241 research outputs found
Establishing an Assessment Criteria System for Architectural Heritage of Colonial Educational Buildings in Hanoi
A number of educational buildings were built up by the French in Hanoi during their dominance. Most of these buildings still exist in the downtown area and have become an integral part of the valuable heritage, and their preservation is increasingly imperative. To preserve and promote more efficiently the values of the colonial building heritage assets, there is a need of a set of criteria for an assessment and classification. This paper presents the development of an assessment criteria system for the architectural heritage of colonial educational buildings in Hanoi. According to the proposals, colonial educational buildings can be classified into three groups of Special Value, Notable Value, Average Value. A set of criteria including factors related to both the internal and external values of these buildings have been proposed and validated with expert judgements. Each criterion then is incorporated with a set of scores showing the value it can bring to a colonial educational building to be assessed. The set of criteria and their scores can be used by the city authority to establish regulations to preserve and promote heritage values of the colonial educational buildings in Hanoi
Factors affecting the flipped classroom in the educational context of Vietnam
In the context of the implementation of the 2018 General Education Program, teachers are required to implement a teaching model oriented to the development of students’ quality and competence. Teachers are encouraged to adapt the flipped classroom model of teaching in schools as its advantages are suitable for novel teaching strategies. This study focuses on analyzing factors affecting the application of this model in the teaching and learning process by collecting feedback from 351 teachers from various cities in Vietnam. The questionnaire included Likert-type questions analyzed by IBM SPSS Statistics version 20 for quantitative analysis and an open question for qualitative analysis with context and personal information. The research-oriented factors focus on the group of potential internal factors (perception, proficiency, desire and readiness of teachers) and the group of external factors (infrastructure, facilities and support resources, training programs). The results showed that those factors include the school’s infrastructure and information communication technology (ICT) condition, the teacher’s ICT competence as well as competence-related teaching and assessment methodologies and the students’ internet access conditions. Finally, the study offers suggestions on how to apply this model in teaching practice to meet the requirements of educational innovation in Vietnam
Trends in, projections of, and inequalities in non-communicable disease management indicators in Vietnam 2010–2030 and progress toward universal health coverage : a Bayesian analysis at national and sub-national levels
Background: Movement towards Universal Health Coverage (UHC) can improve health services, risk factor management, and inequality in non-communicable diseases (NCD); conversely, prioritizing and monitoring NCD management can support pathways to UHC in resource-limited settings. We aimed to estimate trends in NCD management indicators in Vietnam from 2010, and projections to 2030 at national and sub-national levels; compute the probability of reaching UHC targets; and measure inequalities in NCD management indicators at demographic, geographic, and socio-economic levels. Methods: We included data of 37,595 households from four nationally representative surveys from 2010. We selected and estimated the coverage of NCD health service and risk management indicators nationally and by six sub-national groups. Using Bayesian models, we provided trends and projections and calculated the probability of reaching UHC targets of 80% coverage by 2030. We estimated multiple inequality indices including the relative index of inequality, slope index of inequality, and concentration index of inequality, and provided an assessment of improvement in inequalities over the study period. Findings: Nationally, all indicators showed a low probability of achieving 2030 targets except sufficient use of fruit and vegetables (SUFV) and non-use of tobacco (NUT). We observed declining trends in national coverage of non-harmful use of alcohol (NHUA), sufficient physical activity (SPA), non-overweight (NOW), and treatment of diabetes (TOD). Except for SPA, no indicator showed the likelihood of achieving 2030 targets at any regional level. Our model suggested a non-achievement of 2030 targets for all indicators in any wealth quintile and educational level, except for SUFV and NUT. There were diversities in tendency and magnitude of inequalities with widening gaps between genders (SPA, TOD), ethnic groups (SUFV), urban-rural areas (TOH), wealth quintiles, and educational levels (TOD, NUT, NHUA). Interpretation: Our study suggested slow progress in NCD management at the national level and among key sub-populations in Vietnam, together with existing and increasing inequalities between genders, ethnicities, geographic areas, and socioeconomic groups. We emphasised the necessity of continuously improving the healthcare system and facilities, distributing resources between geographic areas, and simultaneously integrating economic, education, and gender intervention and programs. Funding: None. © 2022 The Author(s
NONLINEAR CHARACTERISTICS OF SQUARE SOLID-CORE PHOTONIC CRYSTAL FIBERS WITH VARIOUS LATTICE PARAMETERS IN THE CLADDING
Nonlinear characteristics of fused silica, solid-core photonic crystal fibers (PCFs) with a square array of air holes are studied numerically. We present a novel design that emphasizes the difference in air hole diameters in the photonic cladding. These PCFs have the advantages of flat dispersion, high nonlinearity, and low attenuation. Based on simulation results, three optimal structures, denoted #F1, #F2, and #F3, having anomalous and all-normal dispersions in the near-infrared range are selected to investigate characteristic properties at the pump wavelength. Such PCFs open up many possibilities for nonlinear optical applications, especially supercontinuum generation
INFLUENCE OF STRUCTURAL PARAMETERS ON OPTICAL CHARACTERISTICS OF PHOTONIC CRYSTAL FIBERS WITH CIRCULAR LATTICE
We demonstrate in this study that near-zero, ultra-flattened chromatic dispersion can be achieved over a wide range of wavelengths in photonic crystal fibers (PCFs) by means of slight variations in the geometrical parameters of the cladding. To do that, a new solid-core circular PCF design with various air hole diameters and lattice constants is presented, and the design features are numerically analyzed in detail. After 40 simulations, we determined three structures that possess optimal dispersion with the following lattice constants (Ʌ) and filling factors for the first ring (d1/Ʌ): Ʌ = 0.8 µm, d1/Ʌ = 0.45 for #F1, Ʌ = 0.9 µm, d1/Ʌ = 0.45 for #F2, and Ʌ = 1.0 µm, d1/Ʌ = 0.45 for #F3. High nonlinearity and low attenuation are outstanding features of our model. With these advantages, the proposed fibers are targeted for smooth flat broadband supercontinuum generation for near-infrared applications
Dispersion and nonlinearity properties of small solid-core photonic fibers with As2Se3 substrate
Characteristics of As2Se3 photonic crystal fibers (PCFs) with a solid-core and small-core diameter are numerically investigated in the long-wavelength range (from 2 to 10 μm). A full modal analysis and optical properties of designed photonic crystal fibers with lattice constant Λ and filling factor d/Λ are presented in terms of chromatic dispersion, effective refractive index, nonlinear coefficients, and confinement loss. The simulation results show that a high nonlinear coefficient of 4410.303 W–1·km–1 and a low confinement loss of 10−20 dB·km–1 can simultaneously be achieved in the proposed PCFs at a 4.5 μm wavelength. Chromatic dispersions are flat. The values of dispersion increase with increasing filling factor d/Λ and decrease with the increase in lattice constant Λ. In particular, some chromatic dispersion curves also cut the zero-dispersion line at two points. The flat dispersion feature, high nonlinearity, and small confinement loss of the proposed photonic crystal fiber structure make it suitable for supercontinuum
Comparison of dispersion characteristics of hollow-core photonic crystal fibers filled with aromatic compounds
In this paper, hollow-core photonic crystal fibers (PCFs) infiltrated with benzene and nitrobenzene are designed and investigated. Their dispersion characteristics are numerically simulated. The results show that using the aromatic-compounds-filled hollow core of PCFs makes dispersion curves flat. In addition, the dispersion curves approach the zero-dispersion line closer than previously published dispersion curves of PCFs with toluene, thus significantly improving the supercontinuum generation to create the ultra-flat spectrum expansion
Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio
Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications
Applied bioinformatics tools for analysis of Microrna-214 expression and prediction of its potential targets genes in Nasopharyngeal carcinoma
miRNA (microRNA) are short RNA molecules in length from 20 to 24 nucleotides that have been shown to play an important role in regulating gene expression in many different types of human cancer. Meanwhile, miRNA-214 is one of the known miRNAs involved in the formation of nasopharyngeal carcinoma (NPC) through overexpression that promotes proliferation and development of cancer cells. However, in Vietnam, the study of miR-214 related to NPC has not been conducted yet. With the aims to develop the further studies of miR-214 on NPC in Vietnamese patients, in this initial study, we conducted the analysis of miR-214 expression in previous publications, as well as the prediction of miR-214 potential target genes, which involved in many cellular pathways. Here we applied bioinformatics tools to predict miRNAs and their targets, and discuss the role of miR-214 in the context of human cancers. As the results, miR-214 acted as the oncogenic roles in NPC, relevanted to many pathways, such as cell proliferation, apoptosis, metastasis and invasion through the its target genes LTF, Bim, Bax, LINC0086, etc. In conclusion, the use of computional approaches facilitate the further experimental validation of miRNAs in general, particularly miR-214, in Vietnamese NPC patients
Real-time Damper Force Estimation for Automotive Suspension: A Generalized H2/LPV Approach
The real-time knowledge of the damper force is of paramount importance in controlling and diagnosing automotive suspension systems. This study presents a generalized H2/LPV observer for damper force estimation of a semi-active electro-rheological (ER) suspension system. First, an extended quarter-car model augmented with the nonlinear and dynamical model of the semi-active suspension system is written into the quasi-LPV formulation. Then, the damper force estimation method is developed through a generalized H2/LPV observer whose objective is to handle the impact of unknown road disturbances and sensor noise on the estimation errors of the state variables thanks to the H2 norm. The measured sprung and unsprung mass accelerations of the quarter-car system are used as inputs for the observer. The proposed approach is simulated with validated model of the 1/5-scaled real vehicle testbed of GIPSA-lab. Simulation results show the performance of the estimation method against unknown disturbances, emphasizing the effectiveness of the damper force estimation in real time
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