Search

Recently, a polynomials-based integral inequality was proposed by extending the Moon’s inequality into a generic formulation. By imposing certain structures on the slack matrices of this integral inequality, this paper proposes an orthogonal-polynomials-based integral inequality which has lower computational burden than the polynomials-based integral inequality while maintaining the same conservatism. Further, this paper provides notes on relations among recent general integral inequalities constructed with arbitrary degree polynomials. In these notes, it is shown that the proposed integral inequality is superior to the Bessel–Legendre (B–L) inequality and the polynomials-based integral inequality in terms of the conservatism and computational burden, respectively. Moreover, the effectiveness of the proposed method is demonstrated by an illustrative example of stability analysis for systems with additive time-varying delays.

This paper considers a delay-dependent stability criterion for linear systems with multiple time-varying delays. To exploit all possible information for the relationships among the marginally delayed states ( x ( t − τ i M ) , x ( t − τ i + 1 M ) ), the exactly delayed states ( x ( t − τ i ( t ) ) , x ( t − τ i + 1 ( t ) ) ), and the current state x ( t ) for each pair ( i , i + 1 ) of time-varying delays, a delays-dependent region partitioning approach in double integral terms is proposed. By applying the Wirtinger-based integral inequality and the reciprocally convex approach to terms resulted from the region partitioning, a stability criterion is derived in terms of linear matrix inequalities. Numerical examples show that the resulting criterion outperforms the existing one in literature.

The accuracy of a bioassay based on smartphone-integrated fluorescent biosensors has been limited due to the occurrence of false signals from non-specific reactions as well as a high background and low signal-to-noise ratios for complementary metal oxide semiconductor image sensors. To overcome this problem, we demonstrate dual-wavelength fluorescent detection of biomolecules with high accuracy. Fluorescent intensity can be quantified using dual wavelengths simultaneously, where one decreases and the other increases, as the target analytes bind to the split capture and detection aptamer probes. To do this, we performed smartphone imaging-based fluorescence microscopy using a microarray platform on a substrate with metal-enhanced fluorescence (MEF) using Ag film and Al2O3 nano-spacer. The results showed that the sensitivity and specificity of the dual-wavelength fluorescent quantitative assay for the target biomolecule 17-β-estradiol in water were significantly increased through the elimination of false signals. The detection limit was 1pg/mL and the area under the receiver operating characteristic curve of the proposed assay (0.922) was comparable to that of an enzyme-linked immunosorbent assay (0.956) from statistical accuracy tests using spiked wastewater samples. This novel method has great potential as an accurate point-of-care testing technology based on mobile platforms for clinical diagnostics and environmental monitoring.

Probe-mediated fluorescence biosensing methods based on spectrophotometry still have limitations such as detection inaccuracy caused by the occurrence of false signals and lack of simultaneous qualitative and quantitative read-outs with an ultra-low detection limit. Herein, we describe a novel seesawed fluorescence detection strategy based on dual-colour imaging-based quantitation in which the green fluorescence of the capture aptamer decreases and the red fluorescence of the detection aptamer increases simultaneously upon their respective interactions with the target biomolecule. This approach enhances detection accuracy through facilitating identification of probable false-positives in biological samples. Furthermore, combining the seesawed detection scheme with three-dimensional imaging of fluorescence signal enhanced by highly vertical ZnO nanorods increases signal-to-noise ratio, which addresses the limited performance of digital cameras and, in turn, enhances sensitivity and dynamic range. This simple, robust, scalable, imaging-based and label-free fluorescence method allows highly specific and sensitive quantification of biomolecules with excellent reliability.

This paper employs polynomial functions to extend a free-matrix-based integral inequality into a general integral inequality, say a polynomials-based integral inequality, which also contains well-known integral inequalities as special cases. By specially designing slack matrices and an arbitrary vector containing state terms, it reduces to an extended version of Wirtinger-based integral inequality or the free-matrix-based integral inequality. Numerical examples for stability analysis of linear systems with interval time-varying delays show the improved performance of the proposed integral inequality in terms of maximum delay bounds and numbers of variables.

This paper suggests first-order and second-order generalized zero equalities and constructs a new flexible Lyapunov-Krasovskii functional with more state terms. Also, by applying various zero equalities, improved stability criteria of linear systems with interval time-varying delays are developed. Using Wirtinger-based integral inequality, Jensen inequality and a lower bound lemma, the time derivative of the Lyapunov-Krasovskii functional is bounded by the combinations of various state terms including not only integral terms but also their interval-normalized versions, which contributes to make the stability criteria less conservative. Numerical examples show the improved performance of the criteria in terms of maximum delay bounds.

This paper proposes a novel approach called a combined reciprocal convexity approach for the stability analysis of static neural networks with interval time-varying delays. The proposed approach deals with all convex-parameter-dependent terms in the time derivative of the Lyapunov-Krasovskii functional non-conservatively by extending the idea of the conventional reciprocal convexity approach. Based on the proposed technique and a new Lyapunov-Krasovskii functional, two improved delay-dependent stability criteria are derived in terms of linear matrix inequalities(LMIs). Some numerical examples are given to demonstrate the proposed results.

