Estimating a probability using finite memory

Let{X_{i}}_{i=1}^{infty}be a sequence of independent Bernoulli random variables with probabilitypthatX_{i} = 1and probabilityq=1-pthatX_{i} = 0for alli geq 1. Time-invariant finite-memory (i.e., finite-state) estimation procedures for the parameter p are considered which takeX_{1}, cdotsas an input sequence. In particular, an n-state deterministic estimation procedure is described which can estimate p with mean-square errorO(log n/n)and ann-state probabilistic estimation procedure which can estimatepwith mean-square errorO(1/n). It is proved that theO(1/n)bound is optimal to within a constant factor. In addition, it is shown that linear estimation procedures are just as powerful (up to the measure of mean-square error) as arbitrary estimation procedures. The proofs are based on an analog of the well-known matrix tree theorem that is called the Markov chain tree theorem.     

Logic operations in memory using a memristive Akers array

In-memory computation is one of the most promising features of memristive memory arrays. In this paper, we propose an array architecture that supports in-memory computation based on a logic array first proposed in 1972 by Sheldon Akers. The Akers logic array satisfies this objective since this array can realize any Boolean function, including bit sorting. We present a hardware version of a modified Akers logic array, where the values stored within the array serve as primary inputs. The proposed logic array uses memristors, which are nonvolatile memory devices with noteworthy properties. An Akers logic array with memristors combines memory and logic operations, where the same array stores data and performs computation. This combination opens opportunities for novel non-von Neumann computer architectures, while reducing power and enhancing memory bandwidth.     

Estimating 2-D DOA angles using nonlinear array configurations

This paper modifies the direction-of-arrival matrix (DOAM) method for detecting 2-D direction-of-arrival (DOA) angles of narrowband far-field source signals using nonlinear array configurations. The key modification to the DOAM method is the replacement of the 1-D data model with a 2-D data model. The modified DOA matrix (MDOAM) method requires less computation, detects more sources with the same number of sensors, and removes the constraint on the spacing between subarrays     

Phased array simulation using circular patch radiators

The circuit properties of a circular patch with center short-circuit pin is investigated in a rectangular grid array. It is found that feed probe direct radiation produces large variations in element-to-element coupling coefficients in theE-plane. For the investigated pairwise arrangement of feed probe positions the additional effect is unsymmetricE-plane coupling with respect to the direction toward the coupled element; this leads to unsymmetricE-plane scanning-induced impedance variation. The principal method of investigation is the small-array method using an8 times 8element array, but two waveguide simulators are used to check the results. It is concluded that the small array calculation provides reliable results for scanning angles greater than60degoff broadside. Active element match is observed to vary from -8.5 dB at broadside to about -20 dB on a60degscanning cone. Finally, a direct measurement of the dissipation losses of the patch radiator is presented using a waveguide simulator as a two-port network. At 5.5 GHz a - 0.3 dB dissipation loss is found.     

HgCdTe红外焦平面阵列像素内灵敏度函数仿真

对于<2的欠采样成像红外搜索和追踪系统,点目标能量集中在单像素内。由于焦平面阵列像素内灵敏度（IPS：Intra-Pixel Sensitivity）存在空间非均匀性,会降低目标的能量和质心测量精度。传统的光点扫描实验测试和数值仿真方法可有效表征和分析IPS,但系统和模型复杂度高、效率低,且实验测试无法分析IPS空间非均匀性与探测器参数的关系。针对上述问题,提出基于蒙特卡洛方法的HgCdTe红外焦平面阵列IPS仿真模型,分析了IPS空间非均匀性的影响因素。结果表明,减小像素中心距或增大吸收层厚度,IPS的空间非均匀性减小;随波长增大,IPS的空间非均匀性增大。该仿真和分析对高能量集中点目标测量精度的提升具有重要参考意义。     

Image processing on a memory array architecture

In this paper we examine the usefulness of a simple memory array architecture to several image processing tasks. This architecture, called theAccess Constrained Memory Array Architecture (ACMAA) has a linear array of processors which concurrently access distinct rows or columns of an array of memory modules. We have developed several parallel image processing algorithms for this architecture. All the algorithms presented in this paper achieve a linear speed-up over the corresponding fast sequential algorithms. This was made possible by exploiting the efficient local as well as global communication capabilities of the ACMAA.     

