88 research outputs found
A Hierarchical Framework Using Approximated Local Outlier Factor for Efficient Anomaly Detection
AbstractAnomaly detection aims to identify rare events that deviate remarkably from existing data. To satisfy real-world appli- cations, various anomaly detection technologies have been proposed. Due to the resource constraints, such as limited energy, computation ability and memory storage, most of them cannot be directly used in wireless sensor networks (WSNs). In this work, we proposed a hierarchical anomaly detection framework to overcome the challenges of anomaly detection in WSNs. We aim to detect anomalies by the accurate model and the approximated model learned at the re- mote server and sink nodes, respectively. Besides the framework, we also proposed an approximated local outlier factor algorithm, which can be learned at the sink nodes. The proposed algorithm is more efficient in computation and storage by comparing with the standard one. Experimental results verify the feasibility of our proposed method in terms of both accuracy and efficiency
Recommended from our members
FAM129B, an antioxidative protein, reduces chemosensitivity by competing with Nrf2 for Keap1 binding.
BackgroundThe transcription factor Nrf2 is a master regulator of antioxidant response. While Nrf2 activation may counter increasing oxidative stress in aging, its activation in cancer can promote cancer progression and metastasis, and confer resistance to chemotherapy and radiotherapy. Thus, Nrf2 has been considered as a key pharmacological target. Unfortunately, there are no specific Nrf2 inhibitors for therapeutic application. Moreover, high Nrf2 activity in many tumors without Keap1 or Nrf2 mutations suggests that alternative mechanisms of Nrf2 regulation exist.MethodsInteraction of FAM129B with Keap1 is demonstrated by immunofluorescence, colocalization, co-immunoprecipitation and mammalian two-hybrid assay. Antioxidative function of FAM129B is analyzed by measuring ROS levels with DCF/flow cytometry, Nrf2 activation using luciferase reporter assay and determination of downstream gene expression by qPCR and wester blotting. Impact of FAM129B on in vivo chemosensitivity is examined in mice bearing breast and colon cancer xenografts. The clinical relevance of FAM129B is assessed by qPCR in breast cancer samples and data mining of publicly available databases.FindingsWe have demonstrated that FAM129B in cancer promotes Nrf2 activity by reducing its ubiquitination through competition with Nrf2 for Keap1 binding via its DLG and ETGE motifs. In addition, FAM129B reduces chemosensitivity by augmenting Nrf2 antioxidative signaling and confers poor prognosis in breast and lung cancer.InterpretationThese findings demonstrate the important role of FAM129B in Nrf2 activation and antioxidative response, and identify FMA129B as a potential therapeutic target. FUND: The Chang Gung Medical Foundation (Taiwan) and the Ministry of Science and Technology (Taiwan)
Shape Effects of Iron Nanowires on Hyperthermia Treatment
This research discusses the influence of morphology of nanomagnetic materials (one-dimensional iron nanowires and zero-dimensional iron nanoparticles) on heating efficiency of the hyperthermia treatment. One-dimensional iron nanowires, synthesized by reducing method in external magnetic field, are explored in terms of their material properties, magnetic anisotropy, and cytotoxicity of EMT-6 cells. The magnetic anisotropy of an array of nanowires is examined in parallel and perpendicular magnetic fields by VSM. For the magnetic hyperthermia treatment tests, iron nanowires and nanoparticles with different concentrations are heated in alternating magnetic field to measure their actual heating efficiency and SLP heating properties. The shape effects of iron nanomaterials can be revealed from their heating properties. The cytotoxicity of nanowires with different concentrations is measured by its survival rate in EMT-6 with the cells cultivated for 6 and 24 hours
Development of a sustained-release voriconazole-containing thermogel for subconjunctival injection in horses
PURPOSE. To determine in vitro release profiles, transcorneal permeation, and ocular injection characteristics of a voriconazole-containing thermogel suitable for injection into the subconjunctival space (SCS). METHODS. In vitro release rate of voriconazole (0.3% and 1.5%) from poly (DL-lactide-coglycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) thermogel was determined for 28 days. A Franz cell diffusion chamber was used to evaluate equine transcorneal and transscleral permeation of voriconazole (1.5% topical solution, 0.3% and 1.5% voriconazole-thermogel) for 24 hours. Antifungal activity of voriconazole released from the 1.5% voriconazole-thermogel was determined via the agar disk diffusion method. Ex vivo equine eyes were injected with liquid voriconazole-thermogel (4°C). Distension of the SCS was assessed ultrasonographically and macroscopically. SCS voriconazole-thermogel injections were performed in a horse 1 week and 2 hours before euthanasia and histopathologic analysis of ocular tissues performed. RESULTS. Voriconazole was released from the PLGA-PEG-PLGA thermogel for more than 21 days in all groups. Release followed first-order kinetics. Voriconazole diffused through the cornea and sclera in all groups. Permeation was greater through the sclerae than corneas. Voriconazole released from the 1.5% voriconazole-thermogel showed antifungal activity in vitro. Voriconazole-thermogel was easily able to be injected into the dorsal SCS where it formed a discrete gel deposit. Voriconazole-thermogel was easily injected in vivo and did not induce any adverse reactions. CONCLUSIONS. Voriconazole-containing thermogels have potential application in treatment of keratomycosis. Further research is required to evaluate their performance in vivo
AMiBA: scaling relations between the integrated Compton-y and X-ray derived temperature, mass, and luminosity
We investigate the scaling relations between the X-ray and the thermal
Sunyaev-Zel'dovich Effect (SZE) properties of clusters of galaxies, using data
taken during 2007 by the Y.T. Lee Array for Microwave Background Anisotropy
