• Radiation Oncology Journal
• /
• 제35권1호
• /
• pp.39-47
• /
• 2017

Purpose: The purpose of this study was to analyze clinical outcomes from cervical cancer and stratify patients into risk groups for prognostic factors for early-stage disease. Materials and Methods: We retrospectively reviewed patients with stage IB or IIA cervical cancer treated with adjuvant radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) following primary surgery at Samsung Medical Center from 2001 to 2011. Adjuvant RT was added for patients with intermediate-risk factors, and adjuvant CCRT was performed on high-risk patients after surgery. Results: We reviewed 247 patients-149 in the high-risk group and 98 in intermediate-risk group. The median follow-up was 62 months. Loco-regional failure (LRF) alone occurred in 7 patients (2.8%), distant metastasis alone in 37 patients (15.0%) and LRF with DM in 4 patients (1.6%). The 5-year disease-free survival (DFS) and overall survival (OS) rates for both groups were 79.7% and 87.6%, respectively. In the high-risk group, the 5-year DFS and OS probabilities were 72.5% and 81.9%, respectively. Histologic type, pathologic tumor size, and the number of pelvic lymph node (PLN) metastasis were significant prognostic factors for DFS and OS. We suggest a scoring system (0-3) using these prognostic factors to predict poor prognosis in high-risk patients. Using this system, patients with higher scores have higher recurrence and lower survival rates. Conclusion: In the high-risk cervical-cancer group who received primary surgery and adjuvant CCRT, non-squamous type, large tumor size and the number of PLN metastasis were significant prognostic factors, and the number of these factors was associated with survival rates.

• 한국정보과학회논문지:정보통신
• /
• 제33권6호
• /
• pp.428-437
• /
• 2006

최근 몇년간 무선 애드-흑 라우팅을 위한 많은 스킴들이 광범위하게 연구되었다. 위치기반 라우팅은 애드-혹 라우팅의 한 부류로써, 각 중계노드는 자신 및 목적지, 그리고 이웃노드들의 위치정보에 기반하여 독립적으로 다음-홉(next-hop) 노드를 선택한다. 이러한 위치기반 라우팅은 라우팅 상태 정보를 유지해야 하는 부담이 없기 때문에 대규모 애드-혹 망에 적합하다. 그러나, 위치기반 라우팅은 발신지와 목적지 사이에 빈공간(void)이 존재할 경우 매우 긴 우회 경로를 선택하는 문제를 안고 있다. 이 문제를 해결하기 위해, 본 논문에서는 랜드마크를 이용하는 위치기반 라우팅 방안(GLR)을 제안한다. GLR은 랜드마크(landmark)라고 불리우는 중계노드를 재귀적으로 발견하고 랜드마크 사이를 연결하는 서브패스(sub-path)를 구성한다. 다양한 망 위상에서 행해진 시뮬레이션 결과를 통해서, 제안된 방안(GLR)이 위치기반 라우팅의 성능을 크게 향상시킬 수 있음을 보인다.

• 정보처리학회논문지C
• /
• 제15C권3호
• /
• pp.213-220
• /
• 2008

이동성을 가진 다수의 노드들로 구성된 MANET에서는 네트워크 토폴로지의 빈번한 변화에 효과적으로 대응할 수 있는 온디맨드 방식의 라우팅 프로토콜이 주로 사용된다. 기존의 AODV 라우팅 기법에서 목적지 노드가 local repair 지역을 벗어나서 이동하고 있을 때, local repair 방법은 불필요한 시간지연을 가져다 줄 뿐이며, 이러한 local repair 방법으로 인한 시간지연은 전체적인 라우팅 경로의 설정시간을 오래 걸리게 할 뿐 아니라, 생성된 데이터 패킷의 손실을 증가시키는 문제를 가져온다. 따라서 본 논문에서는 목적지 노드까지의 경로 단절시 출발지 노드로 가서 경로 재탐색을 하지 않고 이웃 노드의 순서번호를 이용하여 직접 경로설정을 위한 동작을 할 경우 보다 신속하게 경로를 설정할 수 있으며, 데이터의 패킷 손실도 줄여 줄 수 있는 AODV 기반 효율적인 라우팅 프로토콜인 NAODV 프로토콜을 제안하였다. NS-2를 이용한 시뮬레이션 결과는 제안한 기법이 기존의 AODV 보다 패킷 전달비율, 지연시간 측면에서 향상된 성능을 제공함을 보여준다. 또한 노드의 이동 속도가 빠르고 대형망으로 갈수록 더욱 효과적인 방법임을 확인하였다.

