连续时间系统的精确模型匹配控制

本文着重论述了连续时间系统的时域精确模型匹配控制和频域精确模型匹配控制问题。本文介绍的第二类精确模型匹配控制系统的设计方法是复杂控制系统设计的基础(如解耦控制及自适应控制等)。     

集成运放的一些使用技巧

目前集成技术飞速发展且集成芯片已被广泛应用 ,为了充分利用集成在一个芯片上的两个运算放大器性能互相匹配的特点 ,本文从三个方面介绍了合理使用集成运算放大器的几种技巧。其中 ,利用集成在一个硅片上的两个运算放大器的输入失调电压极其温度漂移相互补偿的原理 ,组成了失调电压极低的运算放大器 ;根据输入电阻的自举扩展原理 ,利用集成在一个硅片上的两个运算放大器组成的反向比例运算放大器具有很高的输入电阻和较高的电压放大倍数 ;根据差动放大电路的输出电压方式 ,利用集成在一个硅片上的两个运算放大器组成的差动输出运算放大器 ,最大线性输出电压范围比一个集成运算放大器的最大线形输出电压范围大一倍。且适用于不接地负载。     

Position auctions

I analyze the equilibria of a game based on the ad auction used by Google and Yahoo. This auction is closely related to the assignment game studied by Shapley–Shubik, Demange–Gale–Sotomayer and Roth–Sotomayer. However, due to the special structure of preferences, the equilibria of the ad auction can be calculated explicitly and some known results can be sharpened. I provide some empirical evidence that the Nash equilibria of the position auction describe the basic properties of the prices observed in Google's ad auction reasonably accurately.     

Can an Unemployment Insurance System Generate Multiple Natural Rates?

This article studies some macroeconomic consequences of the financing of an unemployment insurance scheme. Under a balanced-budget rule, when both taxes and unemployment benefits are proportional to wages, the existence of multiple natural rates of unemployment is a generic property of the matching model. Government can lead the economy to a high equilibrium by fixing the rate of tax on wages and then setting the replacement ratio so that its expenditure matches its receipts.     

大功率电子发射管的正确使用及延长其寿命的方法

大功率电子发射管广泛应用于广播电视发射设备及其他电子通信设备,文章介绍了采用冷打压老炼、灯丝电压调整、谐振匹配等技术方法延长电子管的使用寿命。     

From quality to innovation: Evidence from two French Employer Surveys

In this article we investigate the impact of quality systems on innovation performance using the method of propensity matching. We use two French microeconomic surveys, the “Organizational Changes and Computerization” (COI 1997) and the “Community Innovation Survey” (CIS3 1998–2000). The first hypothesis indicating that quality (ISO 9000 certification) impacts positively on innovation is supported for certain areas of innovation performance. Furthermore, the second hypothesis states that different levels of quality differentially improve innovation performance. Results indicate that the innovation performance of firms with Top Quality Level is higher than that of firms with Medium Quality Level which is also higher than that of firms with Low Quality Level for certain areas of innovation. However, we found that the difference in innovation performance between firms with Medium and Low Quality Levels is not of a great magnitude. This study implies that in order to achieve a significant innovation performance improvement via quality systems, a very well-established quality system is needed within a firm.     

Corrigendum to “On randomized matching mechanisms” [Economic Theory 8(1996)377–381]

Ma (in Econ. Theory 8, 377–381, 1996) studied the random order mechanism, a matching mechanism suggested by Roth and Vande Vate (Econometrica 58, 1475–1480, 1990) for marriage markets. By means of an example he showed that the random order mechanism does not always reach all stable matchings. Although Ma's (1996) result is true, we show that the probability distribution he presented – and therefore the proof of his Claim 2 – is not correct. The mistake in the calculations by Ma (1996) is due to the fact that even though the example looks very symmetric, some of the calculations are not as “symmetric.” We thank two anonymous referees for their helpful comments. B. Klaus’s and F. Klijn’s research was supported by Ramón y Cajal contracts of the Spanish Ministerio de Ciencia y Tecnología. The work of the authors was also partially supported through the Spanish Plan Nacional I+D+I (BEC2002-02130 and SEJ2005-01690) and the Generalitat de Catalunya (SGR2005-00626 and the Barcelona Economics Program of CREA).     

Is there really a foreign ownership wage premium? Evidence from matched employer-employee data

Numerous studies on firm-level data have reported higher average wages in foreign-owned firms than in domestically owned firms. This, however, does not necessarily imply that the individual worker's wage increase with foreign ownership. Using detailed matched employer-employee data on the entire Swedish private sector, we examine the effect of foreign ownership on individual wages, controlling for individual and firm heterogeneity as well as for possible selection bias in foreign acquisitions. We distinguish between foreign greenfields and takeovers and compare foreign-owned firms with both domestic multinationals and local firms. Our results show a considerably smaller wage premium in foreign-owned firms than what has been found in studies conducted at a more aggregate level. Moreover, foreign takeovers of Swedish firms tend to have no or even a negative effect on wages.     

股权激励存在持续性的激励效应吗？--基于倾向得分匹配法的实证分析

为克服样本选择偏误,本文采用倾向得分匹配法,在六年的时间框架内检验了股权激励效应的持续性问题。研究发现：整体而言,激励组的ROE和Tobin’s Q值均显著高于控制组,说明股权激励能有效地提高企业的财务绩效和市场价值;激励组的ROE在股权激励计划实施后的三年时间里均显著高于控制组,三年之后逐渐与控制组无显著差异,表明股权激励对企业财务绩效的提升作用能持续三年时间;激励组的Tobin’s Q值在实施的第一年与控制组无显著差异,但在随后的四年时间里均显著高于控制组,表明股权激励对企业市场价值存在长达四年的持续提升作用,但存在为期一年的时滞效应。     

分块自适应图像稀疏分解

针对图像稀疏分解的计算时间复杂度非常高这个问题，提出了分块自适应图像稀疏分解算法。该算法根据稀疏分解计算时间复杂度和待分解图像大小之间的关系。把待分解图像分成互不重叠的小块。然后对每个小块图像进行稀疏分解。根据每一块的复杂程度。自适应地决定稀疏分解的结束。实验结果表明。在分解原子个数相近或相同的条件下。新算法对稀疏分解后重建图像比在整幅图像上进行稀疏分解重建的图像质量下降0．5dB。但计算速度提高了约15倍。