scholarly journals The Evolution of Cooperation in One-Dimensional Mobile Populations with Deterministic Dispersal

Games ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Igor V. Erovenko
Keyword(s):  
High Mobility ◽  
Stochastic Simulations ◽  
Evolution Of Cooperation ◽  
Dispersal Patterns ◽  
Worst Case ◽  
One Dimensional ◽  
Current State ◽  
Size Population ◽  
Spatially Structured Population ◽  
State Of The Environment

I investigate how different dispersal patterns affect the evolution of cooperation in a spatially-structured population. I consider a finite fixed-size population of cooperators and free-riders residing on a one-dimensional lattice with periodic boundaries. Individuals interact via a multiplayer game, which is a version of a public goods game, and the population evolves via a Moran process. Individuals try to improve their interactions by evaluating the current state of the environment and moving to locations with better payoffs. I ran stochastic simulations of the evolution of this Markov process and found that if individuals disperse deterministically to locations with the best payoffs, then cooperation can still be maintained even in the worst-case scenarios, albeit at reduced levels compared to the better-case scenarios. This contrasts with an earlier investigation of probabilistic dispersal patterns, which resulted in the breakdown of cooperation in sparse populations with small interaction neighborhoods, a high mobility rate, and a large dispersal range.

Using Tolerance-Maps to Generate Frequency Distributions of Clearance and Allocate Tolerances for Pin-Hole Assemblies

2007 ◽  
Vol 7 (4) ◽  
pp. 347-359 ◽  
Author(s):  
Gaurav Ameta ◽  
Joseph K. Davidson ◽  
Jami J. Shah
Keyword(s):  
Mathematical Model ◽  
Statistical Method ◽  
Frequency Distribution ◽  
Probabilistic Representation ◽  
Worst Case ◽  
Frequency Distributions ◽  
One Dimensional ◽  
Material Condition ◽  
Geometric Tolerances ◽  
Case Basis

A new mathematical model for representing the geometric variations of lines is extended to include probabilistic representations of one-dimensional (1D) clearance, which arise from positional variations of the axis of a hole, the size of the hole, and a pin-hole assembly. The model is compatible with the ASME/ ANSI/ISO Standards for geometric tolerances. Central to the new model is a Tolerance-Map (T-Map) (Patent No. 69638242), a hypothetical volume of points that models the 3D variations in location and orientation for a segment of a line (the axis), which can arise from tolerances on size, position, orientation, and form. Here, it is extended to model the increases in yield that occur when maximum material condition (MMC) is specified and when tolerances are assigned statistically rather than on a worst-case basis; the statistical method includes the specification of both size and position tolerances on a feature. The frequency distribution of 1D clearance is decomposed into manufacturing bias, i.e., toward certain regions of a Tolerance-Map, and into a geometric bias that can be computed from the geometry of multidimensional T-Maps. Although the probabilistic representation in this paper is built from geometric bias, and it is presumed that manufacturing bias is uniform, the method is robust enough to include manufacturing bias in the future. Geometric bias alone shows a greater likelihood of small clearances than large clearances between an assembled pin and hole. A comparison is made between the effects of choosing the optional material condition MMC and not choosing it with the tolerances that determine the allowable variations in position.

Efficient Analysis of a Catenary Riser

2006 ◽  
Author(s):  
Elizabeth Passano ◽  
Carl M. Larsen
Keyword(s):  
Operating Conditions ◽  
Stochastic Simulations ◽  
Worst Case ◽  
Nonlinear Structure ◽  
Tension Response ◽  
Extreme Response ◽  
Analysis Strategies ◽  
Low Tension ◽  
Term Response

The paper deals with the challenge of predicting the extreme response of catenary risers, a topic of both industry and academic interest. Large heave motions introduced at the upper end of a catenary riser can lead to compression and large bending moments in the region immediately above the touch down area. In the worst case, dynamic beam buckling may occur. The focus of the paper will be on understanding the riser behaviour in extreme, low-tension response and in establishing suitable analysis strategies to predict the extreme response. Results from long nonlinear stochastic simulations of many sea states with varying environmental and operating conditions may be combined to describe the long-term response of a nonlinear structure such as a catenary riser. However, this theoretically straight-forward approach is very demanding computationally and ways to limit the extent of nonlinear stochastic simulations are therefore sought. The usefulness of simpler methods such as regular wave analysis to improve understanding of the physical behaviour and to aid in concentrating the nonlinear simulations to where they are most useful, will be demonstrated.

