Search results for " Time"
showing 10 items of 3005 documents
Application of distributed expert systems to the advanced control of smart houses
2003
Abstract A distributed expert system has been proposed for the smart house control. Its configuration is mainly based on the use of distributed nodes connected by means of a CAN network. This kind of systems allow the implementation of highly flexible control systems capable of adapting themselves to different situations. The expert system used is based on Rule Nets (RN), which are a formalism that seeks to express an automatism in a similar way to as would make it a human being: "IF antecedents THEN consequents". But at the same time Rule nets are a tool for the design, analysis and implementation of rule based systems (RBS), and consist on a mathematic-logical structure which analytically…
Wearable wireless photoplethysmography sensors
2008
Wearable health monitoring sensors may support early detection of abnormal conditions and prevention of their consequences. Recent designs of three wireless photoplethysmography monitoring devices embedded in hat, glove and sock, and connected to PC or mobile phone by means of the Bluetooth technology, are described. First results of distant monitoring of heart rate and pulse wave transit time using the newly developed devices are presented.
Full-wave FDTD design and analysis of wideband microstrip-to-waveguide transitions
2003
Wideband transitions are designed and analysed by using two different approaches of the finite-difference time-domain (FDTD) method, in combination with the theory of nonuniform transmission lines. These transitions consist of a ridged waveguide-based taper between a shielded microstrip and a standard X-band rectangular waveguide. In the first step, a full-wave 2D-FDTD scheme is used to calculate the dispersion characteristics, as well as the geometry dependence of the impedance in the double ridged waveguide. Once these design curves have been obtained, the stepped transmission line transformer theory is used to design the tapers. In a former step, the nonuniform 3D-FDTD technique is appli…
Calculation of the characteristic impedance of microstrips using a full-wave 2-D FDTD scheme
1997
The frequency dependence of the characteristic impedance of microstrip lines has been investigated by many authors using 3D-FDTD formulations. In the present letter, a two-dimensional FDTD scheme is used to calculate both the propagation constant and the characteristic impedance of the fundamental quasi-TEM mode in a microstrip which, in fact, is a hybrid mode. Because of the substantial reduction of computer resources required for the calculations, this method can be used as a design tool. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 16: 58–60, 1997.
Finite-Difference Time-Domain Simulation of Towers Cascade Under Lightning Surge Conditions
2015
In this paper, the simulation of towers cascade under lightning surge conditions is presented. Finite-difference time-domain method is used to solve both the Maxwell's and telegraph equations. Maxwell's equations and the time-domain resistivity model of Darveniza are used to simulate the nonlinear behavior of the grounding system. Telegraph equations are used to describe the propagation in the overhead lines. Multiple ionizations, on different grounding electrodes belonging to various towers, can be implemented simultaneously, without making assumptions on the shape of the ionized areas.
A robust fault detection design for uncertain Takagi-Sugeno models with unknown inputs and time-varying delays
2013
Abstract This paper investigates the problem of robust fault detection system design for a class of uncertain Takagi–Sugeno (T–S) models. The system under consideration is subject to unknown input and time-varying delay. The fault detection system is designed such that the unknown input is thoroughly decoupled from residual signals generated by the fault detection system. Furthermore, the residual signals show the maximum possible sensitivity to the faults and the minimum possible sensitivity to the external disturbances. The model matching approach is utilized to tackle the effects of parametric uncertainties in the model of the system. The design procedure is presented in terms of Linear …
A statistic approach of cables ageing in MV lines on thermal and electrical combined stress
2006
The paper introduces a methodology that through a probabilistic characterisation of load for MV network, and implementing a life model for combined electric and thermal stresses, simulates the process of ageing of the insulating materials evaluating the expected life time of the cable. Such evaluation is necessary to the possibility of assuming less restrictive thermal overloading limits on electrical cables, with the consequential increase on reserve that cables could offer. A numerical example is reported to better explain the methodology
Decoding the Japanese Lean Production System according to a Viable Systems Perspective
2012
The increase in the complexity and variability of the business environment, due to constant and rapid changes in markets, calls for more flexible and effective production systems. Of the most valuable production systems, the Japanese lean production system (LPS) is the best known and studied, but is still not the most widely applied with success outside Japan. The reason for the low level of success of lean production outside its native country is the lack of understanding of the strong interactions which hold between enterprises and business systems. In order to fill this gap in our knowledge, we investigate the systemic interactions according to the Viable System View. To develop our anal…
Improved Planning In-Service Inspections of Fatigued Aircraft Structures Under Parametric Uncertainty of Underlying Lifetime Models
2014
Certain fatigued structures must be inspected in order to detect fatigue damages that would otherwise not be apparent. A technique for obtaining optimal inspection strategies is proposed for situations where it is difficult to quantify the costs associated with inspections and undetected failure. For fatigued structures for which fatigue damages are only detected at the time of inspection, it is important to be able to determine the optimal times of inspection. Fewer inspections will lead to lower fatigue reliability of the structure upon demand, and frequent inspection will lead to higher cost. When there is a fatigue reliability requirement, the problem is usually to develop an inspection…
Evaluation of radiated EMI in 42 V vehicle electrical systems by FDTD simulation
2007
In this paper a full 3D numerical scheme, based on the finite difference time domain method, is used to predict the electromagnetic radiated interference generated by 42 V vehicle power electronic driven electrical loads. An experimental set-up has been arranged on purpose in order to validate the proposed simulation tool. To this aim, the features of a semi-anechoic electromagnetic chamber have been exploited in order to operate in a shielded test site for the measurement of near field radiated emissions. Two different three-dimensional geometrical configurations of realistic vehicle installations of the loads, are studied. A comparative analysis among measured and computed results is perf…