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Aguilar-Garnica E.,Autonomous University of Guadalajara | Garcia-Sandoval J.P.,University of Guadalajara | Dochain D.,ICTEAM
Journal of Process Control | Year: 2016

This paper is concerned with the monitoring of a biodiesel production process, more specifically with the monitoring of the esterification of grease trap wastes, a low quality feedstock for biodiesel production typically characterized by its high content of Free Fatty Acids (FFAs). The esterification takes place in a jacketed Continuous Stirred Tank Reactor (CSTR). A reset observer is designed and applied in order to provide on-line estimation of the concentration of FFAs from temperature measurements within the CSTR. In addition, the proposed reset observer is compared to two other observers (classical fuzzy observer and extended Kalman filter). According to a multiple range test conducted for analyzing the estimation error, the monitoring task for the process under study has been better fulfilled by the reset observer which is able to update the estimation results every instant when the measurements were available. © 2016 Elsevier Ltd. All rights reserved.

Brante G.,Federal Technological University of Parana | Souza R.D.,Federal Technological University of Parana | Vandendorpe L.,ICTEAM
IEEE Wireless Communications and Networking Conference, WCNC | Year: 2012

We analyze the energy efficiency of reactive and proactive relay selection algorithms under the incremental decode-and-forward protocol. By taking into account the consumption of the RF circuitry, the transmit power, and a nonlinear model for the battery, we show that a large number of available relays can actually compromise the energy efficiency of the system. Our results show that, depending on the source to destination distance, it may be preferable to consider only a small subset of nodes and select the relay among these nodes. © 2012 IEEE.

El Soussi M.,ICTEAM | Zaidi A.,University of Marne-la-Vallee | Vandendorpe L.,ICTEAM
IEEE International Conference on Communications | Year: 2012

We1 consider a multiple access relay channel (MARC), in which a relay, based on the recently proposed compute-and-forward protocol, helps two transmitters to communicate with a common destination. The relay decodes a linear combination of the received symbols instead of the individual symbols then forwards the new symbol to the destination. The destination recovers two linear equations from the decoded signals. The two equations relate the transmitted symbols with integer coefficients at different computational rates. We propose an iterative algorithm to optimize the integer coefficients and the power allocation at the transmitters alternatively, so that the sum-rate is maximized. In each iteration, the integer coefficients are updated by solving a mixed-integer quadratic programming (MIQP) problem with quadratic constraints, while the power allocation is updated by solving a series of geometric programs using a successive convex approximation method. The simulation results show that the compute-and-forward strategy and the proposed optimization method can offer substantial gain over the standard amplify-and-forward and decode-and-forward protocols for this model. © 2012 IEEE.

Soussi M.E.,ICTEAM | Zaidi A.,University of Marne-la-Vallee | Vandendorpe L.,ICTEAM
Proceedings of the International Symposium on Wireless Communication Systems | Year: 2011

In this work 1, we study a multiaccess relay channel (MARC). The system consists of two transmitters communicating with a destination with the help of a half-duplex relay. We extend and adapt the recently proposed lattice-based compute-and-forward coding scheme to the model we study. This coding scheme can be seen as a form of some network-coding that is implemented at the relay through modulo-reduction. In this scheme, the destination decodes two linear equations with integer coefficients that relate the transmitted symbols at different computational rates. First, we discuss the design criteria, and derive the allowed computation rate. Then, we optimally allocate the different parameters by solving a series of geometric programs using successive convex approximation methods. The analysis shows that our coding scheme can offer substantial gain over the standard amplify-and-forward and decode-and-forward for this model. We illustrate our results through some numerical examples. © 2011 IEEE.

Paasch C.,ICTEAM | Ferlin S.,Simula Research Laboratory | Alay O.,Simula Research Laboratory | Bonaventure O.,ICTEAM
CSWS 2014 - Proceedings of the ACM SIGCOMM 2014 Workshop on Capacity Sharing Workshop | Year: 2014

Today many end hosts are equipped with multiple interfaces. These interfaces can be utilized simultaneously by multipath protocols to pool resources of the links in an efficient way while also providing resilience to eventual link failures. However how to schedule the data segments over multiple links is a challenging problem, and highly influences the performance of multipath protocols. In this paper, we focus on different schedulers for Multipath TCP. We first design and implement a generic modular scheduler framework that enables testing of different schedulers for Multipath TCP. We then use this framework to do an in-depth analysis of different schedulers by running emulated and real-world experiments on a testbed. We consider bulk data transfer as well as application limited traffic and identify metrics to quantify the scheduler's performance. Our results shed light on how scheduling decisions can help to improve multipath transfer. © 2014 ACM.

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