考虑风险因素的房地产投资效益评价方法研究

传统的房地产投资效益评价方法由于没有考虑风险因素,已经很难适应竞争日趋激烈的房地产市场要求。本文在对传统的房地产投资效益评价方法分析的基础上,引入了风险变异系数和投资的系统风险度,修正了基准收益率及净现值的计算公式,提出了考虑风险因素的房地产投资效益评价方法。该方法将定性与定量分析相结合,充分吸取专家和房地产开发商的经验,能够更好地把握房地产投资效益的评价。最后,本文通过一个实例证明了本方法的科学性和现实指导意义。

Operative link for gastritis assessment vs operative link on intestinal metaplasia assessment

AIM:To compare the reliability of gastritis staging sys-tems in ranking gastritis-associated cancer risk in a large series of consecutive patients.METHODS:Gastric mucosal atrophy is the precancer-ous condition in which intestinal-type gastric cancer(GC)most frequently develops.The operative link for gas-tritis assessment(OLGA)staging system ranks the GC risk according to both the topography and the severity of gastric atrophy(as assessed histologically on the ba-sis of the Sydney protocol for gastric mucosal biopsy).Both cross-sectional and long-term follow-up trials have consistently associated OLGA stages Ⅲ-Ⅳ with a higher risk of GC.A recently-proposed modification of the OLGA staging system(OLGIM)basically incorporates the OLGA frame,but replaces the atrophy score with an assessment of intestinal metaplasia(IM)alone.A series of 4552 consecutive biopsy sets(2007-2009)was re-trieved and reassessed according to both the OLGA and the OLGIM staging systems.A set of at least 5 biopsy samples was available for all the cases considered.RESULTS:In 4460 of 4552 cases(98.0%),both the high-risk stages(Ⅲ + Ⅳ)and the low-risk stages(0 +Ⅰ + Ⅱ)were assessed applying the OLGA and OL-GIM criteria.Among the 243 OLGA high-risk stages,14(5.8%)were down-staged to a low risk using OLGIM.The 67(1.5%)incidentally-found neoplastic lesions(intraepithelial or invasive)were consistently associated with high-risk stages,as assessed by both OLGA and OLGIM(P < 0.001 for both).Two of 34 intestinal-type GCs coexisting with a high-risk OLGA stage(stage Ⅲ)were associated with a low-risk OLGIM stage(stage Ⅱ).CONCLUSION:Gastritis staging systems(both OLGA and OLGIM)convey prognostically important informa-tion on the gastritis-associated cancer risk.Because of its clinical impact,the stage of gastritis should be included as a conclusive message in the gastritis histol-ogy report.Since it focuses on IM alone,OLGIM staging is less sensitive than OLGA staging in the identif ication of patients at high risk of gastric cancer.

Decision Support Scheme for Lishan Landslide Prewarning System

This study combines the analytical model to build a landside monitoring decision support system of the Web GIS. The landslide area of Lishan is a case study for the research. The analysis of the risk degree for the landslide area in Lishan is based on the three-layer architecture of Fuzzy Analytic Hierarchical Process （FAHP）. There are four fuzzy model structures used in monitoring devices： rainfall, groundwater level, Time Domain Reflectometry （TDR） monitored the subsurface deformation, and Global Positioning System （GPS） monitored ground displacement. These structures are relative to four membership functions that are used to classify four states, including safety, attention, warning, and danger. The risk degree of the landslide area can be obtained through the fuzzy rules by determining management criteria. Calculating the total scores of historical monitoring record of the rainfall, groundwater level, TDR, and GPS through the fuzzy theory can determine the analytical results of risk degrees in Lishan landslide area. In this whole area, management criterion is in the state of attention when the total score is larger than 72, in the state of warning when total score is larger than 95, and in the state of danger when total score is larger than 113. The system provides real-time monitoring data, and prewarning decision support in order to announce and prevent the disaster at the earliest time.

Agricultural Drought Resisting and Hydrological-Ecological Changes Taking Hebei Province in North China as an Example

Drought is usually supposed to be a rainfall deficiency problem. Most studies and practices to mitigate drought disaster are focusing on water development and irrigation, while neglecting that the agriculture system is a compounded human-natural system. Drought situation and tendency is also driven by human coping strategies. This paper takes Hebei Province in north China as an example, studing the spirally interact process of drought resisting and hydrological ecological feedback. The result shows that large scale water projects construction facilitated irrigation. With improved irrigation, farmers enhanced multiple crop index and land-use intensity greatly and increased the sowing area of water consuming crop, winter wheat. At the same time, both crop yield and gross output are raising steadily. Water demand and depletion in agricultural system increase year by year. This gradually leads to highly dependent on over exploitation of water resources, especially overdraw of groundwater. The process deteriorated the stability of hydrological-ecological system and made the ecological environment drying up. Drying up environment is breeding greater vulnerability and risk of drought in the long term. For sustainable development, integrated drought risk management should be based on the balance between sustainable water supply and water demand. The key is to improve agricultural system＇s adaptive and resilient capacity to drought.

Research about Online Security Warning and Risk Assessment of Power Grid Based on Energy Management System

In this paper, online security warning and risk assessment of power grid are proposed, based on data from EMS （Energy Management System）, combined with information of real-time operation state, component status and external operating environment. It combines the two factors, contingency likelihood and severity, that determine system reliability, into risk indices on different loads and operation modes, which provide precise evaluation of the power grid＇s security performance. According to these indices, it can know the vulnerable area of the system and whether the normal operating mode or repair mode is over-limited or not, and provide decision-making support for dispatchers. Common cause outages and equipment-aging are considered in terms of the establishment of outage model. Multiple risk indices are defined in order to reflect the risk level of the power grid more comprehensively.

Gradients in predation risk in a tropical river system

The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.

Research Framework for Ecosystem Vulnerability:Measurement, Prediction, and Risk Assessment

The fragility of ecosystem health has become a key factor hindering the sustainable development of the ecological environment. Through a review of published research from domestic and foreign scholars, starting from the endogenous logic of studies in the field of ecosystem vulnerability(EV), this paper sorts out the literature on the aspects of measurement models, prediction methods and risk assessment, comprehensively defines the research category and scientific framework of EV, and analyzes the research ideas and development trends. We arrived at the following conclusions: 1) The connotation of ecosystem vulnerability not only embodies the change in the vulnerability of the natural environment, but it also reflects the irreversible damage to the ecosystem caused by excessive development and industrial production activities. 2) The setting of ecosystem vulnerability indices should aim to fully reflect the essential features of that vulnerability, which should include the index systems of natural, social, economic and other related factors. 3) There are many types of ecosystem vulnerability measurement methods, prediction models and risk evaluation models, which have different focuses and advantages. The most appropriate method should be adopted for conducting comprehensive and systematic evaluation, prediction and estimation according to the different representation and evolution mechanisms of the chosen research object and regional ecosystem vulnerability. 4) Based on the regional system characteristics, corresponding risk management measures should be proposed, and pertinent policy suggestions should be put forward to improve the ecological safety and sustainable development of an ecologically vulnerable area.