• Safety and Health at Work
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• 제4권2호
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• pp.111-116
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• 2013

Background: The aim of this study was to evaluate the quality of the Second Korean Working Conditions Survey (KWCS), focusing on its validity and reliability. Methods: The external validity was evaluated by the assessment of sampling procedures and the response rate, in order to investigate the representativeness of the sample. The content validity was evaluated by the assessment of the development of the questionnaire, and the consistency of questions for the selected construct. The test-retest method was used to evaluate the reliability by means of a phone call survey of 30% of the respondents, who were randomly selected. The respondents' satisfaction regarding the survey procedures and interview time were analyzed to evaluate the quality of survey data. Results: The external validity was assured by an acceptable sampling procedure, rigid multi-stage stratified cluster random sampling. The content validity was also guaranteed by a reasonable procedure for the development of the questionnaire with a pretest. The internal consistency of the questions for work autonomy was maintained, with 0.738 of Cronbach's alpha. The response rate of 36% was lower than that of the European Working Conditions Survey (EWCS), with a contact rate of 66%, compared to 76% for the EWCS. The matching rates of the five retested questions were more than 98% reliable. Conclusion: The quality of the second KWCS was assured by the high external and content validity and reliability. The rigid sampling procedure and development of the questionnaire contributed to quality assurance. The high level of reliability may be guaranteed by the sophisticated field survey procedures and the development of a technical manual for interviewers. The technical strategies for a high response rate should be developed for future surveys.

• Journal of Veterinary Science
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• 제21권4호
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• pp.57.1-57.11
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• 2020

Background: Streptococcus dysgalactiae subspecies equisimilis (SDSE) acts as an etiological agent for lameness, neurological signs, and high mortality in pigs. Despite its importance in pig industries and zoonotic potential, little is known about the effects of this pathogen. Objectives: This study aimed to determine the molecular characteristics and antimicrobial resistance of SDSE strains isolated from diseased pigs. Methods: A total 11 SDSE isolates were obtained from diseased pigs. Bacterial identification, PCR for virulence genes, emm typing, and antimicrobial resistance genes, multilocus sequence typing, and antimicrobial susceptibility test were performed. Results: Nine isolates were from piglets, and 8 showed lameness, sudden death, or neurological signs. The isolates were PCR-positive for sla (100%), sagA (100%), and scpA (45.5%), and only 1 isolate amplified the emm gene (stL2764). Eight different sequence types were detected, categorized into 2 clonal complexes and 4 singletons. All the isolates in this study were included in a small cluster, which also contained other strains derived from humans and horses. The minimum inhibitory concentrations for the tested beta-lactams were low, while those for macrolides, tetracyclines, and fluoroquinolones were relatively high. PCR analysis of the macrolide and tetracycline resistance genes demonstrated that the isolates carried erm(B) (18.2%, n = 2), mef(A/E) (9.1%, n = 1), tet(M) (18.2%, n = 2), and tet(O) (90.2%, n = 10). Two isolates presented a mutation in parC, which is associated with fluoroquinolone resistance. Conclusion: This study provided insight into swine-derived SDSE, as it is related to veterinary medicine, and elucidated its zoonotic potential, in the context of molecular epidemiology and antimicrobial resistance in public health.

• 만화애니메이션 연구
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• 통권9호
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• pp.59-79
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• 2005

이 논문은 지방문화산업지원센터의 역할모델을 중심으로 산 ${\cdot}$학 협력을 기반으로한 지역문화콘텐츠산업의 혁신 환경을 창출하기 위한 사업모델을 개발하는데 초점을 두었다. 이를 위하여 경기디지털콘텐츠진흥원의 공공아카데미사업과 경기문화원형디지털콘텐츠개발 사업에 대한 사례분석을 실시하였다. 이를 바탕으로 이 논문에서는 지역문화산업 혁신환경 차원에서 경기디지털콘텐츠진릉원의 산학협력사업 모델을 문화콘텐츠 R&D 네트워크센터 구축사업, 인력양성사업과 지역클러스터사업의 연계 강화사업, 산 ${\cdot}$ 학과의 파트너쉽 기반 문화콘텐츠체험 및 학습 프로그램 체계 구축사업 등 세 가지 차원에서 설정하였다.

