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OBJECTIVES: The first confirmed case of coronavirus disease 2019 (COVID-19) in South Korea was reported in January 2020, with 28 confirmed cases reported as of February 14th, 2020. The epidemiological and clinical characteristics of all 28 cases were analyzed in response to this disease. METHODS: The epidemiological characteristics and early clinical features of the 28 patients from Korea with confirmed COVID-19 were analyzed using COVID-19 reporting and surveillance data and the epidemiological investigation reports prepared by the rapid response team. RESULTS: There were 16 patients that entered Korea from foreign countries: Wuhan, China (11 patients), Zhuhai, China, (1 patient), Singapore (2 patients), Japan (1 patient), and Thailand (1 patient). The early symptoms were fever, sore throat, cough or sputum production, chills, and muscle ache. Three patients were asymptomatic, however, 18 developed pneumonia. Of the 28 cases, 16 were index cases imported from abroad, with 10 cases of secondary infection originating in Korea, and the route of transmission still under investigation for 2 patients. The 10 patients with secondary infection were infected from contact with family members or acquaintances of primary patients, and the suspected sites of transmission were mostly at home. CONCLUSION: COVID-19 in Korea was spread by 16 infected individuals traveling from other countries, leading to second-generation cases. The initial symptoms were mostly minor, but the disease was infectious at this stage, resulting from close contact, particularly at home. Establishing an early detection strategy for COVID-19 is crucial for managing the transmission of the disease.

Increased awareness of adverse events following immunization (AEFI) can disrupt vaccination programs. In South Korea, a report of alleged influenza vaccine-related deaths attracted significant media attention in 2020. We retrieved the vaccination coverage and AEFI data to determine their association with media coverage. Between 2015 and 2019, the vaccination coverage rate ranged between 80.5% and 83.3%; however, the vaccination coverage rate declined significantly from 2020 to 2021 to 73.6% (p < 0.0001). During the 43rd week of 2020, following a large amount of media coverage on vaccine safety issues, the number of cases with AEFI reached 60. Between 2015 and 2020, the mortality rate ratios for influenza vaccines and non-vaccines ranged between 0.1296 (95% confidence interval (CI), 0.1262–0.1331, p < 0.0001) and 0.1608 (95% CI, 0.1572–0.1644, p < 0.0001). Vaccine safety surveillance should be continued in conjunction with investigation and transparent risk communication to maintain public trust in vaccines and vaccinations.

Identifying the factors of emotional experience that arouse emotional responses will contribute to determining the relationship between the visual attributes of a salon and the emotional responses of humans, as well as the relationship between service factors and the emotional response of humans. The aim of this study is to examine the effect of the various e motional responses of customers on store preference and to thereby propose marketing strategies for offering an insightful service. The emotionally expressed vocabulary used by customers during their visit is also explored. 300 customers with previous experience of beaut y shop services were surveyed and their responses were analyzed using SPSS 20.0 to define the problems. All the emotional experiences at the beauty salon influence the service satisfaction and re-visitation intention. The results showed that, as the customer`s level of satisfaction with a service experience increases, the re-visitation intention increases. Of these results, only the service experience influences the recommendation intention. As the effective delivery of positive emotional services influences customers` revisiting intentions, beauty industry workers should be aware of each phase of the customers` emotions and try to provide customer-oriented services to appease these emotions. In addition, workers should strive to create service systems that induce customers` positive emotional responses rather than to offer merely stereotyped services.

A common-mode (CM) active filter was designed in a compact package to suppress CM conducted emissions at a switching mode power supply (SMPS). Based on the analytical expressions considering both stability and performance, the design and optimization rules for the proposed active filter have been presented. After verifying its performance by measurements using vector network analysis, the proposed filter was installed in a 200-W SMPS board with 64 and 110 kHz switching frequencies, demonstrating its usefulness by experiments. The performance degradation due to the magnetic saturation and the AEF grounding impedance was also analyzed and investigated.

