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        검색결과 2,366

        401.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        여수와 제주도 사이 해역에 출현한 수표성 동물플랑크톤의 군집 분포와 환경요인 간의 관계를 파악하기 위해 2017년 9월 총 14개 정점에서 뉴스톤 네트를 이용하여 선박 측면에서 예인 및 채집하였다. 동물플랑크톤은 총 81개 분류군으로 요각류가 최우점하였다. 동물플랑크톤 출현 개체수를 기반으로 연안수의 영향을 받는 해역, 연안수와 외 해수가 만나는 해역, 외해수의 직접적 영향을 받는 해역으로 구분되었다. 본 연구에서 해역별 우점 요각류, 식성에 따른 요각류를 2개 그룹으로 구분하고 군집에 미치는 환경요 인을 분석한 결과 수온과 염분, 식물플랑크톤, 부유플라스틱과 유의미하였다 (p<0.05). 추가로 연구 해역에 출현한 치어 및 화살벌레류의 위 내용물 분석을 통해 미세플라스틱 섭식을 확인하였다. 낮은 영양단계에서 섭취한 플라스틱이 먹이사슬을 타고 올라가 높은 영양단계로 전달된 것으로 보인다. 결과적으로 우리나라 남해 서부 해역에 출현하는 동물플랑크톤 군집 특성을 볼 때 여름철 확장 범위를 달리하는 섬진강 수, 제주난류, 쓰시마난류의 영향을 받아 군집 분포가 달라지는 것으로 판단된다.
        4,800원
        402.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explored in what directions the 2017 KSL curriculum should be improved in order to be properly implemented in the field. To this end, it was analyzed according to the implementation factors, direction of action, validity, clarity, and feasibility factors, and the following improvement measures were derived: (1) From the action direction factor, it should be designed as a framework in which teachers can reconstruct the curriculum from the perspective of mutual adaptation. (2) In terms of validity, the contents of teaching and learning and language materials should be organized according to achievement standards. In addition, it is suggested that the 2017 KSL curriculum could be organized so that it can be cross-referenced with the achievement standards of this curriculum by establishing the relationship between upper or other curriculum. (3) In terms of clarity, the contents of culture and academic language proficiency must be presented in detail. In addition, it is required to specify the details of teaching and learning methods by each school level and Korean level. (4) In terms of feasibility factors, it is suggested to present an effective teaching and learning methods of this curriculum operated as a grade-free system, and to provide a curriculum manual.
        5,700원
        403.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm‘s ability to interpret seemed to be excellent.
        4,300원
        404.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study analyzed explanatory variables, such as dangerous driving behaviors, in a negative binomial regression model, using the Digital Tachograph data of commercial vehicles, to assess the factors associated with freeway accidents. METHODS : Fixed parameter and random parameter negative binomial regression models were constructed using freeway accident data of commercial vehicles from January 2007 to July 2018 on the Gyeongbu Expressway from West Ulsan Interchange to Gimcheon Junction. RESULTS : Six explanatory variables (logarithm of average annual daily traffic, sunny, rainy, and snowy weather conditions, road curvature, and driving behaviors that included sudden stops) were found to impact the occurrence of freeway accidents significantly. Two of these variables (snowy weather conditions and sudden stops among dangerous driving behaviors) were analyzed as random parameters. These variables were shown as probabilistic variables that do not have a fixed impact on traffic accidents CONCLUSIONS : The variables analyzed as random parameters should be carefully considered when the freeway operating authorities plan an improvement project for highway safety.
        4,000원
        405.
        2020.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To increase the utilization of the intelligent methodology of smart farm management, estimation modeling techniques are required to assess prior examination of crops and environment changes in realtime. A mandatory environmental factor such as CO2 is challenging to establish a reliable estimation model in time domain accounted for indoor agricultural facilities where various correlated variables are highly coupled. Thus, this study was conducted to develop an artificial neural network for reducing time complexity by using environmental information distributed in adjacent areas from a time perspective as input and output variables as CO2. The environmental factors in the smart farm were continuously measured using measuring devices that integrated sensors through experiments. Modeling 1 predicted by the mean data of the experiment period and modeling 2 predicted by the day-to-day data were constructed to predict the correlation of CO2. Modeling 2 predicted by the previous day's data learning performed better than Modeling 1 predicted by the 60-day average value. Until 30 days, most of them showed a coefficient of determination between 0.70 and 0.88, and Model 2 was about 0.05 higher. However, after 30 days, the modeling coefficients of both models showed low values below 0.50. According to the modeling approach, comparing and analyzing the values of the determinants showed that data from adjacent time zones were relatively high performance at points requiring prediction rather than a fixed neural network model.
