Force Control Strategy of Five-Digit Precision Grasping With Aligned and Unaligned Configurations

Objective To investigate the digit force control during a five-digit precision grasp in aligned (AG) and unaligned grasping (UG) configurations. Background The effects of various cylindrical handles for tools on power grasp performance have been previously investigated. However, there is little information on force control strategy of precision grasp to fit various grasping configurations. Method Twenty healthy young adults were recruited to perform a lift-hold-lower task. The AG and UG configurations on a cylindrical simulator with force transducers were adjusted for each individual. The applied force and moment, the force variability during holding, and force correlations between thumb and each finger were measured. Result No differences in applied force, force correlation, repeatability, and variability were found between configurations. However, the moments applied in UG were significantly larger than those in AG. Conclusion The force control during precision grasp did not change significantly across AG and UG except for the digit moment. The simulator is controlled efficiently with large moment during UG, which is thus the optimal configuration for precision grasping with a cylindrical handle. Further research should consider the effects of task type and handle design on force control, especially for individuals with hand disorders. Application To design the handle of specific tool, one should consider the appropriate configuration according to the task requirements of precision grasping to reduce the risk of accumulating extra loads on digits with a cylindrical handle.

An fMRI Study Using a Combined Task of Interval Discrimination and Oddball Could Reveal Common Brain Circuits of Cognitive Change

Recent functional neuroimaging studies suggest that the brain networks responsible for time processing are involved during other cognitive processes, leading to a hypothesis that time-related processing is needed to perform a range of tasks across various cognitive functions. To examine this hypothesis, we analyze whether, in healthy subjects, the brain structures activated or deactivated during performance of timing and oddball-detection type tasks coincide. To this end, we conducted two independent signed differential mapping (SDM) meta-analyses of functional magnetic resonance imaging (fMRI) studies assessing the cerebral generators of the responses elicited by tasks based on timing and oddball-detection paradigms. Finally, we undertook a multimodal meta-analysis to detect brain regions common to the findings of the two previous meta-analyses. We found that healthy subjects showed significant activation in cortical areas related to timing and salience networks. The patterns of activation and deactivation corresponding to each task type partially coincided. We hypothesize that there exists a time and change-detection network that serves as a common underlying resource used in a broad range of cognitive processes.

Engaging L2 Learners in Information-gap Tasks: How Task Type and Topic Familiarity Affect Learner Engagement

This study examines four learner engagement dimensions (behavioural, cognitive, emotional and social) in pedagogical task performance and provides insights into the effects of two task types (information-seeking and direction-giving) and topic familiarity on learner engagement in a semester-long English course. A total of 28 foreign language learners engaged in eight interactive tasks, and all played the roles of both information-receiver and information-provider alternately under familiar and unfamiliar conditions. Seven measures of engagement and an open-ended questionnaire were employed to understand the learners’ engagement in the tasks and their emotional responses to them. The results revealed that the information-providers produced more words and also spent more time on information-seeking tasks wherein they would exchange information than on direction-giving ones that required them to ask for and provide instructions or directions. This was the case for topics they were unfamiliar with; however, when they were faced with familiar topics, they produced significantly more words, spent more time, and spoke more elaboratively in direction-giving tasks. The information-seeking tasks elicited positive emotions, but the direction-giving tasks yielded mixed feelings, attaching positive emotions to familiar tasks but negative ones to unfamiliar tasks. The pedagogical implications of these findings are discussed.

