• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.942-945
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• 2010

분산형 전원은 에너지 실수요자 근처 혹은 건물 내부에 소형 발전설비(태양광, 풍력 발전을 포함하는 신재생에너지 발전)를 설치해 에너지 손실과 송 배전 설비를 줄이려는 노력에서 출발했다. 최근 세계적으로 기후 환경 변화에 대처하기 위해 다양한 신재생에너지를 활용하기 위한 댁내 분산형 전원 환경 시대를 예고하고 있다. 특히 태양광, 풍력 발전은 댁내에 설치하기 용이하고 가장 경제성이 뛰어나 많은 기업들이 적극적으로 사업에 진출하고 있다. 하지만 풍력 발전의 경우 바람의 세기에 따라 발전량의 변화가 심하고, 태양광은 일사량 및 일조량의 영향을 많이 받기 때문에 기후 상황에 따라 출력이 불안정하다는 단점이 있기 때문에 균일한 전력품질을 제공하기 위해 해결해야 할 기술적인 과제를 가지고 있다. 본 논문에서는 댁내에서 운용이 용이한 풍력 에너지, 태양광 에너지 및 기존 전력으로 구성되는 분산형 전원시스템에서 기후변화에 민감한 신재생에너지 발전량의 예측 방법에 대해 제안한다. 이를 바탕으로 효율적인 분산전력 관리를 가능하게 하며, 궁극적으로 제로에너지 홈을 구현하기 위한 기본 요소 기술을 제공하는 것이 본 논문의 목표이다.

• Journal of Power Electronics
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• 제11권4호
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• pp.408-417
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• 2011

The plug-in hybrid electric vehicles (PHEVs) are specialized hybrid electric vehicles that have the potential to obtain enough energy for average daily commuting from batteries. The PHEV battery would be recharged from the power grid at home or at work and would thus allow for a reduction in the overall fuel consumption. This paper proposes an integrated power electronics interface for PHEVs, which consists of a novel Eight-Switch Inverter (ESI) and an interleaved DC/DC converter, in order to reduce the cost, the mass and the size of the power electronics unit (PEU) with high performance at any operating mode. In the proposed configuration, a novel Eight-Switch Inverter (ESI) is able to function as a bidirectional single-phase AC/DC battery charger/ vehicle to grid (V2G) and to transfer electrical energy between the DC-link (connected to the battery) and the electric traction system as DC/AC inverter. In addition, a bidirectional-interleaved DC/DC converter with dual-loop controller is proposed for interfacing the ESI to a low-voltage battery pack in order to minimize the ripple of the battery current and to improve the efficiency of the DC system with lower inductor size. To validate the performance of the proposed configuration, the indirect field-oriented control (IFOC) based on particle swarm optimization (PSO) is proposed to optimize the efficiency of the AC drive system in PHEVs. The maximum efficiency of the motor is obtained by the evaluation of optimal rotor flux at any operating point, where the PSO is applied to evaluate the optimal flux. Moreover, an improved AC/DC controller based Proportional-Resonant Control (PRC) is proposed in order to reduce the THD of the input current in charger/V2G modes. The proposed configuration is analyzed and its performance is validated using simulated results obtained in MATLAB/ SIMULINK. Furthermore, it is experimentally validated with results obtained from the prototypes that have been developed and built in the laboratory based on TMS320F2808 DSP.

