Fast Construction Method Research Articles

Autonomous collision avoidance method for MASSs based on precise potential field modelling and COLREGs constraints in complex sailing environments

Autonomous collision avoidance (CA) for maritime autonomous surface ships (MASSs) in complex navigational environments requires accurate environment modelling and efficient CA algorithms. This study proposes a fast construction method for complex environmental potential field models applicable to vector charts. It accurately represents all complex static obstacles, including concave polygons, and dynamically adjusts the range of influence of a potential field according to its danger level. For dynamic ships, a dynamic obstacle modelling method, based on the quaternion ship domain, is designed to highlight the uncertain motion characteristics of ships. Based on the coupled modelling of dynamic and static obstacles, the virtual potential field of target ships, constrained by the International Regulations for Preventing Collisions at Sea (COLREGs), was constructed. By combining the first-order Nomoto model and optimal field prediction strategy, an optimal CA path, satisfying ship dynamics and COLREGs constraints, was realised, and the local optimal problem of the traditional artificial potential field method was solved. Simulation results show that the proposed method accomplishes fast and accurate modelling of complex environments and realises autonomous path planning and real-time multivessel CA tasks for MASSs in complex water considering the COLREGs constraints. Thus, the proposed method can be implemented in actual ships.

NPS COMPOSITE BEAMS AND COLUMNS USED FOR THE ODENSE UNIVERSITY HOSPITAL

AbstractThis document presents the case study of the Odense University Hospital, built with the NPS steel‐concrete composite frame. This is one of the most challenging projects currently in Europe: 250,000 square meters to be built in just over three years. The client has taken up the challenge of respecting timeframe and budget by focusing on offsite construction and digitalization of processes. Time constrains, safety and sustainability are the three main drivers of the project. Among these, the strict delivery time represents the main critical aspect. The expected turnkey delivery in 2022 assumed the choice of an extremely simple and fast construction method. Further advantages of using steel‐concrete composite structures with reference to the Odense University Hospital Case are explained.

Research on the Fast Construction Method of Basic Geographic Framework of 3D Smart Community

In order to promote the reform and innovation of social governance system, create "community brain" and build digital twin community in digital space, the hierarchical and household-level three-dimensional basic geographic framework plays the role of data base. Based on the key technologies such as deep learning change monitoring, batch building and rendering of hierarchical household 3D models on the Web side, and multi-source address matching, this paper explores and realizes the technical route of quickly building hierarchical household-level 3D basic geographic framework of 3D smart communities. Through the technique of dynamic rendering monomer, a three-dimensional model visualization platform of oblique photography is built, which effectively integrates various government resources of people, houses, things and things, and realizes socialization, intelligence and specialization of social governance and convenience services.

Study on the performance of the new composite thermal insulation lining for the railway operational tunnel in cold regions

In railway tunnels located in cold regions, frost damage is constantly emerging, which seriously affects the safety of railway tunnel operations. While having general thermal insulation effects, thermal insulation measures developed in previous studies have not solved the problem of frost damage in operational railway tunnels. To fill this gap, this paper puts forward a new composite thermal insulation lining. Firstly, through numerical simulation, this new composite thermal insulation lining was verified to have better mechanical properties and insulation effects than general steel plate thermal insulation lining. The fast construction method of thermal insulation lining is proposed to have excellent construction efficiency and great economic and social benefits. According to field monitoring data, the outer surface temperature of the lining reached about 5 °C in winter after the new composite thermal insulation lining was added, which fundamentally inhibited the formation of ice and effectively avoided frost damage. At the coldest moment in time, the temperature of the secondary lining was about 9 °C higher than without thermal insulation lining. In summary, compared with existing anti-freeze technology, the new composite thermal insulation lining has better thermal insulation capacity, can be constructed faster, and offers clear economic benefits.

