211 research outputs found
Wetland Habitat Studies using various Classification Techniques on Multi-Spectral Landsat Imagery: Case study: Tram chim National Park, Dong Thap Vietnam
Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial TechnologiesWetland is one of the most valuable ecological systems in nature. Wetland habitat is
a set of comprehensive information of wetland distribution, wetland habitat types are
essential to wetland management programs. Maps of wetland should provide
sufficient detail, retain an appropriate scale and be useful for further mapping and
inventory work (Queensland wetland framework).
Remotely sensed image classification techniques are useful to detect vegetation
patterns and species combination in the inaccessible regions. Automated
classification procedures are conducted to save the time of the research.
The purpose of the research was to develop a hierarchical classification approach
that effectively integrate ancillary information into the classification process and
combines ISODATA (iterative self-organizing data analysis techniques algorithm)
clustering, Maximum likelihood and rule-based classifier. The main goal was to find
out the best possible combination or sequence of classifiers for typically classifying
wetland habitat types yields higher accuracy than the existing classified wetland
map from Landsat ETM data. Three classification schemes were introduced to
delineate the wetland habitat types in the idea of comparison among the methods.
The results showed the low accuracy of different classification schemes revealing
the fact that image classification is still on the way toward a fine proper procedure to
get high accuracy result with limited effort to make the investigation on sites. Even
though the motivation of the research was to apply an appropriate procedure with
acceptable accuracy of classified map image, the results did not achieve a higher
accuracy on knowledge-based classification method as it was expected. The
possible reasons are the limitation of the image resolution, the ground truth data
requirements, and the difficulties of building the rules based on the spectral
characteristics of the objects which contain high mix of spectral similarities
HO CHI MINH’S THOUGHT ON EDUCATION AND ITS MEANING FOR HUMAN RESOURCES TRAINING TO MEET THE REQUIREMENTS OF THE FORTH INDUSTRIAL REVOLUTION
Choosing the path of proletarian revolution to liberate the nation, emancipate classes, and liberate people, Ho Chi Minh has placed top attention on changing and developing the country's education, considering it the basic foundation to change ideologies, awaken the national consciousness among the people, and make the revolution a complete success. Ho Chi Minh emphasized the role of education, considering it as one of the factors determining the success of realizing the goal of building a new Vietnam. Inheriting and applying Ho Chi Minh's thought in the cause of renewal, the Communist Party of Vietnam has always paid attention to building and developing education to meet the requirements of industrialization and modernization of the country. In the period of international economic integration, meeting the requirements of the fourth industrial revolution, the training of high-quality human resources has become even more urgent. Ho Chi Minh's thought on education has become more and more practical in training, developing and using quality human resources to serve the country's socio-economic goals, and realize the goal of "rich people, a strong country, equal, democratic and civilized society".
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Structural Control Systems in High-speed Railway Bridges
Structural vibration control of high-speed railway bridges using tuned mass dampers, semi-active tuned mass dampers, fluid viscous dampers and magnetorheological dampers to reduce resonant structural vibrations is studied. In this work, the addressed main issues include modeling of the dynamic interaction of the structures, optimization of the parameters of the dampers and comparison of their efficiency.
A new approach to optimize multiple tuned mass damper systems on an uncertain model is proposed based on the H-infinity optimization criteria and the DK iteration procedure with norm-bounded uncertainties in frequency domain. The parameters of tuned mass dampers are optimized directly and simultaneously on different modes contributing significantly to the multi-resonant peaks to explore the different possible combinations of parameters. The effectiveness of the present method is also evaluated through comparison with a previous method.
In the case of semi-active tuned mass dampers, an optimization algorithm is derived to control the magnetorheological damper in these semi-active damping systems. The use of the proposed algorithm can generate various combinations of control gains and state variables. This can lead to the improvement of the ability of MR dampers to track the desired control forces. An uncertain model to reduce detuning effects is also considered in this work.
Next, for fluid viscous dampers, in order to tune the optimal parameters of fluid viscous dampers to the vicinity of the exact values, analytical formulae which can include structural damping are developed based on the perturbation method. The proposed formulae can also be considered as an improvement of the previous analytical formulae, especially for bridge beams with large structural damping.
