• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.142-144
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• 2000

This paper presents an auxiliary TCSC controller designed for damping SSR. Damping controller for SSR is designed in frequency domain for suppressing resonance. The SSR phenomenon and the performance of damping controller simulated by using PSCAD/EMTDC. In this simulation. the power system model for SSR is IEEE benchmark Model and TCSC is simplified to controllable impedance model.

• 한국경영과학회지
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• 제27권4호
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• pp.111-126
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• 2002

This paper presents an interactive decision procedure to aggregate each group member's preferences when each group member articulates his or her preference information incompletely. An index, an indicative for the preference strength between alternatives, is derived to aid each decision maker to articulate preference information about alternatives. We develop a mathematical programming model that can establish dominance relations when the preference information about values of alternatives, attribute weights, and group member's importance weights are provided incompletely. Also, the preference relation between alternatives is to be considered in the model. Based on the preference strength measure and mathematical model, we develop an interactive group decision support procedure.

• Macromolecular Research
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• 제17권11호
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• pp.829-841
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• 2009

This study introduces a specified group-contribution method for predicting the phase equilibria in polymer solutions. The method is based on a modified double lattice model developed previously. The proposed model includes a combinatorial energy contribution that is responsible for the revised Flory-Huggins entropy of mixing, the van der Waals energy contribution from dispersion, a polar force and specific energy contribution. Using the group-interaction parameters obtained from data reduction, the solvent activities for a large variety of mixtures of polymers and solvents over a wide range of temperatures can be predicted with good accuracy. This method is simple but provides improved predictions compared to those of the other group contribution methods.

• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.111-115
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• 2024

This study builds a machine learning model optimized for clocks among various techniques in the field of artificial intelligence and applies it to clock stabilization or synchronization technology based on atomic clock noise characteristics. In addition, the possibility of providing stable source clock data is confirmed through the characteristics of machine learning predicted values during holdover of atomic clocks. The proposed machine learning model is evaluated by comparing its performance with the AutoRegressive Integrated Moving Average (ARIMA) model, an existing statistical clock prediction model. From the results of the analysis, the prediction model proposed in this study (MSE: 9.47476) has a lower MSE value than the ARIMA model (MSE: 221.2622), which means that it provides more accurate predictions. The prediction accuracy is based on understanding the complex nature of data that changes over time and how well the model reflects this. The application of a machine learning prediction model can be seen as a way to overcome the limitations of the statistical-based ARIMA model in time series prediction and achieve improved prediction performance.

• Journal of Information Processing Systems
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• 제19권1호
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• pp.67-79
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• 2023

In the image field, data augmentation refers to increasing the amount of data through an editing method such as rotating or cropping a photo. In this study, a generative adversarial network (GAN) image was created using CycleGAN, and various colors of dogs were reflected through data augmentation. In particular, dog data from the Stanford Dogs Dataset and Oxford-IIIT Pet Dataset were used, and 10 breeds of dog, corresponding to 300 images each, were selected. Subsequently, a GAN image was generated using CycleGAN, and four learning groups were established: 2,000 original photos (group I); 2,000 original photos + 1,000 GAN images (group II); 3,000 original photos (group III); and 3,000 original photos + 1,000 GAN images (group IV). The amount of data in each learning group was augmented using existing data augmentation methods such as rotating, cropping, erasing, and distorting. The augmented photo data were used to train the MobileNet_v3_Large, ResNet-152, InceptionResNet_v2, and NASNet_Large frameworks to evaluate the classification accuracy and loss. The top-3 accuracy for each deep neural network model was as follows: MobileNet_v3_Large of 86.4% (group I), 85.4% (group II), 90.4% (group III), and 89.2% (group IV); ResNet-152 of 82.4% (group I), 83.7% (group II), 84.7% (group III), and 84.9% (group IV); InceptionResNet_v2 of 90.7% (group I), 88.4% (group II), 93.3% (group III), and 93.1% (group IV); and NASNet_Large of 85% (group I), 88.1% (group II), 91.8% (group III), and 92% (group IV). The InceptionResNet_v2 model exhibited the highest image classification accuracy, and the NASNet_Large model exhibited the highest increase in the accuracy owing to data augmentation.

• 구강회복응용과학지
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• 제36권1호
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• pp.29-40
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• 2020

목적: Encoded healing abutment와 scan body를 이용한 디지털 인상과 pick-up 인상용 코핑을 이용한 인상 채득법의 정확도를 다른 임플란트 식립 각도에서 비교 연구하고자 하였다. 연구 재료 및 방법: 3D 프린터를 이용해 주모형을 제작하고 0°, 10° 및 20°의 근심경사로 3개의 임플란트를 위치 시켰다. 각각의 임플란트에 지대주를 체결하고 주모형을 스캔하여 참조 모델을 만들었다. P군 모델은 pick-up 인상용 코핑을 사용하여 15개의 석고 모형을 만들고 지대주를 장착 후 스캔하여 제작하였다. E군과 S군의 모델은 각각 encoded healing abutment와 scan body를 주모형에 체결하고 구내 스캐너를 이용해 15회씩 인상채득을 하여 제작하였다. 각각의 실험군 STL 파일은 best fit alignment를 이용해 참조 모델과 중첩하였고 root mean square (RMS) 값을 분석하였다. 결과: RMS 값은 P군에서 가장 작았고(25.56 ± 2.53 ㎛), 그다음 S군(35.27 ± 2.56 ㎛), E군(38.29 ± 4.12 ㎛) 순 이었다. S군과 E군 사이에는 유의차가 없었고, P군은 S군과 E군 보다 작았다(P < 0.05). 임플란트 각도와 RMS 값의 상관관계는 E군에서 유의하였다(P < 0.05). 결론:Pick-up 인상용 코핑 방법은 encoded healing abutment와 scan body 인상 채득 방법에 비해 더 높은 정확도를 보였고 encoded healing abutment와 scan body 인상 방법은 정확도에서 유의한 차이가 없었다. Encoded healing abutment의 임상적 사용은 가능하나 경사진 임플란트의 인상의 경우 주의하여 사용해야 할 것으로 사료된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.310-312
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• 1994

