• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1983-1989
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• 2005

Industrial robots are powerful, extremely accurate multi-jointed systems, but they are heavy and highly rigid because of their mechanical structure and motorization. Therefore, sharing the robot working space with its environment is problematic. A novel pneumatic artificial muscle actuator (PAM actuator) has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. Its main advantages are high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks. The PAM is undoubtedly the most promising artificial muscle for the actuation of new types of industrial robots such as Rubber Actuator and PAM manipulators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads in order to realize a human-friendly therapy robot To overcome these problems a novel controller, which harmonizes a phase plane switching control method with conventional PID controller and the adaptabilities of neural network, is newly proposed. In order to realize satisfactory control performance a variable damper - Magneto-Rheological Brake (MRB) is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control using neural network brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control using neural network and without regard for the changes of external inertia loads.

• Journal of The Korean Association of Information Education
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• v.24 no.3
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• pp.233-241
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• 2020

This study has developed and applied an elementary EPL education program centered on execution time as an educational method for improving Computational thinking of elementary school students, and then its effect has been verified. The education program was developed based on the results of preliminary demand analysis conducted on 48 elementary school students. In order to verify the effectiveness of the education program, 25 students were asked to participate in the class of elementary school students on a seven hours for six days. Using the "Korea Bebras Challenge 2018", educational effects were analyzed through the results of pre- and post-mortem examinations, and the analysis showed that elementary EPL education centered on performance time was effective in improving computational thinking of elementary school students

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.9-14
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• 2020

In this paper, Qualification Model of frequency synthesizer is designed for X-band SAR system and performed electrical and environment test. Designed frequency synthesizer generate 13.65 GHz with very low phase noise performance. The integrated phase noise from 10Hz to 1MHz is -37.91 dBc. IRF performances are analyzed according to phase noise and jitter. Also, thermal and structure analysis are achieved for stable operation in space environment. Designed frequency synthesizer is consist of 2 modules of 6U size and generate L-band, C-band, Ku-band. The result of this study would enhance the design ability of RF module and help the frequency synthesizer design for SAR payload system.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.87-94
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• 2018

Intelligent transportation systems are one of the most important new forms of infrastructure on domestic roads, and is a system that makes possible the most efficient movement of vehicles on a road. The High Pass system, which is a domestic intelligent transportation system, started a little later than in other countries but developed at a rapid pace. With the recent introduction of smart tolling technology, it provided an opportunity to stop and review the tolling system. This study aims to investigate the driving method and results of LDCC for domestic smart towing through case study. Unlike other companies, Lotte Data Communication Company has long invested in payment systems. It has little experience investing in infrastructure, but participated in the Smart Toll System at the Gwangan Bridge in cooperation with the Busan City government, to lead the development of intelligent transportation systems. LDCC, which has made new investments, not only exceeded its existing core competencies, but also upgraded Korea's tolling system's ability to reduce greenhouse gas emissions and improved its financial performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.8-16
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• 2010

NAND multilevel cell (MLC) flash memory is widely issued because it can increase the capability of storage by storing two or more bits to a single cell. However if a number of levels in a cell increases, some physical features like cell to cell interference result cell voltage shift and it is known that a VT shift is unidirectional. To reduce errors by the effects, we can consider error correcting codes(ECC) or signal processing methods. We focus signal processing methods for the cell to cell interference voltage shift effects and propose the algorithms which reduce the effects of the voltage shift by estimating it and making level read voltages be adaptive. These new algorithms can be applied with ECC at the same time, therefore these algorithms are efficient for MLC error correcting ability. We show the bit error rate simulation results of the algorithms and compare the performance of the algorithms.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.21-29
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• 2011

