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The problem of $ L_1 $ L 1 output tracking control of positive linear systems in finite time is addressed in this paper. By constructing a linear copositive Lyapunov–Krasovskii functional, some sufficient conditions are achieved to ensure that the states are finite-time bounded and the measurement outputs have $ L_1- $ L 1 − gain performance for given systems, respectively. Next, a state feedback controller is designed to ensure that the output signals of the tracking system can effectively trace the specified signals of reference model with finite-time boundedness and $ L_1 $ L 1 -gain performance. Finally, an example is given to illustrate the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

This paper is concerned with the design of positive L1$$ {L}_1 $$ filter for positive Markovian jump systems (PMJSs) with adaptive event‐triggered mechanism and quantization. Considering the mode jump of the system, a new adaptive event‐triggered condition is established, which not only can regulate the communication threshold according to the error of dynamic systems, but also can avoid the asynchronous phenomenon between the system mode and the filter mode. In order to further reduce the burden of communication, a new positive L1$$ {L}_1 $$ filter with the quantized measure system output is developed, and the design condition which ensures the filter error system to be stochastically stable with L1$$ {L}_1 $$ performance is presented which can be solved in terms of linear programming (LP) technique. It is illustrated that there is no Zeno phenomenon. The proposed results are applied to the power allocation in a mobile telecommunication system, and it is shown that compared with the existing results, the event‐triggered filter of this paper has some advantages. [ABSTRACT FROM AUTHOR]

This article investigates stochastic stability of positive singular Markovian jump systems (PSMJSs) with mode-dependent derivative-term coefficient. Different from the existing results, the condition on stochastic stability of PSMJSs associated with state jumps behavior at switching instants is given by means of linear co-positive Lyapunuov function. On the basis of it, the conditions on stochastic stability under the cases of partially known transition rates and uncertain transition rates have been presented, respectively. All obtained conditions can be solved by linear programming (LP) technique. Finally, an example is introduced to illustrate the effectiveness and the merits of the results proposed in this article. [ABSTRACT FROM AUTHOR]

This paper focuses on positive linear time-invariant systems with constant coefficients and specific exogenous disturbance. The problem of finding a hyper-pyramid to bound the set of the states that are reachable from the origin in the Euclidean space is addressed, subject to inputs whose ( 1 , 1 ) -norm or ( ∞ , 1 ) -norm is bounded by a prescribed constant. The Lyapunov approach is applied and a bounding hyper-pyramid is obtained by solving a set of inequalities. Iterative procedures (with an adjustable parameter) for reducing the hyper-volume of the bounding hyper-pyramid for the reachable set are proposed. [ABSTRACT FROM AUTHOR]

This paper is concerned with the absolute and robust stability for a class of neutral-type Lur'e systems with an interval time-varying delay and sector-bounded nonlinearity. By discretising the delay interval into two segmentations with an unequal width, new delay-dependent sufficient conditions for the absolute and robust stability of neutral-type Lur'e systems are proposed in terms of linear matrix inequalities (LMIs) by employing a modified Lyapunov-Krasovskii functional (LKF). These conditions reduce the conservativeness in computing the maximum allowed delay bounds (MADBs) in many cases. Finally, several standard numerical examples are presented to show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper investigates the stability problem of Markovian jump systems with multiple delay components and polytopic uncertainties. A new Lyapunov-Krasovskii functional is used for the stability analysis of Markovian jump systems with or without polytopic uncertainties. Two numerical examples are provided to demonstrate the applicability of the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses the static and integral output feedback stabilization problems of continuous-time linear systems with an unknown state/input delay. By combining an augmentation approach and the delay partitioning technique, criteria for static and integral output feedback stabilizability are proposed in terms of nonlinear matrix inequalities with a free parameter matrix introduced. These new characterizations possess a special structure, which leads to linearized iterative computation. The effectiveness and merits of the proposed approach are shown through numerical examples. [Copyright &y& Elsevier]

This paper introduces an effective approach to studying the stability of recurrent neural networks with a time-invariant delay. By employing a new Lyapunov¿Krasovskii functional form based on delay partitioning, novel delay-dependent stability criteria are established to guarantee the global asymptotic stability of static neural networks. These conditions are expressed in the framework of linear matrix inequalities, which can be verified easily by means of standard software. It is shown, by comparing with existing approaches, that the delay-partitioning projection approach can largely reduce the conservatism of the stability results. Finally, two examples are given to show the effectiveness of the theoretical results. [Copyright &y& Elsevier]

