基于角色的仿真动态建模研究

提出的基于角色的仿真建模方法,详细论述了该方法的建模过程与步骤,阐述了利用角色来达成建模的本质。典型仿真应用表明,该方法在建立仿真动态模型方面是有效可行的,且其具有良好的通用性、封装性、异步并发性及多分辨率特性,能够很好地解决日益复杂的仿真动态模型的建模问题。     

对网络教学的几点思考

随着网络技术、多媒体技术的发展,网络教学已经成为一种重要的教学形式,如何正确把握网络教学的模式,抓住特点,准确定位教师在网络教学中的角色,上好每一堂课,应该是每一位老师考虑的问题。     

灭火救援视景仿真中三维虚拟消防队员的设计与实现

灾害场景视景仿真是灭火救援计算机模拟训练系统的重要组成部分。而对于灾害场景中人的行为描述,特别是消防指战员组织实施灭火救援行动的描述是灾害场景表现的重要方面。从开发工具、角色建模、格式转化和骨骼动画等方面入手,就如何在灭火救援视景仿真中创建虚拟消防队员展开研究。结论表明：通过3dsMAX进行角色建模,通过Cal3D实现骨骼驱动的办法是实现三维虚拟消防队员的一个可行方案。     

Groebner基下分离子插值函数模型

给出Groebner基下建立分离子插值函数模型的方法。对于任意离散时间序列可在字典序下找到相关分离子,并用此分离子构建该离散时间序列的函数模型,及其满足所给点列的多元插值函数。通过实例说明了模型建立过程。     

Models of sensor operations for border surveillance

This article is motivated by the diverse array of border threats, ranging from terrorists to arms dealers and human traffickers. We consider a moving sensor that patrols a certain section of a border with the objective to detect infiltrators who attempt to penetrate that section. Infiltrators arrive according to a Poisson process along the border with a specified distribution of arrival location, and disappear a random amount of time after their arrival. The measures of effectiveness are the target (infiltrator) detection rate and the time elapsed from target arrival to target detection. We study two types of sensor trajectories that have constant endpoints, are periodic, and maintain constant speed: (1) a sensor that jumps instantaneously from the endpoint back to the starting‐point, and (2) a sensor that moves continuously back and forth. The controlled parameters (decision variables) are the starting and end points of the patrolled sector and the velocity of the sensor. General properties of these trajectories are investigated. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

Fitting Lanchester equations to the battles of Kursk and Ardennes

Lanchester equations and their extensions are widely used to calculate attrition in models of warfare. This paper examines how Lanchester models fit detailed daily data on the battles of Kursk and Ardennes. The data on Kursk, often called the greatest tank battle in history, was only recently made available. A new approach is used to find the optimal parameter values and gain an understanding of how well various parameter combinations explain the battles. It turns out that a variety of Lanchester models fit the data about as well. This explains why previous studies on Ardennes, using different minimization techniques and data formulations, have found disparate optimal fits. We also find that none of the basic Lanchester laws (i.e., square, linear, and logarithmic) fit the data particularly well or consistently perform better than the others. This means that it does not matter which of these laws you use, for with the right coefficients you will get about the same result. Furthermore, no constant attrition coefficient Lanchester law fits very well. The failure to find a good‐fitting Lanchester model suggests that it may be beneficial to look for new ways to model highly aggregated attrition. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

基于正交试验设计的内燃机缸套和活塞环磨合过程数学模型的建立

在对内燃机缸套和活塞环磨合过程进行试验研究的基础上,提出了基于正交试验设计的内燃机缸套-活塞环磨合过程磨损量和磨合时间的数学模型,并对试验结果进行了多元正交多项式回归分析,进而利用磨合过程的数学模型分析了各影响因素对磨合过程的影响.磨合模型的建立对确定合理的磨合时间和磨合规范,提供了理论和方法的依据.     

Using a birth‐and‐death process to estimate the steady‐state distribution of a periodic queue

If the number of customers in a queueing system as a function of time has a proper limiting steady‐state distribution, then that steady‐state distribution can be estimated from system data by fitting a general stationary birth‐and‐death (BD) process model to the data and solving for its steady‐state distribution using the familiar local‐balance steady‐state equation for BD processes, even if the actual process is not a BD process. We show that this indirect way to estimate the steady‐state distribution can be effective for periodic queues, because the fitted birth and death rates often have special structure allowing them to be estimated efficiently by fitting parametric functions with only a few parameters, for example, 2. We focus on the multiserver M_t/GI/s queue with a nonhomogeneous Poisson arrival process having a periodic time‐varying rate function. We establish properties of its steady‐state distribution and fitted BD rates. We also show that the fitted BD rates can be a useful diagnostic tool to see if an M_t/GI/s model is appropriate for a complex queueing system. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 664–685, 2015     

FORECASTING SERIES CONTAINING OFFSETTING BREAKS: OLD SCHOOL AND NEW SCHOOL METHODS OF FORECASTING TRANSNATIONAL TERRORISM

Transnational terrorism data are difficult to forecast because they contain an unknown number of structural breaks of unknown functional form. The rise of religious fundamentalism, the demise of the Soviet Union, and the rise of al Qaeda have changed the nature of transnational terrorism. ‘Old School’ forecasting methods simply smooth or difference the data. ‘New School’ methods use estimated break dates to control for regime shifts when forecasting. We compare the various forecasting methods using a Monte Carlo study with data containing different types of breaks. The study's results are used to forecast various types of transnational terrorist incidents.     

The impact of defense and non‐defense public spending on growth in Asia and Latin America∗

For a three‐sector Feder‐Ram framework, we present time‐series, cross‐sectional estimates for two cohorts, consisting of Asian and Latin American countries. The estimates indicate that private investment, and defense and non‐defense public spending are growth promoting for alternative error components representations. For the best error components representation, greater growth enhancement is associated with the two forms of public spending in Asia than in Latin America, while the opposite comparison characterizes private investment. Although defense is growth promoting, an opportunity cost exists insofar as non‐defense spending, financed by defense spending, appears to give a small net boost to growth in Latin America.