Fast radix-2 division with quotient-digit prediction

An implementation of a radix-2 division unit is presented that uses prediction of the quotient digit. This prediction allows the concurrent computation of the quotient digit and the partial remainder. To achieve a simple quotient-digit selection, resulting in a step time roughly half of that of SRT division (without prediction), a simple estimate of the partial remainder is used, which requires that the divisor be scaled close to unity. This prescaling is simple to implement and increases the execution time by two cycles. We estimate a speed-up of 1.5 with respect to SRT division with redundant remainders.     

A radix-8 wafer scale FFT processor

Wafer Scale Integration promises radical improvements in the performance of digital signal processing systems. This paper describes the design of a radix-8 systolic (pipeline) fast Fourier transform processor for implementation with wafer scale integration. By the use of the radix-8 FFT butterfly wafer that is currently under development, continuous data rates of 160 MSPS are anticipated for FFTs of up to 4096 points with 16-bit fixed point data.     

Radix-2 SRT division algorithm with simple quotient digit selection

A new and fast algorithm for SRT division that combines a modified version of the Svoboda algorithm with the radix-2 signed-digit number system is presented. The quotient bit selection is a simple function of the two most significant digits of the current partial remainder, and the two operands are each prescaled by a single subtraction.<>     

An efficient method for L-filter design

For a given or estimated noise type, the determination of optimal L-filter coefficients is computationally intensive and extremely time consuming. Thus, even though the L-filters obtained are very successful in restoring signals corrupted by non-Gaussian noise, their on-line design in real-time applications is not practical. In this paper, a new methodology for the design of L-filters is presented in which the L-filter coefficients are obtained by approximating the covariance matrix of the ordered samples through the use of Taylor expansion. The paper also presents several examples that compare the proposed approach to the classical approach. The simulations show the value of the proposed approach.     

一种高效的自适应射线束追踪方法

提出了一种高效的射线追踪方法.该扩展传统射线追踪法的射线管成射线束.射线束可以根据求解空间自适应裁剪,解决了传统射线追踪法对空间的离散采样问题;摒弃了接收球技术,还解决了接收球技术带来的双计误差.该方法采用了基于Pluecker坐标系的射线束-三角形碰撞检测算法,使得提出的射线束追踪法具有很高的计算效率.该方法成功地应用于复杂场景下室内信道的预测,并与已公开发表的论文的测量值进行对比,一致性良好.     

An efficient method for plasma-charging damage measurement

The initial slope of the voltage versus time curve during constant current stressing of gate-oxide has been demonstrated, for the first time, as a good indicator for plasma-charging damage. This method of damage measurement measures the charge trapping rate of the gate-oxide directly while it is under a high-field stress. It combines the stressing and measuring steps in one rapid measurement. Using only capacitors as testing vehicle, this method does not require extensive processing. Using current stressing instead of CV measurement, this method greatly reduces the measurement time and the size requirement of the capacitor. The ability of this measurement method in bringing out the passivated defects after annealing is demonstrated. An example of using this method in detecting plasma-charging damage is included     

一种高效的基于矢量量化的彩色视频图像压缩编码方法

针对彩色视频图像提出了一种DCT域内基于矢量量化的高效编码方法。为去掉彩色图像各分量间的相关性,首先将图像由RGB空间转换到YUV空间,然后根据人类视觉特征（HVS）对色度信号U、V进行了亚采样和平均化处理;对亮度信号Y则进行分块DCT变换,并根据HVS特征对变化域内的块矢量进行自适应分类,然后根据矢量的类型分别构造码矢和进行全局码书设计。提出的全局码书设计方案可以根据帧间相关性及码字使用频率,对码书的内容自动进行更新和替换,以适应场景内容的变化。实验结果表明：在保证图像重建质量的前提下,本文提出的方法具有较高的压缩效率,比较适合于视频会议以及水下视频观测等应用场合。     

An efficient intra-mode decision method for HEVC

This paper proposes a new intra-mode decision method for HEVC. The proposed method makes use of the characteristics of some special modes that belong to both rough mode decision mode set and most probable mode set. It also improves the coding efficiency by adaptively applying different algorithms depending on the prediction unit size. Not only the luma components but also the chroma components are considered in this paper. In the intra-coding process for the chroma components, the proposed method changes the examination order and makes efficient use of the spatial correlation and coded block flag information. As a result, the proposed method shows significantly better performance compared to other intra-mode decision methods.     

