Multiple Games Research Articles

An Enhanced Gradient Algorithm for Computing Generalized Nash Equilibrium Applied to Electricity Market Games

This paper introduces an enhanced algorithm for computing generalized Nash equilibria for multiple player nonlinear games, which degenerates in a gradient algorithm for single player games (i.e., optimization problems) or potential games (i.e., equivalent to minimizing the respective potential function), based on the Rosen gradient algorithm. Analytical examples show that it has similar theoretical guarantees of finding a generalized Nash equilibrium when compared to the relaxation algorithm, while numerical examples show that it is faster. Furthermore, the proposed algorithm is as fast as, but more stable than, the Rosen gradient algorithm, especially when dealing with constraints and non-convex games. The algorithm is applied to an electricity market game representing the current electricity market model in Brazil.

Combined effect of incentives and coupling in multigames in two-layer networks

Abstract The lack of cooperation can easily result in inequality among members of a society, which provides an increasing gap between individual incomes. To tackle this issue, we introduce an incentive mechanism based on individual strategies and incomes, wherein a portion of the income from defectors is allocated to reward low-income cooperators, aiming to enhance cooperation by improving the equitable distribution of wealth across the entire population. Moreover, previous research has typically employed network structures or game mechanisms characterized by homogeneity. In this study, we present a network framework that more accurately reflects real-world conditions, where agents are engaged in multiple games, including prisoner’s dilemma games in the top-layer and public good games in the down-layer networks. Within this framework, we introduce the concept of ‘external coupling’ which connects agents across different networks as acquaintances, thereby facilitating access to shared datasets. Our results indicate that the combined positive effects of external coupling and incentive mechanism lead to optimal cooperation rates and lower Gini coefficients, demonstrating a negative correlation between cooperation and inequality. From a micro-level perspective, this phenomenon primarily arises from the regular network, whereas suboptimal outcomes are observed within the scale-free network. These observations help to give a deeper insight into the interplay between cooperation and wealth disparity in evolutionary games in large populations.

Transcription factors SlNOR and SlNOR-like1 regulate steroidal glycoalkaloids biosynthesis in tomato fruit.

Steroidal glycoalkaloids (SGAs) are specialized metabolites in Solanaceae that serve as defensive compounds and undergo significant compositional changes during fruit ripening. This study explored the roles of transcription factors SlNOR and SlNOR-like1 in SGAs biosynthesis during tomato fruit development. UPLC-MS/MS revealed dynamic changes in four major SGAs: tomatidine, β-tomatine, α-tomatine, and Esculeoside A. Transgenic studies with knockout and overexpression lines demonstrated that both SlNOR and SlNOR-like1 positively regulated SGAs accumulation. RT-qPCR analysis showed that these transcription factors modulated multiple GAME genes in the SGAs biosynthetic pathway. Through EMSA and DLR assays, we established that SlNOR and SlNOR-like1 directly bound to and activated GAME25 and GAME40 promoters, two key genes involved in tomatidine synthesis and α-tomatine conversion, respectively. These findings reveal a previously unknown regulatory mechanism of SGAs metabolism and suggest potential strategies for optimizing tomato fruit quality through molecular breeding.

Gradient-tracking-based distributed Nesterov accelerated algorithms for multiple cluster games over time-varying unbalanced digraphs

This paper studies the design of accelerated distributed algorithms for seeking the Nash Equilibrium (NE) of multiple cluster games over time-varying unbalanced digraphs, where players in the same cluster cooperatively minimize the summation of the local cost function and do not concern the interest of other clusters. In this game, the players have limited access to others’ decisions, while they can communicate with others over the inter-cluster and intra-cluster topologies. Accelerated distributed algorithms are proposed based on the decision estimation, Nesterov acceleration, and pseudo gradient estimation to seek the NE of multiple cluster games. We prove that the proposed algorithm linearly converges to the NE using the multistep contraction and linear systems of inequalities. Moreover, three variants of the proposed algorithm are also given for dealing with cases where only partial communication topologies are time-varying and gossip-type. Lastly, the effectiveness of proposed algorithms and the acceleration effect are verified by solving the intrusion–interception confrontation problem of Unmanned Vehicle (UV) swarms in simulations.

