• 교육시설 논문지
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• 제24권2호
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• pp.11-18
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• 2017

Most primary and secondary schools in Korea provide school meals to students. After the implementation of the manual in the development of foodservice facilities within schools in the Seoul metropolitan area, this study had been instituted towards the improvement on the design of the school. Through the investigation of the use of school foodservice facilities and the establishment of putting the designer's design to the users into effect, primary and secondary schools have been observed in the study to conclude the following research: Spatial Configuration and Usage Characteristics within Elementary, Middle, and High school.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1489-1503
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• 2018

Spectrum reuse has attracted much concern of researchers and scientists, however, the dynamic spectrum access is challenging, since an individual secondary user usually just has limited sensing abilities. One key insight is that spectrum usage forecasting among secondary users, this inspiration enables users to obtain more informed spectrum opportunities. Therefore, spectrum usage forecasting is vital to cognitive radio networks (CRNs). With this insight, a spectrum usage forecasting model for the occurrence of primary users prediction is derived in this paper. The proposed model is based on auto regressive enhanced primary user emergence reasoning (AR-PUER), which combines linear prediction and primary user emergence reasoning. Historical samples are selected to train the spectrum usage forecasting model in order to capture the current distinction pattern of primary users. The proposed scheme does not require the knowledge of signal or of noise power. To verify the performance of proposed spectrum usage forecasting model, we apply it to the data during the past two months, and then compare it with some other sensing techniques. The simulation results demonstrate that the spectrum usage forecasting model is effective and generates the most accurate prediction of primary users occasion in several cases.

• 한국인터넷방송통신학회논문지
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• 제10권6호
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• pp.9-15
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• 2010

인지전파 기술은 지역과 시간에 따라 일시적으로 사용하지 않는 주파수 대역을 자동으로 인지하고 찾아서 환경에 맞게 통신방식, 주파수 대역폭 등을 능동적으로 판단하여 통신함으로서 한정적인 주파수 자원을 효율적으로 사용하고자 하는 기술이다. 본 논문에서는 오검출과 오경보의 불완전한 센싱 환경하의 인지 전파망에서 주사용자나 부사용자의 세션 큐가 스펙트럼 사용효율에 어떤 영향을 미치는 지를 연속시간 마르코프 체인 분석을 통하여 정량적으로 규명하였다. 큐가 있을 경우 주 사용자는 최대 18% 까지, 부 사용자는 최대 50% 까지 스펙트럼 사용 효율을 높일 수 있었다.

• East Asian mathematical journal
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• 제29권1호
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• pp.101-107
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• 2013

We consider a cognitive network with a primary and a secondary channel. Primary users have higher priority on the usage of the primary channel, and secondary users are allowed to opportunistically access the primary channel at times when the channel is not occupied by primary users. The secondary channel is dedicated only to secondary users. An analytical model is presented to obtain the performance of an opportunistic spectrum access using both the primary and secondary channels, and is validated by simulations.

• 한국통신학회논문지
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• 제34권8C호
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• pp.731-741
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• 2009

최근 셀 커버리지 증대와 음영지역 및 핫스팟(hot spot) 지역의 서비스 공급을 위해 추가적인 기지국 설치를 하지 않고 중계기를 활용하고 있다. 중계기는 기지국과 지형적으로 떨어져 있기 때문에 중계기와 기지국이 서로 다른 스크램블 코드를 사용할 때, 코드간 간섭이 줄어들 수 있다. 본 논문은 이와 같은 사실을 이용하여 중계기를 활용한 primary-secondary 스크램블 코드 활용 방안을 연구한다.. 이를 위해서 다섯 가지의 시나리오를 제시하고, 각 시나리오 별 성능을 시스템 레벨 시뮬레이션을 통해 비교한다. 이에 더하여, secondary 스크램블 코드의 미치는 간섭을 줄이고, 아웃티지(outage) 성능을 향상시키기 위해서 기지국-중계기간 스위칭(switching) 기법과 primary-secondary 스크램블 코드간 리플레이싱(replacing) 기법을 제안한다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.401-407
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• 2022

Central heating, ventilation and air conditioning (HVAC) is one of the largest consumers of energy in the residential sector. This project explores the use of multiple HVAC units and/or Zoning in a single residence to reduce energy loads. The energy consumption data of a detached single-family home using two HVAC units, one primary for the main house and a secondary HVAC for a casita, was collected for the same month for two consecutive years, along with details related to the outdoor temperature and the square footage being air-conditioned by each HVAC. A regression algorithm was trained using the above details to find the relation between the parameters. Next, based on the occupancy and usage patterns, the HVAC was redesigned assuming more area under the secondary HVAC unit. The trained algorithm was then used to make energy usage predictions for the revised primary HVAC area, with the assumption that the secondary HVAC unit was turned off. The results were compared with existing energy usage data. It was determined that there were significant energy savings in the second scenario. It is expected that this study and its findings will help future research projects explore more ideas as alternatives to central HVAC, in improving the economic viability of existing options, and in developing a savings calculation tool that will help consumers make informed decisions on their best alternatives to central HVAC.

