bluuebunny/crossref_metadata_2025_split huggingface dataset:
Framework for Life Cycle Railway Sustainability Assessment: A Methodological Approach Based on Advanced Methods and Tools
Authors: Giunta Marinella , Leonardi Giovanni 
Published: July 2024

AbstractRailway corridors improvement and development are the most appropriate answer to the need of providing sustainable transportation of people and goods. Indeed, rail is the greener transportation mode since it contributes to the reduction of carbon footprint and energy consumption within the global transportation system. From this perspective, continuing to pursue sustainability objectives, any intervention on railway lines and particularly on track must be focused on the use of materials, components, and techniques able to guarantee the best environmental performances in service life span, also according to Agenda 2030 goal 13 action climate. To this purpose, the decision process at any life stage of construction and maintenance of the track can be supported by advanced methods and tools able to correctly address the right solutions through the quantitative assessment of the related environmental burdens. This study delivers a framework of methods and tools in use for the assessment of the sustainability. An application to a case study is also reported and discussed. Results demonstrated that there is room for the enhancement of environmental behavior of the track during its life cycle by means the suitable selection of materials and techniques for construction and maintenance. Further, the proposed methods have a great potential to support decision-makers.
The Top-Down Solver Verified: Building Confidence in Static Analyzers
Authors: Stade Yannick , Tilscher Sarah , Seidl Helmut 
Published: July 2024

AbstractThe top-down solver (TD) is a local fixpoint algorithm for arbitrary equation systems. It considers the right-hand sides as black boxes and detects dependencies between unknowns on the fly—features that significantly increase both its usability and practical efficiency. At the same time, the recursive evaluation strategy of the TD, combined with the non-local destabilization mechanism, obfuscates the correctness of the computed solution. To strengthen the confidence in tools relying on the TD as their fixpoint engine, we provide a first machine-checked proof of the partial correctness of the TD. Our proof builds on the observation that the TD can be obtained from a considerably simpler recursive fixpoint algorithm, the plain TD, by applying an optimization that neither affects the termination behavior nor the computed result. Accordingly, we break down the proof into a partial correctness proof of the plain TD, which is only then extended to include the optimization. The backbone of our proof is a mutual induction following the solver’s computation trace. We establish sufficient invariants about the solver state to conclude the correctness of its optimization, i.e., the plain TD terminates if and only if the TD terminates, and they return the identical result. The proof is written using Isabelle/HOL and is available in the archive of formal proofs.
Breaking the Mold: Nonlinear Ranking Function Synthesis Without Templates
Authors: Zhu Shaowei , Kincaid Zachary 
Published: July 2024

AbstractThis paper studies the problem of synthesizing (lexicographic) polynomial ranking functions for loops that can be described in polynomial arithmetic over integers and reals. While the analogous ranking function synthesis problem for linear arithmetic is decidable, even checking whether a given function ranks an integer loop is undecidable in the nonlinear setting. We side-step the decidability barrier by working within the theory of linear integer/real rings (LIRR) rather than the standard model of arithmetic. We develop a termination analysis that is guaranteed to succeed if a loop (expressed as a formula) admits a (lexicographic) polynomial ranking function. In contrast to template-based ranking function synthesis in real arithmetic, our completeness result holds for lexicographic ranking functions of unbounded dimension and degree, and effectively subsumes linear lexicographic ranking function synthesis for linear integer loops.
Interactive Theorem Proving Modulo Fuzzing
Authors: Muduli Sujit Kumar , Padulkar Rohan Ravikumar , Roy Subhajit 
Published: July 2024

