Design and implementation of a solution for Vendor Managed Inventory

Vendor Managed Inventory (VMI) is a tool selected by Schneider Electric to optimize its Supply Chain. The basic principle of VMI it that the manufacturer is responsible for managing the stock of its customers, that are mainly distributors. VMI is complex since it links two different organizations with two different IT systems. Having the keys of the customers’ stock is a great responsibility, particularly today when the pressure on the costs is permanent. As a consequence, the manufacturer needs to reach high levels of performance if he wants to improve its relation with the customer. Any failure can mean a loss of business. From 2005 to 2007 Schneider Electric did a pilot experience with one of its big Dutch customer. Looking at the logistic KPIs this experience was a real success. Both companies were very happy about the results. But the resources invested by Schneider Electric in this project were quite important. This closed the door to any implementation of VMI on a larger scale. The target of my project was to improve the efficiency of our internal VMI processes in order to reduce the investment of time needed to implement and maintain new customers. An analysis of the time spent on various tasks showed that there were a lot of manual steps and operations. Furthermore the solution implemented for the first customer was complex and with limited capacities. By developing a new tool Schneider Electric could industrialize VMI. Once it has been identified that a new tool was needed, I had to define an architecture that allows: - To handle a lot of data - To implement easily new customers - To reduce significantly the time needed to run up VMI The solution is based on a set of Access databases communicating with each others. Three main databases are the core of this project. Customer’s data is stored in a specific database (one database per customer), another database is used for the interface and a third one is making the calculations and communications between the others. As a result all the operations are simplified for the user. He can carry out most of his tasks only with one click when it could take him one complete day in the past. Once this solution was developed, the first VMI customer migrated to it without any issue (Fully transparent for the customer). It has then been implemented successfully with a new customer in a record time! Unfortunately, due to the global crisis, Schneider Electric temporary decided summer 2008 to slow down the implementation of VMI since even if it is costing less today, it is still representing a cost

Success rate of a biological invasion in terms of the spatial distribution of the founding population

International audienceWe analyze the role of the spatial distribution of the initial condition in reaction-diffusion models of biological invasion. Our study shows that in the presence of an Allee effect, the precise shape of the initial (or founding) population is of critical importance for successful invasion. Results are provided for one-dimensional and two-dimensional models. In the one-dimensional case, we consider initial conditions supported by two disjoint intervals of length L/2 and separated by a distance α. Analytical as well as numerical results indicate that the critical size L∗(α) of the population, where the invasion is successful if and only if L > L∗(α), is a continuous function of α and tends to increase with α, at least when α is not too small. This result emphasizes the detrimental effect of fragmentation. In the two-dimensional case, we consider more general, stochastically generated initial conditions u0, and we provide a new and rigorous definition of the rate of fragmentation of u0. We then conduct a statistical analysis of the probability of successful invasion depending on the size of the support of u0 and the fragmentation rate of u0. Our results show that the outcome of an invasion is almost completely determined by these two parameters. Moreover, we observe that the minimum abundance required for successful invasion tends to increase in a nonlinear fashion with the fragmentation rate. This effect of fragmentation is enhanced as the strength of the Allee effect is increased

Design and implementation of a solution for Vendor Managed Inventory

Vendor Managed Inventory (VMI) is a tool selected by Schneider Electric to optimize its Supply Chain. The basic principle of VMI it that the manufacturer is responsible for managing the stock of its customers, that are mainly distributors. VMI is complex since it links two different organizations with two different IT systems. Having the keys of the customers’ stock is a great responsibility, particularly today when the pressure on the costs is permanent. As a consequence, the manufacturer needs to reach high levels of performance if he wants to improve its relation with the customer. Any failure can mean a loss of business. From 2005 to 2007 Schneider Electric did a pilot experience with one of its big Dutch customer. Looking at the logistic KPIs this experience was a real success. Both companies were very happy about the results. But the resources invested by Schneider Electric in this project were quite important. This closed the door to any implementation of VMI on a larger scale. The target of my project was to improve the efficiency of our internal VMI processes in order to reduce the investment of time needed to implement and maintain new customers. An analysis of the time spent on various tasks showed that there were a lot of manual steps and operations. Furthermore the solution implemented for the first customer was complex and with limited capacities. By developing a new tool Schneider Electric could industrialize VMI. Once it has been identified that a new tool was needed, I had to define an architecture that allows: - To handle a lot of data - To implement easily new customers - To reduce significantly the time needed to run up VMI The solution is based on a set of Access databases communicating with each others. Three main databases are the core of this project. Customer’s data is stored in a specific database (one database per customer), another database is used for the interface and a third one is making the calculations and communications between the others. As a result all the operations are simplified for the user. He can carry out most of his tasks only with one click when it could take him one complete day in the past. Once this solution was developed, the first VMI customer migrated to it without any issue (Fully transparent for the customer). It has then been implemented successfully with a new customer in a record time! Unfortunately, due to the global crisis, Schneider Electric temporary decided summer 2008 to slow down the implementation of VMI since even if it is costing less today, it is still representing a cost

