• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.241-249
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• 2017

This paper presents the design and evaluation of the optical system for an uncooled thermal-imaging camera. The operating wavelength range of this system is from $7.7{\mu}m$ to $12.8{\mu}m$. Through optimization, we have obtained a LWIR (Long Wave Infrared) optical system with a focal length of 5.44 mm, which consists of four aspheric surfaces and two diffractive surfaces. The f-number of the optical system is F/1.2, and its field of view is $90^{\circ}{\times}67.5^{\circ}$. The hybrid lens was used to balance the higher-order aberrations, and its diffraction properties were evaluated by scalar diffraction theory. We calculated the polychromatic integrated diffraction efficiency, and the MTF drop generated by background noise. We have evaluated the thermal compensation of a LWIR fixed optical system, which is optically passively athermalized to maintain MTF performance in the focal depth. In conclusion, these design results are useful for an uncooled thermal-imaging camera.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.376-381
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• 1992

This paper presents an expert system for the segmentation of a 2.5-D image. The results of two segmentation approaches, edge-based and region-based, are combined to produce a consistent and reliable segmentation. Rich information embedded in the 2.5-D image is utilized to obtain a view independent surface patch description of the image, which can facilitate object recognition considerably.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.117-126
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• 2003

This study was conducted to develop precision control system fur cold storage facility that could offer safe storage environment for green grocery. For that reason of neuro-fuzzy control system with learning ability algorithm and single chip neuro-fuzzy micro controller was developed for cold storage facility. Dynamic characteristics and hunting of neuro-fuzzy control system were far superior to on-off and fuzzy control system. Dynamic characteristics of temperature were faster than on-off control system by 1,555 seconds(123% faster) and fuzzy control system by 460 seconds(36.4% faster). When system was arrived at steady state. hunting was ${\pm}$0.5$^{\circ}C$ in on-off control system, ${\pm}$0.4$^{\circ}C$ in fuzzy control system, and ${\pm}$0.3$^{\circ}C$ in neuro-fuzzy control system. Hunting of humidity and wind velocity was also controlled precisely by 70 to 72.5% and 1m/s For storage experiment with onion, characteristics of neuro-fuzzy control system were tested. Dynamic characteristics of neuro-fuzzy control system made cold storage facility conducted precooling ability and minimized hunting.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.5
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• pp.612-620
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• 2015

Short-range detection of chemical agents deposited on ground surface using a standoff Raman system employing a pulsed laser at 248 nm is described. Mounted in a vehicle such as an NBC reconnaissance vehicle, the system is protected against toxic chemicals. As most chemicals including chemical warfare agents have unique Raman spectra, the spectra can be used for detecting toxic chemicals contaminated on the ground. This article describes the design of the Raman spectroscopic system and its performance on several chemicals contaminated on asphalt, concrete, sand, etc.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.640-652
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• 2007

The MM5, RAMS and WRF, meteorological models have provided the dynamical parameters as inputs to air quality model. A major content of this study is that significant characteristics of three models for high-ozone occurrence analyze for surface wind and air temperature fields and compare with observation data in Seoul metropolitan area. An analysis of air temperature field revealed that location of core in high temperature of MM5 and WRF differed from that of RAMS. MM5 and WRF indicated high temperature in Seoul but RAMS represented it on the outskirts of Seoul. MM5 and WRF were underestimated maximum temperature during daytime but RAMS simulated similar value with observation data. Surface wind field with three models, it was shown many differences at horizontal distribution of wind direction. RAMS indicated weak wind speed in land and strong sea breeze at coastal areas than MM5 and WRF. However wind speed simulated by three model were overestimated during both daytime and nighttime.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.83-89
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• 2010

This paper presents the impacts of Ultra Wide-Band(UWB) sensor using frequency of 4.5 GHz on Broadband Wireless communication system which uses frequency of 4.5 GHz. The Minimum Coupling Loss (MCL) method and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) is used to evaluate the interference effects of UWB sensor on Broadband Wireless communication system, respectively. The minimum protection distance between single UWB sensor and mobile station of Broadband Wireless communication system should be more than 1.2 m to guarantee the co-existence. In case of multiple UWB sensors, UWB transmitting PSD of around -68.5 dBm/MHz below should be required to guarantee interference probability of 5% below for mobile station of Broadband Wireless communication system.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.332-338
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• 2007

Yield mapping is necessary for precision farming. An on-site rice weighing system for a head-feed combine was developed to measure the total weight of rice grain harvested while the combine was operated. A load cell system was used to monitor rice weights accumulated into the combine grain tank using a load cell. This method gave cumulative grain weight readings as a function of time. The system consisted of a load cell, two supporting brackets, and a computer-based data acquisition system. The weights measured with the system from two fields were compared with those obtained with a commercially available electronic balance. The response of the load cell to varying grain weights was linearly modeled, showing a coefficient of determination of 0.998 and a standard error of ${\pm}4.09kg$.

• Journal of Power System Engineering
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• v.22 no.1
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• pp.5-10
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• 2018

In order to employ factorial design on electronically-controlled diesel engine, effects of 5 factors on specific fuel consumption, nitrogen oxides and carbon monoxide were examined by fractional and full factorial design in this research. There were different results between fractional and full factorial design, then effect of variables as ambient condition and measurement of fuel consumption were confirmed. It was shown that ambient condition affected uniformly trend of nitrogen oxides and carbon monoxide. However, both ambient condition and measurement of fuel consumption had nothing to do with trend of specific fuel consumption and therefore it must be careful to employ factorial design on specific fuel consumption as response.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.615-621
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• 2014

With development of electrical power system, the DC distribution system has been considered as a promising technology to be used in the future smart distribution system. Among the various components comprising the DC distribution system, the bi-directional DC/DC converter is one of the most important equipment to interconnect between main power system and various renewable resources such as photovoltaic power generation, wind power generation, and electrical vehicles. In this paper, a bi-directional DC/DC converter based on three-phases interleaved method which is effective to reduce ripple of input current and output voltage is modeled using ElectroMagnetic Transient Program(EMTP), and the verification of modeled bi-directional DC/DC converter is conducted.

• Proceedings of the KWS Conference
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• 2008.05a
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• pp.49-49
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• 2008