• Journal of IKEEE
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• v.24 no.3
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• pp.828-837
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• 2020

This paper presents the optimal design of planar flyback transformer suitable for small-size and low-profile of AC to DC adapter for 10W tablet. This paper also proposes the injection winding transformer of Hybrid and Drum types capable of the winding method of automatic type and the reduction of transformer size and leakage inductance(L_k) compared to the conventional mass-production flyback transformer with the winding method of manual type. In particular, the injection winding transformer of Drum type proposed in this paper is constructed in a horizontal laying of its transformer to solve the connection problem of copper plate injection winding on the secondary side of the one of Hybrid type. The primary and secondary windings of the injection winding transformer of Hybrid and Drum types used the conventional winding and the copper plate injection winding, respectively. For the injection winding transformer of Hybrid and Drum types proposed in this paper, the optimal design of planar flyback transformer suitable for small-size and low-profile was carried out using Maxwell 2D and 3D tool.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.26-32
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power Therefore, there has been and still is a growing concern(safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline, especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion limitation of safety voltage and analysis of induction voltage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.510-511
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• 2017

In this paper, we have studied to minimize the lifetime and fault occurrence of LED fixtures, which have a short lifetime and frequent faults. In the current LED chip, the lifetime is semi-permanent, but compared to the lifetime of the LED chip, Drivers do not last long. In recent years, low-priced LED illuminators such as those from China have entered the market, and many consumers are perceiving LED illuminators. In order to solve these problems, we designed an LED illuminator of 25W class by using AC Direct IC, which has a longer lifetime than the conventional driver, by removing the electrolytic capacitor in the LED driving driver which is the cause of the failure.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.127-134
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• 2008

Purpose: The purpose of this study was to determine the expected values of accommodation and vergence system for analysis of binocular vision. Methods: Seventy three healty subjects without past history of eye disease were selected for this study, Patients showing clinical binocular anomalies including manifest squint and intermittent heterotropia were excluded and data was collected on 54 patients(mean age, 25.3${\pm}$2.7 year). Near point of convergence, distance and near phoiras were measured based on objective deviation angle. And then AC/ A ratio, relative accommodation were measured and all of the data were compared with the Morgan's expected values. Results: The values of distance and near heterophoria were 1.24${\pm}$2.72${\Delta}$ and 2.70${\pm}$4.91${\Delta}$ respectively and the gradient AC/A ratio was 3.92${\pm}$2.17${\Delta}$/D which were all about the same compared with the Morgan's expected values. The values of distance negative fusional convergence was same, however, distance positive fusional convergence was 7${\Delta}$ greater than the Morgan's one. There were no significant differences in the range values of both near vergences while the range of distance vergence was relatively larger than the Morgan's one. Positive relative accommodation was +0.37D greater and negative relative accommodation was -0.63D greater than the Morgan's values. Conclusions: The findings in this study appear that the Morgan's expected values have a possibilities of including considerable proximal convergence value. In comparison with Morgan's values, Korean's normal expected values have much different values of especially BO limit, so if the Morgan's values are directly applied to binocular vision analysis for Korean people, it may lead to an inaccurate binocular vision diagnosis. This results can be used to diagnose the accommodation and vergence system of Korean normal young adults.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.6
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• pp.87-94
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• 2003

This paper presents results of the development of the turbo generator system with structure which is HSG(High Speed Generator) installed directly to gas-turbine engine. Turbo generator with a high speed motor-generator directly has many advantages aspects of weight, size, lubrication system and complexity of the system compared of conventional turbo generator system with a gear box. But because of direct high speed operation of the high speed generator, we have to need stable high speed motor driving algorithm for perfect engine ignition when engine start. Also we have to need the design of the Power conditioning unit(PCU) for converting high speed AC output power to conventional AC power or needed DC power.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.124-131
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• 2014

In this paper, we propose the non-contact gesture recognition algorithm using 4- channel electrometer sensor array. ELF(Extremely Low Frequency) EMI and PLN are minimized because ambient electromagnetic noise around sensors has a significant impact on entire data in indoor environments. In this study, we transform AC-type data into DC-type data by applying a 10Hz LPF as well as a maximum buffer value extracting algorithm considering H/W sampling rate. In addition, we minimize the noise with the Kalman filter and extract 2-dimensional movement information by taking difference value between two cross-diagonal deployed sensors. We implemented the DTW gesture recognition algorithm using extracted data and the time delayed information of peak values. Our experiment results show that average correct classification rate is over 95% on five-gesture scenario.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4
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• pp.49-57
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• 1992

This study was conducted to evaluate physical property change of asphalt cement chromatograms (by HP-GPC) were experimentally obtained from 3 types of AC-20 virgin ACs, 5 and 24-hour artificially aged ACs, and naturally aged 4 ACs that were recovered from 4 different roads. Absolute viscosity, kinematic visoosity and penetration were the physical properties tested. THF was used for mobil phase and RI detector was used as a detector for Hp-GPC testing. Correlation between each physical property change and the chromatogram variation was evaluated. Each chromatogram was divided into ten-equal-time slices. The percentage areas of 10 slices and each physical property were used for statistical correlation evaluation. Statistical analysis results showed that eaoh physical property had a strong correlation with the chromatogram characteristics. Aging was identified as a mechanism of change of molecular size distribution - increasing large size molecules and reducing coresponding samll size molecules.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.187-194
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• 2016

