Modelling, control and supervision for a class of hybrid systems

The aim of this thesis is to narrow the gap between two different control techniques: the continuous control and the discrete event control techniques DES. This gap can be reduced by the study of Hybrid systems, and by interpreting as Hybrid systems the majority of large-scale systems. In particular, when looking deeply into a process, it is often possible to identify interaction between discrete and continuous signals. Hybrid systems are systems that have both continuous, and discrete signals. Continuous signals are generally supposed continuous and differentiable in time, since discrete signals are neither continuous nor differentiable in time due to their abrupt changes in time. Continuous signals often represent the measure of natural physical magnitudes such as temperature, pressure etc. The discrete signals are normally artificial signals, operated by human artefacts as current, voltage, light etc. Typical processes modelled as Hybrid systems are production systems, chemical process, or continuos production when time and continuous measures interacts with the transport, and stock inventory system. Complex systems as manufacturing lines are hybrid in a global sense. They can be decomposed into several subsystems, and their links. Another motivation for the study of Hybrid systems is the tools developed by other research domains. These tools benefit from the use of temporal logic for the analysis of several properties of Hybrid systems model, and use it to design systems and controllers, which satisfies physical or imposed restrictions. This thesis is focused in particular types of systems with discrete and continuous signals in interaction. That can be modelled hard non-linealities, such as hysteresis, jumps in the state, limit cycles, etc. and their possible non-deterministic future behaviour expressed by an interpretable model description. The Hybrid systems treated in this work are systems with several discrete states, always less than thirty states (it can arrive to NP hard problem), and continuous dynamics evolving with expression: with Ki ¡ Rn constant vectors or matrices for X components vector. In several states the continuous evolution can be several of them Ki = 0. In this formulation, the mathematics can express Time invariant linear system. By the use of this expression for a local part, the combination of several local linear models is possible to represent non-linear systems. And with the interaction with discrete events of the system the model can compose non-linear Hybrid systems. Especially multistage processes with high continuous dynamics are well represented by the proposed methodology. Sate vectors with more than two components, as third order models or higher is well approximated by the proposed approximation. Flexible belt transmission, chemical reactions with initial start-up and mobile robots with important friction are several physical systems, which profits from the benefits of proposed methodology (accuracy). The motivation of this thesis is to obtain a solution that can control and drive the Hybrid systems from the origin or starting point to the goal. How to obtain this solution, and which is the best solution in terms of one cost function subject to the physical restrictions and control actions is analysed. Hybrid systems that have several possible states, different ways to drive the system to the goal and different continuous control signals are problems that motivate this research. The requirements of the system on which we work is: a model that can represent the behaviour of the non-linear systems, and that possibilities the prediction of possible future behaviour for the model, in order to apply an supervisor which decides the optimal and secure action to drive the system toward the goal. Specific problems can be determined by the use of this kind of hybrid models are: - The unity of order. - Control the system along a reachable path. - Control the system in a safe path. - Optimise the cost function. - Modularity of control The proposed model solves the specified problems in the switching models problem, the initial condition calculus and the unity of the order models. Continuous and discrete phenomena are represented in Linear hybrid models, defined with defined eighth-tuple parameters to model different types of hybrid phenomena. Applying a transformation over the state vector : for LTI system we obtain from a two-dimensional SS a single parameter, alpha, which still maintains the dynamical information. Combining this parameter with the system output, a complete description of the system is obtained in a form of a graph in polar representation. Using Tagaki-Sugeno type III is a fuzzy model which include linear time invariant LTI models for each local model, the fuzzyfication of different LTI local model gives as a result a non-linear time invariant model. In our case the output and the alpha measure govern the membership function. Hybrid systems control is a huge task, the processes need to be guided from the Starting point to the desired End point, passing a through of different specific states and points in the trajectory. The system can be structured in different levels of abstraction and the control in three layers for the Hybrid systems from planning the process to produce the actions, these are the planning, the process and control layer. In this case the algorithms will be applied to robotics ¡V a domain where improvements are well accepted ¡V it is expected to find a simple repetitive processes for which the extra effort in complexity can be compensated by some cost reductions. It may be also interesting to implement some control optimisation to processes such as fuel injection, DC-DC converters etc. In order to apply the RW theory of discrete event systems on a Hybrid system, we must abstract the continuous signals and to project the events generated for these signals, to obtain new sets of observable and controllable events. Ramadge & Wonham¡¦s theory along with the TCT software give a Controllable Sublanguage of the legal language generated for a Discrete Event System (DES). Continuous abstraction transforms predicates over continuous variables into controllable or uncontrollable events, and modifies the set of uncontrollable, controllable observable and unobservable events. Continuous signals produce into the system virtual events, when this crosses the bound limits. If this event is deterministic, they can be projected. It is necessary to determine the controllability of this event, in order to assign this to the corresponding set, , controllable, uncontrollable, observable and unobservable set of events. Find optimal trajectories in order to minimise some cost function is the goal of the modelling procedure. Mathematical model for the system allows the user to apply mathematical techniques over this expression. These possibilities are, to minimise a specific cost function, to obtain optimal controllers and to approximate a specific trajectory. The combination of the Dynamic Programming with Bellman Principle of optimality, give us the procedure to solve the minimum time trajectory for Hybrid systems. The problem is greater when there exists interaction between adjacent states. In Hybrid systems the problem is to determine the partial set points to be applied at the local models. Optimal controller can be implemented in each local model in order to assure the minimisation of the local costs. The solution of this problem needs to give us the trajectory to follow the system. Trajectory marked by a set of set points to force the system to passing over them. Several ways are possible to drive the system from the Starting point Xi to the End point Xf. Different ways are interesting in: dynamic sense, minimum states, approximation at set points, etc. These ways need to be safe and viable and RchW. And only one of them must to be applied, normally the best, which minimises the proposed cost function. A Reachable Way, this means the controllable way and safe, will be evaluated in order to obtain which one minimises the cost function. Contribution of this work is a complete framework to work with the majority Hybrid systems, the procedures to model, control and supervise are defined and explained and its use is demonstrated. Also explained is the procedure to model the systems to be analysed for automatic verification. Great improvements were obtained by using this methodology in comparison to using other piecewise linear approximations. It is demonstrated in particular cases this methodology can provide best approximation. The most important contribution of this work, is the Alpha approximation for non-linear systems with high dynamics While this kind of process is not typical, but in this case the Alpha approximation is the best linear approximation to use, and give a compact representation.

