Experiments and optimization for the WEDM process: A trade-off analysis between surface quality and production rate

This work addressed a parameter optimization to simultaneously decrease the root mean square roughness (Rq) as well as the thickness of the white layer (TW) and improve the material removal rate (MRR) for the wire electro-discharge machining (WEDM) of a stainless steel 304 (SS304). The factors considered are the discharge current (C), the gap voltage (VO), the pulse on time (POT), and the wire drum speed (SP). The interpolative radius basic function (RBF) is applied to show the correlation between the varied factors and WEDM performances measured. The optimal selection is chosen using the multi-objective particle swarm optimization (MOPSO). Moreover, a traditional one using the response surface method (RSM) and desirability approach (DA) is adopted to compare the working efficiency of two optimization techniques. The results showed that the optimal findings of the C, POT, VO, and SP are 5.0 A, 1.0 µs, 61.0 V, and 8.0 m/min, respectively. The values of the Rq and TW are decreased by approximately 33.33% and 23.53%, respectively, while the MRR enhances 47.42% at the optimal selection, as compared to the common values used. The BRF-MOPSO can provide better performance than the RSM-DA

A Target Threat Assessment Method for Application in Air Defense Command and Control Systems

Introduction. This paper presents a solution for threat assessment of air targets using the fuzzy logic inference method. The approach is based on the Sugeno fuzzy model, which has multiple inputs representing target trajectory parameters and a single output representing the target threat value. A set of IF–THEN fuzzy inference rules, utilizing the AND operator, is developed to assess the input information.Aim. To develop and test an algorithm model to calculate the threat value of an air target for use in real-time automated command and control systems.Materials and methods. An algorithm model was developed using a fuzzy model to calculate the threat value of a target. The model is presented in the form of a flowchart supported by a detailed stepwise implementation process. The accuracy of the proposed algorithm was evaluated using the available toolkit in MATLAB. Additionally, a BATE software testbed was developed to assess the applicability of the algorithm model in a real-time automated command and control system.Results. The efficiency of the proposed fuzzy model was evaluated by its simulation and testing using MATLAB tools on a set of 10 target trajectories with different parameters. Additionally, the BATE software was utilized to test the model under various air defense scenarios. The proposed fuzzy model was found to be capable of efficiently computing the threat value of each target with respect to the protected object.Conclusion. The proposed fuzzy model can be applied when developing tactical supporting software modules for real-time air defense command and control systems.Introduction. This paper presents a solution for threat assessment of air targets using the fuzzy logic inference method. The approach is based on the Sugeno fuzzy model, which has multiple inputs representing target trajectory parameters and a single output representing the target threat value. A set of IF–THEN fuzzy inference rules, utilizing the AND operator, is developed to assess the input information.Aim. To develop and test an algorithm model to calculate the threat value of an air target for use in real-time automated command and control systems.Materials and methods. An algorithm model was developed using a fuzzy model to calculate the threat value of a target. The model is presented in the form of a flowchart supported by a detailed stepwise implementation process. The accuracy of the proposed algorithm was evaluated using the available toolkit in MATLAB. Additionally, a BATE software testbed was developed to assess the applicability of the algorithm model in a real-time automated command and control system.Results. The efficiency of the proposed fuzzy model was evaluated by its simulation and testing using MATLAB tools on a set of 10 target trajectories with different parameters. Additionally, the BATE software was utilized to test the model under various air defense scenarios. The proposed fuzzy model was found to be capable of efficiently computing the threat value of each target with respect to the protected object.Conclusion. The proposed fuzzy model can be applied when developing tactical supporting software modules for real-time air defense command and control systems

The distribution of Meiofauna community related to salinity gradient in the Ham Luong estuary, Mekong river

Seventeen taxa of meiofauna community in the Ham Luong estuary were investigated and comprised. Free-living nematodes  were the most dominant and diverse group, presenting about 77% in the total of meiofauna density. Meiofauna density varied from 135.7 ± 33.5 inds/10 cm² to 1782.0 ± 199.5 inds/10 cm². The meiofauna density shows a decreasing trend from inland station to the brackish water station and it is increasing at mouth station. Significant differences in meiofauna density, diversity and Hill’s indices were found between stations. The ANOSIM showed significant differences between stations in meiofauna composition (overall R = 0.972, p = 0.1%). The SIMPER analysis clarifies that the average similarity within stations was quite high, changing from EHL3 (76.2%) to EHL1 (86.1%)

