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251.
Error is protean, ubiquitous and crucial in scientific process. In this paper it is argued that understanding scientific process requires what is currently absent: an adaptable, context-sensitive functional role for error in science that naturally harnesses error identification and avoidance to positive, success-driven, science. This paper develops a new account of scientific process of this sort, error and success driving Self-Directed Anticipative Learning (SDAL) cycling, using a recent re-analysis of ape-language research as test example. The example shows the limitations of other accounts of error, in particular Mayo’s (Error and the growth of experimental knowledge, 1996) error-statistical approach, and SDAL cycling shows how they can be fruitfully contextualised.  相似文献   
252.
There has been an increasing interest in integrating decision support systems (DSS) and expert systems (ES) to provide decision makers a more accessible, productive and domain-independent information and computing environment. This paper is aimed at designing a multiple expert systems integrated decision support system (MESIDSS) to enhance decision makers' ability in more complex cases. The basic framework, management system of multiple ESs, and functions of MESIDSS are presented. The applications of MESIDSS in large-scale decision making processes are discussed from the following aspects of problem decomposing, dynamic combination of multiple ESs, link of multiple bases and decision coordinating. Finally, a summary and some ideas for the future are presented.  相似文献   
253.
Fuzzy technology is a newly developed discipline based on fuzzy mathematics. In the recent years, it has been successfully applied into many areas, such as process control, diagnosis,evaluation, decision making and scheduling, especially in simulation where accurate mathematical models can not or very hard be established. In this paper, to meet the demands of fuzzy simulation, two fuzzy nets will first be presented, which are quite suitable for modeling the parallel or concurrent systems with fuzzy behavior. Then, a concept of active simulation will be introduced, in which the simulation model not only can show its fuzzy behavior, but also has a certain ability which can actively perform many very useful actions, such as automatic warning, realtime monitoring, simulation re-sult checking, simulation model self-adapting, error recovery, simulating path tracing, system states inspecting and exception handling, by a unified approach while some specified events occur. The simulation model described by this  相似文献   
254.
Computer simulation models may by used to gain further information about missile performance variability. Model validation is an important aspect of the test program for a missile system. Validation provides a basis for confidence in the model's results and is a necessary step if the model is to be used to draw inference about the behavior of the real missile. This paper is a review of methods useful for validation of computer simulation models of missile systems and provides a new method with high degree of confidence for validation of computer simulation models of missile systems. Some examples of the use of the new method in validating computer simulation models are given.  相似文献   
255.
The paper studies some important issues concerning the classification of industrialregions at the county-level by using methods of correlation-principal component analysis and fuzzycluster technique.According to reality it also gives a case study in which the connty-level industrialregional classification is simulated.  相似文献   
256.
This paper describes the context and the systemic experiential theories that have informed the praxis of educating agricultural systems practitioners. The praxis has involved a process of action research with students and with clients in farming and other rural community organizations. The praxis encourages learners to bring a range of methodologies of inquiry to bear upon problematic issues, contingent upon the nature of such issues. Informed by a number of different theories, and by reflecting on our own work, an earlier model of a nested hierarchy of systems of inquiry has been reconstructed to become a more useful guide to educational strategies: Each contingent methodology can now be seen to have its own learning, meta-learning, and epistemic learning dimensions. A key to enriched learning for responsible changes in agriculture and rural development lies in the facilitation of the consciousness of, and competency at, such a systemic pluralism of methodologies.  相似文献   
257.
258.
刘婷  王汝成  陆现彩  李娟  胡欢 《科学通报》2009,54(5):624-631
金属硫化物矿山开发引发的重金属污染已成为当前急需解决的环境问题. 以南京栖霞山铅锌矿采矿巷道壁上的现代钙华为研究对象, 利用电子探针、扫描电子显微镜和X射线粉末衍射分析等矿物学手段, 分析了钙华中的矿物组成及其重金属元素的赋存形态和分布状况. 结果表明钙华的主要矿物成分为方解石. 尽管地层水的重金属含量较低, 但是钙华中碳酸盐矿物的微量元素含量却较高, 最高含量分别为: Mn 23.65%, Zn 9.60%, Mg 0.76%, Fe 4.44%和Pb 0.66%. 钙华在电子探针背散射电子像中呈现出复杂的韵律壳层构造, 成分分析表明这种韵律壳层构造与重金属的分布有关. 另外, 在钙华中见有螺旋状及团絮状物质可能表明微生物参与了钙华的形成过程, 并与重金属的富集存在关联. 所报道的高度富锌-锰方解石对矿山环境中的重金属污染治理具有可借鉴意义.  相似文献   
259.
When atoms in a gas are cooled to extremely low temperatures, they will-under the appropriate conditions-condense into a single quantum-mechanical state known as a Bose-Einstein condensate. In such systems, quantum-mechanical behaviour is evident on a macroscopic scale. Here we explore the dynamics of how a Bose-Einstein condensate collapses and subsequently explodes when the balance of forces governing its size and shape is suddenly altered. A condensate's equilibrium size and shape is strongly affected by the interatomic interactions. Our ability to induce a collapse by switching the interactions from repulsive to attractive by tuning an externally applied magnetic field yields detailed information on the violent collapse process. We observe anisotropic atom bursts that explode from the condensate, atoms leaving the condensate in undetected forms, spikes appearing in the condensate wavefunction and oscillating remnant condensates that survive the collapse. All these processes have curious dependences on time, on the strength of the interaction and on the number of condensate atoms. Although the system would seem to be simple and well characterized, our measurements reveal many phenomena that challenge theoretical models.  相似文献   
260.
Brane new world.     
R Pease 《Nature》2001,411(6841):986-988
  相似文献   
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