Non-stationarity is a fundamental challenge in multi-agent reinforcement learning (MARL), where agents update their behaviour as they learn. In multi-agent settings, individual agents may have an incomplete view of th...
Non-stationarity is a fundamental challenge in multi-agent reinforcement learning (MARL), where agents update their behaviour as they learn. In multi-agent settings, individual agents may have an incomplete view of the actions of others, which can complicate the learning process. Many theoretical advances in MARL avoid the challenge of non-stationarity by coordinating the policy updates of agents in various ways, including synchronizing times at which agents are allowed to revise their policies. In this paper, we study an asynchronous variant of the decentralized Q-learning algorithm, a recent MARL algorithm for stochastic games. We provide sufficient conditions under which the asynchronous algorithm drives play to equilibrium with high probability. In this generalization, players need not agree on the schedule of policy update times, and may change their policies at their own separately selected times. This work extends the applicability of the decentralized Q-learning algorithm to settings in which parameters are selected in an independent manner, and tames non-stationarity without imposing the coordination assumptions of prior work.
The development of effective closed-loop control algorithms is one of the main challenges in Additive Man-ufacturing (AM). Many parameters of AM processes need continuous monitoring and regulation, with temperature be...
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Uncommon in the South African higher education landscape, online learning came to the fore during the global pandemic. We present an account of the use of Microsoft Teams for hybrid mathematics tutorials in a one-seme...
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This special issue compiles 20 contributions, covering a wide range of latest achievements on dynamical modeling, data-driven algorithms, response predictions, multiple practical applications, and inverse problems. Da...
This special issue compiles 20 contributions, covering a wide range of latest achievements on dynamical modeling, data-driven algorithms, response predictions, multiple practical applications, and inverse problems. Data science plays a crucial role, helping us constructing more accurate dynamical models that capture and reflect the true dynamical changes of a system. At the same time, data science is also a powerful tool for deriving exact solutions of a system. By integrating it with deep learning algorithms, we are able to effectively predict the system responses and successfully apply this in several applications, such as airfoil flutter, arm musculoskeletal system, financial market, and epidemiology. In addition, inverse problems also occupy a pivotal position. Faced with the existing rich data, how to use data to identify the parameters of the model is still a challenging topic worthy of our continued attention and in-depth exploration.
In recent years, the swift progress in Artificial Intelligence (AI) has resulted in to impressive performance across various domains, but the opacity of complex models, often referred to as “black-box” models, has r...
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ISBN:
(数字)9798331517601
ISBN:
(纸本)9798331517618
In recent years, the swift progress in Artificial Intelligence (AI) has resulted in to impressive performance across various domains, but the opacity of complex models, often referred to as “black-box” models, has raised concerns regarding trust and interpretability. This paper addresses these challenges through Explainable Artificial Intelligence (XAI), focusing on Shapley Additive Explanations (SHAP) to interpret a predictive model built on an online retail dataset. The research employs Gradient Boosting Machines (GBM) to predict customer repeat purchases and uses SHAP to provide clear insights into the model’s decision-making process. SHAP effectively identifies key features such as TotalPrice, UnitPrice, and Quantity as the most significant factors driving the model’s predictions. TotalPrice was found to be the most influential feature, demonstrating its strong association with repeat purchases. The analysis reveals that the total price of items purchased is the most significant predictor of repeat purchases, with a SHAP value of 0.45, indicating a strong positive correlation. Additionally, unit price and quantity also play important roles, contributing SHAP values of 0.32 and 0.20, respectively The model achieved an accuracy of 85%, with a precision of 0.78 and a recall of 0.80. These results indicate a robust performance in predicting repeat purchases. Furthermore, the research highlights that consumers from certain countries demonstrate distinct purchasing patterns, influencing overall sales performance. These insights empower retail managers to identify critical variables and adapt marketing strategies accordingly. The analysis not only enhances model transparency but also ensures that the predictions align with business expectations, allowing stakeholders to trust and act on the model’s insights.
Sustainable development requires water resources, and the supply of water is directly linked to economic growth, political and social issues. This article presents the findings of a research study conducted to identif...
Sustainable development requires water resources, and the supply of water is directly linked to economic growth, political and social issues. This article presents the findings of a research study conducted to identify actions, beliefs and perceptions regarding water consumption among students and the possible associations between actions related to water conservation and demographic, socioeconomic and cultural variables. In addition, we aimed at finding any changes in water use habits due to the COVID-19 pandemic. The study was carried out at a university in the city of Joinville (southern Brazil). Non-probabilistic quota sampling was implemented and a total of 246 responses were obtained. Exploratory data analysis was performed by means of descriptive and graphical measures. Classical statistical tests were applied to identify possible associations. The results provided information on the use of water for personal hygiene and cleaning, among others. Based on the understanding of the consumption habits, more targeted awareness-raising actions can be prioritized.
Ground meat may be used to mimic the dielectric properties of human tissue when validating microwave sensors and algorithms. Accurate measurements of the dielectric properties of ground meat are important for this val...
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ISBN:
(数字)9798350399288
ISBN:
(纸本)9798350399295
Ground meat may be used to mimic the dielectric properties of human tissue when validating microwave sensors and algorithms. Accurate measurements of the dielectric properties of ground meat are important for this validation. Based on a pilot study, key considerations for taking reliable measurements of ground beef samples and the effect of hydration on ground beef properties are reported.
Polytomous categorical data, in a nominal or ordinal scale, are frequent in many studies in different areas of knowledge. Depending on experimental design, these data can be obtained with an individual or grouped stru...
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Polytomous categorical data, in a nominal or ordinal scale, are frequent in many studies in different areas of knowledge. Depending on experimental design, these data can be obtained with an individual or grouped structure. In both structures, the multinomial distribution may be suitable to model the response variable and, in general, the generalized logit model is commonly used to relate the covariates’ potential effects on the response variable. After fitting a multi-categorical model, one of the challenges is the definition of an appropriate residual and choosing diagnostic techniques to assess goodness-of-fit, as well as validate inferences based on the model. Since the polytomous variable is multivariate, raw, Pearson, or deviance residuals are vectors and their asymptotic distribution is generally unknown, which leads to potential difficulties in graphical visualization and interpretation. Therefore, the definition of appropriate residuals, as well as the choice of the correct analysis in diagnostic tools is very important, especially for nominal categorical data, where a restriction of methods is observed. This paper proposes the use of randomized quantile residuals associated with individual and grouped nominal data, as well as Euclidean and Mahalanobis distance measures associated with grouped data only, as an alternative method to reduce the dimension of the residuals and to study outliers. To show the effectiveness of the proposed methods, we developed simulation studies with individual and grouped categorical data structures associated with generalized logit models. Parameter estimation was carried out by maximum likelihood and half-normal plots with simulation envelopes were used to assess model performance using residuals and distance metrics. These studies demonstrated a good performance of the quantile residuals and, also, the distance measurements allowed a better interpretation of the graphical techniques. We illustrate the proposed procedures with
The goal of this research is to nd novel optical solutions to the Kundu-Eckhaus equation,which possess crucial role in the eld of nonlinear optics. Collective variable (CV) strategyis adopted to solve governing equati...
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The complexity and heterogeneity of data in many real-world applications pose significant challenges for traditional machine learning and signal processing techniques. For instance, in medicine, effective analysis of ...
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