• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.542-547
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• 2015

Since the oil price has been significantly jumped for several years, a heavy oil of low quality has been mainly used in the diesel engine of the merchant ship. Thus, a combustion chamber of the engine has been often exposed to severely corrosive environment more and more because temperature of the exhaust gas of the combustion chamber has been getting higher and higher with increasing of using the heavy oil of low quality. As a result, wear and corrosion of the engine parts such as exhaust valve, piston crown and cylinder head surrounded with combustion chamber are more serious compared to the other parts of the engine. Therefore, an optimum repair welding for these engine parts is very important to prolong their lifetime in a economical point of view. In this study, Inconel 625 filler metal were welded with GTAW method in the cast steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected and base metal zones were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% $H_2SO_4$ solution. The weld metal and base metal zones exhibited the highest and lowest values of hardness respectively. Furthermore, the corrosion current density of the weld metal zone revealed the lowest value, having the highest value of hardness. The corrosive products with red color and local corrosion like as a pitting corrosion were considerably observed at the base metal zone, while these morphologies were not wholly observed in the weld metal zone. In particular, the polarization characteristics such as impedance, polarization curve and cyclic voltammogran associated with corrosion resistance property were well in good agreement with each other. Consequently, it is suggested that the mechanical and corrosion characteristics of the piston crown can be predominantly improved by repair welding method using the Inconel 625 electrode.

• 전자공학회논문지
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• 제53권9호
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• pp.26-37
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• 2016

현재 전달망의 핵심기술은 링크 또는 노드 장애가 발생했을 경우에 경로 이중화를 통해 50ms이내에 망을 복구하는 OAM 및 보호절체 기술이다. 개별 통신사업자, 지방/중앙 정부, 중요 기업의 전달 망은 장애에 대한 실시간 망 복구를 위해 보호 서브네트워크를 개별적으로 설정, 관리되고 있다. 그래서 개별 보호 서브네트워크의 종단 노드에 대해 노드 이중화를 적용하여 종단 노드 장애에 대해 대비하는 것이 중요하다. 하지만 MPLS-TP, 캐리어 이더넷과 같은 패킷 전달망에서 선형 보호절체가 적용되는 보호 서브네트워크는 이중 노드 상호 연결 방안이 존재하지 않는다. 비록 이더넷 링 보호절체는 이중 노드 상호 연결방안을 포함하고 있지만 이더넷 링 보호절체의 기술적 특성상 연결 노드에서 장애가 발생하면 전이 트래픽이 급격하게 증가될 수 있다. 본 논문에서는 보호 서브네트워크에서 연결 노드 이중화를 위한 선형 보호절체 적용 방안을 제시한다. 그리고 링크와 상호 연결 노드의 장애에 대한 여러 실험을 통해 제안된 선형 보호와 링 보호 프로세스의 다양한 조합이 어떻게 다중 보호 서브네트워크에서 서비스 트래픽의 복구 탄력성에 영향을 미치는 지를 분석한다.

• 한국ITS학회 논문지
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• 제9권6호
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• pp.13-21
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• 2010

도로교통공단과 경찰청은 2005년부터 전국 주요도시에 교통정보센터, 도로교통정보시스템(UTIS), CCTV, VMS 통신망 등 교통정보 기반시설을 설치하는 "도시지역 광역교통정보 기반확충사업"을 추진 중에 있다. 중앙교통정보센터는 국내 교통정보 허브(Hub) 기능을 담당하는 동시에 표준화된 광역교통정보관리체계의 구축 및 지역간 구분없는 UTIS 교통정보를 제공하는 역할을 수행하고 있다. 본 연구에서는 중앙교통정보센터를 통해 통합 제공되는 UTIS 교통정보 서비스의 효율적 추진과 품질향상을 도모하기 위한 방안을 모색하기 위해 수행되었다. 최종수요자(End-User) 요구분석, 기존사례검토 및 계층적 분석기법(AHP) 등을 활용하여 UTIS 교통정보 제공서비스의 성과평가지표를 개발하였으며, 평가시행방안을 수립 제시하였다. 개발된 성과평가지표는 총 5개 부문 20개 지표로 구성되어 있으며, UTIS 교통정보 제공에 따른 직접적/간접적 평가가 가능토록 하였다. 본 연구에서 제시된 평가지표 및 평가방법을 활용함으로써 중앙교통정보센터 UTIS 교통정보 제공서비스의 품질 개선을 도모할 수 있을 것으로 기대되며, 타 교통정보시스템의 운영성과 평가 시에도 확장 적용이 가능할 것으로 판단된다.

