• Title/Summary/Keyword: 한계해석

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Numerical Study on Performance of PEMFC with Block and Sub-channel of Cathode Flow Field (캐소드 유로에서 블록과 서브 채널의 고분자전해질 연료전지의 성능에 관한 전산해석 연구)

  • Jo, Seonghun;Kim, Junbom
    • Applied Chemistry for Engineering
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    • v.32 no.6
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    • pp.613-620
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    • 2021
  • A flow channel shape of PEMFC has an influence on the internal flow uniformity. If the reactant distribution in a flow path is not uniform during operation, both catalyst deactivation and mechanical damage of membrane could occur resulting in decreasing the membrane electrode assembly (MEA) durability. Numerous studies concerning flow design have been conducted to make smooth supply and uniform distribution of reactants in fuel cells. The baffle of flow path could improve fuel cell performance through the forced convection effect. A sub-channel, as an additional air flow path, could increase the reactant concentration and reduce the mass transfer loss via a smooth water discharge. In this study, computational fluid dynamics (CFD) was used to analyze the effect of blocks and sub-channels on the current density and oxygen concentration of the fuel cell. As a result, the limit current density and oxygen concentration at a rear block increased when using blocks and sub-channels in a flow channel. In particular, the current density increased significantly when the sub-channel was placed between two blocks. Also, the sub-channel position was optimized by analyzing the oxygen concentration, and the oxygen concentration was recovered at a rear block in the fuel cell.

The effect of Service climate on Customer emotion and Customer satisfaction (기업의 서비스 풍토가 고객감정과 고객만족도에 미치는 영향)

  • Kang, Kun-Myong;Hong, Jung-Wan
    • Journal of Convergence for Information Technology
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    • v.11 no.9
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    • pp.65-74
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    • 2021
  • In this study, we further study the customer's positive emotion about the impact of different inherent service climate on the emotions and satisfaction of the customers who receive the service. Through this, the purpose was to present the direction of creating a service climate. As a research method, structural equation statistical analysis, such as measurement model analysis and structural model analysis, was performed using SmartPLS (v.3.2) for data collected in surveys. Looking at the research results, first, a company's service climate has a positive (+) impact on positive customer emotions: pleasure, pleasure, and happiness. This can be interpreted as an indication that creating a business climate for service is an important factor that elicits positive emotions from customers. Second, a company's service climate and positive customer emotion also have a positive impact on customer satisfaction. Finally, when a company's service climate affects customer satisfaction, happiness has the greatest mediating effect among several parameters. This demonstrated empirically that satisfying the happy feelings of customers is the most important of the company's service climate. Since this study is aimed at a small number of restaurant companies, there is a limit to generalizing the findings and applying them to all restaurant companies. Nevertheless, it is meaningful to study the emotions of positive customers when the service climate affects customer satisfaction, and we hope that the company's analysis of service climate will continue to improve customer satisfaction through various emotional analysis as well as positive factors.

The Effect of Consultant competency on the Project performance and Social-relational competency : focus on ICMCI competence framework (컨설턴트역량이 프로젝트성과와 사회관계역량에 미치는 영향 : ICMCI 역량프레임워크를 중심으로)

  • Hong, Yong-Ki;You, Yen-Yoo;Kim, Sang-Bong
    • Journal of Convergence for Information Technology
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    • v.11 no.10
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    • pp.302-313
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    • 2021
  • As the domestic consulting industry matured, consultants were required to have insight into customer's business and consulting business. Gaining these insights requires deep understanding of the business domains and high degree of competencies. This study empirically analyzed the data collected through the survey in order to apply the ICMCI competence model to domestic consultants. As a result of the study, it was found that business competency and technical competency had a positive effect on project performance, but values & behavior competency were not statistically significant. On the other hand, it was found that only technical competency, values & behavior competency had a positive effect on social-relational competency. Through this study, it was confirmed that a deep understanding and perception of the consulting business is necessary to grow into a professional consultant, but there is a limit to generalizing the research results because the characteristics of the population cannot be sufficiently reflected with a small sample.

