• The Journal of the Acoustical Society of Korea
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• v.13 no.1E
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• pp.89-95
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• 1994

This paper describes development of a real-time voice dialing system which can recognize around one hundred word vocabularies in speaker independent mode. The voice recognition algorithm in this system is implemented on a DSP board with a telephone interface plugged in an IBM PC AT/486. In the DSP board, procedures for feature extraction, vector quantization(VQ), and end-point detection are performed simultaneously in every 10 msec frame interval to satisfy real-time constraints after detecting the word starting point. In addition, we optimize the VQ codebook size and the end-point detection procedure to reduce recognition time and memory requirement. The demonstration system has been displayed in MOBILAB of the Korean Mobile Telecom at the Taejon EXPO'93.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.77-82
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• 2013

The object tracking method using particle filtering has been proved successful since it is based on the Monte Carlo simulation to estimate the posterior distribution of the state vector that is nonlinear and non-Gaussian in the real-world situation. In this paper, we present two nobel methods that can improve the performance of the object tracking algorithm based on the particle filtering. First one is the feedback method that replace the low-weighted tracking sample by the estimated state vector in the previous frame. The second one is an tracking box correction method to find an confidence interval of back projection probability on the estimated candidate object area. An sample propagation equation is also presented, which is obtained by experiments. We designed well-organized test data set which reflects various challenging circumstances, and, by using it, experimental results proved that the proposed methods improves the traditional particle filter based object tracking method.

• 한국기계연구소 소보
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• s.16
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• pp.127-136
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• 1986

Recently deck crane of multi purpose cargo vessel (MPCV) is designed to posi¬tion in side instead of in the center line of the upper deck with a view to reduce the transportation cost and shipbuilding cost by shortening the length of ship. In this paper, the crane post was at first designed according to the crane maker’s specification and parent ship and the structure is analysed with Finite Ele¬ment Method. Through the careful reviews on the result of analysis, the final design of crane post was modified. The crane post is designed as a cylindrical in upper part and hexagonal in lower part instead of cylindrical on the whole as before. The connecting part of crane post is designed with the form of mixture of the cylinderical and hexagonal. Since the center of cylindrical and hexagonal section are not on the same line, it is expected to have the stress concentration. So, in order to attenuate the concentrated stress on the connecting part, the upper and lower parts was stiffened by inserting plate to enlarge the area of welding. The structure of deck part includes the tank side floor which is depend on the lower structure of the crane post that would support the force of the crane post by placing with 1.5 frame interval of the vertical plate.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.81-88
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• 2011

Mini Double Gears Frame is critical part of PDP and also produces couple hundred thousand every month. In the process of mass production, product inspection is very important process. Double Gear, one of the part of machine, was inspected by human eyes which caused mistakes and slow progress. To achieve the speed and accuracy the system was compensated by vision system which is inspecting automatically. The focus value is measured based on the fact that high contrast images have much high frequency edge information. High frequency term of the image is extracted using the high-pass filter and the sum of the high frequency term is used as the focus value. We used a Gaussian smoothing filter to reduce the noise and then measures the focus value using the modified Laplacian filter called a Sum modified Laplacian Focus values for the various lens positions are calculated and the position with the maximum focus value is decided as the focused position. The focus values calculated in various lens position showed the Gaussian distribution. We proposed a method to estimate the best focus position using the Gaussian curve fitting. Focus values of the uniform interval lens positions are calculated and the values are used to estimate the Gaussian distribution parameters to find the best focus position.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.76-79
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• 2002

Ghost cancelers need to accurately estimate the distortions suffered by transmitted signals on their way to receivers by capturing ghost canceling reference signals in the vertical blanking interval. As ghosts become much severer, sync separation tends to malfunction, making it impossible to acquire measurement data for channel estimation. This paper presents a robust method of acquiring ghost data using their correlation properties, and evaluates its performance through computer simulation. The reference signals are inserted in such a manner that the polarity alternates from one frame to another to remove color bursts and sync signals, and to increase the signal-to-noise ratio as well. As a result, however, they are prone to timing jitters. So a simple yet effective method is proposed that can correct for even fractional time delays. The timing errors are found to be less than about 4% of the sample spacing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.13-14
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• 2008

