• Journal of Power Electronics
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• 제10권2호
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• pp.194-202
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• 2010

The main cause of degradation in an unbalanced stand-alone doubly-fed induction generator (DFIG) system is negative sequence components that exist in the generated stator voltages. To eliminate these components, a hybrid current controller composed of a proportional-integral controller and a resonant regulator is developed in this paper. The proposed controller is applied to the rotor-side converter of a DFIG system for the purpose of compensating the negative stator voltage sequences. The proposed current controller is implemented in a single positive rotating reference frame and therefore the controller can directly regulate both the positive and negative sequence components without the need for sequential decomposition of the measured rotor currents. In terms of compensation capability and accuracy, simulations and experimental results demonstrated the excellent performance of the proposed control method when compared to conventional vector control schemes.

• 한국시스템다이내믹스연구
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• 제1권2호
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• pp.33-60
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• 2000

This study aims to conceptually identify the circular causal-relationship which is structured between downsizing and technological innovation in organization. First, through the literature review concerning downsizing and (technological) innovations, we have outlined the conceptual building blocks and research boundaries in this field. Second, we used system thinking method to accomplish our research purpose. The research findings are as follows. First, the promotion of financial resources by downsizing have trade-off relations that have negative of effects in short terms, but positive effects in long time. Second, workforce reduction by downsizing usually has negative influence on employees. Third, capital reduction by downsizing generates not only the climates of cost-cut but also the fact that although the climates may increase economic performance in short terms, it may interrupt technological innovations in long terms. In conclusion, this theses suggests that the relationship of downsizing and technological innovations have complex causal and feedback structures. Therefore, the results of this thesis propose that the argument or practices of downsizing with partial emphasis is very dangerous. Finally some limitations are also discussed.

• 동아시아식생활학회지
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• 제16권1호
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• pp.1-12
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• 2006

This study examine the relationship between the intake of food conformable to each Sasang constitution and the recognition of irregular symptoms of health condition. The study subjects were 362 university students nationwide, classified by heir Sasang constitution. In terms of the intakes of conformable food and the symptom recognition, the number of multiple subjective symptoms tended to rise as the Soeum type digested the conformable food. As for the kinds of food, the Soyang type showed a significant positive correlation between the intake of cucumber namul and the symptoms of eyes and skin, but a negative correlation between the intake of Chongak Kimchi and the symptoms of the digestive system The Soeum type showed a significant positive correlation between multiple subjective symptoms and the intake of Gatkimchi, fernbrake namul, naeng-i soup, naeng-i namul, Korean leek Kimchi, crown daisy namul, and curled mallow soup, a significant positive correlation between the symptom recognition of the respiratory system and the intake of fried flatfish, and chicken gomtang but a negative correlation between the symptom recognition of the eye and skin and the intake of boiled eel. The Taeum type presented the a sigmificant positive correlation between multiple subjective symptoms and the intake of spaghetti, a positive correlation between the symptoms of the respiratory system and the intake of tuna salad, a positive correlation between the symptoms of the eye and skin and the intake of mafa tofu, spaghetti, and tuna salad, a negative correlation between the symptoms of the mouth and anus and the intake of codfish jiri, and a negative correlation between the symptoms of the respiratory system and the intake of tuna salad.

• 대한간호학회지
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• 제38권5호
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• pp.748-757
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• 2008

