From 1990 to 1993 I was engaged as the Information Technology (IT) Workshop manager at Mid-Cornwall College, St. Austell. My mission during this period was to develop a new kind of IT learning environment. The main purpose was - and continues to be - to provide for mixed 'open-access’ student targets wishing to pursue generic IT activities and gain commensurate vocational qualifications. This Open-Learning (OL) environment provides on-the-job curriculum development of IT learning support systems, through a Flexible Learning (FL) management policy. An action research approach based on S-O-L provides both the methodology and technology for implementing a learning organisation. A key objective was institutional change towards the learning management policy of IT, through appropriate deployment of staffing and courseware resources to enable the practice of student centred learning. Another aim was to integrate and mix all target groups of learners together in the same domain, i. e. school leavers with adult returners for the achievement of a cost-effective, well-co-ordinated and productive learning environment. My action research applied the Centre for the Study of Human Learning's (CSHL's) ideas and tools towards the development of the IT Workshop's learning policy. I have sought to make the connection between FL delivery of the generic IT curriculum and the SOL approach towards individual and organisational learning. This came about from the link between the FL philosophy of learner-centred activity and the SOL philosophy of empowering individuals via Learning Conversations. S-O-L'Systems-7' was adopted as a conversational tool for developing the educational roles and practices of the IT Workshop. This influenced my college to make essential environmental changes to the workshop in order to develop these activities. The project also used the Personal Learning Contract (PLC) to manage and enable the 'learning-to-learn' activities of individual IT learners. With the PLC as the central tool for implementing Learning Conversations, there evolved the idea of 'Group Learning Contracts' (GLCs). This led to the practical development of 'Learning Plans' (LPs), such that IT flexible modules could be transferred to the autonomy of the learner. Evaluations from this project included sample case-study evidences of Learning Conversations obtained from individual IT case-load students. Repertory grid feedback conversations of learning experienced by individual staff members taking part in the project were also obtained. Questionnaire results from IT learners was used as another method of feedback, and conversationally evaluated using factor analysis and 'talkback' records. All the action research qualitative evidences were finally analysed using conversational techniques, leading to the overall project 'findings'.

This thesis develops methods of task localization, task similarity discovery, and task transfer for eventual use in a reinforcement learning task library system, which can effectively “learn to learn,” improving its performance as it encounters various tasks over the lifetime of the learning system.

No description available.

Baigiamasis darbas skirtas mokinių mokymosi mokytis kompetencijos ugdymo ypatumų analizei mokytojų ir tėvų bendradarbiavimo aspektu. Šiuolaikinė mokymosi paradigma pabrėžia savarankiško ir atsakingo mokinio mokymosi reikšmę. Tėvų ir pedagogų bendradarbiavimo tyrimas svarbus kaip mokinio mokymosi mokytis kompetencijos ugdymo veiksnys, įgalinantis mokinį patį savarankiškai siekti aukštesnių mokslo rezultatų. Tyrimo objektas: mokinių mokymosi mokytis kompetencijos ugdymas mokytojų ir tėvų bendradarbiavimo aspektu. Tyrimo tikslas: atskleisti mokinių mokymosi mokytis kompetencijos ugdymo ypatumus mokytojų ir tėvų bendradarbiavimo aspektu. Tyrimo metodai: mokslinės literatūros analizė; pusiau struktūrizuotas interviu; kokybinė (content) duomenų analizė. Tyrime dalyvavo: Vilkaviškio pagrindinę mokyklą lankančių vaikų tėvai ir šioje mokykloje dirbantys pedagogai. Viso - 20 tėvų ir 20 pedagogų. / The training of pupil‘s learning to The training of pupil‘s learning to learn competence through the aspect of teachers and parents collaboration. Undergraduate work through the aspect of teachers and parents collaboration Undergraduate work. The peculiarities of the pupil‘s learning to learn competence training through the aspect of teachers and parents collaboration are analysed in this undergraduate work.. The contemporary learning paradigm underlines the significance of autonomous and responsible scholar‘s learning. The parents and teachers collaboration research is important factor of the learning to learn competence training, empowering scholar to search for higher educational results by oneself.Research object: the training of pupil‘s learning to learn competence through the aspect of teachers and parents collaboration.Research goal: to reveal the peculiarities of the pupil‘s learning to learn competence training through the aspect of teachers and parents collaboration.Research methods: the analysis of the scientific literature; semi –structured interview; qualitative (content) analysis. Research participants: The Vilkaviskis main school pupil‘s parents and teachers. Totally - 20 parents and 20 teachers.

