On the existence of almost periodic solutions for a class of neutral delay differential equations

International audienceWe study the existence of a Besicovitch almost periodic solution for a class of second order neutral delay differential equations u''(t−r)+D_1F(u(t−r),u(t−2r),t−r)+D_2F(u(t),u(t−r),t) = 0, in a Hilbert space, under some hyptoheses on the function F(*,*,t). Here, F : H×H×R → R denotes a differentiable function, D_j, j = 1,2, denotes the partial differential with respect to the jth vector variable and r ∈ (0,∞) is a fixed real number. The approach we use is based on a variational method applied on a Hilbert space of Besicovitch almost periodic function

Belief Approach for Social Networks

Nowadays, social networks became essential in information exchange between individuals. Indeed, as users of these networks, we can send messages to other people according to the links connecting us. Moreover, given the large volume of exchanged messages, detecting the true nature of the received message becomes a challenge. For this purpose, it is interesting to consider this new tendency with reasoning under uncertainty by using the theory of belief functions. In this paper, we tried to model a social network as being a network of fusion of information and determine the true nature of the received message in a well-defined node by proposing a new model: the belief social network

Plateau du Larzac

Lien Atlas (MCC) : Dans le cadre de notre Master 2 à propos des systèmes de circulation sur la partie nord du causse du Larzac, nous avons effectué une opération de prospection inventaire le long d’anciens chemins repérés par une approche archéogéographique (études de cartes et cadastres anciens, recherche des anomalies dans le paysage, analyse spatiale et lecture d’image aériennes et satellites etc.) La forte humidité malgré la saison estivale a entraîné un regain de la végétation rendant l..

The Information City: A Framework For Information Systems Governance

Modern organizations face many external constraints arising from an external environment characterized by various economic, political, and technology-related forces that reshape business dynamics. Many authors have emphasized that information technology plays a critical role in maintaining competitive advantage of organizations. Agile Information systems are among the instruments proposed by academics and practitioners to help organizations in managing continuous change and overcoming problems induced by external pressures. Nevertheless, building an agile information system - able to support the continuously changing organizational processes – is a difficult task notably because, in each organization, information system is a stack of applications developed using methods, languages, and tools which corresponds to different periods and technology eras. The heterogeneity of information systems makes difficult both the maintenance and evolution of existing applications or the development of new applications that must be integrated in the information system. Many solutions have been proposed by academics and practitioners in order to help organizations build agile information systems. Despite their richness, the proposed solutions don’t consider the relationships between information systems agility and information systems governance. In this paper, we propose a framework - based on the city landscape metaphor - which links enterprise architecture and information systems governance

Adaptation Process for Ad hoc Routing Protocol

International audienceBecause of several constraints in ad hoc networks, an adaptive ad hoc routing protocol is increasingly required. In this paper, we propose a synopsis of an adaptation process for an adaptive ad hoc routing protocol. Next, we put into practice the analysis of the process of adaptation to mobility by realizing an adaptive routing protocol: CSR (Cluster Source Routing) which is an extension of a widely used ad hoc routing protocol: DSR (Dynamic source Routing). Mobility and density metrics are considered to CSRDSR mode switching, it moves from a flat architecture working in DSR to a virtual hierarchical architecture. With this mode switching, CSR can enhance the scalability of the DSR routing protoco

Load balancing and lifetime maximization in WSN

Workshop Univ Kyushu-INPTStrategies that balance the energy consumption of the nodes and ensure maximum network lifetime by balancing the load are proposed and analyzed. Multiple transmission power levels are used. We studied an optimal solution for calculating the hop-by-hop traffic proportions for the particular case of nodes having just two transmission power levels, and compared the results given by the heuristics with those from the optimal analytical case

