| | SLO | ENG | Piškotki in zasebnost

Večja pisava | Manjša pisava

Iskanje po katalogu digitalne knjižnice Pomoč

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


21 - 30 / 61
Na začetekNa prejšnjo stran1234567Na naslednjo stranNa konec
21.
An evolutionary inspection game with labour unions on small-world networks
Salahuddin M. Kamal, Yas Al-Hadeethi, Fouad A. Abolaban, Fahad M. Al-Marzouki, Matjaž Perc, 2015, izvirni znanstveni članek

Opis: We study an evolutionary inspection game where agents can chose between working and shirking. The evolutionary process is staged on a small-world network, through which agents compare their incomes and, based on the outcome, decide which strategy to adopt. Moreover, we introduce union members that have certain privileges, of which the extent depends on the bargaining power of the union. We determine how the union affects the overall performance of the firm that employs the agents, and what are its influences on the employees. We find that, depending on its bargaining power, the union has significant leverage to deteriorate the productivity of a firm, and consequently also to lower the long-run benefits of the employees.
Ključne besede: cooperation, public goods, inspection, unions, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 358; Prenosov: 188
.pdf Celotno besedilo (568,84 KB)
Gradivo ima več datotek! Več...

22.
A double-edged sword: benefits and pitfalls of heterogeneous punishment in evolutionary inspection games
Matjaž Perc, Attila Szolnoki, 2015, izvirni znanstveni članek

Opis: As a simple model for criminal behavior, the traditional two-strategy inspection game yields counterintuitive results that fail to describe empirical data. The latter shows that crime is often recurrent, and that crime rates do not respond linearly to mitigation attempts. A more apt model entails ordinary people who neither commit nor sanction crime as the third strategy besides the criminals and punishers. Since ordinary people free-ride on the sanctioning efforts of punishers, they may introduce cyclic dominance that enables the coexistence of all three competing strategies. In this setup ordinary individuals become the biggest impediment to crime abatement. We therefore also consider heterogeneous punisher strategies, which seek to reduce their investment into fighting crime in order to attain a more competitive payoff. We show that this diversity of punishment leads to an explosion of complexity in the system, where the benefits and pitfalls of criminal behavior are revealed in the most unexpected ways. Due to the raise and fall of different alliances no less than six consecutive phase transitions occur in dependence on solely the temptation to succumb to criminal behavior, leading the population from ordinary people-dominated across punisher-dominated to crime-dominated phases, yet always failing to abolish crime completely.
Ključne besede: crime, phase transition, social dilemma, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 290; Prenosov: 232
.pdf Celotno besedilo (1,62 MB)
Gradivo ima več datotek! Več...

23.
Stability of cooperation under image scoring in group interactions
Heinrich H. Nax, Matjaž Perc, Attila Szolnoki, Dirk Helbing, 2015, izvirni znanstveni članek

Opis: Image scoring sustains cooperation in the repeated two-player prisoner's dilemma through indirect reciprocity, even though defection is the uniquely dominant selfish behaviour in the one-shot game. Many real-world dilemma situations, however, firstly, take place in groups and, secondly, lack the necessary transparency to inform subjects reliably of others' individual past actions. Instead, there is revelation of information regarding groups, which allows for "group scoring" but not for image scoring. Here, we study how sensitive the positive results related to image scoring are to information based on group scoring. We combine analytic results and computer simulations to specify the conditions for the emergence of cooperation. We show that under pure group scoring, that is, under the complete absence of image-scoring information, cooperation is unsustainable. Away from this extreme case, however, the necessary degree of image scoring relative to group scoring depends on the population size and is generally very small. We thus conclude that the positive results based on image scoring apply to a much broader range of informational settings that are relevant in the real world than previously assumed.
Ključne besede: public goods, group interactions, phase transition, social dilemma, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 595; Prenosov: 218
.pdf Celotno besedilo (329,32 KB)
Gradivo ima več datotek! Več...

24.
Evolution of public cooperation in a monitored society with implicated punishment and within-group enforcement
Xiaojie Chen, Tatsuya Sasaki, Matjaž Perc, 2015, izvirni znanstveni članek

Opis: Monitoring with implicated punishment is common in human societies to avert freeriding on common goods. But is it effective in promoting public cooperation? We show that the introduction of monitoring and implicated punishment is indeed effective, as it transforms the public goods game to a coordination game, thus rendering cooperation viable in infinite and finite well-mixed populations. We also show that the addition of within-group enforcement further promotes the evolution of public cooperation. However, although the group size in this context has nonlinear effects on collective action, an intermediate group size is least conductive to cooperative behaviour. This contradicts recent field observations, where an intermediate group size was declared optimal with the conjecture that group-size effects and within-group enforcement are responsible. Our theoretical research thus clarifies key aspects of monitoring with implicated punishment in human societies, and additionally, it reveals fundamental group-size effects that facilitate prosocial collective action.
Ključne besede: cooperation, public goods, punishment, sustainable development, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 359; Prenosov: 216
.pdf Celotno besedilo (1,50 MB)
Gradivo ima več datotek! Več...

