• Title/Summary/Keyword: Empirical Review

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Estimation of Roughness Coefficient Using a Representative Grain Diameter for Han Stream in Jeju Island (한천의 대표입경을 이용한 조도계수 산정)

  • Lee, Jun-Ho;Yang, Sung-Kee;Kim, Dong-Su
    • Journal of Environmental Science International
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    • v.22 no.5
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    • pp.563-570
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    • 2013
  • Roughness coefficient was computed for review of applicability based on measurement of the representative grain diameter reflecting channel characteristics of Han Stream. After field survey, collection of bed material, and grain analysis on the collected bed material, roughness coefficient was computed using representative grain and existing empirical equation for roughness coefficient. Value of roughness coefficient calculated using equation by Meyer-Peter and Muller (1948) was 0.0417 for upstream, 0.0432 for midstream, and 0.0493 for downstream. As a result of comparing the computed roughness coefficient to other empirical equations for review of applicability, the coefficient was larger in Strickler (1923) equation by 0.006. Smaller coefficient was shown by Planning Report for River Improvement Works. Equation by Garde and Raju (1978) was larger by 0.004, and equations by Lane and Carlson (1953) and by Meyer-Peter and Muller (1948) were larger by 0.001. Such precise roughness coefficient is extremely important when computing the amount of flood in rivers to prevent destruction of downstream embankments and property damages from flooding. Since roughness coefficient is a factor determined by complicated elements and differs according to time and space, continued management of roughness coefficient in rivers and streams is deemed necessary.

An Empirical Study on User's e-Loyalty in Trustworthness of Electronic Trade Service (전자무역 서비스 신뢰성과 이용자의 e-충성도에 대한 실증분석)

  • Shim, Jae-Hee
    • International Commerce and Information Review
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    • v.10 no.3
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    • pp.23-40
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    • 2008
  • Considering rapid development of Electronic Trade in Korea, it is an important issue to analyze consumers' satisfaction and e-loyalty. The purpose of this study is to find the affecting factors on the determinants and utilizable intention of electronic trade trustworthness and e-loyalty. In the literature review, it was made to compare and analyze the precedent papers about electronic trade trustworthness theory, Keller and Aaker(1992), Yun, Seong-jun's(2000) model of the trustworthness. This study investigates the concept of the satisfaction, e-loyalty in electronic trade site and its determinants, and tries to establish e-loyalty analyzing model. The model of the satisfaction, e-loyalty electronic trade site is tested here using data from 106 samples. The major finding of this paper would be summarized as followed : And then it was used the empirical research method to test hypotheses which was established based on the precedent studies : 1) electronic trade factors are positively related to the trustworthness on the electronic trade practical, not being trustworthness of the functionality on electronic trade practical in international trade company. 2) tr stworthness of electronic trade practical is positively related to the e-loyalty in international trade companies.

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Correlations for Prediction of Non-evaporating Diesel Spray Penetration

  • No, Soo-Young
    • Journal of ILASS-Korea
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    • v.12 no.3
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    • pp.146-153
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    • 2007
  • The prediction of diesel spray penetration has been the subject of several works and intensive investigations are still underway by many researchers. It is required to summarize the correlations developed before 1990 days and to introduce the correlations reported recently in the literature. The existing zero-dimensional models for the prediction of diesel fuel spray penetration can be classified as theoretical and empirical correlations. Of various correlations, the models considered in this paper were selected as based on the evaluation results of previous reviews and the recently published works in the literature. The existing theoretical correlations can be classified into seven categories and the existing empirical ones as two categories in this review. According to the review of existing models, the dominating factors for the prediction of spray tip penetration are the spray angle, discharge coefficient, pressure drop across nozzle, ambient density and orifice diameter and time after the start of injection. Especially, the definition for the measurement of spray angle is different with researchers. It is required to evaluate the existing spray tip penetration models for the very high injection pressure and other fuel sprays such as DME. It is also required to evaluate the correlations for the prediction of diesel spray penetration with the connection of liquid-phase penetration.

