• Journal of Korean Society for Geospatial Information Science
• /
• v.24 no.1
• /
• pp.99-107
• /
• 2016

Korea has been known as volcanic disaster free area. However, recent surveying result shows that Baekdu mountain located in northernmost in the Korean peninsula is not a dormant volcano anymore. When Baekdu mountain is erupting, various damages due to the volcanic ash are expected in South Korea area. Especially, volcanic ash in the air may cause big aviation accident because it can hurt engine or gauges in the airplane. Therefore, it is a crucial issue to interrupt airplane navigation, whose route is overlapped with volcanic ash, after predicting three dimensional dispersion of volcanic ash. In this paper, we deals with 3D visualization techniques for volcanic ash dispersion prediction results. First, we introduce the data acquisition of the volcanic ash dispersion prediction. Dispersion prediction data is obtained from Fall3D model, which is volcanic ash dispersion simulation program. Next, three 3D visualization techniques for volcanic ash dispersion prediction are proposed. Firstly proposed technique is so called 'Cube in the Air', which locates the semitransparent cubes having different color depends on its particle concentration. Second technique is a 'Cube in the Cube' which divide the cube in proportion to particle concentration and locates the small cubes. Last technique is 'Semitransparent Volcanic Ash Plane', which laminates the layer, whose grids present the particle concentration, and apply the semitransparent effect. Based on the proposed techniques, the user could 3D visualize the volcanic ash dispersion prediction results upon his own purposes.

• Journal of Navigation and Port Research
• /
• v.39 no.6
• /
• pp.457-463
• /
• 2015

A gas turbine engine plays an important role as a prime mover that is used in the marine transportation field as well as the space/aviation and power plant fields. However, it has a complicated structure and there is a time delay element in the combustion process. Therefore, an elaborate mathematical model needs to be developed to control a gas turbine engine. In this study, a modeling technique for a gas generator, a PLA actuator, and a metering valve, which are major components of a gas turbine engine, is explained. In addition, sub-models are obtained at several operating points in a steady state based on the trial running data of a gas turbine engine, and a method for controlling the engine speed is proposed by designing an NPID controller for each sub-model. The proposed NPID controller uses three kinds of gains that are implemented with a nonlinear function. The parameters of the NPID controller are tuned using real-coded genetic algorithms in terms of minimizing the objective function. The validity of the proposed method is examined by applying to a gas turbine engine and by conducting a simulation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.381-381
• /
• 2019

동남아시아의 급격한 도시인구 증가는 도시화로 파생되는 제반문제를 유발하고 있으며 특히 집중호우와 홍수배제 시설의 부족 및 유관시설의 정보관리체계 부재는 홍수 피해규모를 가중시키고 있다. 인도네시아의 경우 물 재해 관리기관 간의 정보공유체계 부재로, 홍수로 인한 문제해결에 대하여 효과적인 대응이 어려운 실정이다. 주요 물 관리 기관인 유역관리청(BBWS)의 경우 조기홍수경보시스템을 보유하고 있으나 단순 수문현황 모니터링에 국한되어 운영되고 있다. 이에 본 연구에서는 홍수피해를 최소화 할 수 있는 동남아시아 맞춤형 물 재해 관리 클라우드 플랫폼을 개발하여 비구조적 홍수 문제해결의 매개체로 활용하고자 한다. 기본적인 유역 수문현황 모니터링과 함께 댐, 보, 배수문 및 펌프장 등 홍수방어시설물의 운영현황 정보, 홍수상황분석, 홍수위험지도 등 종합적인 물 재해 정보를 제공하고 사전에 홍수위험 지역을 분석하여 유관기관과 공유할 수 있는 물 재해 관리 의사결정지원시스템을 개발하고자 한다. 기본적인 정보관리 체계화를 위하여 인도네시아의 다양한 물 재해 관련기관에서 보유하고 있는 자료들의 통합 클라우드 DB관리 시스템을 구축하였다. 연구대상지역은 인도네시아 수도인 자카르타의 Pesanggrahan유역과 인근 Batam섬 Baloi유역을 선정하였으며 대상 유역의 수문, 기상자료 및 GIS 정보수집은 공동연구기관인 인도네시아 공공사업부 수자원청(MPWH)과 주요 물 관리기관인 유역관리청(BBWS)의 협조를 통하여 진행하였다. 수집된 자료들은 관계형 데이터베이스 관리시스템인 MySQL을 사용하여 통합 물 재해 정보 데이터베이스를 구축하였으며 완성된 데이터베이스의 정보제공 및 공유시스템은 웹기반 인터페이스를 통해 관리되도록 설계하였다. 홍수유출 해석을 위한 분석 엔진은 K-water의 홍수분석 시스템인 FAS를 이용하였다. FAS의 홍수분석모형인 COSFIM과 수리모형인 Fldwav를 연계하는 데이터 분석 플랫폼을 완성하였으며 인도네시아 현지 조건에 부합하는 홍수분석 시스템으로 Customizing과정을 수행하였다. 또한 FAS의 PC기반 시뮬레이션 형식을 DB 연계형 웹서비스 방식으로 연동되도록 개량하였으며 추후 SaaS형 물 재해 분석시스템으로 전환할 수 있는 개발환경을 확보하였다. 개발된 물 재해 분석 플랫폼(WRMP)을 활용하여 인도네시아 공동연구기관과의 협의를 통해 물 재해 관리 시나리오를 수립하고 그 대안을 제시하였으며, 적용 시나리오별 홍수피해 저감 효과를 분석하였다. 또한 향후 방재시설물까지 연계하여 운영효과를 분석할 수 있도록 구조화하였다. 개발된 물 재해 관리 시스템은 개선된 정보처리 및 분석시스템을 활용하여 종합적인 물 재해정보를 제공하고, 사전에 홍수위험 지역을 분석하여 유관기관과 공유할 수 있는 물 재해 관리 의사결정 지원시스템으로써 유용하게 활용될 수 있을 것이다.

