• Title/Summary/Keyword: Micro-object

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A Study on the Thickness Measurement of Thin Film and the Flaw Detection of the Interface by Digital Signal Processing (디지털 신호처리에 의한 박판두께측정 및 접합경계면의 결함검출에 관한 연구)

  • Kim, Jae-Yeol;Yiu, Shin;Kim, Byung-Hyun
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.123-127
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    • 1997
  • Recently, it is gradually raised necessity that interface is measured accurately and managed in industrial circles and medical world, An Ultrasonic wave transmitted from a focused beam transducer is being expected as a powerful tool for NDE of micro-defect. The ultrasonic NDE of the defect is based on the form of the wave reflected form the interface In this study, regarding to the thickness of film which is in opaque object and thickness measurement was done by MEM-cepstrum analysis of received ultrasonic wave. In measument results, film thickness which is beyond distance resolution capacity was measured accurately. Also, automatically repeated discrimination analysis method can be decided in the category of all kinds of defects on semiconductor package.

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Impact analysis of composite plate by multiscale modeling (멀티스케일 모델링에 의한 복합재료 평판의 충격해석)

  • Ji Kuk Hyun;Paik Seung Hoon;Kim Seung Jo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.67-70
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    • 2004
  • An investigation was performed to study the impact damage of the laminated composite plates caused by a low- velocity foreign object with multi-scale modeling based on the concepts of Direct Numerical Simulation (DNS)[4]. In the micro-scale part, we discretize the composite plates through separate modeling of fiber and matrix for the local microscopic analysis. A micro-scalemodel was developed for predicting the initiation of the damage and the extent of the final damage as a function of material properties, laminate configuration and the impactor's mass, etc. Anda macro-scale model was developed for description of global dynamic behavior. The connection betweenmicroscopic and macroscopic is implemented by the tied interface constraints of LS-DYNA contact card. A transient dynamic finite element analysis was adopted for calculating the contact force history and the stresses and strains inside the composites during impact resulting from a point-nose impactor. The low-velocity impact events such as contact force, deformation, etc. are simulated in the macroscopic sense and the impact damages, fiber-breakage, matrix cracking and delamination etc. are examined in the microscopic sense.

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Development of Young Children's Understanding of Representational Relations (표상적 관계에 대한 영유아의 이해와 발달)

  • Park, Chan-Hyung;Lee, Jong-Hee
    • Korean Journal of Child Studies
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    • v.32 no.1
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    • pp.51-69
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    • 2011
  • This study examined how young children understand representational relations between referents and their representational objects. Ninety-four children aged 2- to 4.5-years of age were individually tested; firstly in the scale-model tasks, and then in the scale-map tasks. Data were analyzed both by means of Chi-Square test and by a more descriptive, micro analysis. According to the results, there were significant age differences in the understanding of representational relations, regardless of the type of representational objects. In the descriptive, micro analysis, it was found that before 3 years of age, young children have a great deal of difficulties in understanding representational relations. More importantly, young children under three seemed unable to understand representational relations, especially when the similarities as well as the differences between the representational object and the referent were very high. These results suggest that teachers of very young children need to select representational materials carefully, taking into consideration children's understanding of representational relations.

Icon and Form: A Study on Iconic Images of Cultural Revolution in Contemporary Chinese Fine Art (도상과 형상: 중국현대미술에서 문혁의 도상이미지 연구)

  • Li, Yongri
    • The Journal of Art Theory & Practice
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    • no.16
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    • pp.225-256
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    • 2013
  • As the great catastrophe in the modern and contemporary history of China, the Cultural Revolution(CR) is an object, which must have sutured the past of darkness. At the same time it is a continuous event and also a scar of memory. In other words, for history is "a dialog between the past and the reality"(E.H.Kar), CR intervenes in the reality and, on the contrary, the reality recomposes CR. From this point of view, CR is a historical event, which so far is not ended, and it is an object of memory, which is still being composed at the moment. As the saying: "Poetry is greater than history"(Aristoteles), artistic works more intensively reflect the past. The works related to CR can not be an exception. And CR is endlessly exposed in the contemporary Chinese fine arts and the works of the contemporary Chinese artists-Wang Guangyi, Yue Minjun, Zhang Xiaogang and others are proved to be those who suffer from the trauma of CR and who feel no liberty from CR. For example, CR probably is a symbol showing the "identity" of the Chinese artists. And the diversity of the symbol is the experience and pattern of the dialog between artistic works and CR (i.e., intervention in reality). For example, with withering of grand-narrative and appearance of micro-narrative, the CR critical works of Guan Zhoudao were the root of the Chinese fine arts in the late 70s and early 80s. In the contemporary cultural situation, the literary works about CR actively analyzed the history (CR) from the personal point of views and explained in the way of monolog and micro-method led the 1990s' works. In this way they tried to recompose the history "randomly", like looking at reality with their own eyes. In this process, CR is continuously exposing new features and the real facts are appearing before us as unfamiliar phenomena. This is a way of combination and "reappearance" of contemporary arts and reality. In conclusion, the purpose of this article is to make it possible to see a section of the contemporary Chinese fine arts through the study of the icon image of CR and to analyze the way of fine arts recomposing the history and the intervening in the reality. In this sense, the author has entitled the article "Icon and Form". It means how to reshape (the present) the typically formed icon of the CR (the past).

