• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.464-471
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• 2010

The demand for high quality of multimedia applications, which far surpasses the rapid evolution of transmission and storage technologies, makes better compression coding capabilities ever increasingly more important. In order to provide enhanced video coding performance, this paper proposes an efficient competition-based motion vector coding scheme. The proposed algorithm adaptively forms the motion vector predictors based on the contexts of scene characteristics such as camera motion and nearby motion vectors, providing more efficient candidate predictors than the previous competition-based motion vector coding schemes which resort to the fixed candidates optimized by extensive simulations. Up to 200% of compression gain was observed in the experimental results for the proposed scheme applied to the motion vector selection for skip mode processing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.145-152
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• 2009

Ultra-wideband communication systems for impulse radio have merits that are possible for either high resolution ranging system or radio determination. Conventionally, in order to accomplish these functions, the rapid analog to digital convertor (ADC) is necessary to apply radio determination system operating in time domain. However, considering that low rate - wireless personal area network (LR-WPAN) aims to low-cost hardware implementation, the expensive ADC converting GHz sampling per second is not appropriate. So, this paper introduces the high resolution ranging system operating in frequency domain with using low sampling rate ADC, and a new non-coherent ranging scheme utilizing analog Frequency Modulation (FM) mode for the frequency domain transformation. To verify the superiority of the proposed ranging algorithm working in frequency domain, the suggested IEEE 802.15.4a TG channel model is used to exploit affirmative features of the proposed algorithm with conducting the simulation results.

• Korean Journal of Legislative Studies
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• v.23 no.2
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• pp.37-66
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• 2017

Massive civic protests and consequent presidential impeachment requires a serious revisiting to democratic theories of Korean democracy. This paper explores the strengths and limitations of macro and micro approaches. Changes in democratic realities was manifested on three fronts. First, the rise of new political subject, that is, participants to massive protest. Second, changing nexus between representative institutions and civic protests. Third, parliamentarization of presidential democracy. Specifically macro approach has changed its negative assessment of democracy into positive evaluation. Macro theory has to revisit it's notion of 'minjung' to cope with the rise of new subject. Also macro approach has to struggle with the declining role of civic organizations and political activists. Micro approach has to deal with new mode of networking among citizens and to unravel the evolving relation between democratic institutions and civic protests. In sum, theories need to expand the analytic scope, to revitalize analytic tools and to rebalance value judgment and analytical efforts.

• Journal of the Korea Society of Computer and Information
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• v.27 no.8
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• pp.143-149
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• 2022

Since patent documents contain detailed results of research and development technologies, many studies on various patent analysis methods for effective technology analysis have been conducted. In particular, research on quantitative patent analysis by statistics and machine learning algorithms has been actively conducted recently. The most used patent data in quantitative patent analysis is technology keywords. Most of the existing methods for analyzing the keyword data were models based on the Gaussian probability distribution with random variable on real space from negative infinity to positive infinity. In this paper, we propose a model using gamma probability distribution to analyze the frequency data of patent keywords that can theoretically have values from zero to positive infinity. In addition, in order to determine the regression equation of the gamma-based regression model, two-mode network is constructed to visualize the technological association between keywords. Practical patent data is collected and analyzed for performance evaluation between the proposed method and the existing Gaussian-based analysis models.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3866-3873
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• 2000

In this paper, we investigates the long-term memory and the Correct answer rate of the foreign exchange data (Yen/Dollar) that is one of economic time series, There are many cases where two kinds of fractal dimensions exist in time series generated from dynamical systems such as AR models that are typical models having a short terrr memory, The sample interval separating from these two dimensions are denoted by kcrossover. Let the fractal dimension be $D_1$ in K < $k^{crossover}$,and $D_2$ in K > $k^{crossover}$ from the statistics mode. In usual, Statistic models have dimensions D1 and D2 such that $D_1$ < $D_2$ and $D_2\cong2$ But it showed a result contrary to this in the real time series such as NIKKEL The exchange data that is one of real time series have relation of $D_1$ > $D_2$ When the interval between data increases, the correlation between data increases, which is quite a peculiar phenomenon, We predict exchange data by neural networks, We confirm that $\beta$ obrained from prediction errors and D calculated from time series data precisely satisfy the relationship $\beta$ = 2-2D which is provided from a non-linear model having fractal dimension, And We identified that the difference of fractal dimension appeaed in the Correct answer rate.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.705-715
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• 2016

