[show abstract][hide abstract] ABSTRACT: This paper presents two methods for determining the noise power (mainly caused by crosstalk) in Digital Subscriber Line (DSL) networks. A fuzzy system approach is compared to a linear regression approach. Both are applied to a real world DSL network where a variable noise power is injected. Knowledge Discovery in Database (KDD) is used to organize the data selection, while linear regression and Fuzzy algorithms are compared through data mining process. Results show that the use of techniques such as Fuzzy and linear regression are an effective solution for the real-time estimation of crosstalk in DSL systems. The proposed scheme can be adapted to other types of noise, thus extending its application to DSL systems.
[show abstract][hide abstract] ABSTRACT: Electromagnetic waves are affected by different phenomena along their propagation. In addition to signal scattering, the polarization of the transmitting and receiving antennas should be considered because the effect of different polarizations causes loss of reception. Such polarization affects the parameters of quality of service (QoS). In this paper, a methodology for wireless local network (WLAN) project is presented. It is based on measurements of received power and QoS parameters. The obtained results were evaluated using a network qualifier which will be used to establish the access point coverage area.
[show abstract][hide abstract] ABSTRACT: The search for improvement in the process of diffusion of information has led to many advances in access technologies. In initiatives for digital/social inclusion, this improvement is of utter importance, particularly in scenarios where the infrastructure becomes a barrier in communication. An alternative to improve communication and thus providing quality of service is to adjust the use of resources/bandwi dth required by the applications. This paper presents an application-sche duling algorithm, based on fuzzy logic, to optimize the use of and guarantee QoS for existing applications. Simulations were made from a built testbed for xDSL technology; results showed that the proposed scheduler is able to optimize the channel, guaranteeing minimum levels of QoS based on the particular needs and characteristics of each application.
Proceedings of the 12th IFIP/IEEE International Symposium on Integrated Network Management, IM 2011, Dublin, Ireland, 23-27 May 2011; 01/2011
[show abstract][hide abstract] ABSTRACT: This paper presents an estimation of Quality of Experience (QoE) metrics based on Quality of Service (QoS) metrics in WiMAX networks. Applications used to generate such estimations were EvalVid and Network Simulator 2 (NS-2). The QoE was estimated by employing a Multilayer Artificial Neural Network by means of the WEKA tool. The results show a very efficient estimation of metrics of QoE parameters with respect to QoS parameters.
[show abstract][hide abstract] ABSTRACT: This paper presents a propagation model for prediction of path loss and performance parameters (throughput and frame loss) on OFDM-based networks. For this study, measurements on a 5.8 GHz Wimax network were carried out. The proposed model parameters have been adjusted by LS (Least Squares) optimization, using measured data as reference. The results show that the proposed model has a good agreement with the measurements. Futures works can consider an adjustment for a set of frequencies. For this purpose, extensive measurements campaigns will be carried out.