Purpose: This correlational study was performed to identify the impacts of maternal child rearing attitudes on the menstrual attitudes and the determinants of positive menstrual attitudes in female middle school students. Methods: With convenience sampling, 198 middle school female students were recruited living in one major city and its surrounding areas in Korea. Data was collected using a self administered questionnaire including menstrual attitudes and maternal child rearing attitudes from April 1 to July 15, 2008. Results: Among the Maternal child rearing attitudes, affectionate, achievement oriented and rational attitudes had positive correlations to a positive menstrual attitude, and an autonomous attitude had a negative correlation to a negative menstrual attitude. As determinants of positive menstrual attitudes, feeling of menarche, mother's response at first menstruation, and rational maternal child rearing attitudes were delineated and their explained variance for a positive menstrual attitude was 18.5%. There was no difference on menstrual attitudes by K clustering in terms of maternal child rearing attitudes. Conclusion: These results support the critical role of the mother. Especially desirable maternal child rearing attitudes in relation to a positive menstrual attitude would be affectionate, achievement oriented and rational for early adolescent girls. In further studies, considerations are needed for menstruation related education and research for early adolescents and active involvement of the mother & daughter together.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.353-365
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• 2020

In the previous studies, the authors proposed the use of laminated veneer lumber - carbon fiber reinforced polymer (LVL-CFRP) composite beams for structural application. Bond strength of the LVL-to-CFRP interface and flexural strengthening schemes to increase the bending capacity subjected to positive and negative moment were discussed in the previous works. In this article, theoretical models are proposed to predict the moment capacity when the LVL-CFRP beams are subjected to negative moment. Two common failure modes - CFRP fracture and debonding of CFRP are considered. The non-linear model proposed for positive moment is modified for negative moment to determine the section moment capacity. For the debonding based failure, previously developed bond strength model for CFRP-to-LVL interface is implemented. The theoretical models are validated against the experimental results and then use to determine the moment-rotation behaviour and rotational rigidity to compare the efficacy of various strengthening techniques. It is found that combined use of bi- and uni-directional CFRP U-wrap at the joint performs well in terms of both moment capacity and rotational rigidity.

• 산경연구논집
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• 제14권8호
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• pp.27-35
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• 2023

The main objective of this study is to examine the impact of entrepreneurial orientation (EO) on small and medium-sized enterprises' (SMEs) performance in the context of subcontracting buyer-supplier relation. Specifically, we seek to examine whether the power dynamics between buyer and supplier either support or hamper subcontracting SMEs' ability to effectively pursue EO for enhancing their performance. Research design, data, and methodology: We collected survey questionnaires from Korean SMEs that are certified with Inno-biz by the Korean Ministry of SMEs and Startups. The collected data was analyzed using SPSS 26 and AMOS to create an integrated model. Result: Based on the analysis, our findings indicate that the proactiveness and innovativeness dimensions of EO have a positive effect on the SMEs' performance. However, the risk-taking dimension of EO has a negative effect on performance. Additionally, buyer dependency exhibit both positive and negative moderating effects on different dimensions of EO. Conclusion: For SMEs that rely heavily on a particular buyer in terms of sale, pursuing innovativeness dimension of EO could lead to positive performance, while pursuing proactiveness dimension of EO had a negative moderating effect on performance.

• 아동학회지
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• 제33권1호
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• pp.63-80
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• 2012

The purpose of this study was to analyze the effects of stress perception and social support on subjective well-being according to differing levels of optimism. The participants in this study were 230 pre-service early childhood teachers, majoring in early childhood education at two universities located in Daegu, Gyeongbuk province. The results of this study could be summarized as follows. First, pre-service early childhood teachers were shown to be more optimistic, be more satisfied with life, and had higher positive emotion rates than average. They also showed lower stress perception and negative emotion rates than average. Second, the highly optimistic group showed higher levels than the less optimistic group in terms of both satisfaction with life and positive emotions. Third, the stress perception in both the highly optimistic group and the less optimistic group had an impact on their satisfaction with life, positive emotions, and negative emotions. The degree of peer support perceived by the highly optimistic group showed an impact on satisfaction with life and negative emotions, whereas the degree of parental support perceived by the less optimistic group showed an impact on their levels of satisfaction with life.

