浅谈高压变频调速系统特点与应用

本文以对某钢铁企业2×360m2烧结机主抽风机电机高压变频调速系统调试为例,阐述了高压变频速系统的分类、特点和应用。     

On the pricing of real estate index linked swaps

In this paper we discuss the pricing of commercial real estate index linked swaps (CREILS). This particular pricing problem has been studied by Buttimer et al. in a previous paper in this journal (6 [1997]: 16). We show that their results are only approximately correct and that the true theoretical price of the swap is in fact equal to zero. This result is shown to hold regardless of the specific model chosen for the index process, the dividend process, and the interest rate term structure. We provide an intuitive economic argument as well as a full mathematical proof of our results. In particular we show that the nonzero result in the previous paper is due to two specific numerical approximations introduced in that paper, and we discuss these approximation errors from a theoretical as well as from a numerical point of view.     

Dynamics of financial returns densities: A functional approach applied to the Bovespa intraday index

We model the stochastic evolution of the probability density functions (PDFs) of Ibovespa intraday returns over business days, in a functional time series framework. We find evidence that the dynamic structure of the PDFs reduces to a vector process lying in a two-dimensional space. Our main contributions are as follows. First, we provide further insights into the finite-dimensional decomposition of the curve process: it is shown that its evolution can be interpreted as a dynamic dispersion-symmetry shift. Second, we provide an application to realized volatility forecasting, with a forecasting ability that is comparable to those of HAR realized volatility models in the model confidence set framework.     

城市化率指标的本质与合理目标进度问题

针对当前我国地方政府制定高城市化率目标提出质疑,分析和讨论了这一现象的根源和本质,并指出地方政府不应盲目攀比,而须根据自身基础和发展条件,制定合理的、合适的城市化率目标.     

城市水安全评价指标体系研究

在对国内外水安全相关指标体系归纳总结和评述的基础上,分析了城市水安全评价指标体系建立的指导思想、设计原则、构建方法,据此将城市水安全这一复杂巨系统分为支持子系统、协调子系统、发展子系统,通过构建7个状态层和16个具体指标,建立了系统完整、逻辑清晰、层次结构分明的城市水安全评价指标体系。     

变频调速技术在风机实验台中的应用

风机实验台是风机性能测试的重要实验设备。针对电磁调速电机存在的问题,本研究基于变频调速方法提出一种由转速传感器、变频器及单片机等组成的闭环速度控制系统。     

Generalized confidence intervals for the process capability index C pm

Process capability indices have been proposed to the manufacturing industry for measuring process reproduction capability. The C _pm index takes into account the degree of process targeting (centering), which essentially measures process performance based on average process loss. To properly and accurately estimate the capability index, numerous conventional approaches have been proposed to obtain lower limits of the classical confidence intervals (CLCLs) for providing process capability information. In particular, lower confidence limits (LCLs) not only provide critical information regarding process performance but are used to determine if an improvement was made in reducing the nonconforming percent and the process expected loss. However, the conventional approach lacks for exact confidence intervals for C _pm involving unknown parameters which is a notable shortcoming. To remedy this, the method of generalized confidence intervals (GCIs) is proposed as an extension of classical confidence intervals (CCIs). For evaluating practical applications, two lower limits of generalized confidence intervals (GLCLs) for C _pm using generalized pivotal quantities (GPQs) are considered, (i) to assess the minimum performance of one manufacturing process/one supplier, and (ii) to assess the smallest performance of several manufacturing processes/several suppliers for equal as well as unequal process variances.     

Developing and implementing an environmental performance index for the Portuguese military

At an international level, the implementation of environmental management practices in military facilities is now a growing reality, particularly with the implementation of environmental management programmes and/or systems. The main goal of this research was to assess the Portuguese military sector's environmental performance through an index – the MEPE index – in a simplified and useful manner. A second goal was to measure the units' self‐assessment against the environmental profile of the military sector as evaluated through the index, to determine how far they match. The index was deeloped on the basis of the data obtained in a national questionnaire, which was carried out to evaluate environmental practices adopted by military units. Results show that the Portuguese military's overall environmental performance is poor, reflecting that this is quite a new issue in military organizations. Among the military branches the Air Force reveals the best environmental results. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.     

