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Dissertations / Theses on the topic 'Methods of video data transmission'

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Published: 30 May 2022
Last updated: 31 May 2022

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1

Ліпчанська, Оксана Валентинівна. "Методи обробки та передачі даних для підсистеми інформаційного забезпечення машиніста локомотива." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41022.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.13.05 – комп'ютерні системи та компоненти. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019. У дисертації вирішена задача розробки методів обробки та передачі даних для підсистеми інформаційного забезпечення машиніста локомотива. На підставі вивчення сучасних методів і засобів обробки і передачі даних на залізничному транспорті встановлено, що існує суперечність між підвищенням швидкості та інтенсивності руху залізничного транспорту, збільшенням кількості аварійно-небезпечних ділянок, ускладненням системи управління залізничним транспортом, підвищенням вимог до якості інформаційного забезпечення машиніста локомотива та застосовуваними математичним апаратом і технологіями управління кодування/декодування. Обґрунтовано вибір технології математичної формалізації на основі мереж масового обслуговування та нейронних мереж. Розроблено концептуальну модель бездротового сегменту підсистеми інформаційного забезпечення машиніста локомотива, яка побудована з використанням технології 4G і враховує тип модуляції QPSK та процедуру перемежіння при передачі кадрів для зниження ймовірності помилкового прийому при забезпеченні високої швидкості передачі даних. Розроблено математичну модель процесу передачі даних по фізичному розподіленому uplink каналу, яка враховує особливості передачі даних відповідно до стандарту LTE в динамічних умовах магістралі залізниці і дозволяє оцінити ймовірносно-часові характеристики процесу передачі даних в підсистемі інформаційного забезпечення машиніста локомотива. Розроблено математичну модель управління доступом до сегменту комп'ютеризованої системи залізничного транспорту, яка враховує особливості передачі даних відповідно до стандарту LTE в динамічних умовах магістралі залізниці. Удосконалено процедуру завадостійкого декодування потокового відео, що передається в бездротовому сегменті 4G мережі підсистеми інформаційного забезпечення машиніста локомотива, що дозволяє підвищити оперативність при передачі даних, скоротити загальну кількість обчислень при декодуванні і звільнити обчислювальні ресурси комп'ютеризованої системи. Розроблено інтелектуальну систему контролю стану небезпечних ділянок залізничного шляху із застосуванням адаптованої згортальної нейронної мережі, що дозволяє підвищити достовірність розпізнавання небезпечних ситуацій на залізничних переїздах і інформувати машиніста в разі виникнення критичної ситуації. Обґрунтовано практичні рекомендації щодо застосування розроблених методів.
The thesis is in candidacy for a scientific degree of candidate of technical sciences in specialty 05.13.05 – computer systems and components. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis solves the problem of developing methods for processing and transmitting data for the locomotive driver's information support subsystem. Based on the study of modern methods and means of processing and transmitting data on railway transport, it is established that there is a contradiction between the increase in the speed and intensity of railway traffic, the increase in the number of emergency areas, the complexity of the railway transport management system, the increase in the requirements for railway transport safety and the applied mathematical apparatus and technologies of coding / decoding. The choice of technology of mathematical formalization based on queuing networks and neural networks is justified. A conceptual model of the wireless segment of the locomotive driver's information support subsystem has been developed, which is built using 4G technology and takes into account the QPSK modulation type and the interleaving procedure for frame transmission to reduce the probability of erroneous reception while ensuring a high data rate. A mathematical model of the process of transmitting video data over a physical distributed uplink channel that takes into account the peculiarities of video data transmission in accordance with the LTE standard under dynamic conditions of the railway main line is developed and allows to estimate a wide range of robabilitytemporal characteristics of the video data transmission process in the locomotive driver's information support subsystem. A mathematical model of access control to the segment of a locomotive driver's information support subsystem has been developed, which takes into account the peculiarities of video data transmission in accordance with the LTE standard in the dynamic conditions of the railway line. The procedure for noiseless decoding of streaming video in the wireless 4G network segment of the locomotive driver’s information support subsystem is improved. It allows to increase efficiency in data transfer, to reduce the total number of calculations during decoding and to release the computing resources of the computerized system. An intelligent system for monitoring the state of dangerous sections of the railway using an adapted convolution neural network has been developed, which makes it possible to increase the reliability of the recognition of dangerous situations at railway crossings and inform the driver in the event of a critical situation. Practical recommendations as for the developed methods application are substantiated.
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2

Ліпчанська, Оксана Валентинівна. "Методи обробки та передачі даних для підсистеми інформаційного забезпечення машиніста локомотива." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40900.

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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.13.05 – комп'ютерні системи та компоненти. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019. У дисертації вирішена задача розробки методів обробки та передачі даних для підсистеми інформаційного забезпечення машиніста локомотива. На підставі вивчення сучасних методів і засобів обробки і передачі даних на залізничному транспорті встановлено, що існує суперечність між підвищенням швидкості та інтенсивності руху залізничного транспорту, збільшенням кількості аварійно-небезпечних ділянок, ускладненням системи управління залізничним транспортом, підвищенням вимог до якості інформаційного забезпечення машиніста локомотива та застосовуваними математичним апаратом і технологіями управління кодування/декодування. Обґрунтовано вибір технології математичної формалізації на основі мереж масового обслуговування та нейронних мереж. Розроблено концептуальну модель бездротового сегменту підсистеми інформаційного забезпечення машиніста локомотива, яка побудована з використанням технології 4G і враховує тип модуляції QPSK та процедуру перемежіння при передачі кадрів для зниження ймовірності помилкового прийому при забезпеченні високої швидкості передачі даних. Розроблено математичну модель процесу передачі даних по фізичному розподіленому uplink каналу, яка враховує особливості передачі даних відповідно до стандарту LTE в динамічних умовах магістралі залізниці і дозволяє оцінити ймовірносно-часові характеристики процесу передачі даних в підсистемі інформаційного забезпечення машиніста локомотива. Розроблено математичну модель управління доступом до сегменту комп'ютеризованої системи залізничного транспорту, яка враховує особливості передачі даних відповідно до стандарту LTE в динамічних умовах магістралі залізниці. Удосконалено процедуру завадостійкого декодування потокового відео, що передається в бездротовому сегменті 4G мережі підсистеми інформаційного забезпечення машиніста локомотива, що дозволяє підвищити оперативність при передачі даних, скоротити загальну кількість обчислень при декодуванні і звільнити обчислювальні ресурси комп'ютеризованої системи. Розроблено інтелектуальну систему контролю стану небезпечних ділянок залізничного шляху із застосуванням адаптованої згортальної нейронної мережі, що дозволяє підвищити достовірність розпізнавання небезпечних ситуацій на залізничних переїздах і інформувати машиніста в разі виникнення критичної ситуації. Обґрунтовано практичні рекомендації щодо застосування розроблених методів.
The thesis is in candidacy for a scientific degree of candidate of technical sciences in specialty 05.13.05 – computer systems and components. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis solves the problem of developing methods for processing and transmitting data for the locomotive driver's information support subsystem. Based on the study of modern methods and means of processing and transmitting data on railway transport, it is established that there is a contradiction between the increase in the speed and intensity of railway traffic, the increase in the number of emergency areas, the complexity of the railway transport management system, the increase in the requirements for railway transport safety and the applied mathematical apparatus and technologies of coding / decoding. The choice of technology of mathematical formalization based on queuing networks and neural networks is justified. A conceptual model of the wireless segment of the locomotive driver's information support subsystem has been developed, which is built using 4G technology and takes into account the QPSK modulation type and the interleaving procedure for frame transmission to reduce the probability of erroneous reception while ensuring a high data rate. A mathematical model of the process of transmitting video data over a physical distributed uplink channel that takes into account the peculiarities of video data transmission in accordance with the LTE standard under dynamic conditions of the railway main line is developed and allows to estimate a wide range of robabilitytemporal characteristics of the video data transmission process in the locomotive driver's information support subsystem. A mathematical model of access control to the segment of a locomotive driver's information support subsystem has been developed, which takes into account the peculiarities of video data transmission in accordance with the LTE standard in the dynamic conditions of the railway line. The procedure for noiseless decoding of streaming video in the wireless 4G network segment of the locomotive driver’s information support subsystem is improved. It allows to increase efficiency in data transfer, to reduce the total number of calculations during decoding and to release the computing resources of the computerized system. An intelligent system for monitoring the state of dangerous sections of the railway using an adapted convolution neural network has been developed, which makes it possible to increase the reliability of the recognition of dangerous situations at railway crossings and inform the driver in the event of a critical situation. Practical recommendations as for the developed methods application are substantiated.
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3

