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Optical Transmission, Switching, and Subsystems VI

作者： Chang, Qingjiang Huang, Mingfang Su, Yikai State Key Lab. of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China School of Electrical and Computer Engineering Georgia Institute of Technology GA 30332 United States

We propose that double broadcast services can be overlaid over high-speed point-to-point downlink data in a WDM-PON with source-free optical network units (ONUs). In the optical line terminal (OLT), a set of single-drive MachZehnder modulators (MZMs) are driven by downlink point-to-point data to generate a differential phase-shift keying (DPSK) format. The downlink DPSK signals from different wavelengths are multiplexed and then fed to a following dual-parallel MZM (DPMZM) as a double broadcast services transmitter. The broadcast service-l is an optical carrier suppression (OCS) format, while the broadcast service-2 is an inverse return-to-zero (IRZ) forma. After the transmission, at each ONU, the optical signals are separated by an optical filter. The filtered OCS signal is detected to retrieve the broadcast service-1. The DPSK/IRZ signals are split into three parts, one part is detected by an IRZ receiver to recover the broadcast service-2, the second part is detected by a DPSK receiver to retrieve the downlink data and the third part is re-modulated by the upstream amplitude shift keying (ASK). We also perform an experiment to verify the feasibility of the proposed scheme, where the power penalties of less than 1.5 dB are obtained after 25-km transmission with 1.25-Gb/s data rate. © 2008 SPIE.

关键词： Digital storage

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New design of chirped mirrors for femtosecond pulse compression

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Guangxue Xuebao/Acta Optica Sinica 2008年第SUPPL.期28卷 89-91页

作者： Wang, Xi Chen, Lingling Yang, Weijian Zhang, Zhigang State Key Laboratory of Advanced Optical Communication System and Networks School of Electronics Engineering and Computer Science Peking University Beijing 100871 China Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

A novel technique of optimizing chirped mirrors is proposed. Simulation demonstrates that the residual group delay dispersion ripples of two matched chirped mirrors is less than 10 fs2 over the wavelength range of 700-1050 nm and that of three matched chirped mirrors is less than 15 fs2 over the same range. These kinds of chirped mirrors have precisely controlled group delay dispersion, which plays a critical role in the generation of ultrashort pulses and compression of few-cycle to monocycle femtosecond pulses.

关键词： Group delay

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Distributed and Optimal Congestion Control for Application-Layer Multicast: A Synchronous Dual Algorithm

Distributed and Optimal Congestion Control for Application-L...

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Consumer communications and Networking Conference, CCNC IEEE

作者： Jinyao Yan Martin May Bernhard Plattner Computer and Network Center Communication University of China Beijing China Computer Engineering and Networks Laboratory Swiss Federal Institute of Technology ETH Zurich Switzerland

In this paper, we study the topic of distributed and optimal congestion control for scalable video streams in application-layer multicast (ALM). We propose a TCP-friendly, fully distributed synchronous algorithm based on the utility-price model which maximizes the global utilities for the streams in the application-layer multicast tree. With the help of numerical study, we show that our proposed algorithm optimizes the overall video quality for fine-grained scalable streams, while minimizing the messaging overhead in the application-layer multicast channel.

关键词： Optimal control Multicast algorithms Streaming media Multicast protocols Unicast communication system control computer networks Distributed computing Distributed control Algorithm design and analysis

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Scheduling Algorithms for Simultaneous Software Updates of Electronic Devices in Vehicles

Scheduling Algorithms for Simultaneous Software Updates of E...

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IEEE International Conference on communications Workshops, ICC

作者： J. Sommer V. Feil E. A. Sanz Institute of Communication Networks and Computer Engineering (IKR) University of Stuttgart Stuttgart Germany Infotainment and Telematics Daimler Benz Aerospace Sindelfingen Germany

Today's upper-class passenger cars have various interconnected electronic devices. Each device performs complex functions, enabled by software that can be stored in a flash memory. Of these, the devices in the multimedia and infotainment domain contain by far the most software with a size in the order of one Gbyte. In this domain, the devices are the performance bottlenecks, not the communication systems. Throughout the vehicle life cycle, parts of the software have to be frequently updated during maintenance. Today, the software of the devices is updated in a consecutive manner. Due to performance bottlenecks caused by the affected devices, the update can take a long time that leads to high costs. Therefore, the objective is to reduce the total update time by a higher utilization of the common bus resource. In this paper, we introduce and investigate algorithms that update the software of multiple devices simultaneously and evaluate the efficiency of these algorithms. We focus on scheduling algorithms on the Application layer and the logical link control (LLC) layer and model the update process by means of Petri nets. Our studies show that it is most promising to combine a simple scheduling algorithm on the Application layer with Round Robin on the LLC layer.

关键词： Scheduling algorithm Vehicles Software algorithms Round robin Software performance Flash memory Software maintenance Costs Application software Petri nets

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Multi-modal multi-user telepresence and teleaction system

Multi-modal multi-user telepresence and teleaction system

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2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS

作者： Buss, Martin Peer, Angelika Schauß, Thomas Stefanov, Nikolay Unterhinninghofen, Ulrich Behrendt, Stephan Färber, Georg Leupold, Jan Diepold, Klaus Keyrouz, Fakheredine Sarkis, Michel Hinterseer, Peter Steinbach, Eckehard Färber, Berthold Pongrac, Helena Institute of Automatic Control Engineering Technische Universität München Munich Germany Institute for Real-Time Computer Systems Technische Universität München Munich Germany Institute for Data Processing Technische Universität München Munich Germany Institute of Communication Networks Technische Universität München Munich Germany Human Factors Institute University of the Bundeswehr Munich Germany