The Efficacy of Computer-Mediated Feedback in Improving L2 Speaking: A Systematic Review

Recent trends in computer-mediated communication (CMC) have led to a proliferation of studies investigating the effect of computer-mediated feedback (CMF). The present systematic review aimed to explore the role of linguistic, contextual, and individual factors in mediating the impact of CMF on second language (L2) speaking performance. A literature search located 16 relevant empirical studies for the final analysis. Each study was coded for linguistic, contextual, and individual characteristics. First, CMF was theoretically conceptualized as an instructional input, a dialogic process, and an internal process based on theoretical underpinnings. Correspondingly, CMF was analyzed under the influence of 1) linguistic factors including feedback type, the linguistic focus of CMF, and the timing of CMF, 2) contextual factors including the feedback source and the task type, and 3) individual factors including individual differences and learners’ proficiency levels. The implication of the study was twofold. Theoretically, this study not only provided a multi-dimension view towards the effect of CMF in developing L2 oral proficiency but also shed new light on the interrelations between these identified factors. Pedagogically, teachers were encouraged to take advantage of CMC technologies to enhance the effectiveness of CMF as well as considering learners’ uniqueness. Suggestions for future research were also provided.

Task-independent Recognition of Communication Skills in Group Interaction Using Time-series Modeling

Case studies of group discussions are considered an effective way to assess communication skills (CS). This method can help researchers evaluate participants’ engagement with each other in a specific realistic context. In this article, multimodal analysis was performed to estimate CS indices using a three-task-type group discussion dataset, the MATRICS corpus. The current research investigated the effectiveness of engaging both static and time-series modeling, especially in task-independent settings. This investigation aimed to understand three main points: first, the effectiveness of time-series modeling compared to nonsequential modeling; second, multimodal analysis in a task-independent setting; and third, important differences to consider when dealing with task-dependent and task-independent settings, specifically in terms of modalities and prediction models. Several modalities were extracted (e.g., acoustics, speaking turns, linguistic-related movement, dialog tags, head motions, and face feature sets) for inferring the CS indices as a regression task. Three predictive models, including support vector regression (SVR), long short-term memory (LSTM), and an enhanced time-series model (an LSTM model with a combination of static and time-series features), were taken into account in this study. Our evaluation was conducted by using the R 2 score in a cross-validation scheme. The experimental results suggested that time-series modeling can improve the performance of multimodal analysis significantly in the task-dependent setting (with the best R 2 = 0.797 for the total CS index), with word2vec being the most prominent feature. Unfortunately, highly context-related features did not fit well with the task-independent setting. Thus, we propose an enhanced LSTM model for dealing with task-independent settings, and we successfully obtained better performance with the enhanced model than with the conventional SVR and LSTM models (the best R 2 = 0.602 for the total CS index). In other words, our study shows that a particular time-series modeling can outperform traditional nonsequential modeling for automatically estimating the CS indices of a participant in a group discussion with regard to task dependency.

Vocabulary usage among Asian EFL learners during speech: a corpus-based quantitative analysis of the effects of L1 type, L2 proficiency and task type

PurposeUsing a newly compiled corpus module consisting of utterances from Asian learners during L2 English interviews, this study examined how Asian EFL learners' L1s (Chinese, Indonesian, Japanese, Korean, Taiwanese and Thai), their L2 proficiency levels (A2, B1 low, B1 upper and B2+) and speech task types (picture descriptions, roleplays and QA-based conversations) affected four aspects of vocabulary usage (number of tokens, standardized type/token ratio, mean word length and mean sentence length).Design/methodology/approachFour aspects concern speech fluency, lexical richness, lexical complexity and structural complexity, respectively.FindingsSubsequent corpus-based quantitative data analyses revealed that (1) learner/native speaker differences existed during the conversation and roleplay tasks in terms of the number of tokens, type/token ratio and sentence length; (2) an L1 group effect existed in all three task types in terms of the number of tokens and sentence length; (3) an L2 proficiency effect existed in all three task types in terms of the number of tokens, type-token ratio and sentence length; and (4) the usage of high-frequency vocabulary was influenced more strongly by the task type and it was classified into four types: Type A vocabulary for grammar control, Type B vocabulary for speech maintenance, Type C vocabulary for negotiation and persuasion and Type D vocabulary for novice learners.Originality/valueThese findings provide clues for better understanding L2 English vocabulary usage among Asian learners during speech.

