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2005Hatem Ben Sta, Lamjed Ben Said, , ,
Cartographies of Ontology Concepts
In ICEIS (3) (pp. 486-494)., 2005
Abstract
We are interested to study the state of the art of ontologies and to synthesize it. This paper makes a synthesis of definitions, languages, ontology classifications, ontological engineering, ontological platforms and application fields of ontologies. The objective of this study is to cover and synthesize the ontological concepts through the proposition of a whole of cartographies related to these concepts.
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2004Nadia Ben Azzouna,
Experimental analysis of the impact of peer‐to‐peer applications on traffic in commercial IP networks
European Transactions on Telecommunications, 15: 511-522., 2004
Abstract
To evaluate the impact of peer-to-peer (P2P) applications on traffic in wide area networks, we analyze measurements from a high speed IP backbone link carrying TCP traffic towards several ADSL areas. The first observations are that the prevalent part of traffic is due to P2P applications (almost 80% of total traffic) and that the usage of network becomes symmetric in the sense that customers are not only clients but also servers. This latter point is observed by the significant proportion of long flows mainly composed of ACK segments. When analyzing the bit rate created by long flows, it turns out that the TCP connections due to P2P applications have a rather small bit rate and that there is no evidence for long range dependence. These facts are intimately related to the way P2P protocols are running. We separately analyze signaling traffic and data traffic. It turns out that by adopting a suitable level of aggregation, global traffic can be described by means of usual tele-traffic models based on M/G/∞ queues with Weibullian service times.
Nadia Ben Azzouna,Charcteristic of ip traffic in commercial wide area networks
Proceedings of the International Conference on Computing, Communcations and Control Technologies (CCCT’2004), Austin, Texas (TX), 2004
Abstract
Measurements from an Internet backbone link carrying TCP traf
f
ic towards different ADSL areas are analyzed in this paper. For
traffic analysis, we adopt a flow-based approach and the popular
mice/elephants dichotomy. The originality of the experimental
data reported in this paper, when compared with previous mea
surements from very high speed backbone links, is in that com
mercial traffic comprises a significant percentage due to peer-to
peer applications. This kind of traffic exhibits some remarkable
properties in terms of mice, elephants and bit rates, which are
thoroughly described in this paper. Mice due to p2p protocols and
mice due to classical Internet applications such as HTTP, ftp, etc.
are analyzed separately. It turns out that by adopting a suitable
level of aggregation, global traffic can be described by means of
usual tele-traffic models based on M/G/∞ queues with Weibul
lian service times. The global bit rate can be approximated by the
superposition of Gaussian processes perturbed by a white noise
and does not exhibit long range dependence., Nadia Ben Azzouna,IP Traffic Classification via Blind Source Separation Based on Jacobi Algorithm
Freire, M.M., Chemouil, P., Lorenz, P., Gravey, A. (eds) Universal Multiservice Networks. ECUMN 2004. Lecture Notes in Computer Science, vol 3262. Springer, Berlin, Heidelberg., 2004
Abstract
By distinguishing long and short TCP flows, we address in this paper the problem of efficiently computing the characteristics of long flows. Instead of using time consuming off-line flow classification procedures, we investigate how flow characteristics could directly be inferred from traffic measurements by means of digital signal processing techniques. The proposed approach consists of classifying on the fly packets according to their size in order to construct two signals, one associated with short flows and the other with long flows. Since these two signals have intertwined spectral characteristics, we use a blind source separation technique in order to reconstruct the original spectral densities of short and long flow sources. The method is applied to a real traffic trace captured on a link of the France Telecom IP backbone network and proves efficient to recover the characteristics of long and short flows.
, Lilia Rejeb,Using adaptive multi-agent systems to simulate economic models
Proceedings of the Third International Joint Conference on Autonomous Agents and Multiagent Systems, 2004. AAMAS 2004., New York, NY, USA, 2004, pp. 68-75., 2004
Abstract
Economic markets are complex systems. They are characterized by a large and dynamic population of firms. To deal with this complexity, we propose an adaptive multiagent system which models a set of firms in competition with each other within a shared market. The firms are represented by agents; each firm is represented by an adaptive agent. We show the advantages of adaptive agents to represent firms. Moreover, we underline the limits of the economic models which account for the firms only and ignore the organizational forms. We propose a new adaptive multiagent model that includes the organizational forms into the economic models. We simulate this model and discuss its advantages.
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2003Nadia Ben Azzouna,
Analysis of ADSL traffic on an IP backbone link
GLOBECOM'03. IEEE Global Telecommunications Conference (IEEE Cat. No. 03CH37489), 2003
Abstract
Measurements from an Internet backbone link carrying TCP traffic towards different ADSL areas are analyzed. For traffic analysis, we adopt a flow based approach and the popular mice/elephants dichotomy, where mice refer to short traffic transfers and elephants to long transfers. The originality of the reported experimental data, when compared with previous measurements from very high speed backbone links, is that the commercial traffic includes a significant part generated by peer-to-peer applications. This kind of traffic exhibits some remarkable properties in terms of mice and elephants, as we describe. It turns out that by adopting a suitable level of aggregation, the bit rate of mice can be described by means of a Gaussian process. The bit rate of elephants is smoother than that of mice and can also be well approximated by a Gaussian process.
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2002Lamjed Ben Said, ,
Agent-based interaction analysis of consumer behavior
AAMAS '02: Proceedings of the first international joint conference on Autonomous agents and multiagent systems: part 1 Pages 184 - 190, 2002
Abstract
Our goal is to create a virtual consumer population that can be used for simulating the effects of marketing strategies in a competing market context. That requires having a consumers’ behavioral model allowing the representation of observed individual behaviors and the simulation of a large population of consumers. That also requires finding the parameters’ values characterizing the virtual population that reproduces real market evolutions. This paper proposes a consumer behavioral model based on a set of behavioral primitives such as imitation, conditioning and innovativeness, which are founded on the new concept of behavioral attitude. It shows that this model provides an interpretation of the main concepts and cognitive features, issued from marketing research and psycho-sociology works on consumption. The paper presents also the CUstomer BEhavior Simulator (CUBES), which has been realized for implementing the customer model and leading multi-agents simulations. It shows how genetic algorithms (GA), in addition to multi-agent systems, are used to fit the characteristics of the virtual consumers’ population into a global realistic market behavior.
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2001Lamjed Ben Said,
Multi-Agent Simulation of Virtual Consumer Populations in a Competitive Market
In Proceedings of the 10th European Workshop on Multi-Agent Systems, Modelling Autonomous Agents in A Multi-Agent Word. Annecy, France, May (Vol. 2, No. 4, pp. 31-43)., 2001
Abstract
No abstract available.
Lamjed Ben Said, ,Multi-agent based simulation of consumer behaviour: Towards a new marketing approach
In International Congress on Modelling and Simulation Proceedings., 2001
Abstract
Theoretical concepts dealing with consumer behaviour issues from studies led in various research areas: marketing, psychology, sociology and economics. This paper presents a multi-agent simulation of consumer behaviour based on an integrating approach. Our goal is to create virtual populations including several thousands of artificial consumers that exhibit realistic behaviours in the context of a competing market. These populations are used to test the effects of marketing strategies. Existing consumer behavioural models are not well suited for the realization of such market simulations including a large number of artificial consumers. In this work a consumer behavioural model based on the concept of behavioural attitude is introduced to solve this problem. It proposes to integrate and organize most of the fundamental notions elaborated within the aforementioned research areas.
