Kaksikielinen pedagogiikka ja kielelliset oikeudet viittovan oppilaan opetuksessa

Tiivistelmä. Suomen lakeja, säädöksiä ja kielipoliittisia lausuntoja tarkasteltaessa näyttäisi, että viittomakielisten oppilaiden kielelliset oikeudet on hyvin turvattu. Perusopetuksen opetussuunnitelmaan sekä lakiteksteihin on kirjattu, että opetuksen on oltava viittomakielistä tarvittaessa. Viittomakielestä ja sen eri variaatioista eivät hyödy vain kuurot, vaan myös huonokuuloiset ja kuuroutuneet. Viittomakieli ja sen variaatiot ovat kuitenkin monelle viittovia oppilaita opettavalle vieraita kielenmuotoja, jotka tulee opiskella erikseen. Viittovat oppilaat ovat myös usein kaksikielisiä, jolloin opetuskielten on oltava tätä tukevaa. Opettajilta vaaditaankin erilaisia valmiuksia opettaa viittoen. Tämän pro gradu -tutkielman tavoitteena onkin selvittää, millaisia valmiuksia erityisopettajilla on opettaa viittoen sekä millaisia pedagogisia ja kielellisiä ratkaisuja viittovissa luokissa tehdään. Tutkielman keskiössä ovat kielelliset oikeudet ja niiden toteutuminen. Tutkielman teoreettinen viitekehys tarkastelee viittovan henkilön kaksikielisyyttä sekä äidinkielten eroavaisuuksia. Lisäksi tarkastellaan tasa-arvoisten kielellisten oikeuksien laki- ja säädösperusteita sekä viittovan oppilaan opetuksessa huomioitavia asioita. Tutkielma on laadullinen tutkimus, jonka metodologinen lähestymistapa on fenomenografia ja metodina on käytetty haastatteluja. Tutkimusaineisto on kerätty strukturoiduilla teemahaastatteluilla, joihin on osallistunut yhdeksän opettajaa eri puolilta Suomea. Aineiston analyysissä on hyödynnetty fenomenografista analyysimallia. Tutkimustulokset osoittavat, että kielelliset oikeudet ovat kouluissa tiedostettuja, mutta käytännön tasolla toteutus voi olla haastavaa. Tähän vaikuttavat oleellisimmin opettajan kielitaito sekä oppilasaineksen muuttuminen (kuuroja viittomakielisiä oppilaita ei ole enää useita). Muuttunut oppilasaines vaikuttaa lisäksi viittovan luokan kielivalintoihin. Tuloksissa kiteytettiin, että viittovan oppilaan opetus tulee olla kaksikielistä, kieli- ja kulttuuri-identiteetti huomioivaa, visuaalista sekä oppilaan kieltä arvostavaa. Opettajan valmiuteen opettaa viittoen vaikuttavat koulutustausta, jolla opettaja on voinut viittomistaitoa hankkia. Haastatellut opettajat kaipaavat erityispedagogiikan koulutukseen viittomiskursseja, mutta tärkeämmässä roolissa nähdään työnantajat, joiden kouluissa opettajille tulisi järjestää eritasoisia viittomakursseja. Johtopäätöksenä esitetään, että viittovan oppilaan opetuksessa on otettava monipuolisesti huomioon kolmen tekijän kombinaatio: kaksikielinen pedagogiikka, kielelliset oikeudet sekä viittova oppimisympäristö. Vaikka viittomakieli ei olisi viittovan oppilaan kommunikaatio, voi viittomat olla erittäin tärkeitä kommunikaation edistäjiä. Tutkielmaa voi soveltaa viittovien oppilaiden opetuksen toteuttamisessa sekä yhteiskunnallisessa keskustelussa kielellisesti tasa-arvoisen opetuksen järjestämisessä.Bilingual pedagogic and linguistic rights in sign education. Abstract. Linguistic rights of sign language pupils are well assured by the Finnish laws, regulations and linguistic verdicts. Sign language with its different variations are not benefitting only deafs but as well hard of hearings. Curriculum of basic education and the Finnish laws include the statement that teaching must be operated using sign language when needed. However, sign language with its variations are foreign language forms for the teachers and they are to be studied separately. Pupils using signs are often bilingual thus the teaching pedagogic must support this. Therefore teachers must have different kind of readiness to sign education. The goal of this Master’s Thesis is to clarify which kind of readiness the special education teachers have for sign education as well as what kind of pedagogical and linguistic decisions are made in classrooms using signs. The essence of this thesis is linguistic rights and their implementation. Theoretic framefork of this thesis examines bilinguality of person using signs and the differencies of mother tongues. Additionally, laws and regulations for equal linguistic rights and essential matters to be taken into account in teaching are considered. This thesis is a qualitative research using phenomenography as a methological approach. Interviews are used as a method. The reseach data has been collected by structured theme interviews with nine teachers accross Finland. The analysis is based on phenomenographic model. According to the results linguistic rights are well known in schools but practical implementation may be challenging. This is mostly affected by language proficiency of the teacher and the change in pupil base (the number of deaf sign language users is decreasing).The changed pupil base affects also on language choices in the classroom. The teaching of the pupil using signs must be bilingual and visual. The language and cultural identities must be considered and pupil’s language must be appreciated. The education and training courses for signing skills have a major influense for teacher’s readiness for sign education. There is a need for signing courses in special education training but it is more important to arrange signing courses for teachers in schools. The conclusion of this Master’s Thesis is that the teaching of the pupil using signs must consider the combination of three factors: Bilingual pedagogic, linguistic rights, and signing study environment. Although sign language is not the communication of the pupil signs can have an important role as a contributor of communication. This study can be applied in realisation of sign education and in social discussion regarding to arrangement of equal linguistic education

