• 한국전자파학회논문지
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• 제19권8호
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• pp.854-861
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• 2008

본 논문에서는 효율이 특화된 전력 증폭기를 이용하여 IEEE 802.16e Mobile WiMAX용 고출력 하이브리드 포락선 제거 및 복원 전력 송신기에 대해 기술하였다. Nitronex사의 100-W PEP를 갖는 GaN HEMT 소자를 이용하여 중요한 전력 생성 $V_{ds}$ 구간에 대하여 최대 PAE를 가질 수 있도록 전력 증폭기를 설계하였다. 고출력 응용을 위해서 하이브리드 포락선 제거 및 복원 전력 송신기를 전력 증폭기의 bias fluctuation 문제 및 바이어스 변조기의 stability 문제에 의한 regenerative 오실레이션 문제를 반드시 고려하여 설계되어야 한다. 연동 실험을 위하여, 8.5 dB의 PAPR을 갖는 포락선 신호에 대해 바이어스 변조기는 30 V의 최대 출력 전압 크기를 가지면서 72 %의 높은 효율을 유지하도록 구현되었다. WiMAX 신호를 목표로 구현된 하이브리드 포락선 제거 및 복원 전력 송신기는 41.25 dBm의 출력 전력에서 38.8%의 놓은 PAE 성능을 얻었다. 또한, 디지털 전치 왜곡 기술을 적용함으로써 전력 송신기의 RCE 성능은 -34.5 dB를 기록하여 WiMAX 신호의 선형화 지표를 만족시킬 수 있었다. 본 연구는 2.655 GHz 주파수 대역에서 처음으로 구현된 WiMAX용 고출력 하이브리드 포락선 제거 및 복원 전력 송신기에 관한 것이다.

• Journal of Nutrition and Health
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• 제36권2호
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• pp.154-166
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• 2003

To investigate the effects of isoflavone supplementation on both bone mineral density and hormone variation in premenopausal women who had decreased bone mass, the 24 subjects were divided into two groups: one was the underweight group, consisting of 13 subjects, and the other was the normal weight group consisting of 11 subjects. For each group, we investigated the effects of isoflavone supplementation of 90 mg/day on both bone mineral density and hormone variation during 3 menstrual cycles. Anthropometric measurements, dietary recall, and analyses of blood and urine were assessed from baseline to post-treatment. The results were as follows: The average age of the underweight group was 21.8 years old and that of the normal weight group was 23.2 years old. The comparative results for the two groups at baseline were as follows: Onset of menarche, menstrual cycle, and menstrual length were not significantly different between the groups. Serum protein, total, HDL-, LDL-cholesterol, triglyceride, Ca, P, Mg, Cu, and Zn level were not significantly different between the groups. Serum estradiol, SHBG, LH, and FSH level were also not significantly different between the groups. Lumbar spine BMD by T scores of the underweight group was significantly lower than that of the normal weight group. Serum osteocalcin, urinary DPD, and urinary pH were not significantly different between the groups. The comparative results for the two groups at post-treatment were as follows: From baseline to post-treatment, the intake of energy, nutrients and isoflavone in food did not significantly change in either group. Serum protein, total cholesterol, HDL-, LDL-cholesterol, and triglyceride levels did not significantly change in either group. Serum Ca, Cu, and Zn levels were significantly lower in both groups and serum Mg level significantly decreased only in the underweight group. Serum estradiol levels were significantly lower in both groups, but serum SHBG, LH, and FSH levels did not significantly change in either group. Lumbar spine BMD by T score of the underweight group significantly increased to 15%, but that of the normal weight group did not significantly change. Serum osteocalcin of the underweight group significantly increased to 28%, while that of the normal weight group significantly increased to 40%. Urinary DPD of the normal weight group significantly increased to 12%. The results show that the BMD of the underweight group was lower than that of the normal weight group. Therefore, the underweight group had a disadvantage in obtaining maximum bone mineral density. The results also show that isoflavone supplementation during 3 menstrual cycles was effective in increasing the bone mineral density of the lumbar spine and affected bone metabolism markers in premenopausal underweight women. Therefore, it can be concluded that sufficient intake of isoflavone could be helpful in preventing decreases in bone mass among premenopausal women, especially underweight women.

