Nominal Task Research Articles

Determining the optimal challenge point for learning motor skills in children with attention deficit/hyperactivity disorder

The purpose of this study was to investigate the optimal challenge point for learning motor skills in children with and without attention deficit/hyperactivity disorder (ADHD). Ninety-six 9- to 10-year-old children, including 48 children with ADHD and 48 neurotypical children, were randomly assigned to one of four practice groups with varying levels of nominal and functional task difficulty. They performed 63 trials of a dart throwing task in the acquisition phase and 18 trials in the retention and transfer tests a day later. The results showed that neurotypical children outperformed children with ADHD in all phases of the study. Both groups improved in the acquisition phase and performed better in the retention and transfer tests. Interestingly, low nominal task difficulty was associated with better learning for both groups, despite lower average performance for children with ADHD. Thus, despite their performance differences, we did not find a difference in the effective challenge point between children with ADHD and their neurotypical peers.

A rapid time-coordinated longitudinal guidance method for high-speed vehicle

Compared to the traditional method of adjusting flight time by increasing lateral maneuverability [1-2], a faster time-coordinated longitudinal guidance method for unpowered high-speed vehicles has been proposed in this paper. Firstly, the centroid dynamics model and flight constraint model of unpowered high-speed vehicles were established, and the angle of attack corridor was derived based on quasi-equilibrium gliding conditions (QEGC). Then, to plan a reasonable angle of attack profile, the flight capability of a single vehicle under different constant angles of attack is analyzed, including terminal altitude, terminal velocity, and terminal arrival time. Furthermore, to achieve a long-term high angle of attack flight, a rapid time-coordinated longitudinal guidance method based on a trapezoidal angle of attack profile was proposed. Finally, using the vehicle and its performance parameters from Chapter 3 [3], numerical simulations were conducted under nominal tasks and multi-vehicle collaborative tasks. The simulation results show that under different expected arrival times, this method can quickly plan the angle of attack profile that satisfies time constraints, with high computational efficiency. Moreover, the arrival time adjustment ability of this method is large, which can fully utilize the arrival time capability of the high-speed vehicle. The above research provides more convenient conditions for a collaborative flight of multiple vehicles.

Increasing recognition of historically marginalized scientists: Lessons learned from the Nomination Task Force

The Space Physics and Aeronomy (SPA) Section of the American Geophysical Union (AGU) created a Nomination Task Force (NTF) in 2017 upon concerns that the numbers of women nominated for AGU Fellow were significantly lower than would be expected based on SPA membership representation, including as low as zero in two of the four preceding years. Now that the NTF has been in existence through four cycles of AGU Honors and Awards, the outcomes indicate the success of the NTF in increasing the number of nominations for scientists from historically marginalized groups. These data indicate that the work of the NTF has enhanced the nomination pool rather than occurring at the expense of other nominees. Until recently, the ability to collect and distribute demographic information has been limited, and cisgender binary identities are often inferred. Moving forward it is a goal of AGU to be more inclusive and intentional with respect to gender, racial, and ethnic identities. We share our best practices and success stories with a broad audience to help others build upon the work of the NTF within their own institutions and professional groups. We also discuss challenges that we are still facing and provide suggestions for continuing to improve the process.

Future needs of human reliability analysis: The interaction between new technology, crew roles and performance

Human Reliability Analysis (HRA) is an important part of probabilistic risk/safety assessment (PRA/PSA) for nuclear power plants (NPPs). Data has played a central part in HRA, to underpin nominal task probabilities, providing time reliability estimates, and as a basis for multipliers for performance shaping factors (PSFs). New NPPs apply digital instrumentation & control (I&C) systems to support monitoring and control. Will this require new or updated HRA methods and more data as compared to today? We have seen that the combination of the new I&C technology and how it is used by the crew is decisive for the performance of the joint system, comprising the crew and the I&C technology. This paper focuses on the way in which new technology may affect human performance as well as the relation between crew roles, teamwork, and performance. For HRA, two questions are important: What is the impact of teamwork and assigned crew roles on recovery from failure and upset plant conditions? And how should dependency be treated in modern control rooms? This paper discusses these matters based on empirical studies in the OECD Halden Reactor Project and underlines the importance of empirical studies on these topics, since the interactions between new technology, prescribed work processes and actual practices, and crew behavior, are often not obvious. This paper is an extension of a paper presented at the ESREL 2020 – PSAM15 conference.

