Comunicaciones y ponencias de congresos DAC - AKS Biltzarretako komunikazioak eta txostenak

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Open Access
About the intuitionistic fuzzy set generators
(Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1997) Bustince Sola, Humberto; Mohedano Salillas, Victoria; Automática y Computación; Automatika eta Konputazioa
In this paper form the definition of intuitionistic fuzzy sets we analyze the intuitionistic fuzzy generators and the complementation in these sets. We start by defining the intuitionistic fuzzy generators in order to then study the particular cases for which this definition coincides with the fuzzy complementation. Afterwards we analyze the existence of equilibrium points, dual points and we present characterization theorems of intuitionistic fuzzy generators. Lastly, we study a manner of constructing intuitionistic fuzzy sets and analyse the structure of the complementary of intuitionistic fuzzy sets built.
Open Access
Use of CBR for IP over ATM
(SPIE, 1997) Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Donézar, C.; Automática y Computación; Automatika eta Konputazioa
Internet traffic burstiness allows for statistical multiplexing gain in the available bandwidth of an ATM link. However, a dynamic allocation bandwidth assignment (ABR) has to be performed. In this paper we evaluate the real advantages of ABR versus CBR for Internet service provisioning. We consider performance parameters such as connection setup delay and active waiting time due to flow control and show that CBR schemes can be a good alternative for Internet service provisioning over ATM networks.
Open Access
IPmiser, sistema de monitorización de enlaces ATM a 155Mbps
(1998) Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Solana, Juan Ignacio; Ariste, Teresa; Fillmore, David; Automática y Computación; Automatika eta Konputazioa
Open Access
Herramienta de gestión en tiempo real de redes de área extensa
(1998) Magaña Lizarrondo, Eduardo; Aracil Rico, Javier; Villadangos Alonso, Jesús; Automática y Computación; Automatika eta Konputazioa
This paper presents PROMIS, a new network management tool based on a distributed architecture of traffic probes. It allows network managers to monitor traffic from any wide area network segment in real time using a WWW console or a Tcl/Tk graphic interface.
Open Access
Arquitectura de publicación automatizada de contenidos educativos supervisados en Internet
(1999) Arin Irastorza, María Asunción; Magaña Lizarrondo, Eduardo; Astrain Escola, José Javier; Villadangos Alonso, Jesús; González de Mendívil Moreno, José Ramón; Automática y Computación; Automatika eta Konputazioa
This paper presents an automated publishing architecture of educational and supervised contents over the Internet. The system makes easier the job of publishing educational courses over the network using specific tools that automates the access control (CGI -- Common Gateway Interface), encrypts the information that goes through the net for not being accessed by strangers (SSL – Secure Sockets Layer), gives an statistical control of the usage of the system, and tutors the course. This project is multiplatform, i.e. all the components that integrate the system are available for any operating system (Windows 9X, Solaris, Linux,...) and it is based on the Web.
Open Access
Técnicas eficientes de filtrado y análisis de tráfico para la monitorización continua de redes de comunicaciones
(1999) Ruiz, José Javier; Magaña Lizarrondo, Eduardo; Aracil Rico, Javier; Villadangos Alonso, Jesús; Automática y Computación; Automatika eta Konputazioa
This paper presents an efficient traffic filtering and analysis architecture for network monitoring. Opposed to the usual network monitoring architectures that provide simultaneous filters as requested by managers (packet filters), we propose a different approach that aims at minimizing CPU load by avoiding unnecessary filter duplicates. Such architecture makes it possible to optimize several parallel filters execution and thus is suitable for continuous network monitoring in which it is necessary to keep track of hundreds of filters. This architecture has been implemented in a network-monitoring tool called PROMIS whose main features are detailed in this paper.
