• Title/Summary/Keyword: Precision Approach

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Vision Processing for Precision Autonomous Landing Approach of an Unmanned Helicopter (무인헬기의 정밀 자동착륙 접근을 위한 영상정보 처리)

  • Kim, Deok-Ryeol;Kim, Do-Myoung;Suk, Jin-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.1
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    • pp.54-60
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    • 2009
  • In this paper, a precision landing approach is implemented based on real-time image processing. A full-scale landmark for automatic landing is used. canny edge detection method is applied to identify the outside quadrilateral while circular hough transform is used for the recognition of inside circle. Position information on the ground landmark is uplinked to the unmanned helicopter via ground control computer in real time so that the unmanned helicopter control the air vehicle for accurate landing approach. Ground test and a couple of flight tests for autonomous landing approach show that the image processing and automatic landing operation system have good performance for the landing approach phase at the altitude of $20m{\sim}1m$ above ground level.

Evolutionary computation approach for automated synthesis design of mechanical structures (기계 구조의 합성적 자동생성을 위한 진화연산)

  • 이인호;차주헌;김재정
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.643-646
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    • 2002
  • This paper proposes an evolutionary computation approach for automated design of mechanical structures especially in its early stage of design phases. Due to the known characteristics of the stage, the approach basically involves a synthetic design method with the composition of building blocks representing the elements of mechanical objects. In order for the building blocks to be more suitable for representation and evolution of mechanical structures, Elementary Cell Blocks (ECBs) are introduced as new building blocks. A new Darwinian evolution process for the new building blocks is also necessarily involved in the approach. We have demonstrated the implementation of the approach with the design of multi-step gear systems.

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A Study on an Application of the Protection for the Visual Segment of the Approach Procedure focused on Taean Airport (접근절차의 시계구간 보호 적용 연구 - 태안비행장을 중심으로 -)

  • Kim, Dohyun;Hong, Seung Beom
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.22 no.2
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    • pp.9-15
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    • 2014
  • 'Visual segment surface' means a surface that extends from the missed approach point of non precision approaches (or the decision altitude location for approaches with vertical guidance and precision approaches) to the threshold to facilitate the identification of and protection from obstacles in this visual segment of the approach. Validation is the necessary final quality assurance step in the procedure design process, prior to publication. The purpose of validation is the verification of all obstacle and navigation data, and assessment of flyability of the procedure. This paper shows how to apply the protection for the visual segment of the approach procedure, and the results of the validation for visual segment surface conducted at an airport.

Interference-Free Tool Approach Directions in Multi-Axis NC Machining of Sculptured Surfaces (자유 곡면의 다축 NC 가공시 간섭 없는 공구 접근 자세 영역)

  • J.G. Kang
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.7
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    • pp.108-115
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    • 1997
  • In this paper, an algorithm of computing interference-free tool approach directions(visibility cone) with consideration of tool volume at an arbitrary point of a sculptured surface is developed. The surface is first approximated into a polyhedron with smaller subpatches and the tool approach directions are evenly sampled so as to test accessibility. Then the visibility cone is computed by testing if each approach direction is interfered by other surface subpatches. The results are represented as the binary spherical map which transform geometric information on sphere into aogebraic one. The developed algorithm is implemented and tested by several sculptured surfaces, convincing it can be easily used as a tool for not only interference- free tool approach directions but also determining process planning of multi-axis NC machining of sculp- tured surfaces

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Axiomatic Approach for desing Appraisement and Development DVD (II) (DVD 설계평가 및 개선을 위한 공리적 접근 (II))

  • Moon, Yong-Rak;Cha, Sung-Woon;Heo, Bo-Seog
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.9
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    • pp.82-88
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    • 1999
  • In order to execute the major role as the high density large capacity data storage device, which is one of the major characteristics of DVD(Digital Versatile Disk), there must be a method to effectively absorb the external impact or internal vibration. The DVD which has been developed until now tries to control two different types of vibrations, using only one absorber. But this goes against the independence Axiom of Axiomatic Approach which makes the design to be coupled. And in fat most of the malfunctions occurring during DVD data input/output is due to impact or vibration. Therefore in this paper, the vibration absorption system and operation reliability of DVD will be evaluated with the Axiomatic Approach and plans and feasibility to design an improved vibration absorption system will be provided also based on the Axiomatic Approach.

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Feasibility Study on Domestic Development of a Precision-Landing System for Korean Military Based on GNSS (위성항법시스템 기반 한국형 군용 정밀착륙체계 국내개발 방향 및 기술타당성 분석)

  • Lee, Keehoon;Ahn, Jongsun;Lee, Young Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.6
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    • pp.762-770
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    • 2013
  • Korean military is currently using and operating a precision approach and landing system, called RAPCON (ASR/PAR), which is imported from overseas. However, drawbacks of this system are operational and cost problems that come along, e.g. straightness of the radio waves, limited ability of narrow searching, lack of interoperability, and high cost of installation and maintenance. Moreover, as the civilian air traffic control uses a similar system compared to the military, the so called DME/VOR/ILS, disturbance between these two systems triggered the consideration of GNSS as alternative system. In this paper, we conduct a research on trends in the field of precise approach and landing systems based on GNSS, analyze weaknesses of GNSS(jamming, fault) and consider possible solutions. Furthermore, we propose the precise approach and landing system based on GNSS to be used by the Korean military as we found it to be also suitable for military purposes. Finally, we examine the benefits of a domestic development with different focuses(development/cost of mass production/operational advantages and potential for increased performance).

An Effective Anomaly Detection Approach based on Hybrid Unsupervised Learning Technologies in NIDS

  • Kangseok Kim
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.18 no.2
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    • pp.494-510
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    • 2024
  • Internet users are exposed to sophisticated cyberattacks that intrusion detection systems have difficulty detecting. Therefore, research is increasing on intrusion detection methods that use artificial intelligence technology for detecting novel cyberattacks. Unsupervised learning-based methods are being researched that learn only from normal data and detect abnormal behaviors by finding patterns. This study developed an anomaly-detection method based on unsupervised machines and deep learning for a network intrusion detection system (NIDS). We present a hybrid anomaly detection approach based on unsupervised learning techniques using the autoencoder (AE), Isolation Forest (IF), and Local Outlier Factor (LOF) algorithms. An oversampling approach that increased the detection rate was also examined. A hybrid approach that combined deep learning algorithms and traditional machine learning algorithms was highly effective in setting the thresholds for anomalies without subjective human judgment. It achieved precision and recall rates respectively of 88.2% and 92.8% when combining two AEs, IF, and LOF while using an oversampling approach to learn more unknown normal data improved the detection accuracy. This approach achieved precision and recall rates respectively of 88.2% and 94.6%, further improving the detection accuracy compared with the hybrid method. Therefore, in NIDS the proposed approach provides high reliability for detecting cyberattacks.