Media-Based Sentiment Indices as an Alternative Measure of Consumer Confidence

In this paper, we consider the feasibility of constructing online sentiment indices, using large amounts of media data, as an alternative to the conventional survey method used to create the consumer confidence index in South Africa. A clustering framework is adopted to provide an indication of possible candidate sentiment indices constructed from a combination of different text sources and dictionaries that best mimic the traditional survey-based consumer confidence index from the South African Bureau for Economic Research (BER). The results conclude that it is possible to create an index using sentiment analysis using online editorial data that does resemble the BER’s consumer confidence index. The different media-based sentiment indices (MSI) show a significant level of correlation and co-movement with the BER’s CCI. Impulse responses and cross-correlation functions indicate that the MSI could potentially lead the survey-based method up to two quarters. Furthermore, Granger-causality tests show that the media-based indices are good predictors of future consumer confidence index values. The results provide motivation for further study on the use of sentiment-based techniques and online media data sources to track consumer confidence within an emerging market such as South Africa.     

土工实验中的液、塑限测定浅议

文章分析了当前土工实验中的液、塑限测定过程中应当注意的问题及其存在的问题,并论述了如何对其实验数据进行处理和分析的方法。     

Probability theory in fuzzy sample spaces

This paper tries to develop a neat and comprehensive probability theory for sample spaces where the events are fuzzy subsets of The investigations are focussed on the discussion how to equip those sample spaces with suitable -algebras and metrics. In the end we can point out a unified concept of random elements in the sample spaces under consideration which is linked with compatible metrics to express random errors. The result is supported by presenting a strong law of large numbers, a central limit theorem and a Glivenko-Cantelli theorem for these kinds of random elements, formulated simultaneously w.r.t. the selected metrics. As a by-product the line of reasoning, which is followed within the paper, enables us to generalize as well as to bring together already known results and concepts from literature.Acknowledgement. The author would like to thank the participants of the 23rd Linz Seminar on Fuzzy Set Theory for the intensive discussion of the paper. Especially he is indebted to Professors Diamond and Höhle whose remarks have helped to get deeper insights into the subject. Additionally, the author is grateful to one anonymous referee for careful reading and valuable proposals which have led to an improvement of the first draft.This paper was presented at the 23rd Linz Seminar on Fuzzy Set Theory, Linz, Austria, February 5–9, 2002.     

实时控制系统中的任务模型及调度算法设计

控制系统的实时任务能否在规定的时限内完成依赖于调度算法的好坏。首先给出控制系统中实时任务模型，包括实时周期任务和实时非周期任务；然后，在考虑优先级倒置和非周期任务的基础上，介绍一种静态优化调度算法(RMS)；最后，对调度算法进行可调度性分析。     

基于自动补货技术开发的便利店门店库存管理模型

本文针对当前我国便利店门店存在库存管理不合理的问题．运用了经典预测技术和数据分析知识，引用了SPSS数据分析软件的P—P概率图．结合当前最新发展的库存管理思想。为门店开发了支持自动补货系统的上下限库存管理模型．从而完善了门店的库存管理系统。     

公路施工企业复合标底投标报价博弈模型的研究

通过对公路工程复合标底投标报价的分析,研究了复合标底的评分办法的博弈规则,建立了基于博弈论的投标报价模型,分析了模型的假设条件及适用范围,并对模型进行了全面评述。     

企业信用管理制度可靠性及有效性探讨

笔者认为企业信用管理经典计算存在严重缺陷,不适合企业应用;本文通过典型案例分析,讨论企业授信制度建设、存在风险以及补救措施;对确定客户信用额度的各种方法进行分析比较并讨论其适用性及有效性。通过分析企业必须面对而又难以把握的企业信用管理核心问题,结合实际、层层深入进行探讨,为企业信用管理决策提供指导意见。     

农民增收的极限约束与跨跃路径

从长期看,农民增收有两个极限性约束条件:一是收入增长速度不能高于或者相当于城市居民收入增长速度;二是农民收入增幅不能高于农村财富的增幅。但是农民收入又不能不维持大幅度的增长,否则会影响国民经济的增长,影响政治社会的稳定。要解决这对矛盾,必须通过农村内部挖潜,拓宽内源性增收空间;调整束缚增收的制度;寻找和扩大外源性增收渠道。     

Chance Constrained Programming Formulations for Stochastic Characterizations of Efficiency and Dominance in DEA

Pareto-Koopmans efficiency in Data Envelopment Analysis (DEA) is extended to stochastic inputs and outputs via probabilistic input-output vector comparisons in a given empirical production (possibility) set. In contrast to other approaches which have used Chance Constrained Programming formulations in DEA, the emphasis here is on joint chance constraints. An assumption of arbitrary but known probability distributions leads to the P-Model of chance constrained programming. A necessary condition for a DMU to be stochastically efficient and a sufficient condition for a DMU to be non-stochastically efficient are provided. Deterministic equivalents using the zero order decision rules of chance constrained programming and multivariate normal distributions take the form of an extended version of the additive model of DEA. Contacts are also maintained with all of the other presently available deterministic DEA models in the form of easily identified extensions which can be used to formalize the treatment of efficiency when stochastic elements are present.     

Asymptotic confidence bands for the estimated autocovariance and autocorrelation functions of vector autoregressive models

This paper provides closed-form formulae for computing the asymptotic covariance matrices of the estimated autocovariance and autocorrelation functions of stable VAR models by means of the delta method. These covariance matrices can be used to construct asymptotic confidence bands for the estimated autocovariance and autocorrelation functions to assess the underlying estimation uncertainty. The usefulness of the formulae for empirical work is illustrated by an application to inflation and output gap data for the U.S. economy indicating the existence of a significant short-run Phillips-curve tradeoff.First version received: November 2002/Final version received: September 2003