检索结果-内蒙古大学图书馆

Binarized cross-approximate entropy in crowdsensing environment

COMPUTERS IN BIOLOGY AND MEDICINE 2017年 80卷 137-147页

作者： Skoric, Tamara Mohamoud, Omer Milovanovic, Branislav Japundzic-Zigon, Nina Bajic, Dragana Univ Novi Sad Fac Tech Sci Ctr Excellence CEVAS Trg Dositeja Obradov 6 Novi Sad 21000 Serbia Univ Belgrade Sch Med Lab Cardiovasc Pharmacol Belgrade 11001 Serbia Bezanijska Kosa Hosp Neurocardiol Dept Belgrade 11000 Serbia

Objectives: Personalised monitoring in health applications has been recognised as part of the mobile crowdsensing concept, where subjects equipped with sensors extract information and share them for personal or common benefit. Limited transmission resources impose the use of local analyses methodology, but this approach is incompatible with analytical tools that require stationary and artefact-free data. This paper proposes a computationally efficient binarised cross-approximate entropy, referred to as (X)BinEn, for unsupervised cardiovascular signal processing in environments where energy and processor resources are limited. Methods: The proposed method is a descendant of the cross-approximate entropy ((X)ApEn). It operates on binary, differentially encoded data series split into m-sized vectors. The Hamming distance is used as a distance measure, while a search for similarities is performed on the vector sets. The procedure is tested on rats under shaker and restraint stress, and compared to the existing (X)ApEn results. Results: The number of processing operations is reduced. (X)BinEn captures entropy changes in a similar manner to (X)ApEn. The coding coarseness yields an adverse effect of reduced sensitivity, but it attenuates parameter inconsistency and binary bias. A special case of (X)BinEn is equivalent to Shannon's entropy. A binary conditional entropy for m =1 vectors is embedded into the (X)BinEn procedure. Conclusion: (X)BinEn can be applied to a single time series as an auto-entropy method, or to a pair of time series, as a cross-entropy method. Its low processing requirements makes it suitable for mobile, battery operated, self-attached sensing devices, with limited power and processor resources.

关键词： Cross-approximate entropy Conditional entropy differential coding Crowdsensing Cardiovascular signals

来源：评论

学校读者我要写书评

暂无评论

Error Probability Analysis for Time-Varying Chaos Unitary Matrix-Based differential MIMO System

引用

IEEE WIRELESS COMMUNICATIONS LETTERS 2022年第7期11卷 1399-1403页

作者： Zhai, Xiaodan Song, Guochao Xiao, Lixia Liu, Guanghua Ishikawa, Naoki Jiang, Tao Huazhong Univ Sci & Technol Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Res Ctr 6G Mobile Commun Wuhan 430074 Peoples R China China Acad Informat & Commun Technol Mobile Commun Innovat Ctr Beijing 100191 Peoples R China Huazhong Univ Sci & Technol Sch Cyber Sci & Engn Wuhan 430074 Peoples R China Yokohama Natl Univ Fac Engn Yokohama Kanagawa 2408501 Japan

The time-varying (TV) chaos unitary matrix based differential multiple-input multiple-output (D-MIMO) system is capable of achieving beneficial performance gains without channel state information (CSI). To elaborate a little further, the chaos sequence is embedded into the data-carrying matrices by a unique time-varying matrix. By employing differential coding during two adjacent signal blocks, a non-coherent detector can be developed without CSI knowledge. However, its theoretical performance analysis becomes challenging due to its complex construction. To address this issue, the theoretical average bit error probability (ABEP) lower and upper bounds of the TV-D-MIMO system are analyzed using the moment generating function (MGF) over generalized fading channel. The experimental results are shown that the derived ABEP upper and lower bounds are tight with the simulation results, which is helpful for future performance evaluation.

关键词： Chaos Fading channels Time-varying systems MIMO communication Error probability Encoding Indexes Multiple-input multiple-output time-varying chaos unitary matrix differential coding chaos sequence average bit error probability

来源：评论

学校读者我要写书评

暂无评论

Interpixel Interference Mitigation in Visible Light Communication Using Image Sensor

引用

IEEE ACCESS 2018年 6卷 45543-45551页

作者： Dat Vuong Yoo, Myungsik Soongsil Univ Sch Elect Engn Seoul 06978 South Korea

To improve the data rate in a camera-based visible light communication system, multiple LEDs in an LED array are used to transmit multiple bits in one frame. The problem is that LEDs are always captured in the image with some degree of blooming effect. This effect increases the intensity of pixels surrounding the origin LEDs in the image. When multiple LEDs are used, the blooming effect from all LEDs causes the interpixel interference (IPI) problem that greatly degrades the quality of the received signal. This paper analyzes the blooming effect and finds that the IPI problem increases when the number of "ON" LEDs in the array increases. Through the analysis, this paper proposes a differential coding to minimize the number of "ON" LEDs in every transmitted frame and thus minimize the IPI effect. The proposed scheme is then verified through simulations. The results show that a lower bit error rate, which indicates a better signal quality, can be achieved by applying the proposed scheme.

