Generation of quadratic potential force fields from flow fields for distributed manipulation

Distributed manipulation systems induce motions on objects through the application of many external forces. Many of these systems are abstracted as planar programmable force fields. Quadratic potential fields form a class of such fields that lend themselves to analytical study and exhibit useful stability properties. This paper introduces a new methodology to build quadratic potential fields with simple devices using the naturally existing phenomena of airflow, which is an improvement to the traditional use of the complicated programmable actuator arrays. It also provides a basis for the exploitation, in distributed manipulation, of natural phenomena like airflow, which require rigorous analysis and display stability difficulties. A demonstration and verification of the theoretical results for the special case of the elliptic field with airflows is also presented.     

相变存储器离散地址数据写入读出控制系统设计

采用传统系统受到干扰信号影响,控制能力变差,提出设计一种基于可编程逻辑阵列方式的相变存储器离散地址数据写入读出系统,可改善控制能力。选用Xilinx公司的Spartan-6芯片作为配置基础,设计抗干扰可编程逻辑阵列主—被动配置方案,促使硬件具有抵抗信号干扰的能力,以该方案对电路进行连接;将硬件主—被动配置软件功能进行设计,以时序图来展示控制结果,可抵抗外界信号造成的干扰。通过实验结果得出,该系统最低控制能力也可达到80%,即使在强信号干扰下,也能对离散地址数据写入与读出进行有效控制。     

DDS芯片AD9854在脉搏波阻抗谱测量中的应用

采用脉搏波阻抗谱法能够有效地减小个体差异和测量条件对阻抗测量的影响,是一种很有前景的血液成分无创检测方法.波阻抗谱测量系统需要两路同频严格正交信号源,且信号频率在要求范围内程控可调.采用直接数字脉搏合成技术,以DDS芯片AD9854为核心设计了用于脉搏波阻抗谱测量系统的恒流驱动信号源.实验结果表明:采用AD9854,电路设计简单,工作可靠,容易实现频率调整,频谱稳定度和精确度以及相位误差满足测量系统要求.     

用8255实现PC机与智能接口卡间并行通信

智能接口卡与其所在主机间实现并行通信的方法有多种,例如可使用锁存器和缓冲器等简单并行接口实现,也可使用双端口存储器、FIFO存储器等方法实现,但这些方法都需考虑隔离问题,硬件电路较复杂.在详细分析8255可编程并行接口芯片工作方式2原理的基础上,以采用8031CPU构成PC机智能接口卡为例,论述了采用两片8255实现PC机与智能接口卡间并行通信的方法,给出了具体接口电路,并详细分析了该接口电路的工作原理及特点.     

Montgomery exponent architecture based on programmable cellular automata

This study presents an efficient exponent architecture for public-key cryptosystems using Montgomery multiplication based on programmable cellular automata (PCA). Multiplication is the key operation in implementing circuits for cryptosystem, as the process of encrypting and decrypting a message requires modular exponentiation which can be decomposed into multiplications. Efficient multiplication algorithm and simple architecture are the key for implementing exponentiation. Thus we employ Montgomery multiplication algorithm and construct simple architecture based on irreducible all one polynomial (AOP) in GF(2^m). The proposed architecture has the advantage of high regularity and a reduced hardware complexity based on combining the characteristics of the irreducible AOP and PCA. The proposed architecture can be efficiently used for public-key cryptosystem.     

Shrink-induced single-cell plastic microwell array

The ability to interrogate and track single cells over time in a high-throughput format would provide critical information for fundamental biological understanding of processes and for various applications, including drug screening and toxicology. We have developed an ultrarapid and simple method to create single-cell wells of controllable diameter and depth with commodity shrink-wrap film and tape. Using a programmable CO(2) laser, we cut hole arrays into the tape. The tape then serves as a shadow mask to selectively etch wells into commodity shrink-wrap film by O(2) plasma. When the shrink-wrap film retracts upon briefly heating, high-aspect plastic microwell arrays with diameters down to 20 μm are readily achieved. We calibrated the loading procedure with fluorescent microbeads. Finally, we demonstrate the utility of the wells by loading fluorescently labeled single human embryonic stem cells into the wells.     

