Le Qui Don Technical University

Qui Nhon, Vietnam

Le Qui Don Technical University

Qui Nhon, Vietnam
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Binh D.V.,Military Information Technology Institute | Minh N.H.,Le Qui Don Technical University | Moldovyan N.A.,Russian Academy of Sciences
International Conference on Advanced Technologies for Communications | Year: 2015

The article describes a collective digital signature protocol based on the difficulty of the discrete logarithm problem modulo a composite number that is a product of two strong primes having the 2 1 size ratio. The usage of difficult problems provide signature protocol with security improvement, because the probability to break the protocol has been reduced significant. This can be achieved due to the appearance of breakthrough solutions in the area of the factoring problem and the discrete logarithm modulo a prime problem. One of the features of the protocol is using the non-cyclic finite group. After selecting appropriate parameters which provide 80-bit security, the size of the proposed collectively signature is 240 bits and is not dependent on the number of signers. © 2014 IEEE.

Tan T.D.,University of Engineering and Technology | Anh N.T.,Le Qui Don Technical University | Anh G.Q.,Namdinh University of Technology Education
Proceedings - 2011 2nd International Conference on Intelligent Systems, Modelling and Simulation, ISMS 2011 | Year: 2011

Vibration analysis is the great need and can be used in many practical applications, especially in monitoring the status of machines, bridges and other construction works. This paper presents a low-cost structural health monitoring scheme using MEMS-based accelerometers. The purpose of this scheme is to achieve the high performance system for bridge monitoring with low cost. The system can operate in two modes, real-time and offline. In the real-time mode, embedded real-time short-time Fourier transform programs on the 3-DOF accelerometers were performed for the monitoring and alert. In the offline mode, the analysis of bridge models was utilized based on DIAMOND tool for further analyses and evaluations. Initial results show that the system is suitable for practical applications. © 2011 IEEE.

Park D.E.,Inha University | Choi H.J.,Inha University | Manh Vu C.,Le Qui Don Technical University
Smart Materials and Structures | Year: 2016

Silica/polyaniline (PANI) core-shell structured microspheres were synthesized by coating the surface of silica micro-beads with PANI and applied as a candidate inorganic/polymer composite electrorheological (ER) material. The silica micro-beads were initially modified using N-[(3-trimethoxysilyl)-propyl] aniline to activate an aniline functional group on the silica surface for a better PANI coating. The morphology of the PANI coating on the silica surface was examined by scanning electron microscopy and the silica/PANI core-shell structure was confirmed by transmission electron microscopy. The chemical structure of the particles was confirmed by Fourier transform infrared spectroscopy. Rotational rheometry was performed to confirm the difference in the ER properties between pure silica and silica/PANI microsphere-based ER fluids when dispersed in silicone oil. © 2016 IOP Publishing Ltd.

Vu C.M.,Le Qui Don Technical University | Vu H.T.,AQP research and control pharmaceuticals Joint Stock Company AQP Pharma J.S.C | Choi H.J.,Inha University
Macromolecular Research | Year: 2015

Epoxidized natural rubber (ENR) was initially prepared from an in situ performic acid epoxidation reaction with 46.09 mol% epoxide groups, and the curing characteristics of the ENR/natural rubber (NR) blend with different blend ratios of ENR were studied using a Monsanto moving die rheometer. The mechanical properties of the blends, such as the tensile strength, modulus at 300% elongation and elongation at break, were also examined. The tensile strength and 300% modulus decreased with increasing ENR content and the elongation at break increased steadily with increasing ENR content. In addition, the scorch time, cure time, maximum torque and torque difference decreased with increasing ENR content. Scanning electron microscopy (SEM) of the tensile fracture surfaces of the rubber blend samples revealed better compatibility between NR and ENR with lower ENR contents. Nanocomposites based on NR/ENR blends with two different ratios, 100/0 and 80/10, reinforced with 10 phr nanosilica were also prepared to examine the effects of ENR on the mechanical properties and morphology of the nanocomposites. SEM showed that ENR assists in the dispersion of nanosilica in the NR matrix, resulting in improved mechanical properties of the nanocomposite.[Figure not available: see fulltext.] © 2015, The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht.

