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Browse AllThis paper presents a generalizable geometric framework for rapid on-demand generation of multi-UAV formations with arbitrary 2D geometries and user-specified scalable scales. First, vertices, edge intersections and edges are extracted from a user-defined formation template to enable parametric description of both simple and composite formation geometries. Second, boundary interpolation, edge expansion and recursive internal expansion are integrated to synthesize hierarchical multi-layer UAV deployment point sets under a controllable expansion ratio. Third, a geometric distortion metric is proposed to optimize UAV node indexing and formation reconstruction while preserving inter-node topological consistency. Algorithmic derivations, complexity analysis and simulation assumptions are further elaborated. Simulation results verify that the proposed method preserves geometric fidelity of target formations while delivering superior scalability and spatial coverage, rendering it well-suited for emergency transport, aerial surveying and low-altitude cooperative missions in dense urban environments.
This study investigates the governing characteristics of ice resistance encountered by icebreakers operating in multi-year ice regions, with particular emphasis on the effects of bow truncation length, vessel speed, and ice thickness. A numerical simulation framework was developed using the finite element platform LS-PrePost to reproduce ice bending, failure, and ship–ice interaction throughout the icebreaking process. The numerical predictions were subsequently validated against physical model test data. The results indicate that ice resistance exhibits an increasing trend as the bow truncation length, navigation speed, and ice thickness increase. The ice resistance of different bow truncation lengths in the multi-year ice area is different. By truncating the model ship at different positions from the bow and analyzing the ratio of the ice resistance of the truncated models to that of the full-scale model, researchers can better understand the effects of bow size. This can provide a theoretical basis for conducting ice resistance tests with truncated model ships in a limited-scale ice water tank, and has certain practical value for the design and optimization of the icebreaker’s hull lines.
To address the lack of safe and effective on-site vehicle blocking and control methods in the event of fires or other emergencies in extra-long tunnels — which can significantly reduce traffic safety risks and prevent secondary accidents — this study proposes a novel barrier-free light–smoke curtain interception method. The method integrates conventional traffic safety warning facilities (gantry-mounted variable message signs and audio–visual alarms) with two light–smoke curtain interception images to form a composite early-warning and interception system. Driving simulation experiments were conducted to comprehensively evaluate its warning effectiveness, interception performance, and operational safety in comparison with methods employing only traditional warning facilities or light curtain images. Furthermore, field drills were performed to validate its real-world applicability and interception effectiveness under both daytime and nighttime conditions. The main findings are as follows: 1) The fixation ratio and interception success rate associated with the proposed method were significantly higher than those of the other two methods, demonstrating enhanced visual attention and superior warning and interception performance. 2) The maximum deceleration observed with the proposed method was lower than that of the light curtain–only method and did not trigger emergency braking, thereby indicating high operational stability and driver comfort. 3) In field drills, after activation of the interception equipment, only one and two vehicles entered the tunnel under daytime and nighttime conditions, respectively, and full control of on-site vehicles was achieved within two minutes without any traffic accidents, verifying the system’s rapid response and effective safety assurance.














