• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.142-148
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• 2008

Though a deblocking filter of H.264/AVC provides enhanced image quality by removing blocking artifact on block boundary, the complex filtering operation on this process is a dominant factor of the whole decoding time. In this paper, we designed an ASIP to accelerate deblocking filter operation with the proposed instruction set. We designed a processor based on a MIPS structure with LISA, simulated a deblocking later model, and compared the execution time on the proposed instruction set. In addition, we generated HDL model of the processor through CoWare's Processor Designer and synthesized with TSMC 0.25um CMOS cell library by Synopsys Design Compiler. As the result of the synthesis, the area and delay time increased 7.5% and 3.2%, respectively. However, due to the proposed instruction set, total execution performance is improved by 18.18% on average.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1
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• pp.11-18
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• 2002

In this paper, a gain-adapted speech recognition method in noise is developed in the time domain. Noise is assumed to be colored. To cope with the notable nonstationary nature of speech signals such as fricative, glides, liquids, and transition region between phones, the nonstationary autoregressive (NAR) hidden Markov model (HMM) is used. The nonstationary AR process is represented by using polynomial functions with a linear combination of M known basis functions. When only noisy signals are available, the estimation problem of noise inevitably arises. By using multiple Kalman filters, the estimation of noise model and gain contour of speech is performed. Noise estimation of the proposed method can eliminate noise from noisy speech to get an enhanced speech signal. Compared to the conventional ARHMM with noise estimation, our proposed NAR-HMM with noise estimation improves the recognition performance about 2-3%.

• Atmosphere
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• v.17 no.1
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• pp.55-68
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• 2007

Future climate changes over East Asia are projected by anthropogenic forcing of greenhouse gases and aerosols using ECHO-G/S (ECHAM4/HOPE-G). Climate simulation in the 21st century is conducted with three standard SRES scenarios (A1B, B1, and A2) and the model performance is assessed by the 20th Century (20C3M) experiment. From the present climate simulation (20C3M), the model reproduced reliable climate state in the most fields, however, cold bias in temperature and dry bias of summer in precipitation occurred. The intercomparison among models using Taylor diagram indicates that ECHO-G/S exhibits smaller mean bias and higher pattern correlation than other nine AOGCMs. Based on SRES scenarios, East Asia will experience warmer and wetter climate in the coming 21st century. Changes of geographical patterns from the present to the future are considerably similar through all the scenarios except for the magnitude difference. The temperature in winter and precipitation in summer show remarkable increase. In spite of the large uncertainty in simulating precipitation by regional scale, we found that the summer (winter) precipitation at eastern coast (north of $40^{\circ}N$) of East Asia has significantly increased. In the 21st century, the warming over the continents of East Asia showed much more increase than that over the ocean. Hence, more enhanced (weakened) land-sea thermal contrast over East Asia in summer (winter) will cause strong (weak) monsoon. In summer, the low pressure located in East Asia becomes deeper and the moisture from the south or southeast is transported more into the land. These result in increasing precipitation amount over East Asia, especially at the coastal region. In winter, the increase (decrease) of precipitation is accompanied by strengthening (weakening) of baroclinicity over the land (sea) of East Asia.

• Journal of the Korean Vacuum Society
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• v.21 no.3
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• pp.121-129
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• 2012

RF biased inductively coupled plasma (ICP) is widely used in semiconductor and display etch processes which are based on vacuum science. Up to now, researches on how rf-bias power affects have been focused on the controls of dc self-bias voltages. But, effect of RF bias on plasma parameters which give a crucial role in the processing result and device performance has been little studied. In this work, we studied the correlation between the RF bias and plasma parameters and the recent published results were included in this paper. Plasma density was changed with the RF bias power and this variation can be explained by simple global model. As the RF bias was applied to the ICP, increase in the electron temperature from the electron energy distribution was measured indicating electron heating. Plasma density uniformity was enhanced with the RF bias power. This study can be helpful for the control of the optimum discharge condition, as well as the basic understanding for correlation between the RF bias and plasma parameters.

• Journal of KIISE:Software and Applications
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• v.34 no.9
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• pp.804-816
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• 2007

Sample training data for machine learning often contain irrelevant information or redundant concept. It is also the case that the original data may include noise. If the information collected for constructing learning model is not reliable, it is difficult to obtain accurate information. So the system attempts to find relations or regulations between features and categories in the teaming phase. The feature selection is to remove irrelevant or redundant information before constructing teaming model. for improving its performance. Existing feature selection methods assume that the distribution of documents is balanced in terms of the number of documents for each class and the length of each document. In practice, however, it is difficult not only to prepare a set of documents with almost equal length, but also to define a number of classes with fixed number of document elements. In this paper, we propose a new feature selection method that considers the impurities among the words and unbalanced distribution of documents in categories. We could obtain feature candidates using the word impurity and eventually select the features through unbalanced distribution of documents. We demonstrate that our method performs better than other existing methods via some experiments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.65-71
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• 2007

