1,138 research outputs found
Automated optical inspection of solder paste based on 2.5D visual images
In this paper, a special technique for the inspection of solder paste using directional LED lighting is presented. Conventional optical inspection method would depend on an image acquired from a camera mounted from the top. This 2D inspection of solder paste based on images is fast but is limited to defect such as bridge or no solder. Defects related to the volume of the printed solder paste or unevenness of the paste cannot be treated from a top image. The developed technique of this paper would involve the use of special directional side lighting to acquire two-and-a-half dimensional (2.5D) images from above the solder paste block. A sequence of three images is acquired and image processing is carried out for defect detection of the printed solder paste. The acquired images would highlight the geometrical features of the solder paste block. Solder paste inspection is then carried out based on the highlighted features. The proposed method can handle other types of defects that cannot be treated by conventional top light images. ©2009 IEEE.published_or_final_versio
Route selection for vehicle navigation and control
This paper presents an application of neural-fuzzy methodology for the problem of route selection in a typical vehicle navigation and control system. The idea of the primary attributes of a route is discussed, and a neural-fuzzy system is developed to help a user to select a route out of the many possible routes from an origin to the destination. The user may not adopt the recommendation provided by the system and choose an alternate route. One novel feature of the system is that the neural-fuzzy system can adapt itself by changing the weights of the defined fuzzy rules through a training procedure. Two examples are given in this paper to illustrate how the route selection/ranking system can be made adaptive to the past choice or preference of the user. ©2007 IEEE.published_or_final_versio
Spanning "Bleeding" Boundaries: Humanitarianism, NGOs, and the Civilian-Military Nexus in the Post-Cold War Era
How do nongovernmental (NGO), international (IO),
and military organizations cope with their dependencies
and address their perceptual and real diff erences in
order to coordinate their fi eld operations? Th is question
is addressed through the creation of a matrix grouping
civilian (NGOs and IOs) and military operations into
four general types: peacekeeping; disaster relief; complex
humanitarian emergencies/warfare; and stabilization
and reconstruction. Second, using Galbraith’s
information processing approach to organizational
design, a range of formal coordination mechanisms
that organizations use at the strategic and operational
levels to help them cope with their dependencies in
diff erent fi eld operations is identifi ed. Th ird, the author
underscores how communities of practice are emerging
as informal mechanisms of coordination among civilian
and military organizations. And fi nally, a framework of
organizational forms that views communities of practice
as an alternative to hierarchy and markets is off ered.
Believing communities of practice hold the most promise
for coordination in the human security domain when
hierarchies are politically untenable and markets lack
accountability, the author concludes with implications for
interorganization coordination research and practice
A γA-Crystallin Mouse Mutant Secc with Small Eye, Cataract and Closed Eyelid
published_or_final_versio
Thermodynamics of Dyonic Lifshitz Black Holes
Black holes with asymptotic anisotropic scaling are conjectured to be gravity
duals of condensed matter system close to quantum critical points with
non-trivial dynamical exponent z at finite temperature. A holographic
renormalization procedure is presented that allows thermodynamic potentials to
be defined for objects with both electric and magnetic charge in such a way
that standard thermodynamic relations hold. Black holes in asymptotic Lifshitz
spacetimes can exhibit paramagnetic behavior at low temperature limit for
certain values of the critical exponent z, whereas the behavior of AdS black
holes is always diamagnetic.Comment: 26 pages, 4 figure
Gauss-Bonnet Black Holes and Heavy Fermion Metals
We consider charged black holes in Einstein-Gauss-Bonnet Gravity with
Lifshitz boundary conditions. We find that this class of models can reproduce
the anomalous specific heat of condensed matter systems exhibiting
non-Fermi-liquid behaviour at low temperatures. We find that the temperature
dependence of the Sommerfeld ratio is sensitive to the choice of Gauss-Bonnet
coupling parameter for a given value of the Lifshitz scaling parameter. We
propose that this class of models is dual to a class of models of
non-Fermi-liquid systems proposed by Castro-Neto et.al.Comment: 17 pages, 6 figures, pdfLatex; small corrections to figure 10 in this
versio
Black holes and black branes in Lifshitz spacetimes