Multi-objective two-level medical facility location problem and tabu search algorithm

The medical facility location problem has attracted increasing attention in recent years because the rational layout of medical facilities plays an important role in implementing the hierarchical diagnosis and treatment system in many countries. To promote the implementation of a hierarchical diagnosis and treatment system, a two-level medical facility location problem with multiple patient flows between demand points and medical facilities is studied in this paper. We use a direct interpretation of the two-level medical facility location problem as a multi-objective problem to effectively balance different conflicting objectives. Based on the multi-objective tabu search algorithm and the fast construction method of the Pareto non-dominated solution, we also propose a solution approach to yield a set of solutions that can represent the trade-offs among conflicting objectives. The applicability and validation of the presented model and performance of the proposed optimization approach are evaluated using a real case. The experimental results not only indicate that the proposed solution approach can effectively solve the two-level medical facility location problem, but also suggest that the presented model can provide significant results in determining locations for medical facilities.

A Fast Construction Method of Resonance Compensation Network for Electric Vehicle Wireless Charging System

When constructing an electric vehicle (EV) wireless charging system, limited by manufacturing technology and measurement errors, the capacitance and inductance in the impedance matching network will inevitably produce parameter deviations, which will cause tuning difficulties and even burn the power supply. In order to solve these problems, this article proposes a fast and accurate tuning technique based on a double-sided L3C compensation network with a capacitor matrix. The tuning method derived from theoretical analysis can be summarized as: tuning capacitor can achieve fast matching; fine adjusting the equivalent inductance can achieve precise matching and power zero-voltage switching. After resonance matching, the capacitors on the capacitor matrix can be removed and welded together, and an inductor can be used instead of equivalent inductance, so the technology is low cost, fast, and safe. In order to verify the tuning method, a 3-kW EV wireless charging system was developed. Experimental results show that the proposed method makes the system resonate rapidly and maintain stability, and the inverter is also easy to implement zero-voltage switching.

Fast Radio Map Construction by using Adaptive Path Loss Model Interpolation in Large-Scale Building.

The radio map construction is usually time-consuming and labor-sensitive in indoor fingerprinting localization. We propose a fast construction method by using an adaptive path loss model interpolation. Received signal strength (RSS) fingerprints are collected at sparse reference points by using multiple smartphones based on crowdsourcing. Then, the path loss model of an access point (AP) can be built with several reference points by the least squares method in a small area. Afterwards, the RSS value can be calculated based on the constructed model and corresponding AP’s location. In the small area, all models of detectable APs can be built. The corresponding RSS values can be estimated at each interpolated point for forming the interpolated fingerprints considering RSS loss, RSS noise and RSS threshold. Through combining all interpolated and sparse reference fingerprints, the radio map of the whole area can be obtained. Experiments are conducted in corridors with a length of 211 m. To evaluate the performance of RSS estimation and positioning accuracy, inverse distance weighted and Kriging interpolation methods are introduced for comparing with the proposed method. Experimental results show that our proposed method can achieve the same positioning accuracy as complete manual radio map even with the interval of 9.6 m, reducing 85% efforts and time of construction.

Virtual Display and Interactive Experience Platform of Farming Culture Based on Unity3D

Aiming at the problem that the transmission mode of Chinese farming cultural contents is limited by time, region and platform, in this paper, a virtual display and interactive experience platform of farming culture is developed based on the technologies of virtual exhibition and interactive experience. Aiming at the time-consuming problem of model batch loading in virtual farming scene, this paper presents a fast construction method of virtual scene. Aiming at the problem that the subtitle, voice and scene can’t synchronize in the 3D virtual scene, a fixed point triggering method is proposed in this paper. Aiming at the problem that people cannot break the limitation of time and geographical to experience farming activities, this paper integrates an interactive VR experience module for the common crops with the device of HTC Vive. The experiment shows that the developed platform can comprehensively sort out and excavate the origin of farming culture, the evolution of farming methods and the formation of typical agroecosystems by integrating the technologies of virtual display, interaction and roaming. Moreover, it can provide the experience of the farming activities for users and offer a kind of new method for cultural protection and publicity.

