• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.7-10
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• 2003

This paper proposes the multiple objects focusing algorithm. Given multiple objects at different distances from a camera, we assume that one object is well-focused and the others are out-of-focused. The proposed auto-focusing algorithm is summarized as follows: (i) detects edges from an input image, (ⅱ) estimates the radius of PSF (Point Spread Function) across the edge, (ⅲ) gather edge points having same radius of PSF, (ⅳ) segments the image into regions with the same radius of PSF, and (ⅴ) restores the each segmented region using the corresponding PSF.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.537-540
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• 2005

Shaped Sound Focusing is defined as the generation of acoustically bright zone with a certain shape in space using multiple sources. The acoustically bright zone is a spatially focused region with relatively high acoustic potential energy level. In view of the energy transfer, acoustic focusing using multiple sources is essential because acoustic energy is very small to use other type of energy. It can be done by taking optimization techniques which can be acoustic brigtness control and acoustic contrast control. But it has not been frequently concerned about several cases, so the case of hollow cylinder shaped sound focusing is adapted and there wi11 be arguments about available control variables and spatially controllable region in this case.

• 한국음향학회지
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• 제25권5호
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• pp.239-245
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• 2006

시계열반전처리는 시간과 공간영역 동시에 집속을 수행할 수 있는 효과적인 방법으로 증명되어 왔으며, 시간영역에서의 집속 특성은 수중음향통신에서 광범위하게 이용되고 있다. 최근에는 해양도파관에서 동시 다중 집속이 적응 시계열 반전처리에 의해 구현되었다. 본 연구에서 적응 시계열반전처리에 의한 동시 다중 집속은 다중 수신을 위한 수중음향 통신 알고리즘으로 확장되며, 개발된 알고리즘은 수치실험과 실 데이터를 통해 다중 수신 위치에 동시에 자기등화가 가능함을 보였다.

• 대한치과의료관리학회지
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• 제10권1호
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• pp.76-83
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• 2022

This study was undertaken to confirm the relationship between the manner of focus and job performance of clinical dental hygienists. A survey was conducted, and the results of the survey were analyzed using multiple regression analysis. As a result, in the correlation between job performance ability and focusing manner and appreciation of the experience process, which are sub-factors of job performance ability and focusing manner, r=.161 (p<0.1) and appropriate distance r=.229 (p<0.1) indicated a positive (+) correlation. Multiple regression analysis revealed that the factors that have the greatest influence on job performance are type of workplace (β=-0.381), focusing attitude (β=0.166), marital status (β=-0.156), and age (β=0.152). Therefore, by confirming the relationship between focusing and job performance ability, we intend to provide the basic data necessary to prepare measures to improve dental hospital management and job performance.

• 한국정보시스템학회지:정보시스템연구
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• 제27권4호
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• pp.229-249
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• 2018

Purpose The purpose of this paper is to conduct exploratory comparative research on the determinants of successful crowdfunding projects, focusing on multiple crowdfunding platforms in Korea, U.S., and Japan. Design/methodology/approach This study collected data from three representative crowdfunding platforms: Wadiz (Korea), Kickstarter (U.S.), and Readyfor (Japan). Based on 1,906 crowdfunding projects from Wadiz, 3,864 projects from Kickstarter, and 3,060 projects from Readyfor, multiple regression models were applied. Findings Focusing on the crowdfunding projects which have overly achieved goal amount, the analysis results show that the number of comments, the number of Facebook likes and the number of backers have an positive impact on the performance of crowdfunding projects, while target amount has a negative impact. Comparatively, word counts of project description have an impact on funding performance in U.S. and Japan, while the number of images in project description affects funding performance in Korea and U.S. Meanwhile, video clips in project description has little impact on crowdfunding performance in all of the three funding platforms.

• The Journal of the Acoustical Society of Korea
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• 제27권3E호
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• pp.104-111
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• 2008

Recently, a method for robust time reversal focusing has been introduced to extend the period of stable focusing in time-dependent ocean environments [S. Kim et al., J. Acoust. Soc. Am. 114, 145-157, (2003)]. In this study, concept of focal-size broadening based on waveguide invariant theory in an ocean time reversal acoustics is described. It is achieved by imposing the multiple location constraints. The signal vector used in multiple location constraints are found from the theory on waveguide invariant for frequency band corresponding the extended focal range. The broadening of foci in an ocean waveguide can play an important role in the application of time reversal processing, particularly to the underwater acoustic communication with moving vehicles. The proposed method is demonstrated in the context of the underwater acoustic communication from the transmit/receive array (TRA) to a slowly moving vehicle.

