• Journal of the Korean earth science society
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• v.41 no.6
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• pp.658-669
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• 2020

The horizontal-to-vertical spectral ratio (HVSR) analysis is conducted to estimate the site amplification effect and the thickness of the sedimentary layer beneath the measurement site. We investigated the effects of meteorological variations (wind and precipitation rate) and sensor burial depths on HVSR analysis. The HVSR results were unstable when seismographs were exposed on the ground. The HVSR results of ambient noise data measured under strong winds were also unstable. It is recommended to measure the ambient noise at wind speeds of <3 m s-1. Stable HVSR results were obtained when seismographs were buried, regardless of the precipitation rates. The results of this study provide the best observations and optimal weather conditions required to acquire accurate and reliable HVSR results.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.21-27
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• 2023

Modern naval ships install an Infra-Red Signature Suppression system (IRSS) in their exhaust pipe to reduce infrared signature emitted to the outside. In addition, naval ships are strategic assets with a very long life cycle, so high reliability of the performance of the equipment on board must be guaranteed. Therefore, equipment such as IRSS is evaluated for performance through model testing at the design stage. A variety of measuring instruments are used in IRSS model testing, and the reliability of these instruments must also be guaranteed. In this paper, a study was conducted to evaluate the reliability of measurement equipment used in IRSS model testing. The test equipment and instruments used were a hot gas wind tunnel, pitot tube, digital differential pressure gauge, thermocouple sensor, and digital recorder. As the fan speed of the hot gas wind tunnel increased, the measurement deviation of the flow decreased, and the temperature output of the thermocouple sensor showed differences in response time and stability depending on the method used.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1009-1014
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• 2023

Comprehensive observations of the Euler method and the Lagrangian method were performed in order to obtain high-resolution observation data in space and time for the complex environment of new city. The two radiosondes, which measure meteorological parameters using Lagrangian methods, produced air pressure, wind speed and wind direction. They were generally consistent with each other even if the observation points or times were different. The temperature measured by the sensor exposed to the air during the day was relatively high as the altitude increased due to the influence of solar radiation. The temporal difference in wind direction and speed was found in the comparison of Euler's wind profiler data with radiosonde data. When the wind field is horizontally in homogeneous, this result implies the need to consider the advection component to compare the data of the two observation methods. In this study, a method of using observation data at different times for each altitude section depending on the observation period of the Euler method is proposed to effectively compare the data of the two observation methods.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.11 no.1
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• pp.41-55
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• 2003

A calibration jet system using separate blower is developed to calibrate a flow sensor effectively. Designed open circuit type mini calibration jet system, which has the dimension of $0.5m(W){\times}1.17m(H)$ is small compared with conventional calibration jet systems. The exit of nozzle has exchangeable contractions with a cross section area of $38.5cm^2$ , and a cross section area of $113.1cm^2$, respectively. The ranges of wind speed at exit of exchangeable nozzles are $7.5{\sim}42\;m/s$ and $1.8{\sim}16.5\;m/s$, respectively. The input power for the high pressure blower is 1.18kW. The turning vanes for corner was rolled flat plate parallel to the flow direction. The flow conditioning screen was located immediately downstream of the wide-angle diffuser. The honeycomb and two flow conditioning screens were located in the stagnation chamber. From the economical point of view and the simplicity of the calibration jet system set up and handling, it can be said that the developed calibration jet system is an effective calibration jet system. This system can also be used to calibrate the flow sensor with high resolution.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.1011-1019
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• 2018

Existing exploration robot is able to control its speed using technologies such as the remote control and deep learning. However its speed control method using weather information has not been proposed. To overcome the problem of conventional methods without using the weather information which is an useful ordinary life information, this paper proposes a new speed control method of exploration robot using weather information gathered from RSS service which is offered without cost by the Meteorological Agency. The exploration robot implemented in this paper is controled by the remote control through the TCP/IP communication and provides real-time real spot figure gathered from its camera sensor within the range of WiFi. Additionally, according to the weather information from URL of the Meteorological Agency, the implemented exploration robot autonomously controls it speed. The correct performance of the proposed method is verified by the experimental measurement data of its speed according to the precipitation probability and wind speed in this paper.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.156-162
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• 2020