Yilmaz, Ayhan. "Robust Video Transmission Using Data Hiding." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1093509/index.pdf.

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Video transmission over noisy wireless channels leads to errors on video, which degrades the visual quality notably and makes error concealment an indispensable job. In the literature, there are several error concealment techniques based on estimating the lost parts of the video from the available data. Utilization of data hiding for this problem, which seems to be an alternative of predicting the lost data, provides a reserve information about the video to the receiver while unchanging the transmitted bit-stream syntax
hence, improves the reconstruction video quality without significant extra channel utilization. A complete error resilient video transmission codec is proposed, utilizing imperceptible embedded information for combined detecting, resynchronization and reconstruction of the errors and lost data. The data, which is imperceptibly embedded into the video itself at the encoder, is extracted from the video at the decoder side to be utilized in error concealment. A spatial domain error recovery technique, which hides edge orientation information of a block, and a resynchronization technique, which embeds bit length of a block into other blocks are combined, as well as some parity information about the hidden data, to conceal channel errors on intra-coded frames of a video sequence. The errors on inter-coded frames are basically recovered by hiding motion vector information along with a checksum into the next frames. The simulation results show that the proposed approach performs superior to conventional approaches for concealing the errors in binary symmetric channels, especially for higher bit rates and error rates.
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4

Dissanayake, Maheshi Buddhinee. "Error robust video transmission using redundant data." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521720.

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5

Walker, Wendy Tolle 1959. "Video data compression for telescience." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276830.

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This paper recommends techniques to use for data compression of video data used to point a telescope and from a camera observing a robot, for transmission from the proposed U.S. Space Station to Earth. The mathematical basis of data compression is presented, followed by a general review of data compression techniques. A technique that has wide-spread use in data compression of videoconferencing images is recommended for the robot observation data. Bit rates of 60 to 400 kbits/sec can be achieved. Several techniques are modelled to find a best technique for the telescope data. Actual starfield images are used for the evaluation. The best technique is chosen on the basis of which model provides the most compression while preserving the important information in the images. Compression from 8 bits per pel to 0.015 bits per pel is achieved.
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6

Malindi, Phumzile. "Methods for providing rural telemedicine with quality video transmission." Thesis, Cape Peninsula University of Technology, 2007. http://hdl.handle.net/20.500.11838/1197.

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Thesis (DTech (Electrical engineering))--Cape Peninsula University of Technology, Cape Town, 2007
Telemedicine has been identified as a tool to distnllUte medical expertise to medically underserved rural community. However, due to the underdeveloped or non-existent telecommunication infrastructure, which is needed as the platform for telemedicine, the full benefits of telemedicine are yet to be realized in most parts of South Africa and Africa as a whole. This study aims to explore ways on how to provide lP-based lCI system that can be used as a communication platform for telemedicine in rural areas. In order to emulate the onsite face-to-face consultation experience, the rural telemedicine system must be able to provide quality video transmission. Quality video is also important in order for the physician at the distant end to be able to make correct diagnosis. Hence the main focus of this study is on ways ofproviding quality video over lP-based multiservice network. A conceptual model of a rural area network that can be used for rural telemedicine has been deVeloped, and different access technologies that can be used for rural areas are presented. Techniques for compesating IP best effort datagram delivery are provided. Factors that can affect the quality of video transmission on an lP-based packet network are identified, and a holistic approach to mitigate them is proposed. That includes adopting coding techniques that will provide coding efficiency, high quality video that is consistent at high and low bit rates, resilience to transmission errors, scalability, and network friendliness, which will result in perceived quality improvement, highcompression efficiency, and possibility of transportation over different networks. Secondly, it also includes mechanisms to compensate for packet networks idiosyncrasy, especially JP best-effort debilities, in order to meet the latency and jitter requirements of real-time video traffic. For video coding, H.264 is proposed as it meets most of the encoding requirements listed above, and for prioritising and protecting.video traffic from JP network's best-effort debilities a combination of differential services (DiflServ) and multi-protocol label switching (MPLS) have been adopted, where DiflServ is used for traffic classification and MPLS is used for traffic engineering and fast-rerouting in the event of route failure. To verify and validate the proposed solutions, modelling and simulation has been used, where the Network Simulator (NS-2.93) has been used to simulate network functions, and PSNR, VQM score and double stimulus impairment scale (DSIS) have been used for evaluating video quality.
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Tudor-Jones, Gareth. "Concealment algorithms for networked video transmission systems." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/32996.

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This thesis addresses the problem of cell loss when transmitting video data over an ATM network. Cell loss causes sections of an image to be lost or discarded in the interconnecting nodes between the transmitting and receiving locations. The method used to combat this problem is to use a technique called Error Concealment, where the lost sections of an image are replaced with approximations derived from the information in the surrounding areas to the error. This technique does not require any additional encoding, as used by Error Correction. Conventional techniques conceal from within the pixel domain, but require a large amount of processing (2N2 up to 20N2) where N is the dimension of an N×N square block. Also, previous work at Loughborough used Linear Interpolation in the transform domain, which required much less processing, to conceal the error.
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8

Brauer, David A. "EMBEDDED VIDEO TRANSMISSION IN A CAIS DATA ACQUISITION SYSTEM." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/608287.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
Acquiring real-time video data, during flight testing, has become an integral component in aircraft design and performance evaluation. This unique data acquisition capability has been successfully integrated into the JSF (Joint Strike Fighter), CAIS compliant, FTIDAS (Flight Test Instrumentation Data Acquisition System) developed by L-3 Communications Telemetry-East.
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9

Walker, Thaddeus Owens. "Real-time compressed video transmission across the common data link." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA304462.

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Thesis (M.S. in Electrical Engineering and Electrical Engineer) Naval Postgraduate School, June 1995.
Thesis advisor(s): Murali Tummala, S.B. Shukla. "June 1995." Includes bibliographical references. Also available online.
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10

Azari, Jian. "Transmission of mixed video, speech and data services over ATM networks." Thesis, University of Essex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333498.

