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2189 research outputs found
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Lorentzian Operator for Angular Source Localization with Large Array, Journal of Telecommunications and Information Technology, 2015, nr 4
Get PDFSource localization problem consists of an ensemble of techniques that are used to obtain spatial information of present radiation in given medium of propagation, with a constraint of the antenna geometry and the characteristics of radiating sources. This condition gives multitude of cases to study, hence several methods were proposed in the literature. In this paper, a new algorithm for estimating the Direction of Arrival (DoA) of narrowband and far field punctual sources is introduced. By exploiting the spectrum of covariance matrix of received data, the Lorentzian function on spectral matrix to filter the eigenvalues is applied. This filtering process eliminates the eigenvalues belonging to signal subspace. Parameters of Lorentz function are adjusted using first and second statistics of eigenvalues. The algorithm requires the knowledge of minimum eigenvalue and is performing when the dimension of antenna is relatively large which is confirmed by several Monte Carlo simulations
A High Capacity Energy Efficient Approach for Traffic Transmission in Cellular Networks, Journal of Telecommunications and Information Technology, 2015, nr 3
Get PDFThe efficiency of cellular networks can be improved in various aspects such as energy consumption, network capacity and interference between neighboring cells. This paper proposes a high capacity energy efficient scheme (HCEE) for data transmission in cellular networks in a country area. In this paper, the authors obtain a new equation to characterize the minimal required output power for traffic transmission between a base station (BS) and a mobile user (MU) based on the MU distance from the BS. Also, the cells boundaries (the boundary of overlapping areas of neighboring cells) by two static and dynamic approaches are specified. This work helps for better frequency allocation to MUs and allows increasing network capacity. In this paper, the analytical modeling in order to formulate the HCEE algorithm and evaluate its performance is used. The performance evaluation results show the simplicity of the HCEE algorithm and its effect on energy consumption decline, network capacity enhancement and the interference reduction
Evaluation of the Cyber Security Provision System for Critical Infrastructure, Journal of Telecommunications and Information Technology, 2015, nr 4
Get PDFThe paper presents an assessment of the functional mechanisms that are part of the security system for the power grid control. The security system, its components, and the real time processes for the control of electricity supply were defined. In particular, SCADA protocols used in the control system and mechanisms for transferring them between the control center and actuators were identified. The paper also includes presentation of a test environment that is used for developed security mechanisms evaluation. In the last fragment of the paper, the test scenarios were formulated and the results obtained in the cyber security system were shown, which cover security probes reaction delay, forged malicious IEC 60870-5-104 traffic detection, DarkNet and HoneyPot interception of adversary actions, and dynamic firewall rules creation
Intrusion Detection in Heterogeneous Networks of Resource-Limited Things, Journal of Telecommunications and Information Technology, 2015, nr 4
Get PDFThe paper discusses the threats to networks of resource-limited things such as wireless sensors and the different mechanisms used to deal with them. A novel approach to threat detection is proposed. MOTHON is a movement-assisted threat detection system using mobility to enhance a global threat assessment and provide a separate physical secure channel to deliver collected information
Assessment of Area Energy Efficiency of LTE Macro Base Stations in Different Environments, Journal of Telecommunications and Information Technology, 2015, nr 1
Get PDFEnergy efficiency (EE) of wireless telecommunications has become a new challenge for the research community, governments and industries in order to reduce CO2 emission and operational costs. EE of base stations (BSs) in cellular net- works is a growing concern for cellular operators to not only maintain profitability, but also to reduce the overall negative impact to the environment and economic issues for wireless network operators. In this paper, a framework focuses on the Area Energy Efficiency (AEE) evaluation of LTE BSs is presented. The parameters affect on the AEE and the coverage area of LTE BS in different scenarios are investigated. AEE analysis has been done using a few key performance indicators including transmit power, bandwidth, load factor with the assumption of different scenarios (urban, suburban and rural). The simulation results show that the LTE BSs have better AEE in an urban environment for cell radius less than 750 m compare with the suburban and rural environments. Furthermore, it is obvious that there is a strong influence of traffic load, BW and transmission power on AEE of LTE network. On the other hand, AEE increases significantly as the BW size increases. Finally, it has been shown that the AEE of LTE macro BS decreases with increasing the percentage of traffic load for all scenarios
