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Solving a fractional program with second order cone constraint
, Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 14, Issue 2 , 2019 , Pages 33-42 ; 17354463 (ISSN) ; Saraj, M ; Mahdavi Amiri, N ; Sharif University of Technology
Iranian Academic Center for Education, Culture and Research
2019
Abstract
Our main interest in the present article is to consider a fractional program with both linear and quadratic equation in numerator and denominator with second order cone (SOC) constraints. With a suitable change of variable, we transform the problem into a second order cone programming (SOCP) problem. For the quadratic fractional case, using a relaxation, then the problem is reduced to a semi-definite optimization (SDO)) program. The problem is solved with SDO relaxation and the obtained results are compared with the interior point method (IPM), sequential quadratic programming approach (SQP), active set, genetic algorithm. It is observe that the SDO relaxation method is much more accurate...
Solving a fractional program with second order cone constraint
, Article Iranian Journal of Mathematical Sciences and Informatics ; Volume 14, Issue 2 , 2019 , Pages 33-42 ; 17354463 (ISSN) ; Saraj, M ; Mahdavi Amiri, N ; Sharif University of Technology
Iranian Academic Center for Education, Culture and Research
2019
Abstract
Our main interest in the present article is to consider a fractional program with both linear and quadratic equation in numerator and denominator with second order cone (SOC) constraints. With a suitable change of variable, we transform the problem into a second order cone programming (SOCP) problem. For the quadratic fractional case, using a relaxation, then the problem is reduced to a semi-definite optimization (SDO)) program. The problem is solved with SDO relaxation and the obtained results are compared with the interior point method (IPM), sequential quadratic programming approach (SQP), active set, genetic algorithm. It is observe that the SDO relaxation method is much more accurate...
Investigation of Water Coning Phenomenon and its Effective Parameters in a Fractured Reservoir
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor) ; Ghazanfari, Mohammad Hossein (Co-Advisor)
Abstract
Water coning is a complex phenomenon that depends on various parameters which include among: production rate, matrix and fracture permeability, perforation interval, aquifer size, mobility ratio, capillary pressure, etc. Production of water can greatly affect the productivity of a well and the reservoir at large volume. In naturally fractured reservoirs, this problem is more complex because permeability of the fractures in the porous media is too high. With this complexity of water coning behavior in naturally fractured reservoir, this phenomenon was studied by simulating a sector of a carbonate fractured reservoir supported by an aquifer using Eclipse-300 simulator. A sector of an Iranian...
Efficient solutions of interval programming problems with inexact parameters and second order cone constraints
, Article Mathematics ; Volume 6, Issue 11 , 2018 ; 22277390 (ISSN) ; Saraj, M ; Mahdavi Amiri, N ; Sharif University of Technology
MDPI AG
2018
Abstract
In this article, a methodology is developed to solve an interval and a fractional interval programming problem by converting into a non-interval form for second order cone constraints, with the objective function and constraints being interval valued functions. We investigate the parametric and non-parametric forms of the interval valued functions along with their convexity properties. Two approaches are developed to obtain efficient and properly efficient solutions. Furthermore, the efficient solutions or Pareto optimal solutions of fractional and non-fractional programming problems over R + n S (0) are also discussed. The main idea of the present article is to introduce a new concept for...
Tilted-Lorentz symmetry
, Article Iranian Journal of Physics Research ; Volume 19, Issue 4 , Winter , 2020 , Pages 831-834 ; Sharif University of Technology
Isfahan University of Technology
2020
Abstract
Dirac cone can be tilted in condensed matter setting. As a result of tilt, the Lorentz symmetry is reduced to what we call tilted-Lorentz symmetry. In this paper, we derive the tilted-Lorentz transformations that leave a world with tilted Dirac cone invariant. © 2020, Isfahan University of Technology. All rights reserved
A constitutive model for finite deformation of endochronic plasticity in powder forming processes
, Article Journal of Materials Processing Technology ; Volume 153-154, Issue 1-3 , 2004 , Pages 12-19 ; 09240136 (ISSN) ; Bakhshiani, A ; Sharif University of Technology
2004
Abstract
In this paper, an endochronic constitutive model is developed for cold powder compaction processes. As large deformations are observed in powder forming processes, the endochronic constitutive model based on large strain plasticity is presented and an integration scheme for the rate constitutive equations is established. Although the concept of yield surface has not been explicitly assumed in the endochronic theory, it is demonstrated that the cone-cap yield surface can be derived as a special case of the proposed endochronic model. The plastic flow rule and the dilatancy condition of the model are derived and a procedure for calibration of material parameters of the constitutive model is...
