5,279 research outputs found
A Method for Visualizing the Structural Complexity of Organizational Architectures
To achieve a high level of performance and efficiency, contemporary aerospace systems must become increasingly complex. While complexity management traditionally focuses on a product’s components and their interconnectedness, organizational representation in complexity analysis is just as essential. This thesis addresses this organizational aspect of complexity through an Organizational Complexity Metric (OCM) to aid complexity management. The OCM augments Sinha’s structural complexity metric for product architectures into a metric that can be applied to organizations. Utilizing nested numerical design structure matrices (DSMs), a compact visual representation of organizational complexity was developed. Within the nested numerical DSM are existing organizational datasets used to quantify the complexity of both organizational system components and their interfaces. The OCM was applied to a hypothetical system example, as well as an existing aerospace organizational architecture. Through the development of the OCM, this thesis assumed that each dataset was collected in a statistically sufficient manner and has a reasonable correlation to system complexity. This thesis recognizes the lack of complete human representation and aims to provide a platform for expansion. Before a true organizational complexity metric can be applied to real systems, additional human considerations should be considered. These limitations differ from organization to organization and should be taken into consideration before implementation into a working system. The visualization of organizational complexity uses a color gradient to show the relative complexity density of different parts of the organization
Qubit Channels Can Require More Than Two Inputs to Achieve Capacity
We give examples of qubit channels that require three input states in order
to achieve the Holevo capacity.Comment: RevTex, 5 page, 4 figures
Stages of Habitat Structural Trend That are Related to Ungulate Browsing
To maintain their structural identity, communities of tall-growing trees and shrubs depend on the growth of young plants to replace mature individuals that die. Ungulate browsing influences that structure by permitting or preventing the height growth of young plants. The resulting changes in structure are indicted by the browsing-related architectures of plants that grow within the browse zone, i.e., those ? 2.5 m tall. Using examples from six National Wildlife Refuges, we describe six stages of structural trend and their management implications: 1) Structure is Stable, i.e., all plants have Uninterrupted-growthtype architecture; 2) Early Stage of Structural Decline most or all plants have Arrested- or Retrogressed-type architecture and there is no visible evidence of dieback; 3) Intermediate Stage of Structural Decline, i.e., all plants have Arrested- or Retrogressed-type architecture, dieback is apparent, and live stems extend throughout the lower half of the browse zone; 4) Advanced Stage of Decline, i.e., all plants have Arrested- or Retrogressed-type architecture and live stems are restricted to the lowest part of the browse zone; 5) Structure is Lost, i.e., no live plants; and 6) Recovery of Structural Diversity, i.e., there is evidence that the Early, Intermediate, or Advanced Stage of Decline existed, and that young Uninterrupted-growth type plants are growing into the browse zone. Three factors influence the rate-of-change from one stage to another: Susceptibility, Resistance, and Resilience. Because the stages are independent of species composition, they provide a means of comparing the effect of browsing in diverse habitats across a region
Rapid flow fractionation of particles combining liquid and particulate dielectrophoresis
Rapid, size-based, deposition of particles from liquid suspension is accomplished using a nonuniform electric field created by coplanar microelectrode strips patterned on an insulating substrate. The scheme uses the dielectrophoretic force both to distribute aqueous liquid containing particles and, simultaneously, to separate the particles. Size-based separation is found within nanoliter droplets formed along the structure after voltage removal. Bioparticles or macromolecules of similar size can also be separated based on subtle differences in dielectric property, by controlling the frequency of the AC current supplied to the electrodes
The Space Motion of the Globular Cluster NGC 6397
As a by-product of high-precision, ultra-deep stellar photometry in the
Galactic globular cluster NGC 6397 with the Hubble Space Telescope, we are able
to measure a large population of background galaxies whose images are nearly