The Impact of Exercise Load and Intensity on the Performance of China U24 3x3 Women Teams

This study analyzed the exercise load and exercise intensity of the China U24 3x3 women team in multiple games, combined with the performance data of the players in the game, and explored the impact of these factors on exercise performance. The results showed that there was a significant positive correlation between load intensity and average heart rate, and high load intensity usually led to a higher average heart rate. In addition, performance data such as scoring and rebounding were also significantly correlated with load intensity and load volume. Players with higher scores often underwent higher load volume and load intensity in the game. This shows that in high-intensity games, players' physical fitness and performance are closely related, and reasonable monitoring and management of load intensity are crucial to improving player performance and reducing the risk of injury. The study also showed that there were significant differences in load volume and load intensity between the U24 Blue Team and the U24 Red Team in different games, further emphasizing the importance of load management in game strategy and physical training. This study provides empirical evidence for basketball teams to formulate scientific training plans and game strategies, and emphasizes the importance of exercise load and intensity management to improve the overall performance of the team and the individual performance of the players.

Effects Of Bilateral Upper Extremity Exercises Training On Trunk Performance, Posture And Gait In Patients With Subacute Stroke-A Quasi Experimental Study

Background and objective: Stroke is one of the neurological disorders which is caused by disturbance in blood supply to the brain resulting in weakness in contralateral limbs and axial musculature. Stroke is the leading cause of physical impairment where the most prominent motor deficit is paresis of one side of body, which is contralateral to the event. This study was conducted with an aim to assess the effectiveness of bilateral upper extremity training on trunk performance, posture and gait in patients with subacute stroke. Method: 30 subjects with subacute stroke were selected for the study. Subjects were treated for 3 days/week for 12 sessions with 45 minutes of task oriented, strengthening training and PNF technique for bilateral upper extremity along with conventional training. The rehabilitation protocol consists of bilateral functional exercises, activity of daily living goal, exercises in multiple movement games, strengthening exercises for lower limb, controlled sitting training, sit to stand training, weight bearing and balance training Conclusion: Significant improvement in all items of TIS, PASS and DGI were observed after intervention (P< 0.001). The study concluded that bilateral upper extremity training is more effective in improving trunk control, posture and gait in subacute stroke patients.

Playing to Collaborate: Using Cooperative Board Games to Experience and Reflect on Collaboration in Upper Secondary Education

There is a growing interest among researchers in using board games for supporting learning in school contexts. Co-op board games is a relatively new and promising type of games, which seems well-suited for improving students’ collaboration skills. In this paper, we explore how two groups of Danish high school students interact when playing two different co-op games, The Mind and Forbidden Island, and how they reflect upon their shared game experiences. The data collection is based on video observations of group interaction and student interviews, which use stimulated video recall. In this way, we are able not only to describe the students’ perceived outcomes of the gaming activities, but also their in-game practices. Our data analysis is informed by microsociological perspectives (Goffman and Collins), which are used to map the group interaction rituals and social norms of the students’ gaming encounters. Based on the data analysis, we identify two analytical themes, which concern the students’ use of verbal and non-verbal communication practices as well as their socialisation processes. The findings suggest that co-op games may be used as a valuable educational tool for qualifying high school students’ collaboration skills as well as strengthening their group relations. The students especially valued playing The Mind, which they tried playing for multiple game rounds. Based on these findings, we discuss recommendations for the further use and study of co-op board games in educational settings.

