• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 47
  • 21
  • 6
  • 2
  • Tagged with
  • 77
  • 77
  • 22
  • 20
  • 17
  • 13
  • 12
  • 11
  • 10
  • 10
  • 10
  • 9
  • 9
  • 9
  • 9
  • 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

Distance Measurements Using Ultra Wideband

Hossain, Md. Iqbal January 2012 (has links)
Ultra wideband (UWB) is vastly under consideration of research industry that promises high data rata, low power consumption and economic solution. UWB was in use of military since 1950’s. In 2002 Federal communication commission (FCC) approved the use of 3.1-10.6 GHz band for unlicensed UWB applications. UWB is a suitable choice for sensing and position objects because of high bandwidth and fine time resolution. The goal of this work is to explore the UWB technology in context of distance measurement between two nodes. We have described the characterization; reliability and ranging precision of an impulse UWB based transceiver for both indoor and outdoor environments. This thesis discuss in detail about UWB technology. Chapter 1 discusses about UWB applications, regulation and bandwidth properties. Chapter 2 and 3 discuss about single band and multi band modulation and detection techniques. Chapter 4 gives a complete description how to measure position through ranging and positioning parameters. Finally, to estimate the ranging and positioning, a two way ranging algorithm based on TOA employed as part of this work is described in detail in chapter 5. A theoretical analysis of impulse UWB radio for wireless communication and ranging is provided employing the Shannon Hartley theorem and Cramer-Rao lower bound (CRLB) method.
2

Fault Diagnosis in Distributed Simulation Systems over Wide Area Networks using Active Probing / Feldiagnostik i Distibuerade Simulationssystem över Wide Area Networks med Active Probing

Andersson, Filip January 2016 (has links)
The domain of distributed simulation is growing rapidly. This growth leads to larger and more complex supporting network architectures with high requirements on availability and reliability. For this purpose, efficient fault-monitoring is required. This work is an attempt to evaluate the viability of an Active probing approach in a distributed simulation system in a wide area network setting. In addition, some effort was directed towards building the probing-software with future extensions in mind. The Active probing approach was implemented and tested against certain performance requirements in a simulated environment. It was concluded that the approach is viable for detecting the health of the network components. However, additional research is required to draw a conclusion about the viability in more complicated scenarios that depend on more than the responsiveness of the nodes. The extensibility of the implemented software was evaluated with the QMOOD-metric and not deemed particularly extensible.
3

New generation ironing board for compact living / Nya generationens strykbräda för compact living

Lang, Johanna January 2016 (has links)
This report describes the product development thesis that was conducted as an end project in the Master programme Industrial Design at Jönköping University. The thesis has been about developing, designing and building an ironing board for compact living. The name for the product that has been developed is UNI and it is a multifunctional ironing board which can either be mounted on the wall or hanged over the door. When the ironing board is not in used, it can be folded up and will then act as a mirror. When the ironing board is folded down, parts of the mirrors frame will be folded down and act like a supporting leg for the ironing board. On the inside is shelves and hooks mounted. Here can the owner store small things like keys and jewelleries. To get the best final result, have the design process Bootcamp Bootleg been used. This design process is divided in to five different stages where different methods are used to help with moving the project forward. The CAD-programme SolidWorks 2014 was used to create the CAD-models and the renderings where made in the rendering programme Keyshot 5. The physical model which was made during this thesis, was made in a scale of 1:1. The materials that were used for the model were hard foam, metal, wood, acrylic mirror, wadding and fabric. This thesis has been performed in collaboration with the company Rörets Industrier AB located in Jönköping, Sweden. / Denna rapport beskriver examensarbete inom produktutveckling som gjordes som det slutliga projektet på Master programmet Industrial Design på Jönköpings universitet. Detta examensarbete har handlat om att utveckla, formge och bygga en strykbräda för compact living. Namnet på den produkt som blivit utvecklad är UNI och det är en multifunktionell strykbräda som kan monteras på en vägg eller hängas över en dörr. När strykbrädan inte används, kan den fällas upp och användas som en spegel. När strykbrädan är nedfälld kommer delar av spegels ram att fällas ner och fungera som ett stöttande ben. På insidan finns de hyllor och krokar monterat. Här kan ägaren förvara små föremål som nycklar eller smycken. För att få ett så bra resultat som möjligt, har design processen Bootcamp Bootleg använts. Denna process är uppdelad i fem olika steg där man använder olika metoder för att föra projektet framåt. CAD-programmet SolidWorks 2014 har använts för att skapa CAD-modellerna och renderingarna har gjorts i renderingsprogrammet Keyshot 5. Den fysiska modellen som gjorts under examensarbete, har gjorts i skala 1:1. Materialen som använts i vid bygget av modellen var hårt skum, metall, trä, spegelglas och tyg. Detta examensarbete har gjorts i samarbete med företaget Rörets Industrier AB lokaliserat i Jönköping, Sverige
4

