Emergency Egress for People with Mobility Impairments in Australia

Most people will have a disability, temporary or permanent, at some point in their life; Australian building regulations do not provide equitable means of egress for them. The goal of this project was to investigate how emergency egress codes for people with mobility impairments can be implemented in building regulations. Through interviews and intensive research it was determined that provisions such as areas of refuge and lifts should be included in the Building Code of Australia as a means to mitigate the risk of death

Overlapping and Robust Edge-Colored Clustering in Hypergraphs

A recent trend in data mining has explored (hyper)graph clustering algorithms for data with categorical relationship types. Such algorithms have applications in the analysis of social, co-authorship, and protein interaction networks, to name a few. Many such applications naturally have some overlap between clusters, a nuance which is missing from current combinatorial models. Additionally, existing models lack a mechanism for handling noise in datasets. We address these concerns by generalizing Edge-Colored Clustering, a recent framework for categorical clustering of hypergraphs. Our generalizations allow for a budgeted number of either (a) overlapping cluster assignments or (b) node deletions. For each new model we present a greedy algorithm which approximately minimizes an edge mistake objective, as well as bicriteria approximations where the second approximation factor is on the budget. Additionally, we address the parameterized complexity of each problem, providing FPT algorithms and hardness results

Structural Rounding: Approximation Algorithms for Graphs Near an Algorithmically Tractable Class

We develop a framework for generalizing approximation algorithms from the structural graph algorithm literature so that they apply to graphs somewhat close to that class (a scenario we expect is common when working with real-world networks) while still guaranteeing approximation ratios. The idea is to edit a given graph via vertex- or edge-deletions to put the graph into an algorithmically tractable class, apply known approximation algorithms for that class, and then lift the solution to apply to the original graph. We give a general characterization of when an optimization problem is amenable to this approach, and show that it includes many well-studied graph problems, such as Independent Set, Vertex Cover, Feedback Vertex Set, Minimum Maximal Matching, Chromatic Number, (l-)Dominating Set, Edge (l-)Dominating Set, and Connected Dominating Set. To enable this framework, we develop new editing algorithms that find the approximately-fewest edits required to bring a given graph into one of a few important graph classes (in some cases these are bicriteria algorithms which simultaneously approximate both the number of editing operations and the target parameter of the family). For bounded degeneracy, we obtain an O(r log{n})-approximation and a bicriteria (4,4)-approximation which also extends to a smoother bicriteria trade-off. For bounded treewidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w}))-approximation, and for bounded pathwidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w} * log n))-approximation. For treedepth 2 (related to bounded expansion), we obtain a 4-approximation. We also prove complementary hardness-of-approximation results assuming P != NP: in particular, these problems are all log-factor inapproximable, except the last which is not approximable below some constant factor 2 (assuming UGC)

Exploring the interactions underlying flow states: A connecting analysis of flow occurrence in European Tour golfers

Objectives: Research to date has identified a range of factors suggested to facilitate flow states in sport. However, less attention has focused on how exactly those facilitating factors influence the occurrence of flow. Therefore, this study aimed to explore the specific ways in which such facilitators influenced flow occurrence in European Tour golfers. Design: Qualitative design. Method: Ten full-time golfers from the European Tour (M age=37; SD=13.08) participated in semi-structured interviews investigating the occurrence of their flow states. Data were interpreted using an iterative process of thematic and connecting analyses. Results: Ten facilitators of flow were identified, of which commitment and the caddie have not been reported previously. Twenty four connecting links were identified in the data, through which the caddie, effective preparation, and high-quality performance appeared to be most influential for flow occurrence. Confidence and concentration also emerged as key constructs underlying the flow experience in this setting. Conclusion: A central contribution of this study is the identification of ways in which facilitating factors could influence flow occurrence in elite golf. This process adds detail to understanding of flow occurrence, and moves beyond simply identifying factors which are associated with the experience. As such, connecting analysis is proposed as an additional strategy for qualitatively investigating flow occurrence in sport. Results are discussed in relation to previous literature, and recommendations are identified for researchers, athletes, coaches and practitioners

Gerrymandering Trees: Parameterized Hardness

In a representative democracy, elections involve partitioning geographical space into districts which each elect a single representative. Legislation is then determined by votes from these representatives, and thus political parties are incentivized to win as many districts as possible (ideally a plurality). Gerrymandering is the process by which these districts' boundaries are manipulated to give favor to a certain candidate or party. Cohen-Zemach et al. (AAMAS 2018) proposed Gerrymandering as a formalization of this problem on graphs (as opposed to Euclidean space) where districts partition vertices into connected subgraphs. More recently, Gupta et al. (SAGT 2021) studied its parameterized complexity and gave an FPT algorithm for paths with respect to the number of districts $k$. We prove that Gerrymandering is W[2]-hard on trees (even when the depth is two) with respect to $k$, answering an open question of Gupta et al. Moreover, we prove that Gerrymandering remains W[2]-hard in trees with $\ell$ leaves with respect to the combined parameter $k+\ell$. To complement this result, we provide an algorithm to solve Gerrymandering that is FPT in $k$ when $\ell$ is a fixed constant

Climate mitigation through soil amendments: quantification, evidence, and uncertainty

Soil amendments are a broad class of materials that enhance physical, chemical or biological characteristics in croplands, pastures, or rangelands. While organic soil amendments such as manure, mulch and seaweed have well established agronomic benefits, there has been renewed private and governmental interest in quantifying and incentivizing their role in mitigating climate change. Likewise, biostimulants and biopesticides, which are intended to target specific plant or microbial processes, are emerging with claims of improved soil health, crop yields, soil organic carbon sequestration, and greenhouse gas emission reductions. We conducted a literature review to address the climate mitigation potential of organic soil amendments, including biostimulants and biopesticides. In doing so, we identify three elements of climate mitigation through the use of soil amendments: soil organic carbon sequestration, soil greenhouse gas emission reductions, and life cycle emission reductions. We review common soil amendment classes in detail, addressing the empirical evidence (or lack thereof) in which they meet these three elements of climate mitigation. We conclude by suggesting priorities for government and private investment

Patient-Centered Outcomes Related to Imaging Testing in US Primary Care

Background: Imaging tests are one of the most sophisticated types of diagnostic tools used in health care, yet there are concerns that imaging is overused. Currently, tests are typically evaluated and implemented based on their accuracy, and there is limited knowledge about the range of patient-centered outcomes (PCOs) that imaging tests may lead to. This study explores patients’ experiences and subsequent outcomes of imaging tests most notable to patients. Methods: Adult patients from four primary care clinics who had an x-ray, CT, MRI, or ultrasound in the 12 months before recruitment participated in a single semistructured interview to recount their imaging experience. Interview transcripts were analyzed thematically. Results: Four themes related to PCOs were identified from 45 interviews. Participants’ mean age was 53 years (25-83 years), 30 had undergone a diagnostic imaging test, and 15 underwent imaging for screening or monitoring. Themes included knowledge gained from the imaging test, its contribution to their overall health care journey, physical experiences during the test procedure, and impacts of the testing process on emotions. Conclusions: Patients identified various imaging test outcomes that were important to them. Measurement and reporting these outcomes should be considered more often in diagnostic research. Tools for providers and patients to discuss and utilize these outcomes may help promote shared decision making around the use and impact of imaging tests