• 한국정보통신학회논문지
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• 제14권8호
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• pp.1836-1842
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• 2010

센서네트워크는 유비쿼터스 환경을 실현할 수 있는 기술로서, 최근 무인 경비 시스템이나 에너지 관리, 환경 모니터링, 홈 자동화, 헬스케어와 같은 다양한 분야에 적용 가능하다. 하지만 센서네트워크의 무선 통신 특성은 도청과 전송 메시지에 대한 위변조, 서비스 거부 공격에 취약하다. 현재 센서네트워크 상에는 안전한 통신을 위해 ECC(elliptic curve cryptography)를 통한 PKC(public key cryptography)암호화 기법이 사용된다. 해당 기법은 RSA에 비해 작은 키길이를 통해 동일한 암호화 강도를 제공하기 때문에 제한된 성능을 가진 센서상의 적용에 적합하다. 하지만 ECC에 요구되어지는 높은 부하 때문에 센서상의 구현을 위해서는 성능개선이 필요하다. 본 논문에서는 센서 상에서의 ECC를 가속화하기 위해 ECC연산의 핵심연산인 곱셈에 대한 최적화 기법을 제안한다.

• 대한지역사회영양학회지
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• 제9권3호
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• pp.315-325
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• 2004

This study was conducted to develop the standard breakfast menu for those weak groups having insufficient breakfast intake. The following three target groups are classified as: 16-19 years old high school male student, 20-29 years old female who have job or college students, 20-29 years old male or female who have job (double income family). While developing menus for each target groups, we applied several basic guidelines for meal planning as follows: Nutrient intake level was set to $\graction one-Third$ of RDA, while the energy level to $\fraction one-quarter $ of RDAs. Most Sequent meal pattern of Koreans was adapted; Suitabilities of appropriate serving size and cost for middle-income families were considered; Domestic foods and ingredients were used. We developed 24 menus summed by 2 menus for each season and three target groups. When evaluating the menus, most of the breakfast menus were sufficient of nutrients as a meal for the subjects. Three food groups such as grain/starch group, meat/fish/egg/bean group, vegetable/fruit group were included in all menus. Even though milk/dairy products group was not excluded for some menus, other calcium substitutes like anchovies were used. Oil/nut/sugar group was used to a minimum. The average number of foods for each menu was 12.8, which ranged from 10 to 17 depending on the menus. The average weight of the menus including soup was 822 g, 633 g and 730 g for each target group, respectively. The average price of the menu ranged from 2,000 to 3,500 won per person. The above results could be applied at home as well as foodservice institutes and furthermore could offer information for developing breakfast-substituting food products.

• 한국광학회지
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• 제12권2호
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• pp.135-142
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• 2001

최근 플라스틱 광섬유(Plastic Optical Fiber, POF)가 홈 네트워크(Home Network) 및 LAN(Local Area Network)의 새로운 통신채널로 등장하였다. 특히 PMMA 계에 기반을 둔 언덕형 굴절률 분포 플라스틱 광섬유(Graded Index Plastic Optical Feiber)는 500nm와 650nm 근처에서 아주 적은 손실을 가지므로 이 파장영역에서의 광원으로서 극초단 광펄스 생성이 요구되고 있다. 본 연구에서는 650nm InGaAIP FP(fabry perot) LD와 간단한 RF(radio frequency)소자들을 이용한 회로를 구성하고 이득스위칭 기술을 사용하여 1GHz의 펄스 반복율을 가지고 33.3psec 정도의 짧은 반치선폭(FWHM)을 가지는 광펄스를 생성시키는데 성공하였다. 이득스위칭 된 광펄스는 주입되는 직류전류(DC bias current)와 변조되는 주파에 따라 반치선폭은 33.3-82.8 psec, 펄스 에너지는 0.97-9.69pJ의 값을 얻었다. 또한 CW 발진과 이득스위칭 된 광펄스의 스펙트럼 폭은 각각 0.44nm, 150nm로 됨을 측정하였다. 이러한 결과를 가지는 연속적인 광펄스는 직류전류와 VCO에 의한 변조주파수의 적절한 선택에 따라 초고속 근거리 광통신분야 뿐만 아니라 여러 가지 초고속 광소자 및 전자소자의 특성평가 등에 응용될수 있을 것으로 예상된다.

