• 한국기계가공학회지
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• 제12권5호
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• pp.9-15
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• 2013

Roll-to-roll printing technology has lately become a subject of special interests in the field of printed electronics. Since this technology has the advantage that continuous and mass production is possible. And for high precision register control is required in multi-layer printing to produce the electronic devices, this is one of the most important technologies in roll-to-roll printing technology. Register error could be generated by various reasons like eccentricity of roll and thermal deformation due to temperature variation in drying section. In this study, the effect of tension variation on the register was analyzed. The results of these analyses show that it is essential to consider the tension disturbance which is generated by the change of temperature in drying section, and conventional register model has limitation to estimate the register error. In order to overcome the limitation of the register model, advanced register model based on the SI process was developed. Also, the performance of the developed model was verified experimentally.

• 한국항공우주학회지
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• 제48권10호
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• pp.765-772
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• 2020

항공기의 임무수행 시간을 연장하기 위해 도입된 공중급유를 수행하기 위해서는 두 항공기간의 랑데부 기동이 필수적으로 요구된다. 본 논문에서는 공중급유를 위해 가변 추적유도법칙을 이용한 랑데부 유도기법을 다룬다. 르야프노프 안정성 이론을 이용하여 가변 추적유도법칙 기반 랑데부 유도기법을 설계하였다. 제안한 유도기법은 두 항공기가 일정한 속력으로 비행하고 있을 때, 두 항공기 간의 헤딩각이 일치하도록 작동하여 랑데부 기동을 수행하도록 한다. 수치 시뮬레이션을 통해 제안한 랑데부 유도기법의 성능을 검증하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.795-800
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• 2007

In the previous study, a simple but effective analysis procedure, named as an Improved Modal Pushover Analysis (IMPA) was proposed to estimates the seismic capacities of multi-span continuous bridge structures, on the basis of the modal pushover analysis which considers all the dynamic modes of a structure. Differently from other previous studies, IMPA maintains the simplicity of the capacity-demand curve method and also gives a better estimation of the maximum dynamic response of a structure. Nevertheless, its applicability has never been approved for multi-span continuous bridges with large differences in the length of their adjacent piers. This paper, accordingly, concentrates on a parametric study to verify the efficiency and limitation in application of IMPA through a correlation study between various analytical models including the Equivalent Single Degree Of Freedom (ESDOF) and Modal Pushover Analysis (MPA) usually used in the seismic design of structures. Based on the obtained numerical results, this paper introduces a practical guidance and/or limitation for using IMPA to predict the seismic response of a bridge effectively.

• 전자통신동향분석
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• 제32권6호
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• pp.8-16
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• 2017

In this paper, we review studies attempting to triumph over the limitation of Si-based semiconductor technologies through a heterogeneous integration of high mobility compound semiconductors on a Si substrate, and the co-integration of electronic and/or optical devices. Many studies have been conducted on the heterogeneous integration of various materials to overcome the Si semiconductor performance and obtain multi-purpose functional devices. On the other hand, many research groups have invented device fusion technologies of electrical and optical devices on a Si substrate. They have co-integrated Si-based CMOS and InGaAs-based optical devices, and Ge-based electrical and optical devices. In addition, chip and wafer bonding techniques through TSV and TOV have been introduced for the co-integration of electrical and optical devices. Such intensive studies will continue to overcome the device-scaling limitation and short-channel effects of a MOS transistor that Si devices have faced using a heterogeneous integration of Si and a high mobility compound semiconductor on the same chip and/or wafer.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.29-30
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• 2012

In this paper, a performance of bi-directional DC/DC converter using PFM control at whole load range is analyzed. A bi-directional DC/DC converter using PFM control in this paper can be soft switching operation with LC series resonant circuit. It's difficult to expect a high efficiency at whole load range in general resonant converter because of limitation of soft switching area. Therefore converter used in this paper has a variable frequency PFM control to overcome a limitation of soft switching area and it makes a high efficiency at whole load range by implementing a soft switching at light load area of restricted soft switching. The high efficiency at whole load range is verified by simulation and experimental result.

• 한국IT서비스학회지
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• 제22권1호
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• pp.43-56
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• 2023

With the development of the e-commerce market, various types of products continue to be released. However, customers face an information overload problem in purchasing decision-making. Therefore, personalized recommendations have become an essential service in providing personalized products to customers. Recently, many studies on GCN-based recommender systems have been actively conducted. Such a methodology can address the limitation in disabling to effectively reflect the interaction between customer and product in the embedding process. However, previous studies mainly use implicit feedback data to conduct experiments. Although implicit feedback data improves the data scarcity problem, it cannot represent customers' preferences for specific products. Therefore, this study proposed a novel model combining explicit and implicit feedback to address such a limitation. This study treats the average ratings of customers and products as the features of customers and products and converts them into a high-dimensional feature vector. Then, this study combines ID embedding vectors and feature vectors in the embedding layer to learn the customer-product interaction effectively. To evaluate recommendation performance, this study used the MovieLens dataset to conduct various experiments. Experimental results showed the proposed model outperforms the state-of-the-art. Therefore, the proposed model in this study can provide an enhanced recommendation service for customers to address the information overload problem.

