共查询到20条相似文献,搜索用时 15 毫秒
1.
Self-organized flocking in mobile robot swarms 总被引:1,自引:0,他引:1
In this paper, we study self-organized flocking in a swarm of mobile robots. We present Kobot, a mobile robot platform developed specifically for swarm robotic studies. We describe its infrared-based short range sensing system, capable of measuring the distance from obstacles and detecting kin robots, and a novel sensing system called the virtual heading system (VHS) which uses a digital compass and a wireless communication module for sensing the relative headings of neighboring robots. We propose a behavior based on heading alignment and proximal control that is capable of generating self-organized flocking in a swarm of Kobots. By self-organized flocking we mean that a swarm of mobile robots, initially connected via proximal sensing, is able to wander in an environment by moving as a coherent group in open space and to avoid obstacles as if it were a “super-organism”. We propose a number of metrics to evaluate the quality of flocking. We use a default set of behavioral parameter values that can generate acceptable flocking in robots, and analyze the sensitivity of the flocking behavior against changes in each of the parameters using the metrics that were proposed. We show that the proposed behavior can generate flocking in a small group of physical robots in a closed arena as well as in a swarm of 1000 simulated robots in open space. We vary the three main characteristics of the VHS, namely: (1) the amount and nature of noise in the measurement of heading, (2) the number of VHS neighbors, and (3) the range of wireless communication. Our experiments show that the range of communication is the main factor that determines the maximum number of robots that can flock together and that the behavior is highly robust against the other two VHS characteristics. We conclude by discussing this result in the light of related theoretical studies in statistical physics. 相似文献
2.
Search and rescue, autonomous construction, and many other semi-autonomous multirobot applications can benefit from proximal interactions between an operator and a swarm of robots. Most research on proximal interaction is based on explicit communication techniques such as gesture and speech. This study proposes a new implicit proximal communication technique to approach the problem of robot selection. We use electroencephalography (EEG) signals to select the robot at which the operator is looking. This is achieved using steady-state visually evoked potential (SSVEP), a repeatable neural response to a regularly blinking visual stimulus that varies predictively based on the blinking frequency. In our experiments, each robot was equipped with LEDs blinking at a different frequency, and the operator’s SSVEP neural response was extracted from the EEG signal to detect and select the robot without requiring any conscious action by the user. This study systematically investigates several parameters affecting the SSVEP neural response: blinking frequency of the LED, distance between the robot and the operator, and color of the LED. Based on these parameters, we study two signal processing approaches and critically analyze their performance on 10 subjects controlling a set of physical robots. Our results show that despite numerous artifacts, it is possible to achieve a recognition rate higher than 85 % on some subjects, while the average over the ten subjects was 75 %. 相似文献
3.
Theise ND 《Comptes rendus biologies》2002,325(10):1039-1043
Recent discoveries demonstrating surprising cell plasticity in animals and humans call into question many long held assumptions regarding differentiative potential of adult cells. These assumptions reflect a classical paradigm of cell lineage development projected onto both prenatal development and post-natal maintenance and repair of tissues. The classical paradigm describes unidirectional, hierarchical lineages proceedings step-wise from totipotent or pluripotent stem cells through intermediate, ever more restricted progenitor cells, leading finally to 'terminally differentiated' cells. However, in light of both the recent discoveries and older clinical or experimental findings, we have suggested principles comprising a new paradigm of cell plasticity, summarized here. 相似文献
4.
Gianpiero Francesca Manuele Brambilla Arne Brutschy Vito Trianni Mauro Birattari 《Swarm Intelligence》2014,8(2):89-112
We introduce AutoMoDe: a novel approach to the automatic design of control software for robot swarms. The core idea in AutoMoDe recalls the approach commonly adopted in machine learning for dealing with the bias–variance tradedoff: to obtain suitably general solutions with low variance, an appropriate design bias is injected. AutoMoDe produces robot control software by selecting, instantiating, and combining preexisting parametric modules—the injected bias. The resulting control software is a probabilistic finite state machine in which the topology, the transition rules and the values of the parameters are obtained automatically via an optimization process that maximizes a task-specific objective function. As a proof of concept, we define AutoMoDe-Vanilla, which is a specialization of AutoMoDe for the e-puck robot. We use AutoMoDe-Vanilla to design the robot control software for two different tasks: aggregation and foraging. The results show that the control software produced by AutoMoDe-Vanilla (i) yields good results, (ii) appears to be robust to the so called reality gap, and (iii) is naturally human-readable. 相似文献
5.
