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Finding Regions of Heterogeneity in Decision-Making via Expected Conditional Covariance

Neural Information Processing Systems

Individuals often make di ff erent decisions when faced with the same context, due to personal preferences and background. For instance, judges may vary in their leniency towards certain drug-related o ff enses, and doctors may vary in their preference for how to start treatment for certain types of patients.



Finding Regions of Heterogeneity in Decision-Making via Expected Conditional Covariance

Neural Information Processing Systems

Individuals often make di ff erent decisions when faced with the same context, due to personal preferences and background. For instance, judges may vary in their leniency towards certain drug-related o ff enses, and doctors may vary in their preference for how to start treatment for certain types of patients.


A New Parallel Cooperative Landscape Smoothing Algorithm and Its Applications on TSP and UBQP

Wang, Wei, Shi, Jialong, Sun, Jianyong, Liefooghe, Arnaud, Zhang, Qingfu

arXiv.org Artificial Intelligence

Combinatorial optimization problem (COP) is di ffi cult to solve because of the massive number of local optimal solutions in his solution space. V arious methods have been put forward to smooth the solution space of COPs, including homotopic convex (HC) transformation for the traveling salesman problem (TSP). This paper extends the HC transformation approach to unconstrained binary quadratic programming (UBQP) by proposing a method to construct a unimodal toy UBQP of any size. We theoretically prove the unimodality of the constructed toy UBQP . After that, we apply this unimodal toy UBQP to smooth the original UBQP by using the HC transformation framework and empirically verify the smoothing e ff ects. Subsequently, we introduce an iterative algorithmic framework incorporating HC transformation, referred as landscape smoothing iterated local search (LSILS). Our experimental analyses, conducted on various UBQP instances show the e ffectiveness of LSILS. Furthermore, this paper proposes a parallel cooperative variant of LSILS, denoted as PC-LSILS and apply it to both the UBQP and the TSP . Our experimental findings highlight that PC-LSILS improves the smoothing performance of the HC transformation, and further improves the overall performance of the algorithm. Introduction COPs are a class of problems mainly to find an optimal combination to maximize or minimize some performance metrics with limited resources or subject to some constraints. COPs are typically categorized as NP-hard, for which classical optimization methods struggle to find the optimal solution within a reasonable amount of time and become less applicable. Consequently, researchers usually use heuristics or metaheuristics to find near-optimal solutions within a reasonable amount of time. One of the key challenges associated with solving COPs is the presence of numerous local optima in the solution space, primarily attributable to the rugged and irregular nature of their fitness landscapes. It can be hypothesized that smoothing the landscapes of COPs could significantly facilitate the attainment of the global optima.


Generative Inversion for Property-Targeted Materials Design: Application to Shape Memory Alloys

Li, Cheng, Danga, Pengfei, Xiana, Yuehui, Zhou, Yumei, Shi, Bofeng, Ding, Xiangdong, Suna, Jun, Xue, Dezhen

arXiv.org Artificial Intelligence

The design of shape memory alloys (SMAs) with high transformation temperatures and large mechanical work output remains a longstanding challenge in functional materials engineering. Here, we introduce a data-driven framework based on generative adversarial network (GAN) inversion for the inverse design of high-performance SMAs. By coupling a pretrained GAN with a property prediction model, we perform gradient-based latent space optimization to directly generate candidate alloy compositions and processing parameters that satisfy user-defined property targets. The framework is experimentally validated through the synthesis and characterization of five NiTi-based SMAs. Among them, the Ni$_{49.8}$Ti$_{26.4}$Hf$_{18.6}$Zr$_{5.2}$ alloy achieves a high transformation temperature of 404 $^\circ$C, a large mechanical work output of 9.9 J/cm$^3$, a transformation enthalpy of 43 J/g , and a thermal hysteresis of 29 °C, outperforming existing NiTi alloys. The enhanced performance is attributed to a pronounced transformation volume change and a finely dispersed of Ti$_2$Ni-type precipitates, enabled by sluggish Zr and Hf diffusion, and semi-coherent interfaces with localized strain fields. This study demonstrates that GAN inversion offers an efficient and generalizable route for the property-targeted discovery of complex alloys.


