• Journal of the Korean Institute of Rural Architecture
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• v.8 no.1
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• pp.17-24
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• 2006

The purpose of this study is to provide the systematic report and analysis about Apartment VE application in Design Phase. In this study, the method of VE application is classified into foure groups-changing materials, changing a method of construction, acceptance of new technology, and use of new device. The facts found in this study can be summarized as follows. Application rate of VE is highest in building circumference parts. The main reason would be that there are many applicable factors according to locations, types of work, etc. Parking lots also show similar results with the same reason. It means there are a lot of possibility to adapt value engineering in these steps during the work. So far application of value engineering has been so limited that just small changes of process or method have been tried. One reason is the lack of challenging and the other is some characteristics of construction work which is very difficult to fix after completion. In the future, it would be more efficient to apply new technology and new device in construction work. Though these attempts have been ignored in Korea so far, there are still lots of possibilities to be developed in value engineering.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.522-524
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• 2018

A New Direct AC LED Driver has been proposed for wide output power range and precise constant current regulation using an advanced auto commutation topology. The conventional shunt regulation method provides a stepped input current shape by fixed regulation references in the linear regulator of the each channel, which results in poor current regulation and high THD. The conventional method needs to assign a linear regulator in each LED channel so that the number of linear regulator increases when extending the number of channels especially at high power application. The proposed regulation method can drive multiple switches to regulate each LED channel current by a single amplifier with sinusoidal reference so that large number of LED channel can be simply extended with less BOM cost and low THD is obtained with the accurate current regulation thanks to the sinusoidal input current control in the closed loop control. To confirm the validity of the proposed circuit, theoretical analysis and experimental results from a 20-W LED driver prototype are presented.

• Journal of Biosystems Engineering
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• v.42 no.2
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• pp.98-103
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• 2017

Purpose: Precision agriculture includes determining the right amount of nitrogen for a specific location in the field. This work focused on developing and validating a model using variable rate nitrogen application based on the estimated SPAD value from the ground-based image sensor. Methods: A variable rate N application based on the decision making system was performed using a sensor-based variable rate nitrogen application system. To validate the nitrogen application decision making system based on the SPAD values, the developed N recommendation was compared with another conventional N recommendation. Results: Sensor-based variable rate nitrogen application was performed. The nitrogen deficiency level was measured using the image sensor system. Then, a variable rate application was run using the decision model and real-ti me control. Conclusions: These results would be useful for nitrogen management of corn in the field. The developed nitrogen application decision making system worked well, when considering the SPAD value estimation.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.246-248
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• 2006

This paper presents a visualization application using 3D-graphics for effective maintenance of power equipments. The maintenance algorithm implemented in the application is based on Condition-Based Maintenance (CBM) and Reliability-Centered Maintenance (RCM). The main frame of the developed application was made up based on visual C++ (MFC). In order to develop the interactive 3D application, the WorldToolKit library based on Open GL was used. The developed application can help the power system operators to intuitively recognize the present state and maintenance information of the equipments.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.460-465
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• 2006

멀티미디어 Application의 QoS(Quality of Service) 를 보장하기 위해서 유선 망 에서도 종단간 자원을 예약하는 방법을 쓰거나 서비스 차등을 위해서 서비스 차등 클래스를 두어서 차등 서비스로 멀티미디어 Application의 QoS를 보장한다. 현재 광범위하게 퍼져 있는 무선 Network에서도 멀티미디어 Application QoS가 중요한 이슈 이고 유선망은 무선망과 달리 망 자체의 Error rate이 더 높기 때문에 더 민감하게 QoS를 보장 해야 할 것이다. 이 논문에선 무선망인 Cellular network에서 Application QoS를 보장하기 위해서 자원을 어떻게 활용할 것인지에 대한 방법을 제시하고자 한다.

• Journal of Multimedia Information System
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• v.8 no.4
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• pp.243-250
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• 2021

Instructional contents are used to demonstrate a technical process to teach and walkthrough certain procedures to carry out a task. This type of informational content is widely used for teaching and lectures in form of tutorial videos and training videos. Since there are questions and uncertainties for what could be the killer application for the novel wearables, we propose a self-instruction training application on a smart glass to utilize already-available instruction videos as well as public open data in creative ways. We design and implement a prototype application to help users train by wearing smart glasses specifically designed for two concrete and hand-constrained use cases where the user's hands need to be free to operate. To increase the efficiency and feasibility of the self-instruction training, we contribute to the development of a wearable killer application by integrating a voice-based user interface using speech recognizer, public open data APIs, and timestamp-based procedural content navigation structure into our proof-of-concept application.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.95-101
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• 2006

Present chemical application system using a power sprayer has been a labor intensive, ineffective and shirking task in farming. Therefore, a small RF controlled (unmanned) helicopter was suggested to replace the conventional spray system. The aerial application using the unmanned helicopter has been already utilized in Japan, where total area applied up to 704,000 ha in 2005. In this article, the status and cost analysis on the unmanned agricultural helicopter were studied. The aerial application using the agricultural helicopter helps precise and timely spraying and reduces labor intensity and pollution. The field capacity of the helicopter was found to be 60-70 ha a day. The break even point was estimated near the operating area of 750 ha annum. The development of an agricultural helicopter was necessary for taking advantages of both technique and economy.

• Journal of Engineering Education Research
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• v.25 no.2
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• pp.13-21
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• 2022

In many existing studies, the analyses on the application and effect of the project-based learning model (PBL), a student-centered teaching and learning strategy, have been emphasized and carried out in various majors and courses. This case study analyzes the effects of applying a project-based learning model to the engineering accounting course for engineering students in 2021 in the context of the COVID-19 pandemic, compared with the offline course in 2019 and the simple online course in 2020. Project team consisting of 2-3 students carried out online collaborative learning activities for solving open-ended problems through the 5-step PBL procedure including presenting the final result. Except for this online PBL application in 2021, textbooks, lecture contents, assignments, and tests were implemented the same for each semester for three years. Through lecture evaluation and survey by students, the online PBL application semester showed higher effects in inducing student-centered learning, lecture satisfaction, and student competency improvement compared to the non-applying semesters, further, it was evaluated that the online PBL application to the course and evaluation method were more appropriate than other semesters. It is expected that the online PBL method and operation procedure applied in this study can be utilized as a best practice for the design and operation of various online courses for student-centered collaborative learning activities and educational effects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.179-180
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• 2017

In order to improve the constructability of tall building construction, there is increasing needs to derive the design output by performing construction engineering at the design phase. It contributes to minimizing wastes such as design changes and reworks as well as improving project performance. Therefore, in this study, we analyzed the application period and participants for engineering tasks derived from a previous study, and then regrouped to efficiently reflect them at the design phase. Considering similarity of application period and attributes, the existing 22 engineering tasks, which were classified into 5 factors, were reclassified into 13 groups. The results of this study can be used as basic data for efficient construction engineering execution at the design phase.

• Coupled systems mechanics
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• v.8 no.2
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• pp.99-109
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• 2019

This work investigates the accuracy and performance of a $FE^2$ multi-scale implementation used to predict the behavior of composite materials. The equations are formulated assuming the small deformations solid mechanics approach in non-linear material models with hardening plasticity. The uniform strain boundary conditions are applied for the macro-to-micro transitions. A parallel algorithm was implemented in order to solve large engineering problems. The scheme proposed takes advantage of the domain decomposition method at the macro-scale and the coupling between each subdomain with a micro-scale model. The precision of the method is validated with a composite material problem and scalability tests are performed for showing the efficiency.