Open Access
Analysis of Internet services in IP over ATM networks
(IEEE, 1999) Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
This paper presents a trace-driven analysis of IP over ATM services from a user-perceived quality of service standpoint. QoS parameters such as the sustained throughput for transactional services and other ATM layer parameters such as the burstiness (MBS) per connection are derived. On the other hand, a macroscopic analysis that comprises percentage of flows and bytes per service, TCP transaction duration and mean bytes transferred in both ways is also presented. The traffic trace is obtained with a novel measurement equipment that combines a header extraction hardware and a high end UNIX workstation capable of providing a timestamp accuracy in the order of microseconds. The ATM link under analysis concentrates traffic from a large population of 1,500 hosts from Public University of Navarra campus network, that produce 1,700,000 TCP connections approximately in the measurement period of one week. The results obtained from such a wealth of data suggest that QoS is primarily determined by transport protocols and not by ATM bandwidth. The sustained throughput of TCP connections never grows beyond 80 Kbps with 70% probability in the data transfer phase (i. e., in the ESTABLISHED state) and we observe a strong influence of the connection establishment phase in the user-perceived throughput. On the other hand, the burstiness of individual TCP connections is rather small, namely TCP connections do not produce bursts according to the geometric law given by slow start and commonly assumed in previously published studies.
Open Access
IPmiser: herramienta de medida and análisis de redes de alta velocidad
(1999) Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
Las redes de área extensa IP generan en la actualidad un tráfico difícil de predecir y caracterizar. Así, se hace necesario disponer de herramientas que proporcionen monitorización en tiempo real de los enlaces, sin interrupción y con la máxima fiabilidad y precisión de reloj. La herramienta IPmiser consigue este objetivo mediante un hardware dedicado y una estación de trabajo para el proceso de datos, que es además servidor seguro de información de monitorización. En este artículo se presenta la arquitectura de IPmiser, junto con los resultados más destacables de diversas mediciones en el enlace IP sobre ATM de la Universidad Publica de Navarra.
Open Access
Characterizing Internet load as a non-regular multiplex of TCP streams
(IEEE, 2000) Aracil Rico, Javier; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
A commonly accepted traffic model for a large population of Internet users consists of a multiplex of Poisson-arriving heavy-tailed streams with the same constant rate (M/G//spl infin/). We show that even though such a regular model provides an accurate description of long-range dependence, the marginal distribution variance is underestimated, resulting in erroneous calculation of overflow probability in network simulations. On the other hand, we show that the traffic variability due to the marginal distribution variance can be the limiting factor for performance in the gigabit-speed next-generation Internet, rather than the long-range dependence features present in today's traffic.
Open Access
On fuzzy orderings of crisp and fuzzy intervals
(EUSFLAT, 2001) Fuentes González, Ramón; Burillo López, Pedro; Mayor, Gaspar; Automática y Computación; Automatika eta Konputazioa
First, fuzzy membership functions for the assertion '[x,y] is a positive interval' are proposed and characterized via non-decreasing real maps. Last, using those functions together with the intervaldifference and the notion of average index, comparison indexes between intervals and the ones between fuzzy intervals are proposed.
Open Access
Garantía de calidad de servicio basada en la predicción del ancho de banda
(2001) Villadangos Alonso, Jesús; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
This paper presents the architecture and performance evaluation of a neuronal estimator to predict network load in communication networks. System benchmarks are tested with real network traffic picked up from the 155 Mbps ATM Internet connection of the Universidad Pública de Navarra. The system shows good benefits in traffic prediction with 3 and 5 hours of advance. So the system shows characteristic of great interest to carry out the dynamic assignment of bandwidth in Internet Service Providers (ISPs), guaranteeing quality of service hired by the users.
Open Access
A-priori flow bandwidth estimates for dynamic bandwidth allocation in ISP access links
(2001) Aracil Rico, Javier; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
In this paper we study a-priori bandwidth estimation algorithms for TCP flows. An RTT-based bandwidth allocator is proposed, which outperforms a broad class of peak-rate and static allocation flow switching solutions. Our findings suggest that a-priori bandwidth estimation (i.e, before the TCP data transfer phase takes place) is indeed feasible and serves to design simple, yet efficient, dynamic bandwidth allocation rules for ISP access links.
Open Access
Predicción de tráfico de Internet and aplicaciones
(2001) Bernal, I.; Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Díez Marca, L. A.; Automática y Computación; Automatika eta Konputazioa
In this paper we focus on traffic prediction as a means to achieve dynamic bandwidth allocation in a generic Internet link. Our findings show that coarse prediction (bytes per interval) proves advantageous to perform dynamic link dimensioning, even if we consider a part of the top traffic producers in the traffic predictor.