Who Attacks, and Why? Using LLMs to Identify Negative Campaigning in 18M Tweets across 19 Countries

Hartman, Victor, Törnberg, Petter

arXiv.org Artificial Intelligence

Negative campaigning is a central feature of political competition, yet empirical research has been limited by the high cost and limited scalability of existing classification methods. This study makes two key contributions. First, it introduces zero-shot Large Language Models (LLMs) as a novel approach for cross-lingual classification of negative campaigning. Using benchmark datasets in ten languages, we demonstrate that LLMs achieve performance on par with native-speaking human coders and outperform conventional supervised machine learning approaches. Second, we leverage this novel method to conduct the largest cross-national study of negative campaigning to date, analyzing 18 million tweets posted by parliamentarians in 19 European countries between 2017 and 2022. The results reveal consistent cross-national patterns: governing parties are less likely to use negative messaging, while ideologically extreme and populist parties -- particularly those on the radical right -- engage in significantly higher levels of negativity. These findings advance our understanding of how party-level characteristics shape strategic communication in multiparty systems. More broadly, the study demonstrates the potential of LLMs to enable scalable, transparent, and replicable research in political communication across linguistic and cultural contexts.


Self Balancing Neural Network: A Novel Method to Estimate Average Treatment Effect

Abdisa, Atomsa Gemechu, Zhou, Yingchun, Qiu, Yuqi

arXiv.org Machine Learning

In observational studies, confounding variables affect both treatment and outcome. Moreover, instrumental variables also influence the treatment assignment mechanism. This situation sets the study apart from a standard randomized controlled trial, where the treatment assignment is random. Due to this situation, the estimated average treatment effect becomes biased. To address this issue, a standard approach is to incorporate the estimated propensity score when estimating the average treatment effect. However, these methods incur the risk of misspecification in propensity score models. To solve this issue, a novel method called the "Self balancing neural network" (Sbnet), which lets the model itself obtain its pseudo propensity score from the balancing net, is proposed in this study. The proposed method estimates the average treatment effect by using the balancing net as a key part of the feedforward neural network. This formulation resolves the estimation of the average treatment effect in one step. Moreover, the multi-pseudo propensity score framework, which is estimated from the diversified balancing net and used for the estimation of the average treatment effect, is presented. Finally, the proposed methods are compared with state-of-the-art methods on three simulation setups and real-world datasets. It has been shown that the proposed self-balancing neural network shows better performance than state-of-the-art methods.


Robots and Children that Learn Together : Improving Knowledge Retention by Teaching Peer-Like Interactive Robots

Tarakli, Imene, Vinanzi, Samuele, Moore, Richard, Di Nuovo, Alessandro

arXiv.org Artificial Intelligence

Despite growing interest in Learning-by-Teaching (LbT), few studies have explored how this paradigm can be implemented with autonomous, peer-like social robots in real classrooms. Most prior work has relied on scripted or Wizard-of-Oz behaviors, limiting our understanding of how real-time, interactive learning can be supported by artificial agents. This study addresses this gap by introducing Interactive Reinforcement Learning (RL) as a cognitive model for teachable social robots. We conducted two between-subject experiments with 58 primary school children, who either taught a robot or practiced independently on a tablet while learning French vocabulary (memorization) and grammatical rules (inference). The robot, powered by Interactive RL, learned from the child's evaluative feedback. Children in the LbT condition achieved significantly higher retention gains compared to those in the self-practice condition, especially on the grammar task. Learners with lower prior knowledge benefited most from teaching the robot. Behavioural metrics revealed that children adapted their teaching strategies over time and engaged more deeply during inference tasks. This work makes two contributions: (1) it introduces Interactive RL as a pedagogically effective and scalable model for peer-robot learning, and (2) it demonstrates, for the first time, the feasibility of deploying multiple autonomous robots simultaneously in real classrooms. These findings extend theoretical understanding of LbT by showing that social robots can function not only as passive tutees but as adaptive partners that enhance meta-cognitive engagement and long-term learning outcomes.