Manh Nguyen - Academia.edu (original) (raw)
Papers by Manh Nguyen
ChemPhysChem, 2015
Density functional calculations are performed to study the energetic, structural, and electronic ... more Density functional calculations are performed to study the energetic, structural, and electronic properties of graphene and silicene functionalized with hydrogen. Our calculations predict that H atoms bind much more strongly to silicene than to graphene. The adsorbed H atoms tend to cooperatively stabilize each other leading to a two-dimensional nucleation and growth mechanism. The different structural and electronic modifications induced by H in fully functionalized graphene and silicene (known as graphane and silicane) are also explained. Finally, the electronic properties of defective graphane with multiple hydrogen vacancies are investigated. Engineering the vacancies in graphane offers a way to modify the electronic properties of this material.
ChemPhysChem, 2014
By using density functional theory calculations at the PBE+U level, we investigated the propertie... more By using density functional theory calculations at the PBE+U level, we investigated the properties of hematite (0001) surfaces decorated with adatoms/vacancies/substituents. For the most stable surface termination over a large range of oxygen chemical potentials (muO), the vacancy formation and adsorption energies were determined as a function of muO. Under oxygen-rich conditions, all defects are metastable with respect to the ideal surface. Under oxygen-poor conditions, O vacancies and Fe adatoms become stable. Under ambient conditions, all defects are metastable; in the bulk, O vacancies form more easily than Fe vacancies, whereas at the surface the opposite is true. All defects, that is, O and Fe vacancies, Fe and Al adatoms, and Al substituents, induce important modifications to the geometry of the surface in their vicinity. Dissociative adsorption of molecular oxygen is likely to be exothermic on surfaces with Fe/Al adatoms or O vacancies.
Solid State Communications, 2008
Saturated hydrocarbons, though relatively inert in nature, may become more reactive by functional... more Saturated hydrocarbons, though relatively inert in nature, may become more reactive by functionalization. Using first-principles computational methods, we perform a systematic search for functional groups to be attached to saturated hydrocarbons for high-capacity storage ...
Journal of the American Chemical Society, 2013
Chiral recognition as well as chirality transfer in supramolecular self-assembly and on-surface c... more Chiral recognition as well as chirality transfer in supramolecular self-assembly and on-surface coordination is studied for the enantiopure 6,13-dicyano[7]helicene building block. It is remarkable that, with this helical molecule, both H-bonded chains and metal-coordinated chains can be formed on the same substrate, thereby allowing for a direct comparison of the chain bonding motifs and their effects on the self-assembly in experiment and theory. Conformational flexure and both adsorbate/adsorbent and intermolecular interactions can be identified as factors influencing the chiral recognition at the binding site. The observed H-bonded chains are chiral, however, the overall appearance of Cu-coordinated chains is no longer chiral. The study was performed via scanning tunneling microscopy, X-ray-photoelectron spectroscopy and density functional theory calculations. We show a significant influence of the molecular flexibility and the type of bonding motif on the chirality transfer in the 1D self-assembly.
Journal of Chemical Theory and Computation, 2013
A novel method for including polarization effects within hybrid quantum mechanics/molecular mecha... more A novel method for including polarization effects within hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of adsorbate-metal systems is presented. The interactions between adsorbate (QM) and metallic substrate (MM) are described at the MM level of theory. Induction effects are additionally accounted for by applying the image charge formulation. The charge distribution induced within the metallic substrate is modeled by a set of Gaussian charges (image charges) centered at the metal atoms. The image charges and the electrostatic response of the QM potential are determined self-consistently by imposing the constant-potential condition within the metal. The implementation is embedded in a highly efficient Gaussian and plane wave framework and is naturally suited for periodic systems. Even though the electronic properties of the metallic substrate are not taken into account explicitly, the augmented QM/MM scheme can reproduce characteristic polarization effects of the adsorbate. The method is assessed through the investigation of structural and electronic properties of benzene, nitrobenzene, thymine, and guanine on Au(111). The study of small water clusters adsorbed on Pt(111) is also reported in order to demonstrate that the approach provides a sizable correction of the MM-based interactions between adsorbate and substrate. Large-scale molecular dynamics (MD) simulations of a water film in contact with a Pt(111) surface show that the method is suitable for simulations of liquid/metal interfaces at reduced computational cost.
