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Comparative Analysis of Statistical and Information Measures for Benchmark Fitness Landscapes
No full textVarious techniques of fitness landscape analysis for
the determination of optimisation problem hardness for
evolutionary algorithms are proposed in the literature.
However, a few implementations of these techniques and their
application in practice are described nowadays. In this paper
fitness landscapes of benchmark fitness functions are analysed.
Statistical and information measures of fitness landscapes are
briefly described. Measures of both types are calculated and
interpreted for this benchmark landscapes. Detailed
calculations of performed experiments are provided and
analysed in this paper. The obtained results will allow
estimating hardness of different potential optimisation
problems for application of the evolutionary algorithms.
Conclusions about the influence of conditions and parameters
of the fitness landscape analysis techniques on the results that
could be achieved also are made
Līdzsvarota reģionālā attīstība Latvijā
No full textRakstā dots ieskats Latvijas reģionālās attīstības tendencēs 1930-jos gados, lai novērtētu Latvijas vēsturisko pieredzi. Jau tajā laikā iezīmējās dažu reģionu konkurences priekšrocības un specializācija. Latvijā sociāli ekonomiskās atšķirības starp reģioniem ir pastāvējušas gan pirmās brīvvalsts laikā, gan turpina pastāvēt arī mūsdienās. Ir mainījušies akcenti un galvenie saimnieciskās darbības virzieni, bet pamatā ģeogrāfiskās priekšrocības ir un paliek nemainīgas. Viena no mūsdienu aktuālākajām problēmām ir nevis reģionālo atšķirību izlīdzināšana, bet gan reģionu padarīšana par pievilcīgu dzīves un darba vietu
Stability in Impulsive Systems with Markov Perturbations in Averaging Scheme. I. Averaging Principle for Impulsive Markov Systems
No full textThe Bogoliubov–Mitropolsky small parameter method is used to study the behavior of stochastic
differential systems in the analysis of the corresponding properties of solutions of averaged systems
Kombinēta koka pārseguma racionālu ģeometrisko parametru noteikšana
No full textKombinēta koka pārseguma racionālu ģeometrisko parametru noteikšan
Simulation of Trolleybus Traction Induction Drive with Supercapacitor Energy Storage System
No full textRakstā apskatītas Škoda 24Tr tipa trolejbusa rekuperētās enerģijas saglabāšanas iespējas, uzstādot borta superkondensatoru enerģijas uzkrājēju ar automātisku pārslēgšanos uz autonomās vilces režīmu. Piedāvāta enerģijas uzkrājēja vadības sistēma ar konstantu DC kopnes spriegumu superkondensatora uzlādes režīmā un superkondensatora strāvu, proporcionālu vilces pārveidotāja strāvai superkondensatora izlādes režīmā. Izpētīta trolejbusa asinhronās piedziņas un enerģijas uzkrājēja vadības sistēmas stabilitāte gan īslaicīgos, gan ilgstošos tīkla sprieguma pazušanas režīmos. Sistēmas modelēšana veikta ar Matlab/Simulink asinhronās vilces piedziņas modeļa un PSIM enerģijas uzkrājēja modeļa apvienošanu vienotā sistēmā
Research and Development of Effective Managing Algorithms in Admission Control Systems for Telecommunication Networks
No full textŠī darba pamatuzdevums – izstrādāt vadības algoritmus datu plūsmu piekļuves sistēmai pie
komunikāciju resursiem, vienlaicīgi nodrošinot uzdoto apkalpošanas kvalitāti.
Tika pētīti sekojošie algoritmi: piekļuves vadības un plūsmu dispečerizācijas algoritmi,
resursu pārdales algoritmi, sistēmas noslodzes maksimizācijas algoritmi ar apkalpošanas kvalitātes garantiju nodrošināšanu.
Pētījumu rezultātā tika izstrādās rekomendācijas piekļuves vadības sistēmas funkcionēšanas optimizācijai. Izstrādāto rekomendāciju pārbaudei tika izmantota OPNET
modelēšanas sistēma
A Mathematical Model for the Temperature Field of a New Type Solar Collector
No full textThe temperature field problem described in the paper is analytically solved for the absorber of a new type solar collector. The absorber consists of two plates, one of them being flat and placed on top of the other plate made with square profile. The temperature field is calculated for four areas using the Laplace equation under stationary conditions. For each area the boundary conditions are written and the Laplace equation solved. The resultant temperature fields are found for each area separately
Computer-Based Modelling of Identification Algorithms
No full textAbstract – Traditional identification algorithms that are based on model parameter adjustment often have methodical errors. These errors prevent a practical application of identification results in automated computer control and diagnosis of technical objects. Methodical errors have a hidden character and, consequently, software stops working. The obtained numerical data have abstract character and no reasonable physical interpretation. There are not any mathematical methods that could be applied to decode them. Such conclusion follows from the proofs obtained in an analytical form in this paper. Until recently, they could not be obtained using traditional computing methods. It required finding, in an analytical form, the solution of systems of difference equations on the basis of which identification models are formed. With the help of the method described in this paper, this problem has been solved. It is proved that introducing into the model any additional operators, as it is done in stochastic models [17], [18], is undesirable. Also it is proved that it is necessary to carry out full cycle of identification, instead of stopping it at the stage of estimating the discrepancy of the system of difference equations. The process should end with checking the reliability of estimations of parameters of analog object’s transfer function
Jauns diacetonglikozes 3-spirooksazolidinona un tā atvasinājumu sintēzes paņēmiens
No full textaprakstīts jauns veids no glikozes atvasinātu spirooksazolidinonu sintēze
Evaluation and Improvement of Web Information System Accessibility with Markup Language Possibilities
No full textMarkup languages are used to describe the content published in the World Wide Web. Aim of this article is to analyze hypertext markup language versions and identify possibilities of improvement accessibility for the web information systems with markup language elements appropriate application. Analysis of the document structure is performed. Document structure and text description elements are selected. Selected elements are practically evaluated with screen readers. From the evaluation results, it can be seen that markup language possibilities for accessibility improvement can be significant