• Title/Summary/Keyword: LINS

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Fault Detection Method of Laser Inertial Navigation System Based on the Overlapping Model (중첩모델 기반 레이저 관성항법장치 고장검출 기법)

  • Kim, Cheon-Joong;Yoo, Ki-Jeong;Kim, Hyeon-Suk;Lyou, Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.11
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    • pp.1106-1116
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    • 2011
  • LINS (Laser Inertial Navigation System) consists of RLG (Ring Laser Gyroscopes)/accelerometers and provides real-time navigation information to the target system. Therefore it is very important to make a decision in the real time whether LINS is in the normal operation or not. That is called a fault detection method. In this paper, we propose the fault detection method of LINS based on the overlapping model. We also show that the fault detection probability is increased through overlapping the hardware model and the software model. It is verified through the long-term operation and RAM (Reliability Availability Maintainability) analysis of LINS that the fault detection method proposed in this paper is able to detect about 97% of probable system failures.

Performance Analysis on the Initial Alignment of Laser Inertial Navigation System (레이저 관성항법장치 초기정렬 성능 분석)

  • Kim, Hyun-Seok;Kim, Cheon-Joong;Lee, Tae-Gyoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.5
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    • pp.622-635
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    • 2009
  • Laser Inertial Navigation System(LINS) consists of Ring Laser Gyroscopes(RLG) and accelerometers. RLG has a lock-in region in which there is zero output for input angular rates less than about 0.1deg/sec. The lock-in region is generated by the imperfect mirrors in RLG. To avoid the lock-in region, a sinusoidal motion called dither motion is applied on RLG. Therefore this dither motion is measured by RLG/accelerometer even if at a stop state. In this situation, the performance on the initial alignment of LINS can be degraded. In this paper, we analyze the performance on the initial alignment of LINS theoretically and experimentally. Analysis results include how dither motion, the pre-filter and the corner frequency in alignment loop affects the performance on the initial alignment of LINS.

Fault Detection Method of Laser Inertial Navigation System Using FFT (FFT를 이용한 레이저 관성항법장치 고장검출 기법)

  • Yoo, Hae-Seong;Kim, Cheon-Joong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.5
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    • pp.502-510
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    • 2009
  • Laser Inertial Navigation System(LINS) consists of Ring Laser Gyroscopes(RLG) and accelerometers. RLG has a lock-in region in which there is zero output for input angular rates less than 0.1deg/sec. The lock-in region is generated by the imperfect mirrors in RLG. To avoid the lock-in region, sinusoidal motion which is called dither motion is applied on RLG. Therefore without the fault in LINS, the dither motion must be measured by RLG/accelerometer. In this paper, we propose the method to detect the fault of LINS through checking out whether or not the dither motion is always measured by RLG/accelerometer using the Fast Fourier Transformation(FFT) on the real time. The feasibility of the fault detection method proposed in this paper is verified through the stationary and van test.

Performance Analysis in Disturbance on Initial Alignment of Laser Inertial Navigation System Using Unscented Kalman Filter (UKF를 적용한 레이저 관성항법장치의 외란에 대한 초기정렬 성능분석)

  • Oh, Juhyun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.4
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    • pp.537-543
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    • 2014
  • RLG(Ring Laser Gyroscope) is a main device of LINS(Laser Inertial Navigation System). RLG has the lock-in region in which there is no output signal. To alleviate the lock-in problem, a mechanical oscillation, the dither motion, is applied on RLG. A LPF(Low Pass Filter) is usually used on the output of RLG and accelerometer to remove the noise that is made by the dither motion. When the LINS is induced the disturbance during the initial alignment, it takes more time on alignment due to the use of the LPF and a fixed gain controller. In this paper, an initial alignment using UKF(Unscented Kalman Filter) is designed and analysed. Analysis include comparison between conventional initial alignment loop using fixed gain type controller and proposed initial alignment using UKF. Moreover, Disturbance inducing test results are demonstrated.

Combination of Anterior and Posterior Subcutaneous Internal Fixation for Unstable Pelvic Ring Injuries: The "Hula Hoop Technique"

  • Balbachevsky, Daniel;Pires, Robinson Esteves;Sabongi, Rodrigo Guerra;Lins, Theophilo Asfora;Carvalho, Geiser de Souza;Fernandes, Helio Jorge Alvachian;Reis, Fernando Baldy dos
    • Journal of Trauma and Injury
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    • v.32 no.1
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    • pp.51-59
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    • 2019
  • Unstable pelvic ring lesions are usually treated with internal fixation. In patients presenting clinical instability or soft tissue complication risk, external fixation is a safe treatment option. However, pin tract infection, insufficient biomechanical properties, difficulty sitting and changing decubitus are important drawbacks related to the treatment. The present study reports the association of anterior and posterior subcutaneous internal fixation by applying spine-designed implants on the pelvic ring disruption: supra-acetabular pedicle screws with an interconnecting rod (Infix), plus posterior transiliac fixation with the same system, which the authors have named the "Hula Hoop Technique".

