• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.87-94
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• 2005

3D image mosaicking is useful for 3D visualization of the roadside scene of urban area by projecting 2D images to the 3D planes. When a sequence of images are filmed from a side-looking video camera passing long distance areas, the ghost effect in which same objects appear repeatively occurs. To suppress such ghost effect, the long distance range areas are detected by using the distance between the image frame and the 3D coordinate of tracked optical flows. The ghost effects are suppressed by projecting the part of image frames onto 3D multiple planes utilizing vectors passing the focal point of frames and a virtual focal point. The virtual focal point is calculated by utilizing the first and last frames of the long distance range areas. We demonstrate algorithm that creates efficient 3D Panoramic mosaics without the ghost effect at the long distance area.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.6
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• pp.55-62
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• 2005

This paper proposes a method to recognize a face using DCT/LDA where LDA is applied to DCT coefficients of an input face image. In the proposed method, SSS problem of LDA due to less number of training data than the size of feature space can be avoided by expressing an input image in low dimensional space using DCT coefficients. In terms of the recognition rate, both the proposed method and the PCA/LDA method have shown almost equal performance while the training time of the proposed method is much shorter than the other. This is because DCT has the fixed number of basis vectors while the property of energy compaction rate is similar to that of PCA. Although depending on the number of coefficients employed for the recognition, the experimental results show that the performance of the proposed method in terms of recognition rate is very comparable to PCA/LDA method and other DCT/LDA methods, and it can be trained 13,000 times faster than PCA/LDA method.

• Journal of Digital Contents Society
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• v.8 no.4
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• pp.441-449
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• 2007

In video coding, motion estimation is a process to estimate the pixel of the current frame from the reference frame, which affects directly the predictive quality and the encoding time. This paper is related to AHHS(Adaptive Hierarchical Hexagon Search) using spatio-temporal motion activity for fast motion estimation. The proposed method defines the spatio-temporal motion activity of the current macroblock using the motion vectors of its spatio-temporally adjacent macroblocks, and then conventional AHS(Adaptive Hexagon Search) is performed if the spatio-temporal motion activity is lower, otherwise, hierarchical hexagon search is performed on a multi-layered hierarchical space constructed by multiple sub-images with low frequency in wavelet transform. In the paper, based on computer simulation results for multiple video sequences with different motion characteristics, the performance of the proposed method was analysed and assessed in terms of the predictive quality and the computational time. Experimental results indicate that the proposed method is both suitable for (quasi-) stationary and large motion searches. The proposed method could keep the merit of the adaptive hexagon search capable of fast estimating motion vectors and also adaptively reduce the local minima occurred in the video sequences with higher spatio-temporal motion activity.

• The Journal of the Acoustical Society of Korea
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• v.35 no.2
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• pp.110-117
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• 2016

Passive sonar systems detect and classify the target by analyzing the radiated noises from vessels. If multiple noise sources exist within the sonar detection range, it gets difficult to classify each noise source because mixture of noise sources are observed. To overcome this problem, a beamforming technique is used to separate noise sources spatially though it has various limitations. In this paper, we propose a new method that uses a FDICA (Frequency Domain Independent Component Analysis) to separate noise sources from the mixture. For experiments, each noise source signal was synthesized by considering the features such as machinery tonal components and propeller tonal components. And the results of before and after separation were compared by using LOFAR (Low Frequency Analysis and Recording), DEMON (Detection Envelope Modulation On Noise) analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.249-253
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• 2006

We propose a new beamforming algorithm, which is based on simplex downhill optimization method in the presence of pilot channels in cdma2000 reverse-link, for the rake structure antenna array in DS/CDMA communication system. Our approach uses the desired signal(pilot) covariance matrix and the interference covariance matrix. The beamforming weights are made according to maximum SINR criteria using simplex downhill optimization procedure. Our proposed scheme provides lower computational load, better convergence speed, better performance than existingadaptive beamforming algorithm. The simplex downhill method is well suited to finding the optimal or sub-optimal weight vector, since they require only the value of the deterministic function to be optimized. The rake beamformer performances are also evaluated under several set of practical parameter values with regard to spatial channel model. We also compare the performance between conventional rake receiver and the proposed one under same receiving power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.146-150
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• 1999

