1,440 research outputs found
HOW CAN PD PROCESS MODELLING BE MADE MORE USEFUL? AN EXPLORATION OF FACTORS WHICH INFLUENCE MODELLING UTILITY
In what sense is PD process modelling useful? and how can the utility of modelling be improved?
In this paper, we approach these questions through an analysis of PD process modelling ‘utility’ – which in broad terms we consider to be the degree to which a model-based approach or modelling intervention benefits practice. We view the utility of modelling as a composite characteristic which depends both on the properties of models and on the way they are applied. The paper draws upon
established principles of cybernetic systems in an attempt to explain the role played by process modelling in operating and improving PD processes. We use this framework to identify eight key factors which influence the utility of modelling in the context of use. Further, we indicate how these
factors can be interpreted to identify opportunities to improve modelling utility.International Design Conference - DESIGN 201
A cybernetic perspective on methods and process models in collaborative designing
Cybernetic thinking provides a framework to understand the issues in creating and using methods and process models during collaborative designing. It can help understand what takes place while the creation and use is unfolding. This viewpoint allows methods and process models to be framed as aiding human decision-making, and as supporting the organisation of design activities. It casts light on how a team acts and what are they doing to solve design problems, by considering that they react to changes in the perceived solution state or goal state. Cybernetics thus provides an articulation of mechanisms for doing design. By identifying virtues that support creation and use of methods and process models during designing, cybernetics could thus help teams to design more effectively.
This article considers the creation and use of process models and methods in design from a cybernetic perspective. We suggest that a process model and method are similar in nature, in that they both give guidance for progressing the design according to the circumstances encountered. Cybernetic principles are interpreted to help understand the role of modelling and method use in design process evolution.International Design Conference - DESIGN 201
Electrical detection of 31P spin quantum states
In recent years, a variety of solid-state qubits has been realized, including
quantum dots, superconducting tunnel junctions and point defects. Due to its
potential compatibility with existing microelectronics, the proposal by Kane
based on phosphorus donors in Si has also been pursued intensively. A key issue
of this concept is the readout of the P quantum state. While electrical
measurements of magnetic resonance have been performed on single spins, the
statistical nature of these experiments based on random telegraph noise
measurements has impeded the readout of single spin states. In this letter, we
demonstrate the measurement of the spin state of P donor electrons in silicon
and the observation of Rabi flops by purely electric means, accomplished by
coherent manipulation of spin-dependent charge carrier recombination between
the P donor and paramagnetic localized states at the Si/SiO2 interface via
pulsed electrically detected magnetic resonance. The electron spin information
is shown to be coupled through the hyperfine interaction with the P nucleus,
which demonstrates the feasibility of a recombination-based readout of nuclear
spins
New Mechanics of Traumatic Brain Injury
The prediction and prevention of traumatic brain injury is a very important
aspect of preventive medical science. This paper proposes a new coupled
loading-rate hypothesis for the traumatic brain injury (TBI), which states that
the main cause of the TBI is an external Euclidean jolt, or SE(3)-jolt, an
impulsive loading that strikes the head in several coupled degrees-of-freedom
simultaneously. To show this, based on the previously defined covariant force
law, we formulate the coupled Newton-Euler dynamics of brain's micro-motions
within the cerebrospinal fluid and derive from it the coupled SE(3)-jolt
dynamics. The SE(3)-jolt is a cause of the TBI in two forms of brain's rapid
discontinuous deformations: translational dislocations and rotational
disclinations. Brain's dislocations and disclinations, caused by the
SE(3)-jolt, are described using the Cosserat multipolar viscoelastic continuum
brain model.