As atitudes dos professores face à inclusão de alunos com deficiência no Ensino Regular

As sociedades actuais caracterizam-se pela mudança, complexidade e diversidade cultural. De dia para dia assistimos cada vez mais à passagem das responsabilidades educativas da comunidade para a escola, assumindo esta, um papel preponderante na formação dos nossos jovens. O professor, é assim, considerado um elemento chave na construção de uma escola inclusiva e para que haja uma efectiva mudança da escola e das estratégias da sala de aula (Costa, 1999). O objectivo deste estudo é investigar as atitudes dos professores, determinando como estes percepcionam as suas Competências e de que forma essas atitudes são influenciadas, ou não, tendo em conta a experiência profissional, o grupo disciplinar a que pertencem, a experiência no ensino de alunos com deficiência e a formação inicial cujas áreas de estudo, estiveram directamente relacionados com a deficiência. A amostra deste estudo foi constituída por um total de 741 professores do ensino regular (534 afectos ao género feminino e 207 afectos ao género masculino). Foi aplicado o questionário APIAD – Atitudes dos Professores face à Inclusão de Alunos com Deficiência (Leitão, 2011), inferido através da resposta a 14 afirmações, em que cada uma delas deverá ser relacionado com 4 condições de deficiência (deficiência visual, deficiência auditiva, deficiência mental e deficiência motora). Concluiu-se então que, relativamente ao Grupo Disciplinar, as diferenças significativas se encontram entre os professores de Educação Física e os professores de Humanidades e de Ciências, sendo que os primeiros têm uma atitude mais positiva relativamente às suas competências. Quanto ao Contacto com a Deficiência, os resultados indicaram que os professores que têm experiência no ensino de alunos com deficiência têm uma atitude mais positiva relativamente às suas competências. No que se refere à Experiência Profissional, os nossos resultados encontram diferenças significativas entre os professores com menos anos de experiência e os professores com mais anos de experiência, sendo que os primeiros têm uma atitude mais positiva relativamente às suas competências Por último, em relação à Formação Inicial, os professores cujas áreas de estudo, na sua formação inicial, estiveram directamente relacionados com deficiência têm uma atitude mais positiva relativamente às suas competências. ABSTRACT: Today, societies are characterized by change, complexity and cultural diversity. Each day, we saw more and more responsibilities passing from the educational community to school, assuming that a major role in the formation of our youth. Teacher is considered a key element in the building of an inclusive school and for that there is a real change of school and classroom strategies (Costa, 1999). The purpose of this study is to investigate teacher´s attitudes, determining how they perceive their skills and how these attitudes are or aren´t influenced taking into account the professional experience, the subject group they belong to, the experience in students with those particular needs teaching and last, the initial training with chairs that had contact with people with needs. The study sample consisted in a total of 741 teachers of the regular education (534 allocated to the female and 207 assigned to the male gender). We used the questionnaire APIAD - Attitudes of teachers towards the Inclusion of Students with Disabilities (Leitão, 2011), inferred by the response to 14 statements, each one of them should be related to four conditions of disability (visual impairment, hearing impairment, mental retardation and physical disabilities). It was concluded then that for the Disciplinary Group, significant differences are found between the physical education teachers and teachers of Humanities and Sciences, and the former have a more positive attitude to their skills. How to contact the Disability, the results indicated that teachers who have experience teaching students with disabilities have a more positive attitude to their skills. With regard to professional experience, significant differences were found between teachers with fewer years of experience and teachers with more years of experience, and the former have a more positive attitude to their skills. Finally, regarding to initial training, teachers in their initial training formation who have contact with people with disabilities have a more positive attitude to their skills.