A machine learning approach based on generative topographic mapping for disruption prevention and avoidance at JET

The need for predictive capabilities greater than 95% with very limited false alarms are demanding requirements for reliable disruption prediction systems in tokamaks such as JET or, in the near future, ITER. The prediction of an upcoming disruption must be provided sufficiently in advance in order to apply effective disruption avoidance or mitigation actions to prevent the machine from being damaged. In this paper, following the typical machine learning workflow, a generative topographic mapping (GTM) of the operational space of JET has been built using a set of disrupted and regularly terminated discharges. In order to build the predictive model, a suitable set of dimensionless, machine-independent, physics-based features have been synthesized, which make use of 1D plasma profile information, rather than simple zero-D time series. The use of such predicting features, together with the power of the GTM in fitting the model to the data, obtains, in an unsupervised way, a 2D map of the multi-dimensional parameter space of JET, where it is possible to identify a boundary separating the region free from disruption from the disruption region. In addition to helping in operational boundaries studies, the GTM map can also be used for disruption prediction exploiting the potential of the developed GTM toolbox to monitor the discharge dynamics. Following the trajectory of a discharge on the map throughout the different regions, an alarm is triggered depending on the disruption risk of these regions. The proposed approach to predict disruptions has been evaluated on a training and an independent test set and achieves very good performance with only one tardive detection and a limited number of false detections. The warning times are suitable for avoidance purposes and, more important, the detections are consistent with physical causes and mechanisms that destabilize the plasma leading to disruptions.Peer reviewe

RF sheath modeling of experimentally observed plasma surface interactions with the JET ITER-Like Antenna

Waves in the Ion Cyclotron Range of Frequencies (ICRF) enhance local Plasma-Surface Interactions (PSI) near the wave launchers and magnetically-connected objects via Radio-Frequency (RF) sheath rectification. ITER will use 20MW of ICRF power over long pulses, questioning the long-term impact of RF-enhanced localized erosion on the lifetime of its Beryllium (Be) wall. Recent dedicated ICRF-heated L-mode discharges documented this process on JET for different types of ICRF antennas. Using visible spectroscopy in JET ICRF-heated L-mode discharges, poloidally-localized regions of enhanced (by similar to 2-4x) Be I and Be II light emission were observed on two outboard limiters magnetically connected to the bottom of the active ITER-Like Antenna (ILA). The observed RF-PSI induced by the ILA was qualitatively comparable to that induced by the JET standard, type-A2 antennas, for similar strap toroidal phasing and connection geometries. The Be II line emission was found more intense when powering the bottom half of the ILA rather than its top half. Conversely, more pronounced SOL density modifications were observed with only top array operation, on field lines connected to the top half of the ILA. So far the near-field modeling of the ILA with antenna code TOPICA (Torino Polytechnic Ion Cyclotron Antenna), using curved antenna model, was partially able to reproduce qualitatively the observed phenomena. A quantitative discrepancy persisted between the observed Be source amplification and the calculated, corresponding increases in E-// field at the magnetically connected locations to the ILA when changing from only top to only bottom half antenna operation. This paper revisits these current drive phased and half-ILA powered cases using for the new simulations flat model of the ILA and more realistic antenna feeding to calculate the E-// field maps with TOPICA code. Further, the Self-consistent Sheaths and Waves for Ion Cyclotron Heating Slow Wave (SSWICH-SW) code, which couples slow wave evanescence with DC Scrape-Off Layer (SOL) biasing, is used to estimate the poloidal distribution of rectified RF-sheath Direct Current (DC) potential V-DC in the private SOL between the ILA poloidal limiters. The approach so far was limited to correlating the observed, enhanced emission regions at the remote limiters to the antenna near-electric fields, as calculated by TOPICA. The present approach includes also a model for the rectification of these near-fields in the private SOL of the ILA. With the improved approach, when comparing only top and only bottom half antenna feeding, we obtained good qualitative correlation between all experimental measurements and the calculated local variations in the E-// field and V-DC potential.Peer reviewe

