Fast time-reversible synchronization of chaotic systems.

Synchronization of nonlinear systems is a crucial problem in many applications, including system identification, data forecasting, compressive sensing, coupled oscillator topologies, and neuromorphic systems. Despite many efficient synchronization techniques being developed, there are some unresolved issues such as fast and reliable synchronization using short or noisy fragments of available data. In this paper, we use time-reversible integration to obtain a synchronization technique as a generalization of the well-known Pecora-Carroll method.

Magnetic Flux Sensor Based on Spiking Neurons with Josephson Junctions.

Josephson junctions (JJs) are superconductor-based devices used to build highly sensitive magnetic flux sensors called superconducting quantum interference devices (SQUIDs). These sensors may vary in design, being the radio frequency (RF) SQUID, direct current (DC) SQUID, and hybrid, such as D-SQUID. In addition, recently many of JJ's applications were found in spiking models of neurons exhibiting nearly biological behavior.

Synthesis under Normal Conditions and Morphology and Composition of AlF Nanowires.

AlF has interesting electrophysical properties, due to which the material is promising for applications in supercapacitors, UV coatings with low refractive index, excimer laser mirrors, and photolithography. The formation of AlF-based nano- and micro-wires can bring new functionalities to AlF material. AlF nanowires are used, for example, in functionally modified microprobes for a scanning probe microscope.

Evidence of internal structure of the transactional eHealth literacy among Vietnamese youth: An instrument validation study.

Background: The progression into the Digital Age has brought an array of novel skill requirements. Unlike traditional literacy, there are currently few measures that can reliably measure eHealth literacy. The Transactional Model of eHealth Literacy and subsequent Transactional eHealth Literacy Instrument may provide a feasible option for measuring eHealth literacy.

Association of Individual and Neighborhood Characteristics to Problematic Internet Use among Youths and Adolescents: Evidence from Vietnam.

Introduction: This study aimed to determine latent profiles from the Problematic Internet Use Questionnaire Short Form-6 (PIUQ-SF-6) score of Vietnamese youths and adolescents, which supports the diagnosis of problematic internet use among a large sample size. Moreover, it also explored factors that affect each latent profile of the PIUQ-SF-6 score among participants.

Methods: A sample of 1477 Vietnamese people, aged 14 to 24, across five provinces participated in the study.

Associations between parent-child relationship, self-esteem, and resilience with life satisfaction and mental wellbeing of adolescents.

Purpose: Mental wellbeing and life satisfaction play an important role in the development of adolescents, yet factors potentially influencing these states have not been sufficiently studied, especially in Vietnam. This study aims to fill the research gaps by exploring the associations of the parent-child relationship, self-esteem, and resilience on the mental wellbeing and satisfaction with life of adolescents.

Methods: A cross-sectional study was conducted from June to July 2020 on 1,023 adolescents from 10 to 18 years old living in Vietnam.

Ensuring Population Health in the Era of Aging in Vietnam: Policy Review and Factors Associated with Intentions of Childbearing before the Age of 30 among Youths.

Delayed childbearing has become a concern among policymakers across the world. In Vietnam, population policies have been adjusted to cope with this issue. In 2020, Decision 588/QD-TTg was ratified to encourage people to marry and give birth before the age of 30.

Protecting mental health of young adults in COVID-19 pandemic: Roles of different structural and functional social supports.

Background: Concerning rates of psychological disorders are increasingly recognized in young adults during the COVID-19 pandemic. This study aimed to examine the associations of different structural and functional social supports on depression, anxiety, and stress among young adults in Vietnam.

Methods: An online cross-sectional study was performed on 236 respondents aged 16 to 30 years in Vietnam from June to July 2020.

Sensitivity Optimization and Experimental Study of the Long-Range Metal Detector Based on Chaotic Duffing Oscillator.

Sensors based on chaotic oscillators have a simple design, combined with high sensitivity and energy efficiency. Among many developed schemes of such sensors, the promising one is based on the Duffing oscillator, which possesses a remarkable property of demonstrating chaotic oscillations only in the presence of a weak sine wave at the input. The main goal of this research was to evaluate the maximal sensitivity of a practically implemented metal detector based on the Duffing oscillator and compare its sensitivity with conventional sensors.

Parent-Child Relationship Quality and Internet Use in a Developing Country: Adolescents' Perspectives.

Objective: The goal of the study was to explore the relationship between parent-children relationships related to using the internet among kids and potentially associated factors.

Materials And Methods: A sample of 1.216 Vietnamese students between the ages of 12 and 18 agreed to participate in the cross-sectional online survey.

Structural and Parametric Identification of Knowm Memristors.

This paper proposes a novel identification method for memristive devices using Knowm memristors as an example. The suggested identification method is presented as a generalized process for a wide range of memristive elements. An experimental setup was created to obtain a set of intrinsic I-V curves for Knowm memristors.

A reliable chaos-based cryptography using Galois field.

