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International Journal of Digital Content technology and its Applications 2012年第19期6卷 145-151页

作者： Zhang, Deng-Yin Wen, Jun Wang, Zhou-Yang Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

In order to ensure the visual quality and the objective quality of video under low bandwidth, this paper presents a FGS enhancement layer coding algorithm for interested region. First, this paper introduces the traditional FGS enhancement layer coding and analyzes the exist problems. Then, proposes the main steps and description of the FGS enhancement layer coding algorithm for interested region. Finally, this paper shows the effectiveness of the algorithm through experimental results.

关键词： Codes (symbols)

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Object detection by clustering-based nonparametric kernel density estimation

Object detection by clustering-based nonparametric kernel de...

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作者： Hu, D. Hu, J. Education Ministry's Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications China Jiangsu Province's Key Lab of Image Procession and Image Communications Nanjing University of Posts and Telecommunications China

ISBN: (纸本)9781845648282

Nonparametric model is one of the popular ones for background modeling for its ability to adapt to changes quickly in dynamic environment and enable very sensitive detection of moving objects. However, the method is too complex and computationally inefficient to real-time application. In this paper, a fast and efficient scheme for moving object detection by nonparametric background modeling was proposed, whereas the background was modeled combining clustering theory to eliminate the large amount of redundant information and noise pixels in background modeling stage. Moreover, adaptive background and temporal differencing was used to filter out unchanged background pixels, thus enabling an additional reduction in computational requirements and improving the detection results. Besides, RGB color components were substituted by chromaticity coordinates to suppress shadow effects. Experimental results demonstrated the effectiveness of the proposed algorithm. © 2014 WIT Press.

关键词： Object detection

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Outage performance analysis in cognitive wireless relay networks

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Research Journal of Applied Sciences, Engineering and technology 2012年第20期4卷 3958-3964页

作者： Yue, Wenjing Chen, Zhi Wang, Anyi Hu, Luoquan Wang, Lei Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunication Nanjng China

The analysis the outage performance of suggested Cognitive Wireless Relay network (CWRN) which consists of a source, a destination and M cognitive relay nodes and M primary user nodes. In this study, we mainly study that the cognitive relay nodes impact on the outage performance of proposed CWRN over Rayleigh channels under both the peak and average interference power constraints. Firstly, considering a scenario with a single cognitive relay node, the optimal power control policies of the cognitive relay nodes are derived in order to achieve the minimum system outage probability under different interference power constraints. Then, to further improve outage performance, a scenario with multi-relay is also studied. Finally, the numerical simulations are presented. Numerical results show that substantial performance improves with the increase of the number of cognitive relay nodes and the power control policy under the average interference power constraint is more effective than that under the peak interference power constraint. © Maxwell Scientific Organization, 2012.

关键词： Cognitive radio

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Accurate and fast DV-hop localization algorithm in irregular networks 5th

Accurate and fast DV-hop localization algorithm in irregular...

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5th International Conference on Artificial Intelligence and Security, ICAIS 2019

作者： Yan, Xiaoyong Feng, Xiang Sun, Zhixin Broadband Wireless Communication and Sensor Network Technology Key Lab of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing210003 China YuanTong Express Co. LTD. Shanghai201705 China

ISBN: (纸本)9783030242701

The DV-hop localization algorithm does not depend on any measurement hardware, which only uses hop-counts to describe the Euclidean distance between nodes, it will not generate any additional burden, and thus this lightweight localization algorithm is economical and effective. Unfortunately, nodes generally have irregular distribution in reality, which tends to make deviations during the conversion between hop-counts and Euclidean distance, and as a result, the final estimated locations of nodes tend to deviate from the right location. Therefore, we analyzed the error during the hop-counts and Euclidean distance conversion, derived that the variance of error is related to hop-counts, and used the weighted least square method to correct the deviation. On this basis, we also limit the estimation location range of normal nodes according to the distances relationship between the estimated distances of normal nodes to anchor nodes and the distances of normal nodes estimated location to anchor nodes. Both the theoretical analysis and experimental results show that the proposed algorithm has not only maintained the economic characteristics of DV-hop localization, but also has the high localization accuracy and it can be adapted to various networks with different deployment of nodes. © Springer Nature Switzerland AG 2019.

关键词： Location

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Preparation of biomedical Ag incorporated hydroxyapatite/titania coatings on Ti6Al4V alloy by plasma electrolytic oxidation

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Chinese Physics B 2014年第3期23卷 427-434页

作者：周澜吕国华毛菲菲杨思泽 College of Mathematics & Physics Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Institute of Physics Chinese Academy of Sciences Department of Oral and Maxillofacial Surgery Interdisciplinary LaboratoryPeking University School of Stomatology Fujian Key Laboratory for Plasma and Magnetic Resonance Department of AeronauticsSchool of Physics and Mechanical & Electrical Engineering Xiamen University

Nano-Ag incorporated hydroxyapatite/titania （HA/TiO2） coatings were deposited on Ti6A14V substrates by the plasma electrolytic oxidation process. Compared with the substrate, the deposited coatings display attractive mechani- cal and biomedical properties. First, the coatings have stronger wear resistance and corrosion resistance. Second, they show a strong antibacterial ability. The mean vitality of the P. gingivalis on the coating surfaces is reduced to about 21%. Third, the coatings have good biocompatibility. The mean viability of the fibroblast cells on the coating surface is increased to about 130%. With these attractive properties, Ag incorporated HA/TiO2 coatings may be useful in the biomedical field.

