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Tuy Hoa, Vietnam

The Hong Duc University is a regional university located in Vietnam, belonging to the government in the province of Thanh Hoa. It offers bachelor's and master's degrees, mainly in teacher training, economics, technology and agriculture. Wikipedia.


Ou Y.-C.,National Taiwan University of Science and Technology | Ngo S.-H.,Hong Duc University
Advances in Structural Engineering | Year: 2016

Based on the actual, discrete locations of interception points between the critical shear crack and transverse reinforcement, this study developed the discrete computational shear strength models for 5-, 6-, and 11-circular-hoop and spiral reinforcement. Moreover, conventional simplified calculation method was revised for use for 5-, 6-, and 11-circular-hoop and spiral reinforcement. Examination of the difference between the discrete computational shear strength models and simplified calculation shows that the error of the simplified calculation increases with increasing ratios of spacing to diameter of circular hoops or spirals. Limiting values of spacing to diameter ratios were proposed to control the error of the simplification calculation to be equal to or less than 10%. Plots of modification factors were proposed to be used with the simplification calculation when the spacing to diameter ratio is large. © The Author(s) 2016 Reprints and permissions. Source


Karapnar E.,Atilim University | Luong N.V.,Hong Duc University
Computers and Mathematics with Applications | Year: 2012

The notion of coupled fixed point is introduced by Gnana-Bhaskar and Lakshmikantham. Very recently, the concept of tripled fixed point was introduced by Berinde and Borcut. In this manuscript, a quadruple fixed point is considered and some new related fixed point theorems are obtained. We also give some examples to illustrate our results. © 2012 Elsevier Ltd. All rights reserved. Source


Pham T.A.,Hong Duc University
Computer Communications | Year: 2011

In this paper, I propose an improvement of knapsack cipher. This improvement makes the cipher more high security and efficient. With the enhancement, the new knapsack cipher can be applied widely in the systems which need high security. © 2010 Elsevier B.V. All rights reserved. Source


Le V.B.,University of Rostock | Nguyen N.T.,Hong Duc University
Information Processing Letters | Year: 2011

The square H2 of a graph H is obtained from H by adding new edges between every two vertices having distance two in H. Lau and Corneil [Recognizing powers of proper interval, split and chordal graphs, SIAM J. Discrete Math. 18 (2004) 83-102] proved that recognizing squares of split graphs is an NP-complete problem. In contrast, we show that squares of strongly chordal split graphs can be recognized in quadratic-time by giving a structural characterization of these graph class. © 2010 Elsevier B.V. All rights reserved. Source


Farzad B.,Brock University | Lau L.C.,Chinese University of Hong Kong | Le V.B.,University of Rostock | Tuy N.N.,Hong Duc University
Algorithmica (New York) | Year: 2012

Graph G is the square of graph H if two vertices x,y have an edge in G if and only if x,y are of distance at most two in H. Given H it is easy to compute its square H 2, however Motwani and Sudan proved that it is NP-complete to determine if a given graph G is the square of some graph H (of girth 3). In this paper we consider the characterization and recognition problems of graphs that are squares of graphs of small girth, i.e. to determine if G=H 2 for some graph H of small girth. The main results are the following. There is a graph theoretical characterization for graphs that are squares of some graph of girth at least 7. A corollary is that if a graph G has a square root H of girth at least 7 then H is unique up to isomorphism. There is a polynomial time algorithm to recognize if G=H 2 for some graph H of girth at least 6. It is NP-complete to recognize if G=H 2 for some graph H of girth 4. These results almost provide a dichotomy theorem for the complexity of the recognition problem in terms of girth of the square roots. The algorithmic and graph theoretical results generalize previous results on tree square roots, and provide polynomial time algorithms to compute a graph square root of small girth if it exists. Some open questions and conjectures will also be discussed. © 2010 Springer Science+Business Media, LLC. Source

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