Heart, 2013
Many patients delay or interrupt dual antiplatelet therapy (DAT) after drug-eluting stent (DES) i... more Many patients delay or interrupt dual antiplatelet therapy (DAT) after drug-eluting stent (DES) implantation, which increases the risk of stent thrombosis and death. To test the hypothesis that simple telephone contact made by nurses would improve adherence to and persistence of DAT. Randomised controlled trial. A total of 300 patients (mean±SD 64±10 years, 73% male) were recruited immediately after DES implantation performed between June 2009 and June 2010. The last patient recruited reached the 1-year follow-up time point in June 2011. Patients were randomised to one of two groups: intervention, with four telephone follow-ups, versus a control group. In the intervention group, phone calls were made within 7 days of the DES implantation and at 1, 6 and 9 months to support drug adherence. Control patients were followed as per usual clinical practice. Pharmacy data were collected to assess drug prescription filling and refill. Tertiary care university cardiovascular centre and community. The primary end point was the proportion of days covered with aspirin and clopidogrel over the year after discharge as assessed by pharmacy refill data. Secondary outcome measures included persistence of aspirin and clopidogrel treatment, defined as no gaps longer than 14 days during follow-up. Most patients (73%) underwent DES implantation in the context of an acute coronary syndrome. All patients had drug insurance cover, either from the public plan (59%) or through private plans (41%). Complete pharmacy follow-up data were available for 96% of the cohort. At 12 months, median scores (25th-75th centile) for adherence to aspirin and clopidogrel were 99.2% (97.5-100%) and 99.3% (97.5-100%), respectively, in the intervention group compared with 90.2% (84.2-95.4%) and 91.5% (85.1-96.0%), respectively, in the control group (p<0.0001 for aspirin and clopidogrel). Patients in the intervention group were significantly more persistent in the aspirin and clopidogrel treatment than those in the control group. For clopidogrel, 87.2% of patients in the intervention group were still persistent at 12 months compared with only 43.1% in the control group (p<0.0001). A simple approach of four telephone calls to patients after DES implantation significantly improved 1-year drug adherence to near-perfect scores. Persistence of DAT was also significantly improved by the intervention.
…, 2010
Hydrogen has long been considered as a carbon-dioxide-free energy carrier of the future. However,... more Hydrogen has long been considered as a carbon-dioxide-free energy carrier of the future. However, storing hydrogen effi-ciently and safely is still a major obstacle to the practical usage of hydrogen energy. Instead of traditional storing modes such as compressed gas, ...
Physical Review B, 2009
Using density functional theory electronic structure calculations, we investigate the calcium-hyd... more Using density functional theory electronic structure calculations, we investigate the calcium-hydroxyl group complex for potential applications to the hydrogen storage at near ambient temperature and pressure. The Ca atom is bound to the hydroxyl group with a binding energy ...
The aim of this study was to examine the effect of resolution from metabolic syndrome (MetS) betw... more The aim of this study was to examine the effect of resolution from metabolic syndrome (MetS) between youth and adulthood on carotid artery intima-media thickness (IMT) and type 2 diabetes mellitus (T2DM). Published findings demonstrate that youth with MetS are at increased risk of cardio-metabolic outcomes in adulthood. It is not known whether this risk is attenuated in those who resolve their MetS status. Participants (n = 1,757) from 2 prospective cohort studies were examined as youth (when 9 to 18 years of age) and re-examined 14 to 27 years later. The presence of any 3 components (low high-density lipoprotein cholesterol, high triglycerides, high glucose, high blood pressure, or high body mass index) previously shown to predict adult outcomes defined youth MetS; the harmonized MetS criteria defined adulthood MetS. Participants were classified according to their MetS status at baseline and follow-up and examined for risk of high IMT and T2DM. Those with MetS in youth and adulthood were at 3.4 times the risk (95% confidence interval: 2.4 to 4.9) of high IMT and 12.2 times the risk (95% confidence interval: 6.3 to 23.9) of T2DM in adulthood compared with those that did not have MetS at either time-point, whereas those that had resolved their youth MetS status by adulthood showed similar risk to those that did not have MetS at either time-point (p > 0.20 for all comparisons). Although youth with MetS are at increased risk of adult high IMT and T2DM, these data indicate that the resolution of youth MetS by adulthood can go some way to normalize this risk to levels seen in those who have never had MetS.
