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Optimal tuberculosis prevention and control strategy from a mathematical model based on real data.
Choi, Sunhwa,Jung, Eunok Springer 2014 BULLETIN OF MATHEMATICAL BIOLOGY Vol.76 No.7
<P>A mathematical control model for the transmission dynamics of tuberculosis (TB) in South Korea is developed on the basis of the reported active-TB and relapse-TB incidence data. In this work, optimal control theory is used to propose optimal TB prevention and control strategy and rearrange the government TB budget for the best TB elimination plan. The impact of distancing, case finding, and/or case holding controls are investigated when the number of infected and infectious individuals are minimized, while the intervention costs are kept low. The implementation of optimal control measures shows that the distancing control, such as isolation of infectious people, early TB patient detection, and educational program/campaign for healthy control, is the most effective control factor for the prevention of TB transmission in South Korea.</P>
Estimating the reproductive number and the outbreak size of COVID-19 in Korea
Sunhwa Choi,Moran Ki 한국역학회 2020 Epidemiology and Health Vol.42 No.-
OBJECTIVES: Since the first novel coronavirus disease 2019 (COVID-19) patient in Korea was diagnosed on January 20, 2020, 30 patients were diagnosed until February 17, 2020. However, 5,298 additional patients were confirmed until March 4, 2020. Therefore, our objective was to estimate the reproduction number (R) and evaluate the effectiveness of preventive measures. METHODS: A COVID-19 transmission model (SEIHR) was established to suit the Korean outbreak. The number of daily confirmed cases in Daegu and North Gyeongsang Province (NGP), the main area of outbreak, was used. The first patient’ symptom onset date in the Daegu/NGP outbreak was assumed as January 22, 2020. The R according to the start date of the effect of preventive measures was estimated. RESULTS: The estimated R in Hubei Province, China, was 4.0281, whereas the estimated initial R in Korea was 0.555, but later in Daegu/NGP, the value was between 3.472 and 3.543. When the transmission period decreases from 4-day to 2-day, the outbreak ends early, but the peak of the epidemic increases, and the total number of patients does not change greatly. It was found that, if transmission rate decreases, the outbreak ends early, and the size of the peak and the total number of patients also decreases. CONCLUSIONS: To end the COVID-19 epidemic, efforts to reduce the spread of the virus, such as social distancing and wearing masks, are absolutely crucial with the participation of the public, along with the policy of reducing the transmission period by finding and isolating patients as quickly as possible through the efforts of the quarantine authorities.
EXPLORING HOW SERVICE AGENT TYPE AFFECTS GREEN CONSUMERS’ SATISFACTION
Sunhwa Choi,Youjae Yi 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07
As environmental pollution and natural resource depletion are seriously threatening human beings’ well-being, consumers’ concern about environmental issues has substantially increased. Accordingly, increasing consumers consider themselves to be environmentalists and support environmental protection by consuming green products. In response, more and more firms follow the popular trend by conducting green marketing practices. As a result, green markets are demonstrating greater growth compared to conventional markets these days. On the other hand, advances in artificial intelligence (AI) and robotics are transforming the way of consumer-firm interactions in various industries including the green industry. More and more industries and firms adopt AI agents to replace or assist human employees. Deposit the pervasive and rapid nature of the transformation, however, we have limited knowledge of how the transformation of consumer-firm interaction influences green product marketing practices. Accordingly, the current research aims to investigate how the adoption of AI agents in green marketing strategies impacts consumers’ responses and further explore which mechanism underlying the process. To examine our hypotheses, we conducted a series of studies, and we collected the data through an online survey platform. Our findings demonstrated that consumers’ reaction was sufficiently different when they interact with AI agent compared to human agent in a green consumption context. Our findings contribute to enriching prior literature on green and AI by integrating each other and also provide practical implications for marketers in the related industries.
The Optimal Strategies for Tuberculosis with Exogenous reinfection
Sunhwa CHOI,Eunok JUNG 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.2009 No.5
In this work we apply optimal control theory to the system of ordinary differential equations, which describes tuberculosis (TB) with exogenous reinfection, and optimal controls representing treatment or prevention. Using an objective function based on minimizing the infected individuals and the efforts, we characterize for the optimal control in the optimality system. To find best combination of controls, it is solved numerically for several scenarios.