Robust clustering of functional directional data

A robust approach for clustering functional directional data is proposed. The proposal adapts “impartial trimming” techniques to this particular framework. Impartial trimming uses the dataset itself to tell us which appears to be the most outlying curves. A feasible algorithm is proposed for its practical implementation justified by some theoretical properties. A “warping” approach is also introduced which allows including controlled time warping in that robust clustering procedure to detect typical “templates”. The proposed methodology is illustrated in a real data analysis problem where it is applied to cluster aircraft trajectories.

Water-based binder preparation and full-color printing implementation of a self-developed 3D printer

Purpose The purpose of this study was to prepare water-based binders, which aimed to avoid printhead blockage and to improve dimensional accuracy of inkjet 3D printing (3DP) technology, and a feasible algorithm of full-color printing was realized. Design/methodology/approach A self-developed color 3D printer was made by using a piezoelectric printhead of Epson Dx-5. Several water-based binders and corresponding gypsum composite powders were prepared, and the optimum binder-powder assembly was then determined through elementary adhesive testing and roller paving testing. Full-color printing was implemented based on halftoning algorithms that used different threshold matrices for different ink channels, and the performances of various algorithms were evaluated in terms of both subjective and objective indices. Findings The optimum binder-powder assembly can solve the jamming problem of printhead and realize agreeable dimensional accuracy with the relative error less than 2.5% owing to the satisfying boundary diffusion control ability. And the determined halftone algorithm was verified to be agreeable for 3D color printing. Originality/value The prepared approach of water-based binders and gypsum composite powders can be applied to similar 3DP systems even if different materials are introduced. And the used halftone algorithms provide feasible guidelines to the implementation of 3D full-color printing.

An Algorithm for Fluid–Solid Coupling Based on SPH Method and Its Preliminary Verification

Based on the fundamental theory of smoothed-particle hydrodynamics (SPH), a feasible algorithm for fluid–solid coupling on interface is applied to describe the dynamic behavior of fluid and solid by utilizing continuum mechanics governing equations. Numerical simulation is conducted based on the proposed SPH model and the fluid–solid interface coupling algorithm, and good agreement is observed with the experiment results. It is shown in the results that the present SPH model is able to effectively and accurately simulate the free-surface flow of fluid, deformation of the elastic solid and the fluid–solid impacting.

Review on Transmission Expansion Planning Models

Transmission expansion planning has become a complicated procedure more than any time it was with the rapid growth of the transmission networks, therefore, this work summarizes the works had been done before regarding this topic. This review classifies the existing works from many sides such as, solution methods, planning horizon and from the modeling prospective in order to facilitate the other researcher’s works in this hot area to get a feasible algorithm academically and commercially. The drawbacks of the TEP procedure and some recommendations are also included.

How Design Quality Improves with Increasing Computational Abilities: General Formulas and Case Study of Aircraft Fuel Efficiency

It is known that the problems of optimal design are NP-hard – meaning that, in general, a feasible algorithm can only produce close-to-optimal designs. The more computations we perform, the better design we can produce. In this paper, we theoretically derive quantitative formulas describing how the design qualities improves with the increasing computational abilities. We then empirically confirm the resulting theoretical formula by applying it to the problem of aircraft fuel efficiency.

A Community Detection Algorithm Based on Node Degree Difference and Node Similarity

This paper proposes an algorithm called DDSCDA, which is based on the concepts of the node degree difference and the node similarity. In the algorithm, we iteratively extract the node from the network with larger degree and certified the node as a kernel node, then take the kernel node as the founder or initiator of a community to attract its neighbors to join in that community; by doing so, we obtain a partition corresponding to a coarse-grained community structure of the network. Finally taken the coarse-grained community as a starting point, we use the strategy of LPA to propagate labels through the network further. At the end of the algorithm, we obtain the final community structure. We compared the performance with classical community detection algorithms such as LPA, LPAm, FastQ, etc., the experimental results have manifested that our proposal is a feasible algorithm, can extract higher quality communities from the network, and outperforms the previous algorithms significantly.