Optimal control of switched capacitor banks in Vietnam distribution network using integer genetic algorithm

In distribution network, power and energy losses can be reduced by using switched capacitor banks. The capacitor banks can be switched on or off based on voltage profile or power factor or using timers. Due to variation of load, it is necessary to control the capacitor banks switching in function of load curve. This paper presents the application of an integer genetic algorithm to determine the optimal number of banks corresponding with hourly load to minimize total active power losses of distribution feeders. The problem constraints include voltage profile and heat conditions which are taken into account to the objective function by a penalty function. In this application, the structure of chromosomes is a set of numbers of the capacitor banks hourly connected to the grid. The proposed formulation is validated by a feeder. The result shows that in some cases, the active power losses at maximum compensation are greater than the ones of optimal control compensation, and the voltage reaches a higher level than the maximum voltage limit. The optimal control of switched capacitor banks can reduce power and energy losses as well as ensure maximum voltage profile within the limit

Do Corporate Social Responsibilities Support Its Financial Performance? Evidence of the Listed Firms in Vietnam

In the latest decades, corporate social responsibilities (CSR) are incrementally noticed in emerging countries regarding to the surge of globalization and the advance of social concerns. However, there exist opposing arguments on how CSR practices influence a firm’s financial performance (CFP), either in theoretical or empirical perspectives, causing many managers’ hesitation in CSR engagement. This study, therefore, examines the impacts of CSR on CFP, considering the individual effect of each CSR endeavor by using the data from listed firms’ financial statements during the period 2015-2019 and panel regression analysis methods. The findings reveal inconstant effects of different CSR activities on CFP. Specifically, a firm’s fulfillment of shareholders’ and customers’ interests contributes to raise its profitability, while its engagement in the benefits of employees and creditors causes a reduction in financial returns. Interestingly, the correlations between firms’ responsibilies towards regulators and suppliers and CFP are statistically insignificant. Furthermore, we make pairwise marginal comparisons to identify the distinctions of CSR-CFP relations across industries. The results only indicate that listed firms in Utilities sector have the lower level of CSR intensity than those in Consumer Discretionary and Consumer Staples sectors. The implications and limitations are also discussed in this study

A Study on the Impact of the Usage of Cost Information on Business Performance of Enterprises in Vietnam

Purpose: The primary objective of the research was to investigate the correlation between the utilization of cost information and business performance of enterprises in Vietnam, particularly in the context of the Covid-19 pandemic.   Design/methodology/approach: A survey was conducted, involving a sample of 380 participants consisting of CEOs, CFOs, managers, board of directors, and individuals in charge of accounting and finance departments. The study employed a structure equation model to analyze the relationship between the use of cost information and business performance.   Findings: The study revealed a significant and positive impact of cost information utilization on business performance among the surveyed enterprises in Vietnam. Additionally, the study provided recommendations for enterprises in Vietnam on how to make use of cost information for various purposes, including planning, evaluating, decision-making, and cost control, to optimize their business performance.   Research, Practical & Social implication: The study's results suggest that utilizing cost information effectively can lead to improved business performance and may provide valuable insights for Vietnamese enterprises on how to navigate the challenging and competitive post-Covid-19 economic environment.   Originality/value: The research employed a structural equation modeling (SEM) approach, and a test for univariate normality demonstrated an outstanding critical skewness ratio value. Furthermore, the kurtosis indicated that the data followed a normal distribution, making it suitable for analysis. Since SEM employs rigorous criteria to evaluate model fit, it can be inferred that the measurement model exhibited a high level of fit. The findings affirm the beneficial impact of utilizing cost information on business performance and offer significant recommendations for Vietnamese businesses in the current post-COVID era

The Impact of Personal Financial Literacy on the Choice of Lending Channel by Vietnamese Householders Who Just Escaped Poverty

