arXiv subjects

Xiaodong Huang

Publications and source records attributed to Xiaodong Huang.

16 recordsLinked to original sources

arXiv2026

Decoupling Error Attribution in Cloud-Native Graph-RAG: A Data Integrity Diagnostic Framework

Graph-RAG systems often assume pristine data quality, overlooking the severe impact of perturbations in cloud-native databases. This paper proposes a three-layer decoupled diagnostic framework to orthogonally attribute system errors to reasoning loss, Knowledge Graph (KG) defects, and Cypher generation errors. Evaluated on a spatio-temporal ecological KG of the Southeastern Tibet region with eight defect types, results reveal that data integrity, rather than algorithmic reasoning, is the dominant performance bottleneck, with structural defects degrading system accuracy from 0.93 to 0.39. Crucially, we observe a masking-like phenomenon termed the Parametric Knowledge Masking Effect (PKME), suggesting LLMs compensate for broken retrieval paths using internal memory. This shrinks apparent query generation errors by over 70 percent, obscuring actual storage deterioration and increasing the risk of false negatives for automated monitoring. This work provides a quantitative foundation for auditing and optimizing data integrity in cloud-based information fusion systems.

cs.IR↗

arXiv2024

Fire in SRRN: Next-Gen 3D Temperature Field Reconstruction Technology

In aerospace and energy engineering, accurate 3D combustion field temperature measurement is critical. The resolution of traditional methods based on algebraic iteration is limited by the initial voxel division. This study introduces a novel method for reconstructing three-dimensional temperature fields using the Spatial Radiation Representation Network (SRRN). This method utilizes the flame thermal radiation characteristics and differentiable rendering in graphics, and combines it with a multi-layer perceptron to achieve a functional representation of the flame temperature field. The effectiveness of SRRN is evaluated through simulated temperature field reconstruction experiments with different levels of complexity. The maximum root mean square error is 10.17, which proves the robustness of the algorithm to Gaussian noise and salt-and-pepper noise. We conducted a butane flame temperature field reconstruction experiment, and the maximum relative error between the reconstruction result and the thermocouple measurement value was 4.86%, confirming that the algorithm can achieve accurate reconstruction.

eess.IV↗

arXiv2024

Dark Matter, Quasars, and Superstructures in the Universe (with delta-particle search and spherical universe)

From the observed results of the space distribution of quasars we deduced that neutrino mass is about10^(-1) eV. The fourth stable elementary particle (delta particle) with mass about 10^(0) eV can help explain the energy resource mechanism in quasars, the peaks of Extra-galactic Background Light (EBL) etc. The key is the annihilation of dark matter particles under the super-strong gravitational/electromagnetic fields from supermassive compact celestial bodies (SCCB) such as galactic nuclei, quasars etc. Their origin is at the early era of the universe (EEU) as universe density lo large than lo(cr) and lo/c^(2)=const, and physical singularities (PSs) are produced from inflation-explosion stage. PSs can still hide in SCCB with FTL matter now. The energy scale at lo(cr) is the critical energy E(cr). At E(cr), inner symmetries are degenerated; below E(cr), it can hold at most 4-fold SM. Appendix is the theoretical/phenomenal part related to the mass scales sequence (MSS), inflation-explosion, spherical universe, BSM, new particles etc. The MSS, like a Mendeleev's periodic table, can be used to cosmology.

physics.gen-ph↗

arXiv2022

Observation of emergent Dirac physics at the surfaces of acoustic higher-order topological insulators

Using three-dimensional (3D) sonic crystals as acoustic higher-order topological insulators (HOTIs), we discover two-dimensional (2D) surface states described by spin-1 Dirac equations at the interfaces between the two sonic crystals with distinct topology but the same crystalline symmetry. We find that the Dirac mass can be tuned by the geometry of the two sonic crystals. The sign reversal of the Dirac mass reveals a surface topological transition where the surface states exhibit zero refractive index behavior. When the surface states are gapped, one-dimensional (1D) hinge states emerge due to the topology of the gapped surface states. We confirm experimentally the zero refractive index behavior and the emergent topological hinge states. Our study reveals a multidimensional Wannier orbital control that leads to extraordinary properties of surface states and unveils an interesting topological mechanism for the control of surface waves.

