• Title/Summary/Keyword: Wave focusing

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Generation of a plane-wave field by point focusing of acoustic potential energy on the radiation sphere in the wavenumber domain (파수 영역의 방사 구면에서 음향 에너지 집중을 통한 평면파 생성 방법)

  • Chang, Ji-Ho;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.820-823
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    • 2007
  • In the wavenumber domain, each point on a radiation sphere indicates a plane wave of the frequency corresponding to radius of the sphere and the position on the sphere shows propagating direction of the plane wave. This concept is extended from the research by Choi[1] where he focus acoustic potential energy at a point on a radiation sphere. Here we propose the method to focus the energy at a point on the radiation sphere, as a result, we can easily generate a plane wave which propagates to any direction that we want.

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WAVEs: A Novel and Promising Weapon in the Cancer Therapy Tool Box

  • Sakthivel, K.M.;Prabhu, V. Vinod;Guruvayoorappan, C.
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.1719-1722
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    • 2012
  • The Wiskott-Aldrich Syndrome Protein family Verprolin - homologous proteins (WAVEs), encoded by a metastasis promoter gene, play considerable roles in adhesion of immune cells, cell proliferation, migration and destruction of foreign agents by reactive oxygen species. These diverse functions have lead to the hypothesis that WAVE proteins have multi-functional roles in regulating cancer invasiveness, metastasis, development of tumor vasculature and angiogenesis. Differentials in expression of WAVE proteins are associated with a number of neoplasms include colorectal cancer, hepatocellular cancer, lung squamous cell carcinoma, human breast adenocarcinoma and prostate cancer. In this review we attempt to unify our knowledge regarding WAVE proteins, focusing on their potentials as diagnostic markers and molecular targets for cancer therapy.

A Study on the Popular Factors, Consumption Paths and Effects of Korean Wave Contents: Focused on the Indonesian Market (한류콘텐츠의 인기 요인, 소비 경로 및 효과에 관한 연구:인도네시아 시장을 중심으로)

  • Moon, Hyo-jin
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.2
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    • pp.201-206
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    • 2019
  • The study aims to explore ways to advance into the Indonesian market, focusing on hallyu contents such as Korean dramas, music and movies. To this end, we have empirically explored the reasons why local people in Indonesia like Korean wave contents, its consumption channels, its popularity factors for Korean wave contents and its effectiveness. According to the research, the reasons for the popularity of Korean wave contents were confirmed by the quality of the contents itself and the human appeal of the contents. And the consumption path was mainly through television, and the favorable impression of Korean wave contents was found to have a positive effect on the positive feeling toward Korea and the willingness to visit Korea.

Study Of Millimeter-Wave Passive Imaging Sensor Using the Horn Array Antenna (반사판을 이용한 밀리미터파 수동 이미징 시스템 연구)

  • Lim, Hyun-Jun;Chae, Yeon-Sik;Jung, Kyung-Kwon;Kim, Mi-Ra;Rhee, Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.2
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    • pp.67-73
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    • 2010
  • We have developed a millimeter-wave passive imaging system with reflector for detection of concealed objects. We have designed a millimeter-wave sensor, control device for reflector control, and a lens for focusing of millimeter-wave signal at center frequency of 94GHz. DC signal from millimeter-wave sensor output is filtered by low pass filter and amplified by video amplifier, and then converted into digital signal by using ADC/DAQ. This signal is image processed by computer, and it is possible to obtain millimeter-wave passive image with resolution of $18{\times}64$ pixel using the fabricated system. It is shown that we can obtain the image of men and concealed object with the system.

Design of Ultrasound Dynamic Focusing Systems (초음파 다이나믹 집속 시스템의 설계)

  • 김진하;김청월
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.21 no.4
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    • pp.65-71
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    • 1984
  • The design formular of optical focusing systems cannot be applied to ultrasonic B scanners, which use broadband pulses instead of continuous wave. In this paper, a calculation method is studied for analyzing the propagation of ultrasonic broadband pulse excited by ultrasonic array transducers. Using the results, seveial design parameters such as the number of transducer elements, delay time, and the focal point are determined to obtain high resolution in the ultrasonic dynamic focusing system. A dynamic focusing system with low-noise switching characteristics; which attains lateral resolution of 2-3mm all along the axial direction up to 18 cm with a 3.5 MHz linear array transducer, was implemented.