The purpose of this research is to analyze elementary students' attention characteristics through attention test and eye tracking on real science classes. The SMI's ETG(eye tracker glasses) mobile eye tracker was used to analyze the attention process of elementary students'. The sampling rate of the ETG is 30Hz. The participants of attention test were elementary 155 6th-grade elementary students and the participants for the eye-tracker were six 6th-grade male students. The eye movements were analyzed using the 'BeGaze Mobile Video Analysis Package' program. The results of this research are as follows. First, the attention test results of elementary students showed high correlation between selective attention and sustained attention (.85) and low correlation between selective attention and self-regulation (.32). Second, the attention types of elementary students were divided into four; attention, inattention, easygoing and hasty. Third, elementary students' attention were divided into top-down, bottom-up, default mode network through analysis of elementary students′ eye-movements during real science classes. Also their attention shift occurred frequently due to various reasons in real class situation. There were three reasons that made elementary students fail to handle knowledge-dependent top-down attention; 1) the cognitive failure of target caused by failing to focus attention, 2) the absence of prior knowledge on target object, 3) the analogical failure of prior knowledge. Finally, elementary students' attention process were schematized based on the analysis of students' eye movements and attention test. This research is expected to be utilized as basic data for developing effective teaching strategies, teaching-learning models and instructional materials.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.52-59
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• 2007

In this paper, we analyzed and measured implant isolation characteristics for a 1.25 Gbps monolithic integrated hi-directional (M-BiDi) optoelectronic system-on-a-chip, which is a key component to constitute gigabit passive optical networks (PONs) for a fiber-to-the-home (FTTH). Also, we derived an equivalent circuit of the implant structure under various DC bias conditions. The 1.25 Gbps M-BiDi transmit-receive SoC consists of a laser diode with a monitor photodiode as a transmitter and a digital photodiode as a digital data receiver on the same InP wafer According to IEEE 802.3ah and ITU-T G.983.3 standards, a receiver sensitivity of the digital receiver has to satisfy under -24 dBm @ BER=10-12. Therefore, the electrical crosstalk levels have to maintain less than -86 dB from DC to 3 GHz. From analysed and measured results of the implant structure, the M-BiDi SoC with the implant area of 20 mm width and more than 200 mm distance between the laser diode and monitor photodiode, and between the monitor photodiode and digital photodiode, satisfies the electrical crosstalk level. These implant characteristics can be used for the design and fabrication of an optoelectronic SoC design, and expended to a mixed-mode SoC field.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.71-76
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• 2017

The electrical behavior and flexibility of the screen printed Ag circuits were investigated with infrared radiation sintering times and sintering temperatures. Electrical resistivity and radio frequency characteristics were evaluated by using the 4 point probe measurement and the network analyzer by using cascade's probe system, respectively. Electrical resistivity and radio frequency characteristics means that the direct current resistance and signal transmission properties of the printed Ag circuit. Flexibility of the screen printed Ag circuit was evaluated by measuring of electrical behavior during IPC sliding test. Failure mode of the Ag printed circuits was observed by using field emission scanning electron microscope and optical microscope. Electrical resistivity of the Ag circuits screen printed on Pl substrate was rapidly decreased with increasing sintering temperature and durations. The lowest electrical resistivity of Ag printed circuit was up to $3.8{\mu}{\Omega}{\cdot}cm$ at $250^{\circ}C$ for 45 min. The crack length arisen within the printed Ag circuit after $10{\times}10^4$ sliding numbers was 10 times longer than that of after $2.5{\times}10^4$ sliding numbers. Measured insertion loss and calculated insertion loss were in good agreements each other. Insertion loss of the printed Ag circuit was increased with increasing the number of sliding cycle.

• Journal of Broadcast Engineering
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• v.25 no.2
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• pp.265-274
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• 2020

Free-viewpoint video service is a technology that allows users to watch at any angle, location and distance through interaction. In this paper, the free-viewpoint video services are defined in four viewing modes: Inward view, outward view, 3D object view and first person view. And we developed and implemented a new integrated program that plays all the suggested views. In the contents of girl band performances and basketball games, multi-view cameras suitable for each viewing mode are installed to acquire media, and data stored on the server is streamed over the network, making it available for viewing. Users can freely choose four viewing modes, space location, angle and so on, and the media data such as images and sounds are provided to them by rendering appropriately for the selected the viewpoint. Our system is expected to be a scalable free-viewpoint video service player as well as provide users with immersion and presence by combining various viewing modes.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.127-135
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• 2008

Generally, optimum shortest path algorithms adopt single attribute objective among several attributes such as travel time, travel cost, travel fare and travel distance. On the other hand, multi-objective shortest path algorithms find the shortest paths in consideration with multi-objectives. Up to recently, the most of all researches about multi-objective shortest paths are proceeded only in single transportation mode networks. Although, there are some papers about multi-objective shortest paths with multi-modal transportation networks, they did not consider transfer problems in the optimal solution level. In particular, dynamic programming method was not dealt in multi-objective shortest path problems in multi-modal transportation networks. In this study, we propose a multi-objective shortest path algorithm including dynamic programming in order to find optimal solution in multi-modal transportation networks. That algorithm is based on two-objective node-based label correcting algorithm proposed by Skriver and Andersen in 2000 and transfer can be reflected without network expansion in this paper. In addition, we use non-dominated paths and tree sets as labels in order to improve effectiveness of searching non-dominated paths. We also classifies path finding attributes into transfer and link travel attribute in limited transit networks. Lastly, the calculation process of proposed algorithm is checked by computer programming in a small-scaled multi-modal transportation network.