scholarly journals Mining Pool Selection under Block WithHolding Attack

2021 ◽  
Vol 11 (4) ◽  
pp. 1617
Author(s):  
Kentaro Fujita ◽  
Yuanyu Zhang ◽  
Masahiro Sasabe ◽  
Shoji Kasahara
Keyword(s):  
Selection Process ◽  
Evolutionary Game ◽  
The Other ◽  
Stable States ◽  
Stable Pool ◽  
Critical Issues ◽  
Evolutionarily Stable ◽  
Pool Population

In current Proof-of-Work (PoW) blockchain systems, miners usually form mining pools to compete with other pools/miners in the mining competition. Forming pools can give miners steady revenues but will introduce two critical issues. One is mining pool selection, where miners select the pools to join in order to maximize their revenues. The other is a Block WithHolding (BWH) attack, where pools can inject part of their hash/mining power into other pools to obtain additional revenues without contributing to the mining process of the attacked pools. Reasoning that the BWH attack will have significant impacts on the pool selection, we therefore investigate the mining pool selection issue in the presence of a BWH attack in this paper. In particular, we model the pool selection process of miners as an evolutionary game and find the Evolutionarily Stable States (ESSs) of the game (i.e., stable pool population states) as the solutions. Previous studies investigated this problem from the perspective of pool managers and neglected the revenues from attacked pools (attacking revenues), leading to less accurate and insightful findings. This paper, however, focuses on the payoffs of miners and carefully takes the attacking revenues into consideration. To demonstrate how the problem is solved, we consider the scenario with two mining pools and further investigate the case where one pool attacks the other and the case where the two pools attack each other. The results in this paper show that pools can attract more miners to join by launching a BWH attack and the attack power significantly affects the stable pool populations.

scholarly journals Coexisting with cheaters: Microbial exoenzyme production as a snowdrift game model

2021 ◽  
Author(s):  
Constantinos Xenophontos ◽  
Stanley Harpole ◽  
Kirsten Kuesel ◽  
Adam Clark
Keyword(s):  
Enzyme Production ◽  
Selection Process ◽  
Evolutionary Game ◽  
Stable States ◽  
Chemostat Model ◽  
The Public ◽  
Snowdrift Game ◽  
The Commons ◽  
Single Complex ◽  
Over Exploitation

Cheating in microbial communities is often regarded as a precursor to a “tragedy of the commons”, ultimately leading to over-exploitation by a few species, and destabilisation of the community. However, this view does not explain the ubiquity of cheaters in nature. Indeed, existing evidence suggests that cheaters are not only evolutionarily and ecologically inevitable, but also play important roles in communities, like promoting cooperative behaviour. We developed a chemostat model with two microbial species and a single, complex nutrient substrate. One of the organisms, an enzyme producer, degrades the substrate, releasing an essential and limiting resource that it can use both to grow and produce more enzymes, but at a cost. The second organism, a cheater, does not produce the enzyme but benefits from the diffused resource produced by the other species, allowing it to benefit from the public good, without contributing to it. We investigated evolutionarily stable states of coexistence between the two organisms and described how enzyme production rates and resource diffusion influence organism abundances. We found that, in the long-term evolutionary scale, monocultures of the producer drive themselves extinct because selection always favours mutant invaders that invest less in enzyme production. However, the presence of a cheater buffers this runaway selection process, preventing extinction of the producer and allowing coexistence. Resource diffusion rate controls cheater growth, preventing it from outcompeting the producer. These results show that competition from cheaters can force producers to maintain adequate enzyme production to sustain both itself and the cheater. This is known in evolutionary game theory as a “snowdrift game” – a metaphor describing a snow shoveler and a cheater following in their clean tracks. We move further to show that cheating can stabilise communities and possibly be a precursor to cooperation, rather than extinction.

scholarly journals Instability of cooperation in finite populations

2019 ◽  
Author(s):  
Chai Molina ◽  
David J. D. Earn
Keyword(s):  
Finite Population ◽  
Selection Process ◽  
Evolutionarily Stable Strategy ◽  
Evolutionary Game ◽  
Evolution Of Cooperation ◽  
Implicit Assumption ◽  
Stable Strategy ◽  
Infinite Population ◽  
Snowdrift Game ◽  
Evolutionarily Stable

AbstractEvolutionary game theory has been developed primarily under the implicit assumption of an infinite population. We rigorously analyze a standard model for the evolution of cooperation (the multi-player snowdrift game) and show that in many situations in which there is a cooperative evolutionarily stable strategy (ESS) if the population is infinite, there is no cooperative ESS if the population is finite (no matter how large). In these cases, contributing nothing is a globally convergently stable finite-population ESS, implying that apparent evolution of cooperation in such games is an artifact of the infinite population approximation. The key issue is that if the size of groups that play the game exceeds a critical proportion of the population then the infinite-population approximation predicts the wrong evolutionary outcome (in addition, the critical proportion itself depends on the population size). Our results are robust to the underlying selection process.

