• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.697-700
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• 2003

The SASW method is a promising and effective way of profiling ground stiffness nondestructively. This method has been successfully applied to many geotechnical sites, but significant lateral variability, embedded obstacles, and pavement lead to the low reliability. To improve these problems, the horizontal wave component has been introduced to improve the reliability of the stiffness profile determined by the SASW method. To understand dispersion character of the horizontal component wave propagation in artificial profiles, FEM analysis had been performed. Used models are homogeneous half-space and two layered half- spaced layers.

• 음성과학
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• 제12권4호
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• pp.17-29
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• 2005

Time-frequency representation reveals some useful information about instantaneous frequency, instantaneous bandwidth and boundary of each AM-FM component of a speech signal. In many cases, the instantaneous frequency of each component is not constant. The variability of instantaneous frequency causes degradation of resolution in time-frequency representation. This paper presents a method of adaptively adjusting the transform kernel for preventing degradation of resolution due to time-varying instantaneous frequency. The transform kernel is the form of frequency modulated function. The modulation function in the transform kernel is determined by the estimate of instantaneous frequency which is approximated by first order polynomial at each time instance. Also, the window function is modulated by the estimated instantaneous. frequency for mitigation of fringing. effect. In the proposed method, not only the transform kernel but also the shape and the length of. the window function are adaptively adjusted by the instantaneous frequency of a speech signal.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.276-276
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• 2018

In this paper the potential of the Principle Component Analysis(PCA) technique that can be used to detect leaks in water pipe network blocks was evaluated. For this purpose the PCA was conducted to evaluate the relevance of the calculated outliers of a PCA model utilizing the recorded pipe flows and the recorded pipe leak incidents of a case study water distribution system. The PCA technique was enhanced by applying the computational algorithms developed in this study. The algorithms were designed to extract a partial set of flow data from the original 24 hour flow data so that the variability of the flows in the determined partial data set are minimal. The relevance of the calculated outliers of a PCA model and the recorded pipe leak incidents was analyzed. The results showed that the effectiveness of detecting leaks may improve by applying the developed algorithm. However, the analysis suggested that further development on the algorithm is needed to enhance the applicability of the PCA in detecting leaks in real-world water pipe networks.

• 한국콘텐츠학회논문지
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• 제12권8호
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• pp.96-104
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• 2012

기존 객체지향 개발 방식과 컴포넌트 개발 방식에서의 재사용성 문제는 모바일 개발에서도 해결해야하는 문제이다. 모바일 어플리케이션에서 기능을 변경하는 것은 모바일 어플리케이션 전체를 업그레이드 할 필요가 있는데, 이는 모바일 어플리케이션이 디바이스 내의 다른 어플리케이션들과 연계된 서비스와의 문제를 발생시킨다. 따라서 모바일 어플리케이션 내에 변경 가능성이 있는 기능들에 대해 재사용성을 고려하여 개발되어야 한다. 본 논문에서는 모바일 어플리케이션이 다양한 요구사항에 대해 재사용성을 높일 수 있는 커스터마이제이션 기법을 제안한다. 가변성 중에 데이터 기반의 가변성을 적용하여 변경을 요구하는 기능에 대해 자동으로 변경될 수 있는 자가적응 커스터마이제이션 기법을 제시한다.

• 한국환경과학회지
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• 제19권9호
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• pp.1083-1092
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• 2010

The spatial variability in the food chain structure of an estuary environment (Nanakita estuary, Japan) was investigated using fatty acid. Potential organic matter sources (terrestiral plants, macroalgae, benthic microalgae, dinflagellates and bacteria), sedimentary organic matters and benthic invertebrates (Nuttallia olivacea and Nereidae) were sampled in four locations with different tidal flat type. The main objective of the present study was to determine the origin of sediment and the food sources of N. olivacea and Nereidae along with small-scale spatial variability. The origin of sedimentary organic matters were mainly the fatty acid of bacteria and benthic microalgae. Especially, The organic matter of terrestrial plant origin was found the highest in station C. The diets of N. olivacea and Nereidae were found to be dominated by diatoms and terrestrial plants. Whereas, macroalgae and dinoflagellates showed little influence to benthic invertebrates. Moreover, according to principal component analysis, it is showed that benthic invertebrates in the same region are using the same food without relation with species. On the other hand, the N. olivacea and Nereidae of station D clearly contrasts with station B in terms of main food sources. From these results, it is suggested that food competition of benthic invertebrates revealed high a connection between small-scale spatial variability and food source in estuary.

• 전기학회논문지
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• 제66권7호
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• pp.1072-1077
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• 2017

Mean-reverting analysis refers to a way of estimating the underlining tendency after new data has evoked the variation in the equilibrium state. In this paper, we propose a new method to interpret the specular portraits of Premature Ventricular Contraction(PVC) arrhythmia by applying K-means unsupervised learning algorithm on electrocardiogram(ECG) data. Aiming at this purpose, we applied a mean-reverting model to analyse Heart Rate Variability(HRV) in terms of the modified poincare plot by considering PVC rhythm as the component of disrupting the homeostasis state. Based on our experimental tests on MIT-BIH ECG database, we can find the fact that the specular patterns portraited by K-means clustering on mean-reverting HRV data can be more clearly visible and the Euclidean metric can be used to identify the discrepancy between the normal sinus rhythm and PVC beats by the relative distance among cluster-centroids.