The American Journal of Cardiology, 2010
International Journal of Advanced Research in Artificial Intelligence, 2015
Trust is considered as the crucial factor for agents in decision making to choose the most trustw... more Trust is considered as the crucial factor for agents in decision making to choose the most trustworthy partner during their interaction in open distributed multiagent systems. Most current trust models are the combination of experience trust and reference trust, in which the reference trust is estimated from the judgements of agents in the community about a given partner. These models are based on the assumption that all agents are reliable when they share their judgements about a given partner to the others. However, these models are no more longer appropriate to applications of multiagent systems, where several concurrent agents may not be ready to share their private judgement about others or may share the wrong data by lying to their partners.
The 2011 International Conference on Advanced Technologies for Communications (ATC 2011), 2011
ABSTRACT We consider the problem of constructing public-key encryption schemes that are resilient... more ABSTRACT We consider the problem of constructing public-key encryption schemes that are resilient to chosen-ciphertext and key-leakage attach. In this paper, we present a generic construction of public-key encryption that is resilient to this attack from any 1-universal hash proof system and any 4-wise independent hash function. As shown in the paper [6] they can be instantiated with efficient schemes based on standard intractability assumptions such as Decisional Diffie-Hellman, Quadratic Residuosity, and Pailliers Decisional Composite Residuosity.
In this paper we first give an elementary proof of existence of equilibrium with dividends in an ... more In this paper we first give an elementary proof of existence of equilibrium with dividends in an economy with possibly satiated consumers. We then introduce a no-arbitrage condition and show that it is equivalent to the existence of equilibrium with dividends.
IEEE International Conference on Research, Innovation and Vision for the Future, 2012
Evaluation and early warning for Tsunami disasters in coastal areas and islands need to research ... more Evaluation and early warning for Tsunami disasters in coastal areas and islands need to research to save people and mitigate damages. This paper addresses the simulation of pedestrians evacuating along the road network in city. In a developing country, the coastal city often has a complicated roads network and the devices to support an evacuation are simple and shortage so the alert signs are the good devices. We assume that there is a given alert signs system in the city, pedestrians facing a Tsunami have difference behaviors with the signs. The simulations's result help us to estimate the number of survivors and the global amount of rescue time. Agent based model is used to build the evacuation of pedestrians with details behaviors of them. The simulation of pedestrians evacuation in this article using the heterogeneous environment Geographic Information Systems(GIS) supporting realistic simulations. In addition, the simulation is applied for road networks in Nhatrang city.
Revue économique, 1998
[eng] Pollution control and international trade in a monopolistic competition framework. . We est... more [eng] Pollution control and international trade in a monopolistic competition framework. . We establish in a model of monopolistic competition that the effects of a pollution abatement effort on the equilibrium value of strategic variables depend on how this effort would modify the degree of economies of scale. The effects of market size, on the other hand, depend entirely on
Open Access Journal of Sports Medicine, 2012
Objective: Evaluating the effects of Tai Chi exercise on physical fitness, blood pressure, and pe... more Objective: Evaluating the effects of Tai Chi exercise on physical fitness, blood pressure, and perceived health in community-dwelling elderly. Design: A randomized controlled trial. Setting: Community-dwelling elderly in Vinh city, Vietnam. Participants: Ninety-six community-dwelling participants aged 60 to 79 years (68.9 ± 5.1 years) were recruited. Intervention: Subjects were divided randomly into two groups: Tai Chi and Control groups. Participants in the Tai Chi group (aged 69.02 ± 5.16 years) attended a 60-minute Tai Chi practice session twice a week for 6 months. The session consisted of a 15-minute warm-up and a 15-minute cool-down period. The Control group (aged 68.72 ± 4.94 years) maintained routine daily activities. Outcome measures: The Senior Fitness Test and Short-Form 36 ® (SF-36 ® ) are primary outcome measures. Results: After 24 weeks of the Tai Chi training program, the intervention group showed significant decrease in systole of 12 mmHg and heart rate 6.46 bpm. Body mass index and waist-hip ratio were also reduced by 1.23 and 0.04, respectively. The Senior Fitness Test and SF-36 showed significant improvement. Conclusion: In this randomized controlled trial study, Tai Chi is beneficial to improve systole blood pressure, heart rate, body mass index, waist-hip ratio, perceived health, and physical fitness. Assessment of the effects of Tai Chi may be focused more on chronic disease with a long-term training program in the future.