Game Difficulty Prediction Based on Facial Cues and Game Performance

Current research on game difficulty prediction mainly uses heuristic functions or physiological signals. The former does not consider user data, while the latter easily causes interference to the user. This paper proposes a difficulty prediction method based on multiple facial cues and game performance. Specifically, we first utilize various computer vision methods to detect players’ facial expressions, gaze directions, and head poses. Then, we build a dataset by combining these three kinds of data and game performance as inputs, with the subjective difficulty ratings as labels. Finally, we compare the performance of several machine learning methods on this dataset using two classification tasks. The experimental results showed that the multilayer perceptron classifier (abbreviated as MLP) achieved the highest performance on these tasks, and its accuracy increased with the increase in input feature dimensions. These results demonstrate the effectiveness of our method. The proposed method could assist in improving game design and user experience.

Iguanodon: A Code-Breaking Game for Improving Visualization Construction Literacy.

In today's data-rich environment, visualization literacy-the ability to understand and communicate information through charts-is increasingly important. However, constructing effective charts can be challenging due to the numerous design choices involved. Off-the-shelf systems and libraries produce charts with carefully selected defaults that users may not be aware of, making it hard to increase their visualization literacy with those systems. In addition, traditional ways of improving visualization literacy, such as textbooks and tutorials, can be burdensome as they require sifting through a plethora of resources. To address this challenge, we designed Iguanodon, an easy-to-use game application that complements the traditional methods of improving visualization construction literacy. In our game application, users interactively choose whether to apply design choices, which we assign to sub-tasks that must be optimized to create an effective chart. The application offers multiple game variations to help users learn how different design choices should be applied to construct effective charts. Furthermore, our approach easily adapts to different visualization design guidelines. We describe the application's design and present the results of a user study with 37 participants. Our findings indicate that our game-based approach supports users in improving their visualization literacy.

Existence of equilibrium in a dynamic supply chain game with vertical coordination, horizontal competition, and complementary goods

We consider supply chain competition and vertical coordination in a linear–quadratic differential game setting. In this setting, supply chains produce complementary goods and each of them includes a single manufacturer and a single retailer who coordinate their decisions through a revenue-sharing contract with a wholesale price and a fixed sales revenue share. We study a multiple leader-follower Stackelberg game where the manufacturers are the leaders and the retailers are the followers. Competition occurs at both levels of the supply chains. Retailers play Nash and compete in price; manufacturers also play Nash but they compete in choosing their production capacities by exploiting the equilibrium price decisions made by the retailers. We show that open-loop Nash equilibria exist when the manufacturers only receive a wholesale price (there are no longer exploiting the equilibrium price decision made by the retailers, however). When the manufacturers receive both a wholesale-price and a share of the retailers’ sales revenues, equilibria generally no longer exist. The non-existence of an equilibrium stems from the fact that the manufacturers’ instant profits are discontinuous functions of their production capacities. This discontinuity leads to a major technical difficulty in that one cannot apply standard optimal control approaches to study the equilibria of the dynamic game. Our results illustrate the possibility that competition between supply chains might not be sustainable when they sell complementary products and rely on a revenue-sharing agreement.

Cooperation dynamics in multi-issue repeated social dilemma games with correlated strategy.

In the real world, individuals are often involved in collaboration on multiple issues, and these issues may interact with each other. Given the complexity of the interaction, we establish a multi-issue repeated game model, in which individuals participate in multiple social dilemma games simultaneously and repeatedly, and strategies in different issue games are correlated and reactive. We explore the cooperation dynamics of strategies in the population from a multiobjective perspective, in which an individual's preference for each issue is described by a weight vector, and heterogeneous preferences of individuals in the population are also considered. Through simulations on two-issue games, we find that compared to the uncorrelated case, the correlated strategy can significantly promote cooperation in both games regardless of which issue players prefer. Under the condition of homogeneous preference, an increase in the payoff weight of a given issue decreases the level of cooperation in that issue, and the optimal condition to sustain cooperation to the maximum extent is when the payoff weights of all issues are equal. Moreover, under the condition of heterogeneous preference, there exists an optimal proportion of players with different preferences under which the cooperation rate can reach its highest level in the population. This work highlights individual trade-offs on different issues when engaging in multiple games simultaneously and further enriches the research of evolutionary games from a multiobjective and correlated strategy perspective.

