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The web has spurred our imagination as to how education can be drastically transformed and improved through the adoption of Information and Communications Technology (ICT) and the use of simulations quickly became a wildly disputed topic. This kind of simulations are considered as a significant pedagogical innovation especially in the electromagnetics course where it is possible to concretize , via a set of interactive simulations, some experiments that are inaccessible in real life. The aim of interactive simulations is to enhance the student’s understanding by providing him a meaningful insight into the studied notions, phenomena, concepts, laws and models. The design of didactic simulations is constrained by both technological choices, learning theories and numerical models which should guarantee a minimal execution time, a better stability and an acceptable precision. Our goal in this work is to design didactic simulations for electromagnetism using a numerical Element Oriented Method (EOM). The proposed EOM meets the needs of speed, accuracy and ensure bet-ter dynamical and visual interpretations of the basic laws of electromagnetic. Moreover, these applications are not only available for traditional training in the classroom but also for new training platforms provided by digital technologies such as web-based training, e-learning and m-learning.

Most of the real world problems involving decisions are part of a complex environment, where multiple objectives and points of view have to be taken into account and the diversity of value systems are present. This observation motivated our study, which focuses on the development and/or validation of mathematical models and computer tools for complex-problems evaluation via expert knowledge. As an example of a complex situation, the evaluation of catch-up sessions is treated. Usually, in a catch-up evaluation the final score is either the average or the maximum value and the choice is in most cases unjustified. Thus, the evaluation of the objectives achievement could only be in turn deficient. Using our new intelligent evaluation system based on Knowledge Based Expert Systems (KBES) and fuzzy logic lead us to discover new models for evaluating such complex problems. The principle of this system is to reproduce the cognitive mechanisms of an expert in evaluation.

In this paper, we present a study of the behavior of new RF-exposimeter measurement methods based on linear regression as a function of frequency and distance change. For this, we use a realistic human model (Gustav) exposed to the radiation of a base station antenna. The frequency bands used are GSM, DCS and LTE-Wimax. The distance varies from the near field zone to the far field zone. The errors induced by the human body have been evaluated. The study showed that errors increase with frequency and decrease in Far Field zone. But in general, the proposed methods have a good response to variations in frequency and distance.

Calibration of RF exposimeter is a serious problem when conventional measurement methods are used, especially when the morphology of the user, workers or public, changes a lot. In this paper we present a study of the behavior of new measurement methods based on linear regression with respect to morphological change. For this we use three models: Child, Gustav and Emma of different sex, age and dimensions. The study is conducted in the near field for a base station antenna at the DCS band. The study showed a low dependence of the proposed methods on morphology.

In this paper we present a novel methodology for time-domain characterization of a full anechoic chamber using the finite integral method. This approach is considered fast, accurate and not intensive for computer resources. The validation of this approach is carried out on CST-microwave studio for a full anechoic chamber intended for antennas measurement applications and electromagnetic exposure evaluation for cellular network. Low, medium and high gain sources are used in this study. The simulations are realized on a personal computer of medium performances (i7 CPU and 16 GB of RAM). The stability and the convergence of our approach are obtained thanks to local mesh and auto-regressive linear filtering techniques. The minimization of the simulation time is based on use of the Huygens sources in the place of the antennas. The maximum error of the chamber as well as the wave depolarization into the chamber are at one with the previous work and the catalogs of the principles chambers manufacturers for the proposed tests in this paper. The Full simulations time is about 15 hours in average.

The Personal Dosimeter is a portable device that allows measurement of electromagnetic field levels. In this work we propose a new method for non-invasive evaluation of the whole body averaged body specific absorption rate of the human body (${SAR}_{wba}$) from only the personal dosimeter measurement. This new method is based on linear regression to reduce errors due to the presence of the human body on the measurement. The results show a SAR assessment with very low error rates in the order of 5%, a reduction in the average error of 5 times for a morphology of a middle adult man and 9 times for a morphology of a child of 10 years old.

