The approximation capabilities of the minflex-Laurents,translog, and generalized Leontief forms

This paper compares the approximation capabilities of the minflex-Laurents translog and minflex generalized Leontief cost functions with their translog and generalized Leontief counterparts in Monte Carlo experiments. The minflex Laurent specifications generally provided closer approximations to underlying technical and economic parameters. Imposition of nonlinear restrictions on some of the parameters of the minflex Laurent models yielded measurable improvement in estimated elasticities of substitutions, returns to scale, and rates of technical change.The refereeing process of this paper was handled through E. Appelbaum.     

考虑供给与需求波动性的安全库存定量研究

本文以商业企业和MTS模式下生产企业的安全库存为研究对象,将供给与需求的变动程度作为两个动态指标研究四种不同战略与运营环境下的安全库存模型,并进一步分析了降低安全库存所需的管理杠杆.     

Incentives and Performance in Real Estate Brokerage

This article has two objectives. One is to offer a theoretical model to study how the difference in commission structures affects the performance of agents at full-commission firms (e.g., RE/MAX agents) relative to other agents. The other is to provide an empirical test of the relative performance of full-commission agents. We predict that in equilibrium the selling price and the expected time it takes to sell a listing through a full-commission agent are the same as they are with a traditional agent. Our theoretical predictions are supported by our empirical results.     

A note on the existence of unique equivalent martingale measures in a Markovian setting

Simple sufficient conditions for the existence of a unique equivalent martingale measure are provided. Furthermore, these conditions give us a handle on situations where an equivalent martingale measure cannot exist. The existence of a unique equivalent martingale measure is of relevance to problems in mathematical finance. Two examples of models for which the question of existence was unresolved are studied. By means of our results existence of a unique equivalent measure up to an explosion time is proved.     

试论生态林业系统的时空观

生态林业系统具有时间、空间两个序列的开发前景。长周期,大跨度的生态林业生产可以分解为复合的短周期方式,使生态意识与经济效益有机结合。空间组合的多层次立体开发有效地利用了光、热、水、土资源,并获得最大生物量;地域组合着眼宏观,注重研究大型骨干及网络性生态工程问题。     

Working-time reduction and employment: experiences in Europe and economic policy recommendations

The paper seeks to evaluate the evidence on the employment effectsof the collective working-time reductions in Europe over thepast 20 years. While theoretical analyses produce contradictoryassessments, most empirical studies show positive employmenteffects but take insufficient account of these conditions underwhich the reductions in working time were implemented. Theseconditions for the success of collective working-time reductionsinclude an active training policy designed to minimise skillshortages in the labour market, the modernisation of work organisation,wage increases in conjunction with productivity gains and amore equal income distribution.     

Does price reflect emotional,structural or performance quality?

Three denim jeans products from the same manufacturer with differentiated pricing and labels (antiqued, sandblasted, and stonewashed) were used to determine the relationship between price and quality. Both qualitative and quantitative procedures were used to analyse the garments. All three jeans were made of twill weave with 3 × 1 repeat. Both structural and performance characteristics were compared using standardized tests. Analysis of variance was used to compare the selected structural and performance characteristics among the three jeans products. Tukey’s HSD tests were used for post hoc multiple comparisons for three jeans. The findings revealed that despite the fact that all three jeans products were from the same store, and that the fabrics used the same weave, degree and direction of twist, the jeans differed significantly for several structural and performance characteristics. Several possibilities for future research were explored.     

Forecasting residential burglary

Following the work of Dhiri et al. [Modelling and predicting property crime trends. Home Office Research Study 198 (1999). London: HMSO] at the Home Office predicting recorded burglary and theft for England and Wales to the year 2001, econometric and time series models were constructed for predicting recorded residential burglary to the same date. A comparison between the Home Office econometric predictions and the less alarming econometric predictions made in this paper identified the differences as stemming from the particular set of variables used in the models. However, the Home Office and one of our econometric models adopted an error correction form which appeared to be the main reason why these models predicted increases in burglary. To identify the role of error correction in these models, time series models were built for the purpose of comparison, all of which predicted substantially lower numbers of residential burglaries. The years 1998–2001 appeared to offer an opportunity to test the utility of error correction models in the analysis of criminal behaviour. Subsequent to the forecasting exercise carried out in 1999, recorded outcomes have materialised, which point to the superiority of time series models compared to error correction models for the short-run forecasting of property crime. This result calls into question the concept of a long-run equilibrium relationship for crime.     

The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

Multiple generation product life cycle predictions using a novel two-stage fuzzy piecewise regression analysis method

Product life cycle (PLC) prediction plays a crucial role in strategic planning and policy definition for high-technology products. Forecast methodologies which can predict PLCs accurately can help to achieve successful strategic decision-making, forecasting, and foresight activities in high-technology firms, research institutes, governments, and universities. Over the past few decades, even though analytic framework strategies have been proposed for production, marketing, R&D (research and development), and finance, aiming at each stage of PLCs, forecast methodologies with which to predict PLCs are few. The purpose of this research is to develop a novel forecast methodology to allow for predictions of product life time (PLT) and the annual shipment of products during the entire PLC of multiple generation products. A novel two-stage fuzzy piecewise regression analysis method is proposed in this paper. In the first stage, the product life-time of the specific generation to be analyzed will be predicted by the fuzzy piecewise regression line that is derived based upon the product life-time of earlier generations. In the second stage of the forecast methodology, the annual shipment of products of the specified generation will be predicted by deriving annual fuzzy regression lines for each generation, based upon the historical data on the earlier generations' products. An empirical study predicting the life-time and the annual shipment of the 16 Mb (Mega bit) DRAM (Dynamic Random Access Memory) PLC is illustrated to validate the analytical process. The results demonstrate that two-stage fuzzy piecewise regression analysis can predict multiple generation PLT and PLC precisely, thereby serving as a foundation for future strategic planning, policy definitions and foresights.