Uniqueness from pointwise observations in a multi-parameter inverse problem

In this paper, we prove a uniqueness result in the inverse problem of determining several non-constant coefficients of one-dimensional reaction-diffusion equations. Such reaction-diffusion equations include the classical model of Kolmogorov, Petrovsky and Piskunov as well as more sophisticated models from biology. When the reaction term contains an unknown polynomial part of degree $N,$ with non-constant coefficients $\mu_k(x),$ our result gives a sufficient condition for the uniqueness of the determination of this polynomial part. This sufficient condition only involves pointwise measurements of the solution $u$ of the reaction-diffusion equation and of its spatial derivative $\partial u / \partial x$ at a single point $x_0,$ during a time interval $(0,\epsilon).$ In addition to this uniqueness result, we give several counter-examples to uniqueness, which emphasize the optimality of our assumptions. Finally, in the particular cases N=2 and $N=3,$ we show that such pointwise measurements can allow an efficient numerical determination of the unknown polynomial reaction term

Towards Skeleton based Reconstruction : From Projective Skeletonization to Canal Surface Estimation

International audienceWe present a novel approach to reconstruct a 3D object from images corresponding to two different viewpoints: we estimate the skeleton of the object instead of its surface. The originality of the method is to be able to reconstruct a tubular object with a limited number of input images. Unlike classical reconstruction methods, like multi-view stereo or more recently structure-from-motion, this approach does not rely on interest points but estimates the topology of the object and derives its surface. Our contribution are twofold. First, given two perspective images of the 3D shape, the projection of the skeleton is computed in 2D. Secondly the 3D skeleton is reconstructed from the two projections using triangulation and matching. A mesh is finally derived for each skeleton branch

Caractérisation de la projection du squelette d'une surface canal 3D : Application à la reconstruction 3D à partir de deux images

International audienceNous présentons dans cet article une nouvelle approche pour reconstruire un objet 3D à partir de deux images de celui-ci. L'originalité de notre approche vient du fait que nous n'estimons pas directement la surface de l'objet 3D mais son squelette. Ce travail s'appuie sur les deux contributions suivantes. Premièrement, nous décrivons la relation existant entre un squelette 3D et sa projection, orthographique ou perspective, sur un plan image. Ensuite, nous montrons comment retrouver le squelette 3D à partir de deux de ses projections. Contrairement aux méthodes de reconstruction 3D classiques qui génèrent un nuage de points sans maillage, cette approche a pour avantage de reconstruire aussi la topologie de l'objet, c'est-à-dire d'en retrouver un maillage sans traitement annexe. Nous traitons ici des objets représentables par un squelette 3D curviligne et nous supposons aussi que les points de vue sont calibrés

The spatio-temporal dynamics of neutral genetic diversity

International audienceThe notions of pulled and pushed solutions of reaction-dispersal equations introduced by Garnier et al. (2012) and Roques et al. (2012) are based on a decomposition of the solutions into several components. In the framework of population dynamics, this decomposition is related to the spatio-temporal evolution of the genetic structure of a population. The pulled solutions describe a rapid erosion of neutral genetic diversity, while the pushed solutions are associated with a maintenance of diversity. This paper is a survey of the most recent applications of these notions to several standard models of population dynamics, including reaction-diffusion equations and systems and integro-differential equations. We describe several counterintuitive results, where unfavorable factors for the persistence and spreading of a population tend to promote diversity in this population. In particular, we show that the Allee effect, the existence of a competitor species, as well as the presence of climate constraints are factors which can promote diversity during a colonization. We also show that long distance dispersal events lead to a higher diversity, whereas the existence of a nonreproductive juvenile stage does not affect the neutral diversity in a range-expanding population

Converging toward a common speech code: imitative and perceptuo-motor recalibration processes in speech production

International audienceAuditory and somatosensory systems play a key role in speech motor control. In the act of speaking, segmental speech movements are programmed to reach phonemic sensory goals, which in turn are used to estimate actual sensory feedback in order to further control production. The adult's tendency to automatically imitate a number of acoustic-phonetic characteristics in another speaker's speech however suggests that speech production not only relies on the intended phonemic sensory goals and actual sensory feedback but also on the processing of external speech inputs. These online adaptive changes in speech production, or phonetic convergence effects, are thought to facilitate conversational exchange by contributing to setting a common perceptuo-motor ground between the speaker and the listener. In line with previous studies on phonetic convergence, we here demonstrate, in a non-interactive situation of communication, online unintentional and voluntary imitative changes in relevant acoustic features of acoustic vowel targets (fundamental and first formant frequencies) during speech production and imitation. In addition, perceptuo-motor recalibration processes, or after-effects, occurred not only after vowel production and imitation but also after auditory categorization of the acoustic vowel targets. Altogether, these findings demonstrate adaptive plasticity of phonemic sensory-motor goals and suggest that, apart from sensory-motor knowledge, speech production continuously draws on perceptual learning from the external speech environment

Plasticity of sensory-motor goals in speech production: behavioral evidence from phonetic convergence and speech imitation

International audienceImitation is one of the major processes by which humans develop social interactions. In speech communication, imitative processes are used from birth to adulthood, as highlighted by children’s mimicking abilities and by adult’s tendency to automatically “imitate” a number of acoustic-phonetic characteristics in another speaker’s speech. These adaptive changes are thought to play a key role in speech development/acquisition and to facilitate conversational exchange by contributing to setting a common perceptuo-motor link between speakers. Based on acoustic analyses of speech production in various laboratory tasks, the present study aimed to better characterize sensory-to-motor adaptive processes involved in unintentional as well as voluntary speech imitation, and to test possible motor plastic changes due to auditory-motor recalibration mechanisms