基于虚拟现实技术的救助船对外消防培训仿真系统

针对救助船消防训练中存在的海况复杂,对外消防炮射流受风影响大,往往无法准确控制其射向目标区域的问题,在理想状态下射流理论的基础上探究风对射流轨迹的影响,建立自然风条件下射流轨迹的数学模型,模拟对外消防炮射流的运动情况。应用3ds Max构建船舶模型,用Unity3D构建救助船在面临大风浪、遇险船着火等状况时对外消防系统的工作场景,提出一种精确构建粒子系统轨迹的方法,使射流模型能精确体现在场景中。通过虚拟现实设备能实现救助船对外消防培训仿真系统的立体显示和人机交互,起到更好的虚拟仿真和培训效果。     

MATLAB在控制系统稳态误差分析中的应用

本文分析说明了如何利用MATLAB实现控制系统稳态误差的计算及稳态误差曲线的绘制,并通过一个控制系统实例做了详细介绍。     

基于船舶航行仿真的吴淞口建闸方案优化

为评价吴淞口3个建闸方案的可行性,提出一种基于船舶航行仿真的建闸方案选优方法.通过观测和分析黄浦江交通流情况,选出恰当的代表船型并搜集代表船型的船舶资料建立船舶操纵模型,制作电子海图.根据水文气象信息设计各仿真试验方案,在考虑船舶习惯航法的基础上进行单船及大小船交会的仿真试验;分析重要指标,如航道宽度、转向角等,确定推荐方案并在此基础上进行优化.该方法能为吴淞口建闸方案的确定提供科学依据,可作为评价比选建闸方案的有效新途径.     

区域岩浆热液成矿的数值模拟——以熊耳山前河地区金矿为例

熊耳山前河地区金矿是熊耳山地区具有代表性的金矿之一,位于华北克拉通南缘,是中国重要的黄金产区。该金矿是典型的构造蚀变岩型金矿,成矿流体以岩浆水为主,成矿物质来源以深部幔源为主,属中低温热液矿床。以熊耳山前河金矿为例,搭建区域成矿的二维地质模型,分别进行稳态与瞬态数值模拟分析。结果显示：在合理的岩体和断层参数条件下,来自岩浆的高温成矿流体沿断裂带流动,加热断层及其围岩,可以达到成矿需要的温度和压力。热液成矿的主要影响因素是热液在断层带中流过携带的物质和热量。流体传递的总热量与断层宽度、热液源头的流体温度压力、断层渗透率的大小等有关。断层渗透率越高、源头压力越大、温度越高,断层内的热液流速就越大、平流传递的热流密度就越大;在同样热流密度下,如果断层越宽,则传输的总热量越大,更有利于在较短的时间段内,达到在特定压力下利于金矿生成的温度,形成金矿。在这些影响因素中,由于断层带的渗透率可以变化几个数量级,它的影响尤为显著。当断层渗透率较低时,前河地区热液成矿系统达到稳定的适合成矿条件需要~1 Ma;而断层渗透率较高时,只需要千年尺度就可以达到稳定的适合成矿的温压条件。     

Socio- and Psycholinguistic Considerations in Interactive Video Instruction for Limited English Proficient Students

No abstract available for this article.     

Motor control of practice and actual strokes by professional and amateur golfers differ but feature a distance-dependent control strategy

Abstract

We explored how practice and actual putting strokes differed between professionals and high-level golf amateurs, and how practice strokes reflected subtle differences in putting distances. We analysed swing amplitude, impact velocity, and acceleration profile of the club-head. The acceleration profiles showed that the motor control pattern of the practice stroke differed from that of the actual stroke. To clarify the effects of different putting distances on the practice stroke and to analyse how much the actual stroke could be explained by the practice stroke, we conducted individual regression analyses. The practice strokes of all participants could be divided into three strategies and five types by the coefficient of determination and the slope. This implies that the purpose of the practice stroke varied among golfers. Most golfers used the individual velocity criteria in their practice strokes, which resulted in different putting distances based on their criteria. Unexpectedly, we found no significant difference in skill level between professionals and high-level amateurs. The results of this study imply that the practice stroke does not duplicate the actual stroke, even for professional golfers with excellent skills. However, most high-level golfers adopted distance-dependent control strategies for slightly different putting distances.     

The Effect of Bilingualism on the Measured Intelligence of Elementary School Children of Italian Parentage

The recency of the community college movement has prevented large scale organization and dissemination of knowledge concerning the processes and steps required to establish a community college. There is, therefore, a need for means to incorporate contemporary evidence into the curriculum of prospective administrators of higher education. The purpose of this study was to compare Higher Education Administration students’ peceptions of a logical sequence of events for establishing a community college with a sequence of events for establishing a community college as determined by practice. The Edwards’ matched-pair technique was used to rank the perceptions of the students. A sequence of twenty-nine events was selected from the literature. Each event was matched with every other, thus providing 406 decision situations. From these decisions an ordering was obtained. Using the Spearman rho correlation technique, a coefficient of 0.82 was found between the sequence of events taken from the literature and rank ordering of these events as determined by the Edwards’ matched-pair technique.     

Cultivation of taste and bounded rationality: Some computer simulations

One can approach the economics of the arts, as any field of applied economics, in either of two ways. First, one can treat economic theory and econometric technique as subjects settled by specialists in those fields, to be used in the ec onomics of the arts as they are given, very much as if one were studying the demand for maize. Alternatively, one can treat the economics of the arts as a field which may need and suggest its own developments in theory and technique, suitable to its spec ial problems and processes, from which general economic theory and econometric theory might in principle learn something. Perhaps this latter view is implausible, given the high state of development of economic theory and econometrics in the modern liter ature. Yet many of the advances embodied in these fields have come from particular areas of application-and the economics of maize has been a particularly fertile field.I am indebted to participants in the Seventh International Conference on Cultural Economics, Fort Worth, Texas, October 1992; to p articipants in the Seminar on the Economics of the Arts, Venice, Italy, December 1992; to participants in the conference of the Pennsylvania Economists' Association, Wiles-Barre, PA, June, 1993; to participants in the second conference on Simulating Soci eties, Siena, Italy, July 1993; to participants in the conference of the Society for the Advancement of Behavioral Economics, Rensselaerville, NY, August 1993; and to participants in the Third Conference on Artificial Intelligence in Economics and Manage ment, Portland, OR, August 1993, for useful comments on topics related to the research reported in this paper. Errors and omissions are, of course, attributable to the author.     

Dynamic Monte Carlo simulation of linear SAW polymer chain near a flat surface

Investigation of the conformational properties of a SAW polymer chain near an impenetrable, non-interacting flat surface showed that the chain at first contracted and orientated itself to slightly parallel when it pulled close to the surface and at last elongated and reoriented itself to slightly perpendicular to the surface at very small distance from the surface. Simulation showed that most of the disappeared configurations were of large size at moderate distance from the surface while they were of small size at very small distance from the surface; and that the mean-square end-to-end distance was much more prone to be influenced by the surface than the mean-square radius of gyration . The orientational correlation between the direction of the longest principal axis of the moment of inertia and end-to-end vector was also discussed.     

编辑加工中常见问题辨析

分析编辑加工中经常遇到的国家标准没有明确规定或容易出错的问题,如计算机仿真图的编辑加工、直径的表示方法和缩略语的使用等,并提出相应的建议.