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Suggestions for Korea's Corporate Image, Product Image, and Purchase Intention with Consumer Hostility: Focusing on Korean Wave and Satisfaction Variables

  • Bae, Jeong-Min;Lee, Chun-Su
    • East Asian Journal of Business Economics (EAJBE)
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    • v.6 no.4
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    • pp.25-34
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    • 2018
  • Purpose - The purpose of this study is to investigate the effect of Korean Wave on consumer intentions by adjusting the Korean image and image of Korean company to counterbalance the hostility through the control effect of Korean Wave. Research design and methodology - This paper measure individual and national hostility and suggest that the effect of the adjustment of Korean culture satisfaction on corporate image, product image and consumer's purchase intention. Results - This study suggests the subjects to be studied empirically by presenting research themes and models, but it is necessary to verify the model through statistical verification since it is not verified empirically. In addition, it is necessary to further control factors and identification of anti-marginal or anti-marginal products. Conclusions - This study suggests research topics that investigate how hostility affects Korean Wave in consideration of the current special situation, while conventional researches mainly focus on ethnocentrism and patriotism. In this way, this study suggests research direction that helps to enhance corporate image and product image by eliminating hostility and actively utilizing Korean Wave. The Proposal will be helpful to provide a frame for empirical analysis in future and to develop strategic means to further utilize it in international marketing.

Development of Wave Height Field Measurement System Using a Depth Camera (깊이카메라를 이용한 파고장 계측 시스템의 구축)

  • Kim, Hoyong;Jeon, Chanil;Seo, Jeonghwa
    • Journal of the Society of Naval Architects of Korea
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    • v.58 no.6
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    • pp.382-390
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    • 2021
  • The present study suggests the application of a depth camera for wave height field measurement, focusing on the calibration procedure and test setup. Azure Kinect system is used to measure the water surface elevation, with a field of view of 800 mm × 800 mm and repetition rate of 30 Hz. In the optimal optical setup, the spatial resolution of the field of view is 288 × 320 pixels. To detect the water surface by the depth camera, tracer particles that float on the water and reflects infrared is added. The calibration consists of wave height scaling and correction of the barrel distortion. A polynomial regression model of image correction is established using machine learning. The measurement results by the depth camera are compared with capacitance type wave height gauge measurement, to show good agreement.

Experimental and numerical validation of guided wave based on time-reversal for evaluating grouting defects of multi-interface sleeve

  • Jiahe Liu;Li Tang;Dongsheng Li;Wei Shen
    • Smart Structures and Systems
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    • v.33 no.1
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    • pp.41-53
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    • 2024
  • Grouting sleeves are an essential connecting component of prefabricated components, and the quality of grouting has a significant influence on structural integrity and seismic performance. The embedded grouting sleeve (EGS)'s grouting defects are highly undetectable and random, and no effective monitoring method exists. This paper proposes an ultrasonic guided wave method and provides a set of guidelines for selecting the optimal frequency and suitable period for the EGS. The optimal frequency was determined by considering the group velocity, wave structure, and wave attenuation of the selected mode. Guided waves are prone to multi-modality, modal conversion, energy leakage, and dispersion in the EGS, which is a multi-layer structure. Therefore, a time-reversal (TR)-based multi-mode focusing and dispersion automatic compensation technology is introduced to eliminate the multi-mode phase difference in the EGS. First, the influence of defects on guided waves is analyzed according to the TR coefficient. Second, two major types of damage indicators, namely, the time domain and the wavelet packet energy, are constructed according to the influence method. The constructed wavelet packet energy indicator is more sensitive to the changes of defecting than the conventional time-domain similarity indicator. Both numerical and experimental results show that the proposed method is feasible and beneficial for the detection and quantitative estimation of the grouting defects of the EGS.

Impact Localization of a Composite Plate Using a Single Transducer and Spatial Focusing Signal Processing Techniques (단일 센서와 공간집속 신호처리 기술을 이용한 복합재 판에서의 충격위치 결정)

  • Cho, Sungjong;Jeong, Hyunjo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.715-722
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    • 2012
  • A structural health monitoring (SHM) technique for locating impact position in a composite plate is presented in this paper. The technique employs a single sensor and spatial focusing properties of time reversal (TR) and inverse filtering (IF). We first examine the focusing effect of back-propagated signal at the impact position and its surroundings through simulation. Impact experiments are then carried out and the localization images are found using the TR and IF signal processing, respectively. Both techniques provide accurate impact location results. Compared to existing techniques for locating impact or acoustic emission source, the proposed methods have the benefits of using a single sensor and not requiring knowledge of material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in the SHM of plate-like structures.

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