• Smart Structures and Systems
• /
• 제6권5_6호
• /
• pp.561-578
• /
• 2010

This study proposes a multi-level damage localization strategy to achieve an effective damage detection system for civil infrastructure systems based on wireless sensors. The proposed system is designed for use of distributed computation in a wireless sensor network (WSN). Modal identification is achieved using the frequency-domain decomposition (FDD) method and the peak-picking technique. The ASH (angle-between-string-and-horizon) and AS (axial strain) flexibility-based methods are employed for identifying and localizing damage. Fundamentally, the multi-level damage localization strategy does not activate all of the sensor nodes in the network at once. Instead, relatively few sensors are used to perform coarse-grained damage localization; if damage is detected, only those sensors in the potentially damaged regions are incrementally added to the network to perform finer-grained damage localization. In this way, many nodes are able to remain asleep for part or all of the multi-level interrogations, and thus the total energy cost is reduced considerably. In addition, a novel distributed computing strategy is also proposed to reduce the energy consumed in a sensor node, which distributes modal identification and damage detection tasks across a WSN and only allows small amount of useful intermediate results to be transmitted wirelessly. Computations are first performed on each leaf node independently, and the aggregated information is transmitted to one cluster head in each cluster. A second stage of computations are performed on each cluster head, and the identified operational deflection shapes and natural frequencies are transmitted to the base station of the WSN. The damage indicators are extracted at the base station. The proposed strategy yields a WSN-based SHM system which can effectively and automatically identify and localize damage, and is efficient in energy usage. The proposed strategy is validated using two illustrative numerical simulations and experimental validation is performed using a cantilevered beam.

• 한국자원식물학회지
• /
• 제29권4호
• /
• pp.504-510
• /
• 2016

본 연구는 중간 신육형 직립 초형 동부 계통의 파종기 이동이 생태반응과 생육 및 수량에 미치는 영향을 구명하고자 전남 나주(위도 35° 04' N, 경도 126° 54' E)에서 2013년과 2014년에 수행하였다. 시험계통으로 전남1호와 전남2호(옥당)를 이용하여 4월 중순부터 8월 중순까지 1개월 간격으로 5회 파종하였다. 출현일수는 4월 중순 파종에서 12일로 길었고, 기타 파종기에서는 5∼3일이었다. 개화일수는 4월 중순부터 7월 중순까지는 파종기가 지연됨에 따라 짧아지다 8월 중순 파종에서 길어졌다. 즉, 4월 중순 파종에서 62일 내외로 가장 길었고, 7월 중순 파종에서 35일로 가장 짧았다. 개화시에서 수확기까지의 소요일수는 4월 중순부터 7월 중순 파종에서 17∼15일로 짧았으나, 8월 중순 파종에서는 24일로 긴 편이었다. 경장은 5월 중순과 6월 중순 파종에서 긴 편이었고, 화경장은 4월 중순 파종에서 긴 편이었으며, 주경절수는 7월 중순 파종, 분지수는 4월 중순 파종에서 많았다. 전남1호와 전남2호(옥당)의 10 a당 수량은 4월 중순 파종에서 각각 199, 211 ㎏로 가장 많았고, 다음으로 7월 중순 파종에서 각각 191, 195 ㎏로 많았다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권2호
• /
• pp.678-690
• /
• 2014

The current networks do not disclose information about a management domain due to scalability, manageability and commercial reasons. Therefore, it is very hard to calculate an optimal path to the destination. Also, due to poor information sharing, if an error occurs in the intermediate path, it is very difficult to re-search the path and find the best path. Hence, to manage each domain more efficiently, an architecture with top-level path computation node which can obtain information of separate nodes are highly needed This study aims to investigate a federation of a united network around NRN(National Research Network) that could allow resource sharing between countries and also independent resource management for each country. Considering first the aspects that can be accessed from the perspective of a national research network, ICE(Information Control Element) and GFO(Global Federation Organizer)-based architecture is designed as a top-level path computation element to support traffic engineering and applied to the multi-domain network. Then, the federation for the independent management of resources and resource information sharing among national research networks have been examined.

