工商管理学科建设:内涵、内部影响因素及其保障机制

现代大学通过系统扎实的学科建设,能够凝炼学科方向、发挥学科优势、突出学科重点、打造学科特色,因而这是值得肯定的正确战略。现代大学工商管理学科建设是高等教育中一项极其复杂的基础工程,具有十分丰富的内涵。在阐述现代大学工商管理学科建设内涵的基础上,分析了工商管理学科建设的内部影响因素,并进一步探讨了工商管理学科建设的保障机制。     

基于置信度判定的循环冗余校验纠错技术

以S模式下行数据链的检纠错为例,给出了基于置信度判定的循环冗余校验多位纠错技术,实现了突发和随机分布的多位差错的纠正,在不增加冗余码的情况下大大增强了循环冗余校验码的纠错能力.     

Advances in the Analysis of Non-stationary Time Series: An Illustration of Cointegration and Error Correction Methods in Research on Crime and Immigration

Time series data of interest to social scientists often have the property of random walks in which the statistical properties of the series including means and variances vary over time. Such non-stationary series are by definition unpredictable. Failure to meet the assumption of stationarity in the process of analyzing time series variables may result in spurious and unreliable statistical inferences. This paper outlines the problems of using non-stationary data in regression analysis and identifies innovative solutions developed recently in econometrics. Cointegration and error-correction models have recently received positive attention as remedies to the problems of ``spurious regression' arising from non-stationary series. In this paper, we illustrate the relevant statistical concepts concerning these methods by referring to similar concepts used in cross-sectional analysis. An historical example is used to demonstrate how such techniques are applied. It illustrates that ``foreign' immigrants to Canada (1896–1940) experienced elevated levels of social control in areas of high police discretion. ``Foreign' immigration was unrelated to trends in serious crimes but closely related to vagrancy and drunkenness. The merits of cointegration are compared to traditional approaches to the regression analysis of time series.     

Price dynamics in refined petroleum spot and futures markets

This article characterizes the spot and futures price dynamics of two important physical commodities, gasoline and heating oil. Using a non-linear error correction model with time-varying volatility, we demonstrate many new results. Specifically, the convergence of spot and futures prices is asymmetric, non-linear, and volatility inducing. Moreover, spreads between spot and futures prices explain virtually all spot return volatility innovations for these two commodities, and spot returns are more volatile when spot prices exceed futures prices than when the reverse is true. Furthermore, there are volatility spillovers from futures to spot markets (but not the reverse), futures volatility shocks are more persistent than spot volatility shocks, and the convergence of spot and futures prices is asymmetric and non-linear. These results have important implications. In particular, since the theory of storage implies that spreasd vary with fundamental supply and demand factors, the strong relation between spreads and volatility suggests that these fundamentals — rather than trading induced noise — are the primary determinants of spot price volatility. The volatility spillovers, differences in volatility persistence, and lead-lag relations are consistent with the view that the futures market is the primary locus of informed trading in refined petroleum product markets. Finally, our finding that error correction processes may be non-linear, asymmetric, and volatility inducing suggests that traditional approaches to the study of time series dynamics of variables that follow a common stochastic trend that ignore these complexities may be mis-specified.     

On optimal allocations for estimating the surface of a random field

In general, the construction of optimal designs is apparently a difficult task for the approximation of a random field indexed by more than one dimension. Besides the rate of convergence of the minimum achievable error hardly anything is known until now. However, if there is an immanent structure present in the random field, then, taking this structure into account, improved estimates can be obtained. For this situation we present adequate designs which show, at least, a nearly optimal performance. work supported by 313/ARC/VII/93/151 of the DAAD work supported by Ku719/2-1 of the DFG     

Identifying, estimating and testing restricted cointegrated systems: An overview

The notion of cointegration has led to a renewed interest in the identification and estimation of structural relations among economic time series. This paper reviews the different approaches that have been put forward in the literature for identifying cointegrating relationships and imposing (possibly over-identifying) restrictions on them. Next, various algorithms to obtain (approximate) maximum likelihood estimates and likelihood ratio statistics are reviewed, with an emphasis on so-called switching algorithms. The implementation of these algorithms is discussed and illustrated using an empirical example.     

A note on the expectations hypothesis at the founding of the Fed

One of the most influential tests of the expectations hypothesis is Mankiw and Miron [Q. J. Econ. 101 (1986) 211], who found that the spread between the long-term and short-term rates provided predictive power for the short-term rate before the Fed's founding but not after. They suggested that the failure of the expectations hypothesis after the Fed's founding was due to the Fed's practice of smoothing short-term interest rates. We show that their finding that the expectations hypothesis fares better prior to the Fed's founding is due to the fact that the test they employ tends to generate results that are more favorable to the expectations hypothesis during periods when there is extreme volatility in the short-term rate.     

Market Segmentation and Information Asymmetry in Chinese Stock Markets: A VAR Analysis

This study examines the market segmentation and information asymmetry patterns in Chinese stock markets. The recursive cointegration analysis confirms that each of six markets is not linked with other markets in the long run. Further, the result from data‐determined forecast error variance decomposition clearly shows that foreign investors in the Shanghai B‐share market are better informed than Chinese domestic investors in two A‐share markets and foreign investors in Shenzhen and Hong Kong markets over time. The finding challenges a widespread assumption of less informed foreign investors in the literature, but suggests that foreign investors could be more informed in emerging markets.     

On second-price auctions and imperfect competition

Consider two sellers each of whom has one unit of an indivisible good and two buyers each of whom is interested in buying one unit. The sellers simultaneously set reserve prices and use second-price auctions as rationing device. An equilibrium in pure strategies where each seller has a regular customer is characterized. The result is applied in order to demonstrate that not allowing sellers to use second-price auctions may enhance total surplus.     

单片机在嵌入式系统应用中的抗干扰措施

单片机在嵌入式系统应用中，抗干扰性能是系统可靠性的重要指标，抗干扰设计是单片机系统研制中不可忽视的一个重要内容。本文根据笔者在实际工作中的体会，就单片机在嵌入式系统应用中的抗干扰问题进行探讨，并给出了排错设计、容错设计的一些方法和措施。