Unified equivalent frame method for post-tensioned flat plate slab structures

The post-tensioned (PT) flat plate slab system is commonly used in practice, and this simple and fast construction method is also considered to be a very efficient method because it can provide excellent deflection and crack control performance under a service load condition and consequently can be advantageous when applying to long-span structures. However, a detailed design guideline for evaluating the lateral behavior of the PT flat plate slab system is not available in current design codes. Thus, typical design methods used for conventional reinforced concrete (RC) flat plate slab structures have inevitably been adopted in practice for the lateral load design of PT flat plate structures. In the authors\' previous studies, the unified equivalent frame method (UEFM) was proposed, which considers the combined effect of gravity and lateral loads for the lateral behavior analysis of RC flat plate slab structures. The aim of this study is to extend the concept of the UEFM to the lateral analysis of PT flat plate slab structures. In addition, the stiffness reduction factors of torsional members on interior and exterior equivalent frames were newly introduced considering the effect of post-tensioning. Test results of various PT flat plate slab-column connection specimens were collected from literature, and compared to the analysis results estimated by the extended UEFM.

Cyclic behavior of prefabricated circular composite columns with low steel ratio

Improved economy and speed of construction can be achieved through the use of prefabricated structural members. As a step toward the advancement of prefabricated substructures, a precast composite column for seismic regions is proposed in this paper. Concrete-encased composite columns with core structural steel can be utilized for a fast construction method using steel connections. Six concrete-encased composite specimens with low steel ratio were fabricated. Quasi-static tests were conducted to investigate the cyclic response of the prefabricated composite columns. For composite columns with bolt connections, the cyclic behavior in terms of ultimate load and post-cracking behavior was enhanced significantly as the transverse reinforcement ratio increases. Higher prestressing gave greater flexural strength to the composite columns with prestressing and better energy absorption capacity, while displacement ductility of the prestressed composite column was decreased as the prestressing increased.

A Fast KD-Tree Construction Method by Probing the Optimal Splitting Plane Heuristically

In the field of ray-tracing based photo-realistic rendering,kd-tree is used as an important acceleration structure.This paper focuses on the effective construction of kd-tree,and proposes a novel and fast construction method which is based on the binning algorithm.The method is composed of two main steps.Firstly,by analyzing the SAH cost function,the method determines the most-likely sub-span which holds the splitting plane.Secondly,sub-sampling is used on the resulted span to get much better approximation to the optimal splitting plane.Moreover,the paper discusses the exiting schemes on binning termination condition,points out their problems,and proposes a more reasonable termination condition.The experimental results show that the novel approach is effective.Compared with the previous works,it decreases the construction overhead,improves the quality of generated kd-tree,and the construction procedure is more robust as well.

Fast component-by-component construction of rank-1 lattice rules with a non-prime number of points

The component-by-component construction algorithm constructs the generating vector for a rank-1 lattice one component at a time by minimizing the worst-case error in each step. This algorithm can be formulated elegantly as a repeated matrix-vector product, where the matrix-vector product expresses the calculation of the worst-case error in that step. As was shown in an earlier paper, this matrix-vector product can be done in time O ( n log ( n ) ) and with memory O ( n ) when the number of points n is prime. Here we extend this result to general n to obtain a total construction cost of O ( sn log ( n ) ) and memory of O ( n ) for a rank-1 lattice in s dimensions with n points. We thus obtain the same big-Oh result as for n prime. As was the case for n prime, the main calculation cost is significantly reduced by using fast Fourier transforms in the matrix-vector calculation. The number of fast Fourier transforms is dependent on the number of divisors of n and the number of prime factors of n. It is believed that the intrinsic structure present in rank-1 lattices and exploited by this fast construction method will deliver new insights in the applicability of these lattices.

An effective wavelet matrix transform approach for efficient solutions of electromagnetic integral equations

An effective numerical method based on wavelet matrix transforms for efficient solution of electromagnetic (EM) integral equations is proposed. Using the wavelet matrix transform produces highly sparse moment matrices which can be solved efficiently. A fast construction method for various orthonormal or nonorthonormal wavelet basis matrices is also given. It has been found that using nonsimilarity wavelet matrix transforms such as nonsimilarity nonorthonormal cardinal spline wavelet (NSNCSW) transform, one can obtain a much higher compression rate and much better accuracy of the approximate solutions than using similarity wavelet transforms such as Daubechies' (1992) orthonormal wavelet (DOW) transform. Numerical examples are given to show the validity and effectiveness of the method.