Efficient dynamic language for technical computing

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 56-60).Dynamic programming languages have become popular for scientific computing. They are generally considered highly productive, but lacking in performance. This thesis presents a new dynamic language for technical computing, designed for performance from the beginning by adapting and extending modem programming language techniques. A design based on generic functions and a rich type system simultaneously enables an expressive programming model and successful type inference, leading to good performance for a wide range of programs. In our system, more behavior can be defined in libraries and user code, allowing our infrastructure to be shared across disciplines.by Jeffrey Werner Bezanson.S.M

Stylistic atructures: a computational approach to text classification

The problem of authorship attribution has received attention both in the academic world (e.g. did Shakespeare or Marlowe write Edward III?) and outside (e.g. is this confession really the words of the accused or was it made up by someone else?). Previous studies by statisticians and literary scholars have sought "verbal habits" that characterize particular authors consistently. By and large, this has meant looking for distinctive rates of usage of specific marker words -- as in the classic study by Mosteller and Wallace of the Federalist Papers. The present study is based on the premiss that authorship attribution is just one type of text classification and that advances in this area can be made by applying and adapting techniques from the field of machine learning. Five different trainable text-classification systems are described, which differ from current stylometric practice in a number of ways, in particular by using a wider variety of marker patterns than customary and by seeking such markers automatically, without being told what to look for. A comparison of the strengths and weaknesses of these systems, when tested on a representative range of text-classification problems, confirms the importance of paying more attention than usual to alternative methods of representing distinctive differences between types of text. The thesis concludes with suggestions on how to make further progress towards the goal of a fully automatic, trainable text-classification system

Stylistic atructures: a computational approach to text classification

The problem of authorship attribution has received attention both in the academic world (e.g. did Shakespeare or Marlowe write Edward III?) and outside (e.g. is this confession really the words of the accused or was it made up by someone else?). Previous studies by statisticians and literary scholars have sought "verbal habits" that characterize particular authors consistently. By and large, this has meant looking for distinctive rates of usage of specific marker words -- as in the classic study by Mosteller and Wallace of the Federalist Papers. The present study is based on the premiss that authorship attribution is just one type of text classification and that advances in this area can be made by applying and adapting techniques from the field of machine learning. Five different trainable text-classification systems are described, which differ from current stylometric practice in a number of ways, in particular by using a wider variety of marker patterns than customary and by seeking such markers automatically, without being told what to look for. A comparison of the strengths and weaknesses of these systems, when tested on a representative range of text-classification problems, confirms the importance of paying more attention than usual to alternative methods of representing distinctive differences between types of text. The thesis concludes with suggestions on how to make further progress towards the goal of a fully automatic, trainable text-classification system

The social structure and behaviour of Western Lowland gorillas (Gorilla gorilla gorilla) at Mbeli Bai, Republic of Congo

Most of what we know of the socioecology and behaviour of gorillas comes from studies of mountain gorillas (Gorilla beringei beringei), despite their representing less than 1% of all gorillas in the wild. Western lowland gorillas (Gorilla gorilla gorilla) have received far less research effort, and difficulties in habituation have led previous studies to rely heavily on indirect trail evidence. This has prevented any in-depth comparison of social structure and behaviour between species. The discovery of swampy clearings frequented by western lowland gorillas in northern Congo has offered the first opportunity to obtain accurate demographic and behavioural data. This thesis reports on 6273 hours of observer presence at Mbeli Bai, which yielded 1681 hours of direct gorilla observation. Most data come from a population of 13 groups and 7 solitary silverbacks. Group size ranged from 2 to 16 (mean = 8.4, SD 4.3) which does not differ significantly from data published on most other populations. Female natal and secondary transfer were recorded, and male emigration from the natal group appeared universal (no multi-silverback groups were recorded). No evidence of sub-grouping or a fission-fusion grouping pattern was found. During intra-group interactions, no evidence was recorded of female philopatry, and silverbacks herded and intimidated females (especially new immigrants) to prevent emigration. Inter-unit interactions took place on only 42% of shared bai-use occasions, and levels of silverback agonism were much lower than in mountain gorillas, with peaceful mingling of groups recorded. Display behaviour was common, and two previously unrecorded agonistic displays (the splash display and the crest display) are described. No contact aggression between silverbacks was observed but evidence of wounding sustained in the forest suggests that the bai environment may inhibit such aggression. High visibility and the ease of silverback 'policing' are thought to create an unusually tolerant social dynamic, and as such, frequencies of certain social behaviours should probably be viewed as site-specific. The thesis offers the fullest account of western gorilla social structure and behaviour to date. Long-term monitoring of life history variables, if continued, will provide an unparalleled opportunity to understand the effects of habitat and food availability and more stochastic influences on western gorilla social structure, fitness, and survival