On the advent of digital era, ECDIS has emerged as a new navigation aid that should result in significant benefits to safe navigation. More than simply a graphics display, ECDIS is a new concept navigation system capable of providing integrated information of geographical and texual data. As an official vector data for ECDIS, ENC consists of spatial and feature data to describe objects in form of points, lines and areas. IHO published International Standards for ENC, such as S-52(Specification for Chart Content and Display Aspects of ECDIS and S-57(IHO Transfer Standard for Digital Hydrographic Data). This paper deals with the implementation of an EUC representation system which meets S-52 presentation specification and S-57 transfer standards by analyzing S-57 data structures and converting then to an appropriate internal data structures and representing them onto screen adopting S-52 presentation specification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.951-954
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• 2005

This paper presents a study on the accuracy position Controller design for the Composite Smoke Bomb Rotational driving system using a BLDC servo motor. Function of Smoke Bomb is blind in the enermy's sight so that need to high response. The BLDC servo motor controller was designed with DSP(TMS320VC33), IGBT(Insulated Gate Bipolar. Transistor), IGBT gate driver and CPLD(EPM7128). This paper implements those control with vector control and MIN-MAX PWM. Vector control requires information about rotor positions, a resolver should be used to achieve that. The main controller is implemented with a TMS320VC33 high performance floating-point DSP(Digital Signal Process) and PWM Generator is embodied using EPM7128.

• Journal of Navigation and Port Research
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• v.26 no.5
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• pp.543-548
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• 2002

It has been known that the DCMP(Directionally Constrained Minimization of Power) and the ZF(Zero Forcing) can improve the SINR performance of an array antenna system by using spatial signature of wireless channel. This paper analyzes the performance of DCMP and ZF in multiple scattering environments. To obtain the spatial signature of wireless channel. both DOA(Directional of Arrival) and AS(Angular spread) of the received signals were estimated by using ESPRIT. The performance of the DCMP and the ZF was analyzed theoretically. By computer simulation of SINR performance was evaluated.

• Journal of the Korean Society for information Management
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• v.27 no.2
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• pp.225-239
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• 2010

This study aims to answer whether social tagging through user collaboration could be utilized for the creation of digital knowledge of the web, and whether we could verify the quality and efficacy of social tagging to obtain benefits from it. In particular, this paper examines the inter-indexer consistency of social tagging in comparison to professional indexing. It employs two different similarity measures, both of which are based on the Vector Space Model to deal with numerous indexers. It contributes to the utilization of social tagging in the organization of the web, and encourages to adopt social knowledge in developing suitable vocabularies for resources newly generated in the digital library environment. Furthermore, the comparative analysis with two different measures produced more credible results by illustrating a similar pattern of indexing tendency in both measures.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.434-445
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• 2004

Motion Estimation is an essential module in video encoders based on international standards such as H.263 and MPEG. Many fast motion estimation algorithms have been proposed in order to reduce the computational complexity of a well-known full search algorithms(FS). However, these fast algorithms can not work efficiently in DSP processors recently developed for video processing. To solve for this. we propose an efficient motion estimation scheme optimized in the DSP processor like Philips TM1300. A motion vector predictor is pre-estimated and a small search range is chosen in the proposed scheme using strong motion vector correlation between a current macro block (MB) and its neighboring MB's to reduce computation time. An MPEG-4 SP@L3(Simple Profile at Level 3) encoding system is implemented in Philips TM1300 to verify the effectiveness of the proposed method. In that processor, we can achieve better performance using our method than other conventional ones while keeping visual quality as good as that of the FS.