一种10 bit 1 MS/s SAR ADC的设计实现

基于0.13μm CMOS工艺,设计了一种采样率达到1 MS/s的10位逐次逼近模数转换器,其中逐次逼近数字控制逻辑采用全定制的方法,减小了数字单元的面积和功耗;比较器中的预放大器分别采用了二极管连接和开关管复位的方式将各级运放的输出短接,加快比较速度,最后一级锁存器采用改进的两级动态锁存器,进一步提升比较速度的同时降低了失调误差。实验结果表明,1.2 V电源电压下,所设计的ADC采样率达到1 MS/s,输入信号频率为12.5 kHz时,测得的输出信号信噪比为54.47 dB,SFDR为45.18 dB。     

A simple and efficient watermark technique based on JPEG2000 Codec

In this paper we propose an effective watermark scheme for embedding and extracting based on the JPEG2000 Codec process. Our embedding algorithm applies the torus automorphisms (TA) technique to break up and scramble a watermark. The scrambled watermark was embedded into the quantized bitstreams of JPEG2000 before the entropy coding stage. Distortion reduction (DR) was applied to the compressed image to lessen image degradation caused by the embedding process. Our watermark scheme is simple and easy to implement. Furthermore, it is robust to attacks like blurring, edge enhancement, and other image processing manipulations.Corespondence to: J. Chen (P.O. Box 63-146, Taichung, Taiwan 406, R.O.C.)     

A highly efficient reconfigurable rotation unit based on an inverse butterfly network

We propose a reconfigurable control-bit generation algorithm for rotation and sub-word rotation operations. The algorithm uses a self-routing characteristic to configure an inverse butterfly network. In addition to being highly parallelized and inexpensive, the algorithm integrates the rotation-shift, bi-directional rotation-shift, and sub-word rotation-shift operations. To our best knowledge, this is the first scheme to accommodate a variety of rotation operations into the same architecture. We have developed the highly efficient reconfigurable rotation unit (HERRU) and synthesized it into the Semiconductor Manufacturing International Corporation (SMIC)’s 65-nm process. The results show that the overall efficiency (relative area×relative latency) of our HERRU is higher by at least 23% than that of other designs with similar functions. When executing the bi-directional rotation operations alone, HERRU occupies a significantly smaller area with a lower latency than previously proposed designs.     

基于去调频技术的斜视聚束SAR成像方法

针对具有方位谱混叠现象的斜视聚束式合成孔径雷达(SAR)成像问题,本文研究了一种基于去调频技术的成像方法.文中首先分析了斜视聚束SAR中的方位谱混叠现象,从理论上找出了斜视角影响方位粗聚焦的根本原因.基于分析结果,引入了回波信号非线性相位校正预处理法,彻底消除了斜视角的影响,从而得到正确的粗聚焦结果.然后基于斜视成像模型,推导了预处理回波信号的方位粗聚焦和精聚焦处理过程.在精聚焦的方位滤波处理中,针对非线性相位校正预处理导致的场景聚焦深度限制问题,提出了一种改进的非线性调频变标(NLCS)算法,实现了回波信号的高精度方位压缩.仿真实验结果证明了文中理论分析的正确性和所提方法的有效性.     

A fast and efficient image registration algorithm using outlier rejection technique based on subimage

Image registration is a process of overlaying two or more images of the same scene taken at different times, from different viewpoints, and by different sensors. It geometrically aligns two images, the reference and sensed image. In this paper, a fast and efficient image registration algorithm is proposed for IDS (Intruder Detection System). To reduce a calculation time, outlier rejection method based on uniformity, entropy and subimage is used. An edge tapering method is applied to alleviate a boundary effect of a subimage. And it is shown that the proposed algorithm improves the accuracy and calculation time effectively.     

一种基于DWT和位平面的数字水印算法

为了更好的保护数字图像的版权,本文提出一种基于小波变换嵌入水印到图像位平面的算法,主要通过一种改进的方法来修改灰度图像的位平面小波变换系数嵌入水印。实验表明,该算法提高了水印的相似度,保证了图像的质量有较好的鲁棒性和不可见性。     

The internet of everything based on energy efficient P2P transmission technology with Bluetooth low energy

This paper introduces a fundamental energy efficient hybrid P2P transmission technology for P2P networking environment as well as Internet of Everything (IoE) infrastructure. Based on the transmission characteristics of wireless communication technologies of Bluetooth and Wi-Fi, the proposed P2P transmission technique integrates them into an energy efficient hybrid transmission technology and provides the IPification for specific group, society, and the entire world. We have shown that the proposed hybrid transmission technology outperforms the existing transmission technologies in the aspects of initial connection establishment time and overall data transmission capability.     

