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Nahrstedt, Klara

Overview
Works: 60 works in 121 publications in 2 languages and 1,458 library holdings
Genres: Conference proceedings 
Roles: Author, Editor
Classifications: QA76.575, 006.7
Publication Timeline
Key
Publications about Klara Nahrstedt
Publications by Klara Nahrstedt
Most widely held works by Klara Nahrstedt
Multimedia : computing, communications, and applications by Ralf Steinmetz( Book )
11 editions published between 1995 and 2012 in English and held by 292 libraries worldwide
Multimedia systems by Ralf Steinmetz( Book )
9 editions published between 2004 and 2011 in English and held by 253 libraries worldwide
The goal of Multimedia Systems is to provide a broad understanding of multimedia systems and applications in an integrated manner. A user can enjoy a multimedia application only if all the pieces of the end-to-end solution fit together. This means that a multimedia application must be developed in integrated fashion, taking into account the underlying technology described here. In this volume, we present fundamental characteristics and properties of multimedia operating and communication systems. Of special interest to readers will be those chapters dealing with scheduling algorithms and other OS-supporting approaches for multimedia applications, with their soft-real-time deadlines; multimedia file system internals and servers, with their decision algorithms for data placement and scheduling; multimedia communication, transport, and streaming protocols and services, with their error control, congestion control and other Quality of Service awareness and adaptive algorithms; synchronization services, with their skew control methods; and group communications, with their group coordinating algorithms and other distributed services. Ralf Steinmetz is Professor of Multimedia Communications at the Technische Universität Darmstadt, Germany, and he is chairman of the Board of the Telemedia Center httc.. Together with more than 20 researchers, he is working towards his vision of "truly seamless multimedia communications". He has co-authored over 200 refereed publications, serves as a member of the board of numerous professional committees, is an ICCC Governor, and is a Fellow of both the IEEE and the ACM. Klara Nahrstedt is the Ralph and Catherine Fisher Professor at the department of Computer Science, University of Illinois at Urban-Champagne, USA. She is an expert in the area of multimedia systems and networks and focuses on quality of service management problems. Currently, she serves as the editor-in-chief of the ACM/Springer Multimedia Systems Journal
Multimedia applications by Ralf Steinmetz( Book )
8 editions published between 2004 and 2011 in English and held by 235 libraries worldwide
Multimedia Applications discusses the basic characteristics of multimedia document handling, programming, security, human computer interfaces, and multimedia application services. The overall goal of the book is to provide a broad understanding of multimedia systems and applications in an integrated manner. A user enjoys a multimedia application only if all pieces of the end-to-end solution fit together. This means that a multimedia application and its user interface must be developed in an integrated fashion with underlying multimedia middleware, operating systems, networks, security, and multimedia devices. In this book we will present fundamental information and properties of hypermedia document handling, multimedia security and various aspects of multimedia applications. Especially of interest to the readers will be information about document handling and their standards, programming of multimedia applications, design of multimedia information at human computer interfaces, multimedia security challenges such as encryption and watermarking, multimedia in education, as well as multimedia applications to assist preparation, processing and application of multimedia content. Ralf Steinmetz is Professor of Multimedia Communications at the Technische Universität Darmstadt, Germany, and he is chairman of the Board of the Telemedia Center httc.. Together with more than 20 researchers, he is working towards his vision of "truly seamless multimedia communications". He has co-authored over 200 refereed publications, serves as a member of the board of numerous professional committees, is an ICCC Governor, and is a Fellow of both the IEEE and the ACM. Klara Nahrstedt is the Ralph and Catherine Fisher Professor at the department of Computer Science, University of Illinois at Urban-Champagne, USA. She is an expert in the area of multimedia systems and networks and focuses on quality of service management problems. Currently, she serves as the editor-in-chief of the ACM/Springer Multimedia Systems Journal
Quality of service in wireless networks over unlicensed spectrum by Klara Nahrstedt( file )
6 editions published between 2011 and 2012 in English and Undetermined and held by 169 libraries worldwide
