On a model for reciprocity failure in photographic materials

The photographic emulsion is not a pure energy detector. For either very high or very low intensities of the incident light, the efficiency of an emulsion in terms of resulting photographic density is not as great as intermediate levels of intensity. Such behaviour is called reciprocity law failure. In this article a simple probabilistic model for reciprocity failure is presented which incorporates both high and low intensity failure. The flexibility of the model inherent in its simplicity allows more sophisticated models to be constructed.     

Reliability Evaluation of a Multi-state Network with Multiple Sinks under Individual Accuracy Rate Constraint

From the viewpoint of service level agreements (SLAs), Internet service providers and customers are gradually focusing on transmission accuracy. The Internet service provider should provide the specific bandwidth and individual accuracy rate requirement by their SLAs to each customer. This paper mainly evaluates the system reliability that a stochastic computer network can fulfill all requirements at all sinks. An efficient algorithm is proposed to generate the lower boundary points, minimal capacity vectors satisfying the demand and accuracy rate requirement for all sinks. The system reliability can be computed in terms of such points by applying recursive sum of disjoint products.     

A New Inference Framework for Dependency Networks

Dependency networks (DNs) have been receiving more attention recently because their structures and parameters can be easily learned from data. The full conditional distributions (FCDs) are known conditions of DNs. Gibbs sampling is currently the most popular inference method on DNs. However, sampling methods converge slowly and it can be hard to diagnose their convergence. In this article, we introduce a set of linear equations to describe the relations between joint probability distributions (JPDs) and FCDs. These equations provide a novel perspective to understand reasoning on DNs. Based on these linear equations, we develop both exact and approximate algorithms for inference on DNs. Experiments show that the proposed approximate algorithms can produce effective results by maintaining low computational complexity.     

基于社会资本理论的农民信任状况及培育研究

基于对1 273个农民的调查,从社会资本理论视角实证分析农民信任的影响因素及其培育对策。因子分析和均值分析发现:农民的信任程度可以分为特殊信任、一般信任和制度信任,农民的信任状况呈现出特殊信任水平高、制度信任水平居中、一般信任水平低的格局;回归分析发现:农民的特殊信任取决于社会网络和互惠状况,一般信任和制度信任受制于社团参与和互惠状况。为此,政府可通过强化正式制度的形塑作用,发展农村民间组织和恢复农村传统互惠规范等方式,以培育农民的信任程度。     

Additional bowman-shenton approximate percentage points for pearson distributions based on pearson type vi

The Bowman and Shenton approximate percentage points for Pearson distributions are extended to include some cases for which the skewness β¹ exceeds four.Use is made of the reciprocity property existing between the Pearson Type VI distribution and the Type I distribution     

基于网络层次分析法的农产品第三方物流服务商评价

中国农产品物流问题突出,现状堪忧。依据农产品物流的定义及农产品物流具有相对独立性、季节性、必要性等基本特点,构建了农产品第三方物流服务商评价指标体系和基于网络层次分析法的多指标综合评价决策模型。结合实际案例,运用超级决策软件进行了数值计算和验证,评估不同方案,计算结果表明,该模型能够根据第三方物流企业的实际情况,有效地评价与选择物流服务商。     

An averaging approach to prediction

The problem of predicting a future observation based on an observed sample is discussed. As a device for eliminating the parameter from the conditional distribution of a future observation given the observed sample, we suggest averaging with respect to an exact or approximate confidence distribution function. It is shown that in many standard problems where an exact answer is available by other methods, the averaging method reproduces that exact answer. When the exact answer is not easily available, the averaging method gives a simple and systematic approach to the problems. Applications to life data from exponential distribution and regression problems are examined.     

Best Practices for Presentation of E-journal Titles on Provider Web Sites and in Other E-content Products

As a result of inaccurate displays of journal metadata in e-content access tools and on Web sites, researchers and readers do not find the content they are seeking, and the full value of e-content services is not realized. A group will be formed later this year to develop a set of NISO best practices for presentation of e-journal titles, provision of correct ISSN information, and other basic bibliographic data on provider Web sites and in other e-content products.     

On the Use of the Concentration Function in Medical Fraud Assessment

We propose a simple, but effective, tool to detect possible anomalies in the services prescribed by a health care provider (HP) compared to his/her colleagues in the same field and environment. Our method is based on the concentration function that is an extension of the Lorenz curve widely used in describing uneven distribution of wealth in a population. The proposed tool provides a graphical illustration of a possible anomalous behavior of the HPs and it can be used as a prescreening device for further investigations of potential medical fraud.     

Some Sampling Properties of a Model for Income Distribution

A recently proposed model for describing the distribution of income over a population, based on the Burr distribution, has been shown to fit better than the commonly used lognormal or gamma distributions. The current article extends that analysis by deriving the large-sample properties of the maximum likelihood estimates for this three-parameter model. Consequently, resulting confidence intervals for some measures of income inequality (including the Gini index) are used to further test the model's validity, as well as to examine apparent trends in inequality over time. Since these properties depend on the way the income data are grouped and censored, implications for choosing data-report intervals can be analyzed. Specifically, a choice between two common methods of reporting the data is shown to have an important impact on Gini index estimates.     