Given the "right" representation, learning is easy. This thesis studies representation learning and meta-learning, with a special focus on sparse representations. Meta-learning is fundamental to machine learning, and it translates to learning to learn itself. The presentation unfolds in two parts. In the first part, we establish learning theoretic results for learning sparse representations. The second part introduces new multi-task and meta-learning paradigms for representation learning. On the sparse representations front, our main pursuits are generalization error bounds to support a supervised dictionary learning model for Lasso-style sparse coding. Such predictive sparse coding algorithms have been applied with much success in the literature; even more common have been applications of unsupervised sparse coding followed by supervised linear hypothesis learning. We present two generalization error bounds for predictive sparse coding, handling the overcomplete setting (more original dimensions than learned features) and the infinite-dimensional setting. Our analysis led to a fundamental stability result for the Lasso that shows the stability of the solution vector to design matrix perturbations. We also introduce and analyze new multi-task models for (unsupervised) sparse coding and predictive sparse coding, allowing for one dictionary per task but with sharing between the tasks' dictionaries. The second part introduces new meta-learning paradigms to realize unprecedented types of learning guarantees for meta-learning. Specifically sought are guarantees on a meta-learner's performance on new tasks encountered in an environment of tasks. Nearly all previous work produced bounds on the expected risk, whereas we produce tail bounds on the risk, thereby providing performance guarantees on the risk for a single new task drawn from the environment. The new paradigms include minimax multi-task learning (minimax MTL) and sample variance penalized meta-learning (SVP-ML). Regarding minimax MTL, we provide a high probability learning guarantee on its performance on individual tasks encountered in the future, the first of its kind. We also present two continua of meta-learning formulations, each interpolating between classical multi-task learning and minimax multi-task learning. The idea of SVP-ML is to minimize the task average of the training tasks' empirical risks plus a penalty on their sample variance. Controlling this sample variance can potentially yield a faster rate of decrease for upper bounds on the expected risk of new tasks, while also yielding high probability guarantees on the meta-learner's average performance over a draw of new test tasks. An algorithm is presented for SVP-ML with feature selection representations, as well as a quite natural convex relaxation of the SVP-ML objective.

Notre environnement est complexe et changeant, ce qui apporte de l'incertitude dans les décisions de tous les jours. La capacité de détecter et résoudre l'incertitude est cruciale pour un comportement flexible et adapté. Notre hypothèse est que l'efficacité et la flexibilité comportementale en situation d'incertitude dépendent de la façon dont l'individu a appris à apprendre. Dans une 1ère étude, trois singes ont acquis un learning set pour une tâche aux règles stochastiques et changeantes. Leur réactivité aux évènements inattendus a augmenté lors de l'apprentissage, suivant l'évolution du degré d'incertitude environnementale. Cela a permis un transfert sans coût à une tâche plus complexe partageant la même structure, suggérant que les singes ont appris à apprendre la structure statistique de l'environnement. Nous avons ensuite étudié les mécanismes cérébraux sous-jacents à ce comportement flexible. Deux animaux ont reçu un implant d'électrocorticographie, sur les aires frontales et pariétales. Nous montrons d'abord, avec les données d'un animal, que des potentiels évoqués au feedback sont sensibles à la valence et au degré de surprise du feedback, et prédisent la stratégie à venir. Ensuite, nous présentons des résultats préliminaires montrant que des oscillations dans les bandes beta et thêta sont présentes au moment du feedback et de la décision, et que leur puissance est modulée de manière différente par les facteurs de la tâche. Ces résultats contribuent à révéler la complexité du réseau frontal pour la flexibilité comportementale, et ouvrent la voie à de nouvelles expériences pour comprendre comment ces mécanismes sont façonnés au cours du processus d'apprendre à apprendre / Our environment is both complex and changing, which triggers uncertainty in every decision we make. The ability to detect and solve the resulting uncertainty is crucial for adapted and flexible behavior. Our hypothesis is that behavioral efficiency and flexibility in an uncertain environment depend on the way the agent has learnt to learn. In a first study, 3 macaque monkeys developed