2009, VOLUME 10 #3. "TRANSPORT AND TELECOMMUNICATION". ЖУРНАЛ ИЗДАТЕЛЬСТВА TSI, ISSN 1407-6160, ISSN 1407-6179
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Yury A. Krasnitsky
Transport and Telecommunication Institute
Lomonosov str., 1, Riga, LV-1019, Latvia
Ph.: +371 67100608. Fax: +371 67100660.
It is proposed the method to estimate an inherent structure of transient pulses based on empirical mode decomposition (EMD). It permits to expand any signals (including non-stationary and non-linear ones) into a little amount of quasi-harmonics named intrinsic mode functions (IMFs). The IMFs concept leads to an analogy with spectrum calculated by Fourier transformation (FT). In this work it is proposed to apply EMD for expanding logarithm of that spectrum into new set of IMFs. Instantaneous frequencies analysis of the latter creates a certain “quasicepstrum” which can serve as an estimation of inherent structure of the learned signal. The Matlab codes are worked out to illustrate the proposed method and to compare it with FT. The results are presented for processing natural electromagnetic (EM) pulses.
Keywords: non-stationary signal, logarithmic spectrum, cepstrum, empirical mode decomposition
Boris Tsilker1, Vladimir Pyatkov2
Service area coverage problem has existed and still remains a fundamental issue in construction of wireless networks. Most of known investigations, concerned with optimal (in sense of ensuring of necessary coverage level at every point in service area) deployment of network nodes, i.e., with optimal network topology, study the problem on the assumption that wireless network service area is free from obstacles, impeding normal propagation of information signals [1-3]. As a result, suggested network topologies become ineffective at presence of obstacles within serviced area. More realistic solution presumes taking into account of obstacles within the serviced area. Possible approaches for placement of wireless network nodes on condition that service area contains obstacles are discussed at present work. Problem is examined from two points of view: as a probabilistic task, as well as a task of computational geometry. The investigation is resulted in some conceptual considerations and practical algorithms for this problem solving.
Keywords: wireless networks, coverage, obstacle, service area, Voronoi diagram
Alexander Krivchenkov, Sergei Lavrov
We consider the on-board power system in terms of monitoring insulation resistance of consumers who are connected and disconnected during operation. Such a system power supply may be provided by an equivalent scheme, which allows you to calculate the currents and voltages at any instant of time. This equivalent circuit is used as a basis of model for statistical research of the system and of the method for continuous monitoring of the insulation resistance of consumer power. A statistical study showed sufficient accuracy of the proposed method of measuring. The estimates of the parameters of the system and of the proposed control method are made.
Keywords: on-board power system, model, insulation resistance
Agassi Melikov, Mehriban Fattakhova
In this paper the model of integrated voice/data cellular wireless networks (CWN) is investigated. The refined approximate algorithms to calculate the desired Quality of Service (QoS) metrics in isolated cell of such networks under multi-parametric call admission control (CAC) strategy are developed. The given strategy is based on cut-off scheme. Results of numerical experiments are given.
Keywords: cellular networks, call admission control, quality of service, calculation algorithm
Transport and Telecommunication Institute
Lomonosova str., 1, Riga, LV-1019, Latvia
A rule of optimum signal sampling is set as superposition of continuous stationary random fluctuations with non-finite spectrum, providing selection of uniform signal samples containing the most valuable information about the signal.
Keywords: aggregate signal, non-finite spectrum, optimal sampling
Gabriel Nowacki1, Izabella Mitraszewska2, Tomasz Kamiński3
Motor Transport Institute
Management and Transport Telematics Centre
Jagiellońska 80, 03–301 Warsaw, Poland
Phone +48 228113231 ex. 134
E-mail: 1 email@example.com
The paper refers to some problems of the EETS interoperability. In Europe, different road charging systems are being operated by professional companies making use of state-of-the-art technologies. Interoperability of road charging solutions is a long-term objective of the EC and the directive 2004/52/EC. According to directive EETS should use one or more of the following technologies: satellite positioning, mobile communications using the GSM-GPRS standard and 5, 8 GHz microwave. Based on Directive 2004/52, the European Commission was seeking to establish an open framework for road charging (taxing or tolling) systems in Europe, which enables interoperability at the technical, procedural and contractual level and the EC initialised a process of projects and expert groups which would contribute to the formulation of, and consensus on, a definition of the European Electronic Tolling Service (EETS). In EETS architecture two charging principles for a tolled infrastructure are supported: DSRC-based tolled infrastructure or GNSS enabled tolled infrastructure. Architecture defines the technical detail of the interfaces for road charging systems that are interoperable in a manner that they correspond to the interfaces between the business entities that together operate the service: the Toll Charger, the Toll Service Provider and the Service User.
Keywords: EETS, interoperability, toll charger, toll service provider, service user, interfaces