Flexible Task Allocation Research Articles

Targeted worker removal reveals a lack of flexibility in brood transport specialisation with no compensatory gain in efficiency

Division of labour is widely thought to increase the task efficiency of eusocial insects. Workers can switch their task to compensate for sudden changes in demand, providing flexible task allocation. In combination with automated tracking technology, we developed a robotic system to precisely control and spatiotemporally manipulate floor temperature over days, which allowed us to predictably drive brood transport behaviour in colonies of the ant Camponotus floridanus. Our results indicate that a small number of workers, usually minors belonging to the nurse social group, are highly specialised for brood transport. There was no difference in the speed at which workers transported brood, suggesting that specialisation does not correlate with efficiency. Workers often started to transport the brood only after having identified a better location. There was no evidence that workers shared information about the presence of a better location. Notably, once brood transporters had been removed, none of the remaining workers performed this task, and the brood transport completely stopped. When brood transporters were returned to their colony, brood transport was immediately restored. Taken together, our study reveals that brood transport is an inflexible task, achieved through the synchronous actions of a few privately informed specialist workers.

A Task Allocation Strategy based on Hungarian Algorithm in RoboCup Rescue Simulation

In the multi-agent cooperation of RoboCup Rescue Agent Simulation, as one of the three agents, the agent with the task of clearing roadblocks plays a significant role. The clearing behavior help other agents to work promptly and provide a highly efficient operation to the entire simulation system. However, considering the cost of all agents in a limited time, it is not easy to carry out flexible task allocation, which leads to the current strategy is not perfect, and finally leads to the low efficiency of rescue operations. Therefore, it is necessary to make sure the high efficiency of clearing behavior. In order to maximize the resources of agents, this article puts forward a task allocation strategy based on Hungarian algorithm, which has substantially enhanced the agents’ efficiency through experimental verification at last.

When being flexible matters: Ecological underpinnings for the evolution of collective flexibility and task allocation

Task allocation is a central feature of collective organization. Living collective systems, such as multicellular organisms or social insect colonies, have evolved diverse ways to allocate individuals to different tasks, ranging from rigid, inflexible task allocation that is not adjusted to changing circumstances to more fluid, flexible task allocation that is rapidly adjusted to the external environment. While the mechanisms underlying task allocation have been intensely studied, it remains poorly understood whether differences in the flexibility of task allocation can be viewed as adaptive responses to different ecological contexts—for example, different degrees of temporal variability. Motivated by this question, we develop an analytically tractable mathematical framework to explore the evolution of task allocation in dynamic environments. We find that collective flexibility is not necessarily always adaptive, and fails to evolve in environments that change too slowly (relative to how long tasks can be left unattended) or too quickly (relative to how rapidly task allocation can be adjusted). We further employ the framework to investigate how environmental variability impacts the internal organization of task allocation, which allows us to propose adaptive explanations for some puzzling empirical observations, such as seemingly unnecessary task switching under constant environmental conditions, apparent task specialization without efficiency benefits, and high levels of individual inactivity. Altogether, this work provides a general framework for probing the evolved diversity of task allocation strategies in nature and reinforces the idea that considering a system’s ecology is crucial to explaining its collective organization.

Learning to Share - Teaching the Impact of Flexible Task Allocation in Human-cobot Teams

Collaborative robots (cobots) are vital for agile concepts of industrial manufacturing and regarded as flexible and low-cost automation solutions. Therefore, learning factory concepts increasingly include handling with cobot technology, their industrial applications and safety concepts. In addition to these fields of knowledge, it is widely considered that work organization at the manufacturing shop floor must be rethought to use the full potential of cobot flexibility. One of the approaches is the flexible task allocation in human-cobot teams. Based on the idea of self-organization, human and cobot tasks are adaptively assessed and optimized. The implementation of this concept enables productivity gains and at the same time reduces negative aspects of automation such as reduced readiness to take action and monotonous work. As this approach requires technological and organizational preconditions as well as prior knowledge of the industrial engineering domain, the paper presents a hands-on educational concept for flexible task allocation in human-cobot teams. Upon an analysis of required competencies and an identification of deficits in existing teaching approaches - based on evaluation criteria such as innovation content, human-cobot team suitability, industrial relevance and reusability - a teaching concept in addition to three hands-on demonstrators was developed. The demonstrators were implemented at the TU Wien Pilot Factory Industry 4.0 allowing for representative task allocation patterns applied in industrial settings. Besides professional educational purposes, the demonstrators can be used for exhibitions as they allow hands-on experiences for the public and therefore contribute to a more realistic perception of the potential, the challenges, and the impact of robots in the manufacturing domain. Thus, working with and evaluating the demonstrators hands-on, not only students and professionals, but also children, teenagers and the general public are able to explore the potential benefits, consequences and necessary preconditions within potential use cases.

