• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.738-745
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• 2001

In this paper, when the moving object move to the three-dimentional space, the tracking system track the moving object using the fuzzy reasoning. The joint angle el of the manipulator rotate from $0^{\circ}\; to\; 360^{\circ}$ , and the joint angle $\theta_2$rotate from$0^{\circ}\; to\; 360^{\circ}$. The fuzzy singleton is used for fuzzification and the control rule is twenty five and the fuzzy inference method is simplified Mamdani's reasoning and the defuzzification is the SCOG(Simplified Center Of Gravity) of the fuzzy controller To measure of the performance of the designed system, the fuzzy controller is compared with the CTM(Computed Torque Method) controller at the same condition. when the disturbance torque is ON, the both of CTM and fuzzy controller tracked object without error, However, the disturbance torque changed 0.4N, the CTM controller is 10 times greater than fuzzy controller at the sum of absolute error difference. The designed system is showed it's robustness against with disturbance.

• Journal of Korean Society for Quality Management
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• v.49 no.3
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• pp.245-254
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• 2021

Purpose: In order to accurately reach an underwater projectile to a target point, reliable INS and accurate arrangement of INS between master and slave INS is paramount. Unlike terrestrial and aerial environments, underwater projectile will operates in a restricted environment where location information cannot be received or sent through satellites. In this report, we review the factors affecting the transfer alignment of master and slave INS, as well as how to improve the positional error between INS through improved transfer alignment algorithms. Methods: In this work, we propose an improvement algorithm and verify it through simulation and driving test. The simulation confirmed the difference in the transfer alignment azimuth by fitting the MINS and SINS indoors, displacement in posture, and the process of transfer alignment between MINS and SINS through a driving test to confirm algorithm can improve the arrangement. Results: According to this study, reason for the error in the transfer alignment between MINS/SINS is the factors of the system where movements such as roll, pitch, yaw are not inter locked in real time due to the delay in transmit/receive system. And confirm that the improved algorithm has a desirable effect on accuracy. Conclusion: Through this work, it is possible to identify ways to improve the accuracy of underwater projectiles to reach their target points under various underwater environments and launch condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.187-194
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• 2019

The off-axis Infra-Red(IR) seeker is mounted on the nose cone side of the anti-air high speed missile to alleviate thermal shield effect due to aerodynamic heating. The seeker output can not be regarded as the Line-of-Sight(LOS) rate any more as missile's roll motion to keep the target tracking is associated. In this paper, we propose a method to calculate the LOS rate for off-axis seeker on a 2-axis gimbal. Firstly, true LOS rate equations are analytically derived but not implementable because boresight error rate is not measurable. And then the first order lag approximation to obtain boresight error rate is proposed. The proposed LOS rate calculation method can compensate the coupling effect by considering the rotations of missile and gimbal. The performance of the proposed method is verified via full nonlinear 6-DOF(Degree of Freedom) simulations.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.1
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• pp.177-186
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• 2017

Recently, Autonomous vehicles are getting hot attention. Amazon, the biggest online shopping service provider is developing a delivery system that uses drones. This kinds of platforms are need accurate attitude information for navigation. In this paper, a structure design of AHRS using low-cost inertia sensor is proposed. To estimate attitudes a Kalman filter which uses a quaternion based dynamic model, bias-removed measurements from MEMS Gyro, raw measurements from MEMS accelerometer and magnetometer, is designed. To remove bias from MEMS Gyro, an additional Kalman filter which uses raw Gyro measurements and attitude estimates, is designed. The performance of implemented AHRS is compared with high price off-the-shelf 3DM-GX3-25 AHRS from Microstrain. The Gyro bias was estimated within 0.0001[deg/s]. And from the estimated attitude, roll and pitch angle error is smaller than 0.2 and 0.3 degree. Yaw angle error is smaller than 6 degree.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.345-354
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• 2014

Purpose : We evaluated the usefulness of $Fraxion^{(R)}$ system and s-thermoplastic mask by analyzing setup error when stereotactic radiousurgery (SRS) was treated for brain metastasis. Materials and Methods : 6 patients who received definite diagnosis as brain metastasis between May 2014 and October 2014 were selected. 3 patients were immobilized s-thermoplastic mask and mouthpiece (group1), while $Fraxion^{(R)}$ system was used for the other 3 patients (group2). Cone Beam Computerized Tomography (CBCT) scan was acquired to register planning CT scan. The registration offset was compared for each group. We compared and reported the errors using maximum, minimum, mean, and standard deviation of registration offsets. Furthermore, We used the same method as patient specific quality assurance to verify absorbed dose of PTV. Results : The setup error which is registration offset was reduced 83% in x, 40% in y, and 92% in z-direction when $Fraxion^{(R)}$ system was used compared to the case of using s-thermoplastic mask and mouthpiece. In addition, using $Fraxion^{(R)}$ system showed improved results in rotational components, pitch (rotation along x-axis), roll (y), and yaw (z) which were reduced 64, 88, and 87% respectively compared to the case of using s-thermoplastic mask and mouthpiece. In dosimetry results, when s-thermoplastic mask and mouthpiece used, absorbed dose was reduce 83% compared to before and after registration. However, using $Fraxion^{(R)}$ system showed only 1.9%. All percentage were calculated with respect to average value. Conclusion : Using $Fraxion^{(R)}$ system including mouthpiece, Fraxion frame, frontpiece, and thermoplastic mask, showed better repeatability and precision compared to using s-thermoplastic mask and mouthpiece, which is consequently considered as more improved immobilization system.

