Mines ParisTech

About: Mines ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Microstructure. The organization has 6564 authors who have published 11676 publications receiving 359898 citations. The organization is also known as: École nationale supérieure des mines de Paris & École des mines de Paris.

Teaching innovative design reasoning: How concept???knowledge theory can help overcome fixation effects

Abstract: How can we prepare engineering students to work collectively on innovative design issues, involving ill-defined, ???wicked??? problems? Recent works have emphasized the need for students to learn to combine divergent and convergent thinking in a collaborative, controlled manner. From this perspective, teaching must help them overcome four types of obstacles or ???fixation effects??? (FEs) that are found in the generation of alternatives, knowledge acquisition, collaborative creativity, and creativity processes. We begin by showing that teaching based on concept???knowledge (C-K) theory can help to manage FEs because it helps to clarify them and then to overcome them by providing means of action. We show that C-K theory can provide scaffolding to improve project-based learning (PBL), in what we call project-based critical learning (PBCL). PBCL helps students be critical and give due thought to the main issues in innovative design education: FEs. We illustrate the PBCL process with several cases and show precisely where the FEs appear and how students are able to overcome them. We conclude by discussing two main criteria of any teaching method, both of which are usually difficult to address in situations of innovative design teaching. First, can the method be evaluated? Second, is the chosen case ???realistic??? enough? We show that C-K-based PBCL can be rigorously evaluated by teachers, and we discuss the circumstances in which a C-K-based PBCL may or may not be realistic.

On the mechanism of unstable plastic flow in an austenitic FeMnC TWIP steel

Abstract: The complex character of plastic deformation of the austenitic steel Fe22Mn0.6C is studied at room temperature with the aid of high-frequency local extensometry. It is shown that the plastic flow instability, associated with fluctuations of the flow stress, results from quasi-continuous propagation of deformation bands along the specimen axis. This propagation mode is dominant in the entire range of the applied strain-rate from 2.1 × 10 −5 s −1 to 10 −1 s −1 . Such behavior differs from that of various alloys deforming via dislocation glide under conditions of dynamic strain ageing (Portevin-Le Chatelier effect), which is characterized by a transition from a repetitive occurrence of static deformation bands at lower strain rates to a relay-race and, finally, quasi-continuous deformation band propagation at higher strain rates. The unusual behavior of the deformation bands bears evidence to a particular kind of instability in the investigated steel. A possible role of deformation twins in the observed dynamics of plastic instability is discussed.

In-Vivo Hyperspectral Human Brain Image Database for Brain Cancer Detection

Abstract: The use of hyperspectral imaging for medical applications is becoming more common in recent years. One of the main obstacles that researchers find when developing hyperspectral algorithms for medical applications is the lack of specific, publicly available, and hyperspectral medical data. The work described in this paper was developed within the framework of the European project HELICoiD (HypErspectraL Imaging Cancer Detection), which had as a main goal the application of hyperspectral imaging to the delineation of brain tumors in real-time during neurosurgical operations. In this paper, the methodology followed to generate the first hyperspectral database of in-vivo human brain tissues is presented. