Computer Self-efficacy and Perceptions of Online Learning during the Covid-19 Lockdown in Iran High Schools

إن النقلة الفجائية إلى التدريس عبر الإنترنت بعد انتشار كوفيد-19 وضعت متعلمي اللغة الانجليزية أمام تحديات عدة. وللنجاة أمام هذه التحديات التعليمية، كان لابد من أن تُؤثر قدراتهم الموجهة نحو التكنولوجيا على فهمهم وتصورهم وممارساتهم في بيئات التعلم عبر الإنترنت. تصف الدراسة الحالية تجربة التعليم عبر الإنترنت لطلاب الصف الثاني عشر الثانوي في إيران خلال فترة الجائحة في ضوء مستوى كفاءتهم الذاتية الحاسوبية (CSE). ولهذا الهدف استجاب 110 طلاب على استبانة الكفاءة الذاتية الحاسوبية. أشارت النتائج إلى درجة متوسطة إلى منخفضة من الكفاءة الذاتية الحاسوبية بين المشتركين. طبقاً للنتائج التي تم الحصول عليها قُسّم المشاركون إلى مجموعتين وهي مجموعة ذات كفاءة ذاتية منخفضة ومجموعة ذات كفاءة ذاتية مرتفعة، وطُلب منهم أن يفكّروا ملياً في تجربتهم في التعليم عبر الإنترنت خلال الجائحة بالإجابة على ثمانية أسئلة  ضمن نموذج مقالات للتأمل الذاتي. تم تحليل التأملات الذاتية لكلا المجموعتين بشكل منفصل، وتم استخراج الأنماط المتكررة. أظهرت النتائج عدة قواسم مشتركة وتناقضات بين الطلاب من ذوي الكفاءة الذاتية الحاسوبية المرتفعة والمنخفضة مع أخذ تجربتهم في التعلم عن بعد خلال إغلاق كوفيد-19بعين الاعتبار. تقدم النتائج نصائح تربوية لتحسين الكفاءة الذاتية الحاسوبية بين طلاب الثانوية.The sudden shift to online teaching following the outbreak of COVID-19 has confronted English language learners with numerous challenges. The students’ perceptions and practices in online learning environments might be influenced by their technology-oriented abilities to survive in the current educational predicament. The current study elucidated the 12th-grade high school students’ online learning experiences in a developing country during the global pandemic in light of their computer self-efficacy (CSE) level. To this end, a total number of 110 students completed the computer self-efficacy scale. The results indicated a moderate to low level of computer self-efficacy among the participants. According to the obtained scores, they were divided into low-CSE and high-CSE groups and asked to ruminate over their online learning experiences during the pandemic by answering eight questions in the form of self-reflection essays. The self-reflections of the two groups were separately analysed, and the recurrent themes were extracted. The results revealed several commonalities and discrepancies between the low- and high- CSE students considering their distant learning experiences within the COVID-19 lockdown. The findings provide pedagogical recommendations for enhancing online learning efficiency among high school students

Time Hopping:An Efficient Technique for Reliable Coexistence of TSCH-Based IoT Networks

Escalation in the use of Internet of Things (IoT) devices gives rise to the number of networks operating in the license-free 2.4-GHz frequency band. This prepares the ground for networks to experience interference from coexisting networks and thus performance degradation. Time-slotted channel hopping (TSCH), as an operational medium access mode of the IEEE 802.15.4 technology, was introduced to ensure the reliability of IoT networks when they undergo coexistence. It uses frequency hopping as a protective strategy against long-term packet losses due to interference. However, when several independent TSCH networks coexist, they are prone to interfere with one another. In extreme scenarios, coexisting TSCH networks may block links of one another for an extended duration of time, leading to application failure. In this article, we propose a novel technique called time hopping to secure the reliability of coexisting TSCH networks. The developed technique synchronously and periodically alters the timing of nodes within a TSCH network to avoid coexisting TSCH networks from getting stuck in extreme coexistence scenarios and long-term continuous collisions. We evaluate the effectiveness of the proposed technique through extensive simulations. The results clearly show that the proposed time hopping technique substantially improves the worst case internetwork collision ratio, with as much as 50% improvement in some tested scenarios. The implementation of the technique is very simple, with almost no communication or computation overhead for the constrained wireless nodes; it is done and tested on real nodes for proof of concept

Utjecaj metode sinteze na katalitičko reformiranje kerozina

Ni/Y samples were prepared by various synthesis methods to investigate the catalyst performance in the reforming of kerosene. Properties of the samples were characterised using XRD, BET, NH3-TPD, and FTIR techniques. Analysis of the products revealed that more isoalkanes were obtained by the sol-gel method (37.3 %), but the deposition method produced higher aromatic content (32.7 %). Ultimately, the production of 75.81 % jet fuel with a standard range of aromatics (10.70 %) and higher naphthenes (19.3 %) over impregnated catalyst led us to conclude that lower Brønsted acid sites inhibited the occurrence of side reactions and produced more jet fuels. This work is licensed under a Creative Commons Attribution 4.0 International License.Uzorci Ni/Y pripremljeni su različitim metodama sinteze da bi se ispitala učinkovitost katalitičkog reformiranja kerozina. Svojstva uzoraka karakterizirana su tehnikama XRD, BET, NH3-TPD i FTIR. Utvrđeno je da je više izoalkana nastaje sol-gel metodom (37,3 %), dok se metodom deponiranja dobiva veći udio aromata (32,7 %). Proizvodnja 75,81 % mlaznog goriva standardnog udjela aromata (10,70 %) i viših naftena (19,3 %) na impregniranom katalizatoru rezultirala je zaključkom da manji broj Bronstedovih kiselinskih mjesta koči pojavu usporednih reakcija te nastaje više mlaznog goriva. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna