914 research outputs found
Machine tool process monitoring by segmented timeseries anomaly detection using subprocess-specific thresholds
Time series data generated by manufacturing machines during processing is widely used in mass part production to assess if processes run without errors. Systems that make use of this data use machine learning approaches for flagging a time series as a deviation from normal behaviour. In single part production, the amount of data generated is not sufficient for learning-based classification. Here, methods often focus on global signal variance but have trouble finding anomalies that present as local signal deviations. The referencing of the process states of the machine is usually performed by state indexing which, however, is not sufficient in highly flexible production plants. In this paper, a system that learns granular patterns in time series based on mean shift clustering is used for detecting processing segments in varying machine conditions. An anomaly detection then finds deviating patterns based on the previously identified processing segments. The anomalies can then be labeled by a human-in-the-loop approach for enabling future anomaly classification using a combination of machine learning algorithms. The method of anomaly detection is validated using an industrial machine tool and multiple test series
Complicating Decisions: The Work Ethic Heuristic and the Construction of Effortful Decisions
The notion that effort and hard work yield desired outcomes is ingrained in many cultures and affects our thinking and behavior. However, could valuing effort complicate our lives? In the present article, the authors demonstrate that individuals with a stronger tendency to link effort with positive outcomes end up complicating what should be easy decisions. People distort their preferences and the information they search and recall in a manner that intensifies the choice conflict and decisional effort they experience before finalizing their choice. Six experiments identify the effort-outcome link as the underlying mechanism for such conflict-increasing behavior. Individuals with a stronger tendency to link effort with positive outcomes (e.g., individuals who subscribe to a Protestant Work Ethic) are shown to complicate decisions by: (a) distorting evaluations of alternatives (Study 1); (b) distorting information recalled about the alternatives (Studies 2a and 2b); and (3) distorting interpretations of information about the alternatives (Study 3). Further, individuals conduct a superfluous search for information and spend more time than needed on what should have been an easy decision (Studies 4a and 4b)
Structural and vibrational properties of two-dimensional nanolayers on Pd(100)
Using different experimental techniques combined with density functional
based theoretical methods we have explored the formation of
interface-stabilized manganese oxide structures grown on Pd(100) at
(sub)monolayer coverage. Amongst the multitude of phases experimentally
observed we focus our attention on four structures which can be classified into
two distinct regimes, characterized by different building blocks. Two
oxygen-rich phases are described in terms of MnO(111)-like O-Mn-O trilayers,
whereas the other two have a lower oxygen content and are based on a
MnO(100)-like monolayer structure. The excellent agreement between calculated
and experimental scanning tunneling microscopy images and vibrational electron
energy loss spectra allows for a detailed atomic description of the explored
models.Comment: 14 pages, 11 figure
X-ray Properties of the Weak Seyfert 1 Nucleus in NGC 4639
We obtained observations of NGC 4639 with ASCA in order to investigate its
mildly active Seyfert 1 nucleus at hard X-ray energies. Koratkar et al. (1995)
have previously shown that the nucleus is a pointlike source in the ROSAT soft
X-ray band. We detected in the 2-10 keV band a compact central source with a
luminosity of 8.3E+40 erg/s. Comparison of the ASCA data with archival data
taken with the Einstein and ROSAT satellites shows that the nucleus varies on
timescales of months to years. The variability could be intrinsic, or it could
be caused by variable absorption. More rapid variability, on a timescale of
\~10^4 s, may be present in the ASCA data. The spectrum from 0.5 to 10 keV is
well described by a model consisting of a lightly absorbed (N_H = 7.3E+20
cm^-2) power law with a photon index of 1.68. We find no evidence for
significant emission from a thermal plasma; if present, it can account for no
more than 25% of the flux in the 0.5-2.0 keV band. The limited photon
statistics of our data do not allow us to place significant limits on the
presence of iron K emission. (abridged)Comment: To appear in The Astrophysical Journal. LaTex, 18 pages including
embedded figures and table
The X-ray Emission from the Nucleus of the Dwarf Elliptical Galaxy NGC 3226
We present the first high resolution X-ray image of the dwarf elliptical
galaxy NGC 3226. The data were obtained during an observation of the nearby
Seyfert Galaxy NGC 3227 using the Chandra X-ray Observatory. We detect a point
X-ray source spatially consistent with the optical nucleus of NGC 3226 and a
recently-detected, compact, flat-spectrum, radio source. The X-ray spectrum can
be measured up to ~10 keV and is consistent with a power law with a photon
index 1.7 <~ Gamma <~ 2.2, or thermal bremmstrahlung emission with 4 <~ kT <~
