ALLEE EFFECT IN POPULATION DYNAMICS: EXISTENCE OF BREATHER-LIKE BEHAVIOR AND CONTROL OF CHAOS THROUGH DISPERSAL

2006 ◽  
Vol 16 (07) ◽  
pp. 2001-2012 ◽  
Author(s):  
DESPINA HADJIAVGOUSTI ◽  
SIMOS ICHTIAROGLOU
Keyword(s):  
Allee Effect ◽  
Chaotic Behavior ◽  
Biological Species ◽  
Control Of Chaos ◽  
Localized Solutions ◽  
A Chain ◽  
Dispersal Probability ◽  
And Control ◽  
Time Periodic ◽  
Nonzero Probability

We consider a one-dimensional chain of identical sites, appropriate for colonization by a biological species. The dynamics at each site is subjected to the demographic Allee effect. We consider nonzero probability p of dispersal to the nearby sites and we prove, for small values of p, the existence of asymptotically stable time-periodic and space-localized solutions, such that the central site carries the vast majority of the metapopulation, while the populations at nearby sites attain very small values. We study numerically a chain of three sites, both for the case of open ends or periodic boundary conditions. We study the bifurcations leading to transition from chaotic to periodic behavior and vice-versa and note that the increase of the dispersal probability in both cases controls the chaotic behavior of the metapopulation.

Removal, Suppression, and Control of Chaos by Nonlinear Design

1995 ◽  
Vol 48 (12) ◽  
pp. 795-808 ◽  
Author(s):  
John F. Lindner ◽  
William L. Ditto
Keyword(s):  
Nonlinear Dynamics ◽  
Nonlinear Oscillator ◽  
Chaotic Behavior ◽  
Dissipative Systems ◽  
Mathematical Notation ◽  
Control Of Chaos ◽  
Physical Experiments ◽  
Nonlinear Design ◽  
Control Equation ◽  
And Control

Techniques to remove, suppress, and control the chaotic behavior of nonlinear systems are reviewed. Analysis of a forced damped nonlinear oscillator provides a brief overview of the relevant nonlinear dynamics of dissipative systems. Various techniques for suppression and control of chaos are then outlined, compared and contrasted. A unified mathematical notation facilitates the comparison. The successes of each strategy in numerical simulations and physical experiments are carefully noted. Their strengths and weaknesses are analyzed, and they are evaluated according to whether they employ feedback, are goal-oriented, are model-based, merely remove chaos–or truly exploit it. An elementary derivation of the important OGY control equation is supplied. Critical references provide an entry into the literature. It is argued that nonlinearity can be a real-world advantage, and it is hoped that this review will serve as summary of, and invitation to, the nascent field of nonlinear design.

Influence of initiation mode on stability and control of a chain reaction

1980 ◽  
Vol 20 (18) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. T. Chen ◽  
P. A. Chartier ◽  
S. Setthachayanon
Keyword(s):  
Chain Reaction ◽  
Stability And Control ◽  
A Chain ◽  
And Control

Design and Analysis of Reduced Degree of Freedom Modular Snake Robot

2017 ◽  
Author(s):  
Peter Racioppo ◽  
Wael Saab ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Three Dimensional ◽  
Cross Sectional ◽  
Design Synthesis ◽  
Snake Robot ◽  
Routing Schemes ◽  
Revolute Joints ◽  
Modular Units ◽  
A Chain ◽  
The Moment ◽  
And Control

This paper presents the design and analysis of an underactuated, cable driven mechanism for use in a modular robotic snake. The proposed mechanism is composed of a chain of rigid links that rotate on parallel revolute joints and are actuated by antagonistic cable pairs and a multi-radius pulley. This design aims to minimize the cross sectional area of cable actuated robotic snakes and eliminate undesirable nonlinearities in cable displacements. A distinctive feature of this underactuated mechanism is that it allows planar serpentine locomotion to be accomplished with only two modular units, improving the snake’s ability to conform to desired curvature profiles and minimizing the control complexity involved in snake locomotion. First, the detailed mechanism and cable routing scheme are presented, after which the kinematics and dynamics of the system are derived and a comparative analysis of cable routing schemes is performed, to assist with design synthesis and control. The moment of inertia of the mechanism is modeled, for future use in the implementation of three-dimensional modes of snake motion. Finally, a planar locomotion strategy for snake robots is devised, demonstrated in simulation, and compared with previous studies.

scholarly journals Neural Networks for Prediction and Control of Chaotic Fluidized Bed Hydrodynamics

Fractals ◽  
1997 ◽  
Vol 05 (03) ◽  
pp. 523-530 ◽  
Author(s):  
R. Bakker ◽  
R. J. de Korte ◽  
J. C. Schouten ◽  
C. M. Van Den Bleek ◽  
F. Takens
Keyword(s):  
Fluidized Bed ◽  
Prediction Error ◽  
Control Of Chaos ◽  
Short Term ◽  
Prediction And Control ◽  
Short Term Prediction ◽  
Capacitance Tomography ◽  
And Control ◽  
Dynamic Invariants ◽  
Tomography Data

A neural-network-based model that has learnt the chaotic hydrodynamics of a fluidized bed reactor is presented. The network is trained on measured electrical capacitance tomography data. A training algorithm is used that does not only minimize the short-term prediction error but also the information needed to synchronize the model with the real system. This forces the model to focus more on learning the longer term dynamics of the system, expressed in the average multi-step-ahead prediction error and dynamic invariants such as correlation entropy and dimension. The availability of the model is an important step towards control of chaos in gas-solid fluidized beds.

