Do synergies improve accuracy? A study of speed-accuracy trade-offs during finger force production

We explored possible effects of negative covariation among finger forces in multifinger accurate force production tasks on the classical Fitts's speed-accuracy trade-off. Healthy subjects performed cyclic force changes between pairs of targets ""as quickly and accurately as possible."" Tasks with two force amplitudes and six ratics of force amplitude to target size were performed by each of the four fingers of the right hand and four finger combinations. There was a close to linear relation between movement time and the log-transformed ratio of target amplitude to target size across all finger combinations. There was a close to linear relation between standard deviation of force amplitude and movement time. There were no differences between the performance of either of the two ""radial"" fingers (index and middle) and the multifinger tasks. The ""ulnar"" fingers (little and ring) showed higher indices of variability and longer movement times as compared with both ""radial"" fingers and multifinger combinations. We conclude that potential effects of the negative covariation and also of the task-sharing across a set of fingers are counterbalanced by an increase in individual finger force variability in multifinger tasks as compared with single-finger tasks. The results speak in favor of a feed-forward model of multifinger synergies. They corroborate a hypothesis that multifinger synergies are created not to improve overall accuracy, but to allow the system larger flexibility, for example to deal with unexpected perturbations and concomitant tasks.

Effects of Bilingualism on Multi-Word Production

It has been shown that bilinguals are disadvantaged on some language production tasks when compared to monolinguals. The present study investigated the effects of bilingualism on lexical retrieval in single and multi-word utterances. To this purpose, we tested three groups of 35 participants each (Spanish monolinguals, highly proficient Spanish-Catalan and Catalan-Spanish bilinguals) in two sets of picture naming experiments. In the first one, participants were asked to name black-and-white object drawings by single words. In the second one, participants had to name colored pictures with determiner adjectival noun phrases (NP) like “the red car”. In both sets of experiments, bilinguals were slower than monolinguals, even when naming in their dominant language. We also examined the articulatory durations of both single word and NP productions for this bilingual disadvantage. Furthermore, response onset times and durations of all groups in both experiments were affected by lexical variables of the picture names. These results are consistent with previous studies (Ivanova & Costa, 2008, Gollan et al., 2005) showing a bilingual disadvantage in single word production and extend these findings to multiword-utterances and response durations. They also support the claim that articulatory processes are influenced by lexical variables.

Design and implementation of a production synchronization extension for Microsoft Dynamics AX

In a just-in-time, assemble-to-order production environments the scheduling of material requirements and production tasks - even though difficult - is of paramount importance. Different enterprise resource planning solutions with master scheduling functionality have been created to ease this problem and work as expected unless there is a problem in the material flow. This case-based candidate’s thesis introduces a tool for Microsoft Dynamics AX multisite environment, that can be used by site managers and production coordinators to get an overview of the current open sales order base and prioritize production in the event of material shortouts to avoid part-deliveries.

Factors influencing the use of selected inputs in yam production in Nigeria and Ghana

In West Africa, yam can be an important crop to reduce poverty and hunger if Research and Development measures identify and properly engage its key production factors for enhanced outputs and better income. Data from 1400 households in Ghana and Nigeria were collected in a multistage random sampling survey (and complementary data from 76 farm family fields) with a structured questionnaire and qualitative interview questions. The results showed that yam is produced mainly with crude inputs/technologies to reduce high dependence on labour, seed production and control of pests and diseases. Yam is produced widely with purchased inputs including seed yam and hired labour; chemical fertiliser, herbicide and pesticides are less often used. Analyses of determinants of use of purchased inputs reveal three serious impediments to expansion in yam production: the increasing scarcity and high cost of hired labour, shortage of suitable land and poor farm roads. As employment opportunities for unskilled labour in urban centres are presently expanding, increased yam production will be hard to achieve without labour-saving inputs for at least some of the production tasks, especially seedbed preparation and weeding, and without improvement in infrastructure.

Production and on-line comprehension of definite articles and clitic pronouns by Greek sequential bilingual children and monolingual children with specific language impairment

The present study compared production and on-line comprehension of definite articles and third person direct object clitic pronouns in Greek-speaking typically developing, sequential bilingual (L2-TD) children and monolingual children with specific language impairment (L1-SLI). Twenty Turkish Greek L2-TD children, 16 Greek L1-SLI children, and 31 L1-TD Greek children participated in a production task examining definite articles and clitic pronouns and, in an on-line comprehension task, involving grammatical sentences with definite articles and clitics and sentences with grammatical violations induced by omitted articles and clitics. The results showed that the L2-TD children were sensitive to the grammatical violations despite low production. In contrast, the children with SLI were not sensitive to clitic omission in the on-line task, despite high production. These results support a dissociation between production and on-line comprehension in L2 children and for impaired grammatical representations and lack of automaticity in children with SLI. They also suggest that on-line comprehension tasks may complement production tasks by differentiating between the language profiles of L2-TD children and children with SLI.

Sistemas de fachadas em perfilaria de alumínio, painel compósito em Alucobond e estruturas metálicas

A memória descritiva do estágio transcreve e revela os conhecimentos adquiridos ao longo do curso e aplicados ao longo do estágio, bem como todos aqueles obtidos e aperfeiçoados no estágio, nomeadamente no que espeita a planeamento, controlo de custos, aprovisionamento, preparação dos materiais e elaboração de autos de medição. Para um melhor aprofundamento destes conceitos, foi proposto pela empresa, o acompanhamento técnico de duas obras, contudo, ambas distintas quer ao nível de materiais e execução. Primeiramente, é feita uma pequena apresentação da empresa assim como uma descrição global das duas obras que foram propostas pela empresa, para fazer o acompanhamento técnico ao longo do estágio Apresentados os traços gerais do estágio é realizada uma pequena exposição teórica dos dois principais elementos, alumínio e aço, constituintes dos principais materiais utilizados nas duas obras em acompanhamento, indicando alguns dados sobre o seu modo de produção e caracterização física e mecânica. Nos dois capítulos seguintes faz-se uma descrição dos principais trabalhos realizados em ambas as obras. Na obra da rua Alfredo do Guisado são enunciados todas as tarefas da produção e da preparação em oficina para aplicação em obra de uma fachada ventilada em painel compósito de Alucobond. No que respeita a obra da Caetano Parts é feito o enquadramento do acompanhamento técnico em todas as tarefas desempenhadas pelas oficinas, descrevendo todos os processos envolvidos desde a preparação, aprovisionamento, tratamento e montagem dos diferentes materiais em obra. Por fim, são apresentadas algumas considerações finais do estágio desenvolvido.

Estudo e análise do sequenciamento de tarefas de produção: job shop scheduling

Esta dissertação apresenta um estudo sobre os problemas de sequenciamento de tarefas de produção do tipo job shop scheduling. Os problemas de sequenciamento de tarefas de produção pretendem encontrar a melhor sequência para o processamento de uma lista de tarefas, o instante de início e término de cada tarefa e a afetação de máquinas para as tarefas. Entre estes, encontram-se os problemas com máquinas paralelas, os problemas job shop e flow shop. As medidas de desempenho mais comuns são o makespan (instante de término da execução de todas as tarefas), o tempo de fluxo total, a soma dos atrasos (tardiness), o atraso máximo, o número de tarefas que são completadas após a data limite, entre outros. Num problema do tipo job shop, as tarefas (jobs) consistem num conjunto de operações que têm de ser executadas numa máquina pré-determinada, obedecendo a um determinado sequenciamento com tempos pré-definidos. Estes ambientes permitem diferentes cenários de sequenciamento das tarefas. Normalmente, não são permitidas interrupções no processamento das tarefas (preemption) e pode ainda ser necessário considerar tempos de preparação dependentes da sequência (sequence dependent setup times) ou atribuir pesos (prioridades) diferentes em função da importância da tarefa ou do cliente. Pretende-se o estudo dos modelos matemáticos existentes para várias variantes dos problemas de sequenciamento de tarefas do tipo job shop e a comparação dos resultados das diversas medidas de desempenho da produção. Este trabalho contribui para demonstrar a importância que um bom sequenciamento da produção pode ter na sua eficiência e consequente impacto financeiro.