An observability paradox in linked enforcement

The presence of observation errors limits players' ability to detect deviations, and hence the possibility of efficient cooperation in repeated games. When players interact repeatedly in multiple games with imperfect observation in at least one game, however, we find a novel spillover effect that enhances players' ability to sustain cooperation. This finding suggests the presence of observation error can increase the likelihood of efficient cooperation when players interact in multiple repeated games simultaneously. Our result has important implications for industrial organizations, relational contracts, and international cooperation.

From birth to rebirth: comeback meanings in media stories of Canadian athlete mothers’ sporting journeys

ABSTRACT Sport media is a public pedagogy that impacts sportswomen’s embodied subjectivities by circulating gender ideologies and discourses as forms of truth. In this study we used relativist narrative inquiry to build on sport media research exploring socially constructed motherhood and sport. We interrogated ‘comeback meanings’ in sport media stories of four veteran (i.e. multiple Olympic Games appearances, 32–41 years of age) Canadian athletes’ journeys to the 2020 Olympics as first time mothers. Thematic narrative analysis of 86 stories and accompanying images identified two sets of comeback meanings: second chances and redemption and coming back stronger and wiser. Second chances and redemption comebacks were linked with personal and career agency, good mother ideologies, and sacrifice narratives. ‘Hybrid athlete mother’ identities in stories of second chance redemption comebacks were also constructed as generative role models as part of an athletic rebirth. Coming back stronger and wiser in media stories troubled gendered assumptions about veteran athlete mothers as weak/past their prime through constructing their experience as valued, along with body-performance tensions. Both sets of comeback meanings resist biological and ageist ideologies in media stories of veteran athlete mothers while perpetuating neoliberal ideologies and narratives of exceptionalism. These findings show the pedagogical value of media stories for expanding understanding of nuanced shifting discourses identified in interviews and media studies on athlete mothers. The implications of these findings highlight a need for more research exploring digital media forms to learn more about veteran athlete mothers’ embodied subjectivities and implications for elite sport careers.

Intragroup-to-intergroup game envelopment analysis: Multi-subgroup modeling, dual Nash equilibrium, and dynamic evaluation application

In the competitive decision-making process, the mutual competition caused by limited resources can help participants improve their decision-making effectiveness. When it comes to rational self-interest, the competing individuals and groups play mutual games with each other from a partial perspective. In other words, they focus only on the games among the related individuals or groups, ignoring the competition between their related groups or included individuals. Thus, the obtained game results could exclude parallel dependence and progressive transformation relationships between individuals and groups. To address these issues, this study first proposes the intragroup and intragroup-to-intergroup game envelopment analysis models that consider multiple subgroups as the link between individuals and groups to further realize the dual game. Next, we prove that the proposed models show Nash and dual Nash equilibrium phenomena under the multi-subgroup environment, which shows the dual stability of the optimal results after the multiple mutual game calculations. Furthermore, the optimization algorithm in the multi-subgroup environment is fused with the aforementioned models to make global decisions for the intragroup individuals and intragroup-to-intergroup subgroups in the same schedule. Finally, this study applies the new methods to make a dynamic evaluation analysis of different country's banking competitiveness. The derived results demonstrate the real effectiveness of the proposed methods.

Empirically testing a relationship between cooperation and the prime numbers.