A linear diffraction radiation hydrodynamic solver for flows around ship was extended to take int... more A linear diffraction radiation hydrodynamic solver for flows around ship was extended to take into account for the lifting effects on fins, rudders or stabilizers (code Poseidon: panel method in the frequency domain using the diffractionradiation Green function). This modelisation is based on a doublet distribution set on the symmetry plane of the body, and on semi infinite strips extending from the trailing edge, simulating the wake assumed to be plane. A linearized unsteady Kutta-Joukowsky condition enforcing the continuity of the unsteady pressure at the trailing edge is satisfied. The distribution law for the doublet intensity on the body symmetry-plan was selected in order to improve the resulting matrix conditioning. Validation was obtained through comparisons of our results with those available for the cases of a deeply submerged body and weakly submerged and surface piercing 2D and 3D bodies. Application to flows with lifting effects is presented.
Working Papers, 2008
This paper studies an optimal endogenous growth model using physical capital, labor and two kinds... more This paper studies an optimal endogenous growth model using physical capital, labor and two kinds of natural resources in the final goods sector and employing labor to accumulate knowledge. Based on results in calculus of variations, a direct proof of existence of optimal solution is provided. Analytical solutions for the planner case and the balanced growth paths are found for a specific CRRA utility and Cobb-Douglas production function. Transitional dynamics to the steady state from the theoretical model are used to derive three convergence equations of output intensity growth rate, exhaustible resource growth rate and renewable growth rate, which are tested based on data on production and energy consumption in 27 OECD countries.
Working Papers, 2008
In this paper we first give an elementary proof of existence of equilibrium with dividends in an ... more In this paper we first give an elementary proof of existence of equilibrium with dividends in an economy with possibly satiated consumers. We then introduce a no-arbitrage condition and show that it is equivalent to the existence of equilibrium with dividends.
ChemPhysChem, 2015
Density functional calculations are performed to study the energetic, structural, and electronic ... more Density functional calculations are performed to study the energetic, structural, and electronic properties of graphene and silicene functionalized with hydrogen. Our calculations predict that H atoms bind much more strongly to silicene than to graphene. The adsorbed H atoms tend to cooperatively stabilize each other leading to a two-dimensional nucleation and growth mechanism. The different structural and electronic modifications induced by H in fully functionalized graphene and silicene (known as graphane and silicane) are also explained. Finally, the electronic properties of defective graphane with multiple hydrogen vacancies are investigated. Engineering the vacancies in graphane offers a way to modify the electronic properties of this material.
ChemPhysChem, 2014
By using density functional theory calculations at the PBE+U level, we investigated the propertie... more By using density functional theory calculations at the PBE+U level, we investigated the properties of hematite (0001) surfaces decorated with adatoms/vacancies/substituents. For the most stable surface termination over a large range of oxygen chemical potentials (muO), the vacancy formation and adsorption energies were determined as a function of muO. Under oxygen-rich conditions, all defects are metastable with respect to the ideal surface. Under oxygen-poor conditions, O vacancies and Fe adatoms become stable. Under ambient conditions, all defects are metastable; in the bulk, O vacancies form more easily than Fe vacancies, whereas at the surface the opposite is true. All defects, that is, O and Fe vacancies, Fe and Al adatoms, and Al substituents, induce important modifications to the geometry of the surface in their vicinity. Dissociative adsorption of molecular oxygen is likely to be exothermic on surfaces with Fe/Al adatoms or O vacancies.
Solid State Communications, 2008
Saturated hydrocarbons, though relatively inert in nature, may become more reactive by functional... more Saturated hydrocarbons, though relatively inert in nature, may become more reactive by functionalization. Using first-principles computational methods, we perform a systematic search for functional groups to be attached to saturated hydrocarbons for high-capacity storage ...
