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Search Results: 1 - 10 of 20163 matches for " Le Nguyen Hoa "
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A Novel Stochastic-Based Algorithm for Terrain Splitting Optimization Problem
Le Hoang Son,Nguyen Dinh Hoa
International Journal of Soft Computing & Engineering , 2013,
Abstract: This paper deals with the problem of displayinglarge Digital Elevation Model data in 3D GIS. Currentapproaches relate to the splitting algorithms by 2D PolygonalVector Data such as Particle Swarm Optimization (PSO-TSA) andGenetic Algorithm (GA-TSA). We will, herein, present anothermethod based on stochastic optimization for the consideredproblem. It also employs some ideas of Wife-Selection scenarioand Stick Procedure. The new method allows us to quickly findthe optimal saving threshold. The comparison with thestate-of-the-art method will be made to verify the efficiency of theproposed method.
Object-Based vs. Pixel-Based Classification of Mangrove Forest Mapping in Vien An Dong Commune, Ngoc Hien District, Ca Mau Province Using VNREDSat-1 Images  [PDF]
Nguyen Thi Quynh Trang, Le Quang Toan, Tong Thi Huyen Ai, Nguyen Vu Giang, Pham Viet Hoa
Advances in Remote Sensing (ARS) , 2016, DOI: 10.4236/ars.2016.54022
Abstract: Many researches have been performed comparing object-based classification (OBC) and pixel-based classification (PBC), particularly in classifying high-resolution satellite images. VNREDSat-1 is the first optical remote sensing satellite of Vietnam with resolution of 2.5 m (Panchromatic) and 10 m (Multispectral). The objective of this research is to compare two classification approaches using VNREDSat-1 image for mapping mangrove forest in Vien An Dong commune, Ngoc Hien district, Ca Mau province. ISODATA algorithm (in PBC method) and membership function classifier (in OBC method) were chosen to classify the same image. The results show that the overall accuracies of OBC and PBC are 73% and 62.16% respectively, and OBC solved the “salt and pepper” which is the main issue of PBC as well. Therefore, OBC is supposed to be the better approach to classify VNREDSat-1 for mapping mangrove forest in Ngoc Hien commune.
K-theory for the Leaf Space of Foliations Formed by the Generic K-orbits of a class of Solvable Real Lie Groups
Le Anh Vu,Duong Quang Hoa,Nguyen Anh Tuan
Mathematics , 2014,
Abstract: The paper is a continuation of the works [17] of Vu and Shum, [18] and [19] of Vu and Hoa. In [17], Vu and Shum classified all the MD5-algebras having commutative derived ideals. In [18], Vu and Hoa considered foliations formed by the maximal dimensional K-orbits (for short, MD5-foliations) of connected MD5-groups such that their Lie algebras have 4-dimensional commutative derived ideals and gave a topological classification of the considered foliations. In [19], Vu and Hoa characterized the Connes' C*-algebras of some MD5-foliations considered in \cite{VU-HO09} by the method of K-functors. In this paper, we study K-theory for the leaf space of all MD5-foliations which are classified in [18] and characterize the Connes' C*-algebras of them by the method of K-functors.
K-theory for the Leaf Spaces of the Orbit Foliations of the co-adjoint Action of some 5-dimensional Solvable Lie groups
Le Anh Vu,Nguyen Anh Tuan,Duong Quang Hoa
Mathematics , 2014,
Abstract: In this paper, combining Kirillov's method of orbits with Connes' method in Differential Geometry, we study the so-called MD(5,3C)-foliations, i.e. the orbit foliations of the co-adjoint action of MD(5,3C)-groups. First, we classify topologically MD(5,3C)-foliations based on the classification of all MD(5,3C)-algebras in [22] and the picture of co-adjoint orbits (K-orbits) of all MD(5,3C)-groups in [23]. Finally, we study K-theory for leaf space of MD(5,3C)-foliations and describe analytically or characterize Connes' C*-algebras of the considered foliations by KK-functors.
