3 research outputs found
Optimal Control of Boolean Control Networks with Discounted Cost: An Efficient Approach based on Deterministic Markov Decision Process
This paper deals with the infinite-horizon optimal control problem for
Boolean control networks (BCNs) with a discounted-cost criterion. This problem
has been investigated in existing studies with algorithms characterized by high
computational complexity. We thus attempt to develop more efficient approaches
for this problem from a deterministic Markov decision process (DMDP)
perspective. First, we show the eligibility of a DMDP to model the control
process of a BCN and the existence of an optimal solution. Next, two approaches
are developed to handle the optimal control problem in a DMDP. One approach
adopts the well-known value iteration algorithm, and the other resorts to the
Madani's algorithm specifically designed for DMDPs. The latter approach can
find an exact optimal solution and outperform existing methods in terms of time
efficiency, while the former value iteration based approach usually obtains a
near-optimal solution much faster than all others. The 9-state-4-input
\textit{ara} operon network of the bacteria \textit{E. coli} is used to verify
the effectiveness and performance of our approaches. Results show that both
approaches can reduce the running time dramatically by several orders of
magnitude compared with existing work
An improved transformation between Fibonacci FSRs and Galois FSRs
Feedback shift registers (FSRs), which have two configurations: Fibonacci and
Galois, are a primitive building block in stream ciphers. In this paper, an
improved transformation is proposed between Fibonacci FSRs and Galois FSRs. In
the previous results, the number of stages is identical when constructing the
equivalent FSRs. In this paper, there is no requirement to keep the number of
stages equal for two equivalent FSRs here. More precisely, it is verified that
an equivalent Galois FSR with fewer stages cannot be found for a Fibonacci FSR,
but the converse is not true. Furthermore, the total number of equivalent
Galois FSRs for a given Fibonacci FSR with n stages is calculated. In order to
reduce the propagation time and memory, an effective algorithm is developed to
find equivalent Galois FSR and is proved to own minimal operators and stages.
Finally, the feasibility of our proposed strategies, to mutually transform
Fibonacci FSRs and Galois FSRs, is demonstrated by numerical examples.Comment: 8 pages, 2 figure
Distributed Pinning Control Design for Probabilistic Boolean Networks
This paper investigates the stabilization of probabilistic Boolean networks
(PBNs) via a novel pinning control strategy based on network structure. In a
PBN, each node needs to choose a Boolean function from candidate Boolean
function set at each time instance with certain probability. Owing to the
stochasticity, the uniform state feedback controllers, which is independent of
switching signal, might be out of work. Thereby, a criterion is derived to
determine that under what condition uniform controllers can be applied,
otherwise non-uniform controllers need to be utilized. Accordingly, an
algorithm is designed to find a series of state feedback pinning controllers,
under which such a PBN is stabilized to a prespecified steady state. It is
worth pointing out that the pinning control used in this paper only requires
local in-neighbors' information, rather than global information. Hence, it is
also termed as distributed pinning control and reduces the computational
complexity to a large extent. Profiting from this, it provides a potential to
deal with some large-scale networks. Finally, the mammalian cell-cycle
encountering a mutated phenotype is described as a PBN, and presented to
demonstrate the obtained results