A partial shunt regulator (PSR) which is the power regulator of KOREASAT is modeled. The modeling of the PSR consist of solar array, power circuit, controller. and load models. To realize simple structure. a voltage source of the PSR controller is used the output voltage of the PSR. The model of the PSR has very complex structure with two additional coupled feedback loops. The complex model is simplified to a simple meaningful model with only main feedback control loop. The proposed model is compared to a PSR model with DC voltage source at the PSR controller. The proposed PSR model is verified by comparing the model with SPICE simulation for small signal analysis.

• 사상체질의학회지
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• 제28권2호
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• pp.147-162
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• 2016

Objectives The objective of this study is to develop a taeeumin animal-experimental model induced lung fibrosis with Bleomycin and evaluate the effect on obesity in this animal-experimental model.Methods The subjects were divided into 3 groups : normal group, high fat diet(HFD) control group, and HFD group administered with bleomycin(n=10 per group). To develop taeeumin animal-experimental model with reduced respiratory metabolism, 8-week-old C57BL/6 mice were administered with 0.03ml solution of bleomycin 1U/ml dissolved in distilled water, intratracheal(IT), once. Then, the HFD control group and the experimental group were fed with high fat diet for 6 weeks. Airway hyperresponsiveness(AHR) to methacholine was measured at the 1st and 3rd week after bleomycin was administered. Food intake and body weight were measured at regular time weekly. After the final experiment, blood was gathered by cardiac puncture for bloodchemical examination and organs(liver, fatty tissue) were remoed, weighted, and mRNA was analyzed.Results and Conclusions Through the experiment, it was found that Bleomycin induced Taeeumin animal-experimental models have leptin resistace. In the experimental group administered with Bleomycin, fatty acid synthesizing gene expression increased and energy metabolizing gene expression decreased. As mRNA expression of adiponectin decreased, it was found that Taeeuim animal-experimental model is susceptible to metabolic syndrome and cardiovascular diseases.

• Journal of Chest Surgery
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• 제28권11호
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• pp.963-966
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• 1995

Ischemia reperfusion injury occurs in various diseases. The role of oxygen free radicals in IR injury of the lung has been spotlighted and many studies have been performed. In this study, we tried to prepare a stable rat lung model for IR injury, focusing on surrounding conditions as hilar stripped left lung, clamped left pulmonary artery and bronchus,and declamped after determined period was passed, and right main pulmonary aretery was clamped. Arterial blood gas analyes were performed at 1, 10, 20, 30, minutes after reperfusion. Before clamping, PaO2 was 95 to 120 mmHg in all animals. There were six groups; Group I : temperature 15o C, and 120 minutes clamping, Group II: 20 oC, and 120 minutes clamping, Group III : 25 oC, and 120 minutes clamping, Group IV : 15oC, 90 minutes clamping, Group V : 20 oC, 90 minutes clamping,Group VI: 20 oC, 75 minutes clamping. Each groups contained 10 Sprague Dayley rats. The humidity was maintained 100 % as circulation imerged isotonic Hartmann`s solution of the pleural cavity. In group IV, V, and VI, PaO2 decreased significantly in all animals immediately after reperfusion, but 43 % survived till 10 minutes after reperfusion, it was 74.0$\pm$5.7, 73.3$\pm$10.8,and 88.2$\pm$17.7 mmHg. Pulmonary edema was observed histologically in 2/10 animals in group IV, 6/10 in group V , 3/10 in group VI, 9/10 in group I, and the other lungs showed all edema. We established a stable model by setting ischemic time,and temperature, between 75 to 90 minutes,15 to 20o C, and isotemperature Hartmann`s solution immersion of the pleural cavity.

• 대한한의학회지
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• 제39권2호
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• pp.1-12
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• 2018

Objectives: The objective of this study is to develop a new animal model with Kidney-hypofunction for Sasang Constitutional Medicine, especially for partial Soyangin(one of four constitution which has good digestive function and poor renal function) by Unilateral Ureteral Obstruction, and to estimate the factor related to obesity, dyslipidemia, and metabolic syndrome. Methods: The C57BL/6J mice were divided into 3 groups : normal group, high fat diet(HFD) control group, and HFD group with Unilateral Ureteral Obstruction(UUO). Then, the HFD control group and the experimental group were fed with high fat diet for 6 weeks. Food intake and body weight were measured at regular time by week. After the final experiment, blood was gathered for bloodchemical examination and organs(liver, fatty tissue) were remoed, weighted, and mRNA was analyzed with real-time PCR. Results: The weight growth rate with High fat diet went down by 8.35% in experimental group and had similar FER with the normal group, while HFD control group had higher weight growth rate and FER than any other groups. Also The experimental group had lower triglyceride and LDL cholesterol rate and higher glucose rate in serum. and in mRNA expression, GLUT-9, the protein related to excretion of uric acid and metabolic syndrome, expressed lower rate than that of HFD control group. and IL-6, a kind of cytokine related to obesity and metabolic syndrome, expressed more than HFD control group. Conclusions: It was found that Kidney-hypofunction animal-experimental model is susceptible to metabolic syndrome.