• 한국기후변화학회지
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• 제1권2호
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• pp.163-177
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• 2010

본 논문은 1,185세대가 거주하고 있는 공동주택을 대상지로 하여 정부지원제도인 '태양광주택보급사업'과 '발전차액지원제도'를 각각 활용하여 PV 시스템 도입을 도입할 경우의 경제성을 비교 분석하였다. 각 시나리오별 분석 결과, 수익으로 전력판매수익 만을 고려한 경우, NPV가 보조금 지원제도는 -560백만원으로 분석되었고, 발전차액지원제도는 -87백만원으로 분석되었다. 전력판매수익과 온실가스 배출권 수익을 함께 고려한 경우에도 NPV가 보조금 지원제도는 -530백만원으로 분석되었고, 발전차액지원제도는 -57백만원으로 분석되어 모두 수익성이 없는 사업으로 나타났다. PV 시스템 도입으로 인해 회피되는 대기오염물질로 인한 사회적 편익을 함께 분석한 결과도 그 편익이 미미하여 여전히 경제성이 없는 것으로 평가된다. 할인율과 초기비용의 변동을 기준으로 민감도 분석을 한 경우, 보조금 지원제도의 경우에는 할인율을 3%까지 낮추고, 초기 설비 투자 비용을 정부 제시기준 단가인 721만원/kW에서 650만원/kW로 낮춘 것에 배출권 수익까지 포함한 경우에도 여전히 사업성이 없는 사업으로 나타났지만, 발전차액 지원 제도의 경우에는 배출권 수익을 포함하지 않고도 할인율 약 7.2%와 초기 설비투자비용 684만원/kW에서 각각 손익분기점이 되면서 수익성이 있는 사업으로 전환되어 발전차액지원제도가 PV 시스템 도입에 훨씬 유리한 것으로 나타났다. 사회적 비용을 고려한 경우에는 보조금제도를 활용한 모든 시나리오는 배출권 수익과 환경편익을 모두 포함하여도 수익성이 없는 사업으로 나타났으나, 발전차액지원제도를 활용한 시나리오의 경우에는 배출권 수입을 제외하고도 할인율 7.2%와 초기비용 686만원/kW가 각각 손익분기점이 되면서 수익성이 있는 사업으로 전환되었다. 본 연구의 결과, 할인율이 7.2% 이하가 되든지 초기 설비투자비용이 정부 제시 기준 단가보다 4.9% 낮아진다면 발전차액지원제도 하에서도 공동주택의 태양광발전시스템이 경제성을 갖는 것으로 분석되었다. 우리나라의 높은 아파트 보급률과 PV 시스템 도입으로 발생하는 긍정적인 사회적 환경적 편익을 고려하면 공동주택의 태양광 시설 설치에 대해 발전차액지원제도를 확대 지원함으로써 화석연료의 사용을 절감하고, 온실가스 배출을 줄여서 에너지자급도 제고와 기후변화에 대한 대응을 통해 녹색성장에 기여할 수 있을 것으로 생각된다.

• 한국대기환경학회지
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• 제29권5호
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• pp.668-681
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• 2013

The Korean government announced a national mid-term target to reduce 30% of greenhouse gas (GHG) emissions from business-as usual (BAU) level by 2020 in a voluntary and independent manner. In this study, we examined the $CO_2$ mitigation potential and conducted an economic effect analysis of green living actions in households in Korea. We also proposed some ways to implement green life to achieve the national target. If green lifestyle takes root in households nationwide, $CO_2$ emission would be reduced to 27.3% of the emission in 2007. This would save the country about 4.93 trillion won per year and each household could save about 300,000 won per year, which accounts for about 0.5% of GDP (as of 2007). Considering the five-year plan for green growth to invest 2% of GDP in green growth every year, this would not only reduce the economic burden on households, industries and the country but also increase economic growth potential by reinvesting the saved resources into green growth. Heating and lighting would be the greatest contributor to GHG mitigation of green life in the residential sector. It means we could achieve the national goal by reducing unnecessary heating and lighting and using energy-saving electric home appliances. The implementation of green living actions would reduce a significant amount of greenhouse gas emissions, ultimately relieving the burden on businesses to reduce GHG emissions. And it is one of the most cost-effective mitigation tools in order to achieve the mid-term GHG mitigation goal.

