Tran Huynh Ngoc - Academia.edu (original) (raw)
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Papers by Tran Huynh Ngoc
2019 IEEE Vehicle Power and Propulsion Conference (VPPC), 2019
This paper presents the average consensus of a Multi Agent Systems (MAS) with non-uniform, asymme... more This paper presents the average consensus of a Multi Agent Systems (MAS) with non-uniform, asymmetric and time-varying delays in discrete integral systems. The MAS can be multi-electric vehicle system, multi-drone, multi-robot formations or an energy system. As an essential requirement of consensus control in MAS, there is the simultaneities of state quantities shared among agents. However, while the sharing of these state variables is performed via a communication network, there is the communication delay which is non-uniform and time-varying, so that the simultaneity between agents is lost and it becomes impossible to conserve the state variables of the whole system. In this paper, we firstly build a simulation model of the communication delay of an actual energy monitoring system. Next, we analyze the influence of communication delay on the average consensus by this model. From these results, we propose a restricted transmission and synchronization algorithm that can perform a good average consensus even in the presence of asymmetric, non-uniform, and time-varying delays. The proposed method adopts a communication protocol which can measure communication delay by sharing data sets of state variables and their sampling times among agents.
This paper presents a preliminary assessment of ALOS/PALSAR data from the Kyoto and Carbon Initia... more This paper presents a preliminary assessment of ALOS/PALSAR data from the Kyoto and Carbon Initiative program for monitoring of forest status and mapping of biomass in Vietnam. The changes in forest status (deforestation, reforestation, growth) occurred during three years (2007-20082009) were detected in a region of intensive rubber plantation program. Biomass estimation has been estimated in a province of active tree planting. Optical data (SPOT 5) have been used for mapping of forest types and in-situ biomass measurements have been used to analyse PALSAR data. The resulting biomass map of the Hoa Binh province has been validated using forest inventory data. The results obtained indicate that the forest biomass is relatively low (average values less than 40 ton/ha). This is due to the shortened exploitation cycle of the forest plantation (harvest of acacia mangium species after 4-5 years instead of 6-8 years). This change in the forest exploitation practices effects the carbon stoc...
How to practically maintain the frequency stability of large-scale power systems by a decentraliz... more How to practically maintain the frequency stability of large-scale power systems by a decentralized way is a simple but non-trivial question. In other words, is it possible to design any local controller without understanding the other controlled areas and with less understanding of network structure? With respect to the special properties of physical interaction between the local areas, this paper suggests two existing theories for tackling this issue. Firstly, passivity theory is shown to be a candidate for frequency control problem using swing equation. Based on the passivity of swing dynamics, it is possible to guarantee the system stability by designing for each local area a passive controller. We further extend the passivity approach to the hierarchically decentralized control system with unknown communication delay. Secondly, we discuss the application of generalized frequency variable (GFV) to the frequency control problem using area-control-error. Each local controller is d...
ISA Transactions, 2021
A stabilization approach for the average consensus of homogeneous multi-agent systems (MASs) enta... more A stabilization approach for the average consensus of homogeneous multi-agent systems (MASs) entailing non-uniform, asymmetric, and time-varying delays in communication networks is proposed. Agents are modeled using a continuous-time linear dynamical system with a local discrete-time controller. To address communication delays, we propose two logic functions, namely, a packet selection algorithm that constantly selects and updates the latest received control signal packets and a synchronization algorithm that asymmetrically synchronizes these packets to preserve the average value of state variables. Based on the Lyapunov theory, we establish a linear matrix inequality (LMI) condition that sufficiently guarantees the stability and consensus of the overall system. To establish this condition, only the time delay upper bound is required, without any special assumptions on the delay pattern. We thoroughly discuss the proposed algorithm and evaluate its effectiveness via numerical simulations.
