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.     

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.     

松香皂引气剂的试验研究

文章介绍了一种通过正交试验合成的新的松香皂引气剂,并通过泡沫指标确定了其优化配比,同时分析了合成松香皂引气剂时的加热时间和搅拌时间对泡沫性能的影响。     

Optimal Contracts for Central Bankers: Inflation versus Money Supply and Exchange Rate Targets

Some recent papers have shown how a simple contract can eliminate the inflationary bias of discretionary monetary policy. This paper shows that if the central banker is risk averse, a contract in terms of money is superior to one in terms of inflation. The paper also shows that, if the central banker cares about his reappointment, an exchange rate target might always leads to the implementation of the optimal policy.     

Consistency of UK Pension Fund Investment Performance

Transition matrix techniques are used to relate the past and present performance of pension fund portfolios. In particular, funds are ranked to study the tendency of portfolios to remain in the same quartile of the ranking as they were in the previous period. For raw returns, funds in both of the top quartiles are found to be more likely to remain in the same quartile than would be expected by chance. This result can be taken as limited evidence for the consistency of performance. Similar systemic effects are observed on a risk-adjusted basis. There appears to be clear evidence that some fund managers can offer a degree of consistent good performance.