James Madison University
In this paper we develop a deforestation detection pipeline that incorporates optical and Synthetic Aperture Radar (SAR) data. A crucial component of the pipeline is the construction of anomaly maps of the optical data, which is done using the residual space of a discrete Karhunen-Loève (KL) expansion. Anomalies are quantified using a concentration bound on the distribution of the residual components for the nominal state of the forest. This bound does not require prior knowledge on the distribution of the data. This is in contrast to statistical parametric methods that assume knowledge of the data distribution, an impractical assumption that is especially infeasible for high dimensional data such as ours. Once the optical anomaly maps are computed they are combined with SAR data, and the state of the forest is classified by using a Hidden Markov Model (HMM). We test our approach with Sentinel-1 (SAR) and Sentinel-2 (Optical) data on a 92.19km×91.80km92.19\,km \times 91.80\,km region in the Amazon forest. The results show that both the hybrid optical-radar and optical only methods achieve high accuracy that is superior to the recent state-of-the-art hybrid method. Moreover, the hybrid method is significantly more robust in the case of sparse optical data that are common in highly cloudy regions.
Natural environments pose significant challenges for autonomous robot navigation, particularly due to their unstructured and ever-changing nature. Hiking trails, with their dynamic conditions influenced by weather, vegetation, and human traffic, represent one such challenge. This work introduces a novel approach to autonomous hiking trail navigation that balances trail adherence with the flexibility to adapt to off-trail routes when necessary. The solution is a Traversability Analysis module that integrates semantic data from camera images with geometric information from LiDAR to create a comprehensive understanding of the surrounding terrain. A planner uses this traversability map to navigate safely, adhering to trails while allowing off-trail movement when necessary to avoid on-trail hazards or for safe off-trail shortcuts. The method is evaluated through simulation to determine the balance between semantic and geometric information in traversability estimation. These simulations tested various weights to assess their impact on navigation performance across different trail scenarios. Weights were then validated through field tests at the West Virginia University Core Arboretum, demonstrating the method's effectiveness in a real-world environment.
Semi-free ideal rings, or semifirs, were introduced by Paul M. Cohn to study universal localizations in the non-commutative setting. We provide new examples of semifirs consisting of analytic functions in several non-commuting variables. These examples arise canonically in free analysis by completing the free algebra in the topology of ``uniform convergence on operator-space balls'' in the non-commutative universe of tuples of square matrices of any finite size. We show, in particular, that the ring of (uniformly) entire non-commutative (NC) functions in dNd \in \mathbb{N} non-commuting variables, \scrOd\scr{O}_d, is a semifir. Every finitely--generated right (or left) ideal in \scrOd\scr{O}_d is closed, which yields an analytic extension of G. Bergman's nullstellensatz for the free algebra. Any semifir admits a universal skew field of fractions; applying this to \scrOd\scr{O}_d yields the universal skew field of ``NC meromorphic expressions", \scrMd\scr{M} _d. We show that any f\scrMdf \in \scr{M} _d has a well-defined domain and evaluations in a large class of stably-finite topological algebras, including finite CC^*-algebras, extending a result of Cohn for NC rational functions. As an application, we extend the almost sure convergence result of Haagerup and Thorbjörnsen for free polynomials evaluated on tuples of random matrices to the setting of NC meromorphic expressions.
Modeling the evolution of high-dimensional systems from limited snapshot observations at irregular time points poses a significant challenge in quantitative biology and related fields. Traditional approaches often rely on dimensionality reduction techniques, which can oversimplify the dynamics and fail to capture critical transient behaviors in non-equilibrium systems. We present Multi-Marginal Stochastic Flow Matching (MMSFM), a novel extension of simulation-free score and flow matching methods to the multi-marginal setting, enabling the alignment of high-dimensional data measured at non-equidistant time points without reducing dimensionality. The use of measure-valued splines enhances robustness to irregular snapshot timing, and score matching prevents overfitting in high-dimensional spaces. We validate our framework on several synthetic and benchmark datasets, including gene expression data collected at uneven time points and an image progression task, demonstrating the method's versatility.