• 한국지역사회생활과학회지
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• 제17권3호
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• pp.159-174
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• 2006

The purpose of this study is to provide information searching for health promotion, nutrition improvement, and health care of the impaired elderly by ADL(Activity of Daily Living) and IADL(Instrumental Activity of Daily Living). The subjects were divided into the Assistant Needed Group and No Assistant Needed Group for living in line with the responses of ADL(10 items like dressing, washing, move etc.) and IADL(10 items like housekeeping, using transportation, shopping, Phone call etc.). Survey was made for health behavior, health risk habit, dietary management status and diet intake by 24 hr-recall and questionnaire method. 242 subjects were collected in 12 cities or Gun districts in Gyeonggi Province, S. Korea. Survey was carried out by regional home extension workers using interview method. Statistical analyses were made using SAS (Version 8.1). Chi-Square Tests and General Linear Models. The subjects of impaired ADL elderly was 26.5% and it composed 30% of the total male and 22.2% of the total female. The demographic status of the impaired ADL elderly showed no difference from that of the normal elders, elementary school educated (73.4%), with spouse (43.8%) or with adult children(37.5%), using monthly living cost of 500-1,000 thousand won(35.9%). Mean age was 74.05 years compared to 72.25 years of normal elders. However, there was no significant difference from the normal and impaired ADL group, regular exercise(60.0%), with walking (90.0%), no-smoke(54.7%) and no-drink(48.4%). Kind of disease was not different from the one in impaired and normal group, with cardiovascular disease(32.3%), with diabetes mellitus(8.1%), joint lumbago neuralgia(32.3%) and osteoporosis(9.7%). Gastrointestinal complaints of the impaired ADL group were nausea(57.8%), chronic indigestion (23.4%), constipation (14,0%) and vomiting(3.7%). Sleeping time required for the impaired was longer than that for the normal group by 10hours(4.7%) or 8-10hours(20.3%), which consisted 1.7% and 16.6% respectively. Nutrient intake of the impaired ADL group was low compared to normal range elders: Energy(1260kca1), Protein(52.75g). There was gender difference in nutrient intake; the male impaired group showed no significant difference from the normal group but it was significantly lower in female impaired group. These results suggest that low quality of life and low economic status of the impaired ADL elderly require congregate meal in village hall to cover the lack of side dishe variety. And nutrition education program including community assistance would be required for the impaired ADL elderly together with the sufficient food and exercise practice. By operating nutrition education program, the impaired ADL elderly would maintain more enhanced quality of life and ameliorate the ADL capability.

• 한국지역사회생활과학회지
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• 제17권1호
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• pp.141-154
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• 2006

