A Long-Range Wide Area Network (LoRaWAN) is one of the most efficient technologies and is widely adopted for the Internet of Things (IoT) applications. The IoT consists of massive End Devices (EDs) deployed over large geographical areas, forming a large environment. LoRaWAN uses an Adaptive Data Rate (ADR), targeting static EDs. However, the ADR is affected when the channel conditions between ED and Gateway (GW) are unstable due to shadowing, fading, and mobility. Such a condition causes massive packet loss, which increases the convergence time of the ADR. Therefore, we address the convergence time issue and propose a novel ADR at the network side to lower packet losses. The proposed ADR is evaluated through extensive simulation. The results show an enhanced convergence time compared to the state-of-the-art ADR method by reducing the packet losses and retransmission under dynamic mobile LoRaWAN network.
LoRaWAN is renowned and a mostly supported technology for the Internet of Things, using an energy-efficient Adaptive Data Rate (ADR) to allocate resources (e.g., Spreading Factor (SF)) and Transmit Power (TP) to a large number of End Devices (EDs). When these EDs are mobile, the fixed SF allocation is not efficient owing to the sudden changes caused in the link conditions between the ED and the gateway. As a result of this situation, significant packet loss occurs, increasing the retransmissions from EDs. Therefore, we propose a Resource Management ADR (RM-ADR) at both ED and Network Sides (NS) by considering the packet transmission information and received power to address this issue. Through simulation results, RM-ADR showed improved performance compared to the state-of-the-art ADR techniques. The findings indicate a faster convergence time by minimizing packet loss ratio and retransmission in a mobile LoRaWAN network environment.
Abstract
The aim of this study is to find out the misconceptions about the photosynthesis and respiration processes and their causes among elementary levels of Science students. When students come into the classrooms they have a lot of misconceptions/ alternative ideas based on their previous understanding, learning experiences, and observation of their surroundings. It started from the initial level where children construct their knowledge by observing the world. These ideas, beliefs, observations, and make their preconceptions. This research had been conducted to find out the misconceptions about respiration and photosynthesis and their causes. The nature of this research study is an exploratory case study from the private school of Sukkur, Sindh. Semi-structured interviews and unstructured observations were done to conduct the data for this research study to investigate the misconceptions in Science. One private school was selected for this research in Sukkur. The sample size for this research was eight students in class eight and two science teachers. Four girls and four boys were chosen and two teachers, one male, and one female were chosen to conduct the data. The semi-structured interviews were recorded by teachers and students and then translated and transcribed. After that, read the code and identify the patterns. The codes were assigned to the responses of participants based on similarities and differences. The themes were extracted from the coding of the responses and categorized into seven themes and one sub-theme. It was determined that students had many misconceptions about photosynthesis and respiration processes.
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