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        검색결과 1,269

        181.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        어선과 같은 소형선박의 충돌사고는 큰 인명피해를 초래한다. 본 연구 이전에 선행된 연구에서는 충돌위험을 판단하고 경보를 발생시키는 소형선박 충돌예방 알고리즘을 개발하였다. 하지만 충돌경보와 같이 안전을 위해 제공되는 서비스는 위험을 예방할 뿐 아니라 이용자의 만족도 또한 어느 정도 수반되어야 효과적으로 기능할 수 있다. 본 연구에서는 소형선박 충돌예방 알고리즘의 실용성 향상을 위해 알고리즘을 개선하고, 알고리즘을 실제로 적용하여 개선결과 및 효과를 확인하고자 하였다. 충돌경보 서비스를 사용한 소형선박 운항자들을 대상으로 설문조사를 수행한 결과, 충돌경보의 정확도 향상과 경보 횟수 및 음량에 대한 사용자들의 요구사항이 확인되었다. 이에 따라 본 연구에서는 사용자 만족도 향상을 위해 알고리즘을 개선하였으며 실제 해상환경에서 개선된 알고리즘을 적용한 실선실험 을 수행하였다. 그 결과 개선 전보다 경보 발생 빈도가 감소하였지만, 위험한 상황에서는 경보가 비교적 꾸준히 발생하였으며, 충돌경보의 정확성과 실용성이 향상된 것으로 분석되었다. 추후에는 개선된 알고리즘의 적정성에 대한 근거자료를 마련하여 알고리즘의 실용성과 신뢰성을 확보한다면 소형선박 충돌사고 예방에 효과적으로 기여할 수 있을 것이다.
        19,400원
        182.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study set up the estimates of leakage management efficiency evaluation and leakage management goal that could be used in local water distribution networks efficiency business and modernization business. The data were analyzed using data envelopment analysis and multiple regression analysis. To this end, with leakage management input indices concerning leakage reduction activities (e.g., aged pipe replacement, water meter replacement, leakage restoration, and leakage detection) and leakage management calculation indices (e.g., the increase of revenue water ratio and the reduction of leakage ratio), the data on 22 K-water consignment local water supply systems were analyzed for the years from 2004 through 2018. Using the results of efficiency analysis by data envelopment analysis, the other DMUs (Decision Making Unit) benchmarked the DMU with the highest efficiency to maximize the leakage management efficiency for all DMUs. Through this, leakage management goal estimates were drawn with the input indices of four leakage reduction activities and calculation indices of the increase of revenue water ratio and the reduction of leakage ratio by multiple regression analysis for each group based on the revenue water ratio and leakage ratio. The correlation coefficients of the leakage management goal estimate for the criteria for the revenue water ratio amounted to 0.553 and 0.771. The correlation coefficients of the leakage management goal estimate for the criteria for leakage ratio were 0.397 and 0.865. Accordingly, we estimated the quantity and priority of four leakage reduction activities for the target leakage ratio and revenue water ratio.
        4,500원
        183.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Being an island has often proved a health benefit in dealing with the COVID-19 pandemic. Indeed, after a year of the pandemic, virtually the only COVID-free countries are island states and territories. While both Australia and South Korea have fared well by global standards, their island provinces, Jeju and Tasmania done even better. The small island states of the South Pacific region leveraged their insularity by swiftly closing borders, tough quarantine, social distancing and public health measures when a pandemic was declared. Their marine moat contributed significantly to health security for these islands but at great cost to their fragile economies especially those with some dependence on tourism. Vaccines promise the opportunity to reopen borders to international commerce and traffic. However, the transition out of the pandemic will less swift and less secure than the initial dramatic first response. The apparent inevitability of COVID becoming an endemic disease will require ongoing public health measures as well as political decisions at the level of individual countries as when decide their pandemic measures can be relaxed. Travel bubbles are touted as a likely transitional stage for the global recovery but these have proved more aspirational than practical thus far. Post-COVID financial revitalisation will even more challenging for small island states. It is here that both Jeju and Tasmania can assist their national government in meeting the needs of the Pacific’s small island states. They have relevant island-adapted human and physical technologies that, if recognised and mobilised, could make appropriate niche recovery aid more effective.