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A Study on the Mold Fabrication and Molding Technology with Three-dimensional Surface Textures for Smart Phone Case (3차원 질감표현 스마트폰 케이스 제작을 위한 금형 및 성형기술 개발)

  • Kim, Jong-Deok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.1
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    • pp.15-18
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    • 2011
  • Up to now the incomplete texture have been manufactured through the 2D surface treatment like simple painting process or printing process. But in order to obtain 3D texture like natural object, micro scales' 3D surface structure on the surface of plastic part must be formed. In this study plastic smart phone case with 3D texture was produced by developing the surface duplication technology of natural object used electro-forming technology, by developing the press forming technology converted plane stamper to curved surface stamper and by developing the injection mold and molding technology which have been installed the curved surface stamper.

Study of Human Tactile Sensing Characteristics Using Tactile Display System (질감 제시 장치를 이용한 촉감인지 특성 연구)

  • Son Seung-Woo;Kyung Ki-Uk;Yang Gi-Hun;Kwon Dong-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.5
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    • pp.451-456
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    • 2005
  • This paper describes three kinds of experiments and analysis of their results related to human tactile sensitivity using an integrated tactile display system. The device can provide vibration, normal pressure and lateral slip/stretch which are important physical quantities to sense texture. We have tried to find out the efficient method of stimulating, limitation of surface discrimination by kinesthetic farce feedback and the effectiveness of the combination of kinesthetic force and tactile feedback. Seven kinds of different stimulating methods were carried out and they are single or combination of the kinesthetic force, normal static pressure, vibration, active/passive shear and moving wave. Both prototype specimen and stimulus using tactile display were provided to all examinees and they were allowed to answer the most similar sample. The experimental results show that static pressure is proper stimulus for the display of micro shape of the surface and vibrating stimulus is more effective for the display of fine surface. And the sensitivities of active touch and passive touch are compared. Since kinesthetic force feedback is appropriate to display shape and stiffness of an object, but roughness display has a limitation of resolution, the concurrent providing methods of kinesthetic and tactile feedback are applied to simulate physical properties during touching an object.

A Study on the Production of a Convergence Color-Responsive Lighting Bookcase (색상에 반응하는 융복합 조명 책꽂이 제작에 관한 연구)

  • Kang, Hee-Ra
    • Journal of Digital Convergence
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    • v.13 no.6
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    • pp.267-273
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    • 2015
  • Recently, a wide range of products incorporating cutting-edge technology are being introduced in various sectors of design. Belkin's WeMo or Phillips' Hue are representative examples. In this context, the color-responsive lighting bookcase is a design product that would satisfy the needs of contemporary consumers who seek entertainment in their purchases. By installing lightings that change color according to the user's behavior, this design reconceptualizes the bookcase as a source of entertainment rather than a mundane object of household furnishing. The lighting apparatus can be detached and reattached, serving as stand-alone equipment. The lighting bookcase is modularized, comprising extensions equipped with MCU (Micro Controller Unit), RGB LED and color sensors. The bookcase as a whole is extendable towards four directions up to nine units with the lighting bookcase at the center. The extended, multiple lighting bookcases are wired to receive power from the main bookcase, and are equipped with RGB LEDs but not with MCUs or color sensors. Receiving power and color signals from the main lighting bookcase, the sub-bookcases feature changing shades of color. Also, it includes IoT(internet of Things). This study is a proposal of a design product, modularized to control the shades of the bookcase lighting using these sensors.

Application of MicroPACS Using the Open Source (Open Source를 이용한 MicroPACS의 구성과 활용)

