浅谈民用建筑变配电系统的设计与发展

变配电系统是变电系统和配电系统的总称,变配电系统在民用建筑中起到至关重要的作用。文章介绍了变配电系统的设计发展历程、现状、发展趋势,提出了民用建筑变配电系统方案,并对方案进行了探讨。     

On distribution-free goodness-of-fit testing of exponentiality

There is a need to test the hypothesis of exponentiality against a wide variety of alternative hypotheses, across many areas of economics and finance. Local or contiguous alternatives are the closest alternatives against which it is still possible to have some power. Hence goodness-of-fit tests should have some power against all, or a huge majority, of local alternatives. Such tests are often based on nonlinear statistics, with a complicated asymptotic null distribution. Thus a second desirable property of a goodness-of-fit test is that its statistic will be asymptotically distribution free. We suggest a whole class of goodness-of-fit tests with both of these properties, by constructing a new version of empirical process that weakly converges to a standard Brownian motion under the hypothesis of exponentiality. All statistics based on this process will asymptotically behave as statistics from a standard Brownian motion and so will be asymptotically distribution free. We show the form of transformation is especially simple in the case of exponentiality. Surprisingly there are only two asymptotically distribution free versions of empirical process for this problem, and only this one has a convenient limit distribution. Many tests of exponentiality have been suggested based on asymptotically linear functionals from the empirical process. We illustrate none of these can be used as goodness-of-fit tests, contrary to some previous recommendations. Of considerable interest is that a selection of well-known statistics all lead to the same test asymptotically, with negligible asymptotic power against a great majority of local alternatives. Finally, we present an extension of our approach that solves the problem of multiple testing, both for exponentiality and for other, more general hypotheses.     

A Measure of Representativeness of a Sample for Inferential Purposes

After defining the concept of representativeness of a random sample, the author proposes a measure of how much the observed sample represents its parent distribution. This measure is called Representativeness Index. The same measure, seen as a function of a sample and of a distribution, will be called Representativeness Function. For a given sample it provides the value of the index for the different distributions under examination, and for a given distribution it provides a measure of the representativeness of its possible samples. Such Representativeness Function can be used in an inferential framework just as the likelihood function, since it gives to any distribution the "experimental support" provided by the observed sample. This measure is distribution-free and it is shown to be a transformation of the wellknown Cramér–von Mises statistic. By using the properties of that statistic, criteria for providing set estimators and tests of hypotheses are introduced. The utilization of the representativeness function in many standard statistical problems is outlined through examples. The quality of the inferential decisions can be assessed with the usual techniques (MSE, power function, coverage probabilities). The most interesting examples turn out to be those of situations that are "non-regular", as for instance the estimation of parameters involved in the support of the parent distribution, or less explored (model choice).     

试论智能电网的配电自动化改造

在电网快速发展的当下,进行智能电网的配电自动化改造已经成为大势所趋,它不仅有力的推动着电力事业的发展,对于提高电网运行效率而言也具有重要意义。本文针对智能电网中的配电自动化改造进行研究,首先对相应系统的结构和技术指标进行了阐述,对智能电网配电自动化的发展进行了综述,分析了智能电网与配电自动化之间的关系,重点对改造进行了研究,包括:主站改造、子站改造以及终端改造,最后对改造效率进行了分析。     

浅谈变电所的常见故障处理

变电所是电力系统中通过其变换电压、接受和分配电能的电工装置,它是联系发电厂和电力用户的中间环节,同时通过变电所将各电压等级的电网联系起来,变电所的作用是变换电压,传输和分配电能。     

A weighted Kuiper statistic for goodness of fit

A variance-weighted Kuiper statistic for goodness of fit is studied. The exact finite sample distribution can be obtained through modification of Noé's (1972) algorithm. Asymptotic distribution theory for the statistic is available from Jaeschke (1979) and Eicker (1979), but this theory does not lead to useful approximations with finite sample sizes less than 100. Monte Carlo power studies demonstrate that the weighted Kuiper statistic is especially sensitive to alternatives that are not stochastically ordered relative to the postulated null distribution.     