AbstractInteractive theorem provers (ITPs) exploit the collaboration between humans and computers, enabling proof of complex theorems. Further, ITPs allow extraction of provably correct implementations from proofs. However, often, the extracted code interface with external libraries containing real-life complexities—proprietary library calls, remote/cloud APIs, complex models like ML models, inline assembly, highly non-linear arithmetic, vector instructions etc. We refer to such functions/operations as closed-box components. For such components, the user has to provide appropriate assumed lemmas to model the behavior of these functions. However, we found instances where these assumed lemmas are inconsistent with the actual semantics of these closed-box components. Hence, even correct-by-construction code extracted from an ITP may still behave incorrectly when interfaced with such closed-box components.To this end, we propose StarFuzz, that allows the $$\text {F}^\star $$

F
⋆

interactive theorem prover to provide better end-to-end assurance on the application— even when interfaced with the closed-box components. Under the hood, StarFuzz rides on Sādhak, an SMT solver that combines fuzz testing to allow satisfiability checking over closed-box components. On the $$\text {F}^\star $$

F
⋆

library that includes external implementations in OCaml, StarFuzz discovered four bugs—one bug that revealed an error on the assumed lemmas for a closed-box function, and three bugs in the external implementations of these components.
From Clauses to Klauses
Authors: Reeves Joseph E. , Heule Marijn J. H. , Bryant Randal E. 
Published: July 2024

AbstractSatisfiability (SAT) solvers have been using the same input format for decades: a formula in conjunctive normal form. Cardinality constraints appear frequently in problem descriptions: over $$64\%$$

64
%

of the SAT Competition formulas contain at least one cardinality constraint, while over $$17\%$$

17
%

contain many large cardinality constraints. Allowing general cardinality constraints as input would simplify encodings and enable the solver to handle constraints natively or to encode them using different (and possibly dynamically changing) clausal forms. We modify the modern SAT solver CaDiCaL to handle cardinality constraints natively. Unlike the stronger cardinality reasoning in pseudo-Boolean (PB) or other systems, our incremental approach with cardinality-based propagation requires only moderate changes to a SAT solver, preserves the ability to run important inprocessing techniques, and is easily combined with existing proof-producing and validation tools. Our experimental evaluation on SAT Competition formulas shows our solver configurations with cardinality support consistently outperform other SAT and PB solvers.
Scalable Bit-Blasting with Abstractions
Authors: Niemetz Aina , Preiner Mathias , Zohar Yoni 
Published: July 2024

AbstractThe dominant state-of-the-art approach for solving bit-vector formulas in Satisfiability Modulo Theories (SMT) is bit-blasting, an eager reduction to propositional logic. Bit-blasting is surprisingly efficient in practice but does not generally scale well with increasing bit-widths, especially when bit-vector arithmetic is present. In this paper, we present a novel CEGAR-style abstraction-refinement procedure for the theory of fixed-size bit-vectors that significantly improves the scalability of bit-blasting. We provide lemma schemes for various arithmetic bit-vector operators and an abduction-based framework for synthesizing refinement lemmas. We extended the state-of-the-art SMT solver Bitwuzla with our abstraction-refinement approach and show that it significantly improves solver performance on a variety of benchmark sets, including industrial benchmarks that arise from smart contract verification.
Syntax-Guided Automated Program Repair for Hyperproperties
Authors: Beutner Raven , Hsu Tzu-Han , Bonakdarpour Borzoo , Finkbeiner Bernd 
Published: July 2024

AbstractWe study the problem of automatically repairing infinite-state software programs w.r.t. temporal hyperproperties. As a first step, we present a repair approach for the temporal logic HyperLTL based on symbolic execution, constraint generation, and syntax-guided synthesis of repair expression (SyGuS). To improve the repair quality, we introduce the notation of a transparent repair that aims to find a patch that is as close as possible to the original program. As a practical realization, we develop an iterative repair approach. Here, we search for a sequence of repairs that are closer and closer to the original program’s behavior. We implement our method in a prototype and report on encouraging experimental results using off-the-shelf SyGuS solvers.
Safe Exploration in Reinforcement Learning by Reachability Analysis over Learned Models
Authors: Wang Yuning , Zhu He 
Published: July 2024

AbstractWe introduce VELM, a reinforcement learning (RL) framework grounded in verification principles for safe exploration in unknown environments. VELM ensures that an RL agent systematically explores its environment, adhering to safety properties throughout the learning process. VELM learns environment models as symbolic formulas and conducts formal reachability analysis over the learned models for safety verification. An online shielding layer is then constructed to confine the RL agent’s exploration solely within a state space verified as safe in the learned model, thereby bolstering the overall safety profile of the RL system. Our experimental results demonstrate the efficacy of VELM across diverse RL environments, highlighting its capacity to significantly reduce safety violations in comparison to existing safe learning techniques, all without compromising the RL agent’s reward performance.
Using Four-Valued Signal Temporal Logic for Incremental Verification of Hybrid Systems
Authors: Lercher Florian , Althoff Matthias 
Published: July 2024

AbstractHybrid systems are often safety-critical and at the same time difficult to formally verify due to their mixed discrete and continuous behavior. To address this issue, we propose a novel incremental verification algorithm for hybrid systems based on online monitoring techniques and reachability analysis. To this end, we develop a four-valued semantics for signal temporal logic that allows us to distinguish two types of uncertainty: one arising from set-based evaluation and another one from the incremental nature of our algorithm. Using these semantics to continuously update the verification verdict, our verification algorithm is the first to run alongside the reachability analysis of the system to be verified. This makes it possible to stop the reachability analysis as soon as we obtain a conclusive verdict. We demonstrate the usefulness of our novel approach by several experiments.
What Should Be Observed for Optimal Reward in POMDPs?
Authors: Konsta Alyzia-Maria , Lluch Lafuente Alberto , Matheja Christoph 
Published: July 2024

AbstractPartially observable Markov Decision Processes (POMDPs) are a standard model for agents making decisions in uncertain environments. Most work on POMDPs focuses on synthesizing strategies based on the available capabilities. However, system designers can often control an agent’s observation capabilities, e.g. by placing or selecting sensors. This raises the question of how one should select an agent’s sensors cost-effectively such that it achieves the desired goals. In this paper, we study the noveloptimal observability problem(oop): Given a POMDP$$\mathscr {M}$$M, how should one change$$\mathscr {M}$$M’s observation capabilities within a fixed budget such that its (minimal) expected reward remains below a given threshold? We show that the problem is undecidable in general and decidable when considering positional strategies only. We present two algorithms for a decidable fragment of theoop: one based on optimal strategies of$$\mathscr {M}$$M’s underlying Markov decision process and one based on parameter synthesis with SMT. We report promising results for variants of typical examples from the POMDP literature.
Localized Attractor Computations for Infinite-State Games
Authors: Schmuck Anne-Kathrin , Heim Philippe , Dimitrova Rayna , Nayak Satya Prakash 
Published: July 2024

AbstractInfinite-state games are a commonly used model for the synthesis of reactive systems with unbounded data domains. Symbolic methods for solving such games need to be able to construct intricate arguments to establish the existence of winning strategies. Often, large problem instances require prohibitively complex arguments. Therefore, techniques that identify smaller and simpler sub-problems and exploit the respective results for the given game-solving task are highly desirable.In this paper, we propose the first such technique for infinite-state games. The main idea is to enhance symbolic game-solving with the results of localized attractor computations performed in sub-games. The crux of our approach lies in identifying useful sub-games by computing permissive winning strategy templates in finite abstractions of the infinite-state game. The experimental evaluation of our method demonstrates that it outperforms existing techniques and is applicable to infinite-state games beyond the state of the art.
Regular Reinforcement Learning
Authors: Dohmen Taylor , Perez Mateo , Somenzi Fabio , Trivedi Ashutosh 
Published: July 2024

AbstractIn reinforcement learning, an agent incrementally refines a behavioral policy through a series of episodic interactions with its environment. This process can be characterized as explicit reinforcement learning, as it deals with explicit states and concrete transitions. Building upon the concept of symbolic model checking, we propose a symbolic variant of reinforcement learning, in which sets of states are represented through predicates and transitions are represented by predicate transformers. Drawing inspiration from regular model checking, we choose regular languages over the states as our predicates, and rational transductions as predicate transformations. We refer to this framework as regular reinforcement learning, and study its utility as a symbolic approach to reinforcement learning. Theoretically, we establish results around decidability, approximability, and efficient learnability in the context of regular reinforcement learning. Towards practical applications, we develop a deep regular reinforcement learning algorithm, enabled by the use of graph neural networks. We showcase the applicability and effectiveness of (deep) regular reinforcement learning through empirical evaluation on a diverse set of case studies.
Understanding the SM gauge group from SMEFT
Authors: Li Hao-Lin , Xu Ling-Xiao 
Published: July 2024

Abstract
We discuss heavy particles that can be used to pin down the faithful Standard Model (SM) gauge group and their patterns in the SM effective field theory (SMEFT). These heavy particles are not invariant under a specific ℤ6 subgroup of SU(3)c × SU(2)L × U(1)Y, which however acts trivially on all the SM particles, hence the faithful SM gauge group remains undetermined. Different realizations of the faithful SM gauge group correspond to different spectra of heavy particles, and they also correspond to distinct sets of line operators with one-form global symmetry acting on them. We show that the heavy particles not invariant under the ℤ6 group cannot appear in tree-level ultraviolet completions of SMEFT, this enforces us to consider one-loop UV completions of SMEFT to identify the ℤ6 non-invariant heavy particles. We demonstrate with examples that correlations between Wilson coefficients provide an efficient way to examine models with ℤ6 non-invariant heavy particles. Finally, we prove that all the scalars that can trigger electroweak symmetry breaking must be invariant under the ℤ6 group, hence they cannot be used to probe the faithful SM gauge group.
Precision electroweak tensions and a dark photon
Authors: Harigaya Keisuke , Petrosky Evan , Pierce Aaron 
Published: July 2024

Abstract
We examine how different assumptions about the hadronic vacuum polarization, the W boson mass, and the forward-backward asymmetry in b-quarks at the Z pole can impact the precision electroweak fit. We study the implications for a kinetically mixed dark photon, addressing the complementarity of precision bounds and direct searches, particularly in the case where the dark photon can decay into the dark sector, and we consider implications for future Large Hadron Collider searches. We comment on cases where the precision effects of the dark photon may not be well-described by the oblique parameters.
Liouville gravity at the end of the world:deformed defects in AdS/BCFT
Authors: Neuenfeld Dominik , Svesko Andrew , Sybesma Watse 
Published: July 2024

Abstract
We study shape deformations of two-dimensional end-of-the-world (ETW) branes, such as those in bottom-up models of two-dimensional holographic boundary conformal field theories (BCFT), and derive an action for the theory of brane deformations in any bulk three-dimensional maximally symmetric spacetime. In the case of a bulk anti-de Sitter (AdS) spacetime, at leading order in the ultraviolet cutoff, the induced theory on the brane controlling its shape is Liouville gravity coupled to quantum matter. We show in certain limits the theory reduces to semi-classical AdS, dS or flat Jackiw-Teitelboim (JT) gravity, thus providing the first doubly-holographic derivation of two-dimensional models of dilaton gravity minimally coupled to a large number of conformal fields. Specializing to the AdS JT gravity limit, we discuss the dual BCFT interpretation and provide evidence that changing the boundary conditions of JT gravity on the brane is equivalent to a deformation of the dual BCFT with the displacement operator. This establishes a doubly-holographic triality between (i) brane deformations in the bulk, (ii) JT gravity in the brane description, and (iii) irrelevant deformations of the CFT boundary. Lastly, in the presence of a non-trivial dilaton profile, we prove that the Ryu-Takayanagi formula for holographic BCFTs receives a contact term whenever the minimal surface ends on the brane.
Constraints from the neutron EDM on subleading effective operators for direct Dark Matter searches
Authors: Drees Manuel , Mehra Rahul 
Published: July 2024