• Journal of Nutrition and Health
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• 제41권3호
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• pp.216-223
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• 2008

본 연구는 0.03%의 카페인 함유 식이를 폐경모델인 난소절제쥐에서 6주간 섭취시켜 골밀도와 골무기질함량에 미치는 영향을 아래와 같이 요약하였다. 1) 체중증가량은 난소절제군이 Sham군에 비해 유의적으로 높았으며 각 군내에서 카페인 섭취에 따른 차이는 없었다. 2) 혈 중 칼슘 농도는 난소절제군내에서 카페인군이 대조군보다 유의적으로 낮게 나타났다. 3) 혈 중 ALP는 Sham군과 난소절제군 모두에서 카페인 군이 대조군보다 높은 경향을 나타내었다. 혈중 Osteocalcin은 Sham 군과 난소절제군, 그리고 각 군내에서 카페인 섭취여부에 따라 유의적인 차이를 나타내지 않았다. 4) 요 중 칼슘 및 인의 농도, 요 중 Deoxypyridinoline(DPD)와 crosslinks value는 Sham 군과 난소절제군, 그리고 각 군내에서 카페인 섭취여부에 따라 유의적인 차이를 나타내지 않았다. 5) 척추골밀도는 Sham군에 비해 난소절제군이 유의적으로 낮았고, 난소절제군내에서 카페인 첨가군과 대조군간에 차이가 없었다. 6) 대퇴골밀도와 대퇴 골무기질 함량은 Sham군과 난소 절제군 간의 차이는 없었고, 각 군내에서 식이에 따른 차이도 없었다. 따라서 카페인 0.03% caffeine 섭취는 난소절제쥐에서 6주간 섭취 시킨 경우 척추와 대퇴골밀도에 부정적 영향을 미치지 않는 것으로 나타났다.

• Journal of electromagnetic engineering and science
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• 제11권1호
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• pp.16-26
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• 2011

This paper presents high power and high efficiency Doherty amplifiers for 2.345 GHz wireless broadband (WiBro) applications that use a Nitronex 125-W ($P_{3dB}$) GaN high electron mobility transistor (HEMT). Two- and three-way Doherty amplifiers and a saturated Doherty amplifier using Class-F circuitry are implemented. The measured result for a center frequency of 2.345 GHz shows that the two-way Doherty amplifier attains a high $P_{3dB}$ of 51.5 dBm, a gain of 12.5 dB, and a power-added efficiency (PAE) improvement of about 16 % compared to a single class AB amplifier at 6-dB back-off power region from $P_{3dB}$. For a WiBro OFDMA signal, the Doherty amplifier provides an adjacent channel leakage ratio (ACLR) at 4.77 MHz offset that is -33 dBc at an output power of 42 dBm, which is a 9.5 dB back-off power region from $P_{3dB}$. By employing a digital pre-distortion (DPD) technique, the ACLR of the Doherty amplifier is improved from -33 dBc to -48 dBc. The measured result for the same frequency shows that the three-way Doherty amplifier, which has a $P_{3dB}$ of 53.16 dBm and a gain of 10.3 dB, and the saturated Doherty amplifier, which has a $P_{3dB}$ of 51.1 dBm and a gain of 10.3 dB, provide a PAE improvement of 11 % at the 9-dB back-off power region and 7.5 % at the 6-dB back-off region, respectively, compared to the two-way Doherty amplifier.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (D)
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• pp.100-102
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• 2006

본 논문에서는 분산응용 개발 및 관리에 대한 사용자의 요구사항을 만족시킬 수 있는 분산서비스 맞춤형 소프트웨어 아키텍쳐인 분산객체그룹 프레임워크를 제안한다. 분산객체그룹은 응용을 구성하는 분산객체들을 하나의 논리적인 그룹으로 관리하며, 분산객체그룹 프레임워크는 분산응용의 개발자 관점에서 응용의 범위를 효율적으로 정의할 수 있을 뿐 아니라, 프레임워크의 지원 분산서비스를 응용과 독립적으로 적용할 수 있다. 프레임워크의 컴포넌트로 그룹관리자와 보안모듈, 모바일프락시, 컨텍스트제공자 및 DPD-Tool을 포함하며, 실시간 서비스를 위한 실시간관리자, 스케쥴러를 갖는다. 본 프레임워크는 분산서비스 지원 컴포넌트들의 상호작용으로 적응성(adaptability), 확장성(scalability), 보안성(security), 이동성(mobility) 및 신뢰성(reliability)을 제공하며, 분산응용을 개발 시 필요한 분산서비스를 모듈 단위로 선택하여 실제 응용 수행 시 선택한 분산서비스를 통해 그 수행성이 보장되도록 한다.

