Archivio della ricerca di Triestehttps://arts.units.itIl sistema di repository digitale IRIS acquisisce, archivia, indicizza, conserva e rende accessibili prodotti digitali della ricerca.Thu, 26 Nov 2020 07:43:33 GMT2020-11-26T07:43:33Z10471An algorithm for linearly constrained piecewise lexicographic programminghttp://hdl.handle.net/11368/2555648Titolo: An algorithm for linearly constrained piecewise lexicographic programming
Mon, 01 Jan 2001 00:00:00 GMThttp://hdl.handle.net/11368/25556482001-01-01T00:00:00ZEvaluation of spaces for the separation of signals due to multiple PD sourceshttp://hdl.handle.net/11368/2841255Titolo: Evaluation of spaces for the separation of signals due to multiple PD sources
Abstract: Results of investigations having the purpose to evaluate different spaces suitable for PD signal separation, are presented in this paper. Signals recorded during tests performed on real objects where the number of PD sources were a-priori known, have been projected in different spaces and the same procedure based on OPTICS clustering algorithm, has been used to separate groups of signals due to the different sources. The separation efficiency has been first evaluated in terms of correct separation then, the density and the distance between the different groups have been used to select the most effective separation space. The criteria here considered can constitute a useful tool to evaluate the efficiency of actual and future separation methods.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/11368/28412552015-01-01T00:00:00ZInfluence of DC-DC load converter control bandwidth on small-signal voltage stability in MVDC power systemshttp://hdl.handle.net/11368/2892714Titolo: Influence of DC-DC load converter control bandwidth on small-signal voltage stability in MVDC power systems
Abstract: Voltage stability is a key problem in Medium Voltage DC (MVDC) power systems. A model of a power system able to give proper stability information as a function of load converters control bandwidth is of fundamental importance, particularly if simple and of simple application. In this paper, a notional system composed by two cascaded DC-DC buck converters is considered.
It is modeled at small-signals around its equilibrium point first using a complete model and then it is simplified in order to obtain the well-known Constant Power Load (CPL) model.
Furthermore, an intermediate (reduced-order) model between the complete one and the CPL is proposed, which is able to show proper conditions on the load converter bandwidth to assure stability. Small-signals numerical simulations are used to validate the proposed complete and reduced-order models comparing results.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/11368/28927142016-01-01T00:00:00ZPolyhedral Elements: a New Approach for Capturing All the Equilibrium Points of Piecewise-Linear Circuitshttp://hdl.handle.net/11368/1699325Titolo: Polyhedral Elements: a New Approach for Capturing All the Equilibrium Points of Piecewise-Linear Circuits
Abstract: An entirely new algorithm to find all the equilibrium points of
piecewise-linear (PWL) circuits is presented. To this aim, the new class
of the so-called polyhedral circuits, associated to the PWL ones, are defined
by replacing the PWL elements with the polyhedral elements. The algorithm is
structured as a genealogical tree, whose nodes represent specific polyhedral
circuits. All the equilibrium points of the original PWL circuit can be
captured by the analysis of these nodes. This analysis requires the solution
of the Phase I of Linear Programming (LP) problems, one problem for each node.
An example shows the capabilities of this algorithm.
Fri, 01 Jan 1993 00:00:00 GMThttp://hdl.handle.net/11368/16993251993-01-01T00:00:00ZCapturing all Branches of Any One-Port Characteristic in Piecewise-Linear Resistive Circuitshttp://hdl.handle.net/11368/1699326Titolo: Capturing all Branches of Any One-Port Characteristic in Piecewise-Linear Resistive Circuits
Abstract: An algorithm to capture all the unicursal branches of any one-port
characteristic in piecewise-linear (PWL) resistive circuits is described. The
heart of this algorithm is based on the so-called polyhedral augmented circuits:
they are constructed by replacing each PWL element by a suitable polyhedral
element and by connecting a norator to the one-port. The structure of the algorithm
is based on a genealogical tree, whose nodes represent specific polyhedral augmented
circuits. All branches of the PWL one-port characteristic can be captured by checking
the solution domains of these circuits. from the numerical point of view,
the investigation of the nodes requires the execution of related Linear Programming
(LP) problems, one for each node. However, the similar structure of their tableaux
allows the reduction of the overall CPU time.
