关于Fuzzy信息系统的Rough集理论的一个注记

设(U,R)是Fuzzy相似的信息系统,若R_i∈R(i=1,2),则对于任意X U,有apr_(R_1YR_2)(X)=apr_(R_1)(X)Yapr_(R_2)(X0和apr_(R_1YR_2)(X)=apr_(R_1)(X)I apr_(R-2)(X)

关于必然命题种类的探讨

必然命题是逻辑学中一类重要命题,自从有了可能世界的理论,关于必然命题种类的探讨越来越深入、具体。本文初步探讨了关于必然命题的一些主要种类。

小学数学教材难点知识的特征

小学数学教材难点知识的特征学生在学习知识过程中感到理解困难，推理滞涩，思维易出偏差，这样的知识是教材的难点。具体来说，下列知识可确定为难点：一、抽象性很强的知识；二、推理步骤多的知识；三、综合性强的知识；四、学生接触少的知识。（摘自《山东教育》１９９...

高中课本《立体几何》中一个问题的质疑

在高级中学课本《立体几何》全一册第24、25页中,有直线和平面垂直的性质定理:如果两条直线同垂直于一个平面,那么这两条直线平行.关于这个定理教材上是这样论证的:(下图A)已知:a⊥α,b⊥α.求证:a∥b,证明 假定b与a不平行.设b∩a=O.b′是经过O与直线(?)平行的直线,∵a∥b′,a⊥α,∴b′⊥a.经过同一点O的两条直线b、b′都垂直于平面a是不可能的,因此,b∥a.

Spatial Scale Effects of Water Erosion Dynamics:Complexities, Variabilities, and Uncertainties

Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.

Analysis of LULUCF Accounting Rules after 2012

Land use, land-use change and forestry （LULUCF） activities can allow Annex I parties in the Kyoto Protocol to decrease their carbon emission reduction pressure, and comparably expanding more emission space for their domestic industries and energy production. The loopholes resulted from LULUCF activity types and specific accounting methods are always argued among the different parties, particularly including harvested wood products, influences of force majeure, threshold values of the reference level, and gross-net or net-net accounting methods. For estimating uncertainties in accounting loopholes, and to avoid that developed countries take advantage of the account{ng loopholes of LULUCF to decrease their emission reduction pressure, the LULUCF data submitted from the main developed countries in Annex I, including EU 27, Canada, Japan, and Russia, were collected. According to the analysis of these data, the loopholes influence the accounting results of LULUCF. The results show that the uncertainty of harvested wood products is excessive. The carbon sink produced by LULUCF activities will increase averagely by at least 30% without force majeure. The threshold values of the reference level of carbon sink should be set to a higher level. The net-net accounting method might be more suitable for LULUCF after 2012.

Optimization of Routing Considering Uncertainties

A route optimization methodology in the frame of an onboard decision support/guidance system for the ship＇s master has been developed and is presented in this paper. The method aims at the minimization of the fuel voyage cost and the risks related to the ship＇s seakeeping performance expected to be within acceptable limits of voyage duration. Parts of this methodology were implemented by interfacing alternative probability assessment methods, such as Monte Carlo, first order reliability method （FORM） and second order reliability method （SORM）, and a 3-D seakeeping code, including a software tool for the calculation of the added resistance in waves of NTUA-SDL. The entire system was integrated within the probabilistic analysis software PROBAN. Two of the main modules for the calculation of added resistance and the probabilistic assessment for the considered seakeeping hazards with respect to exceedance levels of predefined threshold values are herein elaborated and validation studies proved their efficiency in view of their implementation into an on-board optimization system.

Accurate estimation of soil shear strength parameters

The cost and safety of geotechnical engineering are highly depending on the accuracy of soil shear strength parameters.There are three methods often used to estimate soil shear strength parameters,i.e.,moment method,3-sigma rule and linear regression method.In this study,the accuracy of these three methods is compared.Traditional linear regression method(LRM)can only offer the mean of shear strength parameters.Some engineers misuse the standard error of shear strength indexes as the standard deviations.Such misuse may highly underestimate the uncertainty and induce high risk to the geotechnical design.A modified LRM is proposed to determine both the mean and variance of shear strength parameters.The moment method,three-sigma rule and LRM are used to analyze the tri-axial test data in Xiaolangdi Hydraulic Project and three numerical shear strength tests.The results demonstrate that:1)The modified LRM can offer the most accurate estimation to shear strength parameters;2)A dimensionless formula is much preferred in LRM rather than a dimensional formula.The stress ratio formula is much better than stress relation in the shear strength parameter analysis.The proposed method is applicable to shear strength parameter analysis for tri-axial test data,direct shear test and the un-drained shear strength test of stratified clay.

Some Peculiarities of the Preprocessing of Spectral Data and Images

Remotely sensed spectral data and images are acquired under significant additional effects accompanying their major formation process, which greatly determine measurement accuracy. In order to be used in subsequent quantitative analysis and assessment, this data should be subject to preliminary processing aiming to improve its accuracy and credibility. The paper considers some major problems related with preliminary processing of remotely sensed spectral data and images. The major factors are analyzed, which affect the occurrence of data noise or uncertainties and the methods for reduction or removal thereof. Assessment is made of the extent to which available equipment and technologies may help reduce measurement errors.

