scholarly journals Quasi-Isometric Mesh Parameterization Using Heat-Based Geodesics and Poisson Surface Fills

Mathematics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 753
Author(s):  
Daniel Mejia-Parra ◽  
Jairo R. Sánchez ◽  
Jorge Posada ◽  
Oscar Ruiz-Salguero ◽  
Carlos Cadavid
Keyword(s):  
Piecewise Linear ◽  
Heat Propagation ◽  
Isometric Mapping ◽  
Central Process ◽  
Mesh Parameterization ◽  
Cad Cam ◽  
Euclidean Distances ◽  
Geodesic Distances ◽  
The Difference ◽  
Temperature Maps

In the context of CAD, CAM, CAE, and reverse engineering, the problem of mesh parameterization is a central process. Mesh parameterization implies the computation of a bijective map ϕ from the original mesh M ∈ R 3 to the planar domain ϕ ( M ) ∈ R 2 . The mapping may preserve angles, areas, or distances. Distance-preserving parameterizations (i.e., isometries) are obviously attractive. However, geodesic-based isometries present limitations when the mesh has concave or disconnected boundary (i.e., holes). Recent advances in computing geodesic maps using the heat equation in 2-manifolds motivate us to revisit mesh parameterization with geodesic maps. We devise a Poisson surface underlying, extending, and filling the holes of the mesh M. We compute a near-isometric mapping for quasi-developable meshes by using geodesic maps based on heat propagation. Our method: (1) Precomputes a set of temperature maps (heat kernels) on the mesh; (2) estimates the geodesic distances along the piecewise linear surface by using the temperature maps; and (3) uses multidimensional scaling (MDS) to acquire the 2D coordinates that minimize the difference between geodesic distances on M and Euclidean distances on R 2 . This novel heat-geodesic parameterization is successfully tested with several concave and/or punctured surfaces, obtaining bijective low-distortion parameterizations. Failures are registered in nonsegmented, highly nondevelopable meshes (such as seam meshes). These cases are the goal of future endeavors.

scholarly journals Piecewise linear discretization of Symbolic Implicit Monte Carlo radiation transport in the difference formulation

2006 ◽  
Vol 220 (1) ◽  
pp. 471-497 ◽  
Author(s):  
Eugene D. Brooks ◽  
Abraham Szőke ◽  
Jayson D.L. Peterson
Keyword(s):  
Monte Carlo ◽  
Radiation Transport ◽  
Piecewise Linear ◽  
The Difference

scholarly journals Effect of CAD/CAM Ceramic Thickness on Shade Masking Ability of Discolored Teeth: In Vitro Study

2021 ◽  
Vol 18 (24) ◽  
pp. 13359
Author(s):  
Passent Ellakany ◽  
Marwa Madi ◽  
Nourhan M. Aly ◽  
Zainb S. Al-Aql ◽  
Maher AlGhamdi ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Total Sample ◽  
Dental Restoration ◽  
Vitro Study ◽  
Tooth Structure ◽  
Die Materials ◽  
Cad Cam ◽  
The Difference ◽  
Ceramic Thickness

Shade matching is a common challenge that dentists face during fabrication of esthetic dental restoration. Thus, the aim of the current study was to assess the masking ability of two types of CAD/CAM ceramics for gaining high esthetic prosthesis. This in vitro study used a total sample size of 66 lithium disilicate (LD) and leucite reinforced (LR) CAD/CAM ceramics sub-grouped into three thicknesses: 0.5, 1, and 1.5 mm. Nine shades of natural dentin die materials were prepared as a replica of the underlying tooth structure. The difference in color (ΔE) and translucency parameter (TP) were assessed for both tested ceramics at the three thicknesses. One-way ANOVA was performed to compare the three thicknesses of each ceramic, followed by multiple pairwise comparisons between both ceramics. LR had significantly higher ΔE than LD at all thicknesses used unlike the case in TP. Thickness of 0.5 mm exhibited the highest ΔE and TP, while 1.5 mm thickness showed the lowest ΔE and TP in both ceramics. Increase in ceramic thickness had a great impact on both color masking ability of the underlying tooth structure and its translucency. The higher the ceramic thickness, the better the masking ability and the lower the translucency was reported.

Piecewise Linier Model Untuk Manajemen Laba: Investigasi Sebelum dan Sesudah Implementasi IFRS pada Perusahaan Manufaktur di Bursa Efek Indonesia

2015 ◽  
Vol 2 (01) ◽  
pp. 97-105
Author(s):  
Rizki Fitrah Ramadhani ◽  
Nurmala Ahmar ◽  
Nuraini Rokhmania
Keyword(s):  
Earnings Management ◽  
Linear Model ◽  
Stock Exchange ◽  
Piecewise Linear ◽  
Financial Statements ◽  
Jel Classification ◽  
Manufacturing Companies ◽  
Piecewise Linear Model ◽  
Before And After ◽  
The Difference

