• 대한원격탐사학회지
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• 제37권5_1호
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• pp.885-901
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• 2021

천리안위성 2A호의 2분 주기 고속 관측(rapid-scan) 자료를 이용하여, 가시·수증기·적외 채널의 시간 해상도와 표적의 크기가 해당 채널의 중규모 대기운동벡터 생산에 미치는 영향을 분석하였다. 중규모 대기운동벡터 산출을 위하여 2-10분의 영상 시간 간격 변화 하에서 표적의 크기를 8×8에서 40×40 화소 크기로 변환시키며, 시·공간적인 조건 변화에 따른 벡터 생산량과 평균 속력, 오차 특성의 변화 양상을 비교하였다. 그 결과, 표적의 크기가 작을수록 위성의 시간 간격 변화에 따른 벡터 개수의 변화와, 표준화된 평균 제곱근 편차(Normalized Root Mean Squared Vector Difference; NRMSVD) 값의 변화가 더욱 뚜렷해졌다. 또한 고도별 오차 특성 분석 결과에서는 평균 속력이 낮고 대기 현상의 시·공간 규모가 작은 하층(700-1000 hPa)의 경우, 짧은 시간 간격의 영상 자료와 작은 표적을 이용하는 것이 벡터 산출에 더욱 유리하게 작용하는 것을 확인할 수 있었다. 위성의 시간 간격과 표적의 크기는 대기 순환의 시·공간 규모와 밀접한 연관이 있는 요소이다. 따라서, 대기운동벡터 활용 목적에 맞게 표적 크기와 위성 시간 간격을 최적화하는 과정이 필요하며, 중규모 기상현상의 실황 분석을 위한 대기운동벡터 산출 알고리즘에서는 표적 크기와 영상 시간 간격을 각각 16×16, 4분으로 설정해주는 것이 가장 적합하다고 판단된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.176-179
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• 2004

The effects of a temporal image sticking phenomenon on the subsequent dark and white background images are investigated in 42-inch PDP-TV and the reducing method is proposed In addition, the changes in luminance and temperature with an increase in time with the conventional and large sustain gap. The temporal dark image sticking was reduced considerably by decreasing background luminance and it was found that the temporal image sticking with large sustain gap was reduced when compared with the conventional sustain gap.

• Water Engineering Research
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• 제3권1호
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• pp.31-44
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• 2002

The effect of diurnal cycle, intermittent visit of observation satellite, sensor installation, partial coverage of remote sensing, heterogeneity of soil properties and precipitation to the soil moisture estimation error were analyzed to present the global sampling strategy of soil moisture. Three models, the theoretical soil moisture model, WGR model proposed Waymire of at. (1984) to generate rainfall, and Turning Band Method to generate two dimensional soil porosity, active soil depth and loss coefficient field were used to construct sufficient two-dimensional soil moisture data based on different scenarios. The sampling error is dominated by sampling interval and design scheme. The effect of heterogeneity of soil properties and rainfall to sampling error is smaller than that of temporal gap and spatial gap. Selecting a small sampling interval can dramatically reduce the sampling error generated by other factors such as heterogeneity of rainfall, soil properties, topography, and climatic conditions. If the annual mean of coverage portion is about 90%, the effect of partial coverage to sampling error can be disregarded. The water retention capacity of fields is very important in the sampling error. The smaller the water retention capacity of the field (small soil porosity and thin active soil depth), the greater the sampling error. These results indicate that the sampling error is very sensitive to water retention capacity. Block random installation gets more accurate data than random installation of soil moisture gages. The Walnut Gulch soil moisture data show that the diurnal variation of soil moisture causes sampling error between 1 and 4 % in daily estimation.

• Journal of Audiology & Otology
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• 제24권3호
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• pp.133-139
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• 2020

Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

• 대한청각학회지
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• 제24권3호
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• pp.133-139
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• 2020

Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

• 정보처리학회논문지D
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• 제15D권4호
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• pp.485-494
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• 2008

인터넷이 광범위하게 활용됨에 따라 검색 키워드, 멀티미디어 객체, 웹 페이지, 블로그 등의 다양한 웹 객체들이 크게 증가하고 있다. 이러한 웹 객체들의 인기도는 시간에 따라 변화하며, 그러한 웹 객체 인기도의 시간적 패턴에 대한 마이닝이 여러 가지 웹 응용에 필요한 중요한 연구 과제가 되고 있다. 예를 들어, 검색 키워드에 대한 인기도 패턴의 분석은 앞으로 인기가 높아질 키워드를 미리 예측할 수 있게 하여 광고주들에게 키워드를 판매하기 위한 가격을 결정하는 데에 중요한 자료가 될 수 있다. 하지만, 웹 객체 인기도가 시간에 따라 변화하고 웹 객체의 개수가 매우 방대하다는 특성으로 인하여 웹 객체 인기도에 대한 분석은 매우 어려운 문제이다. 본 논문에서는 웹 객체 인기도의 시간적 패턴을 마이닝하기 위한 효율적인 알고리즘을 제안한다. 본 논문은 웹 객체 인기도를 시계열로 표현하고, 두 웹 객체 인기도 간의 유사성을 측정하기 위하여 gap 척도를 제안한다. gap 척도의 효율적인 계산을 위하여 FFT를 활용한 알고리즘을 제안하고, 밀도기반 클러스터링 알고리즘을 이용하여 유사한 인기도 추세를 갖는 웹 객체들의 클러스터를 생성한다. 본 논문에서는 웹 객체 인기도가 특정 분포를 따르거나 주기적이라고 가정하지 않는다. Google Trends 웹 사이트로부터 구한 검색 키워드 인기도를 이용한 실험을 통하여, 제안된 알고리즘이 실세계 응용에서 유용함을 보인다.