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11

Wang, Yubing. "Modeling and evaluating feedback-based error control for video transfer." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-102408-150542/.

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12

Chen, Wu-hsiang Jonas. "Error-resilient techniques for packet video communications /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5850.

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13

Jelveh, Hossein. "Motion compensation algorithms for very low bit rate transmission of video conferencing data." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307252.

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14

Tsoi, Yiu-lun Kelvin, and 蔡耀倫. "Real-time scheduling techniques with QoS support and their applications in packet video transmission." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31221786.

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15

Kim, Minjung. "Quality of service support for progressive video transmission over Internet." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180252/unrestricted/kim%5Fminjung%5F200312%5Fphd.pdf.

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Srinivas, Bindignavile S. "Progressive image and video transmission with error concealment on burst error channels and lossy packet networks /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6015.

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17

Danyali, Habibollah. "Highly scalable wavelet image and video coding for transmission over heterogeneous networks." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20041027.115306/index.html.

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Johnston, B. A. "Investigation of methods for secure transmission of digital data at high speed." Thesis, University of Hertfordshire, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377565.

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19

Wang, Dongmei. "Video coding and transmission for multimedia communications using a 3-D graphics model." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13836.

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20

Irestål, Erik. "Break out Box for Transmission of Synchronous Video and CAN Data Streams over Gigabit Ethernet." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18377.

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Active safety systems for automobiles in the form of camera systems have evolved rapidly the last ten years, Autoliv Electronics in Linköping develops multiple such systems. In their development process there is a need for a Break out Box (BoB) to record and playback video and CAN data as if the camera system was used in an actual automobile. The aim of this thesis has been to develop a BoB for these camera systems. The work has been divided into three phases; identification of requirements, design of the BoB and implementation of a prototype. The project has addressed four known issues with the currently used BoB; bandwidth, modularity, synchronization and usability. The result is a new BoB which is based on an FPGA connecting to a PC over Gigabit Ethernet. The design is an extendible platform for multiple channels of video, CAN data, other serial data and future extensions. A prototype proves the design concept by successfully recording video for the Autoliv NightVision system onto a PC.

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21

Bayrakeri, Sadik. "Scalable video coding using spatio-temporal interpolation." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/15385.

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22

Kachejian, Kerry C. "A systems approach to portable tactical video datalinks." Master's thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-03172010-020046/.

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23

wang, yubing. "Modeling and Evaluating Feedback-Based Error Control for Video Transfer." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-dissertations/397.

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"Packet loss can be detrimental to real-time interactive video over lossy networks because one lost video packet can propagate errors to many subsequent video frames due to the encoding dependency between frames. Feedback-based error control techniques use feedback information from the decoder to adjust coding parameters at the encoder or retransmit lost packets to reduce the error propagation due to data loss. Feedback-based error control techniques have been shown to be more effective than trying to conceal the error at the encoder or decoder alone since they allow the encoder and decoder to cooperate in the error control process. However, there has been no systematic exploration of the impact of video content and network conditions on the performance of feedback-based error control techniques. In particular, the impact of packet loss, round-trip delay, network capacity constraint, video motion and reference distance on the quality of videos using feedback-based error control techniques have not been systematically studied. This thesis presents analytical models for the major feedback-based error control techniques: Retransmission, Reference Picture Selection (both NACK and ACK modes) and Intra Update. These feedback-based error control techniques have been included in H.263/H.264 and MPEG4, the state of the art video in compression standards. Given a round-trip time, packet loss rate, network capacity constraint, our models can predict the quality for a streaming video with retransmission, Intra Update and RPS over a lossy network. In order to exploit our analytical models, a series of studies has been conducted to explore the effect of reference distance, capacity constraint and Intra coding on video quality. The accuracy of our analytical models in predicting the video quality under different network conditions is validated through simulations. These models are used to examine the behavior of feedback-based error control schemes under a variety of network conditions and video content through a series of analytic experiments. Analysis shows that the performance of feedback-based error control techniques is affected by a variety of factors including round-trip time, loss rate, video content and the Group of Pictures (GOP) length. In particular: 1) RPS NACK achieves the best performance when loss rate is low while RPS ACK outperforms other repair techniques when loss rate is high. However RPS ACK performs the worst when loss rate is low. Retransmission performs the worst when the loss rate is high; 2) for a given round-trip time, the loss rate where RPS NACK performs worse than RPS ACK is higher for low motion videos than it is for high motion videos; 3) Videos with RPS NACK always perform the same or better than videos without repair. However, when small GOP sizes are used, videos without repair perform better than videos with RPS ACK; 4) RPS NACK outperform Intra Update for low-motion videos. However, the performance gap between RPS NACK and Intra Update drops when the round-trip time or the intensity of video motion increases. 5) Although the above trends hold for both VQM and PSNR, when VQM is the video quality metric the performance results are much more sensitive to network loss. 6) Retransmission is effective only when the round-trip time is low. When the round-trip time is high, Partial Retransmission achieves almost the same performance as Full Retransmission. These insights derived from our models can help determine appropriate choices for feedback-based error control techniques under various network conditions and video content. "
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Deivakkannu, Ganesan. "Data acquisition and data transfer methods for real-time power system optimisation problems solution." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/1178.

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Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014
The electric power utilities play a vital role in the generation, transmission and distribution of the electrical power to the end users. The power utilities face two major issues, i.e. i) power grids are expected to operate close to the maximum capacity, and ii) there is a need for accurate and better monitoring and control of the power system network using the modern technology and the available tools. These two issues are interconnected as better monitoring allows for better control of the power system. Development of the new standard-based power system technologies contributed to raising the ideas for building of a Smart grid. The challenges are that this process requires development of new control and operation architectures and methods for data acquisition, data transfer, and control computation. These methods require data for the full dynamic state of the power system in real-time, which leads to the introduction of the synchrophasor-based monitoring and control of the power system. The thesis describes the research work and investigations for integration of the existing new power system technologies to build fully automated systems for real-time solution of power system energy management problems, incorporating data measurement and acquisition, data transfer and distribution through a communication network, and data storage and retrieval in one whole system.
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Klein, Michael Erwin Carleton University Dissertation Engineering Mechanical. "Development and comparison of data transfer methods for h-adaptive finite element analysis." Ottawa, 1992.

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Ridgewell, Alexander Graham, and n/a. "A Method for Efficient Transmission of XML Data across a Network." University of Canberra. School of Information Sciences & Engineering, 2007. http://erl.canberra.edu.au./public/adt-AUC20070801.151913.

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Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML (ISO 8879), which is a well defined, public standard. It uses plain text to encode a hierarchical set of information using verbose tags to allow the XML document to be understood without any special reader. The use of schemas in XML also allows a well defined contract describing what a single XML document means. The self-contained nature of XML and the strong contract provided by its schemas makes it useful as an archival storage format and as a means of communicating across system or organizational boundaries. As such XML is being increasingly used by businesses throughout the world. These businesses use XML as a means of storing, transmitting and (with the use of style sheets) displaying information. The simple, well defined structure of XML does present some problems when it is used by businesses and similar organizations. As it is an open, plain text based standard care must be taken when looking at security. The use of plain text with verbose tags also results in XML documents that are far larger than other means of storing the same information. This thesis focuses on the affect of the large size of XML when it is used to communicate across a network. This large size can often increase the time taken to transmit the document and we were interested to see how it could be minimized. we investigated the ways that are used to control the size of XML documents and how they are transmitted. We carefully investigated by implementing solutions on how to transmit the XML document. We then first presented a new method, called dynamic adaptive threshold transmission (DATT), in comparisons with other existing similar methods, which, under the discussed conditions, offers significant improvements in transmission times and network transmission efficiencies.
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Lu, Jie. "Performance evaluation of packet video transfer over local area networks." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06162009-063207/.

