11,289 research outputs found
Analysis and control of complex collaborative design systems
This paper presents a novel method for modelling the complexity of collaborative design systems based on its analysis and proposes a solution to reducing complexity and improving performance of such systems. The interaction and interfacing properties among many components of a complex design system are analysed from different viewpoints and then a complexity model for collaborative design is established accordingly. In order to simplify complexity and improve performance of collaborative design, a general solution of decomposing a whole system into sub-systems and using unified interface mechanism between them has been proposed. This proposed solution has been tested with a case study. It has been shown that the proposed solution is meaningful and practical
Critical Landscape Planning during the Belt and Road Initiative
This open access book traces the development of landscapes along the 414-kilometer ChinaâLaos Railway, one of the first infrastructure projects implemented under Chinaâs Belt and Road Initiative (BRI) and which is due for completion at the end of 2021. Written from the perspective of landscape architecture and intended for planners and related professionals engaged in the development and conservation of these landscapes, this book provides history, planning pedagogy and interdisciplinary framing for working alongside the often-opaque planning, design and implementation processes of large-scale infrastructure. It complicates simplistic notions of development and urbanization frequently reproduced in the LaosâChina frontier region. Many of the projects and sites investigated in this book are recent âfirstsâ in Laos: Laosâs first wildlife sanctuary for trafficked endangered species, its first botanical garden and its first planting plan for a community forest. Most often the agents and accomplices of neoliberal development, the planning and design professions, including landscape architecture, have little dialogue with either the mainstream natural sciences or critical social sciences that form the discourse of projects in Laos and comparable contexts. Covering diverse conceptions and issues of development, including cultural and scientific knowledge exchanges between Laos and China, nature tourism, connectivity and new town planning, this book also features nine planning proposals for Laos generated through this research initiative since the railway's groundbreaking in 2016. Each proposal promotes a wider "landscape approach" to development and deploys landscape architectureâs spatial and ecological acumen to synthesize critical development studies with the planner's capacity, if not naive predilection, to intervene on the ground. Ultimately, this book advocates the cautious engagement of the professionally oriented built-environment disciplines, such as regional planning, civil engineering and landscape architecture, with the landscapes of development institutions and environmental NGOs
Sensory filtering disruption caused by poly I:C - Timing of exposure and other experimental considerations.
Maternal immune activation (MIA) in response to infection during pregnancy has been linked through various epidemiological and preclinical studies to an increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD) and schizophrenia in exposed offspring. Sensory filtering disruptions occur in both of these disorders and are typically measured using the acoustic startle response in both humans and rodents. Our study focuses on characterizing the baseline reactivity, habituation and prepulse inhibition (PPI) of the acoustic startle response following exposure to MIA. We induced MIA using polyinosinic: polycytidylic acid (poly I:C) at gestational day (GD) 9.5 or 14.5, and we tested sensory filtering phenotypes in adolescent and adult offspring. Our results show that startle reactivity was robustly increased in adult GD9.5 but not GD14.5 poly I:C offspring. In contrast to some previous studies, we found no consistent changes in short-term habituation, long-term habituation or prepulse inhibition of startle. Our study highlights the importance of MIA exposure timing and discusses sensory filtering phenotypes as they relate to ASD, schizophrenia and the poly I:C MIA model. Moreover, we analyze and discuss the potential impact of between- and within-litter variability on behavioural findings in poly I:C studies
Scalar and vector form factors of the in-medium nucleon
Using the quark-meson coupling model, we calculate the form factors at sigma-
and omega-nucleon strong-interaction vertices in nuclear matter. The
Peierls-Yoccoz projection technique is used to take account of center of mass
and recoil corrections. We also apply the Lorentz contraction to the internal
quark wave function. The form factors are reduced by the nuclear medium
relative to those in vacuum. At normal nuclear matter density and Q^2 = 1
GeV^2, the reduction rate in the scalar form factor is about 15%, which is
almost identical to that in the vector one. We parameterize the ratios of the
form factors in symmetric nuclear matter to those in vacuum as a function of
nuclear density and momentum transfer.Comment: 13 pages, 2 figures, references are up date
Concave Switching in Single and Multihop Networks
Switched queueing networks model wireless networks, input queued switches and
numerous other networked communications systems. For single-hop networks, we
consider a {()-switch policy} which combines the MaxWeight policies
with bandwidth sharing networks -- a further well studied model of Internet
congestion. We prove the maximum stability property for this class of
randomized policies. Thus these policies have the same first order behavior as
the MaxWeight policies. However, for multihop networks some of these
generalized polices address a number of critical weakness of the
MaxWeight/BackPressure policies.