  • You, Yeon-Wook;Kim, Yong-Keun;Kim, Yeong-Seok;Won, Woo-Jae;Kim, Tae-Sung;Kim, Seok-Ki
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.1
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    • pp.51-56
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    • 2009
  • Purpose: Recently, most hospitals are introducing the PACS system and use of the system continues to expand. But small-scaled PACS called MicroPACS has already been in use through open source programs. The aim of this study is to prove utility of operating a MicroPACS, as a substitute back-up device for conventional storage media like CDs and DVDs, in addition to the full-PACS already in use. This study contains the way of setting up a MicroPACS with open source programs and assessment of its storage capability, stability, compatibility and performance of operations such as "retrieve", "query". Materials and Methods: 1. To start with, we searched open source software to correspond with the following standards to establish MicroPACS, (1) It must be available in Windows Operating System. (2) It must be free ware. (3) It must be compatible with PET/CT scanner. (4) It must be easy to use. (5) It must not be limited of storage capacity. (6) It must have DICOM supporting. 2. (1) To evaluate availability of data storage, we compared the time spent to back up data in the open source software with the optical discs (CDs and DVD-RAMs), and we also compared the time needed to retrieve data with the system and with optical discs respectively. (2) To estimate work efficiency, we measured the time spent to find data in CDs, DVD-RAMs and MicroPACS. 7 technologists participated in this study. 3. In order to evaluate stability of the software, we examined whether there is a data loss during the system is maintained for a year. Comparison object; How many errors occurred in randomly selected data of 500 CDs. Result: 1. We chose the Conquest DICOM Server among 11 open source software used MySQL as a database management system. 2. (1) Comparison of back up and retrieval time (min) showed the result of the following: DVD-RAM (5.13,2.26)/Conquest DICOM Server (1.49,1.19) by GE DSTE (p<0.001), CD (6.12,3.61)/Conquest (0.82,2.23) by GE DLS (p<0.001), CD (5.88,3.25)/Conquest (1.05,2.06) by SIEMENS. (2) The wasted time (sec) to find some data is as follows: CD ($156{\pm}46$), DVD-RAM ($115{\pm}21$) and Conquest DICOM Server ($13{\pm}6$). 3. There was no data loss (0%) for a year and it was stored 12741 PET/CT studies in 1.81 TB memory. In case of CDs, On the other hand, 14 errors among 500 CDs (2.8%) is generated. Conclusions: We found that MicroPACS could be set up with the open source software and its performance was excellent. The system built with open source proved more efficient and more robust than back-up process using CDs or DVD-RAMs. We believe that the operation of the MicroPACS would be effective data storage device as long as its operators develop and systematize it.

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Simultaneous and Multi-frequency Driving System of Ultrasonic Sensor Array for Object Recognition

  • Park, S.C.;Choi, B.J.;Lee, Y.J.;Lee, S.R.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.582-587
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    • 2004
  • Ultrasonic sensors are widely used in mobile robot applications to recognize external environments, because they are cheap, easy to use, and robust under varying lighting conditions. However, the recognition of objects using a ultrasonic sensor is not so easy due to its characteristics such as narrow beam width and no reflected signal from a inclined object. As one of the alternatives to resolve these problems, use of multiple sensors has been studied. A sequential driving system needs a long measurement time and does not take advantage of multiple sensors. Simultaneous and pulse coding driving system of ultrasonic sensor array cannot measure short distance as the length of the code becomes long. This problem can be resolved by multi-frequency driving of ultrasonic sensors, which allows multi-sensors to be fired simultaneously and adjacent objects to be distinguished. Accordingly, this paper presents a simultaneous and multi-frequency driving system for an ultrasonic sensor array for object recognition. The proposed system is designed and implemented using a DSP and FPGA. A micro-controller board is made using a DSP, Polaroid 6500 ranging modules are modified for firing the multi-frequency signals, and a 5-channel frequency modulated signal generating board is made using a FPGA. To verify the proposed method, experiments were conducted in an environment with overlapping signals, and the flight distances for each sensor were obtained from filtering of the received overlapping signals and calculation of the time-of-flights.

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Development of Digital 3D Real Object Duplication System and Process Technology (디지털 3차원 실물복제기 시스템 및 공정기술 개발)

  • Kim D.S.;An Y.J.;Lee W.H.;Choi B.O.;Chang M.H.;Baek Y.J.;Choi K.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.732-737
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    • 2005
  • Distal 3D Real Object Duplication System(RODS) consists of 3D Scanner and Solid Freeform Fabrication System(SFFS). It is a device to make three-dimensional objects directly from the drawing or the scanning data. In this research, we developed an office type SFFS based on Three Dimensional Printing Process and a industrial SFFS using Dual Laser. An office type SFFS applied sliding mode control with sliding perturbation observer(SMCSPO) algorithm for control of this system. And we measured process variables about droplet diameter measurement and powder bed formation etc. through experiments. Also, in order to develop more elaborate and speedy system for large objects than existing SLS process, this study applies a new Selective Multi-Laser Sintering(SMLS) process and 3-axis dynamic Focusing Scanner for scanning large area instead of the existing $f\theta$ lens. In this process, the temperature has a great influence on sintering of the polymer. Also the laser parameters are considered like that laser beam power, scan speed, scan spacing. Now, this study is in progress to eveluate the effect of experimental parameters on the sintering process.

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