نتایج جستجو برای: Missing Data

تعداد نتایج: 2444874  

Journal: :journal of optimization in industrial engineering 2015
reza kazemi matin roza azizi

in the classical data envelopment analysis (dea) models, inputs and outputs are assumed as known variables, and these models cannot deal with unknown amounts of variables directly. in recent years, there are few researches on handling missing data. this paper suggests a new interval based approach to apply missing data, which is the modified version of kousmanen (2009) approach. first, the prop...

Journal: :iranian journal of public health 0
m mirmohammadkhani dept. of epidemiology and biostatistics, school of public health, tehran university of medical scien a rahimi foroushani dept. of epidemiology and biostatistics, school of public health, tehran university of medical scien f davatchi dept. of internal medicine, school of medicine, tehran university of medical sciences, tehran, iran k mohammad dept. of epidemiology and biostatistics, school of public health, tehran university of medical scien a jamshidi dept. of internal medicine, school of medicine, tehran university of medical sciences, tehran, iran a tehrani banihashemi rheumatology research center, tehran, iran

background: the aim of the article is demonstrating an application of multiple imputation (mi) for handling missing clinical data in the setting of rheumatologic surveys using data derived from 10291 people participating in the first phase of the community oriented program for control of rheumatic disorders (copcord) in iran . methods: five data subsets were produced from the original data set....

Journal: :iranian journal of public health 0
mr baneshi reserch center for modeling in health, kerman university of medical sciences, kerman, iran h faramarzi shiraz hiv/aids research center, shiraz university of medical sciences, shiraz m marzban research center for traditional medicine and history of medicine, shiraz university of medical scien

background: diagnostic models are frequently used to assess the role of risk factors on disease complications, and therefore to avoid them. missing data is an issue that challenges the model making. the aim of this study was to develop a diagnostic model to predict death in hiv/ aids patients when missing data exist. methods: hiv patients (n=1460) referred to voluntary consoling and testing cen...

Multivariate time series data are found in a variety of fields such as bioinformatics, biology, genetics, astronomy, geography and finance. Many time series datasets contain missing data. Multivariate time series missing data imputation is a challenging topic and needs to be carefully considered before learning or predicting time series. Frequent researches have been done on the use of diffe...

Journal: :international journal of health policy and management 2013
saiedeh haji-maghsoudi ali-akbar haghdoost azam rastegari mohammad reza baneshi

background policy makers need models to be able to detect groups at high risk of hiv infection. incomplete records and dirty data are frequently seen in national data sets. presence of missing data challenges the practice of model development. several studies suggested that performance of imputation methods is acceptable when missing rate is moderate. one of the issues which was of less concern...

Reza Kazemi Matin, Roza Azizi

In the classical data envelopment analysis (DEA) models, inputs and outputs are assumed as known variables, and these models cannot deal with unknown amounts of variables directly. In recent years, there are few researches on handling missing data. This paper suggests a new interval based approach to apply missing data, which is the modified version of Kousmanen (2009) approach. First, the prop...

Journal: :iranian journal of public health 0
mr baneshi a talei

background: prognostic models have clinical appeal to aid therapeutic decision making. two main practical challenges in development of such models are assessment of validity of models and imputation of missing data. in this study, importance of imputation of missing data and application of bootstrap technique in development, simplification, and assessment of internal validity of a prognostic mo...

Journal: :journal of paramedical sciences 0
alireza akbarzadeh baghban department of basic sciences, school of rehabilitation sciences, shahid beheshti university of medical sciences, tehran erfan ghasemi department of biostatistics, faculty of paramedical sciences, shahid beheshti university of medical sciences, tehran farid zayeri proteomics research center, faculty of paramedical sciences, shahid beheshti university of medical sciences, tehran saeed asgary iranian center of endodontic research, dental research center, shahid beheshti university of medical sciences, tehran mahshid namdari department of biostatistics, faculty of paramedical sciences, shahid beheshti university of medical sciences, tehran

in interventional or observational longitudinal studies, the issue of missing values is one of the main concepts that should be investigated. the researcher's main concerns are the impact of missing data on the final results of the study and the appropriate methods that missing values should be handled. regarding the role and the scale of the variable that missing values have been occurred and ...

Journal: :Journal of Pain and Symptom Management 2012

Journal: :Phlebology: The Journal of Venous Disease 2011

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