Purpose: The Newly-Escaped-Poverty-List householders (NEPLH) in Vietnam served as the survey subjects for this study, which sought to determine the impact of "Personal Financial Literacy" on "The Probability of Using Lending Services of Vietnam Bank for Social Policies (P_VBSP)" and "The Probability of Using Informal Private Lending Services (P_ILC)".   Design/methodology/approach: Survey data were collected from 186 respondents, by structured online questionnaire with convenient non-probability sampling technique.  Aspects of personal financial literacy (FLi) such as personal financial knowledge (FL1), personal financial skills (FL2), personal financial attitude (FL3), and personal financial behavior (FL4) are measured. When respondents were divided into groups based on subgroup criteria (CVj), such as gender, age, marital status, role in the family, career, education level, religion, and number of years since being removed from the list of poor households, ANOVA techniques were used to examine differences in various aspects of personal financial literacy. The impact of FLi and subgroup variables (CVj) on P_VBSP and P_ILC was assessed using the binary logistic regression analysis technique.   Findings: Research results show that  there is a statistical difference in the average score of FL1, FL2, FL3 and FL4. The research findings also show that FL2, FL4, and "Career Status – CAR" have a positive impact on P_VBSP, while "Aged group - AGE", "Education level - EDU", and "Number of years since being removed from the list of poor households - YEAR" have a negative impact on P_VBSP. Meanwhile, the P_ILC is positive influenced by the AGE factor and moves in the opposite direction of FL2, FL4, EDU, and YEAR.   Research, Practical & Social implications: The research findings provide the basis for governance implications as well as policy recommendations to promote financial literacy among the NEPLH in Vietnam, encouraging them access policy lending services from the Vietnam Bank for Social Policies, and at the same time help them stay away from informal private lending services, thereby helping them to reduce poverty and achieve sustainable economic development family.   Originality/value: A theoretical framework for personal finance literacy, including (i) financial knowledge, (ii) financial attitude, (iii) financial skills, and (iv) financial behavior, has been developed by the authors after reviewing earlier studies. At the same time, it is more significant to measure financial literacy by objective assessment than relying on the subjective self-assessment of each respondent in the context of actual study in Vietnam. In the model analyzing the influence of personal financial literacy on the decision of Newly-Escaped-Poverty-List householders in choosing the Vietnam Bank for Social Policies or Informal Private Credit Channels, the authors also took into account additional factors including gender, age group, marital status, role in the family, career, education level, religion, and number of years since being removed from the list of poor households

The Potential of Beauveria against Root Mealybugs Formiccoccus sp. (Homoptera: Pseudococidae) Black Pepper in Dak Lak Province of Vietnam

Root mealybugs Formicoccus sp.(Hemiptera: Pseudococcidae) currently emerge as an economically important soil-borne insect pest in the production of black pepper (Piper nigrum L.) in Dak Lak province of Vietnam. Entomopathogenic fungi can be used in agricultural production as feasible safe biocontrol agents and plant growth promoters. This study aimed to isolate, select and identify the local Beauveria sp. strains from the black pepper fields, as well as evaluate the effects of the selected strains on the growth of black pepper. The results showed that the frequency of positive Beauveria sp. soil samples collected from organic black pepper fields was significantly higher than that from conventional black pepper fields. Twenty-one Beauveria sp. strains in black pepper organic fields and four Beauveria sp. strains in black pepper conventional fields were successfully isolated, among them, the Beauveria bassiana BB1 was examined and evaluated for its biocontrol potential against Formicoccus sp. and its ability to promote the growth of black pepper seedlings. In the laboratory experiments, the mortality of both adults and first instar nymph root mealybugs Formicoccus sp. caused by B. bassiana BB1 culminated 100% at 21 days after treatments. In the nethouse, at 6 months after treatment, the efficacy of B. bassiana BB1 against black pepper root mealybugs reached 99.18%. The levels of photosynthetic pigments in the leaves of the black pepper seedlings increased about 2 times compared to the control. Moreover, B. bassiana BB1 strain also remarkably promoted the growth of the black pepper seedlings under the nethouse conditions

Impact of Vocational Education and Training On Decent Job Opportunities Regarding Information and Communication Technology

Vocational education and training plays a crucial part in the creation of decent job. The fast growth of information and communication technology (ICT) during the past ten years has increased work opportunities for laborers. This research uses the yearly labor force survey data to study the impact of vocational education and training on decent job opportunities for employees in the context of Vietnam's information and communication technology development. The logit model results indicate that the 2020 rate of decent jobs is still low, at approximately 25.6 percent. However, vocational education and training and the advancement of ICT positively affect decent job opportunities. This long-lasting impact affects laborers in various areas, regions, and industries. These findings suggest that vocational education and training and ICT must play a significant role in transitioning from precarious to more secure employment, so laborers must acquire professional knowledge and information technology skills

Cloning, expression in Pichia pastoris, and characterization of a thermostable GH5 mannan endo-1,4-β-mannosidase from Aspergillus niger BK01

