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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.
1

Usage of digital twin in order to predict temperature within a thermic test rig / Användning av digital tvilling för att förutspå temperatur i en termisk testrig

Blomqvist, Malinda January 2022 (has links)
Many people suffer from diabetes and as a result of the disease, circulatory issues in feet are common. To find such issues at an early stage, Vistafeet were developing a product that measures the temperature in feet. This product needed to be calibrated and for that purpose, this master thesis was evaluating a proposed calibration rig and the possibility of using a digital twin in order to predict the temperature of the rig. The concept of a digital twin includes a physical product, a virtual model of the same product, and information flow between them. By receiving information from the physical product, the digital model should be able to estimate or predict information about the physical product, information that is then used to improve the physical product. In order to be a true digital twin, it should be automatic and in real time. If the data flow is delayed, a better description is digital shadow or digital model, depending on the level of connection. Due to time limitations during this master thesis, the real time connection required for a proper digital twin was not achieved. The scope was then limited from a digital twin to a digital model. The evaluation of the rig was conducted through a case study of the rig including a number of tests, with the purpose of replicating and verifying the result from a previous study by Xiao and Fan [23]. The digital model was made by logging data from the physical product to later use within the simulated environment. First the digital model was compared and adjusted to the information from several thermal points of the physical model. The thermal points were spread out to give as much information as possible the de simulation, but only placed on sides of the rig that would have easy access if the rig were to be used for calibration. Once the digital model was adjusted, the final simulation was made, and temperature data was compared in verification points to see how well the digital model fit the physical model. The verification points were chosen on the calibrating side of the rig and spread out to see if the model managed to predict potentially tricky places. To finalize the investigation of the rig, errors within the model and the rig itself were evaluated. The result showed that it was possible to fulfill the conclusions from a previously made study. The digital model turned out to be accurate and managed to predict the temperature down to ± 0,1 degrees for most verification points. However, one verification point close to a heater element had much less accuracy than the rest. The result was still acceptable, but this indicates that it is not possible to assume that the model can predict entirely correct temperature within the whole rig only because some points are correct. Especially if trying to predict temperature in more difficult places such as close to a heater. The investigation of errors within the digital model showed that the digital model simulated well within the limits as the temperature range and the controller changed. The sensor close to the heater remained in the same error range as in the first simulation. The errors in hardware were evaluated and the variation between sensors was measured to about 0,1 degrees. However, there might also be a slight offset from the true temperature due to errors affecting all thermistors equally. Even though a 0,1 resolution between sensors is quite good, it is insufficient resolution for this test since the errors in the tests were about ± 0,1 degrees. Despite that, the error of the simulation was still in an acceptable range for a digital