AN ASSESSMENT OF POTENTIAL CLIMATE CHANGE IMPACTS ON FLOOD RISK IN CENTRAL VIETNAM

Flood is a natural feature of the environment and is also one the most frequent hazardous natural disaster. The impacts of flood are highly devastating and usually causing economic depression and direct damages to the livelihood, properties, and lives of the people. In recent years, the extended flat territory along the long coastline with the tropical cyclone frequency is result of flood problem in the central region of Vietnam. In an attempt to deal with this adversity, this paper aims to manifest the feasibility of assessing flood simulations that corresponds to the impacts of climate change. The system was developed using the outputs of the Hadley Centre Coupled Model, version 3 (HadCM3) for A2 and B2 scenarios and a coupling of hydrological – hydrodynamic models. The results indicated that the weather will become hotter in the future with the increase of temperature between 0.4°C to 2.2°C and 0.19°C to 0.6°C under A2 and B2 scenarios, respectively. On the other hand, the annual rainfall will also increase between 3.3% to 14.5% and 3.6% to 6.8% under A2 and B2 scenarios, respectively. The results also demonstrated that potentially serious increases in runoff and water level under future climate change scenarios. The unanticipated consequences might play a large role in destruction of crops, transportation, water supply, and communities located in the Huong River Basin. Additionally, the outcomes of this study can be applied for the entire Huong River Basin in order to mitigate the flood problems in the future

Spintronique, de la magnétorésistance géante aux Skyrmions magnétiques et isolants topologiques

International audienceThis article aims at giving a general presentation of spintronics, an important field of research developing today along many new directions in physics of condensed matter. We tried to present simply the physical phenomena involved in spintronics – no equations but many schematics. We also described the applications of spintronics, those of today and those expected to have an important impact on the next developments of the information and communication technologies.Cet article se veut une présentation générale de la spintronique. C’est aujourd’hui un important domaine de recherche qui se développe sur de nombreux nouveaux axes de la physique de la matière condensée. Nous avons voulu présenter simplement les phénomènes physiques impliqués dans la spintronique – sans équations mais avec de nombreux schémas. Nous décrivons aussi les applications de la spintronique, celles d’aujourd’hui et celles dont l’on attend un impact important sur les prochains développements des technologies de l’information et de la communication

Augmented Linear Inverted Pendulum Model for Bipedal Gait Planning

Ph.DDOCTOR OF PHILOSOPH

Soft ionic liquid multi-point touch sensor

The development of electronic skin (e-skin) and soft tactile sensing has recently attracted great interest. Here we report for the first time on a novel ionic liquid (IL) based soft pressure sensor with multi-point touch detection capability using 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]+[BF4]−) as a highly conductive sensing medium. The sensing mechanism is attributed to the repopulation of charge cations and anions in aqueous solution under pressure. The sensor can detect two dimensional touching positions with a sensitivity of −0.28% kPa−1. Our sensor showed good stability and temperature independence thanks to the incompressibility of IL in the range of touch pressure and the appropriate signal measurement configuration. We successfully demonstrated the sensor's capability to detect multi-point human touch with different pressure levels. Our simple design with smart structures and ease of fabrication processes enable the development of a soft and low-cost sensor with multiple-point sensing capabilities on a single chip

Vortex flow generator utilizing synthetic jets by diaphragm vibration

This paper develops a millimeter scale fully packaged device in which a vortex flow of high velocity is generated inside a chamber. Under the actuation by a lead zirconate titanate (PZT) diaphragm, a flow circulates with increasing velocity after each actuating circle to form a vortex in a cavity named as the vortex chamber. At each cycle, the vibration of the PZT diaphragm creates a small net air flow through a rectifying nozzle, generates a synthetic jet which propagates by a gradual circulation toward the vortex chamber and then backward the feedback chamber. The design of such device is firstly conducted by a numerical analysis whose results are considered as the base of our experimental set-up. A vortex flow generated in the votex chamber was observed by a high-speed camera. The present approach which was illustrated by both the simulation and experiment is potential in various applications related to the inertial sensing, fluidic amplifier and micro/nano particle trapping and mixing

Rubber Impact on 3D Textile Composites

A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools

Spintronics, from giant magnetoresistance to magnetic skyrmions and topological insulators

This article aims at giving a general presentation of spintronics, an important field of research developing today along many new directions in physics of condensed matter. We tried to present simply the physical phenomena involved in spintronics -- no equations but many schematics. We also described the applications of spintronics, those of today and those expected to have an important impact on the next developments of the information and communication technologies

Apply deep learning to improve the question analysis model in the Vietnamese question answering system

Question answering (QA) system nowadays is quite popular for automated answering purposes, the meaning analysis of the question plays an important role, directly affecting the accuracy of the system. In this article, we propose an improvement for question-answering models by adding more specific question analysis steps, including contextual characteristic analysis, pos-tag analysis, and question-type analysis built on deep learning network architecture. Weights of extracted words through question analysis steps are combined with the best matching 25 (BM25) algorithm to find the best relevant paragraph of text and incorporated into the QA model to find the best and least noisy answer. The dataset for the question analysis step consists of 19,339 labeled questions covering a variety of topics. Results of the question analysis model are combined to train the question-answering model on the data set related to the learning regulations of Industrial University of Ho Chi Minh City. It includes 17,405 pairs of questions and answers for the training set and 1,600 pairs for the test set, where the robustly optimized BERT pre-training approach (RoBERTa) model has an F1-score accuracy of 74%. The model has improved significantly. For long and complex questions, the mode has extracted weights and correctly provided answers based on the question’s contents