• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.222-223
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• 2014

According to the improvement of IT technology, an enhanced efficiency of management system in the construction industry is expected since a quotation system with BIM (Building Information Modeling) technique effectively estimates construction materials. For an enhanced efficiency of management system, related guidelines, standards, and manuals based on BIM are required, but the lack of this information causes difficulty to utilize in practice. In the paper, the satisfaction analysis was performed in order to promote the completeness of construction estimating manager that can be presented criteria and details of BIM-based quantity-takeoff, classification criteria.

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.221-227
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• 2004

This study develops a improved gate assignment algorithm and decision support system using its algorithm to extract a assignment result minimizing a walking distance of passengers in airport and maximizing the utilization rate of avaliable gates in domestic airports. By operation support system, it may contribute greatly in efficient enlargement of airport operation and increase the airport reliability through quickly coping with takeoff and landing delay of flight due to weather change, preservation and repair of gate, etc. Also, passengers who use airport terminal can minimize time and walking distance for departure, arrival, and transit, and it may greatly reduce the additional operation cost for common gates through maximizing the utilization rate for exclusive usage gates for airplanes which use gates.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.141-142
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• 2018

현재 시중에 판매되는 비행체들은 수동으로 조종을 하고 조종법이 미숙한 사람들은 다루기 힘들며 레저용으로 짧은 비행거리를 가지고 있고 간단한 영상촬영, 지형측정 등의 간단한 용도를 가졌다. 본 연구에서는 무인기의 FC(Flight Controller)의 인터페이스를 이용한 원리, 동작을 통하여 사용자의 조종 능력 향상을 기대할 수 있으며 Arduino 와 Pixhawk를 이용한 수직 이착륙기를 제작하여 활주로에 대한 제약을 없애고 멀티콥터와 비교하여 보다 좀 더 효율적인 비행을 할 수 있고자 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.93-96
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• 2010

현재 국내외에서 Building Information Modeling을 적용한 여러 분야의 연구가 활발하게 진행되고 있으며, 일부 국외에서는 3D 기반의 견적을 실제 프로젝트에 반영하고 있다. 반면, 국내 건설 프로젝트에서는 여전히 2D 설계도면과 물량산출 프로그램을 이용하여 견적이 이루어지고 있다. 작업의 신속성 및 정확성을 중요시하는 국내 견적 문화에서는 3D 기반의 물량산출 방식 도입을 부정적으로 바라보는 시각이 있으나, 향후 건설 산업의 경쟁력 확보를 위해서 3D 기반 견적작업이 필요하다. 이에 국외에서 상용화된 견적 시스템을 국내 건설 프로젝트에 적용한 결과, 몇 가지 한계점이 있는 것으로 드러나 국내 견적 방식에 적합한 3D기반의 물량산출 프로그램 개발이 절실한 상황이다. 따라서 본 연구에서는 국내 건설 산업에서의 물량 산출 특성을 반영한 공법기반 견적자동화 시스템 개발 및 검증을 통해 국내 3D 기반의 견적 도입을 앞당기고자 한다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.668-673
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• 1994

The paper presents a simple method for calculating the sound exposure level (LAE) of helicopter noise. It is assumed that a helicopter is a nondirective point source and that A-weighted sound pressure level at an observation point can be expressed by an A-weighted power level and a simple function of the distance from the helicopter. We derived a formula for LAE by integrating the sound energy along a finite or an infinite flight segment. The values calculated form the formula agree well with the results of test flights in which three types of helicopters each were operated in three moving modes of approach, takeoff and level flyover.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.39-44
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• 2011

An experimental method, based upon wall visualizations, has been developed to observe air flow near a plane wall around a row of five $45^{\circ}$ inclined jets discharging into a cross stream. This study concerns the variation of injection rate R which is one of the most important parameters governing this flow type. The Results are concentrated on the spatial evolution of two lobes with R. These structures are fastened to jets downstream edge and exist for very low injection rate values which are an indication of jets takeoff at the immediate downstream of injection orifices. The velocity rate of 0.42 marks a change in the structure alimentation system.

