• Title/Summary/Keyword: focal point

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Simultaneous Multiple Transmit Focusing Method with Orthogonal Chirp Signal for Ultrasound Imaging System (초음파 영상 장치에서 직교 쳐프 신호를 이용한 동시 다중 송신집속 기법)

  • 정영관;송태경
    • Journal of Biomedical Engineering Research
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    • v.23 no.1
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    • pp.49-60
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    • 2002
  • Receive dynamic focusing with an array transducer can provide near optimum resolution only in the vicinity of transmit focal depth. A customary method to increase the depth of field is to combine several beams with different focal depths, with an accompanying decrease in the frame rate. In this Paper. we Present a simultaneous multiple transmit focusing method in which chirp signals focused at different depths are transmitted at the same time. These chirp signals are mutually orthogonal in a sense that the autocorrelation function of each signal has a narrow mainlobe width and low sidelobe levels. and the crossorelation function of any Pair of the signals has values smaller than the sidelobe levels of each autocorrelation function. This means that each chirp signal can be separated from the combined received signals and compressed into a short pulse. which is then individually focused on a separate receive beamformer. Next. the individually focused beams are combined to form a frame of image. Theoretically, any two chirp signals defined over two nonoverlapped frequency bands are mutually orthogonal In the present work. however, a tractional overlap of adjacent frequency bands is permitted to design more chirp signals within a given transducer bandwidth. The elevation of the rosscorrelation values due to the frequency overlap could be reduced by alternating the direction of frequency sweep of the adjacent chirp signals We also observe that the Proposed method provides better images when the low frequency chirp is focused at a near Point and the high frequency chirp at a far point along the depth. better lateral resolution is obtained at the far field with reasonable SNR due to the SNR gain in Pulse compression Imaging .

Structuring of Integrated Design System Based on Emotion Process Model for Successful Brand Image Building (성공적 브랜드 이미지 구축을 위한 감성 처리 모형 기반의 통합 디자인 체계 구성)

  • Kim, Hyun
    • Science of Emotion and Sensibility
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    • v.11 no.1
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    • pp.57-68
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    • 2008
  • With the shift of consumer’s spending behaviors further into emotionally-driven purchases, the role of brand is becoming even more important, which in turn, expands design’s role in the brand image strategy. The contact point between the consumers and the brand is the primary channel for building strong brand image through experience. Therefore, it is critical to comprehensively plan and manage the consumer contact point for any brand. Given the changing market conditions, the objective of this study is to define and structure an integrated design development and management system for building successful brand image. In order to do so, the research analyzed the characters of brand image, the conditions for consumer experience and the roles of emotion. The analysis into the correlation between images and emotion process model yields three natures of an image. The image 1) is based on empirical decisions, 2) expresses and conveys emotional aspects and 3) builds mental values through a sense of sympathy. Through case studies of successful designs that meet all three characteristics, the roles of a brand icon in building strong brand image and the needs for integrated design approach for implementation are defined. The methods for integrated design include 1) providing a focal point through brand image positioning, 2) utilizing visual themes based on brand image plot, 3) building a Total Identity Program to holistically manage brand images and 4) developing brand icons for brand image reinforcement.

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Stereo cameras calibration bases on Epipolar Rectification and its Application

  • Chaewieang, Pipat;Thepmanee, Teerawat;Kummool, Sart;Jaruvanawat, Anuchit;Sirisantisamrid, Kaset
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.246-249
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    • 2003
  • The constraints necessary guarantee using the comparison of these extrinsic parameters, which each Rotation matrix and Translation Vector must be equal to the either, except the X-axis Translation Vector. Thus, we can not yet calculate the 3D-range measurement in the end of camera calibration. To minimize this disadvantage, the Epipolar Rectification has been proposed in the literature. This paper aims to present the development of Epipolar Rectification to calibrate Stereo cameras. The required computation of the transformation mapping between points in 3D-space is based on calculating the image point that appears on new image plane by using calibrated parameters. This computation is assumed from the rotating the old ones around their optical center until focal planes becomes coplanar, thereby containing the baseline, and the Z-axis of both camera coordinate to be parallel together. The optical center positions of the new extrinsic parameters are the same as the old camera, whereas the new orientation differs from the old ones by the suitable rotations. The intrinsic parameters are the same for both cameras. So that, after completed calibration process, immediately can calculate the 3D-range measurement. And the rectification determines a transformation of each image plane such that pairs of conjugate Epipolar lines become collinear and parallel to one of the image axis. From the experimental results verify the proposed technique are agreed with the expected specifications.

