• Title/Summary/Keyword: incomplete data

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Estimation of Conditional Kendall's Tau for Bivariate Interval Censored Data

  • Kim, Yang-Jin
    • Communications for Statistical Applications and Methods
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    • v.22 no.6
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    • pp.599-604
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    • 2015
  • Kendall's tau statistic has been applied to test an association of bivariate random variables. However, incomplete bivariate data with a truncation and a censoring results in incomparable or unorderable pairs. With such a partial information, Tsai (1990) suggested a conditional tau statistic and a test procedure for a quasi independence that was extended to more diverse cases such as double truncation and a semi-competing risk data. In this paper, we also employed a conditional tau statistic to estimate an association of bivariate interval censored data. The suggested method shows a better result in simulation studies than Betensky and Finkelstein's multiple imputation method except a case in cases with strong associations. The association of incubation time and infection time from an AIDS cohort study is estimated as a real data example.

Restricted maximum likelihood estimation of a censored random effects panel regression model

  • Lee, Minah;Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
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    • v.26 no.4
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    • pp.371-383
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    • 2019
  • Panel data sets have been developed in various areas, and many recent studies have analyzed panel, or longitudinal data sets. Maximum likelihood (ML) may be the most common statistical method for analyzing panel data models; however, the inference based on the ML estimate will have an inflated Type I error because the ML method tends to give a downwardly biased estimate of variance components when the sample size is small. The under estimation could be severe when data is incomplete. This paper proposes the restricted maximum likelihood (REML) method for a random effects panel data model with a censored dependent variable. Note that the likelihood function of the model is complex in that it includes a multidimensional integral. Many authors proposed to use integral approximation methods for the computation of likelihood function; however, it is well known that integral approximation methods are inadequate for high dimensional integrals in practice. This paper introduces to use the moments of truncated multivariate normal random vector for the calculation of multidimensional integral. In addition, a proper asymptotic standard error of REML estimate is given.

Quantifying Values from BIM-projects life cycle with cloud-based computing

  • Choi, Michelle Mang Syn;Kim, Inhan
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.271-275
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    • 2015
  • A variety of evaluation application and initiatives on the adoption of Building Information Modelling (BIM) have been introduced in recent years. Most of which however, focused mainly on evaluating design to construction phase-processes, or BIM utilization performances. Through studying existing publications, it is found that continuous utilization of BIM data throughout the building's life cycle is comparatively less explored or documented. Therefore, this study looks at improving this incomplete life cycle condition with the concept that accumulated BIM data should be carried forward and statistically quantified for cross comparison, in order to facilitate practitioners to better improve the projects the future. Based on this conceptual theory of moving towards a closedloop BIM building life cycle, this study explores, through existing literature, the use of cloud based computing as the means to quantify and adaptively utilize BIM data. Categorization of BIM data relations in adaptive utilization of BIM data is then suggested as a initial step for enhancing cross comparison of BIM data in a cloud environment.

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Large tests of independence in incomplete two-way contingency tables using fractional imputation

  • Kang, Shin-Soo;Larsen, Michael D.
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.4
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    • pp.971-984
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    • 2015
  • Imputation procedures fill-in missing values, thereby enabling complete data analyses. Fully efficient fractional imputation (FEFI) and multiple imputation (MI) create multiple versions of the missing observations, thereby reflecting uncertainty about their true values. Methods have been described for hypothesis testing with multiple imputation. Fractional imputation assigns weights to the observed data to compensate for missing values. The focus of this article is the development of tests of independence using FEFI for partially classified two-way contingency tables. Wald and deviance tests of independence under FEFI are proposed. Simulations are used to compare type I error rates and Power. The partially observed marginal information is useful for estimating the joint distribution of cell probabilities, but it is not useful for testing association. FEFI compares favorably to other methods in simulations.

A structural model updating method using incomplete power spectral density function and modal data

  • Esfandiari, Akbar;Chaei, Maryam Ghareh;Rofooei, Fayaz R.
    • Structural Engineering and Mechanics
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    • v.68 no.1
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    • pp.39-51
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    • 2018
  • In this study, a frequency domain model updating method is presented using power spectral density (PSD) data. It uses the sensitivity of PSD function with respect to the unknown structural parameters through a decomposed form of transfer function. The stiffness parameters are captured with high accuracy through solving the sensitivity equations utilizing the least square approach. Using numerically noise polluted data, the model updating results of a truss model prove robustness of the method against measurement and mass modelling errors. Results prove the capabilities of the method for parameter estimation using highly noise polluted data of low ranges of excitation frequency.