point-like. These provide an extragalactic reference frame of unprecedented
accuracy, relative to which we measure the most accurate absolute proper motion
ever determined for a globular cluster. We find mu_alpha = 3.56 +/- 0.04 mas/yr
and mu_delta = -17.34 +/- 0.04 mas/yr. We note that the formal statistical
errors quoted for the proper motion of NGC 6397 do not include possible
unavoidable sources of systematic errors, such as cluster rotation. These are
very unlikely to exceed a few percent. We use this new proper motion to
calculate NGC 6397's UVW space velocity and its orbit around the Milky Way, and
find that the cluster has made frequent passages through the Galactic disk.Comment: 5 pages including 3 figures, accepted for publication in the
Astrophysical Journal Letters. Very minor changes in V2. typos fixe
The White Dwarf Cooling Sequence of NGC6397
We present the results of a deep Hubble Space Telescope (HST) exposure of the
nearby globular cluster NGC6397, focussing attention on the cluster's white
dwarf cooling sequence. This sequence is shown to extend over 5 magnitudes in
depth, with an apparent cutoff at magnitude F814W=27.6. We demonstrate, using
both artificial star tests and the detectability of background galaxies at
fainter magnitudes, that the cutoff is real and represents the truncation of
the white dwarf luminosity function in this cluster. We perform a detailed
comparison between cooling models and the observed distribution of white dwarfs
in colour and magnitude, taking into account uncertainties in distance,
extinction, white dwarf mass, progenitor lifetimes, binarity and cooling model
uncertainties. After marginalising over these variables, we obtain values for
the cluster distance modulus and age of \mu_0 = 12.02 \pm 0.06 and T_c = 11.47
\pm 0.47Gyr (95% confidence limits). Our inferred distance and white dwarf
initial-final mass relations are in good agreement with other independent
determinations, and the cluster age is consistent with, but more precise than,
prior determinations made using the main sequence turnoff method. In
particular, within the context of the currently accepted \Lambda CDM
cosmological model, this age places the formation of NGC6397 at a redshift z=3,
at a time when the cosmological star formation rate was approaching its peak.Comment: 56 pages, 30 figure
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Mass casualty events: what to do as the dust settles?
Care during mass casualty events (MCE) has improved during the last 15 years. Military and civilian collaboration has led to partnerships which augment the response to MCE. Much has been written about strategies to deliver care during an MCE, but there is little about how to transition back to normal operations after an event. A panel discussion entitled The Day(s) After: Lessons Learned from Trauma Team Management in the Aftermath of an Unexpected Mass Casualty Event at the 76th Annual American Association for the Surgery of Trauma meeting on September 13, 2017 brought together a cadre of military and civilian surgeons with experience in MCEs. The events described were the First Battle of Mogadishu (1993), the Second Battle of Fallujah (2004), the Bagram Detention Center Rocket Attack (2014), the Boston Marathon Bombing (2013), the Asiana Flight 214 Plane Crash (2013), the Baltimore Riots (2015), and the Orlando Pulse Night Club Shooting (2016). This article focuses on the lessons learned from military and civilian surgeons in the days after MCEs
Comparisons of Temporal and Spatial Trends in the Spatially Complete Global Spectral Surface Albedos Products
Five years of spatially complete snow-free land surface albedo data have been prepared using high quality white-sky and black-sky land surface albedo observations (MOD43B3) from the MODIS instrument aboard NASA's Terra satellite platform. The data were generated using an updated ecosystem-dependent temporal interpolation technique. In this paper, we describe the refinements in the technique and the creation of a spatially complete snow-free five-year aggregate climatology product. This paper also describes an error analysis of the interpolation technique. The filled albedo products are examined through comparisons of temporal and spatial trends for pixels that have been filled versus pixels that have been retained in the original MOD43B3 values. The variability in the trends showcase how the filling technique maintains the pixel-level spatial, spectral, and temporal integrity of the MOD43B3 data. These comparisons are made for both a single-year of filled data, year 2002, and for the five-year aggregate climatology product
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