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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

A system approach to multi-channel acoustic echo cancellation and residual echo suppression for robust hands-free teleconferencing

Wung, Jason 08 June 2015 (has links)
The objective of the research is to achieve a systematic combination of acoustic echo reduction components that together achieve a robust performance of the MCAEC system as a whole. Conventional approaches to the acoustic echo reduction system typically assume that individual components would perform ideally. For example, the adaptive algorithm for AEC is often developed in the absence of strong near-end signal, the algorithm for RES is often an added module that is developed as a separate noise reduction component, and the decorrelation procedure for MCAEC is yet another add-on module that simply introduces some form of distortion to the reference signal. The main challenge is in designing a consistent criterion across all modules that can be jointly optimized to form a more consistent framework for acoustic echo reduction. The decorrelation procedure can potentially benefit from the system approach as well if it is designed by taking the near-end listener into account. The MCAEC system should be optimized not only for the echo cancellation and suppression performance, but also for the reference signal quality after the added distortion from the decorrelation procedure. Finally, a tuning strategy is presented to jointly optimize the parameters across all modules using object criteria.
22

SYSCON 2000 and the DESA Data Relay System

Anderson, Norman 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The Defense Evaluation Support Activity (DESA) is an independent Office of the Secretary of Defense (OSD) activity that provides tailored evaluation support to government organizations. DESA provides quick-response support capabilities and performs activities ranging from studies to large-scale field activities that include deployment, instrumentation, site setup, event execution, analysis and report writing. As the applications of computer systems has dramatically increased in recent year a corresponding increased has ocurred in the data processing needs of test orgznization. One client in particular wanted the realtime ability to track the performance of a country-wide communications system. Commercially developed networking software and hardware were employed to facilitate this requirement. To enhance DESA's off range test support capability a DESA system named SYSCON 2000 has been under steady development for the last five years. In particular the ability to use multiple voice grade telephone lines to create a wideband data channel from almost anywhere has been developed and refined. Link flexibility has been enhanced by the use of dedicated, COTS RF spread-spectrum links, cellular telephones, and other transmission media. The current version of SYSCON 2000 supports test director virtual presence via live data displays and video teleconferencing capability.
23

Information technology in pollution prevention

Choy, Wai-tim, Felix., 蔡偉添. January 2001 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
24

Image motion estimation for 3D model based video conferencing.

