• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.32-37
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• 2008

Satellite communication systems including the DVB-S2 (Digital Video Broadcasting - Satellite Version 2) system require operations under low signal-to-noise ratio (SNR) and large frequency offset values, and the initial frame synchronization process necessitates a robust correlation method. While a variety of conventional correlation structures exist for the initial synchronization, each method has different characteristics and performance in different channel environments. In this paper, we propose new correlation methods which exhibit enhanced performance in low SNR and large frequency offsets, and analyze their performance. The proposed methods use the magnitude sum and vector sum of extended differential correlation values, to maximize the correlation between the received signal and the synchronization sequence by using the spanned differential correlation result. The magnitude sum correlation method has better performance compared to conventional methods including the approximated ML (Maximum likelihood) method for SNR values below 4 dB with or without frequency offsets. The vector sum correlation method has improved performance over the magnitude sum method for channels with relatively small frequency offsets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1884-1891
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• 2012

In this paper, we design the sliding correlator SS transceiver which supports short message service. We also analyze the PN code acquisition circuit that is essential for spread spectrum receiver. Using Maxplus II tool provided by altera Co., Ltd, we have designed PN code generator, and sliding correlator for PN code acquisition. Then, they have been made into FPGA by way of EPM7064SLC44-10 - a chip of Altera Co., Ltd. Additionally, we have designed delay clock circuit which is faster than the clock of Tx PN clock, designed switching circuit to control the clock rate and data demodulation circuit. The performance of the transceiver is evaluated from the experimental results. Especially, the performance of PN code acquisition accomplished by sliding correlator which is very important to evaluate spread spectrum receiver is evaluated with the comparison of the lock states.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.53-66
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• 2012

The purpose of the study was to examine the relationships among gender, shopping motivations, flow experience, and purchases using structural equation modeling. Shopping motives were included in the study: self-refreshment, idea seeking, social interaction, product acquisition, and value seeking. Data from 452 male and female respondents were employed to test the model. Empirical findings supported that the proposed model was a good fit to data. Gender played an influential role in shopping motives. All motives except for product acquisition motive significantly influenced flow experience. Flow experiences enhance the purchasing. This study contributed the literature by providing a conceptual foundation of how gender and shopping motivation influence flow experience.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.369-378
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• 2017

This study is devoted to investigating participation motivations of billiard players who join games through open-ended questionnaires, and identify the difference of participation motivations in the game according to age and experience. Thus, 696 original data on participation motivations was obtained from 267 billiard players in Gyeonggi-do based on open-ended questionnaires. Results from inductive analysis are as follows. First, their participation motivations included 10 general sectors such as interests, objective achievement motive, competition, interpersonal relationship, mental health, job, gambling, sport competence, suggestion by others, and university admission. Second, enjoyment showed the highest percents among participation motivations according to participants' age. Third, interest showed the highest percents among participation motivations in less than five years of their experiences. Objective achievement motive was the highest portion for more than five years. These outcomes will be used as a basic data to understand the relationship of billiard players who participate in the game and further create better billiard game culture.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.149-153
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• 2003

AC 부하를 갖는 동기전동기에 있어서, 동기전동기의 속도리플을 저감시키기 위한 문제를 풀기위해 3가지 제어기법에 대해 비교를 한 후 가장 강인한 제어기법에 대해 분석하였다. AC 부하를 갖는 특별한 제어 대상으로 엑스선 전산화 단층촬영 장치(CT)용 겐트리를 선정하였으며 시스템이 갖는 특별한 구조에 의해 이러한 시스템 특성을 갖는다. 동기전동기의 출력 축에 링(Fing) 모양의 원판 프레임을 갖으며, 이 원판 표면에 무게가 서로 다른 여러 장치(X_선 튜브, X-선 검출기, 고압발생장치, DAS 장치, 온도조절장치 등)를 부착하여 영상 획득 시스템의 회전부를 구축하기 때문이다. 이러한 시스템에서는 무게 평형을 갖지 못하는 편심 무게가 존재하게 되며 이로써 전동기 관점에서는 AC 부하처럼 인식되는 제어 조건으로 인식 될 수 있다. AC 부하를 갖는 동기전동기에 대해 일반적인 벡터제어 알고리즘으로 제어를 수행하면 정상상태에서도 속도 오차가 "0" 으로 줄어들지 않고 AC 형태의 오차 성분이 존재하며 편심 무게의 크기에 비례하여 진폭이 커지는 특성을 갖는다. 이러한 문제점을 해결하기 위하여 Sine파 보상전류를 갖는 속도제어기법, 펀심부하토크 관측기를 이용한 속도제어기법, 그리고 기준모델제어기법을 소개하였다. 각 방법에 대한 실험 결과로부터 편심무게의 변동과 편심 위치의 변동 조건에서 기준모델제어기법이 강인한 제어 특성과 리플저감 측면에서 가장 우수함을 검증하였다. 이로써 AC 부하 조건에서 고정도 속도 제어기가 요구되는 경우 좋은 선택의 지침이 될 수 있다고 본다.

• Journal of the Korea Computer Graphics Society
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• v.23 no.2
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• pp.41-47
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• 2017

In this paper, we present a method for data-driven correction of the noisy motion data captured from a low-end RGB-D camera such as the Kinect device. For this purpose, our key idea is to construct a synchronized motion database captured with Kinect and additional specialized motion capture device simultaneously, so that the database contains a set of erroneous poses from Kinect and their corresponding correct poses from the mocap device together. In runtime, given motion captured data from Kinect, we search the similar K candidate Kinect poses from the database, and synthesize a new motion only by using their corresponding poses from the mocap device. We present how to build such motion database effectively, and provide a method for querying and searching a desired motion from the database. We also adapt the laze learning framework to synthesize the corrected poses from the querying results.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.3-9
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• 2015

In this paper, we propose an initial timing and frequency synchronization scheme for low probability detection (LPD) systems with cyclic code shift keying (CCSK). The performance of the LPD system with CCSK highly depend on initial timing and frequency offset. On the other hand, the operating SNR (Signal-to-Noise Ratio) of LPD systems is usually very low. Hence, to guarantee a reliable performance of the LPD system, it is crucial to develop suitable initial synchronization algorithms. In this paper, we propose an initial timing and frequency synchronization scheme suitable for CCSK based LPD system using a repeated preamble pattern.

• Cartoon and Animation Studies
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• s.38
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• pp.259-286
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• 2015

This study investigates the effect of the motivation to use webtoon and the convenience of use(the character of the webtoon service) on the interactivity, and then examines how the interactivity affect the webtoon user's satisfaction and willingness to pay. Using factor analysis, this study found two motivations to use webtoon including 'information acquisition', 'entertainment and easiness of access'. These motivations have an influence on the interaction of the content and Webtoon's user and of Webtoon's users. The motivation of the entertainment and easiness of access is more influential to user's interactivity. The convenience of use is divided two types that are the convenience of the searching information and service. The convenience of webtoon service has positive influence of two types of interaction. The last results find that webtoon user's satisfaction is influenced by gender, the convenience of the searching information and using service. The satisfaction of the female user is higher than man. The more convenience of use is, the more satisfaction of users will be. Willingness to pay is influenced by age, the convenience of webtoon service, and the user's interactivity. The older users are, the more convenience of webtoon service is, and the more the user's interactivity, the higher willing to pay will get. The implications of the findings are discussed in terms of the way to change the profit structure of webtoon service and suggest to increase the interactivity in webtoon service.

• International Area Studies Review
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• v.22 no.1
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• pp.101-121
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• 2018

This paper studies the influence of multinational R&D Labs' expansion motives on their business performance and the mediating effect of the level of control on this motive-performance relationship. Through an in-depth study of the relevant literature, the expansion motives can be divided into four general types. The first is called a market factor in the sense that the purpose of their expansion is to secure potential markets and customers in China. The second is called a resource factor; their purpose is to obtain excellent technology and a workforce from the country. The third is called an institution factor. An example is the case of R&D Labs advancing into China to make the best of its institutional advantages such as the government's benefits, related policies, and incentive articles. The last is called a strategic factor and indicates the case where they go into China for the purpose of competing in the market, considering it as a major strategic place. The companies' control level on their R&D Labs was measured for each item. According to the empirical analysis on the relevance of their control level and expansion motives, it turns out that giving a free hand to the Labs which pursue market, institutional, and strategic factors is more desirable than highly controlling them. This is because they should be familiar with the local business environment in consideration of those companies' objectives. In light of the mediating effects of the control level on expansion motives and business performance, the R&D Labs pursuing resource factors seem to need their headquarters' control to make the best use of the high-end technology obtained in the country. The companies pursuing strategic factors seem to hold a dominant position and perform more competitively when their headquarters control the Labs more tightly.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.843-851
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• 2006

본 논문에서는 음성에 따른 얼굴 애니메이션을 사실적으로 표현하기 위한 조음기관(혀, 성대 등)의 움직임을 시각화하는 방법을 제시한다. 이를 위해서, 음성에 따른 얼굴 애니메이션을 위한 말뭉치(Corpus)를 생성하고, 생성된 말뭉치에 대해서 음소 단위의 분석(Phoneme alignment) 처리를 한 후, 각 음소에 따른 조음기관의 움직임을 생성한다. 본 논문에서는 조음기관의 움직임 생성을 위해서 얼굴 애니메이션 처리에서 널리 사용되고 있는 기저 모델 기반 형태 혼합 보간 기법(Blend shape Interpolation)을 사용하였다. 그리고 이를 통하여 프레임/키프레임 기반 움직임 생성 사용자 인터페이스를 구축하였다. 구축된 인터페이스를 통해 언어치료사가 직접 각 음소 별 조음기관의 정확한 모션 데이터를 생성토록 한다. 획득된 모션 데이터를 기반으로 각 음소 별 조음기관의 3차원 기본 기저를 모델링하고, 새롭게 입력된 음소 시퀀스(phoneme sequence)에 대해서 동기화된 3차원 조음기관의 움직임을 생성한다. 이를 통해 자연스러운 3차원 얼굴 애니메이션에 적용하여 얼굴과 동기화된 조음 기관의 움직임을 만들어 낼 수 있다.