基于神经网络的工程造价估价模型

利用神经网络方法更能充分有效地利用已有的经验,提高工程投资估算的速度和精度。经系统开发和案例计算,证明该方法能改进模糊类比法的估算结果,更好地满足工程项目初期造价估算的要求。     

浅谈企业成本管理的市场化

文本详细阐述了企业成本管理的市场化问题，对指导企业管理具有一定的借鉴价值。     

秦皇岛市海滨林场森林资产的评估

为促进海滨林场森林资产的增值和保值 ,以小班为单位 ,根据其树种和所处的龄组 ,分别选用几种方法进行了资产评估 ,经对评估结果的初步分析 ,幼、中、近成过熟林分别选用了重置成本法、林木期望价法和市场价格倒算法的评估结果。以整个林场为单位 ,利用 3种方法分别对林地价值进行了评估 ,最后选用了市价法的评估值作为评估结果     

黄丰桥林场毛竹林资产评估方法

毛竹林的资产评估在中国南方的森林资源资产评估中占有非常重要的地位,现有的毛竹林资产评估方法却难以对大面积的毛竹林资产进行有效地评估.提出了解决大面积毛竹林资产评估的可行方法,将毛竹林划分为新造竹林、立竹株数大于标准保留株数的竹林和立竹株数小于标准保留株数的竹林等3种类型分别进行评估;并对国营黄丰桥林场的423.1 hm2毛竹林进行了评估方法试验,证明该方法可行.     

浅谈施工项目成本管理

工程项目施工管理推行“项目经理责任制”和“项目成本核算制”是提高施工企业管理水平的有效管理模式。本文论述了“项目成本核算制”成本管理的理念特征和建立施工企业成本管理体系,掌握成本管理及控制的要点。     

国有农场场办企业改制成本的分析研究

国有农场的场办企业大多规模较小 ,在我国建立市场经济的过程中 ,场办企业的国有资产需要退出 ,企业需要改制 ,这需要国家付出一定的成本。如何使改制成本最小化是国家关心的重要问题。本文考虑场办企业改制中涉及的各方面因素 ,建立数学模型以期寻求企业改制中成本的最小值     

利用TCM法和CBA法对日本朝日林进行经济效益评价

从环境保护的角度出发,将旅行费用法TCM和费用效益法CBA结合起来,把TCM方法评价出的森林游憩效益纳入了森林的经济收益中,再用CBA法对日本朝日林进行了经济效益评价。评价结果,1997～2001年的游憩效益分别为1079、1084、1211、950、930万日元,B/C比值分别为1 39、1 48、1 29、1 15、1 19,平均值为1 3。这种考虑了森林的公益效益的经济效益评价方法,符合森林的可持续经营理论,比较合理地反映了森林的经济效益,为经营者的合理决策提供了参考。     

Potential impacts of carbon taxes on carbon flux in western Oregon private forests

This study considers a carbon tax system as a policy tool for encouraging carbon sequestration through modification of management in existing forests and examines its welfare impacts and costs of the carbon sequestered. The simulated carbon tax leads to reduced harvest and increased carbon stock in the standing trees and understory biomass. Changes in the level of silvicultural investments vary by owner, depending on the nature of their initial inventory. In general investment under the tax is concentrated in regimes that establish faster growing plantations. Average rotation age increases, varying in extent across ownerships and site qualities. The carbon tax reduces both consumer and producer surpluses in regional timber markets. Producers are compensated by the carbon subsidies, except at low carbon tax levels. Not all rates of carbon tax will attract interest from private owners if participation is voluntary. Estimates of the marginal cost of sequestering carbon in western Oregon private forests are shown to be within the range of costs for projects considering afforestation alone in some eastern regions of the United States.     

Grasshopper Plague Control in the Alpine Rangelands of the Qilian Mountains,China. A Socio‐Economic and Biological Approach

The probability and frequency of grasshopper plague outbreaks in the alpine rangelands of China have greatly increased since the middle of the last century, adversely affecting grassland ecosystems and the livelihood of herders. We propose that herders could use poultry to forage on grasshoppers to control plague. Here, we investigated the proximate (application in 2007) and persistence (continued effects across 2008–2011) effects of three different control agents (foraging chickens, a broad spectrum insecticide Beta‐Cypermethrin and an entomopathogenic fungus Metarhizium) on grasshopper population density. The comparative effectiveness of the three control agents was assessed by calculating grasshopper mortality and nymph:adult ratios. Subsequently, we examined the efficiency of chicken foraging activity at controlling grasshopper numbers under various levels of outbreaks. Finally, we used a cost–benefit analysis to assess the economic benefits of a traditional sheep rearing system versus a system that includes chicken rearing. In the first year, all three agents were initially effective at reducing grasshopper densities, but only chickens generated a persistence effect (lasting up to 5 years). Overall, chickens also provided the greatest economic benefits to herders than the other two control agents. Using foraging chickens to suppress grasshopper infestation in the alpine rangelands of China provides a novel approach toward mitigating outbreaks. Copyright © 2016 John Wiley & Sons, Ltd.