Design and Development of a Multi-Module Deployable Manipulator

1999 ◽  
Author(s):  
Kenneth Wong ◽  
Vinod J. Modi ◽  
Clarence W. de Silva ◽  
Arun K. Misra
Keyword(s):  
Real Time ◽  
Experimental Investigations ◽  
Computationally Efficient ◽  
Real Time Control ◽  
Design And Development ◽  
Time Control ◽  
Dynamics And Control ◽  
Manipulator Design ◽  
A Chain ◽  
And Control

Abstract This paper presents the design and development of a Multi-module Deployable Manipulator System (MDMS) as well as a dynamical formulation for it. The system is designed for experimental investigations aimed at dynamics and control of this variable geometry manipulator by implementing different control algorithms to regulate its performance. The manipulator operates in a horizontal plane and is unique in that it comprises of four modules, each of which has one revolute joint and one prismatic joint, connected in a chain topology. Each module has a slewing link of approximately 20cm length and is capable of extending by 15cm. The manipulator design involves the selection and sizing of actuators, the design of mounting and connecting components, and the selection of hardware as well as software for real-time control. The dynamical model is formulated using an O(N) algorithm, based on the Lagrangian approach and velocity transformations. The O(N) character is computationally efficient permitting real-time control of the system.

Critical Control Points of Street-Vended Foods in the Dominican Republic

1988 ◽  
Vol 51 (5) ◽  
pp. 373-383 ◽  
Author(s):  
FRANK L. BRYAN ◽  
SILVIA C. MICHANIE ◽  
PERSIA ALVAREZ ◽  
AURELIO PANIAGUA
Keyword(s):  
Dominican Republic ◽  
Prevention And Control ◽  
Preventive Measures ◽  
Control Points ◽  
Street Vending ◽  
Ambient Temperatures ◽  
Critical Control Points ◽  
Rice Samples ◽  
And Control ◽  
Time Periodic

Hazard analyses were conducted at four street-vending stands in the Dominican Republic. Temperatures of foods were measured during cooking, display (holding), and reheating (when done). Samples were taken at each step of the operation and at 5 to 6-h intervals during display. Foods usually attained temperatures that exceeded 90°C at the geometric center during cooking and reheating. At three of the stands, foods (e.g., fish, chickens, pork pieces) were fried and held until sold. Leftovers were held overnight at ambient temperatures in the home of the vendor or in a locked compartment of the stand. They were usually reheated early in the morning and displayed until sold. During the interval of holding, aerobic mesophilic counts progressively increased with time from about 103 after cooking to between 105 to 109/g. The higher counts were usually associated with holding overnight. Escherichia coli (in water, milk and cheese samples), Bacillus cereus (in bean and rice samples), and Clostridium perfringens (in meat, chicken and bean samples) were isolated, but usually in numbers less than 103/g. At the other stand, foods (e.g. beans, rice, meat and chicken) were cooked just before serving as complete meals. There were no leftovers. This operation was less hazardous, although there were many sanitary deficiencies. Recommendations for prevention and control of microbial hazards (mainly reducing holding time, periodic reheating and requesting reheating just before purchasing) are given. The need and suggestions for implementing educational activities to alert and inform those concerned about hazards and preventive measures are presented.

A New Case Of Dysfibrinogenemia : Isolation Of The Abnormal, Unclottable Fibrinogen Population

1981 ◽  
Author(s):  
M Jandrot-Perrus ◽  
M H Aurousseau ◽  
F Josso
Keyword(s):  
Factor Xiii ◽  
Gel Filtration ◽  
Healthy Woman ◽  
Fibrin Clot ◽  
Elution Volume ◽  
Functional Studies ◽  
Sds Page ◽  
Normal Functional ◽  
A Chain ◽  
And Control

In a 81-year-old healthy woman, gross abnormalities of fibrin formation in routine tests led to the discovery of a dysfibrinogenemia.Abnormal and control fibrinogens were purified in parallel using precipitation by glycine (Kazal) ; final clottability was 95-98 % for the control and 50 % for the patient’s fibrinogen. Electrophoretic behaviour of the fibrinogen momecule, the three chains and the products of fibrin cross-linking by factor XIII a was normal. Functional studies gave the following results : (i) delayed coagulation by thrombin, Reptilase and Venacil with gross abnormalities of the clot; (ii) inhibition of coagulation of normal fibrinogen ; (iii) poor fibrin monomer aggregation (opacimetry) ; (iv) delayed fibrinogen proteolysis by plasmin (SDS-PAGE) . Release of fibrinopeptide A by thrombin was incomplete (RIA).Fibrinogen NH2-terminal residues were found normal, but the presence of ALA-residue in fibrin clot and in the supernatant showed that part of fibrinogen was not clotted, either copolymerized with fibrin or remaining in solution. Gel filtration of the supernatant showed the presence of both soluble complexes and fibrinogen characterized by the elution volume of the peak and NH2-terminal analysis. This fibrinogen population was unclottable by thrombin and inhibited clotting of normal fibrinogen.These preliminary results suggest the existence of a defect on the A-a chain of this abnormal fibrinogen which was called fibrinogen Bondy.

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