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Adaptive Backstepping Control for Satellite Formation Flying
임형철,이상종,Hyochoong Bang 한국우주과학회 2006 Journal of Astronomy and Space Sciences Vol.23 No.4
Satellite formation ying has become a critical issue in the aerospace engineering be-cause it is consideredas an enablingtechnologyfor manyspace missions. Thus, manynonlinear control theories have been developed for the tracking problem of satelliteformation ying, which include full-nonlinear dynamics, external disturbances andparameter uncertainty. In this study, nonlinear adaptive control law is developed us-ing an adaptive backsteppingtechnique to solve the relative position tracking problemof the satellite formation ying in the presence of mass uncertainty and the boundedexternal disturbance. Simulation studies are included to demonstrate the proposedcontroller performance. The proposed controller is shown to guarantee the systemstability againsttheexternalboundeddisturbancesin thepresenceofmassuncertainty.
Study on the Optoelectronic Design for Korean Mobile Satellite Laser Ranging System
임형철,방승철,유성열,서윤경,박은서,김광동,나자경,장정균,장비호,박장현,박종욱 한국우주과학회 2011 Journal of Astronomy and Space Sciences Vol.28 No.2
Korea Astronomy and Space Science Institute has been developing one mobile and one stationary satellite laser ranging system for the space geodesy research and precise orbit determination since 2008, which are called as ARGO-M and ARGO-F, respectively. They will be capable of daytime laser ranging as well as nighttime and provide the accurate range measurements with millimeter level precision. Laser ranging accuracy is mostly dependent on the optics and optoelectronic system which consists of event timer, optoelectronic controller and photon detectors in the case of ARGO-M. In this study, the optoelectronic system of ARGO-M is addressed and its critical design is also presented. Additionally, the experiment of the integrated optoelectronic system was performed in the laboratory to validate the functional operation of each component and its results are analyzed to investigate ARGO-M performance in advance.
KNN 알고리즘을 활용한 초음파 센서 간 간섭 제거 기법
임형철,이성수 한국전기전자학회 2022 전기전자학회논문지 Vol.26 No.2
This paper introduces an interference elimination method using k-nearest neighbor (KNN) algorithm for precisedistance estimation by reducing interference between ultrasonic sensors. Conventional methods compare currentdistance measurement result with previous distance measurement results. If the difference exceeds somethresholds, conventional methods recognize them as interference and exclude them, but they often suffer fromimprecise distance prediction. KNN algorithm classifies input values measured by multiple ultrasonic sensors andpredicts high accuracy outputs. Experiments of distance measurements are conducted where interferencefrequently occurs by multiple ultrasound sensors of same type, and the results show that KNN algorithmsignificantly reduce distance prediction errors. Also the results show that the prediction performance of KNNalgorithm is superior to conventional voting methods.
공격 횟수와 공격 유형을 고려하여 탐지 성능을 개선한차량 내 네트워크의 침입 탐지 시스템
임형철,이동현,이성수 한국전기전자학회 2022 전기전자학회논문지 Vol.26 No.4
This paper proposes an intrusion detection system for in-vehicle network to improve detection performanceconsidering attack counts and attack types. In intrusion detection system, both FNR (False Negative Rate), whereintrusion frame is misjudged as normal frame, and FPR (False Positive Rate), where normal frame is misjudged asintrusion frame, seriously affect vechicle safety. This paper proposes a novel intrusion detection algorithm toimprove both FNR and FPR, where data frame previously detected as intrusion above certain attack counts isautomatically detected as intrusion and the automatic intrusion detection method is adaptively applied accordingto attack types. From the simulation results, the propsoed method effectively improve both FNR and FPR in DoS(Denial of Service) attack and spoofing attack.
지능형건물의 생애주기 서비스 지원을 위한 체계개발 및 적용우선순위 도출
임형철 대한건축학회지회연합회 2011 대한건축학회연합논문집 Vol.13 No.3
본 연구의 결과물인 지능형홈의 생애주기관리를 위한 서비스아키텍쳐를 정의하였으며, 각 서비스 별로 업무/데이터/하드웨어/소프트웨어에 대한 고유속성을 정의할수 있으며, 각 서비스에 대하여 기능정의를 통한 프로세스와 주요입출력정보, 담당조직 등을 정의하여 생애주기동안 활용되고 갱신될 수 있는 체계를 구축하였다. 단, 시기적으로 모든 지능형홈 서비스가 적용가능하지 않고, 거주자별로 원하는 서비스의 유형이 상이하므로, 본 연구에서는 적용 우선순위 도출을 위하여 크게 기술지원도와 수요자 선호도를 조사하여 그 우선순위를 도출하였다. 우선순위를 토대로 기술개발 및 서비스적용의 시급성과 적용가능성을 파악할 수 있으며, 서비스아키텍쳐의 활용을 통하여, 프로세스를 포함한 정보자원 기술서를 전산화가능하며, 특히 업무수행을 위하여 다양하게 활용되는 어플리케이션과 소프트웨어와 프로세스와 연계성을 확보함으로써, 특성 업무처리개시 단계의 투입물과 처리완료 단계의 산출물을 명확히 인식하고 최신버전의 데이터를 관리할 수 있는 체계로서 활용가능하다. The main purpose of this research is user oriented system for smart home service with relatively short LifeCycle period as architectural component, connecting process model and data regarding smart home technical components. Smarthome Service Architecture for framework of Lifecycle management is consist of three procedure, that is, Service Breakdown Structure and Service Process model, Documentation of service process model with access data and organizations, Construction of Architecture with Service Process model and Breakdown Structure. This research consists with investigation of company and use/management of lifecycle, is used for draft informations of architecture for smarthome service. Then, it is phase of service architecture, that is divided service framework and process modeling work, as these work completed, we will establish management method of datawarehouse and detail database of service. (architectural and non-architectural data)
Baseline Design and Performance Analysis of Laser Altimeter for Korean Lunar Orbiter
임형철,Gregory A. Neumann,최명환,유성열,방승철,가능현,박종욱,최만수,박은서 한국우주과학회 2016 Journal of Astronomy and Space Sciences Vol.33 No.3
Korea’s lunar exploration project includes the launching of an orbiter, a lander (including a rover), and an experimental orbiter (referred to as a lunar pathfinder). Laser altimeters have played an important scientific role in lunar, planetary, and asteroid exploration missions since their first use in 1971 onboard the Apollo 15 mission to the Moon. In this study, a laser altimeter was proposed as a scientific instrument for the Korean lunar orbiter, which will be launched by 2020, to study the global topography of the surface of the Moon and its gravitational field and to support other payloads such as a terrain mapping camera or spectral imager. This study presents the baseline design and performance model for the proposed laser altimeter. Additionally, the study discusses the expected performance based on numerical simulation results. The simulation results indicate that the design of system parameters satisfies performance Korea’s lunar exploration project includes the launching of an orbiter, a lander (including a rover), and an experimental orbiter (referred to as a lunar pathfinder). Laser altimeters have played an important scientific role in lunar, planetary, and asteroid exploration missions since their first use in 1971 onboard the Apollo 15 mission to the Moon. In this study, a laser altimeter was proposed as a scientific instrument for the Korean lunar orbiter, which will be launched by 2020, to study the global topography of the surface of the Moon and its gravitational field and to support other payloads such as a terrain mapping camera or spectral imager. This study presents the baseline design and performance model for the proposed laser altimeter. Additionally, the study discusses the expected performance based on numerical simulation results. The simulation results indicate that the design of system parameters satisfies performance requirements with respect to detection probability and range error even under unfavorable conditions.