scholarly journals A Study of Taxi Service Mode Choice Based on Evolutionary Game Theory

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Zhu Bai ◽  
Mingxia Huang ◽  
Shuai Bian ◽  
Huandong Wu
Keyword(s):  
Game Theory ◽  
Evolutionary Game Theory ◽  
Mode Choice ◽  
Evolutionary Game ◽  
Payoff Matrix ◽  
Game Model ◽  
Stable States ◽  
Taxi Service ◽  
Service Mode ◽  
The Impact

The emergence of online car-hailing service provides an innovative approach to vehicle booking but has negatively influenced the taxi industry in China. This paper modeled taxi service mode choice based on evolutionary game theory (EGT). The modes included the dispatching and online car-hailing modes. We constructed an EGT framework, including determining the strategies and the payoff matrix. We introduced different behaviors, including taxi company management, driver operation, and passenger choice. This allowed us to model the impact of these behaviors on the evolving process of service mode choice. The results show that adjustments in taxi company, driver, and passenger behaviors impact the evolutionary path and convergence speed of our evolutionary game model. However, it also reveals that, regardless of adjustments, the stable states in the game model remain unchanged. The conclusion provides a basis for studying taxi system operation and management.

scholarly journals The organization and control of an evolving interdependent population

2015 ◽  
Vol 12 (108) ◽  
pp. 20150044 ◽  
Author(s):  
Dervis C. Vural ◽  
Alexander Isakov ◽  
L. Mahadevan
Keyword(s):  
Evolutionary Game Theory ◽  
Large Scale ◽  
Social Evolution ◽  
Evolutionary Game ◽  
Large Scale Structures ◽  
External Perturbations ◽  
Emergence Of Cooperation ◽  
Scale Structures ◽  
And Control ◽  
Evolutionarily Stable

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.

scholarly journals Sustainable tourism modeling: Pricing decisions and evolutionarily stable strategies for competitive tour operators

2018 ◽  
Vol 25 (5) ◽  
pp. 779-799 ◽  
Author(s):  
Yong He ◽  
Peng He ◽  
Feifei Xu ◽  
Chunming (Victor) Shi
Keyword(s):  
Sustainable Tourism ◽  
Evolutionary Game ◽  
Innovation Strategy ◽  
Cost Advantage ◽  
Evolutionarily Stable Strategies ◽  
Environment Friendly ◽  
Pricing Decisions ◽  
Green Tourism ◽  
The Government ◽  
Evolutionarily Stable

In this article, we investigate two competitive tour operators (TOs) who choose between traditional tourism strategy (strategy T) and green tourism innovation strategy (strategy G). Our article attempts to address the following important issues using evolutionary game models: when would TOs facing environment-friendly tourists adopt the strategy G? How do TOs set product prices under different strategy combinations? How can the government effectively motivate TOs to pursue green tourism? Our research results show that a green tourism innovation pioneer could monopolize the market under certain conditions. Furthermore, when the environmental preference of tourists is sufficiently low, no TOs would adopt the strategy G; when it is moderate, only the TO with cost advantage (stronger TO) would adopt the strategy G; when it is sufficiently high, both TOs would select the strategy G. Our research also demonstrates that the stronger TO implements the strategy G mostly independent of the rival’s decisions, but the opposite is true for the TO with cost disadvantage (weaker TO). We further investigate potential government subsidies that can motivate TOs to carry out green tourism simultaneously. Our results suggest that to be more effective, the government first offer the green subsidy to highly competitive tourism locations and/or more innovative TOs.

British Invasion

2021 ◽  
pp. 107-136
Author(s):  
James C. Nicholson
Keyword(s):  
New York ◽  
Second Generation ◽  
Selection Process ◽  
The Other ◽  
Newspaper Coverage ◽  
Woodrow Wilson ◽  
Industrial Town ◽  
The World ◽  
Jockey Club

Chapter Five discusses the origins of the International Race and the British contestants' transatlantic voyage to America. August Belmont II, chairman of the powerful Jockey Club in New York, convinced Benjamin Irish, the farmer and caterer of relatively modest means who owned Epsom Derby winner Papyrus, to agree to a match race against a to-be-determined American horse. Kentucky Derby champion Zev was the likeliest choice. Admiral Cary T. Grayson, friend and physician to former president Woodrow Wilson, owned the other leading American candidate, My Own. But Hildreth and Sinclair manipulated the selection process. Newspaper coverage of the procedural gamesmanship helped to hype the event. Sportswriters' profiles of the men associated with the English horse -- including jockey Steve Donoghue, who had risen from a rough industrial town to become the most famous rider in the world, and a modest second-generation Newmarket trainer named Basil Jarvis -- spread the ballyhoo nationwide.

