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Asymmetric binary tree coding for contour images

IMAGE AND VISION COMPUTING 2003年第9期21卷 797-807页

作者： Shamim, A Robinson, JA Mem Univ Newfoundland Fac Engn & Appl Sci St Johns NF A1B 3X5 Canada

We consider the coding of featured contours, i.e. texture, object or motion boundaries in images. The MPEG-4 and MPEG-7 video coding standards provide for a content-based representation of video information, so efficient coding of boundaries can play an important role. We propose a new coding scheme that uses an asymmetric binary tree. We show that the new scheme outperforms conventional quadtree, binary tree, contour and READ coding algorithms applied to typical boundary images and also offers competitive performance for general-purpose two-level image coding. (C) 2003 Elsevier B.V. All rights reserved.

关键词： hierarchical coding contour coding

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Cooperative multicasting based on superposition and layered coding

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IET COMMUNICATIONS 2014年第3期8卷 267-277页

作者： Elgendi, Mohamed Nasr, Omar A. Khairy, Mohamed M. Cairo Univ Fac Engn Ctr Wireless Studies Giza 12211 Egypt

Cooperative diversity plays an important role in combating channel fading and increasing reliability of wireless communication links. The main purpose of cooperative diversity is to transmit the same data from multiple sources. Hence, there is no inherent capability in the cooperative diversity schemes to deal with scalable types of data, for example, scalable video coded signals. The authors introduce a two-phase cooperative multicast scheme based on superposition coding to transmit scalable video signals. The new scheme mixes the superposition with cooperative diversity, and chooses the right parameters in both schemes to enhance the system's multicast capability. This study also derives an exact closed-form expression of the average multicast group throughput in case of Rayleigh flat fading channel. The closed-form expression allows system designers to choose the correct cooperation and superposition parameters to satisfy the network operator needs. Simulations show that, in addition to the additional degrees of freedom resulting from using cooperation with superposition, the proposed scheme outperforms the conservative scheme and schemes solely exploiting cooperative relaying or superposition. Simulations show that the new scheme can increase the average network throughput more than four times compared to the conservative scheme.

关键词： Closed-form solutions Scheme multicast communication SUPERPOSITION Degree of freedom hierarchical coding superposition coding Network operators Multicast CARRIER SYSTEM scalable video

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ONIONCODE: Enabling Multi-priority coding in LED-based Optical Camera Communications 41

ONIONCODE: Enabling Multi-priority Coding in LED-based Optic...

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41st IEEE Conference on Computer Communications (IEEE INFOCOM)

作者： Wu, Haonan Chen, Yi-Chao Xue, Guangtao Jiang, Yuehu Wang, Ming Qian, Shiyou Yu, Jiadi Chen, Pai-Yen Shanghai Jiao Tong Univ Dept Comp Sci & Engn Shanghai Peoples R China Univ Illinois Dept Math Champaign IL USA Univ Illinois Dept Elect & Comp Engn Chicago IL USA

ISBN: (纸本)9781665458221

Optical camera communication (OCC) has attracted increasing attention recently thanks to the wide usage of LED and high-resolution cameras. The lens-image sensor structure enables the camera distinguish light from various source, which is ideal for spatial MIMO. Hence, OCC can be applied to several emerging application scenarios, such as vehicle and drone communications. However, distance is a major bottleneck for OCC system, because the increase in distance makes it difficult for the camera to distinguish adjacent LEDs, which we call LED spatial mixing. In this paper, we propose a novel hierarchical coding scheme named as ONIONCODE to support dynamic range of channel capacity in one-to-many OCC scenario. ONIONCODE adopts a multi-priority receiving scheme, i.e., the receivers can dynamically discard the low-priority bit streams according to the measured channel capacity. ONIONCODE achieves this based on a key insight that, the luminance level of a mix-LED is distinguishable. We prototype a LED-based OCC system to evaluate the efficacy of ONIONCODE and the results show that ONIONCODE achieves a higher coding efficiency and overall throughput compared with the existing hierarchical coding.

关键词： optical camera communications hierarchical coding one-to-many transmission

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The multiple-access channel with partial state information at the encoders

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IEEE TRANSACTIONS ON INFORMATION THEORY 2005年第11期51卷 3992-4003页

作者： Cemal, Y Steinberg, Y AudioCodes Ltd IL-70151 Airport City Lod Israel Technion Israel Inst Technol Dept Elect Engn IL-32000 Haifa Israel

This work studies the multiple-access channel (MAC) controlled by random parameters, with full side information at the decoder, and partial, rate limited, side information (SI) at the encoders. A single-letter characterization of the capacity region is derived, for the special case where the SI is degraded. Here degraded SI refers to the case where the SI available at one of the encoders is a subset of the SI available at the other encoder. Inner and outer bounds are derived on the capacity region of that channel for the general case where there are no restrictions on the structure of the SI at the two encoders. The techniques employed for coding the rate-limited SI, and the achievable regions so obtained, are closely related to the problems of hierarchical source coding, and multiple descriptions.

