• Title/Summary/Keyword: Computer-aided evaluation

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Evaluation and Optimization of Power Electronic Converters using Advanced Computer Aided Engineering Techniques

  • Oza, Ritesh;Emadi, Ali
    • Journal of Power Electronics
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    • v.3 no.2
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    • pp.69-80
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    • 2003
  • Computer aided engineering (CAE) is a systematic approach to develop a better product/application with maximum possible options and minimum transition time. This paper presents a comprehensive feasibility analysis of various CAE techniques for evaluation and optimization of power electronic converters and systems. Different CAE methods for analysis, design, and performance improvement are classified. In addition, their advantages compared to the conventional workbench experimental methods are explained in detail and through examples.

Expert System for Computer-aided Environmental Planning Tasks Methodology of Computer-aided Evaluation (독일의 환경영향평가를 위한 컴퓨터 전문가 시스템)

  • Weiland, U.;Pietsch, J.;Hubner, M.
    • Journal of Environmental Impact Assessment
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    • v.2 no.2
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    • pp.85-93
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    • 1993
  • Aims of the EXCEPT project and tasks and characteristics of the EXCEPT system are presented based on an analysis of urban planning EIAs. The methodology of evaluation in EIAs, which had to be developed in order to program the system, is based on a model of evaluation processes. Evaluation principles, evaluation rates, an environmental model and a model of the projects being planned are presented. The evaluation concern re-unifies the different components of evaluation again.

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Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems

  • Park, Jong-Kyoung;Lee, Wan-Sun;Kim, Hae-Young;Kim, Woong-Chul;Kim, Ji-Hwan
    • The Journal of Advanced Prosthodontics
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    • v.7 no.2
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    • pp.122-128
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    • 2015
  • PURPOSE. To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS. Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (${\alpha}$=.05), respectively. RESULTS. The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION. Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (< $120{\mu}m$). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

Computer-aided design/computer-aided manufacturing of hydroxyapatite scaffolds for bone reconstruction in jawbone atrophy: a systematic review and case report

  • Garagiola, Umberto;Grigolato, Roberto;Soldo, Rossano;Bacchini, Marco;Bassi, Gianluca;Roncucci, Rachele;De Nardi, Sandro
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.38
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    • pp.2.1-2.9
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    • 2016
  • Background: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. Method: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. Results: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. Conclusions: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to $1200{\mu}m$ had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.

Current status and future perspectives of CAD/CAM fabricated complete denture (임상가를 위한 특집 2 - CAD/CAM 기술을 이용한 총의치 제작의 현재와 전망)

  • Park, Chan-Jin
    • The Journal of the Korean dental association
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    • v.52 no.6
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    • pp.346-353
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    • 2014
  • Currently, computer-aided technology becomes one of main issues in clinical dentistry. About 25 years ago, the development of dental CAD/CAM systems for the fabrication of crowns and fixed partial dentures leads to be able to fabricate complete denture today. The fabrication of milled complete denture prostheses with digital scanning technology may decrease the number of patient appointments. However, the precise tooth arrangement and evaluation by patient is not promising relatively. The purpose of this review was to analyze the existing literature on computer aided technology for fabricating complete denture with historical background, current status, and future perspectives. In addition, two available commercial systems were introduced.

Computer-aided tester for non-destructive determination of material properties

  • Neumaier, Peter
    • Journal of the Korean Society for Nondestructive Testing
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    • v.7 no.2
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    • pp.52-57
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    • 1988
  • This article presents a newly developed equipment system for computer-aided, magneto-inductive testing of metals for material properties. The advantages of ultramodern computer technology over conventional test mothods are illustrated, in particular the greatly simplified equipment adjustment and the extended possibilities of test data evaluation. The characterisitics of the new system of equipment are demonstrated by way of practical testing examples.