Mon, 01 Jan 1996 00:00:00 GMThttp://hdl.handle.net/11368/16993261996-01-01T00:00:00ZFinding All Solutions of Nonlinear Resistive Circuits by Exploring Both Polyhedral and Rectangular Circuitshttp://hdl.handle.net/11368/1699327Titolo: Finding All Solutions of Nonlinear Resistive Circuits by Exploring Both Polyhedral and Rectangular Circuits
Abstract: A new fast method to find all the DC solutions of piecewise-linear (PWL)
resistive circuits is presented. The structure of the algorithm is based on
the exploration of a binary tree: each node represents a specific PWLsub
circuit, derived from the original PWL circuit by truncating the original
PWL characteristics. The terminal nodes of the tree represent the linear
circuits related to single linear regions. The natural exponential growth
of the tree is controlled by two different criteria. They are based on
the investigation of the convex solution domains of the so-called polyhedral
circuits or, alternatively, of the so-called rectangular circuits. The first
criterion is more efficient but more CPU-time consuming than the second one.
An appropriate combination of both allows the realization of an overall
algorithm faster than those based on a unique criterion.
Wed, 01 Jan 1997 00:00:00 GMThttp://hdl.handle.net/11368/16993271997-01-01T00:00:00ZA Fast and Simple Method to Find All Equilibrium Points of Dynamic 1D Arrayshttp://hdl.handle.net/11368/1699329Titolo: A Fast and Simple Method to Find All Equilibrium Points of Dynamic 1D Arrays
Abstract: A very fast and simple algorithm for finding all equilibrium points of
dynamic 1-dimensional (1D) arrays, constituted by resistively-coupled dynamic
piecewise-linear cells (for example, oscillators) is presented. This algorithm
is based on the recursive construction of a uni-path $v$-$i$ characteristic
derived from the associated resistive array, obtained by opening the capacitors
and shortening the inductors within dynamic cells. Some examples show the
efficiency of the algorithm. About 30,000 equilibrium points of a
100-cell array are determined within a few seconds with a common PC.
Mon, 01 Jan 2001 00:00:00 GMThttp://hdl.handle.net/11368/16993292001-01-01T00:00:00ZAn Algorithm for Linearly Constrained Piecewise Lexicographic Programming Problemshttp://hdl.handle.net/11368/1699328Titolo: An Algorithm for Linearly Constrained Piecewise Lexicographic Programming Problems
Abstract: The Linear Piecewise Lexicographic Programming (LPWLGP) problem is a
mathematical programming model with linear constraints and several piecewise
linear objective functions, arranged in a lexicographic hierarchy.
Lexicographic spaces are introduced, and the differential properties of
functions taking values in them are discussed. Necessary and sufficient
optimality conditions for the LPWLGP problem are derived, and an algorithm
based on them is formulated.
Mon, 01 Jan 2001 00:00:00 GMThttp://hdl.handle.net/11368/16993282001-01-01T00:00:00ZVoltage Sag Analysis through Wavelet Transformhttp://hdl.handle.net/11368/2296229Titolo: Voltage Sag Analysis through Wavelet Transform
Thu, 01 Jan 1998 00:00:00 GMThttp://hdl.handle.net/11368/22962291998-01-01T00:00:00ZClassification and Separation of Partial Discharge Signals by Means of their Auto-Correlation Function Evaluationhttp://hdl.handle.net/11368/2292491Titolo: Classification and Separation of Partial Discharge Signals by Means of their Auto-Correlation Function Evaluation
Abstract: This paper describes a K-Means Clustering classification algorithm for the separation
of Partial Discharge (PD) signals and pulsating noise due to multiple sources occurring
in practical objects. It is based on the comparison of the Auto-Correlation Function
(ACF) of the recorded signals assuming that the same source can generate signals
having similar ACF while ACF differ when signals with different shapes are compared.
The ACF has been selected for its capability of well summarize both time- and
frequency-dependent features of the signals. A correlation index that presents the best
compromise between strong and weak discrimination among pulses, has been selected
out of different distance measurements. The final result of the algorithm is a set of
classes containing signals having similar shape which can be processed successively for
signal source identification. Meaningful applications of the proposed algorithm are also
reported. Improvements in separation effectiveness can enhance the clearness of the
PD patterns and, consequently, the quality of the defect identification.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/11368/22924912009-01-01T00:00:00Z