Grouping-based adaptive spatial formation of swarm robots in a dynamic environment

Spatial formations of swarm robots are increasingly applied in many domains in which the environments are dynamic and unpredictable. The autonomy of the individual robots and decentralization of the entire system increase the complexity of the response to environmental changes, which could prolong the formation convergence and significantly increase the communication cost. To address these issues, we propose an adaptive mechanism with three basic behaviours for each individual robot and design a grouping-based spatial formation algorithm for swarm robots to respond to changes and accomplish shape formation. Specifically, the robots are automatically partitioned into several groups based on their spatial neighbours. In this manner, the interactions and self-organization of robots are primarily performed at the intra-group rather than inter-group level, leading to decreased communication costs. Furthermore, this grouping mechanism naturally supports parallel formation and therefore improves the convergence speed. Our simulation and experimental results demonstrate that the proposed method significantly improves the convergence speed and decreases the communication cost, thus validating the effectiveness of the proposed adaptive mechanism.

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Collective Motion and Self-Organization of a Swarm of UAVs: A Cluster-Based Architecture

Sensors ◽

10.3390/s21113820 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3820

Author(s):

Zain Anwar Ali ◽

Zhangang Han ◽

Rana Javed Masood

Keyword(s):

Graph Theory ◽

Collective Motion ◽

Optimal Path ◽

Dynamic Environment ◽

Self Organization ◽

Nsga Ii ◽

Multi Agent ◽

The Individual ◽

Multiple Clusters ◽

Leader Selection

This study proposes a collective motion and self-organization control of a swarm of 10 UAVs, which are divided into two clusters of five agents each. A cluster is a group of UAVs in a dedicated area and multiple clusters make a swarm. This paper designs the 3D model of the whole environment by applying graph theory. To address the aforesaid issues, this paper designs a hybrid meta-heuristic algorithm by merging the particle swarm optimization (PSO) with the multi-agent system (MAS). First, PSO only provides the best agents of a cluster. Afterward, MAS helps to assign the best agent as the leader of the nth cluster. Moreover, the leader can find the optimal path for each cluster. Initially, each cluster contains agents at random positions. Later, the clusters form a formation by implementing PSO with the MAS model. This helps in coordinating the agents inside the nth cluster. However, when two clusters combine and make a swarm in a dynamic environment, MAS alone is not able to fill the communication gap of n clusters. This study does it by applying the Vicsek-based MAS connectivity and synchronization model along with dynamic leader selection ability. Moreover, this research uses a B-spline curve based on simple waypoint defined graph theory to create the flying formations of each cluster and the swarm. Lastly, this article compares the designed algorithm with the NSGA-II model to show that the proposed model has better convergence and durability, both in the individual clusters and inside the greater swarm.

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QUALITY OF INDIVIDUAL AND GROUP LEVEL INTERVENTIONS FOR FIRST EPISODE PSYCHOSIS AT THE TERTIARY PSYCHIATRIC HOSPITAL IN UGANDA.

10.31234/osf.io/hrygs ◽

2020 ◽

Author(s):

Emmanuel Kiiza Mwesiga ◽

Noeline Nakasujja ◽

Lawrence Nankaba ◽

Juliet Nakku ◽

Seggane Musisi

Keyword(s):

Psychiatric Hospital ◽

Psychotic Disorders ◽

First Episode Psychosis ◽

First Episode ◽

Group Level ◽

Group Interventions ◽

Episode Psychosis ◽

Essential Components ◽

The Individual

Introduction: Individual and group level interventions have the largest effect on outcomes in patients with the first episode of psychosis. The quality of these individual and group level interventions provided to first-episode psychosis patients in Uganda is unclear.Methods: The study was performed at Butabika National Psychiatric Teaching and referral hospital in Uganda. A retrospective chart review of recently discharged adult in-patients with the first episode of psychosis was first performed to determine the proportion of participants who received the different essential components for individual and group level interventions. From the different proportions, the quality of the services across the individual and group interventions was determined using the first-Episode Psychosis Services Fidelity Scale (FEPS-FS). The FEPS-FS assigns a grade of 1-5 on a Likert scale depending on the proportion of patients received the different components of the intervention. Results: The final sample included 156 first-episode psychosis patients. The median age was 27 years [IOR (24-36)] with 55% of participants of the female gender. 13 essential components across the individual and group interventions were assessed and their quality quantified. All 13 essential components had poor quality with the range of scores on the FEPS-FS of 1-3. Only one essential component assessed (use of single antipsychotics) had moderate quality.Discussion: Among current services at the National psychiatric hospital of Uganda, the essential for individual and group level interventions for psychotic disorders are of low quality. Further studies are required on how the quality of these interventions can be improved.