MEMS可编程光栅动态驱动电路的研制

MEMS可编程光栅的工作性能很大程度依赖于驱动电路的性能。本文根据MEMS可编程光栅的工作特点及结构参数,提取出光栅的等效电容值,并采用集成高压运放研制出一种新型的MEMS可编程光栅的动态驱动电路。为了避免自激振荡的发生,电路中采用了频率补偿和并联反馈电容的方法,有效提高了电路的稳定性。实际电路经过测试,其动态性能与PSPICE10仿真的结果非常吻合。该动态驱动电路具有高的电压输出范围(0~180V),较高的频率响应(10kHz),大范围容性负载能力(1~1000pF),完全能够满足MEMS可编程光栅动态复杂控制的需要。     

Modeling planar slider-crank mechanisms with clearance joints in RecurDyn

Revolute joints in applications always show clearance between pin and bushing due to manufacturing tolerances, the need of relative motion or progressing wear. Many researchers developed and investigated methodologies to calculate the dynamic behavior of mechanisms with such imperfect joints. Very often they use a simple slider-crank mechanism to test or demonstrate the capability of their approaches. In this paper, a methodology for simulating a slider-crank mechanism with an imperfect revolute joint in RecurDyn, a commercial multibody simulation tool, is presented. Therefore, a thorough investigation of existing contact, damping and friction force models as well as different ways of modeling revolute joints in RecurDyn was conducted. For the investigation of the damping models, a special program for calculating the model parameters for a given coefficient of restitution was developed. Only one damping model was capable of reproducing the experimental results, which were found in literature. Some characteristic results of the slider-crank mechanism are presented in a way that they can be compared to results in other papers. Thereby. a good correlation was achieved, demonstrating the capabilities of the methodology.     

一种简易温度测量装置的设计

本文介绍了一种简易温度测量装置的硬件与软件设计。该装置以DS18820为温度传感器，温度显示采用虚拟I^2 C总线方式。文中给出了温度传感器、温度显示与P89C51RD2电片机的接口技术及实例。这种温度测量装置结构简单，使用方便、可靠。     

An object-oriented cooperative distributed problem solving shell with groupware management ability

In this paper, an Object-Oriented Cooperative Distributed Problem Solving Shell (OOCDPSS) with groupware management ability is designed. The groupware management facilities, which satisfy the needs of development and execution of the cooperative distributed problem solving activities, can reinforce concurrency and parallelism, accommodation and integration of heterogeneous, uncoordinated problem solvers cooperating on one common goal. This OOCDPSS system constructs the non-embedded groupware architecture by a hierarchy of leader agents. The leader agent that adopts a distributed blackboard control mechanism can assist the cooperating problem solvers with all the cooperative and coordinative activities at run time through a democratic, contract-net protocol. In this blackboard control mechanism, the system control unit and domain control unit are explicitly separated and put side-by-side in a simple control loop to simplify the control mechanism design. The event messages drive the above control units with the programmable heuristic knowledge, including the static knowledge, procedural knowledge, and strategic, situation-action behavior knowledge. In this OOCDPSS, a completely transparent environment and a programmable distributed blackboard control mechanism are provided. This environment automatically assists and supervises the progress of cooperative problem solving activities at run time, thereby raising the effective level of use among the preexisting problem solvers. In addition, by using the programmable heuristic knowledge, our approach can be efficiently implemented on the cooperative problem solving plans with a range of configurations. ©1997 John Wiley & Sons, Ltd.     

A simple method for predicting the secondary structure of globular proteins: implications and accuracy

A method is presented for predicting the secondary structure of globular proteins from their amino acid sequence. It is based on a rigorous statistical exploitation of the well-known biological fact that the amino acid compositions of each secondary structure are different. We also propose an evaluation process that allows us to estimate the capacity of a method to predict the secondary structure of a new protein which does not have any homologous proteins whose structure is already known. This evaluation process shows that our method has a prediction accuracy of 58.7% over three states for the 62 proteins of the Kabsch and Sander (1983a) data bank. This result is better than that obtained by the most widely used methods--Lim (1974), Chou and Fasman (1978) and Garnier et al. (1978)--and also than that obtained by a recent method based on local homologies (Levin et al., 1986). Our prediction method is very simple and may be implemented on any microcomputer and even on programmable pocket calculators. A simple Pascal implementation of the method prediction algorithm is given. The interpretation of our results in terms of protein folding and directions for further work are discussed.     

一种基于DSP的短波MODEM硬件设计

模拟接口芯片(AIC)具有高度可编程性、与DSP接口简单、高性能低功耗等特点.本文介绍了一种基于TLV320AIC10和TMS320C54x的短波MODEM的硬件设计方案,并给出TLV320AIC10的初始化代码.     

Design and Implementation of Discrete Event Control Systems: A Petri Net Based Hardware Approach

This paper presents a methodology for modeling and hardware implementation of discrete event control systems based on the formalism of Petri nets (PN). The control algorithm is initially specified as an executable PN specification which is subsequently compiled directly into a compact machine code and stored in commercially available programmable read only memory (PROM). As an implementation platform, a programmable Petri net based dedicated discrete event controller is proposed. The scalable architecture of the controller is optimized to process PN constructs of all possible classes. A remarkable feature of the proposed architecture is its ability to handle explicit concurrency. The controller exploits hardware-level parallelism to track multiple tokens (control threads) through the net. The performance of the architecture has been verified and benchmarked on the fabricated integrated circuit (IC) prototype of the controller.     

