Numerical analysis has been carried out to investigate the characteristics of seawater flow fields and turbine output in a compact double current tidal power generation system for various level differences. There are growing concerns for the development of efficient tidal power generation which is stable and less affected by environmental circumstances as ocean energy. Especially the flow field characteristics in the compact tidal power generation system have a large influence on the system power generation performance. Flow velocity, pressure, and streamline distributions are compared including vertical type turbine out, and it can be predicted that seawater is accelerated by vortex flow in front of the turbine and there is severe turbine output variation due to the water level difference with pressure difference. These results can be applied as basic data for the effective development of compact tidal power generation system.

In this study, the analysis of the unsteady viscous flow field using the uRANS equation in a moving mesh was studied. The simulation domain is composed of an overset zone fixed to a propeller and rotating at a constant angular speed and a far zone which is located in the far distance and does not move. Each zone is composed of a polyhedral meshes for the accurate and robust gradient calculation in addition to the reduction of computation time. Simulation technique was applied to the aerodynamic analysis of the 5-inch propeller and compared with those of the MRF and the thrust test. The thrust predicted by the moving mesh showed good correlation with the MRF result within 0.5% difference, but the torque showed a tendency to under-prediction by about 10% compared to the MRF. In the future, we plan to further validate the numerical analysis technique using the moving mesh by applying it to the configurations in which precise test results exist.

This paper considers the influence of internal heat exchanger and capillary tube on the efficiency of small refrigeration system using eco-friendly refrigerants such as R290, R600a, R1270, and R717. A refrigeration system using such internal heat exchanger and capillary tube may improve performance, but may degrade performance. Therefore, this paper used a mathematical model in a normal state to understand performance characteristics as to what change occurs when internal heat exchanger and capillary tube are attached to eco-friendly refrigerant based on R134a. In addition, the effects of operating conditions such as refrigerant flow rate, evaporation temperature, condensation temperature, subcooling degree internal heat exchanger length and capillary tube length were analyzed. The result showed that the evaporation temperature, condensation temperature, subcooling degree, internal heat exchanger length and capillary tube length had an effect on the refrigeration capacity and compression power. Therefore, it is necessary to design a refrigeration cycle using an eco-friendly refrigerant by grasping these effects in detail.

A wire rod, a material for multistage cold forging, is subjected to spheroidization and low annealing heat treatment to secure formability, and a phosphate coating treatment on the material surface to secure lubricity. The film layer produced by the phosphate treatment process is involved in adhesion to the material surface, adhesion to the forging die surface, and lubricity. This results in the increase or decrease of the forming load and the increase or decrease of the die life in the cold forging process. In particular, as the cold forging process progresses, the phosphate film is damaged and the original performance is deteriorated, so there is a high possibility of process defects. In case of excessive damage, the film is completely lost and die soldering occurs. Therefore, in this study, quantitative criteria for phosphate film damage are presented and the effect on the cold forging process is analyzed based on this to improve process analysis prediction accuracy. Therefore, in this study, quantitative criteria for phosphate film damage are presented, and based on this, the friction coefficient in the multi-stage cold forging process is to be derived.

본 연구는 현대 과학 교육의 탐구 활동에서 관찰 또는 탐색의 역할이 강조되고 있는 것과 과학 탐구 소재 확장의 필요성에 의해 진행되었다. 이에 본 연구는 예술 작품을 활용한 탐구 프로그램을 개발, 적용하여 귀추 과정 중 학습 자들의 탐색 특징을 자세히 분석했다. 동양화, 서양화, 신화, 관현악, 전통 가옥을 소재로 한 ‘미술관으로 간 과학자’ 프로그램이 개발되었으며, 방과 후 과학 교실에 다니는 중학생 5명이 참여했다. 연구 결과, 작품 속 주목할 만한 현상을 탐색한 학습자들은 탐색 특징에 따라 크게 세 유형으로 나뉘었다. 과학 개념에 쉽게 연결할 수 있는 내용을 관찰, 기술한 학습자가 있는 반면, 과학 개념과 상대적으로 거리가 먼 일상적 요소를 주로 관찰한 학습자도 있었다. 자신들의 주관적 평가와 의견을 바탕으로 작품을 탐색한 학습자도 있었는데 이들은 자신의 감상 의견을 중심으로 작품을 탐색하는 특징을 보였다. 연구의 결론 및 시사점으로 탐구 활동에서 시각적으로 관찰할 수 없는 소재의 비적합성, 학습자들의 선지식이 탐색 활동에 미치는 영향, 지구과학 탐구 소재의 확장 가능성 등을 제시했다. 본 연구는 천문학을 중심으로 한 귀추 탐구에서 학습자들의 탐색 특징을 살펴봄으로써 다양한 내용과 방법의 지구과학 학습을 제시하고, 특히 귀추가 천문 학습에 적절히 활용될 수 있는 가능성을 제시한다.

