• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.187-196
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• 2011

Induction motors play a vital role in aeronautical and automotive industries so that many researchers have studied on developing a fault detection and classification system of an induction motor to minimize economical damage caused by its fault. With this reason, this paper extracts robust feature vectors from the normal/abnormal vibration signals of the induction motor in noise circumstance: partial autocorrelation (PARCOR) coefficient, log spectrum powers (LSP), cepstrum coefficients mean (CCM), and mel-frequency cepstrum coefficient (MFCC). Then, we classified different types of faults of the induction motor by using the extracted feature vectors as inputs of a neural network. To find optimal feature vectors, this paper evaluated classification performance with 2 to 20 different feature vectors. Experimental results showed that five to six features were good enough to give almost 100% classification accuracy except features by CCM. Furthermore, we considered that vibration signals could include noise components caused by surroundings. Thus, we added white Gaussian noise to original vibration signals, and then evaluated classification performance. The evaluation results yielded that LSP was the most robust in noise circumstance, then PARCOR and MFCC followed by LSP, respectively.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.12-21
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• 2004

Error control is one of major concerns in many electronic systems. Experience shows that most malfunctions during system operation are caused by transient faults, which often mean abnormal signal delays that may result in violations of circuit element timing constraints. This paper presents a novel CMOS-based concurrent timing error detector that makes a flip-flop to sense and then signal whether its data has been potentially corrupted or not by a setup or hold timing violation. Designed circuit performs a quiescent supply current evaluation to determine timing violation from the input changes in relation to a clock edge. If the input is too close to the clock time, the resulting switching transient current in the detection circuit exceeds a reference threshold at the instant of the clock transition and an error is flagged. The circuit is designed with a $0.25{\mu}m$ standard CMOS technology at a 2.5 V supply voltage. The validity and effectiveness are verified through the HSPICE simulation. The simulation results in this paper shows that designed circuit can be used to detect setup and hold time violations effectively in clocked circuit element.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.981-986
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• 2004

This study were investigated the effects of physiologically active compounds isolated from Platycodon grandiflorum on streptozotocin-induced diabetic rats. The experimental groups were divided into six groups, normal, diabetic control (CM), and four experimental groups (inulin (IN), inulin + saponin (IS), oligosaccharide (OS), and total extract group (WE)). The rats have free access to water and diet. Experimental groups were administered orally with inulin (630 mg/mL), inulin (630 mg/mL) + saponin (25.2 mg/mL), oligosaccharide (367.5 mg/mL), and total extract (225 mg/mL) into the diabetic rats for 5 weeks after STZ injection; The levels of fasting blood glucose in diabetic control increased by 10.0% for 5 weeks, but the level of blood glucose in inulin and total extract groups decreased by 21.3% and 21.2%, respectively. The concentrations of total cholesterol and triglyceride in serum of diabetic rats fed physiologically activity compounds were lower than those in diabetic control rats. HDL-cholesterol was similar among all the groups. Weights of testicle and heart were lighter, while weight of kidney was significantly increased in diabetic groups than normal group. The concentrations of serum protein insulin and albumin in diabetic groups were significantly decreased compared with those of the normal group. Urinary glucose excretion was decreased in inulin group than other diabetic groups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.528-535
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• 2020

Recently, the protection coordination method of DC systems has been presented because renewable energy and distributed resources are being installed and operated in distribution systems. On the other hand, it is difficult to detect ground faults because there is no significant difference compared to a steady-state current in ungrounded IT systems, such as DC load networks and urban railways. Therefore, this paper formulates the detection principle of IMD (Insulation Monitoring Device) to use it as a protection coordination device in a DC system. Based on the signal injection method of IMD, which is analyzed by a wavelet transform, this paper presents an algorithm of detecting ground faults in a DC system in a fast and accurate manner. In addition, this paper modeled an IMD and an ungrounded DC system using the PSCAD/EMTDC S/W and performed numerical analysis of a wavelet transform with the Matlab S/W. The simulation results of a ground fault case in an ungrounded DC system showed that the proposed algorithm and modeling are useful and practical tools for detecting a ground fault in a DC system.

