using internally developed calculation tools where carbon dioxide emissions can be compared against cost. Currently, the key to reducing climate impact lies in increasing the reuse of existing building materials. The study found that primarily glass, textile carpets, and ceiling tiles are materials prioritized for preservation and reuse. These are all commonly used, easy to dismantle and reassemble, and have a significant impact on the climate.  Tensions arise between existing functional requirements according to new building regulations and climate goals in major renovations when reusing existing material. Think for example about older building elements which do not meet current standards for accessibility, sound insulation, or ceiling height. This research overall emphasizes the importance of enhanced collaboration within the construction and real estate industry to address these challenges and promote climate action. By exchanging expertise and experiences, industry actors can collectively develop strategies to reduce carbon dioxide equivalent emissions in renovations and prepare for future emission requirements.
25

Results from the Prognostic Analysis Completed on the NASA EUVE Satellite to Measure Equipment Mission Life

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper addresses the research conducted at U.C. Berkeley Space Sciences Laboratory, Center for Extreme Ultra Violet Astrophysics between 1994 and 1995 on the NASA EUVE ion-orbit satellite. It includes the results from conducting a scientific analysis called a prognostic analysis completed on all satellite subsystem equipment. A prognostic analysis uses equipment analog telemetry to measure equipment remaining usable life. The analysis relates equipment transient behavior, often referred to as "cannot duplicates" in a variety of industries caused from accelerated aging to the equipment end-of-life with certainty. The analysis was confirmed by using proprietary, pattern recognition software by Lockheed Martin personnel Lockheed Martin personnel completed an exploration into the application of statistical pattern recognition methods to identify the behavior caused from accelerated aging that experts in probability reliability analysis claims cannot exist. Both visual and statistical methods were successful in detecting suspect accelerated aging and this behavior was related to equipment end of life with certainty. The long-term objective of this research was to confirm that satellite subsystem equipment failures could be predicted so that satellite subsystem and payload engineering personnel could be allocated for only the time that equipment failures were predicted to occur, lowering the cost of mission operations. This research concluded that satellite subsystem equipment remaining usable life could be measured and equipment failures could be predicted with certainty so that engineering support for mission operations could be greatly reduced.
26

Computation and Simulation of the Effect of Microstructures on Material Properties

Carter, W. Craig 01 1900 (has links)
Methods for and computed results of including the physics and spatial attributes of microstructures are presented for a number of materials applications in devices. The research in our group includes applications of computation of macroscopic response of material microstructures, the development of methods for calculating microstructural evolution, and the morphological stability of structures. In this review, research highlights are presented for particular methods for computing the response in: 1) ferroelectric materials for actuator devices; 2) coarse-graining of atomistic data for simulations of microstructural evolution during processing; 3) periodic and non-periodic photonic composites; and 4) re-chargeable battery microstructures. / Singapore-MIT Alliance (SMA)
27

Návrh aplikace pro online prodej zájezdů / Application Design for The Online Sale of Tours

Kintr, Lukáš January 2014 (has links)
The main topic of this diploma thesis is the complete design of the web application for booking and selling package tours and other related services offered by the travel agency. The first part of this thesis describes the theory basis for the proposition, creation (production) and the implementation of the web applications with the emphasis on the methodology and technology used in this diploma thesis. The second part of the thesis consists of an analysis of current state in the travel agency and this analysis is the foundation of the last part of this thesis which contains the design of the design web application.
28

Att återkoppla eller inte återkoppla, det är frågan! : Matematikbokens förmedling av tidigare kunskaper med fokus på skriftliga beräkningsmetoder

