• Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.253-260
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• 2015

Feature-based NC machining, which requires high quality of 3D CAD model, is widely used in machining aircraft structural part. However, there has been little research on how to automatically detect the CAD model errors. As a result, the user has to manually check the errors with great effort before NC programming. This paper proposes an automatic CAD model errors detection approach for aircraft structural part. First, the base faces are identified based on the reference directions corresponding to machining coordinate systems. Then, the CAD models are partitioned into multiple local regions based on the base faces. Finally, the CAD model error types are evaluated based on the heuristic rules. A prototype system based on CATIA has been developed to verify the effectiveness of the proposed approach.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.195-197
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• 2012

최근 고객관리 서비스는 사용자의 환경 및 특성까지 분석하여 개인에게 가장 적합한 서비스를 제공하는 형태로 변화하고 있다. 하지만 기존 고객관리시스템은 회원 가입 시 작성하는 정보 이외에 추가적으로 고객에 관한 정보를 얻기 위한 방법이 한정적이다. 이러한 기존의 고객관리 시스템은 고객의 성향에 따른 다양한 형태의 서비스를 제공하지 못하고 있다. 본 연구에서는 무선 통신 방법인 NFC(Near Field Communication)를 이용하여 고객의 성향을 신속하게 파악하며 분석할 수 있는 고객관리 시스템을 개발 제안한다. 제안된 시스템의 특징은 데이터의 처리 및 전송 경로가 사용자정보를 직접 서버로 전송하게 되며, 정보를 관리 서버에서 범주별로 분류하여 속성 단위로 가중치를 적용하여 분해하는 기능을 제공한다. 개발된 서버에서는 범주별로 규정되어 있는 속성정보에 대해 가중치와 저장된 사용자 정보를 제공된 알고리즘에 따라 상황인식기반으로 내용을 분석하게 되고, 분석된 사용자 정보들의 결과 값이 가장 높은 값을 가진 범주를 사용자의 특성으로 제공한다. 본 시스템으로부터 추출된 예측된 값은 사용정보를 수신할 때마다 갱신이 가능함으로 개발된 시스템은 사용자의 동향을 이용한 서비스를 온라인으로 제공할 수 있게 된다.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.551-554
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• 2008

An improved HPLC method for the separation of madecassoside isomers (madecassoside and asiaticoside-B) has been developed. The isomers can be separated with high resolution from extracts of Centella asiatica by HPLC using $\beta$-cyclodextrin as a mobile phase added on a $C_{18}$ column. The result shows that the isomers can be separated with a mobile phase consisting of methanol:water (50:50, v/v) with 4 mmol/L $\beta$-CD. To elucidate the mechanism of the separation of madecassoside and asiaticoside-B, this paper studied the separation of their aglycon parts (madecassic acid and terminolic acid), another pair of isomers. The isomers can also be separated with high resolution with a mobile phase consisting of methanol:water (65:35, v/v) with 4 mmol/L $\beta$-CD and the pH of the mobile phase was adjusted to 4. The paper also studied the separation of the two isomers by HPLC using $\alpha$-CD and Glucosyl-$\beta$-CD as a mobile phase additive in order to elucidate the mechanism of the separation process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.99-101
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• 2014

불안정한 네트워크 환경 문제를 해결하기 위해 제안된 Delay Tolerant Network(DTN)에서는 안정적인 통신을 위해 저장 및 전달(store-carry-forward) 방식의 라우팅 프로토콜을 사용한다. 이중 노드의 속성 정보를 이용하여 추후 네트워크 상황을 예측하고 라우팅을 하는 예측 기반 라우팅 프로토콜은 GPS와 같은 위치 서비스의 발전으로 인해 DTN에 효과적으로 적용 될 수 있다. 이러한 예측 기반 라우팅 프로토콜에서는 중계 노드의 효율성이 네트워크의 상황에 따라 달라지기 때문에 위치 서비스를 통해 받는 노드의 속성 정보를 분석하는 연구가 제시되어야 한다. 본 논문은 노드의 속성 정보를 네트워크의 환경 정보에 따라 분석하여 효율적인 중계 노드를 선택하는 알고리즘을 제안한다. 제안하는 알고리즘은 노드의 속도, 방향, 위치 등의 속성 정보를 네트워크의 정보에 따라 가중치를 두어 다양한 네트워크 환경에서 더 효율적인 노드를 선택할 수 있도록 한다. 본 논문은 제안하는 알고리즘을 사용한 라우팅 프로토콜이 기존 라우팅 프로토콜에 비해 전송률, 지연시간, 오버헤드 측면에서 향상됨을 검증한다.

• Journal of the Korea Convergence Society
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• v.2 no.3
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• pp.7-14
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• 2011

This paper deals with the efficient management for the intelligent distribution system related with the renewable energy sources, using the wire-wireless monitoring and control device. This device is mainly composed of 2 sections. One is monitoring device with the Autobase S/W and the other is control device using PLC. This paper proposes a wire and wireless monitoring and control device which can monitor and control the 50Kw PV system installed remotely (about 1Km) in the campus of the Korea University of Technology and Education. By the analysis of PV output characteristic using the device proposed in this paper, it is confirmed that the device can contribute the maintenance of PV system and also the establishment of Smart Grid.