Finally, a new combination of magnetorheological dampers and a double-beam system to improve the performance of the primary structure vibration is proposed. An algorithm to control magnetorheological dampers in this system is developed by using standard linear matrix inequality techniques. Weight functions as a loop shaping procedure are also introduced in the feedback controllers to improve the tracking ability of magnetorheological damping forces. To this end, the effectiveness of magnetorheological dampers controlled by the proposed scheme, along with the effects of the uncertain and time-delay parameters on the models, are evaluated through numerical simulations.
Additionally, a comparison of the dampers based on their performance is also considered in this work
CHARACTERISTICS OF QUATERNARY SEDIMENTARY FACIES IN RELATION TO WATER BEARING CAPACITY OF AQUIFERS AND AQUICLUDES IN RED RIVER DELTA, VIETNAM
Joint Research on Environmental Science and Technology for the Eart
Uloga osobina ličnosti u oblikovanju poduzetničke namjere: Komparativna studija Južne Koreje i Vijetnama
This paper investigates the role of personality traits in nurturing entrepreneurial
intention in South Korea and Vietnam. We developed a research model to examine the
integrated influence of both positive entrepreneurial characteristics and dark triad on
entrepreneurial intention in South Korea and Vietnam. Primary data was collected
from 550 students in South Korea and 700 students in Vietnam using the convenient
sampling method in a self-administered questionnaire survey. We used structural
equation modelling (SEM) to analyse structural relationships between positive
entrepreneurial attributes, dark triads, and entrepreneurial intention in two samples.
T-tests were also performed to explore any differences in students’ entrepreneurial
intention in South Korea and Vietnam regarding their family background and gender.
Findings showed that positive entrepreneurial attributes and dark triads influence
entrepreneurial intention differently in the two countries. While the dark triad mainly
influenced Vietnamese students’ intention to startup, Korean students received more
impact from the positive entrepreneurial characteristics such as risk tolerance, locus
of control, and entrepreneurial alertness. Surprisingly, both gender and family
tradition do not affect students’ entrepreneurial intention. Based on our findings, we
suggested that policymakers and higher education institutions in both South Korea
and Vietnam promote students’ entrepreneurial intentions in the future.Ovaj rad istražuje ulogu osobina ličnosti u njegovanju poduzetničkih namjera u
Južnoj Koreji i Vijetnamu. Razvili smo znanstveni model za ispitivanje integriranog
utjecaja pozitivnih poduzetničkih karakteristika kao i utjecaj mračne trijade na
poduzetničke namjere u Južnoj Koreji i Vijetnamu. Primarni podaci dobiveni
anketiranjem 550 studenata u Južnoj Koreji i 700 studenata u Vijetnamu
prikupljeni su korištenjem prikladne metode uzorkovanja u anketi koju su sami
proveli. Koristili smo modeliranje strukturnim jednadžbama (SEM) za analizu
strukturnih odnosa između pozitivnih poduzetničkih atributa, tamnih trijada i
poduzetničke namjere u dva uzorka. Također su provedeni T-testovi kako bi se
istražile razlike u poduzetničkim namjerama studenata u Južnoj Koreji i Vijetnamu
s obzirom na njihovo obiteljsko porijeklo i spol. Rezultati su pokazali da pozitivne
poduzetničke osobine i mračne trijade različito utječu na poduzetničke namjere u
dvije zemlje. Dok je mračna trijada uglavnom utjecala na namjeru vijetnamskih
studenata da se pokrenu, korejski studenti dobili su veći utjecaj od pozitivnih
poduzetničkih karakteristika kao što su tolerancija na rizik, lokus kontrole i
poduzetničke budnosti. Iznenađujuće, spol i obiteljska tradicija ne utječu na
poduzetničke namjere studenata. Na temelju naših otkrića, predložili smo da
kreatori politika i visokoškolske ustanove u Južnoj Koreji i Vijetnamu promiču
poduzetničke namjere studenata u budućnosti
Investigate the Structural Response of Ultra High Performance Concrete Column under the High Explosion
Most of the structures that are damaged by an explosion are not initially designed to resist this kind of load. In the overall structure of any building, columns play an important role to prevent the collapse of frame structure under blast impact. Hence, the main concept in the blast resistance design of the structure is to improve the blast load capacity of the column. In this study, dynamic analysis and numerical model of Ultra High Performance Concrete (UHPC) column under high explosive load, is presented. Based on the Johnson Holmquist 2 damage model and the subroutine in the ABAQUS platform, a total of twenty UHPC model of the column were calculated. The objective of the article is to investigate the structural response of the UHPC column and locate the most vulnerable scenarios to propose necessary recommendations for the UHPC column in the blast loading resistance design. The input parameters, including the effect of various shapes of cross-section, scaled distance, steel reinforcement ratio, and cross-section area, are analyzed to clarify the dynamic behavior of the UHPC column subjected to blast loading. Details of the numerical data, and the discussion on the important obtained results, are also provided in this paper
After-Fatigue Condition: A Novel Analysis Based on Surface EMG Signals
This study introduces a novel muscle activation analysis based on surface
electromyography (sEMG) signals to assess the muscle's after-fatigue condition.
