Metric Regularity of the Sum of Multifunctions and Applications

In this work, we use the theory of error bounds to study metric regularity of the sum of two multifunctions, as well as some important properties of variational systems. We use an approach based on the metric regularity of epigraphical multifunctions. Our results subsume some recent results by Durea and Strugariu.Comment: Submitted to JOTA 37 page

Outage performance analysis of non-orthogonal multiple access with time-switching energy harvesting

In recent years, although non-orthogonal multiple access (NOMA) has shown its potentials thanks to its ability to enhance the performance of future wireless communication networks, a number of issues emerge related to the improvement of NOMA systems. In this work, we consider a half-duplex (HD) relaying cooperative NOMA network using decode-and-forward (DF) transmission mode with energy harvesting (Ell) capacity, where we assume the NOMA destination (D) is able to receive two data symbols in two continuous time slots which leads to the higher transmission rate than traditional relaying networks. To analyse EH, we deploy time-switching (TS) architecture to comprehensively study the optimal transmission time and outage performance at D. In particular, we are going to obtain closed-form expressions for outage probability (OP) with optimal TS ratio for both data symbols with both exact and approximate forms. The given simulation results show that the placement of the relay (R) plays an important role in the system performance.Web of Science253918

Variational analysis of paraconvex multifunctions

Our aim in this article is to study the class of so-called ρ- paraconvex multifunctions from a Banach space X into the subsets of another Banach space Y. These multifunctions are defined in relation with a modulus function ρ: X→ [0 , + ∞) satisfying some suitable conditions. This class of multifunctions generalizes the class of γ- paraconvex multifunctions with γ> 1 introduced and studied by Rolewicz, in the eighties and subsequently studied by A. Jourani and some others authors. We establish some regular properties of graphical tangent and normal cones to paraconvex multifunctions between Banach spaces as well as a sum rule for coderivatives for such class of multifunctions. The use of subdifferential properties of the lower semicontinuous envelope function of the distance function associated to a multifunction established in the present paper plays a key role in this study. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Directional metric pseudo subregularity of set-valued mappings: a general model

This paper investigates a new general pseudo subregularity model which unifies some important nonlinear (sub)regularity models studied recently in the literature. Some slope and abstract coderivative characterizations are established. © 2019, Springer Nature B.V

Gamers’ Behavior Via Avatars In Online Games

Gamers use avatars to represent themselves to interact with others in online games. However, gamers’ behavior via avatars has received insufficiently attention by electronic commerce scholars, warranting further study on this issue. Positive interactions among online gamers should foster their loyalty to the game. Therefore, this study investigated how avatar design affects gamers’ behavior via avatars. This study obtained responses from more than one thousand online gamers that were used for further analyses. Criteria were set to exclude some invalid responses, so as to increase data validity. Moreover, reliability and validity were checked by using six tests, demonstrating the adequate performance in psychometric properties. Structural equation modeling was conducted for analyses. This study found that avatar design has an important impact on gamers’ behavior via avatars. Specifically, positive perceptions on avatar design motivate the gamers to exhibit positive behavior via avatars. Findings of this study provide feasible means for electronic commerce managers to encourage gamers’ positive interactions and thus should create strong virtual communities and subsequently loyal gamers

TASK-BASED LANGUAGE TEACHING IN VIETNAM: RESEARCH TRENDS, FINDINGS, AND IMPLICATIONS

It is widely assumed that task-based language teaching (TBLT) has been effectively applied in EFL contexts. In Vietnam, abundant research has been implemented to examine its effects on English proficiency as well as to identify perceptions and attitudes of both teachers and learners towards using this approach in classroom contexts. This paper aims to synthesize trends in research on task-based language teaching in the context by reviewing results extracted from a corpus of 60 studies. Key aspects like effects, challenges, teacher/learner perceptions and attitudes were selected for analysis and synthesis. The results revealed that the research tended to focus more on production skills than receptive skills, and that the implementation of TBLT was reported to cause challenges for teachers, while learners tended to hold positive attitudes toward the approach. Based on the research findings, some lessons were drawn for pedagogy and future research. For successful TBLT implementation, it is suggested that teachers are informed of the effects, engaged in reflections and that exams should be shifted towards communicative competence assessment. Future research could increase sample size and treatment duration, and especially address the challenges teachers, as the main agent, encounter in implementation.  Article visualizations