• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.428-437
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• 2007

The potential for humic substances to serve as terminal electron acceptors in microbial respiration and the effects of humic substances on microbial azoreduction were investigated. The dissimilatory azoreducing microorganism Shewanella decolorationis S12 was able to conserve energy to support growth from electron transport to humics coupled to the oxidation of various organic substances or $H_2$. Batch experiments suggested that when the concentration of anthraquinone-2-sulfonate (AQS), a humics analog, was lower than 3 mmol/l, azoreduction of strain S12 was accelerated under anaerobic condition. However, there was obvious inhibition to azoreduction when the concentration of the AQS was higher than 5 mmol/l. Another humics analog, anthraquinone-2-sulfonate (AQDS), could still prominently accelerate azoreduction, even when the concentration was up to 12 mmol/l, but the rate of acceleration gradually decreased with the increasing concentration of the AQDS. Toxic experiments revealed that AQS can inhibit growth of strain S12 if the concentration past a critical one, but AQDS had no effect on the metabolism and growth of strain S12 although the concentration was up to 20 mmol/l. These results demonstrated that a low concentration of humic substances not only could serve as the terminal electron acceptors for conserving energy for growth, but also act as redox mediator shuttling electrons for the anaerobic azoreduction by S. decolorationis S12. However, a high concentration of humic substances could inhibit the bacterial azoreduction, resulting on the one hand from the toxic effect on cell metabolism and growth, and on the other hand from competion with azo dyes for electrons as electron acceptor.

• 사회복지연구
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• 제37호
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• pp.295-318
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• 2008

본 연구의 목적은 일반긴장이론에 근거한 청소년 지위비행 설명 모형을 검증하는 데 있다. 설문은 2007년 10월 22일부터 2007년 11월 9일까지 서울 및 경기 지역의 중고등학교 남녀청소년을 대상으로 이루어졌다. 본 연구에서는 최종 수거된 1167사례 중 응답내용이 부실한 27사례를 제외하고 총 1140사례를 이용하여 분석하였다. 우울을 매개로한 자녀학대경험과 청소년 지위비행 모형을 구조방정식을 이용하여 분석한 결과 적합도지수가 각각 .986(TLI), .994(CFI), 그리고 .032(RMSEA)으로 나타나 높은 적합도지수를 보여주었다. Aroian test를 통해 우울의 매개효과를 검증한 결과 유의미한 매개효과를 지니고 있음이 검증되었다(p<.001). 그러나 본 연구에서 주요 조건변수로 제시한 청소년의 자기통제력은 우울이 지위비행으로 이르는 경로에 유의미한 영향을 주지 않는 것으로 나타나 조건효과가 검증되지 않았다.

• 한국컴퓨터정보학회논문지
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• 제23권11호
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• pp.229-238
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• 2018

The purpose of this study is to investigate the mediating effect of learners' learning flow in the effect of presence on academic achievement in web-based e-learning. For this purpose, this study analyzed the influencing relationship between the each factor based on the structural model with the learning flow as a mediator variable. Based on existing theoretical studies, learning satisfaction and academic achievement, which represent learning outcomes, are set as dependent variables, and teaching presence, cognitive presence, and social presence are set as independent variables. Data collected from a total of 256 e-learning learners were used in the analysis of this study. According to the results of the analysis, teaching presence, cognitive presence, and social presence were found to have a significant effect on academic achievement when a learning flow is a mediator variable. Concretely, teaching presence, cognitive presence, and social presence have a positive effect on the learning flow, while learning flow has a positive effect on learning satisfaction. On the other hand, learning flow has a negative effect on academic achievement. As a result of verifying the mediating effect of learning flow on the relationship between presence, learning satisfaction, and academic achievement, there was meditating effect in the aggregate. This study implies that in order to increase the level of learning satisfaction and academic achievement, it is necessary to make the teaching-learning design in the provision of contents and materials for e-learning so that the learner can feel the presence. The results of this study can be used as a basic data for seeking support and promotion strategies for enhancement of future learning flow and presence.

• 아동학회지
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• 제27권5호
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• pp.143-157
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• 2006

This study examined the mediating roles of parent and peer attachment in the relationship between academic stress and suicidal impulse among Korean adolescents. The 2959 ninth grade students in this study were selected from among 3211 students(excluding missing cases) who participated in the Korean Youth Panel Study. Following Baron & Kenny's(1986) suggestion, the mediator model was employed to analyze parent and peer attachment. Results showed that academic stress had a significant relationship with adolescent's suicidal impulse. Parent attachment acted as a partial mediator between academic stress and suicidal impulse; that is parent attachment provided a protective mechanism minimizing the direct effects of academic stress. However, peer attachment had no significant relationship with academic stress.

