• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.463-463
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• 2012

본 연구에서는 유역의 공간적 자기상사성 평가를 통하여 하천유역의 특성을 파악하고자 하였다. 이를 위해 자기상사성 분석의 지표인 허스트지수 및 프랙탈차원을 산정하였다. 허스트지수(h)의 산정은 모형에 있어서 상당히 중요한 부분을 차지한다. 이 지수에 따라 지형의 모양은 서로 상이하게 다루어질 수 있기 때문이다. 허스트지수의 산정은 Hurst가 제시한 방법(허스트지수), Peters의 수정식, Mandebrot와 Wallis의 Pox 도표, 투영면적 및 표면적 비율 방법(면적지수)이 있으며, 본 연구에서는 유역의 공간 자기상성 분석을 위해 면적지수에 의한 방법과 허스트지수에 의한 방법을 적용하였다. 지형자료는 LiDAR 측량 및 하천 횡단측량에 의해 생성된 정밀 DEM을 활용하여 허스트지수 및 프랙탈차원을 산정하였다. 면적지수 및 허스트지수에 의한 프랙탈차원과 평균경사도와의 관계에서 아라천유역은 결정계수 R2값이 94.9 %, 99.5 %로 비교적 결정계수값이 크게 나타났으며, 경사도와 표면적과의 관계에서 결정계수 R2값은 81.8 %로 분석되었다. 이는 면적지수와 허스트지수에 의해 산정된 프랙탈 차원은 유역의 지형특성 인자로 타당성을 갖는 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.30 no.2
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• pp.97-106
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• 1997

Parameters of the Nash model were analyzed using similarity concepts for the hydrogeomorphologic and the time response characteristics, then the application of parameter estimation was performed for a basin where no data are available. The self-similarity was investigated to evaluate the similarity of hydrogeomorphologic characteristics and to derive a equation for the time of concentration. The relation between model parameters and time characteristics such as travel and lag time, were developed to obtain their properties of similarity. There were remarkable results about the assessment for basin similarity and the application to an ungaged basin in Wi stream basin.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.350-363
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• 2016

The purpose of this study was to examine the relationships between emotional intelligence and job performance. Also, the study explore the effects of self-efficacy as a mediating variable and person-supervisor fit as a moderating variable on the mentioned relationships. In order to verify the assumptions related to this research, a survey of 173 sales representatives working in various organizations was conducted. Survey results supported the assumption that higher emotional intelligence resulted in higher job performance. And another assumption that job performance could be predicted more precisely through mediating effect of self-efficacy. Finally, results revealed that the relationships between emotional intelligence and self-efficacy became stronger when the scores of person-supervisor fit were higher. Theoretical and practical implication were reviewed and limitations of the study and suggestions for future research were discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.71-78
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• 2002

Experiments have been performed using two-color PIV in hydrogen non-premixed flames with various conditions of coaxial air, which was classified into three cases with/without reaction. Mean velocity, turbulence intensity and Reynolds stress were analyzed using flow fields from PIV measurement First, the similarity of pure jet had a good agreement with previous results of other researchers. It was found that the decay of centerline velocity was proportional to $x^{-1}$ in coaxial air conditions. By normalizing axial distance with effective jet diameter defined by effective density, the data of centerline velocity collapsed a single line. And the radial profiles of mean velocity showed that they didn't become self-similar because the curves differed from each other as coaxial air velocity increased at fixed fuel velocity. Also, turbulence intensity became self-similar further downstream than mean velocity.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.701-711
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• 2022

This study tried to examine the relationship between superior leadership and emotional support from co-workers on task performance through performance evaluation fairness and self-efficacy in order to find factors that affect the task performance of a company in an uncertain market environment. For this purpose, 500 copies of questionnaire data were collected from corporate employees, and the research hypothesis was verified using Smart PLS 3.0. As a result of the study, superior leadership and emotional support from co-workers showed a positive (+) effect individually on the fairness of employee performance evaluation, Performance evaluation fairness showed a positive (+) effect on self-efficacy. Through this study, it was found that the fairness and self-efficacy of the performance evaluation accepted by employees affects work performance, providing a theoretical foundation for subsequent researchers. Practical implications are suggested to inspire employees to take on a challenge by managing them properly. In future research, based on the results of this study, various studies are needed on the factors that an organization must have for task performance.

