• 제목/요약/키워드: Digital Materials

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Evaluation of trueness and precision of removable partial denture metal frameworks manufactured with digital technology and different materials

  • Leonardo Ciocca;Mattia Maltauro;Elena Pierantozzi;Lorenzo Breschi;Angela Montanari;Laura Anderlucci;Roberto Meneghello
    • The Journal of Advanced Prosthodontics
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    • 제15권2호
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    • pp.55-62
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    • 2023
  • PURPOSE. The aim of this study is to evaluate the accuracy of removable partial denture (RPD) frameworks produced using different digital protocols. MATERIALS AND METHODS. 80 frameworks for RPDs were produced using CAD-CAM technology and divided into four groups of twenty (n = 20): Group 1, Titanium frameworks manufactured by digital metal laser sintering (DMLS); Group 2, Co-Cr frameworks manufactured by DMLS; Group 3, Polyamide PA12 castable resin manufactured by multi-jet fusion (MJF); and Group 4, Metal (Co-Cr) casting by using lost-wax technique. After the digital acquisition, eight specific areas were selected in order to measure the Δ-error value at the intaglio surface of RPD. The minimum value required for point sampling density (0.4 mm) was derived from the sensitivity analysis. The obtained Δ-error mean value was used for comparisons: 1. between different manufacturing processes; 2. between different manufacturing techniques in the same area of interest (AOI); and 3. between different AOI of the same group. RESULTS. The Δ-error mean value of each group ranged between -0.002 (Ti) and 0.041 (Co-Cr) mm. The Pearson's Chi-squared test revealed significant differences considering all groups paired two by two, except for group 3 and 4. The multiple comparison test documented a significant difference for each AOI among group 1, 3, and 4. The multiple comparison test showed significant differences among almost all different AOIs of each group. CONCLUSION. All Δ-mean error values of all digital protocols for manufacturing RPD frameworks optimally fit within the clinical tolerance limit of trueness and precision.

Research and Development of High Performance 50-inch HD Plasma Display Panel

  • Choi, Kwang-Yeol;Min, Woong-Kee;Rhee, Byung-Joon;Ahn, Byung-Nam;Kim, Je-Seok;Moon, Won-Seok;Park, Min-Soo;Ryu, Byung-Gil;Kim, Sung-Tae;Ahn, Young-Joon;Yang, Sung-Soo;Kim, Kyung-Tae;Lee, Kyu-Sung
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1547-1550
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    • 2008
  • We are suggesting a new index to represent the performance of PDP, such as Specific Performance Index (SPI) that includes luminous efficacy and panel reflectance. High Xe gas mixture and low panel capacitance are well known as key factors to improve luminous efficacy of PDP [1]. However, higher driving voltage and longer discharge time lag is an obstacle when applying these technologies. Modified cell design, new materials and driving waveform enable us to overcome these obstacles. High efficient phosphor is also a key material to improve luminous efficacy. Phosphors coated with pigment are used to reduce panel reflectance. High performance 50-inch HD PDP with luminous efficacy of 2.3 lm/W has been developed.

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역사기록물(Archives)의 항구적인 보존화 이용 : 보존전략과 디지털정보화 (Permanent Preservation and Use of Historical Archives : Preservation Issues Digitization of Historical Collection)

