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Developing an algorithm for reconstruction blocky systems in discontinuous media: three-dimensional analysis

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 2013年第7期37卷 661-684页

作者： Jafari, A. Khishvand, M. Rahami, H. Univ Tehran Univ Coll Engn Tehran Iran

Block detection is one of the important steps in all discontinuous methods of analysis such as discontinuous deformation analysis and discrete element method. It is in fact a pre-processing step for these methods. This paper describes a new approach to the problem of geometrically defining polyhedral rock blocks created by the intersection of planar discontinuities in a rock mass. An approach is developed based on the concept of using matrices with integer elements that mostly represent vertices, edges, or face numbers and their connections. Using square matrices with integer elements and performing edge/face regularization reduce the size of the matrices because of elimination of unnecessary faces, edges, and vertices;speed and accuracy of block tracing operation will be increased. This algorithm is able to trace and identify all kinds of blocks including convex and concave blocks formed by limited or unlimited fractures. The simplicity of the procedure makes it very attractive. The algorithm was programmed in C#.Net by over 8100 code lines;several examples are presented to show application of the algorithm in different situations. Copyright (c) 2011 John Wiley & Sons, Ltd.

关键词： rock block tracing block detection computational algorithm matrix-based method 3D-DDA DEM

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Simulated bone remodeling around tilted dental implants in the anterior maxilla

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BIOMECHANICS AND MODELING IN MECHANOBIOLOGY 2016年第3期15卷 701-712页

作者： Wang, Chao Zhang, Weiping Ajmera, Deepal Haresh Zhang, Yun Fan, Yubo Ji, Ping Chongqing Med Univ Stomatol Hosp Coll Stomatol 426 Songshi North Rd Chongqing 401147 Peoples R China Chongqing Key Lab Oral Dis & Biomed Sci Chongqing Peoples R China Lanzhou Hosp Stomatol Lanzhou Peoples R China Beihang Univ Sch Biol Sci & Med Engn Lab Biomech & Mechanobiol Minist Educ 37 Xueyuan Rd Beijing 100191 Peoples R China

Dental implants have to be placed with the long axis in different angulations due to the change in bone morphology. The objective of this study was to investigate the different bone remodeling response induced by the tilted dental implants and to assess whether it could lead to bone loss and implant failure. In this study, bone remodeling due to palato-labially inclined dental implants placed in the anterior maxillary incisor region was simulated. CT-based finite element models of a maxillary bone with dental implants were created herein. Five dental implants were placed at , , , and , respectively. The remodeling progression was recorded and compared. Model (palatal side) shows the highest bone density values, but the inclined implant at (labial side) leads to significant bone loss. From a biomechanical perspective, it is speculated that a palatally inclined implant is more likely to enhance the bone density in the maxillary anterior region, but labial inclination of implant could jeopardize its stability.

关键词： Implant inclination Bone remodeling simulation Maxillary bone Finite element analysis computational algorithm

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Completely conservative and oscillationless semi-Lagrangian schemes for advection transportation

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JOURNAL OF computational PHYSICS 2001年第2期170卷 498-522页

作者： Xiao, F Yabe, T Tokyo Inst Technol Dept Energy Sci Midori Ku Yokohama Kanagawa 2268502 Japan Tokyo Inst Technol Dept Mech Engn & Sci Meguro Ku Tokyo 1528552 Japan SEAVANS N Frontier Res Syst Global Change Minato Ku Tokyo 1056791 Japan

In this paper, we present a new type of semi-Lagrangian scheme for advection transportation equation. The interpolation function is based on a cubic polynomial and is constructed under the constraints of conservation of cell-integrated average and the slope modification. The cell-integrated average is defined via the spatial integration of the interpolation function over a single grid cell and is advanced using a flux form. Nonoscillatory interpolation is constructed by choosing proper approximation to the cell-center values of the first derivative of the interpolation function. which appears to be a free parameter in the present formulation. The resulting scheme is exactly conservative regarding the cell average of the advected quantity and does not produce any spurious oscillation. Oscillationless solutions to linear transportation problems were obtained. Incorporated with an entropy-enforcing numerical nux, the presented schemes can accurately compute shocks and sonic rarefaction waves when applied to nonlinear problems. (C) 2001 Academic Press.

关键词： atmospheric modeling computational algorithm semi-Lagrangian scheme linear and nonlinear transportation equations mass conservation shock wave

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Efficient computation of Laguerre polynomials

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COMPUTER PHYSICS COMMUNICATIONS 2017年 210卷 124-131页

作者： Gil, Amparo Segura, Javier Temme, Nico M. Univ Cantabria Dept Matemat Aplicada & Ciencias Comput E-39005 Santander Spain Univ Cantabria Dept Matemat Estadist & Comput E-39005 Santander Spain San Diego State Univ Dept Math & Stat 5500 Campanile Dr San Diego CA 92182 USA IAA NL-1825 BD Alkmaar 25 Netherlands CWI NL-1098 XG Amsterdam Netherlands

An efficient algorithm and a Fortran 90 module (LaguerrePol) for computing Laguerre polynomials L-n((alpha)) (z) are presented. The standard three-term recurrence relation satisfied by the polynomials and different types of asymptotic expansions valid for n large and a small, are used depending on the parameter region. Based on tests of contiguous relations in the parameter a and the degree n satisfied by the polynomials, we claim that a relative accuracy close to or better than 10(-12) can be obtained using the module LaguerrePol for computing the functions L-n((a))(z) in the parameter range z >= 0,-1 < alpha <= 5, n >= 0. Program summary Program Title: Module LaguerrePol Program Files doi: http://***/10.17632/3jkk659cn8.1 Licensing provisions: CC by 4.0 Programming language: Fortran 90 Nature of problem: Laguerre polynomials L-n((a))(z) appear in a vast number of applications in physics, such as quantum mechanics, plasma physics, etc. Solution method: The algorithm uses asymptotic expansions or recurrence relations for computing the function values depending on the range of parameters. Restrictions: The admissible input parameter ranges for computing the Laguerre L-n((a))(z) are z >= 0, -1 < alpha <= 5, n >= 0. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Laguerre polynomials computational algorithm Asymptotic expansions Recurrence relations

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Coupled elastoplasticity and plastic strain-induced phase transformation under high pressure and large strains: Formulation and application to BN sample compressed in a diamond anvil cell

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INTERNATIONAL JOURNAL OF PLASTICITY 2017年 96卷 156-181页

作者： Feng, Biao Levitas, Valery I. Iowa State Univ Dept Aerosp Engn Ames IA 50011 USA Los Alamos Natl Lab Los Alamos NM 87545 USA Iowa State Univ Dept Aerosp Engn Ames IA 50011 USA Iowa State Univ Dept Mech Engn Ames IA 50011 USA Iowa State Univ Dept Mat Sci & Engn Ames IA 50011 USA Ames Lab Div Mat Sci & Engn Ames IA 50011 USA

In order to study high-pressure phase transformations (PTs), high static pressure is produced by compressing a thin sample within a high strength gasket in a diamond anvil cell (DAC). However, since a PT occurs during plastic flow, it is classified and treated here as a plastic strain-induced PT. A thermodynamically consistent system of equations for combined plastic flow and plastic strain-induced PTs is formulated for large elastic, plastic, and transformation strains. The Murnaghan elasticity law, pressure-dependent J(2) plasticity (both dependent of the concentration of a high-pressure phase), and plastic strain-induced and pressure-dependent PT kinetics are utilized. A computational algorithm within finite element method (FEM) is presented and implemented in a user material subroutine (UMAT) in the FEM code ABAQUS. Combined plastic flow and strain-induced PT from the highly disordered hexagonal boron nitride (hBN) sample to a superhard wurtzitic wBN is simulated within the rhenium gasket for pressures up to 50 GPa. The evolution of the fields of stresses and plastic strains, as well as the concentration of phases in a sample is obtained and discussed in detail. Stress-strain fields in a gasket and diamond are presented as well. An unexpected shape of the deformed sample with almost complete PT in the external part of the sample that penetrated the gasket was found. Obtained results demonstrated the difference between material and system behavior which are often confused by experimentalists. Thus, while plastic strain-induced PT may start (and end) at plastic straining slightly above 6.7 GPa, it is not visible below 12 GPa. It becomes detectable at 21 GPa and is not completed everywhere in a sample even at a maximum pressure of 50 GPa. Due to a strong gasket the gradient of pressure is much smaller than the gradient of plastic strain, and therefore the distribution of the high pressure phase is mostly determined by the plastic strain field instead of the pressur