Utilization of the Software-Defined Networking Approach in a Model of a 3DTV Service, Journal of Telecommunications and Information Technology, 2015, nr 1
Get PDFIn article a new concept concerning multimedia service modeling of stereoscopic motion pictures distribution is depicted. Presented conceptual model utilizes functionality approach supported by a Software-defined Networking (SDN) architecture. The core elements composing the proposed 3D television service are stated, depicting internal arrangement of a modern 3DTV service. Moreover, investigated examples of a functional utilization of the SDN approach in a 3DTV service model realization reveal key improvements towards greater flexibility and efficiency in heterogeneous users environment
Maintenance of Lead-acid Batteries Used in Telecommunications Systems, Journal of Telecommunications and Information Technology, 2015, nr 4
Get PDFThe article presents numerous problems with standby batteries used in telecommunications systems, with a particular emphasis placed on the assessment of their real capacity. The methods used to evaluate the technical condition of batteries and to measure their real capacity are presented. Also, the a new test device which measures the actual battery capacity is presented. The said measurement is based on the discharge test method and is performed with the use of a new TBA-A automated test unit. The article is targeted for electronic designers, managers and telecommunications hardware maintenance personnel, as well as for other telecommunications systems experts
A Survey on Wireless Network Applications in Automated Public Utilities Control and Management, Journal of Telecommunications and Information Technology, 2015, nr 3
Get PDFPublic utilities such as water, electricity and gas are essential services that play a vital role in economic and social development. Automation of public utility services addresses the huge losses faced by the utility services today, due to non-accounting of distributed utility resources. Automation improves government revenues. The different type of architectures are proposed and designed for automated metering, control and management of public utilities like water, gas, and electricity for effective management and control of resources. The various network topologies, hardware and software architectures to automation and management of public utilities are proposed by researchers. In this paper, the different technologies proposed by various researchers across the globe are surveyed and list of issues and challenges for automated meter reading and control of public utilities is identified
Performance Comparison of Four New ARIMA-ANN Prediction Models on Internet Traffic Data, Journal of Telecommunications and Information Technology, 2015, nr 1
Get PDFPrediction of Internet traffic time series data (TSD) is a challenging research problem, owing to the complicated nature of TSD. In literature, many hybrids of auto-regressive integrated moving average (ARIMA) and artificial neural networks (ANN) models are devised for the TSD prediction. These hybrid models consider such TSD as a combination of linear and non-linear components, apply combination of ARIMA and ANN in some manner, to obtain the predictions. Out of the many available hybrid ARIMA-ANN models, this paper investigates as to which of them suits better for Internet traffic data. This suitability of hybrid ARIMA-ANN models is studied for both one-step ahead and multi-step ahead prediction cases. For the purpose of the study, Internet traffic data is sampled at every 30 and 60 minutes. Model performances are evaluated using the mean absolute error and mean square error measurement. For one-step ahead prediction, with a forecast horizon of 10 points and for three-step prediction, with a forecast horizon of 12 points, the moving average filter based hybrid ARIMA-ANN model gave better forecast accuracy than the other compared models
Intrusion Detection in Software De ned Networks with Self-organized Maps, Journal of Telecommunications and Information Technology, 2015, nr 4
Get PDFThe Software Defined Network (SDN) architecture provides new opportunities to implement security mechanisms in terms of unauthorized activities detection. At the same time, there are certain risks associated with this technology. The presented approach covers a conception of the measurement method, virtual testbed and classification mechanism for SDNs. The paper presents a measurement method which allows collecting network traffic flow parameters, generated by a virtual SDN environment. The collected dataset can be used in machine learning methods to detect unauthorized activities