基于特征选择和协同模糊聚类的模糊建模研究

为了提高模糊模型辨识效率,提出了一种新的模糊模型建摸方法,该方法由两步组成：（1）采用基于特征相似性的特征选择方法,去除原始数据的冗余;（2）利用协同模糊聚类与G-K相结合的算法初始化模糊模型,使其前件和后件参数得到优化。采用该算法对有效的特征进行协同模糊聚类,模型参数得到改善,提高了模糊模型辨识的效率。模糊建模的实验结果表明了该方法的有效性。     

关于Web Page的语义挖掘研究

关于Web Page语义挖掘的目的主要是在现有网络挖掘的基础上对挖掘内容加上语义的表述从而达到提高挖掘的效果.主要先处理挖掘的数据源,然后对数据进行语义标注,建立本体,将本体实例化,形成语义数据库,利用现有的挖掘算法实现挖掘结果.最终得到相对于现有挖掘效果得到提高的结论.     

Design program for multi-story structures

An efficient and short computer program, STFRD, has been developed to facilitate the structural engineer who is involved in multi-story building design. The program consists of three basic parts. The first part of the program performs a preliminary analysis of a frame section of a building using approximate methods to determine forces due to the loads. The loads will consist of uniform dead, live and wind loads. The second part of the program utilizes an iterative process, using the allowable stresses given by the AISC building specifications, to determine member sizes. The third part of the program consists of a matrix analysis of the frame section to determine actual forces on the members, due to the loads. This analysis is used in conjunction with the AISC building codes to verify the adequacy of the member sizes chosen. The program also has a redesign capability which is used if the preliminary member sizes are not adequate. The entire procedure has been programmed for use on a UNIVAC 1108 computer, FORTRAN IV language. The program may be obtained from the author.     

Adaptive Routing Using a Virtual Waiting Time Technique

The virtual waiting time technique is introduced as a solution to the problem of a controller distributing work to servers of different speeds. The servers are considered to be part of a distributed system without feedback. The virtual waiting time technique is shown to minimize the average completion time for a job distributed by the controller. The virtual waiting time technique does not depend on any arrival distribution and is applicable to any service time distribution. The performance of the technique is examined for different arrival and service time distributions.     

Using a fuzzy approach to support financial analysis in the corporate acquisition process

In the global market place, many companies have had to adapt their strategies to meet significant challenges. A strategy adopted by some companies has been international expansion via acquisitions. The need for expert knowledge to determine an appropriate company to acquire has been complicated by the sheer size of the global market place. The costs associated with this in relation to time and personnel have created the need for a computerised expert system to be developed. This paper endeavours to show how a proposed fuzzy based system can assist in the identification of a company for acquisition. The authors discuss the manipulation of the magnitude of fuzzy membership functions to communicate priorities within the system. The fuzzy system is designed to assist financial experts in identifying a suitable company for acquisition in the corporate acquisition process. This includes the deliberate weighting of certain inputs and results above others in the decision-making process. The system attempts to learn and simulate the human precedence given to particular financial statistics in company analysis. The system uses the magnitude of the fuzzy membership functions to reflect the human precedence given to each financial ratio. This enables a particular company's strengths and weakness to be considered while concurrently considering their significance and relevance to the acquiring organisation. The system will enable a larger number of companies to be analysed in a more time and cost-effective manner. The development of this system is intended to illustrate that a fuzzy system can aid the financial experts of an acquiring organisation in the global acquisition process.     

Performance characteristics of a broadband PC LAN: an experimental study

An experimental study has been carried out to evaluate the performance of a broadband PC LAN: the IBM PC Network. The network is subjected to tests with varying loads using artificially generated traffic from workstations. The tests span from the region of high performance to the heavy overload limits where performance is degraded. The throughput and delay characteristics are quantified with varying packet lengths and offered loads. The throughput shows a stable behaviour in the heavy overload region where packet collisions are bounded to be about 2.5 collisions/successful packet transmission. Packet delay is minimal at light load but rises sharply when the throughput saturates. The CSMA/CD protocol is seen to be fair to all contenders. The measurements are compared to predictions of existing analytical models. The result shows a close agreement with the advanced slotted model.     

