• 한국컴퓨터정보학회논문지
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• 제13권2호
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• pp.67-78
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• 2008

본 논문에서는 대규모 국가기술자격 종합관리시스템 구축 및 운영에서 중요한 관리요소인 상설검정체계가 안정성과 시스템부하 측면에서 불안요소를 가지고 있는바, 최대 효율성과 안정성을 기반으로 WBT(Web-based test)와 CBT(Computer-based test)의 장점만을 혼용한 WCBT시스템을 설계하고 구현하였다. 제안된 시스템의 성능평가를 위하여 기본적 시뮬레이션으로 파일럿시스템에서 제안 기술을 적용하여 검증 한 후 대한상공회의소 실시간 국가기술자격 시험에 적용한 결과 안정성이 입증되어 지방상공회의소까지 지속적으로 확대할 계획이다. 제안 시스템은 해외자격시험에서 자주 발생되는 통신장애 문제를 근본적으로 해결하였으며 시스템부하 측면에서 최대 효율성을 보여주었다. 본 논문에서 설계 및 구현한 WCBT 서버 및 클라이언트시스템은 운영자 및 시험 감독자의 관리체계와 편리성에서도 좋은 평가를 도출하였다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
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• pp.591-594
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• 2007

X-Internet과 X-Forms 기반의 웹 UI 개발 툴로 개발되어 클라이언트 상에서 운영되는 소프트웨어 대한 테스트 프로세스를 제안하고 사이트를 구축한다. 이러한 소프트웨어는 개발이 완료되어 운영되는 과정에도 사용자의 요구, 성능 향상, 기능 개선, 기능 추가 등의 이유로 변경이 된다. 변경된 소프트웨어를 테스트하기 위해 V-모델을 확장, 변형한 테스트 프로세스를 제안한다. 제안한 테스트 프로세스는 테스트 목표와 그 목표를 달성하기 위한 활동을 정의하는 테스트 계획을 시작으로, 테스트 케이스와 데이터를 식별하고 환경을 구축하는 분석과 설계, 테스트 케이스를 명세화하고 테스트 방법론을 적용하는 구현과 실현, 리포팅과 산출물을 정리하는 테스트 마감 단계로 진행된다. 본 논문은 테스트 프로세스를 효율적으로 관리하고 기록하여 시간과 비용을 절감할 수 있는 사이트를 구축한다.

• 한국전문물리치료학회지
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• 제24권1호
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• pp.1-8
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• 2017

Background: The multiple hop test is an active performance test that has been commonly used to assess individuals with functional ankle instability. Previous studies have suggested that insufficiency of dynamic postural stability and passive stability during dynamic activities can have an influence on performance in the multiple hop test. However, no study has investigated the effects of dynamic postural stability training and ankle bracing on multiple hop test performance in individuals with functional ankle instability. Objects: The purpose of this study was to compare the immediate effects of dynamic postural stability training versus ankle bracing in the performance of the multiple hop test for participants with functional ankle instability. Methods: Twenty-nine participants with functional ankle instability who scored below 24 in the Cumberland Ankle Instability Tool were selected. The participants were randomly divided into two groups: a dynamic postural stability training group (n1=14) and an ankle bracing control group ($n_2=15$). The multiple hop tests were performed before and after applying each intervention. Dynamic postural stability training was performed using visual-feedback-based balance-training equipment; participants in this group were asked to perform a heel raise in a standing position while watching the centering of their forefoot pressure to prevent excessive ankle inversion. Ankle bracing was applied in the control group. Results: When comparing the pre- and post-intervention period for both groups, both methods significantly improved the results of the multiple hop test (p<.05). However, no significant differences were shown between the dynamic postural stability training and ankle bracing groups (p>.05). Conclusion: Both dynamic postural stability training and ankle bracing showed significant improvement (2.85 seconds and 2.05 seconds, respectively) in test performance. Further study is needed to determine the long-term effects of dynamic postural stability training and to determine whether insufficient dynamic postural stability is a causative factor for functional ankle instability.

