A 5+ϵ-approximation algorithm for minimum weighted dominating set in unit disk graph

AbstractWe study the minimum weight dominating set problem in weighted unit disk graph, and give a polynomial time algorithm with approximation ratio 5+ϵ, improving the previous best result of 6+ϵ in [Yaochun Huang, Xiaofeng Gao, Zhao Zhang, Weili Wu, A better constant-factor approximation for weighted dominating set in unit disk graph, J. Comb. Optim. (ISSN: 1382-6905) (2008) 1573–2886. (Print) (Online)]. Combining the common technique used in the above mentioned reference, we can compute a minimum weight connected dominating set with approximation ratio 9+ϵ, beating the previous best result of 10+ϵ in the same work

Diammonium bis­[(2-amino­acetato-κ2 N,O)(2,2′-bipyridine-κ2 N,N′)(N,N-dimethyl­formamide-κO)copper(II)] hexa­cosa­oxidoocta­molybdate(VI)

The title compound, (NH4)2[Cu(C2H4NO2)(C10H8N2)(C3H7NO)]2[Mo8O26], contains a centrosymmetric β-type octa­molybdate anion, two copper(II) complex cations and two ammonium ions. The CuII atom is coordinated in a square-pyramidal geometry by a 2,2′-bipyridine and a 2-amino­acetate ligands in the basal plane and by an O atom of N,N-dimethyl­formamide in the apical position. The anions and cations are linked by N—H⋯O hydrogen bonds into a three-dimensional network

FedForgery: Generalized Face Forgery Detection with Residual Federated Learning

With the continuous development of deep learning in the field of image generation models, a large number of vivid forged faces have been generated and spread on the Internet. These high-authenticity artifacts could grow into a threat to society security. Existing face forgery detection methods directly utilize the obtained public shared or centralized data for training but ignore the personal privacy and security issues when personal data couldn't be centralizedly shared in real-world scenarios. Additionally, different distributions caused by diverse artifact types would further bring adverse influences on the forgery detection task. To solve the mentioned problems, the paper proposes a novel generalized residual Federated learning for face Forgery detection (FedForgery). The designed variational autoencoder aims to learn robust discriminative residual feature maps to detect forgery faces (with diverse or even unknown artifact types). Furthermore, the general federated learning strategy is introduced to construct distributed detection model trained collaboratively with multiple local decentralized devices, which could further boost the representation generalization. Experiments conducted on publicly available face forgery detection datasets prove the superior performance of the proposed FedForgery. The designed novel generalized face forgery detection protocols and source code would be publicly available.Comment: The code is available at https://github.com/GANG370/FedForgery. The paper has been accepted in the IEEE Transactions on Information Forensics & Securit

Ultra-high strength metal matrix composites (MMCs) with extended ductility manufactured by size-controlled powder and spherical cast tungsten carbide

The main challenge of particle reinforced metal matrix composites (MMCs) is balancing strength and ductility. This research uses type 420 stainless steel and spherical cast tungsten carbide (WC/W2C) with a similar powder size and range as raw powders to manufacture laser powder bed fusion (LPBF) 420 + 5 wt% WC/W2C MMCs. LPBF 420 + 5 wt% WC/W2C MMCs contain austenite, martensite, and W-rich carbides (WC/W2C, FeW3C, M6C, and M7C3) from nanometre to micrometre scale. The well-balanced composition creates a crack-free reaction layer between the reinforced particles and matrix. This reaction layer consists of two distinct layers, depending on the element concentration. The LPBF 420 + 5 wt% WC/W2C MMCs achieved an excellent compressive strength of ∼5.5 GPa and a considerable fracture strain exceeding 50 %. The underlying mechanisms for the improved mechanical properties are discussed, providing further insight to advance the application of MMCs via additive manufacturing

Synergistic improvement of pitting and wear resistance of laser powder bed fusion 420 stainless steel reinforced by size-controlled spherical cast tungsten carbides

The spherical cast WC/W2C is selected to produce a martensitic stainless steel-based composite using the laser powder bed fusion technique. W and C reacted with Fe and Cr, creating a strong bond between the particles and the matrix, reducing the wear rate by over 98%. W and C diffuse to the matrix, increasing the hardness over 100 HV0.5. The interface between cast WC/W2C and matrix is sensitive to pitting corrosion through galvanic effects. However, the formation of austenite and WO3 from spherical cast WC/W2C decomposition improves the critical pitting potential and passive film stability