Cone penetration test in sand: anumerical-analytical approach
, Article Computers and Geotechnics ; Volume 90 , 2017 , Pages 176-189 ; 0266352X (ISSN) ; Golestani Dariani, A. A ; Sharif University of Technology
Abstract
Separation of the effects of initial horizontal stress and relative density on cone tip resistance in sandy soils has been a complicated issue for many years. In order to overcome this problem, a numerical modeling of CPT which has been verified by calibration chamber tests, has been used in this paper to achieve a reliable analytical solution. The analytical solution has resulted in two relationships for sleeve friction and cone tip resistance in terms of the initial conditions of sandy soil. Based on the presented solution, the initial horizontal stress and relative density can be determined according to CPT measurements. © 2017 Elsevier Ltd
A numerical study of chamber size and boundary effects on CPT tip resistance in NC sand
, Article Scientia Iranica ; Volume 15, Issue 5 , 2008 , Pages 541-553 ; 10263098 (ISSN) ; Robertson, P. K ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
A numerical modeling procedure was used to quantify calibration chamber size and boundary effects for cone penetration testing in sand. In the numerical analyses, chamber diameter and boundary conditions were varied to investigate the effects of chamber size and boundary conditions on cone tip resistance. These analyses show that, for loose sand, a chamber-to-cone diameter ratio of 33 is sufficient for the boundaries to have no influence on the cone tip measurements. However, for very dense sand, the numerical analyses show that the chamber-to-cone diameter ratio should be more than 100 to ensure that boundaries have no influence on cone tip measurements. Numerical analysis indicates that,...
Thermal Local Buckling of Metal Truncated Conical Shells with Composite Rainforced Layers by Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
In this study, the thermal buckling behavior of thin metal liner reinforced by composite shell in present of the initial imperfection is investigated. For this purpose, the Ryzener – Myndlyn shear-deformation theory & the virtual work method are used to extract equilibrium equations. In this work, the conical shell with c-c, s-s, c-f boundary conditions has been studied. The outer layer of reinforced composite is exposed to constant ambient temperature and iner layer is exposed to heat. Metal liner and reinforced composite shell are merged with together. In other words, the degrees of freedom at each node for both shells are assumed to be equal. Solution method is finite element method using...
Poncelet Theorem
, M.Sc. Thesis Sharif University of Technology ; Jafari, Amir (Supervisor)
Abstract
In this thesis the theorems of Poncelet and Cayley will be discussed. We will use algebraic geometry and in particular the theory of elliptic curves to present a proof following the works of Griffiths and Harris (refrence 1).
