恶劣环境对船舶焊接的影响

在船舶建造过程中焊接工作量约占全部的30%~40%，焊接是保证质量的重中之重。焊接质量出问题，就可能造成严重的后果。我厂沿江堤而建，空气中湿度大，工作条件差。密集性气孔很严重。所以，在这种情况下，对我厂焊接质量控制提出更高的要求。     

不确定环境下的地震应急救援路径优化研究

针对地震应急救援的特点,引入不确定理论,在地震灾害的背景下,研究震后动态网络环境下的应急救援路径选择问题。用不确定变量表示网络中各路段的破坏程度,综合考虑路径破坏程度及车辆路径连续性等约束条件,以救援时间最短为目标,基于不确定理论建立了动态优化模型,并用改进的遗传算法求解,最后设计算例验证了模型和算法的有效性。     

What is extreme about Mises’s extreme apriorism?

There is something extreme about Ludwig von Mises’s methodological apriorism, namely, his epistemological justification of the a priori element(s) of economic theory. His critics have long recognized and attacked the extremeness of Mises’s epistemology of a priori knowledge. However, several of his defenders have neglected what is (and what has long been recognized by his critics to be) extreme about Mises’s apriorism. Thus, the argument is directed less against Mises than against those contributions to the secondary literature that assert his methodological moderation while overlooking what the most prominent critics have found extreme about Mises’s apriorism. Defending Mises as a merely moderate apriorist because he held only a narrow part of the foundation of economics to be a priori is a straw-man defense against criticisms of his apriorism as epistemologically extreme.     

Searching for empirical linkages between demographic structure and economic growth

Demographic structure could affect economic growth through many channels. However, little is known about how demographic structure affects economic growth since no study has examined an extensive collection of channels through which demographic structure could affect economic growth in a single context. This paper overcomes this limitation by examining 45 potential mediating variables between demographic structure and economic growth. A causal search algorithm is used to identify channels through which demographic structure affects economic growth. Our results suggest that demographic structure affects economic growth differently between developed and developing countries. For developed countries, we find that an increase in the share of middle-aged workers has a positive effect on economic growth through institutions, investment and education channels. On the other hand, an increase in the share of the senior population has a negative effect on economic growth through institutions and investment channels. For developing countries, we find (but with weak evidence) that an increase in the share of young workers has a negative effect on economic growth through investment, financial market development and trade channels.     

上市公司“MD&A”信息质量评价模型——基于政府监管的视角

管理层讨论与分析(Management’s Discussion and Analysis,MDA)作为财务报表的有益补充,因其能够有助于增强信息披露的针对性和有效性而越来越受到信息使用者的关注。针对我国MDA信息质量不高的现状和评价体系不尽完善的情况,总结和吸收前人的研究成果,合理界定MDA信息质量特征。在此基础上,充分考虑MDA信息的生成机制和外部评价结果,采用层次分析法,构建适合我国上市公司MDA信息质量评价模型。     

基于成本优化的制造业生产物流装配线排序问题分析

为了降低制造业的生产成本，提高收益，在分析生产物流配线闲置和超载成本的基础上，采用粒子群算法对其进行优化，并利用模糊自适应改进惯性权值，通过实证研究表明该方法实用，可操作性强，可以有效降低制造业生产物流成本，具有广泛的应用价值。     

Numerical Maximisation of Likelihood: A Neglected Alternative to EM?

There is by now a long tradition of using the EM algorithm to find maximum‐likelihood estimates (MLEs) when the data are incomplete in any of a wide range of ways, even when the observed‐data likelihood can easily be evaluated and numerical maximisation of that likelihood is available as a conceptually simple route to the MLEs. It is rare in the literature to see numerical maximisation employed if EM is possible. But with excellent general‐purpose numerical optimisers now available free, there is no longer any reason, as a matter of course, to avoid direct numerical maximisation of likelihood. In this tutorial, I present seven examples of models in which numerical maximisation of likelihood appears to have some advantages over the use of EM as a route to MLEs. The mathematical and coding effort is minimal, as there is no need to derive and code the E and M steps, only a likelihood evaluator. In all the examples, the unconstrained optimiser nlm available in R is used, and transformations are used to impose constraints on parameters. I suggest therefore that the following question be asked of proposed new applications of EM: Can the MLEs be found more simply and directly by using a general‐purpose numerical optimiser?     

The trade-off between fixed vehicle costs and time-dependent arrival penalties in a routing problem

This paper introduces the vehicle routing problem with soft time windows (VRPSTW) in which problem definition differs from ones previously defined in literature. Branch-and-price approach is employed, resulting in a set partitioning master problem and its new subproblem. Novel techniques are consequently developed to solve this new subproblem. Experimental results report the comparisons of these solution techniques under the branch-and-price framework. The VRPSTW solutions have further been compared to the state-of-the-art literature, signifying the superiority of the VRPSTW on this issue.     

基于遗传算法的锅炉水位控制器设计

文章分析了锅炉水位控制系统的基本原理及结构,针对传统PID控制器的不足之处设计了基于遗传算法的新型锅炉水位控制器,在此基础上搭建了锅炉水位控制系统。最后,通过仿真验证了该水位控制器在改善水位系统稳态误差及动态超调方面均具有较好的作用。     

Food industry structure in Norway and Denmark since the 1990s: Path dependency and institutional trajectories in Nordic food markets

Structural changes in Norwegian and Danish food industry since the 1990s is analysed as a path dependent response to the neo-liberal turn. Norway entered the 1990s as a protected market and Denmark as case of an export oriented industry. These developmental strategies are rooted in early 20th century industrialisation and influenced by institutional transformations in the 1990s, such as EU and WTO. Mergers and acquisitions (M&A) are studied in the context of changing political environments. Explaining two different trajectories, we combine path dependency theories and a Polanyi inspired ‘varieties of capitalism’ framework with corporate strategy theories on food industry M&As. We identify two different types of path dependent development, a self-reinforcing in Denmark and a transformative ‘breaking point’ in Norway.