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Results 311-320 of 691 (Search time: 0.001 seconds).
  • Authors: Nguyen Van Duy; Nguyen, Xuan Thai; Trinh, Minh Ngoc;  Advisor: -;  Co-Author: - (2022)

    Classification of different gases is important, and it is possible to use different gas sensors for this purpose. Electronic noses, for example, combine separated gas sensors into an array for detecting different gases. However, the use of separated sensors in an array suffers from being bulky, high-energy consumption and complex fabrication processes. Generally, gas sensing properties, including gas selectivity, of semiconductor gas sensors are strongly dependent on their working temperature

  • Authors: Ngo, Dinh Dat; Tran, Quoc Quan; Nguyen, Dinh Duc;  Advisor: -;  Co-Author: - (2022)

    Mathematic modeling and analytical approach are presented for nonlinear vibration analysis of laminated plate with auxetic honeycomb core and magneto-electro-elastic face sheets supported by Pasternak-type elastic foundations. The laminated plate is subjected to the simultaneous action of blast, thermal, electric and magnetic loadings. The mechanical properties of auxetic core including negative Poisson’s ratio are assumed to depend on the geometrical parameters of the unit cells and elastic modulus of original material. The volume fraction of two components of each magneto-electro-elastic face sheet is chosen equally.

  • Authors: Quan, Hoang Vuong; Hiep, Hung Pham; Dong, Thi Kieu Trang; Ho, Manh Toan; Dinh, Viet Hung;  Advisor: -;  Co-Author: - (2021)

    By reviewing regulative documents and extant literature, this paper explores the realities and trends of international students in East and Southeast Asia (ESA). It also shows motivation and strategies of four new players in the international higher education sector in East and Southeast Asia i.e., China, Hong Kong, Taiwan and Malaysia. Apart from showing that intraregional students have not predominated the overall international student population in the region anymore, the paper highlights that ESA region has become an established hub of international students rather than a new emerging destination as it was in previous years. The overall net flow of international students in this region was still deficit prior to 2010s, but the deficit in 2017 is still less than that of 2010’s. T...

  • Authors: Thuy Anh Ta; Tien Mai; Fabian Bastin; Pierre L’Ecuyer;  Advisor: -;  Co-Author: - (2021)

    We consider a multistage stochastic discrete program in which constraints on any stage might involve expectations that cannot be computed easily and are approximated by simulation. We study a sample average approximation (SAA) approach that uses nested sampling, in which at each stage, a number of scenarios are examined and a number of simulation replications are performed for each scenario to estimate the next-stage constraints. This approach provides an approximate solution to the multistage problem. To establish the consistency of the SAA approach, we first consider a two-stage problem and show that in the second-stage problem, given a scenario, the optimal values and solutions of the SAA converge to those of the true problem with probability one when the sample sizes go to infin...

  • Authors: Xianyu, Jianga; Weihong, Wana; Bo, Wang;  Advisor: -;  Co-Author: - (2021)

    Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coati...

  • Authors: Xianyu, Jianga; Weihong, Wana; Bo, Wang;  Advisor: -;  Co-Author: - (2022)

    Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol–gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73° hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coati...

  • Authors: Trung Thanh, Nguyen; Khaled, Elbassioni; Nguyen, Cong Luong;  Advisor: -;  Co-Author: - (2022)

    In this paper, we consider a distributed joint sensing and communication (DJSC) system in which each radar sensor as a JSC node is equipped with a sensing function and a communication function. Deploying multiple JSC nodes may require a large amount of bandwidth. Therefore, we investigate the bandwidth allocation problem for the DJSC system. In particular, we aim to optimize the bandwidth allocation to the sensing function and the communication function of the JSC nodes. To improve the allocation efficiency while benefiting the spatial diversity advantage of the DJSC systems, the objective is to maximize the sum of sensing performances, i.e., estimation rates, communication performances, i.e., communication data rates, and fairness of all the users. The optimization problem is non-c...

  • Authors: Quy Van, Khuc; Duy, Nong; Tri Phu, Vu;  Advisor: -;  Co-Author: - (2022)

    This paper aims to investigate the air pollution issues in Hanoi – one of the most air polluted cities in the world in recent years – on residents’ and foreign visitors’ perceptions and how their trust in the local government to establish a joint funding mechanism to mitigate air pollution in Hanoi. Such information is fundamental in order to establish an effective and efficient program to improve air quality not only in Hanoi, but also in many cities around the world. We employ a random stratified approach coupled with the contingent valuation survey and an interval regression model over a sample of 475 residents and 75 foreigners.