Current Research into Applications of Tomography for Fusion Diagnostics

Retrieving spatial distribution of plasma emissivity from line integrated measurements on tokamaks presents a challenging task due to ill-posedness of the tomography problem and limited number of the lines of sight. Modern methods of plasma tomography therefore implement a-priori information as well as constraints, in particular some form of penalisation of complexity. In this contribution, the current tomography methods under development (Tikhonov regularisation, Bayesian methods and neural networks) are briefly explained taking into account their potential for integration into the fusion reactor diagnostics. In particular, current development of the Minimum Fisher Regularisation method is exemplified with respect to real-time reconstruction capability, combination with spectral unfolding and other prospective tasks.Peer reviewe

Modelling of tungsten erosion and deposition in the divertor of JET-ILW in comparison to experimental findings

The erosion, transport and deposition of tungsten in the outer divertor of JET-ILW has been studied for an H-Mode discharge with low frequency ELMs. For this specific case with an inter-ELM electron temperature at the strike point of about 20 eV, tungsten sputtering between ELMs is almost exclusively due to beryllium impurity and self-sputtering. However, during ELMs tungsten sputtering due to deuterium becomes important and even dominates. The amount of simulated local deposition of tungsten relative to the amount of sputtered tungsten in between ELMs is very high and reaches values of 99% for an electron density of 5E13 cm(-3) at the strike point and electron temperatures between 10 and 30 eV. Smaller deposition values are simulated with reduced electron density. The direction of the B-field significantly influences the local deposition and leads to a reduction if the E x B drift directs towards the scrape-off-layer. Also, the thermal force can reduce the tungsten deposition, however, an ion temperature gradient of about 0.1 eV/mm or larger is needed for a significant effect. The tungsten deposition simulated during ELMs reaches values of about 98% assuming ELM parameters according to free-streaming model. The measured WI emission profiles in between and within ELMs have been reproduced by the simulation. The contribution to the overall net tungsten erosion during ELMs is about 5 times larger than the one in between ELMs for the studied case. However, this is due to the rather low electron temperature in between ELMs, which leads to deuterium impact energies below the sputtering threshold for tungsten.Peer reviewe

Investigation of deuterium trapping and release in the JET divertor during the third ILW campaign using TDS

Selected set of samples from JET ITER-Like Wall (JET-ILW) divertor tiles exposed in 2015-2016 has been analysed using Thermal Desorption Spectrometry (TDS). The deuterium (D) amounts obtained with TDS were compared with Nuclear Reaction Analysis (NRA). The highest amount of D was found on the top part of inner divertor which has regions with the thickest deposited layers as for divertor tiles removed in 2014. This area resides deep in the scrape-off layer and plasma configurations for the second (ILW-2, 2013-2014) and the third (ILW-3, 2015-2016) JET-ILW campaigns were similar. Agreement between TDS and NRA is good on the apron of Tile 1 and on the upper vertical region whereas on the lower vertical region of Tile 1 the NRA results are clearly smaller than the TDS results. Inner divertor Tile 3 has somewhat less D than Tiles 0 and 1, and the D amount decreases towards the lower part of the tile. The D retention at the divertor inner and outer corner regions is not symmetric as there is more D retention poloidally at the inner than at the outer divertor corner. In most cases the TDS spectra for the ILW-3 samples are different from the corresponding ILW-2 spectra because HD and D-2 release occurs at higher temperatures than from the ILW-2 samples indicating that the low energy traps have been emptied during the plasma operations and that D is either in the energetically deep traps or located deeper in the sample.Peer reviewe

