Nominal Task Research Articles

A Semi-Infinite Programming Approach to Preoperative Planning of Robotic Cardiac Surgery Under Geometric Uncertainty

In this paper, a computational framework for patient-specific preoperative planning of Robotics-Assisted Minimally Invasive Cardiac Surgery (RAMICS) is presented. It is expected that preoperative planning of RAMICS will improve the success rate by considering robot kinematics, patient-specific thoracic anatomy, and procedure-specific intraoperative conditions. Given the significant anatomical features localized in the preoperative computed tomography images of a patients thorax, port locations and robot orientations (with respect to the patients body coordinate frame) are determined to optimize qualities such as dexterity, reachability, tool approach angles and maneuverability. To address intraoperative geometric uncertainty, the problem is formulated as a Generalized Semi-Infinite Program (GSIP) with a convex lower-level problem to seek a plan that is less sensitive to geometric uncertainty in the neighborhood of surgical targets. It is demonstrated that with a proper formulation of the problem, the GSIP can be replaced by a tractable constrained nonlinear program that uses a multi-criteria objective function to balance between the nominal task performance and robustness to collisions and joint limit violations. Finally, performance of the proposed formulation is demonstrated by a comparison between the plans generated by the algorithm and those recommended by an experienced surgeon for several case studies.

Overload problem research on aperiodic real-time tasks

In this paper, a novel scheduling mechanism is proposed to handle the real-time overload problem by maximizing the cumulative values of three types of tasks: the soft, the hard and the imprecise tasks. The simulation results show that the performance of our presented mechanism in this paper is greatly improved, much better than that of the other three mechanisms: earliest deadline first (EDF), highest value first (HVF) and highest density first (HDF), under the same conditions of all nominal loads and task type proportions.

Determining the Optimal Challenge Point for Motor Skill Learning in Adults With Moderately Severe Parkinson's Disease

Objective. To test the predictions of the Challenge Point Framework (CPF) for motor learning in individuals with Parkinson's disease (PD) by manipulating nominal task difficulty and conditions of practice. Methods. Twenty adults with PD and 20 nondisabled controls practiced 3 variations of a laboratory-based goal-directed arm movement over 2 days. A between-group (PD, nondisabled) 2-factor design compared 2 levels of nominal task difficulty (low, high) and 2 levels of practice condition (low, high demand). Learning was assessed with a no-feedback recall test 1 day after practice. Performance was quantified using a root mean square error difference between the goal and participant-generated movement. Results. All participants improved with practice. Under the low-demand practice condition, adults with PD demonstrated comparable learning to that of controls when nominal task difficulty was low but not high. In contrast, under the high-demand practice condition, adults with PD demonstrated preserved motor learning for both levels of task difficulty, but only if recall was tested under the same context as that used during practice. Conclusions. In general, the predictions of CPF were supported. Together, the level of nominal task difficulty and the inherent demand of the practice condition played a critical role in determining the optimal challenge point for motor learning in individuals with PD. More important, and in contrast to the predictions of CPF, a high-demand practice condition appeared to have a facilitative effect on motor learning. However, this benefit revealed the context specificity of motor learning in adults with PD.

The effect of developmental regulation on visual attention: The example of the "biological clock"

The current study investigated the attentional mechanisms associated with goal engagement and disengagement in a lifespan context. Women approaching the end of their childbearing years (N = 29) were compared with women who had passed that deadline (N = 28). Participants' goal engagement was measured with a goal nomination task, an incidental recall task of goal-relevant sentences, visual attention to goal-relevant vs. goal-irrelevant images, and a memory task of goal-relevant images. The attention data indicated that women approaching the deadline had a longer first fixation on baby images than women who had passed the deadline. This novel finding was supported by a replication of the previous finding that women approaching the deadline were more engaged with the goal of childbearing than women who had passed the deadline. The connection between attention and memory of goal-relevant information is explored as evidence of cognition working in the service of motivation and developmental regulation.

