• Title/Summary/Keyword: 경로 안정성

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친환경 CuInS2 나노입자가 고분자 박막층 안에 분산된 유기 쌍안정성 소자의 메모리 특성

  • Ju, Ang;Yun, Dong-Yeol;Kim, Tae-Hwan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.393.1-393.1
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    • 2014
  • 유기물/무기물 나노복합체를 이용하여 제작한 유기비휘발성 메모리 소자는 간단한 공정과 플렉서블기기 응용 가능성 때문에 많은 연구가 진행되고 있다. 유기물/무기물 나노복합체를 사용하여 제작한 비휘발성 메모리 소자의 전기적 성질에 대한 연구는 많이 진행되었으나, Poly (N-vinylcarbazole) (PVK) 박막 내부에 분산된 친환경 CuInS2 (CIS) 나노입자를 이용하여 제작한 유기 쌍안정 소자의 메모리 특성에 대한 연구는 미미한 실정이다. 본 연구에서는 PVK박막층안에 분산된 CIS나노입자를 사용한 메모리 소자를 제작하여 전기적 특성에 대하여 연구하였다. 화학적으로 합성 된 CIS 나노입자를 톨루엔에 용해되어있는 PVK에 넣고 초음파 교반기를 사용하여 두 물질을 고르게 섞었다. 전극이 되는 indium-tin-oxide 가 성장된 유리 기판 위에CIS 나노입자와 PVK가 섞인 용액을 스핀코팅 한 후, 열을 가해 용매를 제거하여 CIS 나노입자가 PVK에 분산되어 있는 나노복합체 박막을 형성하였다. 형성된 나노복합체 박막 위에 상부 전극으로 Al을 열증착하여 비휘발성 메모리 소자를 제작하였다. 제작된 소자의 전류-전압 측정 결과는 메모리 특성을 나타내었으며, CIS 나노입자를 포함하지 않은 소자와의 비교를 통해 CIS나노입자가 비휘발성 메모리 소자에서 메모리 특성을 나타내게 하는 역할을 확인하였다. 전류-시간 측정 결과 소자의 ON/OFF 전류 비율이 시간에 따라 큰 변화 없이 1,000 회 이상 지속적으로 유지함을 관찰함으로써 소자의 전기적 기억 상태 안정성을 확인하였다.

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A Study on the Hydraulic Stability of Soil Mixed with Bio-Polymer (바이오 폴리머가 혼합된 토양의 수리안정성에 관한 연구)

  • Lee, Du Han;Kim, Myounghwan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.270-270
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    • 2019
  • 미생물의 부산물인 바이오 폴리머와 혼합된 토양의 수리안정성이 증가하는 효과를 시험하기 위하여 안동 하천실증연구센터 실규모 수로에 물관리연구사업의 "친환경 신소재를 이용한 고강도 제방 기술 개발" 연구과제에서 개발 중인 바이오 폴리머와 혼합된 토양을 도포하여 시험구를 만들고 수리안정성에 관한 실험을 수행하였다. 실험에서는 바이오 폴리머와 마사토를 혼합하여 사용하였으며, 바이오 폴리머와 혼합된 토양은 도포 두께, 식생 유무 등에 따라 구분하였다. 실험은 물의 소류력과 토양손실과의 관계를 통하여 수리안정성을 평가하는 ASTM 시험법을 준용하여 진행하였고, 실험 결과를 통하여 새로 개발된 바이오 폴리머가 토양의 수리안정성을 증가 시키는 것을 확인 할 수 있었다. 특히 바이오 폴리머가 도포된 토양에 식생이 활착되었을 경우 강한 소류력이 발생하는 흐름에서도 토양 손실이 매우 적게 발생하였으며, 이를 통하여 개발된 바이오 폴리머의 성능을 일부 확인 할 수 있었다.

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An Efficient Routing Protocol Considering Path Reliability in Cognitive Radio Ad-hoc Networks (인지 무선 애드혹 네트워크에서 경로 신뢰성을 고려한 효율적인 라우팅 기법)

  • Choi, Jun-Ho;Yoo, Sang-Jo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.11
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    • pp.730-742
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    • 2014
  • In the case of On-demand routing protocol in cognitive radio ad-hoc networks, broadcasting of control packets may occur common control channel overload and packet collisions during the routing procedure. This situation is to increase the overhead of path finding and also limited to find the accurate and reliable path. Since reliable channel and path finding is restricted, path life time is shorten and path reliability is reduced. In this paper, we propose a new routing algorithm that reduces control channel overhead and increases path life time by considering the probability of appearance of primary user and channel status of neighbor nodes. Each node performs periodic local sensing to detect primary user signal and to derive primary user activity patterns. The probability of primary appearance on the current channel and the channel status can be obtained based on the periodic sensing. In addition, each node identifies the quality of the channel by message exchange through a common channel with neighbor nodes, then determines Link_Levels with neighbor nodes. In the proposed method, the Link Level condition reduces the number of control messages that are generated during the route discovery process. The proposed method can improve path life time by choosing a path through Path_Reliability in which stability and quality are weighted depending on the location. Through simulation, we show that our proposed algorithm reduces packet collisions and increases path life time in comparison with the traditional algorithm.

