scholarly journals Ants determine their next move at rest: motor planning and causality in complex systems

2016 ◽  
Vol 3 (1) ◽  
pp. 150534 ◽  
Author(s):  
Edmund R. Hunt ◽  
Roland J. Baddeley ◽  
Alan Worley ◽  
Ana B. Sendova-Franks ◽  
Nigel R. Franks
Keyword(s):  
Complex Systems ◽  
Animal Movement ◽  
Social Information ◽  
Physiological Mechanism ◽  
Motor Planning ◽  
Division Of Labour ◽  
Chemical Information ◽  
Average Speed ◽  
Eusocial Animals ◽  
The Stability

To find useful work to do for their colony, individual eusocial animals have to move, somehow staying attentive to relevant social information. Recent research on individual Temnothorax albipennis ants moving inside their colony’s nest found a power-law relationship between a movement’s duration and its average speed; and a universal speed profile for movements showing that they mostly fluctuate around a constant average speed. From this predictability it was inferred that movement durations are somehow determined before the movement itself. Here, we find similar results in lone T. albipennis ants exploring a large arena outside the nest, both when the arena is clean and when it contains chemical information left by previous nest-mates. This implies that these movement characteristics originate from the same individual neural and/or physiological mechanism(s), operating without immediate regard to social influences. However, the presence of pheromones and/or other cues was found to affect the inter-event speed correlations. Hence we suggest that ants’ motor planning results in intermittent response to the social environment: movement duration is adjusted in response to social information only between movements, not during them. This environmentally flexible, intermittently responsive movement behaviour points towards a spatially allocated division of labour in this species. It also prompts more general questions on collective animal movement and the role of intermittent causation from higher to lower organizational levels in the stability of complex systems.

The stability of polyelectrolyte complex systems of poly(diallydimethyl-ammonium chloride) with different polyanions

2004 ◽  
Vol 211 (1) ◽  
pp. 121-134 ◽  
Author(s):  
Mandy Mende ◽  
Heide-Marie Buchhammer ◽  
Simona Schwarz ◽  
Gudrun Petzold ◽  
Werner Jaeger
Keyword(s):  
Complex Systems ◽  
Ammonium Chloride ◽  
Polyelectrolyte Complex ◽  
The Stability

The average speed of motion and optimal power consumption in biped robots

2019 ◽  
Vol 34 ◽  
Author(s):  
Vida Shams Esfanabadi ◽  
Mostafa Rostami ◽  
Seyed Mohammadali Rahmati ◽  
Jacky Baltes ◽  
Soroush Sadeghnejad
Keyword(s):  
Power Consumption ◽  
Empirical Evaluation ◽  
Biped Robot ◽  
Walking Ability ◽  
Average Speed ◽  
Optimal Power ◽  
Minimum Power Consumption ◽  
Maximum Stability ◽  
Motion Speed ◽  
The Stability

Abstract One of the issues that have garnered little attention, but that is nevertheless important for developing practical robots, is optimal walking conditions like power consumption during walking. The main contribution of this research is to prepare a correct walking pattern for humans who have a problem with their walking and also study the effect of average motion speed on optimal power consumption. In this study, we firstly optimize the stability and minimize the power consumption of the robot during the single support phase using parameter optimization. Our approach is based on the well-known Zero Moment Point method to calculate the stability of the proposed biped robot. Secondly, we performed experiments on healthy male, age 29 years, to analyze human walking by placing 28 markers, attached to anatomical positions and two power plates for a distance of more than one gait cycle at an average speed of 1.23 ± 0.1 m s−1 validate our results for motion analysis of correct walking ability. Our model was continuously validated by comparing the results of our empirical evaluation against the prediction of our model. The errors between experimental test and our prediction were about 4%–11% for the joint trajectories and about 0.2%–0.5% for the ground reaction forces which is acceptable for our prediction. Due to the presented model and optimized issue and predicted path, the robot can move like a person in a way that has maximum stability along with the minimum power consumption. Finally, the robot was able to walk like a specific person that we considered. This study is a case study and also can be generalized to all samples and can perform these procedures to another person’s with different features.

Modernism, Post Modernism and Organizational Analysis 3: The Contribution of Jacques Derrida

1989 ◽  
Vol 10 (4) ◽  
pp. 479-502 ◽  
Author(s):  
Robert Cooper
Keyword(s):  
Jacques Derrida ◽  
Organization Theory ◽  
Social Systems ◽  
Division Of Labour ◽  
Organizational Analysis ◽  
Formal Organization ◽  
Post Modernism ◽  
Critical Understanding ◽  
Essential Function ◽  
The Stability

