• Journal of Biosystems Engineering
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• v.39 no.2
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• pp.87-95
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• 2014

Purpose: The purpose of this study was to design a variable frequency LED light system for plant factory which combined red, blue, green, white, and UV lights and controlled the ratio of the light wavelength. In addition, this study evaluated the performance of each combination of LED to verify the applicability. Methods: Four combinations of LED (i.e. Red+Blue, Red+Blue+Green, Red+Blue+White, Red+Blue+UV) were designed using five types of LED. The system was designed to control the duty ratio of each wavelength of LED by 1% interval from 0~100%, the pulse by 1Hz interval from 1~20kHz. Response characteristics of the control system, spectral distribution of each combination, light uniformity and uniformity ratio were measured to test the performance of the system. Results: Clean waveforms were measured from 10Hz to 10kHz regardless of duty ratio. Frequency distortion was observed within 5% of inflection point at frequencies above 10kHz regardless of duty ratio, but it was judged negligible. Spectra showed a normal distribution, and maximum PPF with duty ratio of 100% was $271.4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for the Red+Blue combination. PPF of the Red+Blue+Green combination was $258.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and that of the Red+Blue+White combination was $273.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. PPF of the Red+Blue+UV combination was $267.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Uniformity ratio for the area excepting border showed 0.90 for the Red+Blue and Red+Blue+White combinations, 0.87 for the Red+Blue+Green combination, and 0.88 for the Red+Blue+UV combination. The light was irradiated evenly at the area excepting border, so it was suitable for plant growing. Conclusions: From the results of this study, response characteristics of the control system, spectral distribution of each combination, light uniformity and uniformity ratio were suitable for applying into the plant factory.

• The Korean Journal of Food And Nutrition
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• v.28 no.6
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• pp.1071-1081
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• 2015

Environment-friendly agricultural products are consumed widely, but little is known about consumers' acceptability. The objectives of this study were to 1) determine consumers' acceptability of cucumber when consumed raw, 2) determine differences in appearance liking between environment-friendly and conventionally grown cucumber samples, and 3) analyze the physicochemical properties of cucumber. White dadagi, gasi, non-pesticide mini cucumber, organic gasi, and organic Joseon cucumber samples were evaluated for consumers' acceptability using a nine-point hedonic scale; White dadagi, organic Joseon, and organic gasi cucumber samples showed the highest acceptability scores. However, there were three consumer segmentations differing their degree of cucumber liking and preference. Consumers liked the appearance of organic gasi best. Consumers' preference of cucumbers did not change upon evaluation of the acceptability of the appearance of whole fruit with and without a label indicating an environment-friendly status. Additionally, the physicochemical properties of the cucumbers-including color (skin and flesh), length, circumference, weight, water activity, brix, and texture (hardness and fracturability)-were measured. All measurements showed significant differences among samples, with the exception of water activity and hardness. White dadagi was 3.8 brix, which was the highest among cucumbers, followed by non-pesticide mini cucumber and organic Joseon. White dadagi, organic Joseon, and organic gasi showed greater fracturability than the other cucumber samples.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.44-54
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• 2002

The fresh eggs of African ostrich in Korea were used in this study to investigate their interior and exterior quality characteristics. In ostrich egg shape characteristics, long and short length were measured as 15.1~16.1 cm and 12.1~13.6 cm, respectively. The egg shape index was calculated as 81.0 and the egg shell showed a more g loss white in color than that of hen egg. Calculated breaking strength of egg shell and egg shell surface based on the equation were $41.155kg/cm^3$ and $804.7cm^2$, respectively. Average egg shell thickness including egg shell membrane was 1.89 mm and there are no differences among parts of the shell. The egg shell membrane thickness was 0.10 mm showing relatively thick in equator compared with that of blunt end. The ave rage number of egg shell pores was counted as $19.7/cm^2$ showing relatively high number of egg shell pores at point end and the total number of egg shell pores in an egg was estimated as 15,241. The relative port ion of each parts based on egg weight was estimated as 25.1% for egg yolk, 58.2% for egg white, 16.7% for egg shell and the ratio of egg yolk to egg white (Y/W) was 0.43. The average diameter and the ave rage height of ostrich egg white were 19.7 cm and 13.2 mm, respectively. Calculated the H.U (Haugh Unit) was -69.7 and the pH was 8.3. In ostrich egg yolk, the diameter, the height, the egg yolk index, and it's pH were calculated as 14.4 cm, 29.4 mm, 0.20, and 6.6, respectively. And the egg yolk color showed a more thin in yellow chroma compared with that of hen egg as due to it's thicker membrane.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.8 no.3
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• pp.105-112
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• 1983