Skår Lunneland, Katharina January 2021 (has links)
Bakgrund: Vi är nu för tiden vana vid att använda oss av digitala hjälpmedel vid matematiska beräkningar. Detta tycks ha trängt undan behovet av standardalgoritmerna och andra skriftliga beräkningsmetoder. Är det så att dessa traditionella beräkningsmetoder har gått ur tiden? Kan digitala hjälpmedel ersätta alla delar som dessa metoder har bidragit till om vi ser till utvecklandet av matematisk förståelse? Min uppfattning är att det inte är så, utan att algoritmer och andra skriftliga beräkningsmetoder fortfarande har en viktig roll att spela i elevers utveckling av den matematiska förståelsen.  Syfte: Att undersöka hur man presenterar och återkopplar till skriftliga beräkningsmetoder och standardalgoritmer i matematikböcker från förskoleklass till gymnasiet. Metod: Studien är konstruerad utifrån en läroboksanalys där både en kvalitativ och en kvantitativ undersökning gjorts för att inringa både de övergripande strukturer som funnits i materialet, samt för att kunna se mer svåråtkomliga inslag, överlappningar och brister i det analyserade materialet. Tidigare forskning och litteratur inom området har beskrivits och löpande analyserats för att ge en bild av vad som sticker ut respektive överlappar åsikts- och resultatmässigt i de valda studierna och texterna. Resultat: Studien visar på en brist i matematikböckernas återkoppling till tidigare kunskaper. De kunskaper som främst är i fokus är de som rör standardalgoritmer och andra skriftliga beräkningsmetoder, men liknande brister går att se även inom andra matematiska områden. Bristen på återkoppling förekommer i merparten av de analyserade matematikböckerna och ger ett intryck av att fokus har förskjutits från algoritmkunskap till att eleven skall arbeta med digitala hjälpmedel. Det blir dock tydligt att även denna kunskap, om digitala hjälpmedel, inte heller prioriteras högt. Detta kan man se genom att beskrivningar av användning av digitala hjälpmedel förekommer mycket sparsamt i de analyserade matematikböckerna. Slutsats:Slutsatsen som kan dras av denna studie är att de analyserade matematikböckerna saknar den röda tråd som fås genom återkoppling och som skulle behövas för att ge bättre förutsättningar att skapa god matematisk förståelse. / Background: Nowadays digital tools, like calculators, are what we mainly use in our mathematical calculations. This has, seemingly, pushed away our need for other methods of calculation. We appear not to be in need of standard algorithms and other written calculating processes. Does this mean that these calculating processes are a thing of the past? Can digitals tools replace all parts contributed by the traditional methods from the perspective of development ofmathematical understanding? My point of view is that this is not the case. Instead, I believe that these “out of time” methods are highly important in the development of mathematical understanding. Purpose: To examine the way books of mathematics from first year of school all the way through the Swedish gymnasium courses, presents and reconnect to knowledge of written calculating methods and standard algorithms. Method: This study is constructed through an analysis of books of mathematics where both a qualitative and a quantitative part are included to cover both the overall structures of knowledge mediation in the analysed books and to find the more subtle elements, like knowledge overlaps or knowledge faults in the analysed books. Prior research and literature on the subject have been described and continuously analysed with the purpose to find opinions that stands out and also to find overlapping opinions or results, when comparing the chosen studies and texts. Result: The study points to a lack of reconnection to earlier knowledge in the analysed books. Foremost this concerns knowledge of standard algorithms and other types of written calculating methods, but a similar lack of reconnection is also seen within other areas of mathematics in the analysed books. The lack of reconnection occurs in most of the analysed books which gives an impression of focus being shifted from knowledge of algorithms and other written calculating methods to the advantage of digital tools. It does, however, also become clear that knowledge of how to use digital tools is equally not prioritized, since such information is sparsely presented in the analysed books. Conclusion: The conclusion that can be drawn from this study is that the analysed books of mathematicslack the common thread of knowledge that we get from reconnecting to earlier knowledge, and which would be needed to give better chances to create good mathematical understanding.
29

Techniky paralelního zpracování výpočtů / Techniques for parallel computing

Vodák, René January 2014 (has links)
The text of this thesis deals with techniques of parallel processing calculations. It is an analysis of the most important libraries for parallelization including libraries for parallelization on GPU graphics cards and computing speed by comparing these libraries in Visual Studio 2010 based on a simple application searching primes on three different computer hardware configurations. With OpenCL library, that achieved the best result, there are formed two applications – an improved program for searching prime numbers using the sieve of Eratosthenes and a program for calculating the integral with the trapezoidal rule.
30

Zesilování stavebních konstrukcí / Reinforcement of structures

Janda, Miloslav January 2012 (has links)
The subject of the diplom thesis is strengthening of building structures. The thesis is focused on strengthening of reinforced concrete compression of rod structures with concrete cover. The thesis consists of three parts. The first one is theoretical treatise on strengthening not only concrete compression of rod structures. The second part describes creating computer program of calculating concrete rod element rectangular overview which is made stronger with concrete cover using method of limit transformation. The third part consists of the static calculation strengthening of the concrete column rectangular overview with using concrete strengthening cover.

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