Imputation Using Factor Score Regression

  • Lee, Sang-Eun;Hwang, Hee-Jin;Shin, Key-Il
    • Communications for Statistical Applications and Methods
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    • v.16 no.2
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    • pp.317-323
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    • 2009
  • Recently not even government polices but small town decisions are based on the survey data/information, so the most of government agencies/organizations demand various sample surveys in each fields for more detail information. However in conducting the sample survey, nonresponse problem rises very often and it becomes a major issue on judging the accuracy of survey. For that matters, one solution ran be using the administration data. However unfortunately most of administration data are restricted to the common users. The other solution can be the imputation. Therefore several method, of imputation are studied in various fields. In this study, in stead of the simple regression imputation method which is commonly used, factor score regression method is applied specially to the incomplete data which have the unit and item misting values in survey data. Here for simulation study, Consumer Expenditure Surveys in Korea are used.

Non-manifold Modeling Data Structure Based on Open Inventor (Open Inventor에 기초한 비다양체 모델링 자료구조)

  • 박상호;이호영;변문현
    • Korean Journal of Computational Design and Engineering
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    • v.3 no.3
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    • pp.154-160
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    • 1998
  • In this study, we implement the prototype modeler with non-manifold data structure using Open Inventor. In these days, Open Inventor is a popular tool for computer graphics applications, even though Open Inventor could not store topological information including a non-manifold data structure which can represent an incomplete three dimensional shape such as a wireframe and a dangling surface during designing. Using Open Inventor, our modeler can handle a non-manifold model whose data structure is based on the radial edge data structure. A model editor is also implemented as an application which can construct a non-manifold model from two dimensional editing.

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Assessment and Validation of the Reliability of Quality Measurement System for Wireless Data Services (무선데이터 서비스 품질 측정 시스템의 신뢰성 검증 및 평가)

  • Choi, Dong-Hwan;Park, Seok-Cheon
    • Journal of Information Technology Services
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    • v.11 no.1
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    • pp.239-246
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    • 2012
  • The user increases around the WiBro and in which the mobile broad band service is the wireless internet base technology HSDPA, that is the cellular phone foundation technique, and moreover the issue about the user effective quality guarantee emerges but the quality control of the wireless network is the incomplete actual condition. Therefore, the reliability verification according to the development of the system for the performance measure for the continued wireless data service and it and evaluation are needed for the quality control. In this paper, the wireless data service quality measurement system was implemented with the design. The same test environment as the existing network performance measurement program was built for the reliability verification of the embodied device for measuring quality and evaluation and the cost performance was performed. It could confirm that design and embodied wireless data service quality measurement system operated accurately in this paper through the quality measure result value analysis.

Correction of Bilateral Cleft Lip Using Modified Noordhoff Technique (개선된 Noordhoff 방법을 이용한 양측성 구순열의 교정)

  • Cho, Byung Chae;Lee, Yong Jig
    • Archives of Plastic Surgery
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    • v.33 no.4
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    • pp.399-406
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    • 2006
  • Purpose: The authors accessed the anthropometric measurements of fourty non-cleft normal a three-month-old infant and using this obtained data as a basic guideline, authors applied the modified Noordhoff technique for the treatment of bilateral cleft lip. Methods: Over a period of 10 years, a total of 21 bilateral cleft lips were operated. 13 cases of complete and 8 cases of incomplete bilateral cleft lip and palate. In the complete type of bilateral cleft palate, elastic head cap and passive intraoral appliance were applied at 1 to 2 week of age for 2 months duration. The definitive cheiloplasty was performed at 3 months of age using the modified Noordhoff technique. Results: After a follow-up period ranging one to nine years, most patients presented with cosmetically and functionally satisfying results, with an exception of two cases where an undesired peaking effect of the vermilion and dimpling of the vermilion mucosa was encountered. Conclusion: Accessing the anthropometric measurements of fourty non-cleft normal three-month-old infant and using this obtained dara as a guideline, the modified Noordhoff technique can be applied to either complete or incomplete bilaterally cleft lip providing more naturally pleasing and cosmetically satisfying scars that lie in harmony with the philtral ridges, lip tubercle positioned just below the vermilion and a distinct white line and Cupid's bow.

Analysis on the Fire Accident of Vehicle Due to Damage of Connector and wiring on an Anti-lock Brake System(ABS) Module (ABS 모듈의 접속부 및 전원배선 손상으로 인한 차량화재 사고사례 분석)

  • Park, Nam-Kyu;Kim, Jin-Pyo;Nam, Jung-Woo;Park, Jong-Taek;Song, Jae-Yong
    • Journal of the Korean Society of Safety
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    • v.32 no.5
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    • pp.13-19
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    • 2017
  • In this paper, study of vehicle fire cases caused by connector and power wiring of anti-lock brake system(ABS) module damage is presented. The purpose of ABS module is to improve braking and steering ability under sudden stop of the vehicle by repeatedly activating and releasing the brake with electric signal via electric control unit. The electric control unit for ABS may experience incomplete contact between power line and signal line or electrical breakdown on the printed circuit board by undergoing repetitive signal change which would consequently result in electrical heat and spark, eventually leading to automotive fire. Therefore, the purpose of this paper is to provide fundamental data by analyzing connector and power wiring of ABS module damage conducive to the precise investigation on the cause of vehicle fire.