• Journal of KIBIM
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• v.10 no.4
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• pp.40-49
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• 2020

This report describes the development of a program that can be linked to an alignment and extracts related information using a prefab structured digital engineering model. The subject bridge was set as a straight alignment, the Superstructure type as Precast girder and the Substructure type as Precast pier and Cast-in-situ Abutment. We identified the variables required to create a digital engineering model and reviewed them to create the digital engineering model by entering them as numerical values in the program. In addition, it is configured so that the variables linked to the alignment can be entered numerically. The quantity takeoff can be calculated when the design is complete. The purpose of the program development presented in this report is to enable the designers to select the optimal alternative by designing a bridge that best fits their current situation, extracting the relevant information and then by providing it to the manufacturer and construction company.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.11-19
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• 2023

Drones, which were early operated by remote control, have evolved to enable autonomous flight by combining various sensors and software tools. In particular, autonomous flight of drones was possible since the application of GNSS-RTK (global navigation satellite system with real-time kinematic positioning), a precision satellite navigation technology. For instance, unmanned drone delivery based on GNSS-RTK data was demonstrated for pizza delivery in Korea for the first time in 2021. However, the vulnerabilities of GNSS-RTK should be overcome for delivery drones to be commercialized. In particular, jamming in the navigation system and low positioning accuracy in urban areas should be addressed. Solving these two problems can lead to stable flight, takeoff, and landing of drones in urban areas, and the corresponding solutions are expected to establish a hybrid positioning technology. We discuss current trends in hybrid positioning technology that can either replace or complement GNSS-RTK for stable drone autonomous flight.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.84-91
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• 2005

For long time, the takeoff and landing control of airship was worked by human handling. With the development of the autonomous control system, the exact controls during the takeoff and landing were required and lots of methods and algorithms were suggested. This paper presents the result of airship take-off and landing by buoyancy control using air ballonet volume change and performance control of pitch angle for stable flight within the desired altitude. For the complexity of airship's dynamics, firstly, simple PID controller was applied. Due to the various atmospheric conditions, this controller didn't give satisfactory results. Therefore, new control method was designed to reduce rapidly the error between designed trajectory and actual trajectory by learning algorithm using an artificial neural network. Generally, ANN has various weaknesses such as large training time, selection of neuron and hidden layer numbers required to deal with complex problem. To overcome these drawbacks, in this paper, the RBFN (radial basis function network) controller developed. The weight value of RBFN is acquired by learning which to reduce the error between desired input output through and airship dynamics to impress the disturbance. As a result of simulation, the controller using the RBFN is superior to PID controller which maximum error is 15M.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.145-153
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• 2007

The purpose of this study is to compare and analyze the phase-by-phase elapsed time, the COG, the body joint angle changes and the angular velocities of each phase of Handspring Salto Forward Piked performed by 4 college gymnasts through 3D movement analysis program. 1. The average elapsed time for each phase was .13sec for Phase 1, .18sec for Phase 2, .4sec for Phase 3, and .3sec for Phase 5. The elapsed time for Phase 1 to Phase 3 handspring was .35sec on average and the elapsed time for Phase 4 to Phase 5 handspring salto forward piked was .7sec on average. And so it showed that the whole elapsed time was 1.44sec. 2. The average horizontal changes of COG were 93.2 cm at E1, 138. 5 cm at E2, 215.7 cm at E3, 369.2 cm at E4, 450.7 cm at E5, and 553.1 cm at E6. The average vertical changes of COG were 83.1 cm at E1, 71.3 cm at E2, 78.9 cm at E3, 93.7 cm at E4, 150.8 cm at E5, and 97.2 cm at E6. 3. The average shoulder joint angles at each phase were 131.6 deg at E1, 153.5 deg at E2, 135.4 deg at E3, 113.4 deg at E4, 39.6 deg at E5, and 67.5 deg at E6. And the average hip joint angles at each phase were 82.2 deg at E1, 60 deg at E2, 101.9 deg at E3, 161.2 deg at E4, 97.7 deg at E5, and 167 deg at E6. 4. The average shoulder joint angular velocities at each phase were 130.9deg/s E1, 73.1 deg/s at E2, -133.9 deg/s at E3, -194.4 deg/s at E4, 29.4 deg/s at E5, and -50.1 deg/s at E6. And the average hip joint angular velocities at each phase were -154.7 deg/s E1, -96.5 deg/s at E2, 495.9 deg/s at E3, 281.5 deg/s at E4, 90.3 deg/s at E5, and 181.7 deg/s at E6. The results shows that, as for the performance of handspring salto forward piked, it is important to move in short time and horizontally from the hop step to the point to place the hands on the floor and jump, and to stretch the hip joints as much as possible after the displacement of the hands and to keep the hip joints stretched and high in the vertical position at the takeoff. And it is also important to bend the shoulder joints and the hip joints fast and spin as much as possible after the takeoff, and to decrease the speed of spinning by bending he shoulder joints and the hip joints quickly after the highest point of COG and make a stable landing.