Claude Lishou

Long-term fuzzy management of water resource systems

In the present context of water resource scarcity, a complete approach for long-term storage/transfer/distribution system management is proposed. The main management objective of such a kind of system is to manage reserves and releases so as to minimize the deficit between supply and demand by taking into account demand and contribution prediction. Thus, a sliding horizon approach and especially an adaptation procedure of weighting parameters of the minimization criterion based on fuzzy logic is implemented. This criterion adaptation concept seems entirely judicious, in view of the difficulty to define weighting parameters of such optimization problems and their influence on the relevant solution obtained. Fuzzy logic is shown to be very adequate when it comes to apprehend finely the stakes in presence in the long-term management. The long-term management problem is solved with improved heuristics using linear programming and dynamic programming in order to reduce the effects of space discretization which is so restrictive in this context. The suggested approach is applied to a case study which permits to highlight its relative simplicity of implementation.

Using state-space representation for the modelisation of photovoltaic systems

This paper is about the research carried out for a better knowledge of the microfluctuations of functioning parameters following external perturbations among photovoltaic systems. In several cases studied, it is proven that in site conditions, photovoltaic systems are submitted to many external parameters. To establish relations which can determine the importance of the fluctuations of energetic parameters of these systems, we have adopted a state-space representation. This method is useful when one deals with all parameters of a given studied system. As a result, the use of MATLAB software makes it possible to present the evolution curves of the functioning point of the pv-generator when external perturbations happen.

Wolof Speech Recognition Model of Digits and Limited-Vocabulary Based on HMM and ToolKit

This paper is concerned with Automatic Speech Recognition (ASR) using trainable systems. The aim of this work is to build acoustic models for spoken language Wolof. This is done by employing Hidden Markov Models (HMM) and using the different lexicons and knowledge bases of Wolof to train their parameters. Acoustic modeling has been worked out at a phonetic level, allowing general speech recognition applications, even though a simplified task (natural number recognition and Limited-Vocabulary Speech) has been considered for model evaluation. The work performed during the study was built on keywords of the vernacular language Wolof, based on many open source software toolkits, particularly HTK (HMM ToolKit). Much research have been developed in this area; our goal is also to find solution for an innovative approach to Speech Recognition to facilitate access to information and technology to illiterate persons, to build a phonetic crowdsourcing based on acoustic and linguistic features of local languages.

Dynamic publishing and availability management of virtual machines in Virtual Organization

Nowadays, universities and research institutes are more and more feeling the need to establish collaboration networks for sharing skills, as well as material, human, software and virtualized resources. This refers to the idea of Virtual Organizations (VOs) which allow any user of a member organization to access technological and pedagogical resources available in another partner organization. However, this collaboration, most of the time, raises some concern for member organizations. Indeed, they are afraid not to be able to use their own resources when they need to. Information on resources availability is generally static, provided at a given moment. The presence management of virtual machines with the XMPP (Extensible Messaging and Presence Protocol) protocol presents limitations in the context of a collaborative network. So, the constraints identified in terms of resource sharing, instant availability and restrictions are the main obstacles to setting up such a virtual organization. This paper aims to propose and implement an application that manages dynamic discovery and availability of shared virtual machines. The proposed system manages in real time the presence of a resource and its availability in terms of its occupation or use. The system will also allow a member organization to make its resources available and enjoy priority on its resources in case it needs to use them.

Contribution to reducing the effects of geographical separation between actors of virtual universities: Proposal of an IP-SMSC integrating value-added services solutions

This paper discusses an approach to allow virtual universities to propose as a solution one of the most used media of communication by the young people to reduce the distance effect between the different actors of the open and distance learning. In fact, this paper proposes a SMS solution based on IP protocol in a context where the various actors of an open and distance learning would communicate by means of an IP network. Its the case of the open and distance learning platforms of the Senegalese universities that are interconnected by fiber-optic via the National Network for the Higher Education and Research of the Senegal. Of course, the 3GPP proposed a SMS Center norm in Long Term Evolution (LTE) environment but it makes appeal to the use of a complex network (IP Multimedia System: IMS) which is not relevant in the context of the virtual universities already working on an IP network. The SMS Center that we proposed is capable of interoperate with the SMS Centers of the traditional Telecommunication operators and also supports value added services to allow the different actors to make use of services by sending SMS from softphones installed on their traditional phones or mobile (smartphones, tablets, laptops, etc.). Our IP-SMSC solution was freely tested in an IP environment by the actors of the Senegalese Virtual University (UVS). It allowed teachers to broadcast a message to a group of students. The solution also allow students to discuss with each other by sending SMS on educational subjects and to request for any relevant type of information such as scholarships or available marks on some given courses.