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Thermal distribution change in polyvinyl alcohol gel caused by focused ultrasound (폴리비닐알코올 젤의 집속초음파에 의한 온도분포 변화)

  • Kim, Jungsoon;Kim, Moojoon
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.6
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    • pp.576-584
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    • 2020
  • In order to obtain basic information for using polyvinyl alcohol (PVA) gel as a tissue mimicking phantom for temperature visualization, the temperature change characteristics due to the focused ultrasound were examined for different concentration of PVA. To obtain the basic acoustic characteristics, the speed of sound, the attenuation coefficient, and the density depending on the PVA concentration were measured, and the thermodynamic characteristics, such as thermal conductivity and heat capacity, were measured. The range of temperature rising in the vicinity of the focal point due to the focused ultrasound was observed using a thermochromic film that changes color at 30 degree or more, and the discolored area was obtained by image processing of the recorded image. As the concentration of PVA increases in the given range of 2 wt% ~ 16 wt%, the area that rises above 30 degree inside the gel increases linearly. It is confirmed that the discolored area increases as the power applied to the focused ultrasonic transducer increases. These results showed good agreement with the simulation results using the finite element method.

Calibration Method of Plenoptic Camera using CCD Camera Model (CCD 카메라 모델을 이용한 플렌옵틱 카메라의 캘리브레이션 방법)

  • Kim, Song-Ran;Jeong, Min-Chang;Kang, Hyun-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.2
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    • pp.261-269
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    • 2018
  • This paper presents a convenient method to estimate the internal parameters of plenoptic camera using CCD(charge-coupled device) camera model. The images used for plenoptic camera calibration generally use the checkerboard pattern used in CCD camera calibration. Based on the CCD camera model, the determinant of the plenoptic camera model can be derived through the relationship with the plenoptic camera model. We formulate four equations that express the focal length, the principal point, the baseline, and distance between the virtual camera and the object. By performing a nonlinear optimization technique, we solve the equations to estimate the parameters. We compare the estimation results with the actual parameters and evaluate the reprojection error. Experimental results show that the MSE(mean square error) is 0.309 and estimation values are very close to actual values.

Modern Values of Character Education Observed through Sohak in Convergence Era (융복합시대에 『소학』을 통해 본 인성교육의 현대적 가치)

  • Cha, Hyeon-ju
    • Journal of Digital Convergence
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    • v.14 no.10
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    • pp.553-561
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    • 2016
  • This research focuses on the modern social phenomenon on child education which still, heavily focuses on knowledge transfer where in the past, traditional society emphasized its focal point on character education. At this, character education plans from various angles have been performed. However, the timely request for character education is becoming more desperate in demand. Therefore, the research has contemplated on Sohak, which was the foundation of character education in Korean traditional education, and recognized necessity to review its modern values as the convergence era has approached our society. Modernization of Sohak's teachings to approach modern issue of character education in our society will hold significant value because of its creative inheritance of psychological values and culture to children from the traditional society.

Analysis of Constructional Characteristics of Art-walls in Apartment Houses (공동주택 실내공간 아트월의 구성특성 분석)

  • Park, Young-Soon;Kim, Eun-Jeong;Kim, Seong-Ah;Im, Joon-Bin;Yim, Sun-Hee
    • Korean Institute of Interior Design Journal
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    • v.19 no.2
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    • pp.144-154
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    • 2010
  • This study aimed at analyzing physical characteristics of art-walls which is a focal point in contemporary interiors of the apartment houses. The factors for the analysis were types of apartments, positions, widths, compositions of elevation, and materials of art-walls. 89 art-walls were selected for the analysis ranging from $76m^2$ to $187m^2$. The result shows that wood was mostly applied to art-walls in small types of apartment in combination with other materials, and the composition of elevation was asymmetric. If the width of art-walls became smaller, the elevation was dominantly designed with symmetrical grid using tiles. Tiles turned out to be the general material for the single-applied material. However, if more than two materials were applied to art-walls, wood was chosen as the main material. Regardless of the types of apartment, big-sized art-walls were usually designed in the living room, and two different types of materials were applied to the walls. It reveals that art-walls of apartment houses have been planned and designed with focuses on the living room in the housing space. To make a modular panel for the art-walls, 400mm and 800mm sizes were both suggested, 400mm for the smaller composition, and 800mm for the larger composition of the art-walls. A Wall image is becoming more essential to the living space these days, because it can be both decorative and also supportive to residents' various individualities. Therefore, it is expected that further researches on art-walls are continuously performed, and also various designs of art-walls based on the modular system are developed in the near future.