• Journal of Korea Water Resources Association
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• v.42 no.9
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• pp.691-702
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• 2009

This study makes a systematic approach to Hack's law considering self-affinity and self-similarity of natural basins as well as the elongation of corresponding catchment-plan forms. Catchment-plan forms extracted from DEM appear to be the population come from the interactions of 2 hypotheses on Hack's law. It is judged that the elongation measures based on inertia moments are more intuitive than the ones based on main channel lengths. The exponent of Hack's law, h, seems to be similar to the result of Gray's study (1961). However Hurst exponent, H, being 0.96 imply that catchment-plan forms considered in this study have isotropic increasing properties with scale. From this point of view it is inferred that the shapes of the basins in this study would be more affected from self-similarity of main channel lengths than self-affinity of catchment-plan forms.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.189-196
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• 2016

The purpose of this study is to investigate the causal relationships among self-efficacy, perceived usefulness, supervisor and peer support, satisfaction, and transfer intentions in the corporate mobile learning. For this study, the web survey was administered to 302 mobile learning learners of the A domestic corporation in South Korea. Structural equation modeling(SEM) analysis was conducted in order to examine the causal relationships among the variables. The results indicated that first, self-efficacy, perceived usefulness, and supervisor and peer support had positive effects on satisfaction. Second, supervisor and peer support and satisfaction had positive effects on transfer intentions. Third, satisfaction mediated the relationship between self-efficacy and perceived usefulness, while it did partially the relationship between supervisor and peer support and transfer intentions. Based on the result of the research, the study proposes organizational environment with cooperative supervisor and peer support should be made in order to improve the level of learners' transfer intentions. In addition, learning strategies that facilitate learners' self-efficacy and mobile information technology acceptance are needed to develop for enhancing the learners' satisfaction.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.427-435
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• 1999

The Clark unit hydrograph is a three parameter synthetic unit hydrograph procedure that can be used in flood hydrology. The present work is an attempt to estimate parameters of the Clark model in ungaged basin by means of relationships that provides for the hydrologic similarity. The time area concentration curve was determined by analytic method and the Clark model was generalized by being made dimensionless form. Calculation of the concentration time was made with the formula fractal concept used, and the storage coefficient was estimated by the empirical and regional equation. Evaluation on Dongok basin was performed to prove the validity of the proposed model. The derived hydrograph predicted the observed hydrograph fairly well.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.565-577
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• 1999

The geometric patterns of a stream network in a drainage basin can be viewed as a "fractal" with fractal dimensions. Fractals provide a mathematical framework for treatment of irregular, ostensively complex shapes that show similar patterns or geometric characteristics over a range of scale. GIUH (Geomorphological Instantaneous Unit Hydrograph) is based on the hydrologic response of surface runoff in a catchment basin. This model incorporates geomorphologic parameters of a basin using Horton's order ratios. For an ordered drainage system, the fractal dimensions can be derived from Horton's laws of stream numbers, stream lengths and stream areas. In this paper, a fractal approach, which is leading to representation of a 2-parameter Gamma distribution type GIUH, has been carried out to incorporate the self similarity of the channel networks based on the high correlations between the Horton's order ratios. The shape and scale parameter of the GIUH-Nash model of IUH in terms of Horton's order ratios of a catchment proposed by Rosso(l984J are simplified by applying the fractal dimension of main stream length and channel network of a river basin. basin.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.489-505
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• 2019

This study is about the impersonal behavior of the supervisor, which is the root cause of 'Workplace Harassment [bullying]', which becomes familiar to Korean workers. For the purpose of the study, characteristics of supervisors are classified into three situations such as personal situation (authoritarian propensity), organizational situation (job insecurity), and personal and organizational situation (self-defensive ambivalence). Then the effects of those propensities on the organizational commitment of their subordinating workers through abusive supervision were analyzed. To this end, separate surveys for team leader and team members were composed. The subjects were male and female workers in large enterprise in Korea. The major results of the study are as follows. First, the three predisposing factors related to the abusive supervision (authoritarianism, job insecurity, and self-defensive ambivalence) made positive (+) effects on the abusive supervision of the supervisor. Second, in the hypothesis 2 regarding the effects of the abusive supervision of the supervisor on the organizational commitment of the subordinates, it was found that the abusive supervision of the supervisor made negative (-) effects on the organizational commitment of the subordinates. Third, in the verification of the hypothesis 3 regarding the mediating effect of the abusive supervision, the three predisposing factors partially mediated the abusive supervision and made negative (-) effects on the organizational commitment of the subordinates.