Robust reliable H_∞ control for a class of uncertain time-delay systems

This paper deals with the problem of robust reliable H∞ control for a class of uncertain nonlinear systems with time-varying delays and actuator failures. The uncertainties in the system are norm-bounded and time-varying. Based on Lyapunov methods, a sufficient condition on quadratic stabilization independent of delay is obtained. With the help of LMIs (linear matrix inequalities) approaches, a linear state feedback controller is designed to quadratically stabilize the given systems with a H∞ performance constraint of disturbance attenuation for all admissible uncertainties and all actuator failures occurred within the prespecified subset. A numerical example is given to demonstrate the effect of the proposed design approach.

THE UNCERTAINTY OF THE MINING ENGINEERING AND ITS APPLICATION

There are a lot of uncertainties in the mining engineering, and they make a notable impact on the engineering. The uncertainties of the physical and mechanical properties of geotectonic mass, the surrounding rock stability, the nature condition, the equipment operation, the personnel and the external environment are proposed and described. The stochastic analysis should be widely used for considering the impacts of the uncertainty on the mining engineering. The economical risk analysis and the stochastic index system should also be set up in the mining engineering.

A Method for Structuring Service Failure Factors to Realize Highly Reliable Services

As the society matures, customer requirements have become more varied. Services have been attracting increasing attention from industry and academic field as an effective mean to satisfy such varied customer requirements. In order to make a profit, it is important for companies to build and maintain long-term relationships with customers. Therefore, service providers should maintain their service quality and always satisfy their customers. To realize highly reliable product or services, in general, it is an effective approach to prevent failures from occurring in the use phase. Therefore, it is necessary that analysts identify the factors that could cause service failure and take appropriate measures against the target failure factor in advance. However, service failure factors are varied compared to physical products because service failures occur due to uncertainty elements such as human factors. In this study, we aim to enable service analysts to identify the critical failure factor from a number of failure factors. To achieve this, we identify complex failure factors and relationships among them from the viewpoint of the field where the service provided. This paper proposes a method for structuring the causal sequence between service failure factors by using a method of system modeling.

Experimental Small Scale Solar Power Tower in Iraq

Solar energy is the most available, clean and inexpensive source of energy among the other renewable sources of energy. This work deals with experimental steady to determent the performance of solar tower steam production for power generation. Designed and fabricated of a solar tower, consist of a central receiver tank （0.4 m × 0.6 m × 1.0 m） and 150 heliostat mirrors arranged around it. The central tank was made of galvanized steel. Each heliostat consisted of two （0.5 m × 0.5 m） mirrors. The results of this work produce steam at temperature 110 ℃. Large steam quantity could be obtained when using large scale experimental. The results of the work give good indication for application of solar energy to produce power in Iraq.

A Spatio-Temporal Odyssey Around the Concepts of Sustainable Development and Corporate Social Responsibility： Boundaries to Be Determined？

The aim of this research is to analyze the emergence of the concepts of sustainable development （SD） and corporate social responsibility （CSR） in companies in time and space. A spatio-temporal reading will indicate the most important socio-political and environmental events that have emerged with these two concepts. In order to complete the odyssey, a spatio-temporal analysis has retraced the epistemological evolution of these latter, whilst at the same time remarking the appropriation that has been made by the different institutional and organizational actors. The historical and epistemological reviews tell us that these two concepts, which came into existence almost 80 years, have indefinite outlines; one can be substituted for the other. However, thanks to this odyssey, we have reduced the boundaries even further between sustainable development and social responsibility and shown their theoretic and historical association. The perspective adopted shows that the concept of corporate social responsibility is closely connected to that of sustainable development. This connection means that researchers in management science are faced with more new problem issues reaching further than the simple lack of conceptual consensuses.

基于要素分析方法的项目成本估算风险评价

由于信息不充分而导致的项目成本估算风险是十分常见的。为有效规避目前实际工作中主要依赖估算师个人经验进行风险量化评价所存在的“估算师感觉各异”的弊端,本文基于要素分析方法建立了以“估算可确定度评价”为核心内容的项目成本估算风险量化决策模式,并结合业界对项目成本估算风险的一般性认识推导出其相应的数学模型。

浅议商除法估商

珠算商除的重点和难点又在于估商，估商的快慢直接影响到除法运算的速度。在很多教材中关于估商方法的讲述不是过于简单，就是有一套复杂的口诀或公式，使学生一时又很难掌握。本人以前曾经是一名珠算比赛选手，后来又从事珠算教育工作，在长期的珠算训练和教学实践中，摸...

where引导从句面面观

一、where引导的各类从句请仔细读下列句子,明确where从句在具体句子中的含义及从句性质:1.Iwonderwherehelives.2.Shewalkeduptowherehestood.3.Itmakesnodifferencewhereweshallhavethemeeting.4.That’swhereyouaremistaken.5.Shewouldliketoliveinacountrywhereitneversnows.6.Wherethere’8norain,farmingisdifficultorimpossible.7.Wheremostpeoplesawnothingbutahardenedcriminal。

Quantitative deterministic versus probability analyses based on a safety margin criterion

This paper proposes a new criterion called the ratio of safety margin(RSM)for use in the areas of the global factor of safety,reliability and limit states analyses with reference to their respective allowable criteria.An equation for calculating RSM based on the reliability index is formulated.Efforts for proving the applicability of this criterion include a theoretical demonstration in a simple one-variable case;an investigation on a test problem involving two random variables,followed by a slope stability study on a 156 m high embankment dam and an illustrative example presented in a EuroCode 7 guidebook.Calculation of the ratios of safety margin in the three areas provides a quantitative way to accommodate the analytical results within the same theoretical framework and makes the outcomes mutually comparable and supportive,which is much more enlightening than that would be the case by considering only one of them.Calculating RSMs for reliability and limit states methods has also helped solve the key issue concerning the uniqueness of the partial factors calibrated from a particular‘target case’.