Exploring Millions of 6-State FSSP Solutions: the Formal Notion of Local CA Simulation

In this paper, we come back on the notion of local simulation allowing to transform a cellular automaton into a closely related one with different local encoding of information. This notion is used to explore solutions of the Firing Squad Synchronization Problem that are minimal both in time (2n -- 2 for n cells) and, up to current knowledge, also in states (6 states). While only one such solution was proposed by Mazoyer since 1987, 718 new solutions have been generated by Clergue, Verel and Formenti in 2018 with a cluster of machines. We show here that, starting from existing solutions, it is possible to generate millions of such solutions using local simulations using a single common personal computer

HPO: We won’t get fooled again

Hyperparameter optimization (HPO) is a well-studied research field. However, the effects and interactions of the components in an HPO pipeline are not yet well investigated. Then, we ask ourselves: Can the landscape of HPO be biased by the pipeline used to evaluate individual configurations? To address this question, we proposed to analyze the effect of the HPO pipeline on HPO problems using fitness landscape analysis. Particularly, we studied the DS-2019 HPO benchmark data set, looking for patterns that could indicate evaluation pipeline malfunction, and relate them to HPO performance. Our main findings are: (i) In most instances, large groups of diverse hyperparameters (i.e., multiple configurations) yield the same \emph{ill} performance, most likely associated with majority class prediction models; (ii) in these cases, a worsened correlation between the observed fitness and average fitness in the neighborhood is observed, potentially making harder the deployment of local-search-based HPO strategies. Finally, we concluded that the HPO pipeline definition might negatively affect the HPO landscape

Remarks on the cellular automaton global synchronisation problem – deterministic vs. stochastic models

International audienceIn the global synchronisation problem, one is asked to find a cellular automaton which has the property that every initial condition evolves into a homogeneous blinking state. We study this simple inverse problem for the case of one-dimensional systems with periodic boundary conditions. Two paradoxical observations are made: (a) despite the apparent simplicity of finding rules with good statistical results, there exist no perfect deterministic solutions to this problem, (b) if we allow the use of randomness in the local rule, constructing ``perfect" stochastic solutions is easy. For the stochastic case, we give some rules for which the mean time of synchronisation varies quadratically with the number of cells and ask if this result can be improved.To explore more deeply the deterministic rules, we code our problem as a SAT problem and USE SAT solvers to find rules that synchronise a large set of initial conditions (in appendix)

Optimizing combat capabilities by modeling combat as a complex adaptive system

Procuring combat systems in the Department of Defense is a balancing act where many variables, only some under control of the department, shift simultaneously. Technology changes non-linearly, providing new opportunities and new challenges to the existing and potential force. Money available changes year over year to fit into the overall US Government budget. Numbers of employees change through political demands rather than by cost-effectiveness considerations. The intent is to provide the best mix of equipment to field the best force against an expected enemy while maintaining adequate capability against the unexpected. Confounding this desire is the inability of current simulations to dynamically model changing capabilities and the very large universe of potential combinations of equipment and tactics.;The problem can be characterized as a stochastic, mixed-integer, non-linear optimization problem. This dissertation proposes to combine an agent-based model developed to test solutions that constitute both equipment capabilities and tactics with a co-evolutionary genetic algorithm to search this hyper-dimensional solution space. In the process, the dissertation develops the theoretical underpinning for using agent-based simulations to model combat. It also provides the theoretical basis for improvement of search effectiveness by co-evolving multiple systems simultaneously, which increases exploitation of good schemata and widens exploration of new schemata. Further, it demonstrates the effectiveness of using agent-based models and co-evolution in this application confirming the theoretical results.;An open research issue is the value of increased information in a system. This dissertation uses the combination of an agent-based model with a co-evolutionary genetic algorithm to explore the value added by increasing information in a system. The result was an increased number of fit solutions, rather than an increase in the fitness of the best solutions. Formerly unfit solutions were improved by increasing the information available making them competitive with the most fit solutions whereas already fit solutions were not improved

