603 research outputs found
BIOMONITORING OF ECOLOGICAL STATE OF THE ENVIRONMENT IN THE ZONE OF INFLUENCE OF THE “CHERVONOGRADSKA” MINE OF THE LVIV-VOLYN COALFIELD
Coal mining has a very negative impact on the environment and it requires monitoring
studies to assess the degree of environmental pollution
Characterization of Coded Random Access with Compressive Sensing based Multi-User Detection
The emergence of Machine-to-Machine (M2M) communication requires new Medium
Access Control (MAC) schemes and physical (PHY) layer concepts to support a
massive number of access requests. The concept of coded random access,
introduced recently, greatly outperforms other random access methods and is
inherently capable to take advantage of the capture effect from the PHY layer.
Furthermore, at the PHY layer, compressive sensing based multi-user detection
(CS-MUD) is a novel technique that exploits sparsity in multi-user detection to
achieve a joint activity and data detection. In this paper, we combine coded
random access with CS-MUD on the PHY layer and show very promising results for
the resulting protocol.Comment: Submitted to Globecom 201
Distributed Adaptive Learning with Multiple Kernels in Diffusion Networks
We propose an adaptive scheme for distributed learning of nonlinear functions
by a network of nodes. The proposed algorithm consists of a local adaptation
stage utilizing multiple kernels with projections onto hyperslabs and a
diffusion stage to achieve consensus on the estimates over the whole network.
Multiple kernels are incorporated to enhance the approximation of functions
with several high and low frequency components common in practical scenarios.
We provide a thorough convergence analysis of the proposed scheme based on the
metric of the Cartesian product of multiple reproducing kernel Hilbert spaces.
To this end, we introduce a modified consensus matrix considering this specific
metric and prove its equivalence to the ordinary consensus matrix. Besides, the
use of hyperslabs enables a significant reduction of the computational demand
with only a minor loss in the performance. Numerical evaluations with synthetic
and real data are conducted showing the efficacy of the proposed algorithm
compared to the state of the art schemes.Comment: Double-column 15 pages, 10 figures, submitted to IEEE Trans. Signal
Processin
Nonreciprocal Bloch Oscillations in Magneto-Optic Waveguide Arrays
We show that nonreciprocal optical Bloch-like oscillations can emerge in
transversely magnetized waveguide arrays in the presence of an effective index
step between the waveguides. Normal modes of the system are shown to acquire
different wavenumbers in opposite propagation directions. Significant
differences in phase coherence and decoherence between these normal modes are
presented and discussed. Non-reciprocity is established by imposing unequal
vertical refractive index gradients at the substrate/core, and core/cover
interfaces in the presence of transverse magnetization.Comment: 12 pages, 2 figure
On the Importance of Exploration for Real Life Learned Algorithms
The quality of data driven learning algorithms scales significantly with the
quality of data available. One of the most straight-forward ways to generate
good data is to sample or explore the data source intelligently. Smart sampling
can reduce the cost of gaining samples, reduce computation cost in learning,
and enable the learning algorithm to adapt to unforeseen events. In this paper,
we teach three Deep Q-Networks (DQN) with different exploration strategies to
solve a problem of puncturing ongoing transmissions for URLLC messages. We
demonstrate the efficiency of two adaptive exploration candidates,
variance-based and Maximum Entropy-based exploration, compared to the standard,
simple epsilon-greedy exploration approach
Model-free Reinforcement Learning of Semantic Communication by Stochastic Policy Gradient
Following the recent success of Machine Learning tools in wireless
communications, the idea of semantic communication by Weaver from 1949 has
gained attention. It breaks with Shannon's classic design paradigm by aiming to
transmit the meaning, i.e., semantics, of a message instead of its exact
version, allowing for information rate savings. In this work, we apply the
Stochastic Policy Gradient (SPG) to design a semantic communication system by
reinforcement learning, separating transmitter and receiver, and not requiring
a known or differentiable channel model -- a crucial step towards deployment in
practice. Further, we derive the use of SPG for both classic and semantic
communication from the maximization of the mutual information between received
and target variables. Numerical results show that our approach achieves
comparable performance to a model-aware approach based on the reparametrization
trick, albeit with a decreased convergence rate.Comment: Accepted for publication in IEEE International Conference on Machine
Learning for Communication and Networking (ICMLCN 2024), Source Code:
https://github.com/ant-uni-bremen/SINFON
Downlink beamforming concepts in UTRA FDD
This article gives a comparison of beamforming concepts. Adaptive beamforming and fixed beam switching in WCDMA-FDD-mode are compared from a system level perspective, ordinary sectorization (three 120° sectors) serves as a basis for comparison. Pilot channels P-CPICH (Primary Common Pilot Channel) and S-CPICH (Secondary CPICH) are considered as additional interference. For adaptive beamforming channel estimation has to be based on the pilot bit sequence on DPCCH (Dedicated Physical Control Channel) which leads to degradation especially for high mobile velocities and large angular dispersions of the multipath channel
Стратегия установления выводимости формул в структурных функциональных моделях
Рассматривается исчисление рекурсивных предложений для теории структурных функциональных моделей. Исследуются вопросы разрешимости и полноты исчисления. Предлагаются стратегия и алгоритм установления выводимости формул исчисления, показывается корректность алгоритма и определяется оценка его эффективности
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