Influence of Chitosan Binder on the Adhesion of Silver Nanoparticles on Cotton Fabric and Evaluation of Antibacterial Activity  [PDF]
Nguyen Quoc Hien, Dang Van Phu, Nguyen Ngoc Duy, Le Anh Quoc, Nguyen T. Kim Lan, Hoang T. Dong Quy, Huynh T. Hong Van, Phan Ha Nu Diem, Tran Thai Hoa
Advances in Nanoparticles (ANP) , 2015, DOI: 10.4236/anp.2015.44011
Abstract: Colloidal silver nanoparticles (AgNPs) with particle size less than 10 nm and concentration of 2 mM/L (~200 mg/L) were synthesized by gamma Co-60 ray irradiation of Ag+/chitosan solutions with different chitosan concentration of 0.5%, 1% and 2% (w/v). Incorporation of AgNPs onto cotton fabric was carried out by padding method with 100% wet pick-up. The content of AgNPs deposited on cotton fabric and released from cotton fabric after repeated washing was determined by inductively couple plasma-atomic emission spectroscopy (ICP-AES). The results indicated that cotton/AgNPs fabric made from padding into AgNPs solution with 0.5% - 1% chitosan was the best one of AgNPs adhesion ability on cotton fabric. Results on antibacterial activity against S. aureus showed that cotton/AgNPs fabric with AgNPs content more than 100 mg/kg exhibited highly antibacterial activity (η > 98%). The mechanical property (tensile strength and elongation) of cotton/AgNPs fabrics was almost unchanged in comparison with untreated cotton fabric. Thus, the resultant cotton/AgNPs fabric with highly antibacterial activity can be potentially used as bed drapes and/or patient uniforms in hospitals, etc.
Influenza A H5N1 and HIV co-infection: case report
Annette Fox, Peter Horby, Nguyen Ha, Le Nguyen Hoa, Nguyen Lam, Cameron Simmons, Jeremy Farrar, Nguyen Van Kinh, Heiman Wertheim
BMC Infectious Diseases , 2010, DOI: 10.1186/1471-2334-10-167
Abstract: A 30-year-old male was admitted on day 4 of influenza-like-illness with tachycardia, tachypnea, hypoxemia and bilateral pulmonary infiltrates. Influenza A/H5N1 and HIV tests were positive and the patient was treated with Oseltamivir and broad-spectrum antibiotics. Initially his condition improved coinciding with virus clearance by day 6. He clinically deteriorated as of day 10 with fever recrudescence and increasing neutrophil counts and died on day 16. His admission CD4 count was 100/μl and decreased until virus was cleared. CD8 T cells shifted to a CD27+CD28- phenotype. Plasma chemokine and cytokine levels were similar to those found previously in fatal H5N1.The course of H5N1 infection was not notably different from other cases. Virus was cleared despite profound CD4 T cell depletion and aberrant CD8 T cell activation but this may have increased susceptibility to a fatal secondary infection.Influenza A/H5N1 infection is characterized by high viral loads, overproduction of pro-inflammatory cytokines and chemokines, direct lung tissue destruction, pulmonary oedema and extensive inflammatory infiltration [1-3]. The prevailing view is that alveolar damage is the primary pathology leading to acute respiratory distress, multiple organ dysfunction syndrome and death [3]. Likewise, 2009 H1N1 infection can cause acute respiratory distress syndrome and death in previously healthy young adults very similar to the clinical syndrome seen in H5N1 [4].It remains unclear whether lung pathology in severe influenza is a direct consequence of high viral loads and/or of ensuing inflammatory responses. The involvement of innate versus adaptive immunity in inflammation or controlling viremia is also poorly defined. Further understanding of the pathological processes is necessary to develop interventions that prevent severe lung disease. The occurrence of H5N1 infection in a patient with HIV infection offered a unique opportunity to study the pathological and immunological process when
Long-Term Impact of Community-Based Information, Education and Communication Activities on Food Hygiene and Food Safety Behaviors in Vietnam: A Longitudinal Study
Kumiko Takanashi, Dao To Quyen, Nguyen Thi Le Hoa, Nguyen Cong Khan, Junko Yasuoka, Masamine Jimba
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070654
Abstract: Background Ingestion of contaminated water or food is a major contributor to childhood diarrhea in developing countries. In Vietnam, the use of community-based information, education and communication (IEC) activities could be a sustainable strategy to improve food hygiene and food safety behaviors. This study thus examined the long-term impact of community-based IEC activities on food hygiene and food safety behaviors. Methods In this longitudinal study, we interviewed caregivers of children aged between six months and four years in suburban Hanoi. Baseline data were collected in January 2006 (n = 125). After conducting IEC interventions, we collected a 1st set of evaluation data in January 2007 (n = 132). To examine the long-term impact of the interventions, we then collected a 2nd set of evaluation data in January 2008 (n = 185). Changes in childhood diarrhea prevalence, IEC coverage, and food hygiene and food safety behaviors were assessed over a two-year period using bivariate and logistic regression analyses. Effective IEC channels were determined through multiple linear regression analysis. Results Childhood diarrhea was significantly reduced from 21.6% at baseline to 7.6% at the 1st post-intervention evaluation (P = 0.002), and to 5.9% at the 2nd evaluation. Among 17 food hygiene and food safety behaviors measured, a total of 11 behaviors were improved or maintained by the 2nd evaluation. Handwashing after toilet use was significantly improved at both evaluation points. Overall, 3 food safety behaviors and 7 food hygiene behaviors were found to have significantly improved at the 1st and at the 2nd evaluations, respectively. Flip chart communication administered by community groups was identified to be the most effective IEC channel for effecting behavior change (P = 0.018). Conclusions Flip chart communication administered by community groups is effective for improving multiple food hygiene and food safety behaviors in sustainable ways, and should be included in water and health promotion programs.
Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss
Truong Quang Dang Khoa,Le Minh Hoa,Nguyen Thanh Hai,Vo Van Toi
BioMedical Engineering OnLine , 2012, DOI: 10.1186/1475-925x-11-55
Abstract: Background This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. Methods In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. Results The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. Conclusions This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength.
Influenza Infection Rates, Measurement Errors and the Interpretation of Paired Serology
Simon Cauchemez ,Peter Horby,Annette Fox,Le Quynh Mai,Le Thi Thanh,Pham Quang Thai,Le Nguyen Minh Hoa,Nguyen Tran Hien,Neil M. Ferguson
PLOS Pathogens , 2012, DOI: 10.1371/journal.ppat.1003061
Abstract: Serological studies are the gold standard method to estimate influenza infection attack rates (ARs) in human populations. In a common protocol, blood samples are collected before and after the epidemic in a cohort of individuals; and a rise in haemagglutination-inhibition (HI) antibody titers during the epidemic is considered as a marker of infection. Because of inherent measurement errors, a 2-fold rise is usually considered as insufficient evidence for infection and seroconversion is therefore typically defined as a 4-fold rise or more. Here, we revisit this widely accepted 70-year old criterion. We develop a Markov chain Monte Carlo data augmentation model to quantify measurement errors and reconstruct the distribution of latent true serological status in a Vietnamese 3-year serological cohort, in which replicate measurements were available. We estimate that the 1-sided probability of a 2-fold error is 9.3% (95% Credible Interval, CI: 3.3%, 17.6%) when antibody titer is below 10 but is 20.2% (95% CI: 15.9%, 24.0%) otherwise. After correction for measurement errors, we find that the proportion of individuals with 2-fold rises in antibody titers was too large to be explained by measurement errors alone. Estimates of ARs vary greatly depending on whether those individuals are included in the definition of the infected population. A simulation study shows that our method is unbiased. The 4-fold rise case definition is relevant when aiming at a specific diagnostic for individual cases, but the justification is less obvious when the objective is to estimate ARs. In particular, it may lead to large underestimates of ARs. Determining which biological phenomenon contributes most to 2-fold rises in antibody titers is essential to assess bias with the traditional case definition and offer improved estimates of influenza ARs.
RESEARCH: Urbanization and Vulnerable Groups
Nguyen Minh-Hoa
Kasarinlan : Philippine Journal of Third World Studies , 2002,
Abstract: Social stratification or the widening of income gap between the rich and the poor becomes a serious predicament whenever Asian countries experience rapid urbanization and industrialization. The author explores the urbanization of Ho Chi Minh City (HCMC) and the vulnerable groups created by its processes, notably, a new urban poor sector comprised of spontaneous immigrant groups. Vulnerable groups, defined as "individuals or households who have unstable lives", account for the swelling urban population, high crime incidence and social unrest. A thorough study of these groups could positively transform government policies and the public mind-set toward them. Four conditions are described as vulnerability factors: 1) weak policies of the leading party and the government, 2)problems in the household, 3) risk and sudden changes, and 4) lack of social capital. To measure social poverty, the concep..s of vulnerability and vulnerable groups are introduced as a quid pro quo of the quantitative indicator poverty line (Pl). Urbanization, through the conversion of agricultural lands into industrial and commercial zones, alters the job structure of the rural sector. Rural farmers struggle to adjust to new social circumstances. Moreover, the poor are disenfranchised of their rights to affect the government's decision-making process. The phenomenon of "virtual urban planning" emerges, as huge urban projects remain unfulfilled because of social impediments.
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