Tietovirtojen kehittäminen teollisessa valmistusprosessissa

Työn tavoitteena on analysoida ABB Oy:n Indutiokoneet-tulosyksikön tuotantoprosessin loppuosaa tietovirtojen näkökulmasta ja tutkia miten tiedonkulkua tulisi kehittää valmistusprosessin loppupään tehostamiseksi. Teoreettisena viitekehyksessä vertaillaan prosessinkehittämisen koulukuntia jatkuvaa parantamista ja prosessien suunnittelua ja käsitellään prosessin hallintaan ja kehittämiseen tarvittavia tietovirtoja ja niiden käsitteellistämistä sekä prosessinkehitysprojektin vaiheita. Tarkasteltavaa prosessia lähestytään analysoimalla, miten tutkittava osaprosessi toimii tällä hetkellä ja mitä ongelmia prosessin tiedonkulkuun liittyy. Analyysin pohjalta identifioidaan kahdeksan virhettä prosessissa ja virheiden poistamiseksi kehitystoimenpiteet, jotka liittyvät prosessin tekniseen infrastruktuuriin ja tietotekniseen tukeen sekä prosessin henkilöstön ohjeistukseen. Kehitysehdotusten avulla tarkasteltavassa työyksikössä nykyisin suoritettavia, varsinaisia työvaiheita tukevia vaiheita voidaan poistaa, mikä vapauttaa puolipäiväisen työpanoksen muihin tehtäviin ja pakkausprosessin virheiden väheneminen tuo rahallisia säästöjä kuljetuskustannuksissa.

Aspect selection in adult L2 Spanish and the competing systems hypothesis: when pedagogical and linguistic rules conflict.

Native-like use of preterit and imperfect morphology in all contexts by English learners of L2 Spanish is the exception rather than the rule, even for successful learners. Nevertheless, recent research has demonstrated that advanced English learners of L2 Spanish attain a native-like morphosyntactic competence for the preterit/imperfect contrast, as evidenced by their native-like knowledge of associated semantic entailments (Goodin-Mayeda and Rothman 2007, Montrul and Slabakova 2003, Slabakova and Montrul 2003, Rothman and Iverson 2007). In addition to an L2 disassociation of morphology and syntax (e.g., Bruhn de Garavito 2003, Lardiere 1998, 2000, 2005, Prévost and White 1999, 2000, Schwartz 2003), I hypothesize that a system of learned pedagogical rules contributes to target-deviant L2 performance in this domain through the most advanced stages of L2 acquisition via its competition with the generative system. I call this hypothesis the Competing Systems Hypothesis. To test its predictions, I compare and contrast the use of the preterit and imperfect in two production tasks by native, tutored (classroom), and naturalistic learners of L2 Spanish.

Individual differences in early language learning: a study of English learners of French

The present longitudinal study examines the interaction of learner variables (gender, motivation, self-efficacy and first language literacy) and their influence on second language learning outcomes. The study follows English learners of French from Year 5 in primary school (aged 9-10) to the first year in secondary school (Year 7 aged 11-12). Language outcomes were measured by two oral production tasks; a sentence repetition task and a photo description task both of which were administered at three time points. Longitudinal data on learner attitudes and motivation were collected via questionnaires. Teacher assessment data for general first language literacy attainment were also provided. The results show a great deal of variation in learner attitudes and outcomes and that there is a complex relationship between first language literacy, self-efficacy, gender and attainment. For example, in general, girls held more positive attitudes to boys and were more successful. However, the inclusion of first language ability, which explained 30-40% of variation, shows that gender differences in attitudes and outcomes are likely mediated by first language literacy and prior learning experience.

Preserved speech abilities and compensation following prefrontal damage.

