Este trabalho propõe uma metodologia de identificação para sistemas lineares sujeitos a saltos markovianos. Dada uma sequência de observações ruidosas da variável de estados, busca-se estimá-la juntamente com os parâmetros (desconhecidos) que descrevem o sistema dinâmico no espaço de estados. Como é bem conhecido, a ltragem ótima nesta classe de sistemas tem requisitos computacionais exponencialmente crescentes em função do tamanho da amostra, e torna-se inviável na prática. Recorre-se, portanto, a um algoritmo sub-ótimo de ltragem, cujos resultados são utilizados na identificação por máxima verossimilhança segundo a metodologia apresentada. Simulações realizadas mostram boa convergência. / This paper proposes a methodology for the identification of Markov-jump linear systems. Given a sequence of noisy observations of the state variable, our objective is to estimate it along with the (unknown) parameters that drive the system in the state-space. As it is well known, the optimal ltering in this class of systems requires exponentially increasing computing power, in proportion to the sample size, and is not feasible in practice. We resort, therefore, to a sub-optimal algorithm, whose results are used for a maximum likelihood identification according to the methodology presented here. Simulations show a good convergence.

Este trabalho propõe uma metodologia de identificação para sistemas lineares sujeitos a saltos markovianos. Dada uma sequência de observações ruidosas da variável de estados, busca-se estimá-la juntamente com os parâmetros (desconhecidos) que descrevem o sistema dinâmico no espaço de estados. Como é bem conhecido, a ltragem ótima nesta classe de sistemas tem requisitos computacionais exponencialmente crescentes em função do tamanho da amostra, e torna-se inviável na prática. Recorre-se, portanto, a um algoritmo sub-ótimo de ltragem, cujos resultados são utilizados na identificação por máxima verossimilhança segundo a metodologia apresentada. Simulações realizadas mostram boa convergência. / This paper proposes a methodology for the identification of Markov-jump linear systems. Given a sequence of noisy observations of the state variable, our objective is to estimate it along with the (unknown) parameters that drive the system in the state-space. As it is well known, the optimal ltering in this class of systems requires exponentially increasing computing power, in proportion to the sample size, and is not feasible in practice. We resort, therefore, to a sub-optimal algorithm, whose results are used for a maximum likelihood identification according to the methodology presented here. Simulations show a good convergence.

Text in Afrikaans / Summaries in Afrikaans and English / This study aims to investigate and explain how the L2 -facilitator can effectively employ the various facilitation skills of language teaching in Afrikaans Second Language within the Outcomes Based Education framework in the learner-centred classroom. The facilitator is critical in providing an opportunity for multicultural learners to develop the necessary language learning skills to enjoy Afrikaans Second Language/Additional Language learning as an interesting learning experience within a positive learning milieu. In the learner-centred U -classroom, learners too must accept responsibility for their own and their peers' learning within the co-operative learning group. This study reveals how the L2 -facilitator can develop the necessary knowledge and skills concerning groupwork, such as the strategies enhancing L 2 -learning, effective group facilitation skills, learner attitudes towards the facilitator, problem-solving skills, co-operative learning as a control technique, communication, learners' behaviour and the advantages of groupwork. Furthermore, elements of classroom negotiation and the facilitator's methods of working in this negotiated partnership are also discussed. Since language learning is integral to lifelong learning, multicultural learners must be motivated to learn Afrikaans Second/ Additional language with greater enthusiasm. This necessitates the L2 -facilitator creating an interesting, challenging and authentic language learning environment where mutual respect and trust are emphasised. This study reveals how the L2 -facilitator could develop his/her knowledge of task-based L2 -teaching and use it with the effective techniques of facilitation and negotiation skills in the taskorientated second language classroom to lead learners to effective Afrikaans L2 -learning. The new National Language Standardisation Policy 200112002 necessitates the facilitator of Afrikaans L 2 -teaching/learning within the Outcomes Based Education framework and the revised Curriculum 2005 to be aufait with assessment and his/her role in assessment. Being knowledgeable on the various criteria and strategies regarding assessment is therefore imperative. Finally, chapter five illustrates practically how the facilitator could plan, organise, base, integrate and present authentic Afrikaans L 2 -lessons/work based on the theoretical knowledge and aspects of facilitation skills, group-work, task-based learning and assessment discussed in chapters two to four. / Daar word in die studie gepoog om te ondersoek en te verduidelik hoe die T2-fasiliteerder die verskillende fasiliteringsvaardighede ten opsigte van T2 -Afrikaansonderrig binne die UGO -raamwerk in die leerdergesentreerde T2-klaskamer effektief kan gebruik. Die fasiliteerder behoort sy multikulturele leerders die geleentheid te gun om die nodige taalleervaardighede te ontwikkel sodat hulle Afrikaans Tweedetaalleer/ Addisionele Taalleer as 'n interessante leerervaring binne 'n positiewe leerklimaat kan geniet. In die leerdergesentreerde T2 -klaskamer moet die leerders ook die verantwoordelikheid vir bulle eie leer, en vir die leer van ander leerders binne kooperatiewe leergroepe kan aanvaar. Die wyse waarop die fasiliteerder van T2-leer die nodige kennis en vaardighede ten opsigte van groepwerk kan ontwikkel, word deur die studie aan die lig gebring. Die verskillende strategiee wat die aanleer van die tweedetaal binne groepwerk bevorder, effektiewe groepsfasiliteringsvaardighede, leerders se gesindhede teenoor die fasiliteerder, die probleemoplossingsvaardighede, kooperatiewe leer as beheertegniek, kommunikasie, leerdergedragswyses en die voordele van groepwerk kom aan bod. Elemente van klaskameronderhandeling en die fasiliteerder se werkswyse in die onderhandelingsvennootskap word ook bespreek. Aangesien taalleer 'n integrale faset van lewenslange leer vorm, moet multikulturele leerders gemotiveer word om Afrikaans Tweedetaal/ Addisionele Taal op 'n meer entoesiastiese wyse te kan leer. Die T2 -fasiliteerder moet 'n interessante, uitdagende, outentieke taalleeromgewing skep waarin wedersydse respek en vertroue beklemtoon word. Die studie toon die wyse aan waarop die T2 -fasiliteerder sylhaar kennis in verband met taakgerigte T2 -onderrig kan ontwikkel en dit met die effektiewe fasiliteringstegnieke en onderhandelingsvaardighede in die taakgeorienteerde T2-klaskamer kan kombineer en gebruik om leerders tot effektiewe T2 -Afrikaansleer/ Addisionele Taalleer te kan lei. Die nuwe Nasionale Taalstandaardiseringsbeleid 2001/2002 vereis dat die fasiliteerder van T2-Afrikaansonderrig/-leer binne die UGO -raamwerk en die hersiene Kurrikulum 2005 deeglike kennis moet dra van assessering en sylhaar rol in assessering. Deeglike kennis ten opsigte van die verskillende assesseringskriteria en assesseringstegnieke is dus noodsaaklik. Daar word in hoofstuk vyf aangetoon op watter wyse die fasiliteerder outentieke praktiese T2-Afrikaanslesse/-werk, kan beplan, organiseer en dit op die teoretiese kennis en aspekte ten opsigte van fasiliteringsvaardighede, groepwerk, taakgerigte leer en assessering wat in hoofstukke twee tot vier bespreek word, kan toepas en geintegreerd kan aanbied. / Afrikaans and Theory of Literature / D.Litt. et Phil. (Afrikaans)