我国能源-环境-经济系统的区域间建模

本研究试图探讨用“自上而下”和“自下而上”相结合的建模方法,对我国二氧化硫和二氧化碳减排进行区域间建模.本研究以一个用于分析硫税的区域间波及影响、以及评价电力部门的脱硫技术的区域间可计算一般均衡模型为基础平台;从理论上探讨了如何对该模型进行扩展和改进.首先本研究对该模型的要点进行了阐述,强调了把能源技术模型融合在区域间可计算一般均衡模型中的建模方法.然后本研究对于实行环境税和排放权交易的环境经济效果进行了比较,用成本收益法分析了工业部门对减排技术的选择,并以前述模型为基础建立了区域间模型.本研究所提出的模型可以被用来从区域统筹的观点,对我国能源-环境-经济系统的可持续发展进行预测和分析.最后本研究提出应该从更新数据、研究环境政策和技术进步之间的关系等方面,进一步发展该模型.     

与John基有关的三个等价等式及证明

John基在凸几何分析中占有重要的地位，在凸体空间关系的研究中起着重要的作用．本文研究了John基的基本性质，主要是通过研究与John基有关的三个等价等式，并证明它们的等价性．     

Simulation Study of an Automated Guided-vehicle System in a Yugoslav Hospital

A simulation study of an automated guided-vehicle system connected with an automated vertical transportation system in a large hospital is described. The aim of the study was to determine the allocation and size of storage space for vehicles, the minimum number of vehicles required, the accomplishment of a transportation-network timetable and the queueing situation in the system. This study is part of a simulation study of internal transportation in the new, 1100-bed University Hospital in Zagreb, Yugoslavia, which is under construction.     

Online study collaboration to improve teachers’ expertise in instructional design in mathematics

Online study collaboration is a recent professional development approach that goes beyond school and regional boundaries and even helps reach rural schools in China. In this study, we focused on a specific online study collaboration program to examine its potential benefits for improving participating teachers’ expertise in instructional design. Data were collected from the online study collaboration organizers and four main participating schools. The results reveal the program’s well-structured process and organization for planning and conducting the online study collaboration. Participating teachers benefited from their sharing and discussions with experts and other teachers. Their instructional designs show many important changes that are aligned with experts’ comments. Selected teachers’ expertise improvement includes their knowledge about the textbook and content, their perspectives about students’ learning and instruction, and their learning of different instructional approaches to engage students in classroom instruction. The use of online study collaboration for improving teachers’ expertise and the study’s limitations are then discussed.     

New method for estimating survival curves based upon subpopulations

The overall Kaplan-Meier estimate of the survival curve underlying a study population does not individually account for the ages at which patients were first seen and thence followed up in the study. Since the number of patients in these age-specific subgroups varies quite arbitrarily for a given study, the overall Kaplan-Meier curve which assumes that all patients were seen from the beginning of the study usually either overestimates or underestimates the survival probability, depending on the varying sample sizes. In this paper, we therefore propose an estimate of the overall survival curve underlying a study population based on the individual age-specific Kaplan-Meier estimates and the probability distribution of the age at which patients were first seen in the study. In the particular case when there is no censoring, it is shown that the usual overall Kaplan-Meier survival curve which assumes that all patients irrespective of their age at entry into the study were followed from the beginning of the study is identical with the proposed estimate. This result does not seem to necessarily hold good in the presence of arbitrary censoring. Further, the estimate is unbiased and consistent, a property which the Kaplan-Meier estimate also enjoys. The efficiency of the proposed estimate relative to the Kaplan-Meier estimate is being investigated and will be reported along with results of its application in a separate communication.     