Lesions to left frontal cortex in humans produce speech production impairments (nonfluent aphasia). These impairments vary from subject to subject and performance on certain speech production tasks can be relatively preserved in some patients. A possible explanation for preservation of function under these circumstances is that areas outside left prefrontal cortex are used to compensate for the injured brain area. We report here a direct demonstration of preserved language function in a stroke patient (LF1) apparently due to the activation of a compensatory brain pathway. We used functional brain imaging with positron emission tomography (PET) as a basis for this study.

English syllable confusion and imitation in Korean bilingual and monolingual children and adults

In the present study, Korean-English bilingual (KEB) and Korean monolingual (KM) children, between the ages of 8 and 13 years, and KEB adults, ages 18 and older, were examined with one speech perception task, called the Nonsense Syllable Confusion Matrix (NSCM) task (Allen, 2005), and two production tasks, called the Nonsense Syllable Imitation Task (NSIT) and the Nonword Repetition Task (NRT; Dollaghan & Campbell, 1998). The present study examined (a) which English sounds on the NSCM task were identified less well, presumably due to interference from Korean phonology, in bilinguals learning English as a second language (L2) and in monolinguals learning English as a foreign language (FL); (b) which English phonemes on the NSIT were more challenging for bilinguals and monolinguals to produce; (c) whether perception on the NSCM task is related to production on the NSIT, or phonological awareness, as measured by the NRT; and (d) whether perception and production differ in three age-language status groups (i.e., KEB children, KEB adults, and KM children) and in three proficiency subgroups of KEB children (i.e., English-dominant, ED; balanced, BAL; and Korean-dominant, KD). In order to determine English proficiency in each group, language samples were extensively and rigorously analyzed, using software, called Systematic Analysis of Language Transcripts (SALT). Length of samples in complete and intelligible utterances, number of different and total words (NDW and NTW, respectively), speech rate in words per minute (WPM), and number of grammatical errors, mazes, and abandoned utterances were measured and compared among the three initial groups and the three proficiency subgroups. Results of the language sample analysis (LSA) showed significant group differences only between the KEBs and the KM children, but not between the KEB children and adults. Nonetheless, compared to normative means (from a sample length- and age-matched database provided by SALT), the KEB adult group and the KD subgroup produced English at significantly slower speech rates than expected for monolingual, English-speaking counterparts. Two existing models of bilingual speech perception and production—the Speech Learning Model or SLM (Flege, 1987, 1992) and the Perceptual Assimilation Model or PAM (Best, McRoberts, & Sithole, 1988; Best, McRoberts, & Goodell, 2001)—were considered to see if they could account for the perceptual and production patterns evident in the present study. The selected English sounds for stimuli in the NSCM task and the NSIT were 10 consonants, /p, b, k, g, f, θ, s, z, ʧ, ʤ/, and 3 vowels /I, ɛ, æ/, which were used to create 30 nonsense syllables in a consonant-vowel structure. Based on phonetic or phonemic differences between the two languages, English sounds were categorized either as familiar sounds—namely, English sounds that are similar, but not identical, to L1 Korean, including /p, k, s, ʧ, ɛ/—or unfamiliar sounds—namely, English sounds that are new to L1, including /b, g, f, θ, z, ʤ, I, æ/. The results of the NSCM task showed that (a) consonants were perceived correctly more often than vowels, (b) familiar sounds were perceived correctly more often than unfamiliar ones, and (c) familiar consonants were perceived correctly more often than unfamiliar ones across the three age-language status groups and across the three proficiency subgroups; and (d) the KEB children perceived correctly more often than the KEB adults, the KEB children and adults perceived correctly more often than the KM children, and the ED and BAL subgroups perceived correctly more often than the KD subgroup. The results of the NSIT showed (a) consonants were produced more accurately than vowels, and (b) familiar sounds were produced more accurately than unfamiliar ones, across the three age-language status groups. Also, (c) familiar consonants were produced more accurately than unfamiliar ones in the KEB and KM child groups, and (d) unfamiliar vowels were produced more accurately than a familiar one in the KEB child group, but the reverse was true in the KEB adult and KM child groups. The KEB children produced sounds correctly significantly more often than the KM children and the KEB adults, though the percent correct differences were smaller than for perception. Production differences were not found among the three proficiency subgroups. Perception on the NSCM task was compared to production on the NSIT and NRT. Weak positive correlations were found between perception and production (NSIT) for unfamiliar consonants and sounds, whereas a weak negative correlation was found for unfamiliar vowels. Several correlations were significant for perceptual performance on the NSCM task and overall production performance on the NRT: for unfamiliar consonants, unfamiliar vowels, unfamiliar sounds, consonants, vowels, and overall performance on the NSCM task. Nonetheless, no significant correlation was found between production on the NSIT and NRT. Evidently these are two very different production tasks, where immediate imitation of single syllables on the NSIT results in high performance for all groups. Findings of the present study suggest that (a) perception and production of L2 consonants differ from those of vowels; (b) perception and production of L2 sounds involve an interaction of sound type and familiarity; (c) a weak relation exists between perception and production performance for unfamiliar sounds; and (d) L2 experience generally predicts perceptual and production performance. The present study yields several conclusions. The first is that familiarity of sounds is an important influence on L2 learning, as claimed by both SLM and PAM. In the present study, familiar sounds were perceived and produced correctly more often than unfamiliar ones in most cases, in keeping with PAM, though experienced L2 learners (i.e., the KEB children) produced unfamiliar vowels better than familiar ones, in keeping with SLM. Nonetheless, the second conclusion is that neither SLM nor PAM consistently and thoroughly explains the results of the present study. This is because both theories assume that the influence of L1 on the perception of L2 consonants and vowels works in the same way as for production of them. The third and fourth conclusions are two proposed arguments: that perception and production of consonants are different than for vowels, and that sound type interacts with familiarity and L2 experience. These two arguments can best explain the current findings. These findings may help us to develop educational curricula for bilingual individuals listening to and articulating English. Further, the extensive analysis of spontaneous speech in the present study should contribute to the specification of parameters for normal language development and function in Korean-English bilingual children and adults.