This Synthesis Lecture presents a discussion of Quality of Service (QoS) in wireless networks over unlicensed spectrum. The topic is presented from the point of view of protocols for wireless networks (e.g., 802.11) rather than the physical layer point of view usually discussed for cellular networks in the licensed wireless spectrum. A large number of mobile multimedia wireless applications are being deployed over WiFi (IEEE 802.11) and Bluetooth wireless networks and the number will increase in the future as more phones, tablets, and laptops are equipped with these unlicensed spectrum wireless interfaces. Achieving QoS objectives in wireless networks is challenging due to limited wireless resources, wireless nodes interference, wireless shared media, node mobility, and diverse topologies. The author presents the QoS problem as (1) an optimization problem with different constraints coming from the interference, mobility, and wireless resource constraints and (2) an algorithmic problem with fundamental algorithmic functions within wireless resource management and protocols
Multimedia fundamentals by Ralf Steinmetz( Book )
8 editions published between 2002 and 2011 in English and held by 126 libraries worldwide
Multimedia computing and networking 2000 : 24-26 January, 2000, San Jose, California ( Book )
8 editions published in 2000 in English and held by 111 libraries worldwide
Building QoS into distributed systems : IFIP TC6 WG6.1 Fifth International Workshop on Quality of Service (IWQOS '97), 21-23 May 1997, New York, USA by IFIP TC6 WG6.1 International Workshop on Quality of Service( Book )
6 editions published in 1997 in English and held by 64 libraries worldwide
This volume contains the Fifth International Workshop, Quality of Service, sponsored by the International Federation for Information Processing (IFIP), and held in May 1997, Columbia University New York USA. This book is essential reading for engineers and R&D students, and for researchers in multimedia networking areas
Multimedia fundamentals by Ralf Steinmetz( file )
in English and held by 53 libraries worldwide
Media coding and content processing by Ralf Steinmetz( Book )
4 editions published in 2002 in English and held by 33 libraries worldwide
Proceedings of the second International Conference on Internet Multimedia Computing and Service by International Conference on Internet Multimedia Computing and Service( file )
1 edition published in 2010 in English and held by 11 libraries worldwide
Multimedia fundamentals by Ralf Steinmetz( Book )
7 editions published in 2002 in English and held by 10 libraries worldwide
Multimedia fundamentals, Volume 1 by Ralf Steinmetz( file )
1 edition published in 2002 in English and held by 9 libraries worldwide
End-to-end QoS guarantees : lessons learned from OMEGA by Klara Nahrstedt( Book )
1 edition published in 1996 in English and held by 8 libraries worldwide
A tuning system for distributed multimedia applications by Klara Nahrstedt( Book )
1 edition published in 1996 in English and held by 8 libraries worldwide
A soft real time scheduling server in UNIX operating system by Hao-hua Chu( Book )
1 edition published in 1997 in English and held by 7 libraries worldwide
Duo mei ti ji shu ( Book )
2 editions published between 1997 and 2000 in Chinese and held by 3 libraries worldwide
Building QoS into distributed systems ( Book )
1 edition published in 1997 in English and held by 3 libraries worldwide
Multimedia and security : workshop at ACM Multimedia '99, Orlando, Florida, USA, October 30 - November 5, 1999 ( Book )
1 edition published in 1999 in English and held by 3 libraries worldwide
Panorama: a multimedia happening ( visu )
2 editions published in 2008 in English and held by 3 libraries worldwide
Live dance juxtaposed with large - and small-scale projections using robotic cameras and tele-immersion and audio technologies. At the center of Panorama are 22 dancers, including UC Berkeley students and members of the dance theater company Smith/Wymore Disappearing Acts. They perform choreographed movement -- including excerpts from Merce Cunningham's work -- plus movement structures co-authored by computers through a series of alogrithms with recited text derived from computational models
Design and evaluation of real-time Voice-Over-IP (VOIP) systems with high perceptual conversational quality by Batu Sat( Computer File )
1 edition published in 2010 in English and held by 2 libraries worldwide
This research addresses real-time multimedia communication systems that can achieve high perceptual quality for their users. It focuses on the fundamental understanding of multiple quality aspects perceived and their trade-offs in the design of run-time control schemes that adapt to changing network conditions and expectations of the users of a system. One of the main contributions of this thesis is the use of adaptively scheduled off-line subjective comparison tests to efficiently and accurately learn users' subjective preferences among the alternative trade-offs in order to guide the run-time control schemes to achieve high perceptual quality. In order to illustrate the application of the general framework and our methodology, throughout this thesis we study the design of real-time VoIP (voice-over-IP) systems that can achieve high perceptual conversational quality. The trade-offs in the design and operation of a VoIP system involve the design of speech codecs and strategies for network control, playout scheduling, and loss concealment. The perceptual quality of a conversation over a network connection depends on the quality of the one-way speech (listening-only speech quality or LOSQ) received and the delay incurred from the mouth of the speaker to the ear of the listener (mouth to ear delay or MED). In a conversation, each participant takes turns in speaking