The P2-version of poncelet’s theorem that we prove in our thesis says:let C , D be smooth conic in general position. Suppose there is an n-sided olygon inscribed in C and circumscribed about D.Then for any point of C, there exists an n-sided polygen, also inscribed in C and circumscribe about D, which has this point for one of its vertics.the Cayley’s theorem provides a criterion on the existence of such an n-gon given the conics C and D as above
The P2-version of poncelet’s theorem that we prove in our thesis says:let C , D be smooth conic in general position. Suppose there is an n-sided olygon inscribed in C and circumscribed about D.Then for any point of C, there exists an n-sided polygen, also inscribed in C and circumscribe about D, which has this point for one of its vertics.the Cayley’s theorem provides a criterion on the existence of such an n-gon given the conics C and D as above
New complexity analysis of a full Nesterov-Todd step infeasible interior-point algorithm for symmetric optimization
, Article Kybernetika ; Volume 49, Issue 6 , 2013 , Pages 883-896 ; 00235954 (ISSN) ; Mahdavi Amiri, N ; Sharif University of Technology
2013
Abstract
A full Nesterov-Todd step infeasible interior-point algorithm is proposed for solving linear programming problems over symmetric cones by using the Euclidean Jordan algebra. Using a new approach, we also provide a search direction and show that the iteration bound coincides with the best known bound for infeasible interior-point methods
An improved infeasible interior-point method for symmetric cone linear complementarity problem
, Article Bulletin of the Iranian Mathematical Society ; Volume 42, Issue 7 Special Issue , 2016 , Pages 55-66 ; 10186301 (ISSN) ; Mahdavi Amiri, N ; Sharif University of Technology
Iranian Mathematical Society
Abstract
In the earlier version, each iteration consisted of one so-called feasibility step and a few -at most three-centering steps. Here, each iteration consists of only a feasibility step. Thus, the new algorithm demands less work in each iteration and admits a simple analysis of complexity bound. The complexity result coincides with the best-known iteration bound for infeasible interior-point methods
Investigation of fire growth and spread in a model-scale railcar using an applied approach
, Article Journal of Applied Fluid Mechanics ; Volume 9, Issue 1 , 2016 , Pages 279-292 ; 17353572 (ISSN) ; Pourghasemi, M ; Afshin, H ; Farhanieh, B ; Sharif University of Technology
Isfahan University of Technology
Abstract
Fire is a potential hazard in public transportation facilities such as subways or road tunnels due to its contribution to high number of deaths. To provide an insight into fire development behavior in tunnels which can serve as the basis for emergency ventilation design, model-scale railcar fire is explored numerically in this research. Fire growth and its spread are investigated by analyzing the HRR curve as the representative of fire behavior in different stages. Fire development has been predicted through a new approach using an Arrhenius-based pyrolysis model, established to predict the decomposition behavior of solid flammable materials exposed to heat flux. Using this approach,...
A wide neighborhood primal-dual predictor-corrector interior-point method for symmetric cone optimization
, Article Numerical Algorithms ; 2017 , Pages 1-18 ; 10171398 (ISSN) ; Mansouri, H ; Zangiabadi, M ; Mahdavi Amiri, N ; Sharif University of Technology
Abstract
We present a primal-dual predictor-corrector interior-point method for symmetric cone optimization. The proposed algorithm is based on the Nesterov-Todd search directions and a wide neighborhood, which is an even wider neighborhood than a given negative infinity neighborhood. At each iteration, the method computes two corrector directions in addition to the Ai and Zhang directions (SIAM J. Optim. 16, 400–417, 2005), in order to improve performance. Moreover, we derive the complexity bound of the wide neighborhood predictor-corrector interior-point method for symmetric cone optimization that coincides with the currently best known theoretical complexity bounds for the short step algorithm....
A wide neighborhood primal-dual predictor-corrector interior-point method for symmetric cone optimization
, Article Numerical Algorithms ; Volume 78, Issue 2 , 2018 , Pages 535-552 ; 10171398 (ISSN) ; Mansouri, H ; Zangiabadi, M ; Mahdavi Amiri, N ; Sharif University of Technology
Springer New York LLC
2018
Abstract
We present a primal-dual predictor-corrector interior-point method for symmetric cone optimization. The proposed algorithm is based on the Nesterov-Todd search directions and a wide neighborhood, which is an even wider neighborhood than a given negative infinity neighborhood. At each iteration, the method computes two corrector directions in addition to the Ai and Zhang directions (SIAM J. Optim. 16, 400–417, 2005), in order to improve performance. Moreover, we derive the complexity bound of the wide neighborhood predictor-corrector interior-point method for symmetric cone optimization that coincides with the currently best known theoretical complexity bounds for the short step algorithm....