Experiments on the Ionospheric Models in GNSS

In GNSS, one of the main error sources of the Standard Positioning Service (SPS) is introduced by the ionosphere. Although this error can be cancelled by combining two signals at different frequencies, most of the single - frequency mass - market receivers do not benefit from this cancel l ation. For that reason, a set of parameter s is included in the navigation message in order to compute the ionospheric delay of any observation by the Klobuchar model. The Klobuchar model is a very simple model that is able to remove more than the 50% of the ionospheric delay. Recently, more accurate ionospheric models have been introduced such as Global Ionospheric Map (GIM) or the F ast P recise P oint P ositioning ( F PPP ) ionospheric model. In previous works, with data gathered in Europe, it was shown the advantage of the F PPP’s ionospheric model. In this work, we conduct experiments to compare the performance of different ionospheric modelling methods including: Klobuchar, GIM s and F PPP. Our preliminary results show how F PPP and GIM s lead to better positioning precisions compared to the Klobuchar model. However, since data is not wide enough to cover different ionospheric cond itions, more experiments will be carried out in our future work to validate the current result s .Peer ReviewedPostprint (published version

Status Poles and Status Zoning to Model Residential Land Prices: Status-Quality Trade off Theory (Short Paper)

This study describes an approach for augmenting urban residential preference and hedonic house price models by incorporating Status-Quality Trade Off theory (SQTO). SQTO seeks explain the dynamic of urban structure using a multipolar, in which the location and strength of poles is driven by notions of residential status and dwelling quality. This paper presents in outline an approach for identifying status poles and for quantifying their effect on land and residential property prices. The results show how the incorporation of SQTO results in an enhanced understanding of variations in land / property process with increased spatial nuance. A number of future research areas are identified related to the status pole weights and the development of status pole index

Word segmentation of Vietnamese texts: a comparison of approaches

International audienceWe present in this paper a comparison between three segmentation systems for the Vietnamese language. Indeed, the majority of Vietnamese words is built by semantic composition from about 7,000 syllables, that also have a meaning as isolated words. So the identification of word boundaries in a text is not a simple task, and ambiguities often appear. Beyond the presentation of the tested systems, we also propose a standard definition for word segmentation in Vietnamese, and introduce a reference corpus developed for the purpose of evaluating such a task. The results observed confirm that it can be relatively well treated by automatic means, although a solution needs to be found to take into account out-of-vocabulary words

Anticaries activity of mangiferin isolated from Mangifera indica leaves in Vietnam

Mangiferin (1) was isolated from Vietnamese Mangifera indica leaves. Its antimicrobial activities against the oral bacterium Streptococcus mutans GS-5 were evaluated in terms of inhibition of acid production and biofilm formation. The obtained results indicated that mangiferin at the concentration of 0.5 mM clearly inhibited acid production by this organism with a final pH value of 5.2 compared to 3.9 of the control. The reduction in biofilm biomass was found up to 92 % when it was treated with 1.0 mM mangiferin. Thus, mangiferin possesses moderate anticaries activity against S. mutans GS-5. Keywords. Mangifera indica, mangiferin, Streptococcus mutans, anticaries activity

How does the knowledge accumulation process affect Vietnamese entrepreneurs’ success likelihood?

The nationwide economic reform in 1986 transformed Vietnam from a centrally planned economy to a socialist-oriented market economy. Entrepreneurs and entrepreneurial spirits within the populace are suggested to fuel the structural changes. Despite the importance of entrepreneurship in Vietnam’s economy, studies in Vietnam mainly pay attention to the practical aspects of entrepreneurial activities and neglect the cognitive and theoretical aspects of entrepreneurship. Thus, the current study employs the information-processing perspective of the Mindsponge Theory to explore how entrepreneurs’ knowledge accumulation can affect their perceived likelihood of business success. Bayesian analysis indicates that business-related experience positively affects entrepreneurs’ business success likelihood. Greater willingness/readiness to transform thinking, acting, and beliefs can improve the business success of entrepreneurs who study others’ failures carefully. However, for entrepreneurs who perceive learning from others’ failures as unnecessary, higher willingness/readiness to transform diminishes their chance of success. Based on these findings, we recommend Vietnamese entrepreneurs accumulate knowledge through experience, learning, and an open mind for better decision-making and innovation creation capabilities. However, the learning process should be selective

Factors Influence on Promotion Mix in E-marketing: Case of Technology Services Enterprise in Vietnam

