• 제목/요약/키워드: Optical media

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A Study on the Relationship of Space and Time in Visual Tactility (시각과 시촉각에 의한 운동 측면에서 본 공간과 시간의 관계성 연구 - 연경당 외부공간을 중심으로 -)

  • Yook, Ok-Soo
    • Journal of architectural history
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    • v.20 no.1
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    • pp.77-93
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    • 2011
  • Across the culture of Western Europe, dichotomy based on the visual sense has evolved. They believed eyes and ears requiring a distance related in recognition, are more developed than any other human senses in human body. Dominant position, as a condition to using a perspective, the eye has been just concentrated in the development of optical sight. But developed a variety of modern media, highlighting the importance of the other perception, it makes dichotomy to the expansion of perception over the single function of visuality. Recently, Guille Deleuze and Merleau-Ponty try to recover the sense of tactility segregated in skin from body keeping eyes for distance. By the result, the activity can be happened by being connected to the body rather than to eye in the space between the subject and object. From the phase of recognition where the human body tries to identify the object in the space considering a time, it will be changed for the subject to the phase of structure vice versa. Visual tactility is to eliminate the distance between subject and object. If the visual tactility is to erase the distance different from the visual in dichotomy, it will be occurred to having a tension and makes new relationship to work trying to move the subjective point of view in object. Like this evidence in analysis of architecture, it can be easy to find the Korean architecture rather than western architecture in terms of emphasizing the time and space. The fact, architecture of Lee Dynasty had been preserved and consisted basic form and style over the centuries makes us assume that visual tactility was considered as well as the visual sense. This study will be intensive in terms of visual and tactile inherent in the subject and how it is being connected to the movement in the space and time.

Characterization of Microstructure and Thermal property of Ash Deposits on Fire-side Boiler Tube

  • Bang, Jung Won;Lee, Yoon-Joo;Shin, Dong-Geun;Kim, Younghee;Kim, Soo-Ryong;Baek, Chul-Seoung;Kwon, Woo-Teck
    • Journal of the Korean Ceramic Society
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    • v.53 no.6
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    • pp.659-664
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    • 2016
  • Ash deposition of heat exchange boiler, caused mainly by accumulation of particulate matter, reduces heat transfer of the boiler system. Heat and mass transfer through porous media such as ash deposits mainly depend on the microstructure of deposited ash. Therefore, in this study, we investigated microstructural and thermal properties of the ash deposited on the boiler tube. Samples for this research were obtained from the fuel economizer tube in an industrial waste incinerator. To characterize microstructures of the ash deposit samples, scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD) and BET analysis were employed. The results revealed that it had a porous structure with small particles mostly of less than a few micrometers; the contents of Ca and S were 19.3, 22.6% and 18.5, 18.7%, respectively. Also, the results showed that it consisted mainly of anhydrite ($CaSO_4$) crystals. - The thermal conductivities of the ash deposit sample obtained from the economizer tube in industrial waste incinerator were measured to be 0.63 and 0.54 W/mK at $200^{\circ}C$, which were about 100 times less than the thermal conductivity (61.32 W/mK) of the boiler tube itself, indicating that ash deposition on the boiler tube was closely related to a decrease in boiler heat transfer.

Phase Unwrapping using Modified Goldstein Algorithm in Digital Holography (디지털 홀로그래피에서의 수정된 골드스타인 알고리즘을 이용한 위상펼침)

  • Yoon, Seon-Kyu;Cho, Hyung-Jun;Kim, Doo-Cheol;Yu, Young-Hun;Kim, Sung-Kyu
    • Korean Journal of Optics and Photonics
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    • v.18 no.2
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    • pp.122-129
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    • 2007
  • Generally, many kinds of phase unwrapping algorithm are used to obtain three-dimensional features in digital holography. The Goldstein algorithm is ra epresentative method. which requires small memory capacity and short execution time fer an unwrapping process. However, the Goldstein algorithm has some problems when the dipole residue is located at the boundary. When the opposite residues are located at the boundary and the distance between the opposite residues is longer than the boundary, an incorrect branch cut occurs and results in incorrect calculation. We have modified the Goldstein algorithm to solve the incorrect calculation problem using boundary information. We found that the modified Goldstein algorithm could resolve the Goldstein algorithm's problem.

