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Analysis of Hydrodynamics in a Directly-Irradiated Fluidized Bed Solar Receiver Using CPFD Simulation (CPFD를 이용한 태양열 유동층 흡열기의 수력학적 특성 해석)

  • Kim, Suyoung;Won, Geunhye;Lee, Min Ji;Kim, Sung Won
    • Korean Chemical Engineering Research
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    • v.60 no.4
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    • pp.535-543
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    • 2022
  • A CPFD (Computational particle fluid dynamics) model of solar fluidized bed receiver of silicon carbide (SiC: average dp=123 ㎛) particles was established, and the model was verified by comparing the simulation and experimental results to analyze the effect of particle behavior on the performance of the receiver. The relationship between the heat-absorbing performance and the particles behavior in the receiver was analyzed by simulating their behavior near bed surface, which is difficult to access experimentally. The CPFD simulation results showed good agreement with the experimental values on the solids holdup and its standard deviation under experimental condition in bed and freeboard regions. The local solid holdups near the bed surface, where particles primarily absorb solar heat energy and transfer it to the inside of the bed, showed a non-uniform distribution with a relatively low value at the center related with the bubble behavior in the bed. The local solid holdup increased the axial and radial non-uniformity in the freeboard region with the gas velocity, which explains well that the increase in the RSD (Relative standard deviation) of pressure drop across the freeboard region is responsible for the loss of solar energy reflected by the entrained particles in the particle receiver. The simulation results of local gas and particle velocities with gas velocity confirmed that the local particle behavior in the fluidized bed are closely related to the bubble behavior characterized by the properties of the Geldart B particles. The temperature difference of the fluidizing gas passing through the receiver per irradiance (∆T/IDNI) was highly correlated with the RSD of the pressure drop across the bed surface and the freeboard regions. The CPFD simulation results can be used to improve the performance of the particle receiver through local particle behavior analysis.

An Implementation of OTB Extension to Produce TOA and TOC Reflectance of LANDSAT-8 OLI Images and Its Product Verification Using RadCalNet RVUS Data (Landsat-8 OLI 영상정보의 대기 및 지표반사도 산출을 위한 OTB Extension 구현과 RadCalNet RVUS 자료를 이용한 성과검증)

  • Kim, Kwangseob;Lee, Kiwon
    • Korean Journal of Remote Sensing
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    • v.37 no.3
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    • pp.449-461
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    • 2021
  • Analysis Ready Data (ARD) for optical satellite images represents a pre-processed product by applying spectral characteristics and viewing parameters for each sensor. The atmospheric correction is one of the fundamental and complicated topics, which helps to produce Top-of-Atmosphere (TOA) and Top-of-Canopy (TOC) reflectance from multi-spectral image sets. Most remote sensing software provides algorithms or processing schemes dedicated to those corrections of the Landsat-8 OLI sensors. Furthermore, Google Earth Engine (GEE), provides direct access to Landsat reflectance products, USGS-based ARD (USGS-ARD), on the cloud environment. We implemented the Orfeo ToolBox (OTB) atmospheric correction extension, an open-source remote sensing software for manipulating and analyzing high-resolution satellite images. This is the first tool because OTB has not provided calibration modules for any Landsat sensors. Using this extension software, we conducted the absolute atmospheric correction on the Landsat-8 OLI images of Railroad Valley, United States (RVUS) to validate their reflectance products using reflectance data sets of RVUS in the RadCalNet portal. The results showed that the reflectance products using the OTB extension for Landsat revealed a difference by less than 5% compared to RadCalNet RVUS data. In addition, we performed a comparative analysis with reflectance products obtained from other open-source tools such as a QGIS semi-automatic classification plugin and SAGA, besides USGS-ARD products. The reflectance products by the OTB extension showed a high consistency to those of USGS-ARD within the acceptable level in the measurement data range of the RadCalNet RVUS, compared to those of the other two open-source tools. In this study, the verification of the atmospheric calibration processor in OTB extension was carried out, and it proved the application possibility for other satellite sensors in the Compact Advanced Satellite (CAS)-500 or new optical satellites.

