• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1190-1199
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• 2014

As a considerable, experimental approach, an autocarriage type of $CO_2$ welding machine and a MIG(metal inert gas) welding robot in the inert gas atmosphere were utilized in order to realize Al 5083 welding to hull and relevant components of green leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc.) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, nonferrous material, applied to manufacturing of eco-environmental leisure ships. With respect to welding condition to minimize the thermal deformation, 150 A and 16 V at the wire-feed rate of 6 mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(heat affected zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5 mm thickness, 284.62 MPa of tensile strength and 11.41 % of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification (WPS).

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.84-84
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• 2009

파이프라인을 건설함에 있어 가장 중요한 기술이 배관 용접기술이다. 즉 파이프와 파이프를 연결하는 작업이 공사 진척도를 결정하기 때문에, 이를 얼마나 경제적으로 신속하게 수행해 나가느냐하는 것은 건설기간 및 건설비용을 결정하는 핵심 요소이다. 가스배관 시공 원주용접 방법은 여러 가지 있는데, 현재 국내에서는 전량 수동용접을 채택하고 있다. 이 방법은 국내 가스배관을 건설한 초기부터 적용해온 것으로 우수한 품질을 확보할 수 있으며, 취약한 국내 자동화기술과 열악한 도로 매설 시공여건에서 적용하기 용이한 방안이다. 그러나 우수한 용접기량을 보유한 용접사가 점차 부족해지고, 배관시공 시간을 단축하고 비용을 줄이기 위한 필요성이 점차 커지면서 이를 해결할 수 있는 기술로서 자동원주용접방안이 있다. 이 기술들은 해외 가스배관에 이미 오래전부터 적용되어 용접부위 신뢰성과 품질 우수성을 확보하고 시공비용절감을 달성하고 있다. 자동용접을 적용하기 위해서는 용접절차를 수립하여 절차인증시험을 수행하고, 기존방안과 동일이상의 품질이 확보되며 효율성을 겸비해야만 한다. 국가 기본에너지의 안정적인 공급을 위해 적기 시공이 필요하고, 1 km당 10 억원 이상이 소요되는 배관시공비용 중 약 1/3이 용접비파괴검사 비용인 점을 감안할 때 품질이 확보되면서 경제적인 시공방안이 있다면 이를 적용하는 것이 국가 산업 경제적 측면에서 필요한 일이다. 이와 관련된 연구에서는 국내 가스배관 원주용접에 적용 가능한 용접공정을 검토하고, 용접절차를 수립하여 절차인증시험을 수행하였으며, 추가로 배관 원주 자동용접부위에 대한 기계적 특성 평가를 실시하였다. 현재 국내 건설여건과 비파괴검사 기준을 만족시키고 안전성과 효율성을 겸비한 방법으로는 초층과 2층은 수동 GTAW를 적용하고 나머지 층은 반자동 FCAW를 적용하는 방안이 적절한 것으로 판단된다. 전 층을 자동 GTAW로 용접하는 방안은 품질은 확보되지만 효율성측면에서 대형배관에는 적용하기 어려울 것으로 보이며, 해외에서 많이 사용되는 자동 GMAW 방안은 국내 비파괴검사기준을 만족시키기 어려워 검토대상에서 제외하였다. 본 논문에서는 두 가지 용접방법에 대한 용접공정개발과정과 원주용접부위 기계적 특성을 검토하여 최적방안을 제시하고자 한다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2006.06a
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• pp.57-62
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• 2006

휴대용 단말기의 소형화 및 지능화와 더불어 차세대 PC 기반의 유비쿼터스 컴퓨팅에 대한 관심이 높아짐에 따라 최근에는 펜이나 음성 입력 멀티미디어 등 여러 가지 대화 모드를 구비한 멀티 모달 상호작용 (Multi-Modal Interaction MMI)에 대한 연구가 활발히 진행되고 있다. 따라서, 본 논문에서는 잡음 환경에서의 명확한 의사 전달 및 휴대용 단말기에서의 음성-제스처 통합 인식을 위한 인터페이스의 연구를 목적으로 Voice-XML과 Wearable Personal Station(WPS) 기반의 음성 및 내장형 수화 인식기를 통합한 멀티 모달 명령어 인식 시스템 (Multi-Modal Instruction Recognition System : MMIRS)을 제안하고 구현한다. 제안되어진 MMIRS는 한국 표준 수화 (The Korean Standard Sign Language : KSSL)에 상응하는 문장 및 단어 단위의 명령어 인식 모델에 대하여 음성뿐만 아니라 화자의 수화제스처 명령어를 함께 인식하고 사용함에 따라 잡음 환경에서도 규정된 명령어 모델에 대한 인식 성능의 향상을 기대할 수 있다. MMIRS의 인식 성능을 평가하기 위하여, 15인의 피험자가 62개의 문장형 인식 모델과 104개의 단어인식 모델에 대하여 음성과 수화 제스처를 연속적으로 표현하고, 이를 인식함에 있어 개별 명령어 인식기 및 MMIRS의 평균 인식율을 비교하고 분석하였으며 MMIRS는 문장형 명령어 인식모델에 대하여 잡음환경에서는 93.45%, 비잡음환경에서는 95.26%의 평균 인식율을 나타내었다.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.29-36
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• 2014