(AMiBA) at 94 GHz for the six clusters A1689, A1995, A2142, A2163, A2261, and
A2390. The scaling relations relate the integrated Compton-y parameter Y_{2500}
to the X-ray derived gas temperature T_{e}, total mass M_{2500}, and bolometric
luminosity L_X within r_{2500}. Our results for the power-law index and
normalization are both consistent with the self-similar model and other studies
in the literature except for the Y_{2500}-L_X relation, for which a physical
explanation is given though further investigation may be still needed. Our
results not only provide confidence for the AMiBA project but also support our
understanding of galaxy clusters.Comment: Accepted by ApJ; 8 pages, 3 figures, 5 table
AMiBA Wideband Analog Correlator
A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array
for Microwave Background Anisotropy. Lag correlators using analog multipliers
provide large bandwidth and moderate frequency resolution. Broadband IF
distribution, backend signal processing and control are described. Operating
conditions for optimum sensitivity and linearity are discussed. From
observations, a large effective bandwidth of around 10 GHz has been shown to
provide sufficient sensitivity for detecting cosmic microwave background
variations.Comment: 28 pages, 23 figures, ApJ in press
AMiBA: Broadband Heterodyne CMB Interferometry
The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first
science results on the detection of galaxy clusters via the Sunyaev Zel'dovich
effect. The science objectives required small reflectors in order to sample
large scale structures (20') while interferometry provided modest resolutions
(2'). With these constraints, we designed for the best sensitivity by utilizing
the maximum possible continuum bandwidth matched to the atmospheric window at
86-102GHz, with dual polarizations. A novel wide-band analog correlator was
designed that is easily expandable for more interferometer elements. MMIC
technology was used throughout as much as possible in order to miniaturize the
components and to enhance mass production. These designs will find application
in other upcoming astronomy projects. AMiBA is now in operations since 2006,
and we are in the process to expand the array from 7 to 13 elements.Comment: 10 pages, 6 figures, ApJ in press; a version with high resolution
figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/mtc_highreso.pd
Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations
We present a multiwavelength analysis of a sample of four hot (T_X>8keV)
X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA
Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined
with published X-ray temperatures, to examine the distribution of mass and the
intracluster medium (ICM) in massive cluster environments. Our observations
show that A2261 is very similar to A1689 in terms of lensing properties. Many
tangential arcs are visible around A2261, with an effective Einstein radius
\sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing
measurements implies a mass profile well fitted by an NFW model with a high
concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters.
The cluster A2142 shows complex mass substructure, and displays a shallower
profile (c_{vir} \sim 5), consistent with detailed X-ray observations which
imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature
associated with mass substructure lying ahead of the sharp north-west edge of
the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain
highly elliptical mass and ICM distributions at all radii, consistent with
other X-ray and strong lensing work. Our cluster gas fraction measurements,
free from the hydrostatic equilibrium assumption, are overall in good agreement
with published X-ray and SZE observations, with the sample-averaged gas
fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm
0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction
f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates
/f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing
from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd
The Yuan-Tseh Lee Array for Microwave Background Anisotropy
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the
first interferometer dedicated to studying the cosmic microwave background
(CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the
contributions from foreground synchrotron radiation and Galactic dust emission.
The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod
platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific
operations began with the detection of a number of clusters of galaxies via the
thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing
data in order to study the structure of dark matter. We also compare our data
with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with
high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd
Tests of AMiBA Data Integrity
We describe methods used to validate data from the Y.T. Lee Array for
Microwave Background Anisotropy (AMiBA), an interferometric array designed to
measure the Sunyaev-Zel'dovich effect and the anisotropy of the Cosmic
Microwave Background (CMB). We perform several statistical tests on data from
pointed galaxy cluster observations taken in 2007 and noise data from long-term
blank sky observations and measurements with the feeds covered by the
absorbers. We apply power spectrum analysis, cross power spectrum analysis
among different outputs with different time lags in our analog correlator, and
sample variance law tests to noise data. We find that (1) there is no time
variation of electronic offsets on the time scale of our two-patch observations
(~10 minutes); (2) noise is correlated by less than 10% between different lags;
and (3) the variance of noise scales with the inverse of time. To test the
Gaussianity of the data, we apply Kolmogorov-Smirnov (K-S) tests to cluster
data, and find that a 5% significance level efficiently detects data sets with
known hardware problems without rejecting an excess of acceptable data. We also
calculate third- and fourth-order moments and cumulants for the noise residual
visibilities and find that about 95% of our data are within the 99% confidence
regions of Gaussianity.Comment: 15 pages, 5 figures, accepted for publication in Ap
- …