206571175
A New Bound on the Cyclic Chromatic Number
In 1969, Ore and Plummer defined an angular coloring as a natural extension of the Four Color Problem: a face coloring of a plane graph where faces meeting even at a vertex must have distinct colors. A natural lower bound is the maximum degree ? of the graph. Some graphs require ?32?? colors in an angular coloring. Ore and Plummer gave an upper bound of 2?, which was improved to ?95?? by the authors with Borodin. This article gives a new upper bound of ?59?? on the angular chromatic number. The cyclic chromatic number is the equivalent dual vertex coloring problem.
22657577
On cyclic colorings and their generalizations
Abstract A cyclic coloring is a vertex coloring such that vertices in a face receive different colors. Let Δ be the maximum face degree of a graph. This article shows that plane graphs have cyclic 9 5 Δ -colorings, improving results of Ore and Plummer, and of Borodin. The result is mainly a corollary of a best-possible upper bound on the minimum cyclic degree of a vertex of a plane graph in terms of its maximum face degree. The proof also yields results on the projective plane, as well as for d-diagonal colorings. Also, it is shown that plane graphs with Δ=5 have cyclic 8-colorings. This result and also the 9 5 Δ result are not necessarily best possible.
41806675
On Diagonally 10-Coloring Plane Triangulations
This article shows that the vertices of a plane triangulation may be colored with 10 colors such that every pair of vertices has different colors if they are either adjacent or diagonal, that is, that they are not adjacent but are adjacent to two faces which share an edge. This improves a result of Borodin, who showed that 11 colors were sufficient. © 1996 John Wiley & Sons, Inc.
27555066
On the Edge Reconstruction of Graphs Embedded in Surfaces, III,
In this paper, we prove that if a connected graphGembeddable in a surface?of characteristic?(?) satisfies (1) the minimum degree ofG?5, (2) |V(G)|??43?(?), thenGis edge reconstructible. A direct consequence of the above result is that a triangulationGof a surface of characteristic?(?) is edge reconstructible if |V(G)|??43?(?).
38637293
On spanning trees and walks of low maximum degree
6315714
On the edge-reconstruction of graphs embedded in surfaces IV
In this paper, by applying the discharging method, we give simple proofs that (1) every n-vertex graph with minimum degree at least 3 and girth at least 5 that is embeddable in a surface Σ of Euler characteristic at least -n/8 is edge-reconstructible, and (2) every n-vertex graph with minimum degree at least 4 that is embeddable without faces of length at most 3 in a surface Σ of Euler characteristic at least -n/6 is edge-reconstructible.
15396012
Silicon Wafer Defect Extraction Based on Morphological Filter and Watershed Algorithm
Defect extraction techniques are studied regarding the silicon wafer surface defect. We design a new filter based on multiple structuring elements and suggest an improved marker-based and region merging watershed. To begin with, the filter which generalized close-opening and open-closing filter based on the morphological filter with multiple structuring elements is introduced to eliminate the noise and simplify the image and morphological gradient image while preserving the details. And then in order to reduce the over-segmentation of the watershed algorithm, this paper suggests an improved marker-based and region merging method, region average gray value and edge strength criterion is used in merging operation and has a good effect on segmentation. Finally, the improved watershed algorithm is applied to the filtered gradient image to get the defect contours. The experiments show that this method can eliminate the noises and extract accurately location and closed region contours, which lays a good foundation for defect feature extraction and selection.
15753558
Pseudo-surface based network camera smart control
Network camera is widely used in a lot of fields, such as remote monitoring, video conference. However, in almost network camera systems, the camera remote control is realized by using a remote controller or a personal computer with a crude user interface. This kind of control methods are not effective in the situation such as real time distance class where a smart operation is needed for the teacher. This article proposes a pseudo-surface based control method for network camera remote control. This method can improve the operativeness of the network camera control without using special devices other than a control computer. The effectiveness of this method was proven by a simulation system. In this article the principle of this method is described, and several examples of it are introduced.
18369572
Recursive Algorithms for a Novel Identification Criterion
A new identification criterion is concerned for disturbed system with color noise in this paper. The cost function considers both the errors between the actual outputs and the estimation result and the difference of each estimation error. Under this performance function, a new recursive algorithm DSCN (Disturbed System with Color Noise) is proposed. It could reduce the influence of noise in system identification, further decrease the prediction error. Several simulation examples are given to illustrate the method's anti-disturbance performance.
5668902
Optimal Spectrum Management in Multiuser Interference Channels
In this paper, we study the problem of continuous frequency optimal spectrum management in multiuser frequency selective interference channels. We assume that interference is treated as noise by the decoders, and separate encoding is applied. First, a simple pair-wise channel condition for frequency division multiple access schemes to achieve all Pareto optimal points of the rate region is derived. It enables fully distributed global optimal decision making on whether any two users should use orthogonal channels. Next, we present an analytical solution to finding the maximum sum-rate in two-user symmetric frequency flat channels. Generalizing this solution to frequency selective channels, a convex optimization is established that yields the global optimum. Finally, we show that our method generalizes to K-user (K ≥ 2) weighted sum-rate maximization in asymmetric frequency selective channels, and we transform this classic nonconvex optimization to an equivalent convex optimization in the primal domain.
45238028
Improvement of the Damaged Thermowell of the Monju Fast-Breeder Reactor Based on Vibration Analysis
In December 1995, the thermowell in the secondary cooling system of the Japanese fast-breeder reactor Monju was damaged, resulting in a sodium leak. Sodium flow was thought to have produced a vibration in the thermowell that then caused high-cycle fatigue that eventually destroyed the thermowell. Using the finite element method, the natural frequency of the thermowell was found to be approximately 230 Hz, which is in the region of resonance of the fluid vibration. Next, in a theoretical study, the authors altered the position at which the diameter of the thermowell changes and examined the resulting natural frequencies. They also studied the effects of thickness and diameter on the natural frequency of the thermowell and examined the case for a truncated conical thermowell. The results indicate that production of a thermowell that is not affected by vibration due to resonance is possible. This paper recommends improved shapes for the thermowell.