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An efficient exhaustive search for the discretizable Distance Geometry Problem with interval data

Mucherino A., Lin J.-H.

Annals of Computer Science and Information Systems

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2019

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Vol. 18

135--141

EN

The Distance Geometry Problem (DGP) asks whether a simple weighted undirected graph can be realized in a given space (generally Euclidean) so that a given set of distance constraints (associated to the edges of the graph) is satisfied. The Discretizable DGP (DDGP) represents a subclass of instances where the search space can be reduced to a discrete domain having the structure of a tree. In the ideal case where all distances are precise, the tree is binary and one singleton, representing one possible position for a vertex of the graph, is associated to every tree node. When the distance information is however not precise, the uncertainty on the distance values implies that a three-dimensional region of the search space needs to be assigned to some nodes of the tree. By using a recently proposed coarse-grained representation for DDGP solutions, we extend in this work the branch-and-prune (BP) algorithm so that it can efficiently perform an exhaustive search of the search domain, even when the uncertainty on the distances is important. Instead of associating singletons to nodes, we consider a pair consisting of a box and of a most-likely position for the vertex in this box. Initial estimations of the vertex positions in every box can be subsequently refined by using local optimization. The aim of this paper is two-fold: (i) we propose a new simple method for the computation of the three-dimensional boxes to be associated to the nodes of the search tree; (ii) we introduce the resolution parameter ρ, with the aim of controling the similarity between pairs of solutions in the solution set. Some initial computational experiments show that our algorithm extension, differently from previously proposed variants of the BP algorithm, is actually able to terminate the enumeration of the solution set by providing solutions that differ from one another accordingly to the given resolution parameter.

2

Geo-textiles for Side Slope Protection: Preparation and Characteristics

Hsieh J.-C., Lin C.-W., Lou C.-W., Hsing W.-H., Hsieh C.-T., Kuo C.-Y., Lin J.-H.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 1 (121)

102--107

EN

The vegetation blanket is the most common choice for soil and water preservation. This is a feasible method that protects the land and environment according to basic agriculture and engineering theories. This study manufactured eco-friendly nonwoven vegetation blankets by using cotton fibers, far-infrared fibers, PLA fibers, and low melting-point fibers at a 1:1:7:1 ratio. This ratio yielded from the pilot study provides the resulting vegetation blankets’ optimum air permeability and water absorption. This study further finds that a needle-punching density of 30 needles/cm2 allows fibers to lie in a loose structure, and therefore yielding the optimum air permeability and water absorption. In plant growth evaluation, for nonwoven vegetation blankets that contain 50 wt% far-infrared fibers, the plant growth length is 1.3 times greater than that of blankets with 10 wt% far-infrared fibers. This result proves that far-infrared fibers have usually been applied to plant growth.

PL

Mata wegetacyjna jest najczęściej wybieraną formą ochrony zbocza dla zapewnienia odpowiedniego nawodnienia w celu wzrostu roślin. Jest to metoda, która chroni ziemię i środowisko naturalne zgodnie z zaleceniami nauk rolniczych. W artykule opisano otrzymywanie ekologicznej włókninowej maty wegetacyjnej z włókien bawełnianych, włókien ultraczułych na podczerwień, włókien polilaktydowych oraz włókien o niskiej temperaturze topnienia w stosunku 1:1:1:7. Wskaźnik ten, uzyskany z badania pilotażowego, zapewnia optymalną przepuszczalność powietrza i wchłanianie wody. Stwierdzono ponadto, że gęstość igłowania 30 igieł/cm2 umożliwia luźne ułożenie włókien, a więc pozwala na uzyskanie optymalnej przepuszczalności powietrza i absorpcji wody. W ocenie wzrostu roślin, na włókninowych matach wegetacyjnych, które zawierają 50% wagowych włókien ultraczułych na podczerwień, długość wzrostu roślin jest 1,3 razy większa, niż mat z 10% wagowymi włókien ultraczułych na podczerwień. Użycie włókien ultraczułych na podczerwień jest korzystne dla produkcji eko-włóknin zabezpieczających zbocza.

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Inter-/Intra-Laminar Reinforced Hybrid Fibre Composites by Needle Punching and Thermal Bonding: Evaluation of Mechanical and Static Puncture Properties

Li T.-T., Wang R., Lou C.-W., Pan Y.-J., Hsieh C.-T., Lin J.-H.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 4 (118)

84--91

EN

This study comparatively presents the static puncture property of different structures of intra-/inter-laminar reinforced hybrid composites via needle punching and thermal bonding techniques. The tensile and bursting properties of two composites with inter-laminar reinforcement by needle-punching and inter-and-intra- laminar reinforcement by both needle punching and using Kevlar fibres were also evaluated comparatively. The significance of process parameters including the low-melting PET fibre content, take-up speed of the punching machine, the plied orientation between the nonwoven and fabric and thermal bonding on the static puncture resistance was firstly investigated to seek out the significant parameters. The effects of significant processing parameters on static puncture and mechanical properties were explored afterwards. The research result shows that the plied orientation, low-melting PET content and thermal bonding affect the static puncture resistance most significantly. The maximum tensile strength and bursting strength occurred when hybrid composites after thermal bonding were composed of parallel-plied nonwovens and 90°-orientated glass fabric, as well as 70 wt% low-melting PET fibres. Recycled Kevlar fibre reinforcement dissipates additional static puncture resistance, and makes the static puncture resistance higher, as well as the tensile and bursting strengths for resultant hybrid fibre composites. Employing recycled Kevlar fibres is economical for the fabrication of hybrid composites. Diversified economical hybrid composites will be applied as a wall interlayer or garment interlining in the future.

PL

Przedstawiono porównawcze omówienie statycznej wytrzymałości na przebicie różnych hybrydowych kompozytowych wzmocnionych struktur laminarnych. Badano wytrzymałość na rozciąganie i przerwanie różnych wariantów kompozytów zarówno igłowanych jak i łączonych termicznie, w tym takich, w których stosowano do wzmocnienia włókna Kevlar. Badano istotność wpływu różnych parametrów na statyczną wytrzymałość na przebicie. Stwierdzono znaczny wpływ orientacji igłowania i zawartości niskotopliwego PET.