• Human Ecology Research
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• 제56권6호
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• pp.493-506
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• 2018

This study analyzes factors that determine the usage of digital information by senior consumers in the mobile environment. Senior consumers are alienated from digital information in South Korea; therefore, there have been increasing attempts to resolve this digital divide and reduce the digital information usage gap between young adults and senior consumers. The study used panel data from the National Information Society Agency (2017); there were 1,463 participants, aged 50-79 years. SPSS 19.0 was used to conduct the statistical analyses for frequency, factor analysis, Cronbach' ${\alpha}$ analysis, descriptive analysis and hierarchical multiple-regression analysis. The results are as follows. First, negative attitude toward information society negatively influenced the mobile digital information usage in diversity context. Second, average monthly income, degree of digital device usage motivation, positive attitude toward digital device usage, digital literacy of PC & Mobile, and family support positively influenced the mobile digital information usage in diversity context. Third, negative attitudes toward information society negatively influenced the mobile digital information usage in quality context. Forth, average monthly income, degree of digital device usage motivation, positive attitude toward digital device usage, digital literacy of PC & mobile, and family support positively influenced the mobile digital information usage in quality context. The study results can help further understand mobile usage behaviors among senior citizens and the implications on their quality of life in the digital information era.

• Journal of Ecology and Environment
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• 제43권2호
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• pp.202-211
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• 2019

Oceanic islands are biologically important for their unique assemblages of species and high levels of endemism and are sensitive to environmental change because of their isolation and small species source pools. Habitat destruction caused by human landscape development is generally accepted as the main cause of extinction on islands, with exotic species invasion a secondary cause of extinction, especially on tropical islands. However, secondary impacts of human development (e.g., general degradation through resource use and exotic species introduction) are understudied on temperate islands. To determine secondary impacts of human development on the understory vegetation community, 90 field sites on Ulleung Island, South Korea, were sampled during the summer of 2016. Understory vegetation was chosen as it is a proxy for ecosystem health. Diversity and percent cover of introduced, native, and endemic species were tested against proximity to developed areas and trail usage using a model selection approach. Diversity was also tested against percent cover of three naturalized species commonly found in survey plots. The main finding was that distance to development, distance to town, and trail usage have limited negative impacts on the understory vegetation community within best-supported models predicting native and introduced cover and diversity. However, endemic species cover was significantly lower on high usage trails. While there are no apparent locally invasive plant species on the island at the time of this study, percent cover of Robinia pseudoacacia, a naturalized tree species, negatively correlated with plot diversity. These findings indicate that forests on Ulleung Island are not experiencing a noticeable invasion of understory vegetation, and conservation efforts can be best spent preventing future invasions.

• 한국환경교육학회지:환경교육
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• 제17권2호
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• pp.60-78
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• 2004

A survey performed on property of water usage, a recognition and stand on water, and awareness of practice related to water saving among primary and secondary teachers in Daegu metropolitan city leads to the following result. First, regarding the actual condition of water usage, boiled tap water was most preferred, followed by purified tap water, mineral water, and water from a mineral spring respectively. Second, the result of a survey regarding a recognition and stand on water presents that the quality of purified water and mineral water is generally trusted, not including tap water. A majority of teachers barely had any ideas on the process of tap water supplies and sewage disposal system. Third, another survey was performed to determine whether there's a gender difference on a general recognition of and stand on water usage, actual practice of water saving and love for water. As a result, 7 out of 25 questions showed the difference of significance by p<.05. As for tap water service and sewage disposal system, there were differences on 5 out of 6 questions, indicating that male teachers are more knowledgable than their female counterparts. Fourth, the result of the research about the recognition and attitudes about water and water saving of the teachers who were categorized by the age group showed that 14 questions of the 25 questions had differences in p<.05 level. Teachers in their twenties and thirties had less interest than those in their forties and fifties.

• 한국콘텐츠학회논문지
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• 제17권5호
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• pp.262-272
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• 2017

본 연구에서는 종래 애니메이션 관련 라이선싱에서 주로 다루어왔던 1차적 라이선스 요소인 캐릭터가 아니라 애니메이션의 배경 등 2차 이미지를 활용, 브랜드의 시각적 확장을 달성한 사례를 중심으로 분석한다. 2차 이미지는 내러티브가 발생되는 환경적 요인을 제공하며, 시대적 지리적 속성이 캐릭터로 하여금 사건을 발생시킬 수 있는 중요한 단서를 제공하기도 한다. 본 연구는 애니메이션 원작에서 라이선싱 프로세스에 활용될 수 있는 요소를 1차 활용과 2차 활용으로 구분하여 그 범위를 규정하고, 라이선싱을 통한 실제 협업사례를 통해 구현된 2차 활용의 표현 요소와 실제 제품 간의 시각적 관계를 고찰한다. 구체적 사례로서 디즈니사의 '정글북'과 겐조, '이상한 나라의 엘리스'와 마크 바이 마크 제이콥스의 협업을 선정하여, 두 브랜드에서 드러난 2차 활용을 원작과 비교하여 분석하였다. 연구결과 두 사례에서 2차 이미지를 통한 시각정보를 확장시키면서 아이덴티티를 선명하게 드러냄을 알 수 있었다. 2차 이미지 활용 사례를 통해 향후 가능성을 확인 할 수 있었으며, 지속적으로 발생될 유사 사례와 라이선스의 범위가 확장되는 현 시점에서 새로운 라이선싱 프로세스가 요구됨을 알 수 있었다.