This study critically explores the perceptions of students on the implementation of the English as a medium of instruction (EMI) policy at a public higher education institution in Oman and its effect on the quality of their learning experiences and academic performance. Although the Gulf has recently witnessed an increase in research on EMI, such research is rather scarce in Oman in particular from a critical approach. Through the focus on students’ perspectives, the study gives a voice to otherwise voiceless students whose insights have been largely ignored by language policy planners. For the study, a critical exploratory methodology was adopted where in-depth qualitative data were collected through a two-phase sequential mixed methods approach that consisted of a questionnaire distributed among 328 students studying in seven different faculties, 14 classroom observations and 14 students’ interviews. The findings suggest that the majority of participants either supported or accepted the EMI policy for pragmatic reasons based on the utilitarian function of English as a lingua franca in Oman and its requirement for future jobs. However, the participants acknowledged that they faced great difficulties in their study which was mainly caused by their insufficient language competence. It was also acknowledged that Arabic as a medium of instruction (AMI) would lead to a more comprehensive understanding of the subject matter and would most probably lead to better academic performance. Few participants found that the endorsement of EMI negatively influenced their ability to use Modern Standard Arabic (MSA) and marginalised the role of Arabic in their society. Overall, the implementation of EMI had a disempowering effect on students with low English language proficiency and had a negative psychological impact on them. Based on the findings, the EMI policy has been contested since it does not provide students with equal opportunities to study at tertiary level. In addition, the quality of education has been compromised in response to assumed market forces. Also, a strict EMI policy does not allow students to enhance their Arabic competence which is relevant for future employment. The pedagogic competence of teachers has also been questioned and gaps in the support system for students with language deficiencies have been identified. The study makes several recommendations that are expected to improve the learning conditions of students studying at tertiary level through EMI. The recommendations include the enhancement of English language teaching (ELT) in schools to better prepare students for their academic study in English. In addition, AMI courses should be offered in all faculties due to its support in gaining profound comprehension of the subject matter and its relevance for students’ future jobs. Teachers should be given the opportunity to develop their pedagogic competence that would allow them to use a student-centred approach in teaching through EMI or AMI. Finally, the college should increase students’ support in their study especially in EMI through creating support centres where they could resort to in case they face any difficulties in their study.

This thesis explores students’ views concerning the current English as medium of instruction (EMI) policy at Kuwait’s two public higher education institutions, Kuwait University (KU) and the Public Authority for Applied Education and Training (PAAET). In line with the exploratory nature of this study, an interpretivist and social constructivist epistemological stance was implemented to elicit and analyse students’ views and gain their insights on the current situation. The study employed a sequential mixed method design using quantitative (questionnaire) and qualitative (focus groups, semi-structured interviews and semi-structured observations) methods to present a holistic picture. The number of the participants were 12 for the focus groups, 100 for the questionnaire, 11 for the in-depth interviews and 10 teaching sessions were observed. Descriptive statistics were calculated for the quantitative strand data and thematic analysis was used for the qualitative data. The study revealed that although most participants preferred to learn through English, the current EMI policy raised many concerns. These related to students having to endure an ‘extra burden’ and the additional effort needed to study a subject being taught in a language that was not their mother tongue. The students expressed the view that this resulted in them being unable to gain a deep knowledge of the subject and not attain high grades which then affected their career prospects. These issues arose due to the students not being sufficiently competent in the use of English at the high level expected for degree level work. Students also expressed concerns relating to EMI policy effects on Arab identity and on the use of Arabic as a language of science and academia. Students would prefer a policy that promoted the use of both Arabic and English in their courses which would enable them to benefit from developing their understanding of both languages. The thesis concludes by presenting a recommendation to modify the medium of instruction policy such that it incorporates both English and Arabic. These recommendations have implications for policymakers, teachers and students.