a learning-set for a task with stochastic and changing rules. Monkey’s reactivity to unexpected feedback increased across learning and paralleled the evolution of the degree of environmental uncertainty. This enabled them to transfer, without cost, to a more complex task with the same structure, suggesting that they learned to learn the statistical structure of the environment. We then studied the cerebral mechanisms underpinning this flexible behavior. Two animals were implanted with an electrocorticography implant over the frontal and parietal areas. We first showed, using data from one animal, that feedback related potentials were sensitive to feedback valence and unexpectedness, and predictive of the upcoming behavioral strategy. Then, we present preliminary results showing that oscillations in the beta and theta bands can be recorded at the time of feedback and at the time of decision, and that their power is modulated differently depending on the various task factors. These results contribute to reveal the complexity of the frontal cortical network enabling behavioral flexibility and open new horizons for future research to understand how these mechanisms are shaped throughout the learning to learn process

The target school used embedded study skills in Algebra I classes to improve attitudes toward mathematics. The purpose of this sequential, explanatory mixed-methods study was to examine the effect of embedded study-skills instruction on students' attitudes toward mathematics. Metacognitive theory was used for this study's framework. Participants were 28 Grade 9 and 10 students who repeated Algebra I. Quantitative data from the Attitudes Toward Mathematics Inventory assessed students' pre- and post-instruction attitudes toward mathematics in 4 domains. Data were analyzed using 4 independent samples t tests for students who did and did not receive embedded instruction. Qualitative data were collected through a semi structured group interview to explore 6 students' perceptions on how the intervention affected their attitudes toward mathematics. Open and axial coding strategies were used to develop themes. Quantitative results indicated no significant differences in students' attitudes toward mathematics, while qualitative findings supported the use of the intervention to develop students' positive attitudes in mathematics. A recommendation was that educators undergo professional learning opportunities to increase awareness of the impact of embedded study skills on student learning and how to use this instruction in lessons. Positive social change may occur if educators are provided with insight in embedded study skills that could improve students' attitudes toward mathematics, which ultimately may encourage students to study higher level mathematics and to pursue mathematics-based careers.

Darbo tema – mokėjimo mokytis kompetencijos ugdymas ir vertinimas. Darbe nagrinėjama šiuolaikinio ugdymo proceso samprata, mokėjimo mokytis kompetencijos samprata ir struktūra, apžvelgiami mokėjimo mokytis kompetencijos vertinimo įrankiai. Darbo tikslas – išnagrinėti mokėjimo mokytis kompetencijos ugdymą ir vertinimą pedagogų ir mokinių požiūriu. Uždaviniai: 1. Pateikti šiuolaikinio ugdymo proceso sampratą. 2. Atskleisti mokėjimo mokytis kompetencijos apibrėžimą ir struktūrą. 3. Apžvelgti mokėjimo mokytis kompetencijos vertinimo įrankius. 4. Ištirti mokinių ir mokytojų požiūrį į mokėjimo mokytis kompetencijos ugdymą ir vertinimą. Tyrimo metodai. Teoriniai: mokslinės literatūros analizė, apibendrinimas Empiriniai: pusiau struktūruotas interviu. Tiriamieji. Tyrime dalyvavo Vilniaus X gimnazijos 7 mokytojos ir 12 mokinių 5 – 6 ir 9 – 12kl. Tiriamieji pasirinkti atsižvelgiant į jų sutikimą dalyvauti tyrime. Empiriniai tyrimo rezultatai. Remiantis tyrimo rezultatais nustatyta, kad mokėjimo mokytis kompetenciją mokytojai apibrėžia vienpusiškai kaip informacijos radimą, atrinkimą bei pritaikymą. Nors mokytojai mokėjimo mokytis kompetenciją ugdo ir vertina įvairiais metodais, praktinėmis užduotimis, tačiau iš tyrimo rezultatų matyti, kad dar neįsitvirtina mokėjimo mokytis kompetencija ir mokytojai dažnu atveju linkę dominuoti pamokoje. Mokėjimo mokytis kompetencijos prasmę informantės suvokia per mokymosi visą gyvenimą koncepciją bei asmenybės ugdymą. Mokiniai kelia... [toliau žr. visą tekstą] / Scientific thesis – learning to learn competence development and assessment. In this work analyze modern educational process, learning to learn competence conception and structure, gives an overview of learning to learn competence assessment tools. The aim of this work – analyze learning to learn competence development and assessment of teachers and student point of view. Tasks: 1. Submit a modern concept of the educational process. 2. Reveal learning to learn competence definition and structure. 3. Overview of learning ti learn competence assessment tools. 