본 연구는 부산광역시를 대상으로 열환경을 개선하기 위한 바람길 관리 방안 제안을 목적으로 한다. 이를 위해, Landsat-7 위성 열영상 자료와 공간통계 분석을 실시하여 부산광역시의 Hot spot과 Cool spot 지역 특성을 파악하였으며, WRF 기상모의를 통해 주요 바람길을 분석하였다. 그 결과, Hot spot 지역 중 열환경 개선이 요구되는 지역은 부산진구, 동래구, 연제구와 사상구 공업지역, 대규모 시설지역에는 부산항 부두로 나타났으며 주요 바람길에는 금정산~백양산~ 구덕산 계곡부로서 확인되었다. 이를 바탕으로 바람길 관리 전략을 제시하면 다음과 같다. 공업시설과 부산항 일대는 대기 온도 상승 요인으로서 주변 지역의 열환경을 악화시키므로 시설의 온도저감 및 바람길을 고려한 도시·건축계획이 요구된다. 바람길 관리가 필요한 지역으로 만덕동, 사직동 일대 산림에 대한 추가적인 훼손이 일어나지 않도록 하여야 하며, 산림과 인접한 지역의 대규모 고층아파트는 산림에서 생성된 차고 신선한 공기의 흐름을 방해하므로 금정산과 접해있는 제3종 일반주거지역의 신규·재개발에 따른 고층아파트 단지 조성은 지양해야 한다. 본 연구 결과는 부산광역시의 기후변화에 대응한 도시계획 및 환경계획수립 시 기초자료로 활용할 수 있을 것으로 기대한다.

The purpose of this study was to compare and analyze the importance and satisfaction of consumer selective attributes by home meal replacement (HMR) types using local ingredients. This study was conducted from December 4 to December 8, 2020. A total of 380 responses organized according to preferred types of HMR (100 for Ready to Eat (RTE), 92 for Ready to Heat (RTH), 88 for Ready to Cook (RTC), 100 for Ready to Prepared (RTP) were used for the final analysis. Statistical analysis was conducted by descriptive analysis, paired t-test, and importance-satisfaction analysis by HMR type. Findings of this study showed significant differences in consumer selective attributes by HMR type. RTE and RTC need to improve quality while RTH needs to improve quality and packaging. Notable selective attributes were quality, packaging, and information. They were located in different quadrants of each HMR type. All other attributes appeared in the same quadrant. Further research is needed to determine differences in quality, packaging, and information for each HMR type. Results of this study provide basic data for developing products and marketing strategies for each type of HMR products using local ingredients.

Unhealthy dietary behavior such as insufficient calcium intake can be one of risk factors of osteoporosis and chronic diseases in older people. This study evaluated the recent trends in dietary calcium intake and the food source in Korean adults aged 50 years or older using the Korea National Health and Nutrition Examination Survey (KNHANES, 2015-2019) data. This study used 24-hour recall survey data to investigate the calcium intake, the major food groups and main dishes contributing to the calcium intake. The mean calcium intake was 479.55-506.81 mg/day. The major food groups that contribute to calcium intake were vegetables, milks and fishes. Dairy and frozen desserts and kimchi were the major dish groups that contributed to the calcium intake. Calcium intake from milk in dairy and frozen dessert group has been high in last 5 years (50-64 years old: 34.71-47.68 mg, 65-74 years old: 29.72-43.65 mg, over 75 years old: 22.91-42.93 mg). In addition, baechu-kimchi is the most contributed to the calcium intake in kimchi group (50-64 years old: 35.10-41.47 mg, 65-74 years old: 29.62-34.96 mg, over 75 years old: 23.79-29.13 mg). In conclusion, various source of calcium needs to be recommended to increase intake calcium in over 50 years, which may reduce chronic diseases and improve quality of life.

Institutional foodservice is a type of meal provided to workers in industry and affects the health and psychological wellbeing of workers and productivity. Thus, research on customer satisfaction with institutional foodservice is important. In addition to food industry and food culture developments, the requirements of institutional foodservice customers are diversifying due to COVID-19. Therefore, the purpose of this study was to identify factors that affect customer satisfaction with institutional foodservice using a user-based approach. In this study, the quality of institutional foodservice was defined using customer satisfaction or dissatisfaction, and by using in-depth interview and open coding (a qualitative research method), we derived qualities of institutional foodservice from the user’s perspective and compared these with those of previous studies. This study is meaningful as the quality of institutional foodservice was analyzed using a user-based approach, in-depth interview, and open coding and compares results with those of previous studies.