cond-mat.mes-hall↗

arXiv2021

Dual-Polarization Second-Order Photonic Topological Insulators

Second-order photonic topological insulators that host highly localized corner states resilient to defects, are opening new routes towards developing fascinating photonic devices. However, the existing works on second-order photonic topological insulators have mainly focused on either transverse magnetic or transverse electric modes. In this paper, we propose a dual-polarization topological photonic crystal structure for both transverse magnetic and transverse electric modes through topology optimization. Simple tight-binding lattice models are constructed to reveal the topological features of the optimized photonic crystal structure in a transparent way. The optimized dual-polarization second-order photonic topological insulator hosts four groups of corner states with different profiles and eigenfrequencies for both the transverse magnetic and transverse electric modes. Moreover, the robustness of theses corner states against defects is explicitly demonstrated. Our results offer opportunities for developing polarization-independent topological photonic devices.

physics.optics↗

arXiv2021

A fast Petrov-Galerkin spectral method for the multi-dimensional Boltzmann equation using mapped Chebyshev functions

Numerical approximation of the Boltzmann equation presents a challenging problem due to its high-dimensional, nonlinear, and nonlocal collision operator. Among the deterministic methods, the Fourier-Galerkin spectral method stands out for its relative high accuracy and possibility of being accelerated by the fast Fourier transform. However, this method requires a domain truncation which is unphysical since the collision operator is defined in $\mathbb{R}^d$. In this paper, we introduce a Petrov-Galerkin spectral method for the Boltzmann equation in the unbounded domain. The basis functions (both test and trial functions) are carefully chosen mapped Chebyshev functions to obtain desired convergence and conservation properties. Furthermore, thanks to the close relationship of the Chebyshev functions and the Fourier cosine series, we are able to construct a fast algorithm with the help of the non-uniform fast Fourier transform (NUFFT). We demonstrate the superior accuracy of the proposed method in comparison to the Fourier spectral method through a series of 2D and 3D examples.

math.NA↗

arXiv2020

SEMDOT: Smooth-Edged Material Distribution for Optimizing Topology Algorithm

Element-based topology optimization algorithms capable of generating smooth boundaries have drawn serious attention given the significance of accurate boundary information in engineering applications. The basic framework of a new element-based continuum algorithm is proposed in this paper. This algorithm is based on a smooth-edged material distribution strategy that uses solid/void grid points assigned to each element. Named Smooth-Edged Material Distribution for Optimizing Topology (SEMDOT), the algorithm uses elemental volume fractions which depend on the densities of grid points in the Finite Element Analysis (FEA) model rather than elemental densities. Several numerical examples are studied to demonstrate the application and effectiveness of SEMDOT. In these examples, SEMDOT proved to be capable of obtaining optimized topologies with smooth and clear boundaries showing better or comparable performance compared to other topology optimization methods. Through these examples, first, the advantages of using the Heaviside smooth function are discussed in comparison to the Heaviside step function. Then, the benefits of introducing multiple filtering steps in this algorithm are shown. Finally, comparisons are conducted to exhibit the differences between SEMDOT and some well-established element-based algorithms. The validation of the sensitivity analysis method adopted in SEMDOT is conducted using a typical compliant mechanism design case. In addition, this paper provides the Matlab code of SEMDOT for educational and academic purposes.

cs.CE↗

arXiv2020

On smooth or 0/1 designs of the fixed-mesh element-based topology optimization

The traditional element-based topology optimization based on material penalization typically aims at a 0/1 design. Our numerical experiments reveal that the compliance of a smooth design is overestimated when material properties of boundary intermediate elements under the fixed-mesh finite element analysis are interpolated with a material penalization model. This paper proposes a floating projection topology optimization (FPTO) method for seeking a smooth design using the ersatz material model or a 0/1 design using a material penalization model. The proposed floating projection constraint combining with the upper and lower bounds heuristically simulates 0/1 constraints of design variables in the original discrete optimization problem. Numerical examples demonstrate the capability of the proposed element-based topology optimization approach in obtaining 0/1 or smooth designs for 2D and 3D compliance minimization problems. The proposed topology optimization approach can be easily implemented under the framework of the fixed-mesh finite element analysis and provides an alternative way to form explicit topologies of structures, especially when the ersatz material model is adopted.