• The Korean Journal of Food And Nutrition
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• v.19 no.1
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• pp.103-109
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• 2006

This study was designed to investigate the influence of Eosungcho (Houttuynia cordata Thunb) mixture on the plasma lipids of pigs. Experimental groups were divided into 3 groups: control group(0%), 5% and 10% Eosungcho feeding groups. Plasma concentration of total cholesterol, atherosclerotic index, free cholesterol and cholesteryl ester were significantly lower in the Eosungcho powder 5% and 10% feeding groups than control group. Plasma contents of HDL-cholesterol, cholesteryl ester ratio, triglyceride and phospholipid were significantly different between 10% Eosungcho feeding group and control group. Plasma concentration of LDL-cholesterol was significantly love in 10% Eosungcho feeding group($76.5{\pm}5.4mg/dL$) than in control group($86.5{\pm}5.6mg/dL$). Plasma concentration of VLDL and chylomicron were showed similar tendency to LDL-cholesterol. Also, blood sugar, GOT and GPT concentration were significantly lower in 10% Eosungcho feeding group than in control group. In control group, the ratio of saturated fatty acid to unsaturated fatty acid was 58.1 : 51.9, but in 5% and 10% Eosungcho feeding groups, those were 42.1 : 57.9 and 41.0 : 59.0, respectively. The component of main fatty acid was different between control group and Eosungcho feeding groups. In Eosungcho feeding groups, main unsaturated fatty acids were oleic acid(18:1) and linoleic acid(18:2). From the results, addition of Eosungcho powder might be effective in improving the plasma lipid components in pigs.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.40-43
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• 2011

최근, 레이저 초음파 영상화 기법은 구조물의 비접촉식 손상 진단을 위해 널리 연구되고 있다. 초음파 영상화 기법의 가장 큰 장점은 비접촉식으로 구조물의 손상을 진단할 수 있고, 가진 및 측정 지점을 자유로이 이동할 수 있다는 점이다. 따라서 이는 고온이나 동적상태의 구조물에 적용이 가능하며, 시간과 공간상의 충분한 데이터를 획득할 수 있으므로 역문제 (Inverse problem)를 해결할 필요 없이 완전한 초음파의 전파 형상을 얻을 수 있다. 지난 연구들에서는 충분한 가진력 혹은 측정 민감도를 확보하기 위해 가진 레이저와 부착형 센서의 조합이나 부착형 가진 트렌스듀서와 센싱 레이저의 조합으로 초음파 영상을 획득하고자 하였다. 하지만 이들 조합은 가진 혹은 측정 지점이 구조물에 부착되어 있어 완전한 비접촉식 기법을 구현하지 못하였다. 이를 극복하고자 레이저와 EMAT 센서 등의 조합이 시도되어 왔으나, 이 또한 EMAT 센서의 적용 거리에 따른 한계점을 지니고 있다. 본 연구에서는 가진 레이저 (Nd:Yag)의 스캐닝을 통해 다양한 가진 점에서 발생된 초음파가 탄성체 구조물을 통해 전파되고, 이를 센싱 레이저 (Laser Doppler Vibrometer)를 이용하여 측정함으로써 비접촉식 초음파 영상화를 구현하였다. 나아가, 정상파 필터(Standing-wave filter)를 이용하여 구현된 초음파 영상으로부터 손상 영향만 검출해 내는 기법을 개발했다. 개발된 기법은 복합재 시편의 층간박리 (Delamination) 진단을 통해 검증하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1347-1351
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• 2006

Microwave radiometry, as a non-invasive technique which doesn't pierce inside human and can measure the temperature, is to diagnose early the disease or abnormality by measuring the temperature inside human. In this paper, as an antenna for measuring human radiometric signals, we simulated and measured a dipole-type antenna with circular loops. As a measured result has a ultra wideband characteristic of $130%(0.8\sim3.8GHz)\;for\;511\leq-10dB$, it is considered to be suitable to detect the position and size of human tissue having various diseases.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.355-360
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• 2010

Vibrio parahaemolyticus (V. parahaemolyticus), which is commonly found in raw seafood, causes gastroenteritis in humans. Rapid and effective methods have been developed as culture methods require up to 5-7 days. In this study, real-time PCR was compared with the standard culture method for detecting V. parahaemolyticus in seafood and radish sprout samples. Five hundred grams of the samples were artificially contaminated with V. parahaemolyticus then divided into 20 samples. The samples were incubated in alkaline peptone water and then streaked onto thiosulfate-citrate-bile saltssucrose agar. Biochemical tests for suspicious colonies were performed using the API 20NE strip. In parallel, real-time PCR was performed targeting the toxR gene using the enrichment broth. The real-time PCR was sensitive in discriminating V. parahaemolyticus from other foodborne pathogens. The detection limit of the real-time PCR was $10^3\;CFU/mL$ in phosphate-buffered saline. Although the real-time PCR detected more positive samples (76 out of 180, 42%) than the culture method (66 out of 180, 37%), there was no significant statistical difference (p>0.05) between the two methods. In conclusion, real-time PCR assays could be an alternative to the standard culture method for detecting V. parahaemolyticus in seafood and radish sprouts, which has many advantages in terms of detection time, labor, and sensitivity.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.3-7
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• 2012

