42 results
Search Results
2. Calculation results for optimization of underground structures.
- Author
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Yakubov, Sabir, Khushbokov, Ismoil, and Saidakhmedov, Eldor
- Subjects
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UNDERGROUND construction , *PROBLEM solving , *MATHEMATICAL models - Abstract
The paper examines optimization problems for underground structures based on algorithmic methods, develops mathematical models, and specifies algorithms for solving them. Solving these problems allowed us to achieve significant savings in materials and costs compared to existing projects. The possibility of designing vault structures with minimal consumption of materials is being explored. The results of calculations for the optimization of underground structures are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Simulation on correlation of pulse ignition sensitivity for hot bridge wire EED.
- Author
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Lyu, Xuxu, Wei, Guanghui, Song, Mingchang, Sun, Jiangning, Zhao, Hongze, and Lu, Xinfu
- Subjects
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CRITICAL currents , *ELECTROMAGNETIC pulses , *ELECTROMAGNETIC radiation , *PROBLEM solving , *MATHEMATICAL models - Abstract
To solve the problem of testing the sensitivity under electromagnetic pulse radiation for a hot bridge wire electro-explosive device (EED), this paper simulated and analyzed the correlation between the critical ignition current under steady and pulse excitation. The simulation results showed that, under single pulse excitation, the critical ignition current of the EED decreases with the increase in the pulse width, and the variation law can be divided into three pieces: adiabatic, transition, and constant; while under pulse train excitation, due to the thermal cumulative effect, the critical ignition current is related to both material properties and excitation parameters. By analyzing the simulation results and considering the thermal ignition theory, the mathematical model of the critical ignition current under pulse excitation was established, and the mathematical model showed that under pulse train excitation, the critical ignition current is relevant not only to the single pulse excitation critical ignition current, pulse period, and duty cycle, but also to the ratio of single pulse and steady excitation critical ignition current and the thermal time constant. It was verified that the errors between the theoretical values obtained from the mathematical model and the results obtained from the simulation were within 2.5%. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Neutrosophic Bezier model in spline curve.
- Author
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Mahmud, Maziah, Wahab, Abd. Fatah, and Zulkifly, Mohammad Izat Emir
- Subjects
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GENERATING functions , *SPLINES , *MATHEMATICAL models , *PROBLEM solving - Abstract
It is difficult to deal with the uncertainty data issue which has incompleteness, impreciseness and incertitude. Normally, uncertain and vague information is confronted in form of data point. Various mathematical models were developed to resolve issues concerning uncertainty point. In this paper, Neutrosophic Bézier Curve model will be introduced. A mathematical model with a redefinition of the control points that is characterized by three important components of neutrosophic set is designed to solve this problem. These control points are blended with the Bézier basic functions to generate multiple models in the form of neutrosophic spline curve and surface. Then, the related data can be translated through the construction of those models with the neutrosophic concept and its relationships. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. The mathematical modeling skills of eighth-grade students in solving contextual problems.
- Author
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Rahmi, Khalida, Herman, Tatang, and Novianingsih, Khusnul
- Subjects
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PROBLEM solving , *MATHEMATICAL models , *WORD problems (Mathematics) , *QUALITATIVE research - Abstract
Problem-solving using mathematics in various aspects of daily life encourages the importance of mathematical modeling skills. Mathematical modeling holds a crucial role, particularly when solving real-world or contextual problems, as it bridges the extra-mathematical world and the mathematical world. This paper discusses a study on the mathematical modeling skills of eighth-graders in solving contextual problems. This study aimed to investigate the mathematical modeling competency level achievement of the students. This study used the qualitative research method with a case study approach, consisting of five major stages: design, preparation, data collection, data analysis, and reporting. In the design stage, we determined the research focus, and in the preparation stage, we developed research instruments. We collected data by giving tests to 24 participants. After we analyzed the data, we reviewed and rearranged all of the research stages. The results showed that, out of six levels of mathematical modeling competency, which includes level 0 to level 5, most students only achieved level 3. Therefore, we conclude that the students are not yet capable of carrying out all aspects of the mathematical modeling processes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
6. Solution of a contact problem for body with two-piece coating using software Salome-Meca.
- Author
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Maksimova, E. A., Cherednichenko, A. V., and Savelyeva, I. Yu.
- Subjects
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SURFACE coatings , *INTEGRATED software , *EDIBLE coatings , *PROBLEM solving , *COMPUTER software , *MATHEMATICAL models - Abstract
The paper deals with the study of a frictionless contact problem of pressing a rigid hollow cylinder into a deformable cylindrical body with a coating on the upper base. The coating consists of two materials with different characteristics. Geometry and mesh are built according to a simplified mathematical model. Particular attention is paid to solving the problem using the AsterStudy module of Salome-Meca software package. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Solutions of vibration problems of structural-inhomogeneous shell structures by the Müller's method.
- Author
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Salimov, Sh. M., Mavlanov, T., and Numonov, A.
- Subjects
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MATHEMATICAL models , *FUNCTIONAL equations , *COMPLEX variables , *PROBLEM solving , *NONLINEAR equations - Abstract
The development of a unified approach to solving the problems of the dynamics and interaction of multiply connected structurally-inhomogeneous shell structures, which are an arbitrary composition of multilayer shells of revolution and rings, the creation and implementation of an appropriate software package with a high level of automation of all stages of calculations oriented to computer use significantly increase the design efficiency and are a major scientific problem of great economic importance. This paper is dedicated to solving this problem. The study and prediction of the deformation properties of the materials studied in the work are possible based on mathematical modeling of deformation and relaxation processes. In this article, we give an algorithm for solving a nonlinear functional equation with complex variables resulting from mathematical modeling of problems concerning the properties of a deformable solid. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
8. Fuzzy cognitive logic models for diagnostics and predictive evaluation of the health of electromechanical systems.
- Author
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Borisov, V. V., Denisov, V. N., Kurilin, S. P., Luferov, V. S., Gorkunov, Eduard, Panin, Victor E, and Irschik, Hans
- Subjects
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VECTOR spaces , *PREDICTION models , *MATHEMATICAL models , *PROBLEM solving , *MAINTENANCE , *FUZZY logic - Abstract
The paper discusses an approach to the maintenance diagnostics and predictive evaluation of the operational health of electromechanical systems (EMS). It presents a mathematical model of an EMS, which is intended for problems of diagnosing an individual EMS and an EMS operation mode group, offers information on the EMS vector spaces, and describes the general methodology for vector space testing. To solve problems of the maintenance diagnostics and predictive evaluation of EMS health, it is proposed to use hybrid models based on a combination of the fuzzy cognitive approach and the fuzzy logic one. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
9. Problem Solving Process for Heat and Mass Transfer Modeling.
- Author
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Rajarajeswari, Perepi and Ravikumar, M.
- Subjects
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MASS transfer , *HEAT transfer , *PROBLEM solving , *MATHEMATICAL models , *MATHEMATICAL analysis - Abstract
Normally in engineering, conceptual models provide formal model of the system. Mathematical modeling gives the systematic representation in terms of properties. Modeling process is performed by using design space analysis and mathematical equations and this can be performed with different design alternatives. Conceptual analysis of natural convection is described. In this paper the modeling of heat and mass transfer is performed with the concepts of heat and mass transfer and properties of objects in the design space. Numerical solution has been conducted for energy equation with different boundary conditions. The present work analyses the heat and mass transfer modeling process with mathematical equations. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Risk Assessment and Route Optimization for Life and Health Self-Keeping During e-Cycling.
- Author
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Baeva, Silvia, Shterev, Vasil, Stoimenov, Eltimir, and Hinov, Nikolay
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ELECTRIC bicycles , *RISK assessment , *SPACETIME , *MATHEMATICAL models , *DATABASES , *PROBLEM solving - Abstract
The paper presents the creation of a general mathematical model of a two-step optimization problem which finds the most-safer route of an electric-bicycle cyclist. The first step is a multi-criteria problem which finds the average risk in the different segments which forms the complete route. To solve the problem, a scalarization method is used (also known as weighted sum method). In the second step, the safer route is found by applying a network optimization model. To find the solution a method for dynamic optimization is applied (Bellman's Principle). The generation of data is based on the a priori known information as well as on information which is periodic and stochastic in the time and space. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
11. Optimization technique of the equipment parameters for the repair and formation of wheelsets.
- Author
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Bogdanov, Anatoliy, Vorobyov, Aleksandr, Budyukin, Aleksey, and Kondratenko, Vladimir
- Subjects
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MATHEMATICAL optimization , *REPAIRING , *CUTTING tools , *PROBLEM solving , *SHOPPING equipment , *MACHINE tools , *LATHES , *MATHEMATICAL models - Abstract
The performed studies are aimed at the increase of the capacity of operating and prospective wheel shops by means of intensification of the use of existing equipment and creation of new specialized high-performance equipment for the repair and formation of wheelsets. To solve this problem, a technique is developed for the optimization of the parameters of equipment for wheel shops, including a mathematical model with a number of technical and technological limitations. The minimum value of the reduced costs is taken as the optimization criterion. As a result of the performed calculations, the optimal cutting conditions are obtained for the processing of carriage and locomotive axles from forgings and cross rolling products, taking into account the prospects for the development of cutting tools and the achievements of domestic and foreign machine tools. Based on the optimal ranges of changes in the rotation frequency of the principal movement and feed drive systems, and a number of other parameters of the tools, obtained as a result of calculations, the adjustments were made to the processing schemes and diagrammatic works of both existing and prospective machine tools of the enterprises wheel shops. A technical assignment is developed for the design and manufacture of a special multi-cutting semi-automatic lathe with two tool heads for axes. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Profile of Male-Field Dependent (FD) Prospective Teacher's Reflective Thinking in Solving Contextual Mathematical Problem.
