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1.
Bartlett correction constitutes one of the attractive features of empirical likelihood because it enables the construction of confidence regions for parameters with improved coverage probabilities. We study the Bartlett correction of spatial frequency domain empirical likelihood (SFDEL) based on general spectral estimating functions for regularly spaced spatial data. This general formulation can be applied to testing and estimation problems in spatial analysis, for example testing covariance isotropy, testing covariance separability as well as estimating the parameters of spatial covariance models. We show that the SFDEL is Bartlett correctable. In particular, the improvement in coverage accuracies of the Bartlett‐corrected confidence regions depends on the underlying spatial structures. The Canadian Journal of Statistics 47: 455–472; 2019 © 2019 Statistical Society of Canada 相似文献
2.
Open innovation and absorptive capacity are two concepts based on the idea that companies can leverage the knowledge generated externally to improve their innovation performance. The aim of this paper is to analyse the joint effect of open innovation and absorptive capacity on a firm's radical innovation. Open innovation is expressed in terms of external search breadth and depth strategies and absorptive capacity is described by distinguishing between potential and realized absorptive capacity. In order to test our hypotheses, we carried out empirical research in firms operating in high-technology industries. The results indicate that internal routines and processes for absorbing external knowledge help explain radical innovation as they show a significant effect of potential and realized absorptive capacity. Also, there is a moderating effect of absorptive capacity on open innovation. Specifically, potential absorptive capacity exerts a positive effect on the relationship between external search breadth and depth and radical innovation. Realized absorptive capacity moderates the influence of external search breadth. These findings confirm the complementary nature of absorptive capacity and open innovation search strategies on radical innovation. 相似文献
3.
Safa Ali Ahmed Amar Recep Eryilmaz Halit Demir Serdar Aykan Canan Demir 《The aging male》2019,22(3):198-206
In this study, the antioxidant enzyme activities such as (SOD, GSH, and CAT) and malondialdehyde (MDA) level which is the end product of lipid peroxidation, were determined from the serum samples taken from patients diagnosed with prostate cancer Van Yuzuncu Y?l University Medical Faculty of Educational Research and Training Hospital and ?stanbul Bagcilar Education Research Hospital. The SOD, GSH, and CAT activity of patient groups was found significantly lower than the healthy control group in patients with prostate cancer (p?.05). Serum MDA level is found significantly high when compared to control groups. MDA levels increased in patients that suffer prostate cancer disorder. Whereas, firstly antioxidant enzymes activity of SOD, GSH and CAT have been decreased in control groups. Thus, we concluded that the cause of development of prostate cancer may be the result of an imbalance between the antioxidants and oxidative stress. As a result, SOD, CAT, GSH, and MDA may play an important role in the etiopathogenesis of prostate cancer. 相似文献
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Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances. 相似文献
6.
M. Y. Wong 《Journal of applied statistics》1995,22(1):3-8
The usual test of the equality of two slopes in a simple structural relation-ship is the test formed from the normal approximation using the Fisher information matrix, assuming two explanatory variables are independent. This paper examines the robustness if the explanatory variables are, in fact, dependent. A more efficient estimator is derived for a matched pair situation. 相似文献
7.
Constrained allocation problems with single-peaked preferences: An axiomatic analysis 总被引:1,自引:0,他引:1
Özgür Kıbrıs 《Social Choice and Welfare》2003,20(3):353-362
We introduce a new class of problems that contains two existing classes: allocation problems with single-peaked preferences
and bankruptcy problems. On this class, we analyze the implications of well-known properties such as Pareto optimality, strategy-proofness,
resource-monotonicity, no-envy, equal treatment of equals, and two new properties we introduce, hierarchical no-envy and independence
of nonbinding constraints. Unlike earlier literature, we consider rules that allow free-disposability. We present characterizations
of a rule we introduce on this domain. We relate this rule to well-known rules on the aforementioned subdomains. Based on
this relation, we present a characterization of a well-known bankruptcy rule called the constrained equal awards rule.
Received: 22 June 2000/Accepted: 21 March 2002
This paper is based on the first chapter of my Ph.D. thesis submitted to the University of Rochester. I wish to thank my
advisor, William Thomson, for helpful comments and suggestions. 相似文献
8.
The authors propose graphical and numerical methods for checking the adequacy of the logistic regression model for matched case‐control data. Their approach is based on the cumulative sum of residuals over the covariate or linear predictor. Under the assumed model, the cumulative residual process converges weakly to a centered Gaussian limit whose distribution can be approximated via computer simulation. The observed cumulative residual pattern can then be compared both visually and analytically to a certain number of simulated realizations of the approximate limiting process under the null hypothesis. The proposed techniques allow one to check the functional form of each covariate, the logistic link function as well as the overall model adequacy. The authors assess the performance of the proposed methods through simulation studies and illustrate them using data from a cardiovascular study. 相似文献
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