Implementation of a TMO‐structured real‐time airplane‐landing simulator on a distributed computing environment

In real‐time simulation, the simulated system should display the same (or very close) timing behavior as the target system. The simulation accuracy is increased as the simulation time unit is decreased. Although there are several models for such systems, the TMO model is particularly appropriate due to its natural support for real‐time distributed object‐oriented programming. This paper discusses the results of the implementation of a real‐time airplane‐landing simulator on a distributed computing environment using the TMO model. Copyright © 2004 John Wiley & Sons, Ltd.     

A comparison between classical robust stability conditions

The paper is focused on the comparison between some classical robust stability conditions for continuous‐time linear time‐invariant systems. Such conditions are given as lemmas in the paper, since their statements include some generalizations, needed in order to better compare (and use) them. The analysis is carried out by comparing pairwise the families of systems whose stabilization through a given compensator is guaranteed by each of the considered robust stability conditions. Some properties of the families are formally derived and stated, and some very simple examples arc exhibited in order to illustrate the presented properties and comparisons. A theorem, representing an extension of one of the considered conditions, is proposed in order to overcome some difficulties arising in the use of the classical result. Copyright © 2004 John Wiley & Sons, Ltd.     

A nonlinear minimization approach to multiobjective and structured controls for discrete‐time systems

In this paper, a nonlinear minimization approach is proposed for multiobjective and structured controls for discrete‐time systems. The problem of finding multiobjective and structured controls for discrete‐time systems is represented as a quadratic matrix inequality problem. It is shown that the problem is reduced to a nonlinear minimization problem that has a concave objective function and linear matrix inequality constraints. An algorithm for the nonlinear minimization problem is proposed, which is easily implemented with existing semidefinite programming algorithms. The validity of the proposed algorithm is illustrated by comparisons with existing methods. In addition, applications of this work are demonstrated via numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.     

弧齿锥齿轮铣齿机切削系统时序辨识

为了提高弧齿轮加工精度和切齿效率，提出弧齿锥齿轮铣齿机切削系统的时序分时建模系统辨识方法，通过对Y2250型铣齿机工件主轴垂直和水平方向的振动测试，应用研制开发的时间序列分时建模程序包，得出该机床固定安装法的切削系统模型，并进行了模态分析及时序谱分析。噪声方差很小，辨识结果具有较高的可信度。     

PVTt法气体流量标准装置中标定时间的确定

PVTt法气体流量标准装置是测量气体质量流量的一种高精度标准装置,通过测量装置中标准容器内充气前后的气体压力、温度来确定流过被检表的气体实际质量流量值.该气动系统中的充气过程是热力变化和传热变化的复杂过程.该文运用热力学、气体动力学中喷管及激波理论,研究了标定时间理论值的计算,并进行了实例分析.研究表明启动段时间对测量精度影响甚微,而充气过程中的多变指数n及控制元件(喷管)的选用对测量精度影响较大.     

基于多维空间的商务协同要素分析

运用四维空间分析方法,引入时间压缩策略、战略成本管理、标杆管理和协同效应等原理,将网络协同商务链置于时间维、经济成本维、性能维和可持续发展维等多维空间中进行多元素分析和运筹。指出企业间资源、信息与业务的协同能力依赖于时间、成本、性能以及持续竞争优势等多个约束因素的协调。     

平稳时间序列高斯性检验的积分多谱方法

利用积分多谱给出了一种平稳时间序列的高斯性检验方法,并通过仿真实验进行了验证。     

机械维修性的数量特征

维修性是机械设备的一个重要特性。就其数学模型、维修时间的分布与参数、维修周期的确定及维修性分配等问题进行定量分析 ,以便更合理地进行机械设备维修决策和设计     

A heuristic algorithm for the just-in-time single machine scheduling problem with setups: a comparison with simulated annealing

This paper addresses the single machine early/tardy problem with unrestricted common due date and sequence-dependent setup times. Two algorithms are introduced to reach near-optimum solutions: the SAPT, a heuristic tailored for the problem, and a simulated annealing (SA) algorithm. It will be shown that SA provides solutions with slightly better quality; however, SAPT requires much less computational time. SAPT-SA is a hybrid heuristic that combines both approaches to obtain high quality solutions with low computational cost. Solutions provided by the three algorithms were compared to optimal solutions for problems with up to 25 jobs and to each other for larger problems.     

Estimation of Incubation Time of Cavitation Erosion for Various Cavitating Conditions

Estimations have been made, resulting in a general method for the prediction of the incubation time for cavitation erosion using various cavitating conditions and materials. From a single erosion test, the incubation time can be estimated for various conditions and materials by plotting the mass loss as a function of exposure time to cavitation on a log–log scale.