• 대한임베디드공학회논문지
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• 제17권1호
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• pp.33-40
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• 2022

With the recent increase in the development of military drones, they are adopted and used as the combat system of battalion level or higher. However, it is difficult to use drones that can be used in battles below the platoon level due to the current conditions for the formation of units in the Korean military. In this paper, therefore, we developed a program drones equipped with a thermal imaging camera and LiDAR sensor for reconnaissance and exploration that can be applied in battles below the platoon level. Using these drones, we studied the possibility and feasibility of drones for small-scale combats that can find hidden enemies, search for an appropriate detour through image processing and conduct reconnaissance and search for battlefields, hiding and cover-up through image processing. In addition to the purpose of using the proposed drone to search for an enemies lying in ambush in the battlefield, it can be used as a function to check the optimal movement path when a combat unit is moving, or as a function to check the optimal place for cover-up or hiding. In particular, it is possible to check another route other than the route recommended by the program because the features of the terrain can be checked from various viewpoints through 3D modeling. We verified the possiblity of flying by designing and assembling in a form of adding LiDAR and thermal imaging camera module to a drone assembled based on racing drone parts, which are open source hardware, and developed autonomous flight and search functions which can be used even by non-professional drone operators based on open source software, and then installed them to verify their feasibility.

• Journal of Biosystems Engineering
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• 제42권2호
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• pp.117-125
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• 2017

Purpose: Damage to pulse crops by wild birds is a serious problem. The damage is to such an extent that the rate of damage during the period between seeding and cotyledon stages reaches 54.6% on an average. In this study, a crop-position detection method was developed wherein infrared (IR) sensors were used to determine the cotyledon position under a vinyl mulch. Methods: IR sensors that helped measure the temperature were used to locate the cotyledons below the vinyl mulch. A single IR sensor module was installed at three locations of the crops (peanut, red lettuce, and crown daisy) in the cotyledon stage. The representative thermal response of a $16{\times}4$ pixel area was detected using this sensor in the case where the distance from the target was 25 cm. A spatial image was applied to the two-dimensional temperature distribution using a non-integral moving-average method. The collected data were first processed by taking the moving average via interpolation to determine the frame where the variance was the lowest for a resolution unit of 1.02 cm. Results: The temperature distribution was plotted corresponding to a distance of 10 cm between the crops. A clear leaf pattern of the crop was visually confirmed. However, the temperature distribution after the normalization was unclear. The image conversion and frequency-conversion graphs were obtained based on the moving average by averaging the points corresponding to a frequency of 40 Hz for 8 pixels. The most optimized resolutions at locations 1, 2, and 3 were found on 3.4, 4.1, and 5.6 Pixels, respectively. Conclusions: In this study, to solve the problem of damage caused by birds to crops in the cotyledon stage after seeding, the vinyl mulch is punched after seeding. The crops in the cotyledon stage could be accurately located using the proposed method. By conducting the experiments using the single IR sensor and a sliding mechanical device with the help of a non-integral interpolation method, the crops in the cotyledon stage could be precisely located.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권6호
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• pp.309-313
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• 2002

In this paper, we have studied minimization of the kerf-width and surface burning, which occurred after the conventional singulation process of the multi-layer BGA board with copper, polyethylene and epoxy glass fiber. The high thermal energy of a pulsed Nd:YAG laser is used to cut the multi-layer board. The most considerable matter in the laser cutting of the multi-layer BGA boards is their different absorption coefficient to the laser beam and their different heat conductivity. The cut mechanism of a multi-layer BGA board using a 2$^{nd}$ harmonic Nd:YAG laser is the thermal vaporization by high temperature rise based on the Gaussian profile and copper melting point. In this experiment, we found that the sacrifice layer and Na blowing are effective in minimizing the surface burning by the reaction between oxygen in the air and the laser beam. In addition, N2 blowing reduces laser energy loss by debris and suppresses surface oxidation. Also, the beam incidence on the epoxy layer compared to polyimide was much more suitable to reduce damage to polyimide with copper wire for the multi layer BGA singulation. When the polyester double-sided tape is used as a sacrifice layer, surface carbonization becomes less. The SEM, non-contact 3D inspector and high-resolution microscope are used to measure cut line-width and surface morphology.

