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Van Son P.,University of Tsukuba | Van Son P.,Danang University of Education | Fujitsuka A.,University of Tsukuba | Ohshima K.-I.,University of Tsukuba
Journal of Electronic Materials | Year: 2012

In an effort to improve the performance of lead-free solder, Sn-3.5 wt.%Ag (Sn-3.5Ag) solder alloy with 0.03 wt.% carbon black was prepared under high pressure (5.5 GPa) and high temperature (1200°C). We have investigated the microstructure, melting behavior, and mechanical properties of the alloy using x-ray diffraction, differential scanning calorimetry (DSC), Vickers hardness testing, tensile testing, and scanning electron microscopy (SEM). The melting point was found to be unchanged, while the hardness and the tensile strength increased with the addition of carbon black. SEM images showed that the average thickness of the intermetallic compound (IMC) layer decreased with the addition of carbon black, indicating improvement in solder joint reliability. © 2012 TMS. Source

Pham N.M.N.,Vietnam Korea Friendship information technology College | Nguyen T.H.,Vietnam Korea Friendship information technology College | Le V.S.,Danang University of Education
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Nowadays, one of the issues in cloud computing is resource optimizing for virtual services to enhance IaaS service performance and meet the requirements of resource exploitation effectively. In this paper, we seek the approach of multi-dimensional resource allocation based on heterogeneous shared hosting platforms for virtual services. We construct the problem as an optimized formulation that uses a linear programming to minimize the number of physical machines. The solution for this formulation is applying the Greedy algorithms to solve and evaluate via emulation-based program. © Springer-Verlag Berlin Heidelberg 2016. Source

Nguyen H.H.C.,Quangnam University | Le D.-N.,Haiphong University | Le V.S.,Danang University of Education | Thuy N.T.,Hanoi University of Science and Technology
Frontiers in Artificial Intelligence and Applications | Year: 2015

An allocation of resources to a virtual machine specifies the maximum amount of each individual element of each resource type that will be utilized, as well as the aggregate amount of each resource of each type. In this paper, we present an new approach to improve the deadlock detection algorithm, to schedule the policies of resource supply for allocating multiple resources to competing services running in virtual machines on a heterogeneous distributed platform. We introduce the matrix representation of a deadlock detection problem and some essential features can be mapped into a cloud architecture which can handle multiple requests/grants simultaneously and can detect multiple deadlocks in linear time, hence, significantly improving performance. Our algorithm proposed has a run time complexity of O(min(m,n)), where m is the number of resources and n is the number of processes. The experiments also compare the performance of our algorithm proposed approach with other related works. Source

Hong T.T.,Danang University of Education | Dung P.T.,Vietnam Academy of Science and Technology | Quang V.X.,Duy Tan University
Journal of Electronic Materials | Year: 2016

Tellurite glass doped with different concentrations of Eu3+ ions has been prepared by the conventional melting process. Photoluminescence, Raman spectra, phonon side-band spectra, and Judd–Ofelt analysis were carried out. Some spectroscopic parameters were estimated to predict the luminescence efficiency of the materials. The energy transfer between the rare-earth ions was observed, and a model for its cross-relaxation was proposed and quantitatively estimated. The charged intrinsic defects in the form of nonbridging oxygen (NBO) were determined, and the energy transfer between NBO and rare-earth ions observed. The energy-transfer-induced Eu3+ photoluminescence enhancement in tellurite glass is studied. © 2016 The Minerals, Metals & Materials Society Source

Quoc C.T.,Danang University of Education
Proceedings of the 2013 13th International Conference on Computational Science and Its Applications, ICCSA 2013 | Year: 2013

The problem of finding maximum flow in network graph is extremely interesting and practically applicable in many fields in our daily life, especially in transportation. Therefore, a lot of researchers have been studying this problem in various methods. In this paper, we offer a different method to solve this problem that is the postflow-pull method with complexity equal to complexity used pre-flow push by A. Goldberg and R.E. Tarjan 1986. In addition, to take more advantage of multi-core architecture of the parallel computing system, we build this algorithm on multiple processors. This is a completely new method not being announced in the world. The results of this paper are basically systematized and proven. The idea of this algorithm is using multi processors to work in parallel by postflow-pull alogrithm. Among these processors, there is one main processor managing data, sending data to the sub processors, receiving data from the sub-processors. The sub-processors simultaneously execute their work and send their data to the main processor until the job is finished, the main processor will show the results of the problem. © 2013 IEEE. Source

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