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Improving the Reliability of Parallel and Series–Parallel Systems by Reverse Engineering of Algebraic Inequalities
Get PDFThis paper presents a novel, domain-independent method for enhancing system reliability based on reverse engineering of algebraic inequalities. Although system reliability has been extensively studied, existing approaches have not addressed the challenge of improving reliability without knowing the reliability of individual components. This work fills this gap by demonstrating that the reliability of both parallel and series–parallel systems can be improved without any information about component reliability values. Specifically, this study establishes that in parallel systems, a symmetric arrangement of interchangeable components of the same type across parallel branches consistently yields higher system reliability than an asymmetric arrangement—regardless of the individual component reliabilities. This finding is derived through the reverse engineering of a new general algebraic inequality, proposed and proved for the first time. Furthermore, applying the same approach to series–parallel systems reveals that asymmetric arrangements of interchangeable redundancies offer superior system reliability compared with symmetric configurations
Justice at the core: Rethinking the 15-min city for just urban futures
Get PDFThe 15-min city concept, which advocates for urban neighbourhoods where essential services are accessible within a 15-min walk or cycle, has gained substantial attention as a model for promoting sustainable and equitable urban environments. However, while the 15-min city promises a just and equitable urban environment, concerns have emerged regarding its potential to produce unjust outcomes and socio-spatial inequalities, highlighting the need for critical scrutiny from a social justice perspective. Despite its significance, few studies have explored the contribution of the 15-min city to social justice. This study addresses this gap by critically examining how, and to what extent, social justice values are represented in the 15-min city academic literature. A structured content analysis of existing literature was undertaken, guided by four key questions: (1) How is social justice represented in the definitions and conceptualisations of the 15-min city? (2) How and to what extent do the principles of the 15-min city advocate social justice? (3) What potential concerns and justice-related challenges are discussed in the literature? and (4) What recommendations are proposed to promote social justice in the literature? Our findings suggest that while social justice is acknowledged within the theoretical framework of the 15-min city and demonstrates promising potential for fostering equitable urban environments, a more deliberate integration of social justice values as a guiding principle is essential. Accordingly, this study recommends the establishment of robust equity monitoring mechanisms, the institutionalisation of participatory planning processes, and the implementation of inclusivity audits
The effect of ash dieback on soil hydrology and ground flora functional traits
No full textGlobal trade and a changing climate have expanded the range of invasive pathogens, with potentially devastating effects on biodiversity. Invasive pathogens such as Dutch elm disease and chestnut blight have decimated tree populations and damaged forest ecosystems. Widespread tree loss affects local environmental conditions including canopy cover and soil hydrology, changing ground flora communities. Plant functional traits can be used to understand how communities respond to these environmental changes and how they shape ecosystem processes. Understanding the effects of ash dieback on local environmental conditions and ground flora communities is of great importance to future conservation and restoration efforts. Here I use an experimental set-up to investigate how increasing levels of ash dieback affect soil moisture levels and ground flora community trait values. I find that soil moisture levels increase with advancing stages of ash dieback and that between-habitat differences vary with the seasons. I find some variation in ground flora traits between woodland at different stages of ash dieback, not fully explained by the environmental variables measured in this study. Contrary to my predictions and the findings of previous studies, ground flora traits were not highly correlated with soil moisture. Canopy cover emerges as the most important driver of leaf traits, though soil moisture has some effect. Of the ground flora traits measured seed mass shows the largest response to differences between habitats at different stages of ash dieback, with soil moisture also showing some influence. Reduction of seed mass with advancing ash dieback could reflect abiotic filtering combined with a filtering effect from competitive interactions as rapid colonisers proliferate. I show the implications my results have for management of affected woodlands and identify potential areas for future research
The eudaimonic well-being of entrepreneurs : a gendered perspective
No full textEntrepreneurial well-being has received considerable interest during the past few years. However, literature is limited on the eudaimonic well-being of women entrepreneurs, even though it is recognized that gendered social roles and expectations impose time and resource limitations that can affect women’s ability to flourish and achieve well-being. The study builds a theoretical model explaining how several factors embedded in the family and community (personal life interference with work, personal-life enhancement of work, and sense of community) affect the eudaimonic well-being of self-employed women and men. Further, we test the role of young children and flexible working arrangements (work from home). Using a sample of 656 self-employed individuals from the Canadian Index of Well-Being survey, our results demonstrate significant differences in how personal life interference with work and the presence of young children constrain the ability of self-employed women (vis-a-vis their male counterparts) to fulfill their eudaimonic well-being