25.
Different reactions to adverse neighborhoods in games of cooperation
Chunyan Zhang, Jianlei Zhang, Franz Weissing, Matjaž Perc, Guangming Xie, Long Wang, 2012, izvirni znanstveni članek

Opis: In social dilemmas, cooperation among randomly interacting individuals is often difficult to achieve. The situation changes if interactions take place in a network where the network structure jointly evolves with the behavioral strategies of the interacting individuals. In particular, cooperation can be stabilized if individuals tend to cut interaction links when facing adverse neighborhoods. Here we consider two different types of reaction to adverse neighborhoods, and all possible mixtures between these reactions. When faced with a gloomy outlook, players can either choose to cut and rewire some of their links to other individuals, or they can migrate to another location and establish new links in the new local neighborhood. We find that in general local rewiring is more favorable for the evolution of cooperation than emigration from adverse neighborhoods. Rewiring helps to maintain the diversity in the degree distribution of players and favors the spontaneous emergence of cooperative clusters. Both properties are known to favor the evolution of cooperation on networks. Interestingly, a mixture of migration and rewiring is even more favorable for the evolution of cooperation than rewiring on its own. While most models only consider a single type of reaction to adverse neighborhoods, the coexistence of several such reactions may actually be an optimal setting for the evolution of cooperation.
Ključne besede: cooperation, public goods, phase transitions, social dilemmas, coevolution, physics of social systems
Objavljeno: 19.06.2017; Ogledov: 486; Prenosov: 220
.pdf Celotno besedilo (481,90 KB)
Gradivo ima več datotek! Več...

26.
Equivalences in biological and economical systems
Hugh Trenchard, Matjaž Perc, 2016, izvirni znanstveni članek

Opis: An interdisciplinary bridge is proposed between principles of collective behavior in biological systems, particularly bicycle pelotons, and the economic phenomenon called the rebound effect. Two main equivalencies are proposed between aspects of peloton dynamics and aspects of energy service efficiencies and the rebound effect. Firstly, a threshold whereby weaker cyclists, up to maximal capacities, sustain speeds of pacesetters by drafting; equivalent to a threshold whereby consumers will not exceed maximum allocated budgets for energy services, costs for which are externally determined. Secondly, a threshold of peloton dynamics whereby, below this threshold, weaker cyclists share costly non-drafting positions, whereas above this threshold cyclists cannot share these positions but can sustain pacesetter speeds. This is in turn equivalent to the threshold in the context of energy service efficiency, whereby consumers will increase spending to the limit indicated by the rebound magnitude but not to their maximum allocated budgets. These thresholds are a consequence of the model equations, and the latter threshold is explained by consumer apprehension that existing energy efficiencies could disappear or be negative, when consumers would be over budget. This partly explains long term rebound increase, whereby consumers increase consumption as confidence rises that cost savings due to energy service efficiency is stable.
Ključne besede: cycling, peloton, rebound effect, physics of social systems
Objavljeno: 19.06.2017; Ogledov: 247; Prenosov: 52
.pdf Celotno besedilo (691,09 KB)
Gradivo ima več datotek! Več...

27.
Understanding recurrent crime as system-immanent collective behavior
Matjaž Perc, Karsten Donnay, Dirk Helbing, 2013, izvirni znanstveni članek

Opis: Containing the spreading of crime is a major challenge for society. Yet, since thousands of years, no effective strategy has been found to overcome crime. To the contrary, empirical evidence shows that crime is recurrent, a fact that is not captured well by rational choice theories of crime. According to these, strong enough punishment should prevent crime from happening. To gain a better understanding of the relationship between crime and punishment, we consider that the latter requires prior discovery of illicit behavior and study a spatial version of the inspection game. Simulations reveal the spontaneous emergence of cyclic dominance between criminals, inspectors, and ordinary people as a consequence of spatial interactions. Such cycles dominate the evolutionary process, in particular when the temptation to commit crime or the cost of inspection are low or moderate. Yet, there are also critical parameter values beyond which cycles cease to exist and the population is dominated either by a stable mixture of criminals and inspectors or one of these two strategies alone. Both continuous and discontinuous phase transitions to different final states are possible, indicating that successful strategies to contain crime can be very much counter-intuitive and complex. Our results demonstrate that spatial interactions are crucial for the evolutionary outcome of the inspection game, and they also reveal why criminal behavior is likely to be recurrent rather than evolving towards an equilibrium with monotonous parameter dependencies.
Ključne besede: crime, evolutionary games, collective phenomena, phase transitions, statistical physics
Objavljeno: 19.06.2017; Ogledov: 518; Prenosov: 220
.pdf Celotno besedilo (433,51 KB)
Gradivo ima več datotek! Več...