Journal of the American Chemical Society, 2013
Chiral recognition as well as chirality transfer in supramolecular self-assembly and on-surface c... more Chiral recognition as well as chirality transfer in supramolecular self-assembly and on-surface coordination is studied for the enantiopure 6,13-dicyano[7]helicene building block. It is remarkable that, with this helical molecule, both H-bonded chains and metal-coordinated chains can be formed on the same substrate, thereby allowing for a direct comparison of the chain bonding motifs and their effects on the self-assembly in experiment and theory. Conformational flexure and both adsorbate/adsorbent and intermolecular interactions can be identified as factors influencing the chiral recognition at the binding site. The observed H-bonded chains are chiral, however, the overall appearance of Cu-coordinated chains is no longer chiral. The study was performed via scanning tunneling microscopy, X-ray-photoelectron spectroscopy and density functional theory calculations. We show a significant influence of the molecular flexibility and the type of bonding motif on the chirality transfer in the 1D self-assembly.
Journal of Chemical Theory and Computation, 2013
A novel method for including polarization effects within hybrid quantum mechanics/molecular mecha... more A novel method for including polarization effects within hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of adsorbate-metal systems is presented. The interactions between adsorbate (QM) and metallic substrate (MM) are described at the MM level of theory. Induction effects are additionally accounted for by applying the image charge formulation. The charge distribution induced within the metallic substrate is modeled by a set of Gaussian charges (image charges) centered at the metal atoms. The image charges and the electrostatic response of the QM potential are determined self-consistently by imposing the constant-potential condition within the metal. The implementation is embedded in a highly efficient Gaussian and plane wave framework and is naturally suited for periodic systems. Even though the electronic properties of the metallic substrate are not taken into account explicitly, the augmented QM/MM scheme can reproduce characteristic polarization effects of the adsorbate. The method is assessed through the investigation of structural and electronic properties of benzene, nitrobenzene, thymine, and guanine on Au(111). The study of small water clusters adsorbed on Pt(111) is also reported in order to demonstrate that the approach provides a sizable correction of the MM-based interactions between adsorbate and substrate. Large-scale molecular dynamics (MD) simulations of a water film in contact with a Pt(111) surface show that the method is suitable for simulations of liquid/metal interfaces at reduced computational cost.
Heart, 2013
Many patients delay or interrupt dual antiplatelet therapy (DAT) after drug-eluting stent (DES) i... more Many patients delay or interrupt dual antiplatelet therapy (DAT) after drug-eluting stent (DES) implantation, which increases the risk of stent thrombosis and death. To test the hypothesis that simple telephone contact made by nurses would improve adherence to and persistence of DAT. Randomised controlled trial. A total of 300 patients (mean±SD 64±10 years, 73% male) were recruited immediately after DES implantation performed between June 2009 and June 2010. The last patient recruited reached the 1-year follow-up time point in June 2011. Patients were randomised to one of two groups: intervention, with four telephone follow-ups, versus a control group. In the intervention group, phone calls were made within 7 days of the DES implantation and at 1, 6 and 9 months to support drug adherence. Control patients were followed as per usual clinical practice. Pharmacy data were collected to assess drug prescription filling and refill. Tertiary care university cardiovascular centre and community. The primary end point was the proportion of days covered with aspirin and clopidogrel over the year after discharge as assessed by pharmacy refill data. Secondary outcome measures included persistence of aspirin and clopidogrel treatment, defined as no gaps longer than 14 days during follow-up. Most patients (73%) underwent DES implantation in the context of an acute coronary syndrome. All patients had drug insurance cover, either from the public plan (59%) or through private plans (41%). Complete pharmacy follow-up data were available for 96% of the cohort. At 12 months, median scores (25th-75th centile) for adherence to aspirin and clopidogrel were 99.2% (97.5-100%) and 99.3% (97.5-100%), respectively, in the intervention group compared with 90.2% (84.2-95.4%) and 91.5% (85.1-96.0%), respectively, in the control group (p<0.0001 for aspirin and clopidogrel). Patients in the intervention group were significantly more persistent in the aspirin and clopidogrel treatment than those in the control group. For clopidogrel, 87.2% of patients in the intervention group were still persistent at 12 months compared with only 43.1% in the control group (p<0.0001). A simple approach of four telephone calls to patients after DES implantation significantly improved 1-year drug adherence to near-perfect scores. Persistence of DAT was also significantly improved by the intervention.