Worker propensity affects flexible task reversion in an ant

Social animals exhibit well-organized task allocation among group members. In ants, a large group of eusocial Hymenoptera, the division of labor among workers is maintained by behavioral flexibility, providing robustness against fluctuating environmental conditions. Under stable conditions, worker tasks shift from the inside (e.g., nurses) to the outside (e.g., foragers) of the nest as age increases along this gradient. If the colony’s age structure is unbalanced, some workers compensate for vacant tasks, regardless of their age. However, such behavioral flexibility mechanisms are not clearly described in most ant species. In this study, using the ant Diacamma sp. from Japan, we focused on task reversion (i.e., foragers shifting to nursing roles, reverted nurses). By intermittent observation, we examined how the proportion of trials detected outside the nest of foragers, as foragers’ behavioral propensity, impacts task reversion when caste composition is significantly altered. We revealed that foragers with low proportion were the most likely to become reverted nurses, suggesting that the worker propensity is strongly correlated to task reversion. Moreover, task allocation among workers emerged on day 2 after colony disturbance, suggesting that the division of labor can promptly reconstruct when the age structure of the colony is accidentally altered by external factors. It also illustrates the importance of behavioral propensity in maintaining social systems. We also discussed the mechanisms of flexible task allocation among the workers in terms of self-organized process. In eusocial Hymenoptera (e.g., wasps, honeybees, and ants), the division of labor is maintained by workers’ behavioral flexibility, which is itself driven by the needs of the colony. However, the detailed mechanisms underlying ant behavioral flexibility remain unclear. Focusing on task reversion in foragers shifting to nursing roles regardless of their age-dependent assigned task, we revealed that behavioral propensity strongly affects task reversion in the Diacamma sp. As ant colonies generally have an unbalanced age structure and inhabit unstable environments, behavioral flexibility is thought to be important to maintain the division of labor. Moreover, our study could be applied to examining molecular and physiological basis of task reversion in ant species.

Labour division in swarm intelligence for allocation problems: a survey

Labour division in swarm intelligence provides a flexible task allocation method, which is enlightening to solve allocation problems in dynamic environment. This paper presents a comprehensive survey of labour division in swarm intelligence for allocation problems. Firstly, labour division is stated from the aspects of phenomena, patterns, characteristics and mechanisms, and then four kinds of labour division models, viz., group dynamics model, response threshold model, activator-inhibitor model and individual sorting model, are discussed. Based on the contrastive analysis and typical applications of these models, allocation problems are divided into continuous allocation problems and discrete allocation problems, and the key points of applying the stimulus-response way and the activation-inhibition way to these two types of problems are analysed. Furthermore, the research of labour division in optimisation algorithms and its advantages are discussed. Finally, some perspectives on the development trends of labour division are given as the concluding remarks of this paper.

Flexible task allocation and raid organization in the termite-hunting ant Megaponera analis

Division of labor is one of the main reasons for the success of social insects. Worker polymorphism, age polyethism and work division in more primitive ants, such as the ponerines, remain mostly unexplored. The group hunting, termite-specialist Megaponera analis conducts raids in column formations of 200–500 ants. Since these ants specialize on a defensive prey, adaptations to reduce their foraging costs can be expected. We found that the work division, task allocation and column formation during the hunt were much more sophisticated than was previously thought. The column-formation was remarkably stable, with the same ants resuming similar positions in subsequent raids and front ants even returning to their positions if displaced in the same raid, suggesting yet unknown regulatory mechanisms for the formation of the column. We identified three previously undescribed tasks during the hunting process of M. analis: lingerers, runners and raid-guards. Most of these tasks were not executed by predetermined members of the raid but were filled out as need arose during the hunt, with a clear preference for larger ants to conduct most tasks. The plasticity of task allocation was particularly well exemplified by the termite carriers, with the number of small ants carrying termites only starting to rise when less large ants were available. We, therefore, propose that the continuous allometric size polymorphism in M. analis allows for greater flexibility in task allocation, necessary due to the unpredictability of task requirements in an irregular system such as hunting termites in groups.

