On the incremental learning and recognition of the pattern of movement of multiple labelled objects in dynamic scenes

In this paper we discuss combining incremental learning and incremental recognition to classify patterns consisting of multiple objects, each represented by multiple spatio-temporal features. Importantly the technique allows for ambiguity in terms of the positions of the start and finish of the pattern. This involves a progressive classification which considers the data at each time instance in the query and thus provides a probable answer before all the query information becomes available. We present two methods that combine incremental learning and incremental recognition: a time instance method and an overall best match method.

Visual perception of movement kinematics and the acquisition of "action prototypes"

Recognizing a class of movements as belonging to a "nominal" action category, such as walking, running, or throwing, is a fundamental human ability. Three experiments were undertaken to test the hypothesis that common ("prototypical") features of moving displays could be learned by observation. Participants viewed moving stick-figure displays resembling forearm flexion movements in the saggital plane. Four displays (presentation displays) were first presented in which one or more movement dimensions were combined with 2 respective cues: direction (up, down), speed (fast, slow), and extent (long, short). Eight test displays were then shown, and the observer indicated whether each test display was like or unlike those previously seen. The results showed that without corrective feedback, a single cue (e.g., up or down) could be correctly recognized, on average, with the proportion correct between .66 and .87. When two cues were manipulated (e.g., up and slow), recognition accuracy remained high, ranging between .72 and .89. Three-cue displays were also easily identified. These results provide the first empirical demonstration of action-prototype learning for categories of human action and show how apparently complex kinematic patterns can be categorized in terms of common features or cues. It was also shown that probability of correct recognition of kinematic properties was reduced when the set of 4 presentation displays were more variable with respect to their shared kinematic property, such as speed or amplitude. Finally, while not conclusive, the results (from 2 of the 3 experiments) did suggest that similarity (or "likeness") with respect to a common kinematic property (or properties) is more easily recognized than dissimilarity.

Internal representation of movement in children with developmental coordination disorder : a mental rotation task

Recent studies show that children with developmental coordination disorder (DCD) have difficulties in generating an accurate visuospatial representation of an intended action, which are shown by deficits in motor imagery. This study sought to test this hypothesis further using a mental rotation paradigm. It was predicted that children with DCD would not conform to the typical pattern of responding when required to imagine movement of their limbs. Participants included 16 children with DCD and 18 control children; mean age for the DCD group was 10 years 4 months, and for controls 10 years. The task required children to judge the handedness of single-hand images that were presented at angles between 0° and 180° at 45° intervals in either direction. Results were broadly consistent with the hypothesis above. Responses of the control children conformed to the typical pattern of mental rotation: a moderate trade-off between response time and angle of rotation. The response pattern for the DCD group was less typical, with a small trade-off function. Response accuracy did not differ between groups. It was suggested that children with DCD, unlike controls, do not automatically enlist motor imagery when performing mental rotation, but rely on an alternative object-based strategy that preserves speed and accuracy. This occurs because these children manifest a reduced ability to make imagined transformations from an egocentric or first-person perspective.

A simplified stroke rehabilitation assessment of movement instrument

Background and Purpose. An efficient, reliable, and valid instrument for assessing motor function in patients with stroke is needed by both clinicians and researchers. To improve administration efficiency, we applied the multidimensional Rasch model to the 30-item, 3-subscale Stroke Rehabilitation Assessment of Movement (STREAM) instrument to produce a concise, reliable, and valid instrument (simplified STREAM [S-STREAM]) for measuring motor function in patients with stroke. Subjects and Methods. The STREAM (consisting of 3 subscales: upper-limb movements, lower-limb movements, and mobility) was administered to 351 subjects with first stroke occurrence and a median time after stroke of 19.5 months. The unidimensionality of each subscale of the STREAM first was verified with unidimensional Rasch analysis. Each subscale of the STREAM then was simplified by deleting redundant items on the basis of expert opinion and the results of the Rasch analysis. The Rasch reliability of the S-STREAM and the concurrent validity of the S-STREAM with the STREAM were examined with multidimensional Rasch analysis and the intraclass correlation coefficient (ICC), respectively. Results. After deleting the items that did not fit the Rasch model, we found that the 8-item upper-limb movement subscale, the 9-item lower-limb movement subscale, and the 10-item mobility subscale assessed single, unidimensional upper-limb movements, lower-limb movements, and mobility, respectively. We selected 5 items from each subscale to construct the S-STREAM and found that the reliability of each subscale of the resulting simplified instrument was high (Rasch reliability coefficients of [greater than or equal to] .91). The agreement between the subscale scores (Rasch estimates) of the S-STREAM and those of the STREAM was excellent (ICC of [greater than or equal to] .99, with a lower limit for the 95% confidence interval of [greater than or equal to] .985), indicating good concurrent validity of the S-STREAM with the STREAM. Discussion and Conclusion. The S-STREAM demonstrates high Rasch reliability, unidimensionality, and concurrent validity with the STREAM in patients with stroke. Furthermore, the S-STREAM is efficient to administer, as it consists of only half the number of items in the original STREAM. Additional studies to examine other psychometric properties (eg, predictive validity and responsiveness) of the S-STREAM or its psychometric properties in various recovery stages after stroke are needed to further establish its utility in both clinical and research settings.