scholarly journals Imitating a Safe Human Driver Behaviour in Roundabouts Through Deep Learning

2020 ◽  
Vol 19 (1) ◽  
pp. 85-88
Author(s):  
A. S. J. Cervera ◽  
F. J. Alonso ◽  
F. S. García ◽  
A. D. Alvarez
Keyword(s):  
Machine Learning ◽  
Deep Learning ◽  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Driver Behaviour ◽  
Safety Issues ◽  
Current State ◽  
Surrounding Environment ◽  
Human Driver ◽  
State Of The Environment

Roundabouts provide safe and fast circulation as well as many environmental advantages, but drivers adopting unsafe behaviours while circulating through them may cause safety issues, provoking accidents. In this paper we propose a way of training an autonomous vehicle in order to behave in a human and safe way when entering a roundabout. By placing a number of cameras in our vehicle and processing their video feeds through a series of algorithms, including Machine Learning, we can build a representation of the state of the surrounding environment. Then, we use another set of Deep Learning algorithms to analyze the data and determine the safest way of circulating through a roundabout given the current state of the environment, including nearby vehicles with their estimated positions, speeds and accelerations. By watching multiple attempts of a human entering a roundabout with both safe and unsafe behaviours, our second set of algorithms can learn to mimic the human’s good attempts and act in the same way as him, which is key to a safe implementation of autonomous vehicles. This work details the series of steps that we took, from building the representation of our environment to acting according to it in order to attain safe entry into single lane roundabouts.

A Context-Based and Policy-Driven Method to Design and Develop Composite Web Services

2010 ◽  
pp. 310-328
Author(s):  
Zakaria Maamar ◽  
Djamal Benslimane
Keyword(s):  
Web Services ◽  
User Needs ◽  
Design And Development ◽  
Graphical Notation ◽  
Current State ◽  
Behavior Specification ◽  
Composite Web Services ◽  
Composition Operations ◽  
State Of The Environment ◽  
Development Methods

Web services are nowadays attracting the attention of both academia and industry. However, a very little has so far been accomplished in terms of design and development methods that assist those who are responsible for specifying and running applications based on Web services. For this purpose, we developed CP4WS that stands for Context and Policy for Web Services. CP4WS is a context-based and policy-driven method for designing and developing composite Web services. Policies manage various aspects related to Web services like participation in composition and adjustment due to changes in the environment, and context provides the necessary information that enables for instance to trigger the appropriate policies and to regulate the interactions between Web services according to the current state of the environment. CP4WS consists of several steps such as user needs identification and Web services behavior specification. Each step has a specific graphical notation that facilitates the representation, description, and validation of the composition operations of Web services. A running scenario that illustrates the use of CP4WS is presented in the article as well.

Validation of the ANL Plant Dynamics Code With the SNL S-CO2 Loop Transient Data

2013 ◽  
Author(s):  
Anton Moisseytsev ◽  
James J. Sienicki
Keyword(s):  
System Level ◽  
Small Scale ◽  
Dimensional System ◽  
Brayton Cycle ◽  
One Dimensional ◽  
Current State ◽  
Plant Dynamics ◽  
Transient Data ◽  
Experimental Runs ◽  
Good Agreement

The ANL Plant Dynamics Code (PDC) is the current state-of-the-art capability for one-dimensional system level transient analysis of supercritical carbon dioxide (S-CO2) Brayton cycle power converters. Earlier validation of code models was carried out with data from testing of individual S-CO2 components such as a small-scale compact diffusion-bonded heat exchanger and compressor tests. The steady-state part of the PDC has been compared with experimental data from the Sandia National Laboratories (SNL) small-scale S-CO2 Brayton cycle demonstration. In this work, predictions of the PDC code are assessed through comparison with SNL S-CO2 loop transient data. Code modifications were needed to properly simulate the actual experimental runs due to the unique features of the small-scale SNL loop. Overall, good agreement with the measured data is predicted by the PDC, although the code predictions could be improved in some cases. Future code improvements for comparisons with future SNL loop data are identified based upon the results.

