均匀试验设计在无人机关键参数设计中的应用

针对所采用CFD软件FLUENT对无人机的气动特性数值模拟,消耗大量时间这一问题,进行了试验设计,来减少试验次数。首先对各种常见的试验设计方法的优点局限性及试验次数进行了全面而详细的分析与总结,然后选取了均匀试验设计的方法来安排试验,实践了均匀试验设计在无人机关键参数设计中应用的案例,并通过曲线拟合建立了相应的模型,对均匀试验设计的可行性进行了验证。     

多晶硅制绒中影响金字塔结构因素的研究

通过分析不同碱性溶液及添加不同活性剂制备出的具有不同金字塔结构的绒面,探讨了影响金字塔成核的因素。采用扫描电镜和紫外一可见分光光度计对绒面的金字塔结构和反射特性进行了分析,结果表明,腐蚀速率与金字塔尺寸成正比,金字塔结构影响绒面减反特性。对造成金字塔结构差异的原因和金字塔成核过程进行了分析。     

Book reviews

The Political Economy of Military Spending in the United States, Alex Mintz (ed), London and New York: Routledge, 1992, pp x, 334; ISBN 0–415–07595–5

Penser La Guerre, Penser L'Economie, Christian Schmidt, (Paris: Odile Jacob, 1991), 350p.

Military Production and Innovation in Spain, Jordi Molas‐Gallart, Chur (CH): Harwood Academic Publishers, 1992, pp. vii, 212; ISBN 3–7186–5280–3     

Introduction: Symposium on defence economics

This study revisits the relationship between defence spending and economic growth via a Keynesian model in Pakistan using the autoregressive distributive lag bounds testing approach to cointegration. Empirical evidence suggests a stable cointegration relationship between defence spending and economic growth. An increase in defence spending reduces the pace of economic growth confirming the validity of Keynesian hypothesis in this case. Current economic growth is positively linked with economic growth of previous periods while a rise in non-military expenditures boosts economic growth. Interest rate is inversely associated with economic growth. Finally, unidirectional causality running from military spending to economic growth is found.     

REGIONAL EFFECTS OF MILITARY BASE CLOSURES: THE CASE OF SWEDEN

The purpose of this paper is to investigate regional effects of military base closures in Sweden during the last decades. Our analysis is based on a regional growth model, where two equations are estimated; one equation describing the average income growth rate and one equation describing the net migration rate. The data set is a panel of 31 Swedish municipalities covering the period 1983–1998. Our main finding is that a closure of a military base has not had any significant impact on the subsequent average income growth rate nor the net migration rate in the affected municipalities. One potential explanation for these results relates to the labour market and the composition of the labour force.     

THE LONG‐RUN RELATIONSHIP BETWEEN DEFENCE EXPENDITURES AND GDP IN TAIWAN

Using the Solow–Swan growth model and the time‐trend included in the aggregate production function, this study applies the multivariate cointegration approach to re‐investigate the long‐run and causal relationships between defence expenditures and GDP while controlling for capital and labour input in Taiwan during the 1955–2002 period. It examines the long‐run causal relationship using the weak exogeneity test and utilizes general impulse response functions to determine whether a shock to defence expenditures affects economic growth or vice versa. Our findings provide substantive evidence in favour of the existence of a long‐run equilibrium cointegrated relationship between defence expenditures, GDP, labour and capital stock. The results of the weak exogeneity test indicate that a bi‐directional causal relationship exists in the long‐run between defence expenditures and GDP. Thus, the main policy implication that emerges from the long‐run results is that increasing defence expenditures in Taiwan is an effective means to boost overall economic performance and, with this improved economy, it should then be able to increase its defence expenditures further. Lastly, from our dynamic vector error correction model estimations, it is found that defence expenditures are a major means of adjusting for disequilibria that occur within the system.     

A non‐linear defence‐growth nexus? evidence from the US economy

The defense‐growth nexus is investigated empirically using time series data for the US and allowing the effect of defense spending on growth to be non‐linear. Using recently developed econometric methods involving threshold regressions, evidence of a level‐dependent effect of military expenditure on GDP growth is found: the positive externality effect of defense spending prevails for relatively lower levels of defense spending (with respect to the history of defense spending in the US) and reverts its influence for higher levels.     

Defence spending and economic growth: A causal analysis for Greece and Turkey*

There are a number of studies which consider the relation between military spending and economic growth using Granger causality techniques rather than a well‐defined economic model. Some have used samples of groups of countries, finding no consistent results. Others have focused on case studies of individual countries, which has the advantage of the researchers bringing to bear much more data than the cross country samples and a greater knowledge of the structure of the economy and the budget. This paper adds to the literature by providing an analysis of two countries, Greece and Turkey, which are particularly interesting case studies given their high military burdens, the poor relations between the two and the resulting arms race in the area. In addition to analysing the data using standard “pre‐cointegration” Granger causality techniques, this paper employs modern vector autoregressive (VAR) methodology that utilises cointegration via Granger's representation theorem. The standard Granger causality tests suggest a positive effect of changing military burden on growth for Greece, but this is not sustained when the cointegration between output and military burden is taken into account. The only evidence of significant Granger causality is a negative impact of military burden on growth in Turkey.     

A note on the causal relationship between defence spending and growth in Greece: 1955–93

The causal relationship between economic growth and defence spending has attracted considerable attention and has been the subject of many empirical studies. This paper investigates the existence of a causal link between military expenditure and economic growth in the case of Greece for the period 1955–93. By European Union standards, Greece allocates substantial human and material resources to defence. At the same time, Greece is the poorest European Union member facing chronic economic problems. Using the concept of Granger‐causality, the findings reported herein suggest that neither variable Granger‐causes the other disclosing thereof the absence of any causal ordering between them.     

互联网大数据可用性增长方式研究

随着信息技术的发展,特别是物理信息系统、互联网、社交网络等技术的突飞猛进,数据爆炸性增长的同时,劣质数据也随之而来,数据可用性受到严重影响。近年来,学术界和工业界开始研究数据可用性问题,取得了一些的研究成果,但是针对互联网大数据可用性问题的研究工作还很少。文章从大数据的发展现状分析入手,概述了大数据可用性的挑战,探讨了大数据可用性方面的研究问题。通过机器翻译案例,指出了互联网大数据可用性增长的可能途径。