• 셀메드
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• 제5권1호
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• pp.4.1-4.4
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• 2015

Yoga is an ancient Indian system of life, encompassing various practices including practices for self-discipline and also for regulating the health states of the individual, being practiced for thousands of years. The present study aims at understanding the effect of two high frequency breathing practices over autonomic nervous system. Forty healthy male volunteers of age $21{\pm}2$ years with $9{\pm}3$ months of Yoga practice experience were recruited. The two high frequency Yoga breathing practices, kapalabhati (KB) and bhastrika (BH) were given as interventions randomly on either of the two days to minimise laboratory bias. They were assessed before and immediately after the interventions for heart rate, respiratory rate, heart rate variability (HRV), blood pressure and peripheral oxygen saturation. There was a significant increase in heart rate (p<0.01; p<0.001), systolic blood pressure (p<0.01; p<0.001), NN50 (p<0.01; p<0.001) component of HRV for both KB and BH groups respectively. There was a significant reduction in respiratory rate in both the groups (p<0.001, and p<0.05, BH and KB respectively) immediately following intervention. A significant increase in LF component of HRV and reduction in Diastolic blood pressure and high frequency (HF)component following KB was also observed (p<0.05, for all comparisons). The Mean peripheral oxygen saturation remained unaltered in both the groups (p>0.05).The results suggest that high frequency yoga breathing practices induce physiological arousal immediately as evidenced by increased blood pressure and heart rate. The sympathetic arousal was more following KB session as evidenced by an increased diastolic blood pressure, LF power and a decrease in HF power of HRV as compared to the BH session.

• 말소리와 음성과학
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• 제12권4호
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• pp.73-80
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• 2020

본 연구에서는 연속음성에서의 장시간 jitter 성분 측정 방법에 대해 고찰하였다. 기존의 jitter측정방법으로는 지속 발성한 모음을 대상으로 변동성을 측정하는 방법을 주로 사용하여왔다. 문장음성 등 연속음성의 경우는 문장에 따른 운율정보의 영향으로 기존의 측정법으로는 왜곡이 발생하게 된다. 이에 연속 발성에 대해 운율정보의 피치 변동을 상쇄시키는 방법을 제안하고자 한다. 피치 변동을 제거하는 방법으로는 분석구간내에서의 피치 변동을 다항식 보간법에 의해 변동 경향을 대표하는 곡선을 구하고 그 곡선을 기준으로 변이를 제거하였다. 이후 변이가 제거된 피치의 궤적으로부터 jitter를 측정하는 방법을 적용하여 피치 주파수의 변동성을 측정하고 기존의 지속모음에 의한 측정 방법과 비교하였다. 제안한 방법의 효용성 측정을 위해 Kay Pentax MEEI DB의 음성 표본을 사용하였다. 통계분석 결과 제안된 방법에 의해 연속음성으로부터 측정한 jitter 값은 동일 화자의 지속모음으로부터 측정한 파라미터 값과 유사한 변동성을 보여 주었다.

• 천문학회보
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• 제42권2호
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• pp.38.1-38.1
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• 2017

Symbiotic stars are long-orbital-period interacting binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this contribution, I will present some high-cadence, long-term optical light curves of confirmed and candidate symbiotic stars in the Magellanic Clouds. By careful visual inspection and combined time series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects, trying in particular to distinguish the evolutionary status of the cool component, to provide its first-order pulsation ephemeris and to link all this information with the physical parameters of the binary system as a whole. Finally, I will discuss a new, promising photometric technique, potentially able to discover Symbiotic Stars in the Local Group of Galaxies without the recourse to costly spectroscopic follow-up.

• Steel and Composite Structures
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• 제37권2호
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• pp.151-173
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• 2020

This paper aims to probabilistically evaluate performance of two types of I beam to box column (IBBC) connection. With the objective of considering the variability of seismic loading demand, statistical features of the inter-story drift ratio corresponding to the second, fifth and eleventh story of a 12-story steel special moment resisting frames are extracted through incremental dynamic analysis at global collapse state. Variability of geometrical variables and material strength are also taken into account. All of these random variables are exported as inputs to a probabilistic finite element model which simulates the connection. At the end, cumulative distribution functions of local seismic demand for each component of each connection are provided using histogram sampling. Through a parametric study on probabilistic local seismic demand, the influence of some geometrical random variables on the performance of IBBC connections is demonstrated. Furthermore, the probabilistic study revealed that IBBC connection with widened flange has a better performance than the un-widened flange. Also, a design procedure is proposed for WF connections to achieve a same connection performance in different stories.