Robust Fault Detection of Switched Linear Systems with State Delays

This correspondence deals with the problem of robust fault detection for discrete-time switched systems with state delays under an arbitrary switching signal. The fault detection filter is used as the residual generator, in which the filter parameters are dependent on the system mode. Attention is focused on designing the robust fault detection filter such that, for unknown inputs, control inputs, and model uncertainties, the estimation error between the residuals and faults is minimized. The problem of robust fault detection is converted into an H infin-filtering problem. By a switched Lyapunov functional approach, a sufficient condition for the solvability of this problem is established in terms of linear matrix inequalities. A numerical example is provided to demonstrate the effectiveness of the proposed method

Miniature High-Sensitivity High-Temperature Fiber Sensor with a Dispersion Compensation Fiber-Based Interferometer

A miniature high-sensitivity, high-temperature fiber sensor with an interferometer based on a bare small-core-diameter dispersion compensation fiber (DCF) is reported. The sensing head is a single-mode-fiber (SMF) DCF configuration formed by a 4 mm long bare DCF with one end connected to the SMF by a fusion splicing technique and the other end cleaved. Due to the large mode index difference and high thermo-optic coefficient induced by two dominative interference modes, a miniature high-temperature fiber sensor with a high sensitivity of 68.6 pm/°C is obtained by monitoring the wavelength shift of the interference spectrum. This type of sensor has the features of small size, high sensitivity, high stability, simple structure, and low cost

Street art as a way to enhance the vitality of Uurban public spaces

Street art is a unique artistic behavior that takes place in the urban public space. Its uniqueness is not only manifested in the form of immediacy, participation, and mobility, but also has a great value to enhance space dynamism, increase human interaction, and shaping the spirit of place. In most Chinese cities, street art is often equated with "fraud", which not only hampers the development of street art, but also hinders the promotion of vitality of public space, for a livable and lively city, the public space should not be merely a purely physical space, but should be the sum of the spirit of the place and the vitality of the space. The research question of this paper is: how to reduce the external negative effects of street art and actively shape and regenerate the vitality of urban public space? Research based on literature review and the summary, first of all, review and define the concept of "street art", and carries on the classification, it is believed that street art can change from "urban problem" to "urban landscape", then, the relationship between "street art" and "urban public space vitality" is discussed, performance analysis found a busker behavior can not only enhance the vitality of the public space (one-way intervention), also can attract audience participation, through the interaction with the audience to arouse public space activity (two-way intervention). And then from the perspectives of government, NGO and ordinary citizens, multi-dimensional detailed analysis the art management experience on the streets of Taipei, found that through the government management, system design, the multi-agent organization and the public participation to cultivate a variety of means such as, the urban public space of street art promotion activity provides effective guarantee system and management, and reduce the street art of the outer space of the city has negative effects. Based on this, the paper puts forward the spatial layout pattern of “centralized and decentralized complementarity”, the behavioral restraint mechanism of “rigidity and elasticity”, and the multi-agent intervention management of “organization and self-organization”,“Planning for Positive Public Opinion and Strict Enforcement of Law Enforcement” and other planning strategies. This paper argues that, by using the experience of management of Taipei street artists, from space, organization, policy formulation, implementation and operation aspects improve mainland China the level of city governance, with a view to providing references for the regeneration and shaping of the vitality of urban public space in China, and to provide a useful reference for the management of street artists

Alpha-decay half-lives and Q_alpha values of superheavy nuclei

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated based on a unified fission model (UFM) where a new method to calculate the assault frequency of alpha-emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha-decays. It is found that the half-lives become more and more insensitive to the Q_alpha values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is suggested to compute the Q_alpha values for the nuclei with Z > 92 and N > 140 with a good accuracy, according to which the long-lived SHN should be neutron rich. With Q_alpha values from this formula as inputs, we predict the half-lives of isotopes of Z = 117, which may be useful for experimental identication in the future.Comment: 7 pages, 3 figure

Temperature- and Phase-Independent Lateral Force Sensor based on a Core-Offset Multi-Mode Fiber Interferometer

A novel lateral force sensor based on a core-offset multi-mode fiber (MMF) interferometer is reported. High extinction ratio can be obtained by misaligning a fused cross section between the single-mode fiber (SMF) and MMF. With the variation of the lateral force applied to a short section of the MMF, the extinction ratio changes while the interference phase remains almost constant. The change of the extinction ratio is independent of temperature variations. The proposed force sensor has the advantages of temperature- and phase-independency, high extinction ratio sensitivity, good repeatability, low cost, and simple structure. Moreover, the core-offset MMF interferometer is expected to have applications in fiber filters and tunable phase-independent attenuators

Core-Offset Small-Core-Diameter Dispersion Compensation Fiber Interferometer and its Applications in Fiber Sensors

We propose a core-offset small core diameter dispersion compensation fiber (DCF) interferometer and investigate its applications in fiber sensors. If the transverse force is applied to a short section of the DCF, there is almost no crosstalk on the transmission spectrum between the extinction ratio variation induced by the transverse force and the wavelength shift caused by the longitudinal strain or ambient temperature, which can be applied to measure both transverse and longitudinal strain, or both transverse strain and temperature, simultaneously. The proposed sensors have the advantages of low cost, simple and compact structure, and good reproducibility