On the energy efficiency of NOMA for wireless backhaul in multi-tier heterogeneous CRAN

This paper addresses the problem of wireless backhaul in a multi-tier heterogeneous cellular network coordinated by a cloud-based central station (CCS), namely heterogeneous cloud radio access network (HCRAN). A non-orthogonal multiple access (NOMA) is adopted in the power domain for improved spectral efficiency and network throughput of the wireless downlink in the HCRAN. We first develop a power allocation for multiple cells of different tiers taking account of the practical power consumption of different cell types and wireless backhaul. By analysing the energy efficiency (EE) of the NOMA for the practical HCRAN downlink, we show that the power available at the cloud, the propagation environment and cell types have significant impacts on the EE performance. In particular, in a large network, the cells located at the cloud edge are shown to suffer from a very poor performance with a considerably degraded EE, which accordingly motivates us to propose an iteration algorithm for determining the maximal number of cells that can be supported in the HCRAN. The results reveal that a double number of cells can be covered in the urban environment compared to those in the shadowed urban environment and more than 1.5 times of the number of microcells can be deployed over the macrocells, while only a half number of cells can be supported when the distance between them increases threefol

INTEGRATING EXTENSIVE READING INTO THE LESSONS: ITS EFFECTS ON EFL HIGH SCHOOL STUDENTS’ READING PERFORMANCE

This one-group experimental study attempts to investigate the effects of integrating extensive reading, especially the integration of the two main reading skills namely skimming and scanning skills into the reading lessons on EFL high school students’ reading performance. The participants were 62 grade-10 students studying in a high school in the Mekong Delta, Vietnam. The four main instruments used to collect the data included Reading Tests (consisting of Pre-test and Post-test), a questionnaire, a semi-structured interview, and a pre-program survey, respectively. The results of the data analysis indicated a relatively significant impact of extensive reading on students’ reading performance, especially the improvement of two reading skills, namely skimming and scanning. In addition, it confirmed that the participants had a positive attitude towards the integration of extensive reading into the reading lessons. The present study showed the main implication that the incorporation of extensive reading into the reading lessons should get more attention in language teaching programs at secondary education. Article visualizations

TEACHERS AS RESEARCHERS: THE PERCEPTIONS AND PRACTICES OF CANTHO TERTIARY EFL TEACHERS

This descriptive study aims to investigate tertiary EFL teachers’ perceptions and practices of doing research. The study was conducted with the participation of 67 EFL teachers from tertiary institutions in Cantho of Vietnam. Quantitative and qualitative data were gathered via the questionnaire and semi-structured interviews to provide insights into how Cantho tertiary EFL teachers perceive the benefits and challenges of doing research as well as their current status of practices as researchers. The study revealed that (1) Cantho tertiary teachers held positive perceptions of conducting research in the field of English language teaching, and that (2) their practices as researchers were reported to be at a high level. Understanding these is an important part of the broader process of attempting to resolve research challenges teachers are facing and thus to encourage teacher research engagement among EFL teachers. Article visualizations

STUDENT EVALUATION OF TEACHING EFFECTIVENESS: AN INVESTIGATION INTO TEACHERS’ AND STUDENTS’ PERCEPTIONS

This descriptive study aims to investigate how EFL teachers and EFL students perceive Student Evaluation of Teaching Effectiveness (SETE) as well as to seek for possible similarities and differences between the two groups’ perceptions. The current study was conducted with the participation of 60 teachers and 100 students at an EFL Language Center in the Mekong Delta, Vietnam. Quantitative and qualitative data were collected via questionnaires and semi-structured interviews. Main findings reveal that: (1) almost all teachers and students are highly aware of SETE in relation to its necessity and benefits except for its validity and reliability; (2) the two groups of participants acknowledged their frequent participation in SETE and expressed their preferences for certain SETE procedures; (3) there are major similarities and differences between teachers’ and students’ perceptions of SETE.  Article visualizations

THE EFFECTS OF THINK-ALOUD STRATEGY ON EFL YOUNG LEARNERS’ READING SKILL PRACTICE

Think-aloud is described as a strategy in which students verbalize their thoughts while they read. This strategy is used to help students monitor their own thinking and comprehend the text. This current study aimed to examine the effects of the think-aloud strategy on EFL young learners’ reading skill practice and identify their attitudes towards the think-aloud strategy used by the teacher in teaching at a foreign language center in Can Tho city (Southern Vietnam’s Mekong Delta region). This study was experimental research using both quantitative and qualitative approaches. The quantitative approach was used to investigate the effects of the think-aloud strategy on young learners’ reading skill practice while the qualitative data was collected to understand the young learners’ attitudes towards the use of the think-aloud strategy in teaching and learning reading skills. Pre-test, post-test, and semi-structured interviews were used to collect the data. The study was conducted with one group of participants. The participants included 25 students who were at the age of 10-12 years old. The results from the pre-test and post-test showed that there was a significant difference in the students‘ reading comprehension performance after the intervention. Thus, the think-aloud strategy has a great impact on the improvement of students’ reading comprehension. Besides, there was no difference in reading comprehension achievement between males and females before and after the treatment. Especially, the results from the semi-structured interview revealed that all students had positive attitudes towards the think-aloud strategy.  Article visualizations