Costs of plasticity in foraging characteristics of the clonal plant Ranunculus reptans 总被引:3,自引:0,他引:3
van Kleunen M Fischer M Schmid B 《Evolution; international journal of organic evolution》2000,54(6):1947-1955
In clonal plants, evolution of plastic foraging by increased lengths of leaves and internodes under unfavourable conditions may be constrained by costs and limits of plasticity. We studied costs and limits of plasticity in foraging characteristics in 102 genotypes of the stoloniferous herb Ranunculus reptans. We grew three replicates of each genotype with and three without competition by the naturally co-occuring grass Agrostis stolonifera. We used regression and correlation analyses to investigate potential costs of plasticity in lengths of leaves and stolon internodes, developmental instability costs of these traits, and a developmental range limit of these traits. We used randomization procedures to control for spurious correlations between parameters calculated from the same data. Under competition the number of rosettes, rooted rosettes, and flowers was 58%, 40%, and 61% lower, respectively, than in the absence of competition. Under competition lengths of leaves and stolon internodes were 14% and 6% smaller, respectively, than in the absence of competition. We detected significant costs of plasticity in stolon internode length in the presence of competition when fitness was measured in terms of the number of rosettes and the number of flowers (selection gradients against plasticity were 0.250 and 0.214, respectively). Within-environment variation (SD) in both foraging traits was not positively correlated with the corresponding plasticity, which indicates that there were no developmental instability costs. More plastic genotypes did not have less extreme trait values than less plastic genotypes for both foraging traits, which indicates that there was no developmental range limit. We conclude that in R. reptans costs of plasticity more strongly constrain evolution of foraging in the horizontal plane (i.e., stolon internode length) than in the vertical plane (i.e., leaf length). 相似文献
6.
7.
8.
9.
Plant phenotypic plasticity belowground: a phylogenetic perspective on root foraging trade-offs 总被引:2,自引:0,他引:2
Many plants proliferate roots in nutrient patches, presumably increasing nutrient uptake and plant fitness. Nutrient heterogeneity has been hypothesized to maintain community diversity because of a trade-off between the spatial extent over which plants forage (foraging scale) and their ability to proliferate roots precisely in nutrient patches (foraging precision). Empirical support for this hypothesis has been mixed, and some authors have suggested that interspecific differences in relative growth rate may be confounded with measurements of foraging precision. We collected previously published data from numerous studies of root foraging ability (foraging precision, scale, response to heterogeneity, and relative growth rate) and phylogenetic relationships for >100 plant species to test these hypotheses using comparative methods. Root foraging precision was phylogenetically and taxonomically conserved. Using a historical and phylogenetically independent contrast correlations, we found no evidence of a root foraging scale-precision trade-off, mixed support for a relative growth rate-precision relationship, and no support for the widespread assumption that foraging precision increases the benefit gained from growth in heterogeneous soil. Our understanding of the impacts of plant foraging precision and soil heterogeneity on plants and communities is less advanced than commonly believed, and we suggest several areas in which further research is needed. 相似文献
10.
11.
Maps of sensory receptor epithelia and computed features of the sensory environment are common elements of auditory, visual, and somatic sensory representations from the periphery to the cerebral cortex. Maps enhance the understanding of normal neural organization and its modification by pathology and experience. They underlie the derivation of the computational principles that govern sensory processing and the generation of perception. Despite their intuitive explanatory power, the functions of and rules for organizing maps and their plasticity are not well understood. Some puzzles of auditory cortical map organization are that few complete receptor maps are available and that even fewer computational maps are known beyond primary cortical areas. Neuroanatomical evidence suggests equally organized connectional patterns throughout the cortical hierarchy that might underlie map stability. Here, we consider the implications of auditory cortical map organization and its plasticity and evaluate the complementary role of maps in representation and computation from an auditory perspective. 相似文献
12.