In this work, we present a study of the behavior of new measurement methods based on linear regression with respect to morphological, frequency and separation distance change. For this we use three models: Child, Gustav and Emma of different sex, age and dimensions.The study is conducted in the near field for a base station antenna at the DCS band. The study showed a low dependence of the proposed methods on morphology. After this, we study the frequency dependence of the RF exposimeter error and the effect of the distance between the sources and the human body. The frequency bands used are GSM, DCS and LTE-Wimax. The distance varies from the near field zone to the far field zone. The study showed that errors increase with frequency and decrease in Far Field zone. The main original contribution of the proposed approach is that the procedure of calibration of the personal exposimeter is based on statistical analyzes taking into account morphology, frequency and distance between the body and the source of exposure.

Supported by new technologies in education, didactic simulation has become an important research issue. It constitutes a genuine educational innovation for all training platforms. In particular, in electromagnetism and electronics, real didactic progress should be concretized by the interactive simulation of certain experiences that are often inaccessible in reality by the animated visualization of different abstract concepts. However, their design is constrained by technological choices, learning theories and numerical models which will ensure both minimal execution time, better stability and acceptable accuracy. Based on a topological approach to electromagnetism, a key to a successful numerical object-oriented method, we present a new "Element Oriented Model" (EOM). This method allows to generalize the FDTD method and the non-standard NS-FDTD method and to develop two new and faster algorithms. It is thus proposed as a foundation to carry out interactive simulations that can be described as "simulated experiments" via object-oriented numerical methods.

The number and increasing complexity of attacks against MANETs have grown significantly in recent years. While many security proposals have been developed. However, these proposals suffer from the problems of tests and evaluations. Among these solutions, the Intrusion Detection Systems (IDS) that can act as defense mechanisms. However, this last poses serious problems for its evaluators that need classify the attacks to select case test. In this paper, we make a thorough analysis of existing attack classifications in order to determine whether they could be helpful in selecting attack test cases. Based on our analysis, we construct a new scheme to classify attacks relying on those attributes that appear to be the best classification criteria. We also apply the Classification Tree Method (CTM) to select test-case to attack. Finally, we use the Classification Tree Editor (CTE) tool to generate and select test-case.

The studies presented in this paper are part of the problematic that aims the simulation and characterization of an anechoic chamber. A new approach based on the Finite Integral Method (FIT) was presented and evaluated for modeling a full anechoic chamber for antenna near/far-field measurement. The probe as well as the Antenna Under Test (AUT) are replaced by their Huygens sources calculated separately. This new technique has allowed us to gain in terms of computing resources and also to reduce the simulation time, compared to other solutions. The convergence and the stability of the proposed method are guaranteed by an autoregressive filter and an adaptive mesh. The results obtained show that the maximum error as well as the depolarization of the wave in the Quiet Zone (QZ) of the chamber are of the order of 1 dB. The calculation time is 15 h, which represents a gain of 90%.

As the use of electromagnetic fields (EM) by radiofrequency (RF) has increased along with increased use of mobile phones, the potential health risks have also been widely discussed. In this study, the effect of fixing metal braces on teeth, was examined by giving the variation of the specific absorption rate (SAR) distribution and antenna parameters. Three halfwave dipole antennas were used as the exposure source for the GSM-900, DCS-1800 and 5G-3600 Mhz frequency bands, in the presence of a three-dimensional 3-D heterogeneous model of the human head named Zubal. All simulations are performed with CST Microwave Studio 2017.

International audience; Objective: As well known, using a single body worn sensor exposimeter introduces systematic errors on the measurement of the incident free space electric field strength. This is because the body creates around it high, intermediate and low level field zones, which depend on the direction of arrival of the incident field. The goal of this work is to propose an efficient method for the reduction of these errors. Methods: After classifying the perturbations induced by the body on the measured electric and magnetic fields thanks to realistic numerical simulations, we then propose a two-sensor setup in conjunction with simple semi-empirical correction formulas, in order to compensate these perturbations. Results: At 942 MHz, when the two sensors are placed in any opposite sides of the body at chest height, the worst case, maximum and average errors respectively decrease to 12% and 3% compared to 83% and 22% for measurement techniques using a single sensor, or 32% and 11% when using the average value of the measurements. Conclusion: The error related to the measurement in the presence of the body was significantly reduced by the proposed method making use of two opposite sensors, E-field and H-field at the chest. Significance: The conformity of exposure to EMF in terms of reference values according to the ICNIRP is given in the abscence of the human body. The interest of this work lies in the reduction of the errors made when measuring the field in the presence of the body.

