• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.680-690
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• 2022

Vibrations in the pipe system trigger fatigue-related issues and lead to fatal other problems caused by pipe damage. There are numerous studies to analyze and reduce the cause of pipe vibration, among which a small number of studies are being conducted on pipe vibration reduction using friction supports. The study of friction supports, however, focused only on predicting and evaluating the performance of the friction supports and seldomly considered the design perspective of the install location of the supports. Therefore, this study intends to suggest the optimization process for finding the best installation region of friction support to attenuate the vibration of entire piping system. The optimal position of the friction support is predicted only by linear analysis to guarantee optimization efficiency in the design process. The designed friction support location is verified by time domain analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.151-162
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• 2022

Prefab members have attracted attention because they can be mass-produced in factories through smart construction technology. For prefab prestressed concrete girders, it is important to manage the shapes of the girders properly from production to the pre-installation stage for consistency with the prefab floor plate during the erection process. This paper presents a camber reconstruction method using collocated strain measurements from the top and bottom of the prefab girder. In particular, the camber reconstruction method is applied to measured strain data in which the time-dependent behavior of concrete is considered after the introduction of prestress. Through Monte Carlo numerical simulations, the statistical accuracy of the reconstructed camber for a limited number of sensors, measurement errors, and nonlinear time-dependent behaviors are analyzed and validated.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.53-64
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• 2024

The Yeongnam southeastern region, with Ulsan as its focal point, is planning large-scale floating offshore wind power projects. Additionally, due to the establishment of new nuclear power plants and the extension of existing ones, there is a demand for the expansion of the power grid. The government has announced plans to establish a new power grid for this region as part of the 10th power supply plan. However, there are anticipated challenges in the actual construction phase, primarily because of the presence of national parks and cultural heritage protection zones near Gyeongju. As a result, this study presents an alternative approach that minimizes the creation of new power lines by utilizing existing ones. Using the Power System Simulator for Engineers (PSS/E), an analysis of transient stability was conducted and demonstrated its feasibility.

• Journal of The Korean Association For Science Education
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• v.34 no.8
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• pp.703-718
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• 2014

This study sought to investigate learning progressions for astronomical systems which synthesized the motion and structure of Earth, Earth-Moon system, solar system, and the universe. For this purpose we developed ordered multiple-choice items, applied them to elementary and middle school students, and provided validity evidence based on the consequence of assessment for interpretation of learning progressions. The study was conducted according to construct modeling approach. The results showed that the OMCs were appropriate for investigating learning progressions on astronomical systems, i.e., based on item fit analysis, students' responses to items were consistent with the measurement of Rasch model. Wright map analysis also represented that the assessment items were very effective in examining students' hypothetical pathways of development of understanding astronomical systems. At the lower anchor of the learning progression, while students perceived the change of location and direction of celestial bodies with only two-dimensional earth-based view, they failed to connect the locations of celestial bodies with Earth-Moon system model, and they could recognized simple patterns of planets in the solar system and milky way. At the intermediate levels, students interpreted celestial motion using the model of Earth rotation and revolution, Earth-Moon system, and solar system with space-based view, and they could also relate the elements of astronomical structures with the models. At the upper anchor, students showed the perspective change between space-based view and earth-based view, and applied it to celestial motion of astronomical systems, and they understood the correlation among sub-elements of astronomical systems and applied it to the system model.

• Korean Journal of Construction Engineering and Management
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• v.17 no.6
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• pp.31-39
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• 2016