Sociocultural development and validation of lexicon for Asian-Indian individuals who use augmentative and alternative communication

Purpose. Individuals who temporarily or permanently are not able to communicate through use of gestures/signs, speech, and/or written communication mode benefit from the use of augmentative and alternative communication (AAC) systems. Effective communication skills for individuals who use an AAC system depend on appropriate lexicon. This study was designed to develop and validate a socially and culturally appropriate lexicon for Asian-Indians who use AAC.Method. To this end, 120 individuals from India participated in this study. A composite list of lexical items was identified, using a structured social validation technique involving non-categorical and categorical nominations, and a rating of lexical items from a Picture Communication Symbols (PCS) lexicon.Results. Data analysis indicated that 88 lexical items from the nomination task were not represented in the PCS lexicon and 247 items were rated as having no value for the Asian-Indian culture.Conclusions. Findings suggest that while a lexicon from symbol sets developed for one culture might have considerable overlap across cultures, these lexicons may not be appropriate as a source of selecting a lexicon for an AAC user from a culturally and linguistically diverse background. Implications of these findings are discussed for speech-language pathologists and other rehabilitation professionals.

Evaluation of the Space Shuttle Cockpit Avionics Upgrade (CAU) Displays

In 1999, NASA Johnson Space Center (JSC) initiated a Cockpit Avionics Upgrade (CAU) project to increase shuttle mission safety by improving the crew's situation awareness, reducing their workload, and improving their performance. The primary focus of the project was a complete redesign of the current cockpit displays. To determine the effectiveness of the redesigns, a human-centered evaluation was conducted in the Shuttle Mission Simulator (SMS) at NASA JSC in 2003 and 2004. Measures of crew situation awareness, workload, and nominal and off-nominal task handling performance were made in a series of simulations of off-nominal flight situations during the dynamic flight phases of ascent and entry. The redesigned display formats yielded dramatic increases in situation awareness, reductions in workload, and improvements in performance.

The facilitating effect of verbalization on the recognition memory of incidentally learned faces

AbstractThe purpose of this study was to test the hypothesis that requiring people to verbally describe a target face from memory facilitates their subsequent recognition when their memory for the target is poor and interferes with recognition when such memory is strong. In Experiment 1, a target face was presented to participants for 30 s or 100 s under a nominal task instruction, and they incidentally familiarized themselves with it. Verbalization increased the rate of correct recognition only when the target was presented for 30 s and the performance of control participants was poor. In Experiment 2, participants observed a target without instruction for intentional learning or other nominal instruction, in a more ecologically valid context. Recognition performance was poor for control participants and verbalization increased the rate of correct recognition. These results appear to support the hypothesis. The implications for the identification of persons by eyewitnesses are discussed. Copyright © 2005 John Wiley & Sons, Ltd.

Social Anxiety and Peer Relations Among Adolescents: Testing a Psychobiological Model

This study tested hypotheses derived from Trower and Gilbert’s (1989) model of social anxiety. Participants were 1,179 students (594 males and 585 females) in grades 6, 7, 8, 9, and 11. Participants completed the Social Anxiety Scale for Adolescents and a sociometric nomination task. Nominations from the following behavioral descriptors: most cooperative, class leader, fights the most, and easiest to push around, were used to classify students into four peer nomination groups (i.e., cooperative, friendly dominant, hostile dominant, and submissive). Results indicated that students classified as submissive reported greater social anxiety than those classified as cooperative, friendly dominant, and hostile dominant. Implications of these results for further study of the Trower and Gilbert (1989) model of social anxiety are discussed.

