On finite complete rewriting systems and large subsemigroups

Let $S$ be a semigroup and $T$ be a subsemigroup of finite index in $S$ (that is, the set $S\setminus T$ is finite). The subsemigroup $T$ is also called a large subsemigroup of $S$. It is well known that if $T$ has a finite complete rewriting system then so does $S$. In this paper, we will prove the converse, that is, if $S$ has a finite complete rewriting system then so does $T$. Our proof is purely combinatorial and also constructive.Comment: We have made major changes to the paper and simplified most of the proof

Analytic provenance as constructs of behavioural markers for externalizing thinking processes in criminal intelligence analysis

Studying how analysts use interaction in visualization systems is an important part of evaluating how well these interactions support analysis needs, like generating insights or performing tasks. Analytic Provenance commonly known as interaction histories contains information about the sequence of choices that analysts make when exploring data or performing a task. This research work presents a compositional reductionist approach as a way of externalizing analyst’s thinking processes by using markers of analytical behaviour extracted from such interaction histories. Set of Behavioural Markers (BMs) have been identified through a workshop with domain experts and a systematic literature review to use them as cognitive attributes of imagination, insight, transparency, fluidity and rigour to enhance performance in criminal intelligence analysis. A low level semantic action sequence computation also has been proposed as a detection approach of identified BMs and found from computation that BMs can act as bridge between human cognition and computation through semantic interaction. This research work has addressed problems of existing qualitative experiments to extract these BMs through cognitive task analysis and found that the proposed computational technique can be a supplementary approach for validating experimental results

Ignition characterization of LOX/hydrocarbon propellants

The results of an evaluation of the ignition characteristics of the gaseous oxygen (Gox)/Ethanol propellant combination are presented. Ignition characterization was accomplished through the analysis, design, fabrication and testing of a spark initiated torch igniter and prototype 620 lbF thruster/igniter assembly. The igniter was tested over a chamber pressure range of 74 to 197 psia and mixture ratio range of 0.778 to 3.29. Cold (-92 to -165 F) and ambient (44 to 80 F) propellant temperatures were used. Spark igniter ignition limits and thruster steady state and pulse mode, performance, cooling and stability data are presented. Spark igniter ignition limits are presented in terms of cold flow pressure, ignition chamber diameter and mixture ratio. Thruster performance is presented in terms of vacuum specific impulse versus engine mixture ratio. Gox/Ethanol propellants were shown to be ignitable over a wide range of mixture ratios. Cold propellants were shown to have a minor effect on igniter ignition limits. Thruster pulse mode capability was demonstrated with multiple pulses of 0.08 sec duration and less

Interaction log and provenance for sensemaking

This paper describes two visual analytic tools designed to support sensemaking through the visualisation of interaction log and analytic provenance. The first tool, SensePath, aims to reduce the time required for the transcription and coding during qualitative analysis such as thematic analysis (making sense of the experiment data). The second tool, SenseMap, is designed to help online sensemaking with everyday tasks such as buying a digital camera. User evaluation leads to early insight of how the visualisation of interaction log and analytic provenance can help these sensemaking tasks

Interactive visualization for information analysis in medical diagnosis

This paper investigates to what extend the findings and solutions of information analysis in intelligence analysis can be applied and transferred into the medical diagnosis domains. Interactive visualization is proposed to address some of the problems faced by both domain. Its design issues related to selected common problems are then discussed in details. Finally, a visual sense making system INVISQUE is used as an example to illustrate how the interactive visualization can be used to support information analysis and medical diagnosis

Provenance for intelligence analysis using visual analytics.

In this paper we discuss various aspects in intelligence analysis relating to provenance and the new requirements resulting from the changed nature of terrorist activities. We propose a three-layer provenance model which relates the scope of provenance to the intelligence workflow and the idea of a ’provenance reasoning workspace’ for integrating provenance information into visual analytic tools

Regularities with random interactions in energy centroids defined by group symmetries

Regular structures generated by random interactions in energy centroids defined over irreducible representations (irreps) of some of the group symmetries of the interacting boson models $sd$IBM, $sdg$IBM, $sd$IBM-$T$ and $sd$IBM-$ST$ are studied by deriving trace propagations equations for the centroids. It is found that, with random interactions, the lowest and highest group irreps in general carry most of the probability for the corresponding centroids to be lowest in energy. This generalizes the result known earlier, via numerical diagonalization, for the more complicated fixed spin ($J$) centroids where simple trace propagation is not possible.Comment: 18 pages, 3 figure

Melt-growth dynamics in CdTe crystals

We use a new, quantum-mechanics-based bond-order potential (BOP) to reveal melt-growth dynamics and fine-scale defect formation mechanisms in CdTe crystals. Previous molecular dynamics simulations of semiconductors have shown qualitatively incorrect behavior due to the lack of an interatomic potential capable of predicting both crystalline growth and property trends of many transitional structures encountered during the melt $\rightarrow$ crystal transformation. Here we demonstrate successful molecular dynamics simulations of melt-growth in CdTe using a BOP that significantly improves over other potentials on property trends of different phases. Our simulations result in a detailed understanding of defect formation during the melt-growth process. Equally important, we show that the new BOP enables defect formation mechanisms to be studied at a scale level comparable to empirical molecular dynamics simulation methods with a fidelity level approaching quantum-mechanical method

Magnetic domain walls in constrained geometries

Magnetic domain walls have been studied in micrometer-sized Fe20Ni80 elements containing geometrical constrictions by spin-polarized scanning electron microscopy and numerical simulations. By controlling the constriction dimensions, the wall width can be tailored and the wall type modified. In particular, the width of a 180 degree Neel wall can be strongly reduced or increased by the constriction geometry compared with the wall in unconstrained systems.Comment: 4 pages, 6 figure