A Study on the Types of Jazz Performance Audiences Using Q Methodology (Q 방법론을 적용한 재즈공연 관객의 유형에 관한 연구)

  • Jeong, Woo Sik
    • Korean Association of Arts Management
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    • no.53
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    • pp.5-45
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    • 2020
  • This study aims to deeply analyze the subjective attitude of jazz performance audiences in Korea using Q methodology. In order to establish a population for the research, we decided 'People's mind about jazz performances' as the main topic and finally selected a Q model consist of 38 statements after having a depth interview with corresponding experts. Additionally, from January to February 2019, we implemented a Q-sorting and individual interview to total of 27 people including people majored in music, jazz club members and other citizens. The result were the following. First of all, a musical-interest oriented type. People of this type understood watching jazz performance as a daily leisure activity and went to watch a show more than once a month on overage. Those people obtained information of performances and actors before attending a show using social network such as SNS and jazz clubs. They also had a big desire to have an emotional interaction with jazz musicians while having a fan signing event or performance. Secondly, a general-interest oriented type. This type of people had a tendency of considering watching a jazz performance as a especial experience and not a daily life event. Attending a jazz performance was a novel experience which could be done with their close friends in a special day. Thirdly, people with self-value oriented type. This people were majored in jazz and classic in their universities. As they had a concrete perspective, professional knowledge and experiences, they were more sensitive on the general quality of the performances such as show's sound, light, video, sound system of the theater, player's ability, level of facilities, accessibility, etc. rather than the reputation of an artist. This research did not only revealed jazz audience's subjective tendency using Q methodology but also demonstrated the types of jazz audiences and their characteristics. Therefore, this could be a meaningful study for suggesting a significant implication for the marketing mix of performance planning on each jazz audience type.

A Study on the Art Education Program Based on Cultural Diversity: Focused on the Case of National Museum of Modern and Contemporary Art, Korea (서울어젠다 기반 문화다양성 미술관교육 프로그램 분석 및 방향 - 국립현대미술관 사례를 중심으로 -)

The Direction of Job Policy Development for Korean Golf Professionals (한국 골프전문인력의 일자리 정책 발전방안)

  • Cho, Jung-Soon;Suh, Ah-Ram
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.4
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    • pp.289-303
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    • 2020
  • The purpose of this study is to provide adequate datas on number of people who are in golf related field and also further expend that number for golf industry. The main stream of this study is to map out present golf related jobs and how this study can help golf industry in general. To make a greater improvements on golf industry with more job opportunity following ideas were presented. First, improving education on "hand on experiences on the field of golf industry" Better educating potential employees for golf industry for the right positions can enhance overall work environment. To do so, the society and the schools must come to agreement to provide adequate curriculum for people. Second, implementing "a golf club division program." The support from Ministry of Culture and Sports and Tourism Department, which are govern by Republic of Korea, are aggressively working to expend the golf business and also recruit elite personnel like former tour players to work on the field to better operate the whole system. Third, performing a thorough research on current golf related jobs and numbers and diversity on the field. Fourth, developing a specific and a differentiated golf job fields for better future for people and students who majored in golf industry. So that they cam feel secured and have a sense of dignity. Finally, strengthening the golf industry's competitiveness. The golf related companies have to step up to higher gear. With working in harmony between golf industry and government can assure of brighter future for our next generation.

The Relationship Between Viewing Value and Viewing Satisfaction According to the Factors for Viewing Dance Performances (무용공연 관람요인에 따른 관람가치와 관람만족 관계)