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Chong, Luis A. Caceres. "DYNAMAC media distribution system /." Online version of thesis, 2007. http://hdl.handle.net/1850/5545.

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Hui, Kin Cheung. "The design and implementation of a MPEG video system with transmission control and QoS support." HKBU Institutional Repository, 2002. http://repository.hkbu.edu.hk/etd_ra/446.

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Huang, Jie. "Efficient Support for Application-Specific Video Adaptation." PDXScholar, 2006. https://pdxscholar.library.pdx.edu/open_access_etds/2670.

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As video applications become more diverse, video must be adapted in different ways to meet the requirements of different applications when there are insufficient resources. In this dissertation, we address two sorts of requirements that cannot be addressed by existing video adaptation technologies: (i) accommodating large variations in resolution and (ii) collecting video effectively in a multi-hop sensor network. In addition, we also address requirements for implementing video adaptation in a sensor network. Accommodating large variation in resolution is required by the existence of display devices with widely disparate screen sizes. Existing resolution adaptation technologies usually aim at adapting video between two resolutions. We examine the limitations of these technologies that prevent them from supporting a large number of resolutions efficiently. We propose several hybrid schemes and study their performance. Among these hybrid schemes, Bonneville, a framework that combines multiple encodings with limited scalability, can make good trade-offs when organizing compressed video to support a wide range of resolutions. Video collection in a sensor network requires adapting video in a multi-hop storeand- forward network and with multiple video sources. This task cannot be supported effectively by existing adaptation technologies, which are designed for real-time streaming applications from a single source over IP-style end-to-end connections. We propose to adapt video in the network instead of at the network edge. We also propose a framework, Steens, to compose adaptation mechanisms on multiple nodes. We design two signaling protocols in Steens to coordinate multiple nodes. Our simulations show that in-network adaptation can use buffer space on intermediate nodes for adaptation and achieve better video quality than conventional network-edge adaptation. Our simulations also show that explicit collaboration among multiple nodes through signaling can improve video quality, waste less bandwidth, and maintain bandwidth-sharing fairness. The implementation of video adaptation in a sensor network requires system support for programmability, retaskability, and high performance. We propose Cascades, a component-based framework, to provide the required support. A prototype implementation of Steens in this framework shows that the performance overhead is less than 5% compared to a hard-coded C implementation.
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31

Lei, Chan Un. "Comparison of different correlating methods for the single-phase heat transfer data in laminar and turbulent flow regions." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2493964.

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32

Ibrahim, Abdulkareem B. "Error resilience and concealment in MVC video over wireless networks." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/10484.

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Multi-view video is capable of presenting a full and accurate depth perception of a scene. The concept of multi-view video is becoming more useful especially in 3D display systems by enhancing the viewing of high resolution stereoscopic images from arbitrary viewpoints without the use of any special glasses. Like monoscopic video, the multi-view video is faced with different challenges such as: reliable compression, storage and bandwidth due to the increased number of views as well as the high sensitivity to transmission errors. All these may lead to a detrimental effect on the reconstructed views. The work in this thesis investigates the problems and challenges of transmission losses in a multi-view video bitstream over error prone wireless networks. Based on the network simulation results, the proposed technique is capable of addressing the problem of transmission losses. In practical wireless networks, transmission errors are inevitable and pose a serious challenge to the coded video data. The aim of this research effort is to examine the effect of these errors in a multi-view video bitstream when transmitted over a lossy channel. Moreover, this research work aims to develop a novel scheme that can make the multi-view coded videos more robust to transmission errors by minimizing the error effects and improving the perceptual quality. Multi-layer data partitioning as an error resilient technique is developed in JMVC 8.5 reference software in order to make the multi-view video bitstream more robust during transmission. In addition to that, we propose a simple decoding scheme that can support the decoding of the multi-layer data partitioning bitstream over channels with high error rate. The proposed technique is benchmarked with the already existing H.264/AVC data partitioning technique. The work in this thesis also employs the use of group of pictures as a coding parameter to investigate and reduce the effects of transmission errors in multi-view video transmitted over a very high error rate channel. The experiments are carried out with different error loss rates in order to evaluate the performance of these techniques in terms of perceptual quality when transmitted over a simulated erroneous channel. Errors are introduced using the Sirannon network simulator. The error performance of each technique is evaluated and analysed both objectively and subjectively after reconstruction. The results of the research investigation and simulation are presented and analysed in chapter six of the thesis.
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Hamlet, Sean Michael. "COMPARING ACOUSTIC GLOTTAL FEATURE EXTRACTION METHODS WITH SIMULTANEOUSLY RECORDED HIGH-SPEED VIDEO FEATURES FOR CLINICALLY OBTAINED DATA." UKnowledge, 2012. http://uknowledge.uky.edu/ece_etds/12.

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Accurate methods for glottal feature extraction include the use of high-speed video imaging (HSVI). There have been previous attempts to extract these features with the acoustic recording. However, none of these methods compare their results with an objective method, such as HSVI. This thesis tests these acoustic methods against a large diverse population of 46 subjects. Two previously studied acoustic methods, as well as one introduced in this thesis, were compared against two video methods, area and displacement for open quotient (OQ) estimation. The area comparison proved to be somewhat ambiguous and challenging due to thresholding effects. The displacement comparison, which is based on glottal edge tracking, proved to be a more robust comparison method than the area. The first acoustic methods OQ estimate had a relatively small average error of 8.90% and the second method had a relatively large average error of -59.05% compared to the displacement OQ. The newly proposed method had a relatively small error of -13.75% when compared to the displacements OQ. There was some success even though there was relatively high error with the acoustic methods, however, they may be utilized to augment the features collected by HSVI for a more accurate glottal feature estimation.
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Karlsson, Linda S. "Spatio-Temporal Pre-Processing Methods for Region-of-Interest Video Coding." Licentiate thesis, Mid Sweden University, Department of Information Technology and Media, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-51.

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In video transmission at low bit rates the challenge is to compress the video with a minimal reduction of the percieved quality. The compression can be adapted to knowledge of which regions in the video sequence are of most interest to the viewer. Region of interest (ROI) video coding uses this information to control the allocation of bits to the background and the ROI. The aim is to increase the quality in the ROI at the expense of the quality in the background. In order for this to occur the typical content of an ROI for a particular application is firstly determined and the actual detection is performed based on this information. The allocation of bits can then be controlled based on the result of the detection.

In this licenciate thesis existing methods to control bit allocation in ROI video coding are investigated. In particular pre-processing methods that are applied independently of the codec or standard. This makes it possible to apply the method directly to the video sequence without modifications to the codec. Three filters are proposed in this thesis based on previous approaches. The spatial filter that only modifies the background within a single frame and the temporal filter that uses information from the previous frame. These two filters are also combined into a spatio-temporal filter. The abilities of these filters to reduce the number of bits necessary to encode the background and to successfully re-allocate these to the ROI are investigated. In addition the computational compexities of the algorithms are analysed.