Previous studies have mainly focused on the before-fatigue and fatigue
conditions. However, a comprehensive analysis of the after-fatigue condition
has been overlooked. The proposed method analyzes muscle fatigue indicators at
various maximal voluntary contraction (MVC) levels to compare the
before-fatigue, fatigue, and after-fatigue conditions using amplitude-based,
spectral-based, and muscle fiber conduction velocity (CV) parameters. In
addition, the contraction time of each MVC level is also analyzed with the same
indicators. The results show that in the after-fatigue condition, the muscle
activation changes significantly in the ways such as higher CV, power spectral
density shifting to the right, and longer contraction time until exhaustion
compared to the before-fatigue and fatigue conditions. The results can provide
a comprehensive and objective evaluation of muscle fatigue and recovery, which
can be helpful in clinical diagnosis, rehabilitation, and sports performance
Biocontrol of Alternaria alternata YZU, a causal of stem end rot disease on pitaya, with soil phosphate solubilizing bacteria
Stem end rot is the most destructive disease caused by Alternaria alternata YZU in pitaya-growing regions of Vietnam. This study was conducted to characterize antagonistic phosphate-solubilizing bacteria (PSB) from rhizosphere soil for their biocontrol activities against A. alternata YZU and evaluate the effect of temperature, pH, and water activity on that antagonism. Among seven PSB isolated from 45 rhizosphere soil samples, PSB31 (identified as Bacillus sp. strain IMAU61039, Accession number: MF803700.1) exhibited the highest antagonistic activity against A. alternata YZU with an average inhibition diameter of 0.65 ± 0.05 cm. The results also show that the strain PSB31 controlled the mycelial growth of A. alternata YZU by secreting antifungal metabolites. The most potent inhibitory activity was identified under in vitro conditions of 25 °C, pH 7, and aw 1. The isolated PSB31 could be a potential biological control agent against A. alternata YZU
Temperature distribution in concrete structure under the action of fire using Ansys software
In the last few decades, fires caused serious damage in civil engineering, especially in the high-rise building, factories, offices, etc. Usually the structures are built with fireproof materials such as concrete. It is a complex material, and its properties can change dramatically when exposed to high temperatures. This problem requires engineers to study and evaluate the effect of the fire in the structure. This paper studies the effect of the fire on the temperature distribution in concrete structure using Finite Element Ansys software. The results will be used to provide reference data for concrete structures under the action of fire. The research is an intermediate task to convert the fire activity in a structural model into the real impact in calculating model. It plays significant role in calculating structural model for counteracting the action of fire
Influence of Energy and Duration of Laser Pulses on Stability of Dielectric Nanoparticles in Optical Trap
In this article the gradient force of optical trap using two counter-propagating pulsed Gaussian beam and the Brownian motion in optical force field are investigated. The influence of the energy and duration time of optical pulsed Gaussian beams on satability of nano-particle in trap is simulated and discussed
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