Determination of anaerobic threshold

This report describes the estimation of the parameters for a model of ventilation (y) by human subjects as a two-segment linear function of oxygen uptake (x). Experimental data were supplied by R.L. Hughson of the Department of Kinesiology. The analysis of one of nine available sets of data is described in detail.     

Selection of the Transformation Variable in the Laplace Transform Method of Estimation

The work of this paper is based on the innovative approach of Feigin et al. (1983), who estimate parameters of lifetime distributions by equating empirical and theoretical Laplace transforms. We show that the optimal choice of the transform variable depends critically upon the number of sampling times, the way they are spaced, and how the empirical transform is formed. Two new approaches for choosing the transform variable, viz. using cross-validation or constrained optimisation, are introduced and shown to have potential for wide-ranging use.     

On maximum likelihood estimation of the semi-parametric Cox model with time-varying covariates

Including time-varying covariates is a popular extension to the Cox model and a suitable approach for dealing with non-proportional hazards. However, partial likelihood (PL) estimation of this model has three shortcomings: (i) estimated regression coefficients can be less accurate in small samples with heavy censoring; (ii) the baseline hazard is not directly estimated and (iii) a covariance matrix for both the regression coefficients and the baseline hazard is not easily produced.We address these by developing a maximum likelihood (ML) approach to jointly estimate regression coefficients and baseline hazard using a constrained optimisation ensuring the latter''s non-negativity. We demonstrate asymptotic properties of these estimates and show via simulation their increased accuracy compared to PL estimates in small samples and show our method produces smoother baseline hazard estimates than the Breslow estimator.Finally, we apply our method to two examples, including an important real-world financial example to estimate time to default for retail home loans. We demonstrate using our ML estimate for the baseline hazard can give much clearer corroboratory evidence of the ‘humped hazard’, whereby the risk of loan default rises to a peak and then later falls.     

Constructing optimal designs for fitting pharmacokinetic models

We consider some computational issues that arise when searching for optimal designs for pharmacokinetic (PK) studies. Special factors that distinguish these are (i) repeated observations are taken from each subject and the observations are usually described by a nonlinear mixed model (NLMM), (ii) design criteria depend on the model fitting procedure, (iii) in addition to providing efficient parameter estimates, the design must also permit model checking, (iv) in practice there are several design constraints, (v) the design criteria are computationally expensive to evaluate and often numerical integration is needed and finally (vi) local optimisation procedures may fail to converge or get trapped at local optima.We review current optimal design algorithms and explore the possibility of using global optimisation procedures. We use these latter procedures to find some optimal designs.For multi-purpose designs we suggest two surrogate design criteria for model checking and illustrate their use.     

Replenishing the pipeline: A quantitative approach to optimising the sourcing of new projects

Large pharmaceutical companies maintain a portfolio of assets, some of which are projects under development while others are on the market and generating revenue. The budget allocated to R&D may not always be sufficient to fund all the available projects for development. Much attention has been paid to the selection of optimal subsets of available projects to fit within the available budget. In this paper, we argue the need for a forward-looking approach to portfolio decision-making. We develop a quantitative model that allows the portfolio management to evaluate the need for future inflow of new projects to achieve revenue at desired levels, often aspiring to a certain annual revenue growth. Optimisation methods are developed for the presented model, allowing an optimal choice of number, timing and type of projects to be added to the portfolio. The proposed methodology allows for a proactive approach to portfolio management, prioritisation, and optimisation. It provides a quantitatively based support for strategic decisions regarding the efforts needed to secure the future development pipeline and revenue stream of the company.     

Optimal acceptance sampling for modules F and F1 of the European Measuring Instruments Directive

ABSTRACT

Acceptance sampling plans offered by ISO 2859-1 are far from optimal under the conditions for statistical verification in modules F and F1 as prescribed by Annex II of the Measuring Instruments Directive (MID) 2014/32/EU, resulting in sample sizes that are larger than necessary. An optimised single-sampling scheme is derived, both for large lots using the binomial distribution and for finite-sized lots using the exact hypergeometric distribution, resulting in smaller sample sizes that are economically more efficient while offering the full statistical protection required by the MID.     

Sequential experimental design and response optimisation

We consider the situation where one wants to maximise a functionf(θ,x) with respect tox, with θ unknown and estimated from observationsy _k . This may correspond to the case of a regression model, where one observesy _k =f(θ,x _k )+ε _k , with ε _k some random error, or to the Bernoulli case wherey _k ∈{0, 1}, with Pr[y _k =1|θ,x _k |=f(θ,x _k ). Special attention is given to sequences given by , with an estimated value of θ obtained from (x₁, y₁),...,(x _k ,y _k ) andd _k (x) a penalty for poor estimation. Approximately optimal rules are suggested in the linear regression case with a finite horizon, where one wants to maximize ∑ _i=1 ^N w _i f(θ, x _i ) with {w _i } a weighting sequence. Various examples are presented, with a comparison with a Polya urn design and an up-and-down method for a binary response problem.     