Crowd-based positioning of UAVs as Access Points

Unmanned Aerial Vehicles (UAVs) can be a cost saving and easy to deploy solution to implement a temporary network infrastructure. They can act as access points in scenarios such as emergency situations, special events, or specific area monitoring. Two main deployment families can be found in the literature. The first one, the location-based family, is based on the fundamental assumption that the network user positions are known. We do believe that this could not suit the most general scenarios. On the other hand, the location-independent family can not be as efficient as the first one. The main idea in this paper is to introduce a new crowd-based family, based on a probabilistic knowledge of user positions. We then propose a self-deployment method built on a Coulomb's law analogy where users and UAVs act as electrical charges. Short range interactions are implemented through network sensing, while long range ones use a crowd-based approach. Some numerical results are depicted, showing the performance of this self-deploying mechanism as well as a comparison with a well-known clustering algorithm

Load Balancing Techniques for Lifetime Maximizing in Wireless Sensor Networks

International audienceEnergy consumption has been the focus of many studies on Wireless Sensor Networks (WSN). It is well recognized that energy is a strictly limited resource in WSNs. This limitation constrains the operation of the sensor nodes and somehow compromises the long term network performance as well as network activities. Indeed, the purpose of all application scenarios is to have sensor nodes deployed, unattended, for several months or years.This paper presents the lifetime maximization problem in “many-to-one” and “mostly-off” wireless sensor networks. In such network pattern, all sensor nodes generate and send packets to a single sink via multi-hop transmissions. We noticed, in our previous experimental studies, that since the entire sensor data has to be forwarded to a base station via multi-hop routing, the traffic pattern is highly non-uniform, putting a high burden on the sensor nodes close to the base station.In this paper, we propose some strategies that balance the energy consumption of these nodes and ensure maximum network lifetime by balancing the traffic load as equally as possible. First, we formalize the network lifetime maximization problem then we derive an optimal load balancing solution. Subsequently, we propose a heuristic to approximate the optimal solution and we compare both optimal and heuristic solutions with most common strategies such as shortest-path and equiproportional routing. We conclude that through the results of this work, combining load balancing with transmission power control outperforms the traditional routing schemes in terms of network lifetime maximization

The Dimensions of Knowledge Sharing

Many authors have come to realize that knowledge management is the key to organizational performance and survival in continuously changing economic, technological, political, and social environment. Knowledge sharing is among the main activities of the knowledge management process. Indeed, due to the division of labor and accompanying fragmentation, specialization, and distribution of knowledge, organizations create permanent or temporary units – called organizational settings – in order to achieve collective goals such as products and services development and delivery. Organizational settings are composed of organizational actors with complementary knowledge, who need to share knowledge since they can’t achieve a collective outcome individually. Therefore knowledge sharing is required either within or between organizational settings so that organizations remain productive and competitive and reach their objectives Nevertheless, as experienced by many organizations, knowledge sharing is difficult to take place in practice, whatever the strategy followed. We think that there is no silver bullet to solve the knowledge sharing problem within modern organizations. Knowledge sharing is a situated process whose improvement depends on the characteristics of organizations. In this paper, we propose a framework which identifies the main aspects of knowledge sharing – called knowledge sharing dimensions – on which it is possible to act in order to improve the knowledge sharing process

Knowledge Sharing in Computerization Projects: An Approach Based on Boundary Objects

Computerization projects play a critical role in providing applications that meet the information needs of organizations and facilitate organizational change. They functions as a channel for the transmission of knowledge from individuals, methods, and past learning. As a result, knowledge management is a prerequisite to the success of such projects. Nevertheless, sharing knowledge held by organizational actors involved in computerization projects remains a difficult goal to achieve. In this paper, we analyze the obstacles to knowledge sharing in computerization projects in terms of knowledge boundaries. Apart from this analysis, the main contribution of this paper is the proposal of an approach to knowledge sharing in computerization projects, which relies on a typology of boundary objects. A case study based on development project of a reporting tool in an insurance company, has allowed us to verify the relevance of the approach proposed in this paper, and highlight its main managerial contributions