In this paper, we analyze the electrical characteristics of PV depending on distance among solar cells before and after lamination process. From the result, the PV module's maximum power increases about 3.37% when solar cells's distance is 10mm. And the maximum power increases up to 8.42% when solar cells's maximum distance is 50mm. It is assumed that PV module's surface temperature decreases because of increasing distance between solar cells that would give high power generation. Also, short distance between solar cell and frame result in contamination on glass. When considering reduced maximum power caused by contaminant, from that, we can fabricated PV module of lower cost with high performance.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.4
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• pp.145-150
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• 1989

Preprocessing in speech recognition system is useful, for it reduces some of the complicated procedures required for the final recognition. In this paper, we suggest a new preprocessing algorithm for detecting the intervals of implosive stop sounds. Implosive stop sounds follow vowels in Korean language, and its characteristic is included in the region of vowels. When an implosive stop is pronounced, the velum is quickly colsed, thus its energy decays abruptly and the closure lasts for about 50 to 150 msec. The enegy difference between adjacent frames is chosen as a parameter which represents well the above features.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.48-55
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• 2009

In scalable video coding, MCTF plays an important role for time-scalability and SNR-scalability. But there is image quality decreasing as MCTF level is increased because time interval of each frame is extended so that is hard to find suitable motion vector. In this paper, we propose an algorithm to prevent image quality from decreasing with unsuitable motion vector during MCTF update process using JND. We adapt JND to find errors within blocks of image and set a threshold which is used to add high frequency components during update process. We can overcome time-gap between frames and achieve better image quality through the proposed algorithm.

• Earthquakes and Structures
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• v.1 no.2
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• pp.147-162
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• 2010

The ground acceleration measured at a point on the earth's surface is composed of several waves that have different phase velocities, arrival times, amplitudes, and frequency contents. For instance, body waves contain primary and secondary waves that have high frequency content and reach the site first. Surface waves are composed of Rayleigh and Love waves that have lower phase velocity, lower frequency content and reach the site next. Some of these waves could be of more damage to the structure depending on their frequency content and associated amplitude. This paper models critical earthquake loads for single-degree-of-freedom (SDOF) inelastic structures considering evolution of the seismic waves in time and frequency. The ground acceleration is represented as combination of seismic waves with different characteristics. Each seismic wave represents the energy of the ground motion in certain frequency band and time interval. The amplitudes and phase angles of these waves are optimized to produce the highest damage in the structure subject to explicit constraints on the energy and the peak ground acceleration and implicit constraints on the frequency content and the arrival time of the seismic waves. The material nonlinearity is modeled using bilinear inelastic law. The study explores also the influence of the properties of the seismic waves on the energy demand and damage state of the structure. Numerical illustrations on modeling critical earthquake excitations for one-storey inelastic frame structures are provided.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3165-3181
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• 2019

Spherical videos, which are also called 360-degree videos, have become increasingly popular due to the rapid development of virtual reality technology. However, the large amount of data in such videos is a huge challenge for existing transmission system. To use the existing encode framework, it should be converted into a 2D image plane by using a specific projection format, e.g. the equi-rectangular projection (ERP) format. The existing high-efficiency video coding standard (HEVC) can effectively compress video content, but its enormous computational complexity makes the time spent on compressing high-frame-rate and high-resolution 360-degree videos disproportionate to the benefits of compression. Focusing on the ERP format characteristics of 360-degree videos, this work develops a fast decision algorithm for predicting the coding unit depth interval and adaptive mode decision for intra prediction mode. The algorithm makes full use of the video characteristics of the ERP format by dealing with pole and equatorial areas separately. It sets different reference blocks and determination conditions according to the degree of stretching, which can reduce the coding time while ensuring the quality. Compared with the original reference software HM-16.16, the proposed algorithm can reduce time consumption by 39.3% in the all-intra configuration, and the BD-rate increases by only 0.84%.