Area storage density of ideal 3-D holographic disk memories (이상적인 디스크형 3차원 홀로그래픽 메모리에서의 면적 저장밀도)

  • 장주석;신동학
    • Korean Journal of Optics and Photonics
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    • v.11 no.1
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    • pp.58-64
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    • 2000
  • Assuming that the performance of holographic storage media is ideal, we estimate the area storage density of disk-type holographic memories, when the method of either angle multiplexing, or rotational multiplexing, or both are used. The area storage density is strongly dependent on the f numbers (ratio of focal length to diameter) of both the Fourier transform lens in the signal arm, denoted by $F/#_2$, and the angle range over which the reference beam is incident (or, the equivalent f number corresponding to the angle range denoted by $F/#_1$). The area storage density is largely independent of the pixel pitch of the spatial light modulator when the Fourier plane holograms are recorded, while it is sensitive to the pixel pitch when the image plane holograms are recorded. In general, to obtain high area storage density, the Fourier or at least near Fourier plane holograms rather than the image plane holograms should be recorded. In addition, when the thickness of the recording materials are less than approximately $500\mu\extrm{m}$, rotational multiplexing gives higher area storage densities than angle multiplexing does. To increase the storage density further, however, it is desirable to use both of the two multiplexing methods in combination.nation.

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A Study on Interactive Information Service based on Augmented Reality (증강현실기반 양방향 정보서비스에 관한 연구)

  • Kim, Yong
    • Journal of Information Management
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    • v.41 no.4
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    • pp.41-67
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    • 2010
  • Augmented reality technology was invented for military purposes at the beginning. But the development of wireless and location based technology in 2000s makes AR services reach the age of innovation. Especially, it attracts attention as a media which enriches our perception. There is a potential that it can extend the virtual information in the real world from optical sense to auditory, tactile, and olfactory sense. This study proposed the interactive information service system and method based on AR. To do it, technical background on AR was analyzed and a method to apply the technology was examined. Especially, as a eco service, this study proposed new information service using 2D bar code in a library for user need and convenience in ubiquitous environment. The proposed service system can optimize practical utilization of information resources in virtual and real reality as consolidating analog and digital resources in a library.

Extremely High-Definition Computer Generated Hologram Calculation Algorithm with Concave Lens Function (오목 렌즈 함수를 이용한 초 고해상도 Computer generated hologram 생성 기법)

  • Lee, Chang-Joo;Choi, Woo-Young;Oh, Kwan-Jung;Hong, Keehoon;Choi, Kihong;Cheon, Sang-Hoon;Park, Joongki;Lee, Seung-Yeol
    • Journal of Broadcast Engineering
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    • v.25 no.6
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    • pp.836-844
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    • 2020
  • A very large number of pixels is required to generate a computer generated hologram (CGH) with a large-size and wide viewing angle equivalent to that of an analog hologram, which incurs a very large amount of computation. For this reason, a high-performance computing device and long computation time were required to generate high-definition CGH. To solve these problems, in this paper, we propose a technique for generating high-definition CGH by arraying the pre-calculated low-definition CGH and multiplying the appropriately-shifted concave lens function. Using the proposed technique, 0.1 Gigapixel CGH recorded by the point cloud method can be used to calculate 2.5 Gigapixels CGH at a very high speed, and the recorded hologram image was successfully reconstructed through the experiment.

A Disk-based Archival Storage System Using the EOS Erasure Coding Implementation for the ALICE Experiment at the CERN LHC

  • Ahn, Sang Un;Betev, Latchezar;Bonfillou, Eric;Han, Heejune;Kim, Jeongheon;Lee, Seung Hee;Panzer-Steindel, Bernd;Peters, Andreas-Joachim;Yoon, Heejun
    • Journal of Information Science Theory and Practice
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    • v.10 no.spc
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    • pp.56-65
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    • 2022
  • Korea Institute of Science and Technology Information (KISTI) is a Worldwide LHC Computing Grid (WLCG) Tier-1 center mandated to preserve raw data produced from A Large Ion Collider Experiment (ALICE) experiment using the world's largest particle accelerator, the Large Hadron Collider (LHC) at European Organization for Nuclear Research (CERN). Physical medium used widely for long-term data preservation is tape, thanks to its reliability and least price per capacity compared to other media such as optical disk, hard disk, and solid-state disk. However, decreasing numbers of manufacturers for both tape drives and cartridges, and patent disputes among them escalated risk of market. As alternative to tape-based data preservation strategy, we proposed disk-only erasure-coded archival storage system, Custodial Disk Storage (CDS), powered by Exascale Open Storage (EOS), an open-source storage management software developed by CERN. CDS system consists of 18 high density Just-Bunch-Of-Disks (JBOD) enclosures attached to 9 servers through 12 Gbps Serial Attached SCSI (SAS) Host Bus Adapter (HBA) interfaces via multiple paths for redundancy and multiplexing. For data protection, we introduced Reed-Solomon (RS) (16, 4) Erasure Coding (EC) layout, where the number of data and parity blocks are 12 and 4 respectively, which gives the annual data loss probability equivalent to 5×10-14. In this paper, we discuss CDS system design based on JBOD products, performance limitations, and data protection strategy accommodating EOS EC implementation. We present CDS operations for ALICE experiment and long-term power consumption measurement.