Theoretical models suggest a relationship between cooperation and the prime numbers. In environments where agents play multiple one-shot prisoner's dilemma games per generation, cooperators evolve to fixation more frequently when cooperating on a cyclical schedule with a prime-number period length. This finding parrots classic predator-prey models showing selection for prime-number prey life cycles. Here, I report an empirical test of the former models using previously published data concerning humans playing one-shot public goods games across multiple time points-i.e. an analogue to multiple one-shot prisoner's dilemma games. I find very modest evidence of cyclicality at prime-numbered time intervals, though results indicate rough agreement between theoretical predictions and observed rates of full cooperation across time points. Analyses of individual decisions find increased contributions to the public good at prime-number time points and separate placebo tests indicate a 4-in-1000 chance of spuriously estimating this effect. However, when exploratory analyses exclude low-value prime-numbered time points, the magnitude of the estimated effect decreases and the hypothesis of no effect cannot be rejected, implying that low-value, prime-number time points drive estimates, contrary to theoretical model predictions. These findings cast doubt on the hypothesis of increased cooperation at prime-number time points-at least among humans playing public goods games.

Exploring Common Game Elements in Serious Game Interventions for Health and Obesity Awareness in Children: A Systematic Review

Obesity is a growing health challenge. Serious game interventions can increase awareness of health and obesity, especially among children, and the effectiveness of these interventions depends on specific game elements. This review aimed to identify the most common game elements in serious game interventions for raising awareness about obesity in children. We conducted a literature search in the ACM digital library, IEEE Xplore, and Scopus databases for serious games designed and developed for obesity or health awareness. The extracted game elements are based on a pyramid with three categories: components, mechanics, and dynamics, according to Werbach and Hunter (2012). Each dimension, or category, consisted of various game elements. 1349 articles were identified. We found 27 game elements distributed across the 17 selected studies. The most common game elements were ‘Points,’ ‘Quests,’ ‘Challenges,’ ‘Feedbacks,’ ‘Constraints,’ ‘Progression,’ ‘Avatar,’ ‘Win States,’ ‘Achievement,’ and ‘Rewards.’ Serious game interventions for health promotion in children include multiple game elements that are crucial in designing and developing a game. The inclusion of these game elements depends on the learning outcomes and the purpose of the game.

Differential graphical games of multiagent systems with nonzero leader's control input and external disturbances

AbstractIn this article, we investigate the problem of differential graphical games for multiagent systems (MASs) with external disturbances. In particular, the system considered in this article allows the leader to have an unknown bounded control input, and the communication topology between agents is allowed to be a weakly restricted structure with only containing a directed spanning tree. We propose a novel dynamic sliding mode control strategy to dispose the presence of leader's nonzero control input and external disturbances. Furthermore, a nominal controller based on the worst‐case control strategies of neighbors is designed to provide a distributed solution for differential graphics games of MASs. Finally, our algorithms are applied to solve multiple unmanned surface vessels games. Simulation studies are provided to test the effectiveness of the proposed algorithms.

Physical Activity and Self-Determination towards Exercise among Esports Athletes

BackgroundEsports is competitive video gaming, performed within teams or individually, across multiple genres. Players are required to be sedentary for extended periods and require a high-level of cognitive skills for successful competitive performance. There are conflicting findings within the physical activity research in the esports industry. The aim of this research is to explore self-reported physical activity through accelerometer-assessed physical activity, to gain a better insight into the physical activity behaviours of international e’athletes.MethodParticipants (n = 796) across multiple popular esports games, holding any in-game rank, competing at any level, were recruited. The survey consisted of demographic details, esports experience, the International Physical Activity Questionnaire-Long Form (IPAQ-LF), and Behavioural Regulations towards Exercise Questionnaire (BREQ-3). Within a convenience sample, local intervarsity e’athletes (n = 18) were recruited to wear a wrist-worn accelerometer to measure physical activity for 7-days and then complete the survey. Results from the accelerometers were compared to the survey results to explore physical activity reporting within this population.ResultsWhen comparing IPAQ-LF to accelerometer data, players significantly over-report moderate-to-vigorous physical activity and weekly MET-min− 1 (p = .018, r = .63 and p ≤ .001, r = .92). The BREQ-3 showed that e’athletes categorised as high physical activity displayed significantly higher levels of intrinsic motivation, when compared to players categorised as low and moderate physical activity.ConclusionsE’athletes significantly over report physical activity time when measured through the IPAQ-LF, suggesting previous surveys may overestimate physical activity and further research is needed. Given the exponential growth of the industry and the level of physical inactivity, esports may contribute to global physical inactivity levels.

