检索结果-内蒙古大学图书馆

Minimum-Energy Broadcast Trees in All-Wireless Networks

电子学报(英文版) 2008年第2期17卷 227-230页

作者： HU Tian ZHAO Baohua Department of Computer Science University of Science and Technology of China Anhui Province Key Laboratory of Software in Computing and Communication Hefei 230027 China

This paper focuses on the problem of constructing the minimum-energy broadcast trees in all-wireless networks. We proposed a greedy algorithm called Greedy maximum-branch replacement algorithm (GMBR) to decrease the total power of the broadcast tree further. This algorithm can be developed to a distributed one easily. Compared with the previous algorithms, GMBR was proved to have better performance, especially when the propagation loss exponent and the network size become larger.

关键词：最小能量广播天线网络技术性能

来源：评论

学校读者我要写书评

暂无评论

A Simple Single-Fed Penta-Band Omnidirectional Antenna with Independent Band Control

引用

IEEE Transactions on Antennas and Propagation 2025年

作者： Zhou, Changfei Gao, Tianyu Zhang, Ruyue Yu, Dapeng Zhang, Wenyu Li, Yingsong Wong, Hang Dalian University of Technology School of Information and Communication Engineering Dalian116024 China Hubei University of Automotive Technology School of Mathematics Physics and Optoelectronic Engineering Shiyan China Anhui University Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Hefei230601 China City University of Hong Kong The State Key Laboratory of Terahertz and Millimeter Waves Hong Kong

A novel method of designing a penta-band omnidirectional low-profile antenna with independent band control is proposed. Single-band, dual-band, tri-band, quad-band, and penta-band antennas are investigated, respectively. The proposed penta-band antenna consists of a circular patch, three concentric metal pins, and two square metal plates. The evolutionary step of the penta-band antenna is achieved by adding metal rings and a small metal plate above the big ground. Each of the four metal rings is excited at TM01 mode resonance, while the 5th mode is generated by a small loop resonance formed by the small plate, shorting pin, stub, and the outer conductor of the cable. The penta-band antenna has a small volume of π × (0.109λ1.53GHz)2 × 0.053λ1.53GHz. The corresponding impedance bandwidths (IMBWs) of the five operating bands are 4.9%, 9.4%, 9.0%, 4.8%, 5.0%. Compared with other designs, the proposed antennas exhibit more flexible bands by using a simple structure. Meanwhile, the antenna has a stable omnidirectional radiation pattern across the five bands and a compact size. © 1963-2012 IEEE.

关键词： Monopole antennas

来源：评论

学校读者我要写书评

暂无评论

Both non-uniform mixing states and coating structures are important for the absorption enhancement and radiative effect of black carbon

引用

Optics Express 2025年第10期33卷 21719-21735页

作者： Jie Luo Wenlong Wang Qibing Qiu Qixing Zhang Congcong Li Weizhen Hou Xudong Dong Miao Hu College of Communication Engineering Hangzhou Dianzi University Hangzhou Zhejiang China National Institute of Natural Hazards Ministry of Emergency Management of China Beijng China wenlongwang@*** Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China State Key Laboratory of Fire Science University of Science and Technology of China Hefei Anhui China Zhejiang Academy of Emergency Management Science and Technology Hangzhou Zhejiang China State Environment Protection Key Laboratory of Satellite Remote Sensing Aerospace Information Research Institute Chinese Academy of Sciences Beijing China miao_hu@***

Black carbon absorption is a major contributor to global warming, with considerable uncertainty due to complex microscopic properties. Previous studies have mainly attributed the complex absorption enhancement (E abs ) to the non-uniform mixing states, while the effects of the non-uniform coating structure have usually been ignored. In this paper, a modeling framework was proposed to simultaneously investigate the effects of complex coating structures and mixing states. At the particle scale, the effects of non-uniform coating structure can generally be reflected by three levels, and we show that modeling the non-uniform coating structure is important to explain the small E abs observed in laboratory measurements, which are difficult to explain with a Mie-based model and a model of uniform coating structure. On a population scale, the simultaneous consideration of heterogeneous mixing states and coating structures can significantly improve the model performance in reproducing the field measurements. Although both non-uniform mixing states and coating structures have an important impact on the global aerosol optical absorption depth (AAOD) and direct radiative forcing (DRF), they may attenuate each other’s effects. Therefore, previous studies may overestimate the effects of mixing states based on Mie theory by assuming a uniform coating structure. This work clearly demonstrates the importance of both non-uniform mixing conditions and coating structure on aerosol absorption and DRF.

