• The Journal of Engineering Geology
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• v.33 no.4
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• pp.701-716
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• 2023

Microplastics (<5 mm diameter) in aquatic environments adsorb heavy metals, potentially exposing humans to their toxic effects via food chains. We investigated factors influencing the adsorption of heavy metals on microplastics in aquatic environments, examining their adsorption processes and mechanisms. Adsorption characteristics vary with polymer type, crystallinity, particle size, and environmental conditions (pH, temperature, weathering), and the adsorption capacity for heavy metals increases with weathering and reduction in polymer particle size. However, correlations between environment temperature, polymer crystallinity, and adsorption capacity for heavy metals could not be confirmed. The adsorption behavior of heavy metals can be explained in terms of physicochemical adsorption processes and evaluated through adsorption kinetics and isothermal studies, with multiple mechanisms usually being involved. An understanding of the adsorption of heavy metals by microplastics should aid evaluation of the potential risks of microplastics in aquatic environments.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.233-242
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• 2013

Securing the appropriability strategy of R&D funding for technology innovation is very important because R&D needs a lot of time and money. Appropriability means the environmental factors that govern an innovator's ability to capture profits generated by an innovation. Generally appropriability mechanism has five kinds, including patent, secrecy, lead time advantage, complementary sales & service, complementary manufacturing. In this paper, we surveyed domestic software industry professionals about appropriability mechanism strategy, and presented a result of priority of each factor and difference between previous research and this study, using the pair-wise comparison method. The result of study showed that domestic IT manufacturing companies prefer patent better than other appropriability mechanism.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.283-291
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• 2012

The present work reviews some mechanism explaining how thin layer can develop in the near coastal zone. The existence of thin layer was observed by physical research methods later than classical biological approaches. The Richardson number, which is a ratio between the stratification and shear stress is crucial factor determining the occurrence of thin layer. Micro-structure turbulence seems to affect the plankton behavior, in particular the encountering rate. Encountering rate affects significantly feeding, reproduction etc. and this fact was proved by the mechanical simulation methods. Recently the Gyrotaxis was introduced to explain how thin layer occurs in the mixing layer. Such physical approaches to explain ecological problem will be prominent methods for marine ecological research area.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.631-634
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• 2017

앞으로의 프로젝트에서는 시장 변화, 신기술, 경쟁업체의 대응, 설계결함, 테스트 실패 등의 다양한 외부적 요인으로 인해, 더욱 빈번한 요구사항 변경이 요청된다. 그 이전에 명료한 요구사항을 정의하기가 매우 어렵고, 소프트웨어 구축 중에도 수시로 요구사항이 변경되고 있는 실정이다. 이런 문제는 요구사항 추적성 및 변경 관리의 미비함에 있다. 이를 해결하기 위해, 소프트웨어 개발 프로세스인 요구사항, 분석, 설계, 구현, 테스트 단계에서의 추적성 관리를 위한 프로세스의 구축과 내재화가 필요하다. 본 논문에서는 클로즈 아키텍처 메커니즘을 기반으로 소프트웨어 각 개발 단계 산출물들 간의 추적성 매트릭스를 제시한다. 이를 통해 프로젝트 과정에서의 잦은 요구사항 변경에 유연하게 대처함으로써 소프트웨어 품질 향상에 기여 할 것으로 본다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1271-1274
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• 2004

현재 운용중인 대부분의 VPN은 모든 CPE(Customer Premise Equipment) VPN GW(Gateway)들이 Center VPN GW에 연결되어 있는 Star 구조를 취하고 있다. 이러한 구조에서는 모든 트래픽들이 항상 Center VPN GW를 거쳐서 전송되므로 비효율적인 트래픽 전송이 이루어진다. 또한 대용량의 멀티미디어 트래픽 전송이 빈번하거나 다수의 지점을 갖고 있는 기업의 경우 Center VPN GW에서의 오버헤드가 증가하게 된다. 이러한 문제를 해결하기 위한 방법으로는 IPSec의 IKE(Internet Key Exchange) 메커니즘을 이용하여 CPE VPN GW간 직접 터널을 맺어 줄 수 있으나, 터널 설립에 앞서 원격지 CPE VPN GW의 주소, 요구되는 보안 등급 등의 터널 설정에 필요한 정보를 관리자가 직접 설정해 주어야 한다. 이는 현재 DHCP와 같은 동적 IP 환경에서 운용되는 ADSL 기반의 VPN 환경에서 관리 오버헤드를 증가시키는 요인이 된다. 이에 본 논문에서는 CPE VPN GW 간 직접 터널 연결이 필요할 시에 자동적으로 제반 기능들이 수행될 수 있게 하는 주문형 터널 생성(On-demand Tunnel Creation) 메커니즘 제안한다. 시뮬레이션을 통해 제안하는 방안에 대하여 성능을 조사하였고, 이와 함께 기존의 Star VPN 구조, Full-mesh VPN 구조와 성능을 비교하였다. 시뮬레이션 결과, 제안하는 방안이 기존의 Star VPN 구조보다 확장성과 트래픽 전송효율성, Center VPN GW의 오버헤드 측면에서 우수한 성능을 보였으며 Full-mesh 구조의 VPN과 거의 비슷한 종단간 지연시간과 처리율을 보였다.

