• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 59
  • 15
  • 9
  • 8
  • 6
  • 5
  • 4
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 121
  • 32
  • 20
  • 20
  • 18
  • 18
  • 17
  • 15
  • 14
  • 14
  • 13
  • 12
  • 12
  • 12
  • 11
  • 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.
31

Jämförelse av NoSQL-databas och SQL-baserad relationsdatabas : En förklarande studie för när NoSQL kan vara att föredra framför en relationsdatabas / Comparison of NoSQL database and SQL relational database

Hedman, Jennifer, Holmberg, Mikael January 2019 (has links)
With the explosive development of the mobile world, web applications and Big Data, new requirements for storage capacity and speed of database systems have arisen. The traditional relational database that has long dominated the marked has received competition because of its lack in speed and scalability. NoSQL is a collective name for databases that are not based on the traditional relational model. NoSQL databases are designed to easily expand their storage capacity while delivering high performance. NoSQL databases have been around for decades but the need for them is relatively new. Our partner expressed a desire to know what differences exist between NoSQL and the traditional relational database. To clarify these differences, we have answered the following questions in this work:  When can a NoSQL database be preferred to a relational database?  What are the differences in database performance? In order to answer these questions, a literature study has been conducted together with experiments where we test which performance differences exist between the selected databases. Performance tests have been performed with the benchmarking tool Yahoo Cloud Serving Benchmark, to verify or falsify the enhanced performance of the NoSQL databases. The hypotheses were falsified in both NoSQL databases. The results showed that the relational database performed better than the cloud based NoSQL databases, but also that the relational database performance deteriorates when the load increased. The results of the experiments are combined with the literature study and together answer our questions. The conclusion is that no database performs better than another one, it is the requirements of the data to be stored. From these requirements, analyses can be made to draw conclusions about what kind of database is preferable.
32

Hard Realtime Rapid Prototyping Development Platform / Utvecklingsplattform för snabb framtagning av prototyper för hård realtidsexekvering

Rosenquist, Christer January 2003 (has links)
<p>Matlab Simulink is a commonly used tool in the design process of control systems. To further take advantage of the Matlab Simulink models it is desirable to translate them for realtime use together with the possibility to read/write physical signals. </p><p>Real-Time Workshop is an extension to Simulink that automatically generates code from a model to a variety of target platforms. RTAI and RTLinux are hard realtime operating systems, making use of Linux. </p><p>To make automatically generated code run on RTAI and RTLinux an adaptation of the generation of code is necessary. </p><p>To control, for example, an automotive engine a data acquisition card with an appropriate device driver is required. Comedi, an open source project, provides a number of device drivers for data acquisition cards. </p><p>The developed system makes use of Simulink, Real-Time Workshop, RTAI or RTLinux, and the standard data acquisition card NI 6035E using a Comedi device driver. The Simulink models may be executed at frequencies up to 50 kHz on ordinary PC hardware. </p><p>The evaluation of the system consisted of measuring the interrupt latency of the used motherboard's bus, measuring computation times running Simulink models with known complexity, running models developed at Vehicular Systems and a comparison of interfacing Simulink/Real-Time Workshop between RTAI and RTLinux. </p><p>The recommended realtime operating system is RTAI due to the open source community support of it as a target platform for Real-Time Workshop.</p>
33

Real-time Transmission Over Internet

Gao, Qi January 2004 (has links)
<p>With the Internet expansion, real-time transmission over Internet is becoming a new promising application. Successful real-time communication over IP networks requires reasonably reliable, low delay, low loss date transport. Since Internet is a non-synchronous packet switching network, high load and lack of guarantees on data delivery make real-time communication such as Voice and Video over IP a challenging application to become realistic on the Internet. </p><p>This thesis work is composed of two parts within real-time voice and video communication: network simulation and measurement on the real Internet. In the network simulation, I investigate the requirement for the network"overprovisioning"in order to reach certain quality-of-service. In the experiments on the real Internet, I simulate real-time transmission with UDP packets along two different traffic routes and analyze the quality-of- service I get in each case. </p><p>The overall contribution of this work is: To create scenarios to understand the concept of overprovisioning and how it affects the quality-of-service. To develop a mechanism to measure the quality-of-service for real-time traffic provided by the current best-effort network.</p>
34