Multi-factor coupling analysis of large-energy events in a kilometer deep mine

Based on the research background of Shandong Lilou Coal Mine, this paper used methods such as on-site investigation, engineering comparison, and on-site monitoring to research on the high-energy events that have occurred in Lilou Coal Mine since 2020, and drew the following conclusions: ①Systematically analyzed the relationship between four influencing factors and high-energy microseismic events including the distribution of abutment pressure, working face “square”, crossing faults, and mining speed, and searched the causes of large energy events. The mining influence range of No.1302 (top) working face is about 30 m behind the face to 170 m in front, and the advanced stress peak is about 70 m in front. The lateral microseismic events are mainly distributed along the gob-side entry, and the whole is offset to the side of the goaf. The distribution of microseismic events at No.1303 working face in the advancing direction of the working face ranges from 15 m behind the face to 200 m in front of the face, and the advanced stress peak is about 80 m in front of the face. The microseismic event at the No.1303 working face is bimodal in the lateral distribution pattern, shifting to the belt grooves. Affected by the wide coal pillar, the stress concentration on the belt grooves is higher than that on the track tunnel. The frequency and energy of microseismic events gradually increased before the “square” of the work face, and stabilized after the “square”. Before crossing the fault, the microseismic events gradually increased, decreased sharply during the crossing, and gradually stabilized after crossing the fault. The peak position of the event was about 40 m in front of the “square” or before the fault. When the mining speed of 1302 (top) working face is 50 m/month and the 1303 working face is 60 m/month, the frequency and energy are the largest. ②By analyzing the inducing factors and locations of large-energy events, large-energy events can be divided into three categories: “energy accumulation type” high-energy events, “fault activation type” high-energy events, and “island structure type” high-energy events, and put forward specific prevention and control measures for different types. The research in this article will provide reference for surrounding mines with similar geological factors and mining technical conditions

PENGARUH GOOD CORPORATE GOVERNANCE, LIKUIDITAS, DAN UKURAN PERUSAHAAN TERHADAP PROFITABILITAS PADA PERUSAHAAN BUMN YANG TERMASUK DALAM IICG DENGAN STRUKTUR MODAL SEBAGAI VARIABEL INTERVENING

Penelitian ini bertujuan untuk menguji pengaruh Good Corporate Governance, likuiditas, dan ukuran perusahaan terhadap profitabilitas, dimediasi oleh struktur modal. Metode penelitian yang digunakan adalah metode penelitian kuantitatif. Populasi dalam penelitian ini adalah perusahaan BUMN yang termasuk dalam IICG. Teknik pengambilan sampel adalah teknik purposive sampling dengan jumlah sampel sebanyak 13 perusahaan. Jenis data yang digunakan adalah data sekunder dan teknik analisis yang digunakan adalah Struktur Equation Model dengan alat uji software SmartPLS. Hasil dalam penelitian menunjukkan bahwa Good Corporate Governance, likuiditas dan ukuran perusahaan berpengaruh signifikan terhadap struktur modal. Hasil penelitian juga menunjukkan bahwa struktur modal memediasi secara penuh pengaruh Good Corporate Governance dan ukuran perusahaan terhadap profitabilitas, namun memediasi parsial pengaruh likuiditas terhadap profitabilitas

Slowly rotating charged black holes in anti-de Sitter third order Lovelock gravity

In this paper, we study slowly rotating black hole solutions in Lovelock gravity (n=3). These exact slowly rotating black hole solutions are obtained in uncharged and charged cases, respectively. Up to the linear order of the rotating parameter a, the mass, Hawking temperature and entropy of the uncharged black holes get no corrections from rotation. In charged case, we compute magnetic dipole moment and gyromagnetic ratio of the black holes. It is shown that the gyromagnetic ratio keeps invariant after introducing the Gauss-Bonnet and third order Lovelock interactions.Comment: 14 pages, no figur

Unveiling the additive-assisted oriented growth of perovskite crystallite for high performance light-emitting diodes.

Solution-processed metal halide perovskites have been recognized as one of the most promising semiconductors, with applications in light-emitting diodes (LEDs), solar cells and lasers. Various additives have been widely used in perovskite precursor solutions, aiming to improve the formed perovskite film quality through passivating defects and controlling the crystallinity. The additive's role of defect passivation has been intensively investigated, while a deep understanding of how additives influence the crystallization process of perovskites is lacking. Here, we reveal a general additive-assisted crystal formation pathway for FAPbI3 perovskite with vertical orientation, by tracking the chemical interaction in the precursor solution and crystallographic evolution during the film formation process. The resulting understanding motivates us to use a new additive with multi-functional groups, 2-(2-(2-Aminoethoxy)ethoxy)acetic acid, which can facilitate the orientated growth of perovskite and passivate defects, leading to perovskite layer with high crystallinity and low defect density and thereby record-high performance NIR perovskite LEDs (~800 nm emission peak, a peak external quantum efficiency of 22.2% with enhanced stability)

GRIK3 rs490647 is a Common Genetic Variant between Personality and Subjective Well-being in Chinese Han Population

Personality and subjective well-being (SWB) have been suggested to be strongly related in previous studies. This study was intended to confirm the relationship between personality and SWB and tried to seek out the genetic variants which underlie both personality and SWB. The subjects were 890 participants from Chinese Han population. We evaluated their personality using the Big Five Inventory (BFI) and used the Satisfaction With Life Scale (SWLS) to reflect their SWB. Five single nucleotide polymorphisms (SNPs) were selected from the literature (rs1426371, rs2164273, rs322931, rs3756290, rs490647) and genotyped for genetic association study. We found negative correlations between neuroticism and SWB. On the contrary, extraversion and agreeableness were positively associated with SWB. Three SNPs (rs2164273, rs3756290, rs490647) out of the five were found to connect with personality (extraversion, neuroticism, conscientiousness and openness to experience) and rs490647 variants of GRIK3 was also associated with SWB. Individuals carrying G allele at this site were predisposed to have lower risk to be neuroticism and greater chance to be extraverted, open and satisfied with their life. In summary, our study revealed that rs490647 might be a good candidate genetic variant for personality and SWB in Chinese Han population