大空间飞机修理厂房分层空调的可行性分析

本文以某大空间飞机修理厂房为研究对象,采用Airpak软件对其原始分层空调设计方案气流组织进行模拟,并对方案可行性进行评价。     

Making Good Decisions with Minimal Information: Simultaneous and Sequential Choice

The adaptive pressures facing humans and other animals to make decisions quickly can be met both by increasing internal information-processing speed and by minimizing the amount of information to be used. Here we focus on the latter effect and ask how, and how well, agents can make good decisions with a minimal amount of information, using two specific tasks as examples. When a choice must be made between simultaneously-available options, minimal information in the form of binary recognition (whether or not each item is recognized) can be used in the recognition heuristic to choose effectively. When options are encountered sequentially one at a time, minimal information as to whether or not each option is the best encountered so far is sufficient to guide agents using a simple search-cutoff rule to high performance along several choice criteria. Both of these examples have important economic as well as biological applications, and show the power of simple fast and frugal heuristics to produce good decisions with little information. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the performance of the Chow-Lin procedure for quarterly interpolation of annual data: Some Monte-Carlo analysis

Most of the countries of the OECD offer quarterly estimates of their national growth or of their Gross National Product. Official Statistical Agencies in western countries have to deal with the problem of estimating Quarterly National Accounts series congruently with Annual National Accounts. In Spain, the Instituto Nacional de Estadística uses the Chow-Lin disaggregation method, which is based on information provided by a group of high-frequency related variables, to estimate the quarterly components of National Accounts from annual components. In this paper, we analyse the relative quality of the estimates obtained through the Chow-Lin procedure, under different sets of hypotheses.JEL Classification: C15, C43, M40We are grateful to Maria Amparo Ripoll for her assistance. The authors also wish to thank three anonymous referees and an editor for their constructive suggestions and comments. This research was partially made during the stay of the first author at the Universidad Carlos III de Madrid. It has been partially supported by the research project DGCYT PB98-1460.     

Futures beyond dystopia

The speculative imagination is an higher-order human capacity that can productively explore the not-here and the not-yet. To some extent it is already doing so. But these explorations are limited by prevailing cultural assumptions. The purpose of this paper is to suggest that there are other arenas to explore that, were they taken seriously, could exert sufficient symbolic ‘pull' to qualify as desirable images of futures. They could then begin to act as ‘magnets' for the realisation of possibilities that are presently obscured.     

Investment planning under uncertainty and flexibility: the case of a purchasable sales contract*

Investment decisions are not only characterised by irreversibility and uncertainty but also by flexibility with regard to the timing of the investment. This paper describes how stochastic simulation can be successfully integrated into a backward recursive programming approach in the context of flexible investment planning. We apply this hybrid approach to a marketing question from primary production which can be viewed as an investment problem: should grain farmers purchase sales contracts which guarantee fixed product prices over the next 10 years? The model results support the conclusion from dynamic investment theory that it is essential to take simultaneously account of uncertainty and flexibility.     

一类多机种飞机油料加注问题的仿真研究

总结了国内相关人员关于作战飞机地面油料加注的研究,借助GPSSW仿真语言研究了多机种飞机单队列、多服务台、服务台可休假的油料加注模型,并在给定设施利用率范围的条件下得到科学合理的服务台数量分配结果。     

3R02型减速器箱体振动特性的数值模拟分析

为研究3R02型减速器工作振动特性,利用ANSYS软件对减速器箱体进行有限元建模,并对其进行静力学计算和模态分析。结果表明:工作过程中最大变形出现在最大轴承孔与中间轴承孔的连接处。在箱体x方向,箱体的振动产生的位移从两侧端向最大轴承孔表现出由小到大的趋势。从第六阶模态开始,箱体不易产生共振;而在低频区,当外界的激励频率与其自然频率一致时,箱体会承受较大的应力。箱体在X、Z方向存在振动,在优化设计过程中应适当增加刚度和阻尼来抑制此类振动的影响。     

提高会计模拟实验教学质量的思考

会计作为一门应用性学科,加强会计模拟实验教学很有必要。会计模拟实验教学应用于会计教学中,可以加深学生对会计专业课程的理解,激发学生的学习兴趣,有利于提高会计教学质量。     

A New Internet Driven Internationalisation Framework

This paper aims to offer a new Internet driven theoretical framework that explains how a successful internationalisation process may be developed and identifies the strategic dimensions that influence the key decisions in an interrelated, performance-associated way. The extant literature is examined in international marketing, international entrepreneurship and Internet marketing and a comprehensive strategic analysis is conducted of a successful individual services business: ING Direct. It is shown how strategic constructs and risk constructs drive the internationalisation process in an interrelated and performance-associated way. In the framework, the firm's target is to take advantage of an opportunity by obtaining a sustainable competitive advantage while attenuating international risk. Entry mode and country selection are strategic decisions interrelated mutually and with other strategic choices and with performance; this is why an analysis with ceteris paribus statements or episodic analysis may lead to the wrong conclusions.     

A Comparison of Two Quadratic Approaches to Hedging in Incomplete Markets

This paper provides comparative theoretical and numerical results on risks, values, and hedging strategies for local risk-minimization versus mean-variance hedging in a class of stochastic volatility models. We explain the theory for both hedging approaches in a general framework, specialize to a Markovian situation, and analyze in detail variants of the well-known Heston (1993) and Stein and Stein (1991) stochastic volatility models. Numerical results are obtained mainly by PDE and simulation methods. In addition, we take special care to check that all of our examples do satisfy the conditions required by the general theory.