Intelligent Algorithm for Biped Robot for Harvesting Watermelons

1999 ◽  
Vol 11 (3) ◽  
pp. 183-192 ◽  
Author(s):  
Ken'ichi Ogasawara ◽  
◽  
Masaki Arao ◽  
Shigeyasu Kawaji ◽  
◽  
...  
Keyword(s):  
Control Strategy ◽  
A Priori ◽  
High Mobility ◽  
Biped Robot ◽  
Bipedal Locomotion ◽  
Intelligent Algorithm ◽  
Biped Robots ◽  
Farm Work ◽  
Current State ◽  
Locomotion Rhythm

Farm working usually involves a harsh environment such as limited work space and soft, unstable or uneven surfaces. High mobility even in such an environment is essential for automating agricultural tasks. Bipedal locomotion is an example of such mobility, but it is statically unstable. Biped robots for farm work must be controlled dynamically to maintain unstable equilibrium. No decisive control strategy for this problem had been mapped. Noting that biped locomotion is periodic and governed by a characteristic rhythm, we proposed control strategy based on locomotion rhythm. In an uncertain environment, the reference rhythm should be modified corresponding to its current state for realizing stable walking. We introduce the concept of ""compliance"" in our rhythm-based locomotion control to modify a priori defined reference rhythm so that the robot maintains its balance. Simulations and experiments demonstrate the feasibility of stable walking in an unfavorably environment.

scholarly journals A TWO-PARAMETER METHOD FOR CHAOS CONTROL AND TARGETING IN ONE-DIMENSIONAL MAPS

2013 ◽  
Vol 23 (01) ◽  
pp. 1350003 ◽  
Author(s):  
DANIEL FRANCO ◽  
EDUARDO LIZ
Keyword(s):  
Chaos Control ◽  
Point Of View ◽  
Positive Equilibrium ◽  
Parameter Method ◽  
One Dimensional ◽  
Current State ◽  
Control Scheme ◽  
The Difference ◽  
One Dimensional Maps ◽  
Parameter Values

We investigate a method of chaos control in which intervention is proportional to the difference between the current state and a fixed value. We prove that this method allows to stabilize the most usual one-dimensional maps used in discrete-time models of population dynamics about a globally stable positive equilibrium. From the point of view of targeting, this technique is very flexible, and we show how to choose the control parameter values to lead the system towards the desired target. Another important feature of this control scheme in the ecological context is that it can be designed to prevent the risk of extinction in models with the so-called Allee effect. We provide a useful geometrical interpretation, and give some examples to illustrate our theoretical results.

scholarly journals The phenomenon of cybercrime in modern criminological theory

2020 ◽  
pp. 401-404
Author(s):  
Ihor Kharytonenko
Keyword(s):  
Information Security ◽  
Sharp Increase ◽  
High Mobility ◽  
Criminological Theory ◽  
Information Space ◽  
High Tech ◽  
Cyber Threats ◽  
Current State ◽  
Domestic Legislation ◽  
High Level

The article considers the concepts and signs of cybercrime, the phenomenon of cybercrime through the prism of indicators thatcharacterize it, in particular the level, dynamics, structure. The social conditionality and the current state are determined taking intoaccount various factors that influence the change of quantitative and qualitative indicators. Globalism, a high level of public danger andthe massive consequences of cyber threats are emphasized.It is pointed out that the scale of threats to the information space is not limited to the borders of one country, as modern globalcomputer networks cover the vast majority of countries, which further contributes to a sharp increase in criminal computer professiona lism and high mobility of criminals. Therefore, it is timely to study and analyze the system of rapidly changing high-tech cyberthreats, tactics of interaction in the field of information security, which affects the formation of sustainable development of society, thefunctioning of mechanisms to counter information threats taking into account modern realities.The signs of the phenomenon of cybercrime through the prism of indicators that characterize it are highlighted:– the scale of threats to the information space is not limited to the borders of one state;– changes in the quantitative and qualitative indicators of cybercrime, in particular a sharp increase in criminal computer professionalismand high mobility of criminals;– the level of cybercrime is closely related to the economic level of development of society in different countries and regions;– cyber threats are fast-changing and high-tech;– high level of latency;– the dependence of the geography of distribution on the factor of urbanization;– Cybercrime is a social phenomenon that manifests itself in a set of cybercrimes.It is noted that in order to prevent these crimes it is necessary to conduct further research in social and criminological areas to studythe psychophysiological properties of cybercriminals, improve domestic legislation in the field of state secrets and official information,international cooperation in information security, improve the content of higher education information security professionals states.