Analyse de l'effet d'âge et du sexe sur l'utilisation des symboles graphiques

La suppléance à la communication (SC) est un moyen qui permet aux personnes qui ne peuvent pas communiquer par la parole de transmettre des informations à leur environnement et d'interagir de manière fonctionnelle avec lui. Le développement de la SC connaît des avancées importantes depuis quelques années, surtout avec l'avènement de nouvelles technologies. Toujours est-il qu'une compréhension plus approfondie des mécanismes qui sous-tendent l'utilisation de la SC reste primordiale. De plus, les relations qui existent entre l'utilisation du langage oral et de symboles graphiques sont peu explorées à ce jour. La présente étude fait partie d'un projet plus large visant donc à mieux explorer la nature des compétences nécessaires à une utilisation optimale de symboles graphiques dans la SC. Ainsi, et afin de mieux comprendre cette relation entre le langage oral et l'utilisation de symboles graphiques aussi bien en production qu'en compréhension, ainsi que pour mieux explorer l'effet d'âge et de genre, nous avons recruté 79 enfants (37 filles et 42 garçons), âgés entre 4;1 ans et 9;11ans, et qui présentent un développement typique du langage. L'étude du développement typique nous permet d'étudier certaines habiletés qui peuvent être difficiles à évaluer chez des enfants présentant des déficits sévères. Les sujets ont été répartis en 3 groupes selon leur âge: groupe 4-5 ans (n=26), groupe 6-7 ans (n=35) et groupe 8-9 ans (n=18). Plusieurs tâches ont été crées; celles-ci comprenaient des tâches de compréhension et de production, avec comme matériel des symboles graphiques, des objets ou des mots, qui étaient répartis au sein d'énoncés formés de trois, quatre, six ou huit éléments. Les résultats montrent tout d'abord deux profils distincts: chez les jeunes enfants, on observe une meilleure performance aux tâches d'interprétation par rapport aux tâches de production. Cependant, cette différence n'est plus évidente pour les groupes des plus âgés, et la distinction principale se situe alors au niveau de la différence de performance entre les tâches orales et les tâches symboliques au profit des premières. Par ailleurs, et conformément aux observations sur le développement du langage oral, la performance des filles est supérieure à celle des garçons à toutes les tâches, et cette différence semble disparaître avec l'âge. Enfin, nos résultats ont permis de montrer une amélioration plus marquée de la maîtrise du langage oral avec l'âge par comparaison à la maîtrise du traitement du symbole graphique. Par contre, l'interprétation et la production semblent être maîtrisées de manière similaire. Notre étude vient appuyer certains résultats rapportés dans la littérature, ainsi qu'élargir les connaissances surtout au niveau des liens qui existent entre la production et l'interprétation orale et symbolique en fonction de l'âge et du genre.