Chaos-based image encryption schemes have been extensively employed over the past few years. Many issues such as the dynamical degradation of digital chaotic systems and information security have been explored, and plenty of successful solutions have also been proposed. However, the impact of finite precision in different hardware and software setups has received little attention.

Do inequalities exist in housing and working conditions among local and migrant industrial workers in Vietnam? Results from a multi-site survey.

Background: While internal migrants in Vietnam have been a key driving force in the country's rapid economic development, they also face many vulnerabilities. Our study seeks to explore possible inequalities in housing and working conditions between local and internal migrant industrial workers in Vietnam.

Methods: Cross-sectional surveys were conducted with 1200 industrial workers in four regions of Vietnam.

Cross-cultural adaptation and measurement properties of Youth Quality of Life Instrument-Short Form (YQOL-SF) in a developing South-East Asian country.

This study was performed to evaluate the measurement properties of Youth Quality of Life-Short Form (YQOL-SF) in assessing the quality of life (QOL) among general youths in Vietnam. An online cross-sectional study was conducted to validate the YQOL-SF. Factor analysis (including exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) was utilized to determine the factorial structure of this tool.

A Note on the Reproducibility of Chaos Simulation.

An evergreen scientific feature is the ability for scientific works to be reproduced. Since chaotic systems are so hard to understand analytically, numerical simulations assume a key role in their investigation. Such simulations have been considered as reproducible in many works.

Some Remarks about Entropy of Digital Filtered Signals.

The finite numerical resolution of digital number representation has an impact on the properties of filters. Much effort has been done to develop efficient digital filters investigating the effects in the frequency response. However, it seems that there is less attention to the influence in the entropy by digital filtered signals due to the finite precision.

Changes in quality of life and its associated factors among illicit drug users in Vietnamese mountainous provinces: a 12-month follow-up study.

Background: Sustainability of methadone maintenance treatment (MMT) program involves regularly assessing its impact on health and social outcomes of drug users in different settings, particularly in disadvantaged areas. In this study, we evaluated the change in quality of life (QoL), and identified associated factors amongst drug users over the course of 12-month MMT in Vietnamese mountainous provinces.

Methods: We conducted a longitudinal study among patients from 6 MMT clinics in three mountainous provinces of Vietnam.

Patterns of Risky Sexual Behaviors and Associated Factors among Youths and Adolescents in Vietnam.

Youths and adolescents are vulnerable to HIV/STIs from unprotected sex. Promotion of young population's awareness about risky sexual behaviors is essential to develop contextualized interventions. A cross-sectional study was conducted in five Vietnamese provinces to document current attitudes and practices regarding sexual behaviors among youths.

Perception and Attitude about Child Sexual Abuse among Vietnamese School-Age Children.

Child sexual abuse has become a significant public health concern in Vietnam in recent years, and the likelihood of being abused could be prevented by increasing the awareness of sexual abuse and self-protection skills among children. However, little is known about the perception and attitude of schoolchildren toward this issue in Vietnam. This study aimed to evaluate the knowledge and attitude of school-age children toward child sexual abuse and the risk factors affecting their knowledge and attitude.

Chaotic Oscillators as Inductive Sensors: Theory and Practice.

Engineering solutions based on dynamical chaos may improve the characteristics of various sensors such as metal detectors, salinometers, optical and magnetic field sensors, and so on. In this study, we investigated the possibility of creating inductive sensors based on Sprott chaotic oscillators with a planar printed circuit board inductive coil. The electric circuit of each sensor was obtained by merging two parts, namely, a harmonic oscillator and a nonlinear filter.

Changes in Substance Abuse and HIV Risk Behaviors over 12-Month Methadone Maintenance Treatment among Vietnamese Patients in Mountainous Provinces.

Methadone maintenance treatment (MMT) programs have been used worldwide to reduce the number of drug users and for HIV prevention; however, evidence of their effectiveness in mountainous areas is limited. This study aimed to identify changes in substance abuse and sexual practices among MMT patients after treatment in three Vietnamese mountainous provinces. A survey on risk behaviors was conducted among 300 drug users in six MMT clinics prior to and following one year of MMT.

Image encryption based on the pseudo-orbits from 1D chaotic map.

Chaotic systems have been extensively applied in image encryption as a source of randomness. However, dynamical degradation has been pointed out as an important limitation of this procedure. To overcome this limitation, this paper presents a novel image encryption scheme based on the pseudo-orbits of 1D chaotic maps.

The Effects of Padé Numerical Integration in Simulation of Conservative Chaotic Systems.

In this paper, we consider nonlinear integration techniques, based on direct Padé approximation of the differential equation solution, and their application to conservative chaotic initial value problems. The properties of discrete maps obtained by nonlinear integration are studied, including phase space volume dynamics, bifurcation diagrams, spectral entropy, and the Lyapunov spectrum. We also plot 2D dynamical maps to enlighten the features introduced by nonlinear integration techniques.