The theoretical analysis is verified by quantitative tests. These include measuring the quality using both the PSNR of the ROI and the border of the background, as well as subjective tests with human test subjects and an analysis of motion vector statistics.

The qualitative analysis shows that the spatio-temporal filter has a better coding efficiency than the other filters and it successfully re-allocates the bits from the foreground to the background. The spatio-temporal filter gives an improvement in average PSNR in the ROI of more than 1.32 dB or a reduction in bitrate of 31 % compared to the encoding of the original sequence. This result is similar to or slightly better than the spatial filter. However, the spatio-temporal filter has a better performance, since its computational complexity is lower than that of the spatial filter.

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Szolgay, Daniel. "Video event detection and visual data pro cessing for multimedia applications." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14313/document.

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Cette thèse (i) décrit une procédure automatique pour estimer la condition d'arrêt des méthodes de déconvolution itératives basées sur un critère d'orthogonalité du signal estimé et de son gradient à une itération donnée; (ii) présente une méthode qui décompose l'image en une partie géométrique (ou "cartoon") et une partie "texture" en utilisation une estimation de paramètre et une condition d'arrêt basées sur la diffusion anisotropique avec orthogonalité, en utilisant le fait que ces deux composantes. "cartoon" et "texture", doivent être indépendantes; (iii) décrit une méthode pour extraire d'une séquence vidéo obtenue à partir de caméra portable les objets de premier plan en mouvement. Cette méthode augmente la compensation de mouvement de la caméra par une nouvelle estimation basée noyau de la fonction de probabilité de densité des pixels d'arrière-plan. Les méthodes présentées ont été testées et comparées aux algorithmes de l'état de l'art
This dissertation (i) describes an automatic procedure for estimating the stopping condition of non-regularized iterative deconvolution methods based on an orthogonality criterion of the estimated signal and its gradient at a given iteration; (ii) presents a decomposition method that splits the image into geometric (or cartoon) and texture parts using anisotropic diffusion with orthogonality based parameter estimation and stopping condition, utilizing the theory that the cartoon and the texture components of an image should be independent of each other; (iii) describes a method for moving foreground object extraction in sequences taken by wearable camera, with strong motion, where the camera motion compensated frame differencing is enhanced with a novel kernel-based estimation of the probability density function of the background pixels. The presented methods have been thoroughly tested and compared to other similar algorithms from the state-of-the-art
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Anderson-Trocme, Paul. "An evaluation of the operations and safety issues at reserved lane facilities using microscopic video data and alternative methods." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123157.

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This research investigates the operating performance and safety issues of reserved lanes in Quebec, Canada using microscopic data and different methods. Reserved lanes have been around for a few decades in North America, however their effectiveness and safety along congested facilities remains contested. This thesis proposes original methods for collecting microscopic data, analysing and evaluating the performance and safety of reserved lane highway and arterial facilities. The microscopic data (vehicle level data) is collected using video cameras and obtained with an open-source feature-based tracking software. As a first objective, this research work evaluates the accuracy of the automatically calculated speed data by comparing them to manually collected speeds from different camera orientations and concludes that the mean errors are comparable to the current collection technologies. The second part of the research applies the tracked vehicle data from an exclusive bus lane to a microsimulation scenario and calibrates the speeds along the corridor to estimate its effects on the overall performance and emissions. The third section analyses the performance and safety along highway and arterial facilities. The highway segment was evaluated before and after the implementation of an HOV lane by investigating the differences in volumes, speeds and travel times. The arterial segment with a reserved bus lane was evaluated based on lane change violation rates and surrogate safety indicators calculated using trajectory-based tools. Countermeasures for both facilities are discussed based on the results extracted using the alternative data collection process. Overall, the research highlights the video-based application's ability to generate microscopic traffic data and presents new methods that can be implemented along facilities to monitor, build microscopic models and evaluate reserved lanes based on different driver behavior indicators.
Cette recherche examine les performances et la sécurité des voies réservées au Québec à partir de données microscopiques en utilisant des nouvelles méthodes. La construction de voies réservées a débuté pendant les années 1970 en Amérique du Nord, mais leur efficacité ainsi que leur sécurité au long des routes congestionnées reste contesté. Cette thèse propose des méthodes originales de collecte de données microscopiques, d'analyse et d'évaluation de la performance et la sécurité des voies réservées sur les autoroutes et les artères. Les données microscopiques (au niveau du véhicule) sont collectées avec l'aide de caméras vidéo et traitées avec un logiciel de suivi basé sur les caractéristiques des véhicules open-source. Dans un premier objectif, ce travail de recherche évalue l'exactitude des données de vitesse calculées automatiquement en les comparant aux vitesses recueillies manuellement de différentes orientations de la caméra et conclu que les erreurs moyennes sont comparable aux technologies de captage utilisé couramment. La deuxième partie de la recherche applique les données des véhicules voyageant sur une route avec une voie réservée d'autobus dans une microsimulation et étalonne les vitesses au long du corridor pour estimer ses effets sur la performance globale ainsi que les émissions. La troisième section analyse la performance et la sécurité des voies réservées le long des autoroutes et artères. Le segment de l'autoroute a été évalué avant et après la mise en œuvre d'une voie réservée en étudiant les différences de volumes, les vitesses et les temps de déplacement. Le segment artériel avec une voie réservée aux autobus a été évalué en fonction des taux d'abus pour les changements de voies et d'indicateurs de sécurité de substitution calculés en utilisant de outils d'analyse basés sur les trajectoires des véhicules. Les contremesures pour les deux installations sont discutées sur la base des résultats extraits en utilisant le nouveau processus de collecte et analyse de données. Dans l'ensemble, la recherche met en évidence la capacité de l'application de vidéo à produire des données de trafic microscopiques et présente des nouvelles méthodes qui peuvent être mise en œuvre le long des voies réservées, construire des modèles microscopiques et évaluer des voies réservées sur la base de différent indicateurs de comportement du conducteur.
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37

Huang, Defeng. "Low complexity diversity combining and carrier frequency offset compensation for ubiquitous OFDM based broadband wireless communications /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20HUANG.

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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 163-171). Also available in electronic version. Access restricted to campus users.
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Zhang, Jian Electrical Engineering Australian Defence Force Academy UNSW. "Error resilience for video coding services over packet-based networks." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Electrical Engineering, 1999. http://handle.unsw.edu.au/1959.4/38652.