This paper focuses on stabilization of second-order oscillatory systems using both feedback control and intentionally introduced time delay. The argument principle is employed as a key technique to divide the parameter space of time delay and controller gain into several regions. Every admissible value in these regions moves the poles of the closed-loop system towards the left of the complex plane such that stability improvement is achieved. The concept of potent asymptotic stability is first introduced, referring to the property that all the poles of the closed-loop system are stable and lie on the left of open-loop system poles in the complex plane. Analytical characterizations on parameter pairs of time delay and controller gain that result in potent asymptotic stability are established. All the poles and corresponding root locus with respect to gain are examined. Numerical examples and simulations are given to illustrate the usefulness and merits of the theoretical results. [ABSTRACT FROM AUTHOR]

This study addresses the positive filter design problem for continuous‐time positive Markov jump linear systems (PMJLSs). Based on the necessary and sufficient condition for L1 ‐gain performance, two sufficient conditions to design positive full‐order and reduced‐order L1 ‐filters for PMJLSs are provided in terms of linear programming, respectively. A practical numerical example of an isotropic, homogeneous and unidimensional aquifer is presented at last to show the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

This study introduces a problem of positive L1 filter design for positive piecewise homogeneous Markovian jump Takagi–Sugeno (T–S) fuzzy systems. The difference between the existing achievements is that the considered transition rate of the positive Markovian jump system is time‐varying. This time‐varying nature is finite piecewise homogeneous. The time variation of the transition rate is characterised by two cases: stochastic variation and arbitrary variation. First of all, sufficient conditions are obtained for stochastic stability and L1 performance under the transition rate in a manner of stochastic variation and arbitrary variation by means of choosing a linear co‐positive Lyapunov function. Then, based on the obtained achievements, the problem of positive L1 filter design for the positive piecewise homogeneous Markovian jump T–S fuzzy system is studied. All the mentioned problems in this study can be solved by linear programming. Finally, a biological model is proposed to illustrate the effectiveness of theoretical results. [ABSTRACT FROM AUTHOR]

This paper addresses the stochastic stability problem of positive Markov jump linear systems (PMJLSs). A necessary and sufficient condition of stochastic stability for PMJLSs is given which can be checked by solving linear programming feasibility problems due to the positivity property. A common co-positive Lyapunov function is constructed to solve the problem, and the equivalence among stochastic stability, 1-moment stability and exponential mean stability is proved afterwards. Considering the uncertain transition rates situation, PMJLSs with partially known transition rate matrix are investigated, and a necessary and sufficient condition for robust stochastic stability is proposed in linear programming form. Numerical examples are presented to show the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

Production of nuclear donor cells with a high percentage of desired modifications is a critical step in the successful generation of genetically modified pigs through somatic cell nuclear transfer (SCNT). The CRISPR/Cas9 system has been used for efficient modification of the nuclear DNA in eukaryotic cells, including porcine cells. However, in vitro modified cells are often phenotypically indistinguishable from unmodified cells, hampering their enrichment. Here we investigate a dual fluorescence selection system for the efficient enrichment of porcine embryonic fibroblasts (PEFs) with CRISPR/Cas9-induced chromosomal deletions. Enrichment of cells with 170 bp deletions reached a frequency of 74%, whilst enrichment of cells with a larger 5 kb deletions achieved a frequency of 46%. This demonstrates the utility of a dual fluorescence reporter as an attractive tool for improving the efficiency of generating genome edited pigs. [ABSTRACT FROM AUTHOR]

This study is concerned with H ∞ control problems for positive systems with time delays using dynamic output feedback. Novel bounded real lemma for continuous‐time systems with time delays is first presented, which shows one of the remarkable properties of diagonal positive definite matrix solutions to linear matrix inequalities for positive systems. The proposed results reveal that H ∞ norms of positive systems with time delays in state and output equations are equivalent to that of the corresponding systems with zero delays. The positivity preserving H ∞ control problem by means of dynamic output feedback is also considered, and thus necessary and sufficient conditions in the forms of matrix equalities are established for the solvability of such problem. The desired controller gains can be obtained by means of cone complementarity linearisation techniques. A numerical example is finally given to illustrate the effectiveness of the obtained results. [ABSTRACT FROM AUTHOR]

Summary: In this work, the problem of adaptive state regulation is addressed via output feedback for a wide class of large‐scale systems with strongly interconnected time‐delay nonlinearities. A design approach of partially decentralized adaptive controller is proposed, which gives a novel pair of reduced‐order observer and controller with nonidentifier‐based double adaptive gains. Compared with the existing results, the growth restrictions imposed on the interconnections are relaxed, where the growth rate includes not only an unknown constant but also the nonpolynomial functions of system output. The double dynamic gains are capable of compensating both the uncertain nonpolynomial growth rate and the unknown time‐varying delay. By constructing novel Lyapunov–Krasovskii functionals and combining dynamic‐scaling technique with Barbălat's lemma, it is shown that global adaptive state asymptotical regulation is achieved, that is all the closed‐loop signals are bounded, and the states of system and observer tend to zero as time goes to infinity. Finally, a simulation example is given to illustrate the proposed control scheme is independent of time delay and well universal. [ABSTRACT FROM AUTHOR]