• Smart Structures and Systems
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• 제21권5호
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• pp.687-694
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• 2018

The problem of wheel tread defects has become a major challenge for the health management of high-speed rail as a wheel defect with small radius deviation may suffice to give rise to severe damage on both the train bogie components and the track structure when a train runs at high speeds. It is thus highly desirable to detect the defects soon after their occurrences and then conduct wheel turning for the defective wheelsets. Online wheel condition monitoring using wheel impact load detector (WILD) can be an effective solution, since it can assess the wheel condition and detect potential defects during train passage. This study aims to develop an FBG-based track-side wheel condition monitoring method for the detection of wheel tread defects. The track-side sensing system uses two FBG strain gauge arrays mounted on the rail foot, measuring the dynamic strains of the paired rails excited by passing wheelsets. Each FBG array has a length of about 3 m, slightly longer than the wheel circumference to ensure a full coverage for the detection of any potential defect on the tread. A defect detection algorithm is developed for using the online-monitored rail responses to identify the potential wheel tread defects. This algorithm consists of three steps: 1) strain data pre-processing by using a data smoothing technique to remove the trends; 2) diagnosis of novel responses by outlier analysis for the normalized data; and 3) local defect identification by a refined analysis on the novel responses extracted in Step 2. To verify the proposed method, a field test was conducted using a test train incorporating defective wheels. The train ran at different speeds on an instrumented track with the purpose of wheel condition monitoring. By using the proposed method to process the monitoring data, all the defects were identified and the results agreed well with those from the static inspection of the wheelsets in the depot. A comparison is also drawn for the detection accuracy under different running speeds of the test train, and the results show that the proposed method can achieve a satisfactory accuracy in wheel defect detection when the train runs at a speed higher than 30 kph. Some minor defects with a depth of 0.05 mm~0.06 mm are also successfully detected.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.612-616
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• 2004

This study was carried out to compare the semen characteristics, frozen-thawed sperm viability and testosterone concentration and in vitro fertilization (IVF) and development of in vitro matured pig oocytes between two Yorkshire boars. Semen and blood samples were collected once per week from October to November 2002 from two adult Yorkshire boars at 18 months of age with 170 kg body weight. Sperm were deep frozen in 5 ml maxi-straws with lactose-egg yolk and N-acetyl-D-glucosamine (LEN) diluent and stored in liquid nitrogen. Blood samples were obtained at 10 a.m. by inserting a 21 gauge, hypodermic needle attached to 10 ml syringe into surface veins in the ear. The concentration of testosterone was determined by Competitive Enzyme Immunoassay. Ovaries were collected from prepubertal gilts at a local slaughter house. Cumulus oocyte complexes were aspirated from antral follicles (3 to 6 mm in diameter). The medium used for oocyte maturation was modified TCM 199. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at $38.5^{\circ}C$, 5% $CO_2$ in air. For IVF, one frozen 5 ml straw was thawed at $52^{\circ}C$in 40 sec and was diluted with 20 ml Beltsville thawing solution at room temperature. Sperm were washed 2 times in mTLP-PVA and inseminated without preincubation after thawing. Oocytes were inseminated with $2{\times}10^7$/ml sperm concentration. Oocytes were coincubated for 6 h in 500 ${\mu}$l mTBM fertilization medium. At 6 h after IVF, oocytes were transferred into 500 ${\mu}$l NCSU-23 culture medium for further culture of 48 and 144 h. There were no significant differences in the semen volume, motility, normal acrosome morphology and sperm concentration of raw semen between A and B of Yorkshire boar. However, motility and normal acrosome of boar A were higher than those of boar B at 0.5, 2, 3, 4, 5 and 6 h incubations of frozen-thawed sperm. Testosterone concentration (3.75 ng/ml) of boar A was higher than that (2.34 ng/ml) of boar B. The rate of blastocyst formation (15.1%) of boar A was higher than that (10.4%) of boar B. In conclusion, serum testosterone concentration of boar showed very important role for the frozen-thawed sperm viability and the blastocyst formation of pig oocytes matured in vitro.

