• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.773-787
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• 2006

An airborne radar is an essential aviation electronic system for the aircraft to perform various civil and/or military missions in all weather environments. This paper presents the design, development, and test results of the multi-mode X-band pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRUs(Line-Replacement Unit), which include antenna unit, transmitter and receiver unit, radar signal & data processing unit and display Unit. The developed core technologies include the planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, MTI, DSP based Doppler FFT filter, adaptive CFAR, moving clutter compensation, platform motion stabilizer, and tracking capability. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test as well as helicopter-borne field tests including MTD(Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.429-435
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• 2017

In order to increase the therapeutic effect of radiation, there has been an increase in the use of conventional photon therapy. The intensive care unit should pay more attention to the radiation safety evaluation due to the higher energy and the larger facility compared to the existing Photon treatment. These radiation safety evaluations are mainly performed by using Monte Carlo simulation, and the first thing to be done is geometric modeling. The Heavy-ion treatment facility uses synchrotron as the accelerating device, which is difficult to precisely model geometrically and is mostly modeled briefly. This study investigated the effect of simplification and precise implementation of Dipole magnet among the components of synchrotron acceleration device on the radiation safety evaluation. The results show that the simplified geometric model is overestimated with the precisely implemented geometric model. Therefore, it is considered that the radiological safety evaluation results in more reliable results of the precise geometric modeling.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.199-202
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• 2008

A high performance liquid chromatographic (HPLC) method for the simultaneous determination of hesperidin and glycyrrhizin was established for the quality control of traditional herbal medicinal preparation, Pyungwi-san (PWS). Separation and quantification were successfully achieved with a Waters XTerra RP18 column ($5{\mu}m$, 4.6 mm I.D. ${\times}$ 150 mm) by gradient elution of a mixture of acetonitrile and water containing 0.03% phosphoric acid (pH 2.03) at a flow rate of 1.0 ml/min. The diode-array UV/vis detector (DAD) was used for the detection and the wavelength for quantification was set at 230 nm. The presence of hesperidin and glycyrrhizin in this extract was ascertained by retention time, spiking with each authentic standard and UV spectrum. All four compounds showed good linearity $(r^2>0.995)$ in a relatively wide concentration ranges. The R.S.D. for intra-day and inter-day precision was less than 7.0% and the limits of detection (LOD) were less than 60 ng. The mean recovery of each compound was 99.0-105.6% with R.S.D. values less than 4.0%. This method was successfully applied to the determination of contents of hesperidin and glycyrrhizin in three commercial products of PWS. These results suggest that the developed HPLC method is simple, effective and could be readily utilized as a quality control method for commercial PWS products.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.40-45
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• 1993

