1,721,090 research outputs found
Autonomous Traffic Management:Integrating Vissim Traffic Model with a Swarm of Drones
No full textIn this research, we propose a system for monitoring and efficiently managing traffic congestion at the intersection of Park Avenue and E 72nd Street, New York, USA. This methodology is applied to a realistic traffic scenario where all intersections are controlled by fixed traffic signals. The method is based on a data-driven approach deploying a swarm of drones to measure the number of vehicles on roads. The collected information by the drones is sent to traffic lights and simultaneous perturbation stochastic approximation (SPSA) method is used to minimize traffic congestion by adapting the green traffic light durations. More precisely, we simulate the scenario thanks to the Vissim traffic software and Python. The simulation results highlight the effects of traffic light optimization to reduce traffic jams in contrast to the baseline case, where the duration of green lights is fixed.</p
Costs of Information Gathering Strategies and Their Impact on Animal Dispersal
No full textAnimal dispersal is among the most impacted behaviours from habitat loss and fragmentation. Animals disperse in search of better conditions to ultimately increase their fitness. However, the dispersal process induces costs that can be translated as a loss in fecundity or as an increase in predation risks. In this study, we use an evolutionary multi-agent model to quantify how costs related to information acquisition shape information gathering strategies used in animal dispersal. We separate costs of private information, i.e., related to the direct acquisition of information sensed in the physical environment, from costs related to social information, i.e., derived from the observation of conspecifics behaviour. We find that a low mortality risk associated with dispersal movements selects non-informed dispersal in low-variability environments. However, high-variability environments select an information gathering strategy based on the exploration of multiple patches of habitat. A higher mortality risk causes drastic drops in population abundance and agents gather information from only one patch to limit their movements. Overall, private information is predominantly used in high-variability environments while social and private information are used equally in low-variability environments.</p
Explaining social learning of food preferences without aversions: an evolutionary simulation model of Norway rats
No full textNorway rats (Rattus norvegicus) transmit preferences for novel foods socially by smelling each other's breath. However, rats fail to learn aversions, acquiring a preference even if the rat whose breath they smell has been poisoned. Rats can distinguish between sick and healthy conspecifics and social learning of both preferences and aversions is present in other species - hence it is unclear why rats cannot learn aversions socially. We constructed an evolutionary simulation in which a population of rats foraged from a central location, exploiting food sites that could contain edible or toxic foodstuffs. We examined the relationship between toxin lethality and selection for individual versus social learning and discrimination between sick and healthy conspecifics in order to allow learning of both preferences and aversions. At low lethality levels individual learning was selected for and at intermediate levels we found social learning of both preferences and aversions. Finally, given high lethality levels the simulated rats would employ social learning but failed to learn aversions, matching the behaviour of real rats. We argue that Norway rats do not learn aversions socially because their environment may contain only highly lethal toxins which make interaction with a sick conspecific an extremely rare event
Implementation of the response to synchronization in e-puck2 robots
Full text linkThe response to synchronization is a phenomenon observed in several firefly species, where male ensembles synchronize their rhythmic flashes by triggering a response from females which ends the courtship process. In this work, we present a robotic implementation of this phenomenon by using a team of static e-puck2 robots that integrate oscillatory dynamics to mimic the flashing rhythm of the fireflies. To this end, robots communicate with each other via infrared (IR) and follow a distributed control law. They are divided into two groups: one representing the male population with bursting dynamics and the other representing females with non-bursting behavior. Our experimental results demonstrate that response to synchronization is robust with respect to the presence of realistic features such as obstacles and information loss. These factors play a significant role in refining the original model and enhancing its applicability in real-world scenarios
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Abstraction as a Mechanism to Cross the Reality Gap in Evolutionary Robotics
No full textOne of the major challenges of Evolutionary Robotics is to transfer robot controllers evolved in simulation to robots in the real world. In this article, we investigate abstraction on the sensory inputs and motor actions as a potential solution to this problem. Abstraction means that the robot uses preprocessed sensory inputs and closed loop low-level controllers that execute higher level motor commands. We apply abstraction to the task of forming an asymmetric triangle with a homogeneous swarm of MAVs. The results show that the evolved behavior is effective both in simulation and reality, suggesting that abstraction can be a useful tool in making evolved behavior robust to the reality gap. Furthermore, we study the evolved solution, showing that it exploits the environment (in this case the identical behavior of the other robots) and creates behavioral attractors resulting in the creation of the required formation. Hence, the analysis suggests that by using abstraction, sensory-motor coordination is not necessarily lost but rather shifted to a higher level of abstraction.Control & Simulatio
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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