• 천문학회보
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• 제43권2호
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• pp.45.3-46
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• 2018

Oscillations in a sunspot are easily detected through the Doppler velocity observation. Although the sunspot oscillations look erratic, the wavelet analysis show that they consist of successive wave packets which have strong power near three or five minutes. Previous studies found that 3-min oscillation at the chromosphere is a visual pattern of upward propagating acoustic waves along the magnetic field lines. Resent multi-height observations help this like vertical study, however, we also focus on horizontal facet to extend three dimensional understand of sunspot waves. So, we investigate a fragmented sunspot expected to have complex wave profiles according to the positions in the sunspot observed by the Fast Imaging Solar Spectrograph. We choose 4 points at different umbral cores as sampling positions to determine coherence of oscillations. The sets of cross-correlation with three and five minutes bandpass filters during a single wave packet reveal interesting results. Na I line show weak correlations with some lags, but Fe I and Ni I have strong correlations with no phase difference over the sunspots. It is more remarkable at Ni I line with 3-min bandpass that all sets of cross-correlation look like the autocorrelation. We can interpret this as sunspot oscillations occur spontaneously over a sunspot at photosphere but not at chromosphere. It implies a larger or deeper origin of 3-min sunspot oscillation.

• 대한간호학회지
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• 제25권1호
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• pp.99-109
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• 1995

Post-operative wound infections have been the serious problems in nursing care in the operating room and appear to be strongly related to the infection occurring during the operation. The purpose of this study is to identify the level of contamination in saline used in the operation and also examine the correlation between the contaminated saline and the length of the operation, and unclean atmospheric factor. Subjects for this study include 13 cases of operation performed at the operative theatre of a hospital in Seoul area. Test samples and related data were collected from this medical facility between Oct. 6 through Dec. 10, 1994 by the author and anurse who worked in the operating room. For the study, multiple batches of saline sample were collected at the various time intervals duringthe operation and filtered through the membrane filters. Viable microorganisms retained on the filters were cultured on the appropriate culture media and the levels of existing cells in saline were enumerated according to Koch's method. In the analyses of the data, Pearson's correlation coefficient was obtained for the examination of relationship between the length of operation and numbers of microorganisms existing in saline and for the comparison of the differences in numbers if microrganisms in saline sample collected at the various operative stages, e. g. pre-incision, excision and skin suturing stages, ANOVA and Scheff Tests were performed. The results of this study are summarized as follows. 1) The lenth of the operation and numbers of microorganisms in the saline used in the operation appeared to be significantly correlated (r=0.5467, P<0,001). 2) In case of saline exposed to air, but not used in the operation, the length of exposure to the air and the numbers of microorganisms present in saline also showed an apparent correlation(r=0.5087, P<0. 001). 3) The frequencies of occurrence of microorganisms in saline used in the operation and in saline exposed only to the air in the given time showed significant differences(t=3.73, p=.0000). 4) In case of saline used in the operation, there is significant differences in its numbers of contained microorganisms between the operative stages ; pre-incision, excision, and skin suture (F=17.7500, p=.0000). 5) In case of saline exposed only to the air in the given time, there is significant differences in its numbers of contained microorganisms between the operative stages . pre-incision, excision, and skin suture(F=6.3807, p=.00031).

• 한국통신학회논문지
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• 제42권4호
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• pp.819-830
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• 2017

FM 신호 기반 PCL 시스템은 FM 송신탑에서 송신되는 신호를 이용하여 이동하는 표적의 위치를 추적하는 수동형 레이더 기술로서, 송신탑에서 수신기에 LOS (line-of-sight)로 입사되는 직접경로 신호와 표적으로부터 반사된 표적반사 신호의 상호 상관 함수를 유도하여 표적의 위치를 추적한다. 하지만, 직접경로 신호와 지형 및 지표면 등에서 반사되는 간섭 신호가 표적반사 신호 획득을 위한 감시 채널에 동시에 측정되며, 이에 따라 표적의 위치를 정확하게 탐지하지 못하는 문제가 발생한다. 간섭 신호 제거에는 적응 필터가 효과적인 것으로 알려져 있지만, 기존 연구에서는 상호 상관 함수나 적응 필터 입출력 신호의 전력 비율로부터 간섭 신호의 제거 성능을 유도하기 때문에, 정확한 성능 분석이 어려운 문제가 존재하였다. 본 논문에서는 필터 계수의 각 성분이 특정한 간섭 신호를 제거하기 위해 유도된다는 특징을 활용하여, 각 간섭 신호 제거 성능을 적응 필터 계수에 대한 함수로 정리한다. 제안한 성능 분석 방법을 기반으로 적응 필터 기법의 성능을 비교 및 분석하여, 제안한 방법이 간섭 신호 제거 성능 분석에 효과적으로 활용될 수 있음을 보인다.