New Interface for Rapid Feedback Control on ABB-Robots

Lundqvist, Rasmus, Söreling, Tobias January 2005 (has links)
<p>Automation in manufacturing has come far by using industrial robots. However, industrial robots require tremendous efforts in static calibration due to their lack of senses. Force and vision are the most useful sensing capabilities for a robot system operating in an unknown or uncalibrated environment [4]and by integrating sensors in real-time with industrial robot controllers, dynamic processes need far less calibration which leads to reduced lead time. By using robot systems which are more dynamic and can perform complex tasks with simple instructions, the production efficiency will rise and hence also the profit for companies using them. </p><p>Although much research has been presented within the research community, current industrial robot systems have very limited support for external sensor feedback, and the state-of-the-art robots today have generally no feedback loop that can handle external force- or position controlled feedback. Where it exists, feedback at the rate of 10 Hz is considered to berare and is far from real-time control. </p><p>A new system where the feedback control can be possible within a real-time behavior, developed at Lund Institute of Technology, has been implemented and deployed at Linköping Institute of Technology. </p><p>The new system for rapid feedback control is a highly complex system, possible to install in existing robot cells, and enables real-time (250 Hz) sensor feedback to the robot controller. However, the system is not yet fully developed, and a lot of issues need to be considered before it can reach the market in other than specific applications. </p><p>The implementation and deployment of the new interface at LiTH shows that the potential for this system is large, since it makes production with robots exceedingly flexible and dynamic, and the fact that the system works with real- time feedback makes industrial robots more useful in tasks for manufacturing.</p>
35

Detection of celery (Apium graveolens) in food with Real-Time PCR

Afshari Kashanian, Elisa January 2006 (has links)
<p>Directive EC 2003/89/EC of the European Parliament and of the Council states that certain</p><p>ingredients and products derived there of known to cause allergen reactions must always be</p><p>declared. Furthermore labelling is mandatory irrespective of the amount included. The National</p><p>Food Administration therefore needs methods for monitoring the presence of allergens in food.</p><p>Methods already exist for most of the allergens on the EU-list, but an operational method for</p><p>celery (Apium graveolens) is missing.</p><p>A specific DNA-method was developed, based on TaqMan Real-Time PCR with the celery</p><p>mannitol dehydrogenase gene as target sequence. The analysis was started with homogenisation</p><p>of the sample followed by extraction of DNA. The Real-Time PCR method was shown to be</p><p>specific for celery, producing a 113 bp fragment with two celery varieties and negative results</p><p>with other closely selected species commonly present together with celery in food products (12</p><p>samples). The detection limit was 2-20 pg DNA, which corresponds to 1-7 haploid genome</p><p>copies. When evaluated with model samples of celery in meat, a detection limit of less than</p><p>0,01 % was determined. When used to analyse food products from the market, six out of seven</p><p>products declared to contain celery were correctly identified as positive.</p>
36

Detection of celery (Apium graveolens) in food with Real-Time PCR

Afshari Kashanian, Elisa January 2006 (has links)
Directive EC 2003/89/EC of the European Parliament and of the Council states that certain ingredients and products derived there of known to cause allergen reactions must always be declared. Furthermore labelling is mandatory irrespective of the amount included. The National Food Administration therefore needs methods for monitoring the presence of allergens in food. Methods already exist for most of the allergens on the EU-list, but an operational method for celery (Apium graveolens) is missing. A specific DNA-method was developed, based on TaqMan Real-Time PCR with the celery mannitol dehydrogenase gene as target sequence. The analysis was started with homogenisation of the sample followed by extraction of DNA. The Real-Time PCR method was shown to be specific for celery, producing a 113 bp fragment with two celery varieties and negative results with other closely selected species commonly present together with celery in food products (12 samples). The detection limit was 2-20 pg DNA, which corresponds to 1-7 haploid genome copies. When evaluated with model samples of celery in meat, a detection limit of less than 0,01 % was determined. When used to analyse food products from the market, six out of seven products declared to contain celery were correctly identified as positive.
37