The Effect of Ascorbic Acid on the Changes in Amounts of Pyridinoline form Bone Collagen during In vitro Aging (In vitro Aging에 있어서 콜라겐 성숙가교의 변화에 대한 비타민 C의 영향)

  • 김미향
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.3
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    • pp.501-506
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    • 1997
  • As pyridinoline is one of the predominant cross-lins in a mature collagen, pyridinoline formation may be an essential step during the growth process to obtain normal mechanical strength in collagen fibrils. However, the excess formation of pyridinoline in collagen will probably make the tissue stiffer, less soluble and less digestible by enzymes. We investigated the changes of pyridinoline of bone collagen and the role of ascforbic acid(AsA) on the formation of pyridinoline. The pyridinoline content of bone collagen significantly increased during incubation for 1~5 weeks at 37$^{\circ}C$ in vitro. The addition of AsA decreased pyridinoline to half the amount found in controls with 5 week incubation. When dehydroascorbic acid(DHA) and L-2, 3-diketogulonic acid (DKG), the oxidative products of AsA, were supplemented to bone collagen solution instead of AsA, the content of pyridinoline in bone collagen was about 80% or 70% that of controls, respectively. These results suggest that pyridinoline content decreases by the addition of AsA in vitro. Furthermore, it was shown that AsA in oxidized from also affected the formation of pyridinoline.

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Electrical and Optical Characteristics of Inductively Coupled Plasma by Ar Gas Pressure and Rf Power (Ar 가스 압력과 RF 전력에 따른 유도결합형 플라즈마의 전기적 및 광학적 특성)

  • 최용성;허인성;이영환;박대희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.5
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    • pp.560-566
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    • 2004
  • In this paper, the electrical and emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma (ICP) with the variation of argon gas pressure and RF power. The RF output was applied to the antenna in the range of 5∼50 W at 13.56 MHz. The internal plasma voltage of the chamber and the probe current were measured while varying the supply voltage to the Langmuir probe in the range of -100V∼+100V. When the pressure of argon gas was increased, electric current was decreased. There was a significant electric current increase from 10 to 30 W. Also, when the RF power was increased, electron density was increased. Also, the emission spectrum, Ar- I lins, luminance were investigated. At this time, the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10∼60 mTorr, 10∼300 W, respectively. This implies that this method can be used to find an optimal RF power for efficient light illumination in an electrodeless fluorescent lamp.

FE analysis of RC pipes under three-edge-bearing test: Pocket and diameter influence

  • Kataoka, Marcela Novischi;da Silva, Jefferson Lins;de Oliveira, Luciane Marcela Filizola;El Debs, Mounir Khalil
    • Computers and Concrete
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    • v.20 no.4
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    • pp.483-490
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    • 2017
  • This paper studies on the behavior of reinforced concrete (RC) pipes used in basic sanitation in the conduction of storm water and sanitary sewer. Pipes with 800 mm and 1200 mm in diameter were analyzed. The 800 mm pipes were built with simple reinforcement and the 1200 mm pipes with double reinforcement. For the two diameters of pipes the presence or absence of the pocket was evaluated, and the denomination of each one is spigot and pocket pipe (SPP) and ogee joint pipe (OJP), respectively. The 3D numerical models reproduce the three-edge-bearing test that provides information about the strength and stiffness of the reinforced concrete pipes. The validation of the computational models was carried out comparing the vertical and horizontal displacements on the springline and crown/invert and it was also evaluated the reinforcement strains and the crack pattern. As a main conclusion, the numerical models represented satisfactorily the behavior of the pipes and can be used in future studies in parametric analysis.

In vivo optical coherence tomographic imaging to monitor gingival recovery and the adhesive interface in aesthetic oral rehabilitation: A case report

  • Graca, Nathalia Del Rio Lyra;Palmeira, Anna Rebeca de Barros Lins Silva;Fernandes, Luana Osorio;da Silva Pedrosa, Marlus;Guimaraes, Renata Pedrosa;Santos, Saulo Cabral dos;Gomes, Anderson Stevens Leonidas;da Silva, Claudio Heliomar Vicente
    • Imaging Science in Dentistry
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    • v.49 no.2
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    • pp.171-176
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    • 2019
  • The available methods for veneer evaluation are limited to clinical and radiographic examinations, which may not allow the appropriate identification of failure. In this report, we demonstrate the use of optical coherence tomography (OCT) as a noninvasive diagnostic and follow-up method to evaluate gingival recovery and the adhesive interface in aesthetic oral rehabilitation involving periodontal plastic surgery and ceramic laminate veneers. OCT was efficient for evaluating both soft and hard tissues, as well as the quality of the adhesive interface. In conclusion, OCT was found to be a promising approach for the professional evaluation of aesthetic oral rehabilitation, as it was capable of generating images that enabled the analysis of gingival recovery and the adhesive interface.

Self-Alignment/Navigation Performance Analysis in the Accelerometer Resonance State Generated by Dither Motion of Ring Laser Gyroscope in Laser Inertial Navigation System (레이저 관성항법장치에서 링레이저 자이로 디더 운동에 의한 가속도계 공진이 자체 정렬/항법 성능에 미치는 영향 분석)

  • Kim, Cheonjoong;Lim, Kyungah;Kim, Seonah
    • Journal of the Korea Institute of Military Science and Technology
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    • v.24 no.6
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    • pp.577-590
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    • 2021
  • In this paper, we theoretically analyzed the self-alignment/navigation performance in the accelerometer resonance state generated by dither motion of ring laser gyroscope in LINS and verified it through simulation. As a result of analysis, it is confirmed that the amplitude of the accelerometer measurement amplified in the accelerometer resonance state is decreased in the process of sampling per the navigation calculation period and that frequency is changed by the aliasing effect too. It was also analysed that the attitude error in self-alignment is determined by the amplitude/frequency of the accelerometer measurement, the gain of the self-alignment loop, and the velocity and position error in the navigation is determined by the amplitude/frequency/phase error of the accelerometer measurement. This analysis and simulation results show that the self-alignment and navigation performance is not be degraded only when the amplification factor of the accelerometer measurement in the accelerometer resonance state is 3 or less