• International Journal of Reliability and Applications
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• v.2 no.3
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• pp.209-240
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• 2001

Computer-based simulation and analysis is used extensively in engineering for a variety of tasks. Despite the steady and continuing growth of computing power and speed, the computational cost of complex high-fidelity engineering analyses and simulations limit their use in important areas like design optimization and reliability analysis. Statistical approximation techniques such as design of experiments and response surface methodology are becoming widely used in engineering to minimize the computational expense of running such computer analyses and circumvent many of these limitations. In this paper, we compare and contrast five experimental design types and four approximation model types in terms of their capability to generate accurate approximations for two engineering applications with typical engineering behaviors and a wide range of nonlinearity. The first example involves the analysis of a two-member frame that has three input variables and three responses of interest. The second example simulates the roll-over potential of a semi-tractor-trailer for different combinations of input variables and braking and steering levels. Detailed error analysis reveals that uniform designs provide good sampling for generating accurate approximations using different sample sizes while kriging models provide accurate approximations that are robust for use with a variety of experimental designs and sample sizes.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.186-193
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• 2002

A new integrated torque and speed control algorithm has been proposed for the load balancing of rollers in continuous strip processing line(CSPL). Using the proposed method, the output torque and speed can be controlled to follow the reference in spite of nonideal effects such as the speed reference error and/or the controller gain difference between rolls. This new algorithm can be easily implemented in a motor drive system of each roll as it does not require the torque feedback of the others. Through the simulation and experiments for a simple CSPL consists of four driven rolls, the load balancing performance of the proposed scheme is presented and compared with that of conventional method.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.169-176
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• 2000

Longitudinal and lateral forces acting on tires are known to be closely related to the tract-ability braking characteristics handling stability and maneuverability of ground vehicles. In thie paper in order to develop tire force monitoring systems a monitoring model is proposed utilizing not only the vehicle dynamics but also the roll motion. Based on the monitoring model three monitoring systems are developed to estimate the tire force acting on each tire. Two monitoring systems are designed utilizing the conventional estimation techniques such as SMO(Sliding Mode Observer) and EKF(Extended Kalman Filter). An additional monitoring system is designed based on a new SKFMEC(Scaled Kalman Filter with Model Error Compensator) technique which is developed to improve the performance of EKF method. Tire force estimation performance of the three monitoring systems is compared in the Matlab simulations where true tire force data is generated from a 14 DOF vehicle model with the combined-slip Magic Formula tire model. The built in our Lab. simulation results show that the SKFMEC method gives the best performance when the driving and road conditions are perturbed.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.195-202
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• 2004

This paper presents the fabrication and evaluation of mechanical behavior for a peristaltic micropump by flow simulation. The valve-less micropump using the diffuser/nozzle is consists of the lower plate, the middle plate, the upper plate and the tube that connects inlet and outlet of the pump. The lower plate includes the channel and the chamber, and the plain middle plate are made of glass and actuated by the piezoelectric translator. Channels and a chamber on the lower plate are fabricated on high processability silicon wafer by the DRIE(Deep Reactive Ion Etching) process. The upper plate does the roll of a pump cover and has inlet/outlet/electric holes. Three plates are laminated by the aligner and bonded by the anodic bonding process. Flow simulation is performed using error-reduced finite volume method (FVM). As results of the flow simulation and experiments, the single chamber pump has severe flow problems, such as a backflow and large fluctuation of a flow rate. It is proved that the double-chamber micropump proposed in this paper can reduce the drawback of the single-chamber one.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.309-317
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• 2010

This paper proposes an efficient measurement system for the velocity and direction of the wind using the dual rotor wind power generator in vessel. Conventional digital measurement system recognizes the direction and the velocity of the wind using the electric compass or synchronous motor and Vane probe method using hall sensors. But each system has its own short-comings: the synchronous motor has a larger measurement error than the magnetic compass and magnetic compass is weak for the external disturbances such as fluctuation of the vessel. To compensate these short-comings, this paper proposes a new compensation algorithm for the fluctuation errors according to the external interference and the unexpected movement of the vessel along the roll and pitch directions. The proposed system is implemented with the dual compasses and a synchronous motor. The proposed independent power generation system can be operated by itself and can raise the efficiency of the wind power generation systems of 30 ~ 400 W installed along the vertical and horizontal axes. The proposed system also realizes the efficient and reliable power production system by the MPPT algorithm for the real-time recognition of the wind direction and velocity. An advanced switching algorithm for the battery charging system has been also proposed. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.