A prática do interacionismo sociodiscursivo da língua portuguesa escrita : projeto de reescrita textual

A dificuldade na produção da língua portuguesa escrita e a constante desmotivação dos alunos para escrever tem sido a grande preocupação dos educadores. Seguimos como fundamentação teórica da língua portuguesa escrita o interacionismo sociodiscursivo na abordagem da teoria de Bronckart e Bakhtin, o gênero discursivo segundo Bakhtin e a teoria do Habitus na concepção de Bourdieu, na intenção de reconhecer na língua escrita a manifestação concreta da competência linguística dos textos escolares e dos contextos sociais. Nessa perspectiva pretendemos analisar a prática interacionista sociodiscursiva e cognitiva da língua portuguesa escrita a partir dos textos dos alunos do ensino médio, e da reescrita dos textos de acordo com as orientações realizadas pelo professor. Conhecer o interacionismo sociodiscursivo na prática, nas produções textuais escritas dos alunos, foi o grande desafio da pesquisa. A partir da parte empírica foi possível verificar que os textos reescritos apresentaram avanço em vários aspectos, já que alguns alunos conseguiram sobressair em quesitos esperados pelo professor, mas outros alunos permaneceram presos ao primeiro texto sem modificação na estrutura ou argumentação, limitando-se às correções gramaticais. Nenhum aluno ousou recorrer a numa nova argumentação, ou ainda a uma nova estratégia em defesa dos argumentos propostos. Percebese a necessidade de novos caminhos que direcionem o professor em suas correções textuais capazes de motivarem os alunos a refletirem e que permitam que os alunos recorram à interação com o professor para melhorarem de maneira consciente as suas produções textuais.

Construindo pontes para a inclusão: um projeto de ensino/aprendizagem cooperativa

