• 천문학회보
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• 제42권2호
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• pp.79.2-79.2
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• 2017

To dynamically and chemically understand how filaments, dense cores, and stars form under different environments, we are conducting a systematic mapping survey of nearby molecular clouds using the TRAO 14 m telescope with high ($N_2H^+$ 1-0, $HCO^+$ 1-0, SO 32-21, and $NH_2D$ v=1-0) and low ($^{13}CO$ 1-0, $C^{18}O$ 1-0) density tracers. The goals of this survey are to obtain the velocity distribution of low dense filaments and their dense cores for the study of their origin of the formation, to understand whether the dense cores form from any radial accretion or inward motions toward dense cores from their surrounding filaments, and to study the chemical differentiation of the filaments and the dense cores. Until the 2017A season, the real OTF observation time is ~760 hours. We have almost completed mapping observation with four molecular lines ($^{13}CO$ 1-0, $C^{18}O$ 1-0, $N_2H^+$ 1-0, and $HCO^+$ 1-0) on the six regions of molecular clouds (L1251 of Cepheus, Perseus West, Polaris South, BISTRO region of Serpens, California, and Orion B). The cube data for $^3CO$ and $C^{18}O$ lines were obtained for a total of 6 targets, 57 tiles, 676 maps, and $7.1deg^2$. And $N_2H^+$ and $HCO^+$ data were added for $2.2deg^2$ of dense regions. All OTF data were regridded to a cell size of 44 by 44 arcseconds. The $^{13}CO$ and $C^{18}O$ data show the RMS noise level of about (0.1-0.2) K and $N_2H^+$ and $HCO^+$ data show about (0.07-0.2) K at the velocity resolution of 0.06 km/s. Additional observations will be made on some regions that have not reached the noise level for analysis. To identify filaments, we are using and testing programs (DisPerSE, Dendrogram, FIVE) and visual inspection for 3D image of cube data. A basic analysis of the physical and chemical properties of each filament is underway.

• Applied Microscopy
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• 제35권4호
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• pp.91-97
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• 2005

이하선의 선세포와 분비과립을 작은땃쥐 Crocidura suaveolens와 우수리땃쥐 C. lasiura에서 연구하였다. 두 종 모두의 이하선은 장액선세포 한 종류만을 가지는 장액선이었고 선세포, 사이관, 과립관 그리고 줄무늬관들은 평범하였다. 작은땃쥐의 경우, 장액선세포는 잘 발달된 조면소포체, 현저한 골지체, 몇몇의 큰 미토콘드리아와 성숙 혹은 융합하고 있는 많은 중간 정도의 전자 밀도 과립들을 가지고 있었다. 미성숙 선세포의 분비과립들은 미세하고 강한 전자 밀도의 알갱이만으로 혹은 알갱이들이 주가 되었고 불분명한 경계막을 가지고 있었고, 성숙 분비과립들은 균일하고 옅은 중심부를 가지고 그 주변에 미세하고 강한 전자밀도의 알갱이들과 명확한 경계막을 가지고 있었다. 우수리땃쥐의 경우, 선세포는 잘 발달된 조면소포체, 현저한 골지체, 몇몇의 큰 미토콘드리아 뿐 아니라 성숙 혹은 융합하고 있는 많은 진한 전자 밀도의 분비과립들을 가지고 있었다. 미성숙 선세포 분비과립들은 옅고 거친 알갱이들만으로 채워져 있었으며 불명확한 경계막을 가지고 있었고, 성숙 분비과립들은 진하고 거친 알갱이들만으로 채워져 있었고 명확한 경계막을 가지고 있었다. 결국, 작은땃쥐의 이하선 분비과립은 광학과 전자현미경 수준에서 중간 정도의 전자밀도로, 우수리땃쥐의 분비과립은 광학 현미경 수준에서는 아주 진하게, 전자현미경에서는 진하게 관찰되었다.