• 한국산업융합학회 논문집
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• 제21권6호
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• pp.419-427
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• 2018

In case high strength steels are applied for press-formed automotive parts, it is very difficult to secure forming accuracy due to large springback compared to moderate strength steels. In this study, a repetitive step-wise forming analyses based on secant method was proposed as the die design method for mandrel(bending tool) for the 2-axis bending equipments. A bending die with circular mandrel was designed for the DP780 blow motor case of which diameter and thickness are 70.8mm and 2.0mm respectively. Forming tests were performed to verify the validity of established die design and the results were compared with that of conventional HGI(Hot galvanized iron steel) blow motor case. For additional improvement in forming accuracy, an elliptical mandrel was proposed and its validity was verified using forming analyses based on secant method.

• 한국BIM학회 논문집
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• 제8권1호
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• pp.24-32
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• 2018

A construction machine guidance system is an assistance system that helps construction equipment operators dig grounds during excavation work at a construction site. This system has long been applied in the overseas countries of the United States, Japan and Europe. However, the system has not been paid much attention in Korea. The objective of this paper is to present a business model for adopting construction machine guidance systems in Korea and evaluate the effectiveness of applying the system to excavation work. The business model in this study shows a new process of applying construction machine guidance system, business stakeholders and revenues, and suggests the benefits to the business stakeholders. A field test of the construction machine guidance system proves that the system can be applied as a tool that can improve the productivity of excavation work. This productivity improvement consequently demonstrates that the business model in this study is a prospective challenge in improving the effectiveness of excavation work at the construction site.

• 한국표면공학회지
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• 제53권6호
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• pp.271-279
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• 2020

Non-ferrous metals, widely used in the mechanical industry, are difficult to machine, particularly by drilling and tapping. Since non-ferrous metals have a strong tendency to adhere to the cutting tool, the tool life is greatly deteriorated. Diamond-like carbon (DLC) is one of the promising candidates to improve the performance and life of cutting tool due to their low frictional property. In this study, a sacrificial DLC layer is applied on the hard nitride coated drill tool to improve the durability. The DLC coatings are fabricated by controlling the acceleration voltage of the linear ion source in the range of 0.6~1.8 kV. As a result, the optimized hardness(20 GPa) and wear resistance(1.4 x 10-8 ㎣/N·m) were obtained at the 1.4 kV. Then, the optimized DLC coating is applied as an sacrificial layer on the hard nitride coating to evaluate the performance and life of cutting tool. The Vickers hardness of the composite coatings were similar to those of the nitride coatings (AlCrN, AlTiSiN), but the friction coefficients were significantly reduced to 0.13 compared to 0.63 of nitride coatings. The drilling test were performed on S55C plate using a drilling machine at rotation speed of 2,500 rpm and penetration rate of 0.25 m/rev. The result showed that the wear width of the composite coated drills were 200 % lower than those of the AlCrN, AlTiSiN coated drills. In addition, the cutting forces of the composite coated drills were 13 and 15 % lower than that of AlCrN, AlTiSiN coated drills, respectively, as it reduced the aluminum clogging. Finally, the application of the DLC sacrificial layer prevents initial chipping through its low friction property and improves drilling quality with efficient chip removal.

• 한국정보통신학회논문지
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• 제21권5호
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• pp.885-892
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• 2017

본 논문에서는 기존 전원차단회로의 공급전원 차단 복귀 시간 지연 문제를 해결하기 위하여 고속 방전 충전 스위칭 기능을 갖는 새로운 전원차단회로를 제안하였다. 제안된 전원차단회로는 공급전원 고속 차단 후 복귀(충전) 속도를 증가시키도록 설계함으로써 전자시스템의 방사선 노출 시간과 펄스 방사선이 지나간 후 정상동작하기 위한 시간을 줄였다. 하드웨어를 구현하기 전 방전 충전 시간의 시뮬레이션은 Cadence 사의 pspice tool을 이용하여 진행하였으며 소자레벨에서 DUT(Device Under Test) 보드를 제작하였다. 전원차단회로의 비교 측정은 24V용 인공위성 전자소자를 대상으로 수행되었다. 그 결과, 제안된 회로는 기존 회로에 비하여 방전속도 96.8%, 복귀속도 27.3% 향상으로 고속 기능이 구현됨을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.821-832
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• 2011