4. Investigate the students and teachers attitudes to learning to learn competence development and assessment. Research methods: Theoretical methods: scientific literature analysis, generalization Empirical methods: semi – structured interview. Participants. In the research participated seven teachers and twelve students 5-6 and 9 – 12 classes from Vilnius X gymnasium. Participants selected according to their agreements to participate in the research. Empirical reserch results. Research results revealed that learning to learn competence teachers as defined by one-sided information discovery, selection and adaptation. Although teachers the learning to learn competence and develop and assess of various methods, practical tasks, but research shows that it is not popular at school and teachers often dominate in the lesson. Informants understand the meaning of learning to learn competence through lifelong learning concept and... [to full text]

A presente pesquisa versa sobre o aprender a aprender dos diferentes sujeitos/atores em situações de ensino problematizadoras e diversificadas, produzidas na dinâmica do contexto escolar. A aprendizagem, neste estudo, é considerada como um “evento” relacionado à diferentes contextos histórico-culturais, em uma unidade dinâmica, cujos sujeitos-atores estão inseridos, provocando múltiplas situações produtoras da aprendizagem. As situações e as interações entre os sujeitos envolvidos no ato de aprender, foram problematizadas em uma escola pública de Porto Alegre/RS, o Colégio Estadual Júlio de Castilhos, entre 2011 e 2013, junto aos alunos de 1º ano do ensino médio na disciplina de biologia, e a estudantes do Instituto Federal de Educação, Ciência e Tecnologia (IFRS-campus Porto Alegre), do curso de Licenciatura em Ciências da Natureza: Química e Biologia, participantes do PIBID (Programa Institucional de Bolsas de Iniciação à Docência), entre julho de 2012 a dezembro de 2013. Na perspectiva de uma pesquisa em ação, foram analisados os conceitos construídos (os invariantes operatórios), e identificou-se as dificuldades para determinar as situações-problema mais adequadas para promover as conceituações em ciências. Mas nas interações que se estabelecem dialeticamente na escola, o professor também aprende, modifica-se. É na sala de aula que este professor irá desenvolver o seu processo investigativo para aprender a ensinar, construindo conceitos relacionados ao ensino de ciências, em um aprender a aprender. No processo de aprender a aprender, o professor compreende a dinâmica relacionada ao aprender a aprender do estudante. Nas dificuldades da aprendizagem de alunos e professores formados e em formação, a professora investigadora modificou-se através da reflexão sobre as suas próprias dificuldades de aprendizagem para resolver as situações-problema, no enfoque de Gérard Vergnaud (1990), dos campos conceituais. Nesta análise, o conhecimento está organizado em situações-problema, e é a partir da resolução destas situações que os sujeitos que aprendem, desenvolverão as suas conceituações. O contexto de ensino dos formadores de professores também é problematizado nesta pesquisa. Nas investigações de formação inicial e continuada, as situações/contextos sociais direcionaram a aprendizagem em ciências, reforçando a ideia de que aprender a aprender através da ressignificação dos conceitos prévios em situações problematizadoras, é fundamental para aprender a ensinar. Quando não existe esta conexão, identificam-se dificuldades para a aprendizagem do professor, pois ele simplesmente repete sem significação alguns conceitos transmitidos na academia, reproduzindo muitas vezes, a metodologia tradicional de ensino. Constatou-se neste estudo, que um professor que não é formado em um contexto investigativo, onde a sua prática na sala de aula não é o fundamento para elaboração de conhecimentos ressignificados da academia, é um professor que provavelmente, não reconhece como elemento para a aprendizagem de seus alunos, a investigação. Portanto, o aprender e o ensinar ciências se realizam no contexto cuja essência deve ser a investigação, pois é permeado por situações de ensino que se constituem no contexto histórico-cultural dos sujeitos da aprendizagem. As argumentações desta tese foram fundamentadas a partir da reflexão-ação nos referenciais de Vergnaud (1990, 2003), Ausubel (1980, 2000), Vygotsky (!988), Moreira (2002, 2011), Freire (2004), Demo (1999), Nóvoa (1992) e Schön (1997). / The study deals on the learning to learn of the different subjects/actors in teaching situations problematizing and diversified, produced in the dynamics of the school context. Learning, in this study, it is considered as an "event" related to different contexts historical-cultural in a dynamic unity, whose subject-actors are inserted, causing multiple situations producing learning. The situations and the interactions between the individuals involved in the act of