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本文讨论了运用整体综合方法评价不确定性对油气投资决策影响的必要性。我们认为,仅对于投资决策评价各种要素的综合性常规精确模型增添处理不确定性的功能,是不能有效达到上述目的的。此外我们还认为,这种方法即使是可行的,也并不是人们所期望的。因此我们提出了在决策支持系统中引入整体和概率评价方法的概念。这种整体分析方法有两种要素。一种是技术要素,它综合了各种评价和决策工具。另一种是模拟思路要素,它全面考虑了不确定性的广度和规模。为了更全面、准确和严格地评价不确定性对投资决策过程的影响,这种方法要牺牲一部分技术精度和细节。这种系统的基本组成主要有各领域的简化要素模型、蒙特卡罗模拟工具以及模拟语言,可用于满足用户的特殊要求、综合不同要素之间的相互依赖关系、执行决策逻辑以及作为学习结果更新信息。文中说明了这种系统如何识别哪种不确定性对决策影响最大、如何评价信息采集(数据、技术分析)的价值以及如何在缓解和/或利用不确定性的下一步计划中促进灵活性。其他应用还有优化开发情景、评价真实的选择情景以及为投资组合分析的输入数据生成统一的风险现金流。这种系统的应用已通过其综合技术决策和经营决策的能力,使多学科资产管理团队的工作实现了真正的以价值驱动为重点。  相似文献   
3.
Bacteriophages as accessory genetic elements play a crucial role in the dissemination of genes and the promotion of genetic diversity within bacterial populations. Such horizontal transfer of DNA is critical in the emergence of new pathogenic organisms, through the dissemination of genes encoding virulence factors such as toxins, adhesins and agressins. Phages can transfer genes that are not necessary for bacteriophage persistence and are generally recognised by their ability to convert their host bacteria to new phenotypes. This phenomenon is known as phage conversion. If such converting genes encode for virulence factors, the consequences of phage infection may include increased virulence of the host bacteria, and the conversion of a non‐pathogenic strain to a potentially dangerous pathogen. A number of virulence factors in bacteria causing diseases in plants, animals and humans are encoded by converting phages, the vast majority of which are temperate as opposed to lytic in nature. © 2001 Society of Chemical Industry  相似文献   
4.
Words that are generated as responses to incomplete stimuli are remembered better than complete words that are read. The present research shows that the generation effect occurs only if both reading and generating are done in the same list. Comparisons with unmixed reading controls reveal that the effect occurs because the read words are remembered poorly; the generated ones are no better than the controls. Therefore, the question for theories is not why generating helps memory, but why the demand to generate makes people lazy readers. Furthermore, cued recall of pairs of unrelated words is worse if they were generated than if they were read. We propose that generation is a demand to identify words as independent events. There is nothing special about generating, but the demand to generate is special; it hurts reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
The generation effect occurs if people remember items they complete from fragments better than complete items they read. Four experiments investigate two questions. When does the effect occur, and why does it do so? Targets generated in related contexts are recognized better than read targets, and they are recalled better with the contexts as cues; the contexts are recognized equally well, and the relation between the context and target is not enhanced by generation. Furthermore, generated items exceed items read in pure lists even when read ones from the mixed list are no worse than the controls. The generation effect is real; it is not an artifact. However, there is nothing special about generation. Generating is a type of encoding, and like any other type of encoding, its effects are maximal on tests that require subjects to do again whatever they did at study. Generating makes targets distinctive by contrasting them with other relatives of the context, and, as a result, the targets enjoy benefits in later discriminations within their family. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
The interactions between stainless steel (SS) and a glass-ceramic designed for immobilisation of the high-level nuclear waste generated at the Idaho chemical processing plant (ICPP) under hot isostatic pressing (HIPing) conditions (100 MPa in argon at 1200 °C) have been studied and subsequently the effect of such interactions on the chemical durability of the glass-ceramic waste form has been examined. The diffusion of Cr from SS (Cr depletion in SS) through the interaction layer and formation of crystalline Cr/Al oxides in glass dominate the overall interaction process. It appears that the depletion of Cr in SS may reduce the potential of SS as a barrier. However, such interactions have no significant impact on the glass-ceramic and the presence of the interaction layer does not seem to have any detrimental effect on the chemical durability of the glass-ceramic as a waste form.  相似文献   
7.

Aim

To examine the influence of parental knowledge of, and support for graduated driver licensing (GDL) conditions, parental management of adolescent driving and parental driving behaviour on adolescent compliance with GDL conditions and crashes as a restricted licence driver.

