oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 12 )

2019 ( 175 )

2018 ( 212 )

2017 ( 204 )

Custom range...

Search Results: 1 - 10 of 134909 matches for " Thanh V Nguyen "
All listed articles are free for downloading (OA Articles)
Page 1 /134909
Display every page Item
Fitting a Probability Distribution to Extreme Precipitation for a Limited Mountain Area in Vietnam  [PDF]
Nguyen Tien Thanh
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.55007
Abstract: In this paper, an analysis of adapted 20 extreme precipitation indices is calculated for a limited mountain area in southern Vietnam. The daily precipitation data from four stations in the period of more than 30 years are selected. The statistical characteristics of maximum, minimum, mean, standard deviation, skewness, and kurtoris for each index are also analysed. A variety of distributions such as Normal, Lognormal, Beta, Gamma, Exponential, Loglogistic, and Johnson is used to find the best fit probability distribution for this area on the basic of the highest score. The scores are estimated based on the ranking of statistical goodness of fit test. The goodness of fit tests is the Anderson-Darling and Shapiro-Wilks tests. The best fit distribution for each index of extreme precipitation at each station is found out. Results revealed that the Johnson distribution is the best fit distribution to the data of very heavy precipitation days greater than 50 mm. Over a limited mountain area, it is difficult to fit a probability distribution to the precipitation fraction due to extremely wet days, number of extremely wet days, and number of extremely wet days when precipitation greater than 99 percentage. The lognormal, Johnson, and Loglogistic distribution are the best choices to fit most of the extreme precipitation indices over this area.
Modeling Election Problem by a Stochastic Differential Equation  [PDF]
Nguyen Thanh Trung
American Journal of Operations Research (AJOR) , 2018, DOI: 10.4236/ajor.2018.86024
Abstract: The proportion of the favorable among voters to a nominee might change over times and depend on different factors for example: talent, reputation, party and even name order on election. The unobservable factors which might have minor impacts on the approval rate are modelized by random elements. The approval rate is initially described by the differential equation and then by the random differential equation including the above unobservable factors. We figure out the formula of the solution for the stochastic differential equation and simulate these solutions to identify the changes of the approval rate over time.
A New Model for the Collective Behavior of Animals
P. The Nguyen,V. Thanh Ngo,H. T. Diep
Physics , 2015,
Abstract: We propose a new model in order to study behaviors of self-organized system such as a group of animals. We assume that the individuals have two degrees of freedom corresponding one to their internal state and the other to their external state. The external state is characterized by its moving orientation. The rule of the interaction between the individuals is determined by the internal state which can be either in the non-excited state or in the excited state. The system is put under a source of external perturbation called "noise". To study the behavior of the model with varying noise, we use the Monte-Carlo simulation technique. The result clearly shows two first-order transitions separating the system into three phases: with increasing noise, the system undergoes a phase transition from a dilute disordered phase to an ordered compact phase and then to the disordered dispersed phase. These phases correspond to behaviors of animals: uncollected state at low noise, flocking at medium noise and runaway at high noise, respectively.
Effect of Vision Angle on the Phase Transition in a Flocking Behavior of Animal Groups
P. The Nguyen,Sang-Hee Lee,V. Thanh Ngo
Quantitative Biology , 2014, DOI: 10.1103/PhysRevE.92.032716
Abstract: The nature of the phase transition in a system of self-propelling particles has been extensively studied during the last few decades. A theoretical model was proposed by T. Vicsek, {\it et. al.} [Phys. Rev. Lett. {\bf 75}, 1226 (1995)] with a simple rule for updating the direction of motion of each particle. Based on the Vicsek's model (VM) [1], in this work, we consider a group of animals as particles moving freely on a two-dimensional space. Due to the fact that the viewable area of animals depends on the species, we consider the motion of each individual within an angle $\varphi=\Phi/2$ ($\Phi$ is called angle of view) of a circle centered at its position, of radius $R$. We obtained a phase diagram in the space ($\varphi$, $\eta_c$) with $\eta_c$ being the critical noise. We show that, the phase transition exists only in the case of a wide view's angle $\varphi \geq 0.5\pi$. The flocking of animals is an universal behavior of the species of prey, but not the one of the predator. Our simulation results are in good agreement with experimental observation [2].
Assessment of Post-Laparoscopic Cholecystectomy Pain at Viet Duc Hospital, Vietnam  [PDF]
Dan Thi Nguyen, Huong Thi Thanh Nguyen
Health (Health) , 2015, DOI: 10.4236/health.2015.73039
Abstract: Gallstones are common and costly in the world. This disease also have high health burden with high mortality. Currently, Laparoscopic Cholecystectomy has become a gold standard for surgical treatment of symptomatic gallstones. Pain is usually the first concern after surgery. Postoperative pain decreases with time but it is severe enough to interfere with daily activities of patients. Pain after the surgery is also affected by many factors. This cross-sectional study aimed to 1) assess pain intensity and interference pain with daily activities; 2) describe the association between pain intensity and interference with daily activities of patients; 3) explore factors that influence post-operative pain after Laparoscopic Cholecystectomy. Data were collected by 50 patients who were undergoing Laparoscopic Cholecystectomy completed questionnaire including the Visual Analogue Scale (VAS) and the Brief Pain Inventory (BPI). Data were analyzed based on three aims. As this is the first time that this type of study is conducted in Vietnam, it is expected that the results will contribute significantly to local knowledge and should add to global perspectives. From understanding the factors that affect severity of pain, this study is expected to design nursing intervention strategies to improve daily activities among patients undergoing LC.
Impacts of Socio-culture on the development of autonomous learning: A lens of Vietnamese context
Thanh Nguyen
Journal of Studies in Education , 2011, DOI: 10.5296/jse.v1i1.866