Doherty amplifier has more efficiency and distortion than general amplifier. These distortion classified amplitude distortion and phase distortion, memory effect distortion. This paper reports on an attempt to investigate, model and quantity the contribution of the electrical nonlinearity effects and the thermal memory effects to a doherty amplifier's distortion generation and suggests thermal memory effect compensator for pre-distorter. Also this paper reports on the development of an accurate dynamic expression of the instantaneous junction temperature as a function of the instantaneous dissipated power. The parameters of suggested model suppress thermal memory effects doherty amplifier with pre-distorter. Pre-distorter with electrothermal memory effect compensator for doherty amplifier enhanced ACLR performance about 22 dB than general doherty amplifier. Experiment results were mesured by 50W LDMOS Doherty amplifier and pre-distorter with electrothermal memory effect compensator was simulated by ADS.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.88-102
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• 2016

This paper considers the allocation and engagement scheduling problem of interceptor missiles, and the problem was formulated by using MIP (mixed integer programming) in the previous research. The objective of the model is the maximization of total intercept altitude instead of the more conventional objective such as the minimization of surviving target value. The concept of the time window was used to model the engagement situation and a continuous time is assumed for flying times of the both missiles. The MIP formulation of the problem is very complex due to the complexity of the real problem itself. Hence, the finding of an efficient optimal solution procedure seems to be difficult. In this paper, an efficient genetic algorithm is developed by improving a general genetic algorithm. The improvement is achieved by carefully analyzing the structure of the formulation. Specifically, the new algorithm includes an enhanced repair process and a crossover operation which utilizes the idea of the PSO (particle swarm optimization). Then, the algorithm is throughly tested on 50 randomly generated engagement scenarios, and its performance is compared with that of a commercial package and a more general genetic algorithm, respectively. The results indicate that the new algorithm consistently performs better than a general genetic algorithm. Also, the new algorithm generates much better results than those by the commercial package on several test cases when the execution time of the commercial package is limited to 8,000 seconds, which is about two hours and 13 minutes. Moreover, it obtains a solution within 0.13~33.34 seconds depending on the size of scenarios.

• Steel and Composite Structures
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• v.34 no.1
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• pp.107-122
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• 2020

Moment resisting stub columns (MRSCs) have increasingly adopted in special moment-resisting frame (SMF) systems in steel building structures, especially in Asian countries. The MRSCs typically provide a lower deformation capacity compared to shear-panel stub columns, a limited post-yield stiffness, and severe strength degradation as adopting slender webs. A new MRSC design with cored configuration, consisting of a core-segment and two side-segments using different steel grades, has been proposed in the study to improve the demerits mentioned above. Several full-scale components of the cored MRSC were experimentally investigated focusing on the hysteretic performance of plastic hinges at the ends. The effects of the depths of the core-segment and the adopted reduced column section details on the hysteretic behavior of the components were examined. The measured hysteretic responses verified that the cored MRSC enabled to provide early yielding, great ductility and energy dissipation, enhanced post-yield stiffness and limited strength degradation due to local buckling of flanges. A parametric study upon the dimensions of the cored MRSC was then conducted using numerical discrete model validated by the measured responses. Finally, a set of model equations were established based on the results of the parametric analysis to accurately estimate strength backbone curves of the cored MRSCs under increasing-amplitude cyclic loadings.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.59-67
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• 2006

In this paper, we propose an effective use of SuperSQL for efficient media publication that utilizes relational databases. SuperSQL is an enhanced SQL processing system that converts data stored in relational databases into a variety or applied formats, such as XML and HTML, as a result or query. In order to integrate various media generators in SuperSQL query processor, we discuss methods to prepare both for new media promptly and for efficient media publication processing system. This research makes two main contributions: (1) it is a study about methods to integrate media generators by combining common processes in SuperSQL query processor, and (2) it introduces the trinity data model, which divide the media generating processes into three aspects, which are value, structure and medium abstraction. We also show the good performance and feasibility of our system.

• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.302-315
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• 2018

Highly non-linear electro-optical transfer function of the Perceptual Quantizer was approximated by a truncated Taylor series, resulting in a closed form solution for luma adjustment. This previous solution is fast and quite suitable for the hardware implementation of luma adjustment, but the approximation error becomes relatively large in the range of 600~3,900 cd/m2 linear light. In order to reduce such approximation error, we propose a new linear model, for which a correction is performed on the position and the slope of line based on the scope of approximation. In order to verify the approximation capability of the proposed linear model, a comparative study on the luma adjustment schemes was conducted using various high dynamic range test video sequences. Via the comparative study, we identified a significant performance enhancement over the previous fast luma adjustment scheme, where a 4.65dB of adjusted luma t-PSNR gain was obtained for a test sequence having a large portion of saturated color pixels.