Predicted Hydraulic Behavior in In-Situ Soil Slope Using the Path-Dependent Soil Water Characteristic Curve (불포화 함수특성의 경로의존성을 고려한 현장사면 수리거동 예측)

  • Park, Hyun Su;Song, Young-Suk;Park, Seong-Wan
    • Journal of the Korean Geotechnical Society
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    • v.33 no.4
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    • pp.25-34
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    • 2017
  • The soil-water characteristics is the most important state parameter for understanding changes in suction and water contents of unsaturated soil slopes. In the field, the hysteretic behaviors of drying and wetting soil-water characteristic curve are real and the adoption of path-dependent suction-water content is needed to predict the hydro-mechanical analysis of unsaturated soils. In this study, in-situ monitored hydraulic behavior of various soil slopes are compared with the data from numerical analysis with the laboratory soil water characteristic curve. Then, the verifications are performed based on the field monitored data respectively. Therefore, the use of path-dependent soil-water characteristic curves could be more rational for design and analysis of unsaturated soil slopes under rainfall conditions.

Enhanced IP Multicast Provisioning Scheme Based on HA Routing (HA 라우팅 기반의 개선된 멀티캐스트 제공 방안)

  • 김인경;하정락;현은희;김상하
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10c
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    • pp.433-435
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    • 2001
  • IETF Mobile IP는 이동 컴퓨팅 환경에서 IP 멀티캐스트를 지원하기 위한 메커니즘으로 HA 기반 라우팅과 FA 기반 라우팅을 간략히 언급하고 있다. FA 기반 라우팅의 경우, 단말기 이동 시 멀티캐스트 트리를 재구성하는 오버헤드가 존재하는 단점이 있다. 반면. HA 기반 라우팅의 경우, 단말기 이동시 경로 최적화가 이루어지지 않는 단점에도 불구하고. 멀티캐스트 트리 수정에 대한 오버헤드가 존재하지 않은 장점이 있다. 이러한 장점은 망의 안정성을 놓일 수 있기 때문에 많은 연구에서 HA 기반 라우팅을 채택하고 있다. 하지만, 기존의 HA 기반 라우팅 방법에서 가장 큰 장애 요소는 터널링 집중화 현상이며, 이를 해결하기 위해 Mobile Multicast (MOM) 등에서 정성적인 방법을 제안하고 있지만, 구체적인 프로토콜이 없으며 모든 HA들이 관여하는 복잡도로 인해 실제로 망에 배치되는 데 한계성을 가진다. 본 논문에서는 현재의 Mobile IP 메시지의 간단한 확장과 FA메 멀티캐스팅을 위한 기능을 첨가하여. 터널링 집중화 현상을 해결하는 프로토콜을 제안하고자 한다. 제안되는 프로토콜은 현재의 모든 IP 멀티캐스트를 수용하고, Mobile IP와의 호환성을 유지한다.

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Trajectory Planning and Fuzzy Controller Design of a Re-entry vehicle on Approach and Landing phase (재진입 비행체의 진입 및 착륙단계 경로 생성 및 퍼지제어기 설계)

  • Min, Chan-Oh;Jo, Sung-Jin;Lee, Dae-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.2
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    • pp.150-159
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    • 2010
  • The approach and landing phase of a re-entry vehicle is composed of Steep Glideslope phase, Circular Flare phase, Flare Maneuver phase. The trajectory planning algorithm with geometric parameters is studied in this paper for on-board trajectory planning. This algorithm generate reference trajectory rapidly considering safe landing of re-entry vehicle. In this paper, the Mamdani Fuzzy PD type controller for longitudinal and lateral control is designed which has robustness of nonlinear system. In addition, the simulation is performed including initial downrange and crossrange errors, and the results shows that the proposed fuzzy logic controller has good performance.