…, 2010
Hydrogen has long been considered as a carbon-dioxide-free energy carrier of the future. However,... more Hydrogen has long been considered as a carbon-dioxide-free energy carrier of the future. However, storing hydrogen effi-ciently and safely is still a major obstacle to the practical usage of hydrogen energy. Instead of traditional storing modes such as compressed gas, ...
Physical Review B, 2009
Using density functional theory electronic structure calculations, we investigate the calcium-hyd... more Using density functional theory electronic structure calculations, we investigate the calcium-hydroxyl group complex for potential applications to the hydrogen storage at near ambient temperature and pressure. The Ca atom is bound to the hydroxyl group with a binding energy ...
The aim of this study was to examine the effect of resolution from metabolic syndrome (MetS) betw... more The aim of this study was to examine the effect of resolution from metabolic syndrome (MetS) between youth and adulthood on carotid artery intima-media thickness (IMT) and type 2 diabetes mellitus (T2DM). Published findings demonstrate that youth with MetS are at increased risk of cardio-metabolic outcomes in adulthood. It is not known whether this risk is attenuated in those who resolve their MetS status. Participants (n = 1,757) from 2 prospective cohort studies were examined as youth (when 9 to 18 years of age) and re-examined 14 to 27 years later. The presence of any 3 components (low high-density lipoprotein cholesterol, high triglycerides, high glucose, high blood pressure, or high body mass index) previously shown to predict adult outcomes defined youth MetS; the harmonized MetS criteria defined adulthood MetS. Participants were classified according to their MetS status at baseline and follow-up and examined for risk of high IMT and T2DM. Those with MetS in youth and adulthood were at 3.4 times the risk (95% confidence interval: 2.4 to 4.9) of high IMT and 12.2 times the risk (95% confidence interval: 6.3 to 23.9) of T2DM in adulthood compared with those that did not have MetS at either time-point, whereas those that had resolved their youth MetS status by adulthood showed similar risk to those that did not have MetS at either time-point (p > 0.20 for all comparisons). Although youth with MetS are at increased risk of adult high IMT and T2DM, these data indicate that the resolution of youth MetS by adulthood can go some way to normalize this risk to levels seen in those who have never had MetS.
The American Journal of Cardiology, 2010
International Journal of Advanced Research in Artificial Intelligence, 2015
Trust is considered as the crucial factor for agents in decision making to choose the most trustw... more Trust is considered as the crucial factor for agents in decision making to choose the most trustworthy partner during their interaction in open distributed multiagent systems. Most current trust models are the combination of experience trust and reference trust, in which the reference trust is estimated from the judgements of agents in the community about a given partner. These models are based on the assumption that all agents are reliable when they share their judgements about a given partner to the others. However, these models are no more longer appropriate to applications of multiagent systems, where several concurrent agents may not be ready to share their private judgement about others or may share the wrong data by lying to their partners.
The 2011 International Conference on Advanced Technologies for Communications (ATC 2011), 2011
ABSTRACT We consider the problem of constructing public-key encryption schemes that are resilient... more ABSTRACT We consider the problem of constructing public-key encryption schemes that are resilient to chosen-ciphertext and key-leakage attach. In this paper, we present a generic construction of public-key encryption that is resilient to this attack from any 1-universal hash proof system and any 4-wise independent hash function. As shown in the paper [6] they can be instantiated with efficient schemes based on standard intractability assumptions such as Decisional Diffie-Hellman, Quadratic Residuosity, and Pailliers Decisional Composite Residuosity.
In this paper we first give an elementary proof of existence of equilibrium with dividends in an ... more In this paper we first give an elementary proof of existence of equilibrium with dividends in an economy with possibly satiated consumers. We then introduce a no-arbitrage condition and show that it is equivalent to the existence of equilibrium with dividends.
