Modern languages in comprehensive schools

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An investigation into the linguistic and methodological origins and the process of curricular dissemination of Graded Objectives and Tests in modern language teaching, with particular reference to Cleveland Education Authority

An investigation into the linguistic and methodological origins and the process of curricular dissemination of Graded Objectives and Tests in modern language teaching, with particular reference to Cleveland Education Authority. Alma Hellaoui/ Submitted for M.A., 1986. The subject of this thesis is curriculum innovation in the teaching and learning of modern languages with particular reference to Cleveland L.E.A. The innovation is mainly concerned with the initiation, development and implementation of the Graded Objectives Movement, the Defined Content Syllabus and Graded Tests Schemes. This innovation is of particular interest since it represents a process which has evolved from the grass-roots upwards, from the dissatisfaction of classroom teachers, to changes in the teaching and learning of modern languages, to the revision of examination syllabuses. The purpose of this thesis is to describe how and why the movement developed and to examine in particular how Cleveland L.E.A. became involved in it and adopted it in its own way. Furthermore this thesis places what was a practical, pragmatic innovation in its theoretical context and assesses its relevance therein, since in the process of this kind of innovation it is sometimes easy to overlook theoretical issues. The methods for examining the innovation in Cleveland were analysis of the documents produced in the education authority and questionnaires, interviews and discussion with Cleveland teachers. (The interviews were informal and recorded on cassette). The information collected was analysed and from it it was possible to build up a picture of what has happened during the last ten years, what is happening today and how teachers have reacted to and evaluate the effects of the innovation. This curriculum innovation in the communicative teaching and learning of modern languages has engendered many radical changes. These have advantages which have affected various parts of the whole curriculum: these spring mainly from the emphasis on communication in modern languages since communication skills have ‘rub off effects in many subject areas. Hence now the communicative style of the teaching and learning of modern languages has its place in the comprehensive curriculum not just by right but by merit

Analytical modelling of congestion for 6LoWPAN networks

The IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) protocol stack is a key part of the Internet of Things (IoT) where the 6LoWPAN motes will account for the majority of the IoT ‘things’. In 6LoWPAN networks, heavy network traffic causes congestion which significantly affects the overall performance and the quality of service metrics. In this paper, a new analytical model of congestion for 6LoWPAN networks is proposed using Markov chain and queuing theory. The derived model calculates the buffer loss probability and the channel loss probability as well as the number of received packets at the final destination in the presence of congestion. Also, we calculate the actual wireless channel capacity of IEEE 802.15.4 with and without collisions based on Contiki OS implementation. The validation of the proposed model is performed with different scenarios through simulation by using Contiki OS and Cooja simulator. Simulation results show that the analytical modelling of congestion has an accurate agreement with simulation

Enhancing the Performance of UAV Communications in Cellular Networks

The use of cellular networks as a communication infrastructure for Unmanned Aerial Vehicles (UAVs) has become the current trend. This would mainly enable beyond visual line-of-sight applications and allow UAVs to benefit from the latest evolutions achieved in cellular networks.Despite the advantages that cellular networks can bring to UAVs, several issues still need to be addressed. Indeed, cellular networks are deployed to serve ground user equipment (UEs), whereas UAVs' aerial communications are characterized by different channel conditions. Field evaluations have shown that flying UAVs can experience poor link quality, or even negatively affect ground communication. In addition, UAV applications can be deployed in a challenging environment characterized by different types of QoS (Quality of Services). For instance, UAVs can be deployed to provide network connectivity to ground devices, whereas each one of the latter requires sending two types of traffics with different QoS, at the same time. Furthermore, the consideration of cellular networks for UAVs can bring more opportunities that merit to be explored to enhance the communications, mainly in terms of taking advantage of the presence of several UAVs and Mobile Network Operators (MNOs). The main objective of the dissertation is to contribute to enhancing the performance of UAV communications in cellular networks. The contributions of this dissertation can be divided into six categories. First, as aerial communication presents different channel conditions, we are interested in modeling UAV communications in cellular networks and deriving expressions that define the performance indicators. All the contributions build from these expressions, and target performing network optimization to enhance UAV communications in cellular networks. Second, we consider a cellular network deployed to serve both UEs and UAVs, and we investigate their co-existence by enhancing their underlying performances. Next, we focus on supporting the co-existence of several QoS types in UAV communications. To this end, we consider the scenario where UAVs are deployed to provide network connectivity to ground devices, where each one of the latter requires two different QoS types. In the fourth and the fifth categories, we focus on new opportunities that cellular networks can bring to UAV communications. In particular, we investigate the possibility of taking advantage of the presence of several UAVs and MNOs in a way to enhance the performance of UAV communications. Finally, we explore the use of machine learning in order to enable fast optimization and enhance the performance of UAV communications. All the contributions of this dissertation have been validated with a series of performance evaluations