Design of linear functional observers for time-delay systems of the neutral-type

This paper presents the design of reduced-order linear functional observers for a class of linear time-delay systems of the neutral-type. The type of the observer proposed in this paper is without internal delay and its order is the same as the number of linear functions to be estimated. First, conditions for the existence of the reduced-order functional observers that are capable of asymptotically estimating any given function of the state vector are derived. Then, based on the newly derived existence conditions, a procedure is given for the determination of the observer parameters. The results derived in this paper include a range of linear systems and extend some existing results of linear functional observers to linear neutral delay systems. A numerical example is given to illustrate the design procedure.

Exhausting dance : performance and the politics of movement, by Andre Lepecki

The article reviews the book "Exhausting Dance: Performance and the Politics of Movement," by Andre Lepecki.

Applications and prototype for systems of systems swarm robotics

In order to develop a robotic system of systems the robotic platforms must be designed and built. For this to happen, the type of application involved should be clear. Swarm robots need to be self contained and powered. They must also be self governing. Here the authors examine various applications and a prototype robot that may be useful in these scenarios.

What is a presentational media regime? The contemporary breakdown in systems of representation

Foundational to both the operation and legitimation of our traditional media is the idea of representation: in some sense the images of television, the sounds of radio, the narratives of film, and the various public personalities stand in or in place of ourselves. Likewise our contemporary political system function as an elaborate representational system, where regions, "seats", electorates, the nation, and the nationstate are represented by individuals, parties and symbols. Although, there are differences between and among modern nation-states as clearly different political and cultural agendas are at play, the interplay of contemporary media, culture and politics has produced what can be called a 'representational regime' that more or less operates globally, albeit fragmented into national and regional groupings.

This paper explores the initial stages in the breakdown of this system of representation that has allowed a certain organization of culture and politics to expand and develop over the last two centuries. It acknowledges that central to this regime is something Nick Couldry has identified as "the myth of the mediated centre" (Couldry, 2003). What the paper argues, and therefore differs from Couldry's conclusion, is that there are cracks in the glue that holds the system together and they are emerging in the uses of new media. Through an exploration of presentational media - that is, media that is more involved with the presentation of the self for public/private and networked consumption than traditional media's effort to embody their audience in its narratives - the paper reaches for conclusions that identify a more elaborate legitimation crisis looming in our political and cultural worlds.

Metal catalyzed oxidation of tyrosine residues by different oxidation systems of copper/hydrogen peroxide

Metal-catalysed oxidation (MCO) reactions result in the formation of reactive oxygen species (ROS) in biological systems. These ROS cause oxidative stress that contributes to a number of pathological processes leading to a variety of diseases. Tyrosine is one residue that is very susceptible to oxidative modification and the formation of dityrosine (DT) and 3,4-dihydroxyphenylalanine (DOPA) have been widely reported in a number of diseases. However, the mechanisms of MCO of tyrosine in biological systems are poorly understood and require further investigation. In this study we investigated the mechanism of DT and DOPA formation by MCO using N-acetyl tyrosine ethyl ester as a model for tyrosine in proteins and peptides. The results showed that DT formation could be observed upon Cu²⁺/H₂O₂ oxidation at pH 7.4. Our results indicate that it is unlikely to be via Fenton chemistry since Cu⁺/H₂O₂ oxidative conditions did not lead to the formation of DT.

Assessment of movement participation for children with developmental coordination disorders

The Caregiver Assessment of Movement Participation was developed to identify children of 5-10 years old for movement participation difficulties in home contexts. Its psychometric properties were investigated including its usefulness as a screening instrument using both classical test theory methods and Rasch analysis. Results confirmed its validity and reliability.

Visual discrimination and reproduction of movement by individuals with an intellectual disability

This study investigates the capacity of individuals with an intellectual disability to make accurate discriminations of computer-generated displays and also to reproduce the characteristics of those displays. The findings suggest that the learning of everyday motor skills in this population may be hampered by difficulties in visually perceiving important characteristics of the demonstration. Procedures, employed for teaching these skills to intellectually disabled, are being reassessed in the light of these findings.

Screening children with developmental coordination disorder : the development of the caregiver assessment of movement participation

This study investigated the psychometric properties of the Caregiver Assessment of Movement Participation (CAMP), which was developed to measure and identify children with movement participation problems in home contexts. The test-retest reliability, as well as the concurrent and contrast-group validity of the 35-item parent-proxy CAMP, was examined on 312 children aged 5 to 8 years using intraclass correlation, factor analysis, and the Rasch model. Initial findings on the CAMP appeared to support its validity. Testing on other properties from a practical perspective, such as finding the best rating scale structure and cutpoints, are recommended before using the instrument for child health surveillance screening.

Psychometric properties of the caregiver assessment of movement participation scale for screening children with development coordination disorders

Using Rasch analysis, the psychometric properties of a newly developed 35-item parent-proxy instrument, the Caregiver Assessment of Movement Participation (CAMP), designed to measure movement participation problems in children with Developmental Coordination Disorder, were examined. The CAMP was administered to 465 school children aged 5–10 years. Thirty of the 35 items were retained as they had acceptable infit and outfit statistics. Item separation (7.48) and child separation (3.16) were good; moreover, the CAMP had excellent reliability (Reliability Index for item = 0.98; Person = 0.91). Principal components analysis of item residuals confirmed the unidimensionality of the instrument. Based on category probability statistics, the original five-point scale was collapsed into a four-point scale. The item threshold calibration of the CAMP with the Movement Assessment Battery for Children Test was computed. The results indicated that a CAMP total score of 75 is the optimal cut-off point for identifying children at risk of movement problems.