Proposal of cloud-based online laboratory model for practical training in the telecoms and networking fields

The acquisition of practical skills has been recognized for a long time ago as a crucial point in the STEM (Science Technology Engineering and Mathematics). In case of e-learning, it becomes even more difficult because the learners are physically distant from the laboratories that they must use to get these skills. This paper presents a cloud-based laboratory model that provides learners a way to achieve practical work in the telecoms and networking fields in e-Learning context. This cloud technology offers many advantages exploitable by virtual laboratories. The proposed type of laboratory is mainly based on the virtual machines. It is also dynamic which means that the laboratory instances are created on demand, and destroyed at the end of the lab. To offer remote access we use the SPICE protocol. For implementation of the laboratory, in this paper we use Open Source technologies such as OpenStack, SPICE, asterisk, OpenIMScore. The laboratory was named TLaaS (Telecom Laboratory as a Service).

Multi Agent System Application for Electrical Load Shedding Management: Experiment in Senegal Power Grid

This paper proposes a multi-agent approach for power grid load shedding programming. Known as the most complex machine ever made by man, power grid is an essential pillar of all national economies. Its complexity and size make it vulnerable. Load shedding is usually an emergency control process against electrical networks with low production capacity. In this study, a system named MASLA, a Multi Agent System based Load Shedding Algorithm, which explores the load shedding planning is proposed. In electrical distribution system, power is delivered to customers through feeders which are a combination of electrical lines and medium voltage transformer substations. Depending on its power, a feeder may serve very large number of customers of different types (industrial, residential, …). Hence, Feeder Agent and Load Agent are defined in a power grid and a negotiation takes place between them, considering customer’s level of priority to select which one will be significantly impacted in a possible emergency outage. The model is implemented using a multi agent platform and a case study using the Senegalese power grid revealed that the proposed approach is useful and feasible for companies facing frequent disruption of electricity supply.

Optimization of Practical Work for Programming Courses in the Context of Distance Education

To respond to the emergence of new technologies training, Moocs designers and their platforms are more worrying about learners with emphasis on practical work requirements essential for any technical training. Currently, solutions of practical work as a plug-in are available to extend the functionality of distance learning platforms. However these solutions, while integrating video features, audio, chat, screen sharing and audio are generic while the requirements to achieve practical work may differ depending on the specialty. For literary disciplines, learners just need to see and hear the teacher while for others like computer science, teachers and learners need to implement computer programs. Despite the existence of the Screen Sharing feature in the virtual classroom solutions, distance learning platforms do not offer the ability to properly carry out practical work in programming courses. For the latter, it is not only to have visibility into the work of a participant but to create an interactive environment between the participants. This interactivity cannot be managed with screen sharing solutions that consume much bandwidth. Thus, in this paper, we propose an optimization solution of practical work that easily integrates into a distance education platform. The proof of the relevance of our approach has been demonstrated through the implementation of a practical work programming led by a tutor and learners from remote workstations. Our solution not only have a global view of the whole teaching of practical work of the participants but also to interact with each participant while allowing others to monitor these interactions and intervene as necessary. This solution should also allow a participant to make a compilation and/or execution of code that is visible to other participants.

Challenges of integrating a VoIP communication system on a VSAT network

This paper summary whole research aimed to study integration of a VoIP communication system on the VSAT network of ASECNA, which consisted to propose a solution based on VoIP technology, allowing ASECNAs workers to communicate, from different countries and working places. However, since the ASECNAs network is based on satellite transmission, obvious difficulties (such as latency, packet loss, etc.) appear in implementing a VoIP system over this network, because VoIP is demanding in terms of quality of service (QoS). Thus, in this study, through simulations and tests in real situations, we determined technical choices to be made (software, codecs, and protocols) and corrective actions to take for the successful implementation of a VoIP based system in ASECNAs context.

Estimating number of organs using Erlang's B & C-Formulas

This paper recapitulates the work performed to study Poisson distribution model, Erlang distribution model and constraints of dimensioning a network related to these models. This paper also describes the planning tool of a network based on the models considered. We introduced the application behavior, used for packaging Erlang resources. Resources can vary from libraries to process clusters, and can be configured to run on a single processor or be distributed on a set of nodes. These studies have let us to the development of a tool for planning network, which also underlined the limits of the use of Rigaults rule.