Orienting edges to fight fire in graphs

International audienceWe investigate a new oriented variant of the Firefighter Problem. In the traditional Firefighter Problem, a fire breaks out at a given vertex of a graph, and at each time interval spreads to neighbouring vertices that have not been protected, while a constant number of vertices are protected at each time interval. In the version of the problem considered here, the firefighters are able to orient the edges of the graph before the fire breaks out, but the fire could start at any vertex. We consider this problem when played on a graph in one of several graph classes, and give upper and lower bounds on the number of vertices that can be saved. In particular, when one firefighter is available at each time interval, and the given graph is a complete graph, or a complete bipartite graph, we present firefighting strategies that are provably optimal. We also provide lower bounds on the number of vertices that can be saved as a function of the chromatic number, of the maximum degree, and of the treewidth of a graph. For a subcubic graph, we show that the firefighters can save all but two vertices, and this is best possible

Evolving scout agents for military simulations

textSimulations play an increasingly significant role in training and preparing the military, particularly in environments with constrained budgets. Unfortunately, in most cases a small number of people must control a large number of simulated vehicles and soldiers. This often leads to micromanagement of computer-controlled forces in order to get them to exhibit the human-like characteristics of an enemy force. This thesis uses Neuroevolution of Augmenting Topologies (NEAT) to train neural networks to perform the role of scouts which analyze the terrain and decide where to place themselves to best observe the enemy forces. The main attribute that the scout agents consider is a vapor flow rate from the enemy starting location to their intended objective, which according to previous studies indicates likely chokepoints along the enemy route. This thesis experiments with different configurations of sensors and fitness functions in order to maximize how much of the enemy team is spotted over the course of the scenario. The results show that these agents perform better than randomly placed scouts and better than scouts deployed using heuristics in many situations, although not consistently so. Evolutionary optimization of scout agents using vapor flow is thus a promising approach for developing autonomous scout agents in military simulations.Computer Science

Actor-Network VS Network Analysis VS Digital Networks: Are We Talking About the Same Networks?

International audienceTo appear as a chapter of the Digital STS Handbook (digitalsts.net) This paper discusses the differences and affinities among three types of networks (namely Actor-Networks, Social Networks and Digital Networks) that are playing an increasingly important role in digital STS. In the last few decades, the notion of networks has slowly but steadily struck root across broad strands of STS research. It started with the advent of actor-network theory, which provided a convenient instrument to describe the construction work of socio-technical phenomena. Then came network analysis, and scholars who imported into STS the techniques of investigation and visualization developed in the tradition of social network analysis and scientometrics. Finally, with the increasing 'computerization' of STS, scholars turned their attention to digital networks as a way of tracing collective life. Many researchers have more or less explicitly tried to link these three movements in one coherent set of digital methods, betting on the idea that actor-network theory can be operationalized through network analysis thanks to the data provided by digital networks. Yet, to be honest, the affinity between these three objects is sketchy at best. Besides the homonym 'network', there is little to is little to show for it. Are we sure that we are talking about the same thing? "Odi et amo. quare id faciam, fortasse requiris? nescio, sed fieri sentio et excrucior." Catullus 85 or Carmina LXXXV Professor — you should not confuse the network that is drawn by the description and the network that is used to make the description. Student — …? Professor — But yes! Surely you'd agree that drawing with a pencil is not the same thing as drawing the shape of a pencil. It's the same with this ambiguous word, network. With Actor-Network you may describe something that doesn't at all look like a network — an individual state of mind, a piece of machinery, a fictional character; conversely, you may describe a network — subways, sewages, telephones — which is not all drawn in an 'Actor-Networky' way. You are simply confusing the object with the method. ANT is a method, and mostly a negative one at that; it says nothing about the shape of what is being described with it. Student — This is confusing! But my company executives, are they not forming a nice, revealing, significant network? Professor — Maybe yes, I mean, surely, yes— but so what? Student — Then, I can study them with Actor-Network-Theory

Dimentia: Footnotes of Time

Time from the physicist\u27s perspective is not inclusive of our lived experience of time; time from the philosopher\u27s perspective is not mathematically engaged, in fact Henri Bergson asserted explicitly that time could not be mathematically engaged whatsoever. What follows is a mathematical engagement of time that is inclusive of our lived experiences, requiring the tools of storytelling

From Reclamation to Conservation: A History of Settler Place-Making in Burns Bog, British Columbia