Elektromagnetiska störningar kan orsaka stora och allvarliga problem både i land och ombord på fartyg. Störningar som kommer in i kontrollerade utrymmen via kablage kan förhindras genom speciellt framtagna kabelgenomföringar. Dock gäller att dessa är installerade korrekt och syftet med detta arbete är att ta fram en principmodell för ett portabelt kontrollinstrument för kontroll av elektromagnetisk kompatibilitet (EMC).   Genom att ta delar ur flertalet internationella standarder inom EMC-området togs en principmodell för kontrollinstrumentet fram. Genom simulering kunde delar av principen fastställas och sedan utfördes praktiska prover där testuppsättningen hade sitt ursprung i en vedertagen och beprövad uppsättning.   Proverna visade på att principmodellen fungerar. Dock uppnådde inte modellens mätenhet samma mätnoggranhet som referensinstrumentet och dämpningar i de framtagna kretsarna skiljde sig från de framräknade värdena.

The applications of wireless sensor networks, WSN, are getting popular in the different areas reaching from daily usage to industrial usage. The performance evaluation of WSN deployed in industrial and high-voltage areas is receiving a great attention and becoming an interesting area of research. This thesis addresses the performance issues of WSN in high-voltage and harsh industrial environments. This study has been carried out at the facilities of High Voltage Test Lab of ABB. Typically, wireless sensor network contains wireless field devices (nodes) connected to a base station via a central gateway. The gate way centralizes information gathered and processed by the nodes. The nodes can communicate with each other and with the gateway via radio wave. The quality and usability of the data sent by WSN can be degraded due to the packet loss and delay. In the presence of high-voltage, the electromagnetic interference, EMI, can affect the performance of WSN. In this study the performance of WSN is evaluated in terms of packet loss and delay. We also focus on the effect of EMI on hardware devices as well as on signal transmission. EMI was expected at wide frequency band due to harsh industrial and high voltage environments. It was expected that EMIs could increase a bit error rate and/or packet loss. The EMI can also change the sensitivity of the nodes. For the performance evaluation of WSN network throughput, latency, path stability, data reliability and average value of the received signal strength indicator, RSSI, are used and measured. The results show that the electromagnetic frequencies of harsh industrial and high voltage environments affect the wireless sensor network performance. / 0046700375216

The aim of this semestral project was to propose the measuring system for measuring three-phase EMI filters in symmetrical, asymmetrical and non-symmetrical mode according to information from supplier of the filters. The major part of this project was focused on measuring the frequency dependence of the insertion loss of three-phase EMI filters in impedance systems 50?/50?, 0,1?/100 ? and 100?/0,1?. It was determined that results approximately agree with specifications in datasheets.