一种高效的基于矢量量化的彩色视频图像压缩编码方法

针对彩色视频图像提出了一种DCT域内基于矢量量化的高效编码方法.为去掉彩色图像各分量间的相关性,首先将图像由RGB空间转换到YUV空间,然后根据人类视觉特征(HVS)对色度信号U、V进行了亚采样和平均化处理;对亮度信号Y则进行分块DCT变换,并根据HVS特征对变化域内的块矢量进行自适应分类,然后根据矢量的类型分别构造码矢和进行全局码书设计.提出的全局码书设计方案可以根据帧间相关性及码字使用频率,对码书的内容自动进行更新和替换,以适应场景内容的变化.实验结果表明:在保证图像重建质量的前提下,本文提出的方法具有较高的压缩效率,比较适合于视频会议以及水下视频观测等应用场合.     

产生安全椭圆曲线的一种有效方法

本文在寻找安全椭圆曲线的CM方法的基础上,实现了一种更具适用性的产生安全椭圆曲线的有效方法。通常,为了抵抗诸如MOV等算法可能的攻击,以域GF（q)上的椭圆曲线为基础的公钥密码系统,对该椭圆曲线必须要求满足以下条件：m阶曲线具有一个形式为2p 1的大素数因子,这是p是一个素数且q^2≠1modm。这个条件在不损害安全性的情况下对形式为2p 1的大素因子可以放宽到包括形式为2ip 1的素数（i是一个小整数）。因此,适用于公钥密码系统的安全椭圆曲线的数目显著增加。本文对这一方法进行了实现,它表明用该方法来产生适用于公钥密码系统的椭圆曲线比原来的方案快很多。     

Implementation of a low power 16-bit radix-4 pipelined SRT divider using a modified Split-Path Data Driven Dynamic Logic (SPDL) structure

In this paper a 16-bit radix-4 pipelined divider implemented in a modified version of SPD³L family structure (SPCD³L: Split-Path Clock-Data driven Dynamic Logic) is presented. Through the modification, the clock signal is also used to pre-charge some critical parts of the circuit. Performance of the circuit is evaluated at different simulation corners. The results show that, compared with Domino structure, the proposed circuit has lower power consumption and higher speed. Latency of the divider is equal to 10 half clock cycles. The design is simulated using HSPICE in a 1.8-V TSMC_180 nm CMOS process.     

An efficient BIST method for distributed small buffers

In this work, we propose a new built-in self-testing (BIST) method that is able to concurrently test a set of spatially distributed embedded-memory modules with different sizes. Using the concept of redundant read-write operations, we develop a new march method, called RSMarch, to efficiently test each memory module. The new method has the advantages of low hardware overhead, short test time, and high-fault coverage. The total test time is dominated by large-size modules. To further reduce the test time, we also propose a split-mode test method to virtually partition each large memory array into smaller modules, which can be tested simultaneously.     

An efficient method for evaluating network-reliability withvariable link-capacities

An efficient method is proposed to evaluate the network reliability with variable link capacities when the simple paths of the network are known. Most of the evaluation techniques proposed in the literature so far are based on enumerating the k-composite paths, each of which is a union of k simple paths. Although some of those methods lead to correct results, the redundancy is still quite large and may occur repeatedly each time the higher order composite paths are generated. This paper proposes a new method based on the concepts of additivity and eligibility properties defined in the text. The authors identify a composite path as a subnetwork which in general contains more simple paths than those involved in composition, and add only a minimal set of links at each step which gives maximal increase on the maximum capacity flow of the subnetwork. Thereby, they reduce the possible occurrence of redundancy significantly. The number of composite paths considered for the capacity computation is also greatly reduced. Furthermore, it is not necessary to keep the information on how many and which simple paths have been used in each composite path. Some numerical examples illustrate the efficiency of the method     

An efficient DOA estimation method in multipath environment

An efficient direction of arrival (DOA) estimation method is proposed with uniform linear array (ULA) in multipath environment. By applying a transformation, we can convert a constructed complex matrix to a real one, and then utilize the real matrix combined with our proposed criterion to estimate the DOAs of uncorrelated signals. Afterwards, the contributions of uncorrelated signals are eliminated, and then several new matrices without the information of uncorrelated signals are constructed to resolve the remaining coherent signals. The proposed estimation method overcomes the shortcomings of the existing methods and has satisfactory performance. Simulation results confirm the theoretical analysis and show the effectiveness of the proposed method.     

