7439709
2-Arc-transitive regular covers of complete graphs having the covering transformation group Z3p
A family of 2-arc-transitive regular covers of a complete graph is investigated. In this paper, we classify all such covering graphs satisfying the following two properties: (1) the covering transformation group is isomorphic to the elementary abelian p-group Zp3, and (2) the group of fiber-preserving automorphisms acts 2-arc-transitively. As a result, new infinite families of 2-arc-transitive graphs are constructed.
43124802
On the Isomorphisms of Cayley Graphs of Abelian Groups
Let G be a finite group, S a subset of G\{1}, and let Cay (G, S) denote the Cayley digraph of G with respect to S. If, for any subset T of G\{1}, Cay(G, S) ≅ Cay(G, T) implies that Sα = T for some α ∈ Aut(G), then S is called a CI-subset. The group G is called a CIM-group if for any minimal generating subset S of G, S ∪ S-1 is a CI-subset. In this paper, CIM-abelian groups are characterized.
206570343
Vertex-Primitive Graphs of Order a Product of Two Distinct Primes
Abstract Let k and p be odd primes with k p . All vertex-primitive graphs of order kp are classified, and those which are symmetric, or are edge-transitive but not symmetric. or are not Cayley graphs are identified. In addition, a classification is given of all vertex-primitive, edge-transitive lantisymmetric) directed graphs or order kp . The classification of the vertex-primitive symmetric graphs of order kp is used by the authors and others to complete the classification of symmetric graphs or order kp . The classification of the vertex-primitive non-Cayley graphs of order kp is used by B.D. McKay and the first author in an investigation of vertex-transitive non-Cayley graphs.
29378412
Vertex-primitive digraphs of prime-power order are hamiltonian
Abstract Witte [6] proved that every connected Cayley digraph of a p -group is hamiltonian. In this note we generalize Witte's result to connected vertex-primitive digraphs of prime-power order; namely, we prove that every connected vertex-primitive digraph of prime-power order is hamiltonian.
15417765
The proof of a conjecture of Bouabdallah and Sotteau
Let G be a connected graph of order n. A routing in G is a set of n(n 1) fixed paths for all ordered pairs of vertices of G. The edge-forwarding index of G, (G), is the minimum of the maximum number of paths specified by a routing passing through any edge of G taken over all routings in G, and ,n is the minimum of (G) taken over all graphs of order n with maximum degree at most . To determine n 2p 1,n for 4p 2p/3 1 ≤ n ≤ 6p, A. Bouabdallah and D. Sotteau proposed the following conjecture in [On the edge forwarding index problem for small graphs, Networks 23 (1993), 249–255]. The set 3 {1, 2, . . . , (4p)/3} can be partitioned into 2p pairs plus singletons such that the set of differences of the pairs is the set 2 {1, 2, . . . , p}. This article gives a proof of this conjecture and determines that n 2p 1,n is equal to 5 if 4p 2p/3 1 ≤ n ≤ 6p and to 8 if 3p p/3 1 ≤ n ≤ 3p (3p)/5 for any p ≥ 2. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 292–296 2004
13407089
Event detection and period extraction using multi-scale symmetry and entropy
We present a system for detecting discrete periodic events over a short interval and in the presence of interference. In the first stage symmetries are identified using scale-space representation. This process detects signal events with a low signal-to-noise ratio but has the potential to introduce a number of false responses. This process is followed by an entropy-based algorithm that can robustly extract periodicities from a set of observed discrete events in the presence of a large number of false alarms. The event detection and period extraction processes have a low computational cost and can extract signal periodicity after a short observation time. This scheme was evaluated against four previously reported methods. Results demonstrate that the period extraction algorithm presented here is more reliable than three of the previously reported algorithms. The reliability of the algorithm presented here was similar to that of the fourth method but the computational cost was much less.
16235334
Illumination-Invariant Motion Detection Using Colour Mixture Models
This paper tackles the problem of robust change detection in image sequences from static cameras. Motion cues are detected using frame differencing with an adaptive background estimation modelled by a mixture of Gaussians. Illumination invariance and elimination or detection of shadows is achieved by using a colour chromaticity representation of the image data. The combination of the colourand intensity-based models results in some promising applications.
7639532
Fault diameter of Cartesian product graphs
The (k-1)-fault diameter D"k(G) of a k-connected graph G is the maximum diameter of G-F for any F@?V(G) with |F|=1 for i=1,2.
7022714
Simulating a $2M Commercial Server on a $2K PC
As dependence on database management systems and Web servers increases, so does the need for them to run reliably and efficiently-goals that rigorous simulations can help achieve. Execution-driven simulation models system hardware. These simulations capture actual program behavior and detailed system interactions. The authors have developed a simulation methodology that uses multiple simulations, pays careful attention to the effects of scaling on workload behavior, and extends Virtutech AB's Simics full system functional simulator with detailed timing models. The Wisconsin Commercial Workload Suite contains scaled and tuned benchmarks for multiprocessor servers, enabling full-system simulations to run on the PCs that are routinely available to researchers.