January 2000 (has links)
Cheung Man-kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 116-120). / Abstracts in English and Chinese. / Chapter 1) --- Introduction --- p.1 / Chapter 1.1) --- Building of the 3D Wireframe and Facial Model --- p.2 / Chapter 1.2) --- Description of 3D Model Based Video Conferencing --- p.3 / Chapter 1.3) --- Wireframe Model Fitting or Conformation --- p.6 / Chapter 1.4) --- Pose Estimation --- p.8 / Chapter 1.5) --- Facial Motion Estimation and Synthesis --- p.9 / Chapter 1.6) --- Thesis Outline --- p.10 / Chapter 2) --- Wireframe model Fitting --- p.11 / Chapter 2.1) --- Algorithm of WFM Fitting --- p.12 / Chapter 2.1.1) --- Global Deformation --- p.14 / Chapter a) --- Scaling --- p.14 / Chapter b) --- Shifting --- p.15 / Chapter 2.1.2) --- Local Deformation --- p.15 / Chapter a) --- Shifting --- p.16 / Chapter b) --- Scaling --- p.17 / Chapter 2.1.3) --- Fine Updating --- p.17 / Chapter 2.2) --- Steps of Fitting --- p.18 / Chapter 2.3) --- Functions of Different Deformation --- p.18 / Chapter 2.4) --- Experimental Results --- p.19 / Chapter 2.4.1) --- Output wireframe in each step --- p.19 / Chapter 2.4.2) --- Examples of Mis-fitted wireframe with incoming image --- p.22 / Chapter 2.4.3) --- Fitted 3D facial wireframe --- p.23 / Chapter 2.4.4) --- Effect of mis-fitted wireframe after compensation of motion --- p.24 / Chapter 2.5) --- Summary --- p.26 / Chapter 3) --- Epipolar Geometry --- p.27 / Chapter 3.1) --- Pinhole Camera Model and Perspective Projection --- p.28 / Chapter 3.2) --- Concepts in Epipolar Geometry --- p.31 / Chapter 3.2.1) --- Working with normalized image coordinates --- p.33 / Chapter 3.2.2) --- Working with pixel image coordinates --- p.35 / Chapter 3.2.3) --- Summary --- p.37 / Chapter 3.3) --- 8-point Algorithm (Essential and Fundamental Matrix) --- p.38 / Chapter 3.3.1) --- Outline of the 8-point algorithm --- p.38 / Chapter 3.3.2) --- Modification on obtained Fundamental Matrix --- p.39 / Chapter 3.3.3) --- Transformation of Image Coordinates --- p.40 / Chapter a) --- Translation to mean of points --- p.40 / Chapter b) --- Normalizing transformation --- p.41 / Chapter 3.3.4) --- Summary of 8-point algorithm --- p.41 / Chapter 3.4) --- Estimation of Object Position by Decomposition of Essential Matrix --- p.43 / Chapter 3.4.1) --- Algorithm Derivation --- p.43 / Chapter 3.4.2) --- Algorithm Outline --- p.46 / Chapter 3.5) --- Noise Sensitivity --- p.48 / Chapter 3.5.1) --- Rotation vector of model --- p.48 / Chapter 3.5.2) --- The projection of rotated model --- p.49 / Chapter 3.5.3) --- Noisy image --- p.51 / Chapter 3.5.4) --- Summary --- p.51 / Chapter 4) --- Pose Estimation --- p.54 / Chapter 4.1) --- Linear Method --- p.55 / Chapter 4.1.1) --- Theory --- p.55 / Chapter 4.1.2) --- Normalization --- p.57 / Chapter 4.1.3) --- Experimental Results --- p.58 / Chapter a) --- Synthesized image by linear method without normalization --- p.58 / Chapter b) --- Performance between linear method with and without normalization --- p.60 / Chapter c) --- Performance of linear method under quantization noise with different transformation components --- p.62 / Chapter d) --- Performance of normalized case without transformation in z- component --- p.63 / Chapter 4.1.4) --- Summary --- p.64 / Chapter 4.2) --- Two Stage Algorithm --- p.66 / Chapter 4.2.1) --- Introduction --- p.66 / Chapter 4.2.2) --- The Two Stage Algorithm --- p.67 / Chapter a) --- Stage 1 (Iterative Method) --- p.68 / Chapter b) --- Stage 2 ( Non-linear Optimization) --- p.71 / Chapter 4.2.3) --- Summary of the Two Stage Algorithm --- p.72 / Chapter 4.2.4) --- Experimental Results --- p.72 / Chapter 4.2.5) --- Summary --- p.80 / Chapter 5) --- Facial Motion Estimation and Synthesis --- p.81 / Chapter 5.1) --- Facial Expression based on face muscles --- p.83 / Chapter 5.1.1) --- Review of Action Unit Approach --- p.83 / Chapter 5.1.2) --- Distribution of Motion Unit --- p.85 / Chapter 5.1.3) --- Algorithm --- p.89 / Chapter a) --- For Unidirectional Motion Unit --- p.89 / Chapter b) --- For Circular Motion Unit (eyes) --- p.90 / Chapter c) --- For Another Circular Motion Unit (mouth) --- p.90 / Chapter 5.1.4) --- Experimental Results --- p.91 / Chapter 5.1.5) --- Summary --- p.95 / Chapter 5.2) --- Detection of Facial Expression by Muscle-based Approach --- p.96 / Chapter 5.2.1) --- Theory --- p.96 / Chapter 5.2.2) --- Algorithm --- p.97 / Chapter a) --- For Sheet Muscle --- p.97 / Chapter b) --- For Circular Muscle --- p.98 / Chapter c) --- For Mouth Muscle --- p.99 / Chapter 5.2.3) --- Steps of Algorithm --- p.100 / Chapter 5.2.4) --- Experimental Results --- p.101 / Chapter 5.2.5) --- Summary --- p.103 / Chapter 6) --- Conclusion --- p.104 / Chapter 6.1) --- WFM fitting --- p.104 / Chapter 6.2) --- Pose Estimation --- p.105 / Chapter 6.3) --- Facial Estimation and Synthesis --- p.106 / Chapter 6.4) --- Discussion on Future Improvements --- p.107 / Chapter 6.4.1) --- WFM Fitting --- p.107 / Chapter 6.4.2) --- Pose Estimation --- p.109 / Chapter 6.4.3) --- Facial Motion Estimation and Synthesis --- p.110 / Chapter 7) --- Appendix --- p.111 / Chapter 7.1) --- Newton's Method or Newton-Raphson Method --- p.111 / Chapter 7.2) --- H.261 --- p.113 / Chapter 7.3) --- 3D Measurement --- p.114 / Bibliography --- p.116
25

Foreground/background video coding for video conferencing =: 應用於視訊會議之前景/後景視訊編碼. / 應用於視訊會議之前景/後景視訊編碼 / Foreground/background video coding for video conferencing =: Ying yong yu shi xun hui yi zhi qian jing/ hou jing shi xun bian ma. / Ying yong yu shi xun hui yi zhi qian jing/ hou jing shi xun bian ma