Analyse de l'effet d'âge et du sexe sur l'utilisation des symboles graphiques

La suppléance à la communication (SC) est un moyen qui permet aux personnes qui ne peuvent pas communiquer par la parole de transmettre des informations à leur environnement et d'interagir de manière fonctionnelle avec lui. Le développement de la SC connaît des avancées importantes depuis quelques années, surtout avec l'avènement de nouvelles technologies. Toujours est-il qu'une compréhension plus approfondie des mécanismes qui sous-tendent l'utilisation de la SC reste primordiale. De plus, les relations qui existent entre l'utilisation du langage oral et de symboles graphiques sont peu explorées à ce jour. La présente étude fait partie d'un projet plus large visant donc à mieux explorer la nature des compétences nécessaires à une utilisation optimale de symboles graphiques dans la SC. Ainsi, et afin de mieux comprendre cette relation entre le langage oral et l'utilisation de symboles graphiques aussi bien en production qu'en compréhension, ainsi que pour mieux explorer l'effet d'âge et de genre, nous avons recruté 79 enfants (37 filles et 42 garçons), âgés entre 4;1 ans et 9;11ans, et qui présentent un développement typique du langage. L'étude du développement typique nous permet d'étudier certaines habiletés qui peuvent être difficiles à évaluer chez des enfants présentant des déficits sévères. Les sujets ont été répartis en 3 groupes selon leur âge: groupe 4-5 ans (n=26), groupe 6-7 ans (n=35) et groupe 8-9 ans (n=18). Plusieurs tâches ont été crées; celles-ci comprenaient des tâches de compréhension et de production, avec comme matériel des symboles graphiques, des objets ou des mots, qui étaient répartis au sein d'énoncés formés de trois, quatre, six ou huit éléments. Les résultats montrent tout d'abord deux profils distincts: chez les jeunes enfants, on observe une meilleure performance aux tâches d'interprétation par rapport aux tâches de production. Cependant, cette différence n'est plus évidente pour les groupes des plus âgés, et la distinction principale se situe alors au niveau de la différence de performance entre les tâches orales et les tâches symboliques au profit des premières. Par ailleurs, et conformément aux observations sur le développement du langage oral, la performance des filles est supérieure à celle des garçons à toutes les tâches, et cette différence semble disparaître avec l'âge. Enfin, nos résultats ont permis de montrer une amélioration plus marquée de la maîtrise du langage oral avec l'âge par comparaison à la maîtrise du traitement du symbole graphique. Par contre, l'interprétation et la production semblent être maîtrisées de manière similaire. Notre étude vient appuyer certains résultats rapportés dans la littérature, ainsi qu'élargir les connaissances surtout au niveau des liens qui existent entre la production et l'interprétation orale et symbolique en fonction de l'âge et du genre.

Lateralization of speech production using verbal/manual dual tasks: meta-analysis of sex differences and practice effects

The present paper reviews the findings of 30 years of verbal/manual dual task studies, the method most commonly used to assess lateralization of speech production in non-clinical samples. Meta-analysis of 64 results revealed that both the type of manual task used and the nature of practice that is given influence the size of the laterality effect. A meta-analysis of 36 results examining the effect size of sex differences in estimate,, of lateralization of speech production indicated that males appear to show, slightly larger laterality effects than females. (C) 2002 Elsevier Science Ltd. All rights reserved.