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Reply to Connor and Evers (2020): Critique of the Bias of Crowds Model Simply Restates the Model

10.31234/osf.io/ph7yt ◽

2020 ◽

Author(s):

Keith Payne ◽

Heidi A. Vuletich ◽

Kristjen B. Lundberg

Keyword(s):

Implicit Bias ◽

Group Level ◽

Systemic Racism ◽

Individual Level ◽

The Core ◽

Psychological Science ◽

Implicit Biases ◽

The Individual

The Bias of Crowds model (Payne, Vuletich, & Lundberg, 2017) argues that implicit bias varies across individuals and across contexts. It is unreliable and weakly associated with behavior at the individual level. But when aggregated to measure context-level effects, the scores become stable and predictive of group-level outcomes. We concluded that the statistical benefits of aggregation are so powerful that researchers should reconceptualize implicit bias as a feature of contexts, and ask new questions about how implicit biases relate to systemic racism. Connor and Evers (2020) critiqued the model, but their critique simply restates the core claims of the model. They agreed that implicit bias varies across individuals and across contexts; that it is unreliable and weakly associated with behavior at the individual level; and that aggregating scores to measure context-level effects makes them more stable and predictive of group-level outcomes. Connor and Evers concluded that implicit bias should be considered to really be noisily measured individual construct because the effects of aggregation are merely statistical. We respond to their specific arguments and then discuss what it means to really be a feature of persons versus situations, and multilevel measurement and theory in psychological science more broadly.

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The Epistemology of Groups

10.1093/oso/9780199656608.001.0001 ◽

2020 ◽

Author(s):

Jennifer Lackey

Keyword(s):

Group Level ◽

Social Significance ◽

Individual Group ◽

Key Concepts ◽

Normative Requirements ◽

Group Members ◽

The Individual ◽

Belief Justification ◽

In Virtue Of ◽

Trump Administration

Groups are often said to bear responsibility for their actions, many of which have enormous moral, legal, and social significance. The Trump Administration, for instance, is said to be responsible for the U.S.’s inept and deceptive handling of COVID-19 and the harms that American citizens have suffered as a result. But are groups subject to normative assessment simply in virtue of their individual members being so, or are they somehow agents in their own right? Answering this question depends on understanding key concepts in the epistemology of groups, as we cannot hold the Trump Administration responsible without first determining what it believed, knew, and said. Deflationary theorists hold that group phenomena can be understood entirely in terms of individual members and their states. Inflationary theorists maintain that group phenomena are importantly over and above, or otherwise distinct from, individual members and their states. It is argued that neither approach is satisfactory. Groups are more than their members, but not because they have “minds of their own,” as the inflationists hold. Instead, this book shows how group phenomena—like belief, justification, and knowledge—depend on what the individual group members do or are capable of doing while being subject to group-level normative requirements. This framework, it is argued, allows for the correct distribution of responsibility across groups and their individual members.

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Examining the Effects of Three Group-Level Metacognitive Scaffoldings on In-Service Teachers’ Knowledge Building

Journal of Educational Computing Research ◽

10.1177/07356331211030847 ◽

2021 ◽

pp. 073563312110308

Author(s):

Fan Ouyang ◽

Si Chen ◽

Yuqin Yang ◽

Yunqing Chen

Keyword(s):

Small Groups ◽

Mixed Method ◽

Peer Interactions ◽

Knowledge Building ◽

Group Level ◽

Question Asking ◽

Individual Level ◽

The Individual ◽

Task Oriented ◽

Metacognitive Scaffolding

Group-level metacognitive scaffolding is critical for productive knowledge building. However, previous research mainly focuses on the individual-level metacognitive scaffoldings in helping learners improve knowledge building, and little effort has been made to develop group-level metacognitive scaffolding (GMS) for knowledge building. This research designed three group-level metacognitive scaffoldings of general, task-oriented, and idea-oriented scaffoldings to facilitate in-service teachers’ knowledge building in small groups. A mixed method is used to examine the effects of the GMSs on groups’ knowledge building processes, performances, and perceptions. Results indicate a complication of the effects of GMSs on knowledge building. The idea-oriented scaffolding has potential to facilitate question-asking and perspective-proposing inquiry through peer interactions; the general scaffolding does not necessarily lessen teachers’ idea-centered explanation and elaboration on the individual level; the task-oriented scaffolding has the worst effect. Pedagogical and research implications are discussed to foster knowledge building with the support of GMSs.

