• Smart Structures and Systems
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• v.20 no.5
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• pp.563-572
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• 2017

The safety of structures is closely associated with the structural out-of-plane behavior. In particular, long and slender beam structures have been increasingly used in the design and construction. Therefore, an evaluation of the lateral and torsional behavior of a structure is important for the safety of the structure during construction as well as under service conditions. The current contact measurement method using displacement meters cannot measure independent movements directly and also requires caution when installing the displacement meters. Therefore, in this study, a vision-based system was used to measure the in-plane and out-of-plane displacements of a structure. The image processing algorithm was based on reference objects, including multiple targets in Lab color space. The captured targets were synchronized using a load indicator connected wirelessly to a data logger system in the server. A laboratory beam test was carried out to compare the displacements and rotation obtained from the proposed vision-based measurement system with those from the current measurement method using string potentiometers. The test results showed that the proposed vision-based measurement system could be applied successfully and easily to evaluating both the in-plane and out-of-plane movements of a beam including twisting rotation.

• Publications of The Korean Astronomical Society
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• v.27 no.3
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• pp.87-93
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• 2012

A low-dispersion fiber feed Littrow-mounted grating spectrometer for education was designed and fabricated. The dispersion element is a reflective type blazed grating Edmundoptics NT 46-075 (spatial frequency 600 lines/mm, dimension $30mm{\times}30mm$, blazed angle 8.6 degree). The optical fiber coupler module for optical guiding from telescope to spectrometer is composed of a multi-mode FC connector - FC connector optical fiber patch cord (core/cladding diameter $50{\mu}m/125{\mu}m$) and two 1.25" throw-tube couplers. The lens for collimating and imaging is a general purpose focal length 50 mm camera lens (f/1.8). The device for optical path control is a rectangular prism (size $25mm{\times}25mm$). The imaging camera sensor is a Meade DSI Pro 2 CCD sensor (black and white, $752{\times}582$ pixels and pixel size $8.3{\mu}m{\times}8.6{\mu}m$). Softwares for data logging and analysis consist of Meade Autostar Suite, NIH imagej and Vernier Logger Pro 3. The wavelength coverage range of the spectrometer is 205 nm at central wavelength 550 nm. The wavelength resolution is 1.7 nm.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.11-17
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• 2009

Daylighting is core of sustainable design in most buildings. Well-designed daylighting systems can significantly reduce or even eliminate the electric lighting loads during the day time, including air conditioning energy loads. Among window systems. the topside lights systems including monitor lighting, sawtooth lighting, sunscoop and, lightscoop is one of the most popular apparatus to improve the lighting quantity. Also they are important both in terms of energy savings and visual quality. The objective of this study is to analyse daylighting performance of topside lighting system for different orientations. Four types of topside lighting system were tested and comparpd: monitor lighting, sawtooth lighting, lightscoop and sunscoop. Totally 25 measuring points of illuminance on the horizontal plane were monitored from 09:00 to 17:00 on October 6, 2008. Agilent data logger and photometric sensors Li-cor were used. Comparisons with a light factor is discussed. The results found in this study would mean that there were no significant differences in light factor between three cases.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.333-337
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• 2002

All the outdoor and indoor spaces are connected with each other. The human being moves toward those spaces and experiences temperature fluctuation between the natural and artificial temperature. We conducted an experiment which subjects are the college students wearing the data logger in urban life, and measured 24 hours' exposed temperature and thermal comfort in summer. Results were as follows. 1. Most subjects get weather information(84.6％). Fashion(46.2％) and weather (30.8％) are the reasons to select clothes. They spend their time in indoor environment for 84.92％ hours of a day and have an air-conditioner(61.5％) in their houses. 2. Exposed temperature fluctuation were from 33.8$^{\circ}C$ to 15.6$^{\circ}C$. The median value of experienced temperature were 26-27$^{\circ}C$ and average temperature was 26.3$^{\circ}C$. Subjects experienced cold shock of 3.96 times in a day and 67.21％ of all evaluated thermal comfort in the range of -1 and 1 by ASHRAE 7 Category Scales. Artificial environment which connected with outside let people experienced temperature fluctuation in wide range.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.879-884
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• 2007

This study is to observe the change of temperature and relative humidity for various vegetables in vacuum precooling system. The materials for experiments were the lettuce, chinese cabbage, pak choi and cabbage. The experimental apparatus was constructed of vacuum chamber, vapor/water separator, water tank, pumps ejecting and cooling water circulation, refrigerator unit, cooling coil for water cooling, Hygrometer and Data logger measuring of the temperature change. The experiments were operated in 20torr and recorded every 3 minutes. It was found that the cooling temperature and speed of vegetables are depending on the percentage of its water content. The more water contains, the faster cooling speed and the lower cooling temperature.

