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Abstract

On 16 November 2004 intemational community will commemorate the tenth anniversary of the entry into force of the Montego Bay Convention. The number of parties to the Convention currently stands at 145. This represents considerable progress towards universality. Ten years after its entry into force state practice has shown a strong adherence to its principles and norms. The Convention established the International Seabed Authority, the International Tribunal of the Law of the Sea and the Commission on the Limits of the Continental Shelf. The law of the sea is at present challenged by new urgent and complex problems such as terrorism, piracy, organized crime, overfishing and degradation of the marine environment. lt articulates the need of evolution and accomodation to the changing realities and interests. Nevertheless, whatever emerging issues the intemational community will face in the future, the Convention will provide the necessary legal framework for the steady evolution of the law of the sea.
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Authors and Affiliations

Janusz Symonides
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Abstract

This paper presents a methodology for contact detection between convex quadric surfaces using its implicit equations. With some small modifications in the equations, one can model superellipsoids, superhyperboloids of one or two sheets and supertoroids. This methodology is to be implemented on a multibody dynamics code, in order to simulate the interpenetration between mechanical systems, particularly, the simulation of collisions with motor vehicles and other road users, such as cars, motorcycles and pedestrians.

The contact detection of two bodies is formulated as a convex nonlinear constrained optimization problem that is solved using two methods, an Interior Point method (IP) and a Sequential Quadratic Programming method (SQP), coded in MATLAB and FORTRAN environment, respectively. The objective function to be minimized is the distance between both surfaces. The design constraints are the implicit superquadrics surfaces equations and operations between its normal vectors and the distance itself. The contact points or the points that minimize the distance between the surfaces are the design variables. Computational efficiency can be improved by using Bounding Volumes in contact detection pre-steps. First one approximate the geometry using spheres, and then Oriented Bounding Boxes (OBB).

Results show that the optimization technique suits for the accurate contact detection between objects modelled by implicit superquadric equations.

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Authors and Affiliations

Ricardo José Fontes Portal
João Manuel Pereira Dias
Luís Alberto Gonçalves de Sousa
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Abstract

The protection of Polish architectural heritage in the former eastern borderlands, accomplished through the conservation and technical securing of historical structures, constitutes one of the main programmes that are implemented by the Ministry of Culture and National Heritage. Currently, many Polish historical buildings in the former eastern borderlands are in a very bad technical condition. The load-bearing systems of these elements, as well as elements of their finish, require immediate emergency securing work. The basic steps that precede conservation work are emergency structural works, which guarantee the durability and stability of the entire historical substance. The specifics and complexity of the problem of the failure of historical buildings often demands an in-depth analysis of a series of factors that are difficult to measure and which are responsible for the cause and effect relationship during the early stage of the technical evaluation of a structure. The analyses of failures of numerous historical structures, for instance that were carried out by the authors, have become the inspiration for the search for effective methods of analysis that would allow for an in-depth analysis of the causes and effects of the failures in question. The DEMATEL method (Decision Making Trial and Evaluation Laboratory) that has been presented in this work, and its fuzzy extension, has lately become one of the more popular methods used in the cause-and-effect analysis of various phenomena. The authors demonstrated how this method works on the example of the evaluation and securing of the load-bearing system of the XVII Collegiate church of the Holy Trinity in the town of Olykha in the Volhynskiy Oblast, Ukraine.

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Authors and Affiliations

G. Śladowski
R. Paruch

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