• 한국전자파학회논문지
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• 제27권6호
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• pp.545-556
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• 2016

JPDAF(Joint Probabilistic Data Association Filter)는 다중표적 추적에서 존재하는 표적에서 측정값들이 유래되었을 사후 확률을 이용하여 표적의 상태 추정치에 대한 갱신을 진행하는 방식이다. 이러한 JPDAF 방식에 고정구간 평활화(fixed-interval smoothing)기법을 적용하여 얻은 JPDAS(Joint Probabilistic Data Association Smoothing) 방식을 기반으로 이 논문에서는 모탄에서 분리되어 낙하하는 다수의 자탄에 대한 다중표적 추적알고리즘을 제안하였다. 독립적으로 JPDAF와 JPDAS를 이용한 다중표적 추적알고리즘을 100번 수행하여 얻은 표적의 상태 추정치와 표적의 실제 상태의 차이의 평균으로 두 다중표적 추적알고리즘의 성능을 비교하였다. 이를 기반으로, 제안한 JPDAS가 JPDAF보다 레이다의 표적 추적 문제에 대한 성능이 좋음을 보여주는 시뮬레이션 결과들이 제시되었다.

• 한국재료학회지
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• 제27권5호
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• pp.276-280
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• 2017

This study was carried out to evaluate the developed microstructures and mechanical properties of friction welded A6063 alloy. For this work, specimens were prepared at a size of 12 mm ${\O}{\times}80mm$, and friction welding was carried out at a rotation speed of 2,000 RPM, friction pressure of $12kgf/cm^2$ and upset pressure of $25kgf/cm^2$. To perform an analysis of the grain boundary characteristic distributions, such as the grain size, orientation and misorientation angle distributions, the electron back-scattering diffraction method was used. In addition, in order to identify the dispersed intermetallic compounds of the base and welded materials, transmission electron microscopy was used. The experimental results found that the application of friction welding on A6063 led to significant grain refinement of the welded zone relative to that of the base material. Besides this, intermetallic compounds such as AlMnSi and $Al_2Cu$ were found to be dispersed with more refined size relative to that of the base material. This formation retains the mechanical properties of the welds, which results in the fracture aspect at the base material zone. Therefore, based on the developed microstructures and mechanical properties, the application of friction welding on A6063 could be used to obtain a sound weld zone.

• Pediatric Infection and Vaccine
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• 제31권1호
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• pp.102-112
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• 2024

목적: 우리나라 강원도 내 어린이집, 유치원, 초중고(공교육) 교육시설과 사교육시설을 포함한 교육시설 관련 COVID-19 감염병 집단사례의 역학적 특성과 위험요인을 파악하고자 한다. 방법: 연구기간은 2020년 12월 10일부터 2021년 9월 23일까지 질병관리청 질병보건통합관리시스템에 신고된 강원도 내 코로나19 확진자 5,318명 중 교육시설 관련 집단감염으로 분류된 19개의 교육시설 관련 확진자 407명을 대상으로 조사하였다. 결과: 교육시설 관련 확진자는 19개의 교육시설 총 407명으로 19세 이하는 204명(50.1%) 이었다. 선행 전파자는 가족이 155명(38.1%), 교사125명(30.7%)이었다. 이차감염자가 확진자로부터 노출된 장소는 집이 139명(34.2%)으로 가장 높았다. 총 19개 집단에서 9개 집단의 근원 환자(추정)는 교사로 확인되었다. 교사가 선행 감염원인 경우의 평균 발병률(2.4%)이 학생이 근원 환자(추정)인 집단의 평균 발병률(1.5%)보다 높았다. 또한 교육시설 내 위험도 종합평가 점수가 높은 사교육시설에서 발병률과 2차 발병률이 높았다. 결론: 본 연구에서 교육시설보다는 가정에서의 전파가 더 큰 것이 확인되었고, 교육시설 내 위험도 종합평가점수가 높은 교육시설에서는 교내 발병률이 가정내 발병률보다 높았고, 공교육 시설보다 사교육시설의 위험도 점수가 높은 곳이 많았으며, 교사들이 근원 환자(추정)인 사례가 많았다. 이러한 결과를 근거로 학생들과 더불어 교사들의 방역 수칙 이행에 대한 감시의 강화가 필요하겠다. 또한 지속적인 교육 당국의 모니터링을 통해 감염병 범유행 상황에서 감염으로부터 안전한 환경에서 교육이 이행될 수 있도록 지속적으로 노력해야 할 필요가 있다.

