• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.52-57
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• 2001

The passive ranging estimation techniques using a focused beamformer have been studied under the water. It is well known that the passive ranging estimation method using a focused beamformer is excellently evaluated. Among these, the passive ranging sonar is known to have a good performance under low signal-to-noise. ratio. However, its performance is degraded in multi-source environments. In this paper, we proposed the technique using dual focused beamformers to estimate the range. And when the sampling frequency is low, it is very difficult to steer the focused beam to the desired direction, as a result of this, the low performance occurs because of a distorted beam pattern. In this paper, we study the effect of sampling rate on passive ranging by using focused beamformer. And we verified the performance of the proposed method via computer simulation.

• The Journal of the Acoustical Society of Korea
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• v.36 no.2
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• pp.100-107
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• 2017

The focused MVDR (Minimum Variance Distortionless Response) can be applied for source localization in near field. However, if the number of sensors are increased, it requires a large amount of calculation to obtain the inverse of the covariance matrix. In this paper we propose a focused MVDR method using that beam space is formed from output of far field beamformer at the subarray. The performances of the proposed method was evaluated by simulation. As a result of simulation, the proposed method has the higher spatial resolution performance then the conventional delay-and-sum beamformer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1117-1123
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• 2009

Head fixed type multi-focus display system using Galvano-scanner and DMD(Digital Micro-mirror Device), which is able to perfectly accommodate, can solve eye fatigue due to conflict between convergence eye movement and accommodation action in stereoscopic display. This system is able to accommodate through making convergence point about each view point and offering it in front of observer's pupil by using laser scanning method. In this paper, we analyzed laser scanning method of this multi-focus display system. And multi-focus display system based on this analysis was made, which showed that focus adjustment was possible through video camera. As a result, formation principle of view point of multi-focus system by laser scanning method was verified.

• Informatization Policy
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• v.19 no.2
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• pp.3-20
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• 2012

This study examines the trend and issues of sociological studies of social network service(SNS). For this purpose, the studies were classified into three types. The first type of study concerns spatial characteristics of SNS. It deals with the impact of such SNS usage on individual attitudes and behaviors. The second type of the study focuses on the formation process of interrelationship among users. It is based on sociological concepts such as trust and social capital. The last type of study emphasizes the impact of SNS on society. The study includes the issues of social movement and political participation. In the future study of SNS, more diverse sociological subjects, such as social integration, exclusion, public welfare, and affective support need to be dealt with.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.289-292
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• 2002

국어에서 wh-단어가 포함된 의문사 의문문과 부정사 의문문은 통사적으로 같은 구조를 가지지만 의미적으로는 중의 관계에 있다. 그러나 두 의문문은 문장으로 발화될 때 음성적으로 서로 다른 여러 가지 운율 특징의 차이를 보여줌으로써, 발화 차원에서는 더 이상 중의 관계를 유지하지 않는다. 본고에서는 이러한 중의성의 해소는 두 의문문의 초점이 달리 실현되기 때문이라고 본다. 기존의 연구에서는 두 가지 의문문의 억양 연구를 초점의 작용 범위와 문말 억양의 차이, 강세구 형성의 유형을 중심으로 고찰하였다 .그리고 의문사와 부정사의 의미는, 이에 후행하는 서술어와 형성하는 강세구 유형에서 우선적으로 그 의미가 구분될 수 있다고 보았다. 그러나, 본고에서는 국어의 wh-단어가 초점으로서 작용하는 운율적 돋들림을 좀더 다양한 환경에서 실험하였다. 그리고 의문사${\cdot}$부정사와 후행하는 언어단위의 강세구 형성(accentual phrasing) 유형, 의문사${\cdot}$부정사 의문문 전체 문장 억양의 실현 양상, wh-단어 자체의 음의 높낮이(pitch contour) 실현 유형, 문말 억양(boundary tone)에서 음의 높낮이를 대상으로 분석하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.243-246
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• 1998

