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Akciju indeksu viļņu (Wavelet) analīze
No full textŠis pētījums ir veltīts kapitāla tirgus analīzei, izmantojot viļņu (veivlet) pārveidojumu metodi. Viļņu pārveidojumi ir plaši izmantojamā metode signālu apstrādē un attēlu kompresijā. Tāpāt viļņu pārveidojumi ir ideāli piemērojami nestacionāru signālu analīzei, sekojoši arī finanšu laikrindu analīzei. Par eksperimenta objektiem kļuvuši deviņi pasaules akciju indeksi: Dow Jones Industrial Average, AEX, CAC40, DAX30, IBEX, FTSE100, Nikkei225, SMI, STI. Dow Jones Industrial Average indekss aplūkots par periodu: no 01/10/1928 līdz 03/10/2011, citi minētie indeksi tika analizēti šādā laikposmā: 05/07/1993 līdz 03/10/2011. Akciju indeksi ir dekompozēti uz trenda un trokšņa komponentiem ar veivlet filtrāciju. Komponentes ir analizētas ar nepārtrauktiem viļņu pārveidojumiem atsevišķi. Pētījumā ir parādīta saikne starp divām komponentēm. Pētījuma ir izklāstīta metode, kas ļauj identificēt finanšu tirgus nestabilitāti
Baltic National Transmission Network Development Tendency
No full textThe article discusses the development of Baltic transmission networks, related to the program of the European Union (EU) to improve the security of energy supply, competitiveness and improve the development. Consider infrastructure projects to meet the needs of electricity in the EU. The highlight issues are plan of Baltic energy markets merging and Latvian energy market development tendency
Analysis and Improvement of Nocturnal Enuresis Alarm System
No full textBedwetting (Nocturnal Enuresis) is a common problem throughout the world, it has a very high prevalence in the preschool population and the prevalence slowly falls during childhood. Several therapies exist to solve this problem, one of them is enuresis alarm, which is a primary and an effective nocturnal enuresis treatment method for children. In the paper different alarm systems were summarized: pad-and-bell alarms, wearable wired alarms and wearable wireless alarms, analyzing its advantages and drawbacks Operation and construction as well as attachment technology and placement in the garment of alarm units and sensors have been explored. This study describes issues related to enuresis alarm systems from the comfort and safety point of view, as well as recommendations for improvement of sensor and alarm unit design
Screen Printed Sensor for Enuresis Alarm System
No full textScreen printed sensor traces for nocturnal enuresis alarm system were developed.
Choice of the Optimal Power of Distributed Lighting System Unit
No full textThe article looks on the considerations about the
choice of optimal power for distributed lighting system unit. Such
parameters as mounting height, distance between light sources
and spatial light distribution of light source are discussed in this
paper. These parameters are related with uniformity calculations
from EN 12464-1:2002 standard.
The second part of this article is related with the assessment of
the unit of lighting system by the evaluation of relative costs. The
conclusions about the best evaluation method are given at the end
of this article
The Dynamics of Electricity Market Liberalization of the Baltic States
No full textThe main problem of development and improvement of Baltic States electrical market is considered. In the paper is noted, the influence of various factors on the pricing in the region and particularly the electricity price level in Scandinavia. There is indicated on the expediency of single market creation in the region and expansion of the exchange stock Nord Pool work on its territory. The concrete measures are generalized, the realization of which will contribute to the further development of market in the Baltic region and it will be major step on the road to the creation the uniform market for continental Europe
Tapped-Inductor Converter for Dimmable Light-Emitting Diode Driver
No full textThe increasing popularity of light-emitting diodes (LEDs) encourages researchers to search for new approaches to control brightness of LED illumination. Recently articles have been published on the use of tapped-inductor converters as LED drivers, where high step-down ratio applications were discussed. This article focuses on the estimation of controllability parameters of such a kind of converters operating in continuous current mode. Numerical calculations and experimental results are presented in the paper. Also the conclusion about a better topology and configuration with described comparison criteria is given at the end of the article
Electric Machines with Non-Radially Mounted Rectangular Permanent Magnets
No full textThe authors analyze the advantages and disadvantages of brushless synchronous electric machines with radially and non-radially mounted rectangular permanent magnets. The results show that the proposed non-radial mounting of permanent magnets considered in the paper, in several cases (e.g. multi-pole brushless generators with tooth windings of the armature) allows achievement of the following advantages: better technology of manufacturing the electric machine owing to simple packing of the stator winding in the stator open slots, which also increases the copper slot fill-factor; reduction in the mass-and-size of permanent magnets at least twice; significantly lower cost of the electric machine; and, finally, its greater specific power
Testing Thermal Rating Methods for the Overhead High Voltage Line
No full textDue to the limited capacity of the existing transmission lines, new advanced technologies are implemented towards the Smart Grid. Here the interest is in the overhead line thermal monitoring systems, which are generally designed based on the existing methodologies by using the limiting conditions for the determination of the ampacity of power lines. Thus, the evaluation of commonly used thermal rating methods, which include estimation of the conductor temperature as well as the conductor sag, is quite a topical objective, which should by all means be discussed. The paper presents a comparative assessment of the measured and calculated steady-state conductor temperatures as well as line sagging, on the basis of which the testing of thermal rating methods was conducted. The experimental measurements were done using special monitoring equipment in weather conditions under cases “A” and “B” based on the existing lines of the Latvian power network. The obtained results are reviewed in this paper