This paper, the third in a series on the relevance of the modernist-post modernist debate to organizational analysis (Cooper and Burrell 1988, Burrell 1988), examines the work of Jacques Derrida. Specifically, Derrida's work is viewed as a contribution to the analysis of process (as opposed to structure) in social systems. In this context, three interrelated themes of his work - deconstruction, writing, 'difference' — are described in some detail and their implications explored for social and organizational analysis. Derrida's account of the logic of writing shows it to be fundamental to the division of labour and therefore to significant dimensions (complexity, formalization) of formal organization. Since 'organization theuries' are themselves products of writing and the division of labour, their essential function is to explain and justify the structures they represent, they are therefore more concerned with maintaining their own consistency and the stability of the organized world they describe rather than critical understanding. This point is illustrated by a detailed deconstruction of two major approaches to the study of bureaucracy (the 'formalist' and 'expertise' models) in organization theory. Finally, it is suggested that the affinity between the logic of writing and the division of labour underlies Michel Foucault's concept of knowledge-power and the development of areas of professionalized knowledge such as accountancy.

scholarly journals Car-following Behavior Analysis of Left-turn Vehicles at Signalized Intersections

2020 ◽  
Vol 6 (1) ◽  
pp. 186-193 ◽  
Author(s):  
Fulu Wei ◽  
Long Chen ◽  
Yongqing Guo ◽  
Mingtao Chen ◽  
Jiaxiang Ma
Keyword(s):  
Field Data ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Velocity Difference ◽  
Left Turn ◽  
Average Speed ◽  
Car Following ◽  
Turning Radius ◽  
The Stability ◽  
Stability And Accuracy

In order to enrich the car-following theory of urban signalized intersections, and reveal the car-following characteristics of left turn at signalized intersections, the car-following behavior of left turn at signalized intersections is studied. The car-following data acquisition test which was based on high precision GPS was designed. And the car-following characteristics of left-turning vehicles at signalized intersections with different turning radii were analyzed. Based on which, the influence of radius on the car-following behavior was explained, and the New Full Velocity Difference (NFVD) model was developed. The genetic algorithm was used to calibrate the parameters of the NFVD model. The stability and accuracy of the calibrated model was further analyzed by using field data. The results showed that the average speed of the following car increases with the turning radius of the signalized intersection; the car-following speed which the highest frequency occurs under different turning radii tends to increase with the enlargement of turning radius; the larger the average headway distance between the car-following vehicles, the more intense of the driver’s response to the deceleration of the front vehicle. These findings could be used in traffic simulation and to make engineering decisions.

scholarly journals Common Weak Linear Copositive Lyapunov Functions for Positive Switched Linear Systems

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yuangong Sun ◽  
Zhaorong Wu ◽  
Fanwei Meng
Keyword(s):  
Stability Analysis ◽  
Complex Systems ◽  
Linear Systems ◽  
Algebraic Structure ◽  
Lyapunov Functions ◽  
Sufficient Conditions ◽  
Switched Linear Systems ◽  
Numerical Examples ◽  
The Stability ◽  
Necessary And Sufficient

Lyapunov functions play a key role in the stability analysis of complex systems. In this paper, we study the existence of a class of common weak linear copositive Lyapunov functions (CWCLFs) for positive switched linear systems (PSLSs) which generalize the conventional common linear copositive Lyapunov functions (CLCLFs) and can be used as handy tool to deal with the stability of PSLSs not covered by CLCLFs. We not only establish necessary and sufficient conditions for the existence of CWCLFs but also clearly describe the algebraic structure of all CWCLFs. Numerical examples are also given to demonstrate the effectiveness of the obtained results.

Research on the Robustness of Peer-to-Peer Overlay

2013 ◽  
Vol 427-429 ◽  
pp. 2884-2887
Author(s):  
Zhi Yong Jiang
Keyword(s):  
Complex Systems ◽  
Complex Networks ◽  
Overlay Networks ◽  
Vital Role ◽  
Peer To Peer ◽  
Error Tolerance ◽  
High Price ◽  
Generic Properties ◽  
The Stability

Many complex networks display a surprising degree of tolerance against error comes at a high price in that these networks are extremely vulnerable to attacks (that is , to the removal of a few nodes that play a vital role in the networks). Complex peer-to-peer overlay networks display a surprising degree of robustness: although some components regularly malfunction, local failures rarely lead to the loss of the information carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems components. In this paper a model of peer-to-peer overlay is presented based on the actual topology. According to the model it is found that such error tolerance and attack vulnerability are generic properties of peer-to-peer overlay.

scholarly journals Pollen reinforces learning in honey bee pollen foragers but not in nectar foragers

2020 ◽  
Vol 223 (22) ◽  
pp. jeb230250
Author(s):  
Denise Nery ◽  
Emilia Moreno ◽  
Andrés Arenas
Keyword(s):  
Honey Bees ◽  
Physiological Mechanism ◽  
Simultaneous Presentation ◽  
Division Of Labour ◽  
Proboscis Extension Response ◽  
Reinforced Learning ◽  
Proboscis Extension ◽  
Foraging Specialization ◽  
Better Than

