• Anatomy and Cell Biology
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• 제51권4호
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• pp.299-301
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• 2018

Killian-Jamieson diverticulum is a permanent protrusion of anterolateral proximal esophagus through anatomically weak muscular gap, known as Killian-Jamieson area, into adjacent area. During a routine educational dissection, we found a well-defined lateral diverticulum just inferior to the transverse fibers of the cricopharyngeus muscle in a Korean male cadaver. It had a dimension of $1.8{\times}1.4{\times}1.0cm$ with two types of epithelial cells, stratified squamous and simple cuboidal to low-columnar epithelium, and attenuated and haphazardly arranged muscle fibers. No epithelial dysplasia or malignant transformation was identified except ulcerative changes. Although Killian-Jamieson diverticulum is a very rare disease, clinicopathological aspects should be considered.

• ETRI Journal
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• 제44권1호
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• pp.125-134
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• 2022

Visible light communication (VLC) systems incorporate ambient lighting and wireless data transmission, and the experienced channel in indoor VLC is a major topic that should be examined for reliable communication. In this study, it is realized that multiple transmitters in classical alignment are the forceful factors for channel characteristics. In the frequency band, fluctuations with sudden drops are observed, where the fluctuation shape is related to the source layout and receiver location. These varying frequency-selective channels need solutions, especially for mobile users, because sustained channel estimation and equalization are necessary as the receiver changes its location. It is proven that using light-emitting diodes (LEDs) with highly directional beams as sources or using a detector with a narrow field of view (FOV) in the receiver may help partially alleviate the problem; the frequency selectivity of the channel reduces in some regions of the room. For flat fading channel characteristics all over the room, LEDs should be aligned in hexagonal cellular structure, and detector FOV should be arranged according to the cell dimension outcomes.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 추계학술발표대회
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• pp.733-736
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• 2007

최근 생명 공학 기술의 발달로 마이크로 단위의 실험이 가능해지고 하나의 칩상에 수 만개의 유전자들의 발현 양상을 보다 쉽게 관찰할 수 있게 되었다. DNA 칩 기술에 의해 얻어지는 마이크로어레이(microarray) 데이터는 세포나 조직 내의 유전자 발현도(expression level)를 측정한 것으로 질병 진단이나 유전자 기능 예측 등에 이용되고 있다. 본 논문에서는 대량의 시계열 마이크로어레이 데이터 분석을 위해 효율적으로 데이터의 차원을 판단하는 점진적 주성분 분석을 이용하여 데이터의 차원을 축소 한다. 제안된 방법은 실제 시계열 마이크로어레이 데이터인 yeast cell cycle 데이터에 적용되었고, 데이터 차원 축소에 대한 효율성을 검증하기 위해 클러스터링을 수행하였다. 그 결과 데이터를 축소하여 클러스터링을 수행한 경우 학습 성능이 향상 된 결과를 보였다.

• 종양간호연구
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• 제1권1호
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• pp.32-43
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• 2001

High risk breast cancer patients receive aggressive treatments such as APBSCT in order to prevent the recurrence. These treatments take a long time and decrease the quality of life of patients as a result. The purpose of this study is to examine when the changes of quality of life are dramatic in general and in specific dimension. This is a time series study of two types of treatment groups, in which 15 patients were treated by chemotherapy only and nine patients by auto-peripheral blood stem cell transplantation. Subjects were in this study were stage III and above of breast cancer. Data were collected from April 1999 to April 2000 with the 3 month-interval starting after 3rd cycle of chemotherapy. Data were collected 3 times ; treatment period, treatment finishing period and 3 months later after the treatment. Ferrell's QOL instrument was used which had been developed for the breast cancer patients in 1989. Repeated Measure ANOVA was used to examine differences of quality of life at 3 points of time respectively. As a result, average age was 43.29 years (4.38yrs) and the number of married person was 22(91.7%). Scores of quality of life were 5.45 at 1st period after 3rd cycle of chemotherapy, 5.17 after treatment, 5.10 at 3 months later after treatment and difference of quality of life was decreased according to period of treatment (P=.085). Only the psychological dimension of the quality of life showed the significant difference (P=.045). Two different treatment groups showed a difference of quality of life at 3 month later after treatment. In conclusions, high risk breast cancer patients showed the decreased quality of life related to treatment up to 3 months later of treatment. Subjects who received APBSCT returned to the normal quality of life more rapidly than those who received chemotherapy. Psychological nursing intervention was needed during the whole period of treatment.

• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.280-285
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• 2015

대용량 다중 송신 다중 수신 안테나 환경에서 정합 필터 송신기는 다중 사용자 하향 링크 전송 용량(capacity)을 달성하는 방법으로 알려져 있다. 그러나 기지국이 유한 개수의 대용량 안테나를 장착한 경우 정합 필터는 다중 사용자 하향링크 전송 용량을 제공할 수 없다. 본 논문에서는 유한 대용량 안테나를 갖춘 기지국이 낮은 신호 대 잡음비의 다수의 셀 경계 영역 사용자를 지원할 경우, 효율적 연산 복잡도로 전송 용량을 최대화하는 두 단계 선형 송수신기 설계 방법을 제안한다. 정합 필터로 구성된 첫째 단계 프리코더는 유효 채널 dimension 을 줄이면서 동시에 빔포밍 이득을 통해 수신 신호 대 잡음 비를 개선한다. 그리고 평균 자승 오류율 최소화 기법을 통해 전송 용량을 최대화하는 둘째 단계 선형 송수신기를 구한다. 시뮬레이션과 분석을 통해 전송 용량과 연산 복잡도 면에서 제안하는 방법이 우수함을 보인다.

• 한국정보통신학회논문지
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• 제25권5호
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• pp.685-690
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• 2021

본 논문에서는 하향링크 비직교 다중 접속 시스템에서 최소 데이터 전송률을 만족하며 데이터 전송률의 총합을 최대화 할 수 있는 딥러닝 기반의 송신 전력 제어 기법을 제안한다. 하향링크 비직교 다중 접속 시스템에서 사용자가 위치한 셀 이외의 기지국으로부터 발생할 수 있는 동일 채널 간섭을 고려하고, 시스템 피드백 오버헤드를 줄이기 위하여 사용자는 채널 상태 정보 대신에 신호 대 간섭 및 잡음비 정보를 피드백 한다. 따라서 기지국은 신호 대 간섭 및 잡음비 정보만을 이용하여 송신 전력을 제어한다. 함축적 신호 대 간섭 및 잡음비 정보의 이용은 정보 차원을 감소시키는 장점은 있지만 데이터 전송률을 감소시킬 수 있는 단점이 있다. 본 논문에서는 딥러닝 기반의 학습 방식으로 이 문제를 해결하고, 딥러닝 입력의 차원을 효과적으로 축소할 경우 학습의 성능을 향상시킬 수 있음을 보여준다. 시뮬레이션을 통해서 제안된 딥러닝 기반의 송신 전력 제어 기법이 최소 데이터 전송률을 만족하며 데이터 전송률의 총합을 향상시킬 수 있음을 입증한다.

• Anatomy and Cell Biology
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• 제57권2호
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• pp.221-228
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• 2024

Although studies of the sacral corridor dimension have been reported in the European population, little attention has been paid to this issue in the Asian population. The purpose of the study is to estimate the safe dimension of the corridor to avoid neurovascular damage during the fixation of the sacral fracture. The study aimed to examine the cephalocaudal (vertical) and the anteroposterior diameter of the bony passage in the upper three sacral segments. The study further examines the effect of age and sex on corridor dimensions at different sacral levels. Three-dimensionally reconstructed sacra from computed tomography of normal subjects were included in the study. Cephalocaudal and anteroposterior diameters were measured in coronal and axial sections using Geomagic Freeform Plus software. Anteroposterior diameter of the sacral corridor at the first, second, and third sacral segments are significantly higher in males (P=0.013, 0.0011, and <0.0001, respectively). The length of the sacrum also revealed sexual dimorphism (P<0.00016). The anteroposterior diameter of the second sacral segment (ap-S2c) correlated moderately with the first sacral anteroposterior diameter (ap-S1c) (R=0.519, P<0.001). The ap-S2c exhibited a moderate correlation to the third sacral segment (ap-S3c) (R=0.677, P<0.001). The sacral corridor at the level of S1 has the largest cephalocaudal (18.25 mm) and anteroposterior diameter (17.11 mm). Placement of the screw in the first sacral corridor may avoid damage to the neurovascular bundle during the fixation of the sacral fracture.

