994 research outputs found

    Gender diversity in top management team and firm financial performance: empirical evidence from China

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    In the context of the rapid development of the global economy, a diversified top management team helps companies gain competitive advantage. Gender equality is also receiving increasing attention. In recent years, there is an increasing number of researches about gender diversity in top management team and firm financial performance. The findings of the relationship between the gender diversity of firm financial performance is mixed. Most of these studies have been conducted in Europe and America. There are few empirical studies in China on this topic. This dissertation examined the impact of female executives on firm financial performance. The fixed effects model was adopted in this dissertation to perform regression analysis on the three-year panel data of Chinese listed companies. There is a positive relationship in the result of this paper. The findings of this dissertation make contributions to the methods of the company to optimize the structure of top management team. Key words: gender diversity in top management team; firm financial performance; mediating and moderating factors; listed company in Chin

    Launching a Robust Backdoor Attack under Capability Constrained Scenarios

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    As deep neural networks continue to be used in critical domains, concerns over their security have emerged. Deep learning models are vulnerable to backdoor attacks due to the lack of transparency. A poisoned backdoor model may perform normally in routine environments, but exhibit malicious behavior when the input contains a trigger. Current research on backdoor attacks focuses on improving the stealthiness of triggers, and most approaches require strong attacker capabilities, such as knowledge of the model structure or control over the training process. These attacks are impractical since in most cases the attacker's capabilities are limited. Additionally, the issue of model robustness has not received adequate attention. For instance, model distillation is commonly used to streamline model size as the number of parameters grows exponentially, and most of previous backdoor attacks failed after model distillation; the image augmentation operations can destroy the trigger and thus disable the backdoor. This study explores the implementation of black-box backdoor attacks within capability constraints. An attacker can carry out such attacks by acting as either an image annotator or an image provider, without involvement in the training process or knowledge of the target model's structure. Through the design of a backdoor trigger, our attack remains effective after model distillation and image augmentation, making it more threatening and practical. Our experimental results demonstrate that our method achieves a high attack success rate in black-box scenarios and evades state-of-the-art backdoor defenses.Comment: 9 pages, 6 figure

    Hypergraphs with infinitely many extremal constructions

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    We give the first exact and stability results for a hypergraph Tur\'{a}n problem with infinitely many extremal constructions that are far from each other in edit-distance. This includes an example of triple systems with Tur\'{a}n density 2/92/9, thus answering some questions posed by the third and fourth authors and Reiher about the feasible region of hypergraphs. Our results also provide extremal constructions whose shadow density is a transcendental number. Our novel approach is to construct certain multilinear polynomials that attain their maximum (in the standard simplex) on a line segment and then to use these polynomials to define an operation on hypergraphs that gives extremal constructions.Comment: journal version, Discrete Analysis 2023:18, 34 p

    A Close Look at Lyα Emitters with JWST/NIRCam at z ≈ 3.1

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    We study 10 spectroscopically confirmed Lyα emitters (LAEs) at z ≈ 3.1 in the Ultra Deep Survey field, covered by the James Webb Space Telescope/NIRCam in the Public Release Imaging for Extragalactic Research program. All LAEs are detected in all NIRCam bands from F090W to F444W, corresponding to rest frame wavelengths of 2200 Å to 1.2 μm. Based on morphological analysis of the F200W images, three out of the 10 targets are resolved into pair-like systems with separations of &lt;0.″9, and another three show asymmetric structures. We then construct the spectral energy distributions (SEDs) of these LAEs, which show little to no extinction. All sources, including the pairs, show similar SED shapes, with a prominent flux excess in the F200W band, corresponding to extremely strong [O iii]+Hβ emission lines (EWrest = 740-6500 Å). The median effective radii, stellar mass, and UV slope of our sample are 0.36 kpc, 3.8 × 107 M ⊙, and −2.48, respectively. The average burst age, estimated by stellar mass over star formation rate, is &lt;40 Myr. These measurements reveal an intriguing starbursting dwarf galaxy population lying off the extrapolations of the z ∼ 3 scaling relations to the low-mass end: ∼0.7 dex above the star-forming main sequence, ∼0.35 dex below the mass-size relation, and bluer in the UV slope than typical high-z galaxies at similar UV luminosities. We speculate that these numbers may require a larger main-sequence scatter or tail in the dwarf galaxy regime toward the starburst outliers.</p

