• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2157-2163
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• 2010

This paper includes the study of DOA(Direction of Arrival). CVDF(Correlative Vector Direction Finding) algorithm using at the phase difference each antenna needs to obtain ideal sinusoidal phase difference patterns. However, the phase difference patterns of circular array antennas may be interfered on a specific frequency band and to particular angle. The effect of installing each array antenna circularly and the effect of the interference by center pole (located in the center of a circular array antennas) may distort the phase difference patterns. This paper propose how to change the combination of antennas to measure phase difference patterns in real-time and how to use antenna beam patterns for minimizing the degradation phenomena with old CVDF algorithm. According to the test result, the capability of direction finding is improved.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.126-131
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• 2014

This paper discusses stability of new simplified sensorless vector control systems of induction motors (IM). The simplified sensorless systems estimate the flux angle by using the output voltage of d-axis PI current controller to achieve the q-axis flux zero. Two simplified sensorless systems are studied. The difference of two systems is the presence or absence of a q-axis PI current controller. The systems stability is compared by deriving linear state equations and showing root loci and unstable regions. Furthermore, transient responses and experiment results make clear the stability of the proposed system.

• Journal of Integrative Natural Science
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• v.12 no.4
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• pp.105-115
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• 2019

In this paper, a prediction system is proposed to control the brightness of smart street lamps by predicting the moving path through the reduction of consumption power and information of pedestrian's past moving direction while meeting the function of existing smart street lamps. The brightness of smart street lamps is adjusted by utilizing the walk tracking vector and soft hand-off characteristics obtained through the motion sensing sensor of smart street lamps. In addition, the motion vector is used to analyze and predict the pedestrian path, and the GPU is used for high-speed computation. Pedestrians were detected using adaptive Gaussian mixing, weighted difference imaging, and motion vectors, and motions of pedestrians were analyzed using the extracted motion vectors. The preprocessing process using linear interpolation is performed to improve the performance of the proposed prediction system. Fuzzy prediction system and neural network prediction system are designed in parallel to improve efficiency and rough set is used for error correction.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.139.4-139
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• 2001

The thesis propose the sensorless vector control method that estimates the rotor speed using stator current. The estimated speed is used as feedback in a vector control system. The conventional MRAS structure has a problem the error output is decreasing as estimated speed error is increasing and the estimation performance is not robust when mutual inductance has been changed. In the proposed method, error output is proportional to estimated speed error. The described technique is less complex, robust to variations of mutual inductance. This new method can achieve much wider bandwidth speed control than that of the conventional MRAS structure.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.585-591
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• 1998

It is proposed a new compensation method in the rotor time constant of indirect vector controlled induction motor. The proposed scheme is an on-line method using the stator current error that is the difference between current command and estimated current calculated from terminal voltages and currents. As the current error becomes to zero, the rotor time constant in the vector controller approaches the real value. The proposed method shows good performances in the transient region as well as in the steady state region regardless of load torque variation, and it is verified by the computer simulation using SIMULINK in Matlab.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.27-30
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• 1999

A spatio-temporal vector channel model is introduced for the position location (PL) estimation problem for CDMA cellular system environment. Two common ways for the PL make use of the AOA (Angle Of Arrival) and TDOA (Time Difference Of Arrival) from a subscriber to the multiple sensors (base stations). In this paper, we applied the derived vector channel to simulate the multipath channel for the angle of the signal arrival in CDMA systems. Cross-correlation method is a good candidate among other direction finding algorithms available in literature, especially in wideband modulation as in the CDMA system. The PL estimation errors are evaluated for different channels, which are obtained as a parameter of scattering radius of the suggested model. We noted that the number of sensors (base-stations) are related to the PL errors in favor of the available data.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.388-392
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• 2014

This paper proposes an early termination method of a block vector search for fast encoding of high efficiency video coding (HEVC) screen content coding (SCC). In the proposed algorithm, two blocks indicated by two block vector predictors (BVPs) were first employed as an intra block copy (IBC) search. If the sum of absolute difference (SAD) value of the block is less than a threshold defined empirically, an IBC BV search is terminated early. The initial threshold for early termination is derived by statistical analysis and it can be modified adaptively based on a quantization parameter (QP). The proposed algorithm is evaluated on SCM-2.0 under all intra (AI) coding configurations. Experimental results show that the proposed algorithm reduces IBC BV search time by 29.23% on average while the average BD-rate loss is 0.41% under the HEVC SCC common test conditions (CTC).

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.17-22
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• 1997

The performances of the CRAYT3E and CRAYC90 were compared in the point of aerodynamics. The CRAYC90 with and without the highest vector option was run, respectively. The CRAYT3E was run with various processors (from 1pe to 32pes). The communication utilities of MPI and SHMEM were used to inform the boundary data to the other processors. The DADI Euler solver, which is implicit scheme and use central difference method, was used. The domain decomposition method was also used. As the result, the CRAYC90 with the highest vector option is 5.7 times faster than the CRAYT3E with 1 processor. However, because of the scalability of the CRAYT3E, the CRAYT3E with more than 6 processors is faster than CRAYC90. In case that 32 processors used, the CRAYT3E is 6 times faster than CRAYC90 with the highest vector option.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.231-231
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• 2000

It is proposed that a novel method which can compensate the time delay occurs in overall system, when voltage and current is measured, owing to LPF, hysteresis control inverter and microprocessor program computation time. The Proposed scheme estimates the time delay using the difference between Q-axis stator current command and time delayed Q-axis stator current in synchronous reference frame, and compensates the time delay of voltage and current using angular displacement of DQ transformation. The proposed scheme compensates accurately the time delay occurs in overall system. Therefore performance of vector control system is improved highly and it is verified by simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.347-347
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• 2000

Nowadays, the Laser image is used to realize multi-media show for events, an advertising media and 3D simulation, realization of video image and so on. It is a hot issue to realize the laser image like computer graphic image. The image used in laser projector is vector graphic image that is described by linking point to point. A computer makes this continuous vector graphic images so that the image shows as an animation. A control signal converted by a computer makes the laser projector draw image. Two motors and universal joint are used to realize 2D laser image in this study. Developing a controller applied Look-ahead algorithm and software to interface with personal computer, This study is the chief aim of improving difference of moving velocity that is appeared from edge of vector graphic image and disparity of graphic density.