Frederick Ducatelle Gianni A. Di Caro Alexander Förster Michael Bonani Marco Dorigo Stéphane Magnenat Francesco Mondada Rehan O’Grady Carlo Pinciroli Philippe Rétornaz Vito Trianni Luca M. Gambardella 《Swarm Intelligence》2014,8(1):1-33
We study cooperative navigation for robotic swarms in the context of a general event-servicing scenario. In the scenario, one or more events need to be serviced at specific locations by robots with the required skills. We focus on the question of how the swarm can inform its members about events, and guide robots to event locations. We propose a solution based on delay-tolerant wireless communications: by forwarding navigation information between them, robots cooperatively guide each other towards event locations. Such a collaborative approach leverages on the swarm’s intrinsic redundancy, distribution, and mobility. At the same time, the forwarding of navigation messages is the only form of cooperation that is required. This means that the robots are free in terms of their movement and location, and they can be involved in other tasks, unrelated to the navigation of the searching robot. This gives the system a high level of flexibility in terms of application scenarios, and a high degree of robustness with respect to robot failures or unexpected events. We study the algorithm in two different scenarios, both in simulation and on real robots. In the first scenario, a single searching robot needs to find a single target, while all other robots are involved in tasks of their own. In the second scenario, we study collective navigation: all robots of the swarm navigate back and forth between two targets, which is a typical scenario in swarm robotics. We show that in this case, the proposed algorithm gives rise to synergies in robot navigation, and it lets the swarm self-organize into a robust dynamic structure. The emergence of this structure improves navigation efficiency and lets the swarm find shortest paths. 相似文献
13.
14.
Nestmate foraging activation and interspecific variation in foraging activation is poorly understood in bumble bees, as compared
to honey bees and stingless bees. We therefore investigated olfactory information flow and foraging activation in the New
World bumble bee species, Bombus impatiens. We (1) tested the ability of foragers to associate forager-deposited odor marks with rewarding food, (2) determined whether
potential foragers will seek out the food odor brought back by a successful forager, and (3) examined the role of intranidal
tactile contacts in foraging activation. Bees learned to associate forager-deposited odor marks with rewarding food. They
were significantly more attracted to an empty previously rewarding feeder presented at a random position within an array of
eight previously non-rewarding feeders. However, foragers did not exhibit overall odor specificity for short-term, daily floral
shifts. For two out of three tested scents, activated foragers did not significantly prefer the feeder providing the same
scent as that brought back by a successful forager. Finally, bees contacted by the successful forager inside the nest were
significantly more likely to leave the nest to forage (38.6% increase in attempts to feed from empty feeders) than were non-contacted
bees. This is the first demonstration that tactile contact, a hypothesized evolutionary basal communication mechanism in the
social corbiculate bees, is involved in bumble bee foraging activation.
Received 4 September 2007; revised 30 May 2008; accepted 15 July 2008. 相似文献
15.
Forager honeybees returning to the hive after a successful foraging trip unload the collected liquid to recipient hivemates through mouth-to-mouth food exchange contacts (trophallaxis). The speed at which the liquid is transferred (unloading rate) from donor to recipient is related to the profitability offered by the recently visited food source. Two of the main characteristics that define food source profitability are the flow of solution delivered by the feeder and the time invested by the forager feeding at the source (feeding time). To investigate which of these two variables is related to unloading rate, we individually trained donor foragers to a regulated-flow feeder that presented changes in the delivered flow of solution within a single foraging bout, while feeding time remained constant. With the range of flows used, bees attained maximum crop loads in all experiments. During the subsequent trophallactic encounter with an unfed recipient hivemate, unloading rate was differentially affected by the changes in flow of solution presented during the previous foraging trip at the source, depending on whether there had been an increase or a decrease of flow rate within that visit. Foragers unloaded at lower rates when they experienced a decrease in flow rate, but did not increase the unloading rate when presented with an increase at the food source. Thus, forager honeybees seem to be able to detect variations in the delivered flow of solution, since they modulate unloading rate in relation to these changes, although decreases in food value seem to be perceptually weighted in relation to increases, independently of the time invested in the food-gathering process. 相似文献
16.
