• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.23-33
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• 2008

This paper proposes an approach to monitoring and scheduling methods for repetitive MIMO-FIFO DESs. We use max-plus algebra for modeling and formulation, known as an effective approach for controller design for this type of system. Because a certain type of linear equations in max-plus algebra can represent the system's behavior, the principal concerns in past researches were how to solve the equations. However, the researches focused mainly on analyses of the relation between inputs and outputs of the system, which implies that the changes or the slacks of internal states were not clarified well. We first examine several properties of the corresponding state variables, which contribute to finding and tracing the float times in each process. Moreover, we provide a rescheduling method that can take into account delays or changes of the internal states. These methods would be useful in schedule control or progress management.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.172-177
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• 2015

Purpose: This study aimed to analyze the epidemic period of RSV infection and evaluate the appropriate time of palivizumab immunoprophylaxis. Methods: From January 1991 to July 2012, nasopharyngeal (NP) aspirates were obtained from patients who visited Seoul National University Children's Hospital for respiratory symptoms. NP samples were used to detect respiratory viruses. Among them, we analyzed the positive number and detection rate of RSV infection in two-week interval. The beginning of RSV season was defined when RSV positive number was more than 4 and RSV detection rate was over 10%. From January 2007 to March 2014, we analyzed the starting time of palivizumab immunoprophylaxis for the infants at high risk. Results: The RSV detection rate was 2,013/21,698 (9.69%) over 22 years. The median RSV season was from $2^{nd}-3^{rd}$ week of October to $1^{st}-2^{nd}$ week of February. The earliest starting week was the 3rd week of July in year 2001, and the latest end week was the 3rd week of May in year 1990. Palivizumab immunoprophylaxis was initiated most frequently at the 3rd week of October (18.7%). However, the percentage of starting palivizumab on the 1st week of September has increased from 3.8% in the year 2007 to 14.1% in 2013. Conclusions: The year to year variability of RSV season exists. The starting time of palivizumab immunoprophylaxis should be adjusted based on the season of RSV epidemic.