A Distortion Correction Method of Wide-Angle Camera Images through the Estimation and Validation of a Camera Model (카메라 모델의 추정과 검증을 통한 광각 카메라 영상의 왜곡 보정 방법)

  • Kim, Kyeong-Im;Han, Soon-Hee;Park, Jeong-Seon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.12
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    • pp.1923-1932
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    • 2013
  • In order to solve the problem of severely distorted images from a wide-angle camera, we propose a calibration method which corrects a radial distortion in wide-angle images by estimation and validation of camera model. First, we estimate a camera model consisting of intrinsic and extrinsic parameters from calibration patterns, where intrinsic parameters are the focal length, the principal point and so on, and extrinsic parameters are the relative position and orientation of calibration pattern from a camera. Next we validate the estimated camera model by re-extracting corner points by inversing the model to images. Finally we correct the distortion of the image using the validated camera model. We confirm that the proposed method can correct the distortion more than 80% by the calibration experiments using the lattice shaped pattern images captured from a general web camera and a wide-angle camera.

A meta-analysis survey of the research on domestic e-banking (국내 전자금융 연구동향에 대한 메타분석)

  • Yoo, Soon-Duck;Choi, Kwang-Don
    • Journal of Digital Convergence
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    • v.13 no.4
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    • pp.175-189
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    • 2015
  • As issues of Fintech(Financial technology) emerge, research on electronic banking is growing and garnering much attention in the market. This study analyzed 184 studies on e-banking over 15 years, from 2000 to 2014. Using meta-analysis, the paper draws attentions to the trends in domestic electronic banking studies. Interest peaked in 2008, when 28 papers were published and 35 theses in Information Security and Cryptology were announced. This research focus emphasizes the impact of e-banking services, technology and infrastructure, and laws and regulations on society. Electronic payment systems are a focal point of research on technology and infrastructure. Research on the e-finance market have influenced studies on the financial progress and other social issues. Benefits of this research include a better understanding of the trends in electronic banking studies and its influence on related fields, as well as help electronic banking-related policies and technology research.

A Study of Establishing Converged Service R&D Infrastructure (융합형 서비스R&D 인프라 구축방안 연구)

  • Oh, Taek Su;Kim, Suk Pil;Kim, Seong Dong
    • Journal of Information Technology Services
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    • v.13 no.4
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    • pp.341-357
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    • 2014
  • Service R&D that adds high value to existing products and service by scientification, IT convergence, intellectualization is a core business of creative economy. It is necessary to examine the service R&D revitalization plan by establishing service R&D hub researching the service R&D because a shortage of facility and infrastructure makes impossible to turn ideas into products (service). This research aims at establishing the implementation plan of service R&D hub that invigorates local service industries and contributes to carry out the plan. Service R&D hub is a focal point of service R&D activities which inter-connects service R&D activities distributed across ministries of central government and fields of studies, and which invigorates service R&D activities and enhances competitive power of service industries in Korea. It is necessary to establish main hub like Service Engineering Research Center in Japan and Fraunhofer IAO in Germany which take the lead in national service R&D activities, and make it build the solid foundation of service R&D activities in public sector and also create service innovation ecosystem. Considering the interdisciplinary characters of service R&D, it is essential to establish additional sub-hubs to meet a variety of demands of service R&D. It is also necessary to establish 'Living Lab', an open innovation system, which connects research institutions, universities, and corporates to make them target the specific fields of their own, and enhance open R&D and innovation in service industries.