- Author
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S., Agustan, Juniati, Dwi, and Siswono, Tatag Yuli Eko
- Subjects
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FIELD dependence (Psychology) , *TEACHER education , *CRITICAL thinking , *PROBLEM solving , *MATHEMATICAL models - Abstract
Reflective thinking is an important component in the world of education, especially in professional education of teachers. In learning mathematics, reflective thinking is one way to solve mathematical problem because it can improve student's curiosity when student faces a mathematical problem. Reflective thinking is also a future competence that should be taught to students to face the challenges and to respond of demands of the 21st century. There are many factors which give impact toward the student's reflective thinking when student solves mathematical problem. One of them is cognitive style. For this reason, reflective thinking and cognitive style are important things in solving contextual mathematical problem. This research paper describes aspect of reflective thinking in solving contextual mathematical problem involved solution by using some mathematical concept, namely linear program, algebra arithmetic operation, and linear equations of two variables. The participant, in this research paper, is a male-prospective teacher who has Field Dependent. The purpose of this paper is to describe aspect of prospective teachers' reflective thinking in solving contextual mathematical problem. This research paper is a descriptive by using qualitative approach. To analyze the data, the researchers focus in four main categories which describe prospective teacher's activities using reflective thinking, namely; (a) formulation and synthesis of experience, (b) orderliness of experience, (c) evaluating the experience and (d) testing the selected solution based on the experience. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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13. Macroelement Analysis of Thin Orthotropic Polygonal Plate Resting on the Elastic Winkler’s Foundation.
- Author
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Delyavskyy, Mykhaylo, Rosiński, Krystian, Zdolbicka, Nina, and Bilash, Oksana
- Subjects
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POLYGONS , *ELASTIC foundations , *STRUCTURAL plates , *MATHEMATICAL models , *PROBLEM solving - Abstract
A thin orthotropic polygonal plate resting on the Winkler’s elastic foundation is considered in this paper. The method analysis of such plate named macroelement method has been suggested. According to this method, real plate is inscribed into rectangular contour and extended to rectangular area, which is called fundamental plate. It is union of real plate and additional part. Considered plate balanced in rectangular area and having specific links at the contour is called plate macroelement. First part of this definition is mathematical model and second is physical model of the macroelement. As examples trapeze and triangle plates were solved and results were compared with the similar results obtained by another methods. It is shown that they are in good agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. On a model of oscillations of a thin flat plate with a variety of mounts on opposite sides.
- Author
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Kal'menov, Tynysbek and Iskakova, Ulzada
- Subjects
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STRUCTURAL plates , *VIBRATION (Mechanics) , *MATHEMATICAL models , *EXISTENCE theorems , *PROBLEM solving - Abstract
In this paper we consider a model case of stationary vibrations of a thin flat plate, one side of which is embedded, the opposite side is free, and the sides are freely leaned. In mathematical modeling there is a local boundary value problem for the biharmonic equation in a rectangular domain. Boundary conditions are given on all boundary of the domain. We show that the considered problem is self-adjoint. Herewith the problem is ill-posed. We show that the stability of solution to the problem is disturbed. Necessary and sufficient conditions of existence of the problem solution are found. Spaces of the ill-posedness of the considered problem are constructed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
15. About one boundary value problem for the biharmonic equation.
- Author
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Turmetov, B. Kh. and Karachik, V. V.
- Subjects
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BOUNDARY value problems , *BIHARMONIC equations , *PROBLEM solving , *MATHEMATICAL analysis , *MATHEMATICAL models - Abstract
In the paper Neumann type boundary value problems for inhomogeneous biharmonic equation are studied. Necessary and sufficient conditions on solvability of the considered problems are established. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
16. Solving Nonlinear Problems of Heat Conduction in Layered Composites by the Boundary Element Method.
- Author
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Spevak, L. F. and Babailov, N. A.
- Subjects
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HEAT conduction , *BOUNDARY element methods , *NONLINEAR theories , *ALGORITHMS , *PROBLEM solving , *MATHEMATICAL models - Abstract
The paper deals with the development of algorithms for solving nonlinear problems of heat conduction in bodies consisting of layered metal composites. The nonlinearity of the problems is governed by the temperature dependence of the heat conductivity coefficients of the composite layer materials. Mathematical models and solution algorithms based on the boundary element method have been constructed for one-dimensional cases of heat distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
17. Modifications of the PCPT Method for HJB Equations.
- Author
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Kossaczký, I., Ehrhardt, M., and Günther, M.
- Subjects
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HAMILTON-Jacobi-Bellman equation , *PROBLEM solving , *PARTIAL differential equations , *MATHEMATICAL models , *ALGORITHMS - Abstract
In this paper we will revisit the modification of the piecewise constant policy timestepping (PCPT) method for solving Hamilton-Jacobi-Bellman (HJB) equations. This modification is called piecewise predicted policy timestepping (PPPT) method and if properly used, it may be significantly faster. We will quickly recapitulate the algorithms of PCPT, PPPT methods and of the classical implicit method and apply them on a passport option pricing problem with non-standard payoff. We will present modifications needed to solve this problem effectively with the PPPT method and compare the performance with the PCPT method and the classical implicit method. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
18. Hyperimmunity and A-computable universal numberings.
- Author
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Issakhov, Assylbek
- Subjects
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COMPUTABLE functions , *NUMBER theory , *PROBLEM solving , *SET theory , *MATHEMATICAL models - Abstract
Whether there exists a computable universal numbering for a computable family is the key question in theory of numberings. In a very general setting, this problem was explored in [Yu. L. Ershov, Theory of Numberings, Handbook of Computability Theory, North-Holland; Amsterdam: Stud. Log. Found. Math., Vol. 140, pp. 473-503, 1999]. For sets A that are Turing jumps of the empty set, the problem was treated in [S. A. Badaev, S. S. Goncharov, and A. Sorbi, Computability and Models, 11-44 (2003)] and other papers. In this work, we investigate families of total functions computable relative to hyperimmune and hyperimmune-free oracles. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