关键词： hydroxyapatite corrosion resistance antibacterial ability biocompatibility

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Properties of focused Laguerre–Gaussian beam propagating in anisotropic ocean turbulence

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Chinese Physics B 2024年第2期33卷 386-393页

作者：王新光马洋斌袁邱杰陈伟王乐赵生妹 College of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel *** the Rytov approximation theory,we derive the analytical formula of the channel capacity of the focused LG beam in the anisotropic ocean turbulence,and analyze the relationship between the capacity and the light source parameters as well as the turbulent ocean *** is found that the focusing mirror can greatly enhance the channel capacity of the system at the geometric focal plane in oceanic *** results also demonstrate that the communication link can obtain high channel capacity by adopting longer beam wavelength,greater initial beam waist radius,and larger number of transmission ***,the capacity of the system increases with the decrease of the mean squared temperature dissipation rate,temperature-salinity contribution ratio and turbulence outer scale factor,and with the increase of the kinetic energy dissipation rate per unit mass of fluid,turbulence inner scale factor and anisotropy *** to a Hankel–Bessel beam with diffraction-free characteristics and unfocused LG beam,the focused LG beam shows superior anti-turbulence interference properties,which provide a theoretical reference for research and development of underwater optical communication links using focused LG beams.

关键词： vortex beam orbital angular momentum focusing mirror anisotropic turbulence

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Compressive fault-tolerance network coding

Compressive fault-tolerance network coding

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2013 IEEE International Conference on Signal Processing, communications and Computing, ICSPCC 2013

作者： Chen, Siguang Wu, Meng Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781479910274

Because many signals are correlated over temporal domain, this paper proposes a compressive fault telorance network coding scheme for exploring the temporal correlation of signals. This scheme overcomes the drawbacks of network coding theory by injecting the compressed sensing theory into network coding, i.e., the scheme possesses well compression gain. Meanwhile, it can tolerate finite errors and reconstruct the original information with low distortion when the rank of error matrix (induced by errors) is lying in a reasonable bound. Finally, the performance analysis shows that the compressed sensing-based network coding scheme outperforms the conventional network coding scheme with significant improvement in robustness and performance. © 2013 IEEE.

关键词： Fault tolerance

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NLOS Error Mitigation in Mobile Location Based on Modified Extended Kalman Filter

NLOS Error Mitigation in Mobile Location Based on Modified E...

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IEEE Wireless communications and networking Conference (WCNC)

作者： Zhou, Xin Jin, A-Long Meng, Qingmin Key Lab. of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Southeast University Nanjing China National Mobile Communications Research Lab. Southeast University Nanjing China Nanjing University of Posts and Telecommunications Nanjing 210003 China

ISBN: (纸本)9781467304375;9781467304368

Geolocation and tracking of mobile objects is an important issue in wireless communication networks. Various methods have been devised and implemented to deal with such problems whose performance is particularly limited in non-line-of-sight propagation conditions. In this paper, we take advantage of the extended Kalman filter with some extensions, modifications and improvement of previous work to reduce the NLOS error in the location measurement. One of the key contributions of this paper is to present the methods that discriminate the NLOS measurements from the LOS measurements based on the standard deviation and K-means clustering and reconstruct the LOS measurements out of the NLOS measurements by polynomial fit in order to mitigate the NLOS error. Simulation results confirm the effectiveness and accuracy of our approach in comparison with the conventional EKF algorithm. Moreover, we do not model the distribution of the NLOS error due to its intractability.

关键词： Non-Line-of-Sight Extended Kalman filter K-means clustering LOS reconstruction polynomial fit

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Delay constraint adaptive routing based on seed spray in opportunistic networks

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Journal of Computational Information Systems 2012年第12期8卷 5137-5148页

作者： Xu, Jia Wang, Ruchuan Sun, Lijuan College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210003 China Key Lab. of Broadband Wireless Communication and Sensor Network Technol. Min. of Edu. Jiangsu Prov. Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Laboratory for Computer Network and Information Integration Ministry of Education Southeast University Nanjing 211189 China State Key Lab. for Novel Software Technology Nanjing University Nanjing 210093 China

Opportunistic networks are sparse wireless networks which have no complete path from the source to the destination most of the time. Many applications require the support of delay constrained routing mechanism which can provide acceptable and resilient services in the challenged environments. We proposed Adaptive Seed Spray (ASS) to achieve the delay constraint with low cost in dynamic opportunistic networks. ASS will estimate the routing cost in source node, and use a small number of seed nodes to spray message copies in order to reduce redundant copies. Furthermore, ASS will make spray decisions in relay nodes which have the latest information of the networking conditions. Simulation results have shown that ASS has prominent superiority in routing cost and adaptability, and it is an efficient delay-bounded multi-copy routing protocol for opportunistic networks especially for dynamic conditions. © 2012 Binary Information Press.

关键词： Cost benefit analysis

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QoS-based data aggregation technology in wireless sensor networks

QoS-based data aggregation technology in wireless sensor net...

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2011 WASE Global Conference on Science Engineering, GCSE 2011

作者： Chen, Zhengyu Yang, Geng Li, Guohua Xu, Jian Key Lab. of Broadband Wireless Communication and Sensor Network Technology Ministry of Education College of Computer Science and Technology Nanjing University of Post and Telecommunications Nanjing 210046 China School of Information Technology Jinling Institute of Technology Nanjing 211169 China

ISBN: (纸本)9783037852903

The main goal of data-aggregation algorithms in wireless sensor networks (WSNs) is to gather and aggregate data in an energy efficient manner so that network lifetime is enhanced. In this article, we focus on QoS-based data-aggregation problems in WSNs. Firstly, we provide a definition of the different QoS parameters for data aggregation, such as energy efficiency, network lifetime, data latency and data quality. Then, we compare the different algorithms on each QoS parameter, describe the main features of each algorithm, and highlight the trade-offs between each parameter. Finally, we conclude with possible future research directions on QoS-based data aggregation in WSNs.

关键词： Wireless sensor networks

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