An orientation of an undirected graph is a choice of direction for each of its edges. An orientation is called ideal with respect to a given set of pairs of vertices if it does not increase the shortest-path distances between the members of any of the pairs. A polynomial-time algorithm is given for constructing an ideal orientation with respect to two given pairs and any positive edge-lengths, ...

17 graph. The cuts of G are the minimal dependent sets of a matroid T ? (G) on the edge set E. A matroid T is cographic if there exists some graph G such that T is isomorphic to the cut matroid T ? (G). Every cographic matroid is representable over any eld 18]. Therefore if an access structure A has a cographic appropriate matroid, then A is universally ideal. Unlike graphic matroids, we do not...

Let G denote a finite simple graph with edge ideal I(G). Letting I(G) denote the Alexander dual of I(G), we show that a description of the induced cycles of G of odd length is encoded in the associated primes of (I(G)). This result forms the basis for an algorithm to detect all the odd induced cycles of a graph via ideal operations, e.g., intersections, products, and colon operations. Moreover,...

Let IA be the toric ideal of a homogeneous normal configuration A ⊂ Z . We prove that IA is generated by circuits if and only if each unbalanced circuit of IA has a connector which is a linear combination of circuits with a square-free term. In particular, if each circuit of IA with non-square-free terms is balanced, then IA is generated by circuits. As a consequence we prove that the toric ide...

X-ray absorption spectroscopy and vacuum ultra-violet spectroscopic ellipsometry are used to study the electronic structure of complex oxides comprised of mixed TM/TM and TM/RE oxides. Experimental spectra for HfTiO4 and Gd(Dy)ScO3 indicate multiple d-state features in the O K1 edge. These are compared with the empirical models for atomic d-state mixing. It is concluded that a mean field, virtu...

The logic construction of a double-edge-triggered (DET) flip-flop, which can receive input signal at two levels of the clock, is analyzed and a new circuit design of CMOS DET flip-flop is proposed. Simulation using SPICE and a 1μ technology shows that this DET flip-flop has ideal logic functionality, a simpler structure, lower delay time, and higher maximum data rate compared to other existing ...

An edge-localized mode (ELM) H-mode regime, supported by electron cyclotron heating, has been successfully established in a "snowflake" (second-order null) divertor configuration for the first time in the TCV tokamak. This regime exhibits 2 to 3 times lower ELM frequency and 20%-30% increased normalized ELM energy (ΔWELM/Wp) compared to an identically shaped, conventional single-null diverted H...

We study the topology of the lcm-lattice of edge ideals and derive upper bounds on the Castelnuovo-Mumford regularity of the ideals. In this context it is natural to restrict to the family of graphs with no induced 4-cycle in their complement. Using the above method we obtain sharp upper bounds on the regularity when the complement is a chordal graph, or a cycle, or when the original graph is c...

This paper introduces two algorithms for enhancing image resolution from an image sequence. The “image-based” approach presumes that the images were taken under the same illumination conditions and uses the intensity information provided by the image sequence to construct the high-resolution image. This ideal, however, is almost always not true when the illumination varies. The “edge-based” app...

The XDD beamline (http://ssls.nus.edu.sg/facility/beamlines/xdd/xdd.htm) at SSLS delivers a tunable monochromatized photon source with high resolution in a wide energy range (2.3-10 keV). This hard x-ray light source is ideal for diffractometry, fluorescence detection and absorption spectroscopy, especially the study of XAFS (x-ray absorption fine structure) and XANES ( X-ray Absorption Near Ed...