• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1195-1201
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• 2010

Performance tests of a supersonic exhaust diffuser were conducted by using a liquid rocket engine for simulating high-altitude environment. The experimental setup consisted of a combustion chamber, a vacuum chamber and a diffuser. The combustion tests for simulating high-altitude environment were carried out at three cases by chamber pressure variation(26, 29, 32barg). The test results showed that the diffuser was started at all case and vacuum chamber pressures were approximately 140torr. The starting pressure using combustion gas was similar with that of cold gas, but the vacuum chamber pressure was relatively high because of high temperature in the vacuum chamber. The results of this test can be used as an essential database for the design of real-scale high-altitude simulation test facility in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1129-1136
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• 2021

A pan-tilt-zoom (PTZ) camera-based monitoring system for efficient monitoring in the engine room of a vessel was designed. A number of places exist where traditional analog instruments are still used in vessel engine rooms, and blind spots closely related to safety exist, for which flooding or fire is a concern. A camera-based monitoring system that guarantees a wide range at a relatively fast cycle for these monitoring points can be an effective alternative to enhance the safety of a vessel. Therefore, a multiview monitoring system is proposed in which the functions of the existing PTZ camera are further strengthened using a software. The monitoring system comprises four modules: camera control, location registration, traversal control, and multiview image reconstruction. The effectiveness of the method was evaluated through a series of experiments in an engine room environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.383-389
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• 2011

At the design stage, it is very important to know the ship maneuvering characteristics from the view point of ship performance and for the safety of navigation. IMO only gives some criteria for ships in full load even keel condition. However, the ship generally is operated not only in full load condition but also in half load condition or ballast condition. Therefore we must estimate the ship maneuvering in different loading condition to ensure that the ship will satisfy with IMO rules and navigate safely in every condition. In this paper, we have investigated the maneuvering characteristics of a ship by simulation and experiments with real ship. By comparing with the results of simulation, the real ship tests conform with simulation test and previous researches. Therefore, the method base on real data is well done to estimate the ship maneuvering in different loading conditions. The change of ship's manoeuverability accoriding to ship's operation conditions was estimated.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.111-117
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• 2012

Oscillating water column is the most widely used ocean energy converting systems all over the world. The operating performance is influenced by the efficiencies of the two converting stages in the OWC chamber-turbine integrated system. In order to consider the effects of the turbine, the orifice model are carried out. The VOF based Numerical Wave Tank (NWT) is utilized to simulate the water column oscillation inside the chamber and the results are compared with corresponding experimental data. This paper reviews the state of the art in interaction among wave elevation inside the chamber and air flow rate in the duct, which are considered the turbine effects. Effects of incident wave conditions and several shape parameters on the operating performance of OWC chamber are investigated numerically. The effects of the impulse turbine on the integrated system and interaction among the wave elevation, pressure and air flow velocities variations are investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.111-116
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• 2019

The fire detectors used in the engine rooms of ships offer only a slow response to emergencies because smoke or heat must reach detectors installed on ceilings, but the air flow in engine rooms can be very fluid depending on the use of equipment. In order to overcome these disadvantages, much research on video-based fire detection has been conducted in recent years. Video-based fire detection is effective for initial detection of fire because it is not affected by air flow and transmission speed is fast. In this paper, experiments were performed using images of smoke from a smoke generator in an engine room. Data generated using LBP and GLCM operators that extract the textural features of smoke was classified using SVM, which is a machine learning classifier. Even if smoke did not rise to the ceiling, where detectors were installed, smoke detection was confirmed using the image-based technique.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.303-308
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• 1997

