5,011 research outputs found
Studies of Neutrino-Electron Scattering at the Kuo-Sheng Reactor Neutrino Laboratory
Studies on electron antineutrino-electron elastic scattering were performed
using a 200-kg CsI(Tl) scintillating crystal detector array at the Kuo-Sheng
Nuclear Power Plant in Taiwan. The measured cross section of R(exp) = [1.00 +-
0.32(stat)]xR(SM) is consistent with the Standard Model expectation and the
corresponding weak mixing angle derived is sin2T = 0.24 +- 0.05 (stat). The
results are consistent with a destructive interference effect between neutral
and charged-currents in this process. Limits on neutrino magnetic moment of
mu(nu_(e)) < 2.0 x 10^(-10) mu_(B) at 90% confidence level and on electron
antineutrino charge radius of r^(2) < (0.12 +- 2.07)x10^(-32) cm^2 were also
derived.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 4 pages,
LaTex, 4 eps figure
Smart Meter Privacy with an Energy Harvesting Device and Instantaneous Power Constraints
A smart meter (SM) periodically measures end-user electricity consumption and
reports it to a utility provider (UP). Despite the advantages of SMs, their use
leads to serious concerns about consumer privacy. In this paper, SM privacy is
studied by considering the presence of an energy harvesting device (EHD) as a
means of masking the user's input load. The user can satisfy part or all of
his/her energy needs from the EHD, and hence, less information can be leaked to
the UP via the SM. The EHD is typically equipped with a rechargeable energy
storage device, i.e., a battery, whose instantaneous energy content limits the
user's capability in covering his/her energy usage. Privacy is measured by the
information leaked about the user's real energy consumption when the UP
observes the energy requested from the grid, which the SM reads and reports to
the UP. The minimum information leakage rate is characterized as a computable
information theoretic single-letter expression when the EHD battery capacity is
either infinite or zero. Numerical results are presented for a discrete binary
input load to illustrate the potential privacy gains from the existence of a
storage device.Comment: To be published in IEEE ICC201
Distortion Exponent in MIMO Channels with Feedback
The transmission of a Gaussian source over a block-fading multiple antenna
channel in the presence of a feedback link is considered. The feedback link is
assumed to be an error and delay free link of capacity 1 bit per channel use.
Under the short-term power constraint, the optimal exponential behavior of the
end-to-end average distortion is characterized for all source-channel bandwidth
ratios. It is shown that the optimal transmission strategy is successive
refinement source coding followed by progressive transmission over the channel,
in which the channel block is allocated dynamically among the layers based on
the channel state using the feedback link as an instantaneous automatic repeat
request (ARQ) signal.Comment: Presented at the IEEE Information Theory Workshop (ITW), Taormina,
Italy, Oct. 200
Diversity-Multiplexing Tradeoffs in MIMO Relay Channels
A multi-hop relay channel with multiple antenna terminals in a quasi-static
slow fading environment is considered. For both full-duplex and half-duplex
relays the fundamental diversity-multiplexing tradeoff (DMT) is analyzed. It is
shown that, while decode-and-forward (DF) relaying achieves the optimal DMT in
the full-duplex relay scenario, the dynamic decode-and-forward (DDF) protocol
is needed to achieve the optimal DMT if the relay is constrained to half-duplex
operation. For the latter case, static protocols are considered as well, and
the corresponding achievable DMT performance is characterized.Comment: To appear at IEEE Global Communications Conf. (Globecom), New
Orleans, LA, Nov. 200
Information-Theoretic Methods for Identifying Relationships among Climate Variables
Information-theoretic quantities, such as entropy, are used to quantify the
amount of information a given variable provides. Entropies can be used together
to compute the mutual information, which quantifies the amount of information
two variables share. However, accurately estimating these quantities from data
is extremely challenging. We have developed a set of computational techniques
that allow one to accurately compute marginal and joint entropies. These
algorithms are probabilistic in nature and thus provide information on the
uncertainty in our estimates, which enable us to establish statistical
significance of our findings. We demonstrate these methods by identifying
relations between cloud data from the International Satellite Cloud Climatology
Project (ISCCP) and data from other sources, such as equatorial pacific sea
surface temperatures (SST).Comment: Presented at the Earth-Sun System Technology Conference (ESTC 2008),
Adelphi, MD. http://esto.nasa.gov/conferences/estc2008/ 3 pages, 3 figures.