Could lean practices and process innovation enhance supply chain sustainability of small and medium‐sized enterprises?

Small and medium‐sized enterprises (SMEs) adopt lean practices (LP) to reduce waste across their organisational value chain, which helps achieve sustainability. Process innovation (PI) has also been applied through cleaner production, environmental management system, ecodesign, and so on to address both customers' needs and legislations by policymakers. Although prior studies reveal the effect of sustainable practices, LP, and PI on sustainable performance separately, less is known on the integrated effect of them on sustainability performance. Moreover, studies on mediating effect of LP and PI on sustainability performance are scant. This is significant as LP and PI are considered to be the enablers for achieving sustainability performance. This research addresses this knowledge gap. The research first theorises a model integrating these four major constructs (sustainability practices, LP, PI, and sustainability performance) through hypotheses development. Subsequently, using structural equation modelling, it is tested whether each of sustainability practices, LP, and PI effect sustainability performances. Additionally, mediating effect of LP and PI between sustainability practices and performances is derived. The study uses data from 119 SMEs within manufacturing industries in the Midlands, United Kingdom. Further, a few case studies have been undertaken to validate the findings from quantitative analysis. The overall results show that although sustainability practices, LP, and PI help achieve sustainability performance of SMEs supply chain through efficiency and responsiveness respectively, the mediating effect LP is more compared with PI. Moreover, SMEs adopt LP when they are economy focused and implement PI when they are pressurised by customers and/or policymakers.     

基于模糊优选模型的输变电工程造价管理成效评价研究

输变电工程造价管理对于电网投资效益具有重要的意义.目前对输变电工程造价管理工作成效的评价往往依靠主观判断,缺乏一种客观、准确的评价方法,为此,本文针对输变电工程造价管理成效开展评价研究.首先运用德尔菲法、层次分析法分析输变电工程造价管理的影响因素,建立综合评价指标;其次,基于模糊优选模型建立造价管理成效评价模型;最后,...     

智能紧凑型高压开关设备设计探讨

随着国民经济的快速发展,供电的质量以及电器设备的一些性能对于城镇化建的重要性也有了提高。同时,我国城乡电网建设和改造工程要求供配电向节约土地、节电、紧凑型、小型化、无人值守的方向发展,因此不仅要求作为供电电源的高压开关设备安全可靠,同时也应具有智能化功能和体积紧凑小型化。     

A robust Hotelling test

Hotelling's T ² statistic is an important tool for inference about the center of a multivariate normal population. However, hypothesis tests and confidence intervals based on this statistic can be adversely affected by outliers. Therefore, we construct an alternative inference technique based on a statistic which uses the highly robust MCD estimator [9] instead of the classical mean and covariance matrix. Recently, a fast algorithm was constructed to compute the MCD [10]. In our test statistic we use the reweighted MCD, which has a higher efficiency. The distribution of this new statistic differs from the classical one. Therefore, the key problem is to find a good approximation for this distribution. Similarly to the classical T ² distribution, we obtain a multiple of a certain F-distribution. A Monte Carlo study shows that this distribution is an accurate approximation of the true distribution. Finally, the power and the robustness of the one-sample test based on our robust T ² are investigated through simulation.     

潍坊公司#2机组凝汽器改造项目后评估

本文从华电潍坊发电公司#2机组改造项目出发,介绍了项目实施的背景及意义、项目进行中的管理措施,结合项目实际进行了投资收益估算,通过实际运行检验证明项目改造是成功的,最后总结提出了项目对于其他老电厂的技术改造具有借鉴意义。     

Testing Stationarity in Small‐ and Medium‐Sized Samples when Disturbances are Serially Correlated*