Wetlands are, in the Canadian settler imaginary, ambiguous spaces that are neither strictly landmasses nor only bodies of water. This paper explores how Canadian settler-colonialism has incorporated wetlands into systems of land ownership and control by tracing the history a specific wetland, a peat bog known as Burns Bog since the 1930s in the area settlers call Delta, British Columbia. Given its presence as one of the largest wetlands in the region, settlers failed to drain the bog in its entirety. As a result, the bog persisted throughout the history of settlers’ presence on the west coast and has been subjected to waves of settler approaches, making it an ideal case study to consider how ongoing settler-colonialism has shaped, and continues to shape, wetlands. Previous historical works on wetlands in Canada and the United States have documented how early settlers, through to roughly the mid-twentieth century, worked to “reclaim” wetlands and transform them into arable land. However, these accounts have often neglected to continue their analysis of settler-colonialism beyond this period and have, as a result, treated settlers’ more contemporary views of wetlands -- as ecologically valuable ecosystems that need to be conserved or restored -- as a break in colonial dynamics. This research intervenes in this existing body of work by treating shifting practices towards wetlands as successive stages in efforts to incorporate wetlands into settler-colonial logics. I argue that these different practices need to be interrogated for how they both rely on similar logics, frameworks, and approaches to the nonhuman, and for how they further the settler-colonial project of suppressing Indigenous voices, histories, and relations to land. The paper draws upon Indigenous studies, queer ecology, and posthumanism to develop a more theoretically robust framework through which to approach the history of Burns Bog. I use a collection of archival and secondary materials—particularly early ethnographies of the region— to trace Indigenous and settler relations to the bog. In chapter 1, I present a framework that pays particular attention to settler practices and conceptions of land, biopolitical capitalist subsumption of the nonhuman, and methods of thinking with and through water. In chapter 2, I trace the bog’s history from its formation through to the 1920s, including Indigenous peoples’ relations to the bog and early settler efforts to reclaim the bog. Chapter 3 explores the rise of different settler practices in the bog from the 1930s to the 1980s, especially peat extraction, cranberry farming, and the use of the bog as a landfill. Chapter 4 presents the rise in scientific and conservation approaches to Burns Bog, highlighting how they provide a means for making the bog more legible and enabling more extensive settler direction of nonhuman beings within the bog as well as the resurgence of Indigenous claims to the bog. I argue that by viewing wetlands as ongoing and overlapping collections of material and narrative practices, we can see how contemporary conservation politics often function as an extension of settler domination of land

Temperament & Character account for brain functional connectivity at rest: A diathesis-stress model of functional dysregulation in psychosis

The online version contains supplementary material available at https://doi.org/10.1038/s41380-023-02039-6The human brain’s resting-state functional connectivity (rsFC) provides stable trait-like measures of differences in the perceptual, cognitive, emotional, and social functioning of individuals. The rsFC of the prefrontal cortex is hypothesized to mediate a person’s rational self-government, as is also measured by personality, so we tested whether its connectivity networks account for vulnerability to psychosis and related personality configurations. Young adults were recruited as outpatients or controls from the same communities around psychiatric clinics. Healthy controls (n = 30) and clinically stable outpatients with bipolar disorder (n = 35) or schizophrenia (n = 27) were diagnosed by structured interviews, and then were assessed with standardized protocols of the Human Connectome Project. Data-driven clustering identified five groups of patients with distinct patterns of rsFC regardless of diagnosis. These groups were distinguished by rsFC networks that regulate specific biopsychosocial aspects of psychosis: sensory hypersensitivity, negative emotional balance, impaired attentional control, avolition, and social mistrust. The rsFc group differences were validated by independent measures of white matter microstructure, personality, and clinical features not used to identify the subjects. We confirmed that each connectivity group was organized by differential collaborative interactions among six prefrontal and eight other automatically-coactivated networks. The temperament and character traits of the members of these groups strongly accounted for the differences in rsFC between groups, indicating that configurations of rsFC are internal representations of personality organization. These representations involve weakly self-regulated emotional drives of fear, irrational desire, and mistrust, which predispose to psychopathology. However, stable outpatients with different diagnoses (bipolar or schizophrenic psychoses) were highly similar in rsFC and personality. This supports a diathesis-stress model in which different complex adaptive systems regulate predisposition (which is similar in stable outpatients despite diagnosis) and stress-induced clinical dysfunction (which differs by diagnosis).EU FEDER grants through the Spanish Ministry of Science and Technology PID2021-125017OB-I00, RTI2018-098983-B-I00, D43 TW011793-06A1, PID2021-125017OB-I00, RTI2018-098983-B-I00, D43 TW011793-06A1United States Department of Health & Human Services National Institutes of Health (NIH) - USA R01-MH124060Psychosis-Risk Outcomes Network U01 MH12463