For the stability analysis of discrete time-delay systems, Jensen inequality has been widely used as the method supporting inequalities for summation quadratic functions. It not only requires a smaller number of decision variables than other approaches but also achieves identical or comparable performance behavior. Based on the analysis for the conservatism of Jensen inequality, however, this paper suggests a new summation inequality say an auxiliary-function-based summation inequality. It is verified that the proposed inequality is a generalized form of the novel summation inequality reported recently. Also, an application to stability analysis for discrete time-delay systems is provided.

For the interval time-varying delay systems, Jensen inequality lemma yields some terms with the inverse of convex and squared convex parameters, which often makes it difficult to find their bounds. Recently, reciprocal and second-order reciprocal convexity approaches have been proposed to handle the difficulties with a set of convex parameters and a set of squared convex parameters, respectively, but these approaches do not investigate the relation between the two sets. This paper offers much tighter bounds of those terms utilizing the relations among the two sets with the lower bound lemma. Based on the new approach and Lyapunov theory, less conservative stability criteria for time delay systems are developed. To show the effectiveness of the new approach, two numerical examples are given.

This paper considers the stability problem of recurrent neural networks with interval time-varying delays. Based on a new augmented Lyapunov-Krasovskii functional that contains four triple integral terms and additional terms obtained from the activation function condition, a stability condition is derived in terms of linear matrix inequalities (LMIs). Also, a further improved stability criterion is derived by bounding the derivative of a special case of the proposed Lyapunov-Krasovskii functional based on a new inequality proposed in Seuret and Gouaisbaut (2013) 27]. A numerical example shows the improvement of the proposed approach both in terms of computational complexity and conservatism.

Finding integral inequalities for quadratic functions plays a key role in the field of stability analysis. In such circumstances, the Jensen inequality has become a powerful mathematical tool for stability analysis of time-delay systems. This paper suggests a new class of integral inequalities for quadratic functions via intermediate terms called auxiliary functions, which produce more tighter bounds than what the Jensen inequality produces. To show the strength of the new inequalities, their applications to stability analysis for time-delay systems are given with numerical examples.

Jensen inequality has become a powerful tool of supporting summation inequalities for quadratic functions in order to obtain stability criteria for time-delayed systems since it achieves remarkable performance with a small number of decision variables. This paper suggests a new summation inequality for quadratic functions based on an auxiliary function, which is superior to the Jensen inequality. To demonstrate the superiority of the new inequality, its application to stability analysis for discrete-time delay system is provided with a simple numerical example.

This paper analyzes delay-dependent robust stability and H"~ performance of linear systems with an interval time-varying delay, based on a new Lyapunov-Krasovskii functional containing new triple integral terms. The time derivative of the Lyapunov-Krasovskii functional produces not only the strictly proper rational functions but also the non-strictly proper rational functions of the time-varying delays with first-order denominators. The combinations of the rational functions are directly handled via the Jensen inequality lemma and the lower bound lemma for reciprocal convexity, whereas such combinations were approximated in the literature. The proposed criteria become less conservative with the significantly smaller number of decision variables than the existing criteria, which will be demonstrated by some numerical examples.

This study estimates the gross quantity of discarded fishing traps and gill-nets in the coastal waters of South Korea. Using regression analysis it is estimated that 11,436 t of traps and 38,535 t of gill-nets are abandoned annually. Experts on marine debris recommend replacement of traditional fishing gears with eco-friendly designs and establishment of incentive programmes for the fishermen in order to promote eco-friendly gear designs.

In this note, the state-feedback stabilization for continuous-time Takagi-Sugeno (T-S) fuzzy systems is addressed, where the fuzzy weighting functions are assumed to be differentiable and their ranges of variation are possibly bounded by some parameters. By utilizing the matrix elimination lemma and introducing a polyhedral partition to the range of the fuzzy weights, the quadratically parameterized condition is transformed to being piecewise linear in both the fuzzy weights and their derivatives. Then, a switching control based on the partition is considered, by utilizing the extreme points in each partition to address the constraints of the fuzzy weights and their derivatives. The simulation shows that finer subdivision in the partition leads to better stability and stabilization margins.

Genetically modified mesenchymal stem cells (MSCs) are potentially valuable tools for the novel treatment of human illnesses. Here, we investigated whether gene transfers by self-complementary adeno-associated viruses (scAAV) lead to promising genetic modification in human bone marrow and umbilical cord blood MSCs. Of the various scAAVs, scAAV2, and scAAV5 effectively and safely expressed transgenes in both hMSCs. Transduction efficiency with scAAV2 at 1000 multiplicity of infection was 66.3 ± 9.4% and 67.6 ± 6.7% in bone marrow and umbilical cord blood MSCs, respectively. A co-infection study showed that the distinct scAAV2 and scAAV5 can effectively express different transgenes in the same hMSC. hMSCs transduced by scAAVs showed long-term gene expression for three months in rat brains. Genetic modification by scAAVs did not affect osteogenic differentiation of hMSCs. Therefore, the present study strongly supports the promising potential of scAAVs as a technical platform for safe, long-term transgene expression in hMSCs.

We present a case-based approach for natural language interface to a UNIX system with automatic programming ability. Natural language commands are analyzed by case-based parsing and then transformed into UNIX shell-scripts by case-based planning with derivational analogy. Our system, a Dialogue Interface to uNIX (DINX) demonstrates that natural language parsing should be augmented with automatic programming to provide efficient and user friendly interfaces. We suggest case-based reasoning as a unifying framework to combine natural language parsing with automatic programming in a synergistic way.