28.
Beyond pairwise strategy updating in the prisoner's dilemma game
Xiaofeng Wang, Matjaž Perc, Yongkui Liu, Xiaojie Chen, Long Wang, 2012, izvirni znanstveni članek

Opis: In spatial games players typically alter their strategy by imitating the most successful or one randomly selected neighbor. Since a single neighbor is taken as reference, the information stemming from other neighbors is neglected, which begets the consideration of alternative, possibly more realistic approaches. Here we show that strategy changes inspired not only by the performance of individual neighbors but rather by entire neighborhoods introduce a qualitatively different evolutionary dynamics that is able to support the stable existence of very small cooperative clusters. This leads to phase diagrams that differ significantly from those obtained by means of pairwise strategy updating. In particular, the survivability of cooperators is possible even by high temptations to defect and over a much wider uncertainty range. We support the simulation results by means of pair approximations and analysis of spatial patterns, which jointly highlight the importance of local information for the resolution of social dilemmas.
Ključne besede: cooperation, social dilemma, wisdom of crowds, phase transitions, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 270; Prenosov: 207
.pdf Celotno besedilo (825,96 KB)
Gradivo ima več datotek! Več...

29.
Biodiversity in models of cyclic dominance is preserved by heterogeneity in site-specific invasion rates
Attila Szolnoki, Matjaž Perc, 2016, izvirni znanstveni članek

Opis: Global, population-wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop. Previous research has shown that such oscillations can emerge if the interaction network has small-world properties, and more generally, because of long-range interactions among individuals or because of mobility. But although these features are all common in nature, global oscillations are rarely observed in actual biological systems. This begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations. Here we show that, although heterogeneous species-specific invasion rates fail to have a noticeable impact on species coexistence, randomness in site-specific invasion rates successfully hinders the emergence of global oscillations and thus preserves biodiversity. Our model takes into account that the environment is often not uniform but rather spatially heterogeneous, which may influence the success of microscopic dynamics locally. This prevents the synchronization of locally emerging oscillations, and ultimately results in a phenomenon where one type of randomness is used to mitigate the adverse effects of other types of randomness in the system.
Ključne besede: biodiversity, cyclic dominance, rock-paper-scissors, physics of social systems
Objavljeno: 23.06.2017; Ogledov: 287; Prenosov: 190
.pdf Celotno besedilo (419,58 KB)
Gradivo ima več datotek! Več...

30.
Chimera states in uncoupled neurons induced by a multilayer structure
Soumen Majhi, Matjaž Perc, Dibakar Ghosh, 2016, izvirni znanstveni članek

Opis: Spatial coexistence of coherent and incoherent dynamics in network of coupled oscillators is called a chimera state. We study such chimera states in a network of neurons without any direct interactions but connected through another medium of neurons, forming a multilayer structure. The upper layer is thus made up of uncoupled neurons and the lower layer plays the role of a medium through which the neurons in the upper layer share information among each other. Hindmarsh-Rose neurons with square wave bursting dynamics are considered as nodes in both layers. In addition, we also discuss the existence of chimera states in presence of inter layer heterogeneity. The neurons in the bottom layer are globally connected through electrical synapses, while across the two layers chemical synapses are formed. According to our research, the competing effects of these two types of synapses can lead to chimera states in the upper layer of uncoupled neurons. Remarkably, we find a density-dependent threshold for the emergence of chimera states in uncoupled neurons, similar to the quorum sensing transition to a synchronized state. Finally, we examine the impact of both homogeneous and heterogeneous inter-layer information transmission delays on the observed chimera states over a wide parameter space.
Ključne besede: complex networks, computational biophysics, nonlinear phenomena, statistical physics
Objavljeno: 23.06.2017; Ogledov: 275; Prenosov: 227
.pdf Celotno besedilo (1,40 MB)
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.19 sek.
Na vrh
Logotipi partnerjev Univerza v Mariboru Univerza v Ljubljani Univerza na Primorskem Univerza v Novi Gorici