Natural Product Communications, 2014
A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde... more A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde (3), 2-methoxycinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), coniferaldehyde (6), cinnamic acid (7), 2-hydroxycinnamic acid (8), and cinnamic alcohol (9), were isolated from the methanol extract of Cinnamomum cassia. Their structures were elucidated by spectral data and by comparison with the reported literature. The cytotoxic activities of compounds 1-9 were evaluated with two human cancer cell lines, HL-60 and A-549. Compound 1 showed growth inhibitory effects in the HL-60 and A-549 cell lines with IC50 values of 8.2 ± 0.5 and 11.3 ±1.1 μM, respectively. Compounds 3-6, and 8 exhibited moderate cytotoxicity with IC50 values ranging from 20.5 to 65.6 μM.
Ultrasonics, 1983
Abstract The acoustic field of a bounded finite-amplitude beam is governed by competing mechanism... more Abstract The acoustic field of a bounded finite-amplitude beam is governed by competing mechanisms such as medium non-linearity, interference, and attenuation. An analytic determination of the distribution of sonic energy in the individual harmonic components is often not reliable; consequently an experimental mapping of those harmonic components may be more appropriate. An experimental method is presented here which involves a miniature hydrophone probe which has been frequency calibrated for each harmonic component using a light diffraction technique. Measurements (made across the sound field) of the acoustic amplitude of the first three harmonic components are presented.
Vietnam Social Sciences, 2003
Abstract : A numerical integration method is developed for calculating the changes in beam profil... more Abstract : A numerical integration method is developed for calculating the changes in beam profile and amplitude upon reflection of a bounded ultrasonic beam incident on a liquid-solid flat interface at the longitudinal wave critical angle and the Rayleigh angle. No approximations, valid only at the Rayleigh angle, are used, and the method is applicable to all angles of incidence. (Author)
제6회 오송국제바이오심포지엄 제2회 한국식물과학협의회 공동국제심포지엄, Nov 1, 2007
Journal of Vacuum Science and Technology, 1972
Averaged Low-Energy Electron Diffraction Intensities from N¡(111)* Max G. Legally, Tran С. Ngoc, ... more Averaged Low-Energy Electron Diffraction Intensities from N¡(111)* Max G. Legally, Tran С. Ngoc, and Maurice B. Webb Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (Received 3 August 1971) Conventionally, crystal structures are determined by ...
The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D... more The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D radial numerical simulations with TOUGH2/ECO2N. To optimize the CO2 injec¬tion rate and the duration of injection, we carried out sensitivity analyses considering different values of completion interval for the single injection well, rock compressibility, and the ratio of vertical and horizontal permeabilities. Simulations took into account Bécancour reser¬voir conditions, in which injection pressure was limited below the fracturing threshold, and sensitivity analyses provided indications of potential injection scenarios. To remain below fracturing pressure, we propose intermittent 5-year injection periods, with a mass injection rate up to 20 kg/s, alter¬nating with half-year periods without injection. This scenario may provide maximum CO2 storage in the aquifer. We also calculated CO2 storage capacities in different phases versus time. The effective apparent capacity and injec¬tion cap...
1. Copy all information into one data sheet 2. Save as the version 2 3. Remember to "undo&qu... more 1. Copy all information into one data sheet 2. Save as the version 2 3. Remember to "undo" if you make a mistake 4. Assign ID number for each row (from 1 to final), which is useful to for you to identify when you make a mistake 5. Remove duplicate rows: Select column of name (then address, birthday, similar information); only select the data row (not title row); click "remove duplicates" button; select "continue with the current selection". If there is duplicated data, undo and find out and check the duplicated data. 6. Delete unnecessary columns (such as noted information) 7. Correct some strange characters using FIND/REPLACE 8. Find out missing data by counting cells (using formular: =COUNT(B3:B119)); missing data should be coded as blanked in excel. 9. Use the COUNTA function to count cells that contain values input (=COUNTA(B3:B119)) 10. Find out outlier mistakes by sorting each column; check Max and Min of data 11. Coding information for SPSS: make...
Physical Review Letters, 1971
That this twosided excitation merely enhanced sensitivity rvithout distorting the spectra via tra... more That this twosided excitation merely enhanced sensitivity rvithout distorting the spectra via transmission effects was checked by making a cavity in which a thicker potassium plate formed a conventional end wall.