A technique for determining viable military logistics support alternatives

A look at today's US military will see them operating much beyond the scope of protecting and defending the United States. These operations now consist of, but are not limited to humanitarian aid, disaster relief, and conflict resolution. This broad spectrum of operational environments has necessitated a transformation of the individual military services into a hybrid force that can leverage the inherent and emerging capabilities from the strengths of those under the umbrella of the Department of Defense (DOD), this concept has been coined Joint Operations. Supporting Joint Operations requires a new approach to determining a viable military logistics support system. The logistics architecture for these operations has to accommodate scale, time, varied mission objectives, and imperfect information. Compounding the problem is the human in the loop (HITL) decision maker (DM) who is a necessary component for quickly assessing and planning logistics support activities. Past outcomes are not necessarily good indicators of future results, but they can provide a reasonable starting point for planning and prediction of specific needs for future requirements. Adequately forecasting the necessary logistical support structure and commodities needed for any resource intensive environment has progressed well beyond stable demand assumptions to one in which dynamic and nonlinear environments can be captured with some degree of fidelity and accuracy. While these advances are important, a holistic approach that allows exploration of the operational environment or design space does not exist to guide the military logistician in a methodical way to support military forecasting activities. To bridge this capability gap, a method called A Technique for Logistics Architecture Selection (ATLAS) has been developed. This thesis describes and applies the ATLAS method to a notional military scenario that involves the Navy concept of Seabasing and the Marine Corps concept of Distributed Operations applied to a platoon sized element. This work uses modeling and simulation to incorporate expert opinion and knowledge of military operations, dynamic reasoning methods, and certainty analysis to create a decisions support system (DSS) that can be used to provide the DM an enhanced view of the logistics environment and variables that impact specific measures of effectiveness.Ph.D.Committee Chair: Mavris, Dimitri; Committee Member: Fahringer, Philip; Committee Member: Nixon, Janel; Committee Member: Schrage, Daniel; Committee Member: Soban, Danielle; Committee Member: Vachtsevanos, Georg

Gaining Insight into Determinants of Physical Activity using Bayesian Network Learning

Contains fulltext : 228326pre.pdf (preprint version ) (Open Access) Contains fulltext : 228326pub.pdf (publisher's version ) (Open Access)BNAIC/BeneLearn 202

The rhythm that unites: an empirical investigation into synchrony, ritual, and hierarchy

Synchrony, or rhythmic bodily unison activities such as drumming or cadence marching, has attracted growing scholarly interest. Among laboratory subjects, synchrony elicits prosocial responses, including altruism and empathy. In light of such findings, researchers in social psychology and the bio-cultural study of religion have suggested that synchrony played a role in humanity’s evolutionary history by engendering collectivistic commitments and social cohesion. These models propose that synchrony enhances cohesion by making people feel united. However, such models overlook the importance of differentiated social relations, such as hierarchies. This dissertation builds on this insight by drawing on neuroscience, coordination dynamics, social psychology, anthropology, and ritual studies to generate a complex model of synchrony, ritual, and social hierarchy, which is then tested in an experimental study. In the hypothesized model, shared motor unison suppresses the brain’s ability to distinguish cognitively between self-caused and exogenous motor acts, resulting in subjective self-other overlap. During synchrony each participant is dynamically entrained to a group mean rhythm; this “immanent authority” prevents any one participant from unilaterally dictating the rhythm, flattening relative hierarchy. As a ritualized behavior, synchrony therefore paradigmatically evokes shared ideals of equality and unity. However, when lab participants were assigned to either a synchrony or asynchrony manipulation and given a collaborative task requiring complex coordination, synchrony predicted a marginally lower degree of collaboration and significantly lower interpersonal satisfaction. These findings imply that unity and equality can undercut group cohesion if the collective agenda is a shared goal that requires interpersonal coordination. My results emphasize that, despite the inevitable tensions associated with social hierarchy, complementary roles and hierarchy are vital for certain aspects of social cohesion. Ritual and convention institute social boundaries that can be adroitly negotiated, even as egalitarian effervescence such as communitas (in the sense of Victor Turner) facilitates social unity and inspires affective commitments. These findings corroborate theories in ritual studies and sociology that caution both against excessive emphasis on inner emotive states (such as empathy) and against excessively rigid conventions or roles. An organic balance between unity and functional differentiation is vital for genuinely robust, long-term social cohesion.2018-06-21T00:00:00