• Steel and Composite Structures
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• v.34 no.6
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• pp.837-851
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• 2020

This study aims to examine the interface shear behavior between precast high-strength concrete slabs with pockets and steel beam to achieve accelerated bridge construction (ABC). Twenty-six push-out specimens, with different stud height, stud diameter, stud arrangement, deck thickness, the infilling concrete strength in shear pocket (different types of concrete), steel fiber volume of the infilling concrete in shear pocket concrete and casting method, were tested in this investigation. Based on the experimental results, this study suggests that the larger stud diameter and higher strength concrete promoted the shear capacity and stiffness but with the losing of ductility. The addition of steel fiber in pocket concrete would promote the ductility effectively, but without apparent improvement of bearing capacity or even declining the initial stiffness of specimens. It can also be confirmed that the precast steel-concrete composite structure can be adopted in practice engineering, with an acceptable ductility (6.74 mm) and minor decline of stiffness (4.93%) and shear capacity (0.98%). Due to the inapplicability of current design provision, a more accurate model was proposed, which can be used for predicting the interface shear capacity well for specimens with wide ranges of the stud diameters (from13 mm to 30 mm) and the concrete strength (from 26 MPa to 200 MPa).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1032-1038
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• 2017

Recently, regulation on carbon emissions has been strengthened according to the new climate change convention (COP21) held in Paris, and then Korea has decided to reduce CO2 emissions by 37% until 2030. As one of countermeasures, the government has energetically performed demonstration projects of island micro-grid including solar power, wind power and energy storage system. However, in order to smoothly introduce island micro-grid, it is a critical issue to carry out the economic evaluation for power utility aspect and independent power producer aspect. Therefore, this paper proposes economic evaluation algorithms of island micro-grid which are based on the present worth method, considering cost and benefit factors in the aspect of both sides. Firstly, in case of power utility this paper proposes algorithm to estimate a period of return on investment according to the introduction capacity of distributed generators replacing diesel generator. And also, in case of independent power producer, this paper proposes evaluation algorithm to estimate weighting factor of SMP and benefit rate based on break-even point related with cost and benefit. From a case study result on real island micro-grid model, it is confirmed that proposed algorithms are useful and practical for the economic evaluation of island micro-grid.

• Journal of Agricultural Extension & Community Development
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• v.10 no.1
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• pp.31-42
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• 2003

The purposes of this study were (1) to identify the present situation and pending problems of agricultural education in Agricultural Technology & Extension Center (ATEC), (2) to analyze the satisfaction degree and educational needs of agricultural extension education program, and (3) to draw some implications in the direction of the development direction of agricultural extension, based on the analysis aforementioned. Data were collected through questionnaires from 230 farmers. Based on the results of study, the recommendations were as follows. 1. Increase of income could not guarantee the improvement of QOL. So, ATEC should make some efforts to plan and administer diversified agricultural extension and education programs. 2. Agricultural practice was the most effective educational methods. Especially, for return-migrants and young farmers, applicable educational program should be planned and offered. 3. Education program on agricultural information, especially on the internet use, would be the most attractive program of agricultural extension education in the future.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.551-556
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• 2023

The study is to analyze the success strategies of the Cooperative Integrated Arts Activities in Seoul and to explore ways to implement it to the local public school. According to research, Cooperative Integrated Arts Activities fulfill the purpose of providing universal arts education by being implemented in the school curriculum. They are also characterized by active administrative and financial support and interactive participatory arts education with assured diversity. Therefore, when applying to a local public school, it is necessary to consider factors such as active administrative support, sustainable allocation of human and material resources, customized arts education that engages the all students and reflects their unique characteristics, social distribution through sharing, and continuous monitoring.

• Women's Health Nursing
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• v.30 no.3
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• pp.192-202
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• 2024

Purpose: This study aimed to explore the significance and insights derived from the experiences of pregnant women in Korea who participated in online prenatal education during the COVID-19 pandemic. Methods: This study employed the hermeneutic phenomenology framework developed by Colaizzi. It involved 12 pregnant women who participated in online prenatal education provided by public health centers in Chuncheon, Korea. Data collection was achieved through in-depth interviews conducted in Korea from October 2021 to April 2022. Results: In total, 51 significant statements were extracted from the interview data and then categorized into 10 themes. Finally, three categories were formed by merging similar themes. The three basic categories of participants' experiences of online prenatal education were "feeling of safety and comfort in body and mind," "frustrated by a lack of interaction," and "digital education being a double-edged sword." Pregnant women expressed ambivalence regarding the benefits and drawbacks of the online educational experience. They desired more interactive and practical learning opportunities, even as they appreciated the comfort of learning remotely. Conclusion: This study revealed the phenomenon of online prenatal education as an advanced form of distance-based prenatal education instead of the traditional in-person classroom. To maximize the educational effectiveness of this new format, public health center policies must address the digital literacy gap and enhance accessibility by leveraging the immersive multimedia experiences that online education offers to pregnant women. We recommend that maternal healthcare providers adopt this innovative approach to prenatal education, utilizing distance education technology to improve participation and promote immersion.