应用型本科机械设计制造及自动化专业人才培养方案研究

本文针对应用型本科机械设计制造及其自动化专业如何培养当今社会急缺的高技能复合型人才问题作了探索与研究,提出了新的课程体系与培养方案。     

Towards Enhancement of the Economy of a Thermal Power Generating System through Prediction of Plant Efficiency

The plant ‘Heat Rate’ (HR) is a measure of overall efficiency of a thermal power generating system. It depends on a large number of factors, some of which are non-measurable, while data relating to others are seldom available and recorded. However, coal quality (expressed in terms of ‘effective heat value’ (EHV) as kcal/kg) transpires to be one of the important factors that influences HR values and data on EHV are available in any thermal power generating system. In the present work, we propose a prediction interval of the HR values on the basis of only EHV, keeping in mind that coal quality is one of the important (but not the only) factors that have a pronounced effect on the combustion process and hence on HR. The underlying theory borrows the idea of providing simultaneous confidence interval (SCI) to the coefficients of a p-th p(≥1) order autoregressive model (AR(p)). The theory has been substantiated with the help of real life data from a power utility (after suitable base and scale transformation of the data to maintain the confidentiality of the classified document). Scope for formulating strategies to enhance the economy of a thermal power generating system has also been explored.     

关于学报发展中几个问题的思考

在互联网日益普及的情况下，高校学报不应等待观望，而应尽快转变认识，充分利用网络资源进行新的尝试，为自身的发展服务。高校学报要走的个性化特色化之路，通过对可资形成特色的各种条件进行创造性整合，形成刊物的个性与特色。注重提高刊物的学术影响力，提高所刊论文的引用率与引文率，在增强社会效益上做文章。同时，也要重视编排的标准化、规范化等工作，以期使学报的生存与发展进入良性循环。     

科技创新是现代化高校发展的重要标志

近年来,高校作为国家科技创新体系的重要组成部分,大力加强科学研究。北京大学让本科生提前介入科研,培养科研创新能力。高校创办的具有特色的大学科技园、高科技产业群,逐步发展成为普遍趋势,高校已经成为中国基础研究的主力军。高校现有的人才资源有效结合起来,就形成一批充满活力的科技创新集体。     

A simple procedure for the selection of significant effects

Summary.  Given a large number of test statistics, a small proportion of which represent departures from the relevant null hypothesis, a simple rule is given for choosing those statistics that are indicative of departure. It is based on fitting by moments a mixture model to the set of test statistics and then deriving an estimated likelihood ratio. Simulation suggests that the procedure has good properties when the departure from an overall null hypothesis is not too small.     

Statistical Analyses and Modelling of the Mixing Process of Euro Coins in Germany and Europe

This paper reports on the mixing of Euro coins from different countries of origin in Europe, which started on 1 January 2002. There is an interesting conclusion: that the mobility of small and large denominations is different. The long‐term behaviour of the mixing process is studied using a simple deterministic model and data from Germany, France and the Netherlands. The analysis leads to predictions about the future progress of the mixing process.     

中国就业市场中的性别歧视——对公众认知率的研究

调查结果表明:女性更关注工作过程中的性别歧视和职业隔离的性别歧视现象,女性仅对应聘过程中的性别歧视现象如女性的相貌、身高等要求、外来打工妹的应聘两个问题的认知率高于男性;女性对性骚扰性别歧视认知率与男性没有显著差异;公众对各种性别歧视现象的总体认知水平不高.     

关于人民币汇率问题的几点思考

人民币汇率不存在被严重低估的问题 ,升值没有客观必然性。目前人民币升值面临巨大压力 ,其主要原因在于我国不合理的外部均衡结构。人民币在未来也不会很快呈现出不断升值的变化趋势 ,中长期内的汇率变动趋势尚有待于观察 ,贬值压力同样不可低估。维持人民币汇率较长时期的稳定 ,延缓升值进程的发生 ,具有非常重要的战略意义     

The analysis of incomplete data using stochastic covariates

In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.     

隆线溞(Daphnia carinata king)的呼吸代谢测定

本文用Winkler法测定隆线溞(Caphnia carinata king)不同龄期个体的耗氧量及二幼龄个体在不同温度下的耗氧量。测得幼龄与成龄两阶段,其耗氧量分别以4.88×10~(-2)与1.695×10~(-1)的速率随体重增加而增大,耗氧率则分别随体重的增加而逐渐降低;在常温下,隆线溞耗氧量Y与温度X呈Y=3.69×10~(-3)×1.07~x的指数函数关系,由此得到,17℃—19℃是隆线搔生长速率快而耗氧量较小的最适人工培养温度。