일반적으로 건물 구조물에 전달되는 기계진동을 감소시키기 위해서 기계와 기초사이에 유연한 방진소자를 삽입하여 기계가진력(exciting force)의 전달 률을 줄인다. 또한 구조물의 고유진동수와 진동원의 가진주파수가 일치할 경 우, 가진주파수를 변화시키거나, 구조물의 동특성을 변화시키는 방법을 사용 한다. 어떠한 방안을 선택하든 효과적이고 정량적인 방진 시스템을 구성하고 구조물의 정확한 진동상태를 예측하기 위해서는 진동원의 가진특성과 구조 물의 동특성에 대한 정보가 요구된다. 일반적으로 방진설계를 위해 필요한 진동원의 가진특성은 제조회사의 사양이나 측정을 통하여 비교적 쉽게 얻을 수 있다. 복합재료, 다양한 경계조건, 복잡한 대형구조물등은 수치해석을 이 용하여 해석적인 방법으로 동특성을 구할 경우, 신뢰성 있는 정보를 얻기에 는 많은 노력이 요구된다. 더우기 현장에서 발생하는 진동문제는 대부분 복 잡하고 시간적으로 시급히 해결해야 하기 때문에 효율적인 절차를 구성하여 구조물의 동특성을 해석하는 방법을 사용할 필요가 있다. 구조물의 동특성은 실험적인 방법을 통하여 구하고 그 외의 필요한 계산들은 해석을 통하여 얻 는 것이 효율적일 수 있다. 실험적 동특성해석은 입력하중에 대한 응답의 크 기와 위상 비를 주파수별로 나타내는 전달함수를 측정하는 방법으로서 가진 장치 및 여러 측정/분석 장비가 필요하며, 철교, 교량, 건물의 철골 및 콘크 리트 슬라브등 다양한 중대형의 구조물을 Signal/Noise비가 좋도록 가진 시 켜야 할 필요성이 있다. 본 연구에서는 이러한 실험적 방법의 현장 적응성과 신뢰성을 확보하기 위해 대형충격기(large impact hammer, max, peak force 약 10000N, time duration 약 20ms)를 제작하고 실험/분석 시스템 및 구조물 의 진동제어를 위한 절차를 Fig.1과 같이 구성하고 이를 철근콘크리트 건물 에 설치한 기계식 주차설비의 진동제어에 적용하였다.force response simulation)를 수행하여 임의의 좌표 공간에 대한 진동수준을 해석적으로 예측할 뿐만 아니라 구조물의 진동제어 를 위한 동적인자를 변경시킬 수 있는 정보를 제공하며 장비를 방진할 경우 신뢰성 있는 전달률을 결정할 수 있다. 실험적으로 철교, 교량이나 건물의 철골구조 및 2층 바닥 등 대,중형의 복잡한 구조물에 대항 동특성을 나타내 는 모빌리티를 결정할 경우 충격 가진 실험이 사용되는 실험장비 측면에서 나 실험을 수행하는 과정이 대체적으로 간편하다. 그러나 이 경우 대상 구조 물을 충분히 가진시킬수 있는 용량의 대형 충격기(large impact hammer)가 필요하게 된다. 이러한 동적실험은 약 길이 61m, 폭 16m의 4경간 교량에 대 하여 동적실험을 수행하여 가능성을 확인하였다. 여기서는 실험실 수준의 평 판모델을 제작하고 실제 현장에서 이루어질 수 있는 진동제어 구조물에 대 한 동적실험 및 FRS를 수행하는 과정과 동일하게 따름으로써 실제 발생할 수 있는 오차나 error를 실험실내의 차원에서 파악하여 진동원을 있는 구조 물에 대한 진동제어기술을 보유하고자 한다. 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다.ofile whereas relaxivity at high field is not affected by τS. On the other hand, the change in τV does not affect low field profile but strongly in fluences on both inflection fie이 and the maximum relaxivity value. The results shows a fluences on both inflection field and the maximum relaxivity value. The results shows

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.57-64
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• 2002

This study was carried out to investigate the effect of yucca extract on the flavor development in Chungkookjang fermented by Bacrillus sp. b01. The changes in the contents of amino-type N, ammonia type N, volatile compounds and organic acids, and those in the activities of ${\alpha}-amylase$ and protease were also determined with aging period. The amount of amino-type N increased gradually with time and was slightly higher in Chungkookjang containing yucca extract than in control. The content of ammonia-type N in Chungkookjang decreased by the addition of yucca extract. During aging, a little higher amylase activity was detected in Chungkookjang containing yucca extract. However, the amylase activity was the lowest in Chungkookjang containing 1 mg/g of yucca extract. The protease activity was slightly higher in Chungkookjang containing yucca extract. The organic acids, such as citrate, acetate, malate, fumarate, and succinate, were detected. The yucca extract reduced the production of tetramethylpyrazine which was responsible for the unpleasant odor, but enhanced the production of 2,5-dimethylpyrazine and 2,6-dimethylpyrazine which contributed to the taste. Sensory evaluation showed that the addition of yucca extract of 0.5 mg/g significantly improved the flavor and taste of products.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.353-359
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• 2020

In this study, the controller structure and control algorithm of medical robot bed developed for pressure ulcer prevention and healing are described. The existing pressure ulcer prevention mattress is operated manually and the remaining maximum body pressure exceeds the pressure of ulcer generation, so there is always room for pressure ulcers. However, the system developed in this study does not generate the pressure ulcers because the body pressure drops to zero when the keyboard of the bed descends using the active electric driving keyboard. In addition, even if the bed is raised and the pressure above the critical body ulcer pressure is abnormal, the device and the control algorithm are designed so that the lasting time is within the pressure ulcer generation critical time and the pressure ulcer itself is not generated. The bed key board motor is a motor designed with the BLDC servos suitable for medical use and these can communicate each other easily through CAN(Car Area Network). The system is new medical robot bed that is effective in preventing pressure ulcers and will be distributed to many patients suffering from pressure ulcers.