Keywords: Traumatic brain injuries, coupled loading-rate hypothesis,
Euclidean jolt, coupled Newton-Euler dynamics, brain's dislocations and
disclinationsComment: 18 pages, 1 figure, Late
Predicting Clinical Outcome of Stroke Patients with Tractographic Feature
The volume of stroke lesion is the gold standard for predicting the clinical
outcome of stroke patients. However, the presence of stroke lesion may cause
neural disruptions to other brain regions, and these potentially damaged
regions may affect the clinical outcome of stroke patients. In this paper, we
introduce the tractographic feature to capture these potentially damaged
regions and predict the modified Rankin Scale (mRS), which is a widely used
outcome measure in stroke clinical trials. The tractographic feature is built
from the stroke lesion and average connectome information from a group of
normal subjects. The tractographic feature takes into account different
functional regions that may be affected by the stroke, thus complementing the
commonly used stroke volume features. The proposed tractographic feature is
tested on a public stroke benchmark Ischemic Stroke Lesion Segmentation 2017
and achieves higher accuracy than the stroke volume and the state-of-the-art
feature on predicting the mRS grades of stroke patients. In addition, the
tractographic feature also yields a lower average absolute error than the
commonly used stroke volume feature.Comment: 12 pages, 4 figures, 3 tables. Accepted by MICCAI-BrainLesion 2019 as
an oral presentatio
Long-term follow-up of beryllium sensitized workers from a single employer
<p>Abstract</p> <p>Background</p> <p>Up to 12% of beryllium-exposed American workers would test positive on beryllium lymphocyte proliferation test (BeLPT) screening, but the implications of sensitization remain uncertain.</p> <p>Methods</p> <p>Seventy two current and former employees of a beryllium manufacturer, including 22 with pathologic changes of chronic beryllium disease (CBD), and 50 without, with a confirmed positive test were followed-up for 7.4 +/-3.1 years.</p> <p>Results</p> <p>Beyond predicted effects of aging, flow rates and lung volumes changed little from baseline, while D<sub>L</sub>CO dropped 17.4% of predicted on average. Despite this group decline, only 8 subjects (11.1%) demonstrated physiologic or radiologic abnormalities typical of CBD. Other than baseline status, no clinical or laboratory feature distinguished those who clinically manifested CBD at follow-up from those who did not.</p> <p>Conclusions</p> <p>The clinical outlook remains favorable for beryllium-sensitized individuals over the first 5-12 years. However, declines in D<sub>L</sub>CO may presage further and more serious clinical manifestations in the future. These conclusions are tempered by the possibility of selection bias and other study limitations.</p
Graphene plasmonics
Two rich and vibrant fields of investigation, graphene physics and
plasmonics, strongly overlap. Not only does graphene possess intrinsic plasmons
that are tunable and adjustable, but a combination of graphene with noble-metal
nanostructures promises a variety of exciting applications for conventional
plasmonics. The versatility of graphene means that graphene-based plasmonics
may enable the manufacture of novel optical devices working in different
frequency ranges, from terahertz to the visible, with extremely high speed, low
driving voltage, low power consumption and compact sizes. Here we review the
field emerging at the intersection of graphene physics and plasmonics.Comment: Review article; 12 pages, 6 figures, 99 references (final version
available only at publisher's web site
Two-Particle-Self-Consistent Approach for the Hubbard Model
Even at weak to intermediate coupling, the Hubbard model poses a formidable
challenge. In two dimensions in particular, standard methods such as the Random
Phase Approximation are no longer valid since they predict a finite temperature
antiferromagnetic phase transition prohibited by the Mermin-Wagner theorem. The
Two-Particle-Self-Consistent (TPSC) approach satisfies that theorem as well as
particle conservation, the Pauli principle, the local moment and local charge
sum rules. The self-energy formula does not assume a Migdal theorem. There is
consistency between one- and two-particle quantities. Internal accuracy checks
allow one to test the limits of validity of TPSC. Here I present a pedagogical
review of TPSC along with a short summary of existing results and two case
studies: a) the opening of a pseudogap in two dimensions when the correlation
length is larger than the thermal de Broglie wavelength, and b) the conditions
for the appearance of d-wave superconductivity in the two-dimensional Hubbard
model.Comment: Chapter in "Theoretical methods for Strongly Correlated Systems",
Edited by A. Avella and F. Mancini, Springer Verlag, (2011) 55 pages.
Misprint in Eq.(23) corrected (thanks D. Bergeron
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