2019 IEEE Vehicle Power and Propulsion Conference (VPPC), 2019
This paper presents the average consensus of a Multi Agent Systems (MAS) with non-uniform, asymme... more This paper presents the average consensus of a Multi Agent Systems (MAS) with non-uniform, asymmetric and time-varying delays in discrete integral systems. The MAS can be multi-electric vehicle system, multi-drone, multi-robot formations or an energy system. As an essential requirement of consensus control in MAS, there is the simultaneities of state quantities shared among agents. However, while the sharing of these state variables is performed via a communication network, there is the communication delay which is non-uniform and time-varying, so that the simultaneity between agents is lost and it becomes impossible to conserve the state variables of the whole system. In this paper, we firstly build a simulation model of the communication delay of an actual energy monitoring system. Next, we analyze the influence of communication delay on the average consensus by this model. From these results, we propose a restricted transmission and synchronization algorithm that can perform a good average consensus even in the presence of asymmetric, non-uniform, and time-varying delays. The proposed method adopts a communication protocol which can measure communication delay by sharing data sets of state variables and their sampling times among agents.
This paper presents a preliminary assessment of ALOS/PALSAR data from the Kyoto and Carbon Initia... more This paper presents a preliminary assessment of ALOS/PALSAR data from the Kyoto and Carbon Initiative program for monitoring of forest status and mapping of biomass in Vietnam. The changes in forest status (deforestation, reforestation, growth) occurred during three years (2007-20082009) were detected in a region of intensive rubber plantation program. Biomass estimation has been estimated in a province of active tree planting. Optical data (SPOT 5) have been used for mapping of forest types and in-situ biomass measurements have been used to analyse PALSAR data. The resulting biomass map of the Hoa Binh province has been validated using forest inventory data. The results obtained indicate that the forest biomass is relatively low (average values less than 40 ton/ha). This is due to the shortened exploitation cycle of the forest plantation (harvest of acacia mangium species after 4-5 years instead of 6-8 years). This change in the forest exploitation practices effects the carbon stoc...
How to practically maintain the frequency stability of large-scale power systems by a decentraliz... more How to practically maintain the frequency stability of large-scale power systems by a decentralized way is a simple but non-trivial question. In other words, is it possible to design any local controller without understanding the other controlled areas and with less understanding of network structure? With respect to the special properties of physical interaction between the local areas, this paper suggests two existing theories for tackling this issue. Firstly, passivity theory is shown to be a candidate for frequency control problem using swing equation. Based on the passivity of swing dynamics, it is possible to guarantee the system stability by designing for each local area a passive controller. We further extend the passivity approach to the hierarchically decentralized control system with unknown communication delay. Secondly, we discuss the application of generalized frequency variable (GFV) to the frequency control problem using area-control-error. Each local controller is d...
ISA Transactions, 2021
A stabilization approach for the average consensus of homogeneous multi-agent systems (MASs) enta... more A stabilization approach for the average consensus of homogeneous multi-agent systems (MASs) entailing non-uniform, asymmetric, and time-varying delays in communication networks is proposed. Agents are modeled using a continuous-time linear dynamical system with a local discrete-time controller. To address communication delays, we propose two logic functions, namely, a packet selection algorithm that constantly selects and updates the latest received control signal packets and a synchronization algorithm that asymmetrically synchronizes these packets to preserve the average value of state variables. Based on the Lyapunov theory, we establish a linear matrix inequality (LMI) condition that sufficiently guarantees the stability and consensus of the overall system. To establish this condition, only the time delay upper bound is required, without any special assumptions on the delay pattern. We thoroughly discuss the proposed algorithm and evaluate its effectiveness via numerical simulations.