This study aims to give suggestions based on survey to improve the quality of Global Construction Engineer Training Program in line with the government goals. The domestic construction industry in Korea has kept shrinking, whereas the global construction market is forecasted to keep expanding in the future. It has become an urgent task to be taken up for construction contractors and engineering firms so as to improve their capacity, in particular, in the fields of planning, management, finance as well as engineering. To deal with the lack of capacity of the domestic engineers and to help them emerge as global players in the competitive overseas construction market, the Ministry of Land, Infrastructure and Transport of the Korean government has designed a program called 'Global Construction Engineer Training Program.' The eligible target of the training program is mid-career professionals who are working for the construction contractors or engineering firms. To draw suggestions for this program, an importance-satisfaction analysis is conducted to evaluate the effectiveness of the training program implemented by the S University. The S University, along with C University, was selected as an implementation organization of the program in 2014 by the government. Through an email survey, the participating students in the program were asked questions on the importance and satisfaction against 17 indicators classified into 5 categories: instruction method, professional knowledge of instructors, contents of program, curriculum, and facility and environment. The survey results show that students are satisfied with the overall quality of the program, but it was also found that they want the program opens more coursework on practical application of knowledge, case studies, and global networking.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.181-194
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• 2017

This study aims to develop a regression model for forest volume estimation using field-collected forest inventory information and airborne LiDAR data. The response variable of the model is forest stem volume, was measured by random sampling from each individual plot of the 30 circular sample plots collected in Bonghwa-gun, Gyeong sangbuk-do, while the predictor variables for the model are Height Percentiles(HP) and Height Bin(HB), which are metrics extracted from raw LiDAR data. In order to find the most appropriate model, the candidate models are constructed from simple linear regression, quadratic polynomial regression and multiple regression analysis and the cross-validation tests were conducted for verification purposes. As a result, $R^2$ of the multiple regression models of $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}$ among the estimated models was the highest at 0.509, and the PRESS statistic of the simple linear regression model of $HP_{25}$ was the lowest at 122.352. $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}-based$ models, thus, are comparatively considered more appropriate for Korean forests with complicated vertical structures.

• International Commerce and Information Review
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• v.16 no.1
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• pp.145-161
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• 2014

The study has try to find out the relationship between airfreight service quality and satisfaction in international forwarding practice which has focused to figure out the mediating role of performance that measured as subjective evaluation on profit. For the purpose of this paper, questionnaire survey has been performed on the relationship among the procedure of the air freight service quality was found to have not only direct influence but also indirect impact through performance on satisfaction. This research made some contribution both academicals and logistic practices. Academically, it is the first research to address the relationship between air freight service quality and profit performance in Korean academic field. Practically, this study provides justification for the investment to improve forwarding service quality. The results of this study bear some implications on international shipping and practice. The quality of the air cargo transportation management system for customer satisfaction and its impact on business performance in the process to make an empirical identifies. The role and influence of the working-level analysis to derive the performance as transportation management, as well as the effectiveness of customer satisfaction for quality and promote a point. Arrange this point take advantage of air cargo companies are composed of service quality management system for the dimension of course aims to foster a competitive advantage in terms of performance. This paper suggest that real-time movement of the consignment route provides information such as verification and business cooperation for the purpose of proper features a reflecting on the stability of cargo air freight management system, that improve the quality of services on this performance to increase the customer satisfaction strategy in connected getting and so on, is in the process of the formation of customer satisfaction.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.450-453
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• 2003