Cross-Task Consistency of Electroencephalography-Based Mental Workload Indicators: Comparisons Between Power Spectral Density and Task-Irrelevant Auditory Event-Related Potentials

Mental workload (MWL) estimators based on ongoing electroencephalography (EEG) and event-related potentials (ERPs) have shown great potentials to build adaptive aiding systems for human–machine systems by estimating MWL in real time. However, extracting EEG features which are consistent in indicating MWL across different tasks is still one of the critical challenges. This study attempts to compare the cross-task consistency in indexing MWL variations between two commonly used EEG-based MWL indicators, power spectral density (PSD) of ongoing EEG and task-irrelevant auditory ERPs (tir-aERPs). The verbal N-back and the multi-attribute task battery (MATB), both with two difficulty levels, were employed in the experiment, along with task-irrelevant auditory probes. EEG was recorded from 17 subjects when they were performing the tasks. The tir-aERPs elicited by the auditory probes and the relative PSDs of ongoing EEG between two consecutive auditory probes were extracted and statistically analyzed to reveal the effects of MWL and task type. Discriminant analysis and support vector machine were employed to examine the generalization of tir-aERP and PSD features in indexing MWL variations across different tasks. The results showed that the amplitudes of tir-aERP components, N1, early P3a, late P3a, and the reorienting negativity, significantly decreased with the increasing MWL in both N-back and MATB. Task type had no obvious influence on the amplitudes and topological layout of the MWL-sensitive tir-aERP features. The relative PSDs in θ, α, and low β bands were also sensitive to MWL variations. However, the MWL-sensitive PSD features and their topological patterns were significantly affected by task type. The cross-task classification results based on tir-aERP features also significantly outperformed the PSD features. These results suggest that the tir-aERPs should be potentially more consistent MWL indicators across very different task types when compared to PSD. The current study may provide new insights to our understanding of the common and distinctive neuropsychological essences of MWL across different tasks.

Aspects of New Zealand English Intonation and Its Meanings: an Experimental Investigation of Forms and Contrasts

<p>The first aim of this thesis was to examine the form of New Zealand English intonation. The results of the first series of experiments illustrated several distinctive features of NZE intonation and the preferential tonal use within this language variety. The results from the first experiment suggests that NZE intonation can be characterised as having a narrow pitch range within the phrase and a wide pitch range at the end of the phrase in relation to British English. The findings in the second analysis illustrate that tonal composition, not sentence type affects the pitch range that NZE speaker uses. In addition to pitch range preferences, NZE speakers were also found to prefer an H*L-L% nuclear tonal composition on statements and an L*L-H% for two types of questions when conversational cues were not required by the task type. The second aim of the thesis was to define the tonal features which may adequately describe the semantic contrasts used in this variety. Five experiments were carried out with this aim in mind. The results revealed that NZE listeners use the height of pitch target values when interpreting the meaning of intonation and that the heights of three tonal constituents would be useful in notating the semantic contrasts in this language variety. First, the pitch accent target is used in this variety to indicate speaker involvement, whereby higher (H*) or later (L+H*) pitch accent targets indicate a greater degree of involvement than lower (L*) or earlier targets (H*), respectively. This claim was supported by a production experiment (Chapter 5) in which speakers were asked to convey contrasting meanings on identical utterances. The results were such that higher and later pitch peaks were produced to convey concern, emphasis and an impressed attitude, while lower and earlier pitch accent peaks indicated an absence of these three meanings. Further support for this claim was provided in a perception experiment (Chapter 7), which investigated how listeners interpret conversational markers indicating discourse completeness. The results show that NZE listeners interpret higher H* targets as indicating speaker involvement and, subsequently, listener-oriented turn cues. However, a non-emphatic H*, or a high pitch accent which is lower in pitch than a preceding high pitch accent, does not convey such cues. Second, the boundary target is used to contrast continuation with high phrase-final targets and finality with low phrase-final targets in NZE. This assertion was supported by a perception experiment (Chapter 6) which examined categorical boundaries determined by the boundary tone height. The results suggest that there is at least one categorical boundary at the IP-Final position, which is marked by the pitch movement to the boundary target from the preceding H*. In addition, the semantic contrast of the boundary target height was illustrated in two experiments. First, a production experiment (Chapter 5) illustrated how NZE speakers indicate conversational continuation cues and concern with high boundaries whereas low boundaries indicated conversational cessation cues and a lack of concern. A separate perception experiment (Chapter 7) showed that NZE listeners interpret higher boundary targets as speaker continuation cues and listener-oriented speaking cues whereas lower boundary targets again indicated conversational cessation cues for the speaker and to the listener. Third, the phrase accent may prove useful in distinguishing a further semantic contrast used in this language variety, with a level pitch movement from H* to the IP-Final boundary target categorised with the H% stimuli (suggested in Chapter 6) while the distinction between H-L% and L-L% may be best defined as a pitch movement which does not fall to the F0 minimum and a movement which does fall to this low value (Chapter 5). Although the existence of a phrase accent could not be proved in this thesis, the results illustrate support for this tonal feature.</p>