19. Bezier Curve Modeling for Intuitionistic Fuzzy Data Problem.
- Author
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Wahab, Abd Fatah, Emir Zulkifly, Mohammad Izat, and Husain, Mohd Sallehuddin
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GEOMETRIC modeling , *FUZZY sets , *INTUITIONISTIC mathematics , *MATHEMATICAL models , *PROBLEM solving - Abstract
The solution of a problem that involves uncertainty data that is characterized by complex process in which the phenomenon of incomplete information obtained is difficult to handle. Various mathematical models have been developed to handle problems involving uncertainty data. This paper introduced new concept of geometric modeling with intuitionistic fuzzy called intuitionistic fuzzy Bezier model. This model is constructed through intuitionistic fuzzy set theory and based on intuitionistic fuzzy number and intuitionistic fuzzy relation. A new control point namely intuitionistic fuzzy control point is defined. Next, the new control point is blended with the spline basis function to developed intuitionistic fuzzy Bezier model and the curve is shaped. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Fuzzy Evolutionary Algorithm to Solve Chromosomes Conflict and Its Application to Lecture Schedule Problems.
- Author
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Marwati, Rini, Yulianti, Kartika, and Pangestu, Herny Wulandari
- Subjects
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EVOLUTIONARY algorithms , *FUZZY systems , *CHROMOSOMES , *DELPHI method , *PROBLEM solving , *MATHEMATICAL models - Abstract
A fuzzy evolutionary algorithm is an integration of an evolutionary algorithm and a fuzzy system. In this paper, we present an application of a genetic algorithm to a fuzzy evolutionary algorithm to detect and to solve chromosomes conflict. A chromosome conflict is identified by existence of any two genes in a chromosome that has the same values as two genes in another chromosome. Based on this approach, we construct an algorithm to solve a lecture scheduling problem. Time codes, lecture codes, lecturer codes, and room codes are defined as genes. They are collected to become chromosomes. As a result, the conflicted schedule turns into chromosomes conflict. Built in the Delphi program, results show that the conflicted lecture schedule problem is solvable by this algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. A General Algorithm for Control Problems with Variable Parameters and Quasi-linear Models.
- Author
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Bayón, L., Grau, J. M., Ruiz, M. M., and Suárez, P. M.
- Subjects
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OPTIMAL control theory , *PROBLEM solving , *PARAMETERS (Statistics) , *ALGORITHMS , *MATHEMATICAL models , *PONTRYAGIN'S minimum principle - Abstract
This paper presents an algorithm that is able to solve optimal control problems in which the modelling of the system contains variable parameters, with the added complication that, in certain cases, these parameters can lead to control problems governed by quasi-linear equations. Combining the techniques of Pontryagin's Maximum Principle and the shooting method, an algorithm has been developed that is not affected by the values of the parameters, being able to solve conventional problems as well as cases in which the optimal solution is shown to be bang-bang with singular arcs. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. GeoGebra Helps to Know Canal Surfaces Better.
- Author
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Bímová, Daniela, Bittnerová, Daniela, and Vraštil, Ondřej
- Subjects
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COMPUTER software , *MATHEMATICAL models , *SURFACES (Technology) , *PROBLEM solving , *DYNAMIC models - Abstract
GeoGebra 5.0 is the dynamic geometric and mathematic software which dynamic tools allow the user to solve dynamic problems in a plane and as well as in the three-dimensional space. The contribution presents the dynamic applets constructed in GeoGebra 5.0 that show the origin as well as some properties of various kinds of canal surfaces. There are described the applets for constructing the canal surfaces in the paper. Some of the created canal surfaces are compared with the real life canal surface examples. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
23. Projective Lag Synchronization in Drive-Response Dynamical Networks via Hybrid Feedback Control.
- Author
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Al-Mahbashi, Ghada, Md Noorani, Mohd Salmi, and Bakar, Sakhinah Abu
- Subjects
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SYNCHRONIZATION , *COMPUTER networks , *FEEDBACK control systems , *MATHEMATICAL models , *LYAPUNOV stability , *PROBLEM solving - Abstract
This paper investigates projective lag synchronization (PLS) behavior in drive-response dynamical networks (DRDNs) model with non-identical reference node. Based on Lyapunov stability theory and hybrid feedback control method the problem of PLS with mismatch terms is solved. Finally, analytical results show that the states of the dynamical network with non-delayed coupling can be asymptotically synchronized onto a desired scaling factor under the designed controller. Moreover, the numerical simulations results demonstrate the validity of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
24. Simulation of Worms Transmission in Computer Network Based on SIRS Fuzzy Epidemic Model.
- Author
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Darti, I., Suryanto, A., and Yustianingsih, M.