统计学在证券期货市场中的应用(Ⅰ)

统计学在证券期货制场中的应用．本文较系统地介绍了统计学在证券期货市场中的应用,其中包括作者的一些最新研究成果,如：证券期货市场指标体系的研究;新华财经指数的编制;证券投资组合的研究与应用等     

Pre-service science teachers’ perceptions of mathematics courses in a science teacher education programme1

Most science departments offer compulsory mathematics courses to their students with the expectation that students can apply their experience from the mathematics courses to other fields of study, including science. The current study first aims to investigate the views of pre-service science teachers of science-teaching preparation degrees and their expectations regarding the difficulty level of mathematics courses in science-teaching education programmes. Second, the study investigates changes and the reasons behind the changes in their interest regarding mathematics after completing these courses. Third, the current study seeks to reveal undergraduate science teachers’ opinions regarding the contribution of undergraduate mathematics courses to their professional development. Being qualitative in nature, this study was a case study. According to the results, almost all of the students considered that undergraduate mathematics courses were ‘difficult’ because of the complex and intensive content of the courses and their poor background mathematical knowledge. Moreover, the majority of science undergraduates mentioned that mathematics would contribute to their professional development as a science teacher. On the other hand, they declared a negative change in their attitude towards mathematics after completing the mathematics courses due to continuous failure at mathematics and their teachers’ lack of knowledge in terms of teaching mathematics.     

纵向删失数据下线性模型的相合估计

医药临床试验,生存分析,可靠性统计等研究领域,由于考虑到时间和费用问题,研究往往有一定期限.因为研究到期的被迫结束或者某些病人中途退出试验,最后得到的试验结果往往是删失数据.对于删失数据,采用无偏转换的方法处理,方法的最大优点是得到的估计量为显式解.首先讨论了在纵向右删失数据下线性回归模型回归系数估计的均方相合性,并且把结论推广到了污染线性模型,得到了污染系数、回归系数的强相合估计.     

统计方法在研究微积分与后续课程相关性中的应用与实证分析

着眼于本科生后期专业课程的学习效果,探讨微积分课程学习效果的有效性.以北京理工大学某经管类专业全部学生大一大二两学年的学习成绩为依据,分析微积分课程学习与后续理科课程学习的相关性,提出评估微积分课程学习效果的量化指标θ值的概念,并基于回归分析和相关性分析给出其算法.在实例分析中,通过研究,发现学生微积分课程学习效果的好坏会影响他们对后续相关课程的学习,同时也发现学生将微积分知识运用到间接相关科目的能力比运用到直接相关的科目的能力薄弱.     

基于结构方程模型的市场细分方法应用研究

结构方程模型是当前研究顾客满意和顾客忠诚的主流方法之一,但基于结构方程对顾客满意和顾客忠诚进行市场细分方法的研究却十分缺乏.基于结构方程模型进行市场细分算法的应用研究,并对得出的细分结果进行了解释.     

Convergence rates for weighted sums in noncommutative probability space

We study convergence rates for weighted sums of pairwise independent random variables in a noncommutative probability space of which the weights are in a von Neumann algebra. As applications, we first study convergence rates for weighted sums of random variables in the noncommutative Lorentz space, and second we study convergence rates for weighted sums of probability measures with respect to the free additive convolution.     

Interactive group decision-making using a fuzzy linguistic approach for evaluating the flexibility in a supply chain

With global competition rapidly intensifying and shifting to the supply chain level, the supply chain flexibility has become increasingly important. However, the literature addressing supply chain flexibility remains limited. This study thus builds a group decision-making structure model of flexibility in supply chain management development. This study presents a framework for evaluating supply chain flexibility comprising two parts, an evaluation hierarchy with flexibility dimensions and related metrics, and an evaluation scheme that uses a three-stage process to evaluate supply chain flexibility. This study then proposes an algorithm for determining the degree of supply chain flexibility using a fuzzy linguistic approach. Evaluations of the degree of supply chain flexibility can identify the need to improve supply chain flexibility, and identify specific dimensions of supply chain flexibility as the best directions for improvement. The results of this study are more objective and unbiased for two reasons. First, the results are generated by group decision-making with interactive consensus analysis. Second, the fuzzy linguistic approach used in this study has more advantage to preserve no loss of information than other methods. Additionally, this study presents an example using a case study to illustrate the availability of the proposed methods and compare it with other methods.     

