• 대한전자공학회논문지TC
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• 제43권7호
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• pp.50-59
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• 2006

서비스 사업자와 통신 제조업체에 의해 선도되는 새로운 통신 패러다임은 무선 이동 통신망을 AII-IP(Internet Protocol) 망으로 빠르게 전환하도록 하고 있다. 이러한 패러다임에서 이기종망간 IP의 개방 접근성으로 인해, 가입자에 대한 인증과 세션 키를 제공하는 것이 중요한 연구 과제들 중의 하나가 되었다. 본 논문에서는 이기종 무선 이동망들의 인증 처리 절차를 소개하고, 모든 이동 망간 연동을 안전하게 지원하면서, 기존 망에 대한 인증 호환성(Backward Compatibility)을 제공하는 통합 이동 인증 서버(IMAS; Integrated Mobile Authentication Server)를 제안한다. 특별히, IMAS의 디자인에 있어서 무선 인증 상호 연동 기법, 키 관리 기법 및 극복되어야 할 쟁점 사항들을 제시한다. 세션 키를 생성하는 인증 알고리즘의 성능 결과를 분석하고 평가한다. 또한, IMAS의 실험 환경을 구축하여 성능(TPS; Transaction Per Second) 결과를 분석하며 평가한다. IMAS는 기존망의 기능과 효율에 대한 보상없이 이기종 무선 이동망 간 연동이 가능하도록 하였고, 분산된 DB(Data Base) 통합으로 인해 망간 데이터 중복성과 불일치성을 줄였다.

• 한국대기환경학회지
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• 제15권4호
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• pp.403-415
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• 1999

To properly assess air pollution levels, application of quality assurance and quality control(QA/QC) is believed to be an essential step. In order to cope with such scientific principle, a field study was designed with an aim of comparing: 1) the methods of calibration for airborne pollutants and 2) the protocols developed for their measurements. Measurements were made at Han Yang University, Seoul during 29 May through 1 June 1998 under the management of the Division of Measurements and Analysis(DMA) of Korean Society for Atmospheric Environment(KOSAE). In this work, we report our results of intercomparative measurements on several gaseous criteria pollutants that were investigated mainly by the two institutes-Seoul National University(SNU) and the Korean Research Institute for Standards and Science(KRISS). Although measurements of major gaseous pollutants had been made routinely by many scientific institutes and organizations in Korea, most scientists involved in those studieswere obliged to do their experiments on the basis of their own procedural steps spaning from the preparation of gaseous standards to the methodological selections for the calibration. Hence, this campaign offered a unique opportunity to examine many important aspects on the measurements of these important gaseous pollutants. In the course of our study, we investigated the compatibility of data sets obtained by the two institutes in concert with reference data sets collected concurrently from a government-managed monitoring station. On the basis of our study, we conclude that different data sets made by different participants during this campaign agree well within the reasonable range of uncertainties.low, which indicated that during this period the potential acidity of precipitation was high but the neutralizing capacity was low. For Spring, pAi was very low but pH was slightly high. This was likely due to the large amount of $CaCO_3$ in the soil particles transported over a long range from the Chinese continent that were incorporated into the precipitation, and then neutralized the acidifying species with its high concentraton.

• 여성건강간호학회지
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• 제27권3호
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• pp.220-229
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• 2021

Purpose: The world saw a shift into a new society consequent to the coronavirus disease 2019 (COVID-19), which made home quarantine mandatory for a person in close contact with those who tested positive. For children, however, home quarantine was not limited only to themselves but parents, especially mothers were involved and required to quarantine. This qualitative study aims to explore and understand mothers' experience and their related psychosocial issues while caring for their school-aged children in Korea, who had to home quarantine after coming in close contact with COVID-19 positive individuals. Methods: Data were collected from October 2020 to January 2021 via in-depth, semi-structured interviews with nine mothers of children who had to home quarantine. Interviews were conducted face-to-face in an independent space near the participant's home or workplace (n=5) or via online platforms or telephone (n=4). The data were analyzed using thematic analysis through several iterative team meetings. Results: Thematic analysis revealed the following four themes: "Unable to be relieved due to uncertain situations surrounding me," "Blame and hurt toward me, others, and one another," "Pulling myself together for my children in my broken daily life," and "Changes in the meaning of life amid COVID-19." Conclusion: The narratives show that mothers experienced psychosocial difficulties while caring for their children during home quarantine. It is necessary to reduce the social stigma toward individuals in home quarantine and establish policies to ensure work-family compatibility for such mothers.

