Mean squared error of the empirical best linear unbiased predictor in an orthogonal finite discrete spectrum linear regression model

The mean squared error (MSE) of the empirical best linear unbiased predictor in an orthogonal finite discrete spectrum linear regression model is derived and a comparison with the MSE of the best linear unbiased predictor in this model is made. It is shown that under weak conditions these two mean square errors are asymptotically the same.     

基于LINGO的带转运中心运输管理问题线性规划建模及求解

研究了多生产地、多销售地同时带多个中转站的运输转运问题,考虑了更符合实际的生产地和销售地也能作为中转站的情况,通过在中转站点中添加代表生产地和销售地的虚拟站点,得到求解该问题的虚拟转运网络图,进一步得到相应的线性规划模型,最后基于LINGO优化软件求解了一个运输转运问题实例,验证了模型的正确性。     

Quantiles as optimal point forecasts

Loss functions play a central role in the theory and practice of forecasting. If the loss function is quadratic, the mean of the predictive distribution is the unique optimal point predictor. If the loss is symmetric piecewise linear, any median is an optimal point forecast. Quantiles arise as optimal point forecasts under a general class of economically relevant loss functions, which nests the asymmetric piecewise linear loss, and which we refer to as generalized piecewise linear (GPL). The level of the quantile depends on a generic asymmetry parameter which reflects the possibly distinct costs of underprediction and overprediction. Conversely, a loss function for which quantiles are optimal point forecasts is necessarily GPL. We review characterizations of this type in the work of Thomson, Saerens and Komunjer, and relate to proper scoring rules, incentive-compatible compensation schemes and quantile regression. In the empirical part of the paper, the relevance of decision theoretic guidance in the transition from a predictive distribution to a point forecast is illustrated using the Bank of England’s density forecasts of United Kingdom inflation rates, and probabilistic predictions of wind energy resources in the Pacific Northwest.     

数学建模与创新应用型人才培养

培养具有创新精神的应用型人才已经成为很多大学的办学目标,数学建模正是培养学生创新精神与实践能力的有效方法。     

Agisoft photoscan在无人机航空摄影影像数据处理中的应用

根据航空摄影测量数据处理的实践与经验,对利用Agisoft photoscan软件进行无人机获取的影像数据进行处理,生成数字地表模型(DSM)和正射影像图(DOM)进行了探讨。     

An outlier test for linear processes — II. Large contamination

In Flak/Schmid (1993) an outlier test for linear processes was introduced. The test statistic bases on a comparison of each observation with a one-step predictor. It was assumed that an upper bound for the total number of outlierss _n is known, wheren denotes the sample size. The asymptotic distribution of the test statistic was derived under the assumption thats _n/n → 0 ands _n → ∞ asn → ∞. This note deals with the asymptotic behaviour of this quantity, ifs _n/n →p ₀ ∈ (0, 1).     

A Qualitative Study for Measuring Warehouse Performance Using Triangulation Approach

This research aims to validate a structural equation modeling （SEM） model for measuring warehouse performance using data from an international company in Australia （company G）. Moreover, a methodological triangulation method was also adopted to test whether different methodological approaches produce convergent findings about warehouse performance measurement （WPM）. These three different methods are the SEM model, the multiple case research study, and validation of the SEM model using data from 80 companies in Thailand and a company in Australia. With the results from the triangulation method, it is obvious that the SEM model can be used to measure the performance of warehouses in Thailand and Australia. Since the SEM model consists only of significant indicators, it is more appropriate than company G＇s scorecard. Furthermore, the SEM model can overcome the limitations of traditional models by allowing companies to compare their performance over time.     

The Measurement and Structural Modeling of the Reasonableness of Workplace Accommodations

The Americans with Disabilities Act of 1990 (ADA) guarantees protection from discrimination for persons with a disability. The ADA requires employers to make reasonable accommodations for persons with physical and mental disabilities unless doing so would produce undue hardship on the organization. Fifteen years after the passage of the ADA, the question as to what is a reasonable accommodation remains controversial, especially for some types of disabilities. In this study, a reasonable accommodation scale is proposed and tested using structural equation modeling in hopes that such a scale will aid the courts and organizations in determining what is reasonable. Individuals’ level of awareness of disability issues is also examined in the model to examine the relationship between awareness and willingness to accommodate. Results indicate acceptable fit of the model to the data and provide support for the proposed scale. Furthermore, the relationship between awareness of disability issues and willingness to accommodate was significant. Implications for research and practice are discussed.     

基于时间Petri网的生鲜肉冷链物流流程建模研究

以生鲜肉冷链物流为例,应用时间Petri网理论对冷链物流流程建模,研究冷链物流运作效率。用CPN tools对建立的模型运行后得到各环节的性能指标,发现流程中所存在的不足。最后提出对流程的改进建议。建模方法对复杂的冷链物流流程的建模和仿真有一定的参考价值,并为冷链物流以后的优化研究提供了新的思路。