AN INVESTIGATION INTO EFL UNDERGRADUATE STUDENTS’ RESEARCH COMPETENCE DEVELOPMENT AT UNIVERSITY OF FOREIGN LANGUAGES AND INTERNATIONAL STUDIES, HUE UNIVERSITY, VIETNAM

This study aimed at exploring EFL students’ attitudes towards doing research at the undergraduate level, the perceived practice of research competence and the factors facilitating the development of research competence. The population of the study was EFL undergraduate students studying at University of Foreign Languages and International Studies, Hue University. The sample of the study comprised 120 second-year, third-year and fourth-year students majoring in English Language Teaching and English Language Studies. The data was collected through questionnaires and semi-structured interviews. The results show that EFL students thought that doing research is important to their future career path, but they were not confident to do their own research. In terms of EFL students’ perceived practice of research competence, thinking of a research topic and writing theoretical background posed challenges for EFL students, while using PowerPoint to present their research was the activity, they felt most confident to do. The participants did not show entire support for the role of the library and the faculty in facilitating the research competence development at a high level. These findings imply that the library and the faculty should provide more various databases for students as well as opportunities to be familiar with doing research.  Article visualizations

Extended Model for Integrating Culture into Teaching EFL: A Context of Vietnam

Intercultural competence (IC) has gained a better positionality in English as a Foreign Language (EFL) education in Vietnam to enable young people to become effective global citizens. Accordingly, the development of comprehensive IC is considered to be an officially stated objective of the reformed EFL curriculum, and a great body of intercultural issues reflecting the cultural diversity of countries has been added to the English course books of the upper secondary level. To help EFL teachers with the exploitation of the coursebooks, this perspective paper aims to propose a model for Intercultural Language Learning and Teaching (IcLLT) to shed light on how to integrate culture into teaching EFL in a Vietnamese pedagogical teaching context. This model can be a valuable guideline for EFL teachers to go beyond the language skill-based lesson in order to promote learners’ intercultural communicative competence

On the energy efficiency of NOMA for wireless backhaul in multi-tier heterogeneous CRAN

This paper addresses the problem of wireless backhaul in a multi-tier heterogeneous cellular network coordinated by a cloud-based central station (CCS), namely heterogeneous cloud radio access network (HCRAN). A non-orthogonal multiple access (NOMA) is adopted in the power domain for improved spectral efficiency and network throughput of the wireless downlink in the HCRAN. We first develop a power allocation for multiple cells of different tiers taking account of the practical power consumption of different cell types and wireless backhaul. By analysing the energy efficiency (EE) of the NOMA for the practical HCRAN downlink, we show that the power available at the cloud, the propagation environment and cell types have significant impacts on the EE performance. In particular, in a large network, the cells located at the cloud edge are shown to suffer from a very poor performance with a considerably degraded EE, which accordingly motivates us to propose an iteration algorithm for determining the maximal number of cells that can be supported in the HCRAN. The results reveal that a double number of cells can be covered in the urban environment compared to those in the shadowed urban environment and more than 1.5 times of the number of microcells can be deployed over the macrocells, while only a half number of cells can be supported when the distance between them increases threefol

Evaluating of chlorpyrifos-degrading by bacterial strains in mineral salt minimum and in the soil

Four bacterial strains degraded chlorpyrifos, isolated from agricultural soil, were used as a source of bacteria to investigate their ability to decompose chlorpyrifos in mineral salt minimum and the soil. Barrientosimonas humi C4.3 was investigated for the decomposition of chlorpyrifos in this strain on different days (10, 20 and 30 days of culture) as supplemented and not supplemented TSB. At the same time, another experiment was carried out to evaluate the chlorpyrifos etherification of B. humi C4.3 and the four strains of Achromobacter xylosoxidans C3.1, B. humi C4.3, Microbacterium sp. C8.9, Staphylococcus pasteuri C9.2 in a soil environment. The experiment was carried out including 3 treatments, each treatment was repeated 3, two soil types (sterile soil and non-sterile soil) and bacteria (single bacteria and four bacterial species). The results showed that, in the same culture period of 30 days incubation, biodegradable chlorpyrifos of B. humi C4.3 in the mineral salt medium was more effective (63.07% biodegradable chlorpyrifos) than when grown in soil (21.4% biodegradable chlorpyrifos). Also, biodegradable chlorpyrifos of B. humi C4.3 that was cultured in sterile soil was higher than in non-sterile soil

A case of hepatic cyst-induced internal jugular venous thrombosis

• Echocardiography can demonstrate hepatic cyst–induced right atrial compression. • Hepatic cyst–induced blood flow stasis can cause internal jugular venous thrombus. • Laparoscopic deroofing of hepatic cysts is a safe and effective treatment