A Study on the Safety Ratio of Reservoir Embankment by Seismic Reinforcement Section Shape (내진보강 단면형상에 따른 국내 저수지 제방의 안전율에 대한 검토)

  • Lim, Seonghun;Kim, Daehyeon
    • The Journal of Engineering Geology
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    • v.31 no.3
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    • pp.343-355
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    • 2021
  • Agricultural reservoirs seek human convenience by supplying agricultural water and providing flood damage effects and rest areas at the same time, but preventing them from aging reservoirs and earthquakes is important. The safety of levees is influenced by field material properties such as soil parameter values of the granular materials that make up the levees, but since precision safety diagnosis or general literature values are diverted, the final safety factors are limited to material properties alone. Since safety factors are determined by physical characteristic values and embankment shapes and have a significant impact on safety factors, accurate contemplation is required when examining reinforced cross sections. Therefore, this study analyzed the case of reasonable and economical reinforcement intersections when designing '◯◯reservoir' in Goheung-geun, Jeollanam-do using the GEP-SLOPE program to enable rational economic design of reinforcement intersections through repeated reviews. As a result of reducing and analyzing the first, second, and third seismic reinforcement of the levees, it was confirmed that the safety ratio was secured even with a significantly smaller amount of reinforcement than the first, second, and lower slopes by obtaining design standards of 1.20. In addition, when determining all seismic reinforcement cross-sectional shapes, it was confirmed that the shape that reinforces only the lower side rather than the upper side of the slope and the entire slope was economical with minimized cross-sectional reinforcement.

A discourse semiotics analysis on Hwang Sun-won's short story "Bulls" (황순원의 단편소설 「황소들」에 대한 담화 기호학적 분석)

  • Hong, Jeong-Pyo
    • 기호학연구
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    • no.56
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    • pp.137-158
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    • 2018
  • In 1999, the French semiotician Jacques Fontanille published his work on discourse semiotics as an attempt to overcome the limitations of structuralism. Discourse semiotics has expanded the realm of semiotics by taking a phenomenological approach that examines the structure of consciousness. Phenomenology pays special attention to the operation of human consciousness, which, instead of staying put, moves from one place to another-unbeknownst to its agent. This paper examines "Bulls" through a phenomenological approach as the short story depicts the stream of consciousness that unfolds within the inner world of Pau, the young male protagonist. The rhetorical approach to literary analysis works at the level of the speech act and directly relates to speech act theory. In rhetorics, figures and tropes are dominated by speech acts. Whereas conventional rhetorical analysis lacks a kinetic perspective as it revolves around flat semantic inspections, the discourse semiotics approach applied in this paper allows for an indepth multidimensional analysis where the analyses of ${\acute{e}}nonc{\acute{e}}$ and ${\acute{e}}nonciation$ complement each other. Presenting a peasant movement to the reader through the eyes of the young male protagonist Pau, "Bulls" is considered a significant literary feat in the history of Korea's New Literature as the work is highly regarded for its impressive depiction of a communal movement. This paper reinterprets and reevaluates the story under a new light, mainly through a rhetorical approach and a phenomenological approach that hinges on discourse semiotics.

Post-Historical Description and Spatial Attribute - Focusing on the Movie Paradise in Service - (탈역사 서술과 공간의 표상 - 영화 <군중낙원>을 중심으로)

  • Jin, Sung Hee
    • Cross-Cultural Studies
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    • v.43
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    • pp.405-428
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    • 2016
  • The purpose of this paper is to examine the narrative-building method and the post-historical descriptive aspects of the movie Paradise in Service, which deals with the modern history of Taiwan. Although Paradise in Service tells the history of a certain time period, it focuses on the anguish and agony felt by people who lived during that age rather than on the meaning of historical events or interpretation of the past in terms of official historical discourse. That is, as it avoids looking at the present by composing a narrative in the descriptive historical context and from bearing weight from the viewpoint of realism, it gains the possibility of establishing a new field of discourse through a post-historical discussion using descriptive historical texts. However, the movie tries to create fantasy through a special type of licensed prostitution as a means of post-historical description. In other words, when this movie tries to reproduce the microscopic history of common people in trouble because of a historical tragedy, it considers only men and excludes "weak" women. Thus, although Paradise in Service has meaning in that it gives an example of how movies can disrupt official historical discourse and group memory and rewrite history by focusing on individuals, it is limited by its male-centrism.

