ABSTRACT. We applied survival analysis techniques to study exocytosis events in human beta-cells. First, a marginal Cox model with clusters (our cells) is applied to Exocytosis data from TIRF imaging, after having processed to achive the numerical data and to remove noise. Then a semi-parametric spatial survival model is proposed to account for the possible spatial correlation within each cluster. In regard of the latter, a parametric model is specified for the spatial correlation function. An MCEM algorithm is implemented for parameter estimates.

ABSTRACT. A well-balanced high-order scheme for shallow water equations with variable topography and temperature gradient is constructed. This scheme is of van Leer-type and is based on exact Riemann solvers. The scheme is shown to be well-balanced as it can capture almost exactly stationary waves. Numerical tests show that the scheme gives a much better accuracy than the Godunov-type scheme and can work well even in the resonant regime. Wave interaction problems are also tested where the scheme possesses a good accuracy. It turns out that the superbee limiter can provide us with more accurate approximations than van Leer's limiter.

ABSTRACT. We study the amplitude dynamics of a single flat-top soliton and fast collisions of two flat-top solitons in a system of coupled cubic-quintic nonlinear Schrödinger equations with the generic weak nonlinear loss. We develop a perturbative method to derive the theoretical expression for the collision-induced amplitude shift in a fast collision of two solitons in both one-dimensional (1D) and two-dimensional (2D) nonlinear optical media. The perturbative technique is mainly based on the energy balance calculations of the perturbed solitons due to the nonlinear loss. Our analytic predictions are confirmed by the numerical simulations with the corresponding perturbed coupled nonlinear Schrödinger equations using the split-step Fourier method.

ABSTRACT. This talk presents algorithms for verifying isomorphism of Lie algebras. The key point is that we use the so-called triangular decomposition of polynomial systems as well as semi-algebraic systems.

ABSTRACT. It is well-known that all the coadjoint orbits of 4-dimensional real Diamond group as well as any Heisenberg Lie group are orbits of dimension zero or maximal dimension. In general, a (finite dimensional) real solvable Lie group is called an MD-group if its coadjoint orbits are zero-dimensional or maximal dimensional. The Lie algebra of an MD-group is called an MD-algebra. In 1995, D. Arnal and M. Cahen classified all MD-groups whose nontrivial coadjoint orbits are 2-dimensional. Nearly, in 2019, M. Goze and E. Remm determined a subclass of MD-algebras whose nontrivial coadjoint orbits are 4-dimensional. In this paper, we give a complete classification of MD-algebras such that the maximal dimension of the coadjoint orbits is 4 or 6.

ABSTRACT. Nosocomial infections, particularly postoperative infection, are common following surgery due to various risk factors that are contributing like age, duration of operation, number of persons in the operating theatre, the general condition of the operating room... The nosocomial infections prolonged the lengths of hospitalization, developed multi-organ dysfunction, and increased mortality. The conventional laminar airflow systems in operating required huge installation and renovation costs. It is not suitable for the Low-Middle Income Countries. This paper presents research on the view toward the realization of a mobile laminar airflow system for preventing the contamination of airborne pathogens by protecting the surgical site area as well as the instrument table with low-cost. Simulations with computational fluid dynamics (CFD) were conducted to optimizing system design. The simulation results were examined and evaluated in this paper. With this proposed mobile laminar airflow system, the sterile conditions could be created immediately wherever you need it.

ABSTRACT. Development a low-cost electrical impedance tomography system for non-invasively detecting abnormal in breast tissue - Phantom study-

ABSTRACT. Typical attention to the face of an interactive partner is an early hallmark of autism spectrum disorder (ASD). The eye tracker is a visual tool to estimate the subject’s gaze, and the choice of visual stimuli plays an essential role in studies of early ASD diagnosis using eye-tracking methods. Although many studies demonstrating relations between ASD and visual attention in early infancy were conducted, the safety of these methods should be improved, and real interactive contexts should be implemented. This study focuses on improving eye safety and solving the limitations of previous eye-tracking methods in terms of an interactive context. This study proposes the general descriptions of a new eye-tracking method: mirror-eye tracker system via image formation of a plane mirror, perspective projection geometry, and Guestrin’s general theory of remote gaze estimation using the Pupil Center Cornea Reflection (PCCR) technique.

ABSTRACT. In this study, the numerical computation is used to develop a physical model which represents all important features of the Autonomous Underwater Vehicle’s (AUV) shape using the finite element methods. Because the shape of the AUV is an important factor in determining the application and the capability of the vehicle, investigating the effect of environment on this profile is needed. This paper gives an illustration about using Computational Fluid Dynamics (CFD) to investigate the effect of fluid flow on the AUV’s profile at different velocities. The results obtained from the numerical computation demonstrate some of the hydrodynamic values to the AUV’s shape such as drag force and stress. It is necessary for optimizing the design of an AUV. When the AUV moves, the maximum pressure occurs at the nose of an AUV.