Temperament & Character account for brain functional connectivity at rest: A diathesis-stress model of functional dysregulation in psychosis

The human brain’s resting-state functional connectivity (rsFC) provides stable trait-like measures of differences in the perceptual, cognitive, emotional, and social functioning of individuals. The rsFC of the prefrontal cortex is hypothesized to mediate a person’s rational self-government, as is also measured by personality, so we tested whether its connectivity networks account for vulnerability to psychosis and related personality configurations. Young adults were recruited as outpatients or controls from the same communities around psychiatric clinics. Healthy controls (n = 30) and clinically stable outpatients with bipolar disorder (n = 35) or schizophrenia (n = 27) were diagnosed by structured interviews, and then were assessed with standardized protocols of the Human Connectome Project. Data-driven clustering identified five groups of patients with distinct patterns of rsFC regardless of diagnosis. These groups were distinguished by rsFC networks that regulate specific biopsychosocial aspects of psychosis: sensory hypersensitivity, negative emotional balance, impaired attentional control, avolition, and social mistrust. The rsFc group differences were validated by independent measures of white matter microstructure, personality, and clinical features not used to identify the subjects. We confirmed that each connectivity group was organized by differential collaborative interactions among six prefrontal and eight other automatically-coactivated networks. The temperament and character traits of the members of these groups strongly accounted for the differences in rsFC between groups, indicating that configurations of rsFC are internal representations of personality organization. These representations involve weakly self-regulated emotional drives of fear, irrational desire, and mistrust, which predispose to psychopathology. However, stable outpatients with different diagnoses (bipolar or schizophrenic psychoses) were highly similar in rsFC and personality. This supports a diathesis-stress model in which different complex adaptive systems regulate predisposition (which is similar in stable outpatients despite diagnosis) and stress-induced clinical dysfunction (which differs by diagnosis)

Proceedings of the First Workshop on Computing News Storylines (CNewsStory 2015)

This volume contains the proceedings of the 1st Workshop on Computing News Storylines (CNewsStory 2015) held in conjunction with the 53rd Annual Meeting of the Association for Computational Linguistics and the 7th International Joint Conference on Natural Language Processing (ACL-IJCNLP 2015) at the China National Convention Center in Beijing, on July 31st 2015. Narratives are at the heart of information sharing. Ever since people began to share their experiences, they have connected them to form narratives. The study od storytelling and the field of literary theory called narratology have developed complex frameworks and models related to various aspects of narrative such as plots structures, narrative embeddings, characters’ perspectives, reader response, point of view, narrative voice, narrative goals, and many others. These notions from narratology have been applied mainly in Artificial Intelligence and to model formal semantic approaches to narratives (e.g. Plot Units developed by Lehnert (1981)). In recent years, computational narratology has qualified as an autonomous field of study and research. Narrative has been the focus of a number of workshops and conferences (AAAI Symposia, Interactive Storytelling Conference (ICIDS), Computational Models of Narrative). Furthermore, reference annotation schemes for narratives have been proposed (NarrativeML by Mani (2013)). The workshop aimed at bringing together researchers from different communities working on representing and extracting narrative structures in news, a text genre which is highly used in NLP but which has received little attention with respect to narrative structure, representation and analysis. Currently, advances in NLP technology have made it feasible to look beyond scenario-driven, atomic extraction of events from single documents and work towards extracting story structures from multiple documents, while these documents are published over time as news streams. Policy makers, NGOs, information specialists (such as journalists and librarians) and others are increasingly in need of tools that support them in finding salient stories in large amounts of information to more effectively implement policies, monitor actions of “big players” in the society and check facts. Their tasks often revolve around reconstructing cases either with respect to specific entities (e.g. person or organizations) or events (e.g. hurricane Katrina). Storylines represent explanatory schemas that enable us to make better selections of relevant information but also projections to the future. They form a valuable potential for exploiting news data in an innovative way.JRC.G.2-Global security and crisis managemen

Appalachia Winter/Spring 2014: Complete Issue

Winter/Spring 2014 - Volume LXV, Number 1 - issue #237. At Large: Four Stories of Escape to Wilder Land