This paper discribes technique of the recursive restoration for the images degraded by linear space invariant blur and additive white Gaussian noise. The image is characterized statistically by tis mean and correlation function. An exponential autocorrelation function has been used to model neighborhood model. The vector model was used because of analytical simplicitly and capability to implement brightness correlation function. Base on the vector model, a two-dimensional discrete stochastic a 12 point neighborhood model for represeting images was developme and used the technique of moving window processing to restore blurred and noisy images without dimensionality increesing, It has been shown a 12 point neighborhood model was found to be more adequate than a 8 point pixel model to obtain optimum pixel estimated. If the image is highly correlated, it is necessary to use a large number of points in the neighborhood in order to have improvements in restoring image. It is believed that these result could be applied to a wide range of image processing problem. Because image processing thchniques normally required a 2-D linear filtering.

• Journal of Adhesion and Interface
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• v.15 no.4
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• pp.145-150
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• 2014

Dicyclopentadiene (DCPD)-based hydrocarbon resins are widely used as tackifiers in many applications. In particular, hydrogenated DCPD-based hydrocarbon resins are widely used in premium hot-melt-type adhesives such as hot melt adhesives (HMAs) and/or hot melt pressure-sensitive adhesives (HMPSAs), because are water-white in color and possess excellent stability to light and heat. This article discusses the adhesive performance of various hydrogenated DCPD resins when they are used as tackifiers in styrene-block-copolymer (SBC)-based HMPSAs. This article shows the correlation between the characteristics of tackifiers and the adhesive performance of SBC-based HMPSAs. The higher the softening point of the tackifier, the higher is the $T_g$, softening point, and crossover temperature of the PSAs. High aromatic H wt% content reduces the high-temperature resistance of PSAs, as suggested by the decrease in the crossover temperature and softening point of the PSAs.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.329-334
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• 2010

Purpose: Adhesion after flexor tendon injury is a result of fibrosis between tendon and tendon sheath. This, finally interfere with gliding mechanism of tendon and results in functional problem of hands. Therefore, there have been many trials to reduce adhesion around the tendon. However, there is no standard procedure clinically practiced in hospitals. Mitomycin-C is an antineoplastic alkylating agent that decrease fibroblast proliferation and scar formation. It is commonly used in many surgery to reduce postoperative adhesion. This study was designed to observe the effect of Mitomycin-C on preventing adhesion in injured flexor tendon. Methods: The deep flexor tendon of digit 2 and 4 in the left forepaw of 15 New Zealand White rabbits were subjected to partial tenotomy. In study group, injury site was exposed to a single 5-minute application of Mitomycin-C, and in control group was left untreated. Digit 2 and 4 in the right forepaw of each rabbit were considered as nonadhesion control group. After 2 weeks, the animals were sacrificed and digits were amputated for biomechanical test and histological study. Results: In biomechanical study to measure yield point, mean yield point of non-adhesion control was $17.43{\pm}2.33$ and $25.07{\pm}4.03$ for adhesion control, which proves increase of adhesion in adhesion control group (p<0.05) in 95% confidence. In Mitomycin-C group, mean yield point was $12.71{\pm}4.97$. Compared with adhesion control, there was decrease in adhesiveness in Mitomycin-C group (p<0.05) in 95% confidence. In histological study, the result of adhesion control revealed massive adhesions of bony structure, fibrotic tissue and tendon structure with ablation of the border. However in Mitomycin-C group, we could find increased fibrotic tissue, but adhesion is much lesser than adhesion group and borders between structures remain intact. Conclusion: This study suggests that Mitomycin-C can significantly reduce adhesion of injured flexor tendon in rabbit model.

