경직장 초음파검사를 이용한 정낭의 크기 측정

윤성국,구봉식,조진한,최종철,남경진,박병호,이영일 대한초음파의학회 1998 ULTRASONOGRAPHY Vol.17 No.1

Interferer Aware Multiple Access Protocol for Power-Line Communication Networks

윤성국 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

Hidden station problem can occur in power-line communication (PLC) networks. A simple solution to the problem has been proposed to use request-to-send (RTS)/clear-to-send (CTS) exchange, but this approach cannot solve the hidden station problem perfectly. This paper revisits the problem for PLC networks and designs a protocol to solve it. We first analyze the throughput performance degradation when the hidden station problem occurs in PLC networks. Then, we propose an interferer aware multiple access (IAMA) protocol to enhance throughput and fairness performances, which uses unique characteristics of PLC networks. Using the RTS/CTS exchange adaptively, the IAMA protocol protects receiving stations from being interfered with neighboring networks. Through extensive simulations, we show that our proposed protocol outperforms conventional random access protocols in terms of throughput and fairness.

복압 요실금에서 Tension-Free Vaginal Tape 수술 후 경회음부 초음파 검사의 유용성

윤성국 대한영상의학회 2005 대한영상의학회지 Vol.52 No.1

Purpose: To evaluate the usefulness of perineal ultrasonography after a tension-free vaginal tape (TVT) procedure in women with stress urinary incontinence. Materials and Methods: Thirty-four patients with stress urinary incontinence who underwent the TVT procedure were included in this study. We compared the perineal ultrasonography findings before and after the procedure. The mean age was 49 years (range: 32-75 years) and the mean follow-up time was 9.5 days (range: 5-19 days). We obtained the entire sagittal image of the bladder neck, urethra, urethrovesical junction and symphysis pubis. The posterior urethrovesical angle (PUVA) and descent of the bladder neck at rest and during stress, and the diameter of proximal urethra at rest were all evaluated. We compared these ultrasonographic changes before and after the procedure. Results: Before the TVT procedure, the PUVA was 134.7±5.9°at rest and 146.8±8.5°during stress, and the difference between PUVA at rest and during stress was 12.2±7.3°. After the TVT procedure, the PUVA significantly decreased to 125.6±7.5°at rest and 132.5±8.3°during stress, and the difference also significantly decreased to 7.0±5.0°(p<0.01). Before the procedure, the descent of the bladder neck was 17±7.0 mm, while the descent significantly decreased to 7.7±4.1 mm after the procedure (p<0.01). Before the procedure, the diameter of the proximal urethra was 5.6±1.4 mm at rest, but the diameter was 5.5±1.1 mm, without significant change, after the procedure. Conclusion: Follow-up perineal ultrasonography after the TVT procedure may be useful for evaluating changes including the PUVA, descent and appearance of the bladder neck. 목적: 복압 요실금 환자에서 tension-free vaginal tape(TVT) 수술 후 추적 경회음부 초음파검사를 시행하여 수술 전후 경회음부 초음파 검사의 유용성을 알아보고자 하였다. 대상과 방법: 복압 요실금으로 진단되어 TVT 수술을 받았던 34예를 대상으로 수술 전후에 경회음부 초음파 검사를 시행하였다. 평균 연령은 49세(32-75세)이었고 수술 후 추적 경회음부 초음파 검사 기간은 평균 9.5일(5-19일)이었다. 환자가 앙와위 자세에서 경회음부 초음파 검사를 시행하여 요도, 방광요도접합부, 방광의 기저부, 치골결합이 한 화면에 들어오도록 하여 안정시와 Valsalva법 또는 기침과 같은 긴장을 유발한 후 시상면 영상을 얻었다. 이 영상에서 후요도방광각, 방광경부의 하강거리, 그리고 안정시의 근위부 요도직경 등을 조사하였다. 이상 소견들을 술 전 그리고 술 후 경회음부 초음파 검사를 시행하여 변화를 조사하였다. 결과: TVT 수술 전 경회음부 초음파 검사에서 후요도방광각은 안정시 134.7±5.9°, 긴장시146.8±8.5°이었고, 안정시와 긴장시의 후요도방광각의 차이는 12.2±7.3°이었으며, 수술 후 추적 경회음부 초음파 검사에서 안정시 125.6±7.5°, 긴장시 132.5±8.3°이었고, 안정시와 긴장시의 차이는 7.0±5.0°로 감소되어 유의한 차이가 있었다(p<0.01). 수술 전 방광경부의 하강거리는 17±7.0 mm이었고, 수술 후에는 7.7±4.1 mm로 감소되어 유의한 차이가 있었다(p<0.01). 수술 전 근위부 요도직경은 5.6±1.4 mm이었고, 수술 후에는 5.5±1.1 mm로 유의한 차이는 없었다. 결론: TVT 수술 후 추적 경회음부 초음파 검사는 후요도방광각, 방광경부의 하강거리, 그리고 근위부 요도직경 등의 변화를 관찰하는데 유용하리라 생각한다.