In order to maintain the training quality and ensure efficient learning, the introduction of a scalable and well-adapted evaluation system is essential. An adequate evaluation system will positively involve students in the evaluation of their own learning, as well as providing teachers with indicators on the student's strengths, the specific encountered difficulties and the false or misunderstood studied parts. In this context, we present, in this article, a novel intelligent evaluation methodology based on fuzzy logic and knowledge based expert systems. The principle of this methodology is to reify abstract concepts of a human expertise in a numerical inference engine applied to evaluation. It reproduces, therefore, the cognitive mechanisms of evaluation experts. An im-plementation example is presented to compare this method with the classical one and draw conclusions about its efficiency. Furthermore, thanks to its flexibility, different kinds of extensions are possible by updating the basic rules and adjusting to possible new architectures and new types of evaluation.

The teaching of transmission line theory in electrical engineering courses must be tailored to an audience which is increasingly reluctant to adhere to abstract disciplines. In our opinion, the best solution to make transmission line courses more attractive is to offer practical applications and intensively use of mathematical computer-aided teaching tools to overcome, at the beginning, the difficulties linked to the theory. Indeed, transmission line theory comes alive when the travelling waves are animated on a screen (smartphone, tablets, laptop, etc.). Fundamental concepts such as “progressive wave”, “reflected wave” and “load matching” could be easily demonstrated in the classroom or at home. Transmission line simulations are applied to problems using connections to shunt, open, matched and unmatched loads, and show how the signal waveforms arise from one end to another. The proposed Android-based animations are used with a sinusoidal generator to illustrate the evolution to the sinusoidal steady state and allow learners to easily handle the corresponding Smith chart. Students are encouraged to run those applications at home as a computational laboratory to verify their solutions to homework problems. This article introduces simple Android-based virtual tools for the investigation and visualization in real time of waves traveling along a terminated finite-length transmission line, without and with faults between the source and the load. The package can be used as an educational tool in various lectures or homework to aid teaching high frequency electronics and transmission lines theory.

The correct evaluation of human exposure to electromagnetic fields is necessary in daily life because of the increase in RF devices and their proximity to the user. This assessment can be performed by using a personal dosimeter which measures the level of the electromagnetic field with the presence of the human body. The aim of this work is to present a correction law to reduce the measurements errors of a RF dosimeter due to the presence of the human body. To evaluate the performance of this law we used two errors: the Body Reflection Errors and Body Shadowing Errors. Two approaches combining electric and magnetic fields are studied in near and far field situations. Simulation results show that the application of the proposed correction law, which uses two diametrically opposite measuring point around the body, significantly reduces measurement error. Assessing the human exposure in near and far fields situations reassures users and especially the workers they are in an environment that respect the laws and standards of exposure to electromagnetic waves.

In this paper, we present some interactive simulations developed mainly for educational purposes in physics, mathematics, and engineering. A new horizon of understanding some concepts via interactive animations has opened a new research dimension in the learning theory. In this work, our interest is focused on the design of interactive and didactic simulations for teaching and learning differential equations. The code is written in ActionScript/Flash to enjoy all the benefits of this technology in the multimedia field, Internet and mobile phones (smartphones and tablets). This powerful tool stimulates students' interest to understand/learn abstract mathematical concepts in physics. These simulations provide additional insight for concepts that need a lot of resources and time. These simulations are applied in e-learning environments and engineering education.

