Reliable and safe autonomy for ground vehicles in unstructured environments

This thesis is concerned with the algorithms and systems that are required to enable safe autonomous operation of an unmanned ground vehicle (UGV) in an unstructured and unknown environment; one in which there is no speci c infrastructure to assist the vehicle autonomy and complete a priori information is not available. Under these conditions it is necessary for an autonomous system to perceive the surrounding environment, in order to perform safe and reliable control actions with respect to the context of the vehicle, its task and the world. Speci cally, exteroceptive sensors measure physical properties of the world. This information is interpreted to extract a higher level perception, then mapped to provide a consistent spatial context. This map of perceived information forms an integral part of the autonomous UGV (AUGV) control system architecture, therefore any perception or mapping errors reduce the reliability and safety of the system. Currently, commercially viable autonomous systems achieve the requisite level of reliability and safety by using strong structure within their operational environment. This permits the use of powerful assumptions about the world, which greatly simplify the perception requirements. For example, in an urban context, things that look approximately like roads are roads. In an indoor environment, vertical structure must be avoided and everything else is traversable. By contrast, when this structure is not available, little can be assumed and the burden on perception is very large. In these cases, reliability and safety must currently be provided by a tightly integrated human supervisor. The major contribution of this thesis is to provide a holistic approach to identify and mitigate the primary sources of error in typical AUGV sensor feedback systems (comprising perception and mapping), to promote reliability and safety. This includes an analysis of the geometric and temporal errors that occur in the coordinate transformations that are required for mapping and methods to minimise these errors in real systems. Interpretive errors are also studied and methods to mitigate them are presented. These methods combine information theoretic measures with multiple sensor modalities, to improve perceptive classi cation and provide sensor redundancy. The work in this thesis is implemented and tested on a real AUGV system, but the methods do not rely on any particular aspects of this vehicle. They are all generally and widely applicable. This thesis provides a rm base at a low level, from which continued research in autonomous reliability and safety at ever higher levels can be performed

Systems thinking, the Swiss Cheese Model and accident analysis: a comparative systemic analysis of the Grayrigg train derailment using the ATSB, AcciMap and STAMP models

The Swiss Cheese Model (SCM) is the most popular accident causation model and is widely used throughout various industries. A debate exists in the research literature over whether the SCM remains a viable tool for accident analysis. Critics of the model suggest that it provides a sequential, oversimplified view of accidents. Conversely, proponents suggest that it embodies the concepts of systems theory, as per the contemporary systemic analysis techniques. The aim of this paper was to consider whether the SCM can provide a systems thinking approach and remain a viable option for accident analysis. To achieve this, the train derailment at Grayrigg was analysed with an SCM-based model (the ATSB accident investigation model) and two systemic accident analysis methods (AcciMap and STAMP). The analysis outputs and usage of the techniques were compared. The findings of the study showed that each model applied the systems thinking approach. However, the ATSB model and AcciMap graphically presented their findings in a more succinct manner, whereas STAMP more clearly embodied the concepts of systems theory. The study suggests that, whilst the selection of an analysis method is subject to trade-offs that practitioners and researchers must make, the SCM remains a viable model for accident analysis

A Ten-Year Study of Individual Outcomes From a Fraternity Central Office Leadership Program

Fraternities promote leadership development as a benefit of membership. Researchers examined fraternal commitment and engagement of participants attending a leadership program offered by a fraternity central office. This study was designed as an outcomes assessment and included 2,065 cases, the total number of fraternity men attending in the ten-year span from 1999-2008. The following data were examined: attendance, undergraduate leadership, alumni/volunteer involvement, and donor rosters, as well as post-program survey evaluations. Descriptive statistics and significance tests revealed that (a) 63% of participants took a formal undergraduate leadership role, (b) 8% of participants took a volunteer advisory role, (c) 8% became donors, and (d) some years were more developmental for participants than others

Accident analysis models and methods: guidance for safety professionals

Accident analysis models and methods provide safety professionals with a means of understanding why accidents occur. Choosing an analysis technique is, however, not a simple process. A wide range of methods are available; each offering various theoretical and practical benefits and drawbacks. Furthermore, individuals engaged in accident investigation are subjected to various factors, e.g. budgetary and time constraints, which can influence their selection and usage of an analysis tool. This report is based on an extensive review of the accident analysis literature and an interview study conducted with 42 safety experts and has two aims. Firstly, it provides an overview of the available analysis techniques and the factors influencing an individual’s choice and usage of these methods. The intention is to provide the reader with information that may enable them to make a more informed selection of analysis tool. The second aim is to present an analysis model currently used in industry. The intention is to provide the reader with a validated method that can be readily employed, if undertaking a detailed assessment of the available techniques is not practicable

