• 설비공학논문집
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• 제21권7호
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• pp.417-423
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• 2009

Air curtains are widely used for gates of shopping mall, warehouse, cold stores and refrigerated display cabinets. The purpose of the air curtain is to reduce the infiltration of outdoor air and heat loss from the air conditioning space to ambient air. Design data for the air curtain given by previous researchers do not mention the influence of wind speed. Thus, this paper presents a performance of single jet air curtain in heating space when the wind blows toward the opening space of the building. A numerical simulation is used to study the influence of various parameters on the efficiency of the downward-blowing air curtain device which is installed inside of the wall above the door. The performance of the air curtain is evaluated by sealing efficiency which provides the assessment of the energy savings. A new safety factor is also proposed for determination of air curtain jet velocity under the various wind conditions.

• 유통과학연구
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• 제22권5호
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• pp.117-129
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• 2024

Purpose: This research aims to explore the ramifications of job stress on cabin crews within the air service distribution sector, specifically examining its impact on service quality through mediating variables such as job satisfaction and engagement during the pandemic era. Research design, data and methodology: The study is based on a sample size of 312 individuals, exclusively comprising cabin crews employed in the airline industry. Methodologically, Confirmatory Factor Analysis (CFA) and Structural Equation Modeling (SEM) were employed for statistical analysis. Results: The findings reveal that both performance evaluation and job responsibility exerted a significant impact on both job satisfaction and job engagement. Furthermore, job engagement demonstrated a substantial influence on service quality. However, in contrast, factors like unstable employment and the working environment showed no significant impact on either job satisfaction or engagement. Additionally, job satisfaction did not exert a significant influence on service quality. Conclusions: These insights will offer the valuable guidance to the airline industry in preparing for unforeseen external environments that may affect the industry. As the aviation sector navigates the challenges posed by the pandemic, understanding and addressing the intricate relationships among job stress, satisfaction, engagement, and service quality will be crucial for effective industry resilience and adaptation.

• International Journal of Precision Engineering and Manufacturing
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• 제8권1호
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• pp.46-51
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• 2007

Environmental contamination creates shortages of potable water. In such situations, the leakage of water due to breakage or aging of rubber valve seats is a serious problem. Rubber is apt to break when it is placed between two materials that contact each other. One way to avoid water leakage due to rubber damage and breakdown is to replace the rubber with metal, which is currently taking place in water distribution systems. In tribology, a severe form of wear is characterized by local macroscopic material transfer or removal, or by problems with sliding protrusions when two solid surfaces experience relative sliding under load. One of the major problems when metal slides is the occurrence of galling. Experimentally, various conditions influence incipient galling, such as hardness, surface roughness, temperature, load, velocity, and the external environment. This study sought to verify the galling tendencies of metal according to its hardness, surface roughness, load, and sliding velocity, and determine the quantitative effect of each factor on the galling tendencies.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.281-288
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• 2011

Hydraulic hose assemblies deliver a fluid power in various oil pressure equipments such as construction machinery, automobile, aircraft, industrial machinery, machine tools, and machinery for ships, or they are used as pipes in oil pressure circuit. However, as the traditional measure for estimating life under the influence of various external factors incurs hardship in terms of time and expenses, it is essential to take accelerated life test by choosing the factor that suits the usage condition of the test object. The objective of the this study is to propose a acceleration model that takes both temperature and pressure without flexing condition into consideration. The life that is calculated by the equation for evaluating life and the test data show similar slopes as a result of comparing and analyzing the equation for evaluating life that is obtained in this research and the test data, which illustrates that they estimate life similarly, and the proposed equation is proved to be an accelerated life equation that presents the test results.

• 디지털산업정보학회논문지
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• 제7권1호
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• pp.127-141
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• 2011

This paper provides a method to evaluate the competitiveness based on IT innovativeness considering the adoption phase and shows how to apply the method with a case of foreign market in the early-adoptive phase. The proposed method considers a variety of corporate and market characteristics concerned with the technology adoption, and it consists of several internal and external impacting factors that can influence the level of IT diffusion. Main advantage of this method is the ease of its applicability that allows evaluating the innovativeness, regardless of corporate size, industry type, or level of technology adoption. Therefore, it is possible for this method to evaluate the technology competitiveness easily and repeatedly, in terms of IT innovativeness by inter-organizations and inter-nations. For the case analysis, the Mongolian IT market with several Korean IT joint firms is introduced, and final data resulted from an early-adoptive phase case are analyzed.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 2002년도 추계 컨퍼런스: 기업경쟁력 강화를 위한 디지털 컨텐츠 및 정보기술 컨퍼런스
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• pp.3-21
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• 2002

The purpose of this study is to demonstrate individual's mobile Internet acceptance by extending the technology acceptance model (TAM) to the field of the mobile Internet. This research utilized the structural equation model to examine the research model on the mobile Internet use. System quality and information quality as external variables were examined, and playfulness as an intrinsic factor was tested. The research model was successfully validated in the environment of extension model for the mobile internet.