[show abstract][hide abstract] ABSTRACT: DSL (Digital Subscriber Line) technology enables a universal broadband access at a reduced cost and time for implementation required for others access networks since it is considered a large capillarity broadband network, using a combination of the existing telephony infrastructure and digital subscriber line transmission technologies, which are widely available to end users in most developed countries. The environment and the flow to be
[show abstract][hide abstract] ABSTRACT: This paper presented a strategy to extend the potentialities of BN, with respect to their inference process. It also showed, as a motivation for this strategy, assistance to the demands of the electric sector. Among the main contributions of the proposed strategy, we can point out the following. The extension of the power of interpretability of the BN through the discovery of the optimal combination of values, represents the possibility of quantifying the causal relationships among the socio-economic and electricity consumption variables, and allows to achieve a given goal or a key aspect; The interest of those involved in this Project, in applying the functionalities of the model in many other scenarios, not only relative to the power consumption, but also for government actions (e.g. discovery of the variables, and their values, that would maximize the generation of employment and income), has encouraged the use of the proposed model. This interest can further seen by the current use of the model in other Brazilian states, whose
[show abstract][hide abstract] ABSTRACT: In this chapter a novel WLAN planning and performance evaluation strategy with computational intelligence approach, i.e., bayesian networks was presented. The measuring technique was used through an empirical study concerning the behavior of the QoS parameters of an VoIP application in 802.11g network. This study was performed in two different indoors and outdoors environments, characterizing two types of scenarios. This was done to establish the correlation between the behavior of the QoS parameters and the distance. The main contribution of the Bayesian strategy is the use of computational intelligence to differentiate the two environments and to validate the robustness of the methodology proposed here. Another contribution is about the installation of new hot spots at digital cities, that must be installed at State of Pará. In addition, due to the large application of wireless LAN, this strategy can be applied in real engineering design. This methodology will aid the decision makers where to locate the access point to better attend the public ofﬁces, according on the applications that must be used. It is important to mention that Bayesian network offers an
[show abstract][hide abstract] ABSTRACT: Summary This paper evaluates the performance of three algorithms for allocating wavelength optical networks WDM (Wavelength Division Multiplexing) and they are: first-fit, least-used e most-used. The objective of the experiment was to simulate the performance of allocation algorithms on relevant aspects: throughput and blocking probability. To this end, a series of measurements were performed using a simulation tool for networks WDM called OWNS (Optical WDM Network Simulator) to perform an analysis of the problem RWA (Routing and Wavelenght Assignment) based on the algorithms studied in this article. The results of the experiments back in a different analysis where the allocation of wavelengths where overlaps in importance to routing
[show abstract][hide abstract] ABSTRACT: The Next Generation Network (NGN) holds tremendous potential, with a promise to merge the transmission of data, voice, video
and other media into a single network; unfortunately, several developing countries do not have the necessary infra-structure
to implement NGN technology. DSL (Digital Subscriber Line) technology enables a universal broadband access with reduced cost
and time required for others access networks. The environment and flow to be transmitted (within the environment) must be
analyzed and evaluated, given that the parameters obtained in this stage can prove applications to be infeasible or, at the
very least, require for an increased investment in the infrastructure. We show that the use of real measures and probabilistic
analysis will enable the planning of communication networks, considering logical and physical parameters such as loop length,
communications noises and Triple Play (voice, video and data) applications.
Future Multimedia Networking, Third International Workshop, FMN 2010, Krakow, Poland, June 17-18, 2010. Proceedings; 01/2010
[show abstract][hide abstract] ABSTRACT: The use of wireless local area networks (WLANs), as well as the proliferation of the use of multimedia applications has grown fast in recent years. Some factors affect the quality of service(QoS) received by the user. The interference is an example. This work presents an empirical study of the QoS parameters of a VoIP application in the presence of an interference network, as well as the relevance in the design of wireless networks to determine the range of an access point, taking into account several parameters as power, jitter, packet loss, delay and PMOS.
Microwave and Optoelectronics Conference (IMOC), 2009 SBMO/IEEE MTT-S International; 12/2009
[show abstract][hide abstract] ABSTRACT: The use of middleware to develop distributed applications liberates the programmer of the concerns (communication and coordination among software components) imposed by the distributed network environment. Besides these concerns, in wireless sensor networks are considered, also, their specific characteristics (address, mobility, amount and limited resources of the sensor nodes). This paper describes the implementation and performance evaluation of SensorBus, a message-oriented adaptive middleware for wireless sensor networks that uses policies to assist to the several characteristics of the wireless sensor networks. Policies are implemented in an application profile, through metadata, encoded in XML documents. Performance evaluation of SensorBus is made through their two main services: application and context. We used measurement techniques and simulation to carry out the experiments. Experiments show that using metadata to incorporate policies in the middleware does not imply undue overheads.