ABSTRACT. In this research, a study on damage behavior of porous concrete was conducted. Based on the phase field theory and the generation process based upon Monte Carlo’s simulation method, we construct a numerical procedure to solve complex damage thermodynamic problems. The phase field variable obtained can be used to model crack behavior within porous concrete structure. Some factors that affect the results are discussed to make the predictions more accurate for the case of porous concrete material. Illustrations of applications are provided in examples to show the usefulness of the approach.

ABSTRACT. Auxetic materials possess the unique property of negative Poisson’s ratio (NPR). Such a material can be made by the repetition of patterns that exhibit the NPR property. On other words, if a unit cell in the structure has NPR property, then the whole structure is effectively auxetic. In this research, the NPR unit cell is determined by topology optimization. With constraint on volume fraction of the unit cell, the homogenized Poisson’s ratio of the cell is minimized. Homogenization of Poisson’s ratio is conducted using energy method with consideration of periodic boundary conditions. The performance of the proposed algorithm is demonstrated by several two-dimensional numerical examples. The effective auxetic property of the obtained designs is verified by finite element simulations.

ABSTRACT. The aim of this paper is to estimate the bulk modulus of composite containing spherical inclusion surrounded by an interphase whose elastic properties vary with radius. Based on the sphere assemblage model and the differential substitution scheme, the differential equation for the bulk modulus is established. The effective bulk modulus of the material are predicted by numerical integration. The effect of interphase zone is also investigated.

ABSTRACT. This paper presents the design of a test rig for structural static load testing of small horizontal wind turbine blades. It is the next step after the success of the DeVie project, a join-research project to boost the wind energy know-how between Germany and Vietnam. According to the IEC-61400-23 standard for full-scale structural testing of rotor blades, and based on existing facilities of HCMUT, especially the aerospace engineering lab. and the engineering mechanics lab., we propose a prototype of a test-rig for structural static load testing of rotor blades. And a rotor blade of 4 meters in length, manufactured by China, is used in a case study of our structural static-load test-rig. The obtained results will be compared with the reverse engineering this rotor blade with QBlade/FAST in the same blade loading

ABSTRACT. The input impedance of a regulated cascode cross couple amplifier is derived. The frequency response of the input impedance polynomial form can be plotted with MATLAB. From the polynomial form of the input impedance of the proposed circuit, it can be transformed by substitute complex frequency s with into the polynomial form equation. After that, this function can be grouped into a symbolic real and a symbolic imaginary form. The next step in derivation is to multiply this function with a complex conjugate function of the symbolic complex form of the input impedance. The last step is to plot a real and an imaginary part as a function of the input frequency so that the power amplifier can be matching with the various matching circuit according to the condition of the maximum power transfer

ABSTRACT. Nowadays, smart medicine has been the trend of health care. Diagnostic, treatment and health monitoring become more and more simple and faster. Besides, the need for the convenience of doctors in the surgery room has been increased. In fact, infection is an invisible threat that can appear in any steps of surgery, lead to many problems in the postoperative period. Therefore, sterilization and asepsis are the first priorities, especially in operating theaters where sterile conditions are strictly required. Surgeons, when washing their hands, cannot touch the valve (where bacteria accumulate a lot), to ensure the sterile condition of tools used for surgical operation. Today, popularity in the Vietnamese market is knee operated hand washing sink. Although the price is cheap, the mechanism is simple but causing inconvenience for users. In the period of industrialization and automation, some manufacturers have produced automatic medical handwashing sinks with different materials and models, bringing modernity and convenience for surgeons and ensure sterile conditions in the operating room, but the price is still quite high. This project will inherit the advantages from existing models, design, and implement the model of an automatic hand-washing sink, in order to enhance the convenience and efficiency of water purification at low cost, with aesthetic and high applicability but still safe. The process of this project begins from researching general principles, designing the power unit, control unit, signal processor to researching the water treatment system (UV light and 3-level filter). In the end, assembling parts to the sink framework, we have the completed model. After that, the model has undergone a process of a test run, benchmark, and adjustment. The result of acceptance is the model guaranteed with all safety factors at reasonable prices.

