EFL TERTIARY STUDENTS' PERCEPTION AND PRACTICE WITH LANGUAGE LEARNING BEYOND THE CLASSROOM: THE CASE OF VIETNAM

While language teaching is widely acknowledged as preparation for real-life language use, attention is still focused mainly on classroom-bounded learning. However, the development of technology allows language learners to extend their learning opportunities beyond the classroom. Using a mixed method design that included questionnaires and semi-structured interviews, this study aims to explore how Vietnamese EFL tertiary students perceive and utilize language learning beyond the classroom (LLBC) resources in learning English. This study finds that the students perceived well the feasibility of the LLBC, and believed in the benefits of LLBC resources and activities in improving pronunciation and vocabulary, listening, and speaking skills. In addition, the students are found also to try to develop strategies for making the most of individual LLBC resources and activities to improve their English proficiency. The study also provides implications for the teachers to prepare and equip themselves with the effective utilization of LLBC resources and activities to provide their students with helpful advice.  Article visualizations

VIETNAMESE EFL TEACHERS’ USE OF THE SET OF NEW ENGLISH TEXTBOOKS TIENG ANH 11 AS RESOURCES FOR ACHIEVEMENT TESTS

The paper reported on part of a study investigating Vietnamese upper secondary school EFL teachers’ use of the set of new English textbooks Tieng Anh 11 as resources for achievement tests. To carry out this research, both qualitative and quantitative approaches including questionnaires and interviews were used to collect the data from research participants at some upper secondary schools in Quang Tri Province, Vietnam. The findings of the study showed the teachers’ practices in using the set of new English textbooks Tieng Anh 11 for achievement tests. They reported adapting the exercises and activities, following the teaching procedures, and referring to the book maps in the set of new English textbooks Tieng Anh 11 to organize revision, design one-period tests and semester exams. Especially, using the accompanying workbooks to revise what students learned accounted for the highest rate. Besides, major challenges of the upper-secondary school teachers in using this set are also uncovered through the results. The teachers mostly have difficulties in finding the relevant materials matching the prescribed test formats as well as the required language competence in the set of new English textbooks Tieng Anh 11, lacking the test formats and scoring criteria associated with achievement tests. From the research findings, some implications were suggested for teachers’ flexibility in teaching and test preparation processes, and for improving the set of new English textbooks Tieng Anh 11. Article visualizations

Symmetry-preserving graph attention network to solve routing problems at multiple resolutions

Travelling Salesperson Problems (TSPs) and Vehicle Routing Problems (VRPs) have achieved reasonable improvement in accuracy and computation time with the adaptation of Machine Learning (ML) methods. However, none of the previous works completely respects the symmetries arising from TSPs and VRPs including rotation, translation, permutation, and scaling. In this work, we introduce the first-ever completely equivariant model and training to solve combinatorial problems. Furthermore, it is essential to capture the multiscale structure (i.e. from local to global information) of the input graph, especially for the cases of large and long-range graphs, while previous methods are limited to extracting only local information that can lead to a local or sub-optimal solution. To tackle the above limitation, we propose a Multiresolution scheme in combination with Equivariant Graph Attention network (mEGAT) architecture, which can learn the optimal route based on low-level and high-level graph resolutions in an efficient way. In particular, our approach constructs a hierarchy of coarse-graining graphs from the input graph, in which we try to solve the routing problems on simple low-level graphs first, then utilize that knowledge for the more complex high-level graphs. Experimentally, we have shown that our model outperforms existing baselines and proved that symmetry preservation and multiresolution are important recipes for solving combinatorial problems in a data-driven manner. Our source code is publicly available at https://github.com/HySonLab/Multires-NP-har

Improvement of Step Tracking Algorithm Used for Mobile Receiver System via Satellite

In the mobile communication via satellite, received systems are mounted on the mobile device such as ship, train, car or airplane. In order to receive continuous signals, received antenna system must be steered in both the azimuthal and elevation angle to track a satellite. This paper proposes the improved step-tracking algorithm using for mobile receiver system via satellite Vinasat I. This paper also presents the results of study, design and manufacture of the discrete-time controller system for the fast tracking of a satellite by applying an improved step tracking algorithm with fuzzy proportional integral derivative proportional integral derivative controller. Simulated and experimental results indicate that the system performances obtain from applying the improved step tracking algorithm and the fuzzy controller was better than traditional control systems

AN INVESTIGATION INTO QUANG TRI PRIMARY SCHOOL ENGLISH LANGUAGE TEACHER’S PERSPECTIVE OF ICT INTEGRATION DURING THE COVID-19 PANDEMIC

With the transition from face-to-face classes to online classes during Covid-19 epidemic, teachers in Quang Tri have no choice but to integrate ICT into their teaching. At this time ICT has become the most essential tool in educational settings and the subject of many researchers. This study aims to investigate how English teachers perceived ICT integration in terms of the benefits, difficulties as well as challenges of incorporating ICT. The study adopted both quantitative and qualitative methods of data collection, i.e., questionnaires and interviews. The findings revealed that the majority of English teachers had a positive perception of integrating ICT due to its effectiveness. However, it was also reported that lack of technical support from schools, and limited knowledge and training in ICT discouraged teachers from using ICT. The study offers useful implications for teachers to integrate ICT in teaching English during the pandemic time.  Article visualizations

