As technology's influence grows, it is critical that engineers take a greater role in public and private leadership. Most engineering students, however, are not exposed to formal studies in leadership development....
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This study focused on the buckling characteristics of egg-shaped shells with single crack and double cracks under axial pressure. First, the geometric parameters of the egg-shaped shell were designed, and a numerical ...
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This study focused on the buckling characteristics of egg-shaped shells with single crack and double cracks under axial pressure. First, the geometric parameters of the egg-shaped shell were designed, and a numerical model of the egg-shaped shell was established. Then, the initial crack was introduced into the equatorial weld of the egg-shaped shell, and the effects of the crack on the buckling characteristics under different wall thicknesses were explored, as were the effects of the single crack direction, double crack angle and spacing on the buckling characteristics. Finally,crack-free, single crack and double crack egg-shaped shells were fabricated from Q235 steel. The buckling loads and failure modes of the three egg-shaped shells were obtained via axial compression experiments. The numerical critical buckling loads and buckling modes were compared with the experimental results to verify the accuracy of the numerical model. The results of this study are valuable for the design of egg-shaped shells under axial loading.
In this work,the combined addition of strontium/indium(Sr/In)to the magnesium anode for Mg-Air Cells is investigated to improve discharge performance by modifying the anode/electrolyte *** exists as solid solution ato...
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In this work,the combined addition of strontium/indium(Sr/In)to the magnesium anode for Mg-Air Cells is investigated to improve discharge performance by modifying the anode/electrolyte *** exists as solid solution atoms in theα-Mg matrix without its second-phase generation,and at the same time facilitates grain refinement,dendritic segregation and Mg17Sr2-phases *** discharge operation,Sr modifies the film composition via its compounds and promoted the redeposition of In at the substrate/film interface;their co-deposition behavior on the anodic reaction surface enhances anode reaction kinetics,suppresses the negative difference effect(NDE)and mitigates the“chunk effect”(CE),which is contributed to uniform dissolution and low self-corrosion hydrogen evolution rate(HER).Therefore,Mg-Sr-xIn alloy anodes show excellent discharge performance,e.g.,0.5Sr-1.0In shows an average discharge voltage of 1.4234 V and a specific energy density of 1990.71 Wh kg^(-1)at 10 mA cm^(-2).Furthermore,the decisive factor(CE and self-discharge HE)for anodic efficiency are quantitively analyzed,the self-discharge is the main factor of cell efficiency ***,all Mg-Sr-xIn anodes show anodic efficiency greater than 60%at high current density(≥10 mA cm^(-2)),making them excellent candidate anodes for Mg-Air cells at high-power output.
The present research evaluates optical angular momentum's (OAM) performance in challenging atmospheric conditions and emphasizes its significance in free space optical (FSO) communication systems. It has been demo...
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The goal of infrared and visible image fusion(IVIF)is to integrate the unique advantages of both modalities to achieve a more comprehensive understanding of a scene. However, existing methods struggle to effectively h...
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The goal of infrared and visible image fusion(IVIF)is to integrate the unique advantages of both modalities to achieve a more comprehensive understanding of a scene. However, existing methods struggle to effectively handle modal disparities,resulting in visual degradation of the details and prominent targets of the fused images. To address these challenges, we introduce Prompt Fusion, a prompt-based approach that harmoniously combines multi-modality images under the guidance of semantic prompts. Firstly, to better characterize the features of different modalities, a contourlet autoencoder is designed to separate and extract the high-/low-frequency components of different modalities, thereby improving the extraction of fine details and textures. We also introduce a prompt learning mechanism using positive and negative prompts, leveraging Vision-Language Models to improve the fusion model's understanding and identification of targets in multi-modality images, leading to improved performance in downstream tasks. Furthermore, we employ bi-level asymptotic convergence optimization. This approach simplifies the intricate non-singleton non-convex bi-level problem into a series of convergent and differentiable single optimization problems that can be effectively resolved through gradient *** approach advances the state-of-the-art, delivering superior fusion quality and boosting the performance of related downstream tasks. Project page: https://***/hey-it-s-me/PromptFusion.
In this digital world where an enormous volume of textual material is growing on the internet every single day, there is a great need for systems that can produce human-like summaries automatically. In the past, a num...
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This paper addresses the verification of strong currentstate opacity with respect to real-time observations generated from a discrete-event system that is modeled with time labeled Petri nets. The standard current-sta...
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This paper addresses the verification of strong currentstate opacity with respect to real-time observations generated from a discrete-event system that is modeled with time labeled Petri nets. The standard current-state opacity cannot completely characterize higher-level security. To ensure the higher-level security requirements of a time-dependent system, we propose a strong version of opacity known as strong current-state opacity. For any path(state-event sequence with time information)π derived from a real-time observation that ends at a secret state, the strong current-state opacity of the real-time observation signifies that there is a non-secret path with the same real-time observation as π. We propose general and non-secret state class graphs, which characterize the general and non-secret states of time-dependent systems, respectively. To capture the observable behavior of non-secret states, a non-secret observer is ***, we develop a structure called a real-time concurrent verifier to verify the strong current-state opacity of time labeled Petri nets. This approach is efficient since the real-time concurrent verifier can be constructed by solving a certain number of linear programming problems.
Recently, redactable blockchain has been proposed and leveraged in a wide range of real systems for its unique properties of decentralization, traceability, and transparency while ensuring controllable on-chain data r...
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Recently, redactable blockchain has been proposed and leveraged in a wide range of real systems for its unique properties of decentralization, traceability, and transparency while ensuring controllable on-chain data redaction. However, the development of redactable blockchain is now obstructed by three limitations, which are data privacy breaches, high communication overhead, and low searching efficiency, respectively. In this paper, we propose PriChain, the first efficient privacy-preserving fine-grained redactable blockchain in decentralized settings. PriChain provides data owners with rights to control who can read and redact on-chain data while maintaining downward compatibility, ensuring the one who can redact will be able to read. Specifically, inspired by the concept of multi-authority attribute-based encryption, we utilize the isomorphism of the access control tree, realizing fine-grained redaction mechanism, downward compatibility, and collusion resistance. With the newly designed structure, PriChain can realize O（n） communication and storage overhead compared to prior O（n2） schemes. Furthermore, we integrate multiple access trees into a tree-based dictionary, optimizing searching efficiency. Theoretical analysis proves that PriChain is secure against the chosen-plaintext attack and has competitive complexity. The experimental evaluations show that PriChain realizes 10× efficiency improvement of searching and 100× lower communication and storage overhead on average compared with existing schemes.
With the development of cyber-physical systems,system security faces more risks from cyber-attacks. In this work,we study the problem that an external attacker implements covert sensor and actuator attacks with resour...
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With the development of cyber-physical systems,system security faces more risks from cyber-attacks. In this work,we study the problem that an external attacker implements covert sensor and actuator attacks with resource constraints(the total resource consumption of the attacks is not greater than a given initial resource of the attacker) to mislead a discrete event system under supervisory control to reach unsafe states. We consider that the attacker can implement two types of attacks: One by modifying the sensor readings observed by a supervisor and the other by enabling the actuator commands disabled by the supervisor. Each attack has its corresponding resource consumption and remains covert. To solve this problem, we first introduce a notion of combined-attackability to determine whether a closedloop system may reach an unsafe state after receiving attacks with resource constraints. We develop an algorithm to construct a corrupted supervisor under attacks, provide a verification method for combined-attackability in polynomial time based on a plant, a corrupted supervisor, and an attacker's initial resource, and propose a corresponding attack synthesis algorithm. The effectiveness of the proposed method is illustrated by an example.
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