能耗指标的投入占用产出研究

能源是人类社会赖以生存和发展的物质基础。能源消耗指标成为当今社会经济工作的约束指标。本文利用投入占用产出技术分别提出了生产、生活以及进出口贸易领域的能耗指标,即：生产综合能耗指标,人均生活综合能耗指标和进出口完全能耗综合指标,并且利用能源投入占用产出表进行了模型分析。实证分析表明,新的能耗指标在国内外生产生活和进出口贸易领域的能源问题上具有很强的可比性和可操作性。     

乡镇统计工作机制有效运转的思考

 乡镇统计是统计工作的重要基础,同时也是目前统计工作的薄弱环节。巩固和加强乡镇统计工作,推动乡镇统计基础工作规范化建设,促进乡镇统计工作机制有效运转,本文提出了具体的设想和思考。本文重点从乡镇统计站建设、人员建设、制度建设三个方面,对乡镇统计工作机制有效发挥作用进行研究,目的在于推进乡镇统计工作机制产生有效生产力。     

利润最大化区位理论与广州高房价的根源

本文利用利润最大化区位理论,建立房价模型,实证研究广州房价持续上涨的根源。发现影响房价的主要因素是住房供给的短缺,次要原因是高成本以及严重的贫富分化。其体制根源在于自由竞争的地产需求市场与计划经济的地产供给市场之间的矛盾,政策根源在于政府变为“经济人”,一味经营城市,经济根源在于因竞争和权力垄断所导致的产业分化,社会根源在于广州市民不合理的住房消费习惯。因而,近期来讲,加大土地供给、改革土地出让方式、实行房地产累进累退税是抑制房价的关键,从长远来讲,要建立自由竞争的地产供给市场,变“经济人”政府为服务性政府,优化产业结构,取消“国字头”行业特权。     

公交车辆在中途站点的排队论分析

公交站台停靠区的排队问题决定了公交车辆的通行能力。把公交中途站台与公交车辆模拟成一个单服务系统、公车到达率 ,两服务率 、 的负指数分布的排队M/M/1/N系统。根据排队论理论,实测计算了北京中关村海淀黄庄、人民大学站点公交车辆排队队长,站内逗留时间等参数。结论为：城市主干道关键站台改造为主、副双公交站台制式以及调整公交线路布设,优化各线路发车频率是花费成本低,畅通成效大的解决站点塞车排队的方法。     

QUALITY CONTROL METHODS IN LARGE-SCALE ASSESSMENT PROCEDURES USING 'DOUBLE-MARKING' OR 'PARTIAL DOUBLE-MARKING'

Ensuring a standard of assessment in situations where marking panels are used is fraught with difficulties, particularly where essay-type responses are to be marked. This paper discusses statistical process control procedures, similar to those used in industry, to help moderate marking quality when ‘double-marking’ or ‘partial double-marking’ are used. When questions are assessed by the same two markers, the scores assigned to responses by each marker may be adjusted so that their assessments are on average equal in terms of location and scale. The paper also discusses methods of controlling sequential assessment, and demonstrates the application of these techniques in evaluating marker consistency, using data from school leaving examinations in geography.     

我国CPI波动的长期驱动力与短期驱动力 ——基于CPI分类指数的分析

 本文根据2001年1月至2008年4月我国CPI篮子的8类居民消费价格分类指数的月度数据,分析了我国CPI波动的特征,并运用Gonzalo和Granger(1995)以及Darrat和Zhong(2002)提出的检验协整系统中的长期驱动力和短期驱动力的方法,从CPI分类指数的角度实证分析了我国CPI波动的长期和短期的决定因素。研究结果显示我国CPI波动的具有明显的结构性,食品、烟酒及用品、交通和通信、娱乐教育文化用品及服务等5类分类指数价格的变动是我国CPI波动的长期驱动力,而食品、衣着、医疗保健及个人用品等5类分类指数价格的变动是短期驱动力。     

森林总经济价值核算研究

森林总经济价值,又称森林的经济效益。人们关注森林对人类的影响,还仅仅是最近几十年的事,而进行测度森林效益的尝试,更只是最近若干年的事。直到现在,这种尝试都还很幼稚,很不完善。战胜了１９９８年特大洪灾之后的中国,人们对洪灾的教训及成因进行了深刻反思。作...     

人民币内向均衡实际汇率与错位测算：1997-2007

 本文基于行为均衡汇率(BEER)理论,运用边限协整检验方法,测算了1997年1月—2007年12月期间人民币内向实际汇率均衡水平和错位程度。实证结果表明：人民币内向实际汇率在大部分时间里错位,不过总体而言错位并不严重。     

中国制造业企业创新行为的观测和实证研究 ——基于浙江省制造业1454家企业问卷调查的分析

 本文在浙江省制造业1454家企业大样本调查问卷的基础上,在微观层面研究了企业创新行为以及影响因素。首先利用统计分析的方法考察了企业创新投入的特征、创新投入的行业分布以及创新投入的产出绩效,并且发现了企业规模与R&;D强度之间呈现倒U型关系,这与安同良等人发现的倾斜V型关系的结论不同。其次运用计量分析的方法在有效控制了企业所处行业的技术水平差异、企业产权结构、政府资金扶持、企业品牌和企业设备技术水平后,研究发现：企业规模与企业创新投入之间也呈现较明显的倒U型关系,并且存在规模“拐点”;企业知识产权战略对企业创新投入具有明显的促进作用;出口贸易对企业创新投入并不显著,但发达国家特别是针对发展中国家设置的技术性贸易壁垒的技术标准化要求对企业创新投入有比较明显的促进作用;而企业集聚对企业的创新投入的影响并不确定。     

简明统计学术史纲要

 本文首先探讨了统计学术史研究的时间范畴;其次将统计学术史划分为四个不同发展阶段：萌芽中的统计学（1654—1750）、推断统计的兴起（1750—1827）、统计学应用领域的拓展及在遗传学领域的突破（1827—1907）、现代统计学理论的建立（1907—1935）;最后本文给出了统计学术史大纲。     

中国与日本分行业TFP水平的国际比较: 1995-2006

 本研究利用以价格表示的国家间分行业全要素生产率（TFP）水平差距的测算模型,测算了1995-2006年中国与日本的TFP水平差距,研究结果表明：中日两国的TFP水平差距在1995年后逐步加大,中国的TFP表现出“没有追赶的快速增长”。