A sliding window technique for efficient license plate localization based on discrete wavelet transform

Real-time license plate recognition (LPR) is an interesting but complicated research topic. Some previous works use discrete wavelet transform (DWT) to extract license plate (LP), however, most of them are not capable of dealing with complex environments such as the low-contrast source images and the dynamic-range problems. In this paper, we propose an algorithm for license plate localization (LPL) based on DWT. The LP can be extracted from different quality of source images under complex environments by using two frequency subbands. We first use the HL subband to search the features of LP and then verify the features by checking whether in the LH subband there exists a horizontal line around the feature or not. The proposed method can extract both front and back LPs of various vehicles. The experimental results show that the proposed method can achieve good LPL results with both short run-time and high accurate detection rate.     

Optimized area efficient quantum dot cellular automata based reversible code converter circuits: design and energy performance estimation

The Journal of Supercomputing - Quantum-dot cellular automata (QCA) based circuit designs are creating a surge in transistorless computational technologies. Due to its quasi-adiabatic switching...     

A multilevel color image segmentation technique based on cuckoo search algorithm and energy curve

Amongst all the multilevel thresholding techniques, standard histogram based thresholding approaches are very impressive for bi-level thresholding. But, it is not effective to select spatial contextual information of the image for choosing optimal thresholds. In this paper, a new color image thresholding technique is presented by using an energy function to generate the energy curve of an image by considering spatial contextual information of the image. The property of this energy curve is very much similar to histogram of the image. To estimate the spatial contextual information for thresholding practice, in place of histogram, the energy curve function is used as an input. A new energy curve based color image segmentation approach using three well known objective functions named Kapur’s entropy, between-class-variance, and Tsalli’s entropy is proposed. In this paper, cuckoo search (CS) and egg lying radius-cuckoo search (ELR-CS) optimization algorithms with different parameter analysis have been used for solving the color image multilevel thresholding problem. The experimental results demonstrate that the proposed CS-Kapur’s energy curve based segmentation can powerfully and accurately search the multilevel thresholds.     

Repetitive node categorization technique based reliable clustering and energy efficient communication in P2P wireless sensor network

Peer-to-Peer Networking and Applications - Peer to Peer (P2P) Wireless Sensor Networks (WSNs) acts as a critical purpose in today’s real-world applications. It contains spatially disseminated...     

基于重置算法的感应电机转速自适应观测器

常规并联双模型转速自适应观测器在电机启动、加速或突加负载时存在观测转速滞后性大、精度低的问题, 使得感应电机无速度传感器控制系统的调速性能变差. 针对上述问题, 提出一种重置自适应转速观测器对转子磁链进行观测, 同时通过自适应机构得到电机转速, 并利用Lyapunov 稳定性定理证明了系统的稳定性. 仿真和实验结果表明, 所提出的重置自适应观测器的观测误差小、稳定性好, 改善了在电机启动、加速或突加负载时的转速观测性能.

     

基于非下采样Contourlet变换的方向Teager能量的极化SAR图像融合*

提出一种基于非下采样Contourlet变换和方向Teager能量的极化SAR图像融合算法。采用具有多尺度、多方向和平移不变性特点的非下采样Contourlet变换对多个单极化强度图像进行分解,然后高频子带图像分别按行和列进行Teager能量计算,选取Teager能量作为度量来提取区域边缘与纹理信息。对于低频系数采用平均融合算法,根据高频子图Teager能量分布差异,对于方向高频系数采用不同最优加权算法实现极化图像的融合处理。实验结果表明,提出的算法与PWF算法相比在保留原始图像边缘和纹理信息的同时,可以有效地抑制相干斑噪声的影响,取得较好的融合视觉效果。     

A multi-level optimization technique based on fuel consumption and energy index in early-stage ship design

Reducing lifetime fuel consumption (LFC) and energy efficiency design index (EEDI) are two of the main concerns of shipping industry in recent years. This paper presents a multi-disciplinary and multi-level optimization scheme-based software (HPS-MOP2) to design a hull–propeller system simultaneously from the LFC and EEDI point of view in early-stage ship design. Calculations of the ship resistance and propeller performance are essential to optimize the ship hull–propeller system. Two numerical methods with variable fidelity, non-uniform rational basis spline (NURBS) geometry modelling technique and new version of multi-objective evolutionary algorithm based on decomposition (MOEA/D) are three main parts of the proposed methodology. A bulk carrier propelled by a well-known propeller is used as a base model in three different study cases based on specific fuel oil consumption (SFOC) curves provided by the engine manufacturers Wartsila, MAN and Caterpillar. The presented results illustrate that the employed approach may achieve cost- and energy-efficient designs.