• 대한치과보철학회지
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• 제41권3호
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• pp.300-318
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• 2003

Statement of problem: The success of implants depends on intimate and direct contact of implant material on bone tissue and on functional relationship with soft tissue contact. Creation and maintenance of osseointegration depend on the understanding of the tissue's healing, repairing, and remodeling capacity and these capacities rely on cellular behavior. Altering the surface properties can modify cellular responses such as cell adhesion, cell motility, bone deposition, Therefore, various implant surface treatment methods are being developed for the improved bone cell responses. Purpose: The purpose of this study was to evaluate the responses of osteoblast-like cells to surface-modified titanium. Materials and Methods: The experiment was composed of four groups. Group 1 represented the electropolished surface. Group 2 surfaces were machined surface. Group 3 and Group 4 were anodized surfaces. Group 3 had low roughness and Group 4 had high roughness. Physicochemical properties and microstructures of the discs were examined and the responses of osteoblast-like cells to the discs were investigated. The microtopography was observed by SEM. The roughness was measured by three-dimension roughness measuring system. The microstructure was analyzed by XRD, AES. To evaluate cell responses to modified titanium surfaces, osteoblasts isolated from calvaria of neonatal rat were cultured. Cell count, morphology, total protein measurement and alkaline phosphatase activities of the cultures were examined. Results and Conclusion: The results were as follows 1. The four groups showed specific microtopography respectively. Anodized group showed grain structure with micropores. 2. Surface roughness values were, from the lowest to the highest, electropolished group, machined group, low roughness anodized group, and high roughness anodized group. 3. Highly roughened anodized group was found to have increased surface oxide thickness and surface crystallinity. 4. The morphology of cells, flattened or spherical, were different from each other. In the electropolished group and machined group, the cells were almost flattened. In two anodized groups, some cells were spherical and other cells were flattened. And the 14 day culture cells of all of the groups were nearly flattened due to confluency. 5. The number of attached cells was highest in low roughness anodized group. And the machined group had significantly lower cell count than any other groups(P<.05). 6. Total protein contents showed no difference among groups. 7. The level of alkaline phosphatase activities was higher in the anodized groups than electropolished and machined groups(P<.05).

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2671-2676
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• 2011

Nanocrystalline $TiO_2$ spherical particle (NP) with a dimension of 5 ${\times}$ 5.5 nm and several nanorods (NR) with different aspect ratios (diameter ${\times}$ length: 5 ${\times}$ 8.5, 4 ${\times}$ 15, 4 ${\times}$ 18 and 3.5 ${\times}$ 22 nm) were selectively synthesized by a solvothermal process combined with non-hydrolytic sol-gel reaction. With varying the molar ratio of TTIP to oleic acid from 1:1 to 1:16, the NRs in the pure anatase phase were elongated to the c-axis direction. The prepared NP and NRs were applied for the formation of nanoporous $TiO_2$ layers in dye-sensitized solar cell (DSSC). Among them, NR2 ($TiO_2$ nanorod with 4 ${\times}$ 15 nm) exhibited the highest cell performance: Its photovoltaic conversion efficiency (${\eta}$) of 6.07%, with $J_{sc}$ of 13.473 mA/$cm^2$, $V_{oc}$ of 0.640 V, and FF of 70.32%, was 1.44 times that of NP with a size of 5 ${\times}$ 5.5 nm. It was observed from the transient photoelectron spectroscopy and the incident photon to current conversion efficiency (IPCE) spectra that the $TiO_2$ films derived from NR2 demonstrate the longest electron diffusion length ($L_e$) and the highest external quantum efficiency (EQE).

• 한국자기학회지
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• 제18권3호
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• pp.103-108
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• 2008

비휘발성 메모리 분야에서 MRAM이 큰 주목을 받지 못하는 이유는 일반적인 비휘발성 메모리에 비해 기록용량이 작다는 문제를 안고 있기 때문이다. 이러한 문제는 MRAM의 일반적인 구조가 자기 효율이 떨어지는 구조를 가지고 있기 때문이다. MRAM이 고용량화 되기 위해선 한 셀의 구조가 작아져야 하는데 두 전류라인만을 이용하는 일반적인 구조에선 큰 기록 필드를 발생시킬 수 없기에 셀의 구조를 작게하는 것은 불가능하다. 본 논문에서는 MRAM의 기록층 양단에 큰 투자율을 가진 Pole을 추가한 형태의 새로운 MRAM을 제안하고 있다. 새로이 고안된 MRAM은 일반적인 MRAM에 비해 자기효율이 크게 향상 되기 때문에 큰 기록 필드를 발생시킬 수 있기 때문에 보자력이 큰 기록 층을 사용할 수 있고 이로 인해 한 셀의 사이즈를 줄일 수 있게 된다. 본 연구는 3차원 유한요소법을 사용하여 진행 되었다.