Stress and the Cardiovascular System

<p>The research reported in this thesis is primarily concerned with systemic arterial pulse transit time (PTT) which is of physiological significance because it is the most appropriate indicator of arterial compliance, the primary determinant of cardiac load, PTT acceleration or deceleration being associated with an increase or decrease in cardiac load respectively. Initially, PTT was investigated in the context of active/passive coping. Obrist, et al., (1978) proposed that active coping is generated by tasks of moderate difficulty and is characterized by large, sustained cardiac accelerations. Interbeat interval (IBI) was measured as the reference response for active/passive coping. The assumption is that active coping is the behavioural state which provides the link between psychological stress and hypertension. However, contemporary cardiovascular physiologists put more emphasis on arterial compliance than IBI because it is not only significant in essential hypertension, but is also a critical determinant of circulation efficiency in health and disease. In Experiment 1 men and women completed mental arithmetic, problem solving, reaction time and personal tempo (voluntary button pressing). Acceleratory and deceleratory PTT changes were found during all tasks; IBI changes were predominantly acceleratory and their magnitude was determined by task difficulty. In Experiment 2 subjects completed problem solving tasks at two levels of difficulty. The results confirmed that unexplained directional variability characterized PTT changes and acceleration characterized IBI changes. It was hypothesized that subject state could be a determinant of PTT response direction. In Experiment 3 the State-Trait Anxiety Inventory, the Stress Arousal Checklist, the Eysenck Personality Inventory and the Jenkins Activity Survey were administered before problem solving at three levels of difficulty and personal tempo were completed. PTT directional variability was not accounted for by any of the measures used. IBI changes were again acceleratory and their magnitude was determined by task difficulty. Two extensions of the active/passive coping hypothesis were proposed: 1) that task difficulty and magnitude of IBI change are related along a continuum of behavioural coping; 2) that task type, not difficulty, determines the frequency of IBI acceleration. The effect of task contingency on IBI change was identified as requiring more detailed investigation. It was further hypothesized that relative subject state as measured by a change in resting IBI (Malmo, 1959) could predict the direction of PTT change during task. In Experiment 4 subjects completed all tasks from Experiment 3 in both parts of an extended experimental session. Half the subjects ingested caffeine. IBI decelerated during baseline from part 1 to part 2 and deceleratory PTT changes dominated task responding in part 2. However, a caffeine-induced deceleration in IBI across baselines was not associated with deceleratory PTT change, and directional variability continued to characterize PTT changes. In order to eliminate the directional variability of PTT changes during tasks a further experiment was undertaken which manipulated relative behavioural state prior to task by informing subjects on their first attendance at the laboratory that they would be required to perform a demanding problem solving task on their fifth attendance. From sessions 1 to 4 subjects attended the laboratory for short rest periods only during which cardiovascular activity was recorded. On the fifth session subjects also completed a task. In that experiment (Experiment 5), IBI acceleration over multiple session baselines in anticipation of a task was associated with uniformly acceleratory PTT changes during tasks, supporting the hypothesis that subject initial state is an important determinant of the direction of PTT change, and hence in whether cardiac load increases or decreases under stress.</p>