arXiv subjects

Bing Wei

Publications and source records attributed to Bing Wei.

At least 19 recordsLinked to original sources

arXiv2026

Ramsey multiplicity for ordered graphs

Let $\cG_1,\ldots,\cG_k$ be fixed vertex-ordered graphs, each containing at least one edge. The ordered Ramsey number $\oR(\cG_1,\ldots,\cG_k)$ is the least integer $N$ such that every $k$-edge-coloring of the ordered complete graph $\cK_N$ contains an order-preserving copy of $\cG_i$ in color $i$ for some $i\in[k]$. For positive weights $\blambda=(\lambda_1,\ldots,\lambda_k)$, let $\oM_{\blambda}(n;\cG_1,\ldots,\cG_k)$ denote the minimum weighted number of correctly colored, order-preserving copies of the target graphs over all $k$-edge-colorings of $\cK_n$. When $\blambda=\bf{1}$, $\oM_{\bf{1}}(n;\cG_1,\ldots,\cG_k)=\oM(n;\cG_1,\ldots,\cG_k)$ is called the ordered Ramsey multiplicity. In this paper, we first establish the amplification inequality \[ \oM_{\blambda}(n;\cG_1,\ldots,\cG_k) \ge \oM_{\blambda}(t;\cG_1,\ldots,\cG_k) \frac{\binom{n}{\hmin}}{\binom{t}{\hmin}}, \] where $h_i=v(\cG_i),\hmin=\min_{i\in[k]}h_i$, and $n\ge t\ge\oR(\cG_1,\ldots,\cG_k)$. Let $\cS_{r,s}$ be the ordered star whose center has $r-1$ leaves to its left and $s-1$ leaves to its right, and let $\bB_m$ be the family of all ordered perfect matchings on $[2m]$ containing the edge $\{1,2m\}$. We apply the amplification inequality to obtain the multiplicity lower bounds for ordered stars and ordered perfect matchings. We then obtain the upper bound $\oM_{\boldsymbol\lambda} (n;\cS_{r_1,s_1},\cS_{r_2,s_2}) \le \min\{\lambda_1 B_{h_1}(n),\lambda_2 B_{h_2}(n)\}$ by constructions, where $B_{h_i}(n):= \binom{\lfloor n/2\rfloor}{h_i} + \binom{\lceil n/2\rceil}{h_i}$ and $h_i=r_i+s_i-1$ for $i\in [2]$. We also derive a random-coloring upper bound for ordered stars and prove \[\oM(n; \bB_m,\bB_m) \le \binom{n}{2m} \frac{(2m-2)!}{2^{2m-2}(m-1)!}.\] Finally, we establish a regularity-based lifting theorem for ordered colorings.

math.CO↗

arXiv2026

HiFlow: Hierarchical Feedback-Driven Optimization for Constrained Long-Form Text Generation

Large language models perform well in short text generation but still struggle with long text generation, particularly under complex constraints. Such tasks involve multiple tightly coupled objectives, including global structural consistency, local semantic coherence, and constraint feasibility, forming a challenging constrained optimization problem. Existing approaches mainly rely on static planning or offline supervision, limiting effective coordination between global and local objectives during generation. To address these challenges, we propose HiFlow, a hierarchical feedback-driven optimization framework for constrained long text generation. HiFlow formulates generation as a two-level optimization process, consisting of a planning layer for global structure and constraint modeling, and a generation layer for conditioned text generation. By incorporating constraint-aware plan screening and closed-loop feedback at both levels, HiFlow enables joint optimization of planning quality and generation behavior, progressively guiding the model toward high-quality, constraint-satisfying outputs. Experiments on multiple backbones confirm HiFlow's effectiveness over baseline methods.

cs.CL↗

arXiv2026

Design of a 60.8 K superconducting hydride LiMgZr2H12 at ambient pressure via Lithium doping

High-pressure hydrogen-rich compounds have long been regarded as promising room-temperature superconductor candidates; however, their practical applications are limited by their reliance on extreme compression. This study explores hydrogen-rich superconductors that may be stable at ambient pressures. Inspired by recent investigations of the MgZrH2n family, the LiMgZr2H12 structure with a Pmmm symmetry was constructed, and its thermodynamic, mechanical, and dynamical stability were evaluated using first-principles calculations. Electron-phonon coupling (EPC) analysis suggests that LiMgZr2H12 reaches a superconducting critical temperature (Tc) of 60.8 K at ambient pressure. Compared with MgZrH6, Li doping significantly increases the contribution of hydrogen atoms to the electron density of states near the Fermi level (EF) and enhances the EPC constant of the LiMgZr2H12 structure. LiMgZr2H12 exhibits a superconducting figure of merit of 1.56, which is significantly greater than that of MgZrH6, demonstrating its outstanding potential for practical applications. This work guides ambient-pressure design of high-Tc hydrides.