Recently, the noise of vehicle is the one of the key factors for customers to purchase a vehicle and the most important part which is related to the noise is the exhaust system. Thus, car makers have their own ways to assess this exhaust noise not only to decrease the level of noise but to enhance the feeling of it. Typically, to do these things in the early stage of development, the tuning code of the exhaust system has to be made by CAE tool, which is very reliable but expensive, and the prototype parts of this code would be made for the validation test. Then this process can be iterated to meet the target of the performance. In this study, a new algorithm which adapts the '3 dimensional convective sound wave theory 'and 'Doppler effect' has been developed. With this new algorithm, a brand new system for the calculation of tail pipe noise has been developed and validated by acoustic wind tunnel test. As a result of this study, various comparisons and have been carried out, for example, the comparison with other CAE tool has been performed for the validity and the improvement of the new calculation code could be achieved.

• 한국공작기계학회논문집
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• 제15권6호
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• pp.32-37
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• 2006

Micron size Co-alloy(T800) powder was coated on Inconel 718 by HVOF thermal spraying for the studies of the improvement of durability of high speed spindle by using Taguchi program for the parameters of spray distance, flow rates of hydrogen and oxygen and powder feed rate. The optimal coating process was determined by the studies of coating properties such as micro-structure, porosity, surface roughness and micro hardness. Friction and wear behaviors of coatings were investigated by sliding wear test at room temperature and $1000^{\circ}F(538^{\circ}C)$. At both room temperature and $538^{\circ}C$ the sliding wear debris and friction coefficients of the coating were drastically reduced compared with the surface of non-coated parent material. This shows that Co-alloy powder coating is highly recommendable for the durability improvement surface coating of high speed air-bearing spindle. At high temperature wear traces and friction coefficients of both coating and non-coating were drastically reduced compared with those of room temperature since the brittle oxides were formed easily on the surface, and the brittle oxide phases were attrited by the reciprocating sliding wear according to the complicated mixed wear mechanisms These oxide particles, partially melts and the melts play role as lubricant and reduce the wear and friction coefficient. This also shows that Co-alloy powder coating is highly recommendable far the durability improvement surface coating on the surface vulnerable to frictional heat such as high speed spindles.

• 인간식물환경학회지
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• 제24권6호
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• pp.707-718
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• 2021

Background and objective: Due to the recent crisis of extinction in local areas, the mountain village promotion policy is recognized as an important task. This study examined the priorities of major policy projects in the forest sector that affect mountain village promotion. Methods: For research methods, literature search, expert advisory meetings, and a survey were conducted. The survey was conducted on 42 policy stakeholders from June 1 to August 13, 2021. The literature search was based on policy projects in the forest sector by 8 upper-level local governments including mountain villages. For questionnaire items, 173 forest policy projects were classified into 27 types through expert review, and the importance and performance of each type were rated on a 5-point Likert scale. Paired t-test, IPA, Locus for Focus model, and Borich needs assessment were used as the analysis methods, and the statistical program SPSS 21.0 was used as the analytical tool. Results: The results showed that 'creating forest-related jobs' and 'supporting cultivation of professional forestry workers' both showed high importance and performance, implying that they would show an effect in mountain village promotion. 'Creating forests for environmental improvement', 'discovering forest cultural assets' 'establishing and boosting forest tourism', 'providing forest therapy services', 'creating forest-related jobs', 'supporting community revitalization', and 'urban-rural exchanges' were found to be the types that needed improvement and concentration for mountain village promotion. In particular, 'creating forests for environmental improvement' and 'discovering forest cultural assets' were derived as priority considerations for mountain village promotion policies. Conclusion: In summary, it was found that in order to promote mountain villages, various content projects must be improved and carried out to enhance the physical environment and revitalize mountain villages.