Linear Programming (LP) is a foundational optimization technique with widespread applications in finance, energy trading, and supply chain logistics. However, traditional Central Processing Unit (CPU)-based LP solvers often struggle to meet the latency and scalability demands of dynamic, high-dimensional industrial environments, creating a significant computational challenge. This project addresses these limitations by accelerating linear programming on AMD Graphics Processing Units (GPUs), leveraging the ROCm open-source platform and PyTorch. The core of this work is the development of a robust, high-performance, open-source implementation of the Primal-Dual Hybrid Gradient (PDHG) algorithm, engineered specifically for general LP problems on AMD hardware. Performance is evaluated against standard LP test sets and established CPU-based solvers, with a particular focus on challenging real- world instances including the Security-Constrained Economic Dispatch (SCED) to guide hyperparameter tuning. Our results show a significant improvement, with up to a 36x speedup on GPU over CPU for large-scale problems, highlighting the advantages of GPU acceleration in solving complex optimization tasks.
This study systematically assesses the mathematical reasoning capabilities of eight leading Large Language Models across three diverse benchmarks including MATH, GSM8K, and MMLU mathematical subsets. The research identifies performance variations, highlights efficiency-accuracy trade-offs, and provides detailed insights into model strengths and weaknesses in arithmetic, algebra, geometry, and formal logic.
Exclusive photoproduction of K+ΛK^+ \Lambda final states off a proton target has been an important component in the search for missing nucleon resonances and our understanding of the production of final states containing strange quarks. Polarization observables have been instrumental in this effort. The current work is an extension of previously published CLAS results on the beam-recoil transferred polarization observables CxC_x and CzC_z. We extend the kinematic range up to invariant mass W=3.33W=3.33~GeV from the previous limit of W=2.5W=2.5~GeV with significantly improved statistical precision in the region of overlap. These data will provide for tighter constraints on the reaction models used to unravel the spectrum of nucleon resonances and their properties by not only improving the statistical precision of the data within the resonance region, but also by constraining tt-channel processes that dominate at higher WW but extend into the resonance region.
Powerful ionized accretion disk winds are often observed during episodic outbursts in Galactic black hole transients. Among those X-ray absorbers, \fexxvi\ doublet structure (Lyα1\alpha_1+Lyα2\alpha_2 with 20\sim 20eV apart) has a unique potential to better probe the underlying physical nature of the wind; i.e. density and kinematics. We demonstrate, based on a physically-motivated magnetic disk wind scenario of a stratified structure in density and velocity, that the doublet line profile can be effectively utilized as a diagnostics to measure wind density and associated velocity dispersion (due to thermal turbulence and/or dynamical shear motion in winds). Our simulated doublet spectra with post-process radiative transfer calculations indicate that the profile can be (1) broad with a single peak for higher velocity dispersion (\gsim5,000\gsim 5,000 km~s1^{-1}), (2) a standard shape with 1:2 canonical flux ratio for moderate dispersion (1,0005,000\sim 1,000-5,000 km~s1^{-1}) or (3) double-peaked with its flux ratio approaching 1:1 for lower velocity dispersion (\lsim1,000\lsim 1,000 km~s1^{-1}) in optically-thin regime, allowing various line shape. Such a diversity in doublet profile is indeed unambiguously seen in recent observations with XRISM/Resolve at microcalorimeter resolution. We show that some implications inferred from the model will help constrain the local wind physics where \fexxvi\ is predominantly produced in a large-scale, stratified wind.
The muLan experiment at the Paul Scherrer Institute will measure the lifetime of the positive muon with a precision of 1 ppm, giving a value for the Fermi coupling constant G_F at the level of 0.5 ppm. Meanwhile, by measuring the observed lifetime of the negative muon in pure hydrogen, the muCap experiment will determine the rate of muon capture, giving the proton's pseudoscalar coupling g_p to 7%. This coupling can be calculated precisely from heavy baryon chiral perturbation theory and therefore permits a test of QCD's chiral symmetry.
The multidimensional nature of spatial data poses a challenge for visualization. In this paper, we introduce Phoenixmap, a simple abstract visualization method to address the issue of visualizing multiple spatial distributions at once. The Phoenixmap approach starts by identifying the enclosed outline of the point collection, then assigns different widths to outline segments according to the segments' corresponding inside regions. Thus, one 2D distribution is represented as an outline with varied thicknesses. Phoenixmap is capable of overlaying multiple outlines and comparing them across categories of objects in a 2D space. We chose heatmap as a benchmark spatial visualization method and conducted user studies to compare performances among Phoenixmap, heatmap, and dot distribution map. Based on the analysis and participant feedback, we demonstrate that Phoenixmap 1) allows users to perceive and compare spatial distribution data efficiently; 2) frees up graphics space with a concise form that can provide visualization design possibilities like overlapping; and 3) provides a good quantitative perceptual estimating capability given the proper legends. Finally, we discuss several possible applications of Phoenixmap and present one visualization of multiple species of birds' active regions in a nature preserve.