Virtual sensors design for active fault tolerant control system applied to a winding machine

This paper presents a method for designing a virtual sensor in the case of Fault Tolerant Control. The whole approach, described in the paper, is applied to a winding machine. The process is modelled by a Linear Time Varying (LTV) model. The control of the web tension is based on the estimated or virtual measurements as feedback variables. The main contribution concerns the design of an accurate bank of observers able to both isolate and estimate sensor faults while preserving the system’s integrity in terms of structure and performances. The objective of Active Fault Tolerant Control System, is to maintain current performances close to desirable ones and preserve stability conditions when faults occur. The presented method allows one to isolate and to estimate sensor faults. The effectiveness and performances of the strategy are illustrated on the winding machine in the case of a complete loss of sensor.     

客车空气弹簧悬架边界条件模拟与试验验证

针对客车车架强度分析时空气弹簧悬架边界条件难以设置的问题,提出使用等效静态载荷法进行悬架模拟的思路。分析空气弹簧刚度的非线性和双横臂独立悬架的机构模型,建立整车多体动力学模型,计算多工况下车架与空气弹簧悬架连接位置处的受力,求解得到等效静态载荷并施加到有限元模型中,添加辅助约束完成边界条件设置;对车架进行多工况下的强度分析,比较不同工况下车架的应力分布和最大应力出现的位置。搭建试制样机的动态测试平台,对比仿真结果与试验结果,验证模拟方法的有效性。     

A pilot project for migrating COBOL code to web services

This paper describes a pilot project conducted to test the feasibility of constructing web services from existing mainframe COBOL programs. The project involved the use of four tools. The first tool, COBAudit, was intended to identify candidates for web services. The second tool, COBStrip, served to extract only that portion of the code required to fulfill the service. The third tool, COBWrap, wrapped the code extracted from original code and converted it to an executable component. The fourth tool, COBLink, connected the wrapped component to the web by generating a WSDL interface from either the COBOL linkage section or the original map definition. The tools were applied to a legacy life insurance system with more than 20 million lines of COBOL code running under IMS on the IBM mainframe.     

Detection of anomalous behavior in a robot system based on deep learning elements

The preprocessing procedure for anomalous behavior of robot system elements is proposed in the paper. It uses a special kind of a neural network called an autoencoder to solve two problems. The first problem is to decrease the dimensionality of the training data using the autoencoder to calculate the Mahalanobis distance, which can be viewed as one of the best metrics to detect the anomalous behavior of robots or sensors in the robot systems. The second problem is to apply the autoencoder to transfer learning. The autoencoder is trained by means of the target data which corresponds to the extreme operational conditions of the robot system. The source data containing the normal and anomalous observations derived from the normal operation conditions is reconstructed to the target data using the trained autoencoder. The reconstructed source data is used to define a optimal threshold for making decision on the anomaly of the observation based on the Mahalanobis distance.     

故障树分析中底事件排序问题的研究

基于BDD的故障树分析方法是先将故障树转换为BDD,而后进行分析.在转换的过程中,底事件的排序尤其重要,直接影响到后面的分析.研究了底事件的排序问题,将运用于数字电路的化简方法运用底事件的排序中,实例证明,可使转换后的BDD结点数比采用随机的底事件顺序产生的BDD的结点数减少一半以上,甚至可以减少到最少.     

Adaptive control for output feedback nonlinear systems in the presence of modeling errors

The paper is extending output feedback nonlinear control and backstepping approaches to a class of systems approximately diffeomorphic to output feedback systems that include unknown functions. The unknown functions are addressed via online function approximation, which results in two types of uncertainty. Parametric uncertainty due to online function approximation and non-parametric uncertainty. The non-parametric uncertainty results from the inability of any function approximator to perfectly model an unknown function and from terms unmodeled by the output feedback form. The non-parametric terms are assumed to be bounded by unknown constants. The backstepping procedure is applied to adapt with respect to both parametric uncertainties and the upper bound on the non-parametric uncertainties.     

Software tools for micro-analysis of programs

The paper proposes and describes several tools enabling their user to estimate the efficiency of Pascal or C-like programs. The approach consists of generating symbolic formulas expressing the efficiency of the programs being analyzed. The formulas are applicable to a variety of compiler-machine configurations. The actual numeric values of the variables in the symbolic formula are determined using linear programming techniques. The proposed approach reduces considerably the amount of benchmarking needed to analyze programs. Several examples are presented showing the applicability of the tools. The effort necessary to implement them is considerably reduced by the combined usage of Prolog and a symbolic formula manipulation package (Maple).     