model setup. For further improvement, a proper real time digital twin could be implemented, but also higher resolution sensors are required. / Många människor lider av diabetes och som ett resultat av denna sjukdom är cirkulations problem i fötter vanligt. För att på ett tidigt stadie upptäcka sådan problem utvecklade Vista feet en produkt som mäter temperaturen i fötterna för att upptäcka cirkulationsproblem. För att produkten ska fungera måste sensorerna i den kalibreras. I detta examensarbete görs en utvärdering av ett förslag på en kalibreringsrigg. Även möjligheten att använda en digital tvilling för att förutspå temperaturen kommer utvärderas. En digital tvilling inkluderar en fysisk produkt, and virtuell modell av samma produkt samt informationsflöde mellen dem. Genom att få information från den fysiska produkten ska den digitala modellen kunna uppskatta eller förutse information om den fysiska produkten, information som används för att förbättra den fysiska produkten. För att vara en äkta digital tvilling ska informationsflödet ske automatiskt och i realtid. Om informationsflödet sker i efterhand, är en bättre beskrivning en digital skugga eller en digital modell, beroende på nivån av automation och fördröjning. På grund av tidsbegränsning i examensarbetet var det inte möjligt att göra en realtidsuppkopplad digital tvilling, och omfattningen av arbetet begränsades till en digital modell. Utvärderingen av riggen gjordes i form av en fallstudie innehållande ett antal test och genom en replikering av en tidigare gjord studie av Xiao och Fan [23]. Den digital modellen gjordes genom att data från den fysiska produkten sparades och sedan användes för att genomföra den digitala simuleringen. Den digital modellen and passades sedan efter informationen i ett antal ”termiska” punkter (thermal points). Dessa punkter var utspridda för att ge så mycket information som möjligt, men enbart placerade på sidor som lätt kan nås om riggen skulle användas för kalibrering. När modellen var anpassad gjordes en sista simulering. Då jämfördes temperaturen i ett antal verifieringspunkter (verification points) för att se om modellen lyckades förutspå temperaturen i dess punkter. Verifieringspunkterna var på kalibreringssidan av riggen, utspridda för att se om modellen klarade att förutspå även potentiellt svåra platser. Slutligen undersöktes även felkällor i modellen och i riggen. Resultatet av studien visade att det var möjligt att uppfylla slutsatserna från den replikerade rapporten. Den digitala modellen blev mycket noggrann och lyckades förutse temperaturen med en noggrannhet på ± 0,1 grad för de flesta punkterna. Det var dock tydligt att det simulerade värdet i en punkt nära ett element hade betydligt sämre noggrannhet än resten av punkterna. Det var fortfarande en godkänd noggrannhet, men den stora variationen från övriga punkter tyder på att bara för att resultatet stämmer bra i vissa punkter så stämmer det nödvändigtvis inte lika bra i alla punkter. Speciellt om det är en punkt som avviker från övriga och därmed är svårare att uppskatta, som i detta fall, nära ett element. Undersökningen av fel i den digitala modellen visade att den stämde fortsatt bra även när temperaturen och kontrollsystemet ändrades, även om noggrannheten på sensorn nära värmaren var fortsatt låg, var det på ungefär samma nivå. I hårdvaran uppmättes skillnaden i temperatur som termistorerna mätte till 0,1 grad. Dock är det sannolikt ett lite större konstant fel då hårdvaru felen ofta påverkar alla termistorer lika. En noggrannhet mellan sensorerna på 0,1 grad är bra, men inte tillräckligt när felet mellan den simulerade modellen och mätta temperaturen är ± 0,1. Trots det är felet inom gränsen för vad som är acceptabelt för en digital modell. För att förbättra arbetet skulle in riktig realtidsuppkopplad tvilling kunna implementeras, men det krävs också att sensorerna har högre upplösning.
2

Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM

Elmubarak, Mona Dr. January 2018 (has links)
Magister Scientiae Dentium - MSc(Dent) / BACKGROUND: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. AIM: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. METHOD: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). RESULTS: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). CONCLUSION: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
3

Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM

Elmubarak, Mona January 2018 (has links)
>Magister Scientiae - MSc / Background: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. Aim: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. Method: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). Results: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). Conclusion: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
4

Cenová analýza zakázky a vyhotovení DMT / Price analysis and preparation of contract DMT

BULINOVÁ, Markéta January 2013 (has links)
The topic of this thesis is the "contract price analysis and the preparation of DMT." Its aim is to contract pricing. Price analysis, contract relates complete focus and copy planimetric and altimetry plan and DMT, from initial reconnaissance of the terrain to its transmission investor. Price contract and a copy planimetric and altimetry plan and DMT was carried out according to price list of which this contract deal from the beginning. It is a small company Geoplan Plzeň. Orientation and copy of the order was dealt with in my work. Its aim was to prepare a digital terrain model (3D model) and making a contour plan of the area. The processing of geodetic survey work has been of interest locations electronic tacheometry.
5

CHALLENGES AND OPPORTUNITIES WHEN DEVELOPING A DIGITAL MODEL OF A PROCESS

Lindblad, Amanda January 2022 (has links)
BACKGROUND - The development of Industry 4.0 increases the opportunities to both automate and digitize processes in the manufacturing industry. The steel industry has been around for many years, which means firmly anchored operations and both manual- and automated processes. To make better decisions, identify bottlenecks, and test new functions without having to stop the production, a digital model of the process can be helpful. Furthermore, with the rapid development of technology, digital models can be further developed into digital twins. A digital twin should be able to handle the communication between the physical- and digital world automatically and analyze data to make decisions in the process. RESEARCH QUESTIONS What are the challenges of developing a digital model representing a production line within a global steel manufacturing company? What opportunities could a digital model of a production line entail, and how could Industry 4.0 technologies create opportunities to further develop the digital model into a digital twin? METHODS - In this project, both a literature- and case study have been carried out. During the literature study, techniques that can be used to develop the digital model further have been investigated. During the case study, a digital model of a Quench Line was developed to gather practical experience of what it can mean to create a digital model of a manufacturing process within a steel manufacturing company. The model has been developed in MATLAB/Simulink. RESULTS - The most significant challenges when developing digital flow simulation models identified in this project were data management/access, handling variations, verifying the model, andlack of knowledge linked to digital models in general. The opportunities identified and confirmed in this project were that the model could be used to carry out new logistics planning, bottleneck analyses, and test new machine implementations. To further develop the digital model into a digital twin, Industry 4.0 technologies will be crucial. The technologies that will be useful are the Internet of Things, Artificial Intelligence, Machine Learning, Cloud Computing, and Big Data.
6

Využití metody fotogrammetrie při pasportizaci památkové budovy / Using the Photogrammetry Method for a Historic Building Passportization

Ondová, Natálie January 2019 (has links)
This thesis deals with the assessment of the building technical condition of the monument building of the South Gate of the Veveří Castle. The use of photogrammetry – as one of the main methods of measurement – is a 3D model of this object and its passportization. Based on written materials and a closer survey of the object, this overview is considered a problem that should serve as a means of redress.
7

Potential of demand response for chlor-alkali electrolysis processes

Lerch, Philipp, Scheller, Fabian, Bruckner, Thomas 13 October 2023 (has links)
Chlor-alkali electrolysis indicates significant demand response potential, accounting for over 2% of Germany’s total elec-tricity demand. To fully analyze this potential, digital models or digital twins are necessary. In this study, we use the IRPopt modeling framework to develop a digital model of an electrolysis process and examine the cost-optimal load shifting application in the day-ahead spot and balancing reserve market for various price scenarios (2019, 2030, 2040). We also investigate the associated CO2 emissions. Combined optimization at both markets results in greater and more robust cost savings of 16.1% but cannibalizes the savings that are possible through optimization separately at each market. In future scenarios, the shares of savings from spot and reserve market could potentially reverse. CO2 savings between 2.5% and 9.2% appear only through optimization at the spot market and could even turn negative if optimized solely at the reserve market.
8

Orthodontic diagnostics and measurements on digital study models made with an intraoral scanner

