Search results for "complexity"
showing 10 items of 1094 documents
Practical Implementation of a Synchronous PWM Strategy for Low Switching Frequency FOC of im Drives with ATSAM3X8E Microcontroller
2021
This paper presents a practical implementation of synchronous PWM modulation algorithm for an induction motor field oriented control powered by a DC/AC inverter and implemented on a low-cost microcontroller, the ATSAM3X8E. In particular, a simple algorithm, capable to calculate automatically an optimized set of frequency modulation indexes will be presented. Hysteresis bands are also introduced in the algorithm in order to avoid multiple changeovers during modulation index transitions. Experimental tests and their results will be shown and discussed, highlighting the benefits of the present algorithm, such as reduction of current harmonic content, reduction of current ripple and, consequent…
Market Polarization due to Difference in Interface Implementation Efforts
2009
Another factor potentially affecting the evolution of the OSS/BSS software market is the high complexity of software interfaces. The software provided to a customer – a CSP – needs to be integrated with a number of heterogeneous subsystems deployed by the customer. If the number of integration interfaces is high, a vast amount of special knowledge is needed in the vendor organization. High integration efforts also take up the time of the compentent employees of the vendor organization, thereby reducing the number of customers which it is capable of serving. As a result, only few large vendors can compete in such market, and, due to a lack of competition, the evolution towards a horizontaliz…
Chromatic sums for colorings avoiding monochromatic subgraphs
2015
Abstract Given graphs G and H, a vertex coloring c : V ( G ) → N is an H-free coloring of G if no color class contains a subgraph isomorphic to H. The H-free chromatic number of G, χ ( H , G ) , is the minimum number of colors in an H-free coloring of G. The H-free chromatic sum of G , Σ ( H , G ) , is the minimum value achieved by summing the vertex colors of each H-free coloring of G. We provide a general bound for Σ ( H , G ) , discuss the computational complexity of finding this parameter for different choices of H, and prove an exact formulas for some graphs G. For every integer k and for every graph H, we construct families of graphs, G k with the property that k more colors than χ ( …
Programmable VLSI cubic-like function implementation
2006
An analogue VLSI implementation of a cubic-like function is presented, whose design is focused to reduce the circuit complexity. Simulations show that the V–I characteristic of the circuit resembles a cubic function, which can be easily adjusted by changing the bias parameters.
Feedback vibration control of a base-isolated building with delayed measurements using h<inf>&#x221E;</inf> techniques
2010
In this paper we address the problem of vibration reduction of buildings with delayed measurements, where the delays are time-varying and bounded. We focus on a convex optimization approach to the problem of state-feedback H ∞ control design. An appropriate Lyapunov-Krasovskii functional and some free weighting matrices are used to establish some delay-range-dependent sufficient conditions for the design of desired controllers in terms of linear matrix inequalities (LMIs). The controller, which guarantees asymptotic stability and an H ∞ performance, simultaneously, for the closed-loop system of the structure, is then developed. The performance of the controller is evaluated through the simu…
Greenhouse Gas Emission Reduction Due to Improvement of Biodegradable Waste Management System
2014
Abstract To reduce emissions of greenhouse gas (GHG) from landfills, the European Union (EU) Landfill Directive 1999/31/EC requires that there be a progressive decrease in the municipal biodegradable waste disposal. The main problem of waste management (WM) in Latvia is its heavy dependence on the waste disposal at landfills. The poorly developed system for the sorted municipal waste collection and the promotion of landfilling as a major treatment option led to the disposal of 84% of the total collected municipal waste in 2012, with a high biodegradable fraction. In Latvia, the volume of emissions due to activities of the WM branch was 5.23% (632.6 CO2 eq.) of the total GHG emissions produc…
Temporal incoherent solitons supported by a defocusing nonlinearity with anomalous dispersion
2012
http://pra.aps.org/; International audience; We study temporal incoherent solitons in noninstantaneous response nonlinear media. Contrarily to the usual temporal soliton, which is known to require a focusing nonlinearity with anomalous dispersion, we show that a highly noninstantaneous nonlinear response leads to incoherent soliton structures which require the inverted situation: In the focusing regime (and anomalous dispersion) the incoherent wave packet experiences an unlimited spreading, whereas in the defocusing regime (still with anomalous dispersion) the incoherent wave packet exhibits a self-trapping. These counterintuitive results are explained in detail by a long-range Vlasov formu…
Evaluation of the use of wavefront encoding to reduce depth-induced aberration in structured-illumination microscopy
2018
Three-dimensional imaging is affected by depth-induced spherical aberration (SA) when imaging deep into an optically thick sample. In this work, we evaluate the impact of SA on the performance of incoherent grating-projection structured illumination microscopy (SIM). In particular, we analyze the reduction of the contrast in the structured pattern and compare the reconstructed SIM images for different amounts of SA. In order to mitigate the impact of SA, we implement and evaluate in SIM a wavefront encoded imaging system using a square cubic (SQUBIC) phase mask, an approach shown previously to be successful in conventional microscopy.
Variances as order parameter and complexity measure for random Boolean networks
2005
Several order parameters have been considered to predict and characterize the transition between ordered and disordered phases in random Boolean networks, such as the Hamming distance between replicas or the stable core, which have been successfully used. In this work, we propose a natural and clear new order parameter: the temporal variance. We compute its value analytically and compare it with the results of numerical experiments. Finally, we propose a complexity measure based on the compromise between temporal and spatial variances. This new order parameter and its related complexity measure can be easily applied to other complex systems.
The nature of security and risk in complex socio-technical systems : a partial application of Critical Systems Heuristics (CSH) to Finnish Security S…
2011
Tämä tutkimus selventää suhteita turvallisuuden, riskien sekä kompleksisten sosio-teknisten järjestelmien välillä. Käsittely tapahtuu pääosin yhteiskunnallisella tasolla, mutta eri järjestelmiä ja niiden yleisiä sekä teoreettisia perusrakenteita tarkastellaan kokonaisuuden ymmärtämiseksi paremmin. Samalla pyritään parantamaan käsitystä niistä monista yhteisvaikutuksista joita eri järjestelmillä on toisiinsa ja miten ne vaikuttavat turvallisuuteen. Turvallisuus on tunnistettu olevan suhteellista ja käyttäytyvät eri tavalla todellisissa avoimissa järjestelmissä ja avoimessa järjestelmien ympäristössä, verrattuna yksinkertaisiin järjestelmiin. Teknologia on alati läsnä nykyaikaisissa kehittyne…