- Subjects
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WORMS , *EPIDEMICS , *RUNGE-Kutta formulas , *MEMBERSHIP functions (Fuzzy logic) , *MATHEMATICAL models , *PROBLEM solving - Abstract
In this paper we study numerically the behavior of worms transmission in a computer network. The model of worms transmission is derived by modifying a SIRS epidemic model. In this case, we consider that the transmission rate, recovery rate and rate of susceptible after recovery follows fuzzy membership functions, rather than constants. To study the transmission of worms in a computer network, we solve the model using the fourth order Runge-Kutta method. Our numerical results show that the fuzzy transmission rate and fuzzy recovery rate may lead to a changing of basic reproduction number which therefore also changes the stability properties of equilibrium points. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Application of Prime Numbers to Solve Complex Instances of the Bin Packing Problem.
- Author
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De la Rosa, Rafael, Castillo, Hilda, Zavala, José C., Martínez, Alicia, and Estrada, Hugo
- Subjects
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PRIME numbers , *PROBLEM solving , *BIN packing problem , *HEURISTIC algorithms , *MATHEMATICAL models - Abstract
The problem of Bin Packing is a problem that is still open. Different strategies have been proposed using heuristic algorithms and metaheuristics to solve it without any of them can get the optimal solutions for all instances of hard28 set. This paper presents a heuristic strategy that solves instances of the hard28 set in less time than that obtained by the best algorithm. This heuristic strategy uses two types of patterns that contain instances of the hard28; approximately one sixth of the values of the objects are prime numbers, and also, about a third of their values are greater than half the capacity of the container, these features allows to fill containers before applying First Fit Decreasing heuristic. The presented heuristic significantly reduces the time needed to obtain the optimal value of some instances. The 28 instances of the hard28 set are used to evaluate the heuristic and the optimal values were obtained five them. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. A Hybrid Algorithm with Reduction Criteria for the Bin Packing Problem in One Dimension.
- Author
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Pérez, Joaquín, Castillo, Hilda, Vilariño, Darnes, Zavala, José C., De la Rosa, Rafael, and Ruiz-Vanoyed, Jorge A.
- Subjects
- *
HYBRID systems , *ALGORITHMS , *PROBLEM solving , *MATHEMATICAL models , *DATA analysis - Abstract
In this paper a hybrid algorithm is proposed to find the optimal solution for any instance of the bin packing problem one-dimensional. The hybrid algorithm considers the use of a heuristic method and a mathematical model based on flow arcs technique to find the optimal solution for an instance of 1D-BPP. The hybrid algorithm makes use of the lower bound of an instance as an element that allows it to identify if it have found the optimum or starting from this value it must find the optimal solution. The experiments were performed using the instances of the hard28 set, finding it the optimal solutions for all instances. The results show that the developed algorithm, called AHR, used 75% less time than using the Valerio model. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. An Embedded RKN Method for the Numerical Integration of Oscillatory Problems.
- Author
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Papadopoulos, D. F. and Simos, T. E.
- Subjects
- *
NUMERICAL analysis , *PROBLEM solving , *MATHEMATICAL models , *INTEGRALS , *DATA analysis - Abstract
A new embedded Runge-Kutta-Nyström method based on phase-lag properties is developed in this paper, for the numerical integration of periodic initial problems [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
28. Testing equality of selected parameters in particular nonlinear models.
- Author
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Doudová, Lucie and Hampel, David
- Subjects
- *
PARAMETER estimation , *NONLINEAR analysis , *MATHEMATICAL models , *COMPARATIVE studies , *PROBLEM solving , *SIMULATION methods & models - Abstract
In this paper, we concern at situations where we have to compare selected parameters from particular nonlinear models. A motivational examples of previously modelled data are given at the beginning. When comparing parameters from two models, it is possible to combine them into one model. But for three and more models, it is necessary to correct significance level at advance. Two approaches to solving this problem are stated, so-called Šidák correction and Bonferroni method. Results of these methods as well as results coming from the situation where significance level correction is omitted are compared based on simulated data. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
29. GPU Implementation of Physarum Cellular Automata Model.
- Author
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Dourvas, Nikolaos I., Sirakoulis, Georgios Ch., and Tsalides, Philippos
- Subjects
- *
GRAPHICS processing units , *PHYSARUM , *CELLULAR automata , *PROBLEM solving , *GRAPH theory , *MATHEMATICAL models - Abstract
In the past few decades, there is an increasing number of publications which show that solutions to complex mathematical problems can be found by applying unconventional computing methods. Among other examples, the plasmodium of Physarum Polycephalum has been intensively used for solving shortest path(s) problem, various graph problems, evaluation of transport networks, robotic control and many other engineering applications. In this paper we coupled the computing abilities of slime mould with one of the most powerful parallel computational models, namely Cellular Automata (CAs). CAs can capture the essential features of systems which global behavior emerges from the collective effect of simple components, which interact locally. Moreover, a Graphical Processing Unit (GPU) implementation will exploit the prominent feature of parallelism that CA structures inherently possess in contrast to the serial computers, thus accelerating the response of the proposed model. As a result, a slime mould CA based model in graphics processing unit (GPU) using CUDA programming model to describe and mimic the behavior of a plasmodium in a maze. In this way we are able to produce a virtual lab speeding up significantly the biological paradigm in GPU. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