关键词： Large deformation Plasticity Plastic strain-induced phase transformation High pressure Diamond anvil cell computational algorithm

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BRING THE NOISE: Embracing Randomness Is the Key to Scaling Up Machine Learning algorithms

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BIG DATA 2013年第2期1卷 110-112页

作者： Dalessandro, Brian Media6degrees M6D Data Sci 37 East 18 St9th Floor New York NY USA

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Systematic approach to MUSIC estimation with minimisation of its cost function

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ELECTRONICS LETTERS 1999年第8期35卷 620-621页

作者： Choi, YH Dongyang Univ Sch Informat & Commun Engn Kyungbook 750711 South Korea

Based on the minimisation of a cost function, a systematic approach to MUSIC estimation is proposed for the arrival angles of the signals impinging on a sensor array. The proposed method, which employs Brent's method for the task together with bisection bracketing, can significantly reduce the computational burden compared to the conventional algorithm for computing the whole spatial spectrum.

关键词： signal arrival angle minimisation computational algorithm array signal processing Optimisation techniques multiple signal characterisation sensor array spatial spectrum MUSIC estimation Signal processing and detection direction-of-arrival estimation Brent method cost function minimisation bisection bracketing

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Why doesn't everyone use it?

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JOURNAL OF CLINICAL LASER MEDICINE & SURGERY 2003年第6期21卷 335-336页

作者： Lanzafame, RJ

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Mutual verification of two new quantum simulation approaches for nanomagnets

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PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES 2014年 62卷 123-127页

作者： Liu, Z. -S. Sechovsky, V. Divis, M. Nanjing Univ Informat Sci & Technol Dept Appl Phys Nanjing 210044 Jiangsu Peoples R China Charles Univ Prague Dept Condensed Matter Phys Fac Math & Phys Prague 12116 2 Czech Republic

Two new quantum simulation methods, which we developed recently based on the Metropolis and self-consistent algorithms defined as QMC and SCA approaches respectively, were employed to investigate the magnetic properties of an antiferromagnetic nanoparticle with strong surface anisotropy. All simulations were started from a random magnetic configuration and carried out from a temperature well above the phase transition stepwise down to very low temperatures as other researchers have been doing in classical Monte Carlo (CMC) simulations. It turns out that the magnetic structures, magnetizations, total (free) energy, magnetic entropy and specific heat calculated by means of the two approaches are well consistent with each other, thereby verifying their correctness mutually. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Quantum simulation model computational algorithm Magnetic structure Nanomagnet

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Compuational algorithm of Fuzzy Stochastic Model for Forecasting

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JOURNAL OF algorithmS & computational TECHNOLOGY 2012年第3期6卷 375-383页

作者： Arumugam, P. Kannan, Senthamarai K. Manonmaniam Sundaranar Univ Tirunelveli Dept Stat Tirunelveli India

In our daily life, often we use forecasting techniques to predict weather, economy, population growth, stock, etc. In recent years, many fuzzy time series methods are developed for forecasting of enrollments of Universities. Song and Chissom (1993) were the pioneers in studying such type of problems. Shiva Raj Sing (2007) presented a simple time variant method for forecasting the enrollment of the University of Alabama using fuzzy time series. Forecasts are needed only if there is uncertainty about the future. In this paper develop the modified algorithm to forecast enrollment for the same data set and compared with existing methods. The proposed method shows the better forecasting accuracy rate for enrollments, compared than other methods.

关键词： computational algorithm Fuzzy logical relationship Fuzzy time series Forecasting and Mean Square Error

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