• Journal of agriculture & life science
• /
• v.53 no.4
• /
• pp.113-124
• /
• 2019

In this study, the operational characteristics of a cam-type vegetable transplanter which usually used in domestic was analyzed and operating mechanism of a transplanting device was analyzed. The main components and power path of the transplanter were analyzed. The maximum and minimum control cycles according to the moving speed and the plant spacing were analyzed. 3D modeling and simulation were performed to derive the trajectory of the bottom end of the transplanting hopper and the plant spacing at the each operating condition. The simulation results were verified by the field tests. As main findings of this study, the transplanting device has one degree of freedom (DOF) which consist of 13 links, 17 rotating joints and 1 half joint, and each part has composite structure with cam and links. By continuous and repetitive motion of the structures of transplanting device, the transplanting hopper plants the seedling in the ground with a vertical direction, and the seedling was planted stably. The power is transmitted to the driving part and transplanting device from the engine, and the maximum and minimum plant spacing of the transplanting device were about 900 mm and 350 mm, respectively.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.2
• /
• pp.214-224
• /
• 2024

Sonobuoys are disposable devices that utilize sound waves for information gathering, detecting engine noises, and capturing various acoustic characteristics. They play a crucial role in accurately detecting underwater targets, making them effective detection systems in anti-submarine warfare. Existing sonobuoy deployment methods in multistatic systems often rely on fixed patterns or heuristic-based rules, lacking efficiency in terms of the number of sonobuoys deployed and operational time due to the unpredictable mobility of the underwater targets. Thus, this paper proposes an optimal sonobuoy placement strategy for Unmanned Aerial Vehicles (UAVs) to overcome the limitations of conventional sonobuoy deployment methods. The proposed approach utilizes reinforcement learning in a simulation-based experimental environment that considers the movements of the underwater targets. The Unity ML-Agents framework is employed, and the Proximal Policy Optimization (PPO) algorithm is utilized for UAV learning in a virtual operational environment with real-time interactions. The reward function is designed to consider the number of sonobuoys deployed and the cost associated with sound sources and receivers, enabling effective learning. The proposed reinforcement learning-based deployment strategy compared to the conventional sonobuoy deployment methods in the same experimental environment demonstrates superior performance in terms of detection success rate, deployed sonobuoy count, and operational time.

• Journal of the Korea Computer Graphics Society
• /
• v.30 no.3
• /
• pp.179-188
• /
• 2024

Recently, unmanned terminals (kiosks) have greatly increased their scope of use by allowing orders or payments to be made efficiently while replacing existing manpower. With the acceleration of digital transformation, the rate of kiosk installations has soared, making it an important task to help all age groups easily use kiosks. In this study, based on the function of the game engine and Hand Tracking technology, we developed content that can conduct kiosk education in a virtual world. The goal of this content is to help users unfamiliar with kiosks confidently cope with real-world situations by experiencing visual and auditory stress caused by waiting guests in virtual reality. To this end, two VR contents were developed. One is a simple kiosk experience content, and the other is specialized content that causes visual and auditory stress. The experiment was divided into two groups: one group experienced general VR content, while the other group experienced specialized VR content. After the experience, both groups proceeded to place orders in an actual store. Survey results showed that 85% of the experimental group and 95% of the control group were satisfied with the training. This confirms that the specialized experience described in this paper is effective for kiosk education.