Appears in the Proceedings of the Earth-Sun System Technology Conference
(ESTC 2008), Adelphi, M
Türkiye'de ülke içinde yerinden edilme sorunu: tespitler ve çözüm önerileri = The problem of internal displacement in Turkey: assessment and policy proposals
Bu rapor, Doç. Dr. A. Tamer Aker (psikiyatr, Kocaeli Üniversitesi), Yrd. Doç. Dr. A. Betül Çelik (siyaset bilimci, Sabancı Üniversitesi), Dilek Kurban (hukuk doktoru, TESEV), Doç. Dr. Turgay Ünalan (nüfusbilimci, Hacettepe Üniversitesi) ve Yrd. Doç. Dr. H. Deniz Yükseker'den (sosyolog, Koç Üniversitesi) oluşan TESEV Ülke İçinde Yerinden Edilme Araştırma ve İzleme Grubu tarafından hazırlanmıştır. Grup, yerinden edilmeyi çatışma ortamının keskinleştirdiği devlet merkezli düşünüşün ve çeşitli ideolojik kamplaşmaların ötesinde, yurttaşlık haklarının yeniden tesisi ve toplumsal rehabilitasyon eksenlerinde ve insani boyutları bağlamında ele almaktadır
The Multi-way Relay Channel
The multiuser communication channel, in which multiple users exchange
information with the help of a relay terminal, termed the multi-way relay
channel (mRC), is introduced. In this model, multiple interfering clusters of
users communicate simultaneously, where the users within the same cluster wish
to exchange messages among themselves. It is assumed that the users cannot
receive each other's signals directly, and hence the relay terminal in this
model is the enabler of communication. In particular, restricted encoders,
which ignore the received channel output and use only the corresponding
messages for generating the channel input, are considered. Achievable rate
regions and an outer bound are characterized for the Gaussian mRC, and their
comparison is presented in terms of exchange rates in a symmetric Gaussian
network scenario. It is shown that the compress-and-forward (CF) protocol
achieves exchange rates within a constant bit offset of the exchange capacity
independent of the power constraints of the terminals in the network. A finite
bit gap between the exchange rates achieved by the CF and the
amplify-and-forward (AF) protocols is also shown. The two special cases of the
mRC, the full data exchange model, in which every user wants to receive
messages of all other users, and the pairwise data exchange model which
consists of multiple two-way relay channels, are investigated in detail. In
particular for the pairwise data exchange model, in addition to the proposed
random coding based achievable schemes, a nested lattice coding based scheme is
also presented and is shown to achieve exchange rates within a constant bit gap
of the exchange capacity.Comment: Revised version of our submission to the Transactions on Information
Theor
Joint Source-Channel Cooperative Transmission over Relay-Broadcast Networks
Reliable transmission of a discrete memoryless source over a multiple-relay
relay-broadcast network is considered. Motivated by sensor network
applications, it is assumed that the relays and the destinations all have
access to side information correlated with the underlying source signal. Joint
source-channel cooperative transmission is studied in which the relays help the
transmission of the source signal to the destinations by using both their
overheard signals, as in the classical channel cooperation scenario, as well as
the available correlated side information. Decode-and-forward (DF) based
cooperative transmission is considered in a network of multiple relay terminals
and two different achievability schemes are proposed: i) a regular encoding and
sliding-window decoding scheme without explicit source binning at the encoder,
and ii) a semi-regular encoding and backward decoding scheme with binning based
on the side information statistics. It is shown that both of these schemes lead
to the same source-channel code rate, which is shown to be the "source-channel
capacity" in the case of i) a physically degraded relay network in which the
side information signals are also degraded in the same order as the channel;
and ii) a relay-broadcast network in which all the terminals want to
reconstruct the source reliably, while at most one of them can act as a relay.Comment: Submitted to IEEE Transactions on Information Theory, 201
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