• 품질경영학회지
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• 제45권2호
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• pp.275-292
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• 2017

Purpose: This study is designed to explore web-site service quality factors in job information site for high quality human resource, and to test relationship among web service quality, image, user satisfaction, relationship quality, and loyalty intention. Methods: A survey tool was questionnaire that had obtained validity and reliability through literature survey and pretest survey, and sample 214 was analyzed through SEM using SPSS21.0 and AMOS21.0. Results: Web design and information offer affect Image and user satisfaction. Also, relationship quality turned out to be an important mediator between image and loyalty intention and between customer satisfaction and loyalty intention. Conclusion: This study shows that two factors in via of relationship quality, were important factors that related companies have to emphasize to raise performance, Also, in order to raise loyalty intention of customer, marketer should exert to well manage relationship quality having significance as a mediator.

• 한국생활과학회지
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• 제16권2호
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• pp.433-442
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• 2007

The purpose of this study was to examine the mediating role of attitude, subjective norm, and perceived behavioral control on the relationships between past behavior and customers' intention to engage in exit of dissatisfaction responses. Results of the study demonstrated that the past behavior significantly improved the predictability of the voice of dissatisfaction response intentions. Furthermore, the mediating analyses indicated that the influence of past behavior was mediated by mediator. In the contests of exit behavior, the effect of past behavior on intention to exit was mediated by attitude, subjective norm and perceived behavioral control.

• 대한간호학회지
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• 제38권4호
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• pp.603-611
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• 2008

Purpose: This study was to determine the mediator or moderator role of empowerment in the relationship between the head nurse's transformational leadership and organizational commitment as perceived by staff nurses. Methods: Data was collected from 451 nurses in a tertiary hospital located in B city by means of structured questionnaires. Data was analyzed with descriptive statistics, Pearson's correlation coefficient and hierarchial multiple regression using the SPSS program. Results: Empowerment showed mediating effects between the head nurse's transformational leadership and organizational commitment as perceived by staff nurses. However, empowerment did not show moderating effects. Conclusion: Nurses' perception of empowerment, the head nurse's transformational leadership and organizational commitment have a strong relationship. This finding suggests the importance of empowering nurses to increase organizational commitment.

• 동아시아식생활학회지
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• 제16권5호
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• pp.615-622
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• 2006

The purpose of this study was to examine the mediating role of attitude, subjective norm, and perceived behavioral control on the relationships between past behavior and customers' intention to engage in negative word-of-mouth communication of dissatisfaction responses. Results of the study demonstrated that the inclusion of past behavior improved the predictability of the negative word-of-mouth communication of dissatisfaction response intentions. Furthermore, the mediating analyses indicated that the influence of past behavior was mediated by the mediator. In the contests of negative word-of-mouth communication, the effect of past behavior on intention was partially mediated by attitude, subjective norm and perceived behavioral control.

• 수산해양교육연구
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• 제28권2호
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• pp.550-563
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• 2016

This study examined well-being as a mediator between self-discrepancy and dropout intention of junior college Student. 270 students in Busan answered the questionnaire about self-discrepancy, well-being, dropout intention. Structural equation modeling indicated that there were the complete mediating effect of well-being in the relationship between self-discrepancy and dropout intention. It indicated discrepancy between individuals' representation of their actual self(their actual self-state) and their representation of individual's hopes and aspirations(their ideal self-guide) affects junior college students' dropout intention, and well-being mediate process of self-discrepancy leading to dropout intention. This conclusion provide the significant implications that help preparing psychosocial intervention strategy for junior college students to decrease dropout intention and intervention strategy to enhance their well-being.

• 한국식생활문화학회지
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• 제21권5호
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• pp.500-506
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• 2006

The purpose of this study was to examine the mediating role of attitude, subjective norm, and perceived behavioral control on the relationships between past behavior and customers' intention to engage in voice of dissatisfaction responses. Results of the study demonstrated that the inclusion of past behavior improved the predictability of the voice of dissatisfaction response intentions. Furthermore, the mediating analyses indicated that the influence of past behavior was mediated by mediator. In the contests of voice behavior, the effect of past behavior on intention was not mediated by attitude and perceived behavioral control. Meanwhile, subjective norm mediated the relationship between past behavior and the intention to engage in voice behavior.