January 2002 (has links)
Lee Kar Kin Edwin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 129-134). / Text in English; abstracts in English and Chinese. / Lee Kar Kin Edwin. / Acknowledgement --- p.ii / Abstract --- p.iii / Contents --- p.vii / List of Figures --- p.ix / List of Tables --- p.xiii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- A brief review of transform-based video coding --- p.1 / Chapter 1.2 --- A brief review of content-based video coding --- p.6 / Chapter 1.3 --- Objectives of the research work --- p.9 / Chapter 1.4 --- Thesis outline --- p.12 / Chapter 2 --- Incorporation of DC Coefficient Restoration into Foreground/Background coding --- p.13 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- A review of FB coding in H.263 sequence --- p.15 / Chapter 2.3 --- A review of DCCR --- p.18 / Chapter 2.4 --- DCCRFB coding --- p.23 / Chapter 2.4.1 --- Methodology --- p.23 / Chapter 2.4.2 --- Implementation --- p.24 / Chapter 2.4.3 --- Experimental results --- p.26 / Chapter 2.5 --- The use of block selection scheme in DCCRFB coding --- p.32 / Chapter 2.5.1 --- Introduction --- p.32 / Chapter 2.5.2 --- Experimental results --- p.34 / Chapter 2.6 --- Summary --- p.47 / Chapter 3 --- Chin contour estimation on foreground human faces --- p.48 / Chapter 3.1 --- Introduction --- p.48 / Chapter 3.2 --- Least mean square estimation of chin location --- p.50 / Chapter 3.3 --- Chin contour estimation using chin edge detector and contour modeling --- p.58 / Chapter 3.3.1 --- Face segmentation and facial organ extraction --- p.59 / Chapter 3.3.2 --- Identification of search window --- p.59 / Chapter 3.3.3 --- Edge detection using chin edge detector --- p.60 / Chapter 3.3.4 --- "Determination of C0, C1 and c2" --- p.63 / Chapter 3.3.5 --- Chin contour modeling --- p.67 / Chapter 3.4 --- Experimental results --- p.71 / Chapter 3.5 --- Summary --- p.77 / Chapter 4 --- Wire-frame model deformation and face animation using FAP --- p.78 / Chapter 4.1 --- Introduction --- p.78 / Chapter 4.2 --- Wire-frame face model deformation --- p.79 / Chapter 4.2.1 --- Introduction --- p.79 / Chapter 4.2.2 --- Wire-frame model selection and FDP generation --- p.81 / Chapter 4.2.3 --- Global deformation --- p.85 / Chapter 4.2.4 --- Local deformation --- p.87 / Chapter 4.2.5 --- Experimental results --- p.93 / Chapter 4.3 --- Face animation using FAP --- p.98 / Chapter 4.3.1 --- Introduction and methodology --- p.98 / Chapter 4.3.2 --- Experiments --- p.102 / Chapter 4.4 --- Summary --- p.112 / Chapter 5 --- Conclusions and future developments --- p.113 / Chapter 5.1 --- Contributions and conclusions --- p.113 / Chapter 5.2 --- Future developments --- p.117 / Appendix A H.263 bitstream syntax --- p.122 / Appendix B Excerpt of the FAP specification table [17] --- p.123 / Bibliography --- p.129
26

Intelligent network manager for distributed multimedia conferencing

Al-Jarrah, Mohammad. January 2000 (has links)
Thesis (M.S.)--Ohio University, August, 2000. / Title from PDF t.p.
27

Learning at a distance : the experiences and attributional style of secondary students in an audiographics teleconference chemistry course /

Madore, Kimberly Ann, January 1998 (has links)
Thesis (M. Ed.), Memorial University of Newfoundland, 1998. / Bibliography: leaves [173-181].
28

Only available to a selected few? Is it feasible to rely on a volunteer workforce for complex intervention delivery?

Mountain, Gail, Gossage-Worrall, R., Cattan, M., Bowling, A. 07 October 2015 (has links)
Yes / This paper recounts the process of undertaking a randomised controlled trial which was designed to examine the effectiveness of an intervention for socially isolated older people aged 75 years and over. It describes the reasons for early cessation of the study and raises the implications of this outcome for policy, practice and research. The intervention under investigation was designed to alleviate loneliness and foster companionship. It involves participants being linked with a small group of others through a teleconferencing system with each group being facilitated by trained volunteers. There was a requirement to recruit and train a minimum of 30 and a maximum of 60 volunteers over 1 year to facilitate 20 friendship groups to meet the number of older people required to be recruited to the study. Problems with recruiting and retaining the volunteer workforce by the voluntary sector organisation, who were commissioned to do so, led to the study closing even though older people were recruited in sufficient numbers. The paper draws upon analysis of various data sources from the study to identify the potential reasons. The discussion raises considerations regarding the extent of infrastructure required to deliver community services to vulnerable user groups at scale, identifies some of the issues that need to be addressed if such volunteer-initiated services are to be successful and informs future research programmes in this area. / Public Health Research programme (PHR 09/3004/01). Commissioned by NIHR.
29

Data management in MARRS

Monk, Kitty A January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Computer Science.
30

Teleconferencing and the MARRS computer conferencing system

Stachowicz, Thomas Joseph January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Computer Science.

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