• 한국컴퓨터정보학회논문지
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• 제23권12호
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• pp.195-201
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• 2018

This study is attempted to demonstrate the structure of the influencing factors on the performance of services of knowledge based service firms. In the model presented, the structure is that service performance in knowledge-based services are affected by the strategic utilization of knowledge resources and service orientation factors of the service organization. And the service performance are also affected in which the systemization of service processes and customer satisfaction play a mediating role. As an analysis result of examining 148 practitioners engaged in the knowledge service industry, it is necessary to increase the satisfaction of external customers in order to improve service performance in a knowledge-based service organizations. This can be achieved by increasing the satisfaction of internal customers. In addition, for this structure to be successful, the service production process to be provided to the customer must be enhanced. The service production process has been found to be an important factor influencing the internal customer satisfaction and service delivery process, especially in the use of knowledge resource, and customer oriented service among service orientation factors.

• Kyungpook Mathematical Journal
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• 제60권4호
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• pp.853-867
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• 2020

The aim of this study was to analyze the momentum and heat transfer of a rotating nanofluid with conducting spherical dust particles. The fluid flows over a stretching surface under the influence of an external magnetic field. By applying similarity transformations, the governing partial differential equations were trans-formed into nonlinear coupled ordinary differential equations. These equations were solved with the built-in function bvp4c in MATLAB. Moreover, the effects of the rotation parameter ω, magnetic field parameter M, mass concentration of the dust particles α, and volume fraction of the nano particles 𝜙, on the velocity and temperature profiles of the fluid and dust particles were considered. The results agree well with those in published papers. According to the result the hikes in the rotation parameter ω decrease the local Nusselt number, and the increasing volume fraction of the nano particles 𝜙 increases the local Nusselt number. Moreover the friction factor along the x and y axes increases with increasing volume fraction of the nano particles 𝜙.

• 한국콘텐츠학회논문지
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• 제17권3호
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• pp.1-14
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• 2017

본 연구는 G시의 남, 여 중학교에 재학중인 1, 2, 3학년 546명을 대상으로 정서 행동문제, 부모관계, 교우관계, 교사관계가 등교거부성에 미치는 영향과 그 경로를 파악하기 위하여 Pearson 적률상관분석과 LISREL 프로그램을 이용한 경로분석을 실시하였으며, 본 연구에서 나타난 연구결과는 다음과 같다. 정서 행동문제 중 외현화문제와 교사관계변인 중 사회적지지 요인, 교우관계변인 중 신뢰감요인과 부모관계변인 중 부정적지지요인, 교사관계변인 중 사회적지지요인과 부모관계변인 중 부정적지지 요인을 제외한 모든 관계에서 유의한 상관관계가 있는 것으로 나타났으며, 정서 행동문제는 등교거부성과 부모관계에 매개효과 없이 각각 매우 높은 직접적인 영향을 미치는 것으로 나타났고, 교우관계와 교사관계에는 통계적으로 유의한 직접적인 영향을 미치지는 않고 간접적인 부적영향을 미치는 것으로 나타났다. 또한 교우관계는 등교거부성에 통계적으로 유의한 직접적인 영향을 미치지는 않고 통계적으로 유의한 간접적인 부적영향을 미치는 것으로 나타났으며, 교사관계는 등교거부성에 통계적으로 유의한 직접적인 영향을 미치는 것으로 나타났고, 부모관계는 등교거부성에는 통계적으로 유의한 직접적인 영향을 미치지 못하고 교우관계와 교사관계를 매개로 간접적인 영향을 미치고 있는 것으로 나타났다.

• 한국환경복원기술학회지
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• 제20권1호
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• pp.131-142
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• 2017

The function of urban parks as wildlife habitats is becoming increasingly important. The urban park serves as a key area for preserving urban biodiversity. The purpose of this study is to estimate the bird species diversity in 30 parks in Cheonan city and quantitatively analyze the influence of vegetation, park structure and landscape connectivity index. As the results, a total of 27 birds species and 1,509 individuals were found at the sites and the largest number of birds were found in the Cheongsa park with 17 species. The optimal regression model was selected as the explanatory variables for the logged park area (LPA), the tree cover ratio (Co_T) and the patch betweenness centrality (PB). LPA and Co_T mean the internal characteristics of the park, and PB was the external environmental variable meaning landscape connectivity. LPA was the most important factor (73.3%) as bird habitat, and the PB could be interpreted as a factor that should be considered as important (26.7%). It will be possible to consider these environmental variables in the park and green area construction and management.