7478203
Parallel routing in hypercube networks with faulty nodes
The concept of strong fault-tolerance was introduced to characterize the property of parallel routing. A network G of degree d is said to be strongly fault-tolerant if with at most d-2 faulty nodes, any two nodes u and v in G are connected by min{deg/sub f/(u), deg/sub f/(v)} node-disjoint paths, where deg/sub f/ (u) and deg/sub f/ (v) are the numbers of non-faulty neighbors of the nodes u and v in G, respectively. We show that the hypercube networks are strongly fault-tolerant and develop an algorithm that constructs the maximum number of node-disjoint paths in a hypercube network with faults. Our algorithm is optimal in terms of time and length of node-disjoint paths.
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.
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.
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.
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.
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.
19801796
Multimedia Over IP For Thin Clients : Building A Collaborative Resource-Sharing Prototype
This paper describes the issues and the techniques of enabling multimedia applications with thin-client/server computing. A prototype of a video communication system based on H.323 family of ITU-T recommendations has been developed to demonstrate the efficient support to multimedia applications with a terminal server and thin clients in an IP-based thin-client computing environment. With the proposed architecture, a collaborative multi-user audio/video conference system is presented as an illustrative application. The collaborative multiuser audio/video conference system leverages the benefit of sharing common components among multiple conference terminals as well as increases their extensibility and ease of use. As a result, we can attain a balanced architecture that supports both centralized management of application softwares and distributed multimedia processing for I/O devices.
6409733
Routing in an Internet-scale network emulator
One of the primary challenges facing scalable network emulation and simulation is the overhead of storing network-wide routing tables or computing appropriate routes on a per-packet basis. We present an approach to routing table calculation and storage based on spanning tree construction that provides an order of magnitude reduction in routing table size for Internet-like topologies. In our approach, we maintain a variable number of spanning trees for a given topology and choose the path between two hosts in each tree, choosing the shortest. We also populate offline a negative cache of actual shortest paths for source-destination pairs - typically a few percent of the total - where the lookups result in sub-optimal routes. We have implemented our technique in a popular network emulator, ModelNet, and show that our enhanced version can emulate Internet topologies 10-100 times larger than previously possible.
8954904
Modification of the AdaBoost-based Detector for Partially Occluded Faces
While face detection seems a solved problem under general conditions, most state-of-the-art systems degrade rapidly when faces are partially occluded by other objects. This paper presents a solution to detect partially occluded faces by reasonably modifying the AdaBoost-based face detector. Our basic idea is that the weak classifiers in the AdaBoost-based face detector, each corresponding to a Haar-like feature, are inherently a patch-based model. Therefore, one can divide the whole face region into multiple patches, and map those weak classifiers to the patches. The weak classifiers belonging to each patch are re-formed to be a new classifier to determine if it is a valid face patch - without occlusion. Finally, we combine all of the valid face patches by assigning the patches with different weights to make the final decision whether the input subwindow is a face. The experimental results show that the proposed method is promising for the detection of occluded faces
8408042
The Rat Genome Database (RGD): developments towards a phenome database
The Rat Genome Database (RGD) (http://rgd.mcw.edu) aims to meet the needs of its community by providing genetic and genomic infrastructure while also annotating the strengths of rat research: biochemistry, nutrition, pharmacology and physiology. Here, we report on RGD's development towards creating a phenome database. Recent developments can be categorized into three groups. (i) Improved data collection and integration to match increased volume and biological scope of research. (ii) Knowledge representation augmented by the implementation of a new ontology and annotation system. (iii) The addition of quantitative trait loci data, from rat, mouse and human to our advanced comparative genomics tools, as well as the creation of new, and enhancement of existing, tools to enable users to efficiently browse and survey research data. The emphasis is on helping researchers find genes responsible for disease through the use of rat models. These improvements, combined with the genomic sequence of the rat, have led to a successful year at RGD with over two million page accesses that represent an over 4-fold increase in a year. Future plans call for increased annotation of biological information on the rat elucidated through its use as a model for human pathobiology. The continued development of toolsets will facilitate integration of these data into the context of rat genomic sequence, as well as allow comparisons of biological and genomic data with the human genomic sequence and of an increasing number of organisms.
15338297
Fast construction of overlay networks
An asynchronous algorithm is described for rapidly constructing an overlay network in a peer-to-peer system where all nodes can in principle communicate with each other directly through an underlying network, but each participating node initially has pointers to only a handful of other participants. The output of the mechanism is a linked list of all participants sorted by their identifiers, which can be used as a foundation for building various linear overlay networks such as Chord or skip graphs. Assuming the initial pointer graph is weakly-connected with maximum degree <i>d</i> and the length of a node identifier is <i>W</i>, the mechanism constructs a binary search tree of nodes of depth <i>O</i>(<i>W</i>) in expected <i>O</i>(<i>W</i> log <i>n</i>) time using expected <i>O</i>((<i>d</i>+<i>W</i>)<i>n</i> log <i>n</i>) messages of size <i>O</i>(<i>W</i>) each. Furthermore, the algorithm has low <i>contention</i>: at any time there are only <i>O</i>(<i>d</i>) undelivered messages for any given recipient. A lower bound of Ω(<i>d</i> + log <i>n</i>) is given for the running time of any procedure in a related synchronous model that yields a sorted list from a degree-<i>d</i> weakly-connected graph of <i>n</i> nodes. We conjecture that this lower bound is tight and could be attained by further improvements to our algorithms.