O presente trabalho constitui um projecto de investigação acção realizado numa escola de primeiro ciclo do distrito de Lisboa, mais especificamente numa truma do 4º ano de escolaridade,desencadeado por dois alunos diagnosticados com dificuldades intelectuais e desenvolvimentais que integravam uma unidade de apoio e specializado a alunos com multideficiência e surdocegueira congénita . Paralelamente foram também mobilizados os docentes do núcleo de educação especial do agrupamento de escolas . A caraterização destes três contextos a turma, a unidade e o núcleo- realizou-se através da utilização dos seguintei instrumentos de recolha de dados: análise documental, observação naturalista, entrevista semi-estruturada e sociometria. A análise dos mesmos permitiu fazer as seguintes constatações : turma bastante heterogénea, diferentes níveis de aprendizagem, alunos de língua portuguesa não materna, de diferentes etnias, e nível socioeconómico, problemas de relacionamento entre eles e alguma resistência em aceitar os colegas considerados com dificuldades intelectuais e desenvolvimentais; passividade e pouca responsabilidade no ato de aprender; dificuldades no cumprimento de regras; participação escassa das famílias no processo de ensino/aprendizagem; um tipo de ensino preferencialmente expositivo ; trabalho essencialmente individualizado , por parte dos alunos; dificuldade em incluir aqueles cujas diferenças individuais são mais significativas - diferenciação pedagógica descontextualizada . Na unidade de apoio especializado verificou –se a necessidade de um trabalho mais cooperado e convergente entre todos os intervenientes . No grupo de docentes de educação especial, constatou-se que as práticas de apoio aos sessenta alunos considerados com necessidades educativas especiais de caráter permanente eram essencialmente centradas no apoio direto ao aluno, fora da sala de aula .Tendo como quadro concetual de referência o paradigma da diversidade,a inclusão, a escola e educação inclusivas, a diferenciação pedagógica inclusiva, a aprendizagem cooperativa, e , tal como já se referiu, uma abordagem assente nas permissas da investigação ação como um processo cíclico de refletir para agir e refletir sobre a acção , desenvolveram –se ações nos referidos contextos da intervenção. Turma–diferenciação pedagógica inclusiva, utilização de metodologias de ensino/aprendizagem cooperativa na área da língua portuguesa Na unidade de apoio especializado –intervenção individualizada com os alunos “caso” para O desenvolvimento das competências estipuladas nos seus currículos específicos individuais, tendo por base um trabalho coordenado e cooperativo entre professores, famílias, assistentes operacionais e técnica de terapia da fala. No núcleo de educação especial – ação de sensibilização sobre a importância do papel de parceria pedagógica com os docentes do ensino regular , para implementação de uma pedagogia diferenciada inclusiva e da aprendizagem cooperativa como estratégias de inclusão . Considerando a complexidade dos contextos de intervenção e a competência profissional tão necessária ao sucesso de todos os alunos e à melhoria da escola , com a realização deste projeto de investigação acção pelo enriquecimento profissional que proporcionou, pôde constatar-se que este tipo de abordagem (o professor como investigador crítico e reflexivo), se apresenta de facto, como uma via importantíssimade formação contínua. Neste caso, o desenvolvimento deste projeto, permitiu encontrar algumas respostas que contribuíram para a melhoria profissional dos implicados e dos contextos em questão, atenuando os problemas identificados e perspetivar outras respostas . No entanto, esta abordagem não foi um processo fácil, pois esta capacidade de fazer juízos críticos sobre o próprio trabalho requer tempo de aprendizagem e principalmente a vontade de querer fazer, sempre, mais e melhor.

The study of prefixes and suffixes

This paper contains an outline of study for language development with prefixes and suffixes for hearing impaired children.

Structural analysis of narratives produced by normal-hearing and deaf children

This dissertation presents two experiments investigating the structural analysis of narratives produced by normal-hearing and hearing-impaired children. The results suggest that the evaluation of deaf children’s language at a discourse level is both possible and more relevant to academic achievement than traditional assessment procedures that focus on assessing language at a word, phrase or sentence level.

An experimental base to cognitive learning: its application in the education of young hearing-impaired children

This paper reviews a program of study for language development using a cognitive approach.

Influence of fibrolytic enzymes on the hydrolysis and fermentation of pure cellulose and xylan by mixed ruminal microorganisms in vitro

A series of in vitro studies was, conducted to determine the effects of adding a commercial enzyme product on the hydrolysis and fermentation of cellulose, xylan, and a mixture (1:1 wt/wt) of both. The enzyme product (Liquicell 2500, Specialty Enzymes and Biochemicals, Fresno, CA) was derived from Trichoderma reesei and contained mainly xylanase and cellulase activities. Addition of enzyme (0.5, 2.55 and 5.1 muL/g of DM) in the absence of ruminal fluid increased (P < 0.001) the release of reducing sugars from xylan and the mixture after 20 h of incubation at 20degreesC. Incubations with ruminal fluid showed that enzyme (0.5 and 2.55 muL/g of DM) increased (P < 0.05) the initial (up to 6 h) xylanase, endoglucanase, and beta-D-glucosidase activities in the liquid fraction by an average of 85%. Xylanase and endoglucanase activities in the solid fraction also were increased (P < 0.05) by enzyme addition, indicating an increase in fibrolytic activity due to ruminal microbes. Gas production over 96 h of incubation was determined using a gas pressure measurement technique. Incremental levels of enzyme increased (P < 0.05) the rate of gas production of all substrates, suggesting that fermentation of cellulose and xylan was enzyme-limited. However, adding the enzyme at levels higher than 2.55 muL/g of DM failed to further increase the rate of gas production, indicating that the maximal level of stimulation was already achieved at lower enzyme concentrations. It was concluded that enzymes enhanced the fermentation of cellulose and xylan by a combination of pre- and postincubation effects (i.e., an increase in the release of reducing sugars during the pretreatment phase and an increase in the hydrolytic activity of the liquid and solid fractions of the ruminal fluid), which was reflected in a higher rate of fermentation.