Due to the global climate change, Korean peninsula is has been experiencing flooding and drought severely. It is hard difficult to manage water resources sustainably, because due to intensive precipitation in short periods and severe drought has increased in Korea. Reused water from the wastewater treatment plant (WWTP) could be a sustainable and an alternative water source near the urban areas. In order to understand the patterns of water reuse in Korea, annual water reuses data according to the times and regional governments were investigated from 2008 to 2019. The reused water from WWTP in Korea has been mainly used for river maintenance flow and industrial use, while agricultural use of water reuse has decreased with time. Metropolitan cities in Korea such as Seoul, Busan, Daegu, Ulsan, and Incheon have been mainly used reused reusing water for river maintenance flow. Industrial water reuse has been limitedly applied recently for the planned industrial districts in Pohang, Gumi, Paju, and Asan. By using the collected annual water reuse data from the domestic sewerage statistics of sewerage, the optimistic and pessimistic future estimations of for future annual water reuse were suggested from 2020 to 2040 on a five year interval for every five years.

This study investgates Korean water technology through the water market perspective and analyses its competitiveness. Based on the water technology classification, water technology competitiveness is analysed through the technological influence index and market dominance index which are based on the extracted water technology patents from the US, Europe, Korea, and Japan for the last decade. As a result, the Korean water technology patents were lack in influence and competitiveness in global market considering the large volume of patents. There are two most tech-influential industries in Korea; manufacturing industry consisting pipes, sterilization, disinfection, and advanced water purification equipment, and construction industry including seawater desalination and water resource development. Due to the domestic usage of the patents, the Korean water technology patents scored low in global market PFS(Patent Family Size) index compared to their CPP(Cites Per Patent) index. The study is meaningful in a way that the analysis on Korean water technology competitiveness using water technology classification system and patent analysis was conducted based on the perspective of the global water market.

선행연구를 통해 침수에 대해 저항성과 감수성을 나타내는 야생콩계통을 선발하고 난 뒤 이들 자원들간 지상부 및 지하부 특성을 분석하였고, 유전자의 발현량도 비교 분석하였다. 1. 연구결과, 침수에 대해 저항성을 나타낸 ‘CW11598’과 감수성을 나타낸 ‘CW11948’는 알코올 발효를 촉매하는 PDC와 ADH효소의 활성을 조절하는 mRNA 발현량에서 차이를 보였다. 감수성계통에서 PDC와 ADH 활성을 조절하는 유전자 모두 침수처리에서 무처리보다 유전자 발현량이 감소하였고, 저항성계통해서는 침수처리에서 오히려 무처리보다 이들 유전자의 발현량이 증가하였다. 이런 침수스트레스 대체 경로의 차이는 감수성계통에서 침수처리 무처리보다 줄어든 LSA, TRL 및 RSA로 나타났다. 2. 식생지수 NDVI와 PRI 모두 감수성계통이 침수처리에서 무처리 대비 크게 감소하였다. 하지만 저항성계통에는 LSA는 침수처리와 무처리간 차이가 없었고, 식생지수 NDVI와 PRI도 침수처리와 무처리간 차이를 보이지 않았다. 하지만 TRL와 RSA는 침수처리에서 무처리보다 감소한 것으로 조사되었다.

DMZ가 생성된 이래 북한의 도발 및 남북무력충돌이 발생해 남북간 군사적 긴장이 가장 높았던 시기가 바로 1960∼70년대였다. 정전협정 체결 후 1960∼70년대 북한 무력도발은 ①남조선혁명의 일환으로 획책, ②체제결속의 강화 차원에서 지속, ③남북분단 고통의 심화·확대의 초래 등의 특징을 갖고 있다. 북한의 대남전략 및 무력도발이 주는 시사점은 ①북한의 위장평화공세에 대한 철저한 대비, ②북한의 어떤 무력적화도 발에 대해서도 유연하게 대응할 수 있는 안보능력 강화, ③통일지상주의 및 근거 없는 낙관론의 지양, ④북한의 변화를 위한 점진적·단계론적 접근의 추진 등으로 요약해 볼 수 있다. 우리의 국방은 항상 최악의 상황 까지도 대비할 수 있어야 한다. 우리는 언제라도 북한의 무력도발을 억제하고 유사시 안정적으로 대처할 수 있는 자조적·공조적 국방안보능력 강화에 최선의 노력을 다해야 할 것이다.

