• 천문학회보
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• 제41권2호
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• pp.64.2-64.2
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• 2016

Optical variability is one way to probe the nature of the central engine of AGN at smaller linear scales and previous studies have shown that optical variability is more prevalent at longer timescales and at shorter wavelengths. Especially, intra-night variability can be explained through the damped random walk model but small samples and inhomogeneous data have made constraining this model hard. To understand the properties and physical mechanism of optical variability, we are performing the KMTNet Active Nuclei Variability Survey (KANVaS). Test data of KMTNet in the COSMOS field was obtained over 2 separate nights during 2015, in B, V, R, and I bands. Each night was composed of 5 and 9 epochs with ~30 min cadence. To find AGN in the COSMOS field, we applied multi-wavelength selection methods. Different selection methods means we are looking different region in unification model of AGN, and 100~120, 400~500, 50~100 number of AGN are detected in X-ray, mid-infrared, and radio selection of AGN, respectively. We performed image convolution to reflect seeing fluctuation, then differential photometry between the selected AGN and nearby stars to achieve photometric uncertainty ~0.01mag. We employed one of the standard time-series analysis tools to identify variable AGN, chi-square test. Preliminarily results indicate that intra-night variability is found for X-ray selected, Type1 AGN are 23.6%, 26.4%, 21.3% and 20.7% in the B, V, R, and I band, respectively. The majority of the identified variable AGN are classified as Type 1 AGN, with only a handful of Type 2 AGN showing evidence for variability. The work done so far confirms that there are type and wavelength dependence of intra-night optical variability of AGN.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.93-96
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• 2015

본 논문에서는 상황 인식 센서를 활용한 산불 감지 시스템을 제안한다. 기존 기상 및 비전 센서 기반의 산불 방재 시스템의 경우 카메라 센서로 획득한 영상을 조명변화에 강인한 색상공간인 HSI(Hue, Saturation, Intensity) 모형으로 변환시켜 처리하여 산불영역에 대한 특징을 추출하고 있다. 그러나 이 경우 단일 카메라 센서가 넓은 범위에 화재를 감지하기 때문에 넓은 범위의 화재가 발생하기 전까지는 화재발생을 감지하는데 어려움이 있다. 또한 복합적인 상황에서의 화재 감지가 힘들뿐만 아니라 별도의 지속적인 경계가 필요한 지역에 대한 설정이 어렵다. 따라서 본 논문에서는 센서를 활용하여 실시간으로 온도, 습도, Co2, 불꽃유무정보를 습득하고 이 데이터들을 복합적인 상황에 따라 비교, 분석하고 그에 따른 가중치를 부여하여 화재를 판단하는 알고리즘을 제안한다. 또한 화재 상태를 나누어 집중적인 화재 감지가 필요한 구역에 차별적인 관리가 가능하게 한다.

• 한국주거학회논문집
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• 제11권2호
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• pp.1-12
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• 2000

Down-town community is an essential element for ESSD. But the population of down-town has been decreased since 1990's. Therefore this study is about how to improve the down-town residential tendency through the civic research, examination of related policies and legal system. And the result is as follows. First, Taegu has lots of problems as a residential space, that are caused by bad residential environment. They also, however, represent the validity of arrangement of down-town community and we could find the possibility for development. Second, Japan perceived the importance of down-town community and a great deal of effort was done to save residential space with various programs. But it is ignored in Korea for economic reason. Therefore we need to change our view of Down-town residence. Third, the role of government, people and specialist are important for the improvement of Down-town community. 1) The central government and ask its responsibility. 2) The local government makes the best use of present laws and is required of management with elasticity in favor of the regional character. And it need to set the future image and aim of the city. The aim should be the one that meets the practical need of down-town community and suitable programs need to be activated. 3) Generally, the citizens who are living in a region know it's problems the best. So the citizens themselves can advertise their Down-town community and participate to solve its problems 4) Down-town community requires a differential policy from general residence. Thus the professional have duty for the development of proper know-hows for Down-town community.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1093-1096
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• 2003