• 한국위성정보통신학회논문지
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• 제12권3호
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• pp.8-14
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• 2017

4G 이동통신에서는 본격적으로 데이터 중심의 이동통신 서비스를 제공하기 시작했다. 이에 따라 최근 무선 트래픽에서 인터넷, 동영상을 포함한 멀티미디어 등의 서비스가 주된 콘텐츠로 자리 잡게 되었다. 이런 서비스 이용 패턴 변화에 대응하기 위해 현재 더 빠른 전송 속도를 가진 5G 이동통신에 대한 연구가 활발히 이루어지고 있다. 5G 이동통신은 기존 단말과의 호환성을 위해 4G를 기반으로 구성될 것으로 예상된다. 따라서 본 논문의 시뮬레이션 또한 4G를 기반으로 구성하였으며 시스템의 성능을 높이기 위해 Max throughput 스케줄링 알고리즘을 기반으로 새로운 사용자 스케줄링 기법을 제안한다. 본 논문은 기존의 사용자 스케줄링 알고리즘과 제안한 사용자 스케줄링 알고리즘을 비교하기 위해 주파수 효율과 공정성을 도출한다. 시뮬레이션 결과 모든 상황에서 Max throughput에 비해 향상된 성능을 보였다. 본 논문이 5G 이동통신 기술의 시스템 성능향상을 위한 연구의 참고자료로서 활용되며, 현재도 진행 중인 표준화 작업에 대해 일부 도움이 되기를 기대한다.

• 대한기계학회논문집A
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• 제41권11호
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• pp.1109-1117
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• 2017

PLC 시스템은 자체 모듈에 의한 부분적 확장성을 지원하고 있지만, 확장을 위한 비용이 크고, 센서 및 기타 제어기들과의 언어 호환성 또한 문제가 되고 있다. 본 논문에서는 빠르게 변화하는 기술에 대처하기 위해 텍사스 인스트루먼트 사의 DSP(디지털 시그널 프로세서)를 이용하여 PLC를 대체 및 보조할 수 있는 시스템을 제안한다. 이 시스템은 기존 PLC의 기능을 통합적으로 구현하며, 범용으로 쓰이는 PLC 에 비해 속도가 빠르고, 약 50% 이상의 비용 절감이 가능하다. 또한, 모듈 형태의 24V의 범용 디지털 I/O핀을 구성함으로써 선택적으로 입력과 출력의 부분적 확장을 용이하게 하였다. 일반적 산업 장비의 제어를 위해 널리 사용되고 있는 모드버스 통신을 RS-485 인터페이스를 기반으로 DSP에서 구현함으로써, 장비 간 다대다 통신을 할 수 있도록 하였다.

• Korea-Australia Rheology Journal
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• 제19권3호
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• pp.125-131
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• 2007

Biodegradable polymeric blends are expected to be widely used by industry due to their environmental friendliness and comparable mechanical and thermal properties. Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) are such biodegradable polymers which aim to replace commodity polymers in future applications. Since cost and brittleness of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. In this study, blends of PLA and PBS with various compositions were prepared by using a laboratory-scale twin-screw extruder at $180^{\circ}C$. Morphological, thermal, rheological and mechanical properties were investigated on the samples obtained by compression molding to explore suitability of these compositions for packaging applications. Morphology of the blends was investigated by scanning electron microscopy (SEM). Morphology showed a clear phase difference trend depending on blend composition. Modulated differential scanning calorimetry (MDSC) thermograms of the blends indicated that the glass transition temperature ($T_g$) of PLA did not change much with the addition of PBS, but analysis showed that for PLA/PBS blend of up to 80/20 composition there is partial miscibility between the two polymers. The tensile strength and modulus were measured by the Instron Universal Testing Machine. Tensile strength, modulus and percentage (%) elongation at break of the blends decreased with PBS content. However, tensile strength and modulus values of PLA/PBS blend for up to 80/20 composition nearly follow the mixing rule. Rheological results also show miscibility between the two polymers for PBS composition less than 20% by weight. PBS reduced the brittleness of PLA, thus making it a contender to replace plastics for packaging applications. This work found a partial miscibility between PBS and PLA by investigating thermal, mechanical and morphological properties.

• 한국분말재료학회지
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• 제17권2호
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• pp.148-153
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• 2010

Thermal barrier systems have been widely investigated over the past decades, in order to enhance reliability and efficiency of gas turbines at higher temperatures. Yttria-stabilized zirconia (YSZ) is one of the most leading materials as the thermal barriers due to its low thermal conductivity, thermodynamic stability, and thermal compatibility with metal substrates. In this work, rare-earth oxides with pyrochlore phases for thermal barrier systems were investigated. Pyrochlore phases were successfully formed via solid-state reactions started from rare-earth oxide powders. For the heat-treated samples, thermo-physical properties were examined. These rare-oxide oxides showed thermal expansion of $9{\sim}12{\times}10^{-6}/K$ and thermal conductivity of 1.2~2.4 W/mK, which is comparable with the thermal properties of YSZ.

