• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.239-246
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• 2005

In this paper. we generate a virtual right image corresponding to the input left image by using given RGB texture data and 8 bit gray scale depth data. We first transform the depth data to disparity data and then produce the virtual right image with this disparity. We also proposed a stereo image synthesis algorithm which is adaptable to a viewer's position and an real-time processing algorithm with a fast LUT(look up table) method. Finally, we could synthesize a total of eleven stereo images with different view points for SD quality of a texture image with 8 bit depth information in a real time.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4759-4780
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• 2017

Full Dimension multiple input multiple output (FD-MIMO) architecture employs a planar array design at the Base Station (BS) to provide high order multi-user MIMO (MU-MIMO) via simultaneous data transmission to large number of users. With FD-MIMO, the BS can also adjust the beam direction in both elevation and azimuth direction to concentrate the energy on the user of interests while minimizing the interference leakage to co-scheduled users in the same cell or users in the neighboring cells. In a typical highly populated macrocell environment, modelling the elevation angular characteristics of three-dimensional (3D) channel is critical to understanding the performance limits of the FD-MIMO system. In this paper, we study the throughput performance of FD-MIMO system with varying elevation angular spread and inter-element spacing using a 3D spatial channel model. Our results show that for a typical urban scenario, horizontal beamforming with correlated antenna spacing achieves optimal performance but by restricting the spread of elevation angles of departure, elevation beamforming achieves high array gain with wide inter-element spacing. We also realize significant gains due to spatial array processing via modelling the elevation domain and varying the inter-element spacing for both the transmitter and receiver.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.688-698
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• 2016

In this paper, we investigate the achievable sum rate and energy efficiency of downlink massive multiple-input multiple-output antenna systems with zero-forcing precoding, by taking into account the randomness of user locations. Specifically, we propose two types of non-uniform user distributions, namely, center-intensive user distribution and edge-intensive user distribution. Based on these user distributions, we derive novel tight lower and upper bounds on the average sum rate. In addition, the impact of user distributions on the optimal number of users maximizing the sum rate is characterized. Moreover, by adopting a realistic power consumption model which accounts for the transmit power, circuit power and signal processing power, the energy efficiency of the system is studied. In particular, closed-form solutions for the key system parameters, such as the number of antennas and the optimal transmit signal-to-noise ratio maximizing the energy efficiency, are obtained. The findings of the paper suggest that user distribution has a significant impact on the system performance: for instance, the highest average sum rate is achieved with the center-intensive user distribution, while the lowest average sum rate is obtained with the edge-intensive user distribution. Also, more users can be served with the center-intensive user distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2435-2453
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• 2015

Independent component analysis (ICA) is a signal processing technique used for un-mixing of the mixed recorded signals. In wireless communication, ICA is mainly used in multiple input multiple output (MIMO) systems. Most of the existing work regarding the ICA applications in MIMO systems assumed static or quasi static wireless channels. Performance of the ICA algorithms degrades in case of time varying wireless channels and is further degraded if the data block lengths are reduced to get the quasi stationarity. In this paper, we propose an ICA based MIMO transceiver that performs well in time varying wireless channels, even for smaller data blocks. Simulation is performed over quadrature amplitude modulated (QAM) signals. Results show that the proposed transceiver system outperforms the existing MIMO system utilizing the FastICA and the OBAICA algorithms in both the transceiver systems for time varying wireless channels. Performance improvement is observed for different data blocks lengths and signal to noise ratios (SNRs).

• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.47-60
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• 2010

Randomness is a basic security evaluation item for the most cryptographic algorithms. NIST has proposed a statistical test suit for random number generators for cryptographic applications in the process of AES project. However the test suit of NIST is customized to block ciphers which have the same input and output lengths. It needs to revise NIST's test suit for key derivation functions which have multiple output blocks. In this paper we propose a revised method of NIST's statistical randomness test adequate to the most key derivation functions and some experimental results for key derivation functions of 3GSM and NIST.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.313-316
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• 2014

디지털 문화유산 콘텐츠는 실제 문화유산의 경험을 완벽하게 전달할 수는 없지만 디지털 기술의 특성을 이용하여 다양한 부가서비스를 포함함으로써 사용자들에게 재미를 부여하거나 사용자 경험을 극대화할 수 있다. 그런데 기존의 디지털 문화유산 콘텐츠는 대부분 특정 입력 장치에 한정된 사용자 인터랙션을 지원하거나 단일 사용자의 인터랙션에 국한된 경우가 많았다. 본 논문에서는 여러 사용자들이 다양한 종류의 여러 입력 장치를 사용한 인터랙션 정보를 동시에 받아서 다양한 디지털 문화유산 콘텐츠에서 적절하게 처리하여 사용될 수 있는 다중 사용자 입력 및 처리 프레임워크를 소개한다. 이 프레임워크는 서로 다른 입력장치로부터 입력정보를 일반화시켜서 해당 응용프로그램에 전달되어 협력적 인터랙션에 사용할 수 있게 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.338-345
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• 2013

Induction motors play an increasing importance in industrial manufacturing. Therefore, the state monitoring systems also have been considering as the key in dealing with their negative effect by absorbing faulty symptoms in motors. There are numerous proposed systems in literature, in which, several kinds of signals are utilized as the input. To solve the multiple faults problem of induction motors, like the proposed system, the vibration signals is good candidate. In this study, a new signal processing scheme was utilized, which transforms the time domain vibration signal into the spatial domain as an image. Then the spatial features of converted image then have been extracted by applying the dominant neighbourhood structure (DNS) algorithm. In addition, these feature vectors were evaluated to obtain the fruitful dimensions, which support to discriminate between states of motors. Because of reliability, the conventional one-against-all (OAA) multi-class support vector machines (MCSVM) have been utilized in the proposed system as classifier module. Even though examined in severity levels of signal-to-noise ratio (SNR), up to 15dB, the proposed system still reliable in term of two criteria: true positive (TF) and false positive (FP). Furthermore, it also offers better performance than five state-of-the-art systems.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.168-177
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• 2020

Seabed multiple reflections (seabed multiples) are the main cause of misinterpretations of primary reflections in both shot gathers and stack sections. Accordingly, seabed multiples need to be suppressed throughout data processing. Conventional model-driven methods, such as prediction-error deconvolution, Radon filtering, and data-driven methods, such as the surface-related multiple elimination technique, have been used to attenuate multiple reflections. However, the vast majority of processing workflows require time-consuming steps when testing and selecting the processing parameters in addition to computational power and skilled data-processing techniques. To attenuate seabed multiples in seismic reflection data, input gathers with seabed multiples and label gathers without seabed multiples were generated via numerical modeling using the Marmousi2 velocity structure. The training data consisted of normal-moveout-corrected common midpoint gathers fed into a U-Net neural network. The well-trained model was found to effectively attenuate the seabed multiples according to the image similarity between the prediction result and the target data, and demonstrated good applicability to field data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2C
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• pp.86-92
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• 2011

This paper details the downlink performance analysis of an multiple antennas system that combines adaptive beamforming and spatial multiplexing (SM) Multiple Input Multiple Output (MIMO). The combination of MIMO signal processing with adaptive beamforming is applied to WiBro, the South Korean Orthogonal Frequency Division Multiple Access (OFDMA) system that follows the IEEE 802.16e standard. Performance analysis is based on the results of experiments and simulations obtained from a fixed-point simulation testbed. Simulations demonstrate that the MIMO Beamforming OFDMA system improves the required signal to noise ratio (SNR) over the conventional MIMO OFDMA system by 3 dB (QPSK) / 2.5 dB (16-QAM) for the frame error rate (FER) of 1% in the WiBro signal environments. From the implementation of the fixed-point simulation testbed and its experimental results, we verify the feasibility of the MIMO Beamforming technology for realizing a practical WiBro base station.