• 전력전자학회논문지
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• 제6권1호
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• pp.107-113
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• 2001

본 논문에서는 3-레벨 PWM 인버터식 STATCOM의 동특성 해석과 직류측 상.하단 캐패시터 전압의 분균등을 보상하기 위한 제어 시스템을 설계하여 시뮬레이션과 축소모형 실험에 의한 성능 해석에 관하여 기술하였다. STATCOM과 전력 계통을 등가회로로 표현하여 회로 방정식을 유도하고 수리모형을 도출하여 전체 회로의 동적 특성을 분석하고, 고안된 제어 시스템의 성능해석은 Marlab을 이용한 시뮬에리션과 축소모형 실험을 통해 검증하였는데, 검증결과 고안된 제어시스템은 무효전력 보상과 직류측 상.하단 캐패시터 전압의 불균등을 해소하는 우수한 성능을 갖는 것을 확인하였다.

• 대한산업공학회지
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• 제39권3호
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• pp.198-203
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• 2013

Industry convergence is the inexorable trend, which has become a fundamental concept to understand the industrial dynamics and to develop business strategies. However, most of the previous studies on convergence have dealt with the issues at the macro-level (technology- or industry-level), little attention has been paid to the analysis of convergence at the micro level (firm-level). Recognizing that firms are the principal agents that develop fusion technologies, it is encouraged to help firms to work together for technology convergence. Therefore, this research proposes a collaboration model for SMEs, since SMEs tend to have novel ideas and are flexible enough to make fusion-technology. To do this, we conducted a survey for Korean SMEs and analyzed their successful cases of collaboration, which was used as a basis to develop the model. The research results will help develop strategy or policy to promote the collaboration between SMEs and ultimately to make a fusion-technology.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.285-291
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• 2022

WSN is the major component for information transfer in IoT environments. Source Location Privacy (SLP) has attracted attention in WSN environments. Effective SLP can avoid adversaries to backtrack and capture source nodes. This work presents a Two-Level Randomized Sector-based Routing (TLRSR) model to ensure SLP in wireless environments. Sector creation is the initial process, where the nodes in the network are grouped into defined sectors. The first level routing process identifies sector-based route to the destination node, which is performed by Ant Colony Optimization (ACO). The second level performs route extraction, which identifies the actual nodes for transmission. The route extraction is randomized and is performed using Simulated Annealing. This process is distributed between the nodes, hence ensures even charge depletion across the network. Randomized node selection process ensures SLP and also avoids depletion of certain specific nodes, resulting in increased network lifetime. Experiments and comparisons indicate faster route detection and optimal paths by the TLRSR model.

• Nutrition Research and Practice
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• 제5권3호
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• pp.236-245
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• 2011

This study investigated the correlation between consumption of sugar intake by fifth grade students in primary schools and development of Attention Deficit Hyperactivity Disorder (ADHD). A total of 107 students participated, and eight boys and one girl (8.4% of the total) categorized as high risk for ADHD according to diagnostic criteria. There were significant differences in the occupations and drinking habits of the respondents' fathers between the normal group and risk group. In a comparison of students' nutrition intake status with daily nutrition intake standards for Koreans, students consumed twice as much protein as the recommended level, whereas their calcium intake was only 60% of the recommended DRI (dietary reference intake). Regarding intake volume of vitamin C, the normal group posted 143.9% of the recommended DRI, whereas the risk group showed only 65.5% of the recommended DRI. In terms of simple sugar intake from snacks, students in the normal group consumed 58.4 g while the risk group consumed 50.2 g. These levels constituted 12.5% of their total daily volume of sugar intake from snacks, which is higher than the 10% standard recommended by the WHO. In conclusion, children who consumed less sugar from fruit snacks or whose vitamin C intake was less than RI was at increased risks for ADHD (P < 0.05). However, no significant association was observed between total volume of simple sugar intake from snacks and ADHD development.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.973-976
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• 2006

The oscillations of the Caspian Sea level represent a result of mutually related hydrometeorological processes. The change in the tendency of the mean sea level variations that occurred in the middle 1970s, when the long-term level fall was replaced by its rapid and significant rise, represents an important indicator of the changes in the natural regime of the Caspian Sea. Therefore, sea level monitoring and long-term forecast of the sea level changes represent an extremely important task. The aim of this presentation is to show the experience of application of satellite altimetry methods to the investigation of seasonal and interannual variability of the sea level, wind speed and wave height, water dynamics, as well as of uplift of the Earth’s crust in different parts of the Caspian Sea and Kara-Bogaz-Gol Bay. Special attention is given to estimates of the Volga River runoff derived from satellite altimetry data. The work is based on the 1992-2005 TOPEX/Poseidon (T/P) and Jason-1 (J-1) data sets.