COLLISION AVOIDANCE FOR AUTOMATED VEHICLES USING OCCUPANCY GRID MAP AND BELIEF THEORY

Reza Soltani (11178675) 06 August 2021 (has links)
This thesis discusses occupancy grid map, collision avoidance system and belief theory, and propose some of the latest and the most effective method such as predictive occupancy grid map, risk evaluation model and OGM role in the belief function theory with the approach of decision uncertainty according to the environment perception with the degree of belief in the driving command acceptability. Finally, how the proposed models mitigate or prevent the occurrence of the collision.
5

Innovation in Traditionally Monopolistic Firms - A Telco Case Study

Umair, Syed Muhammad January 2012 (has links)
The telecom industry is moving from a stable environment to a very dynamic industry where the entrance of new players and the macro economic factors like crisis have been pushing it towards commoditization. In spite of the fact that the Telco consumer base is increasing the value generation capability of this industry has been challenged in the past years. The management is well aware of the situation but due to the traditionally monopolistic nature of these organizations finds it difficult to push any radical change. The purpose of the study is to identifying those factors which contributed to the success of these firms in past and later identifying those elements which are needed for these organizations to foster an innovative culture capable of bringing the needed changes. The major objectives of the research include identifying the main reason behind the need for innovation today and factors that have been hindering the innovation process in these firms. The next step was to study the best practices outside the Telcos industry which have helped other firms to be the Innovation leaders. Finally the study identifies those strategies and best practices which are viable in the Telecom industry. It has been found that the size and political nature of these organizations makes it difficult to push ideas to reality. Therefore the first need is the need of a culture change and a separate path (apart from the traditional line management) for the escalation of ideas. Secondly the Telco industry is not able to keep pace with the innovation of its complementing industries and therefore there is a dire need make innovation a priority from exploring new revenue sources to the innovation of business models with its existing partners. In the past the industry has tried the industrial silos model by decentralizing and given complete autonomy to its major revenue generating services but now it needs to demolish these departmental silos and be open to provide services which cut across many of its existing services without thinking too much about cannibalization.
6

Scoop optimization : A preliminary study

Artola, Bixente January 2019 (has links)
Scoops are important parts in an aircraft engine design, as they provide airflowto different equipment and subsystems. The optimization of such a component isessential in order to find a design that can perform properly within a range of flightconditions, with a minimum impair of main flow aerodynamic performances. Scoopdesign methods are generally based on previous experimental results and are usuallyconstrained by the limited space available. The studied configuration concerns theflush scoop located inside the secondary flow of turbofans which provides flow fora turbine cooling equipment. Depending on flight conditions and engine workingpoint, this scoop will experience various flow regimes, from low mass flow rates tochoke flows. Therefore, the study of several scooped mass flow rates is mandatoryto extract the scoop behaviour. The thesis concerns the preliminary step beforea 3D CFD optimization : a study of influence is run on the baseline geometry inorder to investigate the robustness of the solution computed using different methodsand to determine the parameters to be optimized. Firstly, the full post-processingmethodology is defined to properly evaluate the performance of a design (scoopefficiency, induced pressure losses). A second step consists in analysing the abilityof CFD solvers to capture the different flow behaviour. This point is addressed bycomparing solvers (Fluent, elsA, PowerFLOW), meshes (structured, unstructured)and turbulence models. The third step deals with the optimization strategy definitionto improve the scoop design and thus the engine fuel consumption.
7

Implementation of an automated,personalized model of the cardiovascularsystem using 4D Flow MRI

Almquist, Camilla January 2019 (has links)
A personalized cardiovascular lumped parameter model of the left-sided heart and thesystemic circulation has been developed by the cardiovascular medicine research groupat Linköping University. It provides information about hemodynamics, some of whichcould otherwise only have been retrieved by invasive measurements. The framework forpersonalizing the model is made using 4D Flow MRI data, containing volumes describinganatomy and velocities in three directions. Thus far, the inputs to this model have beengenerated manually for each subject. This is a slow and tedious process, unpractical touse clinically, and unfeasible for many subjects.This project aims to develop a tool to calculate the inputs and run the model for mul-tiple subjects in an automatic way. It has its basis in 4D Flow MRI data sets segmentedto identify the locations of left atrium (LA), left ventricle (LV), and aorta, along with thecorresponding structures on the right side.The process of making this tool started by calculation of the inputs. Planes were placedin the relevant positions, at the mitral valve, aortic valve (AV) and in the ascending aortaupstream the brachiocephalic branches, and flow rates were calculated through them. TheAV plane was used to calculate effective orifice area of AV and aortic cross-sectional area,while the LV end systolic and end diastolic volumes were extracted form the segmentation.The tool was evaluated by comparison with manually created inputs and outputs,using 9 healthy volunteers and one patient deemed to have normal left ventricular func-tion. The patient was chosen from a subject group diagnosed with chronic ischemic heartdisease, and/or a history of angina, together with fulfillment of the high risk score ofcardiovascular diseases of the European Society of Cardiology. This data was evaluatedusing coefficient of variation, Bland-Altman plots and sum squared error. The tool wasalso evaluated visually on some subjects with pathologies of interest.This project shows that it is possible to calculate inputs fully automatically fromsegmented 4D Flow MRI and run the cardiovascular avatar in an automatic way, withoutuser interaction. The method developed seems to be in good to moderate agreement withthose obtained manually, and could be the basis for further development of the model.
8