10 keV. In both cases the luminosity in the 2--10 keV band ~10^{40} h_{75}^{-1}
erg/s. We find marginal evidence that the nucleus varies within the
observation. These characteristics support evidence from other wavebands that
NGC 3226 harbors a low-luminosity, active nucleus. We also comment on two
previously-unknown, fainter X-ray sources <~ 15 arcsec from the nucleus of NGC
3226. Their proximity to the nucleus (with projected distances <~ 1.3/h_{75}
kpc) suggests both are within NGC 3226, and thus have luminosities (~few x
10^{38} -- few x 10^{39} erg/s) consistent with black-hole binary systems.Comment: Accepted for publication in ApJ. Figures in colo
Accretion Properties of A Sample of Hard X-ray (<60keV) Selected Seyfert 1 Galaxies
We examine the accretion properties in a sample of 42 hard (3-60keV) X-ray
selected nearby broad-line AGNs. The energy range in the sample is harder than
that usually used in the similar previous studies. These AGNs are mainly
complied from the RXTE All Sky Survey (XSS), and complemented by the released
INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN,
and Eddington ratios are derived from their optical spectra in terms of the
broad H emission line. The tight correlation between the hard X-ray
(3-20keV) and bolometric/line luminosity is well identified in our sample. Also
identified is a strong inverse Baldwin relationship of the H emission
line. In addition, all these hard X-ray AGNs are biased toward luminous objects
with high Eddington ratio (mostly between 0.01 to 0.1) and low column density
(), which is most likely due to the selection effect
of the surveys. The hard X-ray luminosity is consequently found to be strongly
correlated with the black hole mass. We believe the sample completeness will be
improved in the next few years by the ongoing Swift and INTEGRAL missions, and
by the next advanced missions, such as NuSTAR, Simbol-X, and NeXT. Finally, the
correlation between RFe (=optical FeII/H) and disk temperature as
assessed by leads us to
suggest that the strength of the FeII emission is mainly determined by the
shape of the ionizing spectrum.Comment: 28 pages, 7 figures, 2 tables, accepted by A
Implications from the optical to UV flux ratio of FeII emission in quasars
We investigate FeII emission in Broad Line Region (BLR) of AGNs by analyzing
the FeII(UV), FeII(4570) and MgII emission lines in 884 quasars in the Sloan
Digital Sky Survey (SDSS) Quasar catalog in a redshift range of 0.727 < z <
0.804. FeII(4570)/FeII(UV) is used to infer the column density of FeII-emitting
clouds and explore the excitation mechanism of FeII emission lines. As
suggested before in various works, the classical photoionization models fail to
account for FeII(4570)/FeII(UV) by a factor of 10, which may suggest anisotropy
of UV FeII emission; otherwise, an alternative heating mechanism like shock is
working. The column density distribution derived from FeII(4570)/FeII(UV)
indicates that radiation pressure plays an important role in BLR gas dynamics.
We find a positive correlation between FeII(4570)/FeII(UV) and the Eddington
ratio. We also find that almost all FeII-emitting clouds are to be under
super-Eddington conditions unless ionizing photon fraction is much smaller than
that previously suggested. Finally we propose a physical interpretation of a
striking set of correlations between various emission-line properties, known as
``Eigenvector 1''.Comment: 10 pages, 10 figures, accepted for publication in MNRA
An early resource characterization of deep learning on wearables, smartphones and internet-of-things devices
Detecting and reacting to user behavior and ambient context are core elements of many emerging mobile sensing and Internet-of-Things (IoT) applications. However, extracting accurate infer-ences from raw sensor data is challenging within the noisy and complex environments where these systems are deployed. Deep Learning { is one of the most promising approaches for overcom-ing this challenge, and achieving more robust and reliable infer-ence. Techniques developed within this rapidly evolving area of machine learning are now state-of-the-art for many inference tasks (such as, audio sensing and computer vision) commonly needed by IoT and wearable applications. But currently deep learning al-gorithms are seldom used in mobile/IoT class hardware because they often impose debilitating levels of system overhead (e.g., memory, computation and energy). Efforts to address this bar-rier to deep learning adoption are slowed by our lack of a system-atic understanding of how these algorithms behave at inference time on resource constrained hardware. In this paper, we present the-rst { albeit preliminary { measurement study of common deep learning models (such as Convolutional Neural Networks and Deep Neural Networks) on representative mobile and embed-ded platforms. The aim of this investigation is to begin to build knowledge of the performance characteristics, resource require-ments and the execution bottlenecks for deep learning models when being used to recognize categories of behavior and context. The results and insights of this study, lay an empirical foundation for the development of optimization methods and execution envi-ronments that enable deep learning to be more readily integrated into next-generation IoT, smartphones and wearable systems
Risk Factors for the Development of Cataract in Children with Uveitis
PURPOSE:
To determine the risk factors for the development of cataract in children with uveitis of any etiology.
