• 한국자동차공학회논문집
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• 제19권2호
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• pp.98-104
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• 2011

The introduction of a diesel engine into the passenger car and light duty applications in the United States involves significant technical challenges for the automotive makers. This paper describes the SCR System optimization procedure for such a diesel engine application to meet Tier2 Bin5 emission regulation. A urea SCR system, a representative $NO_x$ reduction after-treatment technique, is applied to a 3.0 liter diesel engine. To achieve the maximum $NO_x$ reduction performance, the exhaust system layout was optimized using series of the computational fluid dynamics and the urea distribution uniformity test. Furthermore a comprehensive simulation model for the key factors influencing $NO_x$ reduction performance was developed and embedded in the Simulink/Matlab environment. This model was then applied to the urea SCR system and played a key role to shorten the time needed for SCR control parameter calibration. The potential of a urea SCR system for reducing diesel $NO_x$ emission is shown for FTP75 and US06 emission standard test cycle.

• 한국안전학회지
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• 제34권5호
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• pp.153-158
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• 2019

It is estimated that about 2,515 persons have been injured by conveyor for the past five years(2013 ~ 2017). Conveyors used in various industrial sites for transporting iron ore, coal, courier goods, etc., have various incidents such as a worker putting on or pulling a part of the body or work clothes on the driving part during maintenance. It is necessary for preventing similar accidents to conduct various researches. In order to propose the basis for revising laws and standards for the safety standards of the full cord switch to prevent conveyor accidents, this study compares Korea's Industrial Safety and Health Law (KISHL) with those of IEC, EN, Canada, and Australia. In addition, surveys of conveyor use plant and full cord switch domestic and foreign manufacturers was conducted. In this study, domestic and overseas related laws and technical standards compare and analyze to prevent conveyor accidents. In addition, we propose extension of safety certification for full code switch, establishment of safety inspection standard, and improvement of working method regulation through actual working condition investigation. It can be used as a basis for revising the occupational safety and health regulation and related notices, and thus contributing to enhancing the safe atmosphere of the conveyor business and improving the safety consciousness of the concerned persons.

• 한국건설관리학회논문집
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• 제12권5호
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• pp.103-116
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• 2011

도로변 크랙실링 공법은 도로면에 발생된 크랙을 초기에 효과적으로 보수함으로써 후속 크랙 방지 및 동결피해를 방지하고 도로 하부 구조를 보호하여 도로의 평균상태지수를 높일 수 있는 예방적 유지보수 공법이다. 그러나 재래식 도로면 크랙실링 공법은 작업의 특성상 교통량이 많은 대도시나 고속도로에서 대부분의 작업이 수행되므로 작업 노무자의 안전성을 확보하기 어렵고, 숙련공의 부족으로 인해 작업 생산성 및 품질이 저하되는 등 문제점을 지니고 있다. 1990년대 초반부터 북미 등 선진 외국에서는 재래식 도로변 크랙실링 공법을 자동화하기 위한 연구를 지속적으로 수행하고 있으며 국내에서도 2001년부터 2004년까지 도로면 크랙실링 자동화 장비를 개발하고 현장 실험을 수행한 바 있으나, 작업 품질, 제어의 복잡성, 고가의 장비 구입 가격 등은 개발 장비를 실용화함에 있어 문제점으로 지적되어 왔다. 따라서 본 연구에서는 재래식 크랙실링 공법 및 국내외에서 연구 개발된 도로면 크랙실링 자동화 장비의 문제점을 해결하고 국내 도로 상황과 규정에 부합되는 도로면 크랙실링 자동화 장비의 최적 개념 디자인을 제안하고 원척의(Full-scale) 장비 개발을 위한 제안 기술의 타당성을 분석하였다.

• 방사성폐기물학회지
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• 제7권3호
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• pp.183-190
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• 2009

고준위폐기물 처분장의 기본적인 기능은 단기간에 과도한 방사성핵종이 유출되는 것을 방지하는데 있다. 이를 위해서는, 처분시스템의 구성요소들과 관련된 많은 기술 기준이 개발되고 수립되어야 한다. 처분장 안전성평가는 합리적으로 단순화된 모델에 바탕을 두고 처분장의 미래 전개에 대한 정량적인 결과를 산출하므로 안전성평가는 기술기준의 하나로 간주되고 있다. 본문에서는 평가기간, 선량 제한치 및 평가의 불확실성 등을 중심으로 안전성평가와 관련된 주요국의 기술기준을 조사하였다. 특히, 미국의 기준을 조사하는 과정에서 안전성평가에서 도출된 peak dose가 선량 제한치를 충족하지 못하는 경우, 평가기간 및 peak dose에 대한 미국 규제당국의 접근방안은 참고할만한 가치가 있음을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.612-620
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• 2022

Recent studies have revealed that probiotics and their metabolites are present under various conditions; however, the role of probiotic metabolites (i.e., postbiotics in pathological states) is controversial. Natural killer (NK) cells play a key role in innate and adaptive immunity. In this study, we examined NK cell activation influenced by a postbiotics mixture in response to gut microbiome modulation in stress-induced mice. In vivo activation of NK cells increased in the postbiotics mixture treatment group in accordance with Th1/Th2 expression level. Meanwhile, the Red Ginseng treatment group, a reference group, showed very little expression of NK cell activation. Moreover, the postbiotics mixture treatment group in particular changed the gut microbiome composition. Although the exact role of the postbiotics mixture in regulating the immune system of stress-induced mice remains unclear, the postbiotics mixture-induced NK cell activation might have affected gut microbiome modulation.

• Journal of Korea Trade
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• 제25권6호
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• pp.105-125
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• 2021

Purpose - This study analyzes the effects that the response to the technical barriers to trade (TBT), which are used by various countries as means to restrict imports, exerts on exports at a time when protectionism is emerging in the face of a global economic downturn. TBT has been widely used in developed countries for the safety and protection of their people. Recently, the use of TBT as a tool of protectionism has increased considerably in developing countries as well. Therefore, this study analyzes the South Korean SMEs' response and export performance. Design/methodology - To analyze SMEs' response to TBT and their export performance, this study conducted empirical analysis through statistical analysis. To this end, the research established a theory based on previous research and designed its hypothesis and research model. To verify the hypothesis and research model, factor analysis addressing validity and reliability was performed using SPSS 25 and AMOS 26, and the structural equation model was analyzed. Findings - This study found the causal relationship between the independent variable, the mediating variable, and the dependent variable adopted against the theoretical background to have little or no effect, in contrast with previous studies. In a break from previous studies, all hypotheses were rejected for innovation strategic competencies, one of the sub-factors of the independent variable, which is believed to be a result of the lack of practical research related to TBT. Originality/value - Previous studies performed analysis using trade statistics or macro data. A number of such studies analyzed the relationship between technical regulation and trade volume. This study differs from previous studies in some respects, because it analyzed the export performance of companies by establishing a hypothesis and implementing a research model with the factors analyzed in previous studies. In addition, a new attempt has been made by classifying the TBT response factors into technology competencies, human resource competencies, and innovation strategic competencies, and utilizing technology innovation and the export support system as mediating effects.

• 자동차안전학회지
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• 제9권3호
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• pp.13-18
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• 2017

Since 2015, Euro-NCAP and C-NCAP have enhanced regulation on submarine of rear female passenger. This submarine regulation is a big obstacle to achieve the highest level crash performance. So the objective of this study is to develop new technical way to protect rear female passenger against submarine. In this study, we figured out how design factors of seatbelt affect submarine of rear female passenger by sled test. And we verified that rear passenger submarine can be improved by increasing intersection angle of seatbelt anchor and rotation amount of seatbelt buckle. Based on these results, this paper proposes a new invention of seatbelt buckle and anchor that can improve rear passenger submarine. One is seatbelt buckle that can be detached from stopper to prevent rotation and the other is seatbelt anchor that can be changed the structure so as to incline forward during crash. Finally we proved that submarine of rear female passenger can be improved by the effectiveness of new inventions.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.22-27
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• 2006

As the regulation and assessment program for safety of passengers become stringent, automakers are required to develop lighter and safer vehicles. In order to fulfill both requirements which conflict with each other, automobile and steel companies have proposed the application of AHSS(Advance High Strength Steel) such as DP, TRIP and martensite steel. ULSAB-AVC model is one of the most remarkable reactions to offer solutions with the use of steel for the challenge to improve simultaneously the fuel efficiency, passenger safety, vehicle performance and affordability. This paper is concerned with the crash analysis of ULSAB-AVC model according to the US-SINCAP in order to compare the effectiveness between the model with AHSS and that with conventional steels. The crashworthiness is investigated by comparing the deformed shape of the cabin room, the energy absorption characteristics and the intrusion velocity of a car.

• 한국보육지원학회지
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• 제19권1호
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• pp.43-67
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• 2023

Objective: This study aimed to validate a scale which could measure the correct mediation behavior of parents for their children's smart media use. Methods: The subjects were comprised of 514 parents of 5-year-old children. The collected data were analyzed using Jasp. Results: First, in the primary validation process, a total of 19 items and five factors were extracted through exploratory factor analysis. Through secondary validation process, we found that the scale model satisfies the goodness-of-fit evaluation criteria and is valid through confirmatory factor analysis. The newly constructed parents smart media mediation scale in early childhood emerged as a valid and reliable scale. Second, it was found that the more parents pursue 'active mediation', 'instructive mediation', and 'supervision', and avoid 'co-viewing', and 'technical restrictions', the more they had a positive effect on children's smart media usage capabilities. Third, the total score of smart media mediation for young children's parents was found to significantly differentiate young children's smart media overdependence, and self-regulation. Conclusion/Implications: The final smart media mediation scale for young children's parents was composed of 19 items, with five factors: 'co-viewing', 'instructive mediation', 'technical restrictions', 'active mediation', and 'supervision'.

• 펄프종이기술
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• 제44권2호
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• pp.49-57
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• 2012

The reduction of greenhouse gas emission currently becomes more urgent task for Korean Industries, especially for the paper industries because of the new regulation based on the low carbon-green growth law. In order to reduce effectively the greenhouse gas emission, the development of greenhouse gas emission inventory has been widely considered as one of the basic processes and has been applied to many industries. In this study, the fundamental schemes and the cases of greenhouse gas inventories were investigated. Especially, the major considering units for paper industries were suggested to develope greenhouse emission inventory of paper industry.