An approximate method for analysing non-linear systems subject to random excitation

A solution technique based on the representation of the response of the non-linear system by a polynomial of the response of the linearized system is presented. The relation between the original non-linear system and the linearized system is introduced by considering the so-called extended moment equations and their closed set is to be solved to determine unknowns. For the Vanderpol oscillator subject to white noise excitation, the technique gives good approximation to the response moments as well as the probability density function

Factors Influencing Customers’ Perception of Digital Banking Service Quality in Vietnam

Purpose: This paper examines the impacts of gender, education, and age on consumer’s perception of digital banking service quality in the case of a branch of Bank for Investment and Development of Vietnam.   Theoretical framework: Inspired by Parasuraman‘s five dimensions of service quality, this research defined four criteria measured digital banking service quality including the security, the ability, the convenience, and the supported policies for customers. Among different factors influencing consumers’ perception, the authors selected to analyzed impacts of education, gender, and age of consumers.   Design/Methodology/Approach: Primary data was collected from 200 customers who were randomly selected, then analyzed by descriptive statistics. The T-test, Cronbach Alpha, and ANOVA were used to test the differences of consumers’ perception of digital banking service quality by their gender, age, and education.   Findings: The analysis showed that consumers’ perception of digital banking service quality clearly differed by their gender and age. Nevertheless, there was not a clear correlation between educational levels and their perception of security, convenience, and promotion policies of digital banking services.   Research, Practical & Social implications: The findings imply that Vietnamese commercial banks need to improve the quality of digital banking services by: cooperating with Fintech companies to increase security, improving human resource quality, innovating technology and promoting communication activities.   Originality/Value: This study indicated the differences of consumers’ perception of digital banking service quality by their age, gender, and education. All the respondents of the survey are digital banking service users.

Empirical Investigation of Omni-channel Customer Behavior: Multiple Mediation Effects of Website and Mobile Interactivity

While existing retail research has focused on retail channels in isolation from a single or multi-channel retailing perspective, there is a need to investigate shopping behavioral intention from an omni-channel and customer-centric retailing perspective. The main of this study is to analyze the customer omni-channel behavior under multiple mediating effects of website and mobile interactivity. Data collected from valid 287 respondents via both online and paper form. Partial least squares structural equation modeling (PLS-SEM) and Smart-PLS software have been used to test proposed hypotheses. The result underlined the significant positive effects of technology literacy, attitude towards website interactivity and attitude towards mobile device interactivity on customer’s behavioral intention. Moreover, website interactivity and augmented reality have highest impact attitude towards website interactivity and attitude towards mobile device interactivity respectively

Comment valoriser le travail dans la production agricole : une étude de cas dans le delta du fleuve Rouge, au Vietnam