cond-mat.supr-con↗

arXiv2025

Bipartite holes, degree sums and Hamilton cycles

The {\em bipartite-hole-number} of a graph $G$, denoted as $\widetilde\alpha(G)$, is the minimum number $k$ such that there exist integers $a$ and $b$ with $a + b = k+1$ such that for any two disjoint sets $A, B \subseteq V(G)$, there is an edge between $A$ and $B$. McDiarmid and Yolov initiated research on bipartite holes by extending Dirac's classical theorem on minimum degree and Hamiltonian cycles. They showed that a graph on at least three vertices with $\delta(G) \ge \widetilde\alpha(G)$ is Hamiltonian. Later, Dragani\'c, Munh\'a Correia and Sudakov proved that $\delta\ge \widetilde\alpha(G)$ implies that $G$ is pancyclic, unless $G = K_{\frac n2, \frac n2}$. This extended the result of McDiarmid and Yolov and generalized a theorem of Bondy on pancyclicity. In this paper, we show that a $2$-connected graph $G$ is Hamiltonian if $\sigma_2(G) \ge 2 \widetilde\alpha(G) - 1$, and that a connected graph $G$ contains a cycle through all vertices of degree at least $\widetilde\alpha(G)$. Both results extended McDiarmid and Yolov's result. As a step toward proving pancyclicity, we show that if an $n$-vertex graph $G$ satisfies $\sigma_2(G) \ge 2 \widetilde\alpha(G) - 1$, then it either contains a triangle or it is $K_{\frac n2, \frac n2}$. Finally, we discuss the relationship between connectivity and the bipartite hole number.

math.CO↗

arXiv2025

Localization mechanism of the Kalb-Ramond field on brane with codimension-two

The $2$-form Kalb-Ramond (KR) field, together with the metric tensor and dilaton, arises as one of the massless excitation mode of a closed string. Subsequently, this field plays an important role in both string theory and field theory. In this paper, we investigate the localization of the KR field on the brane with codimension-2. A general Kaluza-Klein (KK) decomposition is adopted, wherein the six-dimensional KR field is expanded into one four-dimensional (4D) KR field, two 4D vector fields, and one 4D scalar field. Then, for the case of the extra dimensions $\mathcal{R}_1\times\mathcal{R}_1$, only the 4D scalar field can be localized on the brane. In contrast, for the case of extra dimensions $\mathcal{R}_1\times\mathcal{S}_1$, one 4D vector field and the 4D scalar field can be localized on the brane at the same time. In both cases, the mass of the 4D scalar field remains zero. Next, we examine the localization of the KR field within a specific six-dimensional brane model with extra dimensions $\mathcal{R}_1\times\mathcal{S}_1$. By introducing the background scalar coupling, we show that the 4D KR field, along with the other three 4D fields, can be localized on the brane under the condition of the coupling parameter $t>v^2/12$. Additionally in this case, for both the 4D KR field and the one 4D vector field which acquires its mass from the non-compact extra dimension, the resonant KK modes could exist near the origin of this extra dimension.

hep-th↗

arXiv2025

Multi-Target Federated Backdoor Attack Based on Feature Aggregation

Current federated backdoor attacks focus on collaboratively training backdoor triggers, where multiple compromised clients train their local trigger patches and then merge them into a global trigger during the inference phase. However, these methods require careful design of the shape and position of trigger patches and lack the feature interactions between trigger patches during training, resulting in poor backdoor attack success rates. Moreover, the pixels of the patches remain untruncated, thereby making abrupt areas in backdoor examples easily detectable by the detection algorithm. To this end, we propose a novel benchmark for the federated backdoor attack based on feature aggregation. Specifically, we align the dimensions of triggers with images, delimit the trigger's pixel boundaries, and facilitate feature interaction among local triggers trained by each compromised client. Furthermore, leveraging the intra-class attack strategy, we propose the simultaneous generation of backdoor triggers for all target classes, significantly reducing the overall production time for triggers across all target classes and increasing the risk of the federated model being attacked. Experiments demonstrate that our method can not only bypass the detection of defense methods while patch-based methods fail, but also achieve a zero-shot backdoor attack with a success rate of 77.39%. To the best of our knowledge, our work is the first to implement such a zero-shot attack in federated learning. Finally, we evaluate attack performance by varying the trigger's training factors, including poison location, ratio, pixel bound, and trigger training duration (local epochs and communication rounds).