NUMERICAL SIMULATION OF ANNULAR PHASED ARRAY OF DIPOLE ANTENNAS USING THE FD-TD METHOD

The problem for calculating near fields of EM radiation systems by using the finitedifference time domain(FD-TD)method are discussed and the annular phased array of dipoleantennas has been simulated numerically by use of the FD-TD method.For a test run thenear field and current distribution of the single dipole antenna are calculated.The near fieldsof the annular phased array of dipole antennas in central region filled with deionized water arecomputed and the interaction of near fields with an anatomically-based inhomogeneous model ofhuman torso is considered as well.     

Design of a transmission gate based CMOL memory array

A design of a nanoelectronic memory array, compatible with both the molecular switch (nanodevice) electrical characteristics and CMOS 45 nm semiconductor technology node is presented. The proposed transmission gate based CMOL (hybrid CMOS/MOLecular) memory cell does not suffer from the operational difficulties faced by the conventional CMOL cell. The control circuitry with improved multiplexer designs is introduced, and it shows that the required voltage levels to program the nanodevices can be achieved. Moreover, the proposed memory cell has the same area as the existing CMOL inverter cell allowing easier implementation of both logic and memory circuits on the same chip.     

Phase change memory alloys: GST cell array characterization using picosecond ultrasonics

Phase change random access memory alloys (PRAM or PCM) are a class of non-volatile memory that is thought as viable alternatives to flash memory technology or to supplement other memory technologies depending on the end applications and its key performance requirements. Ge₂Sb₂Te₅ alloy (GST) is the most widely used chalcogenide material for PCM application, and has many unique properties, including strong temperature-dependent film properties, low thermal conductivity, and high electrical resistivity. Picosecond ultrasonics was used to make non-contact, non-destructive measurements of GST films on blanket wafers and directly on product wafers. On-product wafer measurements were made on various via array (0.5 μm and 1 μm between cell edges with CD size from 250 to 800 nm). Measurements have shown excellent correlation to cross-section SEM and were consistent with CMP polish times for both blanket and pattern wafer measurement. Excellent repeatability based on extensive measurements demonstrates the capability and reliability of picosecond ultrasonic technology. Picosecond ultrasonic measurements also provide rapid characterization across the whole wafer at production-worthy throughputs.     

基于Y形阵的空时二维波达方向估计

提出了一种适用于Y形阵的空时二维波达方向估计方法,在低信噪比下实现了无模糊的二维波达方向估计。该方法利用了Y形阵的特性,具有较好的稳定性和较小的估计方差。仿真结果证明了本方法的有效性。     

Estimating the number of errors in a system using a martingaleapproach

A new, efficient procedure estimates the number of errors in a system. A known number of seeded errors are inserted into a system. The failure intensities of the seeded and real errors are allowed to be different and time dependent. When an error is detected during the test, it is removed from the system. The testing process is observed for a fixed amount of time τ. Martingale theory is used to derive a class of estimators for the number of seeded errors in a continuous time setting. Some of the estimators and their associated standard deviations have explicit expressions. An optimal estimator among the class of estimators is obtained. A simulation study assesses the performance of the proposed estimators     

基于闪存阵列的缓存容量确定方法

针对低成本、小型化的数据记录系统的应用,提出了一种数据缓存技术解决方案。存储模块是由闪速存储器芯片（NAND Flash）组成的存储阵列,以FPGA为载体的SOPC系统作为存储模块的控制核心。分析存储系统的结构及控制平台的实现过程,并对系统工作原理及并行分路技术进行讨论。深入研究Flash阵列的存储过程,提出最小FIF...     

