8 research outputs found
Dynamic Delegation: Shared, Hierarchical, and Deindividualized Leadership in Extreme Action Teams
This paper examines the leadership of extreme action teamsâteams whose highly skilled members cooperate to perform urgent, unpredictable, interdependent, and highly consequential tasks while simultaneously coping with frequent changes in team composition and training their teams\u27 novice members. Our qualitative investigation of the leadership of extreme action medical teams in an emergency trauma center revealed a hierarchical, deindividualized system of shared leadership. At the heart of this system is dynamic delegation: senior leaders\u27 rapid and repeated delegation of the active leadership role to and withdrawal of the active leadership role from more junior leaders of the team. Our findings suggest that dynamic delegation enhances extreme action teams\u27 ability to perform reliably while also building their novice team members\u27 skills. We highlight the contingencies that guide senior leaders\u27 delegation and withdrawal of the active leadership role, as well as the values and structures that motivate and enable the shared, ongoing practice of dynamic delegation. Further, we suggest that extreme action teams and other âimprovisationalâ organizational units may achieve swift coordination and reliable performance by melding hierarchical and bureaucratic role-based structures with flexibility-enhancing processes. The insights emerging from our findings at once extend and challenge prior leadership theory and research, paving the way for further theory development and research on team leadership in dynamic settings
Hierarchical multi-class segmentation of glioma images using networks with multi-level activation function
For many segmentation tasks, especially for the biomedical image, the
topological prior is vital information which is useful to exploit. The
containment/nesting is a typical inter-class geometric relationship. In the
MICCAI Brain tumor segmentation challenge, with its three hierarchically nested
classes 'whole tumor', 'tumor core', 'active tumor', the nested classes
relationship is introduced into the 3D-residual-Unet architecture. The network
comprises a context aggregation pathway and a localization pathway, which
encodes increasingly abstract representation of the input as going deeper into
the network, and then recombines these representations with shallower features
to precisely localize the interest domain via a localization path. The
nested-class-prior is combined by proposing the multi-class activation function
and its corresponding loss function. The model is trained on the training
dataset of Brats2018, and 20% of the dataset is regarded as the validation
dataset to determine parameters. When the parameters are fixed, we retrain the
model on the whole training dataset. The performance achieved on the validation
leaderboard is 86%, 77% and 72% Dice scores for the whole tumor, enhancing
tumor and tumor core classes without relying on ensembles or complicated
post-processing steps. Based on the same start-of-the-art network architecture,
the accuracy of nested-class (enhancing tumor) is reasonably improved from 69%
to 72% compared with the traditional Softmax-based method which blind to
topological prior.Comment: 12pages first versio
Influence of wheel size on muscle activity and tri-axial accelerations during cross-country mountain biking
Dynamic delegation: shared, hierarchical, and deindividualized leadership in extreme action teams
Administrative Science Quarterly, 51(4): pp. 590-621.This paper examines the leadership of extreme action
teamsâteams whose highly skilled members cooperate
to perform urgent, unpredictable, interdependent, and
highly consequential tasks while simultaneously coping
with frequent changes in team composition and training
their teamsâ novice members. Our qualitative investigation
of the leadership of extreme action medical teams in
an emergency trauma center revealed a hierarchical,
deindividualized system of shared leadership. At the
heart of this system is dynamic delegation: senior leadersâ
rapid and repeated delegation of the active leadership
role to and withdrawal of the active leadership role
from more junior leaders of the team. Our findings suggest
that dynamic delegation enhances extreme action
teamsâ ability to perform reliably while also building their
novice team membersâ skills. We highlight the contingencies
that guide senior leadersâ delegation and withdrawal
of the active leadership role, as well as the values and
structures that motivate and enable the shared, ongoing
practice of dynamic delegation. Further, we suggest that
extreme action teams and other âimprovisationalâ organizational
units may achieve swift coordination and reliable
performance by melding hierarchical and bureaucratic
role-based structures with flexibility-enhancing
processes. The insights emerging from our findings at
once extend and challenge prior leadership theory and
research, paving the way for further theory development
and research on team leadership in dynamic settings