cs.CR↗

arXiv2024

Independent Bondage Number in Graphs under Girth Constraints

Given a finite, simple graph $G$, the independent bondage number of $G$ is the minimum size of an edge set such that its deletion results in a graph with strictly larger independent domination number than that of $G$. While the bondage number of graphs under girth constraints has been studied, very few results have yet been established for the independent bondage number. In this study, we establish upper bounds on the independent bondage number of planar graphs under given girth constraints, extending results on the bondage number by Fischermann, Rautenbach, and Volkmann and on the structures of planar graphs by Borodin and Ivanova. In particular, we identify additional structures and establish bounds on the independent bondage number for planar graphs with $\delta (G) \geq 2$ and $g(G)\geq 5$, $\delta(G)\geq 3$ and $g(G)\geq 4$, and $\delta (G) \geq 2$ and $g(G)\geq 10$.

math.CO↗

arXiv2024

Research on Information Extraction of LCSTS Dataset Based on an Improved BERTSum-LSTM Model

With the continuous advancement of artificial intelligence, natural language processing technology has become widely utilized in various fields. At the same time, there are many challenges in creating Chinese news summaries. First of all, the semantics of Chinese news is complex, and the amount of information is enormous. Extracting critical information from Chinese news presents a significant challenge. Second, the news summary should be concise and clear, focusing on the main content and avoiding redundancy. In addition, the particularity of the Chinese language, such as polysemy, word segmentation, etc., makes it challenging to generate Chinese news summaries. Based on the above, this paper studies the information extraction method of the LCSTS dataset based on an improved BERTSum-LSTM model. We improve the BERTSum-LSTM model to make it perform better in generating Chinese news summaries. The experimental results show that the proposed method has a good effect on creating news summaries, which is of great importance to the construction of news summaries.

cs.CL↗

arXiv2024

Methodology and Real-World Applications of Dynamic Uncertain Causality Graph for Clinical Diagnosis with Explainability and Invariance

AI-aided clinical diagnosis is desired in medical care. Existing deep learning models lack explainability and mainly focus on image analysis. The recently developed Dynamic Uncertain Causality Graph (DUCG) approach is causality-driven, explainable, and invariant across different application scenarios, without problems of data collection, labeling, fitting, privacy, bias, generalization, high cost and high energy consumption. Through close collaboration between clinical experts and DUCG technicians, 46 DUCG models covering 54 chief complaints were constructed. Over 1,000 diseases can be diagnosed without triage. Before being applied in real-world, the 46 DUCG models were retrospectively verified by third-party hospitals. The verified diagnostic precisions were no less than 95%, in which the diagnostic precision for every disease including uncommon ones was no less than 80%. After verifications, the 46 DUCG models were applied in the real-world in China. Over one million real diagnosis cases have been performed, with only 17 incorrect diagnoses identified. Due to DUCG's transparency, the mistakes causing the incorrect diagnoses were found and corrected. The diagnostic abilities of the clinicians who applied DUCG frequently were improved significantly. Following the introduction to the earlier presented DUCG methodology, the recommendation algorithm for potential medical checks is presented and the key idea of DUCG is extracted.

cs.AI↗

arXiv2024

Statistic Vectorial Complex Ray Model and its Application to Three-Dimension Scattering of a Non-spherical Particle

A Statistic Vectorial Complex Ray Model (SVCRM) is proposed for the scattering of a plane wave by a non-spherical dielectric particle in three dimensions. This method counts the complex amplitudes of all rays arriving in a tiny box in the observation direction. It avoids the two-dimensional interpolation necessary in the Vectorial Complex Ray Model (VCRM) for the calculation of the total field. So, it is more flexible and suitable to deal with the particle of complex shape. The algorithm has been carefully designed for the calculation of the phases due to the optical path, the reflection and the focal lines/points as well as the amplitude variation caused by the reflection, the refraction and the divergence of the wave on the particle surface. This model is then applied, as an example, to simulate the three-dimensional scattering patterns of a pendent drop. The scattering mechanism is analyzed in details and the special attention has been paid to the scattering patterns around the rainbow angles where the caustics occur. The simulated results have been compared to the experimental results for a pendent drop of two typical sizes and shapes. It is shown that the simulated and the experimental results are in good agreement. This method opens a promising potential in the development of optical measurement techniques in fluid mechanics.