Classroom Response Systems: Effects on the Critical Analysis Skills of Students in Introductory Science Courses

College instructors often teach scientific thinking by asking students to review and analyze a primary research article. The main purpose of this study was to explore how classroom response systems (CRS) could help impact the quality of written analysis papers submitted for this assignment by students taking 100‐level biology courses at a medium‐sized suburban, two‐year college in the northeastern United States. Students in all participating course sections received written instructions on five key elements of critical analysis (CA) to include in scientific study analysis papers. Classroom instruction on recognizing these key elements in primary research papers was provided either via CRS or via an instructor‐facilitated classroom discussion enhanced by the same PowerPoint presentation. A rubric, designed specifically for this assignment, was validated prior to its use in this study. Fifty students participated in the study, and those who received the CRS intervention achieved significantly higher CA scores for identifying implications of study findings, while the group that received only written instructions achieved significantly higher CA scores for discussing the credibility of the references used by the authors in planning the critiqued study. The implications of this study are discussed along with ideas for future research.     

Homotopy and semisymmetry of quasigroups

The study of quasigroup homotopies reduces to the study of homomorphisms between semisymmetric quasigroups. In particular, the study of homotopies between central quasigroups reduces to the study of homomorphisms between entropic semisymmetric quasigroups. Received December 20, 1996; accepted in final form September 17, 1997.     

Plane transformations in a complex setting III: similarities

This is the third part of a study of plane transformations described in a complex setting. After the study of homotheties, translations, rotations and reflections, we proceed now to the study of plane similarities, either direct or inverse. Their group theoretical properties are described, and their action on classical geometrical objects is studied.     

中国上市公司资本结构影响因素之实证研究

资本结构不仅是财务理论研究中的热点及难点,也日益成为公司理财决策的关键问题.本文从影响因素角度对资本结构进行实证研究.文中以深沪两市部分非金融类上市公司为样本,利用本世纪最初三年的企业财务数据,选取可能影响企业资本结构的多个指标为解释变量,利用单因素方差分析、主成分分析、逐步回归分析找出了主要影响因素及其影响方式,试图为国内上市公司资本结构决定因素提供最新实证研究证据,并为企业财务决策提供支持.     

Discrete-Euclidean operations

In this paper, we study the relationship between Euclidean and discrete space. We study discrete operations based on Euclidean functions: discrete smooth scaling and discrete-continuous rotation. Conversely, we study Euclidean operations based on discrete functions: the discrete based simplification, the Euclidean-discrete union and the Euclidean-discrete co-refinement. These operations operate partly in discrete, and partly in continuous space. Especially for the discrete smooth scaling operation, we provide error bounds when such different operations are chained.     

高频金融数据“日历效应”的小波神经网络模型分析

高频金融数据的分析与建模是金融计量学的一个全新的研究领域.高频数据"日历效应"是金融市场微观结构研究领域的重要发现,但是金融市场微观结构理论主要是从定性的角度研究"日历效应".如何定量地刻画高频数据"日历效应"是进一步深入理解金融市场的关键.论文提出用小波神经网络(WNN)来定量研究高频金融数据"日历效应",实证研究表明小波神经网络(WNN)很好地刻画了"日历效应".     

S.Earnshow的早期孤立波研究及其重要影响

通过文献考证方法分析考察S.Earnshow 1845年关于孤立波理论的论文.Earnshaw以罗素试验结果为基本假设,建立了一个虽有缺陷但却是Stokes早期有关研究的出发点的非线性理论.Earnshaw的崭新思路昭示了孤立波理论研究的正确方向,并为一般科学理论研究提供了值得借鉴的思想方法.