160,856 research outputs found
Implications of ERM2 for Poland’s Monetary Policy
This study proposes an extension to the inflation targeting framework for Poland that takes into consideration the exchange rate stability constraints imposed by the obligatory participation in the ERM2 on the path to the euro. The modified policy framework is based on targeting the differential between the domestic and the implicit euro area inflation forecasts. The exchange rate stability objective enters the central bank reaction function and is treated as an indicator variable. Adjustments of interest rates respond to changes in the relative inflation forecast, while foreign exchange market intervention is applied for the purpose of stabilizing the exchange rate. The dynamic market equilibrium exchange rate is ascertained by employing the Johanssen cointegration tests and the threshold generalized autoregressive heteroscedasticity model with the in-mean extension and generalized error distribution (TGARCH-M-GED).http://deepblue.lib.umich.edu/bitstream/2027.42/40188/3/wp802.pd
First passage problems for upwards skip-free random walks via the paradigm
We develop the theory of the and scale functions for right-continuous
(upwards skip-free) discrete-time discrete-space random walks, along the lines
of the analogue theory for spectrally negative L\'evy processes. Notably, we
introduce for the first time in this context the one and two-parameter scale
functions , which appear for example in the joint problem of deficit at ruin
and time of ruin, and in problems concerning the walk reflected at an upper
barrier. Comparisons are made between the various theories of scale functions
as one makes time and/or space continuous. The theory is shown to be fruitful
by providing a convenient unified framework for studying dividends-capital
injection problems under various objectives, for the so-called compound
binomial risk model of actuarial science.Comment: 27 page
Optimization of Energy Harvesting MISO Communication System with Feedback
Optimization of a point-to-point (p2p) multipleinput single-output (MISO)
communication system is considered when both the transmitter (TX) and the
receiver (RX) have energy harvesting (EH) capabilities. The RX is interested in
feeding back the channel state information (CSI) to the TX to help improve the
transmission rate. The objective is to maximize the throughput by a deadline,
subject to the EH constraints at the TX and the RX. The throughput metric
considered is an upper bound on the ergodic rate of the MISO channel with
beamforming and limited feedback. Feedback bit allocation and transmission
policies that maximize the upper bound on the ergodic rate are obtained. Tools
from majorization theory are used to simplify the formulated optimization
problems. Optimal policies obtained for the modified problem outperform the
naive scheme in which no intelligent management of energy is performed.Comment: 11 page
Outsmarting Network Security with SDN Teleportation
Software-defined networking is considered a promising new paradigm, enabling
more reliable and formally verifiable communication networks. However, this
paper shows that the separation of the control plane from the data plane, which
lies at the heart of Software-Defined Networks (SDNs), introduces a new
vulnerability which we call \emph{teleportation}. An attacker (e.g., a
malicious switch in the data plane or a host connected to the network) can use
teleportation to transmit information via the control plane and bypass critical
network functions in the data plane (e.g., a firewall), and to violate security
policies as well as logical and even physical separations. This paper
characterizes the design space for teleportation attacks theoretically, and
then identifies four different teleportation techniques. We demonstrate and
discuss how these techniques can be exploited for different attacks (e.g.,
exfiltrating confidential data at high rates), and also initiate the discussion
of possible countermeasures. Generally, and given today's trend toward more
intent-based networking, we believe that our findings are relevant beyond the
use cases considered in this paper.Comment: Accepted in EuroSP'1
Pilot Beam Sequence Design for Channel Estimation in Millimeter-Wave MIMO Systems: A POMDP Framework
In this paper, adaptive pilot beam sequence design for channel estimation in
large millimeter-wave (mmWave) MIMO systems is considered. By exploiting the
sparsity of mmWave MIMO channels with the virtual channel representation and
imposing a Markovian random walk assumption on the physical movement of the
line-of-sight (LOS) and reflection clusters, it is shown that the sparse
channel estimation problem in large mmWave MIMO systems reduces to a sequential
detection problem that finds the locations and values of the non-zero-valued
bins in a two-dimensional rectangular grid, and the optimal adaptive pilot
design problem can be cast into the framework of a partially observable Markov
decision process (POMDP). Under the POMDP framework, an optimal adaptive pilot
beam sequence design method is obtained to maximize the accumulated
transmission data rate for a given period of time. Numerical results are
provided to validate our pilot signal design method and they show that the
proposed method yields good performance.Comment: 6 pages, 6 figures, submitted to IEEE ICC 201
A survey on OFDM-based elastic core optical networking
Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed
- …