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In recent years, the rural agricultural economy in Vietnam has experienced outstanding shifting progress. The paper focuses on analyzing and evaluating an overview of the agricultural economy in Vietnam in the context of global climate change and global integration during industry 4.0. The results show that many advanced and modern models of association and cooperation which are effective in agriculture and rural areas have been applied to increase production efficiency. Science and technology applied to agriculture will increase the value of the agricultural sector in Vietnam. The innovations and prosperity of agricultural infrastructure combined with the implementation of the national scheme on restructuring agricultural sectors oriented to added value increase and sustainabe development will lead to a sustainable and climate adapted agriculture.

Renewable Energy Sources (RES) are the energy sources of the future. However, RES have negative impacts on system's frequency stability because of their intermittency and low inertia characteristics. While intermittency property results in power balance in the system, which is reason for frequency variation, low inertia characteristic influences frequency change such as Rate of Change of Frequency, the minimum and maximum values of the frequency. This paper focuses on these influences of RES on frequency variation when a power imbalance occurs in the system according to mathematical theory. The results obtained show similarities with studies using simulation tools or events occurring in operational practice.

This paper presents the experimental results of researching on plastic shrinkage (plastic deformation) and the effect of curing methods on the process of plastic shrinkage at the early stages when self-compacting concrete (SCC) starts setting and develops the strength. The experiments were carried out in two typical climatic conditions in Vietnam which are humid and dry. The experiments were conducted with two typical water/powder ratios of 0.3 and 0.35 and four cases of curing methods which are nylon membrane, watering, no-curing and soaking in water (the standard condition). Besides, the influences of plastic shrinkage at the early stages on strength development and occurrence of surface cracking of SCC were also investigated. The conclusions were drawn about the plastic deformation process and the curing method that might minimize plastic shrinkage of SCC, control surface cracking early, and ensure the quality and strength of SCC in the hot and humid climatic condition of Vietnam. Keywords: plastic shrinkage; self-compacting concrete; hot and humid climate; hardening process.

Computer programming is basic knowledge in the digital age and becoming an critical subject during recent years. However, learning to programme is not an easy topic as supported by many researchers. During the development of information technology, many online learning systems have been developed and proven their positive effect on students learning. However, few studies have geared toward supporting its use in programming courses with peer-interaction. Therefore, this study aimed to develop an online learning system named Peer-Interaction Programming Learning System. The system was developed and being used by many programming classes both in Vietnam and Taiwan. In this paper, we reported on the design of the system and its user interface, discussed our motivation and underlying teaching philosophy.

In recent years, the authors have proposed a number of Nonhomogeneous Poisson process (NHPP) software reliability growth models (SRGMs) to analyse and measure the growth of software reliability during production process. This study works with a mathematics methodology to evaluate and then rank some basic NHPP SRGMs. Characteristics of ranking are: the fit of calculated occurrence failure times with real occurrence failure times; and the fit of a predicted time of the next failure with a real one. From a set of individual measures, the methodology mentioned will be deployed. The implementation of some SRGMs with several real data sets confirms that the ranking of SRGMs depends on the data sets.

Reliability is the chief quality that one wishes for in anything. Reliability is also the main issue with computer systems. One of the purposes of system reliability analysis is to identify the weakness in a system and to quantify the impact of component failures. However, existing reliability prediction approaches for component-based software systems are limited in their applicability because they either neglect or do not support modeling explicitly several factors like error propagation, software fault tolerance mechanisms. In this paper, we evaluate reliability prediction of component-based system and fault tolerance structures technique by applying Pham Nordmann Zhang (PNZ) model, one of the best models based on non homogeneous Poisson process. Our approach uses a reliability modeling schema whose models are automatically transformed by a reliability prediction tool into PNZ models for reliability predictions and sensitivity analyses. Via these our case studies, we demonstrate its applicability and introduce how much reliability of software system can be improved by using fault tolerance structures technique.

金沢大学医薬保健研究域医学系, To identify hepatitis C virus (HCV) transmission routes among injection drug users in Northern Vietnam, plasma samples were collected from 486 drug users in Hai Phong. Plasma viral RNA was extracted from 323 (66.5%) samples that were positive for anti-HCV antibodies. Portions of the HCV 5′- untranslated (5′UTR)-Core and NS5B genes were amplified by reverse-transcriptase polymerase chain reaction, sequenced directly, and genotyped in 194 and 195 specimens, respectively. Both regions were genotyped in 137 specimens. In the 5′UTR-Core region, genotype 6a was predominant (32.5%), followed by genotype 1a (23.7%), genotype 1b (20.6%), and genotype 6e (14.4%). In the NS5B region, genotype 1a was predominant (42.6%), followed by genotype 1b (24.1%), genotype 6a (14.4%), genotype 3b (7.2%), and genotype 6e (5.1%). Of the 137 specimens with both regions genotyped, 23 (16.8%) showed discordant genotyping results between the two regions, suggesting possible recombination and/or dual infection. Phylogenetic analysis revealed close associations between Hai Phong strains and strains from Southern China: the Yunnan province for genotype 3b; the Guangxi province for genotype 6e; the USA for genotype 1a; and Southern Vietnam for genotypes 1a and 6e. The human immunodeficiency virus (HIV) infection rate among HCV-infected injection drug users was 52.6-55.4% and did not differ significantly by HCV genotype. Most drug users infected with HIV-1 [98.8% (171/173)] were co-infected with HCV. These results suggest multiple routes of HCV transmission among injection drug users in Northern Vietnam that may also be HIV transmission routes. © 2010 Wiley-Liss, Inc.