The purpose of this study is to analyze the research trends in Korean education for learners in the Arab region. This paper also suggests directions for the future research on the field of Korean education for these learners. To conduct this study, a process of collection and sorting of research papers was held as the first step. Consequently, 64 papers were chosen. Among 64 papers, 31 academic journals and 33 theses were included. The study then reviewed the research trend by years, publishing types, and topics. Although there were very few studies in the 2000s, the number of studies has steadily increased after 2010. This was related to the Korean Wave in Arab countries and the increase in Arab students who study in Korean from 2013. In the topic analysis by the topics, ‘Teaching and Learning’ accounted for the largest proportion. The second largest proportion was ‘Korean Education Content’. Next was ‘Korean Education in general’, followed by ‘Contrastive Analysis’. Overall, there have been many studies based on contrast or error analysis between Arabic and Korean languages. In terms of contents, there were many studies on phonetics and culture. However, it was found that there are many studies that need to be addressed in each sub-topic. Lastly, based on the analysis in this study, the characteristics and limitations of research trends were analyzed, and future research directions were suggested.

PURPOSES : This study was conducted to analyze the driving width of the vehicle body and off-track width of front-rear tires when a large vehicle or an articulated bus passes through a roundabout. METHODS : The driving width was measured using two methods considering the off-tracking tire and the size of the vehicle body. The test conditions of the roundabout were considered as follows: number of entry/exit sections (three-legs roundabout and four-legs roundabout), number of lanes (one lane and two lanes), driving speed (10 km/h, 20 km/h, and 30 km/h), driving trajectory (centerline and maneuver), and driving path (right turn, straight, left turn, and U-turn). The driving trajectories of large buses or articulated buses were analyzed using a road design simulation tool (AutoTURN Pro). RESULTS : Consequently, it was observed that the driving width calculated using the off-track width of the front and rear tires was lower than that analyzed for the vehicle body. The width was smaller in the case of driving in the one-lane roundabout than that in the two-lane roundabout. In particular, it was analyzed that the situation in which the turning path invades the lane appeared in left-turn (East → South) and U-turn (East → East) situations. The width was narrower in the case of driving in the one-lane roundabout than that in the two-lane roundabout. CONCLUSIONS : The study results are expected to be applied for designing roads when large buses or articulated buses are selected as design vehicles.

Learning Chinese through animation can be of great help to balanced language learning as you can access not only language but also culture. This study extracted and analyzed the vocabulary of the July 8th, 2016 Chinese animation [Big Fish & Begonia] as evaluated by HSK grade. Among the total number of vocabularies and expressions observed, the average proportion of the ‘basic HSK’ grade vocabulary is 53.95% and the average proportion of the ‘modified HSK’ grade vocabulary is 96.98%, which is very meaningful in learning. The composition ratio of HSK grade for each section was generally constant and the difficulty was constant. The animation [Big Fish & Begonia] contains various vocabulary for learning Chinese and is an educational content that embodies the cultural colors and characteristics of China well for children and adult learners in the early stages of learning Chinese. A very positive educational effect can be expected for the development of Chinese language skills, and the possibility of its use is also very high.

Este trabajo analiza los errores debidos a la interferencia coreana al escribir/traducir al español. Sostenemos que, cuando los alumnos ingresan una vez en la memoria una forma española α que corresponde preferentemente a una forma coreana A, tienden a equiparar esta correspondencia como ‘A = α’ y la aplican a los casos en los que dicha correspondencia no debería usarse. Para averiguar cuántos alumnos cometen este tipo de error, realizamos un experimento con 42 alumnos. En el experimento, dividimos las oraciones en dos grupos. Las oraciones que pueden producir un resultado apropiado se colocaron en el grupo A si usamos la correspondencia ‘A → α’, mientras que las que pueden producir un resultado inapropiado se ubicaron en el grupo B si lo hacemos. Nuestro análisis mostró que el error más común del grupo B es reutilizar la correspondencia utilizada en el grupo A. Por lo tanto, los estudiantes necesitan evitar una “ecuación excesiva” para reducir errores. Finalmente, para cada oración, sugerimos formas de reducir o evitar errores.