Molybdenum-Based Electrocatalysts for Direct Alcohol Fuel Cells: A Critical Review

  • Gaurav Kumar Yogesh;Rungsima Yeetsorn;Waritnan Wanchan;Michael Fowler;Kamlesh Yadav;Pankaj Koinkar
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.67-95
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    • 2024
  • Direct alcohol fuel cells (DAFCs) have gained much attention as promising energy conversion devices due to their ability to utilize alcohol as a fuel source. In this regard, Molybdenum-based electrocatalysts (Mo-ECs) have emerged as a substitution for expensive Pt and Ru-based co-catalyst electrode materials in DAFCs, owing to their unique electrochemical properties useful for alcohol oxidation. The catalytic activity of Mo-ECs displays an increase in alcohol oxidation current density by several folds to 1000-2000 mA mgPt-1, compared to commercial Pt and PtRu catalysts of 10-100 mA mgPt-1. In addition, the methanol oxidation peak and onset potential have been significantly reduced by 100-200 mV and 0.5-0.6 V, respectively. The performance of Mo-ECs in both acidic and alkaline media has shown the potential to significantly reduce the Pt loading. This review aims to provide a comprehensive overview of the bifunctional mechanism involved in the oxidation of alcohols and factors affecting the electrocatalytic oxidation of alcohol, such as synthesis method, structural properties, and catalytic support materials. Furthermore, the challenges and prospects of Mo-ECs for DAFCs anode materials are discussed. This in-depth review serves as valuable insight toward enhancing the performance and efficiency of DAFC by employing Mo-ECs.

A Study of Legibility by Monitor Letter Color with an Eye Tracker (아이트래커를 이용한 모니터 글자 색상에 따른 가독성에 대한 연구)

  • Kim, Ha-Rim;Kim, Soo-Hyun;Shin, Dong-Min;Jeong, Hee-Young;Kim, Young-Gil;Kim, Tae-Hong;Seo, Jae-Myoung;Jeong, Ju-Hyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.19 no.2
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    • pp.279-284
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    • 2014
  • Purpose: This study will be a basic research providing data which can reduce eye strain using monitor and electric media by measuring legibility of text color on monitor. Methods: Total experimental subjects who don't have color anomaly and best corrected visual acuity was over 1.0 were 50 and their mean age was $22.83{\pm}1.47$. Reading speed test were carried out with 163 words and subjects who could read over 123 words were selected for legibility examination. Monitor background color was white and letter colors were black, blue, red, and yellow for the legibility examination. Results: In case of text color of black, blue, red, and yellow, Event duration(sec) was measured to 41.89, 42.89, 45.32, and 56.28, respevtively, and reading error (number) was measured to 1.94, 2.74, 3.36, and 5.14. Average of fixation duration(sec) was measured to 0.25, 0.26, 0.27, and 0.32. Conclusions: In this paper, event Duration, reading error and average of fixation duration which can measure the legibility was reduced in a sequence of black blue, red, and yellow.

FOUR-YEAR SURVIVAL RATE OF RBM SURFACE INTERNAL CONNECTION NON-SUBMERGED IMPLANTS AND THE CHANGE OF THE PERI-IMPLANT CRESTAL BONE (RBM 표면처리 내부연결형 비매립 임플란트의 4년 생존율과 주변골 흡수에 관한 임상 및 방사선학적 연구)

  • Jeon, Hye-Ran;Kim, Myung-Rae;Lee, Dong-Hyun;Shin, Jung-Sub;Kang, Na-Ra
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.31 no.3
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    • pp.237-242
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    • 2009
  • Implant-supported fixed and removable prostheses provide a proper treatment modality with reliable success. The SS $II^{(R)}$ Implants is a one-stage nonsubmerged threaded titanium implants with Resorbable Blasting Media (RBM) surface developed by Osstem company (Busan, Korea) in October of 2002. This study is to evaluate the survival rate of the SS $II^{(R)}$ Implants for 4 years using radiographic parameters and to review the retrieved implants by the cytotoxicity tests. Since September 2003, 439 SS $II^{(R)}$ implants had been used for 173 patients at Ewha Womans University Medical Center in Korea. Patients consisted of 91 females (52.6 %) and 82 males (47.4 %). The patients' mean age was $42\;{\pm}16$ years, ranging from 21 to 83 years. The follow-up period ranged from 9 to 46 months (mean F/U $24.2\;{\pm}\;10.2$ months). The results are as follows; 1. Of 439 implants, 17 implants were removed and 4-year cumulative survival rate was 96.1%. 2. 82.3% of 17 failed implants were founded during healing phase, and 94.1% of failed fixtures were removed within 5 months after implantation. 3. Crestal bone around the implants was resorbed to 1 mm in 89.0%, to 1 - 2 mm loss of the marginal bone in 8.3%, and the bone loss over 2 mm was occurred in 2.7%. 4. Microscopic examination of the retrieved implants disclosed Grade 0 cytotoxicity in 4 and Grade 1 cytotoxicity in 2 of 6 groups divided according to LOT numbers. Inhibition rate with optical density was acceptable as low as ISO standard.