본 논문에서는, CMOS APS Image Sensor 내에 포함되어 회로의 면적을 줄인 새롭게 제안된 CMOS Bandgap Reference Bias Generator (BGR)를 온도 및 방사능에 대한 응답을 실험하였다. 제안된 BGR 회로의 설계 목표는 V/sub DD/는 2.5V이상이고, V/sub ref/는 0.75V ± 0.5mV 마진을 가지게 하는 것이다. 제안된 BGR회로는 Level Shifter를 갖는 Differential OP-amp단과 Feedback-Loop를 가지는 Cascode Current Mirror를 사용하여 저전압에서도 동작을 가능하게 하였으며, 높은 출력저항 특성을 가지도록 하였다. 제안된 BGR회로는 하이닉스 0.18㎛ ( triple well two-poly five-metal ) CMOS 공정을 이용하여 Test Chip을 제작하였다. 온도의 변화와 Co-60 노출조건 하에서 Total ionization dose (TID) effect된 BGR회로의 V/sub ref/를 측정하여, 이를 평가하였다. 온도에 대한 반응은, 25℃ 일 때의 V/sub ref/에 대해, 각각 45 ℃에서 0.128%. 70℃에서 0.768% 변화하였다. 그리고 온도가 25℃일 때 50krad와 100krad의 방사능을 조사 하였을 경우, V/sub ref/는 각각 2.466%, 그리고 4.612% 변화하였다.

• Imaging Science in Dentistry
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• 제32권2호
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• pp.89-97
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• 2002

Purpose: The objective of this study is to find the differentiating characteristics of ameloblastomas and odontogenic keratocysts of the jaw by analyzing computed tomography (CT) images of the lesions, clarify radiological characteristics associated with jaw lesions, and to make a diagnsis based on these findings. Materials and Methods : Test subjects were chosen among the patients who were diagnosed as having an odontogenic keratocyst or ameloblastoma at the Yonsei University Dental Hospital from January 1996 to December 2000 and had CT scans taken preoperatively. The subject pool was comprised of 51 cases of odontogenic keratocyst and 37 cases of ameloblastoma. The following measures were used for image analysis of the lesion: the anatomic location, CT pattern, mesiodistal width, buccolingual width, the ratios between mesiodistal width and buccolingual width, height, CT number, homogeneity of radiodensity, the appearance of a sclerotic rim, continuity of adjacent cortical bone, and displacement and resorption of adjacent teeth. Results: Comparing the CT patten, mesiodistal width, buccolingual width, height, CT number, homogeneity, appearance of sclerotic rim, continuity of adjacent cortical bone, there were statistically significant differences between ameloblastoma and odontogenic keratocyst test subjects (p<0.05). Comparing the ratios between mesiodistal width and buccolingual width, displacement and resorption of adjacent teeth, there were no statistically significant differences (p>0.05). Conclusion: We compared odontogenic keratocysts and ameloblastomas in CT scans. They occurred most frequently in the posterior to the ramus of the mandible. The findings of patterns of the CT images showed that size and border of lesions were more aggressive in ameloblastomas than in odontogenic keratocysts. The internal contents represented an increased attenuation area (IAA) in odontopenic keratocyst. Odontogenic keratocysts were shown to have higher CT numbers than ameloblastomas.

• Tuberculosis and Respiratory Diseases
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• 제73권3호
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• pp.182-186
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• 2012

Cryptococcosis is an invasive fungal infection, which is more common in immunocompromised patients. However, pulmonary cryptococcosis can occur in immunocompetent patients and should be considered on a differential diagnosis for nodular or mass-like lesions in chest radiograph. Recently, we experienced a patient with pulmonary cryptococcosis, successfully treated with oral fluconazole therapy. A 74-year-old female patient was referred for an evaluation of abnormal images, a large consolidative mass with multiple nodular consolidations and small nodules that mimics primary lung cancer with multiple lung to lung metastases. Computed tomography-guided lung biopsy confirmed the diagnosis of pulmonary cryptococcosis. The follow-up image taken after 4 months with oral fluconazole treatment showed marked improvement.

• BMB Reports
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• 제40권6호
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• pp.853-860
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• 2007

Resistance to anticancer drugs is a major obstacle in the effective treatment of tumors. To understand the mechanisms responsible for multidrug resistance (MDR), a proteomic approach was used to identify proteins that were expressed in different levels by the adriamycinresistant human gastric cancer cell line, SGC7901/ADR, and its parental cell line, SGC7901. Two-dimensional gel electrophoresis (2-DE) and image analysis was used to determine which protein spots were expressed in different levels by the two cell lines. These spots were then partially identified using ESI-Q-TOF mass spectrometry, and the differential expressional levels of the partially identified proteins were then determined by western blot analysis and real-time RT-PCR. Additionally, the association of Nucleophosmin (NPM1), a protein that was highly expressed by SGC7901/ADR, with MDR was analyzed using siRNA. As a result of this study, well-resolved, reproducible 2-DE patterns of SGC7901/ADR and SGC7901 were established, and 16 proteins that may playa role in the development of thermo resistance were identified. Additionally, suppression of NPMl expression was found to enhance adriamycin chemosensitivity in SGC7901/ADR. These results provide a fundamental basis for the elucidation of the molecular mechanism of MDR, which may assist in the treatment of gastric cancer.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.788-795
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• 2015

