The language of learning : Maltese teachers’ views on bilingual and multilingual primary classrooms

Recent global migration trends and an increase in worldwide human mobility are currently contributing to unparalleled challenges in the area of literacy and education within multicultural and multilingual societies (Leikin, Schwartz, & Tobin, 2012). Malta, a small island in the Mediterranean, is one country currently seeking ways in which to adapt to the realities of today’s diverse classrooms. This paper details original research into Maltese teachers’ perceptions and practices in multilingual classrooms. Following a brief overview of Malta's language history and educational system, we draw on the experiences of eight bilingual primary school teachers through in-depth, semi-structured interviews. Recent demographic changes in Malta necessitate a paradigm shift in education. With Malta’s challenges mirrored at global level, this study makes an important contribution to understanding the issues faced by educators and children, exploring pathways towards an equitable and socially just education for all

In Other Words: Maltese Primary School Teachers’ Perceptions of Cross-linguistic Practices and Flexible Language Pedagogies in Bilingual and Multilingual English Language Classes

As a result of globalisation, bilingualism and multilingualism are becoming more of a norm rather than an exception and speaking two or more languages is associated with multiple benefits. Bilingual social identities are shaped by language acquisition and socialisation, and educators construct their own teacher identities and pedagogies through their past personal, educational, and professional experiences. This study provides a basis for critical reflection and discussion amongst English language primary school Maltese teachers, to explore how their bilingual identities affect their pedagogical practices. The study probes into teacher’s perceptions on whether, why and how cross-linguistic pedagogies are beneficial within bilingual and multilingual language classroom settings. Data was collected through in-depth semi-structured interviews with nine purposely selected primary school teachers, each with over ten years teaching experience, to explore their bilingual identities and beliefs, how being bilingual may affect their pedagogical practices, and to investigate whether they believe they are using cross-linguistic practices during English lessons. The process of data collection and analysis highlighted the fact that educators’ perceived pedagogies, beliefs, and language preferences stem from their own personal, educational, and teaching experiences, and are embedded in Malta’s socio-cultural context. Maltese teachers believe that they use fluid language practices in their classrooms as a natural part of their daily communicative practices, and as a means of reaching out to all their students. However, they are uncertain about the benefits of these practices, and of how they can strategically utilise them in a structured manner. Furthermore, as a result of recent demographic shifts in Malta, teachers are raising concerns about the new challenges they are facing related to multilingualism. This study supports previous research advocating the use of fluid and hybridised language practices such as translanguaging as the way forward in meeting the super-diversity of today’s classrooms. Demographic changes on the island call for an appraisal of the pedagogical use of judiciously hybridising languages in order to provide a socially just and equitable education for all. In view of these findings, recommendations are made to policy makers, stake holders and practitioners to improve the effectiveness of initial teacher education programmes and professional practice. In conclusion, in view of the limitations of the study, recommendations are made for further research, as to contribute to the existing body of knowledge on the subject

A new coupling solution for G3-PLC employment in MV smart grids

This paper proposes a new coupling solution for transmitting narrowband multicarrier power line communication (PLC) signals over medium voltage (MV) power lines. The proposed system is based on an innovative PLC coupling principle, patented by the authors, which exploits the capacitive divider embedded in voltage detecting systems (VDS) already installed inside the MV switchboard. Thus, no dedicated couplers have to be installed and no switchboard modifications or energy interruptions are needed. This allows a significant cost reduction of MV PLC implementation. A first prototype of the proposed coupling system was presented in previous papers: it had a 15 kHz bandwidth useful to couple single carrier PSK modulated PLC signals with a center frequency from 50–200 kHz. In this paper, a new prototype is developed with a larger bandwidth, up to 164 kHz, thus allowing to couple multicarrier G3-PLC signals using orthogonal frequency division multiplexing (OFDM) digital modulation. This modulation ensures a more robust communication even in harsh power line channels. In the paper, the new coupling system design is described in detail. A new procedure is presented for tuning the coupling system parameters at first installation in a generic MV switchboard. Finally, laboratory and in-field experimental test results are reported and discussed. The coupling performances are evaluated measuring the throughput and success rate in the case of both 18 and 36 subcarriers, in one of the different tone masks standardized for the FCC-above CENELEC band (that is, from 154.6875–487.5 kHz). The experimental results show an efficient behavior of the proposed coupler allowing a two-way communication of G3-PLC OFDM signals on MV networks

A case of a rare hibernoma tumour and a brief literature review

Hibernomas refer to benign tumours of immature adipose tissue known a brown fat. They are most commonly found in areas where brown adipose tissue is still present in adulthood such as the shoulder, back, neck, best, arm and abdomen. This case study describes a 60 year old male who presented with a growing 15 mm lump in the right forearm. On examination, tenderness in the area surrounding the mass was elicited. A magnetic resonance image of the right forearm was performed which reported a large intramuscular lipomatous tumour within the brachioradialis muscle, in close relation to the neuromuscular bundle. Surgical excision was performed successfully. Histology was consistent with a diagnosis of a hibernoma tumour. The patient healed well with no evidence of infection or recurrence on follow up

Incremental heuristic approach for meter placement in radial distribution systems