• Journal of Minimally Invasive Surgery
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• v.21 no.4
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• pp.154-159
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• 2018

Purpose: Intussusception is a common cause of intestinal obstruction in children. While most patients can be treated by enema reduction, about 20% require surgery. We investigated the usefulness and feasibility of laparoscopic surgery and the intraoperative risk of bowel resection. Methods: We retrospectively reviewed pediatric patients who underwent surgery for intussusception from 2010 to 2017. We collected data for age, gender, body weight, associated symptoms, duration of symptoms, white blood cell count, operating time, and postoperative complications. Results: Of 155 patients, 37 (23.8%) underwent surgery due to enema reduction failure in 29 (78.3%), recurrence in 6 (16.3%), a suspicious lead point in 1, and suspicious ischemic change observed on ultrasonography in 1. The mean age was $26.8{\pm}18.9$ months (range, 3.5~76.7 months), and the mean body weight was $12.9{\pm}3.9kg$ (range, 5.4~22.2 kg). Laparoscopic surgery was successful in 29 patients (78.4%), and 7 (18.9%) needed bowel resection and anastomosis. The mean operating time was $56.7{\pm}32.8min$. A lead point was found in 3 patients in the bowel resection group (p=0.005); in addition, the operating time and hospital stay were longer in this group. There were no intra- or postoperative complications. Conclusion: Laparoscopic surgery was successful in 78.4% of the patients with a short hospital stay and early oral intake. The only predictive factor for bowel resection was the presence of a lead point. Laparoscopic surgery may be an optimal treatment intervention for children with intussusception, except for those who show initial peritonitis.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.561-564
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• 2004

This paper proposes a new application of Kalman filter to estimate speed sensorless DC motor. Kalman filter can estimate the system state variables accurately; even the system input is disturbed with noise. In the design, the mathematical model of DC motor in discrete state-space form will be created; the speed of DC motor which is considered as state variable and can be estimated by using Kalman filter. In the experiment; TMS320C31 floating point digital signal processor is used for hardware implementation, the input is disturbed with/and without white noise in the experiment. The experimental results show the speed of DC motor which is estimated by Kalman filter has good accuracy when compared with the results from tacho-meter.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.574-578
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• 2004

In this paper, a nonlinear feedback system is analyzed for a surface micromachined resonant accelerometer. For this, a brief illustration of the plant dynamics is given. In the analysis, the periodic signal in the nonlinear feedback loop is obtained by the limit cycle point, which is best approximated via the describing function method. Considering the characteristic feature of plant dynamics, a simple phase shifted relay with finite slope is designed for the nonlinearity implementation. With a describing function for random plus sinusoidal input, we analyzed the effect of a white Gaussian noise on oscillation frequency. Finally, simulation and experimental result is given.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.411-414
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• 2000

우리가 일반적으로 모니터에서 작업을 하는 경우 주로 백열등이나 형광등의 조명을 켠 상태에서 하게된다 이런 경우 모니터 상의 동일한 색도는 주위 조명이 바뀜에 따라 다르게 느껴지며 특히 주위 조명의 색도와 모니터의 색도가 틀린 경우는 더욱더 다르게 느껴진다[1]～[3]. 이 논문에서는 우리가 생활하는 일반 환경인 백열등이나 형광등 아래의 모니터 상에 영상을 재현 시 주위 조명의 영향을 고려한 색 재현 알고리즘을 제안한다. 임의의 환경에서 사람의 색 인식에 영향을 미치는 요소는 장면에 존재하는 조명의 색 특성과 물체의 색 특성에 의존한다. 단순한 물체의 표면 반사가 아닌 모니터 등의 조명 역할을 하는 표면이 존재하는 경우는 두 개 이상의 조명이 있는 형태이다. 두개 이상의 조명이 존재하는 경우, 사람들이 느끼는 백색점(white point)은 각 조명의 색도 벡터(chromaticity vector)의 조합으로 표현된다. 본 논문에서는 임의 환경에서 사람이 인식하는 백색점을 모델링하기 위하여 주위 환경이 백색점의 인식에 미치는 영향을 분석하였으며 모니터 상의 색 재현시 주위 조명의 영향을 주위 조명에 의해 생성되는 모니터 표면의 경면 반사(specular reflection)에 의한 영향과 인간 시각의 색 순응(color adaptation) 백색점의 변화 두 가지로 나누어 분석하였다.