Natural Product Communications, 2014
A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde... more A new coumarin derivative, coumacasia (1) and eight known compounds, coumarin (2), cinnamaldehyde (3), 2-methoxycinnamaldehyde (4), 2-hydroxycinnamaldehyde (5), coniferaldehyde (6), cinnamic acid (7), 2-hydroxycinnamic acid (8), and cinnamic alcohol (9), were isolated from the methanol extract of Cinnamomum cassia. Their structures were elucidated by spectral data and by comparison with the reported literature. The cytotoxic activities of compounds 1-9 were evaluated with two human cancer cell lines, HL-60 and A-549. Compound 1 showed growth inhibitory effects in the HL-60 and A-549 cell lines with IC50 values of 8.2 ± 0.5 and 11.3 ±1.1 μM, respectively. Compounds 3-6, and 8 exhibited moderate cytotoxicity with IC50 values ranging from 20.5 to 65.6 μM.
Ultrasonics, 1983
Abstract The acoustic field of a bounded finite-amplitude beam is governed by competing mechanism... more Abstract The acoustic field of a bounded finite-amplitude beam is governed by competing mechanisms such as medium non-linearity, interference, and attenuation. An analytic determination of the distribution of sonic energy in the individual harmonic components is often not reliable; consequently an experimental mapping of those harmonic components may be more appropriate. An experimental method is presented here which involves a miniature hydrophone probe which has been frequency calibrated for each harmonic component using a light diffraction technique. Measurements (made across the sound field) of the acoustic amplitude of the first three harmonic components are presented.
Vietnam Social Sciences, 2003
Abstract : A numerical integration method is developed for calculating the changes in beam profil... more Abstract : A numerical integration method is developed for calculating the changes in beam profile and amplitude upon reflection of a bounded ultrasonic beam incident on a liquid-solid flat interface at the longitudinal wave critical angle and the Rayleigh angle. No approximations, valid only at the Rayleigh angle, are used, and the method is applicable to all angles of incidence. (Author)
제6회 오송국제바이오심포지엄 제2회 한국식물과학협의회 공동국제심포지엄, Nov 1, 2007
Journal of Vacuum Science and Technology, 1972
Averaged Low-Energy Electron Diffraction Intensities from N¡(111)* Max G. Legally, Tran С. Ngoc, ... more Averaged Low-Energy Electron Diffraction Intensities from N¡(111)* Max G. Legally, Tran С. Ngoc, and Maurice B. Webb Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (Received 3 August 1971) Conventionally, crystal structures are determined by ...
The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D... more The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D radial numerical simulations with TOUGH2/ECO2N. To optimize the CO2 injec¬tion rate and the duration of injection, we carried out sensitivity analyses considering different values of completion interval for the single injection well, rock compressibility, and the ratio of vertical and horizontal permeabilities. Simulations took into account Bécancour reser¬voir conditions, in which injection pressure was limited below the fracturing threshold, and sensitivity analyses provided indications of potential injection scenarios. To remain below fracturing pressure, we propose intermittent 5-year injection periods, with a mass injection rate up to 20 kg/s, alter¬nating with half-year periods without injection. This scenario may provide maximum CO2 storage in the aquifer. We also calculated CO2 storage capacities in different phases versus time. The effective apparent capacity and injec¬tion cap...
1. Copy all information into one data sheet 2. Save as the version 2 3. Remember to "undo&qu... more 1. Copy all information into one data sheet 2. Save as the version 2 3. Remember to "undo" if you make a mistake 4. Assign ID number for each row (from 1 to final), which is useful to for you to identify when you make a mistake 5. Remove duplicate rows: Select column of name (then address, birthday, similar information); only select the data row (not title row); click "remove duplicates" button; select "continue with the current selection". If there is duplicated data, undo and find out and check the duplicated data. 6. Delete unnecessary columns (such as noted information) 7. Correct some strange characters using FIND/REPLACE 8. Find out missing data by counting cells (using formular: =COUNT(B3:B119)); missing data should be coded as blanked in excel. 9. Use the COUNTA function to count cells that contain values input (=COUNTA(B3:B119)) 10. Find out outlier mistakes by sorting each column; check Max and Min of data 11. Coding information for SPSS: make...
Physical Review Letters, 1971
That this twosided excitation merely enhanced sensitivity rvithout distorting the spectra via tra... more That this twosided excitation merely enhanced sensitivity rvithout distorting the spectra via transmission effects was checked by making a cavity in which a thicker potassium plate formed a conventional end wall.