We construct analytic solutions describing black holes and black branes in
asymptotically Lifshitz spacetimes with arbitrary dynamical exponent z and for
arbitrary number of dimensions. The model considered consists of Einstein
gravity with negative cosmological constant, a scalar, and N U(1) gauge fields
with dilatonic-like couplings. We study the phase diagrams and thermodynamic
instabilities of the solution, and find qualitative differences between the
cases with 12.Comment: 27 pages, 10 figures; v2 references added, minor comments adde
Lovelock-Lifshitz Black Holes
In this paper, we investigate the existence of Lifshitz solutions in Lovelock
gravity, both in vacuum and in the presence of a massive vector field. We show
that the Lovelock terms can support the Lifshitz solution provided the
constants of the theory are suitably chosen. We obtain an exact black hole
solution with Lifshitz asymptotics of any scaling parameter in both
Gauss-Bonnet and in pure 3rd order Lovelock gravity. If matter is added in the
form of a massive vector field, we also show that Lifshitz solutions in
Lovelock gravity exist; these can be regarded as corrections to Einstein
gravity coupled to this form of matter. For this form of matter we numerically
obtain a broad range of charged black hole solutions with Lifshitz asymptotics,
for either sign of the cosmological constant. We find that these asymptotic
Lifshitz solutions are more sensitive to corrections induced by Lovelock
gravity than are their asymptotic AdS counterparts. We also consider the
thermodynamics of the black hole solutions and show that the temperature of
large black holes with curved horizons is proportional to where is
the critical exponent; this relationship holds for black branes of any size. As
is the case for asymptotic AdS black holes, we find that an extreme black hole
exists only for the case of horizons with negative curvature. We also find that
these Lovelock-Lifshitz black holes have no unstable phase, in contrast to the
Lovelock-AdS case. We also present a class of rotating Lovelock-Lifshitz black
holes with Ricci-flat horizons.Comment: 26 pages, 10 figures, a few references added, typo fixed and some
comments have been adde
Promoter hypermethylation and histone hypoacetylation contribute to pancreatic-duodenal homeobox 1 silencing in gastric cancer
Background and Aims: The expression of pancreatic-duodenal homeobox 1 (PDX1) in gastric cancer is aberrantly reduced. The aim of this study was to elucidate the regulation of DNA methylation and histone acetylation at the promoter for PDX1 silencing in gastric cancer. Methods: PDX1 expression in response to demethylation and acetylation was detected in human gastric cancer cell lines by reverse transcription-polymerase chain reaction (PCR) and western blot. Four CpG islands within the 5#-flanking region of PDX1 gene were analyzed with their transcription activities being detected by dual luciferase assay. Promoter hypermethylation was identified in gastric cancer cell lines and cancer tissues by methylation-specific PCR or bisulfite DNA sequencing PCR analysis. Histone acetylation was determined by chromatin immunoprecipitation (ChIP) assay. Results: Demethylation by 5′-aza-2′-deoxycytidine (5′-aza-dC) and/or acetylation by trichostatin A (TSA) restored PDX1 expression in gastric cancer cells. Hypermethylation was found in four CpG islands in six of seven cancer cell lines. However, only the distal CpG island located in the promoter fragment of PDX1, F383 (c.22063 to 21681 nt upstream of the ATG start codon) displayed significant transcriptional activity that could be suppressed by SssI methylase and increased by 5′-aza-dC and TSA. More than 70% of the single CpG sites in F383 were methylated with hypermethylation of F383 fragment more common in gastric cancerous tissues compared with the paired normal tissues (P < 0.05). ChIP assay showed F383 was also associated with low hypoacetylation level of the histones. Conclusion: Promoter hypermethylation and histone hypoacetylation contribute to PDX1 silencing in gastric cancer. © The Author 2010. Published by Oxford University Press. All rights reserved.postprin
Lifshitz black holes in string theory
We provide the first black hole solutions with Lifshitz asymptotics found in
string theory. These are expected to be dual to models enjoying anisotropic
scale invariance with dynamical exponent z=2 at finite temperature. We employ a
consistent truncation of type IIB supergravity to four dimensions with an
arbitrary 5-dimensional Einstein manifold times a circle as internal geometry.
New interesting features are found that significantly differ from previous
results in phenomenological models. In particular, small black holes are shown
to be thermodynamically unstable, analogously to the usual AdS-Schwarzschild
black holes, and extremality is never reached. This signals a possible
Hawking-Page like phase transition at low temperatures.Comment: 19 pages, 7 figures. v2 references adde
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