For multihop networks with fixed routing, we consider the Proportional
Scheduler (or (1,log)-policy). In this setting, the BackPressure policy is
maximum stable, but must maintain a queue for every route-destination, which
typically grows rapidly with a network's size. However, this proportionally
fair policy only needs to maintain a queue for each outgoing link, which is
typically bounded in number. As is common with Internet routing, by maintaining
per-link queueing each node only needs to know the next hop for each packet and
not its entire route. Further, in contrast to BackPressure, the Proportional
Scheduler does not compare downstream queue lengths to determine weights, only
local link information is required. This leads to greater potential for
decomposed implementations of the policy. Through a reduction argument and an
entropy argument, we demonstrate that, whilst maintaining substantially less
queueing overhead, the Proportional Scheduler achieves maximum throughput
stability.Comment: 28 page
The Effectiveness of Reciprocal Scaffolding Treatment in Anomic Aphasia
Reciprocal Scaffolding Treatment (RST) uses an apprenticeship model of learning that occurs between novices and a skilled partner. This project examined the effect of RST on improvement of word retrieval and conversational content for an individual with anomic aphasia. Novices were graduate student clinicians and the skilled partner was an individual with aphasia, who demonstrated facilitative communication techniques during conversational group treatment conducted by the novices. The individual with aphasia made positive changes in word fluency, correct information units and type-token ratio. Novice clinicians acquired training in facilitating conversational skills from a knowledgeable individual with aphasia
The FRIGG project: From intermediate galactic scales to self-gravitating cores
Abridged. Understanding the detailed structure of the interstellar gas is
essential for our knowledge of the star formation process. The small-scale
structure of the interstellar medium (ISM) is a direct consequence of the
galactic scales and making the link between the two is essential. We perform
adaptive mesh simulations that aim to bridge the gap between the intermediate
galactic scales and the self-gravitating prestellar cores. For this purpose we
use stratified supernova regulated ISM magneto-hydrodynamical (MHD) simulations
at the kpc scale to set up the initial conditions. We then zoom, performing a
series of concentric uniform refinement and then refining on the Jeans length
for the last levels. This allows us to reach a spatial resolution of a few
pc. The cores are identified using a clump finder and various
criteria based on virial analysis. Their most relevant properties are computed
and, due to the large number of objects formed in the simulations, reliable
statistics are obtained. The cores properties show encouraging agreements with
observations. The mass spectrum presents a clear powerlaw at high masses with
an exponent close to and a peak at about 1-2 . The
velocity dispersion and the angular momentum distributions are respectively a
few times the local sound speed and a few pc km s. We also
find that the distribution of thermally supercritical cores present a range of
magnetic mass-to-flux over critical mass-to-flux ratio which typically ranges
between 0.3 and 3.Comment: accepted for publication in A&
Hard X-ray photon index as an indicator of bolometric correction in active galactic nuclei
We propose the rest-frame 2-10 keV photon index, \ga, acting as an indicator
of the bolometric correction, \lb/ (where \lb~ is the
bolometric luminosity and is the rest-frame 2-10 keV
luminosity), in radio-quiet active galactic nuclei (AGNs). Correlations between
\ga~ and both bolometric correction and Eddington ratio are presented, based on
simultaneous X-ray, UV, and optical observations of reverberation -mapped AGNs.
These correlations can be compared with those for high-redshift AGNs to check
for any evolutionary effect. Assuming no evolutionary effect in AGNs' spectral
properties, together with the independent estimates of , the
bolometric correction, Eddington ratio, and black hole (BH) mass can all be
estimated from these correlations for high-redshift AGNs, with the mean
uncertainty of a factor of 2-3. If there are independent estimates of BH
masses, \ga~ for high-redshift AGNs can be used to determine their true \lb~
and , and in conjunction with the redshift, can be potentially
used to place constraints on cosmology by comparison with the rest-frame 2-10
keV flux. We find that the true estimated from \ga~ for the
brightest Type I AGNs with in the Lockman Hole is generally in agreement
with the observed .
However, there are still many uncertainties, such as the accurate
determination of the intrinsic \ga~ for distant AGNs and the large uncertainty
in the luminosities obtained, which call for significant further study before
``AGN cosmology'' can be considered a viable technique.Comment: 2 figures, accepted for publication in the ApJ Lette
SYSTEM AND METHOD FOR FABRICATING POLARIZATION SELECTIVE ELEMENT
A system includes a surface relief grating configured to forwardly diffract an input beam as two linearly polarized beams. The system also includes a waveplate optically coupled with the surface relief grating and configured to convert the two linearly polarized beams into two circularly polarized beams having orthogonal circular polarizations. The two circularly polarized beams having orthogonal circular polarizations interfere with one another to generate a polarization interference pattern
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