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One Step Beyond: Feedthrough & Placement-Aware Rectilinear Floorplanner
Xu, Zhexuan, Wang, Jie, Xu, Siyuan, Geng, Zijie, Yuan, Mingxuan, Wu, Feng
Floorplanning determines the shapes and locations of modules on a chip canvas and plays a critical role in optimizing the chip's Power, Performance, and Area (PPA) metrics. However, existing floorplanning approaches often fail to integrate with subsequent physical design stages, leading to suboptimal in-module component placement and excessive inter-module feedthrough. To tackle this challenge, we propose Flora, a three-stage feedthrough and placement aware rectilinear floorplanner. In the first stage, Flora employs wiremask and position mask techniques to achieve coarse-grained optimization of HPWL and feedthrough. In the second stage, under the constraint of a fixed outline, Flora achieves a zero-whitespace layout by locally resizing module shapes, thereby performing fine-grained optimization of feedthrough and improving component placement. In the third stage, Flora utilizes a fast tree search-based method to efficiently place components-including macros and standard cells-within each module, subsequently adjusting module boundaries based on the placement results to enable cross-stage optimization. Experimental results show that Flora outperforms recent state-of-the-art floorplanning approaches, achieving an average reduction of 6% in HPWL, 5.16% in FTpin, 29.15% in FTmod, and a 14% improvement in component placement performance.
Geometry-Aware Active Learning of Pattern Rankings via Choquet-Based Aggregation
Opran, Tudor Matei, Loudni, Samir
We address the pattern explosion problem in pattern mining by proposing an interactive learning framework that combines nonlinear utility aggregation with geometry-aware query selection. Our method models user preferences through a Choquet integral over multiple interestingness measures and exploits the geometric structure of the version space to guide the selection of informative comparisons. A branch-and-bound strategy with tight distance bounds enables efficient identification of queries near the decision boundary. Experiments on UCI datasets show that our approach outperforms existing methods such as ChoquetRank, achieving better ranking accuracy with fewer user interactions.
Digital Twin-Assisted Explainable AI for Robust Beam Prediction in mmWave MIMO Systems
Khan, Nasir, Abdallah, Asmaa, Celik, Abdulkadir, Eltawil, Ahmed M., Coleri, Sinem
In line with the AI-native 6G vision, explainability and robustness are crucial for building trust and ensuring reliable performance in millimeter-wave (mmWave) systems. Efficient beam alignment is essential for initial access, but deep learning (DL) solutions face challenges, including high data collection overhead, hardware constraints, lack of explainability, and susceptibility to adversarial attacks. This paper proposes a robust and explainable DL-based beam alignment engine (BAE) for mmWave multiple-input multiple output (MIMO) systems. The BAE uses received signal strength indicator (RSSI) measurements from wide beams to predict the best narrow beam, reducing the overhead of exhaustive beam sweeping. To overcome the challenge of real-world data collection, this work leverages a site-specific digital twin (DT) to generate synthetic channel data closely resembling real-world environments. A model refinement via transfer learning is proposed to fine-tune the pre-trained model residing in the DT with minimal real-world data, effectively bridging mismatches between the digital replica and real-world environments. To reduce beam training overhead and enhance transparency, the framework uses deep Shapley additive explanations (SHAP) to rank input features by importance, prioritizing key spatial directions and minimizing beam sweeping. It also incorporates the Deep k-nearest neighbors (DkNN) algorithm, providing a credibility metric for detecting out-of-distribution inputs and ensuring robust, transparent decision-making. Experimental results show that the proposed framework reduces real-world data needs by 70%, beam training overhead by 62%, and improves outlier detection robustness by up to 8.5x, achieving near-optimal spectral efficiency and transparent decision making compared to traditional softmax based DL models.
Informed Hybrid Zonotope-based Motion Planning Algorithm
Xie, Peng, Betz, Johannes, Alanwar, Amr
-- Optimal path planning in nonconvex free spaces is notoriously challenging, as formulating such problems as mixed-integer linear programs (MILPs) is NP -hard. We propose HZ-MP, an informed Hybrid Zonotope-based Motion Planner, as an alternative approach that decomposes the obstacle-free space and performs low-dimensional face sampling guided by an ellipsotope heuristic, enabling focused exploration along promising transit regions. This structured exploration eliminates the excessive, unreachable sampling that degrades existing informed planners such as AIT* and EIT* in narrow gaps or boxed-goal scenarios. We prove that HZ-MP is probabilistically complete and asymptotically optimal . It converges to near-optimal trajectories in finite time and scales to high-dimensional cluttered scenes.
