Bootstrap test of hypothesis for the multi-state models in survival analysis

Abstract

In the present paper we develop bootstrap tests of hypothesis, based on simulation, for the transition probability matrix arising in the context of a multi-state model. The bootstrap test statistic is based on the paper of Tattar and Vaman (2008 Tattar, P. N., Vaman, H. J. (2008). Testing transition probability matrix of a multi-state model with censored data. Lifetime Data Anal. 14(2):216–230.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), which develops a statistic for the testing problems concerning the transition probability matrix of the non homogeneous Markov process.     

On the Detection of Contemporaneous Relationships Among Multiple Time Series

A study is carried out of a sampling from a half-normal and exponential distributions to develop a test of hypothesis on the mean. Although these distributions are similar, the corresponding uniformly most paerful test statistics are different. The exact distributions of these statistics my be written in terms of the incomplete gamma function. If the experimental data my be fitted by either distributions, it is advisable to carryout the test based on the half-normal distribution as it is generally more powerful than the one based on the exponential one.     

Estimation of Time-Varying Long Memory Parameter Using Wavelet Method

Stationary long memory processes have been extensively studied over the past decades. When we deal with financial, economic, or environmental data, seasonality and time-varying long-range dependence can often be observed and thus some kind of non-stationarity exists. To take into account this phenomenon, we propose a new class of stochastic processes: locally stationary k-factor Gegenbauer process. We present a procedure to estimate consistently the time-varying parameters by applying discrete wavelet packet transform. The robustness of the algorithm is investigated through a simulation study. And we apply our methods on Nikkei Stock Average 225 (NSA 225) index series.     

Multiplicative Algorithms for Maximum Penalized Likelihood Inversion with Non Negative Constraints and Generalized Error Distributions

In many linear inverse problems the unknown function f (or its discrete approximation Θ _p×1), which needs to be reconstructed, is subject to the non negative constraint(s); we call these problems the non negative linear inverse problems (NNLIPs). This article considers NNLIPs. However, the error distribution is not confined to the traditional Gaussian or Poisson distributions. We adopt the exponential family of distributions where Gaussian and Poisson are special cases. We search for the non negative maximum penalized likelihood (NNMPL) estimate of Θ. The size of Θ often prohibits direct implementation of the traditional methods for constrained optimization. Given that the measurements and point-spread-function (PSF) values are all non negative, we propose a simple multiplicative iterative algorithm. We show that if there is no penalty, then this algorithm is almost sure to converge; otherwise a relaxation or line search is necessitated to assure its convergence.     

Accuracy Analysis of the Percentile Method for Estimating Non Normal Manufacturing Quality

We consider asymmetric kernel estimates based on grouped data. We propose an iterated scheme for constructing such an estimator and apply an iterated smoothed bootstrap approach for bandwidth selection. We compare our approach with competing methods in estimating actuarial loss models using both simulations and data studies. The simulation results show that with this new method, the estimated density from grouped data matches the true density more closely than with competing approaches.     

Robust Correlation Structure for Multivariate Failure Time Data

When incomplete repeated failure times are collected from a large number of independent individuals, interest is focused primarily on the consistent and efficient estimation of the effects of the associated covariates on the failure times. Since repeated failure times are likely to be correlated, it is important to exploit the correlation structure of the failure data in order to obtain such consistent and efficient estimates. However, it may be difficult to specify an appropriate correlation structure for a real life data set. We propose a robust correlation structure that can be used irrespective of the true correlation structure. This structure is used in constructing an estimating equation for the hazard ratio parameter, under the assumption that the number of repeated failure times for an individual is random. The consistency and efficiency of the estimates is examined through a simulation study, where we consider failure times that marginally follow an exponential distribution and a Poisson distribution is assumed for the random number of repeated failure times. We conclude by using the proposed method to analyze a bladder cancer dataset.     

The World Social Forum: the paradoxical quest for strength in plurality

ABSTRACT

In this reflexive essay, I explore how the present and the future of the World Social Forum are intimately related to the ability of its actors to acknowledge and actively address the inherent tensions of open spaces. The former must compose themselves articulating seemingly opposites: ideals shared within the World Social Forum vs. some practices not in accordance with its principles (enhanced in contexts of urgency); claimed horizontality vs. dynamic power relations; internal plurality vs. the need to act in unity to achieve systemic global change, amongst others. I will propose perspectives on how the strength of the WSF can be seen as its capacity to continue building radical hope for a positive shift of paradigm within progressive civil society: from divergences to resilient complementarities.     

Decrypting cultural nuances: using drama techniques from the theatre of the oppressed to strengthen cross cultural communication in social work students

ABSTRACT

Despite widening participation in social work education in the UK, social work students from black and minority ethnic (BME) backgrounds can find that they have less positive experiences on social work courses than their counterparts. This can happen when courses do not equip students to navigate the subtle rules of communication with service users that are premised on dominant UK values. As a consequence BME students can be assessed as having poor interpersonal skills and poor skills in engaging service users. However, the issue is often more one of cultural differences and high expectations of cultural integration than one of incompetence.

This paper reports on a drama workshop using techniques from the Theatre of the Oppressed to foster awareness of the complexities of cross cultural communication that BME students may face. The workshop facilitates insight into the nuances of culturally informed values that differ from dominant UK values.

Drawing on student workshop evaluations, the authors highlight the positive use of techniques from the Theatre of the Oppressed as a pro-active pedagogical approach to equipping BME students with insight and skill to circumnavigate cross cultural communication in practice and develop awareness of empowering strategies to combat negative paradigms about BME cultures.     

浅谈现代汉语与英语中双宾语结构构成的异同

双宾语在现代汉语中占据着一个非常重要的地位,比较现代汉语和英语中双宾语结构构成的异同,有助于我们更好地学习并利用现代汉语中的双宾语结构,也有助于理解和学习英语中的双宾语结构。本文先后探讨了现代汉语和英语中双宾语在结构上、动词、直接宾语、间接宾语方面的异同,对我们更好地学习和运用现代汉语中的双宾语有一定的帮助。