Publications

A CM2-S3 transmission link in wireless body area networks (WBAN) is implemented with a joint source channel coding (JSCC) system based on double protograph low-density parity-check (DP-LDPC) code pairs with high reliability and low power consumption. For the practicality and suitability considerations, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -ary differential chaos shift keying scheme is introduced to modulate the CM2-S3 channel with better performance than the standard modulations in WBAN. Due to the non-Gaussian-like distribution of the CM2-S3 channel model, the initial joint protograph extrinsic information transfer (JPEXIT) algorithm does not work as a coding analysis tool. To solve this problem, a numerical Gaussian approximation is employed to modify the iterative mutual information function of the JPEXIT for achieving more precise output. Then, a joint code rate compatible (JCRC) method, designed with compatibility in resisting variable channel variances and adapting different source statistics, is proposed for optimizing the DP-LDPC code pairs. Based on the JCRC method, the code searching algorithm is simplified with lower complexity because of the reduced cycle-index. The simulation results show that optimized code pairs have better bit-error ratio performances compared to existing codes, which provides a strong technical support to promote high-quality data transmission in eHealthcare on the physical layer.

This paper studies the passive network synthesis problem of biquadratic impedances as five-element bridge networks. By investigating the realizability conditions of the configurations that can cover all the possible cases, a necessary and sufficient condition is obtained for biquadratic impedances to be realizable as two-reactive five-element bridge networks. Based on the types of the two reactive elements, the discussion is divided into two parts, and a canonical form for biquadratic impedances is utilized to simplify and combine the conditions. Moreover, the realizability result for the biquadratic impedance is extended to the general five-element bridge networks. Some numerical examples are presented for illustration.

This paper is concerned with the derivative feedback control of a 2-degree-of-freedom (2-DOF) torsional bar with parameter perturbations. The time-delay is introduced into the controller and the maximum allowed time-delay bound is estimated by employing a discretized Lyapunov functional method. It is shown, through a numerical example with simulation results, that suitably introducing time-delay into the controller can indeed improve the performance of the stability of the closed-loop system.

No abstract is provided for this article.

p53 regulates the cellular response to genotoxic damage and prevents carcinogenic events. Theoretical and experimental studies state that the p53-Mdm2 network constitutes the core module of regulatory interactions activated by cellular stress among a great variety of signaling pathways. In this paper, a strategy to control the p53-Mdm2 network regulated by p14ARF is developed, based on the pinning control technique, which consists into applying local feedback controllers to a small number of nodes (pinned ones) in the network. Pinned nodes are selected on the basis of their importance level in a topological hierarchy, degree of connectivity in the network, and the biological role they perform. In this paper, two cases are considered. For the first case, oscillatory pattern under gamma-radiation is recovered; afterward, as the second case, increased expression of p53 level is taken into account. For both cases, the control law is applied to p14ARF(pinned node), and overexpressed Mdm2-mediated p53 degradation condition is considered as initial behavior. The approach in this paper uses a computational algorithm, which opens an alternative path to understanding cellular responses to stress, doing it possible to model and control the gene regulatory network dynamics in two different biological contexts. As the main result of the proposed control technique, the two mentioned desired behaviors are obtained.

A generalized-eigenvector-based condition is derived for the target controllability, which is necessary and sufficient. It is then applied to networked MIMO LTI systems with some lower-dimensional conditions established. These conditions are easily-verified, which explicitly show how the node-system dynamics, network topology, inner couplings, target-node positions, and external control inputs affect the target controllability of the network. Then, the target controllability of multi-agent systems is revisited. The omission of the criterion given in (Guan and Wang, 2019) is revealed. As a remedy, a modified criterion is suggested. Several examples show the effectiveness of the conditions.

A stream cipher based on a spatiotemporal chaotic system is proposed. A one-way coupled map lattice consisting of logistic maps is served as the spatiotemporal chaotic system. Multiple keystreams are generated from the coupled map lattice by using simple algebraic computations, and then are used to encrypt plaintext via bitwise XOR. These make the cipher rather simple and efficient. Numerical investigation shows that the cryptographic properties of the generated keystream are satisfactory. The cipher seems to have higher security, higher efficiency and lower computation expense than the stream cipher based on a spatiotemporal chaotic system proposed recently.

Journal Article Lower-order state-space self-tuning control for a stochastic chaotic hybrid system Get access Tseng-Hsu Chien, Tseng-Hsu Chien **Email: shtsai@mail.ncku.edu.tw Search for other works by this author on: Oxford Academic Google Scholar Jason Sheng Hong Tsai, Jason Sheng Hong Tsai Search for other works by this author on: Oxford Academic Google Scholar Shu-Mei Guo, Shu-Mei Guo Search for other works by this author on: Oxford Academic Google Scholar Guanrong Chen Guanrong Chen Search for other works by this author on: Oxford Academic Google Scholar IMA Journal of Mathematical Control and Information, Volume 24, Issue 2, June 2007, Pages 219–234, https://doi.org/10.1093/imamci/dnl024 Published: 01 June 2007

Superdiffusion is an interesting phenomenon from both theoretical and practical perspectives. In this article, we propose a sufficient condition for the occurrence of superdiffusion on duplex networks by applying the generating functionology from combinatorial mathematics. Our result indicates that, with fixed values of intralayer diffusion constants, superdiffusion emerges from a certain combination of different network topologies, which provides a topological mechanism to regulate the whole diffusion process. On a more general ground, we provide two interlayer linking strategies to expand the applicability of the aforementioned topological mechanism on real-world networks, and construct a class of specific duplex networks on which superdiffusion occurs. We further verify that diffusion with negative interlayer correlation is faster than that with positive correlation from a typical duplex structure. Given the ubiquity of diffusion in the real world, our results constitute a significant step toward a better understanding of superdiffusion processes on multiplex networks.

Swarms evolving from collective behaviors among multiple individuals are commonly seen in nature, which enables biological systems to exhibit more efficient and robust collaboration. Creating similar swarm intelligence in engineered robots poses challenges to the design of collaborative algorithms that can be programmed at large scales. The assignment-based method has played an eminent role for a very long time in solving collaboration problems of robot swarms. However, it faces fundamental limitations in terms of efficiency and robustness due to its unscalability to swarm variants. This article presents a tutorial review on recent advances in assignment-free collaboration of robot swarms, focusing on the problem of shape formation. A key theoretical component is the recently developed \emph{mean-shift exploration} strategy, which improves the collaboration efficiency of large-scale swarms by dozens of times. Further, the efficiency improvement is more significant as the swarm scale increases. Finally, this article discusses three important applications of the mean-shift exploration strategy, including precise shape formation, area coverage formation, and maneuvering formation, as well as their corresponding industrial scenarios in smart warehousing, area exploration, and cargo transportation.