Context-Aware Behavior Learning with Heuristic Motion Memory for Underwater Manipulation
Buchholz, Markus, Carlucho, Ignacio, Grimaldi, Michele, Koskinopoulou, Maria, Petillot, Yvan R.
Autonomous motion planning is critical for efficient and safe underwater manipulation in dynamic marine environments. Current motion planning methods often fail to effectively utilize prior motion experiences and adapt to real-time uncertainties inherent in underwater settings. In this paper, we introduce an Adaptive Heuristic Motion Planner framework that integrates a Heuristic Motion Space (HMS) with Bayesian Networks to enhance motion planning for autonomous underwater manipulation. Our approach employs the Probabilistic Roadmap (PRM) algorithm within HMS to optimize paths by minimizing a composite cost function that accounts for distance, uncertainty, energy consumption, and execution time. By leveraging HMS, our framework significantly reduces the search space, thereby boosting computational performance and enabling real-time planning capabilities. Bayesian Networks are utilized to dynamically update uncertainty estimates based on real-time sensor data and environmental conditions, thereby refining the joint probability of path success. Through extensive simulations and real-world test scenarios, we showcase the advantages of our method in terms of enhanced performance and robustness. This probabilistic approach significantly advances the capability of autonomous underwater robots, ensuring optimized motion planning in the face of dynamic marine challenges.
Graph-Structured Data Analysis of Component Failure in Autonomous Cargo Ships Based on Feature Fusion
Zhang, Zizhao, Zhao, Tianxiang, Sun, Yu, Sun, Liping, Kang, Jichuan
To address the challenges posed by cascading reactions caused by component failures in autonomous cargo ships (ACS) and the uncertainties in emergency decision-making, this paper proposes a novel hybrid feature fusion framework for constructing a graph-structured dataset of failure modes. By employing an improved cuckoo search algorithm (HN-CSA), the literature retrieval efficiency is significantly enhanced, achieving improvements of 7.1% and 3.4% compared to the NSGA-II and CSA search algorithms, respectively. A hierarchical feature fusion framework is constructed, using Word2Vec encoding to encode subsystem/component features, BERT-KPCA to process failure modes/reasons, and Sentence-BERT to quantify the semantic association between failure impact and emergency decision-making. The dataset covers 12 systems, 1,262 failure modes, and 6,150 propagation paths. Validation results show that the GATE-GNN model achieves a classification accuracy of 0.735, comparable to existing benchmarks. Additionally, a silhouette coefficient of 0.641 indicates that the features are highly distinguishable. In the label prediction results, the Shore-based Meteorological Service System achieved an F1 score of 0.93, demonstrating high prediction accuracy. This paper not only provides a solid foundation for failure analysis in autonomous cargo ships but also offers reliable support for fault diagnosis, risk assessment, and intelligent decision-making systems. The link to the dataset is https://github.com/wojiufukele/Graph-Structured-about-CSA.
Instance space analysis of the capacitated vehicle routing problem
Gouvรชa, Alessandra M. M. M., Paulos, Nuno, Uchoa, Eduardo, Nascimento, Mariรก C. V.
These features aim to answer the question: "What is the general shape of the problem and how does the arrangement of the nodes influence its optimization difficulty?". The following features are used to analyze the geometry of the problem: G1: Area of the enclosing rectangle [11], [12] G2: Convex hull area [12], [15] G3: Ratio of points on the hull [12], [15] G4: Distance of enclosed points to the convex hull contour [12] G5: Edge lengths of the convex hull 5) Nearest neighborhood (NN) features: This features' category regards relationships between each node and its nearest neighbors, capturing the local search space structure and node connectivity. Unlike MST or geometric features, which focus on overall structure, NN features focus on relationships between a node and its closest nodes. These features aim to answer the question: "How are nodes connected to each other in their immediate neighborhoods, and how do these connections influence the optimization difficulty?". The following features are used to describe the neighborhood of each node: NN1: Distance to 1st NN [11], [15] NN2: Number of strongly connected components [16] NN3: Number of weakly connected components [16] NN4: Size of strongly connected components [16] NN5: Size of weakly connected components [16] NN6: Node input degree in directed kNN graph [16] NN7: Ratio of number of strongly and weakly connected components [16] NN8: Angles between a node and its two nearest neighbor nodes [12] 6) VRP Specific Features: This category of features is composed by values obtained directly from the parameter values of the VRP instances, such as vehicle capacity, customer demands, etc.
