• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.78-85
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• 2006

A survey on the fishing gear for octopus drift-line fishing was done in Gangwon-do, Sacheon, Gyeongnam and Hokkaido, Japan, while a survey on the environments of fishing grounds used data from January to August from the Korea east coast farming forecast system of Donghae Fisheries Research and Development Institute. The present situation of fishing was examined with boats engaging in drift-line fishing from March to August in the coastal waters along Gangneung. The fishing tackle for octopus drift-line fishing was made manually, and the size, shape, and weight of the hook and number of shooting used vary according to the fishing time and region. Lead is used as the material for sinkers. As bait, pork fat with skin is mostly used in Gangwon-do. The temperature of the bottom water layer in the coastal fishing ground of Gangneung from April to June ranges from $3.2-12.4^{\circ}C$, which is the optimal temperature for octopuses. During July and August, the temperature ranges from $5.0-20.6^{\circ}C$. The maximum difference between day and night temperatures reached up to $9.2^{\circ}C$. Salinity is generally stable at $33.2-35.324.6%_{\circ}$, which does not affect the inhabitation of octopuses. The octopus catch reached its peak from May to July, while most octopuses weighed less than 1 kg (76.7%). The results show that it is effective to carry out octopus drift-line fishing up to a depth of 40 meters; and that the maximum number of octopuses per line is obtained with an operation time of six hours.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.279-288
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• 1998

This study explored the effect of calcium levels and/or ovariectomy on bone metabolism using female Sprague-Dawley weanling rats as a model . Rats received a low (0.1%) calcium diet for 8 weeks. The rats were then divided into three subgroups that were fed 0.1% ,0.5% and 1.5% calcium diets for 8 weeks after operation. The results of this experiment indicate that body weight gin was higher in ovariectomy groups than in sham groups regardless of calcium level and food intake. Serum Ca and P concentrations were of normal level regardless of calcium level and ovariectomy. Estrogen concentration was low in the ovariectomized group. Serum alkaline phophatase activity and urinary hydroxyproline have been used as markers of bone formation and resorption. These values were increased in ovariectomized groups. The weight, length and breaking force of femur were not significantly different between the groups. Ash, Ca, P and total lipid contents in femur and lumbar were decreased in the groups fed low calcium . Mg content was decreased in the ovariectomy and total protein content was not affected by calcium level and ovariectomy. The effect groups of ovarectomy on calcium contents of bone was more prominent in lumbar than in femur. In conclusion, though low calcium intakes during growth period may retard the attainment of peak bone mass, calcium supplementation after this period increased bone growth and mineral contents, but not significant effect in three calcium levels. Furthermore, calcium intake was shown to have a greater influence on the mineral contents of femur than of lumbar, and removal of endogenous estrogen production by ovariectomy was shown to be more deleterious on the ash and calcium contents of the lumbar than of femur.

• Journal of Korean Neurosurgical Society
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• v.42 no.2
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• pp.97-102
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• 2007

Objective : The authors attempted to evaluate the pattern of the airway narrowing due to prevertebral soft tissue swelling after surgery of the anterior cervical spine and their clinical significances using plain cervical X-ray images. Methods : Twenty-four patients undergoing anterior cervical spine surgery were reviewed from January 2004 to December 2005. Postoperatively, in daily basis, lateral radiograph of the neck was obtained in neutral position. We measured the upper airway diameter above and below the epiglottis level and prevertebral soft tissue diameter every day for a week and finally 2 weeks after surgery using their simple lateral cervical X-ray films. Results : Both airway narrowing and prevertebral soft tissue swelling were maximum in postoperative 2 days, and decreased rapidly in postoperative 7 days. Airway narrowing was aggravated postoperatively but slowly decreased as prevertebral soft tissue swelling diminished. But, the severity of airway narrowing showed no clinical correlations with clinical symptom and radiologic severity. Conclusion : Not all patients who show severe airway narrowing and prevertebral soft tissue swelling on their plain cervical X-ray film complain respiratory insufficiency. But, the patients with undergoing anterior cervical spine surgery should be monitored carefully for respiratory insufficiency, especially during several days following operation because both airway narrowing and prevertebral soft tissue swelling become peak at postoperative 2-3 days.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.473-477
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• 2007

The development of advanced Insulated Gate Bipolar Transistor(IGBT)has enabled high-frequency switching operation and has improved the performance of PWM inverters for motor drive. However, the high rate of dv/dt of IGBT has adverse effects on motor insulation stress. In many motor drive applications, the inverter and motor are separated and it requires long motor feds. The long cable contributes high frequency ringing at the motor terminal and it results in hight surge voltage which stresses the motor insulation. The inverter output filter and RDC snubber are conventional method which can reduce the surge voltage. In this paper, we propose the new low loss snubber to reduce the motor terminal surge voltage. The snubber consists of the series connection of charging/discharging capacitor and the voltage-clamped capacitor. At IGBT turn-off, the snubber starts to operate when the IGBT voltage reaches the voltage-clamped level. Since dv/dt is decreased by snubber operating, the peak level of the surge voltage can be reduced. Also the snubber operates at the IGBT voltage above the voltage-clamped level, the snubber loss is largely reduced comparing with RDC snubber. The proposed snubber enables to reduce the motor terminal surge voltage with low loss.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.420-424
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• 1999