A B S T R A C T This study aimed to examine differences in accrual earnings management by using piecewise linear model of approaching the companies listed on the Indonesian Stock Exchange (BEI) before and after the implementation of IFRS. Samples are 108 manufacturing companies. Year study was conducted during the period 2011 to calculate before the implementation of IFRS and 2013 to calculate after the implementation of IFRS. Criteria in the selection of the research object, among others, the company that serves the complete financial statements, the company does not move the sector, does not cease trading companies, as well as companies that serve the financial statements with the currency. The research proves the difference in accrual earnings management with Piecewise Linear Model approach in 2011 and in 2013. A B S T R A K Penelitian ini bertujuan untuk menguji perbedaan manajemen laba akrual dengan menggunakan model piecewise linear mendekati perusahaan yang terdaftar di Bursa Efek Indonesia (BEI) sebelum dan setelah pelaksanaan IFRS. Sampel adalah 108 perusahaan manufaktur. Tahun penelitian ini dilakukan selama periode 2011 untuk menghitung sebelum pelaksanaan IFRS dan 2013 untuk menghitung setelah pelaksanaan IFRS. Kriteria dalam pemilihan objek penelitian, antara lain, perusahaan yang melayani laporan keuangan yang lengkap, perusahaan tidak bergerak sektor, tidak menghentikan perdagangan perusahaan, serta perusahaan yang melayani laporan keuangan dengan mata uang. Hasil penelitian membuktikan adanya perbedaan manajemen laba akrual dengan Piecewise Linear pendekatan Model pada tahun 2011 dan pada tahun 2013. JEL Classification: G14

Modeling of the Solidification Process—Historical Survey

MRS Bulletin ◽  
1986 ◽  
Vol 11 (5) ◽  
pp. 31-33
Author(s):  
John Âgren
Keyword(s):  
Solidification Rate ◽  
Solidification Process ◽  
Heat Propagation ◽  
Mathematical Treatment ◽  
Historical Survey ◽  
System A ◽  
Different Types ◽  
Solidification Processes ◽  
Cad Cam ◽  
Academy Of Sciences

The modeling of solidification processes is a broad field covering many different types of activities. On one level, technical aspects of casting processes are investigated by computer simulations. The modeling is then a tool for the designer and the calculations may even be integrated with a CAD/CAM system. A more fundamental level may consider how the microstructure develops during solidification and how it can be controlled. This article gives a brief historical survey of the modeling of solidification processes.A well-known rule of thumb, often given in textbooks, states that the solidification time for a simple casting is proportional to its squared volume-to-area ratio. This rule is named after Chovrinov, who verified it experimentally in 1940. The mathematical treatment of solidification, however, has a much older tradition started more than 100 year s earlier in 1831 when Lamé and Clapeyron analyzed the growth of a solid crust generated by cooling a liquid. Their analysis showed that the thickness of the solid is proportional to the square root of time, which is also the essence of Chovrinov's rule. Their basic idea was that the solidification rate was controlled by the removal of latent heat. That idea may seem quite obvious to us, but a necessary pre-equisite for it is the concept of heat as quantifiable and transportable. Actually, Fourier had made his mathematical analysis of heat propagation only 20 years earlier and had won the prize of the French Academy of Sciences in 1811 for his contribution.

A Study on CAD/CAM Application in CNC Milling Using Industrial Clay

2015 ◽  
Vol 761 ◽  
pp. 32-36
Author(s):  
Nurul Wahieda Muhamad Bustaman ◽  
Mohd Salman Abu Mansor
Keyword(s):  
Low Cost ◽  
Machining Parameters ◽  
Milling Machine ◽  
Design Phase ◽  
Cnc Milling ◽  
Clay Sample ◽  
Machining Time ◽  
Cnc Milling Machine ◽  
Cad Cam ◽  
The Difference

Throughout the production process, improper planning and exploitation of the CAD/CAM system leads to the low level utilization of the CNC milling machine. In product design, tangible prototype is fabricated using CAD/CAM techniques in the design phase to analyse and modify the product before actual production. In this research, industrial clay is used as the prototype material. The objectives of the study are to investigate the machining parameters of industrial clay using the CNC milling machine and to apply the CAD/CAM system in producing a clay sample part via the CNC milling machine. Using uncomplicated and low cost setup for the fabrication method, an industrial clay sample part is prepared in the CAD/CAM system and shaped using the CNC milling machine. The difference between the simulated and the actual machining time of the machined part is analysed.

scholarly journals Piecewise Linier Model Untuk Manajemen Laba: Investigasi Sebelum dan Sesudah Implementasi IFRS pada Perusahaan Manufaktur di Bursa Efek Indonesia

2015 ◽  
Vol 2 (01) ◽  
pp. 97-105
Author(s):  
Rizki Fitrah Ramadhani ◽  
Nurmala Ahmar ◽  
Nuraini Rokhmania
Keyword(s):  
Earnings Management ◽  
Linear Model ◽  
Stock Exchange ◽  
Piecewise Linear ◽  
Financial Statements ◽  
Jel Classification ◽  
Manufacturing Companies ◽  
Piecewise Linear Model ◽  
Before And After ◽  
The Difference

