نتایج جستجو برای: imputation

تعداد نتایج: 16711  

Journal: :Inf. Sci. 2013
Ibrahim Berkan Aydilek Ahmet Arslan

Missing values in datasets should be extracted from the datasets or should be estimated before they are used for classification, association rules or clustering in the preprocessing stage of data mining. In this study, we utilize a fuzzy c-means clustering hybrid approach that combines support vector regression and a genetic algorithm. In this method, the fuzzy clustering parameters, cluster si...

Journal: :Biometrics 2002
Cheryl L Faucett Nathaniel Schenker Jeremy M G Taylor

We develop an approach, based on multiple imputation, to using auxiliary variables to recover information from censored observations in survival analysis. We apply the approach to data from an AIDS clinical trial comparing ZDV and placebo, in which CD4 count is the time-dependent auxiliary variable. To facilitate imputation, a joint model is developed for the data, which includes a hierarchical...

Journal: :CoRR 2018
Shehroz S. Khan Amir Ahmad Alex Mihailidis

Correspondence *Corresponding author Email: [email protected] Presence of missing values in a dataset can adversely affect the performance of a classifier; it deteriorates rapidly as missingness increases. Single and Multiple Imputation (MI) are normally performed to fill in the missing values. In this paper, we present several variants of combining MI and bootstrapping to create ensembl...

2016
Wenzhi Li Wei Xu Shaohua He Li Ma Qing Song

The data presented in this article is related to the research article entitled "High-accuracy haplotype imputation using unphased genotype data as the references" which reports the unphased genotype data can be used as reference for haplotyping imputation [1]. This article reports different implementation generation pipeline, the results of performance comparison between different implementatio...

2012
Zhixu Li Mohamed A. Sharaf Laurianne Sitbon Shazia Wasim Sadiq Marta Indulska Xiaofang Zhou

In this paper, we present WebPut, a prototype system that adopts a novel web-based approach to the data imputation problem. Towards this, Webput utilizes the available information in an incomplete database in conjunction with the data consistency principle. Moreover, WebPut extends effective Information Extraction (IE) methods for the purpose of formulating web search queries that are capable o...

2004
Martin Kroh

Incomplete data is a common problem of survey research. Recent work on multiple imputation techniques has increased analysts’ awareness of the biasing effects of missing data and has also provided a convenient solution. Imputation methods replace non-response with estimates of the unobserved scores. In many instances, however, non-response to a stimulus does not result from measurement problems...

2017
Shahla Faisal Gerhard Tutz

Missing values are a common phenomenon in all areas of applied research. While various imputation methods are available for metrically scaled variables, methods for categorical data are scarce. An imputation method that has been shown to work well for high dimensional metrically scaled variables is the imputation by nearest neighbor methods. In this paper, we extend the weighted nearest neighbo...

Journal: :Journal of animal science 2012
Y Huang C Maltecca J P Cassady L J Alexander W M Snelling M D MacNeil

The objective of this study was to investigate alternative methods of designing and using reduced SNP panels for imputing SNP genotypes. Two purebred Hereford populations, an experimental population known as Line 1 Hereford (L1, n = 240) and registered Hereford with American Hereford Association (AHA, n = 311), were used. Using different reference samples of 62 to 311 animals with 39,497 SNP on...

2011
Hassan MK Ghomrawi Lisa A Mandl John Rutledge Michael M Alexiades Madhu Mazumdar

BACKGROUND Standard mean imputation for missing values in the Western Ontario and Mc Master (WOMAC) Osteoarthritis Index limits the use of collected data and may lead to bias. Probability model-based imputation methods overcome such limitations but were never before applied to the WOMAC. In this study, we compare imputation results for the Expectation Maximization method (EM) and the mean imput...

Journal: :Journal of dairy science 2015
A García-Ruiz F J Ruiz-Lopez G R Wiggans C P Van Tassell H H Montaldo

The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNP) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local population of 2,011 genotyped Mexican Holsteins, (2) animals in scenario 1 plus 866 Holsteins in the US ...

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