On the cyclic bending behaviour of a hard coating on a ductile substrate with periodic surface hardened regions

AbstractA cyclic bending experiment is designed to investigate the interface fracture behaviour of a hard chromium coating on a ductile substrate with periodic surface hardened regions. The unique deflection pattern of the vertical cracks after they run through the coating and impinge at the interface is revealed experimentally. A simple double-layer elastic beam model is adopted to investigate the interfacial shear stresses analytically. A FE model is employed to compute the stresses of the tri-phase structure under a single round of bending, and to investigate the effect of the loading conditions on the deflection pattern of the vertical cracks at the interface

How to Achieve End-to-end Key Distribution for QKD Networks in the Presence of Untrusted Nodes

Quantum key distribution (QKD) networks are expected to enable information-theoretical secure (ITS) communication over a large-scale network. Most researches on relay-based QKD network assume that all relays are completely trustworthy, but the assumption is unrealistic in a complex network. The current study only analyzes the case of passive attacks by untrusted relays (e.g. eavesdropping). However, active attacks by untrusted relays (e.g. spoofing or interfering with the cooperation between honest nodes) are more serious threats and should not be ignored. Taking both passive and active attacks into account, we propose the ITSBFT-QKD networks to defend against untrusted nodes and achieve end-to-end key distribution. In end-to-end key distribution, multiple participating nodes are required to establish trust relationships and cooperate with each other. To prevent attackers from breaking trust relationship and gaining an unreasonable advantage, we incorporate a byzantine consensus scheme to establish and transmit trust relationships in a global QKD network perspective. Moreover, since the security of traditional consensus schemes is lower than the security requirement of QKD networks, we devise a byzantine fault tolerance (BFT) signature scheme to ensure the information-theoretic security of consensus. It provides a new way to construct signature schemes with point-to-point QKD keys in the presence of untrusted relays or nodes. The security of our scheme is analyzed thoroughly from multiple aspects. Our scheme can accommodate up to $MIN\left( C-1,\lfloor \frac{N-1}{3} \rfloor \right)$ untrusted nodes, where $C$ is the node connectivity of the network and $N$ is the number of nodes in the network. Our scheme provides the highest level of security in currently relay-based QKD networks and will significantly promote the application of QKD networks.Comment: 13 pages,7 figure

Sequential eigen-assignment technique for structural damage identification

This research proposed an eigen-assignment technique for locating and identifying structural damages using an incomplete measurement set. The sequential method is computationally efficient and requires no sensitivity calculations. Established by the finite element method, the mass and stiffness matrices are partitioned and measured partial eigenvectors are expanded to full modes. By matching calculated eigen-pairs with their measured counterparts as the termination criterion, the procedure solves for the stiffness reduction coefficients sequentially using a nonnegative least-squares solution scheme. The proposed approach can still find the damaged locations and the extent of the damage in a structure with much less measured degrees of freedom and even less measured modes than the finite element analysis degrees of freedom. The effectiveness of the technique is demonstrated by solving two cases based on a structure built for a benchmark study by the Group for Aeronautical Research and Technology in Europe (GARTEUR SM-AG19 structure)

Comparison of Radical Scavenging Activity, Cytotoxic Effects and Apoptosis Induction in Human Melanoma Cells by Taiwanese Propolis from Different Sources

Propolis is a sticky substance that is collected from plants by honeybees. We previously demonstrated that propolins A, B, C, D, E and F, isolated from Taiwanese propolis (TP), could effectively induce human melanoma cell apoptosis and were strong antioxidant agents. In this study, we evaluated TP for free radical scavenging activity by DPPH (1,2-diphenyl-2-picrylhydrazyl). The phenolic concentrations were quantified by the Folin–Ciocalteu method. The apoptosis trigger activity in human melanoma cells was evaluated. TP contained a higher level of phenolic compounds and showed strong capability to scavenge free radicals. Additionally, TP1g, TP3, TP4 and TP7 exhibited a cytotoxic effect on human melanoma cells, with an IC(50) of ∼2.3, 2.0, 3.3 and 3.3 μg/ml, respectively. Flow cytometric analysis for DNA fragmentation indicated that TP1g, TP2, TP3 and TP7 could induce apoptosis in human melanoma cells and there is a marked loss of cells from the G2/M phase of the cell cycle. To address the mechanism of the apoptosis effect of TP, we evaluated its effects on induction of apoptosis-related proteins in human melanoma cells. The levels of procaspase-3 and PARP [poly(ADP-ribose) polymerase] were markedly decreased. Furthermore, propolins A, B, C, D, E and F in TP were determined using HPLC. The results indicate that TP is a rich source of these compounds. The findings suggest that TP induces apoptosis in human melanoma cells due to its high level of propolins