• 정보과학회 논문지
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• 제41권12호
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• pp.1066-1074
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• 2014

본 논문에서는 시공간 정보를 포함하는 트윗 스트림에서 비정상적인 이벤트에 대한 상관관계를 사용자에게 시각적으로 분석하는 방법을 다양한 실험을 통하여 제안한다. 제안하는 방법으로는 트윗에서 토픽 모델링을 수행한 다음 계절요인과 추세요인을 반영한 시계열 분석 기법을 이용하여 비정상적인 이벤트 후보군을 추출한다. 추출된 토픽이 포함되어 있는 데이터를 대상으로 다시 한 번 토픽을 추출하여 시계열 분석을 수행한 다음 앞서 추출한 토픽과의 상관관계를 분석하여 비정상적인 이벤트를 탐지할 수 있도록 하였다. 비정상 이벤트를 탐지하는 모든 과정에 시각적 분석 방법을 이용하여 단순한 수치 정보가 아닌 시각적 패턴 형태로 나타냄으로써 사용자는 직관적으로 비정상 이벤트의 동향과 주기적인 패턴을 분석할 수 있도록 하였다. 실험은 2014년 1월 1일부터 2014년 6월 30일까지 국내에서 발생한 트윗을 대상으로 2개의 사건[경주 마우나 리조트 붕괴 사건(2014.02.17.), 진도 여객선 침몰 사건(2014.04.16.)]에 대해 시각적 분석 시스템을 적용하여 사용자는 쉽게 데이터를 분석하고 이해할 수 있음을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4438-4460
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• 2017

The Kernelized Correlation Filters (KCF) tracker has caused the extensive concern in recent years because of the high efficiency. Numerous improvements have been made successively. However, due to the abrupt motion between the consecutive image frames, these methods cannot track object well. To cope with the problem, we propose an extended KCF tracker based on swarm intelligence method. Unlike existing KCF-based trackers, we firstly introduce a swarm-based sampling method to KCF tracker and design a unified framework to track smooth or abrupt motion simultaneously. Secondly, we propose a global motion estimation method, where the exploration factor is constructed to search the whole state space so as to adapt abrupt motion. Finally, we give an adaptive threshold in light of confidence map, which ensures the accuracy of the motion estimation strategy. Extensive experimental results in both quantitative and qualitative measures demonstrate the effectiveness of our proposed method in tracking abrupt motion.

• 한국환경보건학회지
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• 제26권4호
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• pp.1-8
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• 2000

The objective of this study was to identify the sources and to estimate the source contributions to the atmospheric TSP(total suspended particulate matter) and PM-10(particulate matter with aerodynamic diameters less than 10$\mu\textrm{m}$) concentration in Taegu area. A total of 84 samples was collected during the January to December 1999. TSP and PM-10 were collected on filters by portable air sampler, and heavy metals in TSP and PM-배 were analyzed by ICO(Inductively Coupled Plasma Spectrometery) after preliminary treatment. The results were follow as : First, annual average of TSP and PM-10 concentration was 123 and 69$\mu\textrm{g}$/㎥ respectively. The concentration of TSP and PM-10 were highest in winter season compared to other seasons. Second, the concentration of Al, Fe, Mn were higher in TSP than in PM-10, indicating that these heavy metals are generally associate with natural contributions. Third, metal combinations showed that a high correlation among concentrations of heavy metals were follows: As Al, Fe and Mn in TSP ; Ni, Cr, Cd and Pb in PM-10. Finally, Statistical analysis was performed using Principal Components Analysis(PCA) in order to find possible sources of the pollutants. The factor analysis was permitted to identify four major sources(soil/road dust resuspension, waste incineration, furl combustion, vehicular emission) in each fraction. These source accounted for at least 83, 85% of variance of TSP and PM-10 concentration in Taegu area.

