期刊：
Digital Signal Processing,2015年40(1):31-39 ISSN：1051-2004
通讯作者：
Ling, Bingo Wing-Kuen
作者机构：
[Ling, Bingo Wing-Kuen; Zhang, Xiao-Zhi] Guangdong Univ Technol, Fac Informat Engn, Guangzhou 510006, Guangdong, Peoples R China.;[Zhang, Xiao-Zhi] Univ South China, Engn Training Ctr, Fac Elect Engn, Hengyang 421001, Peoples R China.;[Subramaniam, Suba R.; Georgakis, Apostolos] Kings Coll London, Div Engn, Dept Elect Engn, London WC2R 2LS, England.
通讯机构：
[Ling, Bingo Wing-Kuen] G;Guangdong Univ Technol, Fac Informat Engn, Guangzhou 510006, Guangdong, Peoples R China.
关键词：
Rotated axis of time frequency plane;Fractional Fourier transform;Two sets of mask coefficients;Nonconvex global optimization;Modified filled function method
摘要：
The benefits of applying two mask operations in two different rotated axes of the time frequency (TF) plane are well known especially for signal restoration applications. Compared to just applying a single mask operation in a single rotated axis of the TF plane, it has been shown that applying two mask operations in two different rotated axes of the TF plane carefully can improve the restoration performances. However, there is no systematic approach for the globally optimal joint design of these two sets of mask coefficients in two different predefined rotated axes of the TF plane. In this paper, this optimal joint design problem is formulated as a nonconvex optimization problem. Then, a modified filled function method is employed for finding the globally optimal solution of the optimization problem. Computer numerical simulation results show that the obtained restoration system outperforms existing ones.
关键词：
Sensor scheduling;wireless sensor networks;multi-modal confident information coverage;set cover
摘要：
Network lifetime maximization with guaranteed coverage is an important issue in wireless sensor networks. Based on our recently proposed confident information coverage (CIC) model, this paper studies the multi-modal confident information coverage (M2CIC) problem. Assuming that each node is equipped with different types of sensors, the objective is to schedule the multi-modal sensors' activity, such that the confident information coverage for each sensing modality can be guaranteed while the network lifetime can be maximized. We model the M2CIC problem as a multi-modal set cover problem (M2SC) and prove its NP-completeness. For solving the M2SC problem, we design two energy-efficient heuristics including a centralized one and a distributed one. In the proposed algorithms, different modal sensors are organized into a family of set covers, each of which can provide confident information coverage for all the monitored physical phenomena. Simulation results show that both the proposed algorithms can efficiently prolong the network lifetime and outperform two classical peer algorithms in terms of the extended network lifetime.
作者机构：
[赵艳辉] School of Electrical Engineering, University of South China, Hengyang 421001, China;[刘才学; 踪训成] Nuclear Power Institute of China, Chengdu 610041, China;[黄顺] Department of Physics and Information Science, Hengyang Normal College, Hengyang 421008, China;[刘丽艳; 赵修良] School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
通讯机构：
School of Nuclear Science and Technology, University of South China, China
关键词：
中子注量率;放大甄别器;放大器增益;最小输入脉冲宽度;最大计数率
摘要：
为了测量反应堆内中子注量率分布，保证反应堆内活化55 M n-58 Ni合金探测片γ计数测量的可靠性，本文研制了中子注量率分布测量装置中9通道放大甄别器。多通道放大甄别器性能指标测试与应用测试结果表明：每个通道放大器增益1～21连续可调、甄别器阈值独立连续可调，具有最大计数率高、灵敏度高、稳定性好、系统抗串扰能力强等优点；放大器增益长期稳定性≤1％，甄别器最小输入脉冲宽度≥0.1μs ，甄别器最大计数率≤4×106 s-1，能用于实时长期稳定测量反应堆内中子注量率分布。
摘要：
We demonstrate an efficient scheme for controlling the tunneling ionization of a H2+ molecular ion. Our scheme is based on the idea that the tunneling ionization rate is highly dependent on the instantaneous magnitude of the electric field. By manipulating the relative phase of the synthesized 5-fs, 790–395-nm laser field, the fragments yielded by the tunneling ionization show a large asymmetry relative to the laser polarization. We find that the time-dependent ionization rate is sharply peaked near the antinodes of the synthesized field. Most importantly, the critical internuclear distances at which the tunneling ionization rate is enhanced depend on the field strength of the antinodes. It is well explained by tracing the laser-driven motion of the electron in the field-dressed double well potential.