Real-time Transmission Over Internet

Gao, Qi January 2004 (has links)
With the Internet expansion, real-time transmission over Internet is becoming a new promising application. Successful real-time communication over IP networks requires reasonably reliable, low delay, low loss date transport. Since Internet is a non-synchronous packet switching network, high load and lack of guarantees on data delivery make real-time communication such as Voice and Video over IP a challenging application to become realistic on the Internet. This thesis work is composed of two parts within real-time voice and video communication: network simulation and measurement on the real Internet. In the network simulation, I investigate the requirement for the network"overprovisioning"in order to reach certain quality-of-service. In the experiments on the real Internet, I simulate real-time transmission with UDP packets along two different traffic routes and analyze the quality-of- service I get in each case. The overall contribution of this work is: To create scenarios to understand the concept of overprovisioning and how it affects the quality-of-service. To develop a mechanism to measure the quality-of-service for real-time traffic provided by the current best-effort network.
38

New Interface for Rapid Feedback Control on ABB-Robots

Lundqvist, Rasmus, Söreling, Tobias January 2005 (has links)
Automation in manufacturing has come far by using industrial robots. However, industrial robots require tremendous efforts in static calibration due to their lack of senses. Force and vision are the most useful sensing capabilities for a robot system operating in an unknown or uncalibrated environment [4]and by integrating sensors in real-time with industrial robot controllers, dynamic processes need far less calibration which leads to reduced lead time. By using robot systems which are more dynamic and can perform complex tasks with simple instructions, the production efficiency will rise and hence also the profit for companies using them. Although much research has been presented within the research community, current industrial robot systems have very limited support for external sensor feedback, and the state-of-the-art robots today have generally no feedback loop that can handle external force- or position controlled feedback. Where it exists, feedback at the rate of 10 Hz is considered to berare and is far from real-time control. A new system where the feedback control can be possible within a real-time behavior, developed at Lund Institute of Technology, has been implemented and deployed at Linköping Institute of Technology. The new system for rapid feedback control is a highly complex system, possible to install in existing robot cells, and enables real-time (250 Hz) sensor feedback to the robot controller. However, the system is not yet fully developed, and a lot of issues need to be considered before it can reach the market in other than specific applications. The implementation and deployment of the new interface at LiTH shows that the potential for this system is large, since it makes production with robots exceedingly flexible and dynamic, and the fact that the system works with real- time feedback makes industrial robots more useful in tasks for manufacturing.
39

A Depth of Field Algorithm for Realtime 3D Graphics in OpenGL / Algoritm i OpenGL för att rendera realtids 3D grafik med fokus

Henriksson, Ola January 2002 (has links)
<p>The company where this thesis was formulated constructs VR applications for the medical environment. The hardware used is ordinary dektops with consumer level graphics cards and haptic devices. In medicin some operations require microscopes or cameras. In order to simulate these in a virtual reality environment for educational purposes, the effect of depth of field or focus have to be considered. </p><p>A working algorithm that generates this optical occurence in realtime, stereo rendered computer graphics is presented in this thesis. The algorithm is implemented in OpenGL and C++ to later be combined with a VR application simulating eye-surgery which is built with OpenGL Optimizer. </p><p>Several different approaches are described in this report. The call for realtime stereo rendering (~60 fps) means taking advantage of the graphics hardware to a great extent. In OpenGL this means using the extensions to a specific graphic chip for better performance, in this case the algorithm is implemented for a GeForce3 card. </p><p>To increase the speed of the algorithm much of the workload is moved from the CPU to the GPU (Graphics Processing Unit). By re-defining parts of the ordinary OpenGL pipeline via vertex programs, a distance-from-focus map can be stored in the alpha channel of the final image with little time loss. </p><p>This can effectively be used to blend a previously blurred version of the scene with a normal render. Different techniques to quickly blur a renderedimage is discussed, to keep the speed up solutions that require moving data from the graphics card is not an option.</p>
40

Implementation Of A Wireless Streaming System For Universal Multimedia Access

Unal, Halim Unsem 01 January 2003 (has links) (PDF)
This thesis describes a universal multimedia access system and its implementation details. In the context of this thesis, universal multimedia access means accessing multimedia content over ubiquitous computer networks, using different computing platforms. The computer networks involve both wired and wireless networks, and computing platforms involve wired PC&rsquo / s, mobile PC&rsquo / s and personal digital assistants (PDA). The system is built on client/server architecture. Video data is H.263 coded and carried over RTP. Java Media Framework is utilized and its capabilities are extended with special plug-ins when necessary.

Page generated in 0.0478 seconds