关键词： VLC LED image sensor differential coding interference

来源：评论

学校读者我要写书评

暂无评论

CHAIN CODES AND THEIR LINEAR RECONSTRUCTION FILTERS

引用

IEEE TRANSACTIONS ON INFORMATION THEORY 1992年第2期38卷 268-280页

作者： WONG, PW KOPLOWITZ, J Department of Electrical and Computer Engineering Clarkson University Potsdam NY USA

A differential chain code implementation of the basic 8-directional and N-ring chain code for the encoding of line drawings is considered. Several distortion and rate criteria are considered, and they are evaluated for the special case of encoding infinite straight lines. These results indicate that (he differential code outperforms ring codes and the ring delta code. Linear decoding filters for reconstructing a smoothed approximation to the original line are also considered. Optimal reconstruction filters for infinite straight lines at various angles are considered. An angle invariant reconstruction filter that minimizes the expected square distortion taken over all angles is also derived. The overall performance using this filter is close to that of the optimum filter. Furthermore, the impulse response of the angle invariant filter is approximately rectangular, which can lead to simple hardware implementations.

关键词： CHAIN CODE differential coding LINE DRAWINGS OPTIMUM RECONSTRUCTION FILTER SMOOTHING FILTER QUANTIZATION ERROR

来源：评论

学校读者我要写书评

暂无评论

differential distributed space-time modulation for cooperative networks

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2006年第11期5卷 3097-3108页

作者： Wang, Genyuan Zhang, Yimin Amin, Moeness Villanova Univ Ctr Adv Commun Villanova PA 19085 USA

In this paper, we develop a protocol for the construction of cooperative networks when the channel state information is not available at the transmitters and the receivers. In the proposed protocol, differential space-time codewords are generated at the source terminal. In the broadcast phase, each row of the differential space-time codeword is transmitted to a different relay, whereas in the relay phase, the relaying terminals retransmit the codeword through simple amplify-and-forward algorithm. The performance of the cooperative diversity system is analyzed for a two-user case for different channel environments in terms of the diversity gain and the diversity product. The optimization of the power allocation between source and relay terminals is considered for the maximization of the diversity product. When the same modulation scheme is used, the performance of differential detection is degraded by 3 dB noise enhancement compared with coherent detection.

关键词： cooperative diversity MIMO space-time coding differential coding

来源：评论

学校读者我要写书评

暂无评论

Efficient reference frame compression scheme for video coding systems: algorithm and VLSI design

引用

JOURNAL OF REAL-TIME IMAGE PROCESSING 2019年第2期16卷 391-411页

作者： Silveira, Dieison Povala, Guilherme Amaral, Livia Zatt, Bruno Agostini, Luciano Porto, Marcelo Fed Univ Pelotas UFPel Grp Architectures & Integrated Circuits GACI Pelotas RS Brazil Fed Univ Rio Grande do Sul UFRGS Inst Informat Porto Alegre RS Brazil

One of the most concerning issues in current video coding systems relies on the bottleneck caused by the intense external memory access required by motion estimation. As memory access affects directly the energy consumption, this problem becomes more evident when battery-powered devices are considered. In this sense, this article presents the Double differential Reference Frame Compressor (DDRFC), which is a low-complexity and lossless solution to compress the reference frames before storing them in the external memory. The DDRFC performs intra-block double differential coding over 64 x 64-sample blocks to prepare the data for a static Huffman coding. The DDRFC guarantees block-level random access by avoiding data dependencies between neighboring blocks. It reaches an average compression ratio of 69% for luminance samples for 1080 p video sequences, outperforming any lossless reference frame compressor available in the current literature. Hardware architectures for both the DDRFC encoder and decoder were designed and synthesized targeting FPGA and ASIC 180 and 65-nm standard cells libraries. The synthesis results show that with 65 nm, the DDRFC architectures are able to process 2160 p video at 30 FPS or 1080 p at 120 FPS with a power dissipation of 5.01 mW. The DDRFC codec reaches more than 68% of energy savings when considering memory communication for HD and UHD video processing.

关键词： Video coding HEVC Lossless reference frame compression Memory bandwidth reduction Hardware design differential coding Huffman coding

来源：评论

学校读者我要写书评

暂无评论

differential space time media-based modulation system

引用

IET COMMUNICATIONS 2022年第9期16卷 942-950页

作者： Zou, Hongliang Quan, Daying Jin, Xiaoping Zhou, Yueru China Jiliang Univ Coll Informat Engn Hangzhou Peoples R China

differential spatial modulation (DSM) is a multi-antenna differential technology with low power consumption and no demand of channel estimation. It is suitable for communication systems that have fast migration velocity and high requirements for both power consumption and complexity. However, due to the sparse structure and the requirements of differential coding, the spectral efficiency is limited. Therefore, media-based modulation (MBM) technology is introduced into differential system in this work to improve the spectral. A differential space time media-based modulation (DSTMBM) system is proposed. While retaining the inherent advantages of the DSM, the additional bits are transmitted through the radio frequency (RF) mirrors in DSTMBM. Unlike traditional DSM, the transmit antenna of DSTMBM system can be activated multiple times. In addition, a theoretical performance is derived, and a low-complexity (LC) detection algorithm is adopted. Simulation results show that the DSTMBM system has a performance advantage of about 4.5 dB at a high transmission rate compared to traditional DSM systems. Monte Carlo simulation matches the theoretical performance in a wide range. Meanwhile, the LC detection algorithm reduces the complexity by 2-3 orders of magnitude without the bit error rate (BER) performance loss.