Mapping the Linearly Polarized Spectral Line Emission around the Evolved Star IRC+10216

We present spectro-polarimetric observations of several molecular lines obtained with the Submillimeter Array (SMA) toward the carbon rich AGB star IRC+10216. We have detected and mapped the linear polarization of the CO 3-2, SiS 19-18 and CS 7-6 lines. The polarization arises at a distance of ~450 AU from the star and is blueshifted with respect the Stokes I. The SiS 19-18 polarization pattern appears to be consistent with a locally radial magnetic field configuration. However, the CO 3-2 and CS 7-6 line polarization suggests an overall complex magnetic field morphology within the envelope. This work demonstrates the feasibility of using spectro-polarimetric observations to carry out tomographic imaging of the magnetic field in circumstellar envelopes.Comment: Accepted for publication in The Astrophysical Journal Letters. 10 pages, 3 figure

The shaping effect of collimated fast outflows in the Egg nebula

We present high angular resolution observations of the HC$_3$N J=5--4 line from the Egg nebula, which is the archetype of protoplanetary nebulae. We find that the HC$_{\rm 3}$N emission in the approaching and receding portion of the envelope traces a clumpy hollow shell, similar to that seen in normal carbon rich envelopes. Near the systemic velocity, the hollow shell is fragmented into several large blobs or arcs with missing portions correspond spatially to locations of previously reported high--velocity outlows in the Egg nebula. This provides direct evidence for the disruption of the slowly--expanding envelope ejected during the AGB phase by the collimated fast outflows initiated during the transition to the protoplanetary nebula phase. We also find that the intersection of fast molecular outflows previously suggested as the location of the central post-AGB star is significantly offset from the center of the hollow shell. From modelling the HC$_3$N distribution we could reproduce qualitatively the spatial kinematics of the HC$_3$N J=5--4 emission using a HC$_3$N shell with two pairs of cavities cleared by the collimated high velocity outflows along the polar direction and in the equatorial plane. We infer a relatively high abundance of HC$_3$N/H$_2$ $\sim$3x10$^{-6}$ for an estimated mass--loss rate of 3x10$^{-5}$ M$_\odot$ yr$^{-1}$ in the HC$_3$N shell. The high abundance of HC$_3$N and the presence of some weaker J=5--4 emission in the vicinity of the central post-AGB star suggest an unusually efficient formation of this molecule in the Egg nebula.Comment: 22 pages, 6 figures, submitted to the Astrophysical Journa

Water in Emission in the ISO Spectrum of the Early M Supergiant Star mu Cephei

We report a detection of water in emission in the spectrum of the M2 supergiant atar mu Cep (M2Ia) observed by the Short Wavelength Spectrometer (SWS) aboard Infrared Space Observatory (ISO) and now released as the ISO Archives. The emission first appears in the 6 micron region (nu2 fundamental) and then in the 40 micron region (pure rotation lines) despite the rather strong dust emission. The intensity ratios of the emission features are far from those of the optically thin gaseous emission. Instead, we could reproduce the major observed emission features by an optically thick water sphere of the inner radius about two stellar radii (1300Rsun), Tex = 1500K, and Ncol (H2O) = 3.0E+20/cm2. This model also accounts for the H2O absorption bands in the near infrared (1.4, 1.9, and 2.7 micron) as well. The detection of water in emission provides strong constraints on the nature of water in the early M supergiant stars, and especially its origin in the outer atmosphere is confirmed against other models such as the large convective cell model. We finally confirm that the early M supergiant star is surrounded by a huge optically thick sphere of the warm water vapor, which may be referred to as MOLsphere for simplicity. Thus, the outer atmosphere of M supergiant stars should have a complicated hierarchical and/or hybrid structure with at least three major constituents including the warm MOLsphere (T about 1.0E+3K) together with the previously known hot chromosphere (T about 1.0E+4K) and cool expanding gas-dust envelope (T about 1.0E+2K).Comment: 14 pages, 5 postscript figures, to appear in ApJ

Design of a Front-End for Satellite Receiver

This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals

VulCurator: A Vulnerability-Fixing Commit Detector

Open-source software (OSS) vulnerability management process is important nowadays, as the number of discovered OSS vulnerabilities is increasing over time. Monitoring vulnerability-fixing commits is a part of the standard process to prevent vulnerability exploitation. Manually detecting vulnerability-fixing commits is, however, time consuming due to the possibly large number of commits to review. Recently, many techniques have been proposed to automatically detect vulnerability-fixing commits using machine learning. These solutions either: (1) did not use deep learning, or (2) use deep learning on only limited sources of information. This paper proposes VulCurator, a tool that leverages deep learning on richer sources of information, including commit messages, code changes and issue reports for vulnerability-fixing commit classifica- tion. Our experimental results show that VulCurator outperforms the state-of-the-art baselines up to 16.1% in terms of F1-score. VulCurator tool is publicly available at https://github.com/ntgiang71096/VFDetector and https://zenodo.org/record/7034132#.Yw3MN-xBzDI, with a demo video at https://youtu.be/uMlFmWSJYOE.Comment: accepted to ESEC/FSE 2022, Tool Demos Trac