Abstract
Interactions between Dark Matter (DM) and nucleons relevant for direct search experiments can be organised in a model independent manner using a Galiliean invariant, non-relativistic effective field theory (NREFT). Here one expands the interactions in powers of the momentum transfer $$ \overrightarrow{q} $$

q
→

and DM velocity $$ \overrightarrow{v} $$

v
→

. This approach generates many operators. The potentially most important subleading operators are odd under T, and can thus only be present in a theory with CP violating interactions. We consider two such operators, called $$ \mathcal{O} $$
O
10 and $$ \mathcal{O} $$
O
11 in the literature, in simplified models with neutral spin−0 mediators; the couplings are chosen such that the coefficient of the leading spin independent (SI) operator, which survives for $$ \overrightarrow{v} $$

v
→

→ 0, vanishes at tree level. However, it is generically induced at the next order in perturbation theory. We perform a numerical comparison of the number of scattering events between interactions involving the T−odd operators and the corresponding loop induced SI contributions. We find that for “maximal” CP violation the former can dominate over the latter. However, in two of the three models we consider, an electric dipole moment of the neutron (nEDM) is induced at two-loop order. We find that the experimental bound on the nEDM typically leads to undetectably small rates induced by $$ \mathcal{O} $$
O
10. On the other hand, the model leading to a nonvanishing coefficient of $$ \mathcal{O} $$
O
11 does not induce an nEDM.
Renormalization group flows in AdS and the bootstrap program
Authors: Meineri Marco , Penedones Joao , Spirig Taro 
Published: July 2024

Abstract
We study correlation functions of the bulk stress tensor and boundary operators in Quantum Field Theories (QFT) in Anti-de Sitter (AdS) space. In particular, we derive new sum rules from the two-point function of the stress tensor and its three-point function with two boundary operators. In AdS2, this leads to a bootstrap setup that involves the central charge of the UV limit of the bulk QFT and may allow to follow a Renormalization Group (RG) flow non-perturbatively by continuously varying the AdS radius. Along the way, we establish the convergence properties of the newly discovered local block decomposition of the three-point function.
Assessing wire EDM as a novel approach for CFRP drilling: performance and thermal analysis across lay-up configurations
Authors: Bajoria Aman , Alshaer Ahmad , Abdallah Ramy 
Published: July 2024

AbstractConventional drilling of carbon fibre–reinforced plastic (CFRP) presents significant challenges due to the material’s abrasive nature and anisotropic properties, leading to tool wear, delamination, and surface damage. To address these challenges, this study pioneers the use of wire electrical discharge machining (WEDM) to evaluate the drilling performance of thick CFRP lay-up configurations mainly unidirectional and multidirectional, marking the first application of WEDM for CFRP drilling. The study evaluates material removal rate (MRR), delamination factor (DF), and surface damage while employing an analytical solution to estimate surface temperature and heat conduction in the laminates. An eight-full factorial experimental design was employed, involving variations in ignition current (3 A and 5 A) and pulse-off time (4 µs and 8 µs). The findings revealed that the multidirectional lay-up achieved an MRR of 2.85 mm3/min, significantly outperforming the unidirectional lay-up’s MRR of 0.95 mm3/min, representing a 300% increase at 5 A and 4 µs. However, the increase in discharge energy led to surface damage such as delamination, frayed fibres, and irregular circularity, especially evident in the unidirectional lay-up. For delamination, the multidirectional lay-up had the highest top DF of 1.4 at 5 A and 6 µs, while the unidirectional lay-up achieved the peak bottom DF of 1.24 at the same levels. While none of the parameters significantly affected the responses, the current exhibited the highest contribution ratios. Analytical predictions of the thermal distribution indicated a 45-µm delamination length at the laminate surface and depth, aligning closely with experimental predictions of 30–50 µm.