        4,000원
        410.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to provide fundamental data on the convenience foods purchase according to the food-related lifestyle. This study was conducted on 398 Chinese international students residing in Gyeonggi area between October and December 2019. Among the total 373 survey subjects, gender was 183 male students (49.1%) and 190 female students (50.9%). This study was conducted by questionnaire method with reference to previous studies. There are significant differences in economic pursuit and taste pursuit for delivery food use, economic pursuit and taste pursuit for delivery food information, health pursuit and taste pursuit in delivery food ordering method, and economic pursuit and convenience pursuit for delivery food use (p<0.05). Delivery food usage time was significantly different in convenience pursuit, health pursuit, eating out pursuit, and taste pursuit (p<0.05), and the delivery food preference menu was significantly different in economic pursuit, health pursuit, eating out pursuit, and taste pursuit (p<0.05). The menu positive factors among satisfaction factors showed statistically significant differences in economic pursuit (β=0.188, t=3.531) and health pursuit (β=0.160, t=3.099) among food related lifestyle factors. In conclusion, this study presented the desirable direction of delivery food usage in Chinese students.
        4,000원
        411.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 포트하코트 시와 나이지리아 리버스주 오비오/아크박 지역의 인력과 기술력 부족이 농업 종합 기업 발전에 영향을 주는지 검토하고, 또한 이외 어떠한 요인이 농업 종합 기업에 영향을 미치는지 분석을 해보았다. 데이터는 두 지방 정부에서 300개의 농업기업에 대해 확보한 자료이다. 분석방법은 인구적 통계, 요인분석 및 다항로지스틱회귀분석을 이용하였다. 다항로지스틱 분석결과 유의성이 5% 이내이며, 이는 인력과 기술력 부족이 농업 종합 기업 발전에 영향을 주는 것을 의미한다. 이에 농업 종합 기업의 수익을 높이기 위해 기업 내부의 관리를 철저히 해야되고 내부 인원의 협작 및 기술능력을 강화시켜야 한다. 또한 과학기술혁신을 통해 기업의 개혁을 촉진해야 한다.
        4,000원
        412.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.
        6,000원
        413.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to provide priorities of the factors affecting the introduction of Smart Factory, This study reconstructed the factors and calculated the priorities through AHP (Analytic Hierarchy Process). The first layer of the hierarchy have 4 factors; productivity increase, brand image improve, marketing improve, cost reduction. The second layer of the hierarchy have 3 factors belong to the first layer, so the total number of second layer is 12. We divided the characteristics of enterprises into type of manager and age. The C.R. (consistency ratio) values of the respondents were found to be less than 0.1 and were judged to be a 'reasonable test'. As a result, the weights of the higher layer and the lower layer were obtained respectively, and then the weights of the higher layer and the weights of the lower layer were multiplied to obtain the total weights. Unlike previous studies that only surveyed factors that companies consider when introducing smart factory, (1) weighing and prioritizing factors were achieved. There are differences in priorities, (2) smart factory can be studied with the type of manager and firm age. When establishing policies, it is a practical implication (3) to assess its strategy not only for government officials but also for executives.
        4,000원
        414.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the first HPAI epidemics in 2003, there has been little epidemiological research on the association between HPAI epidemics and vehicle movements around poultry farms. This study examined the relationship between vehicle movements around poultry farms and the 2014/15 HPAI epidemics in the Republic of Korea using two methods: a boosted regression trees (BRT) model and logistic regression of a generalized linear model (GLM). The BRT model considers the non-linearity association between the frequency of vehicle movements around poultry farms and the HPAI outbreak status per province using a machine learning technique. In contrast, a GLM assesses the relationship based on the traditional frequentist method. Among the three types of vehicle movements (outbound, inbound, and within), only the outbound was found to be a risk factor of the 2014/15 HPAI epidemics according to both the BRT model and multivariate logistic regression of GLM. In the BRT model results, the median relative contribution of the log-transformed outbound variable was 53.68 (range: 39.99 – 67.58) in the 2014 epidemics and 49.79 (range: 33.90 – 56.38) in the 2015 epidemics. In the GLM results, the odds ratio of the log-transformed outbound variable was 1.22 for the 2014 HPAI epidemics (p < 0.001) and 2.48 for the 2015 HPAI epidemics (p < 0.001), respectively. The results indicated that intensive disinfection measures on outbound movement were needed to reduce the risk of HPAI spread. The current BRT models are suitable for risk analysis because the median area under the receiver operating characteristic curve was 0.83 (range: 0.74 – 0.91) and 0.85 (range: 0.73 – 0.87) for the 2014 and 2015 epidemics models, respectively. The Akaike information criterion scores for the multivariate logistic regression of GLM were 150.27 and 78.21 for the 2014 and 2015 epidemics models, respectively. These scores were relatively lower than those from the univariate logistic regression of GLM.