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When physical activity meets the physical environment: precision health insights from the intersection

Environmental Health and Preventive Medicine ◽

10.1186/s12199-021-00990-w ◽

2021 ◽

Vol 26 (1) ◽

Author(s):

Luisa V. Giles ◽

Michael S. Koehle ◽

Brian E. Saelens ◽

Hind Sbihi ◽

Chris Carlsten

Keyword(s):

Physical Activity ◽

Physical Environment ◽

Environmental Changes ◽

Main Body ◽

Or Groups ◽

Optimizing Design ◽

Physical Activity Recommendations ◽

The Individual ◽

Precision Health ◽

Activity Recommendations

Abstract Background The physical environment can facilitate or hinder physical activity. A challenge in promoting physical activity is ensuring that the physical environment is supportive and that these supports are appropriately tailored to the individual or group in question. Ideally, aspects of the environment that impact physical activity would be enhanced, but environmental changes take time, and identifying ways to provide more precision to physical activity recommendations might be helpful for specific individuals or groups. Therefore, moving beyond a “one size fits all” to a precision-based approach is critical. Main body To this end, we considered 4 critical aspects of the physical environment that influence physical activity (walkability, green space, traffic-related air pollution, and heat) and how these aspects could enhance our ability to precisely guide physical activity. Strategies to increase physical activity could include optimizing design of the built environment or mitigating of some of the environmental impediments to activity through personalized or population-wide interventions. Conclusions Although at present non-personalized approaches may be more widespread than those tailored to one person’s physical environment, targeting intrinsic personal elements (e.g., medical conditions, sex, age, socioeconomic status) has interesting potential to enhance the likelihood and ability of individuals to participate in physical activity.

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Comparative physical activity as a global question to assess physical activity among university students

BMC Sports Science Medicine and Rehabilitation ◽

10.1186/s13102-021-00247-7 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Katharina Diehl ◽

Alessia Brassat ◽

Jennifer Hilger-Kolb

Keyword(s):

Physical Activity ◽

University Students ◽

Online Survey ◽

Group Level ◽

Comparative Measurement ◽

Cross Sectional ◽

Physically Active ◽

Comparative Optimism ◽

Individual Assessment ◽

The Individual

Abstract Background To assess physical activity (PA), a comparative measurement – evaluating one’s own PA compared to others – may be an appropriate method. In previous studies, the use of comparative measurements led to an effect known as unrealistic comparative optimism (UCO) – people being unrealistically optimistic about their behavior. Our aim was to use this comparative measurement in university students to quantify the prevalence of UCO at the group level and to draw conclusions on its validity. Methods We used data from the Nutrition and Physical Activity in Adolescence Study (NuPhA), a cross-sectional online survey that included only self-reports (n = 689). To assess PA among students, they were asked to rate their PA level compared to that of their same-aged fellow students. In addition, we used the Godin-Shephard leisure-time PA questionnaire and other questions on PA for comparisons. We used bivariate and cluster-based analyses to identify potential UCO. Results We found that UCO at the group level led to an uneven distribution, with a higher proportion of students who rated themselves as being more physically active than average. However, the individual assessment of PA with a single and simple comparative question seemed to be valid. Discussion A global single comparative question seems useful for studies where PA is measured as a covariate in university students.

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The Protective Role of Butyrate against Obesity and Obesity-Related Diseases

Molecules ◽

10.3390/molecules26030682 ◽

2021 ◽

Vol 26 (3) ◽

pp. 682

Author(s):

Serena Coppola ◽

Carmen Avagliano ◽

Antonio Calignano ◽

Roberto Berni Canani

Keyword(s):

