极端化策略在解决函数问题中的应用

利用问题中的极端情形分析解决问题的方法称之为极端化策略.极端化策略的优势在于能够将复杂的问题转化为浅显易懂的问题,从而达到事半功倍的解题效果.极端化策略是解决函数问题的有效方法,在解决问题的过程中,教师需关注学生的学习过程,为学生提供简便直观的解题思路,提高学生的解题能力.文章从数形结合、约束条件、求解区间三个角度入手,分析极端化策略在解决函数关系问题中的应用.

自我建构与新产品极端—折中评价策略的选择

创新性产品可以给消费者带来利益,却往往面临更高的失败风险。企业只有深入了解消费者产品效价不一致情况下的评价策略,才能选取适当的营销工具进行有针对性的干预,从而改善消费者对新产品的评价并提升品牌形象,推动品牌建设进入良性循环。通过两个实验探究不同自我建构消费者在新产品与品牌效价不一致时进行信息加工、形成产品评价的异同机理发现,在低涉入度条件下,受不同自我建构个体精细加工差异的影响,独立我完全依据产品属性信息做出评价(极端策略),依存我同时依据品牌和属性信息做出评价(折中策略)。而导致上述结果的主要原因在于独立我与依存我不同的评价策略,而非两者对品牌诊断性的知觉差异。因此,对大量正处于成长期的我国企业而言,一定要根据具体销售情境,借助适当的营销工具(广告、包装等)营造高涉入度的消费情境,以此提升消费者评价和品牌形象,构筑企业持续竞争优势。

建设韧性城市:应对极端气候的重要策略

随着全球气候变暖,包括极端高温、极端暴雨、极端干旱等各种极端天气呈现持续性、破纪录、复合性和群发性的新特征。极端天气可能引发一系列灾害风险,对人民群众的生命财产安全、城市的正常运转及经济发展构成严峻挑战。加快建设韧性城市,提高应对极端天气的能力和水平,成为当下世界各国和各大中型城市的共同战略选择。从风险评估、设施完善、预警预报、应急保障等方面推动韧性城市建设,是有效提高城市应对极端气候灾害的重要策略。

基于RSS-ERT的智能决策系统在涡轴涡桨发动机控制系统机械液压产品试验领域的设计与应用

控制系统机械液压产品是涡轴涡桨发动机控制指令的重要执行元件,其生产装配完成后需要使用专用试验设备进行性能调试,调试合格后方可装配发动机。由于控制系统机械液压产品结构复杂,调试过程烦琐,对试验操作人员的技术水平要求较高,须构建一套基于放回取样策略-极端随机树(Return Sampling Strategy-Extreme Random Tree,RSS-ERT)的智能决策系统。通过在调试过程中采集试验数据并根据产品性能反馈调试决策,降低了调试过程对试验操作人员的技术依赖,提高了调试效率。选取某型号燃油调节器进行系统功能验证,结果表明智能决策功能反馈准确,能够满足使用需求。

Life in extreme environments: Approaches to study life-environment co-evolutionary strategies

The term ＂extreme environments＂ describes the conditions that deviate from what mesophilic cells can tolerate. These condi- tions are ＂extreme＂ in the eye of mankind, but they may be suitable or even essential living conditions for most microorgan- isms. Hypertherrnophilic microorganisms form a branch at the root of the phylogenetic tree, indicating that early life originated from extreme environments similar to that of modern deep-sea hydrothermal vents, which are characterized by high-tempera- ture and oxygen-limiting conditions. During the inevitable cooling and gradual oxidation process on Earth, microorganisms developed similar mechanisms of adaptation. By studying modem extremophiles, we may be able to decode the mysterious history of their genomic evolution and to reconstruct e~,rly life. Because life itself is a process of energy uptake to maintain a dissipative structure that is not in thermodynamic equilibrium, the energy metabolism of microorganisms determines the path- way of evolution, the structure of an ecosystem, and the physiology of cells. ＂Following energy＂ is an essential approach to understand the boundaries of life and to search for life beyond Earth.

Influence of extreme weather and meteorological anomalies on outbreaks of influenza A (H1N1)

Biological experiments and epidemiological evidence indicate that variations in environment have important effect on the occurrence and transmission of epidemic influenza.It is therefore important to understand the characteristic patterns of transmission for prevention of disease and reduction of disease burden.Based on case records,we analyzed the environmental characteristics including climate variables in Changsha,and then constructed a meteorological anomaly susceptive-infective-removal (SIR) model on the basis of the results of influenza A (H1N1) transmission.The results showed that the outbreak of influenza A (H1N1) in Changsha showed significant correlation with meteorological conditions;the spread of influenza was sensitive to meteorological anomalies,and that the outbreak of influenza A (H1N1) in Changsha was influenced by a combination of absolute humidity anomalous weather conditions,contact rates of the influenza patients and changes in population movements.These findings will provide helpful information regarding prevention strategies under different conditions,a fresh understanding of the emergence and re-emergence of influenza outbreaks,and a new perspective on the transmission dynamics of influenza.

The Role of Local Knowledge in the Risk Management of Extreme Climates in Local Communities:A Case Study in a Nomadic NIAHS Site

In the context of climate change,research on extreme climates and disaster risk management has become a crucial component of climate change adaptation.Local communities,which have been facing extreme climates for a long time in their production and daily life,have developed some locally applicable traditional knowledge that has played an important role in their adaptation to extreme climate and disaster risk management.Therefore,this research aims to link Local knowledge(LK)to community extreme climate disaster risk management in order to construct a conceptual model.It then takes the extreme climate adaptation strategy of traditional nomads in a temperate grassland of China as an example to analyze the role of LK in extreme climate adaptation using the proposed theoretical framework.The main research objectives of this study are:(1)To construct a conceptual model to illustrate the relations among extreme climate events,risk management,LK,and farmers’adaptation strategies;(2)To apply the theoretical framework to a field case to reveal context-specific extreme climate adaptation mechanisms with LK as a critical component;(3)To test the framework and provide suggestions for the extreme climates adaptation,and the conservation of LK related to climate change adaptation.The results show that from the perspective of disaster risk management,local communities could manage extreme climates as a disaster risk through adaptation strategies formed from LK,because as a knowledge system,LK contains relevant knowledge covering the whole process of disaster risk management.

The influence of anthropogenic climate change on wet and dry summers in Europe

Understanding the role of anthropogenic forcings in regional hydrological changes can help communities plan their adaptation in an informed manner.Here we apply attribution research methods to investigate the effect of human influence on historical trends in wet and dry summers and changes in the likelihood of extreme events in Europe.We employ an ensemble of new climate models and compare experiments with and without the effect of human influence to assess the anthropogenic contribution.Future changes are also analysed with projections to year 2100.We employ two drought indices defined relative to the pre-industrial climate:one driven by changes in rainfall only and one that also includes the effect of temperature via changes in potential evapotranspiration.Both indices suggest significant changes in European summers have already emerged above variability and are expected to intensify in the future,leading to widespread dryer conditions which are more extreme in the south.When only the effect of rainfall is considered,there is a distinct contrast between a shift towards wetter conditions in the north and dryer in the south of the continent,as well as an overall increase in variability.However,when the effect of warming is also included,it largely masks the wet trends in the north,resulting in increasingly drier summers across most of the continent.Historical index trends are already detected in the observations,while models suggest that what were extremely dry conditions in the pre-industrial climate will become normal in the south by the end of the century.