Two dimensional-fluorescence difference gel electrophoresis (2D DIGE) is an emerging technique for comparative proteomics, which improves the reproducibility and reliability of differential protein expression analysis between samples. The purpose of this study was to investigate bovine pregnancy-specific proteins in the proteome between bovine pregnant and non-pregnant serum using DIGE technique. Serums of 2 pregnant Holstein dairy cattle at day 21 after artificial insemination and those of 2 non-pregnant were used in this study. The pre-electrophoretic labeling of pregnant and non-pregnant serum proteins were mixed with Cy3 and Cy5 fluorescent dyes, respectively, and an internal standard was labeled with Cy2. Labeled proteins with Cy2, Cy3, and Cy5 were separated together in a single gel, and then were detected by fluorescence image analyzer. The 2D DIGE method using fluorescence CyDye DIGE flour had higher sensitivity than conventional 2D gel electrophoresis, and showed reproducible results. Approximately 1,500 protein spots were detected by 2D DIGE. Several proteins showed a more than 1.5-fold up and down regulation between non-pregnant and pregnant serum proteins. The differentially expressed proteins were identified by MALDI-TOF mass spectrometer. A total 16 protein spots were detected to regulate differentially in the pregnant serum, among which 7 spots were up-regulated proteins such as conglutinin precursor, modified bovine fibrinogen and IgG1, and 6 spots were down-regulated proteins such as hemoglobin, complement component 3, bovine fibrinogen and IgG2a three spots were not identified. The identified proteins demonstrate that early pregnant bovine serum may have several pregnancy-specific proteins, and these could be a valuable information for the development of pregnancy-diagnostic markers in early pregnancy bovine serum.

• 방송공학회논문지
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• 제17권4호
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• pp.670-675
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• 2012

정지영상 및 동영상내의 화면에서 관심영역이 설정되고, 비관심영역에 비하여 관심영역에 높은 화질이 제공되면 전체적으로 주관적 화질이 증대하게 된다. 관심영역은 색상 카메라만을 이용하여 추출하게 되면 계산이 복잡해질 뿐만아니라 추출의 정확도도 떨어지게 된다. 따라서 본 논문에서는 관심영역을 설정하기 위하여 깊이 카메라를 이용하며, 카메라와 관심영역 객체별 거리를 산출하고, 거리에 따라 객체의 화질을 차별적으로 제어하는 방법을 제안한다. 즉, 거리가 먼 객체에는 높은 양자화 계단크기를 적용하지만, 상대적으로 거리가 가까운 객체에는 낮은 양자화 계단크기를 적용하여 화질을 좋게 한다. 본 논문에서 제안된 방법에 의해 객체의 거리별로 양자화계단의 크기를 차등적으로 적용함으로써 주관적 화질의 개선이 이루어졌으며 모의실험을 바탕으로 확인할 수 있다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권6호
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• pp.654-662
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• 2010

본 논문은 2단계 연속(cascade) 방법을 이용한 향상된 보행자/비보행자 인식 알고리즘을 제안한다. 인식을 위한 분류기로는 약한 분류기를 강한 분류기로 만드는 아다부스트 알고리즘을 적용하였다. 먼저 두 가지 특징벡터를 추출 한다: (i) 기존의 기울기 히스토그램(HOG) 특성과 (ii) 한 점이 가지는 곡률특성 네 가지를 이용한 곡률-HOG를 제안하고 이용하였다. 그 다음 훈련 영상을 통하여 두 가지의 특징 벡터에 대해 약한 분류기로부터 강한 분류기를 얻었으며, 인식은 입력 영상으로부터 하나의 특징을 선택하여 이미 만들어진 강한 분류기를 통하여 1차적인 인식과 오인식을 실시하며, 오인식된 영상에 대해 2차적인 특징을 투입하여 이에 해당하는 강한 분류기를 통하여 2단계 아다부스트 알고리즘을 적용하여 최종적인 인식결과를 얻는다. 두 가지의 서로 다른 특성 벡터를 이용하여 연속 방법에 의한 2단계 아다부스트 알고리즘을 적용한 결과 기존의 실험 방법보다 더 정확한 인식 결과를 얻을 수 있었다.