Constraint is an important aspect of role based access control and is sometimes argued to be the principal motivation for role based access control (RBAC). But so far few authors have discussed consistency maintenance...
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Constraint is an important aspect of role based access control and is sometimes argued to be the principal motivation for role based access control (RBAC). But so far few authors have discussed consistency maintenance for constraint in RBAC model. Based on researches of constraints among roles and types of inconsistency among constraints, this paper introduces corresponding formal rules, rule based reasoning and corresponding methods to detect, avoid and resolve these inconsistencies. Finally, the paper introduces briefly the application of consistency maintenance in ZD PDM, an enterprise oriented product data management (PDM) system.
It has been said that if HTML makes easy things easy, XML will make hard things possible. XML has been heralded as the enabling technology for a Brave New Web, a whole new generation of Web applications. However, to f...
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A major problem in simulating communication systems is that, below a certain error rate, software simulation is too slow. Also software often does not allow to simulate the real system but only a somehow simplified ve...
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Head detection is an important, but difficult task, if no restrictions such as static illumination, frontal face appearance or uniform background can be assumed. We present a system that is able to perform head detect...
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In this paper we deal with performance improvement of robust PCA algorithms by replacing regular subsampling of images by an irregular image pyramid adapted to the expected image content. The irregular pyramid is a st...
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One of the main problems of the modern technology is in the increase of the viability of materials and structures' under dynamic loading. The work studies the method of complex structures analysis on the basis of ...
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Topology optimization has been evolved into a very efficient conceptual design tool and has been utilized into design engineering processes. Traditional topology optimization has been using homogenization method and o...
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The explosion of storage media size and bandwidth has led to huge image databases. Methods are needed to find a particular image based on a crude description by the user. Keywording is not only tedious, but also subje...
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ISBN:
(纸本)1581135556
The explosion of storage media size and bandwidth has led to huge image databases. Methods are needed to find a particular image based on a crude description by the user. Keywording is not only tedious, but also subjective and therefore often incorrect. Available visual query systems have different properties, and are mostly based on some image transformation. An alternative visual query system is introduced, which finds an image similar to a user drawn sketch, or to any other reference image. A descriptor is created for each image in the database, and for the query image. Descriptors are compared in order to find the best matches. Descriptors are computed by inserting a limited number of quasi-random rectangles in the image, and computing the average colors of the rectangles. Furthermore, a reduced color histogram is computed and stored in the descriptor. The difference between descriptors is calculated as the weighted average of CIE LUV differences between corresponding rectangles. Using the Contrast Sensitivity Function this average is adapted to the users perception. The metric used for comparing images operates in the original image space, which makes the whole algorithm intuitive and easy to understand, and enables the comparison of images sections, as well. Copyright 2002 ACM.
Methods for mobile robot localization that use eigenspaces of panoramic snapshots of the environment are in general sensitive to changes in the illumination of the environment. Therefore, we propose an approach which ...
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Methods for mobile robot localization that use eigen spaces of panoramic snapshots of the environment are in general sensitive to changes in the illumination of the environment. Therefore, we propose an approach which...
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