스마트그리드 통신 네트워크 구성과 전력선 통신의 역할

윤성국 한국통신학회 2014 정보와 통신 Vol.31 No.11

정보통신기술과 전력에너지기술의 융합 기술인 스마트그리드는 지속 가능한 성장의 필수적인 요소이다. 스마트그리드 통신네트워크는 전력 계통 시스템이 송전, 배전, 소비자로 구분되는 것에 맞춰 세 가지로 구분된다. 본고에서는 이 세 부분에서 사용될 스마트그리드 응용 분야를 소개하고 해당 분야가 요구하는 통신 네트워크의 성능과 후보 기술에 대하여 기술하였다. 추가적으로 전력선 통신이 스마트그리드 통신 네트워크에 활용될 방안에 대하여 논의하였다.

Vertex Coloring based Slot Reuse Scheduling for Power Line Communications

윤성국 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

Power line communication (PLC) is one of the major communication technologies in smart grid since it combines good communication capability with easy and simple deployment. As a power network can be modeled as a graph, we propose a vertex coloring based slot reuse scheduling in the time division multiple access (TDMA) period for PLCs. Our objective is to minimize the number of assigned time slots, while satisfying the quality of service (QoS) requirement of each station. Since the scheduling problem is NP-hard, we propose an efficient heuristic scheduling, which consists of repeated vertex coloring and slot reuse improvement algorithms. The simulation results confirm that the proposed algorithm significantly reduces the total number of time slots.

일본의 행정구역개편

윤성국 한국정부학회 2010 Korean Association of Governmental Studies(KAGOS) Vol.22 No.1

Access Point Contention-based Distributed Scheduling in Densely Deployed Network Environments

윤성국,Jonghun Han,박세웅,Jeongkyun Yun 에스케이텔레콤 (주) 2011 Telecommunications Review Vol.21 No.5

With increasing demands for high data rate services, femtocell networks or small cell sized WLANs have emerged as promising technologies. Since each femtocell network or WLAN consists of uncoordinated subnetworks independently, interference from others can degrade overall network capacity severely. In this paper, we address the interference problem between uncoordinated Access Points (APs) and propose a distributed AP scheduling scheme in a densely deployed femtocell network. To mitigate the interference problem, our proposal focuses on sharing the time resource through AP contention while previous researches have focused on adjusting power and frequency resources. According to the contention result, a winning AP is determined to use the next time frame solely. To operate in a fully distributed manner, our proposal needs help from Mobile Nodes (MNs) and requires a new synchronous frame structure which uses special common control channels. Simulation results show our proposed scheme doubles the network capacity compared to the legacy non-contending scheme.

Homeplug AV 네트워크에서의 성능 향상을 위한 적응적 Contention Window 조절 방식

윤성국,윤정균,김병승,박세웅 한국통신학회 2008 韓國通信學會論文誌 Vol.33 No.5

Value of Diffusion Tensor Imaging of Prostate Cancer: Comparison with Systemic Prostate Biopsy

윤성국,김동원,하동호,권희진,강명진,최순섭,남경진,김정일 대한영상의학회 2011 대한영상의학회지 Vol.64 No.2

Purpose: This study was performed to evaluate the usefulness of diffusion tensor imaging (DTI) and to correlate systemic twelve biopsy in prostate cancer. Materials and Methods: Thirty-one patients with suspected prostate cancer underwent MR imaging. DTI was performed prior to a prostate biopsy. We prospectively calculated the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) value in each corresponding biopsy site. Results: Twenty-three of 31 patients had histopathologically proven adenocarcinoma. Among the 276 biopsy cores of 23 patients with prostate cancer, 109 cores showed positive results (39%). The ADC and FA value of positive cores were 1.31 ± 0.34×10^-3 mm^2/s and 0.68 ± 0.07, and those of the negative cores were 1.74 ± 0.45×10^-3 mm^2/s and 0.54 ± 0.09, respectively. Eight patients without carcinoma showed an ADC value of 1.83 ± 0.26×10^-3 mm^2/s and an FA value of 0.47 ± 0.07. The ADC and FA value of positive cores were significantly lower and higher than those of negative cores and cancer-free patients, respectively (p < 0.05). Conclusion: The ADC and FA values using DTI may provide useful diagnostic information in the differentiation of cancerous tissues, although there is overlap in some cases.

일본의 행정구역개편

윤성국 한국정부학회 2009 Korean Association of Governmental Studies(KAGOS) Vol.21 No.2