30. Enhancements of Evolutionary Algorithm for the Complex Requirements of a Nurse Scheduling Problem.
- Author
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Lim Huai Tein and Ramli, Razamin
- Subjects
- *
EVOLUTIONARY algorithms , *MATHEMATICAL models , *PROBLEM solving , *PRODUCTION scheduling , *OPERATOR theory - Abstract
Over the years, nurse scheduling is a noticeable problem that is affected by the global nurse turnover crisis. The more nurses are unsatisfied with their working environment the more severe the condition or implication they tend to leave. Therefore, the current undesirable work schedule is partly due to that working condition. Basically, there is a lack of complimentary requirement between the head nurse's liability and the nurses' need. In particular, subject to highly nurse preferences issue, the sophisticated challenge of doing nurse scheduling is failure to stimulate tolerance behavior between both parties during shifts assignment in real working scenarios. Inevitably, the flexibility in shifts assignment is hard to achieve for the sake of satisfying nurse diverse requests with upholding imperative nurse ward coverage. Hence, Evolutionary Algorithm (EA) is proposed to cater for this complexity in a nurse scheduling problem (NSP). The restriction of EA is discussed and thus, enhancement on the EA operators is suggested so that the EA would have the characteristic of a flexible search. This paper consists of three types of constraints which are the hard, semi-hard and soft constraints that can be handled by the EA with enhanced parent selection and specialized mutation operators. These operators and EA as a whole contribute to the efficiency of constraint handling, fitness computation as well as flexibility in the search, which correspond to the employment of exploration and exploitation principles. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
31. Continuity of the sequential product of sequential quantum effect algebras.
- Author
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Qiang Lei, Xiaochao Su, and Junde Wu
- Subjects
- *
MATHEMATICAL models , *QUANTUM theory , *ALGEBRA , *OPERATOR theory , *TOPOLOGY , *PROBLEM solving - Abstract
In order to study quantum measurement theory, sequential product defined by A × B = A1/2BA1/2 for any two quantum effects A, B has been introduced. Physically motivated conditions ask the sequential product to be continuous with respect to the strong operator topology. In this paper, we study the continuity problems of the sequential product A × B = A1/2BA1/2 with respect to other important topologies, such as norm topology, weak operator topology, order topology, and interval topology. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
32. An improved GRMOD heuristic for container loading problem.
- Author
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Ho, Ziao-Fung, Lee, Lai-Soon, Majid, Zanariah Abdul, and Seow, Hsin-Vonn
- Subjects
- *
LOADING & unloading , *UNITIZED cargo systems , *PACKING for shipment , *BOXES , *PROBLEM solving , *HEURISTIC algorithms , *MATHEMATICAL models - Abstract
The Container Loading Problem (CLP) is a study of loading a subset of goods or parcels of different sizes into a three-dimensional rectangular container of fixed dimensions such that the volume of packed boxes is maximized. In this paper, an improved version of the modified George and Robinson heuristic (iGRMOD) is developed to solve the CLP. Comparison computational results on benchmark data set from the literature will be presented. The performances of the iGRMOD are superior than the GRMOD and other heuristics reported in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
33. Ant colony optimization for solving university facility layout problem.
- Author
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Mohd Jani, Nurul Hafiza, Mohd Radzi, Nor Haizan, and Ngadiman, Mohd Salihin
- Subjects
- *
ANT algorithms , *COLLEGE facilities , *PROBLEM solving , *DISTRIBUTED computing , *COMBINATORICS , *TRAVELING salesman problem , *MATHEMATICAL models - Abstract
Quadratic Assignment Problems (QAP) is classified as the NP hard problem. It has been used to model a lot of problem in several areas such as operational research, combinatorial data analysis and also parallel and distributed computing, optimization problem such as graph portioning and Travel Salesman Problem (TSP). In the literature, researcher use exact algorithm, heuristics algorithm and metaheuristic approaches to solve QAP problem. QAP is largely applied in facility layout problem (FLP). In this paper we used QAP to model university facility layout problem. There are 8 facilities that need to be assigned to 8 locations. Hence we have modeled a QAP problem with n ≤ 10 and developed an Ant Colony Optimization (ACO) algorithm to solve the university facility layout problem. The objective is to assign n facilities to n locations such that the minimum product of flows and distances is obtained. Flow is the movement from one to another facility, whereas distance is the distance between one locations of a facility to other facilities locations. The objective of the QAP is to obtain minimum total walking (flow) of lecturers from one destination to another (distance). [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
34. Wavelet neural networks initialization using hybridized clustering and harmony search algorithm: Application in epileptic seizure detection.