In sciences education, experimental methods are crucial for a better understanding of basic physical phenomena. Moreover, practical sessions and experimental methods give students an opportunity to develop their perceptions and to increase their interest in a given topic. In the electronic educational curriculum, one of the keys for a successful achievement of educational goals is the good comprehension and perception of electromagnetic fields and wave propagation phenomena especially in the high frequency domain. In this scope and taking advantages of the progress of a new stage of distance learning known as mobile learning (or m-learning), we present in this paper some interactive applications mainly developed for educational purposes in electronics and electromagnetics studies. In these mobile simulations, the students will be able to visualize the abstract and "invisible" physical phenomena and thus strengthen the profound understanding of the subject topic. Moreover, these kinds of apps are available for all the mobile devises using the Android operating system (Smartphones, Tablets, PDAs and Notebooks).

The probe is one of the major components building an indoor system for antenna near field measurement. This device allows to collect the distribution of the field radiated by the antenna under test (AUT), and to transform it into available voltage at its output. Thus, because of the response of the probe to other components of the field radiated by the AUT, to the influence of the geometric parameters of this one and to the problems related to the measuring surface. An unwanted error appear between the voltage and the field, and a step of post-processing is therefore necessary to correct this one. In this paper we address the problem for the correction by the technique of the deconvolution, a probe based on an Open Ended Rectangular WaveGuide (OERWG) is used to validate this approach. Thus, the spatial response of the probe is calculated in module and validated by three AUT, an open ridges rectangular waveguide, an open circular waveguide and a dipole antenna. The results obtained show that the calculated reference field and the reconstructed one are confused for the three antennas under test.

Mobile Ad hoc Network consists of some nodes that are stand randomly in operational environment. Because nodes are without any predefined infrastructure and mobility then there are susceptible to intrusions and attacks. Securing is an important field in this type of network. Intrusion Detection Systems (IDSs) may act as defensive mechanisms, since they monitor network activities in order to detect malicious actions performed by intruders, and then initiate the appropriate countermeasures. IDS for MANETs have attracted much attention recently and thus, there are many publications that propose new IDS solutions or improvements to the existing. In this paper, we propose a new IDS architecture for MANETs, this architecture is a combination model hierarchical based on clusters and cooperation model based on a multi-agent system (SMA). In this paper, we are used AUML language to describe the operation of different agents of our architecture.

The personal radiofrequency dosimeters are increasingly used for the workers exposure estimation to the electromagnetic radiations in terms of reference level of the fields. The presence of the human body at the vicinity of dosimeter compromises its measurement accuracy. In this paper, the study of interaction between personal radiofrequency dosimeter and human body is presented. First, we deal with the error introduced by the presence of the body and an approach to reduce this impact by adding elements in the dosimeter structure. Indeed, by introducing a metal ground plane and optimizing the height of antenna-ground plane, we can estimate at 10 % close the level of incidental field, that is to say a considerable reduction impact of the body on the dosimeter. We also study the stability of the intrinsic characteristics of the dosimeter (isotropy and front to back ratio). Different simulations were performed in the GSM 900 band with the finite integration technique. In the context of the design of worn-body radiofrequency dosimeters it’s very useful to master these interaction results.

In this paper, we present a new model using a Fourdimensional (4D) Element-Oriented physical concepts based on a topological approach in electromagnetism. Its general finite formulation on dual staggered grids reveals a flexible Finite-Difference Time-Domain (FDTD) method with reasonable local approximating functions. This flexible FDTD method is developed without recourse to the traditional Taylor based forms of the individual differential operators. This new formulation generalizes both the standard FDTD (S-FDTD) and the nonstandard FDTD (NS-FDTD) methods. Moreover, it can be used to generate new numerical methods. As proof, we deduce a new nonstandard scheme more accurate than the S-FDTD and the known nonstandard NS-FDTD methods. Through some numerical examples, we validate this proposal, and we show the power and the advantage of this Element-Oriented Model.

We present in this paper the calibration of a correction law to overcome the electric field (e-field) measurement errors due to the presence of the dosimeter in the vicinity of the human body. The Correction law proposes to use only two measuring points close to the body. These measurements are made at regularly goshawks separate points of the body, either in the chest, abdomen or waist. The goal is to propose a useful distributed worn-body dosimeter who can apply a correction law to these separate values compared to the maximum value known beforehand. This correction law is currently derived to simulation for GSM, DCS and UMTS downlink Bands and shortly performed by measurements. Assessing the real EMF exposure value in real-time is the key question for sanitary authorities as well as for industry (Manufacturer and Operator).