• 한국음향학회지
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• 제39권5호
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• pp.497-504
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• 2020

화자 검증에서 화자 임베딩 구축은 중요한 이슈이다. 일반적으로, 화자 임베딩 인코딩을 위해 자기주의 메커니즘이 적용되어졌다. 이전의 연구는 마지막 풀링 계층과 같은 높은 수준의 계층에서 자기 주의를 학습시키는 데 중점을 두었다. 이 경우, 화자 임베딩 인코딩 시 낮은 수준의 계층의 영향이 감소한다는 단점이 있다. 본 연구에서는 잔차 네트워크를 사용하여 Masked Cross Self-Attentive Encoding(MCSAE)를 제안한다. 이는 높은 수준 및 낮은 수준 계층의 특징 학습에 중점을 둔다. 다중 계층 집합을 기반으로 각 잔차 계층의 출력 특징들이 MCSAE에 사용된다. MCSAE에서 교차 자기 주의 모듈에 의해 각 입력 특징의 상호 의존성이 학습된다. 또한 랜덤 마스킹 정규화 모듈은 오버 피팅 문제를 방지하기 위해 적용된다. MCSAE는 화자 정보를 나타내는 프레임의 가중치를 향상시킨다. 그런 다음 출력 특징들이 합쳐져 화자 임베딩으로 인코딩된다. 따라서 MCSAE를 사용하여 보다 유용한 화자 임베딩이 인코딩된다. 실험 결과, VoxCeleb1 평가 데이터 세트를 사용하여 2.63 %의 동일 오류율를 보였다. 이는 이전의 자기 주의 인코딩 및 다른 최신 방법들과 비교하여 성능이 향상되었다.

• 한국안전학회지
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• 제33권2호
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• pp.132-137
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• 2018

Compared with general rivers, fluctuations of the water level and the river bed are severe in the tidal river. In hydro-dynamic aspect, such fluctuation gives different river-bed data to us according to observing period. The time-dependent river-bed data and pre-estimation of the Manning's roughness coefficient which is the key factor of numerical modelling induces uncertainty of evaluating the design flood level. Thus it is necessary to pay more attention to calculate the flood level at tidal rivers than at general rivers. In this study, downstream of the Imjin River where is affected by tide of the West Sea selected as a study site. From the numerical modelling, it was shown that the unsteady simulation gave considerable mitigation of the water level from the starting point to 15 km upstream compared to the steady simulation. Either making a detention pond or optional dredging was not effective to mitigate the flood level at Gugok - Majung region where is located in the downstream of the Imjin River. Therefore, a more sophisticated approach is required to evaluate the design flood level estimation before constructive measures adopted in general rivers when establishing the flood control plan in a tidal river.

• 대한임상독성학회지
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• 제13권2호
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• pp.55-61
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• 2015

Purpose: Many studies have examined the mechanisms of impaired glucose homeostasis after organophosphate (OP) exposure, however no study has evaluated the clinical utility of blood glucose measurements in patients with OP poisoning. The current study was conducted to evaluate the initial glucose level at presentation and the glycemic variables during the first 3 days after admission as a predictor of mortality. Methods: This retrospective observational case series included 228 patients with a history of OP poisoning. Among other clinical data, information on the initial glucose level at presentation and mean glucose level, delta glucose level, and the presence of a hypoglycemic event during the first 3 days of admission, was collected. Results: Survivors had lower initial glucose levels at presentation and glucose variability during the first 3 days of admission compared to non-survivors. The frequency of hypoglycemic events was higher in non-survivors. In multivariate analysis, the initial glucose level (> 233 mg/dl) was an independent predictor of mortality, along with age. Conclusion: The initial glucose level at presentation can be helpful in prediction of mortality in cases of OP intoxication at bedside. The physician should pay attention to patients with a glucose level >233 mg/dl at presentation after ingestion of OP.

• 대한음성학회지:말소리
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• 제59호
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• pp.27-51
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• 2006

For speech recognition systems, rejection function as well as decoding function is necessary to improve the reliability. There have been many research efforts on out-of-vocabulary word rejection, however, little attention has been paid on non-target sentence rejection. Recently pronunciation approaches using speech recognition increase the need for non-target sentence rejection to provide more accurate and robust results. In this paper, we proposed filler model method and word/phoneme detection ratio method to implement non-target sentence rejection system. We made performance evaluation of filler model along to word-level, phoneme-level, and sentence-level filler models respectively. We also perform the similar experiment using word-level and phoneme-level word/phoneme detection ratio method. For the performance evaluation, the minimized average of FAR and FRR is used for comparing the effectiveness of each method along with the number of words of given sentences. From the experimental results, we got to know that word-level method outperforms the other methods, and word-level filler mode shows slightly better results than that of word detection ratio method.

• 보건행정학회지
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• 제29권4호
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• pp.422-430
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• 2019

Background: This study aimed to demonstrate the association between the education level of parents and adolescent depression feeling. Methods: We used the chi-square test and the multiple logistic regression model to analyze the data of the "Korean Youth Health Behavior Survey in 2018" (n=43,220) conducted by the Korea Centers for Disease Control and Prevention. Results: As a result of the analysis, a group whose parents' education level is 'above the university graduation (including the graduation of the college)' had statistically significant experience of depression than a group whose parents' education level is 'high school graduation.' Conclusion: When preparing a policy on adolescent depression feeling, we need to consider the association between the education level of parents and adolescent depression feeling. Especially, a higher level of education of parents needs attention and management to foster positive mental health rather than excessive academic pressure, especially in the parent-child relationship of the same gender.