Construction of Health Indices Using Paired Comparisons

The paper discusses, by making use of past experiences in the area, the main issues and the methodology of developing a health status instrument for a developing country from a well-established instrument. The use of Thurstone's model of paired comparisons in evaluating the relative importance of health symptoms has been reviewed and some alternative models, i.e., Linear, Exponential, and Information, are proposed. By applying the models to the health data of Chinese elderly persons, the three models have been demonstrated to be able to produce some valid and responsive health scores.     

Multidimensional scaling models with inequality and equality constraints

Recently, a lot of attention has been brought to constrained estimation theory in multidimensional scaling models. So far, only equality constraints have been thoroughly studied. In this paper, the optimization theory is extended to general multidi-mensional scaling models with both inequality and equality constraints. A Newton-Raphson based algorithm is developed to produce the constrained least squares estimate. To illustrate the theory, some classical color data are reanalyzed in the context of the linear Euclidean distance model.     

淖尔油田阻垢剂评价实验研究

淖尔油田的结垢问题严重影响了油田的正常生产，针对该油田结垢严重的实际情况，开展了防垢实验研究。实验考查了目前常用的阻垢剂A、阻垢剂HYZ、南京1、南京2、南京3和JL661这几种阻垢剂的阻垢性能，并将阻垢剂A与阻垢剂HYZ进行复配，按1∶1复配时其阻垢效果最佳。研究了该复配阻垢剂对淖尔油田部分油水井产出液的阻垢效果，实验结果表明：该复配阻垢剂的加量合适时对钙、镁的阻垢率可达96.00%以上，对钡、锶的阻垢率可达90.00%以上。     

A Psychometric Study of Information Technology Risks in the Workplace

As organizations become increasingly reliant on information technology (IT) they are exposed to a growing number of risks. Surprisingly, however, very few studies to date have investigated the psychometric representation of IT risks, and none have been undertaken in the workplace. Accordingly, the present study was designed to map the judgments of a representative group of workplace IT users. Fifty-seven participants evaluated 18 IT risk scenarios by means of 13 bipolar attribute-rating scales. Profile proximities derived from the raw data were submitted to a weighted multidimensional scaling analysis. The results indicated that a six-dimensional solution was required on both statistical and conceptual grounds to represent adequately the participants' judgments. The dimensions reflected the extent to which the various risk scenarios were perceived as: (1) serious or minor in nature; (2) having a high or low probability of occurrence; (3) causing a high or low degree of stress; (4) deliberate or accidental; (5) having an impact on the organization or on individuals; and (6) the product of human or technological causes. The data were also submitted to a series of hierarchical cluster analyses, using a variety of agglomeration techniques. This second approach revealed a robust structure in which the risk scenarios were grouped into two broad categories, based on whether the events depicted would be likely to have a major or minor impact. The major impact category broke down further, into two subcategories, based on whether the scenarios were seen to arise from deliberate causes or through negligence. In conclusion, we consider the implications of our findings for future research, the refinement of IT risk assessment frameworks and tools, and the training of risk management professionals.     

Statistical Inference in Context Specific Interaction Models for Contingency Tables

Abstract.  Context specific interaction models is a class of interaction models for contingency tables in which interaction terms are allowed to vanish in specific contexts given by the levels of sets of variables. Such restrictions can entail conditional independencies which only hold for some values of the conditioning variables and allows also for irrelevance of some variables in specific contexts. A Markov property is established and so is an iterative proportional scaling algorithm for maximum likelihood estimation. Decomposition of the estimation problem is treated and model selection is discussed.     

EXAMPLES OF MINIMUM VARIANCE ESTIMATION1

In this sequel to a previous discussion of minimum variance estimation (Bartlett, 1982), the gain with conditional estimation procedures is illustrated for the location parameter for (i) the rectangular distribution; (ii) a triangular distribution (typifying an asymmetric case). This note concludes with further remarks on the multi-sample and multi-parameter cases.     

家庭农场优势与农地规模化的路径选择

家庭农场式的规模经营有助于提升农业生产效率,易于制定、执行较为严密的年度生产经营计划,易于发挥农民的勤劳本色。对西方发达国家及东亚国家和地区的农地规模化经验及我国的实际情况的分析表明．家庭农场经营是我国农地规模化的正确选择。     

框式凸规划的原—对偶仿射尺度算法

文章对框式凸规划问题设计了一个原—对偶仿射尺度算法 ,证明该算法的迭代复杂性为多项式时间性     

Power-law scaling behavior analysis of financial time series model by voter interacting dynamic system

We investigate the power-law scaling behaviors of returns for a financial price process which is developed by the voter interacting dynamic system in comparison with the real financial market index (Shanghai Composite Index). The voter system is a continuous time Markov process, which originally represents a voter's attitude on a particular topic, that is, voters reconsider their opinions at times distributed according to independent exponential random variables. In this paper, the detrended fluctuation analysis method is employed to explore the long range power-law correlations of return time series for different values of parameters in the financial model. The findings show no indication or very weak long-range power-law correlations for the simulated returns but strong long-range dependence for the absolute returns. The multiplier distribution is studied to demonstrate directly the existence of scale invariance in the actual data of the Shanghai Stock Exchange and the simulation data of the model by comparison. Moreover, the Zipf analysis is applied to investigate the statistical behaviors of frequency functions and the distributions of the returns. By a comparative study, the simulation data for our constructed price model exhibits very similar behaviors to the real stock index, this indicates somewhat rationality of our model to the market application.     

A Comparison of Different Methods for Representing Categorical Data

We first compare correspondence analysis, which uses chi-square distance, and an alternative approach using Hellinger distance, for representing categorical data in a contingency table. We propose a coefficient which globally measures the similarity between these two approaches. This coefficient can be decomposed into several components, one component for each principal dimension, indicating the contribution of the dimensions to the difference between the two representations. We also make comparisons with the logratio approach based on compositional data. These three methods of representation can produce quite similar results. Two illustrative examples are given.