전기설비에서 광범위하게 사용하고 있는 유압변압기는 연소성과 환경오염의 문제등으로 인하여 에폭시 수지를 주재로한 진공주형형 몰드변압기로 발전하였다. 따라서 현재는 건축물의 옥내에는 광범위하게 사용되고 있다. 본 논문에서는 에폭시 수지를 사용한 진공주형형 몰드변압기를 시료로 사용하여 전기실과 유사한 환경에서 연소시험에 의한 난연성과 자기소화성을 확인하여 몰드변압기로 인한 소화설비의 불필요성을 입증하였고, 청정소화 약제의 하나인 NAF S-III소화제로서 소화실험을 시행하여 그 소화시간을 측정하고 연소 시험의 결과와 비교 평가하였다. (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.98-99
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• 2001

B화력발전소 3호기의 배가스를 플라즈마를 이용한 탈황/탈질 동시처리기술에 적용하기 위하여 pilot-plant를 설치하고 실 배가스를 이용한 동시처리 실험을 시행하여 배가스 인입온도 $90^{\circ}C$에서 $NH_3$를 $SO_2$와 NOx에 대하여 0.65당량, $C_2$$H_4$를 NOx에 대하여 0.6 당량 주입하고 비전력량을 3～4 Whr/N㎥로 배가스에 인가하면, 탈황율 90%, 탈질율 70% 이상이 얻어지는 것을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.108-109
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• 2022

In this study analyzed experimental data on noise interference caused by engine operating apply surface wave communication in the engine room. For the experiment, 7 areas of the engine room on 256 ton tug boat and measured noise during engine on off using signal analyzer for effect surface wave communication. In order to construct and actual communication network based on the analysis of the noise and confirm the characteristics of surface wave communication in the area made metal bulkheads the actual communication network installed communication equipment between three metal bulkheads and conducted a comparative experiment with wireless communication. The difference was confirmed. As a result, in the case of surface wave communication, there was no significant difference in the transmission and reception rates before and after engine operation in an environment with three bulkheads, but in the case of Wi-Fi using wireless, the performance deteriorated significantly during operation. was confirmed. As a result of analyzing the experimental data, it was confirmed that noise caused by engine operation affects wireless communication but does not affect surface wave communication. Therefore, even in the area with a lot of electromagnetic wave noise in the ship, when the surface wave communication system is configured using the ship's metal structure, it is possible to replace the wireless communication and furthermore, it is possible to apply the surface wave communication in the enclosed space and the engine room in the ship.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.402-410
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• 2017

The effect of the steel pipe member joint on the design performance of a plastic multi-span greenhouse was analysed through the comparing full-scale experiment and numerical analysis. The design performance of the greenhouse is generally evaluated through numerical analysis, but it is rare to consider the characteristics of the connections or joints of the members. In this study, the effect of the column-gutter beam-rafter-wind break wall joint on the design performance of the whole structure of a plastic multi-span greenhouse was analysed. The numerical results with assuming that the member joint are rigid condition were compared with the full-scale load test results using member joints used in the field. The stiffness of the entire structure was compared using the load-displacement relationship and the change of the load sharing ratio that the main members such as column, rafters, and wind break wall was analysed. The results of the load test were about 40% larger than the numerical result and the member stress was more than twice as large as those of the loaded columns. In order to increase the reliability of the design performance of the greenhouse, it is necessary to develop a numerical analysis model which can consider the characteristics of various joints.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.476-481
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• 2019

Early detection of fire is an important measure for minimizing the loss of life and property damage. However, fire and smoke need to be simultaneously detected. In this context, numerous studies have been conducted on image-based fire detection. Conventional fire detection methods are compute-intensive and comprise several algorithms for extracting the flame and smoke characteristics. Hence, deep learning algorithms and convolution neural networks can be alternatively employed for fire detection. In this study, recorded image data of fire in a ship engine room were analyzed. The flame and smoke characteristics were extracted from the outer box, and the YOLO (You Only Look Once) convolutional neural network algorithm was subsequently employed for learning and testing. Experimental results were evaluated with respect to three attributes, namely detection rate, error rate, and accuracy. The respective values of detection rate, error rate, and accuracy are found to be 0.994, 0.011, and 0.998 for the flame, 0.978, 0.021, and 0.978 for the smoke, and the calculation time is found to be 0.009 s.