基于效应的随机灰规划模型和应用

为了解决同时含有随机因素和灰色因素的不确定规划问题,通过结合区间灰数所属区间两个端点的随机性,给出随机区间灰数和随机区间灰函数的定义,提出了随机灰规划模型。通过综合效应函数理论用随机变量期望值和方差综合量化表示灰数所属区间的两个端点值。应用该理论对综合量化后的两个端点值继续进行综合量化,从而将随机灰规划转化为确定型规划问题。应用遗传算法进行求解。通过综合效应函数的理念,综合随机变量的期望和方差,同时综合区间灰数的区间因素,将随机灰规划数学模型转化为确定型规划模型即基于效应的随机灰规划模型。通过选取不同的综合效应函数,得到了关于不同决策意识下的随机灰规划的最优解。这个方法可为决策者进行不确定决策提供参考。     

专用性人力资本投资与饭店业基层员工低薪酬现象成因解释

我国饭店业正逐步演变为典型的低薪酬行业,主要表现为固定工资合约逐渐成为主导性薪酬契约,且固定工资基数水平不断下降。文章运用专用性人力资本理论,解释了在隐性知识管理机制缺失的条件下,饭店业主为什么会放弃对专用性人力资本投资收益的追求而选择固定工资合约,并进一步分析了固定工资合约的实际支付水平为什么会逐步下降,直至最终形成接近法定最低工资标准的全行业统一价格。     

内聚与开放:花生对英租时期威海乡村社会的影响

在英租威海卫时期,花生的推广使得威海乡村社会的封闭状态产生了变化.在花生的种植、管理、收获及销售过程中,销售这个环节加强了村庄对外界的依赖,体现出开放性,种植到收获各个环节中的生产联合则基本上局限于村庄内部,仍保持传统的内聚性.这种传统与现代的结合,体现出当时威海乡村社会的一种变化趋势.     

山东省农业可持续发展能力评价研究--基于非整秩次WRSR

根据包含3个一级指标、6个二级指标和30个三级指标的评价体系,使用均方差赋权法和非整秩次WRSR,对山东省17个地市的农业可持续发展能力进行评价和分档分析,结果表明：青岛、德州和潍坊处于强势区,日照和莱芜处于弱势区,而其他地市处于中档区;各市农业可持续发展能力与其一二级指标之间都存在显著相关关系。因此,处于强势区的三地市应从二三级指标入手重点提升相对较弱的指标,保持竞争优势;处于弱势区的两地市以及处于中档区末位的东营和枣庄两地市,应通过优化资源配置和发展多功能农业来探寻农业可持续发展能力提升的突破口;处于中档区的其他十地市应充分利用其个别优势指标寻求农业可持续发展能力的突破,并重点提升部分劣势指标。     

Assessing cost‐effectiveness when environmental benefits are bundled: agricultural water management in Great Barrier Reef catchments

Using economic analysis to prioritise improvements in environmental conditions is particularly difficult when multiple benefits are involved. This includes ‘bundling’ issues in agricultural pollution management, where a change in management action or farming systems generates multiple improvements, such as reductions in more than one pollutant. In this study, we conceptualise and compare two different approaches to analysing cost‐effectiveness when varying bundles of benefits are generated for a single project investment. Each approach requires data to be transformed in some way to allow the analysis to proceed. The index approach requires the transformation on the benefits side so that the effects of multiple pollutant changes can be combined into a measure for each project which can then be compared to costs. By comparison, the disaggregation approach requires the transformation on the costs side where costs for each project have to be apportioned across the different pollutants involved. The paper provides novel insights with an application to agricultural water quality improvements into the Great Barrier Reef in Australia, demonstrating that while both approaches are effective in prioritising projects by cost‐effectiveness, the disaggregation approach provides more insightful results and values that may be relevant for use as upper value guidelines in future project selection.     

分形图及图案设计

本文讨论了各种分形图及在图案设计中的应用 ,并提出了利用这些分形图生成图案的一些方法。     

北部湾城市群基础设施与经济协调发展研究

本文从基础设施的不同功能出发,以经济性、生活性、社会性来划分北部湾地区城市群的基础设施指标,运用VAR模型实证分析了1990～2009年北部湾城市群基础设施与经济发展之间的关系。结果表明,经济增长与基础设施之间有正向协整关系,其中社会性和经济性基础设施对经济增长显示正向协整关系,生活性基础设施与经济增长是负向协整关系。     

EXTREME VALUE AT RISK: A SCENARIO FOR RISK MANAGEMENT

This paper uses the generalised extreme value (GEV) distribution to model the extreme losses that are likely to occur during market crashes, in the case of an investor who has long positions in stocks and currencies. The null hypothesis – which tests for normality of asset returns – is rejected due to asymmetry of these returns. We assume that the asymmetric behaviour and volatility of the returns are captured by the shape and scale parameters, respectively, of a GEV distribution. The data set includes stock indices for the United States, Japan, the United Kingdom, Germany, France and South Africa, and the South African rand exchange rates against the US dollar observed from 3 January 2005 to 30 December 2009. In addition, we divide this sample period into two periods: the pre‐crisis period, from 3 January 2005 to 31 December 2007 and the crisis period, from 1 January 2008 to 30 December 2009. We compared the estimates of value at risk (VaR) using an extreme value theory (EVT) model, with the estimates derived from the traditional variance–covariance method and found that during the crisis the 99% extreme VaR estimates are more reliable as they lie within the Basel II green zone. These results suggest that, at higher quintiles, the VaR estimates based on EVT are reliable and more accurate than estimates from the traditional method.     

随机正交变换法在隐私保持关联规则挖掘中的应用

隐私保护是当前数据挖掘领域中一个十分重要的研究方向。本文针对关联规则挖掘中如何保持隐私的问题,采用一种不依赖具体数据的随机正交变换方法,从而解决了在数据集容量很大的情况下,运算量大的问题,并使用传统隐私保护度评价方法与正交变换的方向隐私保护度相结合的方法评价变换的隐私保护度,进而使得结果更符合实际情况。理论分析和论证表明本文中的方法具有很好的隐私性、高效性和适用性。     

国内外科技旅游的发展及研究综述

随着全球旅游业的迅猛发展、科学技术的不断进步、“科技”与“旅游”的逐步结合,科技旅游蓬勃兴起,已成为现代旅游业的重要组成部分,并在旅游实践中发挥着越来越重要的作用。文章针对国内外科技旅游发展情况及研究状况进行了综述,并结合国内外科技旅游发展及其研究的对比分析,对我国科技旅游的开发研究进行了展望。