Critical Issues of TSV and 3D IC Integration

2010 ◽  
Vol 7 (1) ◽  
pp. 35-43 ◽  
Author(s):  
John H. Lau
Keyword(s):  
System On Chip ◽  
The Other ◽  
Single Chip ◽  
3D Ic ◽  
Moore’S Law ◽  
Moore's Law ◽  
Other Hand ◽  
Critical Issues ◽  
Research Problems ◽  
On Chip

Moore's law has been the most powerful driver for the development of the microelectronic industry. This law is grounded in lithography scaling and integration (in 2D) of all functions on a single chip, perhaps through system-on-chip (SoC). On the other hand, the integration of all these functions can be achieved through system-in-package (SiP) or, ultimately, 3D IC integration. However, there are many critical issues for 3D IC integration. In this study, some of the critical issues will be discussed and some potential solutions or research problems will be proposed.

scholarly journals Evolutionarily stable investments in recognition systems explain patterns of discrimination failure and success

2020 ◽  
Vol 375 (1802) ◽  
pp. 20190465 ◽  
Author(s):  
Michael J. Sheehan ◽  
H. Kern Reeve
Keyword(s):  
Signal Detection Theory ◽  
Social Insect ◽  
Experimental Tests ◽  
Theory Model ◽  
The Other ◽  
Theme Issue ◽  
Brood Parasites ◽  
Recognition Systems ◽  
Evolving Models ◽  
Evolutionarily Stable

Many animals are able to perform recognition feats that astound us—such as a rodent recognizing kin it has never met. Yet in other contexts, animals appear clueless as when reed warblers rear cuckoo chicks that bear no resemblance to their own species. Failures of recognition when it would seem adaptive have been especially puzzling. Here, we present a simple tug-of-war game theory model examining how individuals should optimally invest in affecting the accuracy of discrimination between desirable and undesirable recipients. In the game, discriminating individuals (operators) and desirable and undesirable recipients (targets and mimics, respectively) can all invest effort into their own preferred outcome. We demonstrate that stable inaccurate recognition will arise when undesirable recipients have large fitness gains from inaccurate recognition relative to the pay-offs that the other two parties receive from accurate recognition. The probability of accurate recognition is often determined by just the relative pay-offs to the desirable and undesirable recipients, rather than to the discriminator. Our results provide a new lens on long-standing puzzles including a lack of nepotism in social insect colonies, tolerance of brood parasites and male birds caring for extra-pair young in their nests, which our model suggests should often lack accurate discrimination. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests'.

scholarly journals Evolutionary Game Theory: A Generalization of the ESS Definition

2019 ◽  
Vol 21 (04) ◽  
pp. 1950005
Author(s):  
Elvio Accinelli ◽  
Filipe Martins ◽  
Jorge Oviedo
Keyword(s):  
Game Theory ◽  
Strategic Planning ◽  
Evolutionary Game Theory ◽  
Replicator Dynamics ◽  
Evolutionary Game ◽  
Previous Literature ◽  
Evolutionarily Stable Strategies ◽  
Symmetric Games ◽  
Two Populations ◽  
Evolutionarily Stable

In this paper, we study the concept of Evolutionarily Stable Strategies (ESSs) for symmetric games with [Formula: see text] players. The main properties of these games and strategies are analyzed and several examples are provided. We relate the concept of ESS with previous literature and provide a proof of finiteness of ESS in the context of symmetric games with [Formula: see text] players. We show that unlike the case of [Formula: see text], when there are more than two populations an ESS does not have a uniform invasion barrier, or equivalently, it is not equivalent to the strategy performing better against all strategies in a neighborhood. We also construct the extended replicator dynamics for these games and we study an application to a model of strategic planning of investment.

Choosing a Scanning Electron Microscope

1998 ◽  
Vol 4 (S2) ◽  
pp. 896-897
Author(s):  
W. A. Lambe ◽  
P.M. Brady
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Selection Process ◽  
The Other ◽  
Hard Data ◽  
Methodical Approach ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
First Time ◽  
Scanning Electron

The variety of instrumentation available to the researcher today can be overwhelming and confusing. Scanning Electron Microscopes (“SEM's) are no exception, and choosing one can often serve as an exercise in dealing with complexity. First time purchasers are most at risk, being subject to a barrage of information that attempts to sway the purchaser in one direction or the other. As a result, one can sometimes be drawn to the details of the latest “high end” performance parameter, while overlooking the basics. At its worst, the selection process can degrade to one of vague guesswork with little hard data to serve as a compass.By applying a methodical approach to define your individual requirements, carefully designed tests of actual instruments, and discussions with your collaborators, potential and experienced users, one can begin to ensure a successful selection process.

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