Open Access
Adjusting fuzzy automata for string similarity measuring
(EUSFLAT, 2001) Astrain Escola, José Javier; Villadangos Alonso, Jesús; González de Mendívil Moreno, José Ramón; Garitagoitia Padrones, José Ramón; Fariña Figueredo, Federico; Ingeniería Matemática e Informática; Matematika eta Informatika Ingeniaritza; Automática y Computación; Automatika eta Konputazioa
In this paper, we introduce a fuzzy automaton for computing the similarity between pairs of strings and a genetic method for adjusting its parameters. The fuzzy automaton models the edit operations needed to transform any string into another one. The selection of appropriate fuzzy operations and fuzzy membership values for the transitions leads to improve the system performance for a particular application.
Open Access
Traffic estimation in high-speed communication networks using fuzzy systems
(EUSFLAT, 2001) Magaña Lizarrondo, Eduardo; Villadangos Alonso, Jesús; Astrain Escola, José Javier; Automática y Computación; Automatika eta Konputazioa
We present a practical application of fuzzy systems in communication networks. In this case a fuzzy relational model is developed to estimate the bytes transferred every time unit over a communication link. Such estimation is useful to provide an algorithm to dynamically reserve resources in order to guaranty the quality of service of the communications. In order to evaluate the fuzzy estimator we apply the information about the whole IP packets received at the router of the Public University of Navarra along two months. The estimator predicts the load of the communication link 1, 2, 4 and 6 hours before. The results show that the estimator can be used to dynamically assign bandwidth for communication services.
Open Access
On linear prediction of Internet traffic for packet and burst switching networks
(IEEE, 2001) Morató Osés, Daniel; Aracil Rico, Javier; Díez Marca, L. A.; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
In this paper, we show that prediction algorithms in the least mean square error sense prove better in a burst rather than in a packet switching network. For the latter, further information about the packet arrival distribution within the prediction interval is required. Regarding burst switching, we compare Optical Burst Switching networks with and without linear prediction to conclude that linear prediction provides a significant improvement in end-to-end latency with low bandwidth waste.
Open Access
Planificación de la calidad de servicio para el acceso a Internet de las operadoras de cable
(2002) Magaña Lizarrondo, Eduardo; Villadangos Alonso, Jesús; Izkue Mendi, Edurne; Automática y Computación; Automatika eta Konputazioa
In this paper, the data traffic generated by users of cablemodems is studied. This service must be guaranteed for accomplishing certain Quality of Service and limiting the maximum bandwidth per user. The analysis presents the differences between guaranteed UDP and TCP traffic, and how the excess of bandwidth is borrowed between users. This allows a very good utilization of network resources, and at the same time, a limitation of maximum bandwidth per user.
Open Access
Internet technologies course with combined professor and on-line contents methodology
(IEEE, 2003) Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
In this paper we present the experience and results in the teaching of a course titled “Internet Technologies”. This course, offered in Public University of Navarra (Spain), uses a special methodology that combines in-classroom lectures in front of computers with on-line contents. The students work on the on-line course lesson at the same time that the professor is available in the classroom to help the students during the hours assigned to the course. The tool used to manage the on-line contents, tests, exercises and grades, was designed specially for this course. It incorporates a student profile classification based on the time used to solve the tests.
Open Access
IP traffic prediction and equivalent bandwidth for DAMA TDMA protocols
(IEEE, 2003) Aracil Rico, Javier; Izal Azcárate, Mikel; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
The use of IP traffic prediction techniques for DAMA TDMA protocols is investigated in this paper. The predicted traffic distribution is derived when the input traffic shows long-range dependence features. Furthermore, an equivalent bandwidth is calculated, which allows the wireless terminal to request a certain amount of bandwidth (slot duration) in terms of a target traffic loss probability. The numerical results indicate very good traffic prediction capabilities, together with moderate bandwidth loss.
Open Access
Multiresolution analysis of optical burst switching traffic
(IEEE, 2003) Aracil Rico, Javier; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
In this paper, a Multiresolution Analysis is conducted in order to study the self-similar features of Optical Burst Switching (OBS) traffi c. The scenario consists of an OBS backbone with input traffic from a large number of Internet users, that generate Poisson-arriving heavytailed bursts. The results show that long-range dependence is preserved at timescales longer than the burst assembly timeout value while the traffic variability at short timescales is increased.