In this paper, input-to-state stability (ISS) for discrete-time switched nonlinear time-varying (SNTV) systems is investigated. Starting with discrete-time nonlinear time-varying (NTV) systems, some ...improved sufficient conditions are proposed to verify the ISS of systems by using the weak implication-form ISS (WI-ISS) Lyapunov function, weak dissipative-form ISS (WD-ISS) Lyapunov function, and interval descent technique. Then, the results obtained are extended to study the ISS of discrete-time SNTV systems, several relaxed conditions are given by using piecewise WI-ISS and WD-ISS Lyapunov functions, minimum dwell time, and infinite switching methods, respectively. Comparing with the existing results, the obtained conditions release the requirement on negative definiteness of the differences of (piecewise) Lyapunov functions, moreover, all subsystems are allowed to be unstable in the case of infinite switching. Finally, a numerical example is given to illustrate the theoretical results.
In this paper, we present Lyapunov characterizations of the global asymptotic stability, the input-to-state stability (ISS), and the incremental input-to-state stability (δ-ISS) for discrete-time ...nonlinear systems with uncertain and time-varying time delays. We provide necessary and sufficient conditions for the global asymptotic stability and for the ISS and sufficient conditions for the δ-ISS, in terms of discrete-time Lyapunov-Krasovskii functionals. In particular, the Lyapunov characterization of the notion of δ-ISS is motivated by problems concerning the construction of discrete abstractions approximating discrete-time nonlinear systems. Uncertain and time-varying time delays occur very frequently, for instance, in networked control systems. Examples are included that illustrate the proposed methodologies.
Background and purpose: Human papillomavirus (HPV) is a tiny virus of the papillomavirus family that infects skin and mucosal cells and can be transmitted through sexual intercourse. In general, all ...STIs (Sexually Transmitted Diseases) have negative psychological effects. In addition, the diagnosis of HPV has a wide impact on the mental health of patients and their sexual activity, which may make the patient feel ashamed and disrupt the patient's relationship with his life partner. The level of anxiety and sexual satisfaction has not been measured in women with HPV in Iran, yet. Therefore, the purpose this study was to investigate their awareness of the HPV virus and its relationship with the level of anxiety and sexual satisfaction of the patients with a positive HPV test. Materials and methods: Cross-sectional design was employed in this study. Women who had a positive HPV test at the first visit after the HPV test result were recruited. All patients who visited two different academic and private centers between September 2018 and March of the same year after receiving their HPV test results were involved in the study. First, their consent was obtained to involve in this study. Then, a demographic questionnaire, Beck's anxiety questionnaire, sexual satisfaction index and HPV awareness questionnaire were completed. Data were analyzed using SPSS version 24 software, and P value less than 0.05 was considered significant. Results: 159 participants with an average age of 32.3 years and a standard deviation of 6.64 years were included in the analysis. The results showed that age has a reverse and significant relationship with the level of knowledge of HPV. The awareness of HPV decreases as the age of the participants increases(P<0.001). With the increase of the education level, the level of awareness among individuals also increased significantly (P<0.001). Moreover, individuals who engaged in their first sexual intercourse at an older age displayed higher levels of awareness(P=0.007) and lower levels of anxiety(P=0.018). results also showed that There was no significant difference at the level of anxiety between different jobs, the level of awareness with the level of anxiety and/or lack of sexual satisfaction(P>0.05). Additionally, no significant relationship was found between the level of anxiety and sexual dissatisfaction, age and the level of anxiety and/or sexual dissatisfaction (P>0.05). Conclusion: In general note, the level of population’s knowledge about HPV is low. Healthcare workers and medical students have better knowledge of the subject but it is still insufficient. Patients should also be referred to a psychiatrist or other mental health professionals for their anxiety control. Establishing a trust-based relationship between the doctor and the patient is essential for maintaining the patient's desire to continue the treatment.