Stochastic analysis of micro-cone penetration tests in snow
, Article Cryosphere ; Volume 16, Issue 12 , 2022 , Pages 4811-4822 ; 19940416 (ISSN) ; Peinke, I ; Hagenmuller, P ; Wächter, M ; Rahimi Tabar, M. R ; Peinke, J ; Sharif University of Technology
Copernicus Publications
2022
Abstract
Cone penetration tests have long been used to characterize snowpack stratigraphy. With the development of sophisticated digital penetrometers such as the SnowMicroPen, vertical profiles of snow hardness can now be measured at a spatial resolution of a few micrometers. By using small penetrometer tips at this high vertical resolution, further details of the penetration process are resolved, leading to many more stochastic signals. An accurate interpretation of these signals regarding snow characteristics requires advanced data analysis. Here, the failure of ice connections and the pushing aside of separated snow grains during cone penetration lead to a combination of (a) diffusive noise, as...
Full Nesterov-Todd step feasible interior-point algorithm for symmetric cone horizontal linear complementarity problem based on a positive-asymptotic barrier function
, Article Optimization Methods and Software ; 2020 ; Mahdavi Amiri, N ; Darvay, Z ; Rigó, P .R ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
We present a feasible full step interior-point algorithm to solve the (Formula presented.) horizontal linear complementarity problem defined on a Cartesian product of symmetric cones, which is not based on a usual barrier function. The full steps are scaled utilizing the Nesterov-Todd (NT) scaling point. Our approach generates the search directions leading to the full-NT steps by algebraically transforming the centring equation of the system which defines the central trajectory using the induced barrier of a so-called positive-asymptotic kernel function. We establish the global convergence as well as a local quadratic rate of convergence of our proposed method. Finally, we demonstrate that...
An investigation on perpetual asphalt pavements in Minnesota
, Article International Journal of Pavement Research and Technology ; Volume 13, Issue 3 , 2020 , Pages 247-254 ; Sharif University of Technology
Springer
2020
Abstract
Asphalt Pavement Alliance (APA) created the Perpetual Pavement Award program in 2001. This program requires that the roadway has at least 35 years of service at the time of award and had experienced no structural failures. In addition, the program limits candidate roadways to those that have not received more than 100 mm of new asphalt nor have been resurfaced at a frequency exceeding 13 years. Minnesota Department of Transportation (MnDOT) currently owns the record for the most award winners and has received an award every year from 2002 through 2017. This study reviews all the award-winning roadways in Minnesota to determine common material, design factors and considerations which may have...
Cone tip resistance in sand: Modeling, verification, and applications
, Article Canadian Geotechnical Journal ; Volume 42, Issue 4 , 2005 , Pages 977-993 ; 00083674 (ISSN) ; Bryne, P. M ; Campanella, R. G ; Sharif University of Technology
2005
Abstract
A numerical modeling procedure is presented to evaluate cone tip resistance in sand. The procedure involves a moving boundary simulating cone penetration. The soil is modeled as a Mohr-Coulomb elastic-plastic material with stress-dependent parameters. The procedure is verified by comparing predicted numerical values of cone tip resistance with published experimental measurements from calibration chamber tests. The selected database. consists of 59 calibration chamber tests on Ticino sand with different relative densities, overconsolidation ratios, stresses, and boundary conditions. Several applications of the modeling procedure are also presented. The computer program FLAC is used to carry...
Full Nesterov-Todd step feasible interior-point algorithm for symmetric cone horizontal linear complementarity problem based on a positive-asymptotic barrier function
, Article Optimization Methods and Software ; Volume 37, Issue 1 , 2022 , Pages 192-213 ; 10556788 (ISSN) ; Mahdavi Amiri, N ; Darvay, Z ; Rigó, P.R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
We present a feasible full step interior-point algorithm to solve the (Formula presented.) horizontal linear complementarity problem defined on a Cartesian product of symmetric cones, which is not based on a usual barrier function. The full steps are scaled utilizing the Nesterov-Todd (NT) scaling point. Our approach generates the search directions leading to the full-NT steps by algebraically transforming the centring equation of the system which defines the central trajectory using the induced barrier of a so-called positive-asymptotic kernel function. We establish the global convergence as well as a local quadratic rate of convergence of our proposed method. Finally, we demonstrate that...