        3,000원
        184.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is little information on the nutrient intake according to the city size and small town in Korean elderly. This study analyzed the nutritional consumption of older people in metropolitan, middle and small cities, and rural areas according to four income levels. The recent data from the 2016~2018 Korean National Health and Nutrition Survey, Centers for Disease Control and Prevention were used. The final analysis included 4,325 individuals (Male: 1,856, Female: 2,469) over 65 years old. Multivariable regression with a complex sample design was conducted to compare the nutrient intake among the groups. In a comparison within regions, the nutrition status of the elderly in small towns was more vulnerable than metropolitan and middle & small cities. The energy intakes were similar between the groups. The carbohydrate intake of middle & small cities was significantly higher than the other regions. The intake of other nutrients in metropolitan and middle & small cities appeared to be higher than in rural areas. The number of nutrients with statistical significance between low and high-income levels were 19 in metropolitan, 11 in middle & small cities, and 5 in rural areas. Each contribution of carbohydrate, fat, and protein to the total energy intake was lower in the low-income level than the high-income level in metropolitan and middle & small cities. On the other hand, in rural areas, only the contribution of protein to energy intake was lower in the low-income level than the high-income level. Cities with higher levels of urbanization had more severe nutritional inequality in relation to the income level. There was also nutritional inequality present in rural areas but it was to a lesser extent. Moreover, the generally low level of nutrient intake was problematic in rural areas. These findings could be used as fundamental evidence for developing community nutritional policies for the elderly.
        4,200원
        185.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구기관의 협력 네트워크 구조 및 특징은 기관의 학문적 성과에 영향을 미친 다. 특히 한국의 정부출연연구기관은 선도적인 국가 연구개발 수행 주체로서 효율적인 협력 체제를 구축해야 할 필요가 있다. 본 연구는 효율적인 네트워크 구조로 논의되어 온 좁은 세상 구조와 노드간 특징을 나타내는 중심성을 한국 과학기술계 정부출연연구기관 협력 네트워크에 적용하였다. 2010년∼ 2019년 과학기술계 정부출연연구기관의 논문 데이터를 바탕으로 좁은 세상 구조적 특징 및 중심성과 논문 성과 간 관계를 네트워크 분석과 Feasible GLS 회귀모형을 이용하여 분석하였다. 그 결과, 정부출연연구기관 협력 네트워크는 좁은 세상 구조를 취할수록 학문적 성과 에 유의미한 양의 성과를 거둘 수 있는 것으로 나타났다. 또한, 직접적인 연결 정도를 나타내는 중심성은 양의 유의성을 보였으나, 중개자 정도를 나타내는 중심성은 유의하지 않거나 음 으로 유의했다. 교류 협력하는 기관의 수가 많을수록 논문 성과가 높았으며, 협력의 중심지 역할을 하는 기관과 협력 관계인 기관의 성과가 높다. 또한, 정부출연연구기관의 협력 네트워크가 좁은 세상의 특성을 강하게 가질수록 연구 성과 창출에 효과적이라는 것을 규명하였다. 본 연구는 기존에 효율적인 네트워크 구조로서 논의되던 좁은 세상 구조와 중심성을 정부출연연구기관 협력 네트워크에 적용하고 성과와의 관계를 실증 분석할 뿐 아니라 정부출연연구기관 간 연 구개발 협력관련 정책 및 전략 수립에 시사점을 제시한다.
        8,300원
        186.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand the role of small heat shock protein (sHSPs) in rice plant response to various stresses such as the heat and oxidative stresses, a cDNA encoding a 24.1 kDa mitochondrial small HSP (Oshsp24.1) was isolated from rice by rapid amplification of cDNA ends (RACE) PCR. The deduced amino acid sequence shows very high similarity with other plant small HSPs. DNA gel blot analysis suggests that the rice genome contains more than one copy of Oshsp24.1. High level of expression of Oshsp24.1 transcript was observed in rice seedlings in response to heat, methyl viologen, hydrogen peroxide, ozone, salt and heavy metal stresses. Recombinant OsHSP24.1 protein was produced in E. coli cells for biochemical assay. The protein formed oligomeric complex when incubated with Sulfo-EGS (ethylene glycol bis (succinimidyl succinate)). Our results shows that Oshsp24.1 has an important role in abiotic stress response and have potential for developing stress-tolerant plants.