Vu C.M.,Le Qui Don Technical University | Choi H.J.,Inha University
Polymer Science - Series A | Year: 2016

Two kinds of micro/nano sized fibrils based on cellulose (MFC) and polyvinyl alcohol (PVA) were used as reinforcer for epoxy resin (EP) with different contents in the range from 0 to 0.3 wt %. PVA nanofibers with diameter about 40–80 nm were fabricated by electrospinning technique. The analysis of mechanical properties showed that by both adding MFC and PVA to EP the fracture toughness was increased. The SEM results showed that micro/nano sized fibers dispersed throughout epoxy resin, prevented and changed the path of crack growth. © 2016 Pleiades Publishing, Ltd.

Manh C.V.,Le Qui Don Technical University | Choi H.J.,Inha University
Polymer - Plastics Technology and Engineering | Year: 2016

In this article, the effect of silk fibroin nanofibers as a toughening agent of carbon fiber/fabric-reinforced epoxy composites is experimentally investigated. The composites showed up to 30% improvement in Mode II fracture toughness at 0.1 wt% of silk fibroin nanofibers content. The scanning electron microscopy observation revealed that the fracture surface of silk fibroin nanofibers modified carbon fiber/fabric-reinforced epoxy composites appearance of the broken fiber and the ductile-like matrix cracks showed a good adhesion between matrix resin and carbon fibers, which are reasons for the enhanced mode II interlaminar fracture toughness. © 2016, Copyright © Taylor & Francis Group, LLC.

Nguyen V.Q.,Le Qui Don Technical University | Merifield R.S.,Le Qui Don Technical University
Australian Geomechanics Journal | Year: 2012

The ability to predict the ultimate bearing capacity of a foundation is one of the most important problems in foundation engineering. To solve this problem, geotechnical engineers routinely use a bearing capacity equation that contains a number of empirical factors to account for foundation shape, depth and inclination. In this paper finite element analysis is used to predict the undrained bearing capacity of strip, square, rectangular and circular footings embedded in clay. From these analyses, rigorous shape and depth factors have been derived and are compared with previous numerical and empirical solutions in the literature. The bearing capacity behaviour is discussed and the bearing capacity factors are given for various cases involving a range of embedment depths and footing shapes.

Nguyen T.-N.,Le Qui Don Technical University | Nguyen Q.-B.,Le Qui Don Technical University | Thanh-Nguyen,Le Qui Don Technical University
ACM International Conference Proceeding Series | Year: 2015

Being robust to nonlinear distortion by owning a lower peak to average power ratio in comparision with QAM signal, APSK was recommended for using in the digital satellite video broadcasting, second generation (DVB-S2). However, the adverse effects of nonlinearity could still be reduced by redistributing signal points in the constellation. In this paper, we propose a new signal set and the mapping for the APSK signal conforming to the DVB-S2 standard at high nonlinearity level. Moreover, this new proposed APSK signal further improves the performance of HPA in terms of power efficiency. © 2015 ACM.

Tan T.D.,University of Engineering and Technology | Anh N.T.,Le Qui Don Technical University
Proceedings - 2011 2nd International Conference on Intelligent Systems, Modelling and Simulation, ISMS 2011 | Year: 2011

A three-axis piezoresistive accelerometer which has uniform sensitivities to three axes was developed using MicroElectroMechanical Systems (MEMS) technology. This sensor which is made of a heavy proof mass and four long beams allow us to obtain high sensitivities by reducing the resonant frequencies. Uniform axial sensitivities with small cross axis sensitivity could be obtained by a three-dimensional sensor structure. © 2011 IEEE.

Thi B.D.,Thai Nguyen University | Hieu M.N.,Le Qui Don Technical University
International Journal of Security and its Applications | Year: 2013

The Block cipher BM-128 which is proved to be suitable to the applications in the wireless communication systems are proposed in this paper. It is developed based on SDDO which is constructed from CSPN. BM-128 also eliminates the weak keys without the complex round key proceduce and meet the requirements of NESSIE. Design shall meet all the security requirements to protect applications against the well-known threats. In addition, BM-128 evaluated to have higher performance than the other algorithms when they are used in cheap hardware. © 2013 SERSC.

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