        4,000원
        415.
        2020.06 구독 인증기관 무료, 개인회원 유료
        Maritime sector has played a critical role for the growth and development of the Malaysia in facilitating global trade. Malaysia rely on the sector for the import and export of goods as around 90% of the nation trade is carried through maritime transportation. Although there are increasing in trade performance, Malaysian maritime industry is still facing a hard times to safeguard Malaysia's economic interests and to retain its competitive advantage as a leading maritime nation. Therefore, this paper aims to identify, analyses and evaluate the factors that influencing Malaysian maritime industry in remaining sustainable in global trade. In order to explain how the influencing factors affect the Malaysian maritime industry, a systematic hierarchical structure was developed. Then, by employed Analytical Hierarchy Process (AHP) technique, the priorities among various criteria was determined through the judgments of experts using a set of scales. The results of this study will assist the shipping entities to cope with those challenges and for Malaysia maritime sector to remain a key enabler of international trade.
        4,000원
        416.
        2020.06 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to identify methods for attracting more students into maritime colleges, for making sure they remain happy, satisfied with their decision and finally for enabling them to have job security. At International Maritime College Oman (IMCO), the Deck Officer program is a field of study that incorporates the ancient knowledge and techniques in navigation with the latest information and technology in the maritime industry. The industry requires officers who are well trained and capable of working as professionals on board vessels. The goal is to attract more students into the maritime industry, to ensure their achievement in future and to make sure they are happy with their choice to join the maritime industry. For the purposes of this research, a questionnaire about deck cadets’ experiences of work and life at sea, with thirty-one questions, was prepared, based on the authors’ experiences, and distributed to deck cadets studying in International Maritime College of Oman (IMCO). It was answered by sixty deck students in years two, three and four. The students were of both genders and from various countries including Oman, UAE, Saudi Arabia, Bahrain, Qatar and Egypt. The age ranges varied between eighteen to twenty-five. The main problems adversely affecting the students’ happiness and satisfaction were found to be related to loneliness and emotional insecurity at sea, resulting from inadequate opportunities for communication with family and friends, as well as uncertainty about employment prospects. Colleges need to focus more on supporting cadets’ emotional well-being. Shipping companies also need to play a greater role in reducing cadets’ uncertainty by sponsoring them, by providing guarantees of employment and by looking after them well at sea, especially by ensuring availability of cheap internet.
        4,200원
        417.
        2020.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, factors considered to be causes of promotion of densification of sintered pellets identified during phase change are reviewed. As a result, conclusions shown below are obtained for each factor. In order for MA powder to soften, a temperature of 1,000 K or higher is required. In order to confirm the temporary increase in density throughout the sintered pellet, the temperature rise due to heat during phase change was found not to have a significant effect. While examining the thermal expansion using the compressed powder, which stopped densification at a temperature below the MA powder itself, and the phase change temperature, no shrinkage phenomenon contributing to the promotion of densification is observed. The two types of powder made of Ti-silicide through heat treatment are densified only in the high temperature region of 1,000 K or more; it can be estimated that this is the effect of fine grain superplasticity. In the densification of the amorphous powder, the dependence of sintering pressure and the rate of temperature increase are shown. It is thought that the specific densification behavior identified during the phase change of the Ti-37.5 mol.%Si composition MA powder reviewed in this study is the result of the acceleration of the powder deformation by the phase change from non-equilibrium phase to equilibrium phase.