  • Baek, U-Young;Cho, Dong-Min;Lee, Sang-Ho
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.4
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    • pp.237-250
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    • 2020
  • The purpose of this study was to investigate the relationship between the performance factors of dance performance and the intention to revisit the audience, and to investigate the structural relationship between viewing satisfaction and viewing value. For data processing, SPSS Ver. 21.0 and AMOS Ver. The program of 21.0 was used. Structural relationships were analyzed using a two-step approach, and the significance of the effects was verified using bootstrapping. In addition, a full mediating effect and a partial mediating effect were presented using the three-step regression analysis mediating effect. The results of the study are as follows. First, it was found that the viewing factors influenced the viewing satisfaction and the viewing value. Second, it was found that viewing satisfaction had an intention to revisit and influenced the viewing value. It was also found that the viewing value had an effect on the intention to revisit. Third, in the relationship between the viewing factors of the dance performance and the viewing value, it was found that the viewing satisfaction had a partial mediating effect. Fourth, it was found that the attendance factor of the dance performance was not related to the intention to revisit. However, it was found that the satisfaction of viewing and the value of viewing had a complete mediating effect in relation to the viewing factors of dance performances and the intention to revisit. Through these studies, the dance performance should overcome the inherent limitations of space-time limitations and present basic data for establishing a mid- to long-term marketing strategy that can respond quickly.

Association Between Suicide and Diet (자살과 식단의 연관성)

  • Eunji, Lim;Bong-Jo, Kim;Cheol-Soon, Lee;Boseok, Cha;So-Jin, Lee;Jae-Won, Choi;Young-Ji, Lee;Nuree, Kang;Dongyun, Lee
    • Korean Journal of Psychosomatic Medicine
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    • v.30 no.2
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    • pp.73-79
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    • 2022
  • Objectives : Suicide is a global social problem. Social burden caused by suicide is gradually increasing. Various efforts have been made to prevent suicide. Lifestyle changes to western style, especially diet changes, have increased the risk for suicide. Therefore, in this study, we discussed diet as an adjuvant treatment for suicide. Methods : In this review, we summarized the biochemical mechanism of suicide, and diet as a risk factor for suicide and diet as a protective factor through a web search. Results : In this study, biochemical mechanisms for suicide were reviewed and diet as a risk factor and diet as a protective factor for suicide were investigated. It was confirmed that neurotoxic effects such as oxidative stress and inflammation in the neural system could increase the risk of suicide. Based on results of previous studies on the relationship between suicide and diet, it was found that heavy use of alcohol, coffee, carbonated soft drink, and fast food were risk factors for suicide. Protective factors for suicide included antioxidants such as vitamin C, carotene, and anti-inflammatory agents such as omega-3 fatty acids found in seafood in large amounts. Conclusions : The only treatment for suicide is prevention. In this context, effectiveness, accessibility, and safety are important for preventing for suicide. Antioxidants and anti-inflammatory agents that are relatively safe and readily available to the public could be effective adjuvant treatments to decrease the risk of suicide. In addition, it is necessary to educate the public on reducing diets that could increase the risk of suicide

Study on Spatial Change of Urban Forest Considering Definition of Urban Area in South Korea (도시지역 정의에 따른 도시숲의 공간적 변화에 관한 연구)

  • Doo-Ahn, KWAK;So-Hee, PARK
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.4
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    • pp.19-31
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    • 2022
  • The definition of urban forest is described as all forest and trees except the Natural Parks throughout whole territory in Urban Forest Act. But the concept of urban forest in the law differs from general awareness by Korean citizen and from definitions of other countries. For discussing such differences of urban forest definition, it was tested how much urban forest area would be changed according to the various definition of urban area. The urban area was defined to be four scenarios in this study in consideration of "urban area" by National Land Planning and Utilization Act (NLPUA), 300m buffered boundary from the "urban area" proposed by World Health Organization (WHO) and forest watershed area. In the scenario 1, including forest watershed intersected with "urban area" by NLPUA, urban forest area was estimated at 1.83 million ha in which urban forest area per person was 386㎡. In the scenario 2, including forest watershed intersected with 300m buffered boundary from the "urban area" by NLPUA, urban forest area was estimated at 1.92 million ha in which urban forest area per person was 405㎡. In the scenario 3, including forest watershed intersected with "urban area" placed within administration boundary (Eup·Dong districts), urban forest area was estimated at 1.08 million ha in which urban forest area per person was 230㎡. In the scenario 4, including forest watershed intersected with 300m buffered boundary from "urban area" placed within administration boundary, urban forest area was estimated at 1.20 million ha in which urban forest area per person was 256㎡. Therefore, the boundary of urban area should be agreed clearly prior to defining the urban forest area for avoiding unclear area calculated according to different definitions.

