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A Straightforward Way to Chiral 7-Amino-Tetrahydroindazol-4-Ones
No full textEfficient chiral resolution of amino-tetrahydroindazoles is discusse
New Approach for High-quality Visualization of Bézier Surfaces
No full textIn this work a new approach for high-quality visualization of non-rational Bézier surfaces is proposed. There are many different approaches to solving this problem. In this work we propose a new approach for finding the values of unknown parameters, which are necessary for visualization of a Bézier surface (for example, of a bi-quadric surface). The method is based on transforming the problem of finding roots of equation to a problem of optimization
Forecasts with Single-Equation Markov-Switching Model: an Application to the Gross Domestic Product of Latvia
No full textThe paper compares one-period ahead forecasting performance of linear vector-autoregressive (VAR) models and single-equation Markov-switching (MS) models for two cases: when leading information is available and when it is not. The results show that single-equation MS models tend to perform slightly better than linear VAR models when no leading information is available. However, if reliable leading information is available, single-equation MS models tend to give somewhat less precise forecasts than linear VAR models
Modeling of Embedded Intelligent Device for Control of City Electric Transport
No full textIn this day’s the permanent increase of traffic in urban areas becomes a topical issue related to public transport routing accuracy and accurate performance of following the schedule. These problems often caused traffic jams and other unforeseen stopping reasons, but sometimes these reason of such delays is behavior of urban public transport drivers. Therefore, it is proposed to develop a control system and its operational algorithm, which helps the driver to follow the timetable with maximum precision and increased quality service for the passengers
Variant Management in Vehicle Electric and Electronic Hardware Architectures
No full textIn this paper, the issues related to a multi controller and in a meantime multi variant systems modeling such as vehicle electric and electronic architectures are described. In this study, an electric/electronic model of the vehicle’s body and powertrain domains has been developed and a set of software scripts and methods to optimize such system’s development like logical network, schematics design, wiring harness and software component organization has been implemented and evaluated
EUPOS and SLR Contribution to GOCE Mission
No full textAfter the interest of geodesists from several East European countries on successful use of SAPOS in Germany the European Position Determination System EUPOS® project has been established at 2002 under the leadership of Gerd Rosenthal, Berlin State Department of Urban Development. Currently the ground based GNSS augmentation system EUPOS® sub-networks has been developed successfully in 17 countries and the wish to join has been expressed by several other countries. EUPOS® is widely used in many practical applications. Two proposals - “EUPOS® Contribution to GOCE Mission” (Id 4307), “GOCE Observations using SLR for LEO satellites” (Id 4333), were submitted to ESA when ESA in autumn 2006 invited research people to submit proposals for GOCE mission applications. The report is presented in this article on the work which has been done in EUPOS® community and at the University
of Latvia. During last 3 years the EUPOS® subnetworks has been completed (Poland, Lithuania, Slovakia, Bulgaria, they tied to the National levelling networks, detailed system behaviour has been depicted on the bases of EUPOS®-Riga network. The development of the SLR for LEO satellites is presented. Initially it was developed for GOCE spacecraft positioning. However, SLR till now was able to observe satellites at night
The Optimization of National Development Planning System as a Precondition for Competitiveness and Sustainability of National Economy
No full textThe objective of this paper is to make conclusions regarding the development planning system in Latvia, as well as to give suggestions for the optimization of development planning system with an aim to promote sustainable development of national economy. As a result an updated and enlarged model of national development planning system is proposed. The proposed model allows to put into practice unified development planning process that connects different term and level planning documents to each other as well as national and EU funding investment planning documents. So the proposed model encourages synergy between investments of different sources, which is of particular importance in the current economical situation when resources for stimulation of economy are limited. In addition the model proposes mechanisms for stronger connection between development planning documents and political guidelines. Moreover, proposed model strengthens the linkages between development and budget planning
Brega režģa izmantošana perspektīvajās WDM sistēmās
No full textBrega režģis ir izkliedēta atstarotāja tips, kas izveidots nelielā optiskās šķiedras segmentā.
Tas atstaro noteikta garuma gaismas viļņus, bet neietekmē cita garuma gaismas viļņu
izplatību. Šis efekts tiek panākts
izveidojot periodisku izmaiņu optiskās
šķiedras laušanas koeficientā, kas veido
dielektrisku spoguli konkrētam viļņa
garumam
The Impact of Grinding Technological Regimes to the 3D Roughness Parameters of Cylindrical Surfaces
No full textIn modern manufacturing conditions of all surfaces must be seen as spatial or three-dimensional (3D) object. It can be done by definition of microtopographical surface roughness parameters which reflect to the real surface. This subsequently allows to determinate a correlation between machining technological regimes and 3D roughness parameters. Real and easy applicable methodology has to be introduced and practically applicable technological recommendations given
Al-W-B Powder Materials
No full textAl-W-B composite materials, obtained by hot pressing of separate layers of the fibres, previously covered with aluminium by thermal spraying, containing from 25% to 60% of B-W fibres, have been studied. The structure and some characteristics, in particular microhardness, of the materials and the possibility of crushing the Al-W-B material wastes into a powder were investigated. The compressibility of powders was investigated by the method of cold pressing and electrosintering and the properties of the obtained briquettes were studied. Possible fields of application of powdered Al-W-B alloy materials, such as manufacturing of grinding tools, are considered