IEEE International Conference on Research, Innovation and Vision for the Future, 2012
Evaluation and early warning for Tsunami disasters in coastal areas and islands need to research ... more Evaluation and early warning for Tsunami disasters in coastal areas and islands need to research to save people and mitigate damages. This paper addresses the simulation of pedestrians evacuating along the road network in city. In a developing country, the coastal city often has a complicated roads network and the devices to support an evacuation are simple and shortage so the alert signs are the good devices. We assume that there is a given alert signs system in the city, pedestrians facing a Tsunami have difference behaviors with the signs. The simulations's result help us to estimate the number of survivors and the global amount of rescue time. Agent based model is used to build the evacuation of pedestrians with details behaviors of them. The simulation of pedestrians evacuation in this article using the heterogeneous environment Geographic Information Systems(GIS) supporting realistic simulations. In addition, the simulation is applied for road networks in Nhatrang city.
Revue économique, 1998
[eng] Pollution control and international trade in a monopolistic competition framework. . We est... more [eng] Pollution control and international trade in a monopolistic competition framework. . We establish in a model of monopolistic competition that the effects of a pollution abatement effort on the equilibrium value of strategic variables depend on how this effort would modify the degree of economies of scale. The effects of market size, on the other hand, depend entirely on
Open Access Journal of Sports Medicine, 2012
Objective: Evaluating the effects of Tai Chi exercise on physical fitness, blood pressure, and pe... more Objective: Evaluating the effects of Tai Chi exercise on physical fitness, blood pressure, and perceived health in community-dwelling elderly. Design: A randomized controlled trial. Setting: Community-dwelling elderly in Vinh city, Vietnam. Participants: Ninety-six community-dwelling participants aged 60 to 79 years (68.9 ± 5.1 years) were recruited. Intervention: Subjects were divided randomly into two groups: Tai Chi and Control groups. Participants in the Tai Chi group (aged 69.02 ± 5.16 years) attended a 60-minute Tai Chi practice session twice a week for 6 months. The session consisted of a 15-minute warm-up and a 15-minute cool-down period. The Control group (aged 68.72 ± 4.94 years) maintained routine daily activities. Outcome measures: The Senior Fitness Test and Short-Form 36 ® (SF-36 ® ) are primary outcome measures. Results: After 24 weeks of the Tai Chi training program, the intervention group showed significant decrease in systole of 12 mmHg and heart rate 6.46 bpm. Body mass index and waist-hip ratio were also reduced by 1.23 and 0.04, respectively. The Senior Fitness Test and SF-36 showed significant improvement. Conclusion: In this randomized controlled trial study, Tai Chi is beneficial to improve systole blood pressure, heart rate, body mass index, waist-hip ratio, perceived health, and physical fitness. Assessment of the effects of Tai Chi may be focused more on chronic disease with a long-term training program in the future.
A linear diffraction radiation hydrodynamic solver for flows around ship was extended to take int... more A linear diffraction radiation hydrodynamic solver for flows around ship was extended to take into account for the lifting effects on fins, rudders or stabilizers (code Poseidon: panel method in the frequency domain using the diffractionradiation Green function). This modelisation is based on a doublet distribution set on the symmetry plane of the body, and on semi infinite strips extending from the trailing edge, simulating the wake assumed to be plane. A linearized unsteady Kutta-Joukowsky condition enforcing the continuity of the unsteady pressure at the trailing edge is satisfied. The distribution law for the doublet intensity on the body symmetry-plan was selected in order to improve the resulting matrix conditioning. Validation was obtained through comparisons of our results with those available for the cases of a deeply submerged body and weakly submerged and surface piercing 2D and 3D bodies. Application to flows with lifting effects is presented.
Working Papers, 2008
This paper studies an optimal endogenous growth model using physical capital, labor and two kinds... more This paper studies an optimal endogenous growth model using physical capital, labor and two kinds of natural resources in the final goods sector and employing labor to accumulate knowledge. Based on results in calculus of variations, a direct proof of existence of optimal solution is provided. Analytical solutions for the planner case and the balanced growth paths are found for a specific CRRA utility and Cobb-Douglas production function. Transitional dynamics to the steady state from the theoretical model are used to derive three convergence equations of output intensity growth rate, exhaustible resource growth rate and renewable growth rate, which are tested based on data on production and energy consumption in 27 OECD countries.
Working Papers, 2008
In this paper we first give an elementary proof of existence of equilibrium with dividends in an ... more In this paper we first give an elementary proof of existence of equilibrium with dividends in an economy with possibly satiated consumers. We then introduce a no-arbitrage condition and show that it is equivalent to the existence of equilibrium with dividends.