Position limit for the CSI 300 stock index futures market

The aim of this study was to find the optimal position limit for the Chinese stock index (CSI) 300 futures market. A low position limit helps to prevent price manipulations in the spot market, and thus keeps the magnitude of instantaneous price changes within the tolerance range of policymakers. However, setting a position limit that is too low may also have negative effects on market quality. We propose an artificial limit order market with heterogeneous interacting agents to examine the impact of different levels of position limits on market quality, measured as liquidity, return volatility, efficiency of information dissemination, and trading welfare. The simulation model is based on realistic trading mechanisms, investor structure, and order submission behavior observed in the CSI 300 futures market.Our results show that on the basis of the liquidity status in September 2010, raising the position limit from 100 to 300 could significantly improve market quality and at the same time keep the maximum absolute price change per 5 s below the 2% tolerance level. However, the improvement becomes only marginal if the position limit is further increased beyond 300. Therefore, we believe that raising the position limit to a moderate level can enhance the functionality of the CSI 300 futures market, which should benefit the development of the Chinese financial system.     

城市地下空间开发利用容量评估指标体系的研究

地下空间是城市开发的重要自然资源,城市地下空间开发利用容量评估的目的旨在把握城市所具有的地下空间可开发利用的总量和潜力,建立科学的评估指标体系是地下空间开发利用容量评估的基础.本文分析了城市地下空间开发利用容量的主要影响因素,提出了城市地下空间开发利用容量评估指标体系构建的原则.基于层次分析法建立了城市地下空间开发利用容量评估的层次结构模型,依据该层次结构模型构造了各层次判断矩阵,并进行了层次单排序、层次总排序及其一致性检验.经研究分析得到:地面空间类型、受已开发地下空间的影响程度、地震烈度、滑坡及崩塌、对工程有影响的地下水层数、受影响的地下水赋存类型及活断层等是城市地下空间开发利用容量评估的主要指标.     

The construction of a composite index for general satisfaction in Turkey and the investigation of its determinants

The goal of public enterprises is to increase the wealth and happiness of individuals. This target lets them make the investment to fulfill these expectations. However, not all citizens in a country might have the same opportunities. This case requires comparing citizens who live in cities with regard to satisfaction levels. This study consists of two stages. In the first stage, a composite index called the General Satisfaction Index (GSI), which aims to explain the satisfaction levels of citizens living in cities, is obtained by using the Benefit of the Doubt method. Contrary to the previous studies, the satisfaction indicators based on the emotions and senses of citizens are used to construct a composite index. Satisfaction indicators’ contribution to GSI is ensured using the minimum weights. In the second stage of this study, socioeconomic determinants of GSI are investigated in both countrywide and regions by using regularized regression methods. In the result of the regression analyze, it is confirmed that there are different socioeconomic determinants of satisfaction levels for countrywide and each region. For this reason, it is proposed that policymakers should follow different politicizes in each region to increase the satisfaction levels of citizens in the country.     

储层渗透率变异系数算法研究——以茨榆坨采油厂牛74块为例

茨榆坨采油厂牛74块沙二段储层物性较差,层内非均质性较强。为了研究储层层内非均质性,常用层内渗透率变异系数、突进系数、级差来定量表征储层层内非均质强弱程度。然而利用传统的地质统计学的方法计算出的渗透率变异系数范围在0~+∞之间,很难从定量的建立层内非均质程度的概念。针对此问题,本文利用与数据分布类型无关的洛伦兹曲线法建立层内渗透率变异系数模型,它求出的范围在0~1之间,可比性、适应性强,能明确反应层内非均质强弱程度。劳伦兹曲线法更适用于储层非均质性定量评价。