Metabolic Diseases ◽

Environmental Changes ◽

Short Chain Fatty Acids ◽

Protective Role ◽

Health Concern ◽

Predisposing Factor ◽

Alcoholic Fatty Liver ◽

Beneficial Effects ◽

The Individual

Worldwide obesity is a public health concern that has reached pandemic levels. Obesity is the major predisposing factor to comorbidities, including type 2 diabetes, cardiovascular diseases, dyslipidemia, and non-alcoholic fatty liver disease. The common forms of obesity are multifactorial and derive from a complex interplay of environmental changes and the individual genetic predisposition. Increasing evidence suggest a pivotal role played by alterations of gut microbiota (GM) that could represent the causative link between environmental factors and onset of obesity. The beneficial effects of GM are mainly mediated by the secretion of various metabolites. Short-chain fatty acids (SCFAs) acetate, propionate and butyrate are small organic metabolites produced by fermentation of dietary fibers and resistant starch with vast beneficial effects in energy metabolism, intestinal homeostasis and immune responses regulation. An aberrant production of SCFAs has emerged in obesity and metabolic diseases. Among SCFAs, butyrate emerged because it might have a potential in alleviating obesity and related comorbidities. Here we reviewed the preclinical and clinical data that contribute to explain the role of butyrate in this context, highlighting its crucial contribute in the diet-GM-host health axis.

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Prepare: P owe r -Awar e A p proximate Re a l-time Task Scheduling for Ene r gy-Adaptiv e QoS Maximization

ACM Transactions on Embedded Computing Systems ◽

10.1145/3476993 ◽

2021 ◽

Vol 20 (5s) ◽

pp. 1-25

Author(s):

Shounak Chakraborty ◽

Sangeet Saha ◽

Magnus Själander ◽

Klaus Mcdonald-Maier

Keyword(s):

Real Time ◽

Task Scheduling ◽

Processing Speed ◽

Empirical Evaluation ◽

Adaptive Mechanism ◽

Approximate Computing ◽

Thermal Safety ◽

Time Task ◽

Individual Task ◽

The Individual

Achieving high result-accuracy in approximate computing (AC) based real-time applications without violating power constraints of the underlying hardware is a challenging problem. Execution of such AC real-time tasks can be divided into the execution of the mandatory part to obtain a result of acceptable quality, followed by a partial/complete execution of the optional part to improve accuracy of the initially obtained result within the given time-limit. However, enhancing result-accuracy at the cost of increased execution length might lead to deadline violations with higher energy usage. We propose Prepare , a novel hybrid offline-online approximate real-time task-scheduling approach, that first schedules AC-based tasks and determines operational processing speeds for each individual task constrained by system-wide power limit, deadline, and task-dependency. At runtime, by employing fine-grained DVFS, the energy-adaptive processing speed governing mechanism of Prepare reduces processing speed during each last level cache miss induced stall and scales up the processing speed once the stall finishes to a higher value than the predetermined one. To ensure on-chip thermal safety, this higher processing speed is maintained only for a short time-span after each stall, however, this reduces execution times of the individual task and generates slacks. Prepare exploits the slacks either to enhance result-accuracy of the tasks, or to improve thermal and energy efficiency of the underlying hardware, or both. With a 70 - 80% workload, Prepare offers 75% result-accuracy with its constrained scheduling, which is enhanced by 5.3% for our benchmark based evaluation of the online energy-adaptive mechanism on a 4-core based homogeneous chip multi-processor, while meeting the deadline constraint. Overall, while maintaining runtime thermal safety, Prepare reduces peak temperature by up to 8.6 °C for our baseline system. Our empirical evaluation shows that constrained scheduling of Prepare outperforms a state-of-the-art scheduling policy, whereas our runtime energy-adaptive mechanism surpasses two current DVFS based thermal management techniques.

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Isolated individuals and groups show opposite preferences toward humidity

10.1101/398651 ◽

2018 ◽

Author(s):

Mariano Calvo Martín ◽

Stamatios C. Nicolis ◽

Isaac Planas-Sitjà ◽

Jean-Christophe de Biseau ◽

Jean-Louis Deneubourg

Keyword(s):

Relative Humidity ◽

Environmental Conditions ◽

Group Level ◽

Individual Level ◽

Negative Effect ◽

Multi Level ◽

The Individual ◽

Shed Light ◽

Selection Of

AbstractCockroaches, like most social arthropods, are led to choose collectively among different alternative resting places. These decisions are modulated by different factors, such as environmental conditions (temperature, relative humidity) and sociality (groups size, nature of communications). The aim of this study is to establish the interplay between environmental conditions and the modulation of the interactions between individuals within a group leading to an inversion of preferences. We show that the preferences of isolated cockroaches and groups of 16 individuals, on the selection of the relative humidity of a shelter are inversed and shed light on the mechanisms involved. We suggest that the relative humidity has a multi-level influence on cockroaches, manifested as an attractant effect at the individual level and as a negative effect at the group level, modulating the interactions.

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