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Sanghun Lee,Sunhwan Jang,Cam Nguyen,Dae-Hyun Choi,Jusung Kim 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.4
In this paper, we integrate a divide-by-3 injection-locked frequency divider (ILFD) in CMOS technology with a 0.18-μm BiCMOS process. We propose a self-injection technique that utilizes harmonic conversion to improve the locking range, phase-noise, and input sensitivity simultaneously. The proposed self-injection technique consists of an oddto-even harmonic converter and a feedback amplifier. This technique offers the advantage of increasing the injection efficiency at even harmonics and thus realizes the low-power implementation of an oddorder division ILFD. The measurement results using the proposed self-injection technique show that the locking range is increased by 47.8% and the phase noise is reduced by 14.7 dBc/Hz at 1-MHz offset frequency with the injection power of -12 dBm. The designed divide-by-3 ILFD occupies 0.048 mm² with a power consumption of 18.2-mW from a 1.8-V power supply.
Sanghun Lee,Ki-Yuol Jung,Hyen-Chung Chun,Young-Dae Choi,Hang-Won Kang 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.2
Subsurface drip irrigation (SDI) system is considered one of the most effective methods for water application. A 2-year field study was conducted to investigate the effect of SDI systems with various dripline spacing (0.7 or 1.4 m) and position (under furrow or ridge) on soybean (Glycine max L.) production at a sandy-loam soil in Miryang, South Korea. For 2016-2017, average grain yield in SDI irrigated plots, 3.16 Mg ㏊<SUP>-1</SUP>, was statistically greater than rainfed irrigated plot (2.63 Mg ㏊<SUP>-1</SUP>). Soybean grain yield averaged 3.25 Mg ㏊<SUP>-1</SUP> for the 0.7 m dripline spacing and 3.07 Mg ㏊<SUP>-1</SUP> for the 1.4 m spacing for the two-year period compared to a rainfed irrigated average of 2.63 Mg ㏊<SUP>-1</SUP> for the same period. Soybean treated with SDI system had significantly greater values of normalized difference vegetation index and stomatal conductance, indicating that soybean plants in SDI plots had greater photosynthetic and stomatal activity due to the higher water availability in soil. Irrigation water use efficiency (IWUE) was greatest in the plot of 0.7 m spacing installed under ridge position than any other plot across growing season. Average soil water content in plots with 0.7 m dripline spacing was 0.21 ㎥ m<SUP>-3</SUP> at 5 ㎝ depth layer, which was 45% greater compared to the plots with 1.4 m spacing, even though the gross irrigation amounts were greater in 1.4 m spacing plots. It is concluded that wide dripline spacing (1.4 m) is probably the more economical installation design for SDI system compared to 0.7 m spacing in this study soil because the initial cost for dripline may be reduced with wide spacing design, even though the IWUE is greater in the plot of 0.7 m dripline spacing.
Development of Deep Learning Color Recognition Model for Color Measurement Processes
Lee Sanghun,Kim Ki-Sub,Kang Jeong Won 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4
We present a deep learning color recognition model for the color measurement process in the paint industry. Currently, spectrophotometers are primarily used for color measurements owing to their accuracy. The measurement method involves manually injecting the sample into a spectrophotometer. Our proposed method uses a webcam with a deep learning model on the stand of a spectrophotometer. Deep learning models are widely used for image and color detection. In this study, the “you only look once (YOLO)” algorithm is applied for real-time detection of color samples. Upon training various sample images using YOLO, the model could detect the sample area in real time using a webcam. An open source computer vision (OpenCV) library was used for the color recognition model, and the detected RGB color value was converted to the international commission on illumination color space (CIELAB) value, which is primarily used in the color measuring process. However, because of the mirror-like refl ection of light from a surface with specular refl ection, it is diffi cult to implement the color value using a camera. To address this problem, we compare several specular removal methods and propose the most suitable model for the color recognition model of color samples. The accuracy of the proposed model was verifi ed by comparing the colors of various samples. Our proposed approach can easily detect samples and color values, which can contribute signifi cantly to automatically calculating the exact amount of coloring required for the target color.