이 연구는 최근 4차 산업혁명의 도래로 인해 교정업무의 효율성을 확보하고 증가하는 교정수요를 충족하기 위한 방안으로 각광 받고 있는 스마트 교정 개념에 대해 정의 하고, 과학기술전문가와 현직 교정공무원을 대상으로 AHP 분석･설문조사를 실시하여 스마트 교정에 우선적으로 필요한 교정업무 분야와 개발이 필요한 과학기술의 우선순 위를 확인하였다. 분석결과를 바탕으로 새로운 교정업무 패러다임인 스마트 교정이 교정업무에 적용되기 위해 필요한 개선방안을 제안하는 것이 연구의 목적이다. 이러한 목적을 달성하기 위해 국내외 스마트 교정에 대한 문헌연구를 실시하고, 과학기술에 대한 현황을 확인하였다. 분석결과를 바탕으로 국내 교정현실에 맞는 스마트 교정의 적용방안을 제시하기 위해 교정분야별 R&D 연구에 대한 중장기 계획 수립･기반조 성 방안･법률안 개정 방안을 도출하여 이에 대한 정책적 방안으로 제시하였다.

PURPOSES : The logistic roads for freight transport along to the new port of Busan have been suffered by the rapid weather changes including high temperature and torrential rain. As a result, the roads require annual repair, which have been distressed seriously by the heavy logistic and environmental loads. Therefore, we need to identify the cause of the road pavement distresses and find a proper design method to minimize the pavement distress in order to prohibit the problem aggravated. METHODS : The damaged conditions of the logistic roads were investigated on-site. In addition, applied pavement designs, real traffic volumes, and historical climatic information were intensively collected for this project. With the investigated and collected data Korean pavement design program (KPRP) was implemented to analyzed the causes of the damaged roads and conceive the pavement design draft optimized for the roads. RESULTS : According to the investigation and KPRP analysis, the traffic volume to transport freights impacts significantly the pavement distress, so that a higher PG grade binder type should be used, for which polymer modified asphalt (PMA) binders are recommended. Moreover, its pavement thickness should be increased to secure load bearing capacity, but thickening the pavement has been discouraged due to difficulties induced by the road-sectional change, especially road-height change. CONCLUSIONS : In conclusion, 5cm PMA overlay is suggested for the normal-scale maintenance, and 7cm PMA overlay for large-scale maintenance. Besides these, the application of Polymer-modified Stone Matrix Asphalt (PSMA) using PG76-22 binder would be the best preventive maintenance method, which has been well know as having higher fatigue resistant performance than general PMA. However, if we use PSMA, quality control should be very cautious since PSMA can be very susceptible premature distress if its production and construction are improperly proceeded.

최근 사회적으로 요구하고 있는 기업의 역할이 확대됨에 따라 기업의 비재무적인 경영활동(ESG)은 기업의 존폐를 좌우할 수 있는 주요 경영 평가지표로 등장하게 되었다. 하지만, 국내 주요 기업들이 이러 한 사회적 변화에 대응하고자 ESG 경영을 선언하고 다양한 경영전략을 수립하고 있지만 여전히 정부나 공공기관은 표준화되거나 일관된 ESG 경영 평가지표를 제시하지 못하고 있다. 이에 본 연구는 ESG 경영 활성화을 위한 인적자원관리의 역할에 주목하여 국내외 ESG 경영 평가지표를 비교분석하여 향후 인적자원관리 차원에서의 ESG 관련 연구 주제와 방향성을 제시하고자 한다. 이를 도출하기 위해 우선 인적자원관리 관점에서 ESG 경영에 대한 중요성과 ESG 경영에서의 인적자원관리의 역할, ESG 관련 연구 동향을 살펴보았다. 이후 국내외 대표적인 ESG 평가기관들의 평가지표 비교분석을 통해 함의를 찾고 최근 국내 ESG 평가지표의 변화를 토대로 인적자원관리 차원에서의 연구 주제를 확장하고자 하였다. 본 연구의 결과 첫째, ESG 경영에서 인적자원관리가 중요한 이유는 ESG 경영 평가에 있어서 인적자원관리 지표가 큰 비중을 차지하고 있고 ESG 평가상에서의 대부분의 핵심지표들이 조직문화와 연계되어 있다는 것이다. 둘째, ESG 인적자원관리 부문의 평가지표는 기업이 처한 환경에 따라 차이가 있고 시대적 상황에 맞게 변화한다는 점이다. 셋째, 인적자원관리 관점에서의 ESG 연구는 국내외 간의 평가지표 지향성의 차이를 통해 확산적 가치와 수렴적 가치를 국가간 비교 할 수 있는 연구, 국내에 있는 외국계기업의 ESG 경영전략 수립 기준 연구, 인적자원관리 관점의 ESG 평가지표와 경영성과 간의 관계 연구, 마지막으로 폭 넓은 의미에서 인간존중 경영, 안전보건(사고), 직장 내 갑질, 조직 내 MZ세대와의 갈등, 리더십, 조직문화까지 폭넓은 스펙트럼을 지표화 할 수 있는 연구 등으로 확대해야 한다는 것이다.