关键词： hierarchical coding multiple-access channel (MAC) multiple description side information (SI) state-controlled channels succesive refinement

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Light Field Image Compression Using Generative Adversarial Network-Based View Synthesis

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IEEE JOURNAL ON EMERGING AND SELECTED TOPICS IN CIRCUITS AND SYSTEMS 2019年第1期9卷 177-189页

作者： Jia, Chuanmin Zhang, Xinfeng Wang, Shanshe Wang, Shiqi Ma, Siwei Peking Univ Inst Digital Media Beijing 100871 Peoples R China Univ Southern Calif Ming Hsieh Dept Elect Engn Los Angeles CA 90089 USA City Univ Hong Kong Dept Comp Sci Hong Kong Peoples R China

Light field (LF) has become an attractive representation of immersive multimedia content for simultaneously capturing both the spatial and angular information of the light rays. In this paper, we present a LF image compression framework driven by a generative adversarial network (GAN)-based sub-aperture image (SAI) generation and a cascaded hierarchical coding structure. Specifically, we sparsely sample the SAIs in LF and propose the GAN of LF (LF-GAN) to generate the unsampled SAIs by analogy with adversarial learning conditioned on its surrounding contexts. In particular, the LF-GAN learns to interpret both the angular and spatial context of the LF structure and, meanwhile, generates intermediate hypothesis for the unsampled SAIs in a certain position. Subsequently, the sampled SAIs and the residues of the generated-unsampled SAIs are re-organized as pseudo-sequences and compressed by standard video codecs. Finally, the hierarchical coding structure is adopted for the sampled SAI to effectively remove the inter-view redundancies. During the training process of IF-GAN, the pixel-wise Euclidean loss and the adversarial lass are chosen as the optimization objective, such that sharp textures with less blurring in details can be produced. Extensive experimental results show that the proposed LF-GAN-based LF image compression framework outperforms the state-of-the-art learning-based IF image compression approach with on average 4.9% BD-rate reductions over multiple LF datasets.

关键词： Light field image compression SAI synthesis adversarial learning hierarchical coding

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Automatic Transition Prediction in Hybrid Flow Solver, Part 2: Practical Application

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JOURNAL OF AIRCRAFT 2009年第4期46卷 1191-1199页

作者： Krumbein, Andreas Krimmelbein, Normann Schrauf, Geza German Aerosp Ctr DLR Inst Aerodynam & Flow Technol C2A2S2E D-37073 Gottingen Germany Braunschweig Univ Technol Inst Fluid Mech Aerodynam Aircraft D-38106 Braunschweig Germany Airbus Germany Aerodynam Domain D-28199 Bremen Germany

This article is the second of two companion papers which document the concept and the application of a coupled computational fluid dynamics system which, was designed to incorporate the prediction of laminar-turbulent transition into a hybrid Reynolds-averaged Navier-Stokes solver. Whereas the first part deals with the description of the transition prediction methodology and the sensitivities of the coupled system, the second part documents its practical application. The complete coupled system consists of the Reynolds-averaged Navier-Stokes code, a laminar boundary-layer code, and a fully automated Local, linear stability code. The system predicts and applies transition locations due to Tollmien-Schlichting and crossflow instabilities using the e(N) method based on the two-N-factor approach. The coupled system was designed to be applied to three-dimensional aircraft configurations which are of industrial relevance. The application of the coupled system to a wing-body configuration with a three-element wing consisting of slat, main wing, and flap is described and documented in this paper. The prediction of the laminar-turbulent transition lines was done in a fully automatic manner. It is shown that complex aircraft configurations can be handled without a priori knowledge of the transition characteristics of the specific flow problem.

关键词： main wings transition location coupled system hierarchical coding Codes aircraft aerodynamic configuration

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hierarchical Coded Matrix Multiplication

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IEEE TRANSACTIONS ON INFORMATION THEORY 2021年第2期67卷 726-754页

作者： Kianidehkordi, Shahrzad Ferdinand, Nuwan Draper, Stark C. Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada Huawei Technol Canada Co Ltd Ottawa ON K2K 3J1 Canada