We study the problem of stabilizing a switched linear system with a completely unknown disturbance using sampled and quantized state feedback. The switching is assumed to be slow enough in the sense ...of combined dwell time and average dwell time, each individual mode is assumed to be stabilizable, and the data rate is assumed to be large enough but finite. By extending the approach of reachable-set approximation and propagation from an earlier result on the disturbance-free case, we develop a communication and control strategy that achieves a variant of input-to-state stability with exponential decay. An estimate of the disturbance bound is introduced to counteract the unknown disturbance, and a novel algorithm is designed to adjust the estimate and recover the state when it escapes the range of quantization.
This paper considers integral input-to-state stability (iISS) for a class of hybrid time-delay systems. Discrete dynamics includes impulsive and switching signals, and continuous dynamics is not ...necessarily stable. Based on multiple Lyapunov–Krasovskii functionals, a dwell-time bound is explicitly given to guarantee iISS of the hybrid delayed system. Compared with existing results on related problems, the obtained stability criteria can be applied to a larger class of hybrid delayed systems. Moreover, the obtained dwell-time bound is less conservative than existing ones. At last, an example related to networked control systems (NCSs) is provided to illustrate the effectiveness of the proposed result.
•This study proposes an analytical framework combining the expectation-confirmation model (ECM), information system success (ISS) model, TAM, and the need for interaction with a service ...employee.•Analysis of data reveals that information quality and service quality positively influence consumers’ satisfaction, and that perceived enjoyment, perceived usefulness, and perceived ease of use are significant predictors of continuance intention.•The findings further show that the need for interaction with a service employee moderates the effects of perceived ease of use and perceived usefulness on satisfaction.
Chatbots are mainly text-based conversational agents that simulate conversations with users. This study aims to investigate drivers of users’ satisfaction and continuance intention toward chatbot-based customer service. We propose an analytical framework combining the expectation-confirmation model (ECM), information system success (ISS) model, TAM, and the need for interaction with a service employee (NFI-SE). Analysis of data collected from 370 actual chatbot users reveals that information quality (IQ) and service quality (SQ) positively influence consumers’ satisfaction, and that perceived enjoyment (PE), perceived usefulness (PU), and perceived ease of use (PEOU) are significant predictors of continuance intention (CI). The need for interaction with an employee moderates the effects of PEOU and PU on satisfaction. The findings also revealed that satisfaction with chatbot e-service is a strong determinant and predictor of users’ CI toward chatbots. Thus, chatbots should enhance their information and service quality to increase users’ satisfaction. The findings imply that digital technologies services, such as chatbots, could be combined with human service employees to satisfy digital users.
Initial trust represents the trust that develops upon first use of a product. It is built on the basis of the net effect of factors that stimulate as well as inhibit it. Future transactions require ...less consumer effort after initial-trust formation. Despite being recognized as an important factor affecting the adoption of innovations, initial trust has been not been greatly explored by prior scholars. The present study remedies this gap by invoking the information systems success (ISS) model, transaction cost economics (TCE) theory, and the IT continuance model to propose a two-step framework that includes the antecedents of a pre-adoption factor, such as initial trust, and post-adoption factors, such as confirmation, perceived usefulness, satisfaction, and continuation intention toward mobile-based payments. Cross-sectional data of 954 first-time mobile-wallet users are analyzed to test the framework. The study findings suggest that information and service quality positively influence initial trust, which, in turn, has a positive association with confirmation and perceived usefulness. Results also reveal a positive relationship between perceived usefulness and continuation intention. These results pave the way for making useful recommendations for future researchers. The study also discusses various inferences that can improve managerial efficacy in promoting the use of mobile-based payment methods.
•We empirically tested antecedents and outcomes of initial trust.•The ISS model, TCE theory, and IT continuance model were used as theoretical lenses.•Information and service quality positively correlated with initial trust.•Initial trust positively correlated with confirmation and perceived usefulness.•Perceived usefulness positively correlated with continuation intention.
Zusammenfassung
Die Geschichte der Raumfahrt ist bisher kürzer als eine durchschnittliche Lebensspanne. Seit 1961 sind erst etwa 600 Menschen jemals im Orbit gewesen. Die extremen Verhältnisse des ...Weltalls erweitern alle uns auf der Erde bekannten Wissenschaften um eine neue astronomische Dimension und erfordern für einen dauernden Aufenthalt viele Schutzmaßnahmen und Anpassungen. Es ist absehbar, dass die Fortschritte der bemannten Raumfahrt, insbesondere künftige neue Mondmissionen oder gar Flüge zum Mars in den nächsten Jahrzehnten große Impulse auf dem Gebiet der Astropharmazie und Astrotoxikologie bringen werden.