Purpose: The objective of this study is to clarify factors affecting the promotion mix in E-Marketing, with specific target audience being enterprises operating in the technology service industry in Vietnam.   Theoretical framework: Based on the promotion theory and social exchange theory, this study focuses on the factors that influence on the promotion decision in firms.   Design/Methodology/Approach: This study applies both qualitative and quantitative methods with data collected from a questionnaire survey.   Findings: There are 4 factors respectively Sales Promotion, Advertising, Public Relations and Personal Selling that affect the mixed promotion activities in E-Marketing of technology service enterprises in Vietnam.   Research, practical & social implications: This study propose solutions to improve the promotion activities in the e – marketing of firms in Vietnam.   Originality/Value: This study is one of the early studies that have focused in this field in Vietnam.Propósito: El objetivo de este estudio es aclarar los factores que afectan la combinación de promoción en E-Marketing, con un público objetivo específico que son las empresas que operan en la industria de servicios de tecnología en Vietnam. Marco teórico: Basado en la teoría de la promoción y la teoría del intercambio social, este estudio se centra en los factores que influyen en la decisión de promoción en las empresas. Diseño/metodología/enfoque: este estudio aplica métodos cualitativos y cuantitativos con datos recopilados de una encuesta de cuestionario. Hallazgos: Existen 4 factores, respectivamente, Promoción de Ventas, Publicidad, Relaciones Públicas y Ventas Personales que afectan las actividades mixtas de promoción en E-Marketing de las empresas de servicios de tecnología en Vietnam. Implicaciones de investigación, prácticas y sociales: este estudio propone soluciones para mejorar las actividades de promoción en el marketing electrónico de las empresas en Vietnam. Originalidad/valor: Este estudio es uno de los primeros que se han centrado en este campo en Vietnam.Objetivo: O objetivo deste estudo é esclarecer os fatores que afetam o mix de promoção no E-Marketing, tendo como público-alvo específico as empresas que operam no setor de serviços de tecnologia no Vietnã.. Referencial teórico: Com base na teoria da promoção e na teoria das trocas sociais, este estudo se concentra nos fatores que influenciam a decisão de promoção nas empresas.. Desenho/metodologia/abordagem: Este estudo aplica métodos qualitativos e quantitativos com dados coletados de uma pesquisa por questionário. Resultados: Existem 4 fatores, respectivamente, Promoção de Vendas, Publicidade, Relações Públicas e Vendas Pessoais que afetam as atividades de promoção mista em E-Marketing de empresas de serviços de tecnologia no Vietnã. Pesquisa, implicações práticas e sociais: Este estudo propõe soluções para melhorar as atividades de promoção no e – marketing de empresas no Vietnã. Originalidade/valor: Este estudo é um dos primeiros estudos que se concentraram neste campo no Vietnã. Palavras-chave:  Mix de promoção; E-Marketing; Serviços de tecnologia; Vietn

Practice skills and compliance of private pharmacies with regulations on the prescription drug: A multi-method study in Vietnam

Professional practice of pharmacists plays a crucial role in the reinforcement of drug retailers’ services to achieve optimal health care provision to customers. To evaluate the professional skills and compliance of retail pharmacy staff with selling prescription drugs by surveying patients’ knowledge of drugs and role-playing the customer buying antibiotics without a prescription. A cross-sectional study was conducted with two kinds of surveys at 480 drug retail establishments using the cluster sample technique among 12 provinces/cities in Vietnam. Clients were interviewed to assess their knowledge about drugs. Moreover, the method of acting as a client was used in two common scenarios in order to evaluate the implementation of professional regulations and professional practice skills of drug sellers: a child acute respiratory infection (ARI) case and an amoxicillin case without a prescription. The data were presented as frequency and percentage. The basic tests were used to compare the ratios and means between the two groups. The total number of interviewed customers was 2389 while the figure for role-playing was 960 cases. When customers buy medications with a prescription, 100% of those were fully aware of the dosage of the drugs they purchased, which was higher than the scenario of buying without a prescription (93.1%). In role-play scenarios, the rate of drug sellers asking patients to explore information was higher in the ARI children case than in the amoxicillin case. Besides, 100% of customers were consulted on treatment in both cases, and the rate of advising was at a low rate in both scenarios 3.8% in the amoxicillin case compared to 15.4% in the ARI case. Drug sellers did not respond well to requirements in professional practice and were influenced by economic concerns in business