• 한국수산과학회지
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• 제54권3호
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• pp.329-339
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• 2021

The monthly variation in species composition of fishes in the Gujora and Mangchi coastal waters in Geoje, Korea, was investigated between June 2018 and May 2019 through monthly fish collections using a gill net. A total of 46 species, numbering 410 individuals weighing a total of 96,645.0 g, were collected during the study period. The dominant species in terms of numbers were Chelidonichthys spinosus, Stephanolepis cirrhifer, Ditrema temmincki, Sillago japonica, Sebastes inermis, and Paraplagusia japonica. The number and biomass of fishes peaked in July. The peak in species diversity indices occurred in September. The cluster analysis revealed that there were four groups of fishes depending on the season. In addition, subtropical fishes were recorded in the study area, indicating the gradual subtropicalization of the coast of Geoje. Furthermore, the need to understand the changes in marine ecosystems owing to subtropicalization through continuous monitoring is emphasized.

• Safety and Health at Work
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• 제8권4호
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• pp.393-397
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• 2017

Background: It has been suggested that engaging technology can empower individuals to be more proactive about their health and reduce their health risks. The aim of the present intervention was to study the effects of technology-aided testing and feedback on physical activity and biological age of employees in a middle-sized enterprise. Methods: In all, 121 employees (mean age $42{\pm}10$ years) participated in the 12-month three-arm cluster randomized trial. The fitness measurement process (Body Age) determined the participants' biological age in years. Physical activity was measured with the International Physical Activity Questionnaire Short Form. Results: Physical activity did not change during the intervention. Biological age (better fitness) improved in all groups statistically significantly (p < 0.001), but with no interaction effects. The mean changes (years) in the groups were -2.20 for the controls, e2.83 for the group receiving their biological age and feedback, and -2.31 for the group receiving their biological age, feedback, and a training computer. Conclusion: Technology-aided testing with feedback does not seem to change the amount of physical activity but may enhance physical fitness measured by biological age.

• 산업경영시스템학회지
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• 제46권4호
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• pp.160-172
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• 2023

In contemporary global warfare, the significance and imperative of air transportation have been steadily growing. The Republic of Korea Air Force currently operates only light and medium-sized military cargo planes, but does not have a heavy one. The current air transportation capability is limited to meet various present and future air transport needs due to lack of performance such as payload, range, cruise speed and altitude. The problem of population cliffs and lack of airplane parking space must also be addressed. These problems can be solved through the introduction of heavy cargo planes. Until now, most studies on the need of heavy cargo plane and increasing air transport capability have focused on the necessity. Some of them suggested specific quantity and model but have not provided scientific evidence. In this study, the appropriate ratio of heavy cargo plane suitable for the Korea's national power was calculated using principal component analysis and cluster analysis. In addition, an optimization model was established to maximize air transport capability considering realistic constraints. Finally we analyze the results of optimization model and compare two alternatives for force structure.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.159-164
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• 2024

Net surplus serves as a crucial indicator of how efficiently local governments utilize their resources. This study aims to analyze and categorize the patterns of net surplus across 75 local governments in Korea. By employing machine learning techniques such as K-means clustering and silhouette analysis, this research delves into surplus patterns, revealing insights that differ from those provided by traditional analytical methods. Machine learning enables a broader spectrum of discoveries, leading us to identify three distinct clusters in the net surplus of Korean local finances. The characteristics of these three clusters show that the wealthiest cities have the highest surplus ratios. In contrast, mid-sized municipalities, constrained by limited central government support and scarce local resources, exhibit the lowest surplus ratios. Interestingly, a significant number of cities maintain a median surplus ratio even under challenging fiscal conditions. Additionally, we identify critical thresholds that differentiate the three clusters: a grant-in-aid ratio of 19.31%, a debt ratio of 3.52%, and a local tax ratio of 25.58%. This identification of thresholds is a key contribution of our study, as these specific thresholds have not been previously addressed in the literature.