179 research outputs found
CernVM Online and Cloud Gateway: a uniform interface for CernVM contextualization and deployment
In a virtualized environment, contextualization is the process of configuring
a VM instance for the needs of various deployment use cases. Contextualization
in CernVM can be done by passing a handwritten context to the user data field
of cloud APIs, when running CernVM on the cloud, or by using CernVM web
interface when running the VM locally. CernVM Online is a publicly accessible
web interface that unifies these two procedures. A user is able to define,
store and share CernVM contexts using CernVM Online and then apply them either
in a cloud by using CernVM Cloud Gateway or on a local VM with the single-step
pairing mechanism. CernVM Cloud Gateway is a distributed system that provides a
single interface to use multiple and different clouds (by location or type,
private or public). Cloud gateway has been so far integrated with OpenNebula,
CloudStack and EC2 tools interfaces. A user, with access to a number of clouds,
can run CernVM cloud agents that will communicate with these clouds using their
interfaces, and then use one single interface to deploy and scale CernVM
clusters. CernVM clusters are defined in CernVM Online and consist of a set of
CernVM instances that are contextualized and can communicate with each other.Comment: Conference paper at the 2013 Computing in High Energy Physics (CHEP)
Conference, Amsterda
Applications of the Kuznetsov formula on GL(3) II: the level aspect
We develop an explicit Kuznetsov formula on GL(3) for congruence subgroups. Applications include a Lindelöf on average type bound for the sixth moment of GL(3) L-functions in the level aspect, an automorphic large sieve inequality, density results for exceptional eigenvalues and density results for Maaß forms violating the Ramanujan conjecture at finite places. © 2017, Springer-Verlag GmbH Deutschland
Uniform Titchmarsh divisor problems
Asymptotic formulae for Titchmarsh-type divisor sums are obtained with strong error terms that are uniform in the shift parameter. This applies to more general arithmetic functions such as sums of two squares, improving the error term in the representation of the number as a sum of a prime and two squares, and to Fourier coefficients of cusp forms, generalizing a result of Pitt
Micro-CernVM: Slashing the Cost of Building and Deploying Virtual Machines
The traditional virtual machine building and and deployment process is
centered around the virtual machine hard disk image. The packages comprising
the VM operating system are carefully selected, hard disk images are built for
a variety of different hypervisors, and images have to be distributed and
decompressed in order to instantiate a virtual machine. Within the HEP
community, the CernVM File System has been established in order to decouple the
distribution from the experiment software from the building and distribution of
the VM hard disk images.
We show how to get rid of such pre-built hard disk images altogether. Due to
the high requirements on POSIX compliance imposed by HEP application software,
CernVM-FS can also be used to host and boot a Linux operating system. This
allows the use of a tiny bootable CD image that comprises only a Linux kernel
while the rest of the operating system is provided on demand by CernVM-FS. This
approach speeds up the initial instantiation time and reduces virtual machine
image sizes by an order of magnitude. Furthermore, security updates can be
distributed instantaneously through CernVM-FS. By leveraging the fact that
CernVM-FS is a versioning file system, a historic analysis environment can be
easily re-spawned by selecting the corresponding CernVM-FS file system
snapshot.Comment: Conference paper at the 2013 Computing in High Energy Physics (CHEP)
Conference, Amsterda
Three-dimensional imaging of direct-written photonic structures
Third harmonic generation microscopy has been used to analyze the morphology
of photonic structures created using the femtosecond laser direct-write
technique. Three dimensional waveguide arrays and waveguide-Bragg gratings
written in fused-silica and doped phosphate glass were investigated. A
sensorless adaptive optical system was used to correct the optical aberrations
occurring in the sample and microscope system, which had a lateral resolution
of less than 500 nm. This non-destructive testing method creates volume
reconstructions of photonic devices and reveals details invisible to other
linear microscopy and index profilometry techniques.Comment: 8 pages, 3 color figures, 2 hyper-linked animation
The subconvexity problem for \GL_{2}
Generalizing and unifying prior results, we solve the subconvexity problem
for the -functions of \GL_{1} and \GL_{2} automorphic representations
over a fixed number field, uniformly in all aspects. A novel feature of the
present method is the softness of our arguments; this is largely due to a
consistent use of canonically normalized period relations, such as those
supplied by the work of Waldspurger and Ichino--Ikeda.Comment: Almost final version to appear in Publ. Math IHES. References
updated
Averages of Fourier coefficients of Siegel modular forms and representation of binary quadratic forms by quadratic forms in four variables
Let be a a negative discriminant and let vary over a set of
representatives of the integral equivalence classes of integral binary
quadratic forms of discriminant . We prove an asymptotic formula for for the average over of the number of representations of by an
integral positive definite quaternary quadratic form and obtain results on
averages of Fourier coefficients of linear combinations of Siegel theta series.
We also find an asymptotic bound from below on the number of binary forms of
fixed discriminant which are represented by a given quaternary form. In
particular, we can show that for growing a positive proportion of the
binary quadratic forms of discriminant is represented by the given
quaternary quadratic form.Comment: v5: Some typos correcte
Bounding sup-norms of cusp forms of large level
Let f be an -normalized weight zero Hecke-Maass cusp form of square-free
level N, character and Laplacian eigenvalue . It is
shown that , from which the hybrid
bound (for some
) is derived. The first bound holds also for where F
is a holomorphic cusp form of weight k with the implied constant now depending
on k.Comment: version 3: substantially revised versio
- …