Comparison of Egg Productivity, Egg Quality, Blood Parameters and Pre-Laying Behavioral Characteristics of Laying Hens and Poor Laying Hens (산란계와 과산계의 난생산성, 계란품질, 혈액 특성 및 산란 전 행동 특성의 비교)

  • Woo-Do, Lee;Hyunsoo, Kim;Jiseon, Son;Eui-Chul, Hong;Hee-Jin, Kim;Hwan-Ku, Kang
    • Korean Journal of Poultry Science
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    • v.49 no.4
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    • pp.189-197
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    • 2022
  • This study was conducted to compare the egg productivity, egg quality, and blood characteristics of laying hens with different laying rates, and the frequency and cumulative duration of the sitting behavior observed before laying was investigated. Twelve 45-week-old Hy-Line Brown laying hens were randomly assigned to two treatment groups with three replicates. Treatment groups were classified as layers laying over 80%(high egg performance layers; HEP) and layers laying below 50%(poor egg performance layers; PEP). The experiment lasted 4 weeks. HEP showed higher hen-house egg production ratio and egg mass and lower feed conversion ratio(FCR) (P<0.05) compared with PEP, although egg weight was higher in PEP (P<0.05). In terms of egg quality, PEP showed differences in eggshell quality (eggshell color, eggshell thickness, and eggshell weight) (P<0.05). Additionally, HEP showed high triglycerides(TG), and PEP showed high alanine transaminase(ALT) level (P<0.05) in serum collected in the morning. In the afternoon, the HEP showed higher lactate dehydrogenase(LDH) levels (P<0.05). No differences in the Ca: P ratio were observed between layers with different laying rates. One hour before egg laying, HEP exhibited sitting behavior 4 times on average, each lasting 25 minutes. In conclusion, egg production and quality differ between HEP and PEP, and HEP showed frequent sitting behavior before egg laying. However, additional research is necessary to explore approaches other than specific behavioral observation to distinguish poor layers in the flock for application in farms.

A Development of Facility Web Program for Small and Medium-Sized PSM Workplaces (중·소규모 공정안전관리 사업장의 웹 전산시스템 개발)

  • Kim, Young Suk;Park, Dal Jae
    • Korean Chemical Engineering Research
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    • v.60 no.3
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    • pp.334-346
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    • 2022
  • There is a lack of knowledge and information on the understanding and application of the Process Safety Management (PSM) system, recognized as a major cause of industrial accidents in small-and medium-sized workplaces. Hence, it is necessary to prepare a protocol to secure the practical and continuous levels of implementation for PSM and eliminate human errors through tracking management. However, insufficient research has been conducted on this. Therefore, this study investigated and analyzed the various violations in the administrative measures, based on the regulations announced by the Ministry of Employment and Labor, in approximately 200 small-and medium-sized PSM workplaces with fewer than 300 employees across in korea. This study intended to contribute to the prevention of major industrial accidents by developing a facility maintenance web program that removed human errors in small-and medium-sized workplaces. The major results are summarized as follows. First, It accessed the web via a QR code on a smart device to check the equipment's specification search function, cause of failure, and photos for the convenience of accessing the program, which made it possible to make requests for the it inspection and maintenance in real time. Second, it linked the identification of the targets to be changed, risk assessment, worker training, and pre-operation inspection with the program, which allowed the administrator to track all the procedures from start to finish. Third, it made it possible to predict the life of the equipment and verify its reliability based on the data accumulated through the registration of the pictures for improvements, repairs, time required, cost, etc. after the work was completed. It is suggested that these research results will be helpful in the practical and systematic operation of small-and medium-sized PSM workplaces. In addition, it can be utilized in a useful manner for the development and dissemination of a facility maintenance web program when establishing future smart factories in small-and medium-sized PSM workplaces under the direction of the government.