Local icosahedral order and thermodynamics of amorphous Fe have been analyzed in detail for models containing 3000 atoms, which were obtained by the molecular dynamics (MD) method. Models were obtained by cooling from the melt. Local order in models has been analyzed by using the technique proposed by Honeycutt and Andersen; we found an existence of icosahedral order in the system. Moreover, structural properties of models were also studied via radial distribution function (RDF), static structure factor, mean atomic distances, coordination number and bond-angle distributions. Glass transition temperature, heat capacity and potential energy of the system were found in addition to the evolution of structure and mean-squared displacement (MSD) of atoms upon cooling from the melt toward the glassy state. We found the glass transition temperature of simulated liquid Fe via temperature dependence of potential energy and it is close to that observed previously in the literature, i.e. T g ≈1070 K. Calculations showed that structural properties of amorphous Fe models with the Pak–Doyama interatomic potential agreed well with the experimental data.

Software reliability modelling (SRM) is a mathematics technique to estimate some measures of computer system that relate to software reliability. One group of existing models is using non-homogeneous Poisson process (NHPP) whose fault-number and failure-rate are constant or time-dependent functions. A few studies have been manipulated S-shaped curve to construct their models. However, those works remain some limitations. In this study, we introduce a new model that is based on a generalised S-shaped curve and evaluate it by real data set. After installing it in real code of Matlab and using MLE method to estimate parameter with a range of initial solution, we prove that our model converge to the most basic model of NHPP group, Goel-Okumoto model.

Although the quality of computer software consists of many different aspects, the security and the optimization are by far the most important metrics for estimating quality of software systems. The security ensures that application will work correctly and the optimization reduces the amount of resources needed: computation, memory, size of code, etc. Those techniques can be done by applying rules in abstract syntax tree, a tree representation of the abstract syntactic structure of source code. However, the process to optimize code often makes negative effect to the security of program. This work studies about applying rules in abstract syntax tree in Java and its effect on code optimization and secure programming problems.

This paper presents a new variable-length, multiplierless Fast Fourier Transform (FFT) hardware implementation. The proposed implementation handles with 16, 64 and 128 point FFT frames. The architecture is designed based on Single-path Delay Feedback (SDF) scheme which implements the mixed radi×2, 22 FFT algorithms. In order to improve the performance, the complex multipliers are replaced by simpler and faster units which use only shift and addition/subtraction operations. As consequence, we obtain twofold increase in the speed.

We evaluated the prevalence and profile of antiretroviral treatment (ART)-associated resistance mutations among HIV-1 strains in northern Vietnam by genotypically analyzing strains isolated from ART-naive individuals in Hai Phong, a city in which HIV-1 is highly prevalent. Plasma samples were collected from injecting drug users (IDU, n = 760), female sex workers (FSW, n = 91), seafarers (n = 94), pregnant women (n = 200), and blood donors (n = 210), and screened for HIV-1 antibodies. Plasma viral RNA was extracted from HIV-1-positive samples, amplified by reverse transcriptase (RT)-PCR of protease and RT genes, and analyzed for genotypes and ART-associated resistance mutations. HIV-1 prevalence among IDU, FSW, seafarers, pregnant women, and blood donors was 35.9%, 23.1%, 0%, 0.5%, and 2.9%, respectively. Phylogenetic analyses revealed that the most prevalent HIV-1 subtype was CRF01_AE (98.3%), similar to strains prevalent in southern China. Four (1.4%) subtype B strains and one (0.3%) unique recombinant between subtypes B and C were also identified. We found protease inhibitor-associated major resistance mutations in one of the 294 cases analyzed (0.3%; mutation M46I). We found RT inhibitor-associated major resistance mutations in 7/273 cases (2.6%; one occurrence each of L74I, M184I, and K219E; three cases of K103N; and two cases of G190E). One CRF01_AE strain harboring a protease codon 35 insertion was first identified in Vietnam. Thus, monitoring of drug-resistant HIV-1 and establishment of a database are required for the proper selection of ART in Vietnam.