Distance-based positive and unlabeled learning for ranking

Learning to rank – producing a ranked list of items specific to a query and with respect to a set of supervisory items – is a problem of general interest. The setting we consider is one in which no analytic description of what constitutes a good ranking is available. Instead, we have a collection of representations and supervisory information consisting of a (target item, interesting items set) pair. We demonstrate analytically, in simulation, and in real data examples that learning to rank via combining representations using an integer linear program is effective when the supervision is as light as “these few items are similar to your item of interest.” While this nomination task is quite general, for specificity we present our methodology from the perspective of vertex nomination in graphs. The methodology described herein is model agnostic.

A Task-Based Post-Impact Safety Protocol Based on Energy Tanks

As situations with robots working in human environments are becoming increasingly important, the aspect of safety is crucial. As a consequence, the design of human friendly robots has been intensively researched in the past years, producing both mechanical and control design advancements. In this work, a safety-aware control architecture is proposed in a scenario in which a predefined task has to be executed. At the core of its implementation, a novel dynamic energy injection protocol is introduced for energy tanks. Contrarily to their most common employment in the past, energy tanks are used to provide relevant information on energy flows used by the safety protocol, rather than to guarantee passivity of the controlled robot, which does not imply safety. The algorithm is able to detect collisions and divergence from nominal task execution by identifying unwanted energy flows, encoded in the energy tanks. A reaction strategy based on low impedance control is implemented in case of collision detection. Experiments on a 7-DoF manipulator successfully validate the proposed strategy.

Decentralized Ability-Aware Adaptive Control for Multi-Robot Collaborative Manipulation

Multi-robot teams can achieve more dexterous, complex and heavier payload tasks than a single robot, yet effective collaboration is required. Multi-robot collaboration is extremely challenging due to the different kinematic and dynamics capabilities of the robots, the limited communication between them, and the uncertainty of the system parameters. In this letter, a Decentralized Ability-Aware Adaptive Control (DA <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> C) is proposed to address these challenges based on two key features. Firstly, the common manipulation task is represented by the proposed nominal task ellipsoid, which is used to maximize each robot's force capability online via optimizing its configuration. Secondly, a decentralized adaptive controller is designed to be Lyapunov stable in spite of heterogeneous actuation constraints of the robots and uncertain physical parameters of the object and environment. In the proposed framework, decentralized coordination and load distribution between the robots is achieved without communication, while only the control deficiency is broadcast if any of the robots reaches its force limits. In this case, the object's reference trajectory is modified in a decentralized manner to guarantee stable interaction. Finally, we perform several numerical and physical simulations to analyse and verify the proposed method with heterogeneous multi-robot teams in collaborative manipulation tasks.

Understanding learner behaviour in online courses with Bayesian modelling and time series characterisation

The intrinsic temporality of learning demands the adoption of methodologies capable of exploiting time-series information. In this study we leverage the sequence data framework and show how data-driven analysis of temporal sequences of task completion in online courses can be used to characterise personal and group learners’ behaviors, and to identify critical tasks and course sessions in a given course design. We also introduce a recently developed probabilistic Bayesian model to learn sequential behaviours of students and predict student performance. The application of our data-driven sequence-based analyses to data from learners undertaking an on-line Business Management course reveals distinct behaviors within the cohort of learners, identifying learners or groups of learners that deviate from the nominal order expected in the course. Using course grades a posteriori, we explore differences in behavior between high and low performing learners. We find that high performing learners follow the progression between weekly sessions more regularly than low performing learners, yet within each weekly session high performing learners are less tied to the nominal task order. We then model the sequences of high and low performance students using the probablistic Bayesian model and show that we can learn engagement behaviors associated with performance. We also show that the data sequence framework can be used for task-centric analysis; we identify critical junctures and differences among types of tasks within the course design. We find that non-rote learning tasks, such as interactive tasks or discussion posts, are correlated with higher performance. We discuss the application of such analytical techniques as an aid to course design, intervention, and student supervision.