physics.optics↗

arXiv2024

Graph Configurations and Independent Bondage Numbers of Planar Graphs

The independent domination number of a finite graph G is the minimum cardinality of an independent dominating set of vertices. The independent bondage number of G is the minimum cardinality of a set of edges whose deletion results in a graph with a larger independent domination number than that of G. In this research, we enhance the existing upper bound on the independent bondage number of a planar graph with a minimum degree of at least three by identifying specific configurations within such planar graphs.

math.CO↗

arXiv2024

On Total Bondage Number of Graphs

In this paper, we explore the concept of total bondage in finite graphs without isolated vertices. A vertex set $D$ is considered a total dominating set if every vertex $v$ in the graph $G$ has a neighbor in $D$. The minimum cardinality of all total dominating sets in $G$ is denoted as $\gamma_t(G)$. A total bondage edge set $B$ is a subset of the edges of $G$ such that the removal of $B$ from $G$ does not create isolated vertices, and the total dominating number of the resulting graph $G-B$ is strictly greater than $\gamma_t(G)$. The total bondage number of $G$, denoted $b_t(G)$, is defined as the minimum cardinality of such total bondage edge sets. Our paper establishes upper bounds on $b_t(G)$ based on the maximum degree of a graph. Notably, for planar graphs with minimum degree $\delta(G) \geq 3$, we prove $b_t(G) \leq \Delta + 8$ or $b_t(G) \leq 10$. Additionally, for a connected planar graph with $\delta(G) \geq 3$ and $g(G) \geq 4$, we show that $b_t(G) \leq \Delta + 3$ if $G$ does not contain an edge with degree sum at most 7. We also improve some upper bounds of the total bondage number for trees, enhance existing lemmas, and find upper bounds for total bondage in specific graph classes.

math.CO↗

arXiv2022

Some exact values on Ramsey numbers related to fans

For two given graphs $F$ and $H$, the Ramsey number $R(F,H)$ is the smallest integer $N$ such that any red-blue edge-coloring of the complete graph $K_N$ contains a red $F$ or a blue $H$. When $F=H$, we simply write $R_2(H)$. For an positive integer $n$, let $K_{1,n}$ be a star with $n+1$ vertices, $F_n$ be a fan with $2n+1$ vertices consisting of $n$ triangles sharing one common vertex, and $nK_3$ be a graph with $3n$ vertices obtained from the disjoint union of $n$ triangles. In 1975, Burr, Erdős and Spencer \cite{B} proved that $R_2(nK_3)=5n$ for $n\ge2$. However, determining the exact value of $R_2(F_n)$ is notoriously difficult. So far, only $R_2(F_2)=9$ has been proved. Notice that both $F_n$ and $nK_3$ contain $n$ triangles and $|V(F_n)|<|V(nK_3)|$ for all $n\ge 2$. Chen, Yu and Zhao (2021) speculated that $R_2(F_n)\le R_2(nK_3)=5n$ for $n$ sufficiently large. In this paper, we first prove that $R(K_{1,n},F_n)=3n-\varepsilon$ for $n\ge1$, where $\varepsilon=0$ if $n$ is odd and $\varepsilon=1$ if $n$ is even. Applying the exact values of $R(K_{1,n},F_n)$, we will confirm $R_2(F_n)\le 5n$ for $n=3$ by showing that $R_2(F_3)=14$.

math.CO↗

arXiv2022

a characterization of the centers of chordal graphs

A graph is $k$-chordal if it does not have an induced cycle with length greater than $k$. We call a graph chordal if it is $3$-chordal. Let $G$ be a graph. The distance between the vertices $x$ and $y$, denoted by $d_{G}(x,y)$, is the length of a shortest path from $x$ to $y$ in $G$. The eccentricity of a vertex $x$ is defined as $ε_{G}(x)= \max\{d_{G}(x,y)|y\in V(G)\}$. The radius of $G$ is defined as $Rad(G)=\min\{ε_{G}(x)|x\in V(G)\}$. The diameter of $G$ is defined as $Diam(G)=\max\{ε_{G}(x)|x\in V(G)\}$. The graph induced by the set of vertices of $G$ with eccentricity equal to the radius is called the center of $G$. In this paper we present new bounds for the diameter of $k$-chordal graphs, and we give a concise characterization of the centers of chordal graphs.

