Thue's 1914 paper: a translation

This paper includes notes to accompany a reading of Thue's 1914 paper "Probleme uber Veranderungen von Zeichenreihen nach gegebenen Reglen", along with a translation of that paper. Thue's 1914 paper is mainly famous for proving an early example of an undecidable problem, cited prominently by Post. However, Post's paper principally makes use of the definition of Thue systems, described on the first two pages of Thue's paper, and does not depend on the more specific results in the remainder of Thue's paper. A closer study of the remaining parts of that paper highlight a number of important themes in the history of computing: the transition from algebra to formal language theory, the analysis of the "computational power" (in a pre-1936 sense) of rules, and the development of algorithms to generate rule-sets

Metamodel Instance Generation: A systematic literature review

Modelling and thus metamodelling have become increasingly important in Software Engineering through the use of Model Driven Engineering. In this paper we present a systematic literature review of instance generation techniques for metamodels, i.e. the process of automatically generating models from a given metamodel. We start by presenting a set of research questions that our review is intended to answer. We then identify the main topics that are related to metamodel instance generation techniques, and use these to initiate our literature search. This search resulted in the identification of 34 key papers in the area, and each of these is reviewed here and discussed in detail. The outcome is that we are able to identify a knowledge gap in this field, and we offer suggestions as to some potential directions for future research.Comment: 25 page

Warm Dark Haloes Accretion Histories and their Gravitational Signatures

We study clusters in Warm Dark Matter (WDM) models of a thermally produced dark matter particle $0.5$ keV in mass. We show that, despite clusters in WDM cosmologies having similar density profiles as their Cold Dark Matter (CDM) counterparts, the internal properties, such as the amount of substructure, shows marked differences. This result is surprising as clusters are at mass scales that are {\em a thousand times greater} than that at which structure formation is suppressed. WDM clusters gain significantly more mass via smooth accretion and contain fewer substructures than their CDM brethren. The higher smooth mass accretion results in subhaloes which are physically more extended and less dense. These fine-scale differences can be probed by strong gravitational lensing. We find, unexpectedly, that WDM clusters have {\em higher} lensing efficiencies than those in CDM cosmologies, contrary to the naive expectation that WDM clusters should be less efficient due to the fewer substructures they contain. Despite being less dense, the larger WDM subhaloes are more likely to have larger lensing cross-sections than CDM ones. Additionally, WDM subhaloes typically reside at larger distances, which radially stretches the critical lines associated with strong gravitational lensing, resulting in excess in the number of clusters with large radial cross-sections at the $\sim2\sigma$ level. Though lensing profile for an individual cluster vary significantly with the line-of-sight, the radial arc distribution based on a sample of $\gtrsim100$ clusters may prove to be the crucial test for the presence of WDM.Comment: 13 pages, 14 figures, submitted to MNRA

Thue's 1914 paper: a translation

This paper includes notes to accompany a reading of Thue's 1914 paper "Probleme uber Veranderungen von Zeichenreihen nach gegebenen Reglen", along with a translation of that paper. Thue's 1914 paper is mainly famous for proving an early example of an undecidable problem, cited prominently by Post. However, Post's paper principally makes use of the definition of Thue systems, described on the first two pages of Thue's paper, and does not depend on the more specific results in the remainder of Thue's paper. A closer study of the remaining parts of that paper highlight a number of important themes in the history of computing: the transition from algebra to formal language theory, the analysis of the "computational power" (in a pre-1936 sense) of rules, and the development of algorithms to generate rule-sets

Exploring Thue's 1914 paper on the transformation of strings according to given rules

Axel Thue's paper of 1914 on string rewriting was made famous by Emil Post when, in 1947, he proved the word problem for Thue systems to be undecidable. Yet, only the first two pages of Thue's paper are directly relevant to Post's work in 1947, and the remaining 30 pages seem to have been cast into the shade. Based on a recently completed translation of this paper, I hope to shed some light on the remaining part of this work, and to advocate its relevance for the history of computing. Thue's paper has been "passed by reference" into the history of computing, based mainly on a small section of that work. A closer study of the remaining parts of that paper highlight a number of important themes in the history of computing: the transition from algebra to formal language theory, the analysis of the "computational power" (in a pre-1936 sense) of rules, and the development of algorithms to generate rule-sets

Schenectadys New Deal: The WPA in the City of Schenectady

When President Roosevelt assumed office in March of 1933, he faced an unemployment rate of twenty-five percent, homelessness, and the malaise of a nation stuck in a deepening state of poverty. His solution, aimed at alleviating the circumstances resulting from the Great Depression, was to institute a series of economic programs known as the “New Deal.” Roosevelt proposed the creation of a variety of social welfare programs, including “work relief” that would provide government jobs for the unemployed. The best known program was the Works Progress Administration, or simply, the WPA, created in 1935. Through projects ranging from building roads and schools, constructing sewers and bridges, to the development of parks and playgrounds, the WPA provided much needed relief for the unemployed, and transformed the physical landscape of the nation. While significant research has been done on the New Deal and WPA’s impact on a national level, less has been done on the impact at the local level, and very little research has been conducted examining the WPA’s role and influence in the City of Schenectady. This thesis addresses that gap, and argues that the type of work performed by the WPA in Schenectady corresponded with state and national trends. In addition, attitudes in Schenectady toward work relief corresponded with state trends but diverged from national trends: nationally, Republicans generally opposed the WPA, while local Republicans found it politically advantageous to endorse the program

Exploring Thue's 1914 paper on the transformation of strings according to given rules

Axel Thue's paper of 1914 on string rewriting was made famous by Emil Post when, in 1947, he proved the word problem for Thue systems to be undecidable. Yet, only the first two pages of Thue's paper are directly relevant to Post's work in 1947, and the remaining 30 pages seem to have been cast into the shade. Based on a recently completed translation of this paper, I hope to shed some light on the remaining part of this work, and to advocate its relevance for the history of computing. Thue's paper has been "passed by reference" into the history of computing, based mainly on a small section of that work. A closer study of the remaining parts of that paper highlight a number of important themes in the history of computing: the transition from algebra to formal language theory, the analysis of the "computational power" (in a pre-1936 sense) of rules, and the development of algorithms to generate rule-sets