This paper describes the application of a passive noise cancellation method to a prototype inductor-inductor-capacitor (LLC) resonant converter by placing a compensation winding in a transformer to reduce common mode noise. The connection method for the compensation winding is investigated. A circuit analysis is implemented for the displacement currents between the primary and secondary windings in the transformer. The analyzed displacement currents are verified by performing a circuit simulation and a proper compensation winding connection that reduces common mode noise is found. The measurement results show that common mode noise is reduced effectively up to 20 dB in the 1 to 7 MHz frequency region for the prototype LLC resonant converter by using the proposed passive noise cancellation method.

In this work, we studied the microstructural changes of ITO during the annealing process. ITO nanoparticles were prepared by the sol-gel method using indium tin hydroxide as the precursor. The prepared sample was investigated using TEM, powder XRD, XPS, DRIFT, and 2D correlation analysis. The O 1s XPS spectra suggested that the microstructural changes during the annealing process are closely correlated with the oxygen sites of the ITO nanoparticles. The temperature-dependent in situ DRIFT spectra suggested that In-OH in the terminal sites is firstly decomposed and, then, Sn-O-Sn is produced in the ITO nanoparticles during the thermal annealing process. Based on the 2D correlation analysis, we deduced the following sequence of events: 1483 (due to In-OH bending mode) → 2268, 2164 (due to In-OH stretching mode) → 1546 (due to overtones of SnO-Sn modes) → 1412 (due to overtones of Sn-O-Sn modes) cm �1 .

An equivalent dipole model is proposed in this paper to represent the source of radiated electromagnetic emissions from an integrated circuit (IC). The height of an IC is usually much smaller than its length and width, so only three dipole moments are sufficient to characterize an IC in terms of its electromagnetic emissions. The dipole moments can be extracted from three TEM cell measurements. The radiated fields from the IC can then be calculated based on the extracted dipole sources. This IC emission model with three dipole moments is validated using the far-field measurements in a semi anechoic chamber for a test IC. For complex structures, it is desirable that the extracted dipole moments can be incorporated into a commercial full-wave tool as equivalent sources to simulate the radiations from an IC. This is demonstrated using an approach developed in this paper.

TEM cells or GTEM cells can be used to evaluate the radiated emissions of integrated circuits (ICs). The applicable frequency bandwidth of a TEM cell is limited due to the resonances of higher order modes. This paper describes how a TEM cell can be modified to extend the frequency range without changing the test topology. Several methods are proposed and implemented to suppress the higher order modes. The magnetic field coupling and electric field coupling are evaluated for the new design. The frequency bandwidth of the modified TEM cell is extended from original 1 GHz to 2. 5 GHz.

Case-based reasoning (CBR) is a method for solving new problem similar with it using the past solving problem experience. A case can be seen as a complex object that contains at least a problem description and a solution (i.e., a conditionally and a consequence). Between the conditionality and its consequence a strong association is existed. The focus of this paper is to describe a method discovering usable rules among case history by using the generalized association rule algorithm. Emphasis placed on approaching association rule mining for discovering rules existing in case history.

We report a novel, yet simple, method for the preparation of high aspect ratio cylindrical microdomains oriented vertically on a substrate by using block copolymer micelles and temperature-programmed solvent vapor annealing. Multilayered spherical micelles were first prepared by spin-coating of polystyrene-block-poly(4-vinylpyridine) copolymer (PS-b-P4VP) in toluene solution on a silicon wafer. When temperature-programmed solvent vapor annealing was performed, the spherical micelle cores consisting of P4VP chains were transformed into vertically oriented cylindrical microdomains spanning the entire film thickness up to 550 nm corresponding to the aspect ratio of 15.2. Since nitrogen in the P4VP block could be easily coordinated with many metal precursors, we also fabricated a high density array of gold nanoparticle/polymer nanocomposite nanorods oriented vertically on the substrate.