Human Multi-Robot Safe Interaction: A Trajectory Scaling Approach Based on Safety Assessment

Nowadays, industrial robotics requires that robots and humans share the same workspace and collaborate to a certain extent. In such a scenario, the safety is the minimum requirement and, for this reason, many off-the-shelf collaborative robots are now available on the market which, basically, are able to limit the contact forces in the case of impact. Differently from many different works, this article presents a solution to human multi-robot safe interaction in which multiple mobile manipulators are in charge of performing a cooperative task in a workspace shared with human operators. The safety of the interaction is assessed by a safety field that considers the whole system and is general enough concerning its expression. Based on the value of this field, the cooperative task trajectory is properly modified so as to ensure a safe interaction while trying to preserve as much as possible the nominal task, which is instead completely aborted whenever the safety of the interaction cannot be guaranteed. The solution is first designed within a centralized architecture and, then, upon this, a distributed implementation is presented, which, in general, aims to exhibit the same performance as the centralized counterpart. Finally, both simulations and experiments on real industrial robots corroborate the designed solution.

The effects of motor modularity on performance, learning and generalizability in upper-extremity reaching: a computational analysis.

It has been hypothesized that the central nervous system simplifies the production of movement by limiting motor commands to a small set of modules known as muscle synergies. Recently, investigators have questioned whether a low-dimensional controller can produce the rich and flexible behaviours seen in everyday movements. To study this issue, we implemented muscle synergies in a biomechanically realistic model of the human upper extremity and performed computational experiments to determine whether synergies introduced task performance deficits, facilitated the learning of movements, and generalized to different movements. We derived sets of synergies from the muscle excitations our dynamic optimizations computed for a nominal task (reaching in a plane). Then we compared the performance and learning rates of a controller that activated all muscles independently to controllers that activated the synergies derived from the nominal reaching task. We found that a controller based on synergies had errors within 1 cm of a full-dimensional controller and achieved faster learning rates (as estimated from computational time to converge). The synergy-based controllers could also accomplish new tasks-such as reaching to targets on a higher or lower plane, and starting from alternative initial poses-with average errors similar to a full-dimensional controller.

Vertex nomination: The canonical sampling and the extended spectral nomination schemes

Suppose that one particular block in a stochastic block model is of interest, but block labels are only observed for a few of the vertices in the network. Utilizing a graph realized from the model and the observed block labels, the vertex nomination task is to order the vertices with unobserved block labels into a ranked nomination list with the goal of having an abundance of interesting vertices near the top of the list. There are vertex nomination schemes in the literature, including the optimally precise canonical nomination scheme LC and the consistent spectral partitioning nomination scheme LP. While the canonical nomination scheme LC is provably optimally precise, it is computationally intractable, being impractical to implement even on modestly sized graphs.With this in mind, an approximation of the canonical scheme – denoted the canonical sampling nomination schemeLCS – is introduced; LCS relies on a scalable, Markov chain Monte Carlo-based approximation of LC, and converges to LC as the amount of sampling goes to infinity. The spectral partitioning nomination scheme is also extended to the extended spectral partitioning nomination scheme, LEP, which introduces a novel semisupervised clustering framework to improve upon the precision of LP. Real-data and simulation experiments are employed to illustrate the precision of these vertex nomination schemes, as well as their empirical computational complexity.

Development of Embedded Boot Software for a Satellite Instrument Control Unit: Lessons Learned

A satellite spacecraft is generally composed of a central Control and Data Management Unit (CDMU) and several instruments, each one locally controlled by its Instrument Control Unit (ICU). Inside each ICU, the embedded boot software (BSW) is the very first piece of software executed after power-up or reset. The ICU BSW is a nonpatchable, stand-alone, real-time software package that initializes the ICU HW, performs self-tests, and waits for CDMU commands to maintain on-board memory and ultimately start a patchable application software (ASW), which is responsible for execution of the nominal tasks assigned to the ICU (control of the satellite instrument being the most important one). The BSW is a relatively small but critical software item, since an unexpected behaviour can cause or contribute to a system failure resulting in fatal consequences such as the satellite mission loss. The development of this kind of embedded software is special in many senses, primarily due to its criticality, real-time expected performance, and the constrained size of program and data memories. This paper presents the lessons learned in the development and HW/SW integration phases of a satellite ICU BSW designed for a European Space Agency mission.