  • 이상민
    • 기록학연구
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    • 제1호
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    • pp.23-76
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    • 2000
  • In this paper, I examined what have been researched and determined about preservation strategy and selection of preservation media in the western archival community. Archivists have primarily been concerned with 'preservation' and 'use' of archival materials worth of being preserved permanently. In the new information era, preservation and use of archival materials were faced with new challenge. Life expectancy of paper records was shortened due to acidification and brittleness of the modem papers. Also emergence of information technology affects the traditional way of preservation and use of archival materials. User expectations are becoming so high technology-oriented and so complicated as to make archivists act like information managers using computer technology rather than traditional archival handicraft. Preservation strategy plays an important role in archival management as well as information management. For a cost-effective management of archives and archival institutions, preservation strategy is a must. The preservation strategy encompasses all aspects of archival preservation process and practices, from selection of archives, appraisal, inventorying, arrangement, description, conservation, microfilming or digitization, archival buildings, and access service. Those archival functions should be considered in their relations to each other to ensure proper preservation of archival materials. In the integrated preservation strategy, 'preservation' and 'use' should be combined and fulfilled without sacrificing the other. Preservation strategy planning is essential to determine the policies of archives to preserve their holdings safe and provide people with a maximum access in most effective ways. Preservation microfilming is to ensure permanent preservation of information held in important archival materials. To do this, a detailed standardization has been developed to guarantee the permanence of microfilm as well as its product quality. Silver gelatin film can last up to 500 years in the optimum storage environment and the most viable option for permanent preservation media. ISO and ANIS developed such standards for the quality of microfilms and microfilming technology. Preservation microfilming guidelines was also developed to ensure effective archival management and picture quality of microfilms. It is essential to assess the need of preservation microfilming. Limit in resources always put a restraint on preservation management. Appraisal (and selection) of what to be preserved was the most important part of preservation microfilming. In addition, microfilms with standard quality can be scanned to produce quality digital images for instant use through internet. As information technology develops, archivists began to utilize information technology to make preservation easier and more economical, and to promote use of archival materials through computer communication network. Digitization was introduced to provide easy and universal access to unique archives, and its large capacity of preserving archival data seems very promising. However, digitization, i.e., transferring images of records to electronic codes, still, needs to be standardized. Digitized data are electronic records, and st present electronic records are very unstable and not to be preserved permanently. Digital media including optical disks materials have not been proved as reliable media for permanent preservation. Due to their chemical coating and physical character using light, they are not stable and can be preserved at best 100 years in the optimum storage environment. Most CD-R can last only 20 years. Furthermore, obsolescence of hardware and software makes hard to reproduce digital images made from earlier versions. Even if when reformatting is possible, the cost of refreshing or upgrading of digital images is very expensive and the very process has to be done at least every five to ten years. No standard for this obsolescence of hardware and software has come into being yet. In short, digital permanence is not a fact, but remains to be uncertain possibility. Archivists must consider in their preservation planning both risk of introducing new technology and promising possibility of new technology at the same time. In planning digitization of historical materials, archivists should incorporate planning for maintaining digitized images and reformatting them in the coming generations of new applications. Without the comprehensive planning, future use of the expensive digital images will become unavailable. And that is a loss of information, and a final failure of both 'preservation' and 'use' of archival materials. As peter Adelstein said, it is wise to be conservative when considerations of conservations are involved.

A Study on the Automated Compliance Test System for the LSD Protocol Providing the Digital Library Lending Model

  • Kim, Tae-Hyun;Yoon, Hee-Don;Kang, Ho-Gap;Cho, Seung-Hwan
    • 한국컴퓨터정보학회논문지
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    • 제22권4호
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    • pp.51-58
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    • 2017
  • Research on the Development of EPUB SCP(Secure Content Protection) Technical Specification and International Standardization has been carried out as a R&D project granted by the Korea Copyright Commission since 2014. The research aims to build a standard framework for the EPUB DRM(Digital Rights Management) based on the Readium LCP(Licensed Content Protection) and KS EPUB DRM specifications, to develop element technologies for the framework, and to standardize it as an IDPF(International Digital Publishing Forum) industrial standard. One of the essential features of the EPUB DRM developed though this study is to support the lending model of the digital library. This paper introduces LSD(License Status Document) specification which is a DRM license management protocol for the digital library lending process, and also represents a model which can automatically test the implemented entities of the LSD specification, test scenarios and test materials.

임상가를 위한 특집 3 - 여러 보철 치료 술식에 따른 바른 스캐닝 과정과 구강스캐너의 활용 (Suitable scanning procedures for various prosthodontic treatments and the utilization of intraoral scanner)

  • 박지만;박은진;허성주
    • 대한치과의사협회지
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    • 제52권6호
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    • pp.354-362
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    • 2014
  • With the development of digital dentistry, various intra-oral scanners which acquire intraoral image without conventional impression taking and stone pouring steps have been introduced. Fixed dental prostheses such as inlay, onlay, crown, and bridge fabricated by CAD/CAM technique combined with digital impressions is getting popular due to the recent rapid progress of digital impression taking system. In comparison with traditional prosthetic procedure, the advantages of intraoral image acquiring and CAD/CAM technique are as follows; the omission of conventional impression materials, reduced workflow step, and increased efficiency by online communication with clinic and laboratory. This review article covers some opinions about the suitable scanning procedures for the various prosthodontic treatments and the utilization of digital intraoral scanner and CAD/CAM system.