math.CO↗

arXiv2022

Distribution Learning Based on Evolutionary Algorithm Assisted Deep Neural Networks for Imbalanced Image Classification

To address the trade-off problem of quality-diversity for the generated images in imbalanced classification tasks, we research on over-sampling based methods at the feature level instead of the data level and focus on searching the latent feature space for optimal distributions. On this basis, we propose an iMproved Estimation Distribution Algorithm based Latent featUre Distribution Evolution (MEDA_LUDE) algorithm, where a joint learning procedure is programmed to make the latent features both optimized and evolved by the deep neural networks and the evolutionary algorithm, respectively. We explore the effect of the Large-margin Gaussian Mixture (L-GM) loss function on distribution learning and design a specialized fitness function based on the similarities among samples to increase diversity. Extensive experiments on benchmark based imbalanced datasets validate the effectiveness of our proposed algorithm, which can generate images with both quality and diversity. Furthermore, the MEDA_LUDE algorithm is also applied to the industrial field and successfully alleviates the imbalanced issue in fabric defect classification.

cs.CV↗

arXiv2022

Vision Transformer with Convolutions Architecture Search

Transformers exhibit great advantages in handling computer vision tasks. They model image classification tasks by utilizing a multi-head attention mechanism to process a series of patches consisting of split images. However, for complex tasks, Transformer in computer vision not only requires inheriting a bit of dynamic attention and global context, but also needs to introduce features concerning noise reduction, shifting, and scaling invariance of objects. Therefore, here we take a step forward to study the structural characteristics of Transformer and convolution and propose an architecture search method-Vision Transformer with Convolutions Architecture Search (VTCAS). The high-performance backbone network searched by VTCAS introduces the desirable features of convolutional neural networks into the Transformer architecture while maintaining the benefits of the multi-head attention mechanism. The searched block-based backbone network can extract feature maps at different scales. These features are compatible with a wider range of visual tasks, such as image classification (32 M parameters, 82.0% Top-1 accuracy on ImageNet-1K) and object detection (50.4% mAP on COCO2017). The proposed topology based on the multi-head attention mechanism and CNN adaptively associates relational features of pixels with multi-scale features of objects. It enhances the robustness of the neural network for object recognition, especially in the low illumination indoor scene.

cs.CV↗

arXiv2022

Bonds intersecting long paths in $k$-connected graphs

A well-known question of Gallai (1966) asked whether there is a vertex which passes through all longest paths of a connected graph. Although this has been verified for some special classes of graphs such as outerplanar graphs, circular arc graphs, and series-parallel graphs, the answer is negative for general graphs. In this paper, we prove among other results that if we replace the vertex by a bond, then the answer is affirmative. A bond of a graph is a minimal nonempty edge-cut. In particular, in any 2-connected graph, the set of all edges incident to a vertex is a bond, called a vertex-bond. Clearly, for a 2-connected graph, a path passes through a vertex $v$ if and only if it meets the vertex-bond with respect to $v$. Therefore, a very natural approach to Gallai's question is to study whether there is a bond meeting all longest paths. Let $p$ denote the length of a longest path of connected graphs. We show that for any 2-connected graph, there is a bond meeting all paths of length at least $p-1$. We then prove that for any 3-connected graph, there is a bond meeting all paths of length at least $p-2$. For a $k$-connected graph $(k\ge3)$, we show that there is a bond meeting all paths of length at least $p-t+1$, where $t=\Big\lfloor\sqrt{\frac{k-2}{2}}\Big\rfloor$ if $p$ is even and $t=\Big\lceil\sqrt{\frac{k-2}{2}}\Big\rceil$ if $p$ is odd. Our results provide analogs of the corresponding results of P. Wu and S. McGuinness [Bonds intersecting cycles in a graph, Combinatorica 25 (4) (2005), 439-450] also.

math.CO↗

arXiv2021

Visual Sensation and Perception Computational Models for Deep Learning: State of the art, Challenges and Prospects

Visual sensation and perception refers to the process of sensing, organizing, identifying, and interpreting visual information in environmental awareness and understanding. Computational models inspired by visual perception have the characteristics of complexity and diversity, as they come from many subjects such as cognition science, information science, and artificial intelligence. In this paper, visual perception computational models oriented deep learning are investigated from the biological visual mechanism and computational vision theory systematically. Then, some points of view about the prospects of the visual perception computational models are presented. Finally, this paper also summarizes the current challenges of visual perception and predicts its future development trends. Through this survey, it will provide a comprehensive reference for research in this direction.

cs.AI↗