• 비파괴검사학회지
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• 제29권3호
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• pp.242-247
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• 2009

The ability of time reversal techniques to focus ultrasonic beams on the source location is important in many aspects of ultrasonic nondestructive evaluation. In this paper, we investigate the time reversal beam focusing of ultrasonic array sensors on a defect in layered media. Numerical modeling is performed using the commercially available software which employs a time domain finite difference method. Two different time reversal approaches are considered - the through transmission and the pulse-echo. Linear array sensors composed of N elements of line sources are used for signal reception/excitation, time reversal, and reemission in time reversal processes associated with the scattering source of a side-drilled hole located in the second layer of two layer structure. The simulation results demonstrate the time reversal focusing even with multiple reflections from the interface of layered structure. We examine the focusing resolution that is related to the propagation distance, the size of array sensor and the wavelength.

• 한국음향학회지
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• 제43권2호
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• pp.184-199
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• 2024

잔여의 채널 간 간섭은 일반적인 시역전 처리 기반의 동시 다중 집속에서의 주요 문제점으로 고려되어진다. 본 논문에서는, 다수의 음원이 존재하는 수중 도파관환경에서의 채널 간 간섭을 완화하기 위해 그람-슈미트 과정을 시역전 처리에 적용하였다. 해상 실험 데이터 기반 수치 시뮬레이션을 통해 여러 위치로의 널 형성 및 서로 다른 음원의 위치에서의 각기 다른 신호의 왜곡 없는 동시 다중 집속이 가능함을 능동 시역전 처리 관점에서 검증하였다. 또한, 적응 시역전 처리 방법에 비해 수신기 개수의 감소에 상대적으로 적은 영향을 받는 것을 확인하였다. 제안된 알고리즘을 통해 수동 다중 입·출력 수중 통신에서의 채널 간 간섭이 효율적으로 제거됨을 해상 실험 데이터를 통해 보였다.

• 임상간호연구
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• 제23권3호
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• pp.341-349
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• 2017

Purpose: Focusing manner is very powerful mind-body self-help and self-awareness competence. So focusing manner may affect nurses' emotional labor and nursing performance, but few are known about it to date. The purpose of this study was to identify the degree of focusing manner, emotional labor, nursing performance of clinical nurses, and the factors that affect nursing performance. Methods: In order to collect data, structured questionnaires were administered to 212 nurses who worked at 2 university hospitals located in D city. Data were analyzed by t-test, ANOVA, correlation and multiple regression using SPSS/WIN 20.0. Results: Nursing performance had positive relationship with focusing manner (r=.45, p<.001), and negative relationship with emotional labor (r=-.25, p<.001). And the most prediction factor influencing nursing performance was focusing manner (${\beta}=.41$, p<.001) and the other factors were age (${\beta}=.30$, p=.002), and emotional labor (${\beta}=.14$, p=.012). The total variance was 37.1% by those predictors (F=25.87, p<.001). Conclusion: Based on the results of this study, it is necessary to develop and educational program on focusing manner-oriented psychotherapy in order to improve the nursing performance. Also, the management system for controlling emotional labor needs to be set up for nurses in clinical settings.

• 비파괴검사학회지
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• 제28권6호
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• pp.531-537
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• 2008

One of the fundamental features of time reversal acoustic (TRA) techniques is the ability to focus the propagating ultrasonic beam to a specific point within the test material. Therefore, it is important to understand the focusing properties of a TR device in many applications including nondestructive testing. In this paper, we employ an analytical scheme for the analysis of TR beam focusing in a homogeneous medium. More specifically, a nonparaxial multi-Gaussian beam (NMGB) model is used to simulate the focusing behavior of array transducers composed of multiple rectangular elements. The NMGB model is found to generate accurate beam fields beyond the nonparaxial region. Two different simulation cases are considered here for the focal points specified on and off from the central axis of the array transducer. The simulation results show that the focal spot size increases with increasing focal length and focal angle. Furthermore, the maximum velocity amplitude does not always coincide with the specified focal point. Simulation results for the off-axis focusing cases do demonstrate the accurate steering capability of the TR focusing.