黄河三角洲地区太阳能开发利用问题审视

黄河三角洲地区拥有丰富的太阳能资源,其利用主要为太阳能集热器及光伏发电。但是太阳能的开发利用仍存在热利用形式单一、行业规范化不足,光伏产业链不完整、技术落后、产品市场培育落后于产业发展、光伏产业投资过于盲目、恶性竞争严重等问题,因此需要政府完善发展规划并提供政策支持,行业加强技术研发,完善产业体系,并提高公众消费意识,有效处理好政府、行业、用户之间的相互关系,促进黄河三角洲高效生态经济区建设。     

气水交替驱油藏注入能力分析及优化

针对注入能力降低是制约气水交替驱提高油藏采收率的关键因素的问题,以相似理论中的检验分析法推导了气水交替注入无因次注入能力方程,运用考虑相渗和毛管滞后效应耦合的数值模拟方法,评价无因次注入能力的因素影响,讨论并优化了注入水气比。研究结果表明：对于特定油藏体系,通过增加注入气的富化度提高粘滞力重力比来达到改善驱替效果的方法比片面地增加注气速度更高一些;水气比越高,达到相同开采效果所需气量越小,但因此而出现较明显的注入能力下降的趋势。对于低粘滞力重力比的注气条件,选择水气比为2最佳;而对于高粘滞力重力比,则水气比为1是最佳选择。建议在水气比的优选时充分结合油藏地质特征和注入流体特性进行分析。     

Functional Estimation of a Density Under a New Weak Dependence Condition

The purpose of this paper is to prove, through the analysis of the behaviour of a standard kernel density estimator, that the notion of weak dependence defined in a previous paper (cf. Doukhan & Louhichi, 1999) has sufficiently sharp properties to be used in various situations. More precisely we investigate the asymptotics of high order losses, asymptotic distributions and uniform almost sure behaviour of kernel density estimates. We prove that they are the same as for independent samples (with some restrictions for a.s. behaviours). Recall finally that this weak dependence condition extends on the previously defined ones such as mixing, association and it allows considerations of new classes such as weak shifts processes based on independent sequences as well as some non-mixing Markov processes.     

Boosting with Bayesian stumps

Boosting is a new, powerful method for classification. It is an iterative procedure which successively classifies a weighted version of the sample, and then reweights this sample dependent on how successful the classification was. In this paper we review some of the commonly used methods for performing boosting and show how they can be fit into a Bayesian setup at each iteration of the algorithm. We demonstrate how this formulation gives rise to a new splitting criterion when using a domain-partitioning classification method such as a decision tree. Further we can improve the predictive performance of simple decision trees, known as stumps, by using a posterior weighted average of them to classify at each step of the algorithm, rather than just a single stump. The main advantage of this approach is to reduce the number of boosting iterations required to produce a good classifier with only a minimal increase in the computational complexity of the algorithm.     

全球气候变化问题与我国能源战略

全球气候变化及相应的温室气体排放问题 ,越来越成为国际社会关注的焦点。文章分析了发达国家在气候变化问题上的历史责任 ,评价了自改革开放以来 ,我国能源政策对控制温室气体排放量增长的客观效果 ,对未来我国的能源消费和相应的CO2 排放的趋势进行了预测 ,分析了我国未来在温室气体排放问题上可能面临的压力 ,以及未来可能采取限控措施的代价和对宏观经济的影响 ,并对我国能源战略有关政策提出了进一步的建议。     

美国核能工业管制体系的演变及其借鉴分析

在原子时代的开端 ,核能的前途似乎是一片光明。在五六十年代的美国 ,核能经历了一个不受约束的扩张阶段。但是 ,随后公众的支持和经济利益转向了反对核能技术。从 70年代后期开始 ,美国公用事业公司再没有订购新的核电站。美国核能管制体系在决定核能命运的选择过程中扮演了一个没有预计到的重要角色。文章详细地描述了这个体系的演变历程 ,以及它在公众对核能的信心的消逝这个过程中所产生的影响 ,核能管制体系对公众的这种信心的影响主要有三个方面 :管制体系具有的促进和管制核能这两个目标之间的冲突、管制过程的保密以及一种幼稚的与大众沟通的策略     

高阶拟线性时滞差分方程非振动解的存在性与渐近性

考虑一类高阶拟线性时滞差分方程给出了存在无界非振动解的充要条件。     

煤炭消费、经济增长与废气排放：基于中国的实证研究

本文采用计量经济学中的协整理论考察我国煤炭消费与经济增长、烟尘排放、二氧化硫排放和工业粉尘排放之间的关系。结果显示,我国煤炭消费与经济增长以及二氧化硫和工业粉尘的排放量之间存在着长期协整关系。为此,建立了相应的长期均衡方程及误差修正模型,并根据本文的分析结论提出了实现中国经济-能源-环境和谐发展的措施。     

Combinatorial Optimization in Real-Time Scheduling: Theory and Algorithms

Real-time computer systems are essential for many applications, such as robot control, avionics, medical instrumentation, manufacturing, etc. The correctness of the system depends on the temporal correctness as well as the functional correctness of the task executions. In order to assure temporal correctness it is necessary that the resources be scheduled to meet the temporal requirements of applications. When we consider the problem of nonpreemptive scheduling of a set of tasks in a processor for which no feasible solution exists, some tasks may have to be rejected so that a schedule can be generated for the rest. In this paper, we consider the problem of generating an optimal schedule such that the number of rejected tasks is minimized, and then the finish time is minimized for the accepted tasks. We propose to use an analytic approach to solve this problem. We first discuss the super sequence based technique which was originally proposed for reducing the search space in testing the feasibility of a task set. Then we show by the Conformation theorem that the super sequence constructed from the task set also provides a valid and reduced search space for the optimization problem. While the complexity of our scheduling algorithm in the worst case remains exponential, our simulation results show that the cost is reasonable for the average case.     

中国需要大规模发展核电

预计到本世纪中叶,我国能源供应缺口将高达２０亿吨标煤左右,大规模发展核能是弥补这一缺口的途径之一。核能是清洁、安全的能源,核废料处置问题是可以解决的,核电在我国也具有经济竞争力。为促进我国的核能发展,建议实施下列政策：明确核能的战略地位和作用,采取符合国际核电发展趋势的核电技术发展路线,加快核电的国产化,以科研为基础增强自主化能力,并及早关注公众可接受性问题。