- Author
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Zainuddin, Zarita, Lai, Kee Huong, and Ong, Pauline
- Subjects
- *
WAVELETS (Mathematics) , *ARTIFICIAL neural networks , *SEARCH algorithms , *DIAGNOSIS of epilepsy , *MATHEMATICAL models , *PROBLEM solving , *PARAMETER estimation - Abstract
Artificial neural networks (ANNs) are powerful mathematical models that are used to solve complex real world problems. Wavelet neural networks (WNNs), which were developed based on the wavelet theory, are a variant of ANNs. During the training phase of WNNs, several parameters need to be initialized; including the type of wavelet activation functions, translation vectors, and dilation parameter. The conventional k-means and fuzzy c-means clustering algorithms have been used to select the translation vectors. However, the solution vectors might get trapped at local minima. In this regard, the evolutionary harmony search algorithm, which is capable of searching for near-optimum solution vectors, both locally and globally, is introduced to circumvent this problem. In this paper, the conventional k-means and fuzzy c-means clustering algorithms were hybridized with the metaheuristic harmony search algorithm. In addition to obtaining the estimation of the global minima accurately, these hybridized algorithms also offer more than one solution to a particular problem, since many possible solution vectors can be generated and stored in the harmony memory. To validate the robustness of the proposed WNNs, the real world problem of epileptic seizure detection was presented. The overall classification accuracy from the simulation showed that the hybridized metaheuristic algorithms outperformed the standard k-means and fuzzy c-means clustering algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
35. Exploring the future with anticipatory networks.
- Author
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Skulimowski, A. M. J.
- Subjects
- *
STATISTICAL decision making , *MULTIPLE criteria decision making , *MULTIGRAPH , *MATHEMATICAL optimization , *PROBLEM solving , *MATHEMATICAL models - Abstract
This paper presents a theory of anticipatory networks that originates from anticipatory models of consequences in multicriteria decision problems. When making a decision, the decision maker takes into account the anticipated outcomes of each future decision problem linked by the causal relations with the present one. In a network of linked decision problems, the causal relations are defined between time-ordered nodes. The scenarios of future consequences of each decision are modeled by multiple vertices starting from an appropriate node. The network is supplemented by one or more relations of anticipation, or future feedback, which describe a situation where decision makers take into account the anticipated results of some future optimization problems while making their choice. So arises a multigraph of decision problems linked causally and by one or more anticipation relation, termed here the anticipatory network. We will present the properties of anticipatory networks and propose a method of reducing, transforming and using them to solve current decision problems. Furthermore, it will be shown that most anticipatory networks can be regarded as superanticipatory systems, i.e. systems that are anticipatory in the Rosen sense and contain a future model of at least one other anticipatory system. The anticipatory networks can also be applied to filter the set of future scenarios in a foresight exercise. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
36. An inverse preconditioner for a free surface ocean circulation model.
- Author
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Farina, R., Cuomo, S., and De Michele, P.
- Subjects
- *
OCEAN circulation , *FREE surfaces , *NUMERICAL analysis , *ELLIPTIC functions , *LINEAR systems , *PROBLEM solving , *GRAPHICS processing units , *MATHEMATICAL models - Abstract
In this paper a preconditioner for a numerical global circulation ocean model is presented. Starting from the discretization of an elliptic Laplace problem the associated linear system is solved by means of the Preconditioned Conjugate Gradient Method (PCG). In this work, we observe that the performance of the PCG solver depends on the grid resolutions and the Laplace coefficients. To address these problems we propose a new preconditioning technique. Finally, an implementation of the PCG solver with an inverse built "ad-hoc" preconditioner on multi-core GPU architecture is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
37. Some operational tools for solving fractional and higher integer order differential equations: A survey on their mutual relations.
- Author
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Kiryakova, Virginia S.
- Subjects
- *
INTEGERS , *PROBLEM solving , *DIFFERENTIAL equations , *LAPLACE transformation , *OPERATIONAL calculus , *MATHEMATICAL models , *FRACTIONAL integrals - Abstract
The Laplace Transform (LT) serves as a basis of the Operational Calculus (OC), widely explored by engineers and applied scientists in solving mathematical models for their practical needs. This transform is closely related to the exponential and trigonometric functions (exp, cos, sin) and to the classical differentiation and integration operators, reducing them to simple algebraic operations. Thus, the classical LT and the OC give useful tool to handle differential equations and systems with constant coefficients. Several generalizations of the LT have been introduced to allow solving, in a similar way, of differential equations with variable coefficients and of higher integer orders, as well as of fractional (arbitrary non-integer) orders. Note that fractional order mathematical models are recently widely used to describe better various systems and phenomena of the real world. This paper surveys briefly some of our results on classes of such integral transforms, that can be obtained from the LT by means of "transmutations" which are operators of the generalized fractional calculus (GFC). On the list of these Laplace-type integral transforms, we consider the Borel-Dzrbashjan, Meijer, Kra¨tzel, Obrechkoff, generalized Obrechkoff (multi-index Borel-Dzrbashjan) transforms, etc. All of them are G- and H-integral transforms of convolutional type, having as kernels Meijer's G- or Fox's H-functions. Besides, some special functions (also being G- and H-functions), among them - the generalized Bessel-type and Mittag-Leffler (M-L) type functions, are generating Gel'fond-Leontiev (G-L) operators of generalized differentiation and integration, which happen to be also operators of GFC. Our integral transforms have operational properties analogous to those of the LT - they do algebrize the G-L generalized integrations and differentiations, and thus can serve for solving wide classes of differential equations with variable coefficients of arbitrary, including non-integer order. Throughout the survey, we illustrate the parallels in the relationships: Laplace type integral transforms - special functions as kernels - operators of generalized integration and differentiation generated by special functions - special functions as solutions of related differential equations. The role of the so-called Special Functions of Fractional Calculus is emphasized. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
38. Solving seismological problems using SGRAPH program: I-source parameters and hypocentral location.
- Author
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Abdelwahed, Mohamed F.
