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Improving the Performance of AODV(-PGB) based on Position-based Routing Repair Algorithm in VANET
( Sungdae Jung ),( Sangsun Lee ),( Hyunseo Oh ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.6
Vehicle ad hoc networks (VANET) are one of the most important technologies to provide various ITS services. While VANET requires rapid and reliable transmission, packet transmission in VANET is unstable because of high mobility. Many routing protocols have been proposed and assessed to improve the efficiency of VANET. However, topology-based routing protocols generate heavy overhead and long delay, and position-based routing protocols have frequent packet loss due to inaccurate node position. In this paper, we propose a position-based routing repair algorithm to improve the efficiency of VANET. This algorithm is proposed based on the premise that AODV (-PGB) can be used effectively in VANET, if the discovery, maintenance and repair mechanism of AODV is optimized for the features of VANET. The main focus of this algorithm is that the relay node can determine whether its alternative node exits and judge whether the routing path is disconnected. If the relay node is about to swerve from the routing path in a multi-hop network, the node recognizes the possibility of path loss based on a defined critical domain. The node then transmits a handover packet to the next hop node, alternative nodes and previous node. The next node repairs the alternative path before path loss occurs to maintain connectivity and provide seamless service. We simulated protocols using both the ideal traffic model and the realistic traffic model to assess the proposed algorithm. The result shows that the protocols that include the proposed algorithm have fewer path losses, lower overhead, shorter delay and higher data throughput compared with other protocols in VANET.
A Novel IEEE 802.11 Ad-Hoc MAC Scheme at Vehicle Emergency Situation
Sungdae Jung,Jaemyoung Kim,Sangsun Lee 한국자동차공학회 2006 한국자동차공학회 Symposium Vol.- No.-
This paper proposes a new scheme mode that can transmit emergency message efficiently by analyzing the DCF (Distributed Coordination Function) mode used in the vehicular Ad Hoc network of IEEE specification 802.11 and the PCF (Point Coordination Function) mode used the special case in emergency situations. The DCF and the PCF modes of IEEE 802.11 must coexist in a manner that permits both to operate concurrently within the same BSS (Basic Service Set). Although the BSS is basically used as the DCF mode in IEEE 802.11, the two access methods can be alternated in certain special cases in AP that support the PCF mode. Recent studies have proposed only a way to improve the fairness of message transmission using the contention-based DCF mode for vehicular Ad Hoc networks. However, it is more important to transmit data rapidly and reliably, rather than to improve the fairness in emergency situations. Through performance analysis, we propose the new scheme mode and confirmed that data can be transmitted quickly and correctly by utilizing the DCF mode and PCF mode in emergency situations.
상륙 태풍에 의한 마산만 폭풍해일 변동성 분석 - 1. 극치 모의 태풍 시나리오의 결정
Sungdae Han 한국재난정보학회 2015 한국재난정보학회 논문집 Vol.11 No.4
남해안에 상륙한 태풍 자료를 기초로 하여 분석한 결과, 태풍 이동방향의 분포는 Beta 확률밀도함수를 따르며, 태풍 눈에서의 기압저하는 Rayleigh 확률밀도함수를 따르는 것으로 판단되었다. 이를 바탕으로 6개 상륙 지점에 따라 가장 확률적으로 높은 태풍의 진로와 기압저하에 따른 태풍 매미급의 극치 태풍 모의 시나리오를 결정하였다. 모의된 태풍의 상륙지점에 따른 마산만에서의 폭풍해일 변동성이 후속 연구에서 수치 모의될 것이다. Based on the typhoon paths landed on the southern coast of Korea, the distribution of typhoon moving directions follow the Beta probability density function and that of pressure drops in typhoon eyes follow the Rayleigh probability density function. Consequently, the extreme typhoon simulation scenarios for six landing positions are determined as most probable one in moving direction and extreme one of Typhoon Maemi level in pressure drop. The variation of storm surges in Masan bay associated with simulated typhoon landing position is analyzed through the numerical experiments in the next paper as the second part.