In this article, we study the size distortions of the KPSS test for stationarity when serial correlation is present and samples are small‐ and medium‐sized. It is argued that two distinct sources of the size distortions can be identified. The first source is the finite‐sample distribution of the long‐run variance estimator used in the KPSS test, while the second source of the size distortions is the serial correlation not captured by the long‐run variance estimator because of a too narrow choice of truncation lag parameter. When the relative importance of the two sources is studied, it is found that the size of the KPSS test can be reasonably well controlled if the finite‐sample distribution of the KPSS test statistic, conditional on the time‐series dimension and the truncation lag parameter, is used. Hence, finite‐sample critical values, which can be applied to reduce the size distortions of the KPSS test, are supplied. When the power of the test is studied, it is found that the price paid for the increased size control is a lower raw power against a non‐stationary alternative hypothesis.     

Stability results for nonlinear error correction models

This paper studies analogs of Granger's representation theorem in the context of a general nonlinear vector autoregressive error correction model. The model allows for nonlinear autoregressive conditional heteroskedasticity and the conditional distribution involved can be a mixture distribution of a rather general type. Mixture models of this kind can be thought of as generalizations of threshold models and they have attracted attention in the recent time series and econometrics literature. The paper develops a useful transformation which shows how the nonlinear error correction model can be transformed to a nonlinear vector autoregressive model so that available results on the stationarity or nonstationarity of the latter can be used for the former. The most satisfactory results are obtained in a model in which a specific structural relation between the nonlinearity and equilibrium correction prevails. Without this structural relation only a lower bound for the number of long-run equilibrium relations can explicitly be determined because the exact number depends on properties of the first and second moments of a nonlinear stationary component of the process.     

关于锅炉点火稳燃技术的讨论

锅炉最低负荷主要取决于燃烧稳定性。根据国家能源局对火电灵活性改造的要求及集团公司的相关要求,实施灵活性改造后,机组深度调峰能力需达到30%负荷以下,原则上要达到25%负荷。论文主要是保证该电厂1号锅炉在冷炉点火时不投或少投大油枪,节约大量燃油,在最低稳燃负荷(130MW)以下助燃时保证锅炉稳定燃烧,且不对尾部脱硝、空预器、电除尘及脱硫等系统造成不利影响。     

劳动力成本上升会倒逼制造业企业服务化转型吗?——异质性讨论与动机识别

本文基于2009—2019年中国A股制造业上市公司数据,测算了制造业企业服务化水平,实证分析发现:劳动力成本上升显著促进了制造业企业服务化转型。异质性讨论表明:高生产率、低融资约束和规模较大的制造业企业在应对劳动力成本上升时,服务化转型的意愿更大。动机识别检验表明:劳动力成本上升会弱化制造业企业市场势力,服务化转型对企业市场势力具有重塑效应;服务化与技术创新均是制造业企业应对劳动力成本上升的转型路径,二者间存在替代性。最后提出政策启示:促进人力资本深化,驱动劳动力数量优势向质量优势转型,是弥补劳动力成本上升短板的关键;利用新技术形态创造的新契机,是助力服务化转型迈向高级化和现代化的重要机遇;同时,应谨防制造业企业服务化转型过程中虚拟化和空心化趋势。     

Random Effects Misspecification Can Have Severe Consequences for Random Effects Inference in Linear Mixed Models

There has been considerable and controversial research over the past two decades into how successfully random effects misspecification in mixed models (i.e. assuming normality for the random effects when the true distribution is non‐normal) can be diagnosed and what its impacts are on estimation and inference. However, much of this research has focused on fixed effects inference in generalised linear mixed models. In this article, motivated by the increasing number of applications of mixed models where interest is on the variance components, we study the effects of random effects misspecification on random effects inference in linear mixed models, for which there is considerably less literature. Our findings are surprising and contrary to general belief: for point estimation, maximum likelihood estimation of the variance components under misspecification is consistent, although in finite samples, both the bias and mean squared error can be substantial. For inference, we show through theory and simulation that under misspecification, standard likelihood ratio tests of truly non‐zero variance components can suffer from severely inflated type I errors, and confidence intervals for the variance components can exhibit considerable under coverage. Furthermore, neither of these problems vanish asymptotically with increasing the number of clusters or cluster size. These results have major implications for random effects inference, especially if the true random effects distribution is heavier tailed than the normal. Fortunately, simple graphical and goodness‐of‐fit measures of the random effects predictions appear to have reasonable power at detecting misspecification. We apply linear mixed models to a survey of more than 4 000 high school students within 100 schools and analyse how mathematics achievement scores vary with student attributes and across different schools. The application demonstrates the sensitivity of mixed model inference to the true but unknown random effects distribution.     