• Journal of Pharmaceutical Investigation
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• 제37권6호
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• pp.377-395
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• 2007

Near infrared(NIR) spectral data have been used for the noninvasive analysis of various biological samples. Nonetheless, absorption bands of NIR region are overlapped extensively. It is very difficult to select the proper wavelengths of spectral data, which give the best PCR(principal component regression) models for the analysis of constituents of biological samples. The NIR data were used after polynomial smoothing and differentiation of 1st order, using Savitzky-Golay filters. To find the best PCR models, all-possible combinations of available principal components from the given NIR spectral data were derived by in-house programs written in MATLAB codes. All of the extensively generated PCR models were compared in terms of SEC(standard error of calibration), $R^2$, SEP(standard error of prediction) and SECP(standard error of calibration and prediction) to find the best combination of principal components of the initial PCR models. The initial PCR models were found by SEC or Malinowski's indicator function and a priori selection of spectral points were examined in terms of correlation coefficients between NIR data at each wavelength and corresponding concentrations. For the test of the developed program, aqueous solutions of BSA(bovine serum albumin) and glucose were prepared and analyzed. As a result, the best PCR models were found using a priori selection of spectral points and the final model selection by SEP or SECP.

• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.494-499
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• 2013

In this paper, we present an optical encryption and information authentication of 3D objects considering wireless channel characteristics. Using the optical encryption such as double random phase encryption (DRPE) and 3D integral imaging, a 3D scene with encryption can be transmitted. However, the wireless channel causes the noise and fading effects of the 3D transmitted encryption data. When the 3D encrypted data is transmitted via wireless channel, the information may be lost or distorted because there are a lot of factors such as channel noise, propagation fading, and so on. Thus, using digital modulation and maximum likelihood (ML) detection, the noise and fading effects are mitigated, and the encrypted data is estimated well at the receiver. In addition, using computational volumetric reconstruction of integral imaging and advanced correlation filters, the noise effects may be remedied and 3D information may be authenticated. To prove our method, we carry out an optical experiment for sensing 3D information and simulation for optical encryption with DRPE and authentication with a nonlinear correlation filter. To the best of our knowledge, this is the first report on optical encryption and information authentication of 3D objects considering the wireless channel characteristics.

• 한국산업보건학회지
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• 제31권1호
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• pp.13-21
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• 2021

Objectives: The purpose of this study was to evaluate the exposures of cashiers who work at expressway tollbooths. Methods: We measured temperature(temp.), relative humidity(RH), and contaminants with direct reading instruments at ten expressway toll gate in September 2015. Elemental carbon was collected on the quartz filters and analyzed with an OCEC analyzer. Results: The average levels for temp., RH, carbon monoxide, carbon dioxide, dust(PM10), and black carbon were respectively 24.6~27.8℃, 32.3~65.3%, 0.5~1.2 ppm, 456~559 ppm, 12~111 ㎍/㎥, and 3.1~10.1 ㎍/㎥ at each tollbooth. The concentrations of elemental carbon within the tollbooth(1.8~7.2 ㎍/㎥) were lower than outdoors(2.5~10.0 ㎍/㎥), but exhibited a high correlation(r2=0.855). The exposure levels for carbon monoxide, black carbon, and elemental carbon in the tollbooths were significantly higher than the offices. The concentrations of black carbon and elemental carbon showed a high correlation(r2=0.756). Conclusions: The levels of contaminants were below the occupational exposure limits in the expressway tollbooth. There were ventilation and air conditioning systems in the booths, but it is necessary to maintain and use the systems properly.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.13-16
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• 2000

This paper presents a robust method to combine a collection of images with small fields of view to obtain an image with a large field of view. In the previous works, there are two main areas which one is a cross correlation-based method and the other is a feature-based method. The former is based on motion estimation from video sequences. so there are a problem on rotating a camera about optical axis. In the latter method, it is difficult to match correspondence feature points correctly.'re find correct correspondences, we proposed the geometrical feature model and correspondence filters and the Gaussian distribution weight function to blend the images smoothly. The experiments show that our method is robust and effective.