The purpose of this study was to analyze temperature distribution characteristics using a model swine housing for temperature sensor adjustable positioning and developed a sensor and controller embedded exhaust fans utilizing ICT fusion technology for windowless swine housing. Temperature measured by the sensor attached on the exhaust fan was also determined that there is no problem, the temperature is located in the upper fan given the measured errors shown in the 1℃ temperature difference between the lower temperature than the other positions in the model swine housing. The performance of the exhaust fan at maximum output was found to be 1920rpm, air flow rate 125㎥/min. When the open area ratio of 70% one proper air volume of the exhaust fan was found to be 75㎥/min, 60pa. Maximum efficiency in all of the output of the exhaust fan is exhibited at about 70% open area ratio of the damper. The number of revolution of the exhaust fan was 1920rpm when the output was a maximum of 100%. AC output phase of the pulse duty ratio change of the controller was shown to change without delay. It was determined that the instant fan speed control is possible.

• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.37-45
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• 2002

Background: Diffuse panbronchiolitis(DPB) is a chronic inflammatory lung disease that presents as coughing, copious sputum, exertional dyspnea, which progresses to bronchiectasis. The pathogenesis of bronchiectasis is controlled by inflammatory mediators, which are closely related to mucus hypersecretion, goblet cell dysplasia. In recent studies, the epidermal growth factor receptor(EGFR) system was reported to be associated with this process. It was hypothesized that a relationship exists between goblet cell dysplasia, EGFR expression, and inflammatory mediators produced by neutrophil. Method: Alcian blue/periodic acid -Schiff(AB/PAS) stain, MUC5AC, EGFR, CD16 immunohistochemical stain were examined to investigate a role for the EGFR system in a mucus hypersecretion in DPB using the lung biopsy specimens from 13 DPB patients and 6 controls. Results : In the DPB group, the AB/PAS and MUC5AC -stained areas were $8.31{\pm}3.36%$, $11.46{\pm}4.68%$, respectively. In the control group, the AB/PAS- and MUC5AC-stained areas were $50.5{\pm}5.77%$, $53.3%{\pm}6.67%$, which was significantly larger than in the DPB group (each comparison, p<0.05). The percentage of EGFR expression was $9.54{\pm}4.95%$ in the DPB group, but zero in of the control group. The extent of neutrophilic infiltration was $71.92{\pm}3.71$/5HPF in the DPB group and $45.0{\pm}5.73$/5HPF in the control group, which was statistically significant(p=0.002). Conclusion: The EGFR system is highly related to goblet cell dysplasia, mucus hypersecretion and neutrophilic inflammation in DPB.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.235-240
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• 2008

Purpose: At the beginning of PET/CT, Computed Tomography was mainly used only for Attenuation Correction (AC), but as the performance of the CT have been increase, it could give improved diagnostic information with Contrast Media. But it was controversial that Contrast Media could affect AC on PET/CT scan. Some submitted thesis' show that Contrast Media could overestimate when it is for AC data processing. On the contrary, the opinion that Contrast Media could be possible to affect the alteration of SUV because of the overestimated AC. But it does not have a definite effect on the diagnosis. Thus, the affection of Contrast Media on AC was investigated in this study. Materials and Methods: Patient inclusion criteria required a history of a malignancy and performance of an integrated PET/CT scan and contrast- enhanced CT scan within a 1-day period. Thirty oncologic patients who had PET/CT scan from December 2007 to June 2008 underwent staging evaluation and met these criteria. All patients fasted for at least 6 hr before the IV injection of approximately 5.6 MBq/kg (0.15 mCi/kg) of $^{18}F$-FDG and were scanned about 60 min after injection. All patients had a whole body PET/CT performed without IV contrast media followed by a contrast-enhanced CT on the Discovery STe PET/CT scanner. CT data were used for AC and PET images came out after AC. The ROIs drew and measured SUV. A paired t-test of these results was performed to assess the significance of the difference between the SUV obtained from the two attenuation corrected PET images. Results: The mean and maximum Standardized Uptake Values (SUV) for different regions averaged over all Patients. Comparing before using Contrast Media and after using, Most of ROIs have the increased SUV when it did Contrast Enhanced CT compare to Non-Contrast enhanced CT. All regions have increased SUV and also their p value was under 0.05 except the mean SUV of the Heart region. Conclusion: In this regard, the effect on SUV measurements that occurs when a contrast-enhanced CT is used for attenuation correction could have significant clinical ramifications. But some submitted thesis insisted that the percentage change in SUV that can determine or modify clinical management of oncology patients is small. Because there was not much difference that could be discovered by interpreter. But obviously the numerical change was occurred and on the stage finding primary region, small change would be base line, such as the region of liver which has greater change than the other regions needs more attention.