An Empirical Comparison of Estimating Methods for the Ramberg–Osgood EIV Model

The standard tensile test is one of the most frequent tools performed for the evaluation of mechanical properties of metals. An empirical model proposed by Ramberg and Osgood fits the tensile test data using a nonlinear model for the strain in terms of the stress. It is an Error-In-Variables (EIV) model because of the uncertainty affecting both strain and stress measurement instruments. The SIMEX, a simulation-based method for the estimation of model parameters, is powerful in order to reduce bias due to the measurement error in EIV models. The plan of this article is the following. In Sec. 2, we introduce the Ramberg–Osgood model and another reparametrization according to different assumptions on the independent variable. In Sec. 3, there is a summary of SIMEX method for the case at hand. Section 4 is a comparison between SIMEX and others estimating methods in order to highlight the peculiarities of the different approaches. In the last section, there are some concluding remarks.     

Exit, Voice, Loyalty in Transition: A Theoretical Framework

On the grounds of borrowing and reforming Hirschman’s terminology, ‘exit, voice, loyalty’, we show both a conceptual and a methodological framework that can be used to raise questions in transitology studies. These issues include the following points: are there any models being developed concerning the transition countries?; are there any similar models in Western Europe?; is there any convergence between the models of both Eastern and Western Europe? If the answer to the last issue is yes, then in which areas? Or if it is a no, is it true that a special economic, social and also political system is developing in Eastern Europe? Another issue concerns how strong the growth potential of the different models is. It also examines which are the successful models and which are not, and what is the role of the economic and political elite in the development of these models. This study includes only the theoretical framework.     

Optimal estimation of a finite population mean under generalized random permutation models

Employing certain generalized random permutation models and a general class of linear estimators of a finite population mean, it is shown that many of the conventional estimators are “optimal” in the sense of minimum average mean square error. Simple proofs are provided by using a well-known theorem on UMV estimation. The results also cover certain simple response error situations.     

京剧“样板戏”唱腔体系之探析

京剧"样板戏"相对传统的京剧板式来说,其最大的艺术成就就是它在唱腔的现代化方面进行了空前的变革和创新:在传统的板式之外新创了许多新板式,极大地丰富了京剧的板腔体系和唱腔本身;在声腔体系中创新了乐句句式和套腔布局,空前地丰富了京剧唱腔的艺术表现功能;在唱腔设计中创造性地融入了特性音调,空前地强化了京剧唱腔的人物个性;在行腔技巧上一反传统戏"曲高和寡"的技巧化倾向,空前地强化了京剧唱腔的通俗化和亲和力,为京剧唱腔的创新提供了无可争辩的宝贵价值和不可多得的"样板"。     

面向动态完全竞争构建多维协同组合战略

现有战略管理理论以不完全竞争市场为前提条件,因而越来越难以应对日益激烈的超竞争环境.有甚于此,笔者的研究发现,在技术进步和收入增长效应足够大的情况下,传统上认定不会出现完全竞争的差别产品最终也会出现每个企业都按边际成本定价的动态完全竞争.面向动态完全竞争的战略管理的基本任务随之转为运用介观视野去发现并实施具备多维协同组合特性的新的商务模式,同时做到差异准确、成本领先、反应敏捷和分享得力.     

Innovations in teaching social work research

This article reviews the innovations in teaching research in social work education, including conceptual material and specific examples. There is attention to the ideological differences inherent in research and its instruction, methodology/technology innovations, and integrative and group approaches, among other developments. Examination of three major models of research instruction and their assumptions about the purpose of research in social work is presented. Discussion about ethical codes and curricular guidelines for social work programs in the United States and the United Kingdom provides a framework to understand the importance of teaching and learning research for the social work profession.     

Bayesian monitoring of local residual autocorrelations taking into account the run-length

This paper proposes new two-sided monitoring algorithms for detecting the presence of first order residual autocorrelations in Dynamic Normal Models. The methodology uses a Bayesian decision approach with loss function which takes into account the run-length of the process. The power and mean run-length of the proposed algorithms are analysed by Monte Carlo methods. The results obtained improve those corresponding to the monitoring algorithm for residual autocorrelations proposed in Gargallo and Salvador [2003. Monitoring residual autocorrelations in dynamic linear models. Comm. Statist. Simulation Comput. 32(4), 1079–1104.] with respect to the run-length, and also exhibit more homogeneous behaviour.     

Constrained production lot-size model with trade-credit policy: 'A comparison geometric programming approach via Lagrange'

In this paper our main objective is to investigate a deterministic inventory production lot-size model with a permissible delay in payment under a restriction. We analyse our deterministic inventory model under a restriction which will be assumed as the average inventory level. In fact we use in our analysis two approaches: the geometric programming approach; and the Lagrange method. Then a comparison between these two approaches is performed, which is our aim. Finally we deduce some previously published works of other researchers as special cases.     

Bayesian estimation procedure in multiprocess non-linear dynamic generalized model

The multiprocess dynamic model provides a good framework for the modeling and analysis of the time series that contains outliers arid is subject to abrupt changes in pattern. In this paper we extend the multiprocess dynamic generalized linear model to allow for a known non-linear parameter evolution and predictor functions. This is done by approximating the non-linear function by a linear function based on a first order Taylor series expansions. This model has nice properties such as insensitivity to outliers and quick reaction to abrupt changes of pattern.     

A network centrality bias: Central individuals in workplace networks have more supportive coworkers

Combining the results of two empirical studies, we investigate the role of alters’ motivation in explaining change in ego’s network position over time. People high in communal motives, who are prone to supportive and altruistic behavior in their interactions with others as a way to gain social acceptance, prefer to establish ties with co-workers occupying central positions in organizational social networks. This effect results in a systematic network centrality bias: The personal network of central individuals (individuals with many incoming ties from colleagues) is more likely to contain more supportive and altruistic people than the personal network of individuals who are less central (individuals with fewer incoming ties). This result opens the door to the possibility that the effects of centrality so frequently documented in empirical studies may be due, at least in part, to characteristics of the alters in an ego’s personal community, rather than to egos themselves. Our findings invite further empirical research on how alters’ motives affect the returns that people can reap from their personal networks in organizations.