In Vietnam rural area, agricultural production is still a main occupational activity of millions laborers and be major income source of them. Despite this important role, it is often debated that the most concerning issue in labor market of Vietnam rural areas is job creation. In other word, the actual capacity of agriculture to create new employment is rather low compare to non-agricultural sectors. This issue leads to the large migration of young, experienced and skilled laborers from rural to urban areas as well as from agriculture to non-agricultural sectors. As a consequence, agricultural labor in many provinces of the country are mostly un-trained and the old aged. This shortage of skilled laborers not only directly affects agricultural production at farm household level but also is a challenge to the implementation of rural renewal targets of the Vietnamese Government. Furthermore, the lack of new job creation for agricultural works in parallel with poor skilled and old aged result in the low wage rate of laborers who work in agricultural sector. This wage rate is equivalent to two-third of the wage of employees in industrial sector, and 50% of the wage of those working in service sector. Not only wage, other forms of value of agricultural employees such as social protection, working condition are also less concerned by employers in rural labor market and the current Vietnam Labor Code neither. In order cope with the shortage of skilled farm labor, rural households in the Red River delta diversify their use of labor by combining family laborers with hired laborers for agricultural activities. Family labor source contains both family farm laborers and family non-farm laborers but still participating in farming activities of the household, especially in the peak season. Within 220 households of the three provinces investigated in this thesis, the highest proportion of family farm laborers is over 45 years old and women are discovered to mostly in charge in agricultural production, especially in rice farming. That is because more non-farm jobs opportunities open for young, healthy, and skilled men rather than women. Hired laborers in agriculture in Bac Ninh, Hai Duong and Thai Binh provinces are divided into two types, seasonal hired laborers and permanent hired laborers. Seasonal laborers are often hired to work in peaking time. In rice farming households, seasonal hired laborers usually work for short period of time such as for the land preparing, transplanting, and harvesting. In clam farming households, seasonal laborers are widely rent in preparing clam plots and harvesting. In general, women are observed to work in seasonal hiring more frequently than men in both household groups. However, seasonal hired laborers are not detected in pig farming group. Alternatively, laborers in this group are hired on a permanent or longer-term basis, normally from three months to a year. When using hired laborers in agricultural production, farm households give the laborers payment that are equivalent to their labor value. Of these payment, wage is considered as the most important value of hired laborers. Basically, the wage is paid in two methods, daily wage for seasonal laborers and monthly wage for permanent ones. The daily wage is applied for farming activities which last within a few days such as manual transplanting, manual harvesting in rice farming or clam harvesting. The daily wage may be paid in piece for activities such as land preparation and spraying pesticide. Whereas, the monthly wage is common for laborers in pig farming and clam plot guarding. The wage is counted for 30 working days. Average monthly wage of a hired laborer is 161 USD in pig farming and 175 USD in clam farming. Thus, wage rate of hired farm labor in the study sites is equivalent to 70% and 66% of the wage of laborers in industrial and service sector, respectively. A part from the wage, there are different forms of labor values paid by the householders through remuneration such as drink, lunch, bonus for good performance and support for sickness. Such remuneration can be paid in cash or in kind which ranges from 0.3 to 9 USD. For hired laborers, labor welfare usually is a luxury metric as they work in farm households with only verbal agreement. Without written contract, they receive no health insurance and social insurance support. Despite the rather low in wage and labor welfare, hired laborers still present the satisfaction with their employment. Wage is a work feature which contributes the most to their satisfaction, relation with householder is the second important factor. This relationship proves a crucial function of social relation in driving labor supply and demand in agricultural labor market rather than an economic one. Similar to many developing countries, imperfect information is a typical characteristic of the agricultural labor market of the Red River delta, Vietnam. This imperfection influences labor demand in terms of raising cost for monitoring hired laborers of farm households. On the other side, labor migration is considered as a determinant impacting on labor supply of the rural labor market. This study discovers a positive correlation between remittance of migrated laborers sending home and wage paid to hired laborers in the pig and clam farming groups. Conversely, the more development of agricultural machinery renting market, the less value that householders have to pay for hiring manual farm laborers. In addition to these external determinants, farm size of household, gender and work experience are internal factors which impact on the wage rate that hired laborers can receive. Among the three household groups, the wage of hired laborers in the clam farming is 3.9% higher than the one in the rice farming group. In order to increase the labor value in agricultural production, several interventions by central government and local authorities at different levels in the Red River delta should be taken into account: (1) including agricultural wage laborers into the governance of labor code; (2) promoting the operation of employment service centers in rural areas; (3) improving work skill of farm laborers above 40 years old through training courses which connect with labor demand in the rural labor market.Dans la zone rurale du Vietnam, la production agricole reste une activité professionnelle principale de millions de travailleurs et en est la principale source de revenus. Malgré ce rôle important, il est souvent débattu que la question la plus préoccupante sur le marché du travail des zones rurales du Vietnam est la création d'emplois. En d'autres termes, la capacité réelle de l'agriculture à créer de nouveaux emplois est plutôt faible par rapport aux secteurs non agricoles. Cette question entraîne une forte migration de jeunes travailleurs expérimentés et qualifiés des zones rurales vers les zones urbaines ainsi que de l'agriculture vers les secteurs non agricoles. En conséquence, la main-d'œuvre agricole dans de nombreuses provinces du pays est pour la plupart des personnes non