• Journal of the korean society of oceanography
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• v.32 no.4
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• pp.163-170
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• 1997

Some CMP gathers acquired from shallow marine seismic reflection survey in offshore Korea do not show the hyperbolic trend of moveout. It originated from so-called swell effect of source and streamer, which are towed under rough sea surface during the data acquisition. The observed time deviations of NMO-corrected traces can be entirely ascribed to the swell effect. To correct these time deviations, a residual statics is introduced using Genetic Algorithms (GA) into the swell correction. A new class of global optimization methods known as GA has recently been developed in the field of Artificial Intelligence and has a resemblance with the genetic evolution of biological systems. The basic idea in using GA as an optimization method is to represent a population of possible solutions or models in a chromosome-type encoding and manipulate these encoded models through simulated reproduction, crossover and mutation. GA parameters used in this paper are as follows: population size Q=40, probability of multiple-point crossover P$_c$=0.6, linear relationship of mutation probability P$_m$ from 0.002 to 0.004, and gray code representation are adopted. The number of the model participating in tournament selection (nt) is 3, and the number of expected copies desired for the best population member in the scaling of fitness is 1.5. With above parameters, an optimization run was iterated for 101 generations. The combination of above parameters are found to be optimal for the convergence of the algorithm. The resulting reflection events in every NMO-corrected CMP gather show good alignment and enhanced quality stack section.

• Journal of information and communication convergence engineering
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• v.14 no.4
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• pp.246-251
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• 2016

In this study, we developed a reduced 94 GHz hybrid ring coupler on a GaAs substrate in order to demonstrate the possibility of the integration of various passive components and MMICs in the millimeter-wave range. To reduce the size of the hybrid ring coupler, we used multiple open stubs on the inside of the ring structure. The chip size of the reduced hybrid ring coupler with multiple open stubs was decreased by 62% compared with the area of the hybrid ring coupler without open stubs. Performance in terms of the loss, isolation, and phase difference characteristics exhibited no significant change after the use of the multiple open stubs on the inside of the ring structure. The reduced hybrid ring coupler showed excellent coupling loss of $3.87{\pm}0.33dB$ and transmission loss of $3.77{\pm}0.72dB$ in the measured frequency range of 90-100 GHz. The isolation and reflection were -48 dB and -32 dB at 94 GHz, respectively. The phase differences between two output ports were $180^{\circ}{\pm}1^{\circ}$ at 94 GHz.

• Journal of Digital Contents Society
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• v.8 no.4
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• pp.459-465
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• 2007

In this paper, we implemented a ray-tracing simulator with a ray-launching technique and generated the propagation path of each ray in a multiple-wall indoor environment. In this simulator, we adopted two dimension ray-tracing techniques considering the reflection and penetration were dominant propagation factor in the indoor channel. From the result, we verified that this ray-tracing simulator shows the similar path pattern and delay distribution with the experiment results of the previous research. Especially, impulse responses of the ray were corresponding to reference result in non-line of sight of multiple-wall indoor environment. Furthermore, we confirmed that channel profiles having respectively different departure angle 1 degree to 7 degree were similar between them.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.528-533
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• 2005

A mono-static high frequency acoustic target strength analysis scheme was developed for underwater targets, based on the far-field Kirchhoff approximation. Au adaptive triangular beam method and a concept of virtual surface were adopted for considering the effect of hidden surfaces and multiple reflections of an underwater target, respectively. A test of a simple target showed that the suggested hidden surface removal scheme is valid. Then some numerical analyses, for several underwater targets, were carried out; (1) for several simple underwater targets, like sphere, square plate, cylinder, trihedral corner reflector, and (2) for a generic submarine model, The former was exactly coincident with the theoretical results including beam patterns versus azimuth angles, and the latter suggested that multiple reflections have to be considered to estimate more accurate target strength of underwater targets.

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.55-62
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• 2023

In this paper, we present a method that utilizes geometry-based sound generation techniques to efficiently handle multiple sound sources, wind turbulence, and temperature-dependent interactions. Recently, a method based on reduced raytracing has been proposed to update the sound position and efficiently calculate sound propagation and diffraction without recursive reflection/refraction of many rays, but this approach only considers the propagation characteristics of sound and does not consider the interaction of multiple sound sources, wind currents, and temperature. These limitations make it difficult to create sound scenes in a variety of virtual environments because they only generate static sounds. In this paper, we propose a method for efficiently constructing a sound map in a situation where multiple sounds are placed, and a method for efficiently controlling the movement of an agent through it. In addition, we propose a method for controlling sound propagation by considering wind currents and temperature. The method proposed in this paper can be utilized in various fields such as metaverse environment design and crowd simulation, as well as games that can improve content immersion based on sound.