Frequency of word-use predicts rates of lexical evolution throughout Indo-European history

Greek speakers say "ovpa", Germans "schwanz'' and the French "queue'' to describe what English speakers call a 'tail', but all of these languages use a related form of 'two' to describe the number after one. Among more than 100 Indo-European languages and dialects, the words for some meanings (such as 'tail') evolve rapidly, being expressed across languages by dozens of unrelated words, while others evolve much more slowly-such as the number 'two', for which all Indo-European language speakers use the same related word-form(1). No general linguistic mechanism has been advanced to explain this striking variation in rates of lexical replacement among meanings. Here we use four large and divergent language corpora (English(2), Spanish(3), Russian(4) and Greek(5)) and a comparative database of 200 fundamental vocabulary meanings in 87 Indo-European languages(6) to show that the frequency with which these words are used in modern language predicts their rate of replacement over thousands of years of Indo-European language evolution. Across all 200 meanings, frequently used words evolve at slower rates and infrequently used words evolve more rapidly. This relationship holds separately and identically across parts of speech for each of the four language corpora, and accounts for approximately 50% of the variation in historical rates of lexical replacement. We propose that the frequency with which specific words are used in everyday language exerts a general and law-like influence on their rates of evolution. Our findings are consistent with social models of word change that emphasize the role of selection, and suggest that owing to the ways that humans use language, some words will evolve slowly and others rapidly across all languages.

Analysis of molecular determinants of affinity and relative efficacy of a series of R- and S-2-(dipropylamino)tetralins at the 5-HT1A serotonin receptor

1 Factors influencing agonist affinity and relative efficacy have been studied for the 5-HT1A serotonin receptor using membranes of CHO cells expressing the human form of the receptor and a series of R-and S-2-(dipropylamino)tetralins (nonhydroxylated and monohydroxylated (5-OH, 6-OH, 7-OH, 8-OH) species). 2 Ligand binding studies were used to determine dissociation constants for agonist binding to the 5HT(1A) receptor: (a) K-i values for agonists were determined in competition versus the binding of the agonist [H-3]-8-OH DPAT. Competition data were all fitted best by a one-binding site model. (b) K-i values for agonists were also determined in competition versus the binding of the antagonist [H-3]-NAD-199. Competition data were all fitted best by a two-binding site model, and agonist affinities for the higher (K-h) and lower affinity (K-1) sites were determined. 3 The ability of the agonists to activate the 5-HT1A receptor was determined using stimulation of [S-35]-GTPgammaS binding. Maximal effects of agonists (E-max) and their potencies (EC50) were determined from concentration/response curves for stimulation of [S-35]-GTPgammaS binding. 4 K-1/K-h determined from ligand binding assays correlated with the relative efficacy (relative Em) of agonists determined in [S-35]-GTPgammaS binding assays. There was also a correlation between K-1/K-h and K-1/EC50 for agonists determined from ligand binding and [S-35]-GTPgammaS binding assays. 5 Simulations of agonist binding and effect data were performed using the Ternary Complex Model in order to assess the use of K-1/K-h for predicting the relative efficacy of agonists. British Journal of Pharmacology (2003) 138, 1129-1139. doi: 10. 1038/sj.bjp.705085.

When school is not enough: new initiatives in intergenerational language transmission in Wales

This paper examines language reproduction in the family in the context of a highly innovative project in Wales, where the Welsh language has been in decline for over a century. Although Welsh-medium schooling has played a pivotal role in slowing and even reversing language shift in recent decades, there is mounting evidence of the dangers of over-reliance on education. The Twf (Growth) Project was established in 2002 with funding from the National Assembly for Wales with the aim of raising awareness of the benefits of bilingualism among parents and prospective parents. Analysis of interviews with the main stakeholders in the project (managers, the Twf project officers, parents, health workers and a range of other partners), publicity materials and observations of project staff at work suggests that the achievements of the project lie in two main areas: the recognition of the need for building strong alliances with professional groups and organisations that work with families with young children; and the development of a marketing strategy appropriate for the target audience. It is argued that the experience of the project will be of interest to those addressing the issue of intergenerational transmission in a range of other minority language settings.