• Proceedings of the KIEE Conference
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• summer
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• pp.1367-1369
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• 2004

When an underground pipeline runs parallel with subway DC electrification system, it suffers from stray current corrosion caused by the stray current from the rails negative returns. Perforation due to the stray current corrosion may bring about disastrous accidents such even in cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Busan. In this paper, we report the real-time measurement data of the pipe-to-soil potential variation in the presence and absence of the IR compensation. The drainage current variation was also measured using the Stray Current Logger developed. By analyzing them, the problems of current countermeasures for stray current corrosion are discussed.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.71-75
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• 2010

This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by injection operating water to cooling plate. And at this experiment it used ethylene glycol-water solution and the concentration is 10 to 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank, brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring and a vertical circular tube with single copper plate as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 1.0 to 2.0m/s and the cooling temperature of $-17^{\circ}C$ to $-10^{\circ}C$.

• Journal of Institute of Convergence Technology
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• v.6 no.1
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• pp.7-11
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• 2016

An experiment was performed to show the bio-signal characteristics of the Stuckyi when was heated. To measure the bio-signal of the plant, this study used the electrode with copper(+) and constantan(-). The electrode was directly inserted into the Stuckyi stems. And used T-type thermocouple to measure the inside temperature of the Stuckyi. During the experiments, room temperature also measured with T-type thermocouple. Heating was made with hair dryer periodically that 3 times turned on for heating 5 min and off for non-heating 25 min. Under the situation, the responses of the Stuckyi including voltage potential and inside temperature were measured using data logger(HP-34970A) according to the distances(15cm, 30cm, 45cm) between hair dryer and the plant. Through the experiments, We knew that the inside temperature has similar level and behavior with the room temperature at normal state. And during heating period, the inside temperature and the potential were also simultaneously increased sharply. From the experiments, we revealed that the measuring system of bio-signal of the plant being proposed in this study can be useful to show the Characteristics of the plants.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.271-273
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• 2010

태양광발전시스템에서 PV모듈이나 어레이의 성능특성 및 성능추정이 요구되고 있다. 태양광 발전 모듈은 장기간 사용 시 환경 요인 등으로 효율이 나빠지며 어레이의 특정 모듈 효율저하는 전체 발전 전력의 감소를 초래하므로 실시간 감시가 필요하다. 이 논문은 태양광 발전 모듈의 발전 전력을 실시간으로 측정하기 위한 것이다. 모듈의 출력을 실시간으로 측정하기 위해 전압, 전류 측정 회로를 제작하고 온도, 일조량 측정 장치를 제작하여 RS485 통신으로 연결하였다. Visual Studio - Basic .Net(2005)과 NI사의 Measurement Studio를 이용하여 실시간 모니터링 프로그램을 제작하였고, 모듈들 사이의 상대적인 발전 출력을 비교하여 효율 저하가 의심되는 모듈을 실시간으로 탐색하였다. 20개 모듈의 직병렬로 구성된 1kW 태양광 발전체에 적용하여 시험한 결과 2개의 모듈에서 성능 저하가 의심되는 결과가 확인되었다.

• Computers and Concrete
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• v.28 no.5
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• pp.479-486
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• 2021

Reinforced concrete (RC) slabs are exposed to several static and dynamic effects during their period of service. Accordingly, there are many studies focused on the behavior of RC slabs under these effects in the literature. However, impact loading which can be more effective than other loads is not considered in the design phase of RC slabs. This study aims to investigate the dynamic behavior of two-way RC slabs under sudden impact loading. For this purpose, 3 different simply supported slab specimens are manufactured. These specimens are tested under impact loading by using the drop test setup and necessary measurement devices such as accelerometers, dynamic load cell, LVDT and data-logger. Mass and drop height of the hammer are taken constant during experimental study. It is seen that rigidity of the specimens effect experimental results. While acceleration values increase, displacement values decrease as the sizes of the specimens have bigger values. In the numerical part of the study, artificial neural networks (ANN) analysis is utilized. ANN analysis is used to model different physical dynamic processes depending upon the experimental variables. Maximum acceleration and displacement values are predicted by ANN analysis. Experimental and numerical values are compared and it is found out that proposed ANN model has yielded consistent results in the estimation of experimental values of the test specimens.