cs.CE↗

arXiv2020

Dark Matter, Mass Scales Sequence, and Superstructure in the Universe (with extension and summary)

We extend mass scale sequence to a mass tree. From mass tree, the evolution of the universe is described by three stages: chaos, inflation and expansion. The first two stages have c mutations and the inflation appears as a step by step fission process of black holes. The dark matter particles with low mass (neutrino and delta particle) are described in a dual SM or two-fold SM with new symmetry and new interaction, and delta-particle is like inert neutrino but has baryon number (L-B conservation). We emphasize how to search for delta-particle, how to research critical energy, critical density, background particles, and spherical universe. Critical density relates to a type of pseudo-balance black holes (or celestial bodies). Suppose the minimum black hole radius equal to proton radius means we live in a spherical universe, which belong to a big universe, mainly characterized by proton.

physics.gen-ph↗

arXiv2020

Multidimensional sound propagation in 3D high-order topological sonic insulator

High-order topological insulators (TIs) develop the conventional bulk-boundary correspondence theory and rise the interest in searching innovative topological materials. To realize a high-order TI with a wide passband of 1D and 2D transportation modes, we design non-trivial and trivial 3D sonic crystals whose combination mimics the Su-Schrieffer-Heeger model. The high-order topological boundary states can be found at the interfaces, including 0D corner state, 1D hinge state, and 2D surface state. The fabricated sample with the bent two-dimensional and one-dimensional acoustic channels exhibits the multidimensional sound propagation in space, and also verifies the transition between the complete band gap, hinge states, and surface states within the bulk band gap. Among them, the bandwidth of the single-mode hinge state achieves a large relative bandwidth 9.1%, in which sound transports one-dimensionally without significant leak into the surfaces or the bulk. The high-order topological states in the study pave the way for multidimensional sound manipulation in space.

physics.app-ph↗

arXiv2020

Inverse design of higher-order photonic topological insulators

Topological photonics revolutionizes some of the traditional approaches to light propagation and manipulation, and it provides unprecedented means for developing novel photonic devices. Recently discovered higher-order topological phases go beyond the conventional bulk-edge correspondence for photonic crystals and introduce novel opportunities for topological protection. Here, we introduce an intelligent numerical approach for inverse design of higher-order photonic topological insulators with great flexibility for controlling both topological edge and topological corner states. In particular, we consider the second-order photonic topological insulator and design several structures supporting both edge and corner states at different frequencies. By carefully programming these structures, we suggest a novel approach for topological routing of the edge and corner states by changing the operational frequency. Our finding paves the way to integrated topological photonic devices with novel functionalities.

physics.app-ph↗

arXiv2019

One-Bit MUSIC

In this letter, we consider the problem of direction-of-arrival (DOA) estimation with one-bit quantized array measurements. With analysis, it is shown that, under mild conditions the one-bit covariance matrix can be approximated by the sum of a scaled unquantized covariance matrix and a scaled identity matrix. Although the scaling parameters unknown because of the extreme quantization, they do not affect the subspace-based DOA estimators. Specifically, the signal and noise subspaces can be straightforwardly determined through the eigendecomposition of the one-bit covariance matrix, without pre-processing such as unquantized covariance matrix reconstruction. With so-obtained subspaces, the most classical multiple signal classification (MUSIC) technique can be applied to determine the signal DOAs. The resulting method is thus termed as one-bit MUSIC. Thanks to the simplicity of this method, it can be very easily implemented in practical applications, whereas the DOA estimation performance is comparable to the case with unquantized covariance matrix reconstruction, as demonstrated by various simulations.

eess.SP↗

arXiv2016

Dark Matter Particles with Low Mass (and FTL)