• 대한방사선기술학회지:방사선기술과학
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• 제34권1호
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• pp.1-7
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• 2011

유방영상에서 유방암 진단의 정확도를 평가하고 유방암 환자들의 특성을 알아보고자 한, 본 논문은 screen-film 방식의 유방영상검사를 실시한 유방암 환자 85명을 대상으로 2010년 3월부터 2010년 10월까지 연구 조사되었다. 유방암 환자들의 평균 나이는 51.9세로 조사되었고, 유방암의 발생 부위는 상외측(UOQ)이 전체의 43.5%로 가장 많았다. 연령에 따른 유방암 발생은 40~49세에서 37.6%(32/85)로 모든 연령대에서 가장 높게 나타났다. 유방암 환자들의 breast composition(유방조직 밀도)은 fatty breast가 30.6%(26/85), dense breast가 69.4%(59/85)로 나타나, 70%에 가까운 유방암 환자들이 dense breast의 형태를 띠고 있었다. 또한 fatty breast를 가진 환자들의 평균 나이는 62.4세이었고, dense breast 환자들의 평균 나이는 46.5세로 유방실질의 양상에 따라 유의한 연령차가 있는 것으로 조사되었다(P = 0.000). 유방암 환자들의 유방영상 위음성률은 27.1%(23/85)로 조사되었고, 민감도는 72.9%(62/85)로 조사되었다. 또한, dense breast를 가진 유방암 환자들의 유방영상 위음성률은 32.2%(19/59)이고 민감도는 67.8%(40/59)로 나타났다.

• Korean Journal of Radiology
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• 제23권11호
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• pp.1031-1043
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• 2022

Objective: To compare digital breast tomosynthesis (DBT) and MRI as an adjunct to full-field digital mammography (FFDM) for the preoperative evaluation of women with breast cancer based on mammographic density. Materials and Methods: This retrospective study enrolled 280 patients with breast cancer who had undergone FFDM, DBT, and MRI for preoperative local tumor staging. Three radiologists independently sought the index cancer and additional ipsilateral and contralateral breast cancers using either FFDM alone, DBT plus FFDM, or MRI plus FFDM. Diagnostic performances across the three radiologists were compared among the reading modes in all patients and subgroups with dense (n = 186) and non-dense breasts (n = 94) according to mammographic density. Results: Of 280 patients, 46 (16.4%) had 48 additional (39 ipsilateral and nine contralateral) cancers in addition to the index cancer. For index cancers, both DBT plus FFDM and MRI plus FFDM showed sensitivities of 100% in the non-dense group. In the dense group, DBT plus FFDM showed lower sensitivity than that of MRI plus FFDM (94.6% vs. 99.6%, p < 0.001). For additional ipsilateral cancers, DBT plus FFDM showed specificity and positive predictive value (PPV) of 100% in the non-dense group, but sensitivity and negative predictive value (NPV) were not statistically different from those of MRI plus FFDM (p > 0.05). In the dense group, DBT plus FFDM showed higher specificity (98.2% vs. 94.1%, p = 0.005) and PPV (83.1% vs. 65.4%; p = 0.036) than those of MRI plus FFDM, but lower sensitivity (59.9% vs. 75.3%; p = 0.049). For contralateral cancers, DBT plus FFDM showed higher specificity than that of MRI plus FFDM (99.0% vs. 96.7%, p = 0.014), however, the other values did not differ (all p > 0.05) in the dense group. Conclusion: DBT plus FFDM showed an overall higher specificity than that of MRI plus FFDM regardless of breast density, perhaps without substantial loss in sensitivity and NPV in the diagnosis of additional cancers. Thus, DBT may have the potential to be used as a preoperative breast cancer staging tool.

• Clinical and Experimental Pediatrics
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• 제53권7호
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• pp.766-769
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• 2010

Dense deposit disease (DDD) is a rare disorder characterized by the deposition of abnormal electron-dense material within the glomerular basement membrane of the kidneys. The diagnosis is made in most patients between 5 and 15 years of age, and within 10 years, approximately half of the affected patients progress to end-stage renal disease. We report a rare case of regressive DDD without C3 deposition after steroid therapy in an 11-year-old boy. The patient presented with edema, gross hematuria, and nephrotic-range proteinuria. Laboratory testing revealed a serum creatinine level of 1.17 mg/dL, albumin level of 2.3 g/dL, and serum C3 level of 125 mg/dL (range 90-180 mg/dL). The results of the renal biopsy were consistent with DDD without C3 deposition. After 6 weeks of steroid therapy, the nephrotic syndrome completely resolved. The follow-up renal biopsy showed a significant reduction in mesangial proliferation and disappearance of electron-dense deposits in the GBM.