The strategy dynamics of collective systems: Underlying hindrances beyond two-actor coordination.

Engineering systems, characterized by their high technical complexity and societal intricacies, require a strategic design approach to navigate multifaceted challenges. Understanding the circumstances that affect strategic action in these systems is crucial for managing complex real-world challenges. These challenges go beyond localized coordination issues and encompass intricate dynamics, requiring a deep understanding of the underlying structures impacting strategic behaviors, the interactions between subsystems, and the conflicting needs and expectations of diverse actors. Traditional optimization and game-theoretic approaches to guide individual and collective decisions need adaptation to capture the complexities of these design ecosystems, particularly in the face of increasing numbers of decision-makers and various interconnections between them. This paper presents a framework for studying strategic decision-making processes in collective systems. It tackles the combinatorial complexity and interdependencies inherent in large-scale systems by representing strategic decision-making processes as binary normal-form games, then dissects and reinterprets them in terms of multiple compact games characterized by two real-numbered structural factors and classifies them across four strategy dynamical domains associated with different stability conditions. We provide a mathematical characterization and visual representation of emergent strategy dynamics in games with three or more actors intended to facilitate its implementation by researchers and practitioners and elicit new perspectives on design and management for optimizing systems-of-systems performance. We conclude this paper with a discussion of the opportunities and challenges of adopting this framework within and beyond the context of engineering systems.

Enhancing Psychiatry Resident Bonding and Education using an Escape Room Challenge Activity

Introduction An “escape room” is a game requiring teamwork and problem-solving during which a series of puzzles are solved to escape a locked room. Various escape room activities have been designed for healthcare professionals, including internal medicine residents and nursing students (Anderson et al. Simulation & Gaming 2021; 52(1) 7-17; Rodríguez-Ferrer et al. BMC Med Educ 2022; 22:901; Khanna et al. Cureus 2021; 13 (9) e18314). Escape rooms provide an opportunity for social activity, an important component of resident wellness (Mari et al. BMC Med Educ 2019; 19(1):437). This abstract describes an escape room challenge designed and implemented at our psychiatry residency program quarterly wellness afternoon event, which is an afternoon session dedicated to resident wellness.ObjectivesThe objective of this project was to design and implement an escape room challenge containing multiple game mechanics, including hidden roles, information asymmetry, acting, logical deduction, and spying. This activity was conducted to enhance bonding among residents while reinforcing knowledge in psychiatry.Methods We designed and implemented an escape room for 22 residents. Residents were divided into four teams each tasked with completing a sequence of puzzles to open the final lockbox. Two novel mechanics were added to the activity. Each team had a “clue holder” with clues to help solve all the puzzles. This team member had to conceal their identity because, if any of the other teams identified this person, the original winning team would have to give up the prize to the team that guessed the identity of this person. One member of each team was assigned a “spy” role whose mission was to make it hard for the clue holder to reveal all the clues. An anonymous post-activity survey was completed using Google Forms.Results The script was set in a fictional, abandoned psychiatric emergency room. The first task was a visual puzzle of a historic figure in psychiatry. The second activity involved residents guessing the psychotropic medication being acted out by another resident in the style of charades. The third activity required residents to apply developmental milestones to decode a combination lock. The fourth puzzle involved residents solving riddles by using information gathered from resident profiles on the residency program website.Eleven (50%) residents completed the post-game survey. All residents answered true or very true that they enjoyed the game and that participation helped them better connect with their peers. Eight (73%) residents answered true or very true that they learned something from the activity.ConclusionsAn adapted escape room challenge is a novel wellness activity that enhance resident collegiality, teamwork, and bonding. All residents who completed the post-activity survey indicated that they enjoyed the activity and felt more connected to their peers afterwards.Disclosure of InterestNone Declared