• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2001.05a
• /
• pp.104-104
• /
• 2001

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2004.05a
• /
• pp.140-140
• /
• 2004

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.4
• /
• pp.394-402
• /
• 1999

In this paper, we present an effective RLS algorithm with forgetting factor of Erlang function for the system identification. In the proposed algorithm, the forgetting factor decreases monotonically in the first stage, and then it increases monotonically in the second stage in contrary to the conventional forgetting factor RLS algorithms. In addition, annealing effect and an asymptotically stability of the proposed algorithm is discussed based on the analysis of convergency property on. Simulation results for the system identification problem indicate the superiority of the proposed algorithm in comparison to the RLS algorithm such as NLMS and Kalman filter based algorithm.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1701-1705
• /
• 2004

This paper presents a design and analysis of electromechanical sigma-delta modulator for MEMS gyroscope, which enables us to control the proof mass and to obtain an exact digital output without additional A/D conversion. The system structure and the circuit realization of the sigma-delta modulation are simpler than those of the analog sensing and feedback circuit. Based on the electrical sigma-delta modulator theory, a compensator is designed to improve the closed loop resolution of the sensor. With the designed compensator, we could obtain enhanced closed-loop performances of the gyroscope such as larger bandwidth, lower noise, and digital output comparing with the results of analog open-loop system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1537-1541
• /
• 2003

In this paper, presented is a feedback control performance of vibratory gyroscope at various vacuum levels. Micro gyroscope, whose operation is based on the vibrating motion at the vacuum conditions, is highly influenced by the vacuum level of the operating circumstances. In general, we apply the feedback control scheme to the gyroscope in order to improve the performances of the sensor. And control performances of the gyroscope are related to those vacuum levels. So we need investigate the performances of the closed loop control at various vacuum conditions comparing with those of the open loop. The experimental results show that the sensitivity of the closed loop is less than that of the open loop especially in low vacuum conditions. Therefore, there should be trade-off between sensitivity and other sensor performances such as linearity, bandwidth when we apply feedback control to the gyroscope.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.574-578
• /
• 2004

In this paper, a nonlinear feedback system is analyzed for a surface micromachined resonant accelerometer. For this, a brief illustration of the plant dynamics is given. In the analysis, the periodic signal in the nonlinear feedback loop is obtained by the limit cycle point, which is best approximated via the describing function method. Considering the characteristic feature of plant dynamics, a simple phase shifted relay with finite slope is designed for the nonlinearity implementation. With a describing function for random plus sinusoidal input, we analyzed the effect of a white Gaussian noise on oscillation frequency. Finally, simulation and experimental result is given.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.592-595
• /
• 2004

This paper presents a study on the development of a multi-sensing inertial sensor with a single mechanical structure, which can be used both as a gyroscope and an accelerometer. The proposed MEMS gyro-accelerometer is designed to detect the angular rate and the acceleration at the same time using two separate detection circuits for one proof mass. In this study, the detection and signal processing circuit for an effective signal processing of different inertial measurements is designed, fabricated, and tested. The experimental results show that the performances of the gyro-accelerometer have resolutions of 1mg and 0.025deg/sec and nonlinearities of less than 0.5% for the accelerometer and the gyroscope, respectively, which are similar results with those of sensors with different structures and different detection circuits. The size of the sensor is reduced almost by 50% comparing with the sensors of separated proof mass.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2632-2635
• /
• 2003

This paper designs a software signal generator for the new GPS L2 civil signal. The CM/CL code and the message structure of L2CS described in GPS ICD PPIRN-200C-007 are used in designing the signal generator. The output of the GPS signal generator is designed as the sampled IF data with the sampling frequency 5.7MHz and stored in the binary data format. By analyzing both the spectrum characteristics of the output signal and the correlation properties of the CM/CL code, the validation of the designed GPS signal generator is shown. It should be mentioned that the modeling of the GPS satellite constellation and the error sources remains for implementing the software space segment of GPS.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1822-1825
• /
• 2003

A practical range estimator based on the robust Kalman filter is proposed to solve the range estimation problem for surface to air missile(SAM) homing guidance. Apart from the previous works based on the extended Kalman filter(EKF) with bearing only measurement, the proposed scheme makes use of line-of-sight(LOS) rate to ensure the fast convergency at long-range. In this reason, the robust Kalman filter is considered to deal with LOS rate measurement error. The recursive linear structure of proposed filter is easy to implement and make it possible to reduce computational burdens. Moreover, it shows good estimation performance without specific guidance law such as oscillation proportional navigation guidance(OPNG).

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.33 no.5
• /
• pp.430-434
• /
• 2011

Extraskeletal osteochondroma is an uncommon benign tumor that arises in soft tissues lacking continuity with an adjacent bone and joint. Due to similar histopathological findings, extraskeletal osteochondroma is often misdiagnosed for a conventional osteochondroma, the most common benign tumor that arises from the epiphyseal plates of long bones. The pathogenesis of extraskeletal osteochondroma is unclear, but metaplasia of synovial mesenchymal tissue is the best supported etiology. The most common sites of extraskeletal osteochondroma are the hands and feet, and it is rarely found in the maxillofacial area. We present a case of a two-year-old boy with a giant extraskeletal osteochondroma that developed in the masticatory space of the mandible along with a review of the relevant literature.