72,584 research outputs found
Koszul differential graded algebras and BGG correspondence
The concept of Koszul differential graded algebra (Koszul DG algebra) is
introduced. Koszul DG algebras exist extensively, and have nice properties
similar to the classic Koszul algebras. A DG version of the Koszul duality is
proved. When the Koszul DG algebra is AS-regular, the Ext-algebra of
is Frobenius. In this case, similar to the classical BGG correspondence,
there is an equivalence between the stable category of finitely generated left
-modules, and the quotient triangulated category of the full triangulated
subcategory of the derived category of right DG -modules consisting of all
compact DG modules modulo the full triangulated subcategory consisting of all
the right DG modules with finite dimensional cohomology. The classical BGG
correspondence can derived from the DG version.Comment: 29 page
Massive Complex Scalar Field in a Kerr-Sen Black Hole Background: Exact Solution of Wave Equation and Hawking Radiation
The separated radial part of a massive complex scalar wave equation in the
Kerr-Sen geometry is shown to satisfy the generalized spheroidal wave equation
which is, in fact, a confluent Heun equation up to a multiplier. The Hawking
evaporation of scalar particles in the Kerr-Sen black hole background is
investigated by the Damour-Ruffini-Sannan's method. It is shown that quantum
thermal effect of the Kerr-Sen black hole has the same characteras that of the
Kerr-Newman black hole.Comment: Revtex, 5 pages, no figure, submitted to Phys. Rev.
Sending multiple RTP streams in a single RTP session
This memo expands and clarifies the behavior of Real-time Transport Protocol (RTP) endpoints that use multiple synchronization sources (SSRCs). This occurs, for example, when an endpoint sends multiple RTP streams in a single RTP session. This memo updates RFC 3550 with regard to handling multiple SSRCs per endpoint in RTP sessions, with a particular focus on RTP Control Protocol (RTCP) behavior. It also updates RFC 4585 to change and clarify the calculation of the timeout of SSRCs and the inclusion of feedback messages
Extending the Energy Framework for Network Simulator 3 (ns-3)
The problem of designing and simulating optimal transmission protocols for
energy harvesting wireless networks has recently received considerable
attention, thus requiring for an accurate modeling of the energy harvesting
process and a consequent redesign of the simulation framework to include it.
While the current ns-3 energy framework allows the definition of new energy
sources that incorporate the contribution of an energy harvester, the
integration of an energy harvester component into an existing energy source is
not straightforward using the existing energy framework. In this poster, we
propose an extension of the energy framework currently released with ns-3 in
order to explicitly introduce the concept of an energy harvester. Starting from
the definition of the general interface, we then provide the implementation of
two simple models for the energy harvester. In addition, we extend the set of
implementations of the current energy framework to include a model for a
supercapacitor energy source and a device energy model for the energy
consumption of a sensor. Finally, we introduce the concept of an energy
predictor, that gathers information from the energy source and harvester and
use this information to predict the amount of energy that will be available in
the future, and we provide an example implementation. As a result of these
efforts, we believe that our contributions to the ns-3 energy framework will
provide a useful tool to enhance the quality of simulations of energy-aware
wireless networks.Comment: 2 pages, 4 figures. Poster presented at WNS3 2014, Atlanta, G
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