A Study on the Frictional Resistance Chracteristics of Pressurized Soil Nailing Using Rapid Setting Cement (초속경 시멘트를 사용한 가압식 쏘일네일링의 주입시간에 따른 마찰저항특성에 관한 연구)

  • Lee, Arum;Shin, Eunchul;Lee, Chulhee;Rim, Yongkwan
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.4
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    • pp.1-10
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    • 2018
  • Although the soil nailing method is generally used as a gravity grouting, the development and application of pressurized grouting method has recently increased to address the problem of joint generation and filling due to grouting. Pressurized grouting of the soil nailing method is generally used in combination with ordinary portland cement and water. In the field, the cement is mixed with the rapid setting cement to reduce curing time because ordinary portland cement takes more than 10 days to satisfy the required strength. In this study, uniaxial compression tests and laboratory tests were carried out to confirm the efficiency of the grouting material according to the mixing ratio of rapid setting cement. The mixing ratio of 30% grouting satisfies the required strength within 7 days and satisfies the optimum gel time. As a result of the laboratory test with granite weathered soil, the reinforcing effect was confirmed to be 1.5 times as compared with the gravity type at an injection time of 10 seconds and a strain of 15%. The friction resistance increases linearly with the increase of the injection time, but it is confirmed that the friction resistance decreases due to the hydraulic fracturing effect at the injection time exceeding the limit injection pressure. Numerical analysis was performed to compare the stability of slopes not reinforced with slopes reinforced with gravity and pressurized soil nailing.

Effects of Psychological Capital on the Job Performance of Public Enterprise Employees (심리적 자본이 공기업 종사자의 직무수행에 미치는 영향)

  • Kim, Sung-Jong
    • The Journal of the Korea Contents Association
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    • v.19 no.1
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    • pp.293-303
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    • 2019
  • The purpose of this research is to investigate the psychological factors affecting job performance of public enterprise employee. Based on the literature review, three types of job performance are identified, which are behavioral responses to the demands from job environment. They are named as task performance, contextual performance, and adaptive performance. As independent variables, four factors were selected form positive psychological concepts, which are self-efficacy, hope, optimism, and resilience. These are the factors which compose of the concept of psychological capital. All the factors are hypothesized to positively affect job performances. From the regression analysis results, all the psychological factors in the model were turned out to have statistically significant impacts on the job performances. The importance of variable 'resilience' were dominant all three models, which might be interpreted as a behavioral response to the demands from uncertain organizational enviornments. From the marginal effect analysis, contextual performance decreases first five years, then reach peak at 20th. year. These results demonstrates that mid-level employees in the organizational hierarchy are more concerned with the overall performance of organization.

Prediction of Ship Roll Motion using Machine Learning-based Surrogate Model (기계학습기반의 근사모델을 이용한 선박 횡동요 운동 예측)

  • Kim, Young-Rong;Park, Jun-Bum;Moon, Serng-Bae
    • Journal of Navigation and Port Research
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    • v.42 no.6
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    • pp.395-405
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    • 2018
  • Seakeeping safety module in Korean e-Navigation system is one of the ship remote monitoring services that is employed to ensure the safety of ships by monitoring the ship's real time performance and providing a warning in advance when the abnormal conditions are encountered in seakeeping performance. In general, seakeeping performance has been evaluated by simulating ship motion analysis under specific conditions for its design. However, due to restriction of computation time, it is not realistic to perform simulations to evaluate seakeeping performance under real-time operation conditions. This study aims to introduce a reasonable and faster method to predict a ship's roll motion which is one of the factors used to evaluate a ship's seakeeping performance by using a machine learning-based surrogate model. Through the application of various learning techniques and sampling conditions on training data, it was observed that the difference of roll motion between a given surrogate model and motion analysis was within 1%. Therefore, it can be concluded that this method can be useful to evaluate the seakeeping performance of a ship in real-time operation.

Study on Chinese Consumers'Awareness of Korean Grape (한국산 포도의 중국 소비자 인식조사 연구)

  • Woo, Soo Gon;So, Namho;Ko, Hyeon Seok
    • Journal of the Korean Society of International Agriculture
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    • v.30 no.4
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    • pp.320-327
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    • 2018
  • The purpose of this study is to suggest the policy direction for promoting Korean grape, Shine Muscat, export to China. For this, the data were collected from 102 Chinese who live in Guangzhou province. The survey was conducted from Oct 10th to 13th 2017. PLS-SEM model is used to investigate the main factors that cause the Chinese consumers to purchase Korean grape, Shine Muscat. This study finds that the post-evaluation factor is more important to obtain final evaluation and to purchase Korean grape in the future. Thus farmers and research institutes should investigate how to improve the quality for the sweetness and the texture of the grape, reflecting the Chinese consumers' preference.