Harder Tasks Need More Experts: Dynamic Routing in MoE Models

In this paper, we introduce a novel dynamic expert selection framework for Mixture of Experts (MoE) models, aiming to enhance computational efficiency and model performance by adjusting the number of activated experts based on input difficulty. Unlike traditional MoE approaches that rely on fixed Top-K routing, which activates a predetermined number of experts regardless of the input's complexity, our method dynamically selects experts based on the confidence level in expert selection for each input. This allows for a more efficient utilization of computational resources, activating more experts for complex tasks requiring advanced reasoning and fewer for simpler tasks. Through extensive evaluations, our dynamic routing method demonstrates substantial improvements over conventional Top-2 routing across various benchmarks, achieving an average improvement of 0.7% with less than 90% activated parameters. Further analysis shows our model dispatches more experts to tasks requiring complex reasoning skills, like BBH, confirming its ability to dynamically allocate computational resources in alignment with the input's complexity. Our findings also highlight a variation in the number of experts needed across different layers of the transformer model, offering insights into the potential for designing heterogeneous MoE frameworks. The code and models are available at https://github.com/ZhenweiAn/Dynamic_MoE

RESPONSE SURFACE METHOD FOR UPDATING DYNAMIC FINITE ELEMENT MODELS

ABSTRACT A finite element model of a structure can be updated as certain criteria based on experimental data are satisfied. The updated FE model is considered a better model for future studies in dynamic response prediction, structural modification, and damage identification. A finite element model updating technique incorporating the concept of response surface approximation (RSA) requires no sensitivity calculations and is much easier to implement with a general-purpose finite element code. The proposed updating method was incorporated with MSC.Nastran to solve the updating problem for an H-shaped frame structure. The updated results show that the predicted and experimental modes are correlated well with high MAC values and with a maximum frequency difference of 1.5%. Moreover, the updated parameters provide a physical insight to the modeling of bolted and welded joints of the H-frame structure. INTRODUCTION Finite element model updating [1] is a study in how to combine the strength of both the finite element (analytical) and experimental analyses for studying the dynamic behavior of a structure. Although the finite element (FE) method produces more natural frequencies, mode shapes, and spatial information to characterize the structure, the accuracy of these results usually requires further experimental confirmation. The experimental modal testing, on the other hand, yields fewer modes and less spatial resolution, but generally inspires more confidence in its results. A finite element model of a structure can be updated as certain criteria based on experimental data are satisfied. The updated FE model is considered a better model for future studies in dynamic response prediction, structural modification, and damage identification. In the early years of the development of finite element model updating, most authors studied cases for simulated structures only. In recent years, more and more model updating cases for real structures have been reported, e.g.

Low rank Green's function representations applied to dynamical mean-field theory

Several recent works have introduced highly compact representations of single-particle Green's functions in the imaginary time and Matsubara frequency domains, as well as efficient interpolation grids used to recover the representations. In particular, the intermediate representation with sparse sampling and the discrete Lehmann representation (DLR) make use of low-rank compression techniques to obtain optimal approximations with controllable accuracy. We consider the use of the DLR in dynamical mean-field theory (DMFT) calculations, and in particular, show that the standard full Matsubara frequency grid can be replaced by the compact grid of DLR Matsubara frequency nodes. We test the performance of the method for a DMFT calculation of Sr$_2$RuO$_4$ at temperature $50$K using a continuous-time quantum Monte Carlo impurity solver, and demonstrate that Matsubara frequency quantities can be represented on a grid of only $36$ nodes with no reduction in accuracy, or increase in the number of self-consistent iterations, despite the presence of significant Monte Carlo noise.Comment: 5 pages, 4 figure

Cytotoxic Effect of Recombinant Mycobacterium tuberculosis CFP-10/ESAT-6 Protein on the Crucial Pathways of WI-38 Cells

To unravel the cytotoxic effect of the recombinant CFP-10/ESAT-6 protein (rCFES) on WI-38 cells, an integrative analysis approach, combining time-course microarray data and annotated pathway databases, was proposed with the emphasis on identifying the potentially crucial pathways. The potentially crucial pathways were selected based on a composite criterion characterizing the average significance and topological properties of important genes. The analysis results suggested that the regulatory effect of rCFES was at least involved in cell proliferation, cell motility, cell survival, and metabolisms of WI-38 cells. The survivability of WI-38 cells, in particular, was significantly decreased to 62% with 12.5 μM rCFES. Furthermore, the focal adhesion pathway was identified as the potentially most-crucial pathway and 58 of 65 important genes in this pathway were downregulated by rCFES treatment. Using qRT-PCR, we have confirmed the changes in the expression levels of LAMA4, PIK3R3, BIRC3, and NFKBIA, suggesting that these proteins may play an essential role in the cytotoxic process in the rCFES-treated WI-38 cells

Sequential eigen-assignment technique for structural damage identification

This research proposed an eigen-assignment technique for locating and identifying structural damages using an incomplete measurement set. The sequential method is computationally efficient and requires no sensitivity calculations. Established by the finite element method, the mass and stiffness matrices are partitioned and measured partial eigenvectors are expanded to full modes. By matching calculated eigen-pairs with their measured counterparts as the termination criterion, the procedure solves for the stiffness reduction coefficients sequentially using a nonnegative least-squares solution scheme. The proposed approach can still find the damaged locations and the extent of the damage in a structure with much less measured degrees of freedom and even less measured modes than the finite element analysis degrees of freedom. The effectiveness of the technique is demonstrated by solving two cases based on a structure built for a benchmark study by the Group for Aeronautical Research and Technology in Europe (GARTEUR SM-AG19 structure)