        4,000원
        187.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 외부형태적으로 매우 비슷한 참조기 (Larimichthys polyactis) 와 부세 (L. crocea)의 두 종 간 구분을 위해 계측형질 분석을 포함한 몇가지 기법들을 수행하였다. 총 48개의 계측형질 중 4개의 유의한 차이를 보이는 계측형질이 파악되었으며 (p<0.05) classical dimension에서는 유의한 차이를 보이는 계측형질은 없었다 (p>0.05). 오히려, 2가지의 truss dimension (Insertion of dorsal fin base - origin of pectoral fin base와 Origin of anal fin base - origin of pectoral fin base)와 2가지의 head part dimension (Most anterior extension of the head - above of eye와 Above of eye - posterior aspect of operculum)에서는 유의한 차이가 나타났다 (p<0.05). 하지만, 이러한 4가지 계측형질 중 head part dimension의 Above of eye - posterior aspect of operculum의 계측형질을 제외한 나머지 3가지 계측형질들에서 부세가 참조기에 비해 더 큰 수치를 나타내었다 (p<0.05). X-ray 분석 결과 curved vertebral column에서 부세는 45.1±2.34° 로 참조기의 38.4±1.82°에 비해 8.4% 더 큰 수치를 나타내었다 (p<0.05). 머리부위의 표피를 제거한 후의 유상돌기 는 두 종에 모두 존재하여 일반적으로 참조기에서만 유상 돌기가 존재한다고 알려진 바와는 달리, 유상돌기는 두 종을 구분하기 위한 형질로 볼 수 없었다. 본 연구 결과는 참조기와 부세에서 일부 외부 체형에 의해 명확히 구분 가능함을 시사한다.
        4,200원
        195.
        2020.11 구독 인증기관 무료, 개인회원 유료
        Paid search advertising is the most popular online advertising format, and many large firms allocate a considerable amount of their advertising budget to it. In contrast, small and medium-sized firms have a limited advertising budget that potentially forces them to experience the ineffectiveness of paid search advertising. In this study, we identify the various paid search advertising strategies that even small and medium-sized firms can implement and examine the effect of the different advertising strategies on the number of clicks as a primary advertising performance measure. Using the data regarding keyword advertising from a search engine, we find that advertisers can increase the number of clicks not only by increasing their bids, but also by optimal keyword selection, targeting, and active advertisement management. Our findings provide a practical insight that there are many other advertising strategies for the managers to utilize beyond budget efficiently.
        4,000원
        196.
        2020.11 구독 인증기관 무료, 개인회원 유료
        This study enrolled enterprise business owners/managers in the U.S. as the subjects to investigate the relationship among four factors: personal motivation, the social expectation of stakeholders, business performance, and their CSR toward the local community. The research results showed that: (1) small enterprise’s perceived expectation from stakeholders has a positive effect on their decision to engage in CSR toward community; (2) their perception of business performance has a positive effect on their decision to engage in CSR toward the community. Based on these research results, public policymakers or relevant units are advised to further achieve the goal of nurturing a flourishing community by increasing awareness of stakeholder’s expectations for small enterprise’s CSR commitment. Also, it is clearly pronounced in this study that regardless of their personal motivation to support the local community, unless financially successful, small businesses are less likely to engage in CSR toward the local community. This result makes a good sense that having a successful business operation is a necessary condition for small enterprises to pay attention to a higher-level value such as CSR toward the local community.
        4,000원
        198.
        2020.11 구독 인증기관·개인회원 무료
        The small tea growers (STGs) constitute a significant part of the tea industries in several tea producing countries in the world. STGs constitute 70 percent of the tea cultivation by area and 60 percent of the total tea production by volume. However, low profitability, limited marketing options, inefficient supply chain, and dependency on the large tea estates for processing has emerged as a serious threat to the sustainability of the STGs. Mostly, the STG’s role in the tea supply chain is confined merely to the cultivation of the tea leaves. In India too, the STGs are confronted with similar challenges. India is the second-largest tea producer in the world with about 50 percent of the total tea production coming from the STGs. Notably, considering the economic and environmental benefits, some of the STGs have taken to organic cultivation of tea. Further, some of them who adopted organic cultivation also took to processing and marketing of made tea like hand-made green tea, black tea, and other specialty products by themselves. This study seeks to understand and analyze the role of organic cultivation in providing market linkages and the development of value chain(s) for the STGs. The study was conducted in the state of Assam, which is recognized worldwide for the presence of one of the oldest and the largest tea industries. It used a qualitative value chain approach to analyze the current situation of the STGs involved in the production of organic tea. The study mostly relied on primary data collected from the various actors of the emerging tea value chain through a semi-structured interview schedule, in-depth interviews, and focused group discussions. The processing and marketing of tea by the organic STGs in Assam has indeed led to the development of tea value chain(s) for the STGs. Adoption of sustainable agriculture systems like organic cultivation has opened up new opportunities for the STGs to earn from tea processing and marketing by themselves. Although such developments are in a very initial stage, understandings from the present scenario add to the literature on the development of value chain and market linkages for the smallholders in the tea sector with implications for other agricultural sectors as well. Encouraging the STGs to produce orthodox tea products, especially green and black tea varieties, in larger quantity by mobilizing them for collective actions is likely to locate them in the global tea value chain. The study suggests such suitable policy measures to bring about transformations in the tea sub-sector. Appropriate institutional changes to develop sustainable tea value chain(s) controlled by the STGs would be the key to impart overall sustainability to the industry. Such developments are likely to help the tea industry in Assam and other tea producing regions to meet the changing consumer aspirations and sustain global competition.