ABSTRACT. To be quality assurance and high accuracy with Intensity-modulated radiotherapy (IMRT) technique, it is necessary to perform a patient-specific pre-treatment quality assurance test. There are several methods such as point dose measurement by ionization chamber and 2D plane dose measurement. In addition, the trajectory log file can be used to check the treatment plan. The accelerator stores information throughout the treatment process through a trajectory log file. The file records information including actual and planned value. The high-resolution file allow deep analysis into treatment plans delivered by Varian treatment machines. Based on the file to identify the location of errors of MLC leaves, Gantry angle errors, Collimator angles errors, Carriage errors, MU errors, and then evaluate treatment plans based on the fluence maps reconstructed from the acquired log file. The file can be used in combination with other traditional measurements to implement patient-specific quality assurance tests

ABSTRACT. The durability of a concrete structure depends strongly on its water permeability. A good understanding of transport phenomena will be useful for predicting the service life and optimizing the material design. The objective of the current study is to model the flow fields throught the concrete specimen consisting of coarse aggregates and mortar matrix. In this work, the hydraulic properties of Darcy flow, such as the velocity and pressure fields have been estimated by using boundary element method, then the effect of volume fractions of coarse aggregates on the effective permeability coefficient of concrete have been discussed. For the purpose of showing the accuracy of the boundary element method, the results obtained for the velocity and pressure fields are compared with the ones provided by the finite element method.

ABSTRACT. EEG and ECG are the two main types of bioelectrical signals in the field of human functional research. This study focuses on classifying two emotional states, stressed and relaxed, using both EEG and HRV signals. The procedure conducted on 17 healthy volunteers ages 21 to 23 years old. For stressed and relaxed stimuli, subject watch affective pictures form the NAPS pictures set and doing Mental Arithmetic Task (MAT) to exclit stress emotion interspersing with slow deep breathing (DSB). There are 35 features extracted and selected using Kendall’s Tau correlation coefficients. Features then were transformed by nlPCA to perform dimension reduction for the input of Cascade Forward Neural Network (CFNN) to classify. The result shows that some features related to the relative Alpha frequency from EEG, as well as blink rate and Entropy of HRV, are not only suited for both types of stimuli but also show a strong correlation with the target classes. The result of classifying using CFNN achieved a relatively high accuracy value of 95,96% when using both EEG and HRV together. The results when using only EEG or HRV are respectively 83,33% and 69,70% confirmed that combine these two signals did increases the accuracy for the classification.

ABSTRACT. In recent years, near-infrared (NIR) method has been developed and applied in many aspects of life, especially in dentistry. Nowadays, X-ray is not only the common method used to diagnose dental diseases but also considered as the gold standard in dentistry. However, X-rays can affect the patients’ and dentists’ health. Moreover, X-ray method is not sensitive enough for detecting early lesions such as white spot lesions. With regard to near – infrared technique, many researches have indicated that enamel is nearly transparent under near-infrared light due to its low absorption and scattering coefficients in this wavelength region. Therefore, early lesions located inside enamel layer can be observed by NIR image (780 nm – 1310 nm) due to their difference in optical properties compared to sound tooth tissue. In this study, using the NIR light optical system at 850 nm, we have collected and handled a number of tooth samples of different lesions, detected the lesions by capturing NIR images, compared diagnostic results using NIR technique with clinical examination and X-ray method, figured Cohen's Kappa coefficient using SPSS (Statistical Package for the Social Sciences) to assess the effectiveness of NIR method.

ABSTRACT. The Piper Sarmentosum is easy to find, easy to grow, easy to exploit, and also contain this ingredient and other biological properties. The leaves of Piper Sarmentosum are one of the typical uses of this herb. In the leaves, there are components that reduce effectively, highly preserved aches, and pains. Besides, thanks to the antibacterial, anti-inflammatory active substances, leaves are also highly effective at curing gynecological diseases. Our research uses laser light to work at various wavelengths interacting with the leaves in order to survey the development and bioactivity of the leaflet from which to offer the most appropriate approach to towards the maximum extraction of biological activity in practice.

ABSTRACT. We investigate the existence of a sequence solutions for a nonlinear Dirichlet problem. Under the assumptions of local superlinear and sublinear on the nonlinearity, we got a sequence of solutions approaching to infinity and zero, respectively.

ABSTRACT. In this study, the computational fluid dynamics (CFD) method is used for simulating the distributions of environmental parameters: thermal, velocity, inside an office room with air-conditioner. The model, which is seclected for analysis, is the office in Hong Kong and the time is summer. The research outputs provide useful information for designers of cooling system to build a comfortable indoor environment.

ABSTRACT. In this study, the static structrural module of the commercial computer software (ANSYS) is utilized to run simulations for stiffened panel undergoing compression and lateral pressure in order to study the buckling and post buckling behavior of it. The model of stiffened panel used in this research is made of composite materials and is widely adopted in primary aircraft structures comprising of wings and fuselages, etc. The research outputs are the effect of the lateral pressure on the stability of stiffened panel in eigenvalue analysis as well as nonlinear analysis. More particularly, the uniform distributed lateral pressure has a positive impact on enhacing the amplitude of uniaxial compression applied on the right edges of stiffened panel to occur buckling behavior, thereby they can provide engineer with useful knowledge to design the aircraft structure to ensure the highest stability of stiffened panel as possible.