Comparison of the structure of the plasma-facing surface and tritium accumulation in beryllium tiles from JET ILW campaigns 2011-2012 and 2013-2014

In this study, beryllium tiles from Joint European Torus (JET) vacuum vessel wall were analysed and compared regarding their position in the vacuum vessel and differences in the exploitation conditions during two campaigns of ITER-Like-Wall (ILW) in 2011-2012 (ILW1) and 2013-2014 (ILW2) Tritium content in beryllium samples were assessed. Two methods were used to measure tritium content in the samples - dissolution under controlled conditions and tritium thermal desorption. Prior to desorption and dissolution experiments, scanning electron microscopy and energy dispersive x-ray spectroscopy were used to study structure and chemical composition of plasma-facing-surfaces of the beryllium samples. Experimental results revealed that tritium content in the samples is in range of 2.10(11)-2.10(13) tritium atoms per square centimetre of the surface area with its highest content in the samples from the outer wall of the vacuum vessel (up to 1.9.10(13) atoms/cm(2) in ILW1 campaign and 2.4.10(13) atoms/cm(2) in ILW2). The lowest content of tritium was found in the upper part of the vacuum vessel (2.0.10(12) atoms/cm(2) and 2.0.10(11) atoms/cm(2) in ILW1 and ILW2, respectively). Results obtained from scanning electron microscopy has shown that surface morphology is different within single tile, however if to compare two campaigns main tendencies remains similar.Peer reviewe

Dynamic modelling of local fuel inventory and desorption in the whole tokamak vacuum vessel for auto-consistent plasma-wall interaction simulations

An extension of the SolEdge2D-EIRENE code package, named D-WEE, has been developed to add the dynamics of thermal desorption of hydrogen isotopes from the surface of plasma facing materials. To achieve this purpose, D-WEE models hydrogen isotopes implantation, transport and retention in those materials. Before launching autoconsistent simulation (with feedback of D-WEE on SolEdge2D-EIRENE), D-WEE has to be initialised to ensure a realistic wall behaviour in terms of dynamics (pumping or fuelling areas) and fuel content. A methodology based on modelling is introduced to perform such initialisation. A synthetic plasma pulse is built from consecutive SolEdge2D-EIRENE simulations. This synthetic pulse is used as a plasma background for the D-WEE module. A sequence of plasma pulses is simulated with D-WEE to model a tokamak operation. This simulation enables to extract at a desired time during a pulse the local fuel inventory and the local desorption flux density which could be used as initial condition for coupled plasma-wall simulations. To assess the relevance of the dynamic retention behaviour obtained in the simulation, a confrontation to post-pulse experimental pressure measurement is performed. Such confrontation reveals a qualitative agreement between the temporal pressure drop obtained in the simulation and the one observed experimentally. The simulated dynamic retention during the consecutive pulses is also studied.Peer reviewe

Beryllium global erosion and deposition at JET-ILW simulated with ERO2.0

The recently developed Monte-Carlo code ERO2.0 is applied to the modelling of limited and diverted discharges at JET with the ITER-like wall (ILW). The global beryllium (Be) erosion and deposition is simulated and compared to experimental results from passive spectroscopy. For the limiter configuration, it is demonstrated that Be self-sputtering is an important contributor (at least 35%) to the Be erosion. Taking this contribution into account, the ERO2.0 modelling confirms previous evidence that high deuterium (D) surface concentrations of up to similar to 50% atomic fraction provide a reasonable estimate of Be erosion in plasma-wetted areas. For the divertor configuration, it is shown that drifts can have a high impact on the scrape-off layer plasma flows, which in turn affect global Be transport by entrainment and lead to increased migration into the inner divertor. The modelling of the effective erosion yield for different operational phases (ohmic, L- and H-mode) agrees with experimental values within a factor of two, and confirms that the effective erosion yield decreases with increasing heating power and confinement.Peer reviewe