2275334
On strong 1-factors and Hamilton weights of cubic graphs
Abstract A 1-factor M of a cubic graph G is strong if |M∩T|=1 for each 3-edge-cut T of G . It is proved in this paper that a cubic graph G has precisely three strong 1-factors if and only if the graph can be obtained from K 4 via a series of △↔Y operations. Consequently, the graph G admits a Hamilton weight and is uniquely edge-3-colorable.
17466332
Nowhere-zero 3-flows in products of graphs
A graph G is an odd-circuit tree if every block of G is an odd length circuit. It is proved in this paper that the product of every pair of graphs G and H admits a nowhere-zero 3-flow unless G is an odd-circuit tree and H has a bridge. This theorem is a partial result to the Tutte’s 3-flow conjecture and generalizes a result by Imrich and Skrekovski [7] that the product of two bipartite graphs admits a nowhere-zero 3-flow. A byproduct of this theorem is that every bridgeless Cayley graph G 1⁄4 Cayð ;SÞ on an abelian group with a minimal generating set S admits a nowhere-zero 3-flow except for odd prisms. 2005 Wiley Periodicals, Inc. J Graph Theory 50: 79–89, 2005
11462933
On flows in bidirected graphs
Bouchet conjectured that every bidirected graph which admits a nowhere-zero bidirected flow will admit a nowhere-zero bidirected 6-flow [A. Bouchet, Nowhere-zero integer flows on a bidirected graph, J. Combin. Theory Ser. B 34 (1983) 279-292]. He proved that this conjecture is true with 6 replaced by 216. Zyka proved in his Ph.D dissertation that it is true with 6 replaced by 30. Khelladi proved it is true with 6 replaced with 18 for 4-connected graphs [A. Khelladi, Nowhere-zero integer chains and flows in bidirected graphs, J. Combin. Theory Ser. B 43 (1987) 95-115]. In this paper, we prove that Bouchet's conjecture is true for 6-edge connected bidirected graphs.
13303898
Chords of longest circuits in 3-connected graphs
Thomassen conjectured that every longest circuit of a 3-connected graph has a chord. The conjecture is verified in this paper for projective planar graphs with minimum degree at least 4.
46565546
Arc-disjoint circuits in digraphs
36530209
Determination of the star valency of a graph
The star valency of a graph G is the minimum, over all star decompositions π, of the maximum number of elements in π incident with a vertex. The maximum average degree of G, denoted by dmax-ave(G), is the maximum average degree of all subgraphs of G. In this paper, we prove that the star valency of G is either ⌈dmax-ave(G)/2⌉ or ⌈dmax-ave(G)/2⌉ + 1, and provide a polynomial time algorithm for determining the star valency of a graph.
5200887
Damage pattern mining in hurricane image databases
We present a damage pattern mining framework for hurricane data on residential houses using aerial photographs with 1:3000 based scale. The vertical photographs are normally collected for an overview of a disaster area or for more detailed assessment. Damage on roof, especially for shingles torn off, is expected to be discovered in a more efficient and automatic way instead of going through the high-resolution aerial photograph for numerous details. The discovered damage patterns can then be used for hurricane damage assessment and impacts on different geographical areas. Our methodology is: (1) applying a novel and effective segmentation method on each residential house on the aerial photograph of one community, (2) using the segmentation results to obtain a set of indexing parameters for each house representing the damage level of roof cladding as well as the patterns of damage, (3) using these parameters to select several templates representing the damage patterns so that users can issue query-by-example (QBE) queries. The proposed segmentation method is an unsupervised simultaneous partition and class parameter estimation algorithm that considers the problem of segmentation as a joint estimation of the partition and class parameter variables. By utilizing this segmentation method, the indexing parameters can be obtained automatically. The QBE capability can assist in finding similar damage patterns on the roof of the residential houses in different locations in the image databases. Experiments based on the aerial photographs of Hurricane Andrew in 1992 are conducted and analyzed to show the effectiveness of the proposed hurricane damage pattern mining framework.
14923326
Co-histogram and Image Degradation Evaluation
The tool for image degradation evaluation addressed in this paper is called co-histogram, which is a statistic graph generated by counting the corresponding pixel pairs of two images. The graph is a two-dimensional joint probability distribution of the two images. A co-histogram shows how the pixels are distributed among combinations of two image pixel values. By means of co-histogram, we can have a visual understanding of PSNR, and the symmetry of a co-histogram is also significant for objective evaluation of image degradation. Our experiments with image degradation models of image compression, convolution blurring and geometric distortion perform the importance of the co-histogram.
10838244
Streaming SMIL Presentations via a Multimedia Semantic Model
The Synchronized Multimedia Integration Language (SMIL) allows Web designers to design complicated and vivid multimedia presentations in a declarative manner. In this paper, an abstract semantic model called Multimedia Augmented Transition Network (MATN) is used to model the conceptual structure of SMIL, as well as the temporal relations and synchronization control. The advantages of using the MATN model are its simplicity and ease of modification (scalability). Users can easily generate their favorite multimedia presentations using MATNs and render them using the SMIL players. Since the SMIL specification is quite new to the Internet society, the functionality of the players is limited, i.e., they often acquire proprietary platforms or cannot deal with MPEG or RTP media objects. Another contribution of this paper is to propose a novel architecture based on Java JMF technology for tackling with such constraints.
2983275
The interrelation of TCP responsiveness and smoothness in heterogeneous networks
TCP(/spl alpha/,/spl beta/) protocols trade the congestion window increase value /spl alpha/ for the decrease ratio /spl beta/, to generate smoother traffic patterns and to maintain a friendly behavior. We study the design assumptions of TCP(/spl alpha/,/spl beta/) protocols and discuss the impact of equation-based modulation of /spl alpha/ and /spl beta/ on application efficiency. We confirm experimentally that, in general, smoothness and responsiveness constitute a tradeoff; however, we uncover undesirable dynamics of the protocols when the network or flow characteristics do not follow a prescribed and static behavior. For example, we show that smooth backward adjustments confine the protocol's capability to exploit resources that become available rapidly, and embarrass the fair and efficient growth of incoming flows. Furthermore, we show that in the context of wireless networks with high error rate, a low /spl alpha/ dictates a conservative behavior that degrades the protocol performance with both delay-tolerant and delay-sensitive applications; and in the context of high contention of heterogeneous flows, a low /spl alpha/ does not contribute to efficiency and friendliness.
10875476
Affinity relation discovery in image database clustering and content-based retrieval
In this paper, we propose a unified framework, called <i>Markov Model Mediator</i> (MMM), to facilitate image database clustering and to improve the query performance. The structure of the MMM framework consists of two hierarchical levels: local MMMs and integrated MMMs, which model the affinity relations among the images within a single image database and within a set of image databases, respectively, via an effective data mining process. The effectiveness and efficiency of the MMM framework for database clustering and image retrieval are demonstrated over a set of image databases which contain various numbers of images with different dimensions and concept categories.