• Journal of East Asia Management
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• 제1권1호
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• pp.29-49
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• 2020

In an intensively competitive global market, small-and medium-sized firms are puzzled about how to develop sustainable competitive advantages against global rivalries, thus leading satisfactory economic performance. However, despite the roles and contributions of such small-and medium-sized firms in the local community and national economies in Japan, little guidance has been offered to the practical issues related to their strategic behaviors toward global management. To fill this notable knowledge gap, this study aims to investigate the conditions in which how Japanese small-and medium-sized could dominates global market, which is one of key challenges in the literature of small business and entrepreneurship. To obtain better insights to this research area, this study undertakes an in-depth interview survey with I.S.T (Industrial Summit Technology) Corporation that shows off the highest global market share (40 per cent) with seamless polyimide tube product widely used in office automation equipment (e.g., copiers and printers). This method of survey is designed to deeply understand historical considerations about how I.S.T Corporation could dominate in the global market of such seamless polyimide tube product. Based on findings drawn from an interview, this study identifies five major factors enabling I.S.T Corporation to be a competitive global hidden company: vision sharing through founder's entrepreneurship, core competence, strategic network, risk management, and employee engagement. Specifically, to become a global hidden champion, sharing the vision motivating employees to partake in shaping company's future will be the first step on the road to global success through founder's entrepreneurship. However, in order to achieve such a vision, the importance of company's core competence cannot be overemphasized, which differentiates your customer solution with those of competitors. As such, a group of experts will be naturally formed and demonstrates your expertise in the global market, thereby building sustainable competitiveness. On the other hand, to maintain sustainable competitiveness, it is necessary to make up for the weaknesses small-and medium-sized firms suffer from competitive resources while strengthening their own strengths through strategic networks with external organizations. Here, every company has to understand the critical role of risk management, which is essential in this process of being global company so as not to lose your own strengths. Last but not least, do not forget the significant effects of employee engagement in firm performance. To enhance employees' engagement, a company has to create an ideal organization culture which fits into company's history and personality. In doing so, such organization culture can allow the vision and strategy to be implemented into detailed business tactics while facilitating employees to challenge the status quo by experimenting with creative ideas.

• 한국산학기술학회논문지
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• 제18권12호
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• pp.140-149
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• 2017

최근 기후변화에 따른 다목적 하천기능관리가 요구되고 있지만, 국내 하천분야는 국가하천과 지방하천의 관리주체가 분리되어 하천정보를 통합적으로 운영하지 못하고 있다. 특히 설계 및 건설 준공도서를 재활용한 하천정보의 작성과 갱신이 미흡하다. 또한 하천기본정보는 GIS기반의 RIMGIS 시스템의 의존도가 큰 반면, 하천기본계획 성과물에 의한 공간정보 구축으로 하천정보의 신뢰성이 저하되고 있는 현실이다. 본 연구에서는 하천분야에서 다루는 정보의 활용범위가 다양하나 하천시설물의 유지와 운영을 위한 정보체계를 대상으로 하며 현행 하천시설물 유지운영 관련 정보체계의 현황을 조사 및 분석하여 현안 문제점을 도출하고, 시범적용 사례 검증을 통해 실무정보적인 관점에서 최적의 해결방안을 제시하였다. 그 결과로 상시적으로 신뢰할 수 있는 하천 시설물 유지관리 정보체계를 구축하고 정보통합운영 방안을 검토하였다. 본 연구는 앞으로 하천시설 통합 유지운영을 위한 정보 현행화와 기술적, 제도적인 절차를 개선하는데 활용될 수 있다. 또한 하천분야의 정보구축 개선을 위한 정보프레임워크 구축 방향제시를 통하여 앞으로 타 분야와 정보격차를 해소 할 뿐만 아니라 BIM정보체계를 도입하는데 도움이 될 것이다.