- Subjects
- *
SEISMOLOGY , *PROBLEM solving , *DATA analysis , *GRAPHICAL user interfaces , *WINDOWS (Graphical user interfaces) , *MATHEMATICAL models , *EARTHQUAKES , *PARAMETER estimation - Abstract
SGRAPH program [1] is considered one of the seismological programs that maintain seismic data. SGRAPH is considered unique for being able to read a wide range of data formats and manipulate complementary tools in different seismological subjects in a stand-alone Windows-based application. SGRAPH efficiently performs the basic waveform analysis and solves advanced seismological problems. The graphical user interface (GUI) utilities and the Windows facilities such as, dialog boxes, menus, and toolbars simplified the user interaction with data. SGRAPH supported the common data formats like, SAC, SEED, GSE, ASCII, and Nanometrics Y-format, and others. It provides the facilities to solve many seismological problems with the built-in inversion and modeling tools. In this paper, I discuss some of the inversion tools built-in SGRAPH related to source parameters and hypocentral location estimation. Firstly, a description of the SGRAPH program is given discussing some of its features. Secondly, the inversion tools are applied to some selected events of the Dahshour earthquakes as an example of estimating the spectral and source parameters of local earthquakes. In addition, the hypocentral location of these events are estimated using the Hypoinverse 2000 program [2] operated by SGRAPH. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
39. Some Open Problems in Science of Complex Systems.
- Author
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Sanayei, Ali
- Subjects
- *
PROBLEM solving , *SYSTEMS theory , *COMPUTATIONAL complexity , *CHAOS theory , *MATHEMATICAL models - Abstract
This paper includes some various open problems in science of complex systems. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
40. AN INTERACTIVE ALGORITHM FOR SOLVING INTEGER GOAL PROGRAMMING PROBLEMS.
- Author
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Suwendy, Maries, Sinuhaji, Theresa A., Maulana, B., Prana, Afen, Elyakin, Victor A., and Zarlis, M.
- Subjects
- *
INTEGER programming , *PROBLEM solving , *ALGORITHMS , *MULTIPLE criteria decision making , *ITERATIVE methods (Mathematics) , *LINEAR programming , *MATHEMATICAL models - Abstract
Integer goal programming problems arise quite naturally in many real-world applications. In this paper, we propose a reference direction approach and interactive algorithm to solve integer goal programming problem. We use analytic hierarchy process (AHP) to get the reference direction. At each iteration, only one integer linear programming problem is solved to get an efficient solution. Through analytic hierarchy process the decision maker has to provide the preference point such that the original problem has been transformed into linear integer programming model. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
41. Two vortex-blob regularization models for vortex sheet motion.
- Author
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Sung-Ik Sohn
- Subjects
- *
REGULARIZATION parameter , *VORTEX motion , *WAVENUMBER , *STABILITY of linear systems , *MATHEMATICAL models , *PROBLEM solving - Abstract
Evolving vortex sheets generally form singularities in finite time. The vortex blob model is an approach to regularize the vortex sheet motion and evolve past singularity formation. In this paper, we thoroughly compare two such regularizations: the Krasnytype model and the Beale-Majda model. It is found from a linear stability analysis that both models have exponentially decaying growth rates for high wavenumbers, but the Beale-Majda model has a faster decaying rate than the Krasny model. The Beale-Majda model thus gives a stronger regularization to the solution. We apply the blob models to the two example problems: a periodic vortex sheet and an elliptically loaded wing. The numerical results show that the solutions of the two models are similar in large and small scales, but are fairly different in intermediate scales. The sheet of the Beale-Majda model has more spiral turns than the Krasny-type model for the same value of the regularization parameter d. We give numerical evidences that the solutions of the two models agree for an increasing amount of spiral turns and tend to converge to the same limit as d is decreased. The inner spiral turns of the blob models behave differently with the outer turns and satisfy a self-similar form. We also examine irregular motions of the sheet at late times and find that the irregular motions shrink as d is decreased. This fact suggests a convergence of the blob solution to the weak solution of infinite regular spiral turns. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
42. On the relationship between the classical Dicke-Jaynes-Cummings-Gaudin model and the nonlinear Schrödinger equation.
- Author
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Du, Dianlou and Geng, Xue
- Subjects
- *
MATHEMATICAL models , *NONLINEAR equations , *SCHRODINGER equation , *PROBLEM solving , *SET theory , *HAMILTON-Jacobi equations , *CASIMIR effect - Abstract
In this paper, the relationship between the classical Dicke-Jaynes-Cummings-Gaudin (DJCG) model and the nonlinear Schrödinger (NLS) equation is studied. It is shown that the classical DJCG model is equivalent to a stationary NLS equation. Moreover, the standard NLS equation can be solved by the classical DJCG model and a suitably chosen higher order flow. Further, it is also shown that classical DJCG model can be transformed into the classical Gaudin spin model in an external magnetic field through a deformation of Lax matrix. Finally, the separated variables are constructed on the common level sets of Casimir functions and the generalized action-angle coordinates are introduced via the Hamilton-Jacobi equation. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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