A Study on Rainfall-induced Erosion of Land Surface on Reinforced Slope Using Soil Improvement Material (지반 개량재에 의한 보강사면의 강우시 표면침식에 관한 연구)

  • Kim, You-Seong;Kim, Jae-Hong;Bhang, In-Hwang;Seo, Se-Gwan
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.49-59
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    • 2013
  • Heavy rainfall intensity may cause shallow slope failures and debris flow by rill erosion and scour on land surface. The paper represents the difference between native soil (weathered soil) and reinforced soil, which is mixed by hardening agent with flyash as main material, for investigating experimental findings of rill erosion and erosion. Results obtained from artificial rainfall simulator show that erosion rate of reinforced soil mixed with hardening agent is reduced by 20% because an amount of eroded soil on slope surface is inversely proportional to the increase of soil strength. For example, rainfall of 45mm (at the elapsed time of 25mins in rainfall intensity of 110mm/hr) triggers rill erosion on native soil surface, but the rill erosion on reinforced soil surface does not even occur at 330mm rainfall (at the elapsed time of 3hrs in rainfall intensity of 110mm/hr). As a result of slope stability analysis, it was found that the construction method for reinforced soil surface would be more economical, easy and fast construction technology than conventional reinforcement method.

Clinical outcome in relation to stability of longitudinal meniscal tear associated with anterior cruciate ligament rupture (전방 십자인대 파열에 동반된 반월상 연골판 종파열의 파열부위 안정성에 따른 치료 결과)

  • Seo, Seung-Suk;Kim, Chang-Wan;Kim, Jin-Seok;Kim, Jeon-Gyo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.9 no.2
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    • pp.91-97
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    • 2010
  • Purpose: The purpose of this study was to evaluate the results of treatment for longitudinal meniscal tear in ACL rupture patients by clinical evaluation and $2^{nd}$ look arthroscopy. Materials and Methods: Among the patients who underwent surgery due to ACL rupture and longitudinal meniscal tear between 2002~2009, 32 patients were selected for the study. The patients were devided into three groups; group 1 had repair, group 2 had partial menisectomy due to impossible to repair, group 3 had conservative treatment due to stable meniscus. Comparative retrospective analysis was applied with KT 1000 arthrometer, Lysolm' score, Tegner activity score, IKDC subjective score, and $2^{nd}$ look arthroscopy. Results: Lysolm' score, Tegner activity score, IKDC subjective score showed no statistical difference in all three groups. KT-1000 side to side difference improved from 6.2, 6.15, 6.38 before surgery to 2.56, 2.49, 2.58 after surgery in group 1, 2, and 3, respectively. In group 1, second-look arthroscopy revealed complete healing in 12 patients, incomplete healing without any clinical symptoms in 2, and healing failure in 1. In group 2, second-look arthroscopy showed partial regeneration on margin of meniscectomy. In group 3, second-look arthroscopy revealed complete healing in 2 patients, while 4 showed incomplete healing so that have repaired. Conclusion: In the study, the outcome was better when the stable longitudinal meniscal tear on posterior horn with ACL rupture had active treatment.

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Automatic Stair-Climbing Algorithm of the Planetary Wheel Type Mobile Robot in Nuclear Facilities (원자력시설내에서의 유성차륜형 이동로보트의 자동계단 승월기법)

  • Kim, Byung-Soo;Kim, Seung-Ho;Lee, Jongmin
    • Nuclear Engineering and Technology
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    • v.27 no.5
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    • pp.661-669
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    • 1995
  • A mobile robot, named KAEROT, has been developed for inspection and maintenance operations in nuclear facilities. The main feature of locomotion system is the planetary wheel assembly with small wheels. This mechanism has been designed to be able to go over the stairs and obstacles with stability. This paper presents the inverse kinematic solution that is to be operated by remote control. The automatic stair climbing algorithm is also proposed. The. proposed algorithms generates the moving pathes of small wheels and calculates the angular velocity of 3 actuation wheels. The results of simulations and experiments are given for KAEROT peformed on the irregular stairs in laboratory. It is shown that the proposed algorithm provides the lower inclination angle of the robot body and increases its stability during navigation.

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Deep Learning Research on Vessel Trajectory Prediction Based on AIS Data with Interpolation Techniques

  • Won-Hee Lee;Seung-Won Yoon;Da-Hyun Jang;Kyu-Chul Lee
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.3
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    • pp.1-10
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    • 2024
  • The research on predicting the routes of ships, which constitute the majority of maritime transportation, can detect potential hazards at sea in advance and prevent accidents. Unlike roads, there is no distinct signal system at sea, and traffic management is challenging, making ship route prediction essential for maritime safety. However, the time intervals of the ship route datasets are irregular due to communication disruptions. This study presents a method to adjust the time intervals of data using appropriate interpolation techniques for ship route prediction. Additionally, a deep learning model for predicting ship routes has been developed. This model is an LSTM model that predicts the future GPS coordinates of ships by understanding their movement patterns through real-time route information contained in AIS data. This paper presents a data preprocessing method using linear interpolation and a suitable deep learning model for ship route prediction. The experimental results demonstrate the effectiveness of the proposed method with an MSE of 0.0131 and an Accuracy of 0.9467.