• Proceedings of the IEEK Conference
• /
• 2003.11a
• /
• pp.7-10
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.537-540
• /
• 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.

• The Journal of the Acoustical Society of Korea
• /
• v.25 no.5
• /
• pp.239-245
• /
• 2006

Time-reversal processing (TRP) has been shown as an effective way to focus in both time and space. The temporal focusing properties have been used extensively in underwater acoustics communications. Recently. adaptive time-reversal processing (ATRP) was applied to the simultaneous multiple focusing in an ocean waveguide. In this study. multiple focusing with ATRP is extended to the underwater acoustic communication algorithm for multiple receiving locations. The developed algorithm is applied to the underwater acoustic communication to show, via simulation and real data, that the simultaneous self-equalization at multiple receiving locations is achieved.

• Journal of Korean Academy of Dental Administration
• /
• v.10 no.1
• /
• pp.76-83
• /
• 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.

• The Journal of Information Systems
• /
• v.27 no.4
• /
• pp.229-249
• /
• 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
• /
• v.27 no.3E
• /
• pp.104-111
• /
• 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.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.3
• /
• pp.242-247
• /
• 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.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.2
• /
• pp.184-199
• /
• 2024

Residual crosstalk has been considered as a major drawback of conventional time-reversal processing in the case of simultaneous multiple focusing. In this paper, the Gram-Schmidt process is applied to time-reversal processing to mitigate crosstalk in ocean waveguides for multiple probe sources. Experimental data-based numerical simulations confirm that nulls can be placed at multiple locations, and it is shown that different signals can be simultaneously focused at different probe source locations, ensuring distortionless responses in terms of active time-reversal processing. This focusing property is also shown to be much less affected by a reduction in the number of receivers than the adaptive time-reversal mirror method. The proposed method is shown to be effective in eliminating crosstalk in passive multi-input multi-output communications using sea-going data.

• Journal of Korean Clinical Nursing Research
• /
• v.23 no.3
• /
• pp.341-349
• /
• 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.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.28 no.6
• /
• pp.531-537
• /
• 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.