A consistent nonparametric test for nonlinear causality—Specification in time series regression

Since the pioneering work by Granger (1969), many authors have proposed tests of causality between economic time series. Most of them are concerned only with “linear causality in mean”, or if a series linearly affects the (conditional) mean of the other series. It is no doubt of primary interest, but dependence between series may be nonlinear, and/or not only through the conditional mean. Indeed conditional heteroskedastic models are widely studied recently. The purpose of this paper is to propose a nonparametric test for possibly nonlinear causality. Taking into account that dependence in higher order moments are becoming an important issue especially in financial time series, we also consider a test for causality up to the Kth conditional moment. Statistically, we can also view this test as a nonparametric omitted variable test in time series regression. A desirable property of the test is that it has nontrivial power against T^1/2-local alternatives, where T is the sample size. Also, we can form a test statistic accordingly if we have some knowledge on the alternative hypothesis. Furthermore, we show that the test statistic includes most of the omitted variable test statistics as special cases asymptotically. The null asymptotic distribution is not normal, but we can easily calculate the critical regions by simulation. Monte Carlo experiments show that the proposed test has good size and power properties.     

Episodic and Systemic Power in the Transformation of Professional Service Firms

We examine the roles of episodic and systemic forms of power in radical organizational change. Drawing on a study of three attempted transformations in professional service firms from traditional professional partnerships into managed professional businesses – one relatively complete and two incomplete – we identify two key mechanisms that link episodic and systemic forms of power and show how those mechanisms affect the likelihood that organizations will be able to successfully undergo radical change. We find that episodic power is able to initiate and energize radical change when it represents a significant break from traditional authority structures and is legitimated through appeals to traditional organizational values. We find that systemic power is able to institutionalize radical change when the systems associated with it are legitimated by the skilled use of language by key actors and then left to operate independently by those actors. By articulating the specific mechanisms that link episodic and systemic power, our study provides a more complete model of the role of power in radical change, enabling better prediction of the likelihood of successful transformation and a fuller theoretical explanation of change outcomes.     

Is Leadership in Creativity and Innovative Technology the Cure for Quality Affordable Healthcare?

Disruptive innovation is necessary in healthcare if we are to solve America's healthcare crisis. Patients need access to high quality, convenient, cost‐effective healthcare. Industry leadership and the government together need to facilitate the transformation of the healthcare industry through innovative multidisciplinary models that will improve health outcomes, decrease costs, and improve access to care. Such a transformation can be realized by embracing the concept of precision medicine, where outcomes are managed and government facilities advancements through effective regulation.     

Urbanization as A Process of State Building: Local Governance Reforms in China

Existing scholarship suggests that local transformation in reform‐era China has been a process of decentralization of state power driving extractive local governments to pursue economic growth through rapacious land appropriation and producing many miserable landless villagers. This study puts forward an alternative perspective by arguing that local governance reforms in China to advance urban development should also be interpreted as a process of state building, whereby local government reshaped its governance strategy so as to mitigate potential social unrest and strengthen its political legitimacy in governing rapidly urbanizing areas. Based on intensive fieldwork in a periurban district in southern China, this research examines how the local state has heightened its control over urbanizing villages through its day‐to‐day governance practices and the pursuit of a complex policy agenda comprising social welfare provision, shareholding reforms and intervention in grassroots politics. The findings of this study shed new light on understanding local state transformation in periurban China and on explaining why the country still maintains tremendous urban growth despite incessant land disputes and numerous social tensions at different localities.