Systemic accident analysis: examining the gap between research and practice

The systems approach is arguably the dominant concept within accident analysis research. Viewing accidents as a result of uncontrolled system interactions, it forms the theoretical basis of various systemic accident analysis (SAA) models and methods. Despite the proposed benefits of SAA, such as an improved description of accident causation, evidence within the scientific literature suggests that these techniques are not being used in practice and that a research–practice gap exists. The aim of this study was to explore the issues stemming from research and practice which could hinder the awareness, adoption and usage of SAA. To achieve this, semi-structured interviews were conducted with 42 safety experts from ten countries and a variety of industries, including rail, aviation and maritime. This study suggests that the research–practice gap should be closed and efforts to bridge the gap should focus on ensuring that systemic methods meet the needs of practitioners and improving the communication of SAA research

NovelTM Datasets for English-Language Fiction, 1700-2009

This report describes a collection of 210,305 volumes of fiction that researchers are encouraged to borrow for their own work. Alternately, readers can simply browse the report as a description of English-language fiction in HathiTrust Digital Library. For instance, how does the proportion of fiction written by British authors or by women change across time? We also divide nineteenth- and twentieth-century fiction into seven subsets with different emphases (for instance, one where men and women are represented equally, and one composed of only the most prominent and widely-held books). Comparing the pictures produced by these different samples allows us to assess the fragility of recent quantitative arguments about literary history. Preprint version of an article to appear in the Journal of Cultural Analytics

Teenage trespass on the railways – a systems approach

Rail trespass and risk-taking behaviours are particularly high among 16–25 year olds. The aim of the research described in this paper is to understand how the communication of safety information to these groups can be improved. The study involves focus groups with 117 young people and 43 interviews with stakeholders drawn from the rail industry alongside professionals involved in working with young people. Participants in the focus groups are shown a set of four safety videos which describe the dangers of trespass. The findings demonstrate a number of misconceptions about the dangers and legality of trespass among young people (e.g. lack of awareness of electrocution dangers). Material which includes emotional, ‘real-life’ information in the form of safety narratives is judged to be the most effective in communicating trespass risks. The study also underlines the importance of combining and integrating technical, educational and community-based efforts to reduce trespass

Should there be a future for Tablet PCs in schools?

Tablet PCs are a relatively new format of computer, which seem to offer features which may be beneficial to schools. The uptake of Tablet PCs by schools has been somewhat limited, not least due to their greater cost than laptops of a 'similar' specification. This paper explores the key question of the extent to which schools should be investing in Tablet PCs, if at all, in preference to other formats of fully functional PCs, drawing on evidence from a Becta funded evaluation of the use of Tablet PCs in schools in England conducted in 2004-2005. The Computer Practice Framework was used to develop a set of questions which helped structure a meta-analysis of the data from 12 case studies that formed part of this evaluation. The methodology used and some limitations of the evaluation are outlined, and the key findings are described. The paper concludes that Tablet PCs do appear to offer significant potential to schools, though this potential was not being fully realised in most of the case study schools. A number of specific circumstances in which Tablet PCs do appear to be the most cost effective option are also identified

Remixing Rasmussen: the evolution of Accimaps within systemic accident analysis

Throughout Jens Rasmussen’s career there has been a continued emphasis on the development of methods, techniques and tools for accident analysis and investigation. In this paper we focus on the evolution and development of one specific example, namely Accimaps and their use for accident analysis. We describe the origins of Accimaps followed by a review of 26 studies which have applied and adapted Accimaps over the period 200-2015 to a range of domains and types of accident. Aside from demonstrating the versatility and popularity of the method, part of the motivation for the review of the use of Accimaps is to address the question of what constitutes a sound, usable, valid and reliable approach to systemic accident analysis. The findings from the review demonstrate continuity with the work carried out by Rasmussen, as well as significant variation (e.g., changes to the Accimap, used of additional theoretical and practice-oriented perspectives on safety). We conclude the paper with some speculations regarding future extension and adaptation of the Accimap approach including the possibility of using hybrid models for accident analysis