ABSTRACT. The Simulative Multi-slice CT-Scanner operation software is a software that can control the operation of the system, through the scanning modes of Standard, Helical and Scanogram. In addition, the software can simulate the projection data acquisition process when the system is performing scanning operations and the process of reconstruction slice images visually. This sturdy uses C# programming language for designing the software and programed on Windows Presentation Foundation (WPF) Framework interface programming in Visual Studio, supported on Windows operating system. Refer to the operating procedure of CT-Scanner system in practice to build a suitable control algorithm for the simulation model. Using MATLAB software's built-in image reconstruction algorithm (ifanbeam), to generate Sinograms from sliced images, then save the Data sets including Sinograms and corresponding slices to a database. To visualize the process of images reconstruction and the data acquisition of the model, show each column of the images matrix of the Sinogram, taken from the data set created earlier using MATLAB. The showed column correspond to a scan angle of the gantry when the model is simulate a scanning. After showing all of the columns in the Sinogram's image matrix the gantry will finish one full rotation, the complete Sinogram of the rotation will be save to another window with the correspond reconstructed image for implementation. The process repeat the same for all the Sinogram images in the data set.

ABSTRACT. The prefabricated industrial factory is currently the most popular type of factory building because it is made of steel structures that are manufactured and pre-fabricated from the factory. Due to the advantages of the prefabricated industrial factory is low cost, fast construction time, low maintenance cost and can be easily expanded, so it is the first choice of investors instead. for ordinary industrial factory construction. The steel frame structure is firmly calculated and suitable for the use of the industrial factory, helping the investor to both save materials and satisfy space for use. However, in order to have a quality factory building, in addition to owning a team of skilled designers, the project must meet the necessary construction standards, sustainable under the impact of load, achieves structural strength to ensure the best return quality. A phenomenon is mentioned instability, the main cause of structural collapse accidents affecting property and people. In depth on this issue, this project researches and develops: NONLINEAR BUCKLING ANSYSIS OF INDUSTRIAL FACTORY STRUCTURES on Ansys Workbench software.

ABSTRACT. In recent years, the problem of noise reduction is being studied. In the paper, some models of sound attenuation will be simulated and calculated using ANSYS WORKBENCH software. By using the finite element method (FEM) for the sound wave and fluid – structure interaction (FSI), sound pressure level reduction can be calculated for the sound transmission problems. The problem of sound absorption through a duct, the problems of the sound transmission through single and double walls will be discussed in this paper. Results will be compared with results solved by Matlab software and experiment.

ABSTRACT. Welding is one of the most used methods for joining metals. The problem of distortion and residual stresses of a structure due to welding is important to control. Numerical simulations make the improvement of fabrication process and welding technology possible. Using finite element (FE) method the most important information about welded specimens can be determined such as deformed shape, residual stresses. The paper focuses on heat sources, temperature dependent material properties and the development of a thermo–mechanical analysis.

ABSTRACT. CFD (Computational Fluid Dynamics) simulations appear to be strong competitor of the wind tunnel test which required scaled model and it is really expensive and time consuming tool in designing bridges therefore there is a strong claim to replace them with CFD. Based on ANSYS Fluent and ANSYS Transient Structural with System Coupling, a fluid-structure interaction (FSI) model has been developed to investigate the flutter characteristics of a bridge deck. The flow around a bridge cross-section as well as the flow around the same cross-section with torsional motion and vertical motion. In this paper, three models of the bridge section (rectangular, fairing and spoiler) are given to calculate the aerodynamic bridge deck behavior and bridge deformation. Simulation results indicate that the rectangular section has the largest flutter, the spoiler section has the smallest flutter.

ABSTRACT. With the growing social trend, the quality of human life is also improved day by day, therefore, people are always demanding a higher quality of life. Construction is always at the forefront of the country's development. To help improve and improve the safety and efficiency of the building, one of the solutions to improve is about materials such as high bearing capacity, ductility, heat resistance, which can be widely applied and bring many economic benefits. Composite materials meet most of the practical requirements. The need to analyze composite structures has led to many studies on the mechanical behavior of this structure, including nonlinear buckling. The present research was done a finite element method analysis of plate and plate with cutout have different fiber configurations by software ANSYS APDL. Analysis was performed to research the effects of fiber direction, modeling of plate, and cause of buckling modes.

ABSTRACT. Square planform silos have not been studied as often as their circular counterparts, and relatively little detailed information exists in the literature on pressure patterns which develop on their walls. This study used a pilot-scale square planform funnel flow unstiffened steel silo with relatively flexible walls to investigate the patterns of pressures on filling, during storage and during discharge. Two different free-flowing solids, sand and pea gravel, were used. The silo was instrumented with wall pressure cells, free field cells, strain gauges and displacement devices. From the extensive collected data, some examples of measured pressures during filling and discharge are presented, together with an introduction to the effects of eccentric discharge.