6544638
Guaranteeing 2-manifold property for meshes
Meshes are the most commonly used objects in computer graphics. They generalize polyhedra by using non-planar faces. Modeling 2D manifold meshes with a simple user interface is an important problem in computer-aided geometric design. In this paper, we propose a conceptual framework for mesh modeling systems that guarantees topologically correct 2D manifolds. Our solution is based on graph rotation systems developed in topological graph theory. As an internal representation of meshes, we use a doubly-linked face list (DLFL). We have also developed a visual representation of the topology that provides a powerful tool for developing a user interface to manipulate the topology of the mesh.
2261180
Graph Ear Decompositions and Graph Embeddings
Ear decomposition of a graph has been extensively studied in relation to graph connectivity. In this paper, a connection of ear decomposition to graph embeddings is exhibited. It is shown that constructing a maximum-paired ear decomposition of a graph and constructing a maximum-genus embedding of the graph are polynomial-time equivalent. Applications of this connection are discussed.
5242879
Interactive rind modeling
In this paper, we describe a technique, with roots in topological graph theory, that we call rind modeling. It provides for the easy creation of surfaces resembling peeled and punctured rinds. We show how the method's two main steps of: 1) creation of a shell or crust like the rind of an orange, and 2) opening holes in the crust by punching or peeling can be encapsulated into a real time semi-automatic interactive algorithm. We include a number of worked examples, some by students in a first modeling course, that demonstrate the ease with which a large variety of intricate rind shapes can be created.
1021255
A minimal and complete set of operators for the development of robust manifold mesh modelers
In this paper, we identify a minimal and complete set of fundamental operators, which is necessary and sufficient for performing all homeomorphic and topological operations on 2- manifold mesh structures. Efficient algorithms are developed for the implementation of these operators. We also developed a set of powerful, user-friendly, and effective operators at the level of user-interface. Using these operators, we have developed a prototype system for robust, interactive, and user-friendly modeling of orientable 2-manifold meshes. Users of our system can perform a large set of homeomorphic and topological changes with these user-interface level operators. Our system is topologically robust in the sense that users will never create invalid 2-manifold mesh structure with these operators. In our system, the homeomorphic and topological surgery operations can be applied alternatively on 2-manifold meshes. With our system, users can blend surfaces, construct rinds, and open holes on these rind shapes. With our system, the shapes that look like solid, non-manifold, or 2-manifold with boundary can be manipulated. The system also provides automatic texture mapping during topology changes.
31382426
Strong Fault-Tolerance: Parallel Routing in Networks with Faults
A d-regular network G is strongly fault-tolerant if for any copy Gf of G with at most d - 2 faulty nodes, every pair of nonfaulty nodes u and v in Gf admits min{df(u), df (v)} node-disjoint paths in Gf from u to v, where df(u) and df(v) are the degrees of the nodes u and v in Gf. We show that popular network structures, such as hypercube and star networks, are strongly fault-tolerant. We develop efficient algorithms that construct the maximum number of node-disjoint paths of optimal or nearly optimal length in these networks with faulty nodes. Our algorithms are optimal in terms of their running time.
16331940
Optimal Parallel Routing in Star Networks
Star networks have recently been proposed as attractive alternatives to the popular hypercube for interconnecting processors on a parallel computer. In this paper, we present an efficient algorithm that constructs an optimal parallel routing in star networks. Our result improves previous results for the problem.
14245135
Automatic Correlation and Calibration of Noisy Sensor Readings Using Elite Genetic Algorithms
This paper explores an image processing application of optimization techniques which entails interpreting noisy sensor data. The application is a generalization of image correlation; we attempt to find the optimal gruence which matches two overlapping gray scale images corrupted with noise. Both tabu search and genetic algorithms are used to find the parameters which match the two images. A genetic algorithm approach using an elitist reproduction scheme is found to provide significantly superior results.
10853556
A robust watermarking method based on wavelet and Zernike transform
As watermarking is increasingly applied for a variety of applications, various properties of watermarks, such as how they respond to common signal transformations or deliberate attacks, have become important concerns. In this paper, we propose a new approach to embed a watermark that is to modify the block average in wavelet domain. If the watermarked image has been attacked by geometric ways, we can figure it out by Zernike transform and then retrieve it. Experiments prove that the method is not only robust to geometric attacks, but also to JPEG and Checkmark attacks.
15106066
The feature tree: visualizing feature tracking in distributed AMR datasets
We describe a feature extraction and tracking algorithm for AMR (adaptive mesh refinement) datasets that operates within a distributed computing environment. Because features can span multiple refinement levels and multiple processors, tracking must be performed across time, across levels, and across processors. The resulting visualization is represented as a "feature tree". A feature contains multiple parts corresponding to different levels of refinements. The feature tree allows a viewer to determine that a feature splits or merges at the next refinement level, and allows a viewer to extract and isolate a multilevel isosurface and watch how that surface changes over both time and space. The algorithm is implemented within a computational steering environment, which enables the visualization routines to operate on the data in-situ (while the simulation is ongoing).
26682479
Web-Based Collaborative Tools for Geospatial Data Exploration
Federal government agencies have collected large and highly complex federal statistical summaries and geo-reference data. Methods and tools for identifying patterns and uncovering multivariate relationships in the complex datasets have drawn attention in multiple fields. The approach we present here extends from and integrates perspectives from multiple fields, including exploratory data analysis (EDA), geovisualization, information visualization, and data mining. Important components of our research are supported by a NSF Digital Government grant (#99883451). Other support comes from a National Cancer Institute (NCI) contract. Our DG research is now being extended to develop comprehensive multivariate analysis methods and tools, through a grant from NCI (CA95949).
18417913
IT induction in the food service industry
As part of the business strategy in a competitive environment, for an organization to induct information technology (IT) appropriately, business process reengineering (BPR) must be conducted. We propose a process that incorporates both management information systems and strategic management concepts for the IT induction. First, we develop a business competition strategy based on Porter’s five competitive forces; second, using concepts developed in the field of information systems the business processes are reengineered to improve effectiveness and efficiency; and finally, IT strategy is developed to achieve these goals. A real‐life case in the food service industry is used to illustrate this process.