     

An efficient shape optimization technique of a two-dimensional body based on the boundary element method

An efficient approximation method to determine the optimum shape of the minimum weight of a body subjected to stress and displacement constraints is suggested by using the boundary element method. The objective function of weight is approximated to an expansion of a second-order Taylor series and the stress and displacement constraints to expansions of a first-order Taylor series, based on the boundary element sensitivity analysis at the current design point. The approximated subproblem is then solved by a linear complementary pivot method. Design variable reduction techniques of isoparametric interpolation and trigonometric series interpolation for the design boundary shape are also adopted for reducing the degrees of freedom of the design problems.     

Rapid and efficient image restoration technique based on new adaptive anisotropic diffusion function

The anisotropic diffusion is an efficient smoothing process. It is widely used in noise removing and edges preserving via different schemes. In this paper based on a mathematical background and the existing efficient anisotropic function in the literature we developed a new mathematical anisotropic diffusion function which is able to overcome the drawbacks of the traditional process such as the details loss and the image blur. The simulations results and the comparative study with other recent techniques are conducted and showed that the proposed schema generates a wide improvement in the quality of the restored images. This improvement has been shown subjectively in terms of visual quality, and objectively with reference to the computation of some criteria. The simulated images are well de-noised but the most important is that details and structural information are kept intact. In addition to that, the proposed new function was found very interesting and presents numerous advantages like its similarity to the conventional model and the importance of the speed hence it converges faster which allows an opportunity to be well implemented in our de-noising process.     

基于节点能量和网络稳定性的节能路由协议

在Ad hoc网络中,AODV等路由协议在选择路由路径时没有考虑节点的能量,可能造成部分节点的能量过度使用从而导致网络分割等问题。以AODV为基础,提出了一种基于节点剩余能量和网络稳定性的路由算法ECAODV。该算法在路由发现过程中,不仅要综合考虑路径上的节点的剩余能量和路由跳数,而且考虑路径中间节点对网络稳定性的影响。通过仿真验证该算法有较好的性能。     

Designing a pseudorandom bit generator based on LFSRs and a discrete chaotic map

A new method for the generation of pseudorandom numbers, based on two linear feedback shift registers (LFSRs) and a discrete-space chaotic map is presented. The proposed method consists of multiple stages; in stage one a pseudorandom sequence is generated. In stage two a selection of output bits is conducted in order to produce sequences with high randomness. Because many previous methods based on LFSRs and XOR operations are not able to resist chosen and known plaintext attack, stage one of the proposed method is designed to be resistant to this problem. Relations between two LFSRs and the parameters of the chaotic map are established in such a way that based on known output bits of a proposed generator it is impossible to obtain any part of the secret key without guessing the whole secret key. The randomness of generated sequences is confirmed using NIST, TestU01, and the DIEHARD test. The advantages of the proposed method are virtually unlimited key space and resistance to digital degradation.     

基于MPEG4高效视频DCT编码器的实现

提出并实现了一个基于MPEG4的快速高效存储的DCT视频编码器,用它把H.261视频数据流转换为低比特率、低空间分辨率的MPEG4流,并进行无线视频处理。和现有编码器相比,它不仅能够大大地节省存储空间,计算复杂度也降低了许多,实验结果表明用该编码器得到的视频质量与用象素领域方法得到的视频质量相当。     

基于IWT和最低有效位替换的视频隐写算法

为了更好地增强加密通信的安全性和鲁棒性,提出一种基于整数小波变换(IWT)和最低有效位(LSB)替换的视频隐写算法,该算法可以对红绿蓝(RGB)三色构成的视频文件进行数据隐藏和提取。隐写过程首先将覆盖视频划分为8×8的RGB图像块,加密数据转化为二进制形式的文本;然后在覆盖视频上执行Haar IWT以获取IWT系数;最后,将二进制文本嵌入到IWT系数的LSBs中。其中数据隐藏的反向过程用于提取隐写视频中的嵌入文本。采用音频视频交错(AVI)文件执行本文算法,实验结果表明,本算法的失真最低。