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Abstract

During object-relational database physical structure design, problems are caused by three factors: ambiguity of transformations of conceptual model, multiplicity of quality assessment criteria, and a lack of constructive model. In the present study a constructive hierarchical model of physical database structure has been developed. Implementations are used in XML, SQL and Java languages. Multi-criterial structure optimisation method has also been developed. Structure variation space is generated using transformation rule database. Prototype has been implemented within the framework of the research.

problem. Technical Transactions 6 , 119-134. 4. Mikulski, L and Laskowski, H 2009. Control theory in composite structure optimizing. Measurement Automation Monitoring 6 , 346-351. 5. Mikulski, L 2004. Control structure in optimization problems of bar systems. International Journal of Applied Mathematics and Computer Science 14 , 515-529. 6. Pesch, HJ 1994. A practical guide to the solution of real-life optimal control problems. Control and Cybernetics 23 , 7-60. 7. Sobczyk, Sz and Mikulski, L 2016. A method of optimum selection of post-tensioned concrete beam

Structural weight minimization of high speed vehicle-passenger catamaran by genetic algorithm

Reduction of hull structural weight is the most important aim in the design of many ship types. But the ability of designers to produce optimal designs of ship structures is severely limited by the calculation techniques available for this task. Complete definition of the optimal structural design requires formulation of size-topology-shape-material optimization task unifying optimization problems from four areas and effective solution of the problem. So far a significant progress towards solution of this problem has not been achieved. In other hand in recent years attempts have been made to apply genetic algorithm (GA) optimization techniques to design of ship structures. An objective of the paper was to create a computer code and investigate a possibility of simultaneous optimization of both topology and scantlings of structural elements of large spacial sections of ships using GA. In the paper GA is applied to solve the problem of structural weight minimisation of a high speed vehicle-passenger catamaran with several design variables as dimensions of the plate thickness, longitudinal stiffeners and transverse frames and spacing between longitudinals and transversal members. Results of numerical experiments obtained using the code are presented. They shows that GA can be an efficient optimization tool for simultaneous design of topology and sizing high speed craft structures.

Comparison of different computational methods for water structure optimisation

We have compared several computational techniques with the aim to compute the radial distribution function (RDF) as a good characterization of water structure. In particular, we have used molecular mechanic (AMBER99), semi-empirical (AM1, PM3, PM6) and ab initio (DFT) technique. It has been shown that molecular mechanic gives very poor results in the case of water RDF. Ab initio techniques which are in general accepted as very exact methods, in the case of water underestimate intermolecular interaction. Unexpectedly, the semi-empirical method with PM6 parameterisation gives the best results in comparison with RDF measured by X-ray scattering experiment.

Abstract

Background and Purpose: In a complex strictly hierarchical organizational structure, undesired oscillations may occur, which have not yet been adequately addressed. Therefore, parameter values, which define fluctuations and transitions from one state to another, need to be optimized to prevent oscillations and to keep parameter values between lower and upper bounds. The objective was to develop a simulation model of hierarchical organizational structure as a web application to help in solving the aforementioned problem.

Design/Methodology/Approach: The hierarchical structure was modeled according to the principles of System Dynamics. The problem of the undesired oscillatory behavior was addressed with deterministic finite automata, while the flow parameter values were optimized with genetic algorithms. These principles were implemented as a web application with JavaScript/ECMAScript.

Results: Genetic algorithms were tested against well-known instances of problems for which the optimal analytical values were found. Deterministic finite automata was verified and validated via a three-state hierarchical organizational model, successfully preventing the oscillatory behavior of the structure.

Conclusion: The results indicate that the hierarchical organizational model, genetic algorithms and deterministic finite automata have been successfully implemented with JavaScript as a web application that can be used on mobile devices. The objective of the paper was to optimize the flow parameter values in the hierarchical organizational model with genetic algorithms and finite automata. The web application was successfully used on a three-state hierarchical organizational structure, where the optimal flow parameter values were determined and undesired oscillatory behavior was prevented. Therefore, we have provided a decision support system for determination of quality restructuring strategies.

