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Hull

About: Hull is a(n) research topic. Over the lifetime, 13969 publication(s) have been published within this topic receiving 82658 citation(s).
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Journal ArticleDOI
Aldo Laurentini1Institutions (1)
TL;DR: This paper addresses the problem of finding which parts of a nonconvex object are relevant for silhouette-based image understanding and introduces the geometric concept of visual hull of a 3-D object, which is the maximal object silhouette-equivalent to S.
Abstract: Many algorithms for both identifying and reconstructing a 3-D object are based on the 2-D silhouettes of the object. In general, identifying a nonconvex object using a silhouette-based approach implies neglecting some features of its surface as identification clues. The same features cannot be reconstructed by volume intersection techniques using multiple silhouettes of the object. This paper addresses the problem of finding which parts of a nonconvex object are relevant for silhouette-based image understanding. For this purpose, the geometric concept of visual hull of a 3-D object is introduced. This is the closest approximation of object S that can be obtained with the volume intersection approach; it is the maximal object silhouette-equivalent to S, i.e., which can be substituted for S without affecting any silhouette. Only the parts of the surface of S that also lie on the surface of the visual hull can be reconstructed or identified using silhouette-based algorithms. The visual hull depends not only on the object but also on the region allowed to the viewpoint. Two main viewing regions result in the external and internal visual hull. In the former case the viewing region is related to the convex hull of S, in the latter it is bounded by S. The internal visual hull also admits an interpretation not related to silhouettes. Algorithms for computing visual hulls are presented and their complexity analyzed. In general, the visual hull of a 3-D planar face object turns out to be bounded by planar and curved patches. >

1,519 citations


Journal ArticleDOI
TL;DR: The results of this study provide guidance as to the amount of money that can be reasonably spent for research, development, acquisition, and implementation of new technologies or management strategies to combat hull fouling.
Abstract: In the present study, the overall economic impact of hull fouling on a mid-sized naval surface ship (Arleigh Burke-class destroyer DDG-51) has been analyzed. A range of costs associated with hull fouling was examined, including expenditures for fuel, hull coatings, hull coating application and removal, and hull cleaning. The results indicate that the primary cost associated with fouling is due to increased fuel consumption attributable to increased frictional drag. The costs related to hull cleaning and painting are much lower than the fuel costs. The overall cost associated with hull fouling for the Navy's present coating, cleaning, and fouling level is estimated to be $56M per year for the entire DDG-51 class or $1B over 15 years. The results of this study provide guidance as to the amount of money that can be reasonably spent for research, development, acquisition, and implementation of new technologies or management strategies to combat hull fouling.

882 citations


Book
01 Jan 1934
Abstract: In those early days we were often asked why we had come to live on Halsted Street when we could afford to live somewhere else. I remember one man who used to shake his head and say it was “the strangest thing he had met in his experience,” but who was finally convinced that it was “not strange but natural.” In time it came to seem natural to all of us that the Settlement should be there. If it is natural to feed the hungry and care for the sick, it is certainly natural to give pleasure to the young, comfort to the aged, and to minister to the deep-seated craving for social intercourse that all men feel. Whoever does it is rewarded by something which, if not gratitude, is at least spontaneous and vital and lacks that irksome sense of obligation with which a substantial benefit is too often acknowledged. . . .

739 citations


Proceedings Article
29 Nov 1999
TL;DR: HC4, an algorithm to enforce hull consistency without decomposing complex constraints into primitives is presented, and BC4, a new algorithm to efficiently enforce box consistency is described, which is shown to significantly outperform both HC3 and BC3.
Abstract: Most interval-based solvers in the constraint logic programming framework are based on either hull consistency or box consistency (or a variation of these ones) to narrow domains of variables involved in continuous constraint systems. This paper first presents HC4, an algorithm to enforce hull consistency without decomposing complex constraints into primitives. Next, an extended definition for box consistency is given and the resulting consistency is shown to subsume hull consistency. Finally, BC4, a new algorithm to efficiently enforce box consistency is described, that replaces BC3—the “original” solely Newton-based algorithm to achieve box consistency—by an algorithm based on HC4 and BC3 taking care of the number of occurrences of each variable in a constraint. BC4 is then shown to significantly outperform both HC3 (the original algorithm enforcing hull consistency by decomposing constraints) and BC3.

403 citations


Journal ArticleDOI
Abstract: In an earlier publication, a statistical method was presented for the determination of the required propulsive power at the initial design stage of a ship. This method was developed through a regression analysis of random model experiments and full-scale data, available at the Netherlands Ship Model Basin. Because the accuracy of the method was reported to he insufficient when unconventional combinations of main parameters were used, an attempt is made in the present article to extend the method by adjusting the original numerical prediction model to test data obtained in some specific cases. This adaptation of the method has resulted in a set of prediction formulae with a wider range of application. Nevertheless, it is pointed out that the given modifications have a tentative character only, because the adjustments are based on a small number of experiments. In any case, the application is limited to hull forms resembling the average ship described by the main dimensions and form coefficients used in the method. The extension of the method was focused on improving the power prediction for high-block ships with low L/B ratios, and for slender naval ships with complex appendage arrangements and immersed transom sterns.

386 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20226
2021300
2020449
2019589
2018696
2017640