Abstract: The paper examines the influences of socio-culture on the development of autonomous learning of Vietnamese students. This study was documented from a number of researchers who have devoted their research on autonomous learning and it’s conjunction with native social-cultural influences. The key focus of the paper is to identify how socio-cultural factors impact on student’s autonomous learning in Vietnam. The results are important as they bring the researcher a review for a further study.
Contact with Biological Parents for Children in Residental Care: A Vietnam Study  [PDF]
Nguyen Ba Dat, Nguyen Van Luot, Nguyen Ha Thanh
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.611021
Abstract: Children living in residential care have a degree of separation from their parents and other family members. Based on attachment theory, this study was conducted to analyze the contact between these children and their biological parents, and the factors affecting this contact. The sample included 382 children (orphans, abandoned or helpless children, children whose parents are deprived of custody or are unable to raise a child) living in residential centers located in North, Central and South of Vietnam. Data were obtained by semi-structured interviews. The results showed that, on average, children contact their parents and family members once a month. In addition, variables such as family image in children’s mind and joyfulness when meeting parents are the best predictors of contact between children and parents, family members. The contact between children and parents is arguably considered as a form of consolidation and maintenance of emotional relationship.
The MB2 gene family of Plasmodium species has a unique combination of S1 and GTP-binding domains
Lisa C Romero, Thanh V Nguyen, Benoit Deville, Oluwasanmi Ogunjumo, Anthony A James
BMC Bioinformatics , 2004, DOI: 10.1186/1471-2105-5-83
Abstract: Genes homologous to MB2 were identified in five additional parasite species, P. knowlesi, P. gallinaceum, P. berghei, P. yoelii, and P. chabaudi. Sequence comparisons among the MB2 gene products reveal amino acid conservation of structural features, including putative S1 and GTP-binding domains, and putative signal peptides and nuclear localization signals.The combination of domains is unique to this gene family and indicates that MB2 genes comprise a novel family and therefore may be a good target for drug development.Malaria causes 300–500 million clinical cases and more than one million deaths world-wide each year [1]. Efforts to reduce disease that rely on chemotherapeutics and insecticides are undermined by an increase in drug and insecticide resistance. Development of new control mechanisms is facilitated by an understanding of basic Plasmodium biology, and the identification of unique and vulnerable properties that can be exploited by therapeutics, vaccines or other control strategies. However, in spite of more than a century of malaria research, much is still unknown about the biology of Plasmodium parasites due in large part to the extraordinary complexity of their life cycles. These parasites are able to infect vertebrate and invertebrate hosts, survive in intracellular and extracellular environments, invade multiple types of cells, and evade the immune responses of both hosts. At each stage of the life cycle, new sets or combinations of proteins are expressed, therefore the biology of the parasite is continually changing. The uniqueness and complexity of this parasite is underscored by the revelation that approximately two-thirds of the P. falciparum open reading frames (ORFs) predicted from the recently completed genome sequence do not match proteins in existing databases [2]. This finding presents a unique opportunity to identify and characterize novel Plasmodium proteins that may be exploited for therapeutic benefits.The P. falciparum gene, MB2, is a s
Modeling and Adaptive Self-Tuning MVC Control of PAM Manipulator Using Online Observer Optimized with Modified Genetic Algorithm  [PDF]
Ho Pham Huy Anh, Nguyen Thanh Nam
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.32016
Abstract: In this paper, the application of modified genetic algorithms (MGA) in the optimization of the ARX Model-based observer of the Pneumatic Artificial Muscle (PAM) manipulator is investigated. The new MGA algorithm is proposed from the genetic algorithm with important additional strategies, and consequently yields a faster convergence and a more accurate search. Firstly, MGA-based identification method is used to identify the parameters of the nonlinear PAM manipulator described by an ARX model in the presence of white noise and this result will be validated by MGA and compared with the simple genetic algorithm (GA) and LMS (Least mean-squares) method. Secondly, the intrinsic features of the hysteresis as well as other nonlinear disturbances existing intuitively in the PAM system are estimated online by a Modified Recursive Least Square (MRLS) method in identification experiment. Finally, a highly efficient self-tuning control algorithm Minimum Variance Control (MVC) is taken for tracking the joint angle position trajectory of this PAM manipulator. Experiment results are included to demonstrate the excellent performance of the MGA algorithm in the NARX model-based MVC control system of the PAM system. These results can be applied to model, identify and control other highly nonlinear systems as well.
Effect of Melt Mixing Time in Internal Mixer on Mechanical Properties and Crystallization Behavior of Glycidyl Methacrylate Grafted Poly (Lactic Acid)  [PDF]
Nguyen Chi Thanh, Chaiwat Ruksakulpiwat, Yupaporn Ruksakulpiwat
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.37013
Abstract:

Glycidyl methacrylate (GMA) was grafted onto poly (lactic acid) (PLA) by melt mixing in internal mixer using dicumyl peroxide (DCP) as an initiator. The results from proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectroscopy indicated that the grafting reaction of GMA onto PLA took place successfully. The impact strength of PLA-g-GMA was significantly higher than that of pure PLA. The crystallinity of PLA, obtained from differential scanning calorimetry (DSC), decreased after grafting. In order to obtain the optimal mixing conditions, the mixing time was varied into 7, 10 and 14 min. The optimum mixing time of 10 min was found to give the optimum mechanical properties of glycidyl methacrylate grafted poly (lactic acid) (PLA-g- GMA). However, the mixing time played no important role in impact behavior of PLA-g-GMA. In addition, the highest crystallinity was obtained with the PLA-g-GMA prepared with the mixing time of 7 min.

Page 1 /134909
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.