Abstract

Paper focuses on the problems of application of extreme energy principles and nonlinear mathematical programing in the theory of structural shakedown. By means of energy principles, which describes the true stress-strain state conditions of the structure, the dual mathematical models of analysis problems are formed (static and kinematic formulations). It is shown how common mathematical model of the structures optimization at shakedown with safety and serviceability constraints (according to the ultimate limit state (ULS) and serviceability limit state (SLS) requirements) on the basis of previously mentioned mathematical models is formed. The possibilities of optimization problem solution in the context of physical interpretation of optimality criterion of Rosen’s algorithm are analyzed.

Abstract

This article opens a suite dedicated to State Treasury financial structure optimization. It further develops our previous excursus on State Treasury mechanism, operation policies and practice, alignment to EU regulations, and the influence of fiscal pressure on the EU states economies.

This article concentrates on risk prevention and containment of the possible impact. It further describes the financing policy that has been adopted. The following section describes the effects of the applied policies and practice, as well as the accessed financial package.

We have included a lessons learned section, to outline what we strongly believe should achieved for enriching the data sets and processing automation - these being instrumental to ensure the accuracy and relevance of the decision process and actions.

We finally project the main theme of the future articles and to outline the need of competitive central administration partner for the national business community - which is tightly and ever tighter connected to its global counterparties.

Abstract

The sandwich structures have multifold advantages with respect to other types of structures. Besides the architectural possibilities due to their appearance, those structures can carry the same or even higher loads than some other similar structures. Optimization of the sandwich columns with the truss core, subjected to the compressive axial load, is presented in this paper. The two types of optimization were performed: the three-parameter and the four-parameter optimization - the so called full optimization. The optimization of the column geometry (face thickness, core member height and core member diameter and core height) was performed, from the aspect of the minimal weight of the structure in terms of the load index. It was performed for four types of restrictions imposed by the corresponding column failure modes: column buckling, truss macro-buckling, local buckling of the face and face wrinkling. The tree-parameter optimization resulted in somewhat larger weight of the column than the full, four-parameter optimization.

Abstract

Classical optimization problems of metal structures confined mainly with 1st class cross-sections. But in practice it is common to use the cross-sections of higher classes. In this paper, a new mathematical model for described shakedown optimization problem for metal structures, which elements are designed from 1st to 4th class cross-sections, under variable quasi-static loads is presented. The features of limited plastic redistribution of forces in the structure with thin-walled elements there are taken into account. Authors assume the elastic-plastic flexural buckling in one plane without lateral torsional buckling behavior of members. Design formulae for Methods 1 and 2 for members are analyzed. Structures stiffness constrains are also incorporated in order to satisfy the limit serviceability state requirements. With the help of mathematical programming theory and extreme principles the structure optimization algorithm is developed and justified with the numerical experiment for the metal plane frames.

Abstract

The electronic structure and magnetic properties of Heusler alloys (Ni2FeIn) have been studied by first principle calculations. The possible tetragonal martensitic transformation has been predicted and the structure optimization was made on cubic austenitic Ni2FeIn in Cu2MnAl type. The equilibrium lattice constant of austenitic Ni2FeIn is 6.03 Å. In tetragonal phase, the global energy minimum occurs at c/a = 1.29. The corresponding equilibrium lattice constants for martensite Ni2FeIn are a = b = 5.5393 Å and c = 7.1457 Å, respectively. In the austenitic phase, E F is located at the peak in the minority DOS for c/a = 0.96 to 1.20, but in the martensitic phase, E F moves to the bottom of the valley in the minority DOS, reducing the value of N(E F) effectively. Both austenitic and martensitic phases are ferromagnetic and the Ni and Fe partial moments contribute mainly to the total moments. Therefore, the martensitic transformation behavior in Ni2FeIn is predicted.