Method

This research was part of the New Zealand Drivers Study (NZDS), a prospective cohort study of 3992 newly licensed car drivers. NZDS participants were recruited at the learner licence stage, with follow-up aligned with the GDL stages. At the restricted licence stage 1200 parents of NZDS adolescents, aged 15–17 years at learner licensure, were recruited and completed interviews. 895 of these adolescents progressed to their full licence and completed the full licence interview. These 895 parent–adolescent pairs were the study population in this research. Topics examined included parental knowledge of, and support for GDL conditions, management of adolescent driving (driving rules, adolescent vehicle ownership, delaying licensure), and their own driving behaviours. Outcomes examined were adolescent compliance with GDL restricted licence conditions (night-time and passenger), and crashes as a driver during the restricted licence stage.

Results

After controlling for other variables, factors independently associated with adolescent low compliance with GDL conditions were: low parental knowledge of conditions, parents’ implementing few driving rules, adolescent vehicle ownership, and parent crash involvement. Factors independently associated with adolescents being a crash involved driver were: parents’ actively delaying licensure, adolescent vehicle ownership, and parent crash involvement.

Conclusion

There is increasing recognition of the importance of parental involvement in adolescent driving. The results show that parents are influential in determining adolescent compliance with GDL and risk of crash. Parents can have considerable positive influence on their adolescent's driving through ensuring compliance with the components of GDL, limiting vehicle ownership and by modelling safe driving behaviours.  相似文献   
8.

Objective

The aim of this study was to determine whether pre-licence driving experiences, that is driving before beginning the licensing process, increased or decreased crash risk as a car driver, during the learner or the restricted licence stages of the graduated driver licensing system (GDLS).

Method

Study participants were 15–24 year old members of the New Zealand Drivers Study (NZDS) – a prospective cohort study of newly licensed car drivers. The interview stages of the NZDS are linked to, the three licensing stages of the GDLS: learner, restricted and full. Baseline demographic (age, ethnicity, residential location, deprivation), personality (impulsivity, sensation seeking, aggression) and, behavioural data, (including pre-licensed driving behaviour), were obtained at the learner licence interview. Data on distance driven and crashes that occurred at the learner licence and restricted licence stages, were reported at the restricted and full licence interviews, respectively. Crash data were also obtained from police traffic crash report files and this was combined with the self-reported crash data. The analysis of the learner licence stage crashes, when only supervised driving is allowed, was based on the participants who had passed the restricted licence test and undertaken the NZDS, restricted licence interview (n = 2358). The analysis of the restricted licence stage crashes, when unsupervised driving is first allowed, was based on those who had passed the full licence test and completed the full licence interview (n = 1428).

Results

After controlling for a range of demographic, personality, behavioural variables and distance driven, Poisson regression showed that the only pre-licence driving behaviour that showed a consistent relationship with subsequent crashes was on-road car driving which was associated with an increased risk of being the driver in a car crash during the learner licence period.

Conclusion

This research showed that pre-licensed driving did not reduce crash risk among learner or restricted licensed drivers, and in some cases (such as on-road car driving) may have increased risk. Young people should be discouraged from the illegal behaviour of driving a car on-road before licensing.  相似文献   
9.
Reports 4 experiments concerning the effect of repetition on rated truth (the illusory-truth effect). Statements were paired with differentially credible sources (true vs false). Old trues would be rated true on 2 bases, source recollection and statement familiarity. Old falses, however, would be rated false if sources were recollected, leaving the unintentional influence of familiarity as their only basis for being rated true. Even so, falses were rated truer than new statements unless sources were especially memorable. Estimates showed the contributions of the 2 influences to be independent; the intentional influence of recollection was reduced if control was impaired, but the unintentional influence of familiarity remained constant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
This paper uses definitions of a consensus conference (ACCP/CCM) describing the epidemiology of SIRS, sepsis and septic shock in surgical ICU patients. During a period of 2 years a total of 656 patients were prospectively enrolled into the study. 335 patients (51.1% of the total population) developed SIRS (systemic inflammatory response syndrome); in 65 of these patients infection could be documented, i.e. they met the criteria of sepsis, 47 of these 65 septic patients developed septic shock, with mortality of 53.2%. SIRS is associated with a high sensitivity but a low specificity in predicting the outcome of ICU patients. Moreover, SIRS and sepsis appear to be of minor clinical relevance. On the contrary, septic shock describes a very high risk group of patients which should be characterized more closely in future studies.  相似文献   
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