learning, were analyzed in a public school in Porto Alegre/RS, the State College Julio de Castilhos, between 2011 and 2013, together with the students of 1ST year of secondary education in the discipline of biology, and the students of the Federal Institute of Education, Science and Technology (IFRS-campus Porto Alegre), of degree course in Natural Sciences: Chemistry and Biology, participants of PIBID (Institutional Program of Scholarships to Teaching), between july 2012 and december 2013. From the perspective of a research in action, were análisados concepts built (the invariant operative), and we identified the difficulties to determine the problem situations most suitable to promote the conceptions in sciences. But in the interactions that are dialectically in the school, the teacher also learns, modifies itself. It is in the classroom that the teacher will develop your investigative process to learn how to teach, constructing concepts related to the teaching of science, in a learning to learn. In the process of learning to learn, the teacher understands the dinâmca related to learning to learn of student. In the learning difficulties of students and teachers trained and training, the teacher researcher has changed through reflection of their own learning difficulties to solve problem situations, at focus of Gérard Vergnaud (1990), in the conceptual fields. In this analysis, the knowledge is organized in problem situations, and is from the resolution of these situations that the subjects who learn, develop their conceptualizations. The context of teaching the teacher trainers also is problematized in this research. In investigations of initial and continuing training, the situations / social contexts has influenced learning in sciences, reinforcing the idea that learning to learn through the Resignification of the previous concepts in problem-solving situations, it is essential to learn to teach. When there not is this connection, identifies difficulties for the learning of the teacher, because he simply repeats without signification some concepts transmitted in the academy, reproducing often many times, the traditional methodology of teaching. It was found in this study that a teacher who is not formed in a research context, where his practice in the classroom not the basis for the elaboration of new meanings of academic knowledge, is a teacher who probably does not recognize as an element for the learning of their students, research. Therefore, the learning and teaching science if perform in the context whose essence must be the research, because it is permeated by teaching situations that is constitute in the historical-cultural context of the subjects of learning. The arguments of this thesis were based from the reflection-action on reference Vergnaud (1990, 2003), Ausubel (1980, 2000), Vygotsky (! 988), Moreira (2002, 2011), Freire (2004), Demo (1999) Nóvoa (1992) and Schon (1997).

A presente pesquisa versa sobre o aprender a aprender dos diferentes sujeitos/atores em situações de ensino problematizadoras e diversificadas, produzidas na dinâmica do contexto escolar. A aprendizagem, neste estudo, é considerada como um “evento” relacionado à diferentes contextos histórico-culturais, em uma unidade dinâmica, cujos sujeitos-atores estão inseridos, provocando múltiplas situações produtoras da aprendizagem. As situações e as interações entre os sujeitos envolvidos no ato de aprender, foram problematizadas em uma escola pública de Porto Alegre/RS, o Colégio Estadual Júlio de Castilhos, entre 2011 e 2013, junto aos alunos de 1º ano do ensino médio na disciplina de biologia, e a estudantes do Instituto Federal de Educação, Ciência e Tecnologia (IFRS-campus Porto Alegre), do curso de Licenciatura em Ciências da Natureza: Química e Biologia, participantes do PIBID (Programa Institucional de Bolsas de Iniciação à Docência), entre julho de 2012 a dezembro de 2013. Na perspectiva de uma pesquisa em ação, foram analisados os conceitos construídos (os invariantes operatórios), e identificou-se as dificuldades para determinar as situações-problema mais adequadas para promover as conceituações em ciências. Mas nas interações que se estabelecem dialeticamente na escola, o professor também aprende, modifica-se. É na sala de aula que este professor irá desenvolver o seu processo investigativo para aprender a ensinar, construindo conceitos relacionados ao ensino de ciências, em um aprender a aprender. No processo de aprender a aprender, o professor compreende a dinâmica relacionada ao aprender a aprender do estudante. Nas dificuldades da aprendizagem de alunos e professores formados e em formação, a professora investigadora modificou-se através da reflexão sobre as suas próprias dificuldades de aprendizagem para resolver as situações-problema, no enfoque de Gérard Vergnaud (1990), dos campos conceituais. Nesta análise, o conhecimento está organizado em situações-problema, e