DESIGN:
Cohort study.
METHODS:
Two hundred forty-seven eyes of 140 children with uveitis were evaluated for the development of vision-affecting cataract. Demographic, clinical, and treatment data were collected between the time of presentation and the first instance cataract was recorded or findings at final follow-up. Main outcome measures included the prevalence of cataract and distribution by type of uveitis, incidence of new onset cataract time to cataract development, and risk factors for the development of cataract.
RESULTS: The prevalence of cataract in our cohort was 44.2% and was highest among eyes with panuveitis (77.1%), chronic anterior uveitis (48.3%), and intermediate uveitis (48.0%). The overall incidence of newly diagnosed cataract was 0.09 per eye-year, with an estimated 69% to develop uveitis-related cataract with time. The main factors related with cataract development were the number of uveitis flares per year (hazard ratio [HR] = 3.06 [95% confidence interval {CI}, 2.15–4.35], P < .001), cystoid macular edema (HR = 2.87 [95% CI, 1.41–5.82], P = .004), posterior synechia at presentation (HR = 2.85 [95% CI, 1.53–5.30], P = .001), and use of local injections of corticosteroids (HR = 2.37 [95% CI, 1.18–4.75], P = .02). Treatments with systemic and topical corticosteroids were not significant risk factors.
CONCLUSIONS:
In this study, we found that development of cataract is common among pediatric eyes with uveitis and is most strongly related to the extent of inflammation recurrences and ocular complications. We suggest that controlling the inflammation, even using higher doses of systemic and topical corticosteroids, is of importance in preventing ocular complications, such as cataract.
Uveitis accounts for 10–15% of blindness in the developed world.1 Although pediatric uveitis is relatively uncommon, accounting for only 5–10% of all uveitis cases,2 it affects young patients, who in most cases are otherwise healthy. Vision loss results from ongoing inflammation that leads to ocular structural changes, such as cataract, corneal opacities, optic neuropathy, and retinal lesions. The most common causes of vision loss in children with uveitis are cataract, glaucoma, and chronic cystoid macular edema (CME).2, 3 In addition, any chronic visual obstruction can result in the development of amblyopia in younger children, with vision loss persisting after the inciting cause is treated.4 Such changes, together with the need for long-term treatment and continuous monitoring, can have a profound impact on their development, independence, and education.
The prevalence of cataract in eyes with uveitis ranges from 20–64%,4, 5, 6, 7 and it is the most common complication of uveitis in children,8 occurring in approximately 35% of children with juvenile idiopathic arthritis (JIA)-associated uveitis9 and increasing ≤80% in adults.10, 11 Cataract progression can be the result of persistent intraocular inflammation,12, 13 can be caused by surgery for uveitis complications (eg, trabeculectomies and repair of retinal detachments), or can be a consequence of uveitis treatment, particularly the use of local or systemic corticosteroids.14, 15, 16, 17 It results in reduced visual acuity and can have a detrimental effect on the development and academic achievements of these children.18
Studies have examined risk factors for the development of cataract among children with JIA-associated uveitis, identifying risk factors such as the presence of posterior synechiae (PS) at presentation,12, 19 the use of systemic corticosteroids,13 topical corticosteroid therapy exceeding 3 drops a day,12 or persistent, uncontrolled active inflammation,3 while early treatment with methotrexate delayed cataract progression.19 However, JIA is a unique cause of uveitis, often localized to the anterior chamber, with frequent intraocular structural changes and the early use of systemic immunosuppressive agents. It may not represent the same risks as other causes of pediatric uveitis.
We examined disease- and treatment-related risk factors for cataract development in children with uveitis of any etiology. We investigated clinical and ophthalmologic characteristics, as well as treatment strategies in relation to the time interval between the first presentation with uveitis and cataract development
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