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.
In recent years, the Resistive Cylindrical Chamber (RCC) has been introduced as a novel gaseous detector, extending the well-established Resistive Plate Chambers (RPCs) to the case of cylindrical electrode geometry. Preliminary experimental studies have highlighted several promis- ing features of this configuration, motivating the need for further systematic investigations of its operation. In contrast, from the simulation perspective, detailed studies of the RCC have not been performed yet, despite the fact that the cylindrical geometry introduces new degrees of freedom- such as cylinder electrodes radii and voltage polarity- which lead to asymmetric behaviour of the avalanche development according to the polarity of the applied voltage between the electrodes. In this work we present a standalone simulation program specifically designed to model avalanche growth and signal induction in both RPC and RCC geometries. The code implements a stepwise transport model for electron multiplication, includes approximate space-charge effects, and evalu- ates the induced signals on an external electrode. The simulation has been validated against experimental data for planar RPCs and subsequently applied to RCC geometries. The results demonstrate that key observables such as induced charge and efficiency for the planar geometry are well reproduced and highlights the role of electric-field asymmetry in the cylindrical configuration. These findings provide quantitative insights into the impact of detector geometry on avalanche dynamics.
High-fidelity, AI-based simulated classroom systems enable teachers to rehearse effective teaching strategies. However, dialogue-oriented open-ended conversations such as teaching a student about scale factors can be difficult to model. This paper builds a text-based interactive conversational agent to help teachers practice mathematical questioning skills based on the well-known Instructional Quality Assessment. We take a human-centered approach to designing our system, relying on advances in deep learning, uncertainty quantification, and natural language processing while acknowledging the limitations of conversational agents for specific pedagogical needs. Using experts' input directly during the simulation, we demonstrate how conversation success rate and high user satisfaction can be achieved.
Massive rare particles have been searched for in the penetrating cosmic radiation using the MACRO apparatus at the Gran Sasso National Laboratories. Liquid scintillators, streamer tubes and nuclear track detectors have been used to search for magnetic monopoles (MMs). Based on no observation of such signals, stringent flux limits are established for MMs as slow as a few 10^(-5)c. The methods based on the scintillator and on the nuclear track subdetectors were also applied to search for nuclearites. Preliminary results of the searches for charged Q-balls are also presented.
A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498 GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the sin(phiR) moments of ALU are extracted for the kinematic variables of interest in the valence quark region. The understanding of di-hadron production is essential for the interpretation of observables in single hadron production in semi-inclusive DIS, and pioneering measurements of single spin asymmetries in di-hadron production open a new avenue in studies of QCD dynamics.
Entropy-stabilized oxides (ESOs), driven by high configurational entropy, have gained phenomenological research interest due to their potential for tailoring structure property relationships. However, the chemical short range ordering (SRO) and its interplay with local lattice distortion (LD) remain to be explored, although they could diminish the configurational entropy and potentially impact structure property relationships. A combination of experimental and theoretical approaches are employed to investigate the SRO and LD in the prototype ESO, Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O, generally referred to as J14. We demonstrate that the efficiency and accuracy of density functional theory (DFT) relaxed special quasirandom structures (SQS) enhances the analysis of the local structure of J14, unveiling the unique local cationic environments. Importantly, this joint experimental and computational approach sheds light on the understanding of local structure and structure property relationships in J14, demonstrating the necessity for further research into other high entropy and compositionally complex materials.
Inclusive electron scattering cross sections off a hydrogen target at a beam energy of 10.6 GeV have been measured with data collected from the CLAS12 spectrometer at Jefferson Laboratory. These first absolute cross sections from CLAS12 cover a wide kinematic area in invariant mass W of the final state hadrons from the pion threshold up to 2.5 GeV for each bin in virtual photon four-momentum transfer squared Q2Q^2 from 2.55 to 10.4~GeV2^2 owing to the large scattering angle acceptance of the CLAS12 detector. Comparison of the cross sections with the resonant contributions computed from the CLAS results on the nucleon resonance electroexcitation amplitudes has demonstrated a promising opportunity to extend the information on their Q2Q^2 evolution up to 10 GeV2^2. Together these results from CLAS and CLAS12 offer good prospects for probing the nucleon parton distributions at large fractional parton momenta xx for WW < 2.5 GeV, while covering the range of distances where the transition from the strongly coupled to the perturbative regimes is expected.
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