On the Role of Attention in Working Memory for Response Selection in Task Switching.

Oberauer’s (2019) analysis and related research on how working memory and attention are linked can provide insight regarding how responses are selected in task-switching situations. One mechanism for response selection—the mediated route—categorizes stimuli with respect to both tasks, then activates responses based on instructed category–response associations. The author discusses two proposals for how these associations are represented in working memory, both of which seem consistent with the idea that attention selects or prioritizes the relevant-task associations, enabling accurate response selection. A broader implication of the representation and operation of the mediated route is that nominal task switching might reflect concurrent multitasking within the cognitive system (constrained by attention in working memory), raising the issue of how task switching should be characterized.

Identifying Classroom Friendships: Teachers’ Confidence and Agreement With Children

We conducted an exploratory study to investigate teachers’ confidence and agreement with children when teachers and children identified close classroom friendships. Participants comprised six kindergarten teachers and 110 children, including 26 children with disabilities. Data were gathered from a friendship nomination questionnaire completed by teachers and a friendship nomination task completed by children. On average, teachers accurately identified one peer that a target child also named as a “best friend.” Teachers also identified children selected as “very best friends” for 59% of their students when using a less conservative definition of very best friendship. Teachers reported being confident in identifying friendships, on average, for 39% of their class. However, greater confidence did not equate with more accurate reports. Although teachers were slightly more confident in their friendship reports for children with disabilities, they were also less accurate. Implications for supporting friendship development and future research are discussed.

Poly-Victimization in Polish Adolescents: Risk Factors and the Moderating Role of Coping.

This study aimed to investigate the prevalence of poly-victimization in Polish adolescents and assess factors associated with poly-victimization risk across different ecological levels. This study further examined whether coping styles could moderate the impact of poly-victimization on emotional well-being. Participants were 454 adolescents, aged between 13 and 19 years, from an urban region of Poland. Adolescents completed self-report measures assessing community, school, and family risks, along with a peer nomination task measuring social preference. Teachers also completed a measure assessing adolescent problem behaviors. Findings revealed that the majority of the sample (70%) experienced more than one type of victimization in the past year, and 35.7% were classified as poly-victims (≥ 6 victimizations). As hypothesized, community disorganization, low commitment to school, poor family management, family conflict, peer social preference, and teacher-rated withdrawn and disruptive behavioral problems were predictive of poly-victimization. In addition, the relationship between poly-victimization and emotional well-being was moderated by problem-solving coping, in that greater use of problem-solving strategies lessened the negative impact of poly-victimization on positive affect and life satisfaction. Other investigated coping strategies (social support-seeking, internalizing, externalizing, and distraction) failed to demonstrate any moderation effect. Findings highlight the high rate of victimization experienced by adolescents in Poland and have implications for the identification of those at risk of poly-victimization, suggesting that there is a need to consider factors related to the adolescent themselves, their relationships with family and peers, and school and community factors. Results also indicate that there may be value in training victims in the use of problem-solving coping styles as a source of resilience.

On the consistency of the likelihood maximization vertex nomination scheme

Given a graph in which a few vertices are deemed interesting a priori, the vertex nomination task is to order the remaining vertices into a nomination list such that there is a concentration of int...

Suggested improvements to the definitions of Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H) performance shaping factors, their levels and multipliers and the nominal tasks

This paper discusses the definitions and content of eight performance shaping factors (PSFs) used in Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H) and their levels and multipliers. Definitions of nominal tasks are also discussed. The discussion is based on a review of literature on PSFs, interviews with consultants who have carried out SPAR-H analysis in the petroleum industry and an evaluation of human reliability analysis reports based on SPAR-H analysis. We concluded that SPAR-H definitions and descriptions of the PSFs are unclear and overlap too much, making it difficult for the analyst to choose between them and select the appropriate level. This reduces inter-rater reliability and thus the consistency of SPAR-H analyses. New definitions of the PSFs, levels and multipliers are suggested with the aim to develop more specific definitions of the PSFs in order to increase the inter-rater reliability of SPAR-H. Another aim was to construct more varied and more nuanced levels and multipliers to improve the capacity of SPAR-H analysis to capture the degree of difficulty faced by operators in different scenarios. We also suggest that only one of two nominal SPAR-H tasks should be retained owing to the difficulty in distinguishing between them.

