保险周期存在性的协整模型检验：基于中国市场的分析

本文对宏观经济波动可能引致保险周期的内在机理作了理论分析,然后利用协整模型并辅以误差修正模型验证了中国的现实情况,发现保险行业运行在长期来看与经济体系的发展较为一致,其周期特性得到间接证明,但经济的短期扰动对保险行业影响不大,同时,保险经营业绩与利率变动负相关,产险业的发展与宏观经济的联系不太紧密。     

(When) Should cointegrating regressions be detrended? The case of a German money demand function

If an economic relationship is superimposed by a linear time trend, the regression without detrending is misspecified. The estimators of such a regression do not converge to the true parameter values. First, the asymptotic limit arising from such misspecified regressions is characterized. Second, we observe with data before 1975 a significant time trend but no cointegrating relation between real money (M1), income and a long-term interest rate. The price level as a significant omitted variable is considered as an economic explanation for this feature. We find a price elasiticity larger than one. Third, with data after the breakdown of Bretton Woods (and the beginning of monetary targeting by the Bundesbank), real money, income and the interest rate alone are cointegrated. The long-run estimates seem to be fairly stable with data after the German union provided a step dummy accounts for a break in the mean. First version received: November 1996/final version received: June 1998     

Estimation and optimal designs for linear Haar-wavelet models

This paper gives an analytical expression for the best linear unbiased estimator (BLUE) of the unknown parameters in the linear Haar-wavelet model. From the analytical expression, we solve for the eigenvalues of the covariance matrix of the BLUE in analytical form. Further, we use these eigenvalues to construct some conventional discrete optimal designs for the model. The equivalences among these optimal designs are demonstrated and some examples are also given.      

Do different time horizons in the volatility of the US stock market significantly affect the China ETF market?

This article investigates the linear, nonlinear and time-varying Granger causality between different time horizons in the volatility of US stock market and the China Exchange-Traded Fund (ETF) market. We find evidence of linear causality from the US stock market to the China ETF market, with a bilateral nonlinear causal relationship in the longer term. Bootstrap rolling causality analysis indicates high rejection rates of a noncausal relationship running from the US stock market to the China EFT market. The causality linkage from the China ETF market to the US stock market was determined to be time-horizon-dependent, and the null hypothesis rejection rate of non-Granger causality increased in the longer term.     

Inter-metropolitan regional migration galvanized by high-speed rail: A simulation analysis of the Linear Chuo Shinkansen line in Japan

The development of transportation infrastructure impacts migration, production, and other economic activities along with it. In this study, we conducted a multiregional computable general equilibrium simulation analysis to assess the effects that the proposed 2027 high-speed railway, the Linear Chuo Shinkansen in Japan, will have on population migration. The 47 prefectures ordained by the Japanese administrative unit were considered, and the simulation potential workforce population was taken as 110 million. The population is concentrated in the Tokyo metropolitan area. As per our simulation, once the proposed high-speed railway opens, “travel costs” (comprising time and the monetary costs of traveling) will decrease. This situation will stimulate economic activities and lead people to migrate to the prefectures where the economic environment improves. The results show that this development will ease extreme population concentration while simultaneously increasing employment and production values. However, additional analysis indicates that further development of the Linear Shinkansen to strengthen the current high-speed rail on the route to Tokaido will increase population concentration.     

Optimizing the allocation of funds of an NFL team under the salary cap

Every NFL team faces the complex decision of having to choose how to allocate salaries to each position while being limited by the salary cap. This paper uses regression strategies to identify which positions are worthy of greater investment, under the assumption that players are paid in an efficient market. Using a combination of univariate regression models, we identify that it is worth investing in elite players at the quarterback, guard, defensive line, and linebacker positions. In addition, through a separate set of regression models we also consider the possibility that markets are not actually efficient. We determine that the optimal way to take advantage of inefficiency is through the draft, in order to find players who can provide significant win contributions early in their careers while they are being paid on relatively low rookie contracts.     

Thinning and harvesting in stochastic forest models

This paper analyzes a stochastic forest growth model in which the manager is able to first thin the forest to promote better growth before harvesting. Both Wicksell single thinning and harvesting cycle and Faustmann on-going rotation problems are considered. The Wicksell problem is analyzed by first restricting the class of decision times to (thinning, harvesting) pairs that bound the growth away from infinity and imbedding the problem in an infinite-dimensional linear program on a space of triplets of measures. These measures capture the thinning and harvesting decisions along with the behavior of the growth process prior to harvest. An auxiliary linear program then leads to a nonlinear optimization problem for which an optimal value and solution are determined. The values of all the problems are be related through a set of inequalities. The solution of the nonlinear problem determines (random) thinning and harvesting times for the single thinning and harvesting cycle which demonstrate the equality of the values of these various problems. Finally for the Wicksell problem, the unrestricted class of thinning and harvest times is shown to give the same value as the restricted class. The Faustmann on-going thinning and harvesting rotation problem is reduced to a Wicksell problem which then allows for the characterization of the value as the solution to a different nonlinear optimization problem. The effects of the opportunity to thin the forest are illustrated on a mean-reverting stochastic model.     

The Three Basic Types of Residuals for a Linear Model

We consider residuals for the linear model with a general covariance structure. In contrast to the situation where observations are independent there are several alternative definitions. We draw attention to three quite distinct types of residuals: the marginal residuals, the model‐specified residuals and the full‐conditional residuals. We adopt a very broad perspective including linear mixed models, time series and smoothers as well as models for spatial and multivariate data. We concentrate on defining these different residual types and discussing their interrelationships. The full‐conditional residuals are seen to play several important roles.     

Stock prices in Japan rise at night

Examining daily data of the Nikkei Average from 23 October 1986 to 20 January 1998, I find that although the mean of the rate of change during the trading hours (RT) is negative, the mean during non-trading hours (RNT) is significantly positive. I also find that (1) RT has a stable relationship with Japanese economic fundamentals while RNT does not, (2) RNT reflects US economic fundamentals, though weakly, and (3) if the previous trading hours reflected bearish trading, then the bearish sentiment is not taken over to opening time, as opposed to when the previous trading hours reflect a more bullish attitude. A possible cause of the positive RNT is optimism of Japanese investors, especially that of securities companies.     

EXTERNAL PIVOTING IN THE SIMPLEX ALGORITHM*

In this paper we describe the principle of external pivoting, a variant of the primal simplex algorithm. Its validity is proved in general and various strategies are designed which are based on this principle. The average convergence behavior for these strategies is then tested in a series of randomly generated problems. It is found that at least one of the strategies compares favorably with the regular simplex method.