Search results for "fuzzy"

Stability analysis and controller design for a class of T-S fuzzy Markov jump system with uncertain expectation of packet dropouts

2013

This paper is concerned with an H∞ control for a class of Takagi-Sugeno (T-S) fuzzy Markov jump system under unreliable communication links. It is assumed that the transition probabilities determining the dynamical behavior of the underlying system are partially unknown and the communication links between the plant and the controller are imperfect (the packet dropouts occur intermittently). In this paper, a more practical scenario is considered in the setting, i.e., the expectation of packet losses represented as a description of Bernoulli-distributed stochastic process is uncertain. Attention is focused on the design of H∞ controllers such that the closed-loop system is stochastically stab…

Trajectory Decentralized Fuzzy Control of Multiple UAVs.

2008

This paper considers a complete position and heading rate control system for multiple unmanned aerial vehicles (UAVs) with constant altitude. A decentralized trajectory planning algorithm is proposed, where the UAVs will avoid collisions while moving. In order to stabilize the UAVs in the reference planned trajectories and ensure the boundedness of the control velocities, a fuzzy control law is proposed with Lyapunov's stability proof. Simulation experiments developed in Matlab environment confirm the effectiveness and the robustness of the proposed control algorithm with respect to possible turbulence disturbances perturbing the nominal motion of the UAVs.

Chaos Synchronization Based on Unknown Input Proportional Multiple-Integral Fuzzy Observer

2013

Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2013/670878 Open Access This paper presents an unknown input Proportional Multiple-Integral Observer (PIO) for synchronization of chaotic systems based on Takagi-Sugeno (TS) fuzzy chaotic models subject to unmeasurable decision variables and unknown input. In a secure communication configuration, this unknown input is regarded as a message encoded in the chaotic system and recovered by the proposed PIO. Both states and outputs of the fuzzy chaotic models are subject to polynomial unknown input with kth derivative zero. Using Lyapunov stability theory…

Dynamic Output-Feedback Passivity Control for Fuzzy Systems under Variable Sampling

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/767093 Open Access This paper concerns the problem of dynamic output-feedback control for a class of nonlinear systems with nonuniform uncertain sampling via Takagi-Sugeno (T-S) fuzzy control approach. The sampling is not required to be periodic, and the state variables are not required to be measurable. A new type fuzzy dynamic output-feedback sampled-data controller is constructed, and a novel time-dependent Lyapunov-Krasovskii functional is chosen for fuzzy systems under variable sampling. By using Lyapunov stability theory, a sufficie…

USE OF FUZZY NEURAL NETWORKS IN MODELING RELATIONSHIPS OF HPV INFECTION WITH APOPTOTIC AND PROLIFERATION MARKERS IN POTENTIALLY MALIGNANT ORAL LESIONS

2005

To evaluate in oral leukoplakia the relationship between HPV infection and markers of apoptosis (bcl-2, survivin) and proliferation (PCNA), also conditionally to age, gender, smoking and drinking habits of patients, by means of Fuzzy neural networks (FNN) system 21 cases of oral leukopakia, clinically and histologically diagnosed, were examined for HPV DNA presence, bcl-2, survivin and PCNA expression. HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR: MY09-MY11/GP5-GP6), and the HPV genotype determined by direct DNA sequencing. All markers were investigated by means of standardised immunohistochemistry procedure. Data were analysed by chi-square test, crude OR an…

A multi-criteria approach for the group assessment of an academic course: A case study

2015

The present paper aims at proposing a structured methodology to evaluate the results of an academic training course addressed to postgraduate students. The evaluation process intends to identify the efficacy of an education course bymeans of acomparison between the general objectives and the results expected by the students. Since the evaluated aspects by the students, detected by means of questionnaires, are both quantitative and qualitative, the proposed methodology is based on the analytic hierarchy process (AHP). In order to facilitate the evaluation process, answers have been modelled by means of linguistic variables. In particular, different evaluation scales have been used and each on…

Many-valued Logics and Quantum Mechanics

2013

Determinants of translation-firm survival: A fuzzy set analysis

2016

Abstract This article presents an empirical analysis of determinants of the survival of firm or self-employed workers in the Spanish translation sector. In the midst of a global downturn, the survival of firm and self-employed workers is a key factor for the progress of the economy and for a better and more stable future. The analysis explores the combination of variables including human capital, contingency and economic investment that potentially drive translation and interpreting firms to survive. The study performs a comparative qualitative analysis using a fs/QCA methodology and identify seven combinations of causes that lead to the outcome. The results show that different causal paths…

Exploring the viability of equity crowdfunding as a fundraising instrument: A configurational analysis of contingency factors that lead to crowdfundi…

2020

Abstract With the growth in the use of crowdfunding platforms for fundraising, analysis of the key factors associated with successful crowdfunding has emerged as an interesting and oft-researched topic. Nonetheless, the equity crowdfunding market is still relatively under researched. The purpose of this paper is to explore how contingency factors combine and causally connect in leading to possible success or failure in equity crowdfunding rounds. To reach this goal, a configurational approach was chosen. Qualitative comparative analysis (QCA) is a suitable method for this topic because of its ability to identify and assess different combinations of conditions that explain certain outcomes. …

Do Financial Crises Moderate Entrepreneurial Recipes? A Comparative Fuzzy Analysis

2016

ABSTRACTThis study performs a fuzzy set qualitative comparative analysis (fsQCA) on entrepreneurial recipes. The research focuses on the moderating role of the 2007 financial crisis on the antecedents of entrepreneurship. Standard regressions analysis proves insufficient to uncover asymmetrical and complex relationships that explain the effect of credit constraints on new business. Empirical results on longitudinal data suggest that the crisis moderated entrepreneurial recipes in Spain. This research contributes to QCA analysis by studying moderation effects on time-series data.