<p>Abstract</p> <p>Background</p> <p>Mannans are key components of lignocellulose present in the hemicellulosic fraction of plant primary cell walls. Mannan endo-1,4-β-mannosidases (1,4-β-<smcaps>D</smcaps>-mannanases) catalyze the random hydrolysis of β-1,4-mannosidic linkages in the main chain of β-mannans. Biodegradation of β-mannans by the action of thermostable mannan endo-1,4-β-mannosidase offers significant technical advantages in biotechnological industrial applications, <it>i.e</it>. delignification of kraft pulps or the pretreatment of lignocellulosic biomass rich in mannan for the production of second generation biofuels, as well as for applications in oil and gas well stimulation, extraction of vegetable oils and coffee beans, and the production of value-added products such as prebiotic manno-oligosaccharides (MOS).</p> <p>Results</p> <p>A gene encoding mannan endo-1,4-β-mannosidase or 1,4-β-<smcaps>D</smcaps>-mannan mannanohydrolase (E.C. 3.2.1.78), commonly termed β-mannanase, from <it>Aspergillus niger </it>BK01, which belongs to glycosyl hydrolase family 5 (GH5), was cloned and successfully expressed heterologously (up to 243 μg of active recombinant protein per mL) in <it>Pichia pastoris</it>. The enzyme was secreted by <it>P. pastoris </it>and could be collected from the culture supernatant. The purified enzyme appeared glycosylated as a single band on SDS-PAGE with a molecular mass of approximately 53 kDa. The recombinant β-mannanase is highly thermostable with a half-life time of approximately 56 h at 70°C and pH 4.0. The optimal temperature (10-min assay) and pH value for activity are 80°C and pH 4.5, respectively. The enzyme is not only active towards structurally different mannans but also exhibits low activity towards birchwood xylan. Apparent K_mvalues of the enzyme for konjac glucomannan (low viscosity), locust bean gum galactomannan, carob galactomannan (low viscosity), and 1,4-β-<smcaps>D</smcaps>-mannan (from carob) are 0.6 mg mL^-1, 2.0 mg mL^-1, 2.2 mg mL^-1and 1.5 mg mL^-1, respectively, while the k_catvalues for these substrates are 215 s^-1, 330 s^-1, 292 s^-1and 148 s^-1, respectively. Judged from the specificity constants k_cat/K_m, glucomannan is the preferred substrate of the <it>A. niger</it> β -mannanase. Analysis by thin layer chromatography showed that the main product from enzymatic hydrolysis of locust bean gum is mannobiose, with only low amounts of mannotriose and higher manno-oligosaccharides formed.</p> <p>Conclusion</p> <p>This study is the first report on the cloning and expression of a thermostable mannan endo-1,4-β-mannosidase from <it>A. niger </it>in <it>Pichia pastoris</it>. The efficient expression and ease of purification will significantly decrease the production costs of this enzyme. Taking advantage of its acidic pH optimum and high thermostability, this recombinant β-mannanase will be valuable in various biotechnological applications.</p

Impairment of Assets Under Perspectives of International and Vietnamese Accounting

This study investigates the impairment of assets on financial reportings of three separate entities - Vietnam Prosperity Joint-Stock Commercial Bank (VPBank), The Bank of East Asia (BEA) and The Nestlé Group - in the financial year of 2017. By bringing out the differences between international accounting system of asset impairment (IAS 36) and Vietnamese accounting system (VAS), this research has determined the gap between two sets of financial statements under IFRS and VAS in conveying the business performance and financial position. The empirical results show Vietnam’s necessary for a convergence in asset impairment with international accounting system. Therefore, we provide some recommendations for Vietnam in applying asset impairment regarding to IAS 36 partly or completely. Keywords: Asset impairment, International accounting, Vietnamese accounting. DOI: 10.7176/RJFA/10-12-07 Publication date:June 30th 2019

A solution for synchronous incremental maintenance of materialized views based on SQL recursive query

Materialized views are excessively stored query execution results in the database. They can be used to partially or completely answer queries which will be further appeared instead of re-executing query from the scratch. There is a large number of published works that address the maintenance, especially incremental update, of materialized views and query rewriting for using those ones. Some of them support materialized views based on recursive query in datalog language. Although most of datalog queries can be transferred into SQL queries and vise versa but it is not the case for recursive queries. Recursive queries in the data log try to find all possible transitive closures. Recursive queries in SQL (Common Table Expression – CTE) return direct links but not transitive closures. In this paper, we propose efficient methods for incremental update of materialized views based on CTE; and then propose an algorithm for generating source codes in C language for any input SQL recursive queries. The synthesized source codes implement our proposed incremental update algorithms according to inserted/deleted/updated record set in the base tables. This paper focuses mainly on the recursive queries whose execution results are directed tree-structured data. The two cases of tree node are considered. In the first case, a child node has only one parent node and in the second case, a child node can have many parent nodes. Those two cases represent the two types of relationships between entities in real world, that are one–to–many and many–to–many, respectively. For the one–to–many relationships, the relationship data is accompanied with the records describing the child using some fields. Those fields are set as null in deleting a concrete relationship. For the many–to–many relationships, it is stored in a separate table and the concrete relationships are removed by deleting describing records from that table. Considering of enforcing referential integrity may help to reduce the searching space and therefore, help to improve the performance. However, the set of tree nodes or tree edges can be manipulated. All those combinations lead to different algorithms. The experimental results are provided and discussed to confirm the effectiveness of our proposed method