• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.521-529
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• 2013

The acceptance of the test of the homogeneity for panel time series models allows for the pooling of the series to achieve parsimony. In this paper, we introduce a panel bilinear time series model as well as derive the stationary condition and the limiting distribution of the test statistic of the homogeneity test for the model. For the applications study, we use Korea Mumps data from January 2001 to December 2008. Finally, we perform test of homogeneity for the panel data with 8 independent bilinear time series.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.257-266
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• 2016

Random Coefficient Autoregressive models (RCA) have attracted increased interest due to the wide range of applications in biology, economics, meteorology and finance. We consider an RCA as an appropriate model for non-linear properties and better than an AR model for linear properties. We study the methods of RCA parameter estimation. Especially we proposed the special case that an random coefficient ${\phi}(t)$ has the initial value ${\phi}(0)$ in the RCA model. In practical study, we estimated the parameters and compared Prediction Error Sum of Squares (PRESS) criterion between AR and RCA using Korean Mumps data.

• Communications for Statistical Applications and Methods
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• v.17 no.2
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• pp.263-273
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• 2010

Missing values in time series can be treated as unknown parameters and estimated by maximum likelihood or as random variables and predicted by the conditional expectation of the unknown values given the data. The purpose of this study is to impute missing values which are regarded as the maximum likelihood estimator and random variable in incomplete data and to compare with two methods using ARMA and STAR model. For illustration, the Mumps data reported from the national capital region monthly over the years 2001~2009 are used, and estimate precision of missing values and forecast precision of future data are compared with two methods.

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1163-1170
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• 2014

The concepts and structure of intermittent panel time series data are introduced. We suggest a Wald test statistic for the test of homogeneity for intermittent panel first order autoregressive model and its limit distribution is derived. We consider the fitting the model with pooling data using sample mean at the time point if homogeneity for intermittent panel AR(1) is satisfied. We performed simulations to examine the limit distribution of the homogeneity test statistic for intermittent panel AR(1). In application, we fit the intermittent panel AR(1) for panel Mumps data and investigate the test of homogeneity.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.117-123
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• 2011

Purpose : We investigated the change of antibody titer to measles, mumps and rubella according to age after vaccination. Methods : The IgG antibody titers to measles, mumps and rubella were tested on the residual serum from patients aged 7-20 years old after routine laboratory testing in the hospital with informed consent from the parents. Results : Antibody to measles was present in 275 cases out of 408 cases with a positive rate of 67.4%, the mean IgG titer was 2.77${\pm}$1.18 Index. Antibody to mumps was present in 112 cases out of 408 cases with a positive rate of 27.5%, the mean IgG titer was 2.08${\pm}$1.29 Index. Antibody to rubella was present in 367 cases out of 408 cases with a positive rate of 90.0%, the mean IgG titer was 60.46${\pm}$63.47 IU/mL. Conclusion : It is important to maintain a high rate of vaccination coverage in order to prevent an outbreak of measles, mumps, or rubella. It is also important to stress the maintenance of vaccination records for further reference.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1115-1117
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• 2005

This paper describes the three dimension model and simulation results of a thermal actuator based on polyMUMPs process, known as thermal multimorph actuator. The device has potential application in micro-transducers such as atomic force microscope (AFM) tip and scanning tunneling microscope (STM) tip. This device made of a multi-layer materials stack together with consisted of polysilicon, $SiO_2$ and gold. A mask layout design, three dimension model and simulation results are reported and discussed.

• Journal of Preventive Medicine and Public Health
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• v.33 no.3
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• pp.313-322
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• 2000

Objectives : To estimate mumps incidence during the study period and to evaluate the completeness of case reporting. Methods : Capture-recapture methods, originally developed for counting wildlife animals, were used. The data sources were 1) the National Notifiable Communicable Disease Reporting System (NNCDRS; 848 cases), 2) the School Health Reporting System, temporarily administered by the Division of Education (SHRS; 1,026 cases), and 3) a survey of students (785 cases). We estimated the number of unobserved mumps cases by matching the three data sources and fitting loglinear models to the data. We then determined the estimated total number of mumps cases by adding this to the number of observed cases. Completeness was defined as the proportion of observed cases from each source to the total of estimated cases. Results : The total number of observed cases was 1,844 and the total number of estimated cases was 1,935 (95%, CI: $1,878\sim2,070$). The overall completeness was 43.8% of the NNCDRS, 53.0% of the SHRS, and 40.6% of the survey. However, completeness varied by area and age. Conclusion : Although the completeness of NNCDRS data appeared higher than in the past, it is difficult to generalize this result In Korea, it is possible to estimate the size of health hazards relatively cheaply and quickly, by applying capture-recapture methods to various data using a multiple data collection system.

• The Korean Journal of Applied Statistics
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• v.20 no.1
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• pp.91-102
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• 2007

The major purpose of this article is to formulate a class of Space Time Autoregressive Moving Average(STARMA) model and Space Time Bilinear model(STBL), to discuss some of the their statistical properties such as model, identification approaches, some procedure for estimation and the predictions, and to compare the STARMA model with the STBL model. For illustration, The Mumps data reported from eight city & provinces monthly over the years 2001-2006 are used and the result from STARMA and STBL model are compared with using SSF(Sum of Square Prediction Error).

• Communications for Statistical Applications and Methods
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• v.16 no.1
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• pp.31-40
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• 2009

Spatial time series data can be viewed either as a set of time series collected simultaneously at a number of spatial locations. In this paper, We estimate the parameters of spatial time autoregressive moving average (SIARMA) process by method of Gibbs sampling. Finally, We apply this method to a set of U.S. Mumps data over a 12 states region.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.225-231
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• 1997

Purpose: To evaluate the postnatal changes of serum levels of mumps- and rubella-specific IgG antibody in unvaccinated infants, this study was performed using enzyme linked immunosorbent assay(ELISA). The sera were collected from 103 unvaccinated infants under 15 months of age. The results obtained were as follows. 1) The seropositivities and the levels of mumps specific IgG decreased by ages, 70.6% in month, 50.0% in 2~3 months, 6.7% in 4~5 months and 0% after 6 months of age respectively. 2) The seropositivities of rubella-specific IgG were 58.8 % in 1 month, 70% in 2~3 months, 13.3% in 4~5 months, and 0% after 6 months of ages in unvaccinated infants respectively. 3) The seropositivities and antibody levels of mumps and rubella specific IgG had significantly decreased with age, and there was negative correlation between ages of infants and mumps or rubella-specific IgG levels(correlation coefficient r=-0.500, P < 0.001). Conclusions: The seropositivities of transplacental antibodies of mumps and rubella in unvaccinated infants were 0% after 6 months of age. These transplacental antibodies disappeared earlier age than we had thought.