Nominal and functional task difficulty in skill acquisition: Effects on performance in two tests of transfer

The influence of nominal and functional task difficulty during the acquisition of a motor skill was examined in two tests of transfer of learning. The task involved a ballistic, target-directed, finger action. Nominal task difficulty was defined as the distance of the target from the home position. Functional task difficulty was created by manipulating the progression of target distances during practice. Based on the challenge point framework (Guadagnoli & Lee, 2004), we predicted that practice with a set of targets farther away from the performer would benefit from less functional task difficulty, while practice with a closer set of targets would benefit from more functional task difficulty. In single-task transfer tests, learners who practiced using the high nominal task difficulty targets benefitted in terms of persistence of performance over time. In dual-task transfer tests, groups with an intermediate combined (nominal and functional) task difficulty performed with greater persistence over time on tests of transfer than those who practiced with the highest or lowest combined difficulty. Together these findings suggest that the influences of nominal and functional task difficulty during acquisition are weighted differentially depending upon the transfer test context. The challenge point framework does not accurately capture this complex relationship in its current form.

The impact of different aetiologies on the cognitive performance of frontal patients

Neuropsychological group study methodology is considered one of the primary methods to further understanding of the organisation of frontal ‘executive’ functions. Typically, patients with frontal lesions caused by stroke or tumours have been grouped together to obtain sufficient power. However, it has been debated whether it is methodologically appropriate to group together patients with neurological lesions of different aetiologies. Despite this debate, very few studies have directly compared the performance of patients with different neurological aetiologies on neuropsychological measures. The few that did included patients with both anterior and posterior lesions.We present the first comprehensive retrospective comparison of the impact of lesions of different aetiologies on neuropsychological performance in a large number of patients whose lesion solely affects the frontal cortex. We investigated patients who had a cerebrovascular accident (CVA), high (HGT) or low grade (LGT) tumour, or meningioma, all at the post-operative stage. The same frontal ‘executive’ (Raven's Advanced Progressive Matrices, Stroop Colour-Word Test, Letter Fluency-S; Trail Making Test Part B) and nominal (Graded Naming Test) tasks were compared. Patients' performance was compared across aetiologies controlling for age and NART IQ scores. Assessments of focal frontal lesion location, lesion volume, global brain atrophy and non-specific white matter (WM) changes were undertaken and compared across the four aetiology.We found no significant difference in performance between the four aetiology subgroups on the ‘frontal’ executive and nominal tasks. However, we found strong effects of premorbid IQ on all cognitive tasks and robust effects of age only on the frontal tasks. We also compared specific aetiology subgroups directly, as previously reported in the literature. Overall we found no significant differences in the performance of CVA and tumour patients, or LGT and HGT patients or LGT, HGT and meningioma's on our four frontal tests. No difference was found with respect to the location of frontal lesions, lesion volume, global brain atrophy and non-specific WM changes between the subgroups.Our results suggest that the grouping of frontal patients caused by different aetiologies is a pragmatic, justified methodological approach that can help to further understanding of the organisation of frontal executive functions.

異なる詳細さで報告するスキルの発達──だいたいと正確──

This study examined the development of skills to report with different levels of exactness. A total of 62 first-grade children and 58 fourth-grade children were asked about numbers and lengths (numeral tasks) and colors and positions of objects (nominal tasks) with instructions suggesting different levels of exactness, "roughly" or "exactly". In Study 1, the instructions were given as a between-subjects factor. The results showed that when the "roughly" instruction was given, participants gave approximate answers more frequently than when the "exactly" instruction was given especially in the numeral tasks, and older children did so more frequently than younger children. In Study 2, the instructions were given as a within-subjects factor: a half of participants were given "roughly" and then "exactly" instructions, and the others were given the instructions in the opposite order. The results showed that younger children could change the levels of answers depending on instruction in the numeral tasks but not in the nominal tasks, whereas older children could do so in both tasks. The results suggest that the skills for reporting with different levels of exactness are related not only to cognitive development, but also to the linguistic context, such as the tasks and instructions.