In this work, we present a new technique based on the deconvolution method for the probe correction for antenna near field measurements. In fact, because of the response of the probe to other components of the field radiated by the Antenna Under Test (AUT), to the influence of the geometric parameters of this one and to the problems related to the measuring surface. An unwanted error appear between the voltage recovered by the probe from AUT and the real field radiated by this one, and a step of post-processing is therefore necessary to correct this one. A probes based on an Open Ended Rectangular WaveGuide (OERWG) and the half-wave dipole are used in this study to validate this approach. Thus, the spatial response of the probe is calculated and validated by tests in front of real antennas. The results obtained show that the calculated reference field and the reconstructed one are confused for the three antennas under test.

The personal radiofrequency dosimeters are increasingly used for the workers exposure estimation to the electromagnetic radiations in terms of reference level of the fields. The presence of the human body at the vicinity of dosimeter compromising its measurement accuracy. In this paper, the study of interaction between personal radiofrequency dosimeter and human body is presented. Firstly, we treat the error introduced by the presence of the body and an approach to reducing this impact by adding elements in the dosimeter structure. Indeed, by introducing a metal ground plane and optimizing the height of antenna-ground plane, we can estimate at 10% close the level of incidental field, that is to say a considerable reduction impact of the body on the dosimeter. We also study the stability of the intrinsic characteristics of dosimeter (isotropy and front to back ratio). Different simulations were performed in the GSM 900 band with the finite integration technique. In the context of the design of worn-body radiofrequency dosimeter it's very useful to master these interaction results.

The probe is one of the major components building an indoor system for antenna near field measurement. In this paper, we present a geometric characterization of the Open Ended Rectangular waveguide and the pyramidal horn probes, used to measure the tangential component of the electric field. The results obtained show that the field and the voltage are proportional to the dimensions of the probes. They increase with the parameter h and they pass through a maximum for the parameters Psi and Pci.

Mobile Ad Hoc Networks (MANETs) are susceptible to a variety of attacks that threaten their operation and the provided services. Intrusion Detection Systems (IDSs) may act as defensive mechanisms, since they monitor network activities in order to detect malicious actions performed by intruders, and then initiate the appropriate countermeasures. IDS for MANETs have attracted much attention recently and thus, there are many publications that propose new IDS solutions or improvements to the existing. In this paper, we study the different existing IDS architectures for MANETs. We briefly present for each architecture, after an analysis, the strengths and weaknesses, the methods/techniques that have been proposed to improve the performances and the provided security services. Then, we propose a new IDS architecture for MANETs, this architecture is a combination model hierarchical based on clusters and cooperation model based on a multi-agent system (SMA). In this architecture, agents use a knowledge related to a global security ontology, it can be used to infer new detection rules.

Mobile Ad Hoc Networks (MANETs) are susceptible to a variety of attacks that threaten their operation and the provided services. Intrusion Detection Systems (IDSs) may act as defensive mechanisms, since they monitor network activities in order to detect malicious actions performed by intruders, and then initiate the appropriate countermeasures. IDS for MANETs have attracted much attention recently and thus, there are many publications that propose new IDS solutions or improvements to the existing. In this paper, we study the different architectures existing the IDS for MANETs. We briefly present for each architecture, after an analysis, the strengths and weaknesses, the methods/techniques that have been proposed to improve the performances and the provided security services. Then, we propose a new IDS architecture for MANET, this architecture is a combination of model hierarchical based on clusters and cooperation model based on a multi-agent system (SMA). In this architecture, agents use a knowledge base related to a global security ontology, it can be used to infer new detection rules.

With the flourish of online education and distance learning, it's become very important to make the evaluation in e-learning scientifically and objectively. This paper presents an intelligent fuzzy evaluation system based on our innovative evaluation method where management rules made by the experts are used to help, optimize and decide. On this basis, we develop an evaluation method and algorithm based on the fuzzy logic concepts and new information technologies. Thus, intelligent applications are possible if one wish to automate the management and decision while making an alarm system based on relevant indicators. Finally, we come up with an “expert system” that can provide some solutions to the problems of measurement theory. In addition, we present a concrete example to compare this method with the traditional one then draw conclusions on the effectiveness of this method.