This paper presents a method that estimates distance and velocity of an object with reliability regardless of maneuver status of the target in stereo vision system. A stereo vision system can calculate a distance with disparity from left and right images. However, the distance estimation error may occur due to quantization error of image pixel. A sub-pixel interpolation method minimizes the quantization error and estimates accurate disparity with real value. Extended Kalman filter (EKF) was used to minimize the error covariance and estimate the object's velocity. However, divergence problem occurs due to model uncertainty when a target maneuvers highly, which makes the estimation error increase. In this paper, we propose a virtual model extended Kalman filter (VMEKF) method that minimizes the processing time and provides reliable estimation ability regardless of maneuver status. Computer simulations and experimental results in real road environments demonstrate that the proposed method gives a reliable estimation performance and reduces processing time under various maneuver status while comparing other estimation filters.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.85-91
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• 2007

Satellite Digital Multimedia Broadcasting (S-DMB) is the digital convergence service of broadcasting and communication for mobility and portability. Broadcasting service of S-DMB can be taken by the mobile phone or vehicle terminals anytime and anywhere. S-DMB system is currently providing 11 video channels and 26 audio channels. As the demand of multimedia service is recently increasing, S-DMB system needs high quality and new contents service. Therefore we need to make efficient S-DMB with more channel ability and high transmission quality. In this paper, we propose new S-DMB system that can be applied to powerful channel coding scheme and hierarchical 8-PSK(8-Phase Shift Keying) modulation with Backwards Compatibility modes that simultaneously can support both current and new system. And we analyze the performance of current S-DMB system and verify a possibility of advanced S-DMB through computer simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.148-155
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• 2014

In this paper a commute time embedding is implemented by organizing patches according to the graph-based metric, and its properties are investigated via changing the number of nodes on the graph.. It is shown that manifold embedding methods generate the intrinsic geometric structures when waveforms such as speech or music instrumental sound signals are embedded on the low dimensional Euclidean space. Basically manifold embedding algorithms only project the training samples on the graph into an embedding subspace but can not generalize the learning results to test samples. They are very effective for data clustering but are not appropriate for classification or recognition. In this paper a commute time guided transform is adopted to enhance the generalization ability and its performance is analyzed by applying it to the classification of 6 kinds of music instrumental sounds.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.18-24
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• 2014

In this paper, the optimum placement of airborne line-of-sight (LOS) datalink directional antenna to minimize the datalink loss within the operation range of unmanned aerial vehicle (UAV) is analyzed by using the electromagnetic (EM) simulation. In quick banking of UAV, the datalink loss is occurred due to the electromagnetic distortion and transmission loss by the fuselage blockage. In general, the banking angle of UAV is limited to prevent the datalink loss. However, in this case, there is the problem that the mission performance ability is largely limited by the banking radius increase. To solve this problem, the optimum placement to mount the airborne LOS datalink 1-axis directional antenna on both the top and bottom surfaces of fuselage is analyzed by using EM simulation. The 1-axis antenna with large vertical beamwidth is used because the banking angle of UAV is dependent on the vertical beamwidth of antenna. Also, there is the benefit to reduce largely the weight because the 1-axis antenna can be mounted instead of the 2-axis one.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.121-130
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• 2009

In this paper, Gaussian probability distribution model based multi-sensor data fusion algorithm is proposed for a vehicular location awareness system. Conventional vehicular location awareness systems are operated by GPS (Global Positioning System). However, the conventional system is not working in the indoor of building or urban area where the receiver is difficult to receive the signal from satellites. A method which is combined GPS and UWB (Ultra Wide-Band) has developed to improve this problem. However, vehicular is difficult to receive seamless location information since the measurement systems by both GPS and UWB convert the vehicle's movement information separately at each sensor. In this paper, normalized probability distribution model based Hybrid UWB/GPS is proposed by utilizing GPS location data and UWB sensor data. Therefore the proposed system provides information with seamless and location flexible properties. The proposed system tested by Ubisense and Asen GPS in the $12m{\times}8m$ outdoor environments. As a result, the proposed system has improved performance for accurateness and connection ability between devices to support various CNS (Car Navigation System).