Purpose : In myocardial perfusion SPECT, the type of orbit (circular vs. body contouring) that affect the image quality is still on the debate. Presently in the nuclear medicine field, the body contouring orbit acquisition is widely used to improve the image quality on the myocardial perfusion SPECT. But in case of body contouring acquisition using the vertical method with dual detect machine, there is a tendency of increasing the radius. In this research, we compared body contouring orbit acquisition with circular orbit acquisition, so we suggest ideal method that reduces the radius for improving image quality. Materials and Methods : Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on equally with counts from patient's body. The study was performed under six different conditions. To compare image quality according to the radius, we increased radius sequentially per step during circular orbit acquisition. On the other hand, sensors that protect a collision and reduce the radius automatically were used to acquire image during body contouring orbit acquisition. So we compared FWHM value of apex. In clinical studies, we analyzed the 40 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center in August 2011. To acknowledge the differences according to the radius, we acquired the results two times using circular orbit acquisition and body contouring orbit acquisition. Results : In phantom study, we analyzed that increase of radius resulted in changes of FWHM value. It was 5.41, 6.24, 6.33, 6.42, 6.93 mm. On the other hand, using the body contouring orbit acquisition, FWHM value was 6.23 mm. In clinical study, difference of average radius between two methods was 2.5 cm (circular orbit acquisition was more close to patients). Conclusion : Through the experiments using Anthropomorphic torso phantom and patients data, we found that FWHM value of circular orbit acquisition was lower than body contouring orbit acquisition. As a result, if the difference of average radius exists approximately 3 cm, circular orbit type acquisition is better than body contouring type acquisition. But clinical investigation is only aimed to average radius, so it needs more investigation in comparison of patient's image.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.102-109
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• 2009

Purpose: Flash 3D (pixon(R) method; 3D OSEM) was developed as a software program to shorten exam time and improve image quality through reconstruction, it is an image processing method that usefully be applied to nuclear medicine tomography. If perfoming brain diamox perfusion scan by reconstructing subtracted images by Flash 3D with shortened image acquisition time, there was a problem that SNR of subtracted image is lower than basal image. To increase SNR of subtracted image, we use LEAP collimators, and we emphasized on sensitivity of vessel dilatation than resolution of brain vessel. In this study, our purpose is to confirm possibility of application of LEAP collimators at brain diamox perfusion tomography, identify proper reconstruction factors by using Flash 3D. Materials and methods: (1) The evaluation of phantom: We used Hoffman 3D Brain Phantom with $^{99m}Tc$. We obtained images by LEAP and LEHR collimators (diamox image) and after 6 hours (the half life of $^{99m}Tc$: 6 hours), we use obtained second image (basal image) by same method. Also, we acquired SNR and ratio of white matters/gray matters of each basal image and subtracted image. (2) The evaluation of patient's image: We quantitatively analyzed patients who were examined by LEAP collimators then was classified as a normal group and who were examined by LEHR collimators then was classified as a normal group from 2008. 05 to 2009. 01. We evaluate the results from phantom by substituting factors. We used one-day protocol and injected $^{99m}Tc$-ECD 925 MBq at both basal image acquisition and diamox image acquisition. Results: (1) The evaluation of phantom: After measuring counts from each detector, at basal image 41~46 kcount, stress image 79~90 kcount, subtraction image 40~47 kcount were detected. LEAP was about 102~113 kcount at basal image, 188~210 kcount at stress image and 94~103 at subtraction image kcount were detected. The SNR of LEHR subtraction image was decreased than LEHR basal image about 37%, the SNR of LEAP subtraction image was decreased than LEAP basal image about 17%. The ratio of gray matter versus white matter is 2.2:1 at LEHR basal image and 1.9:1 at subtraction, and at LEAP basal image was 2.4:1 and subtraction image was 2:1. (2) The evaluation of patient's image: the counts acquired by LEHR collimators are about 40~60 kcounts at basal image, and 80~100 kcount at stress image. It was proper to set FWHM as 7 mm at basal and stress image and 11mm at subtraction image. LEAP was about 80~100 kcount at basal image and 180~200 kcount at stress image. LEAP images could reduce blurring by setting FWHM as 5 mm at basal and stress images and 7 mm at subtraction image. At basal and stress image, LEHR image was superior than LEAP image. But in case of subtraction image like a phantom experiment, it showed rough image because SNR of LEHR image was decreased. On the other hand, in case of subtraction LEAP image was better than LEHR image in SNR and sensitivity. In all LEHR and LEAP collimator images, proper subset and iteration frequency was 8 times. Conclusions: We could archive more clear and high SNR subtraction image by using proper filter with LEAP collimator. In case of applying one day protocol and reconstructing by Flash 3D, we could consider application of LEAP collimator to acquire better subtraction image.