THE COMPUTATION OF VERB-ARGUMENT RELATIONS IN ONLINE SENTENCE COMPREHENSION

Understanding how verbs are related to their arguments in real time is critical to building a theory of online language comprehension. This dissertation investigates the incremental processing of verb-argument relations with three interrelated approaches that use the event-related potential (ERP) methodology. First, although previous studies on verb-argument computations have mainly focused on relating nouns to simple events denoted by a simple verb, here I show by investigating compound verbs I can dissociate the timing of the subcomputations involved in argument role assignment. A set of ERP experiments in Mandarin comparing the processing of resultative compounds (Kid bit-broke lip: the kid bit his lip such that it broke) and coordinate compounds (Store owner hit-scolded employee: the store owner hit and scolded an employee) provides evidence for processing delays associated with verbs instantiating the causality relation (breaking-BY-biting) relative to the coordinate relation (hitting-AND-scolding). Second, I develop an extension of classic ERP work on the detection of argument role-reversals (the millionaire that the servant fired) that allows me to determine the temporal stages by which argument relations are computed, from argument identification to thematic roles. Our evidence supports a three-stage model where an initial word association stage is followed by a second stage where arguments of a verb are identified, and only at a later stage does the parser start to consider argument roles. Lastly, I investigate the extent to which native language (L1) subcategorization knowledge can interfere with second language (L2) processing of verb-argument relations, by examining the ERP responses to sentences with verbs that have mismatched subcategorization constraints in L1 Mandarin and L2 English (“My sister listened the music”). The results support my hypothesis that L1 subcategorization knowledge is difficult for L2 speakers to override online, as they show some sensitivity to subcategorization violations in offline responses but not in ERPs. These data indicate that computing verb-argument relations requires accessing lexical syntax, which is vulnerable to L1 interference in L2. Together, these three ERP studies allow us to begin to put together a full model of the sub-processes by which verb-argument relations are constructed in real time in L1 and L2

Dog-friendly workplaces : what works, what does not, and what lessons have been learned