and listening, and both perceive a silence duration called mutual silence (MS) when the conversation switches from one party to another. When the connection has delays, the MSs perceived by a participant consist of alternating short and long silence periods between turns. As a result, listeners may experience lower perceptual quality when the MSs are highly asymmetric, some speakers appearing to be more distant than others, or some responding slower than others. The evaluation of conversational quality is a largely unexplored area. There are many objective metrics for assessing the quality of a VoIP conversation, but there is no single objective metric whose results match well with subjective results. Indiscriminate subjective testing is not feasible because it is prohibitively expensive to carry out many such tests under various conversational and network conditions. Moreover, there is no systematic method to generalize the subjective test results to unseen conditions. To this end, there are five key innovations in this research that will address the limitations of existing work and improve the perceptual quality of VoIP systems. Firstly, we have developed a methodology and test-bed to objectively and subjectively evaluate VoIP systems under repeatable and fair conditions using a black-box approach. We have applied this methodology and test-bed on four commonly used VoIP systems; Skype, Google-Talk, Windows Live and Yahoo Messenger. The results show that different systems operate differently in coping with network imperfections such as jitter and loss. We also observe that systems do not change their operation as a function of the one-way delay of the connection, or of the turn-taking frequency of the conversation. The results show thatWindows Live is preferred under a significant set of conditions but none of the systems is dominant under all conditions. We have also learned the mapping between easily obtainable objective measures and subjective preferences of users in order to allow any VoIP system to be comprehensively compared against others without expensive subjective comparisons. We later use the mapping learned to subjectively compare our newly designed system with the four systems already evaluated. Secondly, we have developed a general model of pair-wise subjective comparisons, based on individually identified properties, axioms and lemmas, that models comparisons on a continuous operating curve with a single control parameter. The model provides a basis for developing the method to schedule adaptive off-line subjective tests and for identifying the optimal point by fusing the information obtained from separate subjective evaluations on the same operating curve. The model can be used in formulating and solving any type of pair-wise comparison problem that exhibits the same properties identified. The model is flexible to allow the existence of multiple optimal points on an operating curve and includes a belief function framework that can guide the search for optimal points efficiently. Furthermore, the model is built on a statistical framework that allows for the confidence of individual evaluation results to be represented in the conclusiveness of the combined belief function. Thirdly, we have developed a method for tackling the control design problem of finding the optimal point in an N-dimensional space, which includes all the metrics that affect quality. The overall problem is transformed into two independent problems of finding the optimal point on a continuous but one-dimensional curve, and learning the mapping on a set of curves that adequately spans the K-dimensional (K < N) curve space, where K stands for the number of metrics characterizing the network and conversational conditions. Fourthly, we have applied the methodology to the design of play-out scheduling control for VoIP systems by conducting subjective tests and by learning from them under a comprehensive set of network and conversational conditions. We have also verified the accuracy and efficiency of our methodology using exhaustive subjective tests on a subset of the network and conversational conditions. The verification of our methodology on a real-life application also justified our model of pair-wise subjective comparisons and our optimal algorithm to adaptively choose upcoming comparisons using information learned from previously conducted tests. Lastly, we have generalized the learned results in the design of play-out scheduling control to conditions that are unseen at design time and observed only at run-time. Along with design choices in other components of the architecture, this results in a VoIP system that can achieve higher and more consistent perceptual quality than other four VoIP systems analyzed. We have also shown that our system performs very close to a non-causal ideal system where the POS decisions are made optimally using future information. Our model and methodologies are applicable to a wide variety of real-time multimedia communication system control design problems which operate under constrained resources, communicating over non-stationary IP networks, and for which the overall quality perceived by users of the system has multiple counteracting aspects which cannot be represented by a single objective metric
 
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English (78)
Chinese (2)
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