Distributed dynamic event-based finite-time dissipative synchronization control for semi-Markov switched fuzzy cyber-physical systems against random packet losses

This paper is concerned with the finite-time dissipative synchronization control problem of semi-Markov switched cyber-physical systems in the presence of packet losses, which is constructed by the Takagi–Sugeno fuzzy model. To save the network communication burden, a distributed dynamic event-triggered mechanism is developed to restrain the information update. Besides, random packet dropouts following the Bernoulli distribution are assumed to occur in sensor to controller channels, where the triggered control input is analyzed via an equivalent method containing a new stochastic variable. By establishing the mode-dependent Lyapunov–Krasovskii functional with augmented terms, the finite-time boundness of the error system limited to strict dissipativity is studied. As a result of the help of an extended reciprocally convex matrix inequality technique, less conservative criteria in terms of linear matrix inequalities are deduced to calculate the desired control gains. Finally, two examples in regard to practical systems are provided to display the effectiveness of the proposed theory.

Effects of physical exercise on the developmental expression of hippocampal zinc transporter 1 and glutamate receptor subunit 2, and on cognitive function in a rat model of recurrent neonatal seizure

BACKGROUND： Developmental seizures are pathologically characterized by regenerative sprouting of hippocampal mossy fibers rich in Zn^2＋. Zn^2＋ metabolism in the mossy fiber pathway, and Zn^2＋ accumulation in presynaptic membrane vesicles, are dependent on zinc transporter 1 （ZnT1） and glutamate receptor subunit 2 （GluR2）. OBJECTIVE： To investigate the effects of long-term recurrent neonatal seizure, in the presence and absence of physical exercise, on the developmental expression of hippocampal zinc transporter 1 （ZnT1） and GluR2, and on cognitive function in rats. DESIGN, TIME AND SETTING： Based on behavioral examination and molecular biological research, a randomized, controlled animal experiment was performed at the Department of Neurobiology, Medical College of Soochow University, between January 2007 and April 2008. MATERIALS： Twenty-one 6-day-old Sprague Dawley rats of either gender were employed in this study. ZnT1 mRNA in situ hybridization kit was provided by Tianjin Haoyang Biological Manufacture Co.,Ltd., China. Rabbit anti-GluR2 was purchased from Santa Cruz Biotech, Inc, USA. METHODS： Rats were randomly divided into a recurrent seizure group （n = 11） and a control group （n = 10）. In the recurrent seizure group, 30-minute seizure was induced by flurothyl gas inhalation for a total of 6 consecutive days. Rats from the control group underwent experimental procedures similar to the recurrent seizure group, with the exception of flurothyl gas inhalation. Thirty minutes of treadmill exercise was performed daily by all rats at postnatal days 51–56. MAIN OUTCOME MEASURES： At postnatal day 82, rat hippocampal tissue was harvested for analysis of hippocampal ZnT1 and GluR2 expression by in situ hybridization and immunohistochemistry, respectively. Rat learning and memory capabilities were examined using the Y-maze test. RESULTS： In the recurrent seizure group, the gray scale value of ZnT1 in situ hybridization positive neurons in the hippocampal CA3 region was significantly greater （P 〈 0.05）, while the gray scale value of GluR2 immunoreactive neurons in the hippocampal hilus and dentate gyrus was significantly lower （P 〈 0.05）, than in the control group. At postnatal days 29–35, numbers of trials to criteria for successful learning were greater in the recurrent seizure group than in the control group （P 〈 0.05）; at postnatal days 61–67, the numbers of trials to criteria for successful learning were similar between the two groups （P 〉 0.05）. At postnatal days 29–35 and 61–67, there was no significant difference in memory capability between the recurrent seizure and control groups （P 〉 0.05）. CONCLUSION： Physical exercise likely improves the learning deficits caused by recurrent neonatal seizure in rats during brain development by modulating ZnT1 and GluR2 expression.

Zinc transporter-3 expression and long-term cognitive impairments in a rat model of neonatal concurrent seizure

BACKGROUND： Developmental seizures, which are pathologically characterized by regenerative sprouting of hippocampal mossy fibers, cause long-term damaging effects to synaptic plasticity. Zn^2＋ metabolism has been shown to contribute to the regenerative sprouting of hippocampal mossy fibers Furthermore, zinc transporter-3 （ZnT3） is responsible for Zn^2＋ transport in the hippocampal mossy fiber pathway. OBJECTIVE： To investigate the effects of long-term recurrent neonatal seizures on learning, memory formation and hippocampal ZnT3 expression in rats. DESIGN, TIME AND SETTING： Based on molecular biological research and behavioral examination a randomized, controlled, animal experiment was performed at the Laboratory Animal Center, Peking University Health Science Center, between October 2004 and July 2005. MATERIALS： Flurothyl was purchased from Aldrich Chemical Co., USA. ZnT3 mRNA in situ hybridization kits were provided by Tianjin Haoyang Biological Manufacture Co., Ltd., China. Morris water maze was produced by Shanghai Jiliang Science and Technology Co., Ltd., China. METHODS： Sixty, 6-day old, Wistar rats were randomly divided into three groups： single seizure （n = 21）, recurrent seizure （n = 21, one seizure daily for 6 consecutive days）, and control （n = 18）. Seizures were induced by flurothyl gas inhalation, in the single seizure and recurrent seizure groups. MAIN OUTCOME MEASURES： At postnatal days 12, 46 and 90, rat hippocampal ZnT3 mRNA expression was detected by RT-PCR; at postnatal days 46 and 90, ZnT3 mRNA expression was determined by in situ hybridization; and at postnatal days 41-46 and 85 90, rat spatial learning and memory formation were examined by the Morris water maze test. RESULTS： RT-PCR results revealed that at postnatal day 12, ZnT3 expression was significantly greater in the recurrent seizure group than in the control and single seizure groups, and at day 46, it was also significantly greater in the recurrent seizure group compared with the control group （P 〈 0.05）. In situ hybridization results showed that at postnatal day 46, the recurrent seizure group exhibited increased hippocampal ZnT3 expression over the control and single seizure groups （P〈0.05）. Morris water maze test results displayed that, in the first place navigation test at postnatal day 44, and the second test at days 87-88, the recurrent seizure group exhibited significantly higher value of average escape latency compared with the control group （P 〈 0.05）. In the two spatial probe tests, the search strategies were significantly inferior in the recurrent seizure group than in the control and single seizure groups （P 〈 0.05）. CONCLUSION： Neonatal concurrent seizures produce long-term damaging effects on hippocampal ZnT3 expression and cognitive function, while both of which have no parallel correlation.

Robust fuzzy control of Takagi-Sugeno fuzzy neural networks with discontinuous activation functions and time delays

The problem of global robust asymptotical stability for a class of Takagi-Sugeno fuzzy neural networks（TSFNN） with discontinuous activation functions and time delays is investigated by using Lyapunov stability theory.Based on linear matrix inequalities（LMIs）,we originally propose robust fuzzy control to guarantee the global robust asymptotical stability of TSFNNs.Compared with the existing literature,this paper removes the assumptions on the neuron activations such as Lipschitz conditions,bounded,monotonic increasing property or the right-limit value is bigger than the left one at the discontinuous point.Thus,the results are more general and wider.Finally,two numerical examples are given to show the effectiveness of the proposed stability results.