TAS-IoT: Trust-Based Adaptive Security in the IoT

International audienc

Threshold Yoking/Grouping Proofs Based on CP-ABE for IoT Applications

International audience—The Internet of Things (IoT) introduces a new vision in which objects are connected to the network. This paradigm is receiving much attention of the scientific community and it is applied in many fields. In some cases, it is useful to prove that a number of objects are simultaneously present in a group. For instance, a client might want to authorize NFC payment with his mobile only if k of his devices are present to ensure that he is the right person. This principle is known as yoking/grouping Proofs. However, existing grouping schemes are mostly designed for RFID systems and don't fulfill the IoT characteristics. In this paper, we tackle this issue and propose a threshold yoking/grouping proof for IoT applications. Our scheme uses the Ciphertext-Policy Attribut-Based Encryption (CP-ABE) protocol to encrypt a message so that it can be decrypted only if at least k nodes are simultaneously present. A security analysis and performance evaluation is conducted to show the effectivenesses of our proposal solution

Towards using Deep Reinforcement Learning for Connection Steering in Cellular UAVs

Funding Information: ACKNOWLEDGMENT This work was partially supported by the European Union’s Horizon 2020 Research and Innovation Program through the 5G!Drones Project under Grant No. 857031. It was also supported in part by the Academy of Finland 6Genesis project under Grant No. 318927. Publisher Copyright: © 2021 IEEE. | openaire: EC/H2020/857031/EU//5G!DronesThis paper investigates the fundamental connection steering issue in cellular-enabled Unmanned Aerial Vehicles (UAVs), whereby a UAV steers the cellular connection across multiple Mobile Network Operators (MNOs) for ensuring enhanced Quality-of-Service (QoS). We first formulate the issue as an optimization problem for minimizing the maximum outage probability. This is a nonlinear and nonconvex problem that is generally difficult to be solved. To this end, we propose a new approach for solving the optimization problem based on Deep Reinforcement Learning (DRL), considering two important reinforcement learning algorithms (i.e., Deep Q-Learning (DQN) and Advantage Actor Critic (A2C)). Simulation results show that under the proposed approach, the UAVs can make optimal decisions to select the most suitable connection with MNOs for achieving the minimization of the maximum outage probability. Furthermore, the results also show that in our new approach, the A2C-based algorithm is better than the DQN-based one, especially when the number of MNOs increases, while the DQN-based algorithm can be executed in a shorter time.Peer reviewe

Energy Efficiency in Security of 5G-Based IoT: An End-to-End Adaptive Approach

The challenging problem of energy efficiency in security of the Internet of Things (IoT) is tackled in this article. The authors consider the upcoming generation of mobile networks, 5G, as a communication architecture for the IoT. The concept of adaptive security is adopted, which is based on adjusting the security level as per the changing context. It has the potential of reducing energy consumption by adapting security rather than always considering the worst case, which is energy consuming. The consideration of 5G introduces new dynamics that can be exploited to perform more adaptation. The proposed solution introduces an intelligence in the application of security, from the establishment phase to the use phase (end-to-end). The security level related to the used cryptographic algorithm/key is adapted for each node during the establishment phase, so to match with the duration of the provided services. A new strategy is formulated that considers both IoT and 5G characteristics. In addition, a solution basedon the framework of the coalitional game is proposed in order to associate the deployed objects with the optimized security levels. Moreover, the application of security is also adapted during the use phase according to the threat level. Trust management is used to evaluate the threat level among the network nodes, while existing works focus on performing the adaptation during the use phase. The proposed approach achieves more adaptation through the consideration of both IoT and 5G dynamics. The analysis and performance evaluations are conducted to show the effectiveness of the proposed end-to-end approach.Peer reviewe