집속음장의 고조파성분을 이용한 초음파영상의 특성을 해석하기 위해 집속된 가우스 음원에 직선 edge를 초점면 및 초점면의 전, 후방에 삽입하여 edge의 후방에서 생성되는 음장을 조사하였다. 계산에서는 그린함수의 간단화를 위해 Fresnel근사를 이용하였고, 실험에서는 성형전극을 형성시킨 1.9MHz 요면진동자에 의한 가우스분포의 음장을 갖는 초음파빔에 수직하게 edge를 삽입시켰다. 음장의 이론해석 및 실험결과, 초점면의 제2고조파의 빔형상을 제외하고는 계산치와 실험치가 잘 일치하고 있으며, 제2고조파의 공간 분해능이 기본파에 비해 높음을 알았다.

• Annual Conference on Human and Language Technology
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• 2007.10a
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• pp.54-61
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• 2007

양화문 안의 강 양화사와 약 양화사가 전제적/비전제적 해석과 관련된 영향권 다툼의 과정에서도 약 양화사가 주어이든 목적어이든지 표면 형태에서 VP로부터 멀리 떨어져 있는 경우에는 전제적 해석만을 받게 되어 양화문에 중의성이 발생하지 않는다. 그런데 타동사의 목적어나 비대격 주어 등의 약 양화사가 초점에 민감한 경우에 비전제적 해석이 가능하게 되어 중의적인 문장이 될 수 있다고 본다. 표면구조상 VP 밖에 위치한 약 양화사라도 초점화 되면, 초점투사를 통하여 논리 형태에서 형성된 초점의 영향권(초점 구문) 안에 들어있게 되며, 이때의 초점이 가지는 영향권은 핵 영향권과 일치한다. 즉, 초점은 안에 있는 약 양화사가 핵 영향권 안에서 비전제적으로 해석되도록 하는 동력으로 작용한다고 볼 수 있다.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.170-175
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• 2009

Shock focusing is related with explosive release of shock wave energy on a narrow spot in a short duration of time triggering a spontaneous high pressure near the focal point. It is well known that reflection of planar incident shock wave from the metallic concave mirror such as ellipsoidal, paraboloidal or hemispherical cavities will focus on a focal point. We intend to improve the computational results using a wave propagation algorithm and to resolve the mushroom-like structure. For computation of the concave cavity flow, it is not easy to use a single-block mesh because of the many singular points in geometry and coordinates. We have employed a uniform Cartesian-grid method for the wave propagation algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.81-89
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• 2017

Autofocus(AF) Method is essential to overcome the performance degradation due to motion measurement errors under airborne SAR environment. In this paper, back-projection algorithm(BPA) is applied to SAR raw data acquired under the squinted mode, and preprocessing algorithm of AF for BPA is investigated. To apply AF to SAR image effectively, image backplane rotation method and doppler location alignment function for BPA are proposed. The proposed method is applied to SAR raw data acquired in a flight test and shows excellent performance improvement in real data.

• Asia Marketing Journal
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• v.10 no.4
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• pp.1-33
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• 2009

This research investigates the effect of brand-self identification on brand attachment and brand commitment focusing on luxury brand. Another purpose of this study is to examine how the relationships among brand identification, brand attachment and brand committment are moderated by consumers' regulatory focus. Structural Equation Modeling using 214 questionnaires was conducted to test hypothesized model. The results reveal that perceived luxury brand personality including excitement, competence, and sophistication influences brand-self identification positively, which in turn has a signifiant positive effect on the brand attachment. It is also found that consumers' emotional attachment to luxury brands has a positive influence on the luxury brand commitment while the effect of the brand-self identification on the brand commitment is not signifiant. This finding strongly supports that brand attachment and brand commitment are distinct construct, which confirms the results of the previous studies. In addition, the results show that consumers-luxury brands relationships are moderated by consumers' regulatory focus. This finding explains that prevention-focused individuals who have interdependent self-view respond to the loss caused by relationship break more sensitively compared to the promotion-focused consumers. Finally, based on the findings of this study, theoretical contribution and managerial implications are discussed.