期刊：
上海交通大学学报,2014年48:138-140 and 144 ISSN：1006-2467
通讯作者：
Ning, Zhi-Gang
作者机构：
[Cheng, Xiong; Ning, Zhi-Gang] College of Electrical Engineering, Nanhua University, Hengyang, Hunan, China;[Wang, Ren-Huang] Faculty of Automation, Guangdong University of Technology, Guangzhou, China
通讯机构：
College of Electrical Engineering, Nanhua University, Hengyang, Hunan, China
摘要：
Image fusion techniques aim at transferring useful information from the input source images to the fused image. The common assumption for most fusion approaches is that the useful information is defined by local features such as contrast, variance, and gradient. However, there is no consideration of global visual attention of the whole source images which indicates the "interesting" information of the source images. In this paper, we firstly review the patch-based image fusion methods which attract the attention and interest of many researchers. Then, a visual attention guided patch-based image fusion method is proposed. The visual attention maps of the source images are calculated from the sparse represent coefficients of the source images. Then, the sparse coefficients are fused with the guidance of visual attention maps in order to emphasize the global "interesting" objects in the source images. Finally, the fused image is reconstructed from the fused sparse coefficients. The new fusion strategy ensures that the objects being "interesting" for our visual system are preserved in the fused image. The proposed approach is tested on infrared and visual, medical, and multi-focus images. The results compared with those of traditional methods show obvious improvement in objective and subjective quality measurements. (C) 2014 Elsevier GmbH. All rights reserved.
期刊：
Lecture Notes in Electrical Engineering,2014年 237: 325-333 ISSN：1876-1100
通讯作者：
Zhao, Y.(gsxl666@163.com)
作者机构：
[Zhao, Yuhong] School of Electric Engineering, University of South China, Hunan, China;[Zhang, Yunhui] Eastern Boiler Control Company Limited, Shenzhen, China;[Hu, Heguo] Statistical Bureau of Hengyang City, Hunan, China
作者机构：
[王新林; 李月华; 唐一波; 朱卫华; 陈志勇] Department of Electrical Engineering, University of South China, Hengyang, China;[王新林; 陈冰] Department of Mechanical Engineering, University of South China, Hengyang, China
通讯机构：
Department of Electrical Engineering, University of South China, Hengyang, China
摘要：
Coverage is an important performance metric in sensor networks. The traditional disk coverage model uses a very simple geometric relation between a sensor and its surrounding space points to capture the sensor's sensing capability and quality, which are not enough for many practical applications. In this article, motivated from the application of precision agriculture, we propose a new confident information coverage model for field reconstruction, where the objective is to obtain reconstruction maps of some physical phenomena's attribute with a given reconstruction quality for the whole sensor field, including points been sampled and not sampled. The proposed model is downward compatible with the disk coverage model, while it can greatly reduce sensor density for area coverage. Simulation results show that for the same reconstruction quality, the required sensor density based on the proposed new model is much less than that based on the disk model in both the deterministic and random sensor deployment. In practice, the proposed model helps to determine the number of sensors to be deployed for a given farmland and their locations in the deterministic deployment. The proposed model can also help to guide network operations for energy efficient data collection with guaranteed reconstruction quality.
摘要：
3D finite-difference time-domain method (FDTD) is carried out to simulate femtosecond optical pulses incident on silver film perforated by subwavelength holes arrays. Both square arrays and hexagonal arrays of nanoholes in silver film are considered. It is found that optical transmittance of square arrays almost does not vary with the polarization direction of incident light, while optical transmittance of hexagonal arrays varies obviously, especially when the wavelength equals the periodicity of holes arrays. This will be important for applications of novel optical devices.
摘要：
A method for compensating nonlinear characteristic of thermocouple vacuum gauge is proposed. Least squares support vector machine (LS-SVM) is adopt as compensation model, of which parameters are optimized using particle swarm optimization (PSO) algorithm. Experimental results using data obtained on-site show that the proposed approach effectively compensates the nonlinearity characteristic, and the accuracy of this method is higher than those obtained by SVM model.