Abstract: This paper revisits the problem of stability analysis for linear discrete-time systems with time-varying delay in the state. By utilizing the delay partitioning idea, new stability criteria are proposed in terms of linear matrix inequalities (LMIs). These conditions are developed based on a novel Lyapunov functional. In addition to delay dependence, the obtained conditions are also dependent on the partitioning size. We have also established that the conservatism of the conditions is a non-increasing function of the number of partitions. Numerical examples are given to illustrate the effectiveness and advantage of the proposed methods. [Copyright &y& Elsevier]

In this paper, for the purpose of improving the energy efficiency of the industrial sensor networks, we investigated the event-based H∞ filtering problem for a class of discrete-time nonlinear sensor network systems with time-varying delay, packet dropout, and multiplicative noises. Instead of traditional time-triggered communication mechanism, the event-triggered strategy is adopted in industrial sensor network, which could not only reduce the transmission frequency of the sensor measurement output, but also guarantee the prescribed filtering performance, if only the threshold in the event-triggered function is chosen suitably. The time-varying delay characteristic of systems is considered with the event-triggered strategy, which has seldom been studied due to the complexity of time-varying delay and event-triggered strategy. The most common network-induced phenomenon of packet dropout in industrial sensor network is described. The purpose is to design a filter satisfying exponentially stable and H∞ indexes. The main result is that sufficient conditions are established, guaranteeing our proposed filter satisfying filtering performance constraints, and the parameters of filter could be got through the derived linear matrix inequality (LMI), if only it is feasible. At last, the filtering approach is demonstrated by a simulation. [ABSTRACT FROM AUTHOR]

This paper focuses on the problem of reachable set estimation for discrete-time switched positive systems under two possible classes of exogenous disturbance. The multiple linear copositive Lyapunov function approach is applied to determine the bounding hyper-pyramids for the reachable set. Based on some Lyapunov-based inequalities and the linear version of the S-procedure technique, the bounding hyper-pyramids for the reachable set can be determined by solving a set of inequalities. Two optimisation methods are adopted to make the bounding hyper-pyramids as small as possible. Genetic Algorithm (GA) is utilised to search for the optimal value of the decision variables in the obtained inequalities. Finally, numerical examples are given to illustrate the effectiveness of the theoretical findings. [ABSTRACT FROM AUTHOR]

The present aimed to study if porcine circovirus type 2 (PCV2), which adhered to zona pellucida (ZP), was able to enter mature porcine oocytes with intact and damaged ZP. Four groups, including uninfected ZP-intact oocytes (UOZI), uninfected ZP-damaged oocytes (UOZD), PCV2-infected ZP-intact oocytes (POZI), and PCV2-infected ZP-damaged oocytes (POZD) were studied. The oocytes were incubated with 1 mL minimum essential medium, containing 3.1 × 10 8 copies of PCV2 DNA for 1 hour. Mechanical procedure of the insertion by microneedle induced injuries to the ZP of porcine oocytes. At the blastocyst stage, the percentage of PCV2-infected embryos and the ratio of viral antigen-positive cells per embryo were determined by indirect immunofluorescence. To assess the effect of ZP injury on the developmental competence and quality of porcine PCV2-infected oocytes after parthenogenetic activation, blastocyst formation rates and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling staining were analyzed. Moreover, real-time polymerase chain reaction was used to evaluate the expression of genes related to apoptosis and pluripotency at different developmental stages. The results of indirect immunofluorescence showed that only POZD group presented PCV2-infected embryos and viral-positive cells. The blastocyst rate of POZD group dropped down to approximately half of POZI group's (7.1 ± 1.5 vs. 14.5 ± 3.3). At the blastocyst stage, ZP injury increased apoptotic index of PCV2-infected embryos. The relative expression levels of Caspase 3 were higher in POZD group than the ones in POZI group at the two- and four-cell stages (not statistically significant). Compared with the one in POZI group, the ratio of antiapoptotic Bcl-xl gene to proapoptotic Bax gene, an indicator of the ability to resist apoptosis, was lower in POZD group at the one-cell stage, but higher at the two- and four-cell stages. Expression levels of Oct4 and Nanog associated with pluripotency were lower in POZD group than the ones in POZI group at the morula stage (not statistically significant). Noteworthily, the expression of Nanog was significantly lower in POZD group versus POZI group (P < 0.05), whereas relative expression of Oct4 was significantly higher in the former at the blastocyst stage (P < 0.01). In conclusion, PCV2, which attached to ZP, was able to enter mature porcine oocytes with damaged ZP and subsequently reduced the developmental competence and quality of the oocytes after parthenogenetic activation. [ABSTRACT FROM AUTHOR]