        199.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 시설 내 소형 수박 재배 시 관수개시점에 따른 토양수분 함량별 생육, 수량 및 생리적 반응 특성의 차이를 구명하고 소형 수박 생산에 유리한 관수조건을 구명하고자 수행하였다. 토양수분 센서를 이용하여 정식 후 14일부터 수확 7 ~ 10일 전까지 관수개시점별 5처리(-10, -20, -30, -40, 50 kPa)를 두어 관수하였다. 토양수분 함량이 가장 낮은 개시점-50 kPa 처리에서 전반적인 지상부 생육특성은 저조하였으나, 근장 및 뿌리 건물율은 증가하였다. 광합성률, 기공전도도 및 증산율 비교 시, 관수개시점-50 kPa 처리에서 가장 낮았고, -20 kPa ~ -40 kPa 처리 시 광합 성률은 높게 조사되었다. 착과율 및 총 상품수량은 -30 kPa 및 -40 kPa 처리에서 각각 84.7 ~ 85.5%, 5,144 ~ 5,305 kg/10a으로 유의하게 증가하였다. 식물체의 외부환경 관련 스트레스 지표 물질로 알려진 프롤린, ABA, 총 페놀 및 시트룰린의 함량은 토양수분 함량이 낮아질수록 증가하였으며, 특히 관수개시점-50 kPa 처리에서 가장 높게 조사 되었다. 따라서 이와 같은 결과를 종합해 볼 때, 시설 내 안정적인 소형 수박 생산을 위하여 관수개시점을 -30 kPa ~ -40 kPa 수준으로 조정하여 토양수분 함량을 조절하는 것이 수박 생육 향상 및 상품수량 증대에 가장 유리한 것으로 판단되었다.
        4,200원
        200.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : A pilot experimental study on the formation of fine particulate matter through photochemical reactions using precursor gas species (volatile organic compounds (VOCs), NH3, SO2, and NOx) was conducted to evaluate the large-scale environment chamber for investigating the pathway of aerosol formation and the subsequent assessment techniques used for reducing fine particulate matter. Two small-scale environment chambers (one experimental group and one control group), each with a width, depth, and height of 3 m, 2 m, and 2.3 m, respectively, were constructed using ethylene tetrafluoroethylene (ETFE) films. METHODS : The initial conditions of the fine particles and precursor gases (NOx and VOCs) for the small-scale environment chamber were set up by injecting diesel vehicle exhaust. NH3 and H2O2 were added to the small-scale environment chamber for the photochemical reaction to form organic and inorganic aerosols. The gas phase of the VOCs and the chemical compositions of aerosols were investigated using a proton transfer reaction time-of-flight mass spectrometer and the aerodyne high-resolution time-of-flight aerosol mass spectrometer at 1 and 10 s time resolutions, respectively. Gas phases of NO and NO2 were measured using Serinus 40 NOx at a 20 s time resolution. RESULTS : The small-scale environment chambers built using ETFE films were proved to supply sufficient natural sunlight for the photochemical reaction in the environment chambers at an average of approximately 89% natural sunlight transmission at 300–1000 nm. When the intermediates of NH3 and H2O2 for the atmospheric chemical reaction were injected for the initial condition of the small-scale environment chamber, nitrate and ammonium in the experimental group increased to 4747% and 1837%, respectively, compared to the initial concentrations (5.4 μg/m3 of nitrate and 5.2 μg/m3 of ammonium), indicating the formation of secondary inorganic aerosols of ammonium nitrate (NH4NO3). This implies that it is necessary to inject intermediates (NH3 and H2O2) for the formation of fine particulate matter when simulating the atmospheric photochemical reaction for assessing the environment chamber. CONCLUSIONS : This study has shown that small-scale environment chambers can simulate the atmospheric photochemical reaction for the reduction of fine particulate matter and the formation of the aerosol pathway. The results of this study can be applied to prevent time and economic losses that may be incurred in a full-scale environment chamber.
        4,200원