A B S T R A C T This study aimed to examine differences in accrual earnings management by using piecewise linear model of approaching the companies listed on the Indonesian Stock Exchange (BEI) before and after the implementation of IFRS. Samples are 108 manufacturing companies. Year study was conducted during the period 2011 to calculate before the implementation of IFRS and 2013 to calculate after the implementation of IFRS. Criteria in the selection of the research object, among others, the company that serves the complete financial statements, the company does not move the sector, does not cease trading companies, as well as companies that serve the financial statements with the currency. The research proves the difference in accrual earnings management with Piecewise Linear Model approach in 2011 and in 2013. A B S T R A K Penelitian ini bertujuan untuk menguji perbedaan manajemen laba akrual dengan menggunakan model piecewise linear mendekati perusahaan yang terdaftar di Bursa Efek Indonesia (BEI) sebelum dan setelah pelaksanaan IFRS. Sampel adalah 108 perusahaan manufaktur. Tahun penelitian ini dilakukan selama periode 2011 untuk menghitung sebelum pelaksanaan IFRS dan 2013 untuk menghitung setelah pelaksanaan IFRS. Kriteria dalam pemilihan objek penelitian, antara lain, perusahaan yang melayani laporan keuangan yang lengkap, perusahaan tidak bergerak sektor, tidak menghentikan perdagangan perusahaan, serta perusahaan yang melayani laporan keuangan dengan mata uang. Hasil penelitian membuktikan adanya perbedaan manajemen laba akrual dengan Piecewise Linear pendekatan Model pada tahun 2011 dan pada tahun 2013. JEL Classification: G14

scholarly journals Clinical Report of Six-Month Follow-Up After Cementing PEEK Crown On Molars

2021 ◽  
Author(s):  
Hitomi Kimura ◽  
Koji Morita ◽  
Fumiko Nishio ◽  
Hiroshi Abekura ◽  
Kazuhiro Tsuga
Keyword(s):  
Patient Satisfaction ◽  
Rank Test ◽  
Prosthetic Material ◽  
Clinical Report ◽  
Occlusal Force ◽  
Significance Level ◽  
Masticatory Ability ◽  
Significant Difference ◽  
Cad Cam ◽  
The Difference

Abstract To investigate the therapeutic effect of polyetheretherketone (PEEK) crowns, a six-month clinical study on CAD/CAM-fabricated molar PEEK crowns was conducted. Twenty-three cases of PEEK crowns placed on the molars of 20 subjects (7 males and 13 females, mean age: 60.6 ± 14.4 years) were included in the study. The evaluation items were the condition of the crowns at the time of cementation and after six months, patient satisfaction, masticatory ability, and occlusal force. A Wilcoxon signed-rank test with a significance level of 5% was used to examine the difference in masticatory ability with and without PEEK crowns. The occlusion, margin fit, and contact of all 23 cases at the time of cementing was good. Six months after cementation, there was no crown desorption, no fracture or crack, and no prosthodontics was needed in the 22 cases where one patient dropped out. No wear of the dental antagonist was observed. Patient satisfaction was generally high. There was no significant difference in masticatory ability between the groups with and without PEEK crowns. The subject's occlusal force was within normal range. PEEK crowns on molars are highly therapeutic methods and can be fully used as a crown prosthetic material to replace metal.

scholarly journals A novel tool for monitoring and assessing the outcome of thermal ablations of hepatic lesions

2021 ◽  
Vol 7 (1) ◽  
pp. 72-75
Author(s):  
Georg Hille ◽  
Felicitas Brokmann ◽  
Bennet Hensen ◽  
Julian Alpers ◽  
Frank Wacker ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Heat Propagation ◽  
Treatment Result ◽  
Proof Of Concept ◽  
Patient Case ◽  
Anatomical Structures ◽  
Hepatic Tumours ◽  
Hepatic Lesions ◽  
Temperature Maps ◽  
2D And 3D

Abstract This paper presents a proof-of-concept intervention monitoring and outcome assessment tool for thermal ablative strategies like microwave ablation of hepatic tumours. For this purpose, simulated 3D+t temperature maps of the ablation progress are combined with liver MR imaging, as well as corresponding segmentations of the lesion and other relevant anatomical structures. The proposed tool mainly consists of a monitoring and validation part, each comprising 2D and 3D visualisations and various modifiable settings. With the aid of the monitoring features, the heat propagation during the ablation progress could be visually tracked, while the validation part of the tool provides the radiologist with comprehensible and detailed feedback to assess the treatment result. Hence, it could enable an immediate validation of the ablation progress and support interventional decision-making. For evaluation purposes, we used an exemplary patient case to demonstrate the benefits of the proposed prototype. This tool could represent a crucial step towards a suitable computerassisted and more accurate workflow of thermal ablations, with benefits for both, patients and radiologists.

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