Clifton B. Ruehl Thomas J. DeWitt 《Journal of experimental marine biology and ecology》2007,349(2):284-294
Matching behavior, morphology, or physiology to current environments based on experience or cues can be an adaptive solution to environmental change. We examined morphological and behavioral plasticity induced by durophagy (consumption of hard foods) in red drum (Sciaenops ocellatus), an ecologically and recreationally important fish species undergoing stock enhancement. At the conclusion of the experiment, we conducted feeding performance trials to address the potential adaptive significance of diet-induced traits. Relative to soft foods, hard food induced a deeper head in the area of the pharyngeal mill, anterio-dorsally shifted eyes, and 8% heavier feeding muscles in juvenile S. ocellatus. These fish initially consumed hard food 2.6 times faster than fish raised on soft food. However, in subsequent feeding trials, handling time rapidly converged until both groups appeared equally efficient. This result indicates that learning may compensate for small magnitude morphological differences within a species. We discuss the importance of performance trials for testing the adaptive significance of induced plasticity and the value of separating behavioral and morphological development in studies of phenotypic plasticity. We conclude with a discussion on the implications of our results for successful supplementation of wild populations. 相似文献
17.
Informational losses in neuronal nets(NN) with plastic elements were estimated. These losses are related with 1) transition from "complicated" decoding when from the modification state of such elements information of the whole set of recorded elements is extracted to "simple" decoding natural of NN functioning when information is extracted independently for individual events; 2) uncertainty concerning NN structure, if at decoding in one of the modification states the neuron reactivity totally or the weight of plastic synapse equals zero. After the transition from complicated to simple decoding these losses for gradual plasticity are so great that NN with such plasticity has no advantages in informational capacity as compared to the binary one. These losses are absent for plasticity of Olbus type. They are relatively high for neuronal plasticity of Hebb type. For Hebb synapses their value essentially depends on the net parameters. 相似文献
18.
We propose a novel, information-theoretic, characterisation of cascades within the spatiotemporal dynamics of swarms, explicitly measuring the extent of collective communications. This is complemented by dynamic tracing of collective memory, as another element of distributed computation, which represents capacity for swarm coherence. The approach deals with both global and local information dynamics, ultimately discovering diverse ways in which an individual's spatial position is related to its information processing role. It also allows us to contrast cascades that propagate conflicting information with waves of coordinated motion. Most importantly, our simulation experiments provide the first direct information-theoretic evidence (verified in a simulation setting) for the long-held conjecture that the information cascades occur in waves rippling through the swarm. Our experiments also exemplify how features of swarm dynamics, such as cascades' wavefronts, can be filtered and predicted. We observed that maximal information transfer tends to follow the stage with maximal collective memory, and principles like this may be generalised in wider biological and social contexts. 相似文献
19.
Organisms can have divergent paths of development leading to alternative phenotypes, or morphs. The choice of developmental path may be set by environmental cues, the individual's genotype, or a combination of the two. Using individual-based simulation and analytical investigation, we explore the idea that from the viewpoint of a developmental switch, genetic morph determination can sometimes be regarded as adaptive developmental plasticity. We compare the possibilities for the evolution of environmental and genetic morph determination and combinations of the two in situations with spatial variation in conditions. We find that the accuracy of environmental cues in predicting coming selective conditions is important for environmental morph determination, in accordance with previous results, and that genetic morph determination is favored in a similar way by the accuracy of genetic cues, in the form of selectively maintained gene frequency differences between local populations. Restricted gene flow and strong selection acting on the phenotypic alternatives produce clearer gene frequency differences and lead to greater accuracy of genetic cues. For combined environmental and genetic morph determination, we show that the developmental machinery can evolve toward efficiently combining information in environmental and genetic cues for the purpose of predicting coming selective conditions. 相似文献
20.
作为一种有节律的神经活动,神经振荡现象发生在所有的神经系统中,例如大脑皮层、海马、皮层下神经核团以及感觉器官.本综述首先给出了已有的研究结果,即基于theta和gamma频段的同步神经振荡揭示了认知过程的起源与本质,如学习与记忆.然后介绍了关于神经振荡分析的新技术和算法,如表征神经元突触可塑性的神经信息流方向指数,并例... 相似文献