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Trueness and precision of scanning abutment impressions and stone models according to dental CAD/CAM evaluation standards

  • Jeon, Jin-Hun;Hwang, Seong-Sig;Kim, Ji-Hwan;Kim, Woong-Chul
    • The Journal of Advanced Prosthodontics
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    • v.10 no.5
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    • pp.335-339
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    • 2018
  • PURPOSE. The purpose of the present study was to compare scanning trueness and precision between an abutment impression and a stone model according to dental computer-aided design/computer-aided manufacturing (CAD/CAM) evaluation standards. MATERIALS AND METHODS. To evaluate trueness, the abutment impression and stone model were scanned to obtain the first 3-dimensional (3-D) stereolithography (STL) file. Next, the abutment impression or stone model was removed from the scanner and re-fixed on the table; scanning was then repeated so that 11 files were obtained for each scan type. To evaluate precision, the abutment impression or stone model was scanned to obtain the first 3-D STL file. Without moving it, scanning was performed 10 more times, so that 11 files were obtained for each scan type. By superimposing the first scanned STL file onto the other STL files one by one, 10 color-difference maps and reports were obtained; i.e., 10 experimental scans per type. The independent t-test was used to compare root mean square (RMS) data between the groups (${\alpha}=.05$). RESULTS. The $RMS{\pm}SD$ values of scanning trueness of the abutment impression and stone model were $22.4{\pm}4.4$ and $17.4{\pm}3.5{\mu}m$, respectively (P<.012). The $RMS{\pm}SD$ values of scanning precision of the abutment impression and stone model were $16.4{\pm}2.9$ and $14.6{\pm}1.6{\mu}m$, respectively (P=.108). CONCLUSION. There was a significant difference in scanning trueness between the abutment impression and stone model, as evaluated according to dental CAD/CAM standards. However, all scans showed high trueness and precision.

Accuracy evaluation of dental models manufactured by CAD/CAM milling method and 3D printing method

  • Jeong, Yoo-Geum;Lee, Wan-Sun;Lee, Kyu-Bok
    • The Journal of Advanced Prosthodontics
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    • v.10 no.3
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    • pp.245-251
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    • 2018
  • PURPOSE. To evaluate the accuracy of a model made using the computer-aided design/computer-aided manufacture (CAD/CAM) milling method and 3D printing method and to confirm its applicability as a work model for dental prosthesis production. MATERIALS AND METHODS. First, a natural tooth model (ANA-4, Frasaco, Germany) was scanned using an oral scanner. The obtained scan data were then used as a CAD reference model (CRM), to produce a total of 10 models each, either using the milling method or the 3D printing method. The 20 models were then scanned using a desktop scanner and the CAD test model was formed. The accuracy of the two groups was compared using dedicated software to calculate the root mean square (RMS) value after superimposing CRM and CAD test model (CTM). RESULTS. The RMS value ($152{\pm}52{\mu}m$) of the model manufactured by the milling method was significantly higher than the RMS value ($52{\pm}9{\mu}m$) of the model produced by the 3D printing method. CONCLUSION. The accuracy of the 3D printing method is superior to that of the milling method, but at present, both methods are limited in their application as a work model for prosthesis manufacture.

An Electronic Colon Cleansing Method using a Patient Colon CT Profile (환자 대장 CT 프로파일을 이용한 전자적 장세척 방법)

  • Kim, Han-Byul;Kim, Dong-Sung
    • Journal of KIISE:Software and Applications
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    • v.35 no.8
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    • pp.493-500
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    • 2008
  • This paper proposes an electronic colon cleansing method using a patient CT profile for a virtual colonoscopy. The proposed method extracts the colon using cubic seeded region growing, and removes tagged materials adjacent to the colon. Residuals produced by a partial volume effect at the boundary of air-tagged material are deleted, and the removed soft tissue pixels due to a partial volume effect at the boundary of tagged material-soft tissue are recovered using a patient CT profile. The proposed method was applied to 16 virtual colonoscopy patient data sets, and produced promising results by a subjective evaluation of a radiologist and by a quantitative evaluation of a computer-aided diagnosis system.