난성형부품의 성형공정개발을 위한 디지털트라이아웃 (Digital Tryout Technique for the Conventional Stamping Process of Hard-to-Form Parts)

  • 심현보
    • 소성∙가공
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    • 제22권2호
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    • pp.93-100
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    • 2013
  • A tryout is a series of process optimization for robust stamping before transfer to the press shop. During tryout, the drawbead control, blank shape determination, binder surface modification, etc., are carried out mainly by a trial-and-error approach. As the level of difficulty of the stamping process increases, the formability becomes more sensitive to the contour of deformed shape, i.e. the blank shape. A digital tryout technique, which simulates a real tryout process, is proposed in this study for challenging stamping processes. Since digital tryout is carried out on a desktop, not in a press shop, a precise control of the deformed contour can be achieved if an optimal blank design technique is utilized. In this work, the proposed digital tryout technique is validated by successful applications to different automotive parts.

Change Detection 기법을 이용한 구조물 안전진단측량 (Safety Inspection Surveying using Change Detection Technique)

  • 최철웅;곽재하;강인준
    • 대한공간정보학회지
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    • 제3권2호
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    • pp.151-158
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    • 1995
  • Change detection기법은 영상에서 차이를 알아내기 위하여 가장 많이 사용되는 방법이며 다양한 영상환경에 사용된다. 수치지형모델과 수치영상은 같은 수치격자데이타 구조를 가지므로 Change detection기법을 수치지형모델에 적용할 측량결과의 표고데이타를 불규칙삼각형(TIN)으로부터 격자구조로 변환하고 수치지형모델화하여 구조물의 변형지점을 찾는데 사용함으로 많은 소모성 자재와 인력을 줄일 수 있었다. 그 결과를 가시화하여 건물의 변형이 발생한 지점과 변형향을 수치적으로 나타낼 수 있었다.

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A Study on the Effective Production of Game Weapons Using ZBrush

  • YunChao Yang;Xinyi Shan;Jeanhun Chung
    • International Journal of Advanced Culture Technology
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    • 제11권2호
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    • pp.397-402
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    • 2023
  • With the rapid adoption of 5G, the gaming industry has undergone significant innovation, with the quality of game content and player experience becoming the focal point of attention. ZBrush, as a professional digital sculpting software, plays a crucial role in the production of 3D game models. In this paper, we explore the application methods and techniques of ZBrush in game weapons production through specific case analyses. We provide a detailed analysis of two game weapon models, discussing the design and modeling process, lowto-high poly conversion, UV unwrapping and texture baking, material texture creation and optimization, and final rendering. By comparing the production process and analyzing the advantages and disadvantages of ZBrush, we establish a theoretical foundation for further design research and provide reference materials for game industry professionals, aiming to achieve higher quality and efficiency in 3D game model production.

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals

  • Mohtavipour, Seiedeh Tahereh;Dalili, Zahra;Azar, Nasim Gheshlaghi
    • Imaging Science in Dentistry
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    • 제41권1호
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    • pp.7-10
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    • 2011
  • Purpose : The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Materials and Methods : Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-$15^{\circ}$, 15-$30^{\circ}$, > $30^{\circ}$). After the placement of a 15 K-file, radiographs were taken with a conventional film (Fspeed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. Results : There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. Conclusion : The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

Skin entrance dose for digital and film radiography in Korean dental schools

  • Cho Eun-Sang;Choi Kun-Ho;Kim Min-Gyu;Lim Hoi-Jeong;Yoon Suk-Ja;Kang Byung-Cheol
    • Imaging Science in Dentistry
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    • 제35권4호
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    • pp.203-205
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    • 2005
  • Purpose: This study was aimed to compare skin entrance dose of digital radiography with that of film radiography and to show the dose reduction achievement with digital systems at 11 dental schools in Korea. Materials and Methods: Forty six intraoral radiographic systems in 11 dental schools were included in this study. Digital sensors were used in 33 systems and film was used in 13 systems. Researchers and the volunteer visited 11 dental schools in Korea. Researchers asked the radiologic technician (s) at each school to set the exposure parameters and aiming the x-ray tube for the periapical view of the mandibular molar of the volunteer. The skin entrance doses were measured at the same exposure parameters and distance by the technician for each system with a dosimeter (Multi-O-Meter : Unfors instruments, Billdal, Sweden). Results: The median dose was $491.2{\mu}Gy$ for digital radiography and $1,205.0{\mu}Gy$ for film radiography. The skin entrance dose in digital radiography was significantly lower than that of film radiography (p<0.05). Conclusion: Fifty-nine percent skin entrance dose reduction with digital periapical radiography was achieved over the film radiography in Korean dental schools.

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