微波消解-原子荧光光谱法测定豆粉中总汞的不确定度评定

为了得到准确而完善的检测结果,对微波消解-原子荧光光谱法测定豆粉中总汞结果的不确定度进行了评定,结合各不确定度分量对测定方法中不确定度的主要来源进行了分析。结果表明:样品的前处理方法以及试样的重复性对获得准确测定结果尤为重要,标准曲线的配制也是重要的不确定度来源,同时需要确保仪器的稳定性,而试样定容和样品称样引入的不确定度极低,可以忽略。通过不确定度的评定,明确了测定过程中主要误差的来源,为降低检测过程中的误差提供了依据。     

Decision Support for Active Risk Management in Sustainable Forestry

Abstract

Active risk management is central to the implementation of sustainable forestry, yet a fairly unexplored field of research. This study attempts to present some components of an analytical framework for risk management centred on the decision situation. Within this framework, a systems analysis approach to providing decision support for risk management is presented with an example dealing with outcome risk. The approach covers identification of risk factors for which decision support could be useful for the problem holders, presentation of how one such risk factor, wind damage, can be characterised in terms of a computer model, and how this computer model can be used for providing decision support. In addition to outcome risk, there is risk due to knowledge uncertainty and uncertainty related to valuation. The implications of these uncertainties for active risk management are discussed. Furthermore, communicative criteria for making the decision support useful are discussed. Since the work on the concept is still under way, this is too early to evaluate. So far, however, our results have been met with interest not only from representatives of forestry but also from mass media.     

Analysis of the spawning stock–recruitment relationship of vendace (Coregonus albula (L.)) with evaluation of alternative models, additional variables, biases and errors

Abstract –  Spawning biomass and recruitment data for vendace from a central Finnish lake were analysed by fitting various recruitment models and comparing the fits statistically. The compensatory models of Ricker, Cushing and Beverton & Holt fitted the data better than the H ₀ hypothesis of constant proportionality, but model and parameter uncertainties were high. Additional variables were included in an attempt to reduce uncertainties. Heavy wind forcing during the first month after hatching of larvae reduced the recruitment success. For the Ricker and the Cushing models, recruitment seemed to be also negatively associated with the density of the previous year-class. The r ² increased considerably with inclusion of these additional variables, but the precision of model parameters remained low. Monte Carlo simulation of a vendace stock was applied to evaluate the interference of biases from the measurement error (ME) and time series error (TSE) in the analysis. Especially in the case of the Cushing model, compensatory density dependence can be overestimated severely. Increasing the number of observations decreases the biases in some cases. In view of potential biases and uncertainties, a precautionary management policy is recommended.     

对凯氏定氮法测定食品中蛋白质含量的测量不确定度评定

通过对凯氏定氮法测定食品中蛋白质含量的测量不确定度分析,对其标定结果的质量进行了定量表征。结果表明,该食品中蛋白质的含量为25.88%±0.15%(k=2),测量结果重复性的不确定度对总体不确定度作用最大。     

特种车辆柴油发动机故障诊断专家系统推理机设计

针对特种车辆柴油发动机故障诊断专家系统知识表示的模糊特性，建立了故障类型的模糊诊断模型，提出了不精确推理方法和模糊匹配策略，采用柴油发动机故障类型诊断的反向推理和故障原因分析及故障消除措施正向推理相结合的混合推理机制，设计了总体目标推理和级目标推理相结合的推理机．系统现场运行的快速推理结果表明了该推理机设计是成功的．     

Locating and protecting critical reserve sites to minimize expected and worst-case losses

There has been much recent interest in the development of systematic reserve selection methods that are capable of incorporating uncertainty associated with site destruction. This paper makes a contribution to this line of research by presenting two different optimization models for minimizing species losses within a planning region. Given limited acquisition budgets, the first minimizes expected species losses over all possible site loss patterns outside the reserve network while the second minimizes maximum species losses following the worst-case loss of a restricted subset of nonreserve sites. By incorporating the uncertainty of site destruction directly into the decision planning process, these models allow a conservation planner to take a less defensive and more strategic view of reserve selection that seeks to minimize species losses through the targeted acquisition of high-value/high-risk sites. We compare both of these methods to a more standard approach, which simply maximizes within reserve representation without regard for the varied level of threat faced by different sites and species. Results on a realistic dataset show that significant reductions in species losses can be achieved using either of these more intelligent modeling frameworks.     

凯氏定氮法测定大米中蛋白质的不确定度分析

采用GB/T5009.5-2003第一法,凯氏定氮法测定大米中蛋白质的含量,其测量不确定度来源于样品称量、消化、定容、移取消化液、蒸馏及滴定等过程。通过对各个不确定度分量的计算合成,找出影响测量不确定度的因素,并对各个不确定度分量进行评估,最终分析出样品大米中蛋白质的标准不确定度及扩展不确定度并描述了影响大米蛋白质测定结果各分量对其不确定度的相对贡献。     

利用广义不确定关系计算Vaidya-Bonner黑洞的熵

利用广义不确定关系计算量子态数目，进而计算Vaidya-Bonner黑洞的熵,此方法与brick-wall模型相比，优点为不必引入截断因子，就避免了发散问题。     

Incorporating parametric uncertainty into population viability analysis models

Uncertainty in parameter estimates from sampling variation or expert judgment can introduce substantial uncertainty into ecological predictions based on those estimates. However, in standard population viability analyses, one of the most widely used tools for managing plant, fish and wildlife populations, parametric uncertainty is often ignored in or discarded from model projections. We present a method for explicitly incorporating this source of uncertainty into population models to fully account for risk in management and decision contexts. Our method involves a two-step simulation process where parametric uncertainty is incorporated into the replication loop of the model and temporal variance is incorporated into the loop for time steps in the model. Using the piping plover, a federally threatened shorebird in the USA and Canada, as an example, we compare abundance projections and extinction probabilities from simulations that exclude and include parametric uncertainty. Although final abundance was very low for all sets of simulations, estimated extinction risk was much greater for the simulation that incorporated parametric uncertainty in the replication loop. Decisions about species conservation (e.g., listing, delisting, and jeopardy) might differ greatly depending on the treatment of parametric uncertainty in population models.