48 research outputs found

    Post-adjunct reading comprehension questions and meaning construction : a case of gender study

    Full text link
    This article explicates on how the post-adjunct reading comprehension questions existing in the Iranian high school and pre-university English textbooks affect the comprehension of the related students. It further purports to see if there is a significant gender difference in the comprehension of reading texts by these student groups. To this end, 240 third-grade high school and pre-university students (equal number of male and female) participated in this investigation. The results demonstrated a significant superiority in the subjects’ reading comprehension when they answered the texts with the post-adjunct reading comprehension questions, designed by the researchers for this purpose. The results also showed non-significant gender disparities in the comprehension of given texts

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

    Get PDF
    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

    Performance enhancement of photovoltaic-thermal modules using a new environmentally friendly paraffin wax and red wine-rGO/H2O nanofluid

    Get PDF
    Photovoltaic/thermal systems are one of the most efficient types of solar collectors because they absorb solar radiation and generate electricity and heat simultaneously. For the first time, this paper presents an investigation into the impact of red wine-rGO/H2O nanofluid and paraffin wax on the thermohydraulic properties of a photovoltaic/thermal system. The study focuses on three innovative nonlinear arrangements of the serpentine tubes. The effects of these materials and configurations are analyzed through numerical simulations. To improve the performance, environmentally friendly materials, including red wine-rGO/H2O nanofluid and paraffin wax, have been used. Various performative parameters such as electrical and thermal efficiency of the photovoltaic/thermal system, exergy, and nanofluid concentration were investigated. The results demonstrated a significant enhancement in the system’s performance when using innovative serpentine tubes instead of simple tubes for the fluid flow path. The use of paraffin C18 increases electrical efficiency, while the use of paraffin C22 improves thermal efficiency. Moreover, the incorporation of phase change materials along with the utilization of innovative geometries in the serpentine tube led to a notable improvement in the outlet temperature of the fluid, increasing it by 2.43 K. Simultaneously, it substantially reduced the temperature of the photovoltaic cells, lowering it by 21.55 K. In addition, the new model demonstrated significant improvements in both thermal and electrical efficiency compared to the simple model. Specifically, the maximum thermal efficiency improvement reached 69.2%, while the maximum electrical efficiency improvement reached 11.7%

    The Effectiveness of Intravenous lidocaine in Burn Pain Relief: A Randomized Double-Blind Controlled Trial

    Get PDF
    Objectives: Poor pain control in burn patients as a great public health problem disrupts the healing and rehabilitation process and results in several adverse outcomes. The aim of this study was to investigate the efficacy and safety of intravenous lidocaine in reducing the pain of burn injuries. Materials and Methods: From August 2014 to March 2015, 66 eligible burn patients participated in the study and were randomly divided into two groups of lidocaine (L) and placebo (P). In group L, lidocaine 2% was injected at a bolus dose of 1.5 mg/kg followed by infusion at the dosage of 1.5 mg/kg/h, and in group P, saline was administrated. Pain severity was measured during 24 hours at baseline and 1, 2, 4, 8, 12, 16, 20, 24 hours after intervention based on Numerical Rating Scale (NRS-11). Morphine consumption, Ramsay score, and side effects were also documented. Results: Finally the data from 60 patients were analyzed. Comparing baseline with 24 hours after intervention, NRS-11 scores decreased from 7.12±1.42 to 3.33±0.76 (P<0.001) in group P and from 6.45±1.02 to 2.50±0.72 (P<0.001) in group L. Moreover, the mean of NRS scores during 24 hours in the lidocaine group was significantly lower compared to the placebo group, 3.93±0.72 vs 4.73 ±1.14, (P=0.03). The mean amounts of morphine consumption in group L were significantly lower compared to group P, 14.41 ± 4.86 vs 21.07±6.86, (P=0.001). The mean of Ramsay score in group L was significantly lower compared to group P, 1.38±0.59 vs 1.45±0.6, (P=0.014). Conclusions: This study revealed that intravenous lidocaine was an effective and safe drug for pain reduction in burn patients

    Coexistence Analysis of Multiple Asynchronous IEEE 802.15.4 TSCH-Based Networks

    No full text
    Low-power Wireless Sensor Networks (WSNs) play a key role in realization of the Internet-of-Things (IoT). Among others, Time Slotted Channel Hopping (TSCH) is a Medium Access Control (MAC) operational mode of the IEEE 802.15.4 standard developed for communications in short range IoT networks. TSCH provides high level reliability and predictability by its channel hopping mechanism and time division channel access nature. In many applications, a number of TSCH networks may coexist in the same neighborhood. Several vehicles close to one another, each including a TSCH network for its in-vehicle communications, serve as an example. Since such networks are running independent of one another, they are not expected to be synchronized in time, and they are not scheduled to operate in exclusive frequency channels. This may lead to inter-TSCH interferences deteriorating the reliability of the networks, which is an important requirement for many IoT applications. This paper analyzes the impact of multiple asynchronous TSCH networks on one another. An analytical model is developed that estimates the chance of such interferences, and the expectation of the number of affected TSCH channels when a number of them are in the vicinity of one another. The developed model is verified using extensive simulations and real-world experiments. Also, a scalable and fast multi-TSCH coexistence simulator is developed that is used to get insight about coexistence behaviors of any number of TSCH networks with various configurations

    Computerized Analysis of Digital Photographs for Evaluation of Tooth Movement

    No full text
    Objectives: Various methods have been introduced for evaluation of tooth movement in orthodontics. The challenge is to adopt the most accurate and most beneficial method for patients. This study was designed to introduce analysis of digital photographs with Auto- CAD software as a method to evaluate tooth movement and assess the reliability of this method. Materials and Methods: Eighteen patients were evaluated in this study. Three intraoral digital images from the buccal view were captured from each patient in half an hour inter- val. All the photos were sent to AutoCAD software 2011, calibrated and the distance be- tween canine and molar hooks were measured. The data was analyzed using intraclass cor- relation coefficient. Results: Photographs were found to have high reliability coefficient (P > 0.05). Conclusion: The introduced method is an accurate, efficient and reliable method for eval- uation of tooth movement

    An empirical study of the performance of IEEE 802.15.4e TSCH for wireless body area networks

    No full text
    Wireless Body Area Networks (WBANs) have made their way into many smart and ubiquitous healthcare and wellness applications. A low-power, efficient, and reliable communication protocol is of paramount importance for the success of WBANs in satisfying the requirements of the health applications. The IEEE 802.15.4 standard is always one of the main options due to its efficiency and low-complexity. However, it suffers from the impact of other wireless technologies using the same frequency band such as WiFi and Bluetooth. Time Slotted Channel Hoping (TSCH) is an operational mode of the IEEE 802.15.4e standard, which is originally developed for reliable industrial wireless networks. TSCH has Time Division Multiple Access (TDMA) and frequency hopping features, which increase the network robustness against effects such as noise, interference, and multi-path fading. This paper proposes to exploit TSCH for communications in WBANs, and studies its performance. The features of TSCH like power efficiency, TDMA-based operation, and heterogeneity support fit very well with the requirements of many health monitoring applications. The performance of the TSCH standard for WBAN communications is investigated through real-world experiments in various conditions. The results show that TSCH outperforms the basic IEEE 802.15.4 standard in terms of communication reliability against interferences from coexisting wireless devices
    corecore