关键词： Absorption coefficient Atmospheric absorption Mie scattering Near infrared Optical absorption Optical properties

来源：评论

学校读者我要写书评

暂无评论

NewBalance: Efficient Data Space Management and Algorithmic Optimization for Large-Scale Storage Systems

引用

Chinese Journal of Electronics 2017年第3期26卷 493-501页

作者： XU Guangping LIN Sheng SHI Kai ZHANG Hua Tianjin Key Laboratory of Intelligence Computing and New Software Technology Computer and Communication Engineering School Tianjin University of Technology

Fragmentation usually occurs when data space of original storage nodes has to be reallocated to new added storage nodes during the scale-out evolution of the large-scale storage *** greatly influences its performance and becomes a challenge to manage the whole *** present an efficient space management framework,called New Balance,to reduce fragmentation with the minimum data movement while keeping the storage system load *** space management framework has two phases including the collection phase and the allocation *** the collection phase,we propose a novel algorithm,called the greedy bi-direction collector,which collects enough space for the new storage *** the allocation phase,we formally represent it as a variant of the bin packing problem and then utilize some bin packing heuristics including the first fitting and the best fitting to allocate collected intervals to new added storage *** experimental results show that the amount of intervals can be reduced by 20%;5%and our algorithmic optimization improves the data lookup performance by at least 10%and the scale-out performance by 2X;X.

关键词： Large-scale storage systems Space management Algorithmic optimization Performance evaluation

来源：评论

学校读者我要写书评

暂无评论

Classifying and clustering in negative databases

引用

Frontiers of Computer Science 2013年第6期7卷 864-874页

作者： Ran LIU Wenjian LUO Lihua YUE School of Computer Science and Technology University of Science and Technology of China Hefei 230027 China Anhui Province Key Laboratory of Software Engineering in Computing and Communication University of Science and Technology of China Hefei 230027 China

Recently, negative databases （NDBs） are proposed for privacy protection. Similar to the traditional databases, some basic operations could be conducted over the NDBs, such as select, intersection, update, delete and so on. However, both classifying and clustering in negative databases have not yet been studied. Therefore, two algorithms, i.e., a k nearest neighbor （kNN） classification algorithm and a k-means clustering algorithm in NDBs, are proposed in this paper, respectively. The core of these two algorithms is a novel method for estimating the Hamming distance between a binary string and an NDB. Experimental results demonstrate that classifying and clustering in NDBs are promising.

关键词： negative databases classification clustering k nearest neighbor k-means hamming distance

来源：评论

学校读者我要写书评

暂无评论

Secure Two-Party Point-Circle Inclusion Problem

引用

Journal of Computer Science & Technology 2007年第1期22卷 88-91页

作者：罗永龙黄刘生仲红 Department of Computer Science University of Science and Technology of China Hefei 230027 China Department of Computer Science Anhui Normal University Wuhu 241000 China Anhui Province Key laboratory of Software in Computing and Communication Hefei 230027 China

Privacy-preserving computational geometry is a special secure multi-party computation and has many applications. Previous protocols for determining whether a point is inside a circle are not secure enough. We present a two-round protocol for computing the distance between two private points and develop a more efficient protocol for the point-circle inclusion problem based on the distance protocol. In comparison with previous solutions, our protocol not only is more secure but also reduces the number of communication rounds and the number of modular multiplications significantly.

关键词： secure multi-party computation computational geometry homomorphic encryption scheme private comparison

来源：评论

学校读者我要写书评

暂无评论

Performance of CO-OFDM system with RS-Turbo concatenated code

引用

Optoelectronics Letters 2015年第6期11卷 457-460页

作者：童峥嵘胡桂彬曹晔张卫华 Key Laboratory of Film Electronics and Communication Devices and Key Laboratory of Intelligent Computing and Novel Software Technology Tianjin University of Technology

In this paper,the RS-Turbo concatenated code is applied to coherent optical orthogonal frequency division multiplexing(CO-OFDM) ***(186,166,8) and Turbo code with code rate of 1/2 are employed for RS-Turbo concatenated *** decoding algorithms,which are Max-Log-MAP algorithm and Log-MAP algorithm,are adopted for Turbo decoding,and the iteration Berlekamp-Massey(BM) algorithm is adopted for RS *** simulation results show that the bit error rate(BER) performance of CO-OFDM system with RS-Turbo concatenated code is significantly improved at high optical signal to noise ratio(OSNR),and the iteration number is reduced compared with that of the Turbo coded ***,when the Max-Log-MAP algorithm is adopted for Turbo decoding,the transmission distance of CO-OFDM system with RS-Turbo concatenated code can reach about 400 km without error,while that of the Turbo coded system can only reach about 240 km when BER is lower than 10^(-4) order of magnitude.

关键词： OFDM系统 RS解码 Max-Log-MAP算法性能 Turbo码正交频分复用解码算法光信噪比

来源：评论

学校读者我要写书评

暂无评论

Research on the transmission performance of turbo codes in DDO-OFDM system

引用

Optoelectronics Letters 2015年第2期11卷 134-136页

A direct detection optical orthogonal frequency division multiplexing(DDO-OFDM)system using turbo codes is built,and the transmission performance comparison between coded system and uncoded system is *** decoding algorithms,which are Log-maximum a posteriori(MAP),Max-Log-MAP and threshold Max-Log-MAP,are used in the turbo coded *** comparing three decoding algorithms,the system using Max-Log-MAP algorithm has the best bit error rate(BER)*** the transmission distance of 240 km,the uncoded system with transmission rate of 30 Gbit/s can get the BER performance at the degree of 8.93×10-3 with optical signal to noise ratio(OSNR)of24 d B,while the turbo coded system with transmission rate of 50 Gbit/s can achieve it within OSNR of 20 d B.

关键词： Bit error rate Decoding Error statistics Frequency division multiplexing Optical communication Optical signal processing Signal to noise ratio Turbo codes

来源：评论

学校读者我要写书评

暂无评论

Simultaneous measurement of refractive index, temperature and strain based on core diameter mismatch and polarization-maintaining FBG

引用

Optoelectronics Letters 2013年第3期9卷 238-240页

作者：童峥嵘王洁玉张卫华曹晔 Key Laboratory of Film Electronics and Communication Devices and Key Laboratory of Intelligent Computing and Novel Software Technology School of Computer and Communication Engineering Tianjin University of Technology

A kind of fiber-optic sensor for simultaneous measurement of refractive index of surrounding medium, temperature and strain is described. Based on core diameter mismatch, a multimode-single mode-multimode (MSM) structure is presented. It is demonstrated that the three parameters can be measured respectively by the interference of the core mode and cladding modes excited in the single mode fiber (SMF). Then combined with a polarization-maintaining fiber Bragg grating (PMFBG) which has different sensing properties from MSM structure, three parameters are measured simultaneously. The experimental results show that PMFBG is insensitive to the refractive index and the refractive index sensitivity of the MSM structure is 96.04 nm·RIU^(-1); the temperature sensitivities of the characteristic wavelength for MSM structure and the center wavelengths of fast and slow axes for PMFBG are 0.0911 nm °C^(-1), 0.00976 nm °C^(-1) and 0.0105 nm °C^(-1), respectively; the strain sensitivities of those are -0.013 nm με^(-1), 0.012 nm με^(-1) and 0.012 nm με^(-1), respectively.

关键词：温度敏感性应变灵敏度同时测量折射率不匹配光纤光栅直径 MSM结构

来源：评论

学校读者我要写书评

暂无评论

Highly birefringent photonic crystal fibers with flattened dispersion and low confinement loss

引用

Optoelectronics Letters 2013年第1期9卷 45-48页

作者：曹晔李荣敏童峥嵘 Key Laboratory of Film Electronics and Communication Devices Key Laboratory of Intelligent Computing and Novel Software Technology School of Computer and Communication Engineering Tianjin University of Technology

A highly birefringent index-guiding photonic crystal fiber (PCF) with flattened dispersion and low confinement loss is proposed by introducing two small air holes with the same diameter in the core area. The fundamental mode field, birefringence, confinement loss, effective mode area and dispersion characteristic of the fibers are studied by the full-vector finite element method (FEM). Simulation results show that a high birefringence with the order of 10 -3 and a low confinement loss of 0.001 dB/km are obtained at 1550 nm. Furthermore, flattened chromatic dispersion from 1450 nm to 1590 nm is obtained.

关键词：光子晶体光纤平坦色散高双折射损耗矢量有限元法气孔直径折射指数色散特性

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：