    LeCaRDv2: A Large-Scale Chinese Legal Case Retrieval Dataset

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    As an important component of intelligent legal systems, legal case retrieval plays a critical role in ensuring judicial justice and fairness. However, the development of legal case retrieval technologies in the Chinese legal system is restricted by three problems in existing datasets: limited data size, narrow definitions of legal relevance, and naive candidate pooling strategies used in data sampling. To alleviate these issues, we introduce LeCaRDv2, a large-scale Legal Case Retrieval Dataset (version 2). It consists of 800 queries and 55,192 candidates extracted from 4.3 million criminal case documents. To the best of our knowledge, LeCaRDv2 is one of the largest Chinese legal case retrieval datasets, providing extensive coverage of criminal charges. Additionally, we enrich the existing relevance criteria by considering three key aspects: characterization, penalty, procedure. This comprehensive criteria enriches the dataset and may provides a more holistic perspective. Furthermore, we propose a two-level candidate set pooling strategy that effectively identify potential candidates for each query case. It's important to note that all cases in the dataset have been annotated by multiple legal experts specializing in criminal law. Their expertise ensures the accuracy and reliability of the annotations. We evaluate several state-of-the-art retrieval models at LeCaRDv2, demonstrating that there is still significant room for improvement in legal case retrieval. The details of LeCaRDv2 can be found at the anonymous website https://github.com/anonymous1113243/LeCaRDv2

    Toward a density Corr\'{a}di--Hajnal theorem for degenerate hypergraphs

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    Given an rr-graph FF with r≥2r \ge 2, let ex(n,(t+1)F)\mathrm{ex}(n, (t+1) F) denote the maximum number of edges in an nn-vertex rr-graph with at most tt pairwise vertex-disjoint copies of FF. Extending several old results and complementing prior work [J. Hou, H. Li, X. Liu, L.-T. Yuan, and Y. Zhang. A step towards a general density Corr\'{a}di--Hajnal theorem. arXiv:2302.09849, 2023.] on nondegenerate hypergraphs, we initiate a systematic study on ex(n,(t+1)F)\mathrm{ex}(n, (t+1) F) for degenerate hypergraphs FF. For a broad class of degenerate hypergraphs FF, we present near-optimal upper bounds for ex(n,(t+1)F)\mathrm{ex}(n, (t+1) F) when nn is sufficiently large and tt lies in intervals [0,ε⋅ex(n,F)nr−1]\left[0, \frac{\varepsilon \cdot \mathrm{ex}(n,F)}{n^{r-1}}\right], [ex(n,F)εnr−1,εn]\left[\frac{\mathrm{ex}(n,F)}{\varepsilon n^{r-1}}, \varepsilon n \right], and [(1−ε)nv(F),nv(F)]\left[ (1-\varepsilon)\frac{n}{v(F)}, \frac{n}{v(F)} \right], where ε>0\varepsilon > 0 is a constant depending only on FF. Our results reveal very different structures for extremal constructions across the three intervals, and we provide characterizations of extremal constructions within the first interval. Additionally, for graphs, we offer a characterization of extremal constructions within the second interval. Our proof for the first interval also applies to a special class of nondegenerate hypergraphs, including those with undetermined Tur\'{a}n densities, partially improving a result in [J. Hou, H. Li, X. Liu, L.-T. Yuan, and Y. Zhang. A step towards a general density Corr\'{a}di--Hajnal theorem. arXiv:2302.09849, 2023.]Comment: 37 pages, 4 figures, comments are welcom
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