        4,000원
        418.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        변전소 구조물 내부에 설치되는 전력설비의 내진설계 시 사용되는 변수인 가속도 증폭계수는 미국, 일본과 국내의 변전소 내진설 계기준에서 제시되어 있다. 국내 설계기준에 제시된 가속도 증폭계수는 미국, 일본의 설계기준에서 제시된 계수와는 달리 변전소 구조물의 층수가 4층 이상일 경우에는 동적해석을 수행하여 가속도 증폭계수를 구하게 되어 있다. 국내의 변전소 구조물은 대부분 층수가 4~5층이므로 기존의 가속도 증폭계수는 실제 변전소 구조물에 적용하기에 미흡한 상황이다. 국내 변전소 구조물 형식에 적합한 가속도 증폭계수를 제시하기 위하여 대표적인 7가지 구조형식의 변전소 구조물에 대하여 가속도 증폭계수를 평가하였다. 가속도증폭 계수는 변전소 구조물에 대하여 원거리 지진과 근거리 지진을 사용하여 내부-구조물 응답스펙트럼을 작성하여 이로부터 평가하였다. 미국, 일본 전력설비 내진설계 기준에 따른 각각의 가속도 증폭계수 αj, αA는 근거리 및 원거리 지진을 사용한 동적 해석으로 구한 가 속도 증폭계수에 비하여 다소 과대평가하는 경향이 있다.
        4,200원
        419.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study evaluated the accuracy and intra-rater reliability for OWAS (Ovako Working posture Analysing System), RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment) to improve their evaluation accuracy and reliability. Participants (n = 163) with undergraduate degree were recruited in this study and trained for 6 hours about the ergonomic assessment methods. Ergonomic assessments were conducted using OWAS, RULA, and REBA for a representative work with dynamic posture found in manufacturing industries. The study compared action categories (overall level) and detailed evaluation scores for individual body part. Action categories of the participants significantly differed from the golden reference defined by ergonomic experts. The participants underrated or omitted scores for truck (37.4% of the participants) and legs (52.8%) in OWAS. Similarly, the participants underrated or omitted additional scores for all body parts except the hand and wrist in RULA (53.5%) and REBA (54.8%). On the other hand, the participants overrated scores for the hand and wrist in RULA (55.2%) and REBA (39.9%). The results found in this study can help of selecting focus points and parts during assessment and education to improve accuracy and reliability of the ergonomic assessment methods.
        4,000원
        420.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국민건강영양조사(2017) 자료를 이용하여 의사로부터 천식 진단을 받은 대상자의 자가 건강인지도, 스트레스, 2주 연속 우울감 등의 심리적 요인과 생리적 건강지표인 혈액 검사 자료를 비교하고 관련 위험요인들을 분석하였다. 연구에 사용된 국민건강영양조사(2017) 전체 대상자 수는 8,127명이며, 그 중의 성인(19세 이상) 5,852명을 대상으로 자료를 분석하였다. 일반적 특성 중 나이에 따른 천식 발생의 위험도는 65세 이상에서 높이 나타났으며(OR=1.48), 학력(OR=1.89)과 소득(OR=2.07)이 낮을수록 천식질환 발생 위험도가 증가하는 것으로 관찰되었다. 또한, 결혼 상태에서는 유배우자 동거와 비교하면 미혼(OR=1.62)과 무 배우자(사별, 이혼; OR=2.30)에서 천식 발생확률이 증가하였으며, 천식 진단군은 활동 제한(OR=2.39)이 높은 것으로 확인되었다. 심리적 요인에 있어서는 건강이 나쁘다고 인식할수록 천식 발생 유병률이 증가하였으며(OR=3.45), 우울감을 느끼는 경우도 증가하였지만(OR=1.78), 스트레스는 천식 발생 관련 위험요인이 아닌 것으로 확인되었다. 객관적 검사자료인 생리적 지표에서는 고감도 C-반응성 단백질 수치가 증가할수록 천식 발생 위험도가 증가함이 확인되었다(OR=1.12). 따라서 자가 건강인지도 및 우울감 같은 심리적 요인과 생리적 건강지표 중 하나인 고감도 C-반응성 단백질은 성인천식 질환의 잠재적 위험요인으로 인지되며, 이를 바탕으로 성인천식 질환 관리에 있어서 일반적 특성뿐만 아니라 심리적 요인 및 생리적 건강지표를 고려한 성인건강 관련 프로그램이 필요할 것으로 생각된다.
        4,000원