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Error resilience is an important issue when coded video data is transmitted over wired and wireless networks. Errors can be introduced by network congestion, mis-routing and channel noise. These transmission errors can result in bit errors being introduced into the transmitted data or packets of data being completely lost. Consequently, the quality of the decoded video is degraded significantly. This thesis describes new techniques for minimising this degradation. To verify video error resilience tools, it is first necessary to consider the methods used to carry out experimental measurements. For most audio-visual services, streams of both audio and video data need to be simultaneously transmitted on a single channel. The inclusion of the impact of multiplexing schemes, such as MPEG 2 Systems, in error resilience studies is also an important consideration. It is shown that error resilience measurements including the effect of the Systems Layer differ significantly from those based only on the Video Layer. Two major issues of error resilience are investigated within this thesis. They are resynchronisation after error detection and error concealment. Results for resynchronisation using small slices, adaptive slice sizes and macroblock resynchronisation schemes are provided. These measurements show that the macroblock resynchronisation scheme achieves the best performance although it is not included in MPEG2 standard. The performance of the adaptive slice size scheme, however, is similar to that of the macroblock resynchronisation scheme. This approach is compatible with the MPEG 2 standard. The most important contribution of this thesis is a new concealment technique, namely, Decoder Motion Vector Estimation (DMVE). The decoded video quality can be improved significantly with this technique. Basically, this technique utilises the temporal redundancy between the current and the previous frames, and the correlation between lost macroblocks and their surrounding pixels. Therefore, motion estimation can be applied again to search in the previous picture for a match to those lost macroblocks. The process is similar to that the encoder performs, but it is in the decoder. The integration of techniques such as DMVE with small slices, or adaptive slice sizes or macroblock resynchronisation is also evaluated. This provides an overview of the performance produced by individual techniques compared to the combined techniques. Results show that high performance can be achieved by integrating DMVE with an effective resynchronisation scheme, even at a high cell loss rates. The results of this thesis demonstrate clearly that the MPEG 2 standard is capable of providing a high level of error resilience, even in the presence of high loss. The key to this performance is appropriate tuning of encoders and effective concealment in decoders.
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39

Wright, Beverly Darlene. "The impact of data collection methodology and warning labels on adolescents' response factors." restricted, 2005. http://etd.gsu.edu/theses/available/etd-08112005-232149/.

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Thesis (Ph. D.)--Georgia State University, 2005.
Title from title screen. Naveen Donthu, committee chair; Kenneth Bernhardt, Sevgin Eroglu, Detmar Straub, committee members. Electronic text (154 p. : ill. (some col.)). Description based on contents viewed Apr. 25, 2007. Includes bibliographical references (p. 139-154).
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Tsang, Yui Ming. "Optimal resource allocation algorithm with QoS and fairness supported for SDMA OFDM system /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20TSANGY.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 63-66). Also available in electronic version. Access restricted to campus users.
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41

Ramesh, Rajaram Posner Edward C. Posner Edward C. "Efficient multichannel methods for high-rate data transmission with application to ISDN (or) pouring water to get more out of copper /." Diss., Pasadena, Calif. : California Institute of Technology, 1992. http://resolver.caltech.edu/CaltechETD:etd-08082007-081649.

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42

Biswas, Shuchismita. "Power Grid Partitioning and Monitoring Methods for Improving Resilience." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104684.

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This dissertation aims to develop decision-making tools that aid power grid operators in mitigating extreme events. Two distinct areas are focused on: a) improving grid performance after a severe disturbance, and b) enhancing grid monitoring to facilitate timely preventive actions. The first part of the dissertation presents a proactive islanding strategy to split the bulk power transmission system into smaller self-adequate islands in order to arrest the propagation of cascading failures after an event. Heuristic methods are proposed to determine in what sequence should the island boundary lines be disconnected such that there are no operation constraint violations. The idea of optimal partitioning is further extended to the distribution network. A planning problem for determining which parts of the existing distribution grid can be converted to microgrids is formulated. This partitioning formulation addresses safety limits, uncertainties in load and generation, availability of grid-forming units, and topology constraints such as maintaining network radiality. Microgrids help maintain energy supply to critical loads during grid outages, thereby improving resilience. The second part of the dissertation focuses on wide-area monitoring using Phasor Measurement Unit (PMU) data. Strategies for data imputation and prediction exploiting the spatio-temporal correlation in PMU measurements are outlined. A deep-learning-based methodology for identifying the location of temporary power systems faults is also illustrated. As severe weather events become more frequent, and the threats from coordinated cyber intrusions increase, formulating strategies to reduce the impact of such events on the power grid becomes important; and the approaches outlined in this work can find application in this context.
Doctor of Philosophy
The modern power grid faces multiple threats, including extreme-weather events, solar storms, and potential cyber-physical attacks. Towards the larger goal of enhancing power systems resilience, this dissertation develops strategies to mitigate the impact of such extreme events. The proposed schemes broadly aim to- a) improve grid performance in the immediate aftermath of a disruptive event, and b) enhance grid monitoring to identify precursors of impending failures. To improve grid performance after a disruption, we propose a proactive islanding strategy for the bulk power grid, aimed at arresting the propagation of cascading failures. For the distribution network, a mixed-integer linear program is formulated for identifying optimal sub-networks with load and distributed generators that may be retrofitted to operate as self-adequate microgrids, if supply from the bulk power systems is lost. To address the question of enhanced monitoring, we develop model-agnostic, computationally efficient recovery algorithms for archived and streamed data from Phasor Measurement Units (PMU) with data drops and additive noise. PMUs are highly precise sensors that provide high-resolution insight into grid dynamics. We also illustrate an application where PMU data is used to identify the location of temporary line faults.
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43

Klaghstan, Merza. "Multimedia data dissemination in opportunistic systems." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI125/document.

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Les réseaux opportunistes sont des réseaux mobiles qui se forment spontanément et de manière dynamique grâce à un ensemble d'utilisateurs itinérants dont le nombre et le déplacement ne sont pas prévisibles. En conséquence, la topologie et la densité de tels réseaux évoluent sans cesse. La diffusion de bout-en-bout d'informations, dans ce contexte, est incertaine du fait de la forte instabilité des liens réseaux point à point entre les utilisateurs. Les travaux qui en ont envisagé l'usage visent pour la plupart des applications impliquant l'envoi de message de petite taille. Cependant, la transmission de données volumineuses telles que les vidéos représente une alternative très pertinente aux réseaux d'infrastructure, en cas d'absence de réseau, de coût important ou pour éviter la censure d'un contenu. La diffusion des informations de grande taille en général et de vidéos en particulier dans des réseaux oppnets constitue un challenge important. En effet, permettre, dans un contexte réseau très incertain et instable, au destinataire d’une vidéo de prendre connaissance au plus vite du contenu de celle-ci, avec la meilleure qualité de lecture possible et en encombrant le moins possible le réseau reste un problème encore très largement ouvert. Dans cette thèse, nous proposons un nouveau mécanisme de diffusion de vidéos dans un réseau opportuniste de faible densité, visant à améliorer le temps d'acheminement de la vidéo tout en réduisant le délai de lecture à destination. La solution proposée se base sur le choix d'encoder la vidéo en utilisant l'encodage SVC, grâce auquel la vidéo se décline en un ensemble de couches interdépendantes (layers), chacune améliorant la précédente soit en terme de résolution, soit en terme de densité, soit en terme de perception visuelle. Notre solution se décline en trois contributions. La première consiste à proposer une adaptation du mécanisme de diffusion Spray-and-Wait, avec comme unités de diffusion, les couches produites par SVC. Les couches sont ainsi diffusées avec un niveau de redondance propre à chacune, adapté à leur degré d'importance dans la diffusion de la vidéo. Notre seconde contribution consiste à améliorer le mécanisme précédent en prenant en compte une granularité plus fine et adaptative en fonction de l'évolution de la topologie du réseau. Cette amélioration a la particularité de ne pas engendrer de coût de partitionnement, les couches vidéos dans l'encodage SVC étant naturellement déclinées en petites unités (NALU) à base desquelles l'unité de transfert sera calculée. Enfin, la troisième contribution de cette thèse consiste à proposer un mécanisme hybride de complétion des couches vidéos arrivées incomplètes à destination. Cette méthode se caractérise par le fait d'être initiée par le destinataire. Elle combine un protocole de demande des parties manquantes aux usagers proches dans le réseau et des techniques de complétion de vidéo à base d’opérations sur les frames constituant la vidéo
Opportunistic networks are human-centric mobile ad-hoc networks, in which neither the topology nor the participating nodes are known in advance. Routing is dynamically planned following the store-carry-and-forward paradigm, which takes advantage of people mobility. This widens the range of communication and supports indirect end-to-end data delivery. But due to individuals’ mobility, OppNets are characterized by frequent communication disruptions and uncertain data delivery. Hence, these networks are mostly used for exchanging small messages like disaster alarms or traffic notifications. Other scenarios that require the exchange of larger data are still challenging due to the characteristics of this kind of networks. However, there are still multimedia sharing scenarios where a user might need switching to an ad-hoc alternative. Examples are the cases of 1) absence of infrastructural networks in far rural areas, 2) high costs due limited data volumes or 3) undesirable censorship by third parties while exchanging sensitive content. Consequently, we target in this thesis a video dissemination scheme in OppNets. For the video delivery problem in the sparse opportunistic networks, we propose a solution that encloses three contributions. The first one is given by granulating the videos at the source node into smaller parts, and associating them with unequal redundancy degrees. This is technically based on using the Scalable Video Coding (SVC), which encodes a video into several layers of unequal importance for viewing the content at different quality levels. Layers are routed using the Spray-and-Wait routing protocol, with different redundancy factors for the different layers depending on their importance degree. In this context as well, a video viewing QoE metric is proposed, which takes the values of the perceived video quality, delivery delay and network overhead into consideration, and on a scalable basis. Second, we take advantage of the small units of the Network Abstraction Layer (NAL), which compose SVC layers. NAL units are packetized together under specific size constraints to optimize granularity. Packets sizes are tuned in an adaptive way, with regard to the dynamic network conditions. Each node is enabled to record a history of environmental information regarding the contacts and forwarding opportunities, and use this history to predict future opportunities and optimize the sizes accordingly. Lastly, the receiver node is pushed into action by reacting to missing data parts in a composite backward loss concealment mechanism. So, the receiver asks first for the missing data from other nodes in the network in the form of request-response. Then, since the transmission is concerned with video content, video frame loss error concealment techniques are also exploited at the receiver side. Consequently, we propose to combine the two techniques in the loss concealment mechanism, which is enabled then to react to missing data parts
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44