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Traffic Modelling with Stochastic Lindenmayer Systems

Traffic Modelling with Stochastic Lindenmayer Systems

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ITG-Fachtagung, Photonische Netze

作者： Detlef Sass University of Stuttgart Institute of Communication Networks and Computer Engineering (IKR)

ISBN: (纸本)9783800730971

Traffic characteristics in communication systems have changed massively in the past. However, these changes are ongoing as this is a continuous process caused by constantly changing technologies, services and usage patterns. Simultaneously, research enabled a refined understanding of traffic characteristics. An important and traffic invariant characteristic is self-similarity and long range dependence. This is also present in the Internet backbone, impacting particularly performance evaluation studies due to its significantly slower decrease of correlations/variability. Therefore, it essential that traffic models reflect the relevant characteristics of real traffic appearing in current networks and provide additional flexibility for further changes. Lindenmayer System (L-System) based traffic models provide such a flexibility. In this paper, we extend the L-System model to the bit-rate level. We show the good modelling properties of the extended L-System model on basis of artificial traces and real traces of a broad-band user access rate scenario. We describe the developed modifications of the fitting process to accommodate the model extension.

关键词： Barium

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Reversible Watermarking Schemes Using Spatial Quad-Based Difference Expansion

Reversible Watermarking Schemes Using Spatial Quad-Based Dif...

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International Conference on Hybrid Information Technology, ICHIT

作者： Zhiguo Chang Jian Xu Weidong Kou Department of Communication Engineering Xi''an Institute of Posts and Telecommunications Xi'an China State Key Laboratory of Integrated Service Networks Xidian University Xi'an China Department of Computer Science & Engineering Shanghai Jiaotong University Shanghai China

In this paper, we make use the fact that the differences between the pixel values in the local region of an image are small and propose two simple and effective reversible watermarking schemes based on the spatial quad-based difference expansion that applies the difference expansion to the image in row-wise and column-wise simultaneously. The schemes make good use of both row-wise and column-wise pixel pairs with small differences. Experimental results show our schemes are effective.

关键词： Watermarking Pixel PSNR Image coding Image processing Artificial neural networks Transforms

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Ultra broadband SOI binary blazed grating mirror

Ultra broadband SOI binary blazed grating mirror

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IEEE International Conference on Group IV Photonics

作者： Huaming Wu Yi Wang Junbo Feng Yao Chen Jin Hou Dingshan Gao Zhiping Zhou Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan Hubei China Laboratory on Advanced Optical Communication Systems and Networks Peking University Beijing China School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

A novel SOI grating mirror based on thin binary blazed grating layer is presented. The binary blazed grating mirror (BBGM) has the characteristics of ultra broadband reflection spectrum, high reflectivity and large an... 详细信息

ISBN: (纸本)9781424417698

关键词： Gratings Mirrors Reflectivity Optimized production technology Broadband communication Reflection System-on-a-chip

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Low loss sharp bend for silicon nanophotonic slow-light waveguide

Low loss sharp bend for silicon nanophotonic slow-light wave...

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IEEE International Conference on Group IV Photonics

作者： Huaxiang Yi Yi Wang Junbo Feng Yao Chen Zhiping Zhou Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan Hubei China State Key Laboratory on Advanced Optical Communication Systems and Networks Peking University Beijing China School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

A low loss sharp bend is proposed and analyzed in the slow-light waveguide which is consisted of a series of silicon nanopillars. More than 90% of transmission over 100 nm bandwidth is obtained.

ISBN: (纸本)9781424417698

A low loss sharp bend is proposed and analyzed in the slow-light waveguide which is consisted of a series of silicon nanopillars. More than 90% of transmission over 100 nm bandwidth is obtained.

关键词： Optical waveguides Silicon Optical buffering Optical resonators Dispersion Optical losses Optical coupling

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Audio-Visual Speech Processing Framework for Lip Reading

Audio-Visual Speech Processing Framework for Lip Reading

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International Conference on Information and communication Technologies: From Theory to Applications, ICTTA

作者： Abdulbaset M. Nasr Abd Rahman Ramli Mohammad Hamiruce Shamala K Subramaniam Robotics Lab Institute of advanced technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Computer and Communications Systems Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Electrical and Electronics Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia Department of Communication Technology & Networks Faculty of Computer Science and Information Technology Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia

It is well known that speech production and perception process is inherently bimodal consisting of audio and visual components. Recently there has been increased interest in using the visual modality in combination with the acoustic modality for improved speech processing. This field of study has gained the title of audio-visual speech processing. Lip movement recognition, also known as lip reading, is a communication skill which involves the interpretation of lip movements in order to estimate some important parameters of the lips that include, but not limited to, size, shape and orientation. In this paper, we represent a hybrid framework for lip reading which is based on both audio and visual speech parameters extracted from a video stream of isolated spoken words. The proposed algorithm is self-tuned in the sense that it starts with an estimations of speech parameters based on visual lip features and then the coefficients of the algorithm are fine-tuned based on the extracted audio parameters. In the audio speech processing part, extracted audio features are used to generate a vector containing information of the speech phonemes. These information are used later to enhance the recognition and matching process. For lip feature extraction, we use a modified version of the method used by F. Huang and T. Chen for tracking of multiple faces. This method is based on statistical color modeling and the deformable template. The experiments based on the proposed framework showed interesting results in recognition of isolated words.

关键词： Speech processing Image processing Parameter estimation Data mining Feature extraction Robots computer networks Systems engineering and theory communications technology computer science

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