formées et âgées. Cette pénurie/le manque de travailleurs qualifiés affecte non seulement directement la production agricole au niveau des ménages agricoles, mais constitue également un défi pour la mise en œuvre des objectifs de l'innovation rurale du gouvernement vietnamien. En outre, le manque de création de nouveaux emplois pour les travaux agricoles en parallèle avec les personnes peu qualifiées et les personnes âgées se traduit par le faible taux de salaire des travailleurs qui travaillent dans le secteur agricole. Ce taux de salaire est équivalent aux deux tiers du salaire des salariés du secteur industriel et à 50% du salaire de ceux qui travaillent dans le secteur des services. Non seulement le salaire, ni les autres formes de valeur des employés agricoles tels que la protection sociale, les conditions de travail sont également moins concernés par les employeurs du marché du travail rural et le Code du travail Vietnamien actuel. Afin de faire face à la pénurie de main-d'œuvre agricole qualifiée, les ménages ruraux du delta du fleuve Rouge diversifient leur utilisation de la main-d'œuvre en combinant les travailleurs familiaux non rémunérés avec des travailleurs embauchés pour les activités agricoles. La source de main-d'œuvre familiale comprend à la fois des travailleurs des familles agricoles et des travailleurs des familles non agricoles, mais participant toujours aux activités agricoles du ménage, en particulier pendant la haute saison. Au sein de 220 ménages des trois provinces étudiées dans cette thèse, la proportion la plus élevée de travailleurs des familles agricoles a plus de 45 ans et les femmes se retrouvent principalement responsables de la production agricole, en particulier de la riziculture. C'est parce que plus d'opportunités d’emplois non agricoles s'ouvrent aux hommes jeunes, en bonne santé et qualifiés plutôt qu'aux femmes. Les travailleurs embauchés dans l'agriculture dans les provinces de Bac Ninh, de Hai Duong et de Thai Binh sont divisés en deux types, les travailleurs saisonniers et les travailleurs permanents. Les travailleurs saisonniers sont souvent embauchés pour travailler en période de pointe. Dans les ménages de la riziculture, les travailleurs saisonniers embauchés travaillent généralement pendant une courte période, par exemple pour la préparation des sols, la transplantation et la récolte. Dans les ménages d'éleveurs de palourdes, les travailleurs saisonniers sont largement loués pour la préparation des parcelles de palourdes et la récolte. En général, on observe que les femmes travaillent en embauche saisonnière plus fréquemment que les hommes dans les deux groupes de ménages. Cependant, les travailleurs saisonniers embauchés ne sont pas observés dans le groupe d'élevage de porcs. Alternativement, les travailleurs dans ce groupe sont embauchés sur une base permanente ou à plus long terme, normalement de trois mois à un an. Lorsqu'ils utilisent des travailleurs embauchés dans la production agricole, les ménages des familles agricoles versent aux travailleurs une rémunération équivalente à leur valeur de travail. De ces paiements, le salaire est considéré comme la valeur la plus importante des travailleurs embauchés. Fondamentalement, le salaire est payé selon deux méthodes, le salaire journalier pour les travailleurs saisonniers et le salaire mensuel pour les travailleurs permanents. Le salaire journalier est appliqué pour les activités agricoles qui durent quelques jours comme le transplantation manuelle, la récolte manuelle en riziculture ou la récolte de palourdes. Le salaire journalier peut être payé en proportion de l'ouvrage effectué pour des activités telles que la préparation des sols et la pulvérisation de pesticides. Tandis que, le salaire mensuel est commun pour les travailleurs dans l'élevage porcin et la garde des parcelles de palourdes. Le salaire est calculé pendant 30 jours ouvrables. Le salaire mensuel moyen d'un ouvrier embauché est de 161 USD dans l'élevage porcin et de 175 USD dans l'élevage de palourdes. En moyenne, le taux de salaire de la main-d'œuvre agricole embauchée dans les sites d'étude équivaut à 70% et 66% du salaire des ouvriers du secteur industriel et des services, respectivement. Hormis le salaire, il existe différentes formes de valeur du travail payées par les ménages par le biais de rémunérations telles que la boisson, le déjeuner, la prime aux bonnes performances et le soutien en cas de maladie. Cette rémunération peut être versée en espèces ou en nature dans la gamme de 0,3 à 9 USD. Pour les travailleurs embauchés, le bien-être du travail est souvent un droit luxueux, car ils travaillent dans des ménages agricoles avec accord verbal seulement. Sans contrat écrit, ils ne reçoivent ni assurance maladie ni soutien aux assurances sociales. Malgré le salaire et le bien-être du travail plutôt bas, les travailleurs embauchés présentent toujours la satisfaction de leur emploi. Le salaire est une caractéristique du travail qui contribue le plus à leur satisfaction, la relation avec le chef de ménage est le deuxième facteur important. Cette relation s'avère une fonction cruciale de la relation sociale pour stimuler l'offre et la demande de main-d'œuvre sur le marché du travail agricole plutôt que sur l’économie. Similaire à de nombreux pays en développement, les informations imparfaites sont une caractéristique typique du marché du travail agricole du delta du fleuve Rouge, au Vietnam. Cette imperfection influe sur la demande de main-d'œuvre en termes d'augmentation des coûts de surveillance des travailleurs salariés des ménages agricoles. D'un autre côté, la migration de main-d'œuvre est considérée comme un facteur déterminant de l'offre de main-d'œuvre du marché du travail rural. Cette thèse découvre une corrélation positive entre les transferts d'argent des travailleurs migrants renvoyés chez eux et le salaire payé aux travailleurs embauchés dans les groupes d'élevage de porcs et de palourdes. Inversement, plus le marché de la location de machines agricoles est développé, moins les ménages doivent payer pour embaucher des ouvriers agricoles. En plus de ces déterminants externes, la taille de la ferme du ménage, le sexe et l'expérience professionnelle sont des facteurs internes qui influent sur le taux de salaire que les travailleurs embauchés peuvent recevoir. Parmi les trois groupes de ménages, le salaire des travailleurs embauchés dans l'élevage de palourdes est supérieur de 3.9% à celui du groupe de la riziculture. Afin d'augmenter la valeur du travail dans la production agricole, plusieurs interventions du gouvernement central et des autorités locales à différents niveaux dans le delta du fleuve Rouge devraient être prises en compte: (1) inclure les travailleurs du salaire agricole dans la gouvernance du code du travail; (2) promouvoir le fonctionnement des centres de services d'emploi dans les zones rurales; (3) améliorer des compétences professionnelles des travailleurs agricoles de plus de 40 ans grâce à des cours de formation liés à la demande de main-d'œuvre sur le marché du travail rural