Zhao, Yi. "Studies on error control of 3-D zerotree wavelet video streaming." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124811298.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xix, 136 p.; also includes graphics (some col.). Includes bibliographical references (p. 129-136). Available online via OhioLINK's ETD Center
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45

Grimbert, Laurent. "Transmission vidéo MPEG-2 à deux niveaux de priorité sur réseau ATM." Valenciennes, 1998. https://ged.uphf.fr/nuxeo/site/esupversions/53ac8532-1075-48ef-b4f2-ddb3e1de701d.

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La nature variable et aléatoire du trafic vidéo MPEG-2 nécessite le contrôle du débit de chaque source à l'entrée du réseau ATM. Cependant, l'élimination des cellules en excès peut occasionner la perte d'une partie d'image, d'une image complète ou d'un groupe d'images entier dans les cas de pertes d'en-têtes MPEG-2. Pour pallier ce problème, nous proposons dans cette thèse d'utiliser une transmission vidéo à deux niveaux de priorité. Une des originalités de notre étude réside dans le choix des modes de transmission : flux haute priorité sur canal a débit constant (CBR) et flux basse priorité sur canal à débit variable (VBR). Ce système se distingue des autres méthodes (ARQ, FEC,) par sa capacité à garantir la réception des données vidéo de base, sans entrainer une augmentation inacceptable du débit et du délai de transmission, ni perdre de vue l'intérêt majeur de la transmission sur réseau ATM : le multiplexage statistique. L'innovation de ce travail consiste à quantifier les conséquences du choix d'un codage vidéo à deux niveaux de priorité en termes de qualité de service (QOS), d'allocation de ressources, de cout de transmission et de multiplexage statistique. Pour cela, nous avons dans un premier temps étudié une modélisation des flux de cellules sortant des codeurs MPEG-2. Sur la base du processus MMPP(2). Un modèle original, capable de prendre en considération les caractéristiques spatiales du contenu des images ainsi que les différents types d'image du codage MPEG-2 (i, p et b), est propose. L'étude comparative complété des deux modes de codage a deux niveaux de priorité retenus pour ce travail, le DP et le SNR-s, constitue la deuxième originalité de cette thèse. Nous avons pu mettre l'accent sur l'intérêt à transmettre en mode dp plutôt qu'en mode SNR-s, grâce à un flux haute priorité DP de débit plus faible et moins variable, et donc moins couteux. Une comparaison inédite des bandes passantes des codages en mode DP et SNR-s, par rapport au codage monocouche traditionnel, fait apparaitre une légère augmentation du débit total a allouer en transmission a deux niveaux, ce qui correspond au prix a payer en échange de la qualité de service supplémentaire. Nous nous sommes finalement intéressés au cout de transmission a partir de la tarification publiée par un operateur de télécommunications. Outre le fait que la grille de tarifs proposée est inadéquate avec un service vidéo de type grand public, nous nous sommes aperçus de l'inadaptation du rapport des couts du mode CBR sur le mode VBR.
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46

Thie, Johnson Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Optimal erasure protection assignment for scalably compressed data over packet-based networks." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2004. http://handle.unsw.edu.au/1959.4/19373.

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This research is concerned with the reliable delivery of scalable compressed data over lossy communication channels. Recent works proposed several strategies for assigning optimal code redundancies to elements of scalable data, which form a linear structure of dependency, under the assumption that all source elements are encoded onto a common group of network packets. Given large data and small network packets, such schemes require very long channel codes with high computational complexity. In networks with high loss, small packets are more desirable than long packets. The first contribution of this thesis is to propose a strategy for optimally assigning elements of the scalable data to clusters of packets, subject to constraints on packet size and code complexity. Given a packet cluster arrangement, the scheme then assigns optimal code redundancies to the source elements, subject to a constraint on transmission length. Experimental results show that the proposed strategy can outperform the previous code assignment schemes subject to the above-mentioned constraints, particularly at high channel loss rates. Secondly, we modify these schemes to accommodate complex structures of dependency. Source elements are allocated to clusters of packets according to their dependency structure, subject to constraints on packet size and channel codeword length. Given a packet cluster arrangement, the proposed schemes assign optimal code redundancies to the source elements, subject to a constraint on transmission length. Experimental results demonstrate the superiority of the proposed strategies for correctly modelling the dependency structure. The last contribution of this thesis is to propose a scheme for optimizing protection of scalable data where limited retransmission is possible. Previous work assumed that retransmission is not possible. For most real-time or interactive applications, however, retransmission of lost data may be possible up to some limit. In the present work we restrict our attention to streaming sources (e.g., video) where each source element can be transmitted in one or both of two time slots. An optimization algorithm determines the transmission and level of protection for each source element, using information about the success of earlier transmissions. Experimental results confirm the benefit of limited retransmission.
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47

Berro, Mouhammed Jandal [Verfasser], Matthias [Akademischer Betreuer] Reich, Matthias [Gutachter] Reich, Catalin [Gutachter] Teodoriu, and Gerhard [Gutachter] Thonhauser. "Development and testing of alternative methods for speeding up the hydraulic data transmission in deep boreholes / Mouhammed Jandal Berro ; Gutachter: Matthias Reich, Catalin Teodoriu, Gerhard Thonhauser ; Betreuer: Matthias Reich." Freiberg : Technische Universität Bergakademie Freiberg, 2019. http://d-nb.info/1221139347/34.