Lee, Sanghun,Jang, Sunhwan,Nguyen, Cam,Choi, Dae-Hyun,Kim, Jusung The Institute of Electronics and Information Engin 2017 Journal of semiconductor technology and science Vol.17 No.4
In this paper, we integrate a divide-by-3 injection-locked frequency divider (ILFD) in CMOS technology with a $0.18-{\mu}m$ BiCMOS process. We propose a self-injection technique that utilizes harmonic conversion to improve the locking range, phase-noise, and input sensitivity simultaneously. The proposed self-injection technique consists of an odd-to-even harmonic converter and a feedback amplifier. This technique offers the advantage of increasing the injection efficiency at even harmonics and thus realizes the low-power implementation of an odd-order division ILFD. The measurement results using the proposed self-injection technique show that the locking range is increased by 47.8% and the phase noise is reduced by 14.7 dBc/Hz at 1-MHz offset frequency with the injection power of -12 dBm. The designed divide-by-3 ILFD occupies $0.048mm^2$ with a power consumption of 18.2-mW from a 1.8-V power supply.
Sanghun Lee,Ki-Yuol Jung,Hyen Chung Chun,Young Dae Choi 한국작물학회 2017 Korean journal of crop science Vol.62 No.2
Crop production in rice paddy fields is of great importance because of declining rice consumption and the low self-sufficiency ratio for field crops in Korea. A controlled drainage system (CDS) is recognized as an effective means to adjust water table (WT) levels as needed and control soil water content to improve the soil environment for optimum crop growth. The present study evaluated the effects of a CDS on soil characteristics, including soil water distribution and soybean development in paddy fields. The CDS was installed with two drain spacing (3 m and 6 m) at the experimental paddy field at the National Institute of Crop Science, Miryang, Korea. It was managed with two WT levels (0.3 m and 0.6 m) during the growing season. Soil water content, electrical conductivity and plant available nitrogen content in the soil were significantly greater in the 0.3 m WT management plots than in the 0.6 m plot and the control. At the vegetative stage, chlorophyll content was significantly lower with higher WT control because of excess soil moisture, but it recovered after the flowering stage. Soybean yield increased with WT management and the 0.6 m WT treatment produced the greatest grain yield, 3.38 ton ha-1, which was 50% greater than that of the control. The CDS directly influenced outflow through the drains, which significantly delayed nutrient loss. The results of this study indicated that WT management by CDS can influence soil characteristics and it is an important practice for high yielding soybean production in paddy fields, which should be considered the crop growth stages for stable crop production.
Effect of Subsurface Drainage Systems on Soil Salinity at Saemangeum Reclaimed Tidal Land
Sanghun Lee,Hui-Su Bae,Soo-Hwan Lee,Yang-Yeol Oh,Jin-Hee Ryu,Jong-Cheol Ko,Ha-Chul Hong,Yong-Doo Kim,Sun-Lim Kim 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.6
Soil salinity is the most critical factor for crop production at reclaimed tidal saline soil. Subsurface drainage system is recognized as a powerful tool for the process of desalinization in saline soil. The objective of this study was to investigate the effects of subsurface drainage systems on soil salinity and corn development at Saemangeum reclaimed tidal saline soil. The field experiments were carried out between 2012 and 2014 at Saemangeum reclaimed tidal land, Buan, Korea. Subsurface drainage was installed with four treatments: 1) drain spacing of 5 m, 2) drain spacing 10 m, 3) double layer with drain spacing 5 m and 10 m, and 4) the control without any treatment. The levels of water table showed shorter periods above 60 cm levels with the deeper installation of subsurface drainage system. Water soluble cations were significantly greater than exchangeable forms and soluble Na contents, especially in surface layer, were greatly reduced with the installation of subsurface drainage system. Subsurface drainage system improved biomass yield of corn and withering rate. Thus, the biomass yield of corn was improved and the shoot growth was more affected by salinity than was the root growth. The efficiency of double layer was not significant compared with the drain spacing of 5 m. The economic return to growers at reclaimed tidal saline soil was the greatest by the subsurface drainage system with 5 m drain spacing. Our results demonstrated that the installation of subsurface drainage system with drain space of 5 m spacing would be a best management practice to control soil salinity and corn development at Saemangeum reclaimed tidal saline soil.