Konakovic, Damir January 2013 (has links)
Introduktion:Modellanalys har traditionellt gjorts på fysiska gipsmodeller. Idag finns ny teknik som möjliggör framställning av digitala modeller utan behov av konventionella avtryck. Syftet med den här studien är att undersöka tillförlitligheten hos digitala modeller framställda med en intraoral scanner, patientupplevelsen och olika tidsaspekter förenade med tekniken.Metod:På ett urval av 20 vuxna personer gjordes både konventionell avtryckstagning och en intraoral scanning (TRIOS, 3Shape) av bettet för framställning av gipsmodeller och digitala modeller. Den kliniska tidsåtgången mättes och personerna besvarade ett frågeformulär gällande sin upplevelse av metoderna. Fyra observatörer diagnostiserade bettrelationer och utförde ortodontiska mätningar på gipsmodeller med ett skjutmått och digitala modeller med OrthoAnalyzer Orthodontics (3Shape, Danmark). Tidsåtgången mättes för digital- respektive konventionell modellanalys. Statistiska analyser gjordes utifrån Paired samples t test, korstabeller och frekvensanalys.Resultat:Diagnostik av horisontella-, vertikala- och transversella bettrelationer på digitala modeller har hög tillförlitlighet. Få statistiskt signifikanta skillnader fanns för linjära mätningar på digitala modeller jämfört med gipsmodeller. För majoriteten av observatörerna tog digital modellanalys längre tid än konventionell modellanalys. Likaså var den kliniska tidsåtgången för intraoral scanning signifikant längre än för konventionell avtryckstagning och metoden prioriterades lägre av försökspersonerna.Konklusion:Digitala modeller framställda med en intraoral scanner är en tillförlitlig metod för ortodontisk diagnostik och terapiplanering. Tekniken har en rad fördelar och förbättras ständigt men dess acceptans för den enskilde klinikern blir i slutändan en kostnadsfråga. / Introduction:Model analysis has traditionally been carried out on physical plaster models. New technology allows the production of digital models without the need for conventional impressions. The purpose of this study was to evaluate the validity of digital models made with an intraoral scanner, patient experience and different time aspects associated with this technology.Methods:A sample of 20 adults was selected. Plaster models and digital models were obtained from conventional impressions and an intraoral scanning (TRIOS, 3Shape) respectively. The clinical time required for impression taking and intraoral scanning was recorded and the subjects were asked to answer a questionnaire regarding their experience of both methods. Four independent examiners diagnosed malocclusions and performed measurements with a digital caliper on plaster models and by using OrthoAnalyzer Orthodontics (3Shape, Denmark) for digital models. Time required for digital- and conventional model analysis respectively, was recorded. Statistical analysis was performed by using Paired samples t test, crosstabs and frequency analysis.Results:Diagnostics of horizontal-, vertical- and transversal malocclusions with digital models showed high validity. Few statistically significant differences were found for measurements made on digital models compared to direct measurements on plaster models. For a majority of the examiners, digital model analysis was more time consuming than conventional model analysis. Also, clinical time required for intraoral scanning was significantly greater than for conventional impression taking. The subjects preferred conventional impression taking.Conclusions:Digital models made with an intraoral scanner are a reliable method for orthodontic diagnostics and treatment planning. The technique has a number of advantages and is constantly improving but its acceptance depends ultimately on the cost-effectiveness ratio to the individual practitioner.
9

THE NEXT GENERATION OF TELEMETERING REQUIREMENTS FOR THE AIR FORCE SEEK EAGLE PROGRAM

Dyess, William W. Jr, Shirley, Benjamin M., Robinson, Wiley J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Air Force SEEK EAGLE Office (AFSEO) was chartered by the Secretary of the Air Force in December 1987. The mission of the AFSEO is to provide the United States Air Force increased combat capability through central management of the aircraft-stores certification process and provide in-house engineering and operations research capabilities. Additionally, the AFSEO is required to ensure the future viability of the aircraft-stores organic in-house capability with the insertion of evolving technologies. To accomplish this mission, the AFSEO employs all phases of the test process; from Digital Model and Simulation (DMS) to Open Air Range (OAR) flight tests. The AFSEO desires to prepare for the future DoD environment, and minimize the cost of developing its products that require advanced sensors and telemetry capability. For a number of years, a mainstay in the process has been instrumented aircraft. These aircraft were specially instrumented to support the mission of AFSEO. Similarly, stores were instrumented to obtain environmental data such as loads and vibration. With the rising cost of instrumentation and the national DoD trend to reduce the cost of development and maintenance of instrumentation, a new method will need to be found. Several advanced concepts in ground and airborne instrumentation at Eglin AFB are needed to support the mission of the AFSEO. These include a new generation of telemetry devices, sensors, and data acquisition components to provide rapid and cost effective instrumentation of test aircraft, stores, and suspension equipment. The new generation telemetry will provide integrated circuitry with “peel and stick” subminiature telemetry sensors. These telemetry sensors will provide flutter and structural loads data for aircraft-stores combinations. In conjunction with the telemetry sensors, advanced aircraft platform instrumentation will be needed to match precision flight mechanics to the spatial telemetry measurements for stress, strain, and dynamic activity of stores.
10

Avaliação dos arcos dentários com e sem fissuras labiopalatinas em crianças de 3 a 9 meses / Evaluation of dental arches with and without cleft lip and palate in children aged 3 to 9 months