• 한국음향학회지
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• 제41권1호
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• pp.58-63
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• 2022

본 연구는 저주파수 순음(264 Hz, 373 Hz, 528 Hz)을 이용하여 Within-/Cross-Channel Gap Detection Thresholds(WC/CC GDTs)를 통해서 피치인식 및 시간적 청각정보처리능력 특성을 알아보기 위해 실험연구를 실시하였다. 정상청력을 갖는 청년층 40명과 장년층 20명을 대상으로 WC/CC GDTs를 측정·비교분석하였다. WC GDTs 결과는 두 그룹 모두 평균적으로 2 ms ~ 4 ms를 갖으며, 통계적으로 유의미한 차이를 보이지 않았다. CC GDTs는 WC GDTs에 비해 두 그룹 모두 크게 증가하였으며, 특히 장년층의 결과가 청년층 결과에 비해 모두 8배 ~ 10배 증가하여 통계적으로 유의미한 차이를 보였다. CC GDTs는 선/후행음의 주파수의 차이가 커질수록 모두 증가하는 경향이 나타났으며, 청년층은 증가폭이 일정한 반면 장년층은 증가폭이 둔화되는 경향을 보였다. 또한, 이러한 자료는 기존 음악적 자극에 대한 GDT와는 다른 경향을 나타내었다. 연구 결과는 GDT가 피치인식 메커니즘에 영향을 미칠 수 있으며 청각 신경계의 비선형 반응에 대한 심리음향적 근거자료로 활용될 수 있을 것이다.

• Water Engineering Research
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• 제1권3호
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• pp.209-222
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• 2000

A spectral formalism was applied to quantify the sampling errors due to spatial and/or temporal gaps in soil moisture measurements. The lack of temporal measurements of the two-dimensional soil moisture field makes it difficult to compute the spectra directly from observed records. Therefore, the space-time soil moisture spectra derived by stochastic models of rainfall and soil moisture was used in their record. Parameters for both models were tuned with Southern Great Plains Hydrology Experiment(SGP'97) data and the Oklahoma Mesonet data. The structure of soil moisture data is discrete in space and time. A design filter was developed to compute the sampling errors for discrete measurements in space and time. This filter has the advantage in its general form applicable for all kinds of sampling designs. Sampling errors of the soil moisture estimation during the SGP'97 Hydrology Experiment period were estimated. The sampling errors for various sampling designs such as satedlite over pass and point measurement ground probe were estimated under the climate condition between June and August 1997 and soil properties of the SGP'97 experimental area. The ground truth design was evaluated to 25km and 50km spatial gap and the temporal gap from zero to 5 days.

• Journal of Audiology & Otology
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• 제23권2호
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• pp.96-102
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• 2019

Background and Objectives: Temporal bone fracture (TBF) is a common occurrence in cases of head trauma. Although the incidence of temporal bone concussion (TBC) has increased in cases of head trauma, it has not been extensively studied. We assessed the characteristics of TBF and TBC in patients with head trauma. Subjects and Methods: We conducted a retrospective review of 432 patients with head injury who visited our hospital between January 2011 and April 2016. Of these patients, 211 who met the inclusion criteria were included in the study. Their clinical characteristics, causes of injury, and hearing function were analyzed. Results: Among the 211 patients, 157 had TBFs and 54 had TBCs. Ear symptoms were more common among patients with TBF than among those with TBC. Car accidents were the most common cause of both TBF and TBC, but assault and sports injuries were more common among patients with TBC than among those with TBF. The occurrence of facial palsy in both cases of TBF and TBC. Hearing loss was observed among 35 patients with TBF and 11 patients with TBC. However, patients with TBF showed conductive hearing loss with an air-bone gap. Hearing function of these patients with TBF recovered with a reduced air-bone gap, but the patients with TBC showed little recovery. Conclusions: Emergency physicians should focus more on temporal bone injury in patients with head trauma. Therefore, an early complete diagnostic battery, which includes high-resolution computed tomography, audiometric tests, neurologic examination, and vestibular tests, be performed in patients with head trauma.

• 대한청각학회지
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• 제23권2호
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• pp.96-102
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• 2019

Background and Objectives: Temporal bone fracture (TBF) is a common occurrence in cases of head trauma. Although the incidence of temporal bone concussion (TBC) has increased in cases of head trauma, it has not been extensively studied. We assessed the characteristics of TBF and TBC in patients with head trauma. Subjects and Methods: We conducted a retrospective review of 432 patients with head injury who visited our hospital between January 2011 and April 2016. Of these patients, 211 who met the inclusion criteria were included in the study. Their clinical characteristics, causes of injury, and hearing function were analyzed. Results: Among the 211 patients, 157 had TBFs and 54 had TBCs. Ear symptoms were more common among patients with TBF than among those with TBC. Car accidents were the most common cause of both TBF and TBC, but assault and sports injuries were more common among patients with TBC than among those with TBF. The occurrence of facial palsy in both cases of TBF and TBC. Hearing loss was observed among 35 patients with TBF and 11 patients with TBC. However, patients with TBF showed conductive hearing loss with an air-bone gap. Hearing function of these patients with TBF recovered with a reduced air-bone gap, but the patients with TBC showed little recovery. Conclusions: Emergency physicians should focus more on temporal bone injury in patients with head trauma. Therefore, an early complete diagnostic battery, which includes high-resolution computed tomography, audiometric tests, neurologic examination, and vestibular tests, be performed in patients with head trauma.