Extension of method of moment equation to nonlinear deterministic vibrations

The paper present the so-called "an extended averaged equation approach" to the investigation of nonlinear vibration problems. The numerical results in analysing the vibration systems with weak, middle and strong non-linearity show the advantages of the method

Unveiling the dynamics of motivation, work-life balance, and work engagement among Vietnamese employees in multinational corporations

This paper investigates the factors influencing work engagement among local Vietnamese staff in multinational corporations by focusing on the impacts of work motivation and work-life balance on work engagement. It explores the role of salary, bonuses, financial rewards, and career promotion in shaping employees’ motivation. A structured questionnaire was administered to 279 respondents working at Samsung Electronics Vietnam Co., Ltd. The collected data were analyzed using the partial least squares structural equation modeling (PLS-SEM) techniques and SmartPLS software. The findings reveal that career promotion opportunities significantly influence work motivation, surpassing salary, bonuses, and financial rewards. Work motivation and work-life balance positively affect work engagement, with work motivation exhibiting a more substantial impact. The study emphasizes the importance of clear career paths and growth opportunities in enhancing employee work motivation and engagement. It also underscores the need for organizations to create a supportive work environment, offer competitive compensation packages, and implement recognition programs. These findings have practical implications for multinational corporations operating in Vietnam, highlighting the significance of prioritizing employee career progression, promoting work-life balance, and fostering a motivating work environment

Extended averaged equation method and application on analyzing some nonlinear deterministic vibrations

The paper presents an extended averaged equation approach to the investigation of nonlinear vibration problems. The proposed method is applied to some free/self excited oscillator, nonlinear free and forced oscillations of a suspension system with two-degree-of-freedom. The results in analyzing the vibration systems with different nonlinearity show the efficiency and advantages of the method

Green Tribology

This chapter provides an overview of Green tribology, which is a new direction in the development of tribology, a new interesting area for scientific researches and a new way to turn tribology into a friend of ecological environment and saving energy. Green tribology is considered as well as close area with other “green” disciplines like green engineering and green chemistry. In the chapter, the various aspects of green tribology such as the concept, perspectives, role and goal, main principles, primary areas, challenges and directions of the future development have been discussed. It was clarified that green tribology can be defined as an interdisciplinary field attributed to the broad induction of various concepts such as energy, materials science, green lubrication, and environmental science. The most important role and goal of green tribology is improvement of efficiency by minimizing wear and friction in tribological processes to save energy, resources and protect environment, and consequently, improve the quality of human life. The twelve principles and three areas of green tribology were analyzed. Observation of these principles can greatly reduce the environmental impact of tribological processes, assist economic development and, as a result, improve the quality of life. The integration of these areas remains the major challenge of green tribology and defines the future directions of research in this field. This work also presents a rather detailed analysis of the most important effect in green tribology—the “zero-wear” effect (selective transfer effect). It was established that the “zero-wear” effect is due to self-organization in frictional interaction in tribological systems, which is the consequence of the complex tribo-chemical reactions and physico-chemical processes occurred in the area of frictional contact, that lead to the manifestation of unique tribological characteristics: super-antifrictional (friction coefficient ~ 10−3) and without wear (intensity wear ~10−15). This condition of tribo-system was provided by a protective nanocrystalline servovite film made of soft metal with unusual combination of mechanical properties

MODAL ANALYSIS OF MULTISTEP TIMOSHENKO BEAM WITH A NUMBER OF CRACKS

Modal analysis of cracked multistep Timoshenko beam is accomplished by the Transfer Matrix Method (TMM) based on a closed-form solution for Timoshenko uniform beam element. Using the solution allows significantly simplifying application of the conventional TMM for multistep beam with multiple cracks. Such simplified transfer matrix method is employed for investigating effect of beam slenderness and stepped change in cross section on sensitivity of natural frequencies to cracks. It is demonstrated that the transfer matrix method based on the Timoshenko beam theory is usefully applicable for beam of arbitrary slenderness while the Euler-Bernoulli beam theory is appropriate only for slender one. Moreover, stepwise change in cross-section leads to a jump in natural frequency variation due to crack at the steps. Both the theoretical development and numerical computation accomplished for the cracked multistep beam have been validated by an experimental stud