The role of social anxiety in adolescent peer relations: Differences among sociometric status groups and rejected subgroups

Examined the relation between sociometric nominations and social anxiety in adolescence. Participants were 973 students (473 boys and 500 girls) in Grades 6, 7, 8, and 9. Students completed the Social Anxiety Scale for Adolescents and a sociometric nomination task that included the following behavioral descriptors: liked most, liked least, starts fights the most, best sense of humor, class leader, easiest to push around, and most cooperative. Sociometric nominations were used to classify students into standard sociometric status groups (i.e., popular, average, rejected, neglected, and controversial) well as into rejected subgroups (aggressive rejected and submissive rejected): Reports indicated that students classified as rejected and neglected reported more social anxiety than those classified as average, popular, or controversial. In addition, submissive rejected students reported significantly more social anxiety than did aggressive rejected or average students. Implications of these results for assessment and treatment of adolescents with peer problems are discussed.

Differential recovery in naming in bilingual aphasics

Language performance in a sample of 30 Catalan-Spanish bilingual aphasics was studied using three nominal tasks (naming, pointing, and translation). We compared performance between the two languages before and after therapy and also compared the improvements made in each language. Therapy was carried out in only one language, namely Catalan. Significant differences between the two languages were initially seen in the naming and translation tasks while after treatment significant differences were observed in the naming and pointing tasks. Analysis of covariance was carried out to control the influence of the initial performance on improvements. Performance in the naming task improved more in the treated language (Catalan) than in the nontreated language. We conclude that both differential impairment and recovery of languages in bilingual aphasics is seen not only in rare cases but also in studies of larger samples.

Increment detection, intensity discrimination, and tone decay at high frequencies

Continuous high‐frequency tones decay to inaudibility several seconds after onset. We have studied this phenomenon in “normal‐hearing” subjects by measuring the just‐detectable intensity increment in a continuous 16‐kHz tone and the just‐detectable intensity difference between two 16‐kHz, 200‐ms tone pulses. Over the wide range of intensities examined, the continuous tone became inaudible and the nominal task of increment detection become absolute detection. The continuous tone did, however, elevate the threshold: at 100 dB, for example, the continuous tone raised the “detection” threshold by approximately 50 dB. More generally, the results are similar to those observed at lower frequencies: the Weber fraction (ΔI/I) was slightly lower for increment detection than for intensity discrimination and, in both eases, decreased slightly with increasing intensity. These data suggest that high‐frequency tone decay results from an attenuative, rather than a subtractive, process and, in this respect, difffers fundamentally from the adaptation of primary fibers. [Supported by NINCDS NS12125.]

Visual and Figural Elaboration in Preadolescents

of paired-associate learning and figural elaboration as found in the graphic representations of preadolescents and as measured by nonverbal creativity measures. For the purpose of this study, the following definitions are used throughout: Paired-associate learning is a method used by experimental psychologists to study memory in terms of recalling pairs of items. The paired-associate tasks utilized in this study are specified by the 1:1 pattern: each of the stimulus members is paired with only one of the response members (Goss & Nodine, 1965). Elaboration is the ability to add detail, embellish an idea, or to make a personal contribution to a nominal idea or task.

Children's Difficulty with Word-Referent Differentiation

MARKMAN, ELLEN M. Children's Difficulty with Word-Referent Differentiation. CHILD DEVELOPMENT, 1976, 47, 742-749. An analysis of the cognitive demands of nominal realism tasks yielded 3 related hypotheses concerning children's poor performance: (a) children fail to clearly differentiate linguistic from empirical properties, with (b) the empirical properties being more salient due in part to (c) the intangibility of words. It was found in Study I that kindergarten and first-grade children perform better on analogous tasks involving pictorial representation where the symbol is as tangible as its referent, thus supporting (c). In Study II, hypothesis a was tested by differentiating linguistic and nonlinguistic properties for the firstand second-grade subjects and hypothesis b was tested by determining whether children were as likely to attribute properties of words to their referents. The data from the first graders were fully consistent, but the data from the second graders were only partially consistent with the hypotheses. The unexpected findings could be explained by postulating 2 advances in metalinguistic development in second graders. Though speculative, this explanation was shown to be in accord with previous research and with supplementary data analyses.