某型雷达对称振子阵列天线的设计与仿真

文中基于某型号雷达天线参数的设计指标,采用阵列天线的经典理论和泰勒综合法设计出符合要求的IX28阵列天线.并且还对阵列天线的阵元选择和设计,添加反射板和阵元间互耦等问题进行了研究.通过电磁场仿真软件HFSS进行了仿真试验,得出文中所设计的L波段对称振子阵列天线符合设计要求的结论.     

Two-dimensional computer simulation of the breakdown characteristics of a multi-element avalanche photodiode array

A two-dimensional computer simulation of the breakdown characteristics of a silicon multi-element avalanche photodiode array has been carried out. The effect of the interaction of the depletion layers of two adjacent avalanche photo diode (APD) elements on the breakdown voltage of the multi-element array has been modeled. The influence of the various physical parameters of the device on its breakdown voltage is investigated. Five different device structures are considered. Design guidelines for realizing true bulk breakdown in the device are presented. With the aid of these two-dimensional computer simulation results, the effect of scaling down the device dimensions, in an effort to increase the packing density of the device, on its breakdown voltage is also outlined.     

Design and simulation of a tactile display based on a CMUT array

In this article, we present the design of a tactile display based on a CMUT-phased array. The array implements a ‘pixel’ of the display and is used to focus airborne ultrasound energy on the skin surface. The pressure field, generated by the focused ultrasound waves, is used to excite the mechanoreceptors under the skin and transmit tactile information. The results of Finite Element Analysis (FEA) of the Capacitive Micromachined Ultrasonic Transducer (CMUT) and the CMUT-phased array for ultrasound emission are presented. The 3D models of the device and the array were developed using a commercial FEA package. Modelling and simulations were performed using the parameters from the POLYMUMPS surface micromachining technology from MEMSCAP. During the analysis of the phased array, several parameters were studied in order to determine their importance in the design of the tactile display. The output of the array is compared with the acoustic intensity thresholds in order to prove the feasibility of the design. Taking into account the density of the mechanoreceptors in the skin, we conclude that there should be at least one receptor under the excitation area formed on the skin.     

Nonrestoring binary division using a cellular array

An iterative array for nonrestoring division is described. It uses a logic cell which has been proposed for an array for binary square-root extraction. The array for binary division is fully iterative in terms of cell logic and in the interconnection pattern between the cells.     

Scalar quantisation using a fast systolic array

A systolic array capable of outperforming a table look-up quantiser is proposed. The design has high throughput, can perform uniform or non-uniform quantisation and is suitable for VLSI or field programmable gate array (FPGA) implementation. In the latter case, the array can be used dynamically to both reduce latency and switch between quantisers without the need to reset look-up tables     

Binary division using a data-dependent iterative array

An iterative array is proposed which can be used to carry out binary division based on the principle of successive subtraction. The function of each cell of the array is dependent on the result of subtraction in the array.     

多隧道结单电子动态存储器的Monte Carlo模拟

本文采用Monte Carlo方法模拟了多隧道结单电子动态存储器的存储特性，考察了隧道结的个数、隧道结电容、隧道结电阻、脉冲电压幅度等参数对存储器的存储时间和饱和充电电荷的影响，并与宏观RC电路进行了比较。     

Wideband array processing using a two-sided correlationtransformation

A new method for broadband array processing is proposed. The method is based on unitary transformation of the signal subspaces. We apply a two-sided transformation on the correlation matrices of the array. It is shown that the two-sided correlation transformation (TCT) has a smaller subspace fitting error than the coherent signal-subspace method (CSM). It is also shown that unlike CSM, the TCT algorithm can generate unbiased estimates of the directions-of-arrival, regardless of the bandwidth of the signals. The capability of the TCT and CSM methods for resolving two closely spaced sources is compared. The resolution threshold for the new technique is much smaller than that for CSM