Team Incentives and Performance: Evidence from a Retail Chain

We test the effectiveness of team incentives by running a natural field experiment in a retail chain of 193 shops and 1,300 employees. As a response to intensified product market competition, the firm offered a bonus to shop teams for surpassing sales targets. A bonus to teams rather than individuals was a natural choice because the firm does not measure individual performance and relies on flexible task allocation among employees. On average, the team bonus increases sales and customer visits in the treated shops by around 3%, and wages by 2.3%. The bonus is highly profitable for the firm, generating for each bonus dollar an extra $3.80 of sales, and $2.10 of operational profit. The results show the importance of complementarities within teams and suggest that improved operational efficiency is the main mechanism behind the treatment effect. Our analysis of heterogeneous treatment effects offers a number of insights about the anatomy of teamwork. The firm decided to roll out the bonus to all of its shops, and the performance of treatment and control shops converged after the roll-out.

Team Incentives and Performance: Evidence from a Retail Chain

We test the effectiveness of team incentives by running a natural field experiment in a retail chain of 193 shops and 1,300 employees. As a response to intensified product market competition, the firm offered a bonus to shop teams for surpassing sales targets. A bonus to teams rather than individuals was a natural choice because the firm does not measure individual performance and relies on flexible task allocation among employees. On average, the team bonus increases sales and customer visits in the treated shops by around 3%, and wages by 2.3%. The bonus is highly profitable for the firm, generating for each bonus dollar an extra $3.80 of sales, and $2.10 of operational profit. The results show the importance of complementarities within teams and suggest that improved operational efficiency is the main mechanism behind the treatment effect. Our analysis of heterogeneous treatment effects offers a number of insights about the anatomy of teamwork. The firm decided to roll out the bonus to all of its shops, and the performance of treatment and control shops converged after the roll-out.

Exploring payment schemes used to promote integrated chronic care in Europe

The rising burden of chronic conditions has led several European countries to reform healthcare payment schemes. This paper aimed to explore the adoption and success of payment schemes that promote integration of chronic care in European countries. A literature review was used to identify European countries that employed pay-for-coordination (PFC), pay-for-performance (PFP), and bundled payment schemes. Existing evidence from the literature was supplemented with fifteen interviews with chronic care experts in these countries to obtain detailed information regarding the payment schemes, facilitators and barriers to their implementation, and their perceived success.Austria, France, England, the Netherlands, and Germany have implemented payment schemes that were specifically designed to promote the integration of chronic care. Prominent factors facilitating implementation included stakeholder cooperation, adequate financial incentives for stakeholders, and flexible task allocation among different care provider disciplines. Common barriers to implementation included misaligned incentives across stakeholders and gaming. The implemented payment schemes targeted different stakeholders (e.g. individual caregivers, multidisciplinary organizations of caregivers, regions, insurers) in different countries depending on the structure and financing of each health care system. All payment reforms appeared to have changed the structure of chronic care delivery. PFC, as it was implemented in Austria, France and Germany, was perceived to be the most successful in increasing collaboration within and across healthcare sectors, whereas PFP, as it was implemented in England and France, was perceived most successful in improving other indicators of the quality of the care process. Interviewees stated that the impact of the payment reforms on healthcare expenditures remained questionable.The success of a payment scheme depends on the details of the specific implementation in a particular country, but a combination of the schemes may overcome the barriers of each individual scheme.

Flexible task allocation and the organization of work in ants.

Flexibility in task performance is essential for a robust system of division of labour. We investigated what factors determine which social insect workers respond to colony-level changes in task demand. We used radio-frequency identification technology to compare the roles of corpulence, age, spatial location and previous activity (intra-nest/extra-nest) in determining whether worker ants (Temnothorax albipennis) respond to an increase in demand for foraging or brood care. The less corpulent ants took on the extra foraging, irrespective of their age, previous activity or location in the nest, supporting a physiological threshold model. We found no relationship between ants that tended the extra brood and corpulence, age, spatial location or previous activity, but ants that transported the extra brood to the main brood pile were less corpulent and had high previous intra-nest activity. This supports spatial task-encounter and physiological threshold models for brood transport. Our data suggest a flexible task-allocation system allowing the colony to respond rapidly to changing needs, using a simple task-encounter system for generalized tasks, combined with physiologically based response thresholds for more specialized tasks. This could provide a social insect colony with a robust division of labour, flexibly allocating the workforce in response to current needs.

Constructing memory-minimizing schedules for multifrontal methods

We are interested in the memory usage of multifrontal methods. Starting from the algorithms introduced by Liu, we propose new schedules to allocate and process tasks that improve memory usage. This generalizes two existing factorization and memory-allocation schedules by allowing a more flexible task allocation together with a specific tree traversal. We present optimal algorithms for this new class of schedules, and demonstrate experimentally their benefit for some real-world matrices from sparse matrix collections where either the active memory or the total memory is minimized.