scholarly journals Environmental stewardship as a dimension of a Christian stewardship ethic: views of seminary students, lecturers and ministers

2016 ◽  
Vol 81 (2) ◽  
pp. 44-60
Author(s):  
Cheryl Le Roux ◽  
Keyword(s):  
Environmental Stewardship ◽  
Christian Faith ◽  
Seminary Students ◽  
Reformed Church ◽  
Current State ◽  
The Earth ◽  
Training Programmes ◽  
State Of The Environment ◽  
The Church ◽  
Church Teaching

It is not uncommon to find that Christians are blamed for contributing to the destruction of the environment – a view that derives from the Biblical precept that ‘man was given dominion over the earth’ (cf. Gen. 1:28). The current state of the environment indicates that humankind has indeed ravaged the earth, but it could be argued that this has occurred through greed, covetousness, materialism, competitiveness and short-sightedness which are specific human traits in conflict with God and Christianity. Furthermore, the true significance of the ‘dominion over the earth’ tenet is invariably overlooked. Having dominion over the earth means that man has the responsibility of representing God on earth; of ruling as His co-regents or, put differently, acting as His stewards or custodians of His creation. It is argued that environmental stewardship is a dimension of the Christian stewardship ethic that is inherent in the Christian faith. This article reports on research undertaken with ministers, lecturers and students of the United Reformed Church in Southern Africa who were asked to provide their views on Christian stewardship as a requisite component of their role as leaders and aspirant leaders in the Church. Perspectives on environmental stewardship as a dimension of the Christian stewardship ethic were also probed. The research showed that respondents were unanimous in their understanding that Christian stewardship is Biblically founded and mandated and that environmental stewardship is part of that ethic. However, environmental stewardship is inadequately provided for in Church teaching and seminary training programmes. This article examines respondents’ views on the above and puts forward ways in which environmental stewardship could be enhanced and promoted. Dit is nie ongewoon dat Christene daarvoor geblameer word dat hulle bydra tot die vernietiging van die omgewing nie – ʼn beskouing wat afkomstig is van die Bybelse voorskrif dat “die mens heerskappy oor die aarde gegee is” (vgl. Gen. 1:28). Die huidige toestand waarin die omgewing verkeer dui daarop dat die mens inderdaad die aarde verniel het. Daar kan egter aangevoer word dat hebsug, gierigheid, materialisme, mededingendheid en kortsigtigheid, wat spesifieke menslike eienskappe is wat in konflik met God en met Christenskap is, hiertoe aanleiding gegee het. Die ware betekenis van die beginsel van “heerskappy oor die aarde” word boonop keer op keer misgekyk. Om heerskappy oor die aarde te hê beteken dat die mens die verantwoordelikheid het om God se verteenwoordigers op aarde te wees; om as Sy medeheersers te regeer of, anders gestel, as Sy toesighouers of bewaarders van Sy skepping op te tree. Daar word aangevoer dat rentmeesterskap van die omgewing ʼn dimensie van die Christelike rentmeesterskapsetos is wat eie aan die Christelike geloof is. Hierdie artikel doen verslag oor navorsing wat onder predikante, dosente en studente van die Verenigende Gereformeerde Kerk in Suider-Afrika gedoen is. Die deelnemers is gevra om hul menings te gee oor Christelike rentmeesterskap as ʼn noodsaaklike komponent van hul rol as leiers en aspirantleiers in die kerk. Perspektiewe oor omgewingsrentmeesterskap as ʼn dimensie van die Christelike rentmeesterskapsetos is ook ondersoek. Die navorsing het getoon dat respondente eensgesind was ten opsigte van hul siening dat Christelike rentmeesterskap op die Bybel gegrond is en Bybelse mandaat het, en dat omgewingsrentmeesterskap deel is van daardie etos. Daar word egter nie na behore vir omgewingsrentmeesterskap voorsiening gemaak in die kerk se onderrig- en seminariese opleidingsprogramme nie. Hierdie artikel bestudeer respondente se sienings oor die bogenoemde en stel maniere voor waarop omgewingsrentmeesterskap versterk en bevorder kan word.

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