Closed Loop-based extrinsic calibration of multi-modal sensors
Sungdae Sim,Kiho Kwak,Jun Kim,Sang Hyun Joo 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10
By increasing the requirement of reliable and accurate sensor information, the integration of multiple sensors has gained attention. Especially, the fusion of a LIDAR(Light Detection And Ranging) and a camera is one of the sensor combination broadly used because it provides the complementary and redundant information. Many existing calibration approaches consider the problem estimating the relative pose between each sensor pair such as a LIDAR and a camera. However, these approaches do not provide accurate solutions for multisensor configurations such as a LIDAR and cameras or LIDARs and cameras. In this paper, we propose a new extrinsic calibration algorithm using closed-loop constraints for multi-modal sensor configuration. The extrinsic calibration parameters are estimated by minimizing the distance between corresponding features projected onto the image plane. We conduct several experiments to evaluate the performance of our approach, such as comparison of the RMS distance of the ground truth and the projected points, and comparison between the independent sensor pair and our approach.
Sungdae Lim,Hyun Park,Ja Myoung Lee,Kwangho Lee,Won Heo,Soo Hyun Hwang 대한신경손상학회 2022 Korean Journal of Neurotrauma Vol.18 No.2
Objective: Tracheostomy is a necessary procedure for patients admitted to the neurosurgery intensive care unit (ICU) with severe brain injury, because mechanical ventilation must be maintained for a long time following neurologic failure. The purpose of this study was to compare conventional surgical tracheostomy (CST) and percutaneous dilatational tracheostomy (PDT) performed at the bedside in critically ill neurosurgery patients requiring tracheostomy to determine which procedure has comparative advantages. Methods: This retprospective study was conducted between January 2019 and December 2020. PDT was performed on 52 patients and CST was performed on 44 patients. The baseline characteristics, procedural characteristics, and clinical outcomes were recorded. Results: The mean operative time in the CST group was 25.5±6.5 minutes and that in the PDT group was 15.1±2.5 minutes; the difference was statistically significant (p<0.01). Four patients in the CST group and none in the PDT group experienced bleeding requiring transfusion. However, there was no significant difference in total ICU mortality or length of hospital stay. There were no statistical differences in the individual complication categories between the 2 study groups. Conclusion: There were fewer procedure-induced complications among patients receiving PDT than among those receiving CST. In addition, the treatment time for PDT was shorter than that for CST treatment.
Real-time AR Edutainment System Using Sensor Based Motion Recognition
Sungdae Hong,Hyunyi Jung,Sanghyun Seo 보안공학연구지원센터(IJSEIA) 2016 International Journal of Software Engineering and Vol.10 No.1
Recently the Natural User Interface (NUI) technology which is capable of appreciating the whole human body has come to the fore with the development of digital technology. And this new interface has settled as the competitive contents in the growing experiential learning contents market, by arousing participants’ interests and maximizing their learning effect, through a gesture recognition-based noncontact type interactive education. This study suggests various interpretations on the basis of the education contents production which enables participant to experience the human body in real time. Also it has developed a gesture interface by utilizing the Kinect sensor that can recognize a participant’s skeleton and behavior, and its education contents design has produced the end product by using Unity 3D authoring tool which can combine the real-time 3D model and animation together. Consequently, participant will be able to learn various inner organs such as brain and heart by different gestures, and the developed real-time human body exploring augmented reality system is expected to be widely used in many educational institutions
정성대(Sungdae Jung),조영선(Youngsun Cho),성유현(Yoohyun Sung),김형진(Hyungjin Kim),이명우(Myungwoo Lee),성봉진(Bongjin Seong) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11
Recently, two-wheeled vehicles are rapidly becoming electrified and electrified following four-wheeled vehicles. In the case of electric motorcycles, in order to increase the penetration rate, it is necessary to provide services related to electric motorcycles due to the characteristics of the market. In this paper, we introduce the services developed for electric motorcycles based on IoT, and the results of analyzing the data obtained from the pilot operation of the service.