There has been an exponential growth in companion dog ownership in the UK, both at a societal level and within the working population. The recent global pandemic caused a seismic shift in how people live and work, acting as a catalyst for the adoption of new flexible working practices that employees are reluctant to give up, such as working alongside their pets. While some attention has been given to the pros and cons of dog-friendly workplaces, evidence has not kept pace with changes, despite numerous calls for more research. This thesis consists of two papers: a systematic literature review and an empirical study. The first study of this thesis is a systematic literature review of published research pertaining to the intersection of companion dogs and organisational life. The aim of this review is to understand the current state of research on the effects of companion dogs on employees and the workplace. No known systematic literature review has been conducted in this area, despite several calls for research, although various narrative reviews have reported on the phenomenon. A limited number of studies were found in this area, with only nine identified studies meeting the inclusion criteria. The findings indicate promising positive consequences for companion dog owners and, in some cases, their colleagues, in terms of well-being levels, work engagement, commitment, and quality of life. Additionally, there is evidence that pet-friendly practices can serve as a mechanism to signal organisational values and culture. However, further research is needed here, preferably using a longitudinal approach with objective measures to increase confidence in the findings. Methodological limitations and contextual factors, such as the COVID-19 pandemic, hindered the robustness and replicability of the research. Implications for practice are discussed alongside suggestions for future research. The second study of this thesis addresses some of the gaps identified in the systematic literature review and seeks to answer what works, what does not, and what lessons can be learned about pet-friendly offices in a post-pandemic context. A qualitative study was adopted, using semi-structured interviews with 14 participants who had worked in companion dog-friendly offices. Participants included dog owners, non-dog owners, and subject matter expert groups from targeted backgrounds. Reflexive thematic analysis yielded six themes: first, the psychosocial impact of dog presence; second, the need for organisational congruence, in terms of having a dog-friendly office status; third, power dynamics engendered by dog-friendly offices, highlighting the ethical need to identify and manage stakeholders impacted by the decision to become a dog-friendly office; fourth, presentation to the outside world, understanding that pet-friendly practices are a mechanism for communicating organisational values, person-environment fit and a readiness to support practices which support work adjustments; fifth, continuous responsibility, an antecedent for sustainable practices, considering both human and non-human agency; and sixth, forethoughts and expectations – recognising the importance of agreeing with and adhering to clear expectations and consequences, mitigating risks through careful planning with subject-matter experts and workforce representatives. This thesis advances understanding of what employees expect from their organisations in terms of flexible working and work-life integration, with a particular focus on the opportunities for working in the presence of companion dogs. Furthermore, it builds on previous work highlighting the need for more research into how those who have implemented pet-friendly practices have overcome perceived problems. It also addresses the call for guidance to be developed by multidisciplinary teams. The thesis provides several avenues for future research. It outlines a conceptual framework for decision-makers and encourages future researchers to test the model’s utility. It also lays the foundation for the development of a toolkit intended to assist decision-makers in determining the feasibility of becoming a companion dog-friendly offic

Valuing disorder: perspectives on radical contingency in modern society

This thesis explores the relationship between social and individual forms of ordering social life on one hand, and the emergence of a number of ‘spheres’ of disorder in the experience of life on the other. In modern society such evidence of disorder can only be characterised in terms that reinforce the negative or formless experience of the human confrontations with disorder. Manifestations of radical contingency (taken as the cognitive residue of such disorder) in experience are thus contrasted with the progress and limits of reason and desire (which create the ‘valuable’ part of life), and these are further examined within a language of being that establishes the discordant nature of the relationship. It is argued that reason and desire, in creating value, always construct an edifice of social and personal expectation that is justified on the basis of the reliability of causal relations between phenomena in lived experience, and in so doing ‘make’ an objective and orderly social world. Several notions central to an understanding of the accumulation of categories of being in modern society are examined as the positive expression of the conditions of autonomous action, and thus as crucial determinants of value and identity. The central relationship is further investigated through the elaboration of three negative categories of experience, which are seen to contain individual and social forms of action that forcefully remove, or contradict order and autonomous freedom as it is here defined. The thesis is therefore divided into three parts. Part 1 examines the loss of autonomy through gambling, and specifically through the singular experience of the wager, which is seen to be an intensification of the motion that constitutes life, but that boldly refuses to be contained, as rational autonomy would dictate. Part 2 deals with the atomisation of knowledge and experience in modern society, looking specifically at instances of ‘non-representational’ art of the twentieth century as the residue of developments that had as a positive aim the refinement of experience. Part 3 deals with the material exclusion of various kinds of garbage resulting from both social and technological progress, and from the emergence of a multiplicity of opportunities for the establishment of self-identity that are seen as both a product of dividing the world of experience into ever smaller categories (i.e., the refinement of the ‘objective’ world) and of the subjective relationship between the individual in modern society and the world of objects