본 논문에서는 그룹별 가변 길이 직교코드 다중화를 이용한 OFDM (orthogonal frequency division multiplexing) 전송방식의 제안하고, 그룹별로 동일한 부반송파 개수를 가정하여 코드 길이에 따른 시스템 성능과 복잡도를 분석함으로써 최적의 시스템 파라미터들을 결정한다. 제안된 방식에서는 상호 상관성이 낮은 부반송파들로 동일 반송파 그룹으로 구분함으로써 부반송파 전체를 다수의 부반송파 그룹으로 나누고, 그룹마다 부반송파 개수와 동일한 길이의 직교코드들을 사용하여 다중화하여 전송한다. 따라서, 제안된 시스템을 사용하면 적절한 시스템 파라미터의 선정을 통하여 부반송파 전체를 하나의 그룹으로 하는 기존의 직교코드 다중화 방식에[2] 비하여 다이버시티 이득은 유지하면서 시스템 복잡도를 크게 줄일 수 있다. 또한, 제안된 직교코드 다중화 전송방식에서는 수신기에서 직교코드들간의 직교성 복원이 필수적이며, 수신기에서 불완전한 채널등화는 인접한 직교코드들 간에 상호 간섭을 유발하는 요인이 된다. 따라서, 채널추정 오류의 정도가 증가함에 따라 직교코드들 간의 상호 간섭으로 인하여 증가하는 비트오류를 줄이기 위하여 채널추정 오류의 정도에 따라 블록길이와 블록 인터리버 구조를 조절하여 시스템을 최적화 한다. 가변 길이 직교코드로는 길이에 상관 없이 직교성을 유지하며 에너지의 균등 분배가 가능한 DFT (discrete Fourier transform) 코드를 사용한다. 최적 시스템 파라미터를 결정하기 위하여 모의실험을 통하여 코드 길이에 따른 시스템 성능을 분석한다. 또한, 채널추정 오류가 존재하는 경우에 시스템 성능을 분석한다. 마지막으로, 채널 부호화를 적용하는 경우에 시스템 파라미터들을 최적화함으로써 부호화 이득이 시스템 성능과 시스템 복잡도 감소, 채널추정 오류의 극복에 미치는 영향을 분석한다. nature, in contrast to physical theories that are of a geometrical nature. An application to the interpretation of intelligence is proposed, based on the "intelligence"of movement. Co layer from 1.4 to 1.6 nm was measured to be ranged from 0.004 to 0.021 ${\AA}$$\^$-1/.문에 기업간 관계를 연구하는 측면에서는 탐험적 연구성격이 강하다. 더 나아가 본 산업의 주된 연구가 질적이고 기업내부만을 연구했던 것에 비교하면 시초적이라고 할 수 있다. 또한 관계마케팅, CRM 등의 이론적 배경이 되고 있는 신뢰와 결속의 중요성이 재확인하는 결과도 의의라고 할 수 있다. 그리고 신뢰는 양사 간의 상호관계에서 조성될 수 있는 특성을 가진 반면, 결속은 계약관계 초기단계에서 성문화하고 규정화 할 수 있는 변수의 성격이 강하다고 할 수가 있다. 본 연구는 복잡한 기업간 관계를 지나치게 협력적 측면에서만 규명했기 때문에 많은 측면을 간과할 가능성이 있다. 또한 방법론적으로 일방향의 시각만을 고려했고, 횡단적 조사를 통하고 국내의 한 서비스제공업체와 관련이 있는 컨텐츠 공급파트너만의 시각을 검증했기 때문에 해석에서 유의할 필요가 있다. 또한 타당성확보 노력을 기하였지만 측정도구 면에서 엄격한 개발과정을 준수하지는 못했다. 향후에는 모바일 컨텐츠 파트너의 기업의 특성을 조사하여 관계성 변수와의 상호관련연구를 진행할 필요가 있다. 관계기간, 의존성, 거래처의 단/복수여부, 서비스 범주 등의 제반 변수를 고려하여 이러한 변수가 양사와의 관계성 변수에 어떤 영향이 있는가를 검증할 필요가 있다. 또한 신뢰,

• Journal of Environmental Policy
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• v.8 no.4
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• pp.25-36
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• 2009

The Total Pollutant Load Management System(TPLMS) in the Han River basin is being changed from a voluntary to a mandatory system. Accordingly, this study suggests directions and priorities for research that can support implementation of TPLMS through an objective approach that deploys gap analysis and analytic hierarchy processes (AHP). Gap analysis indicated that TPLMS in Korea is still focused on compliance with regulations, and that implementation of TPLMS is still in its early stage. Improvements are thus needed in flexibility and effectiveness, including introduction of emissions rights trading, and upgrading to a renewable emissions permit system. The AHP study indicated that R&D will need to proceed in parallel in multiple areas to improve systems and resolve scientific uncertainties. Balanced R&D will be needed in both the institutional and technical groups. Subgroup analysis indicated that developing a reasonable process to establish water quality management targets is of the highest priority in the institutional group. In the technical group, higher priority will need to be given to improving model reliability and developing innovative pollution load reduction technologies.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.577-588
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• 2003