L'augmentation du nombre de fonctions électriques disponibles dans les systèmes embarqués amène de nouvelles contraintes d'encombrement et de masse de leurs alimentations. Pour adresser ces problèmes, la miniaturisation et l'intégration des convertisseurs statiques sont donc des thématiques importantes de recherche qui aboutissent à de nombreuses évolutions technologiques et structurelles dont l'apparition de convertisseurs statiques à fréquence de fonctionnement élevée permettant la réduction des éléments passifs du convertisseurs.Ces avancées s'accompagnent cependant d'une augmentation des niveaux de perturbations électromagnétiques générés par le système. Afin de les diminuer, l'insertion de filtres CEM dans le système est nécessaire. Leurs performances sont fortement liées au contrôle de leurs éléments parasites. Les modèles développés jusqu'à présent concernent pour la plupart les effets conduits et l'évaluation de l'impact des phénomènes rayonnés est souvent ignoré ou au mieux basé sur des modèles simplistes. Un des objectifs de cette thèse est donc d'apporter un degré de complexification plus élevé des modèles de rayonnement des composants magnétiques utilisés dans les filtres CEM, tant par une approche par modélisation numérique que par la mise en oeuvre d'un modèle analytique.Dans un premier temps, une étude poussée du rayonnement magnétique de composants simples, les inductances toriques de mode différentiel, a été réalisée. Cette étude a débouché sur la mise en évidence des paramètres critiques déterminant la topologie du champ magnétique rayonné dans l'environnement proche du composant. Le résultat majeur de cette étude est l'importance de la répartition du bobinage autour du circuit magnétique sur le champ magnétique rayonné. De nouveaux modèles ont été proposés pour permettre la prédiction des champs proches rayonnés pour une gamme de fréquence inférieure à la résonance propre du composant.Par la suite, un modèle analytique fin du rayonnement magnétique des inductances de mode commun a été proposé. Ce modèle permet de déterminer \emph{a priori} le rayonnement magnétique proche du composant. Les études menées par la suite ont permis de relier les effets observés en rayonné au phénomènes conduits qui apparaissent dans ces composants notamment pour expliquer certains effets de transfert de mode (commun/différentiel).Dans une dernière partie, une étude de ces composants en susceptibilité électromagnétique (EM) a été menée. Elle a permis de rendre compte de l'influence d'une onde incidente de champ magnétique sur les composants étudiés et de valider les modèles proposés via une approche basée sur la réciprocité EM: la direction privilégiée de rayonnement est aussi celle de couplage facile pour un champ magnétique externe. / The number of electronic devices in embedded systems is constantly increasing and their contribution to volume and weight is a major concern. In order to solve these issues, a large research effort is devoted to volume reduction and power converters' integration. This lead to constant technological evolution including the appearance of high frequency power electronic converters allowing the reduction of the volume of passive components.However, due to the increase of operating frequencies and the minimization of inter-components distances, the electromagnetic radiations generated by these systems become more important. In order to decrease this interference, EMI filters are often necessary. Their performances are often related to the value of parasitic elements in the filter which must therefore be controlled. Nonetheless most of the existing models focus on conducted electromagnetic interference (EMI) and the impact of radiated phenomena is often ignored or greatly simplified. This work will therefore focus on developing highly accurate radiation models for magnetic components commonly used in EMI filters using both numeric and analytic tools.First, the magnetic fields radiated by differential mode (MD) toroidal coils, which belong to the basic magnetic components, will be thoroughly studied. This study highlighted the critical parameters determining the near-field topology. The main result is the discovery of the impact of the winding's layout around the magnetic core on the radiated magnetic field. New models have been developed in order to predict the radiated near field.Then, an accurate analytic model of the the magnetic radiation of common-mode (CM) chokes has been developed. It allows the prediction of the magnetic near-field. The application of the model lead to the correlation between radiated phenomena and conducted effects existing in these components. The importance of the winding on CM to DM mode coupling has therefore been highlighted.Finally, the electromagnetic (EM) susceptibility of these components has been studied. This work describes the influence of an external magnetic field on the components and validates the radiation models developed using the principle of EM reciprocity. It has been shown that the easy directions are the same for both the radiated and the coupled phenomena.

A worldwide awareness of the environment is accelerating fuel cell vehicle development. With respect to power electronics, special requirement is on the development of high efficiency, high voltage ratio bi-directional DC/DC converter for fuel cell energy system management. In this paper, two bi-directional DC/DC converters, which are developed for Ford Motor Company’s fuel cell vehicle, are compared from different aspects. Comparison is concentrated on the circuit topology and EMI performance. Emphasis is placed on soft-switch, hard-switch, synchronized rectification, auxiliary start-up winding and their effect on EMI performance in this kind of isolated bi-directional converter. Comparison includes circuits analysis and test result. The EMI test setup is described. EMI measurements are given and explained. EMI solutions for bi-directional DC/DC converter are discussed. An EMI filter is designed and final test result is given. / Master of Science

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Electromagnetic compatibility and compliance with relevant standards is imperative for commercial success for any type of electronic equipment. Since more and more electronics are constantly added into today’s vehicles, this is a highly significant matter in the automotive business. The primary source of electric energy in an on-road vehicle is typically a 12 or 24 volt battery; this makes voltage step down converters ubiquitous in virtually any automotive electronic system. In strive for ever more environmental friendly and energy efficient solutions a switch mode power supply is most often the given choice when it comes to the task of voltage conversion. However, the use of switch mode power supplies presents a new set of challenges when it comes to successfully comply with the electromagnetic emission standards. Knowledge and understanding about how different design parameters impact on EMC performance is key when few prototype runs and short time to market lies in focus. This text will investigate just how different layout design parameters affect the radiated emissions from a buck converter. Emphasis lies on radiated emissions in the lower frequency range up to a few MHz. Both computer simulations and practical measurements indicate the same thing; in the lower part of the frequency spectrum, when measured according to CISPR 25, radiated emissions from buck converters are dominated by voltage driven mechanisms. Along the way we will see how PCB layout alone can be responsible for differences in measured radiated emission levels of well over 20 dB.