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A Review on Spray Characteristics of Biobutanol and Its Blended Fuels in IC engines

  • No, Soo-Young
    • Journal of ILASS-Korea
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    • v.21 no.3
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    • pp.144-154
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    • 2016
  • This review will be concentrated on the spray characteristics of biobutanol and its blends fuels in internal combustion engines including compression ignition, spark ignition and gas turbine engines. Butanol can be produced by fermentation from sucrose-containing feedstocks, starchy materials and lignocellulosic biomass. Among four isomers of butanol, n-butanol and iso-butanol has been used in CI and SI engines. This is due to higher octane rating and lower water solubility of both butanol compared with other isomers. The researches on the spray characteristics of neat butanol can be classified into the application to CI and SI engines, particularly GDI engine. Two empirical correlations for the prediction of spray angle for butanol as a function of Reynolds number was newly suggested. However, the applicability for the suggested empirical correlation is not yet proved. The butanol blended fuels used for the investigation of spray characteristics includes butanol-biodiesel blend, butanol-gasoline blend, butano-jet A blend and butanol-other fuel blends. Three blends such as butanol/ethanol, butanol/heptane and butanol/heavy fuel oil blends are included in butanol-other fuel blends. Even though combustion and emission characteristics of butanol/diesel fuel blend in CI engines were broadly investigated, study on spray characteristics of butanol/diesel fuel blend could not be found in the literature. In addition, the more study on the spray characteristics of butanol /gasoline blend is required.

An Empirical Study on the Use of Third Party Logistics in Korean Companies (물류산업 합리화와 제3자 로지스틱스 이용 결정요인분석)

  • Lee Hee-Joon
    • Management & Information Systems Review
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    • v.4
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    • pp.469-500
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    • 2000
  • Over the past decades the concept of Third-Party Logistics(TPL) has generated considerable interest in American and European industries. It involves outsourcing logistics activities that have traditionally been performed within an organization. The functions performed by the third-party logistics can encompass the entire logistics process or, more commonly, selected activities with that process. Increasing corporate emphasis on such concepts as reengineering and supply chain management has led many companies to consider the use of such third-party logistics. This study examines the possibility of applying existing American research of the third-party logistics to Korean companies and investigates the criteria for the use of third-party logistics in Korea. To design the model and generate the hypotheses, this study conducted a comprehensive literature survey on the third-party logistics. To test the hypotheses, this study collected data from 229 companies from the public companies in Korea through a questionnaire survey and conducted descriptive analysis, correlation analysis, factor analysis, and multiple regression analysis using the SPSS for Windows Ver. 7.5 package. This study is hoped that it may contribute to the understanding and introducing of the third-party logistics in the fields of the firms. But there were some restrictions that the respondents were not covered all kinds of firms. These and other major findings from this study imply that existing American studies may be applicable the Korean companies and that this study may complement the deficiencies of the existing studies. Thus, the summary of the literature review, the research model and hypotheses, and empirical findings in this study will provide useful ideas for future research and deep insights for successful logistics management.

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The Moderation Effect of Consumer Involvement in the Relationship between Customer Satisfaction and Loyalty : Focused on the Service Category (고객만족과 고객충성도의 관계에서 소비자 관여도의 조절효과 : 서비스 카테고리를 중심으로)

  • Park, Sang-June;Lee, Yeong-Ran
    • Korean Management Science Review
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    • v.34 no.3
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    • pp.61-77
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    • 2017
  • This study investigates the effect of consumer involvement in the relationship between customer satisfaction and loyalty (which is measured as consumers' repurchase and WOM intentions). Previous research has presented inconsistent implications on the role of consumer involvement in the relationship. Some researchers have presented the empirical results showing that consumer involvement moderates the relationship, whereas others have done the empirical results implying that the consumer involvement does not moderates. In sum, the previous empirical studies have provided the inconsistent empirical results that consumer involvement may be a moderator or a non-moderator in the relationship between customer satisfaction and loyalty. Thus, we start this research with two research questions: "Does consumer involvement has a moderation effect on the relationship between-customer satisfaction and loyalty across various service industries?" and "Can the moderation effect of consumer involvement be detected differently depending on the statistical methods used to probe the moderation effect?" A questionnaire survey was conducted in the context of four service categories: eight service firms for fast food, four firms for family restaurant, four firms for movie theater and four firms for Bakery. Hierarchical regression analyses (moderated regression analyses) and chi-square difference tests were used to identify the role of consumer involvement in the relationship between customer satisfaction and loyalty. The empirical results show that there does not exist the difference in the moderation effects of consumer involvement identified by the two statistical methods (i.e., hierarchical regression analyses vs. chi-square difference tests), however, that there exists the difference in the identified moderation effects of consumer across service categories. In the final section, we summarize the implications and re-interpret the empirical results provided in the previous studies.