An Extended Binomial Distribution with Applications

Based on Skellam (Poisson difference) distribution, an extended binomial distribution is introduced as a byproduct of extending Moran's characterization of Poisson distribution to the Skellam distribution. Basic properties of the distribution are investigated. Also, estimation of the distribution parameters is obtained. Applications with real data are also described.     

Some Comments on Hassairi et al.'s “Implicit Distributions and Estimation”

In social interaction studies, one commonly encounters repeated displays of behaviors along with their duration data. Statistical methods for the analysis of such data use either parametric (e.g., Weibull) or semi-nonparametric (e.g., Cox) proportional hazard models, modified to include random effects (frailty) which account for the correlation of repeated occurrences of behaviors within a unit (dyad). However, dyad-specific random effects by themselves are not able to account for the ordering of event occurrences within dyads. The occurrence of an event (behavior) can make further occurrences of the same behavior to be more or less likely during an interaction. This article develops event-dependent random effects models for analyzing repeated behaviors data using a Bayesian approach. The models are illustrated by a dataset relating to emotion regulation in families with children who have behavioral or emotional problems.     

Best Practices for Presentation of E-journal Titles on Provider Web Sites and in Other E-content Products

Abstract

As a result of inaccurate displays of journal metadata in e-content access tools and on Web sites, researchers and readers do not find the content they are seeking, and the full value of e-content services is not realized. A group will be formed later this year to develop a set of NISO best practices for presentation of e-journal titles, provision of correct ISSN information, and other basic bibliographic data on provider Web sites and in other e-content products.     

Transforming the exponential by minimizing the sum of the absolute differences

This work presents an optimal value to be used in the power transformation to transform the exponential to normality for statistical process control (SPC) applications. The optimal value is found by minimizing the sum of absolute differences between two distinct cumulative probability functions. Based on this criterion, a numerical search yields a proposed value of 3.5142, so the transformed distribution is well approximated by the normal distribution. Two examples are presented to demonstrate the effectiveness of using the transformation method and its applications in SPC. The transformed data are almost normally distributed and the performance of the individual charts is satisfactory. Compared to charts that use the original exponential data and probability control limits, the individual charts constructed using the transformed distribution are superior in appearance, ease of interpretation and implementation by practitioners.     

New measures of clumpiness for incidence data

In recent years, growing attention has been placed on the increasing pattern of ‘clumpy data’ in many empirical areas such as financial market microstructure, criminology and seismology, and digital media consumption to name just a few; but a well-defined and careful measurement of clumpiness has remained somewhat elusive. The related ‘hot hand’ effect has long been a widespread belief in sports, and has triggered a branch of interesting research which could shed some light on this domain. However, since many concerns have been raised about the low power of the existing ‘hot hand’ significance tests, we propose a new class of clumpiness measures which are shown to have higher statistical power in extensive simulations under a wide variety of statistical models for repeated outcomes. Finally, an empirical study is provided by using a unique dataset obtained from Hulu.com, an increasingly popular video streaming provider. Our results provide evidence that the ‘clumpiness phenomena’ is widely prevalent in digital content consumption, which supports the lore of ‘bingeability’ of online content believed to exist today.     

Current records and record range with some applications

In a sequence of independent and identically distributed (iid) random variables, the upper (lower) current records and record range are studied. We derive general recurrence relations between the single and product moments for the upper and lower current records based on Weibull and positive Weibull distributions, as well as Pareto and negative Pareto distributions, respectively. Moreover, some asymptotic results for general current records are established. In addition, a recurrence relation and an explicit formula for the moments of record range based on the exponential distribution are given. Finally, numerical examples are presented to illustrate and corroborate theoretical results.     

The General Segmented Distribution

We develop a distribution supported on a bounded interval with a probability density function that is constructed from any finite number of linear segments. With an increasing number of segments, the distribution can approach any continuous density function of arbitrary form. The flexibility of the distribution makes it a useful tool for various modeling purposes. We further demonstrate that it is capable of fitting data with considerable precision—outperforming distributions recommended by previous studies. We suggest that this distribution is particularly effective in fitting data with sufficient observations that are skewed and multimodal.     

A Bayesian inference of P(λ1<λ2) for two Poisson parameters

The statistical inference drawn from the difference between two independent Poisson parameters is often discussed in the medical literature. However, such discussions are usually based on the frequentist viewpoint rather than the Bayesian viewpoint. Here, we propose an index θ=P(λ_{1, post}<λ_{2, post}), where λ_{1, post} and λ_{2, post} denote Poisson parameters following posterior density. We provide an exact and an approximate expression for calculating θ using the conjugate gamma prior and compare the probabilities obtained using the approximate and the exact expressions. Moreover, we also show a relation between θ and the p-value. We also highlight the significance of θ by applying it to the result of actual clinical trials. Our findings suggest that θ may provide useful information in a clinical trial.