Design and Analysis of an All-optical Free-space Communication Link

Levander, Fredrik, Sakari, Per January 2002 (has links)
Free Space Optics (FSO) has received a great deal of attention lately both in the military and civilian information society due to its potentially high capacity, rapid deployment, portability and high security from deception and jamming. The main issue is that severe weather can have a detrimental impact on the performance, which may result in an inadequate availability. This report contains a feasibility study for an all-optical free-space link intended for short-range communication (200-500 m). Laboratory tests have been performed to evaluate the link design. Field tests were made to investigate availability and error performance under the influence of different weather conditions. Atmospheric impact due to turbulence related effects have been studied in detail. The most crucial part of the link design turned out to be the receiver optics and several design solutions were investigated. The main advantage of an all-optical design, compared to commercially available electrooptical FSO-systems, is the potentially lower cost.
9

MSC Adams modelling of mechanical system in A400M Crew Entrance Door

Lindberg, David January 2012 (has links)
Saab Aerostructures has developed the Crew Entrance Door (CED) for Airbus A400M. Airbus has decided some different load cases for which the Crew Entrance Door must be built to withstand without something breaking down. The door is maneuvered by a mechanical system and the load cases are essential for the sizing of the components in the mechanical system. Saab has previously used MS Excel to analytically calculate resulting forces in the mechanical system due to external and/or internal loads in the different load cases. This report describes how the mechanical system for A400M Crew Entrance Door instead can be modeled and solved numerically with the computer program MSC Adams/View. Creating a model of a mechanical system in MSC Adams/View proved to be easy and fairly quick. The benefit of working with MSC Adams instead of MS Excel is that it is quicker and more user friendly. The major differences when comparing results were believed to be an effect of comparing results from a kinematic model with results from a dynamic model. Therefore it is in the Authors opinion that the analytical method to calculate resulting forces with MS Excel can be replaced by numerical calculations with MSC Adams/View. However, apart from calculating reaction forces there are additional post-simulation calculations for which it is perhaps more beneficial to use MS Excel. To do these post-simulation calculations in MS Excel it is easy to use exported results from MSC Adams. If Saab Aerostructures decide to start working with MSC Adams/View and if Saab wants geometry to be imported to the model, then an advise from the Author is to have a software installed which can convert step-files (*.stp or *.step) to the MSC Adams preferred file format Parasolid (*.xmt_txt or *.x_t). The software should also be able to repair geometry which will greatly increase mass accuracy.
10

VTOL UAV - A Concept Study

Moëll, Daniel, Nordin, Joachim January 2008 (has links)
This thesis deals with the development of a Conceptual Design Tool for unmanned helicopters, so called VTOL UAVs. The goal of the Design Tool is: • Quick results • Good accuracy • Easy to use The two first points of the goal are actually more or less dependent on each other. In almost all cases a high accuracy gives a slow calculator and vice versa. In order to fulfill the goal a compromise between calculation accuracy and calculation time needs to be done. To make the Design Tool an easy to use program a graphical user interface is used. The graphical user interface allows the user to systematically work his way thru the program from a fictive mission to a complete design of a helicopter. The pre-requirements on the user have been eliminated to a minimum, but for the advanced user the possibilities to create more specific and complex helicopters are good. In order to develop a Conceptual Design Tool the entire helicopter needs to be seen as a complete system. To see the helicopter as a system all of the sub parts of a helicopter need to be studied. The sub parts will be compared against each other and some will be higher prioritized than other. The outline of this thesis is that it is possible to make a user friendly Conceptual Design Tool for VTOL UAVs. The design procedure in the Design Tool is relatively simple and the time from start to a complete concept is relatively short. It will also be shown that the calculation results have a good agreement with real world flight test data.

Page generated in 0.0711 seconds