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Showing papers by "Bauhaus University, Weimar published in 1998"


Journal ArticleDOI
TL;DR: The method most commonly used to estimate the normal vector at a vertex of a polygonal surface is extended so that it also incorporates the geometric contribution of each facet, considering the angle under which a facet is incident to the vertex in question.
Abstract: The method most commonly used to estimate the normal vector at a vertex of a polygonal surface averages the normal vectors of the facets incident to the vertex considered. The vertex normal obtained in this way may vary depending on the tessellation of the polygonal surface since the normal of each incident facet contributes equally to the normal in the vertex. To overcome this drawback, we extend the method so that it also incorporates the geometric contribution of each facet, considering the angle under which a facet is incident to the vertex in question.

139 citations


Journal ArticleDOI
TL;DR: In this article, a case study of a strike of day care workers in West Berlin in the winter of 1989-90 is used to compare inclusive and exclusive forms of solidarity and their consequences for organizational practices.
Abstract: From the perspective of gender theory, the intersections among gender, class, and race make it difficult, if not impossible, to assign political issues and identities to just one social movement. Instead, the negotiation of movement ownership of issues and identities occurs through interaction among social movements, including interactions that create denial and distance. This article takes the interaction of labor organizing and feminism as the lens for studying movement interaction at three levels: opportunity structure, organizing practices, and framing ideas. Using a case study of a strike of day care workers in West Berlin in the winter of 1989-90, it contrasts inclusive and exclusive forms of solidarity and their consequences for organizational practices. This particular strike received little support from either feminists or the labor movement and eventually failed, an outcome that can be seen as reflecting the weakness of structural and organizational supports for frames favoring inclusive solidarity.

79 citations


Journal ArticleDOI
TL;DR: In this paper, an overflown, submerged flexible curtain (SFC, 160 m long, 6 m deep) perpendicular to the flow direction was installed in the Haselbach mouth region of the Saidenbach Reservoir (Saxony, Germany).

17 citations


Journal ArticleDOI
TL;DR: A discrete regular structure called hyperlattice used for defining n-dimensional raster geometry is presented, and algorithms for rasterizing generic curves and straight lines onto n- dimensional lattices are presented.

11 citations


Proceedings ArticleDOI
22 Jun 1998
TL;DR: The article examines and evaluates the different parameters used in the computation of the normals, such as neighbourhood size and weighting factors, both from a numerical and from a visual point of view.
Abstract: A method is examined which computes normal vectors on binary discrete surfaces by making use of the local separation criterion of surfaces. The method considers points in the neighbourhood of a surface point in object space to recover information about the local surface inclination. The article examines and evaluates the different parameters used in the computation of the normals, such as neighbourhood size and weighting factors, both from a numerical and from a visual point of view. Moreover far the discrete space the use of spherical neighbourhoods is introduced for the computation, and the vectors computed from the two different sides of a surface are compared.

8 citations


Proceedings ArticleDOI
15 Mar 1998
TL;DR: In this article, the authors developed a sensor based pipe inspection system named RODIAS, which consists of a remotely controlled mobile robot which carries intelligent sensors for on-line sewerage inspection purpose.
Abstract: Damages of pipes can be inspected and graded by TV technology available on the market. Remotely controlled vehicles carry a TV-camera through pipes. Thus, depending on the experience and the capability of the operator, diagnosis failures can not be avoided. The classification of damages requires the knowledge of the exact geometrical dimensions of the damages such as width and depth of cracks, fractures and defect connections. Within the framework of a joint R&D project a sensor based pipe inspection system named RODIAS has been developed with two partners from industry and research institute. It consists of a remotely controlled mobile robot which carries intelligent sensors for on-line sewerage inspection purpose. The sensor is based on a 3D-optical sensor and a laser distance sensor. The laser distance sensor is integrated in the optical system of the camera and can measure the distance between camera and object. The angle of view can be determined from the position of the pan and tilt unit. With coordinate transformations it is possible to calculate the spatial coordinates for every point of the video image. So the geometry of an object can be described exactly. The company Optimess has developed TriScan32, a special software for pipe condition classification. The user can start complex measurements of profiles, pipe displacements or crack widths simply by pressing a push-button. The measuring results are stored together with other data like verbal damage descriptions and digitized images in a data base.

3 citations


Book ChapterDOI
01 Jan 1998
TL;DR: Two definitions of the standard pile problem are considered: in terms of graphs and its geometric interpretation.
Abstract: Consider two definitions of the standard pile problem: in terms of graphs and its geometric interpretation.

1 citations


Journal ArticleDOI
TL;DR: In this article, the influence of local ground conditions on the seismic action is accounted for by considering three subsoil classes (A. B, C) being described by different stratigraphic profiles.

1 citations


Book ChapterDOI
01 Jan 1998
TL;DR: In this paper, a system of biharmonic equations coupled by boundary conditions is studied, where boundary conditions contain some combinations of the values, div, curl, and grad of the solution.
Abstract: In this paper we study a system of biharmonic equations coupled by the boundary conditions. These boundary conditions contain some combinations of the values, div, curl, and grad of the solution. It is the aim of the paper also to demonstrate the application of Clifford analytic methods developed for second order elliptic problems to the solution of higher order boundary value problems. The results on a special boundary value problem for the biharmonic equation will be used for the investigation of some first order systems of partial differential equations. We study a theoretical problem connected with the ∂-problem and the solution of a Beltrami system by a fixed-point iteration.