IEEE Latin America Transactions 01/2009; · 0.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: One of the most desired aspects for power suppliers is the acquisition/sale of energy for a future demand. However, power
consumption forecast is characterized not only by the variable of the power system itself, but also related to socio-economic
and climatic factors. Hence, it is imperative for the power suppliers to design and correlate these parameters. This paper
presents a study of power load forecast for power suppliers, comparing application of techniques of wavelets, time series
analysis methods and neural networks, considering long term forecasts; thus defining the future power consumption of a given
region. The results obtained proved to be much more effective when compared to those projected by the power suppliers based
on specialist information, thus contributing to the decision making for acquisition/sale of energy at a future demand.
Advances in Neural Networks - ISNN 2009, 6th International Symposium on Neural Networks, ISNN 2009, Wuhan, China, May 26-29, 2009, Proceedings, Part III; 01/2009
[show abstract][hide abstract] ABSTRACT: This paper proposes a strategy to associate Statecharts with a Markov Decision Process for performance evaluation. Statecharts are adapted to represent the possible decision choices and the costs incurred from decisions. Markov Decision Process is used to evaluate the long term effects of decisions. This strategy can aid users without a good knowledge of the performance evaluation process, and may participate in a more effective way in the modeling phase, providing information to make a more realistic model.
World Congress on Nature & Biologically Inspired Computing, NaBIC 2009, 9-11 December 2009, Coimbatore, India; 01/2009
[show abstract][hide abstract] ABSTRACT: This work presents results for multimedia transmission using wireless broadband networks installed in some remote cities in Amazon region. In 15 cities at State of Para, Brazil, the local government is installing wireless networks to provide wideband internet access to public agents, such as schools, hospitals, police stations and office buildings in a great project named NavegaPara. Each city has a base station working on 5.7 GHz and serving around 30 subscribers, which use an individual broadband transceiver (IBT) to access the network. The aggregate throughput (downstream + upstream) for each client is 7 Mbps, 14 Mbps or 30 Mbps depending on the installed equipment and the distance between the base station and the client unit. It is presented a typical scenario for multimedia transmission using the available infrastructure. In this case, an IBT is connected directly to a computer, which is connected to a video camera transmitting video traffic. The available infrastructure is useful for broadcasting the public television signal (Funtelpa) in uncovered areas of State of Para. Metrics such as throughput and latency are collected and analyzed. Obtained results show that multimedia transmission using NavegaPara infrastructure has satisfactory results.
[show abstract][hide abstract] ABSTRACT: This paper presents a methodology for capacity planning and performance evaluation based on hybrid approach that considers measuring and Bayesian inference applied to wireless networks, considering QoS parameters. The models take into account a crosslayer vision of networks, correlating aspects of the physical environment, on the signal propagation (power or distance) with aspects of VoIP applications (e.g., jitter and packet loss). A case study is carried out considering indoor environment (research laboratory) and outdoor environment with important characteristics of the Amazon region (e.g., densely arboreous environments).
Communications and Networking in China, 2008. ChinaCom 2008. Third International Conference on; 09/2008
[show abstract][hide abstract] ABSTRACT: This work presents an analysis based on an multimedia transmission generated on optical fiber backbone and two combined access technologies, PLC (Power Line Communications) and ADSL2+ (Asymmetric Digital Subscriber Line), called of pDSL. This paper points a case study of multimedia traffic using pDSL combination with intention to present measured and simulated results that prove the proposal solution viability.
[show abstract][hide abstract] ABSTRACT: This paper proposes a WLAN planning strategy through the use of computational intelligence and genetic algorithm. A measurement technique was used to collect data from a real WLAN network. Metrics like power, distance, delay, jitter, packet loss, throughput and PMOS were analysed through the use of bayesian networks. Finally, to optimize the QoS parameters a genetic algorithm was applied to find the best distance from the AP to support the QoS ITU-T recommendations.
Proceedings of the 5th International Conference on Mobile Technology, Applications, and Systems, Mobility Conference 2008, Yilan, Taiwan, September 10-12, 2008; 01/2008