• Journal of Biosystems Engineering
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• 제25권4호
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• pp.293-300
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• 2000

Automated greenhouse production system often require crop growth monitoring involving accurate quantification of plant physiological properties. Conventional methods are usually burdensome, inaccurate, and harmful to crops. A thermal image analysis system can accomplish rapid and accurate measurements of physiological-property changes of stressed crops. In this research a thermal imaging system was used to measure the leaf-temperature changes of several crops according to nutrient stresses. Thermal images were obtained from lettuce, cucumber, and pepper plants. Plants were placed in growth chamber to provide relatively constant growth environment. Results showed that there were significant differences in the temperature of stressed plants and non-stressed plants. In a case of the both N deficiency and excess, the leaf temperatures of cucumber were $2^{\circ}C$ lower than controlled temperature. The leaf temperature of cucumber was $2^{\circ}C$ lower than controlled temperature only when it was under N excess stress. For the potassium deficiency or excess stress, the leaf temperaures of cucumber and hot pepper were $2^{\circ}C$ lower than controls, respectively. The phosphorous deficiency stress dropped the leaf temperatures of cucumber and hot pepper $2^{\circ}C$ and $1.5^{\circ}C$ below than controls. However, the leaf temperature of lettuce did not change. It was possible to detect the changes in leaf temperature by infrared thermography when subjected to nutrition stress. Since the changes in leaf temperatures were different each other for plants and kinds of stresses, however, it is necessary to add a nutrient measurement system to a plant-growth monitoring system using thermography.

• 한국표면공학회지
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• 제34권5호
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• pp.395-402
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• 2001

An induction thermal plasma system have been newly designed for advanced operation with a pulse modulated mode to control the plasma power in time domain and to create non-equilibrium effects such as fast quenching of the plasma to produce new functional materials in high rate. The system consists of MOSFET power supply with a maximum power of 50 kW with a frequency of 460 kHz, an induction plasma torch with a 10-turns coil of 80 mm diameter and 150 mm length and a vacuum chamber. The pulse modulated plasma was successfully generated at a plasma power of 30 kW and a high pressure of 100 kPa, with taking the on and off time as 10 ms, respectively. Measurements were carried out on the time-dependent spectral lines emitted from Ar species. The dynamic behavior of plasma temperature in a pulse cycle was estimated by the Boltzmann plot and the excitation temperature of Ar atom was found to be changed periodically from around 0.5 to 1.7 eV during the cycle. Two application regions of the induction thermal plasma newly generated were introduced to material processing with high rate synthesis based on non equilibrium effects, and to the finding of new arc quenching gases coming necessary for power circuit breaker, which is friendly with earth circumstance alternative to SF6 gas.

• 비파괴검사학회지
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• 제37권2호
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• pp.75-83
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• 2017

In this paper, we investigate the capacity of the lock-in infrared thermography technique for the evaluation of non-uniform top layers of a silicon carbide coating with a nickel based superalloy sample. The method utilized a multilayer heat transfer model to analyze the surface temperature response. The modelling of the sample was done in ANSYS. The sample consists of three layers, namely, the metal substrate, bond coat and top coat. A sinusoidal heating at different excitation frequencies was imposed upon the top layer of the sample according to the experimental procedures. The thermal response of the excited surface was recorded, and the phase angle image was computed by Fourier transform using the image processing software, MATLAB and Thermofit Pro. The correlation between the coating thickness and phase angle was established for each excitation frequency. The most appropriate excitation frequency was found to be 0.05 Hz. The method demonstrated potential in the evaluation of coating thickness and it was successfully applied to measure the non-uniform top layers ranging from 0.05 mm to 1 mm with an accuracy of 0.000002 mm to 0.045 mm.

• 한국축산식품학회지
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• 제37권4호
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• pp.477-485
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• 2017

Novel, effective methods to control and prevent spoilage and contamination by pathogenic microorganisms in meat and meat products are in constant demand. Non-thermal pasteurization is an ideal method for the preservation of meat and meat products because it does not use heat during the pasteurization process. Atmospheric pressure cold plasma (APCP) is a new technology for the non-thermal pasteurization of meat and meat products. Several recent studies have shown that APCP treatment reduces the number of pathogenic microorganisms in meat and meat products. Furthermore, APCP treatment can be used to generate nitrite, which is an essential component of the curing process. Here, we introduce the effectiveness of APCP treatment as a pasteurization method and/or curing process for use in the meat and meat product processing industry.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.421-424
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• 2011