Allosteric effects of antagonists on signalling by the chemokine receptor CCR5

Antagonists of the chemokine receptor, CCRS, may provide important new drugs for the treatment of HIV-1. In this study we have examined the mechanism of action of two functional antagonists of the chemokine receptor CCRS (UK-396,794, UK-438,235) in signalling and internalisation assays using CHO cells expressing CCR5. Both compounds were potent inverse agonists versus agonist-independent [S-3]GTP gamma S binding to membranes of CHO cells expressing CCR5. Both compounds also acted as allosteric inhibitors of CCL5 (RANTES) and CCL8 (MCP-2) -stimulated [S-35]GTP gamma S binding to CHO-CCR5 membranes, reducing the potency and maximal effects of the two chemokines. The data are consistent with effects of the allosteric inhibitors on both the binding and signalling of the chemokines. Both compounds inhibited CCR5 internalisation triggered by chemokines. When CHO-CCR5 cells were treated with either of the two compounds for prolonged periods of time (24 h) an increase (similar to 15%) in cell surface CCRS was detected. (C) 2007 Elsevier Inc. All rights reserved

The human thalamus processes syntactic and semantic language violations

Numerous linguistic operations have been assigned to cortical brain areas, but the contributions of subcortical structures to human language processing are still being discussed. Using simultaneous EEG recordings directly from deep brain structures and the scalp, we show that the human thalamus systematically reacts to syntactic and semantic parameters of auditorily presented language in a temporally interleaved manner in coordination with cortical regions. In contrast, two key structures of the basal ganglia, the globus pallidus internus and the subthalamic nucleus, were not found to be engaged in these processes. We therefore propose that syntactic and semantic language analysis is primarily realized within cortico-thalamic networks, whereas a cohesive basal ganglia network is not involved in these essential operations of language analysis.

Right hemisphere language functions and schizophrenia: the forgotten hemisphere?

This review highlights the importance of right hemisphere language functions for successful social communication and advances the hypothesis that the core deficit in psychosis is a failure of segregation of right from left hemisphere functions. Lesion studies of stroke patients and dichotic listening and functional imaging studies of healthy people have shown that some language functions are mediated by the right hemisphere rather than the left. These functions include discourse planning/comprehension, understanding humour, sarcasm, metaphors and indirect requests, and the generation/comprehension of emotional prosody. Behavioural evidence indicates that patients with typical schizophrenic illnesses perform poorly on tests of these functions, and aspects of these functions are disturbed in schizo-affective and affective psychoses. The higher order language functions mediated by the right hemisphere are essential to an accurate understanding of someone's communicative intent, and the deficits displayed by patients with schizophrenia may make a significant contribution to their social interaction deficits. We outline a bi-hemispheric theory of the neural basis of language that emphasizes the role of the sapiens-specific cerebral torque in determining the four-chambered nature of the human brain in relation to the origins of language and the symptoms of schizophrenia. Future studies of abnormal lateralization of left hemisphere language functions need to take account of the consequences of a failure of lateralization of language functions to the right as well as the left hemisphere.

Autistic symptomatology and language ability in autism spectrum disorder and specific language impairment

Background: Autism spectrum disorders (ASD) and specific language impairment (SLI) are common developmental disorders characterised by deficits in language and communication. The nature of the relationship between them continues to be a matter of debate. This study investigates whether the co-occurrence of ASD and language impairment is associated with differences in severity or pattern of autistic symptomatology or language profile. Methods: Participants (N = 97) were drawn from a total population cohort of 56,946 screened as part of study to ascertain the prevalence of ASD, aged 9 to 14 years. All children received an ICD-10 clinical diagnosis of ASD or No ASD. Children with nonverbal IQ 80 were divided into those with a language impairment (language score of 77 or less) and those without, creating three groups: children with ASD and a language impairment (ALI; N = 41), those with ASD and but no language impairment (ANL; N = 31) and those with language impairment but no ASD (SLI; N = 25). Results: Children with ALI did not show more current autistic symptoms than those with ANL. Children with SLI were well below the threshold for ASD. Their social adaptation was higher than the ASD groups, but still nearly 2 SD below average. In ALI the combination of ASD and language impairment was associated with weaker functional communication and more severe receptive language difficulties than those found in SLI. Receptive and expressive language were equally impaired in ALI, whereas in SLI receptive language was stronger than expressive. Conclusions: Co-occurrence of ASD and language impairment is not associated with increased current autistic symptomatology but appears to be associated with greater impairment in receptive language and functional communication.