é a partir da resolução destas situações que os sujeitos que aprendem, desenvolverão as suas conceituações. O contexto de ensino dos formadores de professores também é problematizado nesta pesquisa. Nas investigações de formação inicial e continuada, as situações/contextos sociais direcionaram a aprendizagem em ciências, reforçando a ideia de que aprender a aprender através da ressignificação dos conceitos prévios em situações problematizadoras, é fundamental para aprender a ensinar. Quando não existe esta conexão, identificam-se dificuldades para a aprendizagem do professor, pois ele simplesmente repete sem significação alguns conceitos transmitidos na academia, reproduzindo muitas vezes, a metodologia tradicional de ensino. Constatou-se neste estudo, que um professor que não é formado em um contexto investigativo, onde a sua prática na sala de aula não é o fundamento para elaboração de conhecimentos ressignificados da academia, é um professor que provavelmente, não reconhece como elemento para a aprendizagem de seus alunos, a investigação. Portanto, o aprender e o ensinar ciências se realizam no contexto cuja essência deve ser a investigação, pois é permeado por situações de ensino que se constituem no contexto histórico-cultural dos sujeitos da aprendizagem. As argumentações desta tese foram fundamentadas a partir da reflexão-ação nos referenciais de Vergnaud (1990, 2003), Ausubel (1980, 2000), Vygotsky (!988), Moreira (2002, 2011), Freire (2004), Demo (1999), Nóvoa (1992) e Schön (1997). / The study deals on the learning to learn of the different subjects/actors in teaching situations problematizing and diversified, produced in the dynamics of the school context. Learning, in this study, it is considered as an "event" related to different contexts historical-cultural in a dynamic unity, whose subject-actors are inserted, causing multiple situations producing learning. The situations and the interactions between the individuals involved in the act of learning, were analyzed in a public school in Porto Alegre/RS, the State College Julio de Castilhos, between 2011 and 2013, together with the students of 1ST year of secondary education in the discipline of biology, and the students of the Federal Institute of Education, Science and Technology (IFRS-campus Porto Alegre), of degree course in Natural Sciences: Chemistry and Biology, participants of PIBID (Institutional Program of Scholarships to Teaching), between july 2012 and december 2013. From the perspective of a research in action, were análisados concepts built (the invariant operative), and we identified the difficulties to determine the problem situations most suitable to promote the conceptions in sciences. But in the interactions that are dialectically in the school, the teacher also learns, modifies itself. It is in the classroom that the teacher will develop your investigative process to learn how to teach, constructing concepts related to the teaching of science, in a learning to learn. In the process of learning to learn, the teacher understands the dinâmca related to learning to learn of student. In the learning difficulties of students and teachers trained and training, the teacher researcher has changed through reflection of their own learning difficulties to solve problem situations, at focus of Gérard Vergnaud (1990), in the conceptual fields. In this analysis, the knowledge is organized in problem situations, and is from the resolution of these situations that the subjects who learn, develop their conceptualizations. The context of teaching the teacher trainers also is problematized in this research. In investigations of initial and continuing training, the situations / social contexts has influenced learning in sciences, reinforcing the idea that learning to learn through the Resignification of the previous concepts in problem-solving situations, it is essential to learn to teach. When there not is this connection, identifies difficulties for the learning of the teacher, because he simply repeats without signification some concepts transmitted in the academy, reproducing often many times, the traditional methodology of teaching. It was found in this study that a teacher who is not formed in a research context, where his practice in the classroom not the basis for the elaboration of new meanings of academic knowledge, is a teacher who probably does not recognize as an element for the learning of their students, research. Therefore, the learning and teaching science if perform in the context whose essence must be the research, because it is permeated by teaching situations that is constitute in the historical-cultural context of the subjects of learning. The arguments of this thesis were based from the reflection-action on reference Vergnaud (1990, 2003), Ausubel (1980, 2000), Vygotsky (! 988), Moreira (2002, 2011), Freire (2004), Demo (1999) Nóvoa (1992) and Schon (1997).