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48

Yarosh, Svetlana. "Supporting remote synchronous communication between parents and young children." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43680.

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Parents and children increasingly spend time living apart due to marital separation and work travel. I investigated parent--child separation in both of these contexts to find that current technologies frequently do not meet the needs of families. The telephone is easy-to-use and ubiquitous but does not provide an engaging way of communicating with children. Videochat is more emotionally expressive and has a greater potential for engagement but is difficult to set up and cannot be used by a child without the help of an adult. Both telephone and videochat fail to meet the needs of remote parenting because they focus on conversation rather than care and play activities, which are the mechanism by which parents and children build closeness. I also saw that in both types of separation the motivation to connect at times conflicted with desire to reduce disruption of the remote household. To address some of these issues, I designed a system called the ShareTable, which provides easy-to-initiate videochat with a shared tabletop activity space. After an initial lab-based evaluation confirmed the promise of this approach, I deployed the ShareTable to four households (two sets of divorced families). I collected data about the families' remote interactions before and during the deployment. Remote communication more than doubled for each of these families while using the ShareTable and I saw a marked increase in the number of communication sessions initiated by the child. The ShareTable provided benefits over previous communication systems and supported activities that are impossible with other currently available technologies. One of the biggest successes of the system was in providing an overlapped video space that families appropriated to communicate metaphorical touch and a sense of closeness. However, the ShareTable also introduced a new source of conflict for parents and challenged the families as they tried to develop practices of using the system that would be acceptable to all involved. The families' approach to these challenges as well as explicit feedback about the system informs future directions for synchronous communication systems for separated families.
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Witt, Fernando Augusto de. "Desempenho de esquemas ARQ híbrido para transmissão de informação no uplink com transferência de energia no downlink." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1031.

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Investiga-se uma forma de energy harvesting que consiste em recuperar a energia do sinal eletromagnético de rádio frequência (RF), processo que também é conhecido como transferência de energia sem fio. Aplica-se o protocolo time switching (TS) para coordenar o processo de energy harvesting, o qual divide o período de envio de um pacote em dois blocos, o primeiro é dedicado à transferência de energia e o segundo ao envio de informação. A fração do tempo dedicada a cada tarefa, dada pelo parâmetro TS, tem grande impacto no desempenho do sistema. Esta dissertação mostra a investigação do uso do protocolo TS em conjunto com esquemas de retransmissão (HARQ) para o envio da informação. Os resultados mostram que os esquemas HARQ melhoram o desempenho do sistema para a alta relação sinal-ruído (SNR). Essa melhoria é ainda maior quando o destino aplica combinação de Chase entre as diversas cópias do quadro recebido.
We investigate a form of energy harvesting consisting of gathering energy from the radio frequency (RF) electromagnetic waves, also known as wireless power transfer. We employ a time switching (TS) protocol to coordinate the harvesting process, which separates a time slot into two parts, one devoted to wireless energy transfer and the other to wireless information transmission. The fraction of time devoted to each task, the TS parameter, has great impact on the overall performance. This thesis presents an investigation on the usage of the TS protocol, including the numerical optimization of the TS parameter, when hybrid automatic repeat request (HARQ) schemes are used for information transmission. Our results demonstrate that HARQ schemes can improve the system performance for high SNR. This improvement is even better if the destination applies Chase combining among the previously received copies of a frame.
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50

Wertlen, Ronald. "A P2P middleware design for digital access nodes in marginalised rural areas." Thesis, University of Fort Hare, 2010. http://hdl.handle.net/10353/254.

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This thesis addresses software design within the field of Information and Communications Technology for Development (ICTD). Specifically, it makes a case for the design and development of software which is custom-made for the context of marginalised rural areas (MRAs). One of the main aims of any ICTD project is sustainability and such sustainability is particularly difficult in MRAs because of the high costs of projects located there. Most literature on ICTD projects focuses on other factors, such as management, regulations, social and community issues when discussing this issue. Technical matters are often down-played or ignored entirely. This thesis argues that MRAs exhibit unique technical characteristics and that by understanding these characteristics, one can possibly design more cost-effective software. One specific characteristic is described and addressed in this thesis – a characteristic we describe here for the first time and call a network island. Further analysis of the literature generates a picture of a distributed network of access nodes (DANs) within such network islands, which are connected by high speed networks and are able to share resources and stimulate usage of technology by offering a wide range of services. This thesis attempts to design a fitting middleware platform for such a context, which would achieve the following aims: i) allow software developers to create solutions for the context more efficiently (correctly, rapidly); ii) stimulate product managers and business owners to create innovative software products more easily (cost-effectively). A given in the context of this thesis is that the software should use free/libre open source software (FLOSS) – good arguments do also exist for the use of FLOSS. A review of useful FLOSS frameworks is undertaken and several of these are examined in an applied part of the thesis, to see how useful they may be. They form the basis for a walking skeleton implementation of the proposed middleware. The Spring framework is the basis for experiments, along with Spring-Webservices, JMX and PHP 5’s web service capabilities. This thesis builds on three years of work at the Siyakhula Living Lab (SLL), an experimental testbed in a MRA in the Mbashe district of the Eastern Cape of South Africa. Several existing products are deployed at the SLL in the fields of eCommerce, eGovernment and eLearning. Requirements specifications are engineered from a variety of sources, including interviews, mailing lists, the author’s experience as a supervisor at the SLL, and a review of the existing SLL products. Future products are also investigated, as the thesis considers current trends in ICTD. Use cases are also derived and listed. Most of the use cases are concerned with management functions of DANs that can be automated, so that operators of DANs can focus on their core business and not on technology. Using the UML Components methodology, the thesis then proceeds to design a middleware component architecture that is derived from the requirements specification. The process proceeds step-by-step, so that the reader can follow how business rules, operations and interfaces are derived from the use cases. Ultimately, the business rules, interfaces and operations are related to business logic, system interfaces and operations that are situated in specific components. The components in turn are derived from the business information model, that is derived from the business concepts that were initially used to describe the context for the requirements engineering. In this way, a logical method for software design is applied to the problem domain to methodically derive a software design for a middleware solution. The thesis tests the design by considering possible weaknesses in the design. The network aspect is tested by interpolating from formal assumptions about the nature of the context. The data access layer is also identified as a possible bottleneck. We suggest the use of fast indexing methods instead of relational databases to maintain flexibility and efficiency of the data layer. Lessons learned from the exercise are discussed, within the context of the author’s experience in software development teams, as well as in ICTD projects. This synthesis of information leads to warnings about the psychology of middleware development. We note that the ICTD domain is a particularly difficult one with regards to software development as business requirements are not usually clearly formulated and developers do not have the requisite domain knowledge. In conclusion, the core arguments of the thesis are recounted in a bullet form, to lay bare the reasoning behind this work. Novel aspects of the work are also highlighted. They include the description of a network island, and aspects of the DAN middleware requirements engineering and design. Future steps for work based on this thesis are mapped out and open problems relating to this research are touched upon.
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