2 research outputs found
Community Detection in Signed Networks: an Error-Correcting Code Approach
In this paper, we consider the community detection problem in signed
networks, where there are two types of edges: positive edges (friends) and
negative edges (enemies). One renowned theorem of signed networks, known as
Harary's theorem, states that structurally balanced signed networks are
clusterable. By viewing each cycle in a signed network as a parity-check
constraint, we show that the community detection problem in a signed network
with two communities is equivalent to the decoding problem for a parity-check
code. We also show how one can use two renowned decoding algorithms in error-
correcting codes for community detection in signed networks: the bit-flipping
algorithm, and the belief propagation algorithm. In addition to these two
algorithms, we also propose a new community detection algorithm, called the
Hamming distance algorithm, that performs community detection by finding a
codeword that minimizes the Hamming distance. We compare the performance of
these three algorithms by conducting various experiments with known ground
truth. Our experimental results show that our Hamming distance algorithm
outperforms the other two
Symbolic Stochastic Chase Decoding of Reed-Solomon and BCH Codes
This paper proposes the Symbolic-Stochastic Chase Decoding Algorithm (S-SCA)
for the Reed-Solomon (RS) and BCH codes. By efficient usage of void space
between constellation points for -ary modulations and using soft information
at the input of the decoder, the S-SCA is capable of outperforming conventional
Symbolic-Chase algorithm (S-CA) with less computational cost. Since the S-SCA
starts with the randomized generation of likely test-vectors, it reduces the
complexity to polynomial order and also it does not need to find the least
reliable symbols to generate test-vectors. Our simulation results show that by
increasing the number of test-vectors, the performance of the algorithm can
approach the ML bound. The S-SCA() provides near dB gain in comparison
with S-CA() for RS code using -QAM. Furthermore, the
algorithm provides near dB further gain with iteration compared with
S-CA() when RS code is used in an AWGN channel. For the
Rayleigh fading channel and the same code, the algorithm provides more that
dB gain. Also for BCH codes and -PSK modulation the proposed
algorithm provides dB gain with less complexity.
This decoder is Soft-Input Soft-Output (SISO) decoder and is highly
attractive in low power applications. Finally, the Symbolic-Search
Bitwise-Transmission Stochastic Chase Algorithm (SSBT-SCA) was introduced for
RS codes over BPSK transmission that is capable of generating symbolic
test-vectors that reduce complexity and mitigate burst errors