Recently, in order to enhance the function and usefulness of products, cladding of dissimilar materials that maximizes the performance of the material is being widely used in all areas of industry as an important process. Clad steel plate, produced by cladding stainless steel plate, an anticorrosive material, on carbon steel plate, is being used to produce pressure vessels. Stainless steel plate has good corrosion resistance, and carbon steel plate has good rigidity and strength; clad steel can satisfy all of these qualities at once. This study aims to find the ${\delta}$-ferrite behavior, mechanical properties, structure change, integrity and reliability of clad steel weld on hot rolled steel plates. For this purpose, multi-layer welding, repair welding and post weld heat treatment were implemented according to welding procedure specifications (WPS). In order to observe the mechanical properties and toughness of clad steel weld zone, post weld heat treatment was carried out according to ASME Sec. VIII Div.1 UW-40 procedure for post weld heat treatment. With heat treatment at $625^{\circ}C$, the hold time was used as the process variable, increased by intervals that were doubled each time, from 80 to 1,280 min. The structure of weld part was typical cast structure; localized primary austenite areas appeared near central vermicular ferrite and fusion line. The heat affected zone showed rough austenite structure created by the weld heat input. Due to annealing effects of heat treatment, the mechanical properties (tensile strength, hardness, impact value) of the heat affected area tended to decrease. From the results of this study, it is possible to conclude the integrity of clad steel welds is not affected much in field welding, repair welding, multi-layer welding, post weld heat treatment, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.390-396
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• 2015

The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalizations of LBS is the accurate estimating position for mobile object. Focusing on an image sensor deployed in smart phone, we develop a LED based positioning estimation framework. The developed approaches can strengthen the advantages of independent indoor applicability of LED. The estimation of LED based positioning is effectively applied to any indoor environment. We put a focus especially on the algorithmic framework. of image processing of smart phone. From LED lighting, we can obtain a typical signal image which contains the unique positioning information. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.102-102
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• 2015

최근 중소규모 하천은 하천수 및 하천변 지하수 이용의 증가와 토지이용변화 등 유역 내 수문인자의 특성 변화로 인해 하천의 건천화가 점증하고 있어 하천 환경이 악화되고 있는 실정이다. 본 연구에서는 격자기반의 분포형 장기수문 모델(PGA-CC)을 이용하여 과거 수십년동안 토지이용변화에 따른 하천 건천화 영향을 평가하였다. 실제 건천화가 진행되고 있는 삽교천 상류유역($358.8km^2$)을 선정하였고 토지이용변화분석을 위해 과거 1975년 토지이용도(Past), 현재 2008년 토지이용도(Present)를 구축하였다. 각각의 토지이용 항목 중 변화율이 가장 높은 도시비율은 과거 토지이용도에서는 2.6 %였으며 현재 토지이용도에서는 11.3 %로 8.7 %가 증가하였다. 모델 검보정은 최근 7년(2005-2011)동안 최종유역출구지점에서 유출 검보정을 실시하였다. 그 결과 NSE (Nash-Sutcliffe model efficiency)은 평균 0.71로 유출량의 모의값과 실측값이 유효한 것으로 나타났다. 건천화를 평가하기 위해 시험유역에서의 5 WPs (Watching Points)를 선정하여 과거 및 현재 토지이용조건을 모의하고 유황분석을 통한 갈수 변화량 분석을 실시하였다. 건천화 빈도분석을 위해 GEV (Generalized Extreme Value) 갈수빈도분석을 실시하여 과거 토지이용 모의결과 산정된 평균 갈수량($m^3/s$) 이하로 낮아지는 유출량 일수를 계산하였다. 최종유역출구에서 과거 및 현재 토지이용도에서 모의된 평균갈수량은 각각 $3.27m^3/s$ 및 $3.11m^3/s$로 나타났다. GEV 갈수빈도분석결과 과거 토지이용조건에서의 평균갈수량은 $3.20m^3/s$(재현기간 2.33년)으로 나타났다. 도시증가에 따른 인구증가는 지하수 사용량에 증가를 가져온다. 이는, 건천화에 영향을 미치며 본 연구에서는 지하수이용량 자료(1998-2011)를 이용하여 도시면적과 지하수이용량의 선형회귀분석을 실시하여 과거 22년 지하수 사용량을 예측하였다. 그 결과 지하수사용량 증가는 토지이용변화와 복합적으로 상류유역에 하천의 변화를 가속시키는 것으로 나타냈다.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.21-26
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• 2019