In distributed computing systems slow working nodes, known as stragglers, can greatly extend finishing times. Coded computing is a technique that enables straggler-resistant computation. Most coded computing techniques presented to date provide robustness by ensuring that the time to finish depends only on a set of the fastest nodes. However, while stragglers do compute less work than non-stragglers, in real-world commercial cloud computing systems (e.g., Amazon's Elastic Compute Cloud (EC2)) the distinction is often a soft one. In this paper, we develop hierarchical coded computing that exploits the work completed by all nodes, both fast and slow, automatically integrating the potential contribution of each. We first present a conceptual framework to represent the division of work amongst nodes in coded matrix multiplication as a cuboid partitioning problem. This framework allows us to unify existing methods and motivates new techniques. We then develop three methods of hierarchical coded computing that we term bit-interleaved coded computation (BICC), multilevel coded computation (MLCC), and hybrid hierarchical coded computation (HHCC). In this paradigm, each worker is tasked with completing a sequence (a hierarchy) of ordered subtasks. The sequence of subtasks, and the complexity of each, is designed so that partial work completed by stragglers can be used, rather than ignored. We note that our methods can be used in conjunction with any coded computing method. We illustrate this by showing how we can use our methods to accelerate all previously developed coded computing techniques by enabling them to exploit stragglers. Under a widely studied statistical model of completion time, our approach realizes a 66% improvement in the expected finishing time. On Amazon EC2, the gain was 27% when stragglers are simulated.

关键词： Encoding Task analysis Acceleration Computational modeling Interleaved codes Error correction codes Visualization Distributed system coded computing stragglers hierarchical coding partial computation

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Low-Complexity Multi-Stream Space-Time Codes-Part I: Direct-Sum Codes and Design Criteria

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IEEE TRANSACTIONS ON COMMUNICATIONS 2012年第1期60卷 81-88页

作者： Stauffer, Erik Hochwald, Bertrand Broadcom Corp Sunnyvale CA 94086 USA Univ Notre Dame Dept Elect Engn Notre Dame IN 46556 USA

Multi-stream codes are used in wireless broadcast services where two or more priority classes of data are transmitted simultaneously, and a receiving terminal may decode one or more of the streams as a function of its receive signal to noise ratio. Present-day commercial cellular-based broadcast services generally utilize hierarchical modulation, a clever technique for embedding high and low-priority streams in a single modulated quadrature symbol. With many cellular standards moving to multiple-transmit antenna configurations, there are opportunities for designing new multi-stream encoding techniques that exploit these antennas. We examine the design of space-time codes that allow simple encoding and decoding of high and low-priority streams of data. A desirable multi-stream space-time code has a combination of good performance and low complexity. Performance is generally measured as coded bit-error rate, assuming max-log maximum aposteriori decoding. Complexity is measured as the effort needed to compute the aposteriori probabilities for either stream. hierarchical modulation, for single-antenna transmissions, allows each stream to be decoded simply and independently. The paper comprises two parts. In this first part, we establish a general performance criterion for two-stream space-time codes and derive a formula for the complexity of max-log maximum aposteriori decoding of either stream. We also show how existing space-time codes may be combined with hierarchical modulation in a "direct sum". The direct-sum codes have low complexity, but we show in the second part of this paper that these codes can be significantly outperformed by non-direct-sum codes. One of our proposed two-stream codes performs 4 dB better than the Alamouti direct-sum code;it also has the benefit of decoding complexity in one stream that is a bounded function of the rate of the other.

关键词： Space-time coding broadcast hierarchical coding multi-stream

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A scalable three bit-rates 8-14.1-24 kbit/s audio coder

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ANNALES DES TELECOMMUNICATIONS-ANNALS OF TELECOMMUNICATIONS 2000年第9-10期55卷 483-492页

作者： Taddei, H Massaloux, D Le Guyader, A France Telecom R&D DIH DIPS F-22307 Lannion France

This paper presents a scalable three bit-rates (8, 14.1 and 24 il kbit/s) coder: For the two embedded lowest ones, operating in the telephone bandwidth, CELP coding techniques are used. For the highest rate, that both improves narrowband quality and extends the band to [50-7000Hz], transform coding techniques are used. The main applications deal with transmission over network,with no guaranteed QoS.

关键词： speech coding sound coding coder decoder scalability hierarchical coding passband compression sound quality

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A lossless image compression for medical images based on hierarchical sorting technique

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2002年第1期E85D卷 108-114页

作者： Myojoyama, A Yamamoto, T Hokkaido Univ Grad Sch Engn Sapporo Hokkaido 0608628 Japan

We propose new lossless medical image compression method based on hierarchical sorting technique. hierarchical sorting is a technique to achieve high compression ratio by detecting the regions where image pattern varies abruptly and sorting pixel order by its value to increase predictability. In this method, we can control sorting accuracy along with size and complexity. As the result, we can reduce the sizes of the permutation-tables and rouse the tables to other image regions. Comparison using experimental implementation of this method shows better performance for medical image set measured by X-ray CT and MRI instruments where similar sub-block patterns appear frequently. This technique applies quad-tree division method to divide an image to blocks in order to support progressive decoding and fast preview of large images.

关键词： lossless compression medical images sorting algorithm hierarchical coding

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