• Computational Structural Engineering : An International Journal
• /
• 제1권2호
• /
• pp.89-96
• /
• 2001

A study on the topology optimization of a Hard-Disk-Driver(HDD) actuator arm is presented. The purpose of the present wert is to increase the natural frequency of tole first lateral mode of the HDD actuator arm under the constraint of total moment of inertia, so as to facilitate the position control of the high speed actuator arm. The first lateral mode is an important factor in the position control process. Thus the topology optimization for 2-D model of the HDD actuator arm is considered. A new objective function corresponding to multieigenvalue optimization is suggested to improve the solution of the eigenvalue optimization problem. The material density of the structure is treated as the design variable and the intermediate density is penalized. The effects of different element types and material property functions on the final topology are studied. When the problem is discretized using 8-node element of a uniform density, tole smoothly-varying density field is obtained without checker-board patterns incurred. AS a result of 7he study, an improved design of the HDD actuator arm is suggested. Dynamic characteristics of the suggested design are compared computationally with those of the old design. With the same amount of the moment of inertia, the natural frequency of the first lateral mode of the suggested design is subsequently increased over the existing one.

• 대한전자공학회논문지SD
• /
• 제38권11호
• /
• pp.804-809
• /
• 2001

본 논문에서는 광 WDM 멀티홉 네트워크에서 필요한 파장 채널 수를 줄이기 위하여 격행 연결 이중층 셔플넷 방식을 이용한 효과적인 채널 공유 방식과 이를 위한 라우팅 알고리즘을 제안한다. 채널 공유 방법은 2P개의 노드들이 하나의 채널을 공유하게 하는 방법으로써 전체적으로 필요한 파장 수가 기존의 방법에 비하여 줄어들게 된다. 각 열에 있는 노드는 두 개씩 짝을 이루게 하여 각각의 쌍의 번호를 p-진수로 계산하고, 각 쌍의 위에 위치한 노드에는 2-진수의 0을 첨가하고 아래에 위치한 노드에는 2-진수의 1을 첨가하여 각 노드에 대한 주소를 결정한다. 이와 같이 정해진 주소를 이용하여 효과적으로 패킷을 중계하도록 알고리즘을 제안하고 (4, 2) 토폴로지에서의 경로설정 방법을 예를 들어 설명한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권2호
• /
• pp.271-287
• /
• 2013

We propose a new multipath-based reliable routing protocol on MANETs, Multipath-based Reliable routing protocol with Fast-Recovery of failures (MRFR). For reliable message transmission, MRFR tries to find the most reliable path between a source and a destination considering the end-to-end packet reception reliability of the routes. The established path consists of a primary path that is used to transmit messages, and the secondary paths that are used to recover the path when detecting failures on the primary path. After establishing the path, the source transmits messages through the primary path. If a node detects a link failure during message transmission, it can recover the path locally by switching from the primary to the secondary path. By allowing the intermediate nodes to locally recover the route failure, the proposed protocol can handle the dynamic topological change of the MANETs efficiently. The simulation result using the QualNet simulator shows that the MRFR protocol performs better than other protocols in terms of the end-to-end message delivery ratio and fault-tolerance capability.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권4호
• /
• pp.800-818
• /
• 2013

Supporting video streaming over multi-hop wireless networks is particularly challenging due to the time-varying and error-prone characteristics of the wireless channel. In this paper, we propose a joint optimization scheme for video streaming over multi-hop wireless networks. Our coding scheme, called Joint Source/Network Coding (JSNC), combines source coding and network coding to maximize the video quality under the limited wireless resources and coding constraints. JSNC segments the streaming data into generations at the source node and exploits the intra-session coding on both the source and the intermediate nodes. The size of the generation and the level of redundancy influence the streaming performance significantly and need to be determined carefully. We formulate the problem as an optimization problem with the objective of minimizing the end-to-end distortion by jointly considering the generation size and the coding redundancy. The simulation results demonstrate that, with the appropriate generation size and coding redundancy, the JSNC scheme can achieve an optimal performance for video streaming over multi-hop wireless networks.