• Journal of Gifted/Talented Education
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• v.19 no.1
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• pp.69-94
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• 2009

The purpose of this study was to develop and apply a Korean language education program based on multiple intelligences in a bid to foster the multiple intelligences, self-efficacy and achievement motivation of elementary schoolers in regular language arts class. It's basically meant to create the educational conditions for every child to exert his or her abilities. Two research questions were posed: 1. What should be the objectives, content and teaching-learning methods of a Korean language education program based on multiple intelligences? 2. What effect does a Korean education program based on multiple intelligences have on children's multiple intelligences, self-efficacy and achievement motivation? The subjects in this study were 58 Students in two different third-grade classes in M elementary school in the city of Daejeon. A Korean language education program based on multiple intelligences was implemented during a 4month period of time, and an inclusive approach of multiple intelligences and cooperative learning were applied. The major findings of the study were as follows: First, in order to develop a Korean education program based on multiple intelligences, the kinds of themes that could cover multiple intelligences in an inclusive way were selected in consideration of the learning objectives of the major units of a third-grade language arts textbook(second semester) of the 7th national elementary language arts curriculum. And then an inclusive Korean education program was prepared, which consisted of four stages: problem awareness, problem-solving planning, problem solving, and reflection/application/development. Second, the Korean education program based on multiple intelligences had a positive effect on the children's multiple intelligences, self-efficacy and achievement motivation and suggested some of new directions for school education that typically stressed linguistic and logical-mathematical intelligences only.

• Korean Journal of Social Welfare
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• v.51
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• pp.183-210
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• 2002

The purpose of this study is to investigate correction-level associated with the social support perceived by juvenile delinquents. To accomplish these purposes, this study used sample of 546 juvenile delinquents who are in the process of the beginning stage in the police and prosecution. Social support and correction were assessed with an instrument designed for this study. Juvenile delinquents completed instruments assessing the following variables: (1) perceived social support scale, specially social support types(esteem support, emotional support, informational support) and social support providers (parents, relatives, friends, teachers, community) (2) correction scale, specially social stigma, social deprivation, self reflection, legal consciousness, self concept. The resulting scale of the instrument had good internal reliability(Cronbach's alpha=. ) and was scored so that high scores indicated a willingness to access. To examine this purpose, One way ANOVA, multiple regression analysis were conducted. And the results are as follows: The relationship ratings of the correction factors were positively associated with their rating of the type of social support. Informational support was positively associated with self reflection and esteem support was positively associated with self concept, legal consciousness, self reflection and emotional support were positively associated with esteem. The type of support according to support providers was significant, explaining 25% of the variance in self concept scores. The significant predictor was esteem support from friends and emotional support from a community. The type of support according to support providers was significant, explaining 20% of the variance in legal consciousness scores. The significant predictor was informational support from teachers and esteem support from a community. The type of support according to support providers was significant, explaining 21% of the variance in self reflection scores. The significant predictor was esteem support and emotional one from relatives.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.135-151
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• 2012

Traditionally in IS studies, the relationship between construct and its measurement items tends to be assumed to be reflective, meaning that the measurements are a reflection of the construct. In reality, however, the nature of the construct can be often formative, which means that its measurement items describe and define the construct rather than vice versa. The purpose of this study was to investigate theoretical and empirically-analysed differences between formative construct and reflective construct through comprehensive interdisciplinary literature review. And then on the basis of these differences, we intended to derive the rule of specifying whether the construct is formative or reflective and propose the methodology of testing the validity(content validity, construct validity, internal consistency and external construct) of formative construct and its measurements, differentiated from that in the case of reflective construct. Also, we suggested the concrete statistical testing methods such as VTT(Vanishing Tetrad Test), MIMIC(Multiple Indicators and Multiple Causes) test and multi-collinearity test. In order to examine the applicability of this methodology to developing the constructs for performance evaluation of IS(Information Systems), we tried to identify its attribute(formative or reflective) and test the validity for the construct arbitrarily chosen among them which had been derived in our previous IS performance evaluation study by using this methodology. The result of the examination was that the methodology proposed in this study was significantly valid and effective in the area of IS performance evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.291-297
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• 1997

A 2.5 Gbp$\times$8 channel WDM signal was transmitted using read-deployed 123 km optical cable around Daejon area. An error free transmission was achieved with $10^{-10}$ criterion, but the receiver sensitivity varied depending on channel, and some channel showed BER floor. The reans was forud to be in reflection points, and the effects of multiple reflections on the ultra high bit transmission was found to be inreflection points, and the effects of multiple reflections on the ultra high bit transmission was analyzed in this paper.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.663-671
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• 2014

LED lamp arrangement is a critical issue in indoor visible light communication (VLC) system. In this paper, we analyze the illumination distribution under the arrangement of $2{\times}3$ and propose a method to find the optimal lamp arrangement. The method, based on the MIMO (Multiple Input/Multiple Output) system model and taking the first order reflection into consideration, enables accurate analysis of the arrangement of the LED lamps for any room. The studies show that under the optimal arrangement the uniformity of illumination is improved from 0.55 to 0.86, which guarantees that users can get almost equal lighting effects, no matter where they locate themselves. At the same time, the RMS delay spread distribution which is used to evaluate the inter-signal-interference (ISI) is analyzed, and the simulation results indicate that the optimal arrangement also can improve the communication quality by reducing the fluctuation of the RMS delay spread.