Spl Mscr Research Articles

Augmented ring networks

We study four augmentations of ring networks which are intended to enhance a ring's efficiency as a communication medium significantly, while increasing its structural complexity only modestly. Chordal rings add shortcut edges, which can be viewed as chords, to the ring. Express rings are chordal rings whose chords are routed outside the ring. Multirings append subsidiary rings to edges of a ring and, recursively, to edges of appended subrings. Hierarchical ring networks (HRN's) append subsidiary rings to nodes of a ring and, recursively, to nodes of appended subrings. We show that these four modes of augmentation are very closely related: 1) Planar chordal rings, planar express rings, and multirings are topologically equivalent families of networks with the cutwidth of an express ring translating into the tree depth of its isomorphic multiring and vice versa. 2) Every depth-d HRN is a spanning subgraph of a depth-(2d-1) multiring. 3) Every depth-d multiring /spl Mscr/ can be embedded into a d-dimensional mesh with dilation 3 in such a way that some node of /spl Mscr/ resides at a corner of the mesh. 4) Every depth-d HRN /spl Hscr/ can be embedded into a d-dimensional mesh with dilation 2 in such a way that some node of /spl Hscr/ resides at a corner of the mesh. In addition to demonstrating that these four augmented ring networks are grid graphs, our embedding results afford us close bounds on how much decrease in diameter is achievable for a given increase in structural complexity for the networks. Specifically, we derive upper and lower bounds on the optimal diameters of N-node depth-d multirings and HRN's that are asymptotically tight for large N and d.

A deductive object-oriented database system for situated inference in law

Deductive object-oriented databases and situation theory are two important areas of research in the fields of databases and of linguistics. "AI and law" is a new field attracting both AI researchers and legal practitioners. Our research brings together the former two fields with the aim of designing knowledge applications in the latter. This is achieved through a formal model for legal reasoning, /spl Sscr//spl Mscr/ ("Situation-theoretic Model"), and a deductive object-oriented database system, /spl Qscr//spl Uscr//spl Iscr//spl Xscr//spl Oscr//spl Tscr//spl Escr/. The purpose of this paper is to introduce the key features of this formal model, based on situation theory, and to describe how this database system can implement this abstract model for complex legal reasoning applications. Concrete examples from legal precedents are used to illustrate these advanced features.

Magnetic hysteresis loops and fast relaxation of vortex lattice in YBaCuO single crystal

The magnetic moment values /spl Mscr/ at conventional magnetic moment relaxation at constant magnetic field and in magnetic hysteresis loop experiment are directly related and are the same if /spl musub 0/(d/spl Mscrdt)/sub CR/=/spl chisub 0(dB/sub edt)/sub MHL/. Dependencies of /spl Mscr/(dB/sub edt) measured by vibrating sample magnetometer on YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta single crystals at temperatures ranging from 2.5 K to 54 K are analyzed. Activation energy U/sub e/=-kT[ln(dB/sub edt)-C] vs. /spl Mscr/ is plotted with parameter C being adjusted to form a smooth curve. In this way the critical sweep rate (dB/sub edt)c=exp(C) corresponding to the critical state U/sub e/(/spl Mscrsub c/)=0 is determined. A detailed analysis shows that In(dB/sub edt)c increases approximately linearly with temperature. This dependence can be removed by scaling the activation energy by a temperature dependent factor. At temperatures below 5 K departure from the thermally activated relaxation occurs, the origin of which can be the quantum tunnelling effect.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>