정보기술의 급진적인 발달로 경쟁이 점점 심화되어져 가고 있는 환경 속에서 경쟁적 우위를 갖기 위한 기업들의 끊임없는 노력은 계속 되고 있다 이러한 시점에 ERP(Enterprise Resource Planning: 전사적 자원관리) 시스템은 기업의 경쟁력을 재고하고 변화하는 비즈니스 환경을 예측하여 신속하고 현명하게 대처하기 위한 수단으로서의 역할을 수행하고 있으며 최근 기업뿐만 아니라 대학에서도 이에 대한 관심이 확산되고 있다. 이미 국외의 많은 대학들이 ERP 시스템을 도입한 실정이고, 국내에서는 정보화 사업의 일환으로 연세대학교가 일반 행정 업무의 효율화를 위해 SAP R/3를 도입했고 향후 학사 행정 시스템과의 통합을 모색 중이다. 정부에서도 국·공립 대학들의 행정업무효율성 제고를 위해 차세대 행정업무시스템으로 ERP 시스템 도입을 본격화하고 있다. 따라서 본 논문에서는 정보화를 추진하고자 하는 국내 대학에 ERP 시스템의 도입을 제안하였고, 기존에 선행 연구된 연구자료를 비교·분석하여 기업의 ERP 시스템 구축 성공요인을 정리하였다. 국내 대학은 ERP 시스템 도입 시 제시된 주요성공요인 등을 고려하고 지속적인 관심으로 프로젝트를 수행함으로써 보다 효과적으로 구축을 완료해야 할 것이며, 아직 국내의 사례가 충분하지 않기 때문에 본 논문에서 제시한 국내외의 사례를 살펴봄으로써 대학의 ERP 시스템 도입에 관해 빠른 이해를 할 수 있을 것이다. 끝으로 본 논문은 초기단계에 있는 국내 대학의 ERP 시스템 도입에 대학이 나가야 할 방향을 제시하였고, 앞으로 국내 대학의 ERP 시스템 도입이 증가할수록 이에 대한 연구도 계속 되어야 할 것이다.보다 더 높게 나타난 반면에, 실무계 전문가 집단은 비용이 정보시스템 보다 더 높게 나타났다는 것이다.리적 특성이론과 사용자 수용이론으로 구분하여 이 특성에 따라서 향후 개발될 3D 핸드폰 아바타의 수용도의 관계를 파악하고자 한다. 본 연구에 대한 자료 수집방법은 D대학교의 교양과목인 “사이버문화의 이해와 활용”을 수강하는 학생들을 대상으로 총 170부를 설문 조사하였으며, 수집된 설문지 중에서 불성실하게 응답한 설문지 6부를 제외한 총 164부를 유효한 설문으로 확보하였다. SPSSWIN 10.0 패키지를 이용하였으며, Cronbach's Alpha값을 통한 신뢰도 분석과 요인분석을 통한 타당성 분석을 하고, 연구변수로 선정한 각 요소들의 아바타 수용도에 미치는 영향력 정도를 파악하기 위해 회귀분석을 실시하였다. 그 결과 심리적 특성과 사용자 수용 특성은 아바타 수용도에 부분적으로 영향을 미친다는 것 결과가 나타났다.웨어 프로세스 평가와 개선 모델의 개발을 위한 기초적인 자료를 제공할 것으로 예상된다 또한, 본 연구 결과는, 우리나라 소프트웨어 조직들이 실제로 무엇을 필요로 하는지를 밝힘으로써, 우리나라의 소프트웨어 산업을 육성하기 위한 실효성 있는 정책 입안을 위한 기초 자료를 제공할 것으로 예상된다.다.를 검증하려고 한다. 협력체계 확립, ${\circled}3$ 전문인력 확보 및 인력구성 조정, 그리고 ${\circled}4$ 방문보건사업의 강화 등이다., 대사(代謝)와 관계(關係)있음을 시사(示唆)해 주고 있다.ble nutrient (TDN) was highest in booting stage (59.7%);