• Asian Pacific Journal of Cancer Prevention
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• 제15권14호
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• pp.5539-5544
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• 2014

Background: To evaluate the location of tumor relapse and imaging modality for detection according to the breast cancer subtype: luminal A, luminal B, HER2 positive luminal B, nonluminal HER2 positive, and triple negative. Materials and Methods: A total of 1244 patients with breast cancer with known estrogen receptor (ER), progesterone receptor (PR), Ki-67 and human epidermal growth factor receptor 2 (HER2), who underwent breast surgery from 2009 to 2012 were analyzed. Patients were classified into the following categories: luminal A (n=458), luminal B (n=241), HER2 positive luminal B (n=227), nonluminal HER2 positive (n=145) and triple negative (n=173). A total of 105 cases of relapse were detected in 102 patients: locoregional recurrence (n=46), recurrence in the contralateral breast (n=28) and distant metastasis (n=31). Comparison of proportions was used to determine the difference between subtypes. Results: Relapse rates by subtypes are as follows: luminal A 23 of 458 (5.02%), luminal B 19 of 241(7.88%), HER2 positive luminal B 15 of 227 (6.61%), nonluminal HER2 postive 19 of 145 (13.10%) and triple negative 29 of 173(16.76%). Luminal A tumors had the lowest rate of recurrence and had significantly lower recurrence rate in comparison with nonluminal HER2 postive (p=0.0017) and triple negative subtypes (p<0.0001). Compared with all other subtypes except nonluminal HER2 positive, triple negative tumors had the highest rate of tumor recurrence (p<0.01). Triple negatives were most likely to develop contralateral recurrence against all subtypes (p<0.05). Detection rate of locoregional and contralateral tumor recurrence were 28.3% on mammography (n=17/60). Conclusions: Luminal A tumors are associated with a low risk of recurrence while triple negative lesions have a high risk. In case of triple negative tumors, the contralateral breast has much more recurrence as compared with all other subtype. In terms of detection rates, breast USG was the best modality for detecting tumor recurrence, compared with other modalities (p<0.05). Subtyping of breast tumors using a molecular gene expression panel can identify patients who have increased risk of recurrence and allow prediction of locations of tumor recurrence for each subtype.

• 한국정보통신학회논문지
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• 제19권7호
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• pp.1593-1598
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• 2015

본 논문에서는 사회적 감성과 주가의 상관성을 분석한다. 먼저, 주가 폭락 또는 폭등 기간과 그 직전의 극성을 각각 분석하고 이 결과를 이용하여 사회적 감성과 주가 사이의 상관관계를 분석한다. 본 연구를 위하여 과거의 다우존스산업평균지수 데이터를 수집하고 주가의 폭등과 폭락 시점을 검출한다. 검출한 시점에 근거하여 뉴욕 타임즈 기사를 수집하고 극성을 분석한다. 분석 결과에 의하면 주가 폭락 기간보다 폭등 기간에는 부정적 용어의 출현 빈도가 감소하고 긍정적 용어의 출현 빈도가 증가한다. 주가 폭락 또는 폭등 직전에는 부정적 용어의 출현 빈도와 긍정적 용어의 출현 빈도 사이에 차이가 커지 않다. 상관관계 분석에 의하면, 주가 폭락과 폭등 기간에는 사회적 감성과 주가 사이에 양의 상관관계를 보인다. 반면에, 주가 폭락과 폭등 직전에는 사회적 감성과 주가 사이에 유의한 수준의 상관관계를 나타내지 않는다.

• 한국군사과학기술학회지
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• 제15권2호
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• pp.121-129
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• 2012

In this study, in terms of the exercise vehicles of the weapon systems having negative buoyancy, the analysis on the operation concepts was performed and the new methods of floating to surface were proposed. In case of having negative buoyancy, the additional methods for recovering the exercise vehicle have to be considered. As parts of recovering the exercise vehicle, for floating to surface the new methods of weight discharge, weight separation and sea water discharge were proposed. The conceptual design about sea water discharge method was performed. It was confirmed that those methods could be applied to the design of the exercise vehicle having negative buoyancy.