• 풍력에너지저널
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• 제2권1호
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• pp.90-96
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• 2011

The purpose of this paper is to describe the control system for optimal performance of 2MW gearless PMSG wind turbine system, and to afford some techniques of the algorithm selection and design optimization of the wind turbine control system through analysis of load calculation and control characteristic. Wind turbine control system is composed of the main control system and remote control and monitoring system. The main control system is industrial PC based controller, and the remote control and monitoring system is a server based computer system. The main control system has a supervisory control of the wind turbine with operation procedures and power-speed control through the torque control by pitch angle. There are some applications to optimize the wind turbine system at the starting mode with increasing of rotor speed, and cut-in operating mode to prevent trundling cut-in and cut-out, a gain scheduling of pitch PID controller, torque scheduling and limitation of generation power by temperature limitation or remote command by remote control and monitoring system. Also, the server operation program of the remote control and monitoring system and the design of graphical display are described in this paper.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제27권2호
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• pp.157-173
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• 2024

Researchers continue to emphasize the centrality of proof in the context of school mathematics and the importance of proof to student learning of mathematics is well articulated in nationwide curricula. However, researchers reported that students' performance in proving tasks is not promising and students are not likely to see the need to prove a proposition even if they learned mathematical proof previously. Research attributes this issue to students' tendencies to accept an empirical argument as proof for a mathematical proposition, thus not being able to recognize the limitation of an empirical argument as proof for a mathematical proposition. In Korea, there is little research that investigated high school students' views about the need for proof in mathematics and their understanding of the limitation of an empirical argument as proof for a mathematical generalization. Sixty-two 11^th graders were invited to participate in an online survey and the responses were recorded in writing and on either a four- or five-point Likert scale. The students were asked to express their agreement with the need of proof in school mathematics and to evaluate a set of mathematical arguments as to whether the given arguments were proofs. Results indicate that a slight majority of students were able to identify a proof amongst the given arguments with the vast majority of students acknowledging the need for proof in mathematics.

• 기술혁신학회지
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• 제18권4호
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• pp.590-620
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• 2015

우리나라의 국가연구개발사업 투자규모와 연구성과의 양적수준은 증가하고 있으나, 성과활용 실적은 저조한 상황이다. 따라서 국가연구개발사업의 사업화에 영향을 미치는 요인에 관한 체계적인 파악과 분석은 매우 중요하다. 다만 선행연구들은 객관적인 데이터기반의 분석이 아닌, 주로 질적 연구를 중심으로 이루어져왔고, R&D투입요소와 산출물 간의 영향요인을 분석하는데 집중되어 왔다. 이에 본 연구에서는 부품소재산업경쟁력향상사업을 사례로 하여 국가연구개발사업의 연구성과, 연구주체유형, 정부지원규모, 과제유형, 연구자의 역량, 기술분야가 사업화에 미치는 영향에 대하여 객관적인 데이터를 기반으로 체계적으로 분석하고자 하였다. 분석결과, 특허성과와 정부지원규모, 기술분야 등의 요인들이 사업화성과에 영향을 미치는 것으로 나타난 반면, 논문성과와 연구수행주체유형, 과제유형, 연구자의 과제수행능력은 통계적으로 유의한 결과를 드러내지 못하였다. 따라서 향후 부품소재산업경쟁력 향상사업을 포함하여 국가R&D사업의 과제기획, 추진과정, 과제평가 등에서 사업화성과를 높이기 위해서는 투입과 결과 간의 인과관계를 보다 분석적으로 파악하여 과학적인 연구개발프로젝트 설계를 시도해야 할 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.51-56
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• 2005

It does not find for solution by limitation of technological mechanism of existent of leakage maintenance material. So, it is paid for huge expense because continuous repeat maintenance work is consisting. Furthermore, it is indicated by big problem in construction work that is constructed by field experience that thing by definite and systematic theory is not with proper performance test and analysis up to now. Therefore, wish to measure physical performance change by various environment condition maintenance of structure and performance construction work aspect in that apply to water leakage maintenance material using of acrylic resin system water expansion, leakage maintenance material in this research, and present suitable form of construction work under these environment. also, wish to ready diversified remedy by oversea market opening.