The evolution of modern power distribution systems into smart grids requires the development of dedicated state estimation (SE) algorithms for real-time identification of the overall system state variables. This paper proposes a strategy to evaluate the minimum number and best position of power injection meters in radial distribution systems for SE purposes. Measurement points are identified with the aim of reducing uncertainty in branch power flow estimations. An incremental heuristic meter placement (IHMP) approach is proposed to select the locations and total number of power measurements. The meter placement procedure was implemented for a backward/forward load flow algorithm proposed by the authors, which allows the evaluation of medium-voltage power flows starting from low-voltage load measurements. This allows the reduction of the overall costs of measurement equipment and setup. The IHMP method was tested in the real 25-bus medium-voltage (MV) radial distribution network of the Island of Ustica (Mediterranean Sea). The proposed method is useful both for finding the best measurement configuration in a new distribution network and also for implementing an incremental enhancement of an existing measurement configuration, reaching a good tradeoff between instrumentation costs and measurement uncertainty

Characterization of DC series arc faults in PV systems based on current low frequency spectral analysis

This work presents an experimental study focused on the characterization of series arc faults in direct current (DC) photovoltaic (PV) systems. The aim of the study is to identify some relevant characteristics of arcing current, which can be obtained by means of low frequency spectral analysis of current signal. On field tests have been carried out on a real PV system, in accordance with some tests requirements of UL 1699B Standard for protection devices against PV DC arc faults. Arcing and non-arcing current signals are acquired and compared and the behavior of a set of indicators proposed by authors is analyzed. Different measurement equipment have been used, in order to study the impact of both measurement transducers and data acquisition systems on proposed indicators effectiveness. Presented results show that the considered indicators are suitable for detecting the arc presence even with commercial devices normally used for smart metering applications

An interface protection system based on an embedded metrology system platform

The aim of this work is to present an interface protection system (IPS) for Distributed Generators (DG) and Energy Storage Systems (ESS). The new prototype of IPS guarantees standard protection requirements, in terms of both voltage and frequency measurement accuracies and trip times. Moreover, it has the additional functionalities of implementing a communication link between the Distribution System Operator (DSO) and the DG and ESS Inverter. The new IPS is based on a smart meter platform with an integrated power line communication modem. Moreover, it has also an integrated metrology section. Experimental tests will show how this last feature allows a significant reduction of the measurement data access time allowing an improvement of trip time accuracy

A Line Impedance Calculator Based on a G3 PLC Modem Platform

Power line communication (PLC) is one of the most today used technologies for both automatic meter reading and many other smart grid applications. In this framework, a characterization of the electrical network in the PLC frequency range is needed in terms of impedance measurement and received signal level. This can allow choosing the most suitable and less noisy frequency ranges for PLC transmission. Usually, these characterization measurements are performed with dedicated instrumentation and in the absence of mains voltage. This article wants to propose an alternative solution, which allows these kinds of measurements to be performed using electronic boards currently used as on-field applications, such as smart meters. To this aim, an innovative measurement tool is proposed, which does not need a specific characterization signal to be injected because it uses the preamble of a generic PLC transmission. Moreover, the impedance calculation is performed using an FFT analysis, which does not require high computational capabilities. These features allowed the proposed tool to be implemented using a G3-PLC transceiver, embedded in many commercial smart meters, and low-cost additional hardware. This article shows how the proposed system correctly measures the PLC impedance on CENELEC A, B, and FCC frequency ranges

Li-ion battery modeling and state of charge estimation method including the hysteresis effect

In this paper, a new approach to modeling the hysteresis phenomenon of the open circuit voltage (OCV) of lithium-ion batteries and estimating the battery state of charge (SoC) is presented. A characterization procedure is proposed to identify the battery model parameters, in particular, those related to the hysteresis phenomenon and the transition between charging and discharging conditions. A linearization method is used to obtain a suitable trade-off between the model accuracy and a low computational cost, in order to allow the implementation of SoC estimation on common hardware platforms. The proposed characterization procedure and the model effectiveness for SoC estimation are experimentally verified using a real grid-connected storage system. A mixed algorithm is adopted for SoC estimation, which takes into account both the traditional Coulomb counting method and the developed model. The experimental comparison with the traditional approach and the obtained results show the feasibility of the proposed approach for accurate SoC estimation, even in the presence of low-accuracy measurement transducers

CZT-Based Harmonic Analysis in Smart Grid Using Low-Cost Electronic Measurement Boards

This paper validates the use of a harmonic analysis algorithm on a microcontroller to perform measurements of non-stationary signals in the context of smart grids. The increasing presence of electronic devices such as inverters of distributed generators (DG), power converters of charging stations for electric vehicles, etc. can drain non-stationary currents during their operation. A classical fast Fourier transform (FFT) algorithm may not have sufficient spectral resolution for the evaluation of harmonics and inter-harmonics. Thus, in this paper, the implementation of a chirp-Z transform (CZT) algorithm is suggested, which has a spectral resolution independent from the observation window. The CZT is implemented on a low-cost commercial microcontroller, and the absolute error is evaluated with respect to the same algorithm implemented in the LabVIEW environment. The results of the tests show that the CZT implementation on a low-cost microcontroller allows for accurate measurement results, demonstrating the feasibility of reliable harmonic analysis measurements even in non-stationary conditions on smart grids