一种工作频率可调的锁定放大电路在液体微弱电导测量中的应用

提出了一种基于直接数字合成(DDS)技术的锁定放大电路设计.该电路工作频率可在0～1.25 MHz范围内调整,并具有自动相位跟踪的特点.该电路成功应用于液体微弱电导的高分辨率测量.实验结果表明,在1～50μS的测量范围内,电路的分辨率高于0.01μS.此电路作为一种通用锁定放大电路也适用其它类似的微弱信号检测应用.     

DOP—a simple processor for custom computing machines

A general-purpose processor cell, called DOP, is presented. The DOP architecture is designed to support efficiently high-level programming languages (HLLs) such as C or Pascal, but still be simple enough to be implemented on one field programmable gate array (FPGA). Special attention is paid to the analysis of HLL requirements on processors. The DOP is designed to be used as a building block (cell) in a FPGA library. Its simplicity allows other microcomputer functional units to be implemented on the same FPGA. The DOP serves as a core for simple solutions using currently available technology.     

一种可重配置的存储器测试控制器设计

存储器在SOC中所占的电路面积越来越大,因此存储器的正确与否影响着SOC芯片的成品率。存储器中的故障种类繁多,单一的测试方法不能保证所有故障的100%覆盖率。本文通过对广泛应用的March算法进行了分析,提出了一种可重配置的存储器测试方法。在该方法中通过设置一组控制寄存器就可以灵活的实现各种March算法。另外,采用资源复用的方法,在嵌入式微处理器核中增加了一个有限状态机,几个控制寄存器和几条专门用于存储器测试的指令,可以方便的实现各种March算法,并且硬件开销非常小。     

Dynamic hardware plugins: exploiting reconfigurable hardware for high-performance programmable routers

This paper presents the dynamic hardware plugins (DHP) architecture for implementing multiple networking applications in hardware at programmable routers. By enabling multiple applications to be dynamically loaded into a single hardware device, the DHP architecture provides a scalable mechanism for implementing high-performance programmable routers. The DHP architecture is presented within the context of a programmable router architecture which processes flows in both software and hardware. Implementation options are described as well as the prototype testbed at Washington University in Saint Louis which utilizes the partial reconfiguration capability of modern field programmable gate arrays.     

差压式涡街质量流量计信号处理系统的研制

差压式涡街质量流量计是一种新型的质量流量测量装置,通过测量旋涡发生体上下游管壁处的差压,同时获取涡街频率信号和压力损失信号.为了将差压中这两路信号分离并准确测量其值,研制了采用程控放大、自适应滤波技术及FFT算法的信号处理系统.实验结果表明,该信号处理系统能够准确地从差压式涡街质量流量计输出信号中测得管内流体的质量流量值,同时改善了装置的抗干扰能力和通用性,提高了涡街频率测量的准确度,并且具有结构简单、成本低、适用性广等优点.     

A stochastic approach to shortcut bridging in programmable matter

In a self-organizing particle system, an abstraction of programmable matter, simple computational elements called particles with limited memory and communication self-organize to solve system-wide problems of movement, coordination, and configuration. In this paper, we consider a stochastic, distributed, local, asynchronous algorithm for “shortcut bridging”, in which particles self-assemble bridges over gaps that simultaneously balance minimizing the length and cost of the bridge. Army ants of the genus Eciton have been observed exhibiting a similar behavior in their foraging trails, dynamically adjusting their bridges to satisfy an efficiency trade-off using local interactions. Using techniques from Markov chain analysis, we rigorously analyze our algorithm, show it achieves a near-optimal balance between the competing factors of path length and bridge cost, and prove that it exhibits a dependence on the angle of the gap being “shortcut” similar to that of the ant bridges. We also present simulation results that qualitatively compare our algorithm with the army ant bridging behavior. Our work gives a plausible explanation of how convergence to globally optimal configurations can be achieved via local interactions by simple organisms (e.g., ants) with some limited computational power and access to random bits. The proposed algorithm also demonstrates the robustness of the stochastic approach to algorithms for programmable matter, as it is a surprisingly simple extension of our previous stochastic algorithm for compression.     

新型矿用便携式静态电阻应变仪的研制

为了解决目前开采速度较快或分叉巷道多的矿井使用固定应变仪安装复杂、维护困难、成本较高等突出问题,提出了一种新型矿用便携式静态电阻应变仪。该应变仪以ATmega16L单片机为主控芯片,硬件上采用电子程控开关切换、精密仪表放大器和先进低频滤波等对信号采集调理,LCD显示检测结果,利用专用时钟芯片记录巷道顶板压力检测时间,并由SD卡存储;软件上下位机利用AVR单片机的输入捕捉,PWM,SPI等功能,上位机界面用LabVIEW编写,友好方便。通过对其工作性能的测试,证明了该应变仪精度高、电路简单、抗干扰能力强等优点。