一种有效的邻近效应修正方法

本文介绍了在电子束光刻中修正邻近效应的一种有效的剂量补偿方法。在其它曝光参数一定的条件下（包括加速电压,抗蚀剂厚度,曝光步长大小及衬底材料等）图形尺寸由剂量大小决定。本方法基于两种合理的假设来确定补偿剂量因子。一是假设在特定实验范围内,剂量的大小和圆直径的关系可以看作是线性的。二是假设补偿剂量因子仅受最近邻图形的影响。四层六角光子晶体作为本实验方法的测试图形。比较没有修正的结构,修正后的结构中孔大小的一致性得到了显著的提高     

An efficient PML implementation for the ADI-FDTD method

A novel implementation of the perfectly matched layer (PML) absorber for the alternating-direction implicit finite-difference time-domain method is proposed and implemented. It is shown that, compared to the traditional PML implementation, the performance of the proposed PML is more efficient for large Courant numbers.     

An efficient method for dynamic magnetic resonance imaging

Many magnetic resonance imaging applications require the acquisition of a time series of images. In conventional Fourier transform based imaging methods, each of these images is acquired independently so that the temporal resolution possible is limited by the number of spatial encodings (or data points in the Fourier space) collected, or one has to sacrifice spatial resolution for temporal resolution. Here, a generalized series based imaging technique is proposed to address this problem. This technique makes use of the fact that, in most time-sequential imaging problems, the high-resolution image morphology does not change from one image to another, and it improves imaging efficiency (and temporal resolution) over the conventional Fourier imaging methods by eliminating the repeated encodings of this stationary information. Additional advantages of the proposed imaging technique include a reduced number of radio frequency (RF) pulses for data collection, and thus lower RF power deposition. This method should prove useful for a variety of dynamic imaging applications, including dynamic studies of contrast agents and functional brain imaging.     

An efficient motion-resistant method for wearable pulse oximeter

Reduction of motion artifact and power saving are crucial in designing a wearable pulse oximeter for long-term telemedicine application. In this paper, a novel algorithm, minimum correlation discrete saturation transform (MCDST) has been developed for the estimation of arterial oxygen saturation (SaO2), based on an optical model derived from photon diffusion analysis. The simulation shows that the new algorithm MCDST is more robust under low SNRs than the clinically verified motion-resistant algorithm discrete saturation transform (DST). Further, the experiment with different severity of motions demonstrates that MCDST has a slightly better performance than DST algorithm. Moreover, MCDST is more computationally efficient than DST because the former uses linear algebra instead of the time-consuming adaptive filter used by latter, which indicates that MCDST can reduce the required power consumption and circuit complexity of the implementation. This is vital for wearable devices, where the physical size and long battery life are crucial.     

Efficient implementation of 3X for radix-8 encoding

Several commercial processors have selected the radix-8 multiplier architecture to increase their speed, thereby reducing the number of partial products. Radix-8 encoding reduces the digit number length in a signed digit representation. Its performance bottleneck is the generation of the term 3X, also referred to as hard multiple. This term is usually computed by an adding and shifting operation, 3X=2X+X, in a high-speed adder. In a 2X+X addition, close full adders share the same input signal. This property permits simplified algebraic expressions associated to a 3X operation other than in a conventional addition. This paper shows that the 3X operation can be expressed in terms of two signals, H_i and K_i, functionally equivalent to two carries. H_i and K_i are computed in parallel using architectures which lead to an area- and speed-efficient implementation. For the purposes of comparison, implementation based on standard cells of conventional adders has been compared with the proposed circuits based on these H_i and K_i signals. As a result, the delay of the proposed serial scheme is reduced by roughly 67% without additional cost in area, the delay and area of the carry look-ahead scheme is reduced by 20% and 17%, and that of the parallel prefix scheme is reduced by 26% and 46%, respectively.