An Empirical Study on the Effect of Emotional Intelligence and Logic Intelligence on Organizational Citizenship Behavior - Moderating Effect of Emotional Labor - (감성지능과 논리지능이 조직시민행동에 미치는 영향 - 감정노동의 조절효과 -)

  • Jung, Hyun-Woo
    • Management & Information Systems Review
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    • v.30 no.3
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    • pp.107-132
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    • 2011
  • The purposes of this paper are to examine the effect of emotional intelligence and logic intelligence on organizational citizenship behavior and to examine the moderating effect of intelligence labor on these relationship. For these purposes, literature review and survey research were conducted. The 420 questionnaires were sent to the 12 manufactural firms in the Busan and Kyungsang Nam-Do region for empirical analysis. Total 363 usable responses were collected(effective response rate : 86.40%). The major findings of the empirical research are as follows ; First, emotional intelligence and logic intelligence have positive influence organizational citizenship behavior. but emotional intelligence have more positive influence than logic intelligence on organizational citizenship behavior. Second, emotional intelligence has differential influence on organizational citizenship behavior by emotional labor, but logic intelligence hasn't that. In conclusion, emotional intelligence is expected to improve organizational citizenship behavior which is extra-role behavior in an organization. Therefore, managers have to develop organizational citizenship behavior by exhibiting emotional intelligence, considering emotional labor.

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Current Status and Directions of Professional Identity Formation in Medical Education (전문직 정체성 형성 및 촉진을 위한 의학교육 현황과 고려점)

  • Han, Heeyoung;Suh, Boyung
    • Korean Medical Education Review
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    • v.23 no.2
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    • pp.80-89
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    • 2021
  • Professional identity formation (PIF) is an essential concept in professional education. Many scholars have explored conceptual frameworks of PIF and conducted empirical studies to advance an understanding of the construct in medical education. Despite its importance, it is unclear what educational approaches and assessment practices are actually implemented in medical education settings. Therefore, we conducted a literature review of empirical studies reporting educational practices for medical learners' PIF. We searched the Web of Science database using keywords and chose 37 papers for analysis based on inclusion and exclusion criteria. Thematic analysis was conducted. Most empirical papers (92%) were from North America and Western Europe and used qualitative research methods, including mixed methods (99%). The papers reported the use of reflection activities and elective courses for specific purposes, such as art as an educational activity. Patient and healthcare experiences were also found to be a central theme in medical learners' PIF. Through an iterative analysis of the key themes that emerged from the PIF studies, we derived the following key concepts and implications: (1) the importance of creating informal and incidental learning environments, (2) ordinary yet authentic patient experiences, (3) a climate of psychosocial safety in a learning environment embracing individual learners' background and emotional development, and (4) the reconceptualization of PIF education and assessment. In conclusion, research on PIF should be diversified to include various cultural and social contexts. Theoretical frameworks should also be diversified and developed beyond Kegan's developmental framework to accommodate the nonlinear and dynamic nature of PIF.

Development of roadheader performance prediction model and review of machine specification (로드헤더 장비사양 검토 및 굴착효율 예측 모델 개발)

  • Jae Hoon Jung;Ju Hyi Yim;Jae Won Lee;Han Byul Kang;Do Hoon Kim;Young Jin Shin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.3
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    • pp.221-243
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    • 2023
  • The use of roadheaders has been increasing to mitigate the problems of noise and vibration during tunneling operations in urban area. Since lack of experience of roadheader for hard rock, the selection of appropriate machines and the evaluation of cutting rates have been challenging. Currently, empirical models developed overseas are commonly used to evaluate cutting rates, but their effectiveness has not been verified for domestic rocks. In this paper, a comprehensive literature review was conducted to assess the rock cutting force, cutterhead capacity, and cutting rate to select the appropriate machine and evaluate its performance. The cutterhead capacity was reviewed based on the literature results for the site. Furthermore, a new empirical model and simplified method for predicting cutting rates were proposed through data analysis in relation to operation time and rock strength, and compared with those of the conventional model from the manufacturer. The results show good agreement for high strength range upper 80 MPa of uniaxial compressive strength.

An Empirical Study on the Execution Factors Affecting on Corporate Performance in the Global Electronic Commerce (해외 역직구의 핵심역량이 기업성과에 미치는 영향에 관한 실증연구)

  • Kim, Chang-Bong;Min, Cheol-Hong
    • Korea Trade Review
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    • v.43 no.4
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    • pp.219-245
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    • 2018
  • Recently Korea affected by the US and China trade wars, has been stagnant in the global trade market. However, the global e-commerce market is growing and emerging with new trade opportunity. The purpose of this study is to derive factors of the execution of cross border electronic commerce in the global e-commerce market and to grasp the effects of these factors on firm performance and ultimately to provide policy implications for export expansion. For this purpose, we conducted a literature review to derive the factors for firm performance in the global e-commerce market. Subsequently, conceptual research model and research hypotheses were estabilished, and empirical analysis was conducted through questionnaires. As a result of the empirical analysis, trust and ICT capability have a positive effect on firm performance, and the impact of trust on firm performance depends on the level of dispute settlement. However, ICT capability does not affect firm performance. This study differs from previous studies in that it considered global e-commerce from the perspective of the enterprise and examined factors for firm performance.

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