Wireless Sensor Network (WSN) field is mainly studied to monitor and characterize large-scale physical environments to track various environmental or physical conditions, such as temperature, pressure, wind speed and humidity. WSN can be used in various applications such as wild surveillance, military target tracking and monitoring, dangerous environmental exploration and natural disaster relief. We design probabilistic mobile models that apply to mobile ad hoc network mobile environments. A probabilistic shift model proposed by dividing the number of moving nodes and the distance of travel into two categories to express node movement characteristics. The proposed model of movement through simulation was compared with the existing random movement model, ensuring that the width and variation rate of the first node node node node (FND) was stable regardless of the node movement rate. In addition, when the proposed mobile model is applied to the routing protocol, the superiority of network life can be verified from measured FND values. We overcame the limitations of the existing random movement model, showing excellent characteristics in terms of energy efficiency and stable in terms of changes in node movement.

• Proceedings of the KSRS Conference
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• v.2
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• pp.997-1000
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• 2006

We estimate the net heat flux in the tropical and subtropical Atlantic Ocean using satellite data. These fluxes are related to changes in sea surface temperature (SST). This variable influences atmospheric circulations and is indicative of surface and subsurface oceanic circulations. We employ data from the geostationary METEOSAT-7 and 8 satellites and from the Special Sensor Microwave/Imager (SSM/I) for the shortwave and long-wave radiative fluxes, and for estimates of SST. For turbulent flux calculations, we use the bulk aerodynamic method with satellite estimates for wind speed and atmospheric humidity and temperature.

• Journal of the Speleological Society of Korea
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• no.81
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• pp.7-19
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• 2007

본 논문은 초음파센서와 적외선센서를 이용하여 그 신호를 받아 주 모터를 제어한 것으로, 센서를 이용한 선풍기의 풍향 및 풍속을 제어하였다. 풍향제어는 인체감지센서와 ATmega128, DC모터를 사용하였고, 기본적으로 WmAVR과 PonyProg를 사용하여 소스코딩 및 다운로딩을 하였으며, 모터 구동드라이버는 모터제어에 범용으로 쓰이는 L298 칩을 사용하였다. 풍속제어는 초음파센서와 ATmeBa16, DC모터를 사용하여 제작하였고, 풍향제어부와 마찬가지로 WinAVR과 PonyProg 및 L298 칩을 사용하여 소스코딩 및 다운로딩을 하였다. 풍향제어는 물체가 정면에 위치하면 회전을 멈추고, 좌우로 $100^{\circ}$ 반경이내에서 거리 1m내외의 물체를 감지하도록 설계하였다. 풍속제어는 물체까지의 거리를 최소 3cm 최대 3m 이내에서 물체를 감지하여 모터의 속도를 제어할 수 있도록 하였고, 모터속도는 DC모터를 PWM 방식으로 제어하여 속도를 조절하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.1
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• pp.44-54
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• 1993

This is an experimental study to identify the performance of air-to-air rotary heat exchanger with polyurethane foam matrix. The experimental apparatus including heating AHU(Air Handling Unit), cooling AHU, sensor chamber, and heat exchanger testing unit was designed and manufactured in this study. The performance of heat exchanger with porous polyurethane foam matrix was tested with variations of the density and the thickness of matrix, regulating the wind velocity and the rotational speed of matrix. The actual heat recovery effectiveness, air leakage rate, and pressure drop of heat exchanger were measured and analyzed.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.25-31
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• 2011

Recently NMEA 2000 protocol is familiarized as a standard real time instrument network of SOLAS ship. This paper is studied to develop NMEA 2000 based two-dimensional ultrasonic anemometer which is core device for navigation as a sensor of wind speed and direction using ultrasonic including temperature and barometer. Developed system is connected to NMEA 2000 network which is composed of various kinds of merchandised NMEA 2000 device such as depth gauge, speed gauge, GPS device etc. to test connectivity with other NMEA 2000 device and functional test are carried out as weather station in comparison with other merchandised weather station which are developed advanced foreign company to ascertain usability as a weather station on board.