• 한국표면공학회지
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• 제41권6호
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• pp.292-300
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• 2008

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in prosthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were characterized, using field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The stability of TiN and WC coated abutment screw was evaluated by potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screws was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased as following order; TiN coating, WC coating and non-coated screw. The pitting potentials of TiN and WC coated specimens were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen was lower than those of TiN coated and non-coated abutment screws due to breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screws.

• The Korean Journal of Pain
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• 제19권2호
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• pp.187-191
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• 2006

Background: Patient-controlled epidural analgesia (PCEA), using a local anesthetic-opioid mixture, has been effectively applied after total knee replacement (TKR) surgery, which is associated with intense postoperative pain that requires postoperative analgesia for both rehabilitation and the pain itself. However, adverse opioid-related effects, such as nausea, vomiting and pruritus, are commonly encountered. It was our hypothesis that the adverse opioid-related effects could be reduced by the addition of naloxone, an opioid antagonist, to a mixture of fentanyl-ropivacaine PCEA. Methods: In 120 patients undergoing elective TKR surgery, epidural or combined spinal-epidural (CSE) anesthesia was performed and PCEA applied. In the control group (n = 65), 0.16% ropivacaine and $3{\mu}g/ml$ fentanyl ($2.4{\mu}g/ml$ for those older than 65 yrs) were administered. In the naloxone group (n = 55), naloxone ($2{\mu}g/ml$) was coadministered with the above regimen. The incidence and severity of postoperative nausea and vomiting, and the frequency of pruritus, the visual analog score (VAS) and the PCEA volume used were assessed 6 and 24 hrs after surgery. Results: The incidence of nausea and vomiting during the early postoperative period, and those of pruritus during the late postoperative period were significantly lower in the naloxone group. The VAS pain scores, the PCEA volume used and amount of rescue IV meperidine were similar in the two groups. Conclusions: A small dose of naloxone mixed with an opioid significantly reduces the incidence and severity of adverse opioid-related effects in PCEA, without reducing the analgesic effect.

• 산경연구논집
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• 제9권8호
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• pp.51-60
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• 2018

Purpose - Civil affairs are increasing in various forms, but civil servants who are able to handle them want to reduce the complaints and provide keywords that will help in the future due to their lack of time. While various ideas are presented and implemented as policies in solving civil affairs, there are many cases that are not policies that people can sympathize with. Therefore, it is necessary to analyze the complaints accurately and to present correct solutions to the analyzed civil complaint data. Research design, data, and methodology - We analyzed the complaints data for the last three years and found out how to solve the problems of Yongin City and alleviate the burdens of civil servants. To do this, the Hadoop platform and Design Thinking process were reviewed, and proposed a new process to fuse it. The big data analysis stage focuses on civil complaints - Civil data extraction - Civil data analysis - Categorization of the year by keywords analyzing them and the needs of citizens were identified. In the forecast analysis for deriving insights, - The case of innovation case study - Idea derivation - Idea evaluation - Prototyping - Case analysis stage used. Results - Through this, a creative idea of providing free transportation cards to solve the major issues of construction, apartment, installation, and vehicle problems was discovered. There is a specific problem of how to provide these services to certain areas, but there is a pressing need for a policy that can contribute as much as it can to the citizens who are suffering from various problems at this moment. Conclusions - In the past, there were many cases in which free traffic cards were issued mainly to the elderly or disabled. In other countries, foreign residents of other area visit the areas for accommodation, and may give out free transportation cards as well. In this case, the local government will be able to set up a framework to present with a win-win scenario in various ways. It is necessary to reorganize the process in future studies so that the actual solution will be adopted, reduce civil complaints, help establish policies in the future, and be applied in other cities as well.