测量用视觉传感器的自动聚焦

研究了一种新型测量用视觉传感器自动聚焦的实现,采用灰度变化率之和清晰度评价函数对被测物体进行大范围的粗聚焦,利用Roberts梯度函数实现在峰值附近的精确聚焦,并由计算机串口发控制命令驱动电机转动镜头至对焦清楚的位置。该系统具有简单实用、可靠等优点。仿真实验结果表明:自动聚焦的效果具有很好的准确度,能够满足系统的要求。     

减摇水舱试验台架系统PID控制算法的研究与实现

船舶减摇水舱试验台架是研究和设计减摇水舱的重要试验设备，准确模拟船舶在海浪中的运动是设计试验台架的关键。本系统用电液力矩伺服控制系统来模拟海浪力矩，采用PID算法进行控制，其仿真结果符合要求。     

提高车辆安全性的输出反馈自适应控制

研究含有时变参数的车辆动力学模型的输出跟踪控制问题.控制目标是使车辆的横摆角速度和质心侧偏角分别跟踪理想的设定值,通过反推方法设计输出反馈自适应控制器.控制器的输出为主动横摆力矩,通过控制主动横摆力矩来控制车辆的输出响应跟踪理想的输出信号,从而提高车辆的安全性.仿真结果表明,该控制器能更好地适应车速和路况的变化,鲁棒性强.     

Measurement of residual stresses in a plate using a vibrationaltechnique-application to electrolytic nickel coatings

A vibration method for the evaluation of the stress in a membrane is presented. The principle is based on the shift of the eigenfrequency of the modes due to the stress. The identification of the modes is obtained by an optical technique. The proposed method is applied to electrolytic nickel coatings. The results are compared with those obtained by X-ray analysis. The application of this type of measurement to other structures is discussed     

Inverse Dyamics of Non-Minimum Phase Systems with Non-Zero Initial Conditions

A method is presented forcomputing the inverse dynamics of a linear non-minimum phasesystem with non-zero initial conditions. The method is also usedto change or correct a trajectory after it is already in motion,and consequently, it will allow for real time control by continuallyupdating the inverse dynamics computation.Frequency domain techniques are used to compute the input functionneeded to produce a desired output trajectory at a particulardegree of freedom. An output profile based on the differencebetween the desired trajectory and either a homogeneous responseor a forced response to a previous forcing function is used tocompute the required input function. The resulting input functionactively damps out initial conditions in the system and makesit track the desired trajectory.The method is applied to a non-collocated single-link flexiblerobot arm. The finite element method using Timoshenko beam theoryis used to discretize the equations of motion. Torque profilesare computed to control the tip displacement for several problems.The first problem is to control the tip to a desired trajectorywhen starting with non-zero initial conditions. The second problemis to change the desired trajectory while the previous desiredtrajectory is already in motion. The third problem is to correctthe trajectory after a disturbance is added to the system. Thefourth problem is to analyze sensitivity to errors in the modeland initial conditions. The last problem is to compare tip responsesfor rigid and flexible link assumptions in the inverse dynamicscomputation.     

企业级网络虚拟映射带宽与能耗优化平衡策略

利用现有的网络环境运行大规模数据分析和处理任务是企业当前的实际需求。满足需求的途径之一是网络虚拟化技术。相比于云平台虚拟网络映射以最大化收益为出发点,企业级网络虚拟映射要以降低运行费用为目标,同时考虑节点间链路的带宽小的特点。以能源和带宽消耗优化为目标,建立了整数线性规划模型,第一步确定虚拟节点和链路映射到底层物理节点和链路的位置,第二步确定采用哪条链路传输所需镜像。实验参数来源于实际值,分析了单一优化模型和本文模型在实验数值上的差异,最终证明本文模型可以在带宽消耗优化和能耗消耗优化取得较好的平衡。     

精密排线系统的设计方法研究

根据绕线机的精密排线要求,设计了一种三闭环的排线系统,该排线系统由位置环、速度环和电流环组成。位置环用来将给定位置和电机实际反馈位置比较,通过滚轴丝杠完成张力支撑部分的排线移动工作,以达到最小误差要求。速度环根据收线架的给定速度计算排线运行系统的速度,结合反馈量实时调节电机电流,即电机速度。速度环的速度决定了整个系统的动态响应速度。电流环主要用来计算电机传动的力矩,可以根据提前保存的电机数据自动优化设置参数;该系统利用高精度的编码器构成位置闭合回路,该系统具有两个同步运行的排线平移系统,为张力支撑部分的排线平移系统和放线轮的排线平移系统。经实验验证,该控制系统两个平移系统同步性能好,密排效果满足技术要求。