본 연구에서는 열분석법을 이용하여 혼합 액체연료의 수치해석에 필요한 여러 가지 인자를 측정하였다. 이러한 열분석법에는 열중량 분석방법(TGA, Thermo-Gravimetric Analyzer)과 시차 주사열량 측정법(DSC, Differential Scanning Calorimetry)이 있다. 열중량 분석방법을 통한 비등온 실험(non-isothermal experimental) 결과를 토대로 Freeman Carroll의 수학적인 후처리 방법을 이용하여 미지의 액체연료의 구성 성분에 대한 동역학적 변수인 활성화 온도와 반응차수로 각각 6128.2 K와 1.4를 얻었다. 그 외 다양한 수학적 처리 방법에 따른 동역학적 변수의 값을 구해보았고, 계산 결과는 처리방법에 따라 약간의 차이를 보였다.

• 한국포장학회지
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• 제26권1호
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• pp.1-9
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• 2020

We evaluated the applicability of baking soda, charco'al, coffee, and green tea as a natural deodorant in Kimchi packaging. Moreover, to evaluate the potential usage of these deodorants in packaging materials and confirm their applicability in high-temperature melt-extrusion processing, the thermal stabilities of the deodorants were investigated, and heat-treated deodorants were evaluated in terms of the deodorizing function compared with non-treated deodorants. Aroma patterns were decreased after deodorizing treatment with all-natural deodorants. Dimethyl disulfide, methyl trisulfide, and diallyl disulfide, the most significant odorous Volatile organic compounds (VOCs) of Kimchi, decreased after treatment with the deodorants. In particular, baking soda and charcoal showed the highest efficiency in removing odorous compounds and VOCs from Kimchi, even after high-temperature processing. The acetic acid removal rates for both baking soda and charcoal were 99.9±0.0%. The heating process increases the deodorizing effects of baking soda. Sensory evaluation results showed that there is a significant increase (p < 0.05) in the overall preference for Kimchi samples packaged with charcoal and baking soda. This study provides useful information for the deodorization effects of natural deodorants for Kimchi smell and their applicability for packaging materials.

• 한국포장학회지
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• 제21권1호
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• pp.27-34
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• 2015

전자레인지 가열용 제품에서 마이크로파에 의한 불균일한 가열이 일어남에 따라 포장재의 특정 부위에 열 변형이 발생하여 전자레인지 포장 소재에 따른 가열조리 패턴을 조사하였다. 전자레인지 가열용 포장재의 내면으로 이용되는 CPP의 grade에 따른 인장강도, 내열성 및 신장률을 비교하였다. High retortable CPP는 일반 CPP 재질과 비교하여 강한 열 접착강도 및 내열 저항성을 가지고 있었다. 국외 및 국내 CPP 제품의 인장강도 및 신장율은 차이가 있지만 대부분 $160^{\circ}C$ 정도 수준의 내열성을 가지고 있는 것으로 조사되었다. 하지만 소스의 높은 점도와 염분을 함유하는 hot spicy 제품에서는 전자파의 침투가 원활하지 못하여 전자레인지 조리 시 내용물의 균일한 가열이 어려워 국지적 또는 액위선 부위에 포장재의 열 변형이 관찰되었다. G-PET/PET/PET/CPP와 G-PET/PET/NY/CPP로 구성된 포장재를 레토르트 처리했을 때와 레토르트 후 전자레인지 가열 처리하였을 때 상태변화 및 합지강도에 대한 분석결과 합지강도의 차이는 없었으나 레토르트 처리 후 CPP 층의 변형이 관찰되었다. $TiO_2$가 포함된 유백 파우치와 투명 파우치의 열 변형 정도를 비교하였을 때는 $TiO_2$가 포함된 포장재의 열 변형이 더 심하였고, 알루미늄 호일을 부착한 후 전자레인지 가열하였을 때에는 액위선에서 열 변형이 발생되지 않았지만 바닥면에서 열 변형이 관찰되었다. 제품의 내면인 CPP 층의 개질/개선을 통한 내열안정성 확보 및 포장재의 전자파 투과-반사능을 조절하여 포장 내 전자파의 집중을 방지하는 등의 기술 도입 가능성의 검토가 필요할 것으로 판단된다.