Search results for "Industrial engineering"
showing 10 items of 835 documents
Influence of cutting process mechanics on surface integrity and electrochemical behavior of OFHC copper
2014
The authors gratefully acknowledge the support received from IC ARTS and CEA Valduc; International audience; Superfinishing machining has a particular impact on cutting mechanics, surface integrity and local electrochemical behavior. In fact, material removal during this process induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface. However, a conventional 3D cutting process is still complex to study in terms of analytical/numerical modeling and experimental process monitoring. So, researchers are wondering if a less intricate configuration such as orthogonal cutting would be able to provide information about surface integrity as close as…
Orthogonal cutting simulation of OFHC copper using a new constitutive model considering the state of stress and the microstructure effects
2016
International audience; This work aims to develop an orthogonal cutting model for surface integrity prediction, which incorporates a new constitutive model of Oxygen Free High Conductivity (OFHC) copper. It accounts for the effects of the state of stress on the flow stress evolution up to fracture. Moreover, since surface integrity parameters are sensitive to the microstructure of the work material, this constitutive model highlights also the recrystallization effects on the flow stress. Orthogonal cutting model is validated using experimental designed cutting tests. More accurate predictions were obtained using this new constitutive model comparing to the classical Johnson-Cook model.
A Neural Network Meta-Model and its Application for Manufacturing
2015
International audience; Manufacturing generates a vast amount of data both from operations and simulation. Extracting appropriate information from this data can provide insights to increase a manufacturer's competitive advantage through improved sustainability, productivity, and flexibility of their operations. Manufacturers, as well as other industries, have successfully applied a promising statistical learning technique, called neural networks (NNs), to extract meaningful information from large data sets, so called big data. However, the application of NN to manufacturing problems remains limited because it involves the specialized skills of a data scientist. This paper introduces an appr…
Know Beyond Seeing: Combining Computer Vision with Semantic Reasoning
2018
International audience; To date, computer vision systems are limited to extract the digital data of what the cameras "see". However, the meaning of what they observe could be greatly enhanced by considering the environment and common-sense knowledge. A new approach to combine computer vision with semantic modeling has been developed. This approach extracts the knowledge from images and uses it to perform real-time reasoning according to the contextual information, events of interest and logic rules. The reasoning with image knowledge allows protecting the privacy of the users, to overcome some problems of computer vision such as occlusion and missed detections and to offer services such as …
Localization from inertial data and sporadic position measurements
2020
International audience; A novel estimation strategy for inertial navigation in indoor/outdoor environments is proposed with a specific attention to the sporadic nature of the non-periodic measurements. After introducing the inertial navigation model, we introduce an observer providing an asymptotic estimate of the plant state. We use a hybrid dynamical systems representation for our results, in order to provide an effective, and elegant theoretical framework. The estimation error dynamics with the proposed observer shows a peculiar cascaded interconnection of three subsystems (allowing for intuitive gain tuning), with perturbations occurring either on the jump or on the flow dynamics (depen…
Developing a framework for designing humanitarian blockchain projects
2021
International audience; Blockchain technology promises to improve the efficiency, transparency, and accountability of humanitarian operations. Yet at the same time, especially the humanitarian context with its characteristic volatility poses unique challenges to any technology. Most prominent are the humanitarian principles that are fundamental to humanitarian operations. These ethical principles are set to protect the most vulnerable populations. Designing blockchain projects in the humanitarian context therefore requires a systematic framework that helps humanitarians make critical choices.While some design instructions can be found for commercial applications, the humanitarian context re…
Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain
2017
In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate) of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new blo…
Convergence Analysis of Distributed Set-Valued Information Systems
2016
This paper focuses on the convergence of information in distributed systems of agents communicating over a network. The information on which the convergence is sought is not rep- resented by real numbers, as often in the literature, rather by sets. The dynamics of the evolution of information across the net- work is accordingly described by set-valued iterative maps. While the study of convergence of set-valued iterative maps is highly complex in general, this paper focuses on Boolean maps, which are comprised of arbitrary combinations of unions, intersections, and complements of sets. For these important class of systems, we provide tools to study both global and local convergence. A distr…
A branch-and-cut algorithm for the Team Orienteering Problem
2017
The Team Orienteering Problem aims at maximizing the total amount of profit collected by a fleet of vehicles while not exceeding a predefined travel time limit on each vehicle. In the last years, several exact methods based on different mathematical formulations were proposed. In this paper, we present a new two-index formulation with a polynomial number of variables and constraints. This compact formulation, reinforced by connectivity constraints, was solved by means of a branch-and-cut algorithm. The total number of instances solved to optimality is 327 of 387 benchmark instances, 26 more than any previous method. Moreover, 24 not previously solved instances were closed to optimality.
123D Catch: efficiency, accuracy, constraints and limitations in architectural heritage field
2013
Today, the accurate and detailed reconstruction of geometric models of real objects has become a common process. The diffusion of Image-based 3D modeling techniques, through image-based free, low cost and open source software, have increased drastically in the past few years, especially in the sector of Cultural Heritage (Architecture, Archeology, Urban planning). Nevertheless, web based software (ARC3D, 123D Catch, Hyp3D, my3Dscanner) offer another opportunity respect the desktop systems: they use the power of cloud computing to carry out a semi-automatic data processing. In this way is overcome the considerably slowing-down of the computer of hardware-heavy approaches. Our research inves…