• 한국화재소방학회논문지
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• 제34권3호
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• pp.58-66
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• 2020

주택의 경우에는 소방법에서 제외 대상으로 되어 있어 화재가 발생하더라도 초기 소화에 골든타임을 놓쳐 대부분 인명사고로 이어지고 있다. 이처럼 주택에서 화재와 사망자가 많이 발생하고 있어 소방법을 개정하여 정부에서는 2017년부터 단독 주택에도 소화기를 의무적으로 비치하도록 하였다. 소방청 2018년 주택용 기초 소방시설 설치 실태조사 자료에 의하면 전체 비치율이 34.8%에 불과하다. 소화기는 화재 시에는 꼭 필요한 기구이지만 가정집에서는 기피 대상으로 생각하고 있다. 투박하고 빨간 색상으로 되어 있어 집안 분위기와 어울리지 않기 때문이다. 이제 소화기도 평상시에는 장식품과 팬시용품처럼 집안에 비치해 두다가 화재가 발생하면 화재를 진압할 수 있도록 심플하면서도 디자인이 다양한 소화기가 있어야 한다. 집안 어디에 두어도 장식물처럼 어울릴 수 있는 제품이라면 소비자들의 구매력을 향상시킬 수 있는 동기부여가 될 수 있다. 이제는 다양한 디자인으로 심플한 소화기가 개발되도록 관련업체의 디자인 개발이 실질적으로 이루어져 상품화를 기대한다.

• 가족자원경영과 정책
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• 제19권4호
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• pp.71-94
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• 2015

The purpose of this study is to propose measures for social work practice to enhance the happiness of middle-aged married men and women by identifying the effects of family stress and social support resources (formal and informal support resources) on marital satisfaction among mid-life married couples. Subjects were selected through purposive sampling among married men and women aged between 40 and 59 and living in Seoul City and Gyeonggi province. The study results are follows. First, the average score of family stress was 3.06 points (SD=.56), slightly higher than the median value of 3 points. Of all subscales of family stress, the subjects experienced the most stress from family relationships, followed by financial problems, health and loss of families, and work-family compatibility. In regard to social support resources, the mean value of all social support resources categories was greater than the median. Among the subscales, informal support (family support and support from other people) was found to be higher than formal support. The level of marital satisfaction was higher than the median, and the score was 3.21 points (SD=.78). Second, in order to explore differences in marital satisfaction according to family stress and social support, differences in marital satisfaction were analyzed by grouping subjects who scored high, middle, and low levels of marital satisfaction. According to the results, marital satisfaction was statistically significantly higher in the group that experienced less family stress (F=6.25, p<.01). With respect to social support, marital satisfaction was statistically significantly higher in the group that received high social support (F=29.68, p<.001). Third, according to the analysis of factors affecting marital satisfaction in middle-aged married men and women, subjective economic status, family relationship stress, economic stress, and family support showed statistical significance. The higher the subjective economic status and the lower the family relationship stress and economic stress levels, the higher the marital satisfaction among middle-aged married men and women. In addition, the greater the family support, the higher the marital satisfaction. The results of this study underscore the need to improve family relationships in middle-aged married couples and to distribute family life education programs that can strengthen family support resources. For example, family relationship enhancement programs are currently performed, including "Family School for Middle-Aged Baby Boomers" and others as part of the Healthy Family Support Work regarding the promotion of marital satisfaction of middle-aged couples. In addition, continuing effort is warranted to include content on strengthening family support resources, maximizing the effectiveness of programs, and promoting service accessibility.

• 재활복지공학회논문지
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• 제9권3호
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• pp.195-201
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• 2015

본 연구에서 언제어디서든 학습이 가능한 u-Learning 접근방법은 웹과 모바일기기를 상호호환 가능한 동시에, 안드로이드와 Mac OS, PC 등 모든 모바일 기기에서 호환이 용이하도록 HTML5을 이용하여 청각장애인의 IT 교육 콘텐츠(JSP, Oracle)를 개발하였다. 본 연구결과는 다음과 같다. 첫째, 대부분의 온라인 컴퓨터 교육과정에서 다양한 모바일기기를 지원하고 있지만, 대부분이 플래시기반으로 제작된 콘텐츠라 각각의 모바일기기에서 호환되지 않는 문제점이 있었다. HTML5를 활용하여 개발된 콘텐츠에서 웹과 모바일기기를 상호호환이 가능하였다. 둘째, 개발된 콘텐츠를 대상으로 FLASH와 HTML5 콘텐츠 제작 도구들의 장단점을 각각 비교해 볼 수 있었으며, HTML5를 활용하여 다양한 이벤트 기능을 구현할 수 있는 추가적인 연구가 필요하였다. 셋째, 청각 장애인의 u-Learning 설계 지침과 모바일 애플리케이션 접근성 지침에 따라 웹과 모바일 기기의 접근할 수 있는 설계 전략들을 비교해 볼 수 있었다. 하지만, 모바일 애플리케이션 접근성 지침의 경우 장애유형에 따라 교육 접근성을 높일 수 있는 설계지침에 관한 추가적인 연구가 필요하였다.