Different forest fires causing different degrees of effects occur in fire-sensitive forests due to various reasons such as climate change.Useful as well as harmful aspects of forest fires are a multi-disciplinary rese...Different forest fires causing different degrees of effects occur in fire-sensitive forests due to various reasons such as climate change.Useful as well as harmful aspects of forest fires are a multi-disciplinary research topic.Geographical information systems(GIS)and remote sensing(RS)methods offer a number of benefits for researchers and operators in the field of forest fire research.The present study analyses timber pricing based on forest contractor demands of post-salvage logging processes.The effect of timber obtained from compartment units on producers’pricing policy was modelled.Sapadere forest fire area(2500 ha)located in Antalya in Turkey was selected as the main study area.Topography parameters(aspect,slope and slope position),stand types(diameter class and crown closure),and burn severity were analyzed together using GIS and R software packages.A multi-linear regression model(R^(2)=0.752)demonstrated that factors that had the most impact on pricing were slope position,aspect,stand age,crown closure and burn severity.This model can be used to estimate salvage logging prices in Calabrian pine(Pinus brutia Ten.)stands with similar parameters.Forest administrators and contractors may readily address the unit price of timber by estimating approximate costs in a given forest area for which they are going to bid.This will help reduce operational planning times of harvesting procedures in burned stands.展开更多
为设计低成本、高效能的卫星,提出了一种卫星全寿命周期效费权衡优化方法,结合卫星不可修、在轨运行中可能存在降级使用等情况,建立了以ADC(availability,dependability,capacity)模型为基础的全寿命周期效能评估模型,提出了多维度参数...为设计低成本、高效能的卫星,提出了一种卫星全寿命周期效费权衡优化方法,结合卫星不可修、在轨运行中可能存在降级使用等情况,建立了以ADC(availability,dependability,capacity)模型为基础的全寿命周期效能评估模型,提出了多维度参数成本模型以评估卫星费用,开发了基于CAIV(cost as an independent variable)方法的效费优化模型及求解方法。以遥感卫星为例开展应用验证,结果表明,所提出的方法可实现能力指标、可靠性和重量等卫星总体设计指标优化,为卫星方案论证、任务管理、全寿命周期费用管控等工作提供指导。展开更多
In parametric cost estimating, objections to using statistical Cost Estimating Relationships （CERs） and parametric models include problems of low statistical significance due to limited data points, biases in the un...In parametric cost estimating, objections to using statistical Cost Estimating Relationships （CERs） and parametric models include problems of low statistical significance due to limited data points, biases in the underlying data, and lack of robustness. Soft Computing （SC） technologies are used for building intelligent cost models. The SC models are systemically evaluated based on their training and prediction of the historical cost data of airborne avionics systems. Results indicating the strengths and weakness of each model are presented. In general, the intelligent cost models have higher prediction precision, better data adaptability, and stronger self-learning capability than the regression CERs.展开更多
文摘Different forest fires causing different degrees of effects occur in fire-sensitive forests due to various reasons such as climate change.Useful as well as harmful aspects of forest fires are a multi-disciplinary research topic.Geographical information systems(GIS)and remote sensing(RS)methods offer a number of benefits for researchers and operators in the field of forest fire research.The present study analyses timber pricing based on forest contractor demands of post-salvage logging processes.The effect of timber obtained from compartment units on producers’pricing policy was modelled.Sapadere forest fire area(2500 ha)located in Antalya in Turkey was selected as the main study area.Topography parameters(aspect,slope and slope position),stand types(diameter class and crown closure),and burn severity were analyzed together using GIS and R software packages.A multi-linear regression model(R^(2)=0.752)demonstrated that factors that had the most impact on pricing were slope position,aspect,stand age,crown closure and burn severity.This model can be used to estimate salvage logging prices in Calabrian pine(Pinus brutia Ten.)stands with similar parameters.Forest administrators and contractors may readily address the unit price of timber by estimating approximate costs in a given forest area for which they are going to bid.This will help reduce operational planning times of harvesting procedures in burned stands.
文摘为设计低成本、高效能的卫星,提出了一种卫星全寿命周期效费权衡优化方法,结合卫星不可修、在轨运行中可能存在降级使用等情况,建立了以ADC(availability,dependability,capacity)模型为基础的全寿命周期效能评估模型,提出了多维度参数成本模型以评估卫星费用,开发了基于CAIV(cost as an independent variable)方法的效费优化模型及求解方法。以遥感卫星为例开展应用验证,结果表明,所提出的方法可实现能力指标、可靠性和重量等卫星总体设计指标优化,为卫星方案论证、任务管理、全寿命周期费用管控等工作提供指导。
文摘In parametric cost estimating, objections to using statistical Cost Estimating Relationships （CERs） and parametric models include problems of low statistical significance due to limited data points, biases in the underlying data, and lack of robustness. Soft Computing （SC） technologies are used for building intelligent cost models. The SC models are systemically evaluated based on their training and prediction of the historical cost data of airborne avionics systems. Results indicating the strengths and weakness of each model are presented. In general, the intelligent cost models have higher prediction precision, better data adaptability, and stronger self-learning capability than the regression CERs.