Programmation et indécidabilités dans les systèmes complexes

N/AUn système complexe est un système constitué d'un ensemble d'entités quiinteragissent localement, engendrant des comportements globaux, émergeant dusystème, qu'on ne sait pas expliquer à partir du comportement local, connu, desentités qui le constituent. Nos travaux ont pour objet de mieux cerner lesliens entre certaines propriétés des systèmes complexes et le calcul. Parcalcul, il faut entendre l'objet d'étude de l'informatique, c'est-à-dire ledéplacement et la combinaison d'informations. À l'aide d'outils issus del'informatique, l'algorithmique et la programmation dans les systèmes complexessont abordées selon trois points de vue. Une première forme de programmation,dite externe, consiste à développer l'algorithmique qui permet de simuler lessystèmes étudiés. Une seconde forme de programmation, dite interne, consiste àdévelopper l'algorithmique propre à ces systèmes, qui permet de construire desreprésentants de ces systèmes qui exhibent des comportements programmés. Enfin,une troisième forme de programmation, de réduction, consiste à plonger despropriétés calculatoires complexes dans les représentants de ces systèmes pourétablir des résultats d'indécidabilité -- indice d'une grande complexitécalculatoire qui participe à l'explication de la complexité émergente. Afin demener à bien cette étude, les systèmes complexes sont modélisés par desautomates cellulaires. Le modèle des automates cellulaires offre une dualitépertinente pour établir des liens entre complexité des propriétés globales etcalcul. En effet, un automate cellulaire peut être décrit à la fois comme unréseau d'automates, offrant un point de vue familier de l'informatique, etcomme un système dynamique discret, une fonction définie sur un espacetopologique, offrant un point de vue familier de l'étude des systèmesdynamiques discrets.Une première partie de nos travaux concerne l'étude de l'objet automatecellulaire proprement dit. L'observation expérimentale des automatescellulaires distingue, dans la littérature, deux formes de dynamiques complexesdominantes. Certains automates cellulaires présentent une dynamique danslaquelle émergent des structures simples, sortes de particules qui évoluentdans un domaine régulier, se rencontrent lors de brèves collisions, avant degénérer d'autres particules. Cette forme de complexité, dans laquelletransparaît une notion de quanta d'information localisée en interaction, estl'objet de nos études. Un premier champ de nos investigations est d'établir uneclassification algébrique, le groupage, qui tend à rendre compte de ce type decomportement. Cette classification met à jour un type d'automate cellulaireparticulier : les automates cellulaires intrinsèquement universels. Un automatecellulaire intrinsèquement universel est capable de simuler le comportement detout automate cellulaire. C'est l'objet de notre second champ d'investigation.Nous caractérisons cette propriété et démontrons son indécidabilité. Enfin, untroisième champ d'investigation concerne l'algorithmique des automatescellulaires à particules et collisions. Étant donné un ensemble de particuleset de collisions d'un tel automate cellulaire, nous étudions l'ensemble desinteractions possibles et proposons des outils pour une meilleure programmationinterne à l'aide de ces collisions.Une seconde partie de nos travaux concerne la programmation par réduction. Afinde démontrer l'indécidabilité de propriétés dynamiques des automatescellulaires, nous étudions d'une part les problèmes de pavage du plan par desjeux de tuiles finis et d'autre part les problèmes de mortalité et depériodicité dans les systèmes dynamiques discrets à fonction partielle. Cetteétude nous amène à considérer des objets qui possèdent la même dualité entredescription combinatoire et topologique que les automates cellulaires. Unenotion d'apériodicité joue un rôle central dans l'indécidabilité des propriétésde ces objets