1,507 research outputs found

    A Note on Near-factor-critical Graphs

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    A near-factor of a finite simple graph GG is a matching that saturates all vertices except one. A graph GG is said to be near-factor-critical if the deletion of any vertex from GG results in a subgraph that has a near-factor. We prove that a connected graph GG is near-factor-critical if and only if it has a perfect matching. We also characterize disconnected near-factor-critical graphs.Comment: 4 page

    Tailored Iterated Greedy metaheuristic for a scheduling problem in metal 3D printing

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    This article contributes to the additive manufacturing-based production planning literature by developing a Mixed-Integer Linear Programming (MILP) formulation for the Identical Parallel 3D-Printing Machines Scheduling Problem considering batching, multiple build platforms of restricted sizes, and sequence-independent setup times. Besides, a customized metaheuristic, named the Tailored Iterated Greedy (TIG) Algorithm is developed to solve the new optimization problem. TIGā€™s performance is evaluated through extensive numerical analysis and using a new testbed. It is shown that the customized computational mechanisms improve the optimization performance; statistical analysis is supportive of the significance of the resulting improvements. The developed mathematical model and optimization algorithm can be considered the basis for future developments in the optimization literature of additive manufacturing

    Effects of natto extract on endothelial injury in a rat model

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    Vascular endothelial damage has been found to be associated with thrombus formation, which is considered to be a risk factor for cardiovascular disease. A diet of natto leads to a low prevalence of cardiovascular disease. The aim of the present study was to investigate the effects of natto extract on vascular endothelia damage with exposure to laser irradiation. Endothelial damage both in vitro and in vivo was induced by irradiation of rose bengal using a DPSS green laser. Cell viability was determined by MTS assay, and the intimal thickening was verified by a histological approach. The antioxidant content of natto extract was determined for the free radical scavenging activity. Endothelial cells were injured in the presence of rose bengal irradiated in a dose-dependent manner. Natto extract exhibits high levels of antioxidant activity compared with purified natto kinase. Apoptosis of laser-injured endothelial cells was significantly reduced in the presence of natto extract. Both the natto extract and natto kinase suppressed intimal thickening in rats with endothelial injury. The present findings suggest that natto extract suppresses vessel thickening as a synergic effect attributed to its antioxidant and anti-apoptosis properties

    An investigation on helical gear pair stresses incorporating misalignment and detail modification

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    A finite element approach to investigating the dynamic behavior of helical gear pairs (HGPs) by incorporating misalignment error and detail modifications of tip relief and face-width crowning is presented. Basing on the C code and derived tooth profile formulas, fine finite element models of helical gear pair (HGP) can be constructed parametrically. Also, all elements on the driven teeth surfaces are numbered to identify individual dynamic stresses. After analysis settings, the dynamic contact and fillet bending stresses of a theoretic HGP are first calculated. Then, the maximum stresses with misalignment error are also obtained. Finally, the effect of tooth modification on the dynamic stresses of HGPs with the misalignment errors is discussed. The result shows modification with tip relief and face-width crowning can reduce the dynamic responses caused by the impact contact of HGPs

    A study of the total chromatic number of equibipartite graphs

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    AbstractThe total chromatic number Ļ‡t(G) of a graph G is the least number of colors needed to color the vertices and edges of G so that no adjacent vertices or edges receive the same color, no incident edges receive the same color as either of the vertices it is incident with. In this paper, we obtain some results of the total chromatic number of the equibipartite graphs of order 2n with maximum degree n āˆ’ 1. As a part of our results, we disprove the biconformability conjecture

    RESEARCH ON THE MARKETING AND PUBLIC RELATIONS EFFECT AND SPORT EVENT SATISFACTION OF THE TAIPEI 2017 UNIVERSIADE

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    The purpose of this study is to investigate the spectatorsā€™ marketing and public relations and sport event satisfaction with their participation in the Taipei 2017 Universiade. Meanwhile, based on the comparison of different personal background variables, this study compares the attractiveness and satisfaction of the spectatorsā€™ marketing and public relations recognition, marketing and public relations attitude, event planning and sport event services. A random sampling method is adopted in this study. Among spectators, university students of the Taipei 2017 Universiade are selected. A total of 700 questionnaires are distributed and 680 valid questionnaires are collected. The effective recovery rate is 97.14%. The research tool of this study is ā€œSatisfaction scale of marketing and public relations effect and sport event satisfaction of the Taipei 2017 Universiadeā€. This study uses statistical methods such as descriptive statistics, independent sample t-tests, and so forth. The results of this study are: (1) In the Taipei 2017 Universiade, spectators have the highest attractiveness with ā€œInternetā€ in ā€œmedia toolsā€ of marketing and public relations recognition, followed by the factor of ā€œTVā€; (2) In ā€œmarketing and public relations attitudeā€ of the Taipei 2017 Universiade, ā€œmarketing and public relations present efforts and earnest of Taiwanā€ ranks the highest, followed by ā€œmarketing and public relations are impressedā€; (3) In ā€œsport event servicesā€ of the Taipei 2017 Universiade, ā€œauditoriumā€ ranks the highest, followed by ā€œbroadcast notificationā€; (4) There is no significant difference in the attractiveness and satisfaction among spectators with different personal background for ā€œmarketing and public relations recognitionā€, ā€œmarketing and public relations attitudeā€, and ā€œsport event servicesā€ in the Taipei 2017 Universiade.Ā  Article visualizations

    A study of the total chromatic number of equibipartite graphs

    Get PDF
    AbstractThe total chromatic number Ļ‡t(G) of a graph G is the least number of colors needed to color the vertices and edges of G so that no adjacent vertices or edges receive the same color, no incident edges receive the same color as either of the vertices it is incident with. In this paper, we obtain some results of the total chromatic number of the equibipartite graphs of order 2n with maximum degree n āˆ’ 1. As a part of our results, we disprove the biconformability conjecture
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