Search results for "Systems engineering"
showing 10 items of 1230 documents
Probabilistic characterization of nonlinear systems under Poisson white noise via complex fractional moments
2014
In this paper, the probabilistic characterization of a nonlinear system enforced by Poissonian white noise in terms of complex fractional moments (CFMs) is presented. The main advantage in using such quantities, instead of the integer moments, relies on the fact that, through the CFMs the probability density function (PDF) is restituted in the whole domain. In fact, the inverse Mellin transform returns the PDF by performing integration along the imaginary axis of the Mellin transform, while the real part remains fixed. This ensures that the PDF is restituted in the whole range with exception of the value in zero, in which singularities appear. It is shown that using Mellin transform theorem…
FIR Kramers–Kronig transformers for relaxation data conversion
2006
It is shown that relaxation data conversion by the Kramers-Kronig (KK) relations can be treated as a filtering problem of band-unlimited relaxation signals in the Mellin transform domain. Based on this concept, KK relations are implemented in the form of FIR filters with the logarithmic sampling. It is demonstrated that KK transformers have sampling rate dependent impulse and frequency responses and only calculation of the imaginary part from the real part can be implemented by a computationally realisable filter. The performance of different types of transformers is studied.Approximately inversely proportional relationship is established between the error and the frequency range of input s…
Agency and Presence: A Common Dependence on Subjectivity?
2006
This paper argues that presence, as shown in virtual environments, can usefully be seen as comprising various subtypes and that these in turn may have common conceptual and ontological features with a sense of agency as defined by Russell (1996, Agency: Its Role in Mental Development, Erlbaum.). Furthermore, an analysis of Russell's characterization of the concept of agency may be useful for acquiring insight into the sense of presence itself and the variables affecting it. Empirical evidence from cognitive developmental research and the positive results of attempts to develop symbolic understanding in people with autism spectrum disorders (ASD) in virtual environments suggest that presenc…
How to control stock markets
1994
This paper provides a different approach to the analysis of imperfect stock markets. The model we are concerned with is described by the interaction of three institutional classes of agents (the specialist trader, the professional trader and the non-professional trader), sharing different information. The dynamical discrete-time system obtained can be changed into a second-order linear difference equation forced by the fundamental value of the specialist trader. Using typical tools of control theory, we study the behaviour of the professional trader’s fundamental value influenced by the specialist’s one. © 1994 Taylor & Francis Group, LLC.
MEMS-Based System for Structural Health Monitoring and Earthquake Observation in Sicily
2021
The implementation of systems for Structural Health Monitoring and Earthquake Observation is increasing in the last years owing to the development of new technologies which enable low-cost and small-size devices to be installed in large-scale or high-density applications. This paper introduces the implementation of monitoring systems, either for structural health assessment and earthquake observation. The applications are based in Sicily (Italy), a region characterized by a high seismic hazard and where the buildings are often old and vulnerable. The system relies on a MEMS (Micro Electro-Mechanical Systems) sensor, a 3-axial accelerometer which has been specifically selected in order to en…
Modeling software integration scenarios for telecommunications operations software vendors
2007
- Telecom operators deploy a vast number of software systems to support their operations. Vendors of these systems often integrate such software in their products in order to enable innovations, minimize the customer's integration efforts, etc. Different integration scenarios can be envisioned, and the issue of identifying more beneficial scenarios is of a great importance to the vendors. This paper focuses on analyzing different integration scenarios in the context of telecommunications operations software. For each scenario, the overall modularity of the set of software systems is evaluated, and the expected benefits of the scenario are modeled in terms of the modularity gain it provides.…
Quasi‐digital front‐ends for current measurement in integrated circuits with giant magnetoresistance technology
2014
In this study, the authors report on two different electronic interfaces for low-power integrated circuits electric current monitoring through current-to-frequency (I-f) conversion schemes. This proposal displays the intrinsic advantages of the quasi-digital systems regarding direct interfacing and self-calibrating capabilities. In addition, as current-sensing devices, they have made use of the giant magnetoresistance (GMR) technology because of its high sensitivity and compatibility with standard complementary metal oxide semiconductor processes. Single elements and Wheatstone bridges based on spin-valves and magnetic tunnel junctions have been considered. In this sense, schematic-level si…
A multi-physics integrated approach to breeding blanket modelling and design
2019
Abstract Often, for the design of a component, several kinds of analyses are needed. Even more frequently, the different fields of study, to be taken into account for the design verification, have to be examined minutely until the final results are satisfying. Furthermore, when geometry modifications are required, for instance to fulfill the component functions, the analyses cycle has to be restarted and an iterative process has to be carried out. This procedure may be time-consuming and herald of errors, in particular if it is demanded to the human activity. Therefore, it is more convenient for the scientific community to adopt a numerical tool that can combine various computational codes.…
Recognition and classification of external skin damage in citrus fruits using multispectral data and morphological features
2009
The computer vision systems currently used for the automatic inspection of citrus fruits are normally based on supervised methods that are capable of detecting defects on the surface of the fruit but are unable to discriminate between different types of defects. identifying the type of the defect affecting each fruit is very important in order to optimise the marketing profit and to be able to take measures to prevent such defects from occurring in the future. In this paper, we present a computer vision system that was developed for the recognition and classification of the most common external defects in citrus. in order to discriminate between 11 types of defects, images of the defects we…
Adaptative air traffic network: Statistical regularities in air traffic management
2016
Starting from traffic data on flights trajectories-planned and actual ones-in Europe, we build a navigation point network. We study this network which exhibits different features for different European countries. In particular, some countries uses a high number of navpoints, facilitating the planning of the flight plan by air companies at the cost of higher concentrations of traffic in few nodes. Making use of the deviations from the planned trajectories, we find that once again different countries have different control procedures with respect to traffic management. Interestingly, we find that some countries tend to make more deviations when the traffic conditions are low. Moreover, they t…