• 대한전자공학회논문지SD
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• 제42권1호
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• pp.33-38
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• 2005

파장 고정된 Fabry-Perot 레이저를 사용하여 경제적인 고밀도 WDM-PON의 구현 가능성을 검증하였다. 중앙기지국에서 주입된 비간섭성광에 파장 고정된 Fabry-Perot 레이저를 이용하여 50 GHz 채널 간격의 파장분할 다중화된 4×622 Mb/s 상향신호를 30 km의 광섬유를 통해 성공적으로 전송하였다. 파장 고정된 Fabry-Perot 레이저 출력의 비팅 잡음 특성을 분석하여 Fabry-Perot 레이저가 주입되는 비간섭성 광의 강도 잡음을 억제함을 보였고, 이로 인해 50 GHz 채널 간격의 고밀도 WDM 전송이 가능함을 보였다.

• 한국멀티미디어학회논문지
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• 제21권5호
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• pp.571-582
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• 2018

Recently, development of deep learning has shown better image classification result than human. According to recent research, a hidden layer of deep learning is deeper, and a preservation of extracted features shows good results. However, in the case of general images, the extracted features are clear and easy to sort. This study aims to classify plant leaf images. This plant leaf image has high similarity in each image. Since plant leaf images have high similarity not only between images of different species but also within the same species, classification accuracy is not increased by simply extending the hidden layer or connecting the layers. Therefore, in this paper, we tried to improve the hidden layer of the algorithm called DenseNet which shows the recent excellent classification results, and compare the results of several different modified layers. The proposed method makes it possible to classify plant leaf images collected in a natural environment more easily and accurately than conventional methods. This results in good classification of plant leaf image data including unnecessary noise obtained in a natural environment.

• Smart Structures and Systems
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• 제16권4호
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• pp.607-621
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• 2015

Wireless sensor technology has been opened up numerous opportunities to advanced health and maintenance monitoring of civil infrastructure. Compare to the traditional tactics, it offers a better way of providing relevant information regarding the condition of building structure health at a lower price. Numerous domestic buildings, especially longer-span buildings have a low frequency response and challenging to measure using deployed numbers of sensors. The way the sensor nodes are connected plays an important role in providing the signals with required strengths. Out of many topologies, the dense and sparse topologies wireless sensor network were extensively used in sensor network applications for collecting health information. However, it is still unclear which topology is better for obtaining health information in terms of greatest components, node's size and degree. Theoretical and computational issues arising in the selection of the optimum topology sensor network for estimating coverage area with sensor placement in building structural monitoring are addressed. This work is an attempt to fill this gap in high-rise building structural health monitoring application. The result shows that, the sparse topology sensor network provides better performance compared with the dense topology network and would be a good choice for monitoring high-rise building structural health damage.

• 한국광학회지
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• 제14권4호
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• pp.351-354
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• 2003

본 논문에서는 0.8bit/s/Hz의 높은 대역효율을 얻을 수 있는 12.5GHz채널 간격의 양방향 초고밀도 파장분할다중화(UD-WDM: ultra-dense wavelength division multiplexing) 광채널을 80 km의 단일 모드 광섬유로 전송하였다. 초고밀도 WDM 시스템에서 요구되는 광채널 주파수의 안정화를 위해 BFL(beat-frequency-locking) 기술을 이용하였으며, 실험을 통하여 $\pm$200MHz 이내로 광채널을 안정화 시킬 수 있음을 보였다. 특히, 다수개의 비트 주파수 변별과 높은 주파수 변별력을 확보하기 위하여 RF 스펙트럼 분석기를 이용하였다. BFL 기술이 적용된 채널간격 12.5 GHz 양방향 광채널의 전송 패널티는 단방향 전송과 비교시 단지 0.3dB이었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4108-4122
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• 2016

To address challenges of an unprecedented growth in mobile data traffic, the ultra-dense network deployment is a cost efficient solution to off-load the traffic over other small cells. However, the real traffic is often much lower than the peak-hour traffic and certain small cells are superfluous, which will not only introduce extra energy consumption, but also impose extra interference onto the radio environment. In this paper, an elastic energy efficient cell management scheme is proposed based on flow scheduling among multi-layer ultra-dense cells by a SDN controller. A significant power saving was achieved by a cell-level energy manager. The scheme is elastic for energy saving, adaptive to the dynamic traffic distribution in the office or campus environment. In the end, the performance is evaluated and demonstrated. The results show substantial improvements over the conventional method in terms of the number of active BSs, the handover times, and the switches of BSs.