Summary
The history of spaceflight has been shorter than an average lifespan. Since 1961, around 600 humans have ever been in orbit. The extreme conditions of space add a new astronomical dimension to all the sciences known to us on Earth and require many protections and adaptations for a permanent space stay. It is foreseeable that the progress of manned space spaceflight, especially future new moon missions or even flight to Mars, will bring great impulses to the field of astropharmacy and astrotoxicology in the next decades.
Seit dem ersten Orbitalflug von Juri Gagarin im April 1961 sammelt die Menschheit Erfahrung mit dem Leben im All. Trotzdem waren bisher erst etwa 600 Menschen im Weltraum. Während die ersten Weltraumflüge nur wenige Tage andauerten, sind inzwischen durch die russische Raumstation Mir Mitte der 1980er Jahre und seit der Jahrtausendwende durch die internationale Raumstation ISS längere Besuche im Weltraum scheinbar Routine geworden. Es ist absehbar, dass in der Zukunft, nicht zuletzt durch private Initiative, mehr Menschen Weltraumerfahrung machen werden. So hat der Multimilliardär Elon Musk 2002 SpaceX gegründet mit dem klaren Ziel, eines Tages eine Marskolonie zu gründen. Zukünftige Aufenthalte in einer ständigen Mondstation oder Flüge zum Mars werden mit den Bedingungen des Weltalls, insbesondere der geringen Schwerkraft, der hohen Strahlung, der großen Temperaturunterschiede und des Vakuums völlig neue Herausforderungen an das Fachgebiet der Pharmazie und Toxikologie stellen.
•A new source of high spatial and multispectral nighttime light (NTL) imagery is introduced.•The ability of SDGSAT-1 to reflect spatial variability in NTL across land-use types outperforms than ...ISS-P, Luojia1-01 and VIIRS-DNB NTL imagery.•Three SDGSAT NTL spectral indexes are analyzed whether they enhance the NTL variability than that of individual bands.•The potential urban applications of SDGSAT-1 NTL data are discussed.
The successful launch of Sustainable Development Science Satellite 1 (SDGSAT-1) complements the existing nighttime lights (NTL) data with high spatial resolution in the three visible bands (40 m) and the panchromatic band (10 m). This study aimed to evaluate the potentiality of the new NTL imagery – SDGSAT-1 – in revealing the spatial variation in NTL intensity. We compared the NTL image from SDGSAT-1 with other existing NTL datasets: the Visible infrared Imaging Radiometer Suite-Day Night Band (VIIRS-DNB), Luojia1-1 (LJ1-01), and photographs from the International Space Station (ISS-P) at spatial resolutions of 500 m, 130 m, and 10 m, respectively. Then, we investigated the intraurban NTL spatial variability of eleven urban land-use types with analysis of variance (ANOVA). In addition, we used random forest (RF) regression to analyze the relationship between explanatory factors and NTL variation. The results showed the following: (1) The quality of the SDGSAT-1 NTL image was comparable with ISS-P and better than VIIRS-DNB and LJ1-01 imagery in spectral and spatial resolution. (2) The ability of the RGB bands and grayscale brightness of the SDGSAT-1 NTL image to distinguish various land use types outperformed that of the ISS-P, LJ1-01, and VIIRS-DNB images. (3) The NTL spectral index SONDI, combined with three visible bands, could improve the ability of a single band to show the lighting differences in intraurban areas. (4) The nine variables explained 39.20%–42.30% of the NTL intensity variability in the four RF models. Road density and public POI density were the most important variables in the red-green and blue bands, indicating that high-pressure sodium and lighting-emitting diode lamps were primarily deployed in the road and public areas, respectively. Meanwhile, the potential applications of SDGSAT-1 NTL imagery were further discussed. Our findings indicate the great potential of SDGSAT-1 NTL imagery for supporting sustainable urban development.
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