• Industry Promotion Research
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• v.2 no.1
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• pp.45-50
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• 2017

This study analyzed the effect of on - the - job training of workers in Chungnam western area on productivity improvement. A total of 76 questionnaires were analyzed for workers in the western part of Chungcheongnam-do that completed the training course of the Korea Polytechnic University Education and Labor Ministry. The results of this study are as follows: First, the higher the motivation to receive the on - the - job training for the improvement of the productivity, the higher the satisfaction of the training of the worker, but the effect on the job productivity was not significant. Second, the correlation between training experience and job productivity was not statistically significant. Third, as for the effect on the productivity improvement according to the rank, the temporary workers showed higher education satisfaction than the regular workers (agency), and the job productivity was higher than the manager (manager level). Results of ANOVA analysis showed that there was a significant effect on educational satisfaction and job satisfaction according to years of work, career, and rank. The purpose of this study is to analyze the effects of on - the - job training of workers in the western part of Chungnam, on the productivity improvement, The validity of the study is significant.

• Spatial Information Research
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• v.22 no.1
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• pp.75-84
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• 2014

Power lines are one of the main obstacles causing an aircraft crash and thus their realtime detection is significantly important during flight. To avoid such flight obstacles, the use of LIDAR has been recently increasing thanks to its advantages that it is less sensitive to weather conditions and can operate in day and night. In this study, we suggest a fast method to detect power lines from LIDAR data for flight obstacle avoidance. The proposed method first extracts non-ground points by eliminating the points reflected from ground surfaces using a filtering process. Second, we calculate the eigenvalues for the covariance matrix from the coordinates of the generated non-ground points and obtain the ratio of eigenvalues. Based on the ratio of eigenvalues, we can classify the points on a linear structure. Finally, among them, we select the points forming horizontally long straight as power-line points. To verify the algorithm, we used both real and simulated data as the input data. From the experimental results, it is shown that the average detection rate and time are 80% and 0.2 second, respectively. If we would improve the method based on the experiment results from the various flight scenario, it will be effectively utilized for a flight obstacle avoidance system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.447-454
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• 2013

A model-based method is proposed to diagnose the gear crack in the gearbox under variable loading condition with the objective to apply it to the wind turbine CMS(Condition Monitoring System). A simple test bed is installed to illustrate the approach, which consists of motors and a pair of spur gears. A crack is imbedded at the tooth root of a gear. Tachometer-based order analysis, being independent on the shaft speed, is employed as a signal processing technique to identify the crack through the impulsive change and the kurtosis. Lumped parameter dynamic model is used to simulate the operation of the test bed. In the model, the parameter related with the crack is inversely estimated by minimizing the difference between the simulated and measured features. In order to illustrate the validation of the method, a simulated signal with a specified parameter is virtually generated from the model, assuming it as the measured signal. Then the parameter is inversely estimated based on the proposed method. The result agrees with the previously specified parameter value, which verifies that the algorithm works successfully. Application to the real crack in the test bed will be addressed in the next study.

• Journal of dental hygiene science
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• v.13 no.1
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• pp.45-52
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• 2013

Antimicrobial activity of extract from some traditional oriental medicinal plants were evaluated for their antimicrobial activity against six oral pathogens, Streptococcus salivarius, Streptococcus oralis, Streptococcus mutans, Streptococcus sanguinis, Lactobacillus acidophilus and Lactobacillus casei, which are associated with caries disease. The antimicrobial activity was examined by determining the inhibition zone using the disc diffusion assay. In antibacterial activity test, extracts of Scutellaria baicalensis, Chrysanthemum indicum, Kochia scoparia, Hydnocarpus anthelmintica and Caesalpinia sappan showed inhibitory effects (40 mg/ml) against tested caries bacteria. Especially, the C. sappan extract showed the strongest activity on S. oralis (40 mm), L. casei (35 mm) and S. mutans (28 mm). Thus, this result suggests that C. sappan may be applicable to preventing dental caries.