Vision plays an important role in improving comprehension and perception of electromagnetic fields. One reason electromagnetic fields is considered by students to be a difficult course is because electromagnetic fields, being vector functions of space and time, unlike mechanics, which deals with concrete objects, are conceptually abstract and hard to visualize. Invisibility is a considerable obstacle on the way to understanding physical phenomena. To overcome this obstacle, we present in this paper some interactive simulations mainly developed for educational purposes in electromagnetics in order to facilitate the understanding of field theory and vector analysis. This interactive simulations can be used as a virtual laboratory where students can explore the solutions on their own efforts and in every detail, hence, deepening their understanding of the subject matter.

MANETs are a collection of mobile nodes that dynamically form a temporary network and are capable of communicating with each other without the use of a network infrastructure or any centralized administration. Due to the flexibility provided by their dynamic infrastructure MANETs are vulnerable to many types of security attacks. Furthermore, many conventional security solutions have been developed. However, these proposals suffer from the problems of tests and evaluations. Among these solutions the intrusion detection systems (IDS). To improve the quality of protection of MANETs provided by intrusion detection systems (IDS), we provide assessment of detection and test procedures more effective. In this paper, we make a thorough analysis of existing attacks. For this we propose a new system to classify attacks based on attributes that appear to be the best classification criteria to generate test-cases. We also apply the classification tree method (CTM) to select test-cases to attack. Finally, we use the CTE (Classification Tree Editor) tool to generate and select test-cases.

In this work we present a virtual laboratory for studying the wave propagation proprieties. This virtual lab is used to study the propagation of electromagnetic waves in most environments, in readable and progressive manner. It allows students to apply many equations views in the course. The software uses the finite-difference time-domain (FDTD) that has been successfully applied in many engineering fields. In addition, an easy-to-use MATLAB GUI handles all the parameters of the FDTD simulation and computes theoretical values of characteristics parameters of the wave propagation in different mediums. The software allows understanding the phenomena of electromagnetic wave propagation step by step; starting with the case of one dimension to three dimensions, and finally, it allows approaching particular cases like the metamaterials and plasma. Java programming language is used for programming numerical calculations, creating visualization suitable for simulations and offers the possibility to run simulation remotely.

International audience; The probe correction technique applied to reactive near-field characterization is based on a deconvolution process. However, the classical deconvolution based on an inverse Fourier transform has a restrictive limitation. It is based on the use of noiseless measurement data. Consequently, measurement noise makes the result obtained by the classical deconvolution based technique inefficient and requires an extremely low noise measurement facility. In this paper, a method to improve the probe correction stability when using corrupted measurement data is presented. The proposed constrained least squares filtering algorithm (CLSF) uses an inverse filtering approach that takes into account the statistical characteristics of the measurement noise. Computations data with electromagnetic software of two different structures validate this method and illustrate its reliability.

The aim of the work presented here is to develop an accurate and cheap electromagnetic simulation software that provides a virtual laboratory for studying the wave propagation proprieties. The numerical method used is the finite-difference time-domain (FDTD) that has been successfully applied in many engineering fields. In addition, an easy-to-use MATLAB GUI handles all the parameters of the FDTD simulation and computes theoretical values of characteristics parameters of the wave propagation in different mediums. The software allows understanding the phenomena of electromagnetic wave propagation in a progressive manner starting with the case of one dimension to three dimensions, and finally it allows approaching particular cases like the metamaterials.

In this paper, we present an interactive simulation of a Metal-Oxide-Semiconductor structure, based on a qualitative approach. The code is written in ActionScript / Flash to enjoy all the benefits of this technology in the multimedia field. In addition, our simulation combines theoretical and practical concepts on the same graphical interface: it shows the impact of physical and electrical parameters on the behavior of a MOS structure or a transistor TMOS. Moreover, it provides the physical reasons of the parameters influence that can serve to evaluate the relevance of approximations commonly used. This simulation is applied in engineering education.