• Journal of Labour Economics
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• v.28 no.1
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• pp.61-82
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• 2005

We investigate wage differentials in Korea in the manufacturing industry, as well as factors affecting structural change in wage determination for the pre- and post-financial crisis regimes. We use the 1995 and 1999 data from the Survey Report on the Wage Structure (SRWS) from the Ministry of Labor. Principal components regression analysis is used to tackle multicollinearity. We employ factor analysis to reduce a set of variables to a smaller number, which contain observed and latent variables. Our empirical investigation provide evidences for changes in wages structure between 1995 and 1999. In 1995, the job quality factor is the most critical in the determination of wages, while in 1999, the industry attributes factor impacts greatly on the wages.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.131-139
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• 2006

컴퓨터 게임 산업의 급속한 성장에도 불구하고 소수의 게임 타이틀만이 과도한 생산비를 감당하면서 수익을 내고 있는 실정이다. 기존 마케팅 이론 에 의하면 제품의 성공과 실패는 고객의 선호도, 필요, 기대에 대한 만족도 에 의존한다고 한다. 이와 마찬가지로 게임에서도 사용자의 만족을 극대화 하기 위해서는 사용자들이 무엇을 원하고, 좋아할지를 파악하여 이를 게임에 반영할 필요가 있다. 본 연구의 목표는 MMO 게임 디자인을 위한 사용성 평가 핵심 요인을 고찰하는데 있다. 본 연구는 기존의 게임 관련 HCI / 사용성에 대한 문헌 고찰을 통하여 사용성 평가 핵심 요소를 도출하고 게임 플레이 과 제와 사후 설문결과를 통하여 MMO게임 사용성 평가를 실시하여 18가지 사용 성 문제 점과 그 권장사항을 제시하였다. 그 결과 게임 인터페이스, 게임 플 레이, 게임 서사, 게임 메커니즘으로 구성된 54 개의 사용성 평가 핵심 요 소를 도출 하고 MMO 게임을 위한 새로운 사용성 평가 체계를 개발하였다. 본 연구 결과는 MMO게임 디자인 프로세스의 초기 단계에서 효과적인 디자인 의 사결정을 지원하고 게이머의 행동을 이해하는데 중요한 시사점을 제공 할 것 을 기대 된다.

• Korean Journal of Social Welfare
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• v.63 no.2
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• pp.233-260
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• 2011

This study intends to analyze the trend of employment rate of men aged 55~64 in 15 OECD countries from 1980 to 2005. Furthermore, this study means to examine the determinants of men aged 55~64 in 15 OECD countries to support the labor force participation among them. The analysis is based on the data of OECD, ILO and LIS. The analysis method is Arellano and Bond(1981)'s difference GMM which used instrumental variables by dynamic panel model which estimates state dependency of labor market participation and individual panel's heterogeneity. The main results from this analysis are summarized in three points. First, the employment rates of men aged 55~64 had decreased until the middle of the 1990s, while that has been increasing since 1995. Second, the sate dependency strongly worked in the employment rates of 55~64 men and positive period effect was observed for 1980~2005. This study cannot find the pull effect of public pension, while labor market push effect have negatively affected. Third, temporary work rates had contributed to increase the employment rate of men aged 55~64 for 1996~2005. The poverty has become the mechanism of the labor.

• Journal of Korea Technology Innovation Society
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• v.14 no.3
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• pp.405-430
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• 2011

I examine what factors influence a firm's openness to external sources of knowledge in the Korean manufacturing sector. Related literature suggests a firm's appropriability strategy, absorptive capacity, technology entrepreneurship, firm size and industry-level technological opportunities as possible determinants. Using Korean Manufacturing Innovation Survey, I test how these factors influence the degree of openness of Korean manufacturing firm. I find the followings: First, when the appropriability strategy becomes tighter, a firm becomes more open to external sources. Second, when the share of highly educated employees increases, a firm becomes more open. Third, when a firm is a technology entrepreneur, the openness increases. Fourth, a large firm is likely to be more open. Lastly, ample technological opportunities increase the openness. In Korean manufacturing industries, the highly educated employees and technology entrepreneurship are more influential factors for a firm's openness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.79-87
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• 2021

This study suggests a design process for vibrotactile interface that can apply haptic perception factors reflecting human tactile mechanisms. This process consists of 4 stages: the haptic sense requirement analysis stage, the haptic element analysis stage, the haptic perception factor analysis stage, the haptic requirement detailed design, and the prototype implementation stage. The advantage of this design process is that unnecessary tasks can be excluded in deriving and implementing user requirements, by applying haptic perception factor analysis, and the biggest feature is that research results on ergonomic mechanisms can be reflected in the haptic design, completes prototype development simultaneously while determining the haptic requirements statement by performing user evaluation, usability testing, and haptic feature optimization tasks simultaneously. This design process includes all stages from user requirements to haptic function detailed design and prototype implementation, so it is expected that general developers who lack expertise in haptic will also be able to design user-centered designs, enabling design and implementation of haptic functions at a certain level.