ABSTRACTSearching for reward motivates and drives behaviour. In honey bees Apis mellifera, specialized pollen foragers are attracted to and learn odours with pollen. However, the role of pollen as a reward remains poorly understood. Unlike nectar, pollen is not ingested during collection. We hypothesized that pollen (but not nectar) foragers could learn pollen by sole antennal or tarsal stimulation. Then, we tested how pairing of pollen (either hand- or bee-collected) and a neutral odour during a pre-conditioning affects performance of both pollen and nectar foragers during the classical conditioning of the proboscis extension response. Secondly, we tested whether nectar and pollen foragers perceive the simultaneous presentation of pollen (on the tarsi) and sugar (on the antennae) as a better reinforcement than sucrose alone. Finally, we searched for differences in learning of the pollen and nectar foragers when they were prevented from ingesting the reward during the conditioning. Differences in pollen-reinforced learning correlate with division of labour between pollen and nectar foragers. Results show that pollen foragers performed better than nectar foragers during the conditioning phase after being pre-conditioned with pollen. Pollen foragers also performed better than nectar foragers in both the acquisition and extinction phases of the conditioning, when reinforced with the dual reward. Consistently, pollen foragers showed improved abilities to learn cues reinforced without sugar ingestion. We discussed that differences in how pollen and nectar foragers respond to a cue associated with pollen greatly contribute to the physiological mechanism that underlies foraging specialization in the honeybee.

scholarly journals Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

2017 ◽  
Vol 13 ◽  
pp. 2698-2709 ◽  
Author(s):  
Marco Russo ◽  
Paolo Lo Meo
Keyword(s):  
Complex Systems ◽  
Multiple Equilibria ◽  
Supramolecular Interactions ◽  
Complex Case ◽  
Coulomb Interactions ◽  
Simultaneous Formation ◽  
Conformational Dynamic ◽  
Versatile Tool ◽  
Organic Guests ◽  
The Stability

Polarimetry was used to investigate the binding abilities of a chiral calix[4]resorcinarene derivative, bearing L-proline subunits, towards a set of suitably selected organic guests. The simultaneous formation of 1:1 and 2:1 host–guest inclusion complexes was observed in several cases, depending on both the charge status of the host and the structure of the guest. Thus, the use of the polarimetric method was thoroughly revisited, in order to keep into account the occurrence of multiple equilibria. Our data indicate that the stability of the host–guest complexes is affected by an interplay between Coulomb interactions, π–π interactions, desolvation effects and entropy-unfavorable conformational dynamic restraints. Polarimetry is confirmed as a very useful and versatile tool for the investigation of supramolecular interactions with chiral hosts, even in complex systems involving multiple equilibria.

scholarly journals Loschmidt echo and time reversal in complex systems

2016 ◽  
Vol 374 (2069) ◽  
pp. 20150383 ◽  
Author(s):  
Arseni Goussev ◽  
Rodolfo A. Jalabert ◽  
Horacio M. Pastawski ◽  
Diego A. Wisniacki
Keyword(s):  
Complex Systems ◽  
Time Reversal ◽  
Cold Atoms ◽  
Quantum Evolution ◽  
Many Body ◽  
The Past ◽  
Reversal Procedure ◽  
Physical Effects ◽  
Loschmidt Echo ◽  
The Stability

Echoes are ubiquitous phenomena in several branches of physics, ranging from acoustics, optics, condensed matter and cold atoms to geophysics. They are at the base of a number of very useful experimental techniques, such as nuclear magnetic resonance, photon echo and time-reversal mirrors. Particularly interesting physical effects are obtained when the echo studies are performed on complex systems, either classically chaotic, disordered or many-body. Consequently, the term Loschmidt echo has been coined to designate and quantify the revival occurring when an imperfect time-reversal procedure is applied to a complex quantum system, or equivalently to characterize the stability of quantum evolution in the presence of perturbations. Here, we present the articles which discuss the work that has shaped the field in the past few years.

scholarly journals CONCERNING THE STABILITY OF THE ACID-BASE EQUILIBRIUM OF THE BLOOD IN PREGNANT ANIMALS

1926 ◽  
Vol 43 (1) ◽  
pp. 53-59 ◽  
Author(s):  
William deB. MacNider
Keyword(s):  
Renal Injury ◽  
Physiological State ◽  
Physiological Mechanism ◽  
Gestation Period ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Equilibrium ◽  
Acid Base Equilibrium ◽  
Base Balance ◽  
The Stability

1. The acid-base equilibrium of the blood as indicated by determinations of the reserve alkali of the blood remains constant in non-pregnant animals at different age periods. This statement does not imply that the acid-base balance of such animals at different age periods is a stable balance. 2. In pregnant animals of the same age periods as the control animals there may develop an instability of this equilibrium which is either associated with the occurrence of a renal injury and which may be looked upon as a retention phenomenon, or arises independently of such an injury. In this latter group of animals the disturbance in the equilibrium increases in frequency and is earlier in its appearance in the gestation period as the age of the organism increases. 3. In old and in senile pregnant animals some physiological mechanism other than that of the kidney becomes unable to stabilize the acid-base equilibrium of the blood with the result that as the pregnancy advances this physiological state of the organism (gestation) becomes pathological.

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