关键词： Monte Carlo methods theoretical performance low-complexity detection algorithm communication systems differential technology low power consumption differential spatial modulation media-based modulation technology transmit antenna transmitting antennas channel estimation differential space time media-based modulation system differential system fast migration velocity error statistics modulation DSTMBM system traditional DSM systems differential coding

来源：评论

学校读者我要写书评

暂无评论

High-Speed Single-Ended Parallel Link Based on Three-Level differential Encoding

引用

IEEE JOURNAL OF SOLID-STATE CIRCUITS 2009年第2期44卷 549-557页

作者： Zogopoulos, Sotirios Namgoong, Won NetLog Microsyst Inc Mountain View CA 94043 USA Univ Texas Dallas Richardson TX 75080 USA

An encoding scheme for high-speed single-ended parallel transceiver system is presented. Compared to the 50% I/O pin utilization of the conventional differential encoding, the proposed system employs 3-level differential coding to increase the utilization to 75% and 93% using a group of four and six conductors, respectively. The proposed coding scheme also reduces the effects of inter-symbol interference (ISI), removes reference ambiguity, and reduces power line fluctuations at the transmitter side. Using simple encoder/decoder, the proposed scheme enables multiple drivers at the transmitter to recycle the same current, reducing power consumption. To validate the proposed system, a parallel link was designed in 0.18 mu m CMOS process. The chip implements the coding algorithm over four conductors and achieves a data rate of 4.2 Gb/s/pin while dissipating 17.1 mW/Gb/s.

关键词： Data transmission differential coding fast intercommunications low power parallel link receiver serial link single ended transceiver transmitter

来源：评论

学校读者我要写书评

暂无评论

Concatenated convolutional and differential codes in interference-suppressed DS-CDMA systems

引用

IEE PROCEEDINGS-COMMUNICATIONS 2002年第2期149卷 99-104页

作者： Li, Y Li, KH Natl Univ Singapore Ctr Wireless Commun Singapore 117674 Singapore Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

A serial concatenated convolutional and differential coding scheme is employed in a multi-user direct-sequence code-division multiple-access (DS-CDMA) system. The system consists of single-user detectors (SUDs), which are used to suppress multiple-access interference (MAI) with no requirement of other users' spreading codes, timing, or phase information. The differential code, treated as a convolutional code of code rate I and memory 1, does not sacrifice the coding efficiency and has the least number of states. The iterative process exchanges information between the differential decoder and the convolutional decoder. Both component decoders adopt the a posteriori probability (APP) algorithm. Numerical results in additive white Gaussian noise (AWGN) channels show that this concatenated coding scheme provides better performance and more flexibility than conventional convolutional codes in DS-CDMA systems, even in the sense of similar complexity. Further study shows that the performance of this coding scheme applied to DS-CDMA systems with SUDs improves by increasing the processing gain or the number of taps of the interference suppression filter. and degrades for higher near-far interfering power or additional near-far interfering users.

关键词： Direct-sequence code-division multiple access Rejection filters AWGN Codes code rate CDMA mobile communications decoders labeling scheme WATER FAUCETS Iterative Process convolutional coding differential coding

来源：评论

学校读者我要写书评

暂无评论

An acquisition scheme for communications in multi-antenna sensor networks with low signal to noise ratio

引用

INTERNATIONAL JOURNAL OF SENSOR NETWORKS 2018年第4期27卷 259-267页

作者： Aldunate, Joaquin Oberli, Christian Pontificia Univ Catolica Chile Dept Elect Engn Vicuna Mackenna 4860 Santiago 7820436 Chile

Recent results show that multiple antenna communications can improve the energy efficiency of wireless communications. These techniques are thus attractive for use in wireless sensor networks. In particular, diversity techniques can be used to improve the acquisition of wireless links, especially for low signal-to-noise ratio (SNR) situations. This paper presents an acquisition scheme well suited for wireless sensor networks such as low-power wide-area networks (LPWAN) with multiple antenna sensor nodes. The scheme exploits a differentially encoded preamble and receive diversity in order to detect signals at very low SNR without requiring channel state information. We show that it achieves a better trade-off between the probability of acquisition false alarm and failed acquisition than single-antenna communications. Therefore, it enables networks with larger node separation at given transmission power, such as in LPWANs. The scheme's performance is thoroughly analysed theoretically and verified by simulations.

关键词： multi-antenna wireless sensor networks acquisition scheme LPWAN low-power wide-area networks low signal to noise ratio preamble sequence diversity differential coding channel state information signal detection

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：