周期性有耗介质结构的电磁散射研究

本文介绍一种新的涂层隐身方法:周期涂覆方法,它与均匀涂覆方法相比,能够在不增加散射体厚度的情况下,使用现有单层有耗材料,使目标的隐身特性得以较大改善。本文运用快速傅氏变换和迭代法对一些具体例子进行了计算,并与实验结果进行了比较。     

The road to business process improvement--can you get there from here?

Historically, "improvements" within the organization have been frequently attained through automation by building and installing computer systems. Material requirements planning (MRP), manufacturing resource planning II (MRP II), just-in-time (JIT), computer aided design (CAD), computer aided manufacturing (CAM), electronic data interchange (EDI), and various other TLAs (three-letter acronyms) have been used as the methods to attain business objectives. But most companies have found that installing computer software, cleaning up their data, and providing every employee with training on how to best use the systems have not resulted in the level of business improvements needed. The software systems have simply made management around the problems easier but did little to solve the basic problems. The missing element in the efforts to improve the performance of the organization has been a shift in focus from individual department improvements to cross-organizational business process improvements. This article describes how the Electric Boat Division of General Dynamics Corporation, in conjunction with the Data Systems Division, moved its focus from one of vertical organizational processes to horizontal business processes. In other words, how we got rid of the dinosaurs.     

The value of switching inputs in a biodiesel production plant

There has been a growing concern in recent years about the quality of the environment and dependence on fossil fuels to supply the world's energy needs, which has created an interest in the development of renewable and less polluting energy sources. One of these alternatives is the biodiesel fuel, which has many advantages over the fossil based diesel, or petro diesel. In this paper we use the real options approach to determine the value of the managerial flexibility embedded in a biodiesel plant that has the option to switch inputs among two different grain commodities. Our results indicate that the option to choose inputs has significant value if we assume that future prices follow stochastic processes such as Geometric Brownian Motion and Mean Reversion Models, and can be sufficient to recommend the use of input commodities that would not be optimal under traditional valuation methods. We also show that the choice of model and parameters has a significant impact on the valuation of this class of projects.     

The wealth effects of takeover bids regulation in the European Union

We investigate the wealth effects of the Takeover Bids Directive, enacted by the European Union (EU), on mergers and acquisitions. The directive aims at protecting target minority shareholders by restricting antitakeovers provisions and preventing managerial entrenchment. We test the regulation impact using a treatment sample of EU public acquisitions and a control sample from outside the EU. Our results suggest diverse effects of the regulation across treatment countries: acquirers from countries with better shareholder protection engage in more value-enhancing acquisitions postregulation that could otherwise be too costly. The regulation also increases the likelihood of firms becoming targets and raises market value.     

Volunteer Labour Supply: the role of workers' motivations

Abstract In this paper we study the determinants of volunteering. We depart from previous literature that considers only economic incentives and investigate the role that extrinsic and intrinsic motivations play in shaping the supply of voluntary labour. We build on previous theoretical research and derive a framework for interpreting results from our econometric analysis. We consider a sample of Italian workers of which we can observe proxies of motivations and volunteering choices in three different sectors: social services, political activism and union activism. We make due allowance for the endogeneity of motivations and show that both types of motivations have an effect on volunteering. Consistently with theoretical models, we find extrinsic motivations to lower voluntary labour supply, whereas the opposite holds for intrinsic motivations .     

Reducing risk factors for international visitors in destinations

This paper examines issues relating to the safety of international visitors in tourism destinations using Queensland as a case study. Safety is an important yet often neglected aspect of destination management and failure to implement strategies designed to reduce the level of risk may expose destinations to unfavorable publicity leading to erosion of domestic as well as inbound markets. Rather than take a broad perspective discussing all forms of risk, the paper focuses on motor vehicle accidents and water activities. A simple four‐step model of destination risk identification and management is developed. The paper then focuses on strategies that should be considered by the authorities and individual tourist to reduce risk in motor vehicle accidents and in water sports. The paper concludes with identification of destination risk management as an issue requiring further research.     

从“G7时代”到“G20时代”——国际金融治理机制的变迁

2008年9月,美国金融危机的爆发对世界经济构成了严重威胁,也对始于1975年以七国集团(G7)为核心的国际金融治理模式提出了严峻挑战。由于传统国际金融治理机制的失灵,已经运转了十年的二十国集团(G20)从部长级会议正式提升为首脑级会议,并且在两年的时间里召开了五次首脑峰会,开创了既有国际机制的先例。在2009年的匹兹堡峰会上,二十国集团首脑峰会被正式制度化,并被提升为治理国际金融体系最主要的制度平台。国际金融治理机制发生了从G7时代向G20时代的重大转变。此次国际金融治理机制变迁的原因在于国际经济的权力结构发生了变化,传统的治理模式难以为继,而国际金融危机的爆发加剧了传统机制的失灵。作为一种新的制度模式,二十国集团适应了国际经济权力结构的变迁,而且在节约制度建设成本上具有相当大的优势。正因如此,二十国集团取代了七国集团成为国际社会应对金融危机最核心的机制,进而实现了国际金融治理机制的变迁。     

ENDOGENOUS TECHNOLOGICAL INNOVATION,CAPITAL ACCUMULATION AND DISTRIBUTIONAL DYNAMICS

This paper develops a post‐Keynesian dynamic model of accumulation, growth and distribution in which endogenous technological innovation plays a significant role. Firms’ rate of labour‐saving technological innovation is made to depend non‐linearly on the distributive (wage and profit) shares, with the latter determining both the incentives to innovate and the availability of funding to carry it out. As it turns out, the direction and the intensity of the effect of a change in distribution on the rates of accumulation and growth depend on the prevailing distribution, with a similar dependence applying—alongside the relative bargaining power of capitalists and workers—to the dynamic stability properties of the system. Hence, the model does not rely on full capacity utilization being reached for a change in the accumulation and growth regime to take place.     

A structural economic dynamics approach to balance-of-payments-constrained growth

This paper derives a balance-of-payments equilibrium growthrate analogous to Thirlwall's Law from a Pasinettian multi-sectormacrodynamic framework. The resulting formula, which we callthe Multi-Sectoral Thirlwall's Law, asserts that a country'sgrowth rate of per capita income is directly proportional tothe growth rate of its exports, with such a proportionalitybeing inversely (directly) related to sectoral income elasticitiesof demand for imports (exports). These income elasticities areweighted by coefficients that measure the share of each sectorin total imports and exports, respectively. It is shown thatseveral theoretical, empirical and policy implications can bedrawn from such a structural economic dynamics approach to balance-of-payments-constrainedgrowth.