Fernandes, Viviane Mendes 18 February 2013 (has links)
O propósito deste trabalho foi mensurar as dimensões dos arcos dentários de crianças com fissuras labiopalatinas, de 3 a 9 meses, antes das cirurgias primárias, e comparar com crianças sem fissura labiopalatina. A amostra foi composta de 223 crianças, divididas em grupos: sem deformidades craniofaciais (G1), fissura pré-forame incompleta (G2), fissura pré-forame completa (G3), fissura transforame unilateral (G4) e fissura transforame bilateral (5). Para avaliação, os arcos dentários superiores das crianças foram moldados com silicona de condensação. Os modelos passaram por um processo de digitalização, por meio de escâner 3D e as medidas utilizadas para a correlação entre os grupos foram realizadas diretamente nas imagens escaneadas. Nas imagens, foram determinados pontos de referência, necessários para a realização das medidas de avaliação. Os resultados mostraram diferença estatisticamente significativa na distância intercaninos (DIC) entre G1-G4 (p= 0,000), G1-G5 (p= 0,007), G2-G4 (p= 0,000), G2-G5 (p= 0,000), e G3-G4 (p= 0,008). Para distância intertuberosidades (DIT) foram encontradas diferenças estatisticamente significativas entre: G1-G4 (p= 0,000), G1-G5 (p= 0,000), G2-G4 (p= 0,000), G2-G5 (p= 0,000), G3-G4 (p= 0,009) e G3-G5 (p= 0,000). Para amplitude anterior da fissura unilateral (AAFuni), o G3 apresentou diferença estatisticamente significativa com relação ao G4 (p= 0,000) e para amplitude anterior da fissura esquerda (AAFe) e direita (AAFd) com relação ao G5 (p= 0,011 e p= 0,030). Para amplitude posterior da fissura (APF), houve diferença estatisticamente significativa entre G4 e G5 (p= 0,013). Com base nos resultados obtidos, foi possível constatar que as crianças com fissura labiopalatina apresentaram dimensões transversais dos arcos dentários maiores que as crianças sem fissura labiopalatina, de 3 a 9 meses, antes das cirurgias primárias. A DIC foi maior nas crianças com fissura transforame unilateral e a DIT foi maior nas crianças com fissura transforame bilateral em relação aos grupos estudados. Houve aumento significante da AAF e APF nos diferentes tipos de fissura com relação à severidade da fissura de lábio e/ou palato. / The purpose of this study was to measure the dimensions of the dental arches of 3-9 month children with cleft lip and palate, before the primary surgery, and compared them with children without cleft lip and palate. The sample consisted of 223 children, divided into groups: without craniofacial deformities (G1), unilateral cleft lip (G2), unilateral cleft lip and alveolus (G3), unilateral cleft lip and palate (G4) and bilateral cleft lip and palate (5). For evaluation, impressions of the upper dental arches of the children were performed with condensation silicone. The casts underwent a process of scanning through 3D scanner and the measurements used for the correlation among groups were executed directly on the scanned images. On the images, the landmarks required to perform the evaluation measurements were determined. The results showed statistically significant differences in intercanine distance (ICD) between G1 - G4 (p = 0.000), G1 - G5 (p = 0.007), G2 - G4 (p = 0.000), G2 - G5 (p = 0.000), and G3 - G4 (p = 0.008). For the posterior arch width (PAW), the following statistically significant differences were found: between G1 - G4 (p = 0.000), G1 - G5 (p = 0.000), G2 - G4 (p = 0.000), G2 - G5 (p = 0.000), G3 - G4 (p = 0.009), and G3 - G5 (p = 0.000). The unilateral anterior cleft width (UACW) exhibited statistically significant differences between G3 and G4 (p = 0.000); the left (LACW) and right anterior cleft width (RACW) showed differences between G3 and G5 (p = 0.011 and p = 0.030). For posterior cleft width (PCW), statistically significant differences between G4 and G5 (p = 0.013) were found. Based on these results, it was found that 3-9 month cleft lip and palate children had transverse dimensions of the dental arches higher than those without cleft lip and palate, before the primary surgeries. The ICD was higher in children with unilateral cleft lip and palate and PAW was higher in children with bilateral cleft lip and palate among the groups studied. A significant increase in the ACW and PCW of the different cleft types with respect to the severity of cleft lip and / or palate was found.

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