Mitigating Goal Misgeneralization via Minimax Regret
Sadek, Karim Abdel, Farrugia-Roberts, Matthew, Anwar, Usman, Erlebach, Hannah, de Witt, Christian Schroeder, Krueger, David, Dennis, Michael
Safe generalization in reinforcement learning requires not only that a learned policy acts capably in new situations, but also that it uses its capabilities towards the pursuit of the designer's intended goal. The latter requirement may fail when a proxy goal incentivizes similar behavior to the intended goal within the training environment, but not in novel deployment environments. This creates the risk that policies will behave as if in pursuit of the proxy goal, rather than the intended goal, in deployment -- a phenomenon known as goal misgeneralization. In this paper, we formalize this problem setting in order to theoretically study the possibility of goal misgeneralization under different training objectives. We show that goal misgeneralization is possible under approximate optimization of the maximum expected value (MEV) objective, but not the minimax expected regret (MMER) objective. We then empirically show that the standard MEV-based training method of domain randomization exhibits goal misgeneralization in procedurally-generated grid-world environments, whereas current regret-based unsupervised environment design (UED) methods are more robust to goal misgeneralization (though they don't find MMER policies in all cases). Our findings suggest that minimax expected regret is a promising approach to mitigating goal misgeneralization.
VLMgineer: Vision Language Models as Robotic Toolsmiths
Gao, George Jiayuan, Li, Tianyu, Shi, Junyao, Li, Yihan, Zhang, Zizhe, Figueroa, Nadia, Jayaraman, Dinesh
Tool design and use reflect the ability to understand and manipulate the physical world through creativity, planning, and foresight. As such, these capabilities are often regarded as measurable indicators of intelligence across biological species. While much of today's research on robotic intelligence focuses on generating better controllers, inventing smarter tools offers a complementary form of physical intelligence: shifting the onus of problem-solving onto the tool's design. Given the vast and impressive common-sense, reasoning, and creative capabilities of today's foundation models, we investigate whether these models can provide useful priors to automatically design and effectively wield such tools? We present VLMgineer, a framework that harnesses the code generation abilities of vision language models (VLMs) together with evolutionary search to iteratively co-design physical tools and the action plans that operate them to perform a task. We evaluate VLMgineer on a diverse new benchmark of everyday manipulation scenarios that demand creative tool design and use. Across this suite, VLMgineer consistently discovers tools and policies that solve tasks more effectively and innovatively, transforming challenging robotics problems into straightforward executions. It also outperforms VLM-generated designs from human specifications and existing human-crafted tools for everyday tasks. To facilitate future research on automated tool invention, we will release our benchmark and code.
Ranking Vectors Clustering: Theory and Applications
Fattahi, Ali, Eshragh, Ali, Aslani, Babak, Rabiee, Meysam
We study the problem of clustering ranking vectors, where each vector represents preferences as an ordered list of distinct integers. Specifically, we focus on the k-centroids ranking vectors clustering problem (KRC), which aims to partition a set of ranking vectors into k clusters and identify the centroid of each cluster. Unlike classical k-means clustering (KMC), KRC constrains both the observations and centroids to be ranking vectors. We establish the NP-hardness of KRC and characterize its feasible set. For the single-cluster case, we derive a closed-form analytical solution for the optimal centroid, which can be computed in linear time. To address the computational challenges of KRC, we develop an efficient approximation algorithm, KRCA, which iteratively refines initial solutions from KMC, referred to as the baseline solution. Additionally, we introduce a branch-and-bound (BnB) algorithm for efficient cluster reconstruction within KRCA, leveraging a decision tree framework to reduce computational time while incorporating a controlling parameter to balance solution quality and efficiency. We establish theoretical error bounds for KRCA and BnB. Through extensive numerical experiments on synthetic and real-world datasets, we demonstrate that KRCA consistently outperforms baseline solutions, delivering significant improvements in solution quality with fast computational times. This work highlights the practical significance of KRC for personalization and large-scale decision making, offering methodological advancements and insights that can be built upon in future studies.