In this paper, an optical switching circuit and several types of all-optical transmitter/receiver circuits which are configured with photodiodes, multiple quantum-well(MQW) optical modulators, and field-effect transistors(FETs) were simulated using PSPICE and their results of these are examined and discussed. 20 $\mu\textrm{m}$ ${\times}$ 20 $\mu\textrm{m}$ of window size was used for the optical modulators and 100 $\mu\textrm{m}$ wide FETs with the transconductance value of 55 mS/mm were used for the simulations. Simulation results clearly show that in order for the high speed operation of the all-optical circuits, the size of each device should be minimized to reduce the parasitic capacitance, the circuits should be designed to operate at the wavelength where the resposivity of photodiodes becomes the maximum peak, and the use of short, high-intensity input optical signal beams is very advantageous.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.758-761
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• 2007

Digital signal processing technique is applied in wide fields such as speech processing, image processing and spectrum analysis. Therefore, in order to do frequency selective operation digital filter is used in stead of analog filter and sharp filter characteristics can be implemented. Since finite impulse response (FIR) digital filter as nonrecursive type represents linear phase response characteristics and is always stable and is used in fields regarding wave information importantly such as data transmission. And due to frequency characteristics, in order to remove the Gibbs phenomenon generating around a discontinuous point, filter is designed through window function method. Therefore, in this paper to improve performance of FIR digital filter, a modified window function was applied. And the proposed method was compared with conventional methods using peak side-lobe and transition properties in simulations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.31-37
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• 2010

In this paper, highly efficient dual-band class-F power amplifiers(PAs) for cellular and WLAN bands are suggested and implemented. For the first step, single-band class-F amplifiers at 840MHz, 2.4GHz are designed using commercial E-pHEMT FETs. The performance of two single band PAs are as much as 81.2% of efficiency with the output power of 24.4dBm with 840MHz PA and 93.5% of efficiency with 22.4dBm from the 2.4GHz. For the dual-band class-F PA, the harmonic controlling circuit with ideal SPDT switch was suggested. The length of transmission line is variable by a SPDT switch. As a results, the operation in 840MHz showed the peak efficiency of 60.5% with 23.5dBm, while in 2.4GHz mode the efficiency was 50.9% with the output power of 19.62dBm. Besides, it is shown that the harmonic controller of class-F above 2Ghz could be implemented on the low cost FR-4 substrate.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.21-26
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• 2014

This paper proposes a frequency reconfigurable antenna which operates at not only LTE but also other currently serviced bands. The high band(1,710-2,170 MHz) performance was satisfied through PIFA structure, and the low band performance through the additional RF Switch by changing the state between SW1 and SW2. When the RF switch is SW1 state, the operation bandwidth is 782-907 MHz (GSM), and 738-861 MHz (LTE) at OFF state. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 0.04-4.68 dBi at the SW1 state and 0.92-1.53 dBi at the SW2 state, respectively. Judging from the results, proposed reconfigurable antenna is expected to be applied to LTE-Advanced mobile terminals since the antenna shows an outstanding performance.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.591-595
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• 1995

Recently, primary lung cancer has increased markedly in incidence and prevalence in Korea. From January 1986 to June 1993, 86 patients were operated and evaluated at the Department of Thoracic and Cardiovascular Surgery, Chungnam National University Hospital. The results are as follows; 1. There were 79 males and 7 females with the peak incidence of 5th and 6th decades of life[75.6% . The age ranged from 13 to 76[mean 56.6$\pm$10.3 years. 2. Symptoms were cough[47.7% , sputum[25.6% , chest pain or dyspnea[18.6% , and hemoptysis or blood tinged sputum[20.9% in order. Symptoms were frequently encountered before hospitalization, but asymtomatic patients were 12.8% in this study. 3. Methods of diagnostic confirmatiom were bronchoscopic biopsy[55.8% , percutaneous needle aspiration[29.1% , suspicious sputum cytology[1.2% , and open biopsy[14.0% . 4. Histopathologically, squamous cell carcinoma[51.2% was the most frequent cell type and adenocarcinoma[26.7% , large cell carcinoma[8.1% , adenosquamous cell carcinoma[3.5% , and the others in order. And TNM stages were Stage I 40.5%, Stage II 15.5%, Stage IIIa 27.4%, and Stage IIIb 3.6%. 5. Methods of operation were pneumonectomy[25.6% , bilobectomy[5.8% , lobectomy[53.4% , segmentectomy[1.2% , and exploration[14.0% . The overall resectability was 86.0% 6. The operative mortality was 2.3% and postoperative complications developed in 7 cases[8.1% . 7. The postoperative follow-up reveals that the overall cumulative survival rates at 1 year, 2 year, 3 year, 4 year, 5 year were 76%, 62%, 43%, 36%, and 27%, respectively.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.249-255
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• 2020

This study developed the health monitoring method of press process using the acoustic emission (AE) sensor and high-pass filter. Also, the AE parameters such as ring-down count and peak amplitude are used. Based on this AE signal, the AE parameters were acquired and was utilized to detect the crack of the specimen. Since the defect detection is difficult due to noise and low magnitude of signal, the signal noise and press operation frequency were checked through the Short Time Fourier Transform(STFT) and damped. High-pass Filtering data was applied to AE parameters to select effective parameters. By using this signal processing techniques, the proposed AE parameters could improve the performance of defect detection in the press process.