• 농촌의학ㆍ지역보건
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• 제32권1호
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• pp.41-51
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• 2007

Objectives: The aim of this study was to evaluate the effects of exercise on the cardiovascular and musculoskeletal variables and quality of life in elderly women. Methods: The study subjects were 22 in experimental group and 21 in the control group, all of who were aged 65 years and over. The subjects in the experimental group were under an exercise program 3 times a week for one year. To assess the effects of exercise in the study group, blood pressure, heart rate, lipid profile, bony metabolism, grip strength, flexibility, reaction time, and quality of life were measured. Results: Exercise showed the significant differences between experimental and control groups on the variables of the diastolic blood pressure, HDL-cholesterol, urinary deoxypyridinoline, flexibility, and quality of life. Compared to before the exercise in the study group, the urinary DPD level and quality of life were significantly improved at 3 months, and diastolic blood pressure, serum HDL-cholesterol, and flexibility were significantly improved by 1 year. Conclusions: The study results underscore the efficacy of exercise and the need for regular exercise programs that are designed for older persons.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.117-120
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• 2000

본 연구는 4가지 종류의 재조합 발광성 미생물을 이용하여 내분비계 장애물질로 알려진 여러 가지 물질에 대한 cellular toxicity를 유전자 손상, 단백질 손상, 산화적 손상, 생물막 손상으로 구별하여 확인하였다. 4가지 발광성 미생물의 반응성에 따라 내분비계 장애물질의 독성 형태를 규명할 수 있었고, 생명체에 미치는 독성 정도를 확인할 수 있었다. 또한 유전자 손상을 탐지할 수 있는 DPD2794의 경우 유전자 손상을 일으키는 형태에 따라 두 그룹으로 보다 세분화가 가능하였다. 따라서 본 연구결과를 바탕으로 내분비계 장애물질이 호르몬 교란으로 인한 피해뿐만 아니라 cellular toxicity로 인한 피해 역시 입힐 수 있는 것으로 확인하였고, 이들 발광성 박테리아를 이용하여 그 독성 형태를 정확하게 파악할 수 없었던, 유해 물질들의 분류를 위한 screening method로의 개발 역시 가능할 것이다.

• The Journal of Korean Physical Therapy
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• 제18권4호
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• pp.11-17
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• 2006

Purpose: This study aims to suggest clinical basis of physical therapy to skeletal system complication in type II diabetic patients through a variety of analysis methods. Methods: 75 subjects(type II diabetic patients; age from 40 to 80) of this study were participated in BMD(Bone Mineral Density) and Dual energy X-ray absorptiometry, blood test to their skeletal system. Results: Incidence of osteopenea was higher than normal group as women(91.2%) and men(53.5%) in diabetes group. However, women were showed no significantly difference in comparison group. Above age 60(in diabetes group; men and women) showed to highly incidence of osteopenea as well as significantly difference in osteopenea(peripheral neuropathy). As a result of analyzing blood through presence and absence of osteopenea in diabetes group, men were showed significantly difference in DPD/creatinine ratio and women were showed significantly difference in Alkaline phosphatase, Corrected Calcium. Conclusion: This study shows that decreased BMD and increased osteopenea through type II diabetes. Women were particularly lower BMD and higher incidence of osteopenea than men and men influence of type II diabetes on change of BMD was greater than women.

• Nutrition Research and Practice
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• 제3권2호
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• pp.108-113
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• 2009

Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups, One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined, Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations, Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.

• 센서학회지
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• 제20권6호
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• pp.368-374
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• 2011

A microfluidic device for real-time monitoring of residual free chlorine and pH in water based on optical absorption is proposed. The device consists of a serpentine micromixer for mixing samples with a reagent, and a photodiode and light emitting diode(LED) for the detection of light absorbance at specific wavelengths, determined for specific reagent combinations. Spectral analyses of the samples mixed with N, N'-diethyl-p-phenylenediamine(DPD) reagent for chlorine determination and bromothymol blue(BTB) for pH measurement are performed, and the wavelengths providing the most useful linear changes in absorbance with chlorine concentration and pH are determined and used to select the combination of LED and photodiode wavelengths for each analyte. In tests using standard solutions, the device is shown to give highly reproducible results, demonstrating the feasibility of the device for the inexpensive and continuous monitoring of water quality parameters with very low reagent consumption.