This paper examines effect of fitness between innovation and HRM type on firm performance(quality competitiveness, operating profit). Data were extracted from the Korea Labor Institute's workplace panel survey(WPS) from 2015, and the analysis used 3,431 companies. To test the research model, analysis of variance(ANOVA). The model shows that full-innovation/commitment HRM type companies were significantly higher quality competitiveness, and operating profit than other companies. And low-level innovation/control HRM type companies were significantly lower quality competitiveness and operating profit than other companies.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.23-28
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• 2022

This paper analyzed the influence of employment, human resource development, and labor practices on the corporate performance. Data were collected from the Korea Labor Institute's workplace panel survey(WPS) from 2017, and the analysis used 2,868 companies. This study employed operating profit as a corporate performance. Employment included open recruitment of new employees, evaluation of NCS job competency, and implementation of core human resources acquisition program. Human resource development consisted of incumbent training, job competency improvement evaluation, management program for low performer, emoloyee's career plan, and HRD using job analysis. Labor practices included guarantees for parental leave, guarantees for maternity leave, and support for childcare facilities. The analysis method used binominal logistic regression analysis for two groups of operating profit surplus and deficit companies. As a result of the analysis, it was possible to confirm the influence of employment, human resource development, and labor practices on performance. And the implications of employment, human resource development, and labor practices to improve corporate performance were discussed.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.1
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• pp.97-114
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• 2013

The 6th Worldwide Air Transport Conference was held in Montreal in March 2013 under the auspices of ICAO. This conference, which has been held every ten years, is dealing with virtually every issue of international air transport, and aiming at updating ICAO policy in order to ensure long-term growth of international civil aviation. Last conference which took place in 2003 focused on the liberalization of air transport, and the 6th conference shifted its focus from whether to push for liberalization, to how to implement it. The main agenda items for the 6th conference was liberalization, safeguards, ownership, fair competition, airports and air navigation facilities, charges, and ICAO policy. The liberalization, and in particular progressive liberalization has been a main theme over the past decades. In the process leading to liberalization, there needs to be the expansion of market access, easing regulation on ownership and control of airlines. Furthermore, the provision of enough infrastructure such as airport and air navigation facilities may be contributing factor to remove impediments to liberalization. However, out of concern as for undermining interests of consumer and the weak, when liberalization is proceeding in a sudden and radical manner, there should be safeguards so as to ensure market participation by developing countries, consumer protection, and economical and transparent decision on taxes and charges. Fair competition which differs from promoting competition in the market, is a policy in order to protect the weak players and consumers from monopoly and oligopoly. The Korean delegation submitted 3 WPs (WP/85, 86 and 87) and 1 IP, and presented WPs, at the conference, which were a lot compared with previous occasions. A paradigm shift was emphasized to expedite the process of liberalization at the 6th conference. The reality is that with many previous recommendations to stress the importance of liberalization, and to urge States to change their attitudes, the pace of the liberalization has been very slow and staggering. The liberalization of air transport will contribute to the growth of air transport and related industry, to create new employment, promoting tourism and regional development, and further to facilitating mutual understanding and exchange, which will also lead to making a barrier-free world. In this context, it is expected that the next conference will also evaluate the on-going process of liberalization.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.979-984
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• 2006

Although iron is essential for many physiological processes, excess iron can lead to tissue damage by promoting the generation of reactive oxygen species (ROS). There is increasing evidence that ROS might play an important role in the pathogenesis of cardiovascular disease. However, the effects of iron excess on platelet function and the thrombotic response to vascular injury are not well understood. We examined the effects of iron excess-induced oxidative stress and the antioxidants on platelet aggregation. Oxidative stress was accessed by either free iron $(Fe^{+2})$ or hydrogen peroxide $(H_2O_2)$, as well as their combination on washed rabbit platelets (WPs) in vitro. When WPs were stimulated with either $Fe^{+2}$ alone or a subthreshold concentration of collagen, which gave an aggregatory curve with a little effect, and a dose dependent increase in platelet aggregation was observed by increasing concentrations of $Fe^{+2}$ with $H_2O_2$. This aggregation was associated with the iron-catalyzed formation of hydroxyl radicals from $H_2O_2$, and were inhibited by NAD/NADP (proton acceptor), catalase $(H_2O_2\;scavenger)$, tiron (iron chelator), mannitol (hydroxyl radical scavenger), and indomethacin (cyclooxygenase inhibitor), but not by NADH/NADPH (proton donor), superoxide mutase, and aspirin. However, NADH/NADPH, an essential cofactor for the antioxidant capacity by the supply of reducing potentials, showed the effect of an enhanced radical formation, suggesting a role for NADH/NADPH-dependent oxidase. These results suggest that iron $(Fe^{+2})$ can directly interact with washed rabbit platelets and this aggregation be mediated by OH formation as in the Fenton reaction, inhibited by radical scavengers.