From the observed results, we deduced that the mass of the neutrino is about 10^(-1) eV and the mass of the fourth stable elementary particle (delta) is about 10^(0) eV. While neutrino is related to electro-weak field, the fourth stable elementary particle delta is related to gravitation-"strong" field, and some new meta-stable baryons may appear near the TeV region. Therefore, a twofold standard model diagram is proposed, and involves some experiment phenomena: The new meta-stable baryons' decays produce delta particles, which are helpful in explaining the Dijet asymmetry phenomena at LHC of CERN, the different results for the Fermilab's data peak, etc; However, according to the (B-L) invariance, the sterile "neutrino" about the event excess in MiniBooNe is not the fourth neutrino but rather the delta particle; We think that the delta particles are related to the phenomenon about neutrinos FTL, and that anti-neutrinos are faster than neutrinos. FTL is also related to cosmic inflation, singular point disappearance, a finite universe, and abnormal red shift of SN Ia. Besides, the dark matter particles with low mass are helpful in explaining missing solar neutrinos, the CMB angular power spectrum measured by WMAP etc. Some experiments and observations are suggested, especially about the measurement for the speed of gravitational wave c'. c' and c, in physics, represent the limit speeds of moving particles made by different categories of matter with different Lorentz factors. Lorentz transformation is compatible with FTL. This will be helpful to look for new particles.

physics.gen-ph↗

arXiv2016

Large Number, Dark Matter, Dark Energy, and the Superstructures in the Universe (with Extension)

Since there are dark matter particles (neutrino) with mass about 10^(-1)eV in the universe, the superstructures with a scale of 10^(19) solar mass [large number A is about 10^(19)] appeared around the era of the hydrogen recombination. The redshift z distributions of quasars support the existence of superstructures. Since there are superstructures in the universe, it is not necessary for the hypothesis of dark energy. While neutrino is related to electro-weak field, the fourth stable elementary particles (delta particle) with mass about 10^(0)eV to 10^(1)eV is related to gravitation-"strong" field, which suggests p + anti(p)--> n/anti(n) + anti(delta particle)/(delta particle) and that some new meta-stable baryons appeared near the TeV region. Therefore, a twofold standard model diagram is proposed, and related to many experiment phenomena: The new meta-stable baryons' decays produce delta particles, which are helpful to explain the Dijet asymmetry phenomena at LHC of CERN, the different results for the Fermilab's data peak, etc; However, according to the (B-L) invariance, the sterile "neutrino" from "the event excess in MiniBooNe" can not be the fourth neutrino but rather the delta particle; We think that the delta particles are related to the phenomenon about neutrinos FTL, and that anti-neutrinos are faster than neutrinos. FTL is also related to the cosmic inflation, singular point disappearance, and abnormal red shift of SN Ia. Some experiments and observations are suggested. In the Extension section, we clarify "mass tree", our finite universe, cosmic dual expansions, dual SM etc. And the LHC can look for new particles with decay products graviton/delta particle and new interaction indeed.

astro-ph↗

arXiv2011

Universal driving structure of self-sustained oscillatory complex networks

Recently, self-sustained oscillations in complex networks consisting of nonoscillatory nodes (network oscillators) have attracted great interest in diverse natural and social fields. Due to complexity of network behaviors, little is known so far about the basic structures and fundamental rules underlying the oscillations, not to mention the principles of how to control it. In this article we propose a common design principle for oscillations; predict novel and universal Branched Circle (BC) structures of oscillatory networks based on this principle; and suggest an operable Complexity Reduction Method to reveal the BC structures. These ideas are applied to excitable cell networks (including neural cell networks), and genomic regulatory networks. Universal BC structures are identified clearly in these two considerably different systems. These BC structures reveal for the first time both oscillation sources and wave propagation pathways of complex networks, and guide us to control the oscillations with surprisingly high efficiency.

nlin.AO↗

arXiv2010

Structure and control of self-sustained target waves in excitable small-world networks

Small-world networks describe many important practical systems among which neural networks consisting of excitable nodes are the most typical ones. In this paper we study self-sustained oscillations of target waves in excitable small-world networks. A novel dominant phase-advanced driving (DPAD) method, which is generally applicable for analyzing all oscillatory complex networks consisting of nonoscillatory nodes, is proposed to reveal the self-organized structures supporting this type of oscillations. The DPAD method explicitly explores the oscillation sources and wave propagation paths of the systems, which are otherwise deeply hidden in the complicated patterns of randomly distributed target groups. Based on the understanding of the self-organized structure, the oscillatory patterns can be controlled with extremely high efficiency.

nlin.AO↗