The purpose of this study is to provide the information of the aged olds for which basic data are almost no available. The subjects were divided on the base of age 75. The elderly under 75 were named 'the young olds' and over 75 were 'the aged olds'. The aim of this research is to promote health and to improve nutrition, and the survey was made for health promotion behaviors, habits against health risk, dietary management status and diet intake. And it was conducted by 24 hr-recall method and analyzed by nutrients intake. 242 subjects were collected in 12 cities or counties in Gyeonggi Province and 20 elderly people (10 male and 10 female) were selected out of 1 village in each district. Questionnaire about health behavior and dietary management was carried out by interview method through regional home extension workers. Statistical analyses were made by SAS (version 8.1) and Chi-square tests and General Linear Models were used. Out of the subjects the aged olds over 75 was 31.9%, elementary school educated (93.5%), with spouse (40.3%), with adult children(28.6%), monthly living cost of 500-1,000 thousand won(40.3%). Mean age was 78.82 years compared with 69.75 years of the young olds. 46.8% of the aged olds used monthly pocket money over 1000 won and it was lower than 63.3% of the young olds. Only half of the aged olds had regular exercise of walking (77.8%) or with athletic equipment (17.8%). However, the young olds did more frequent walking (82.1 %) and less exercise with athletic equipment (4.8 %), which was significantly different. Kinds of disease were different with the young or the aged olds, as more proportion of cardiovascular disease(37.9%) for the young olds and joint lumbago neuralgia(41.6%) for the aged olds. Dietary management was good (3 meals per day: 93.4%, fixed mealtime: 72.4%, and regular amount: 79.9%). But there was significant difference in side dish varieties and kinds of snacks; for the aged olds only 8% had over 5 sorts (compared with 18.8% of the young olds) and the kinds of snacks were cookie, candy, juice, carbonated beverage for the aged olds (compared with noodle, milk, soybean-milk for young olds). The ratio of nutrients intake (energy, riboflavin and niacin) with RDA was significantly higher for the aged olds than that of the young olds. The surveyed subjects had no difficulties in Activities of Daily Living (ADL), but some of the aged olds had difficulties in Instrumental Activities of Daily Living (IADL) like housekeeping, using transportation, going shopping and making phone calls. These results suggest that low quality of life is linked with low economic status of the rural elderly and congregate meal at village hall would be required because of the lack of side dishes variety for the aged olds. And nutrition education program about good snacks and exercise practice would be needed for the aged olds. By operating nutrition education program the aged olds would enjoy better quality life maintaining or ameliorating IADL abilities.

• 한국지역사회생활과학회지
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• 제17권1호
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• pp.123-139
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• 2006

The purpose of this study is to search how to promote health and improve nutrition and health care of the elderly people in rural area. Behaviors for health promotion and habits against health risk were surveyed. Dietary management was analyzed for surveyed nutrient intake by 24 hr -recall method. 242 subjects were collected in 12 cities or counties in Gyeonggi Province and 20 elderly people (10 male and 10 female) were selected out of 1 village in each district. Questionnaire for health behavior and dietary management was carried out by trained interviewers. Statistical analyses were made by SAS (version 8.1) and Chi-square tests and General Linear Models were used. Characteristics of the elderly people were 61-74 year-olds (68.2%), elementary school educated (78.4%), with spouse (51.7%), monthly living cost of 500-1,000 thousand won(43.4%), and monthly pocket money of 50-100 or 100-200 thousand won(33.5%, 26.5%). 41.4% of the subjects checked up medical examination regularly. The alcohol drinking status was significantly different according to gender: high no-drink rate of female (52.5%) and low no-drink rate of male (25.6%). Kinds of disease were different according to gender: higher proportion of cardiovascular disease(46.3%) and diabetes mellitus(8.1 %) in male and joint lumbago neuralgia(44.4%) and osteoporosis(8.6%) in female. Gastrointestinal complaints were nausea (69.0%) and chronic indigestion (17.8%). Constipation (12.0%) and vomiting (4.3%) were more frequent in female. Dietary management was good (3 meals per day: 93.4%., dining with family: 72.4%, regular mealtime: 72.4%, and 3-4 times of snacks per week: 44.9%) except side dish taking of 3-4 kinds only. However, almost one-third of the female elderly ate alone (30.6%) which was well compared with one-fifth of the male (19.7%). And food and nutrients intake were not significantly different according to gender except that male elderly's intake of energy and protein was lower than that of female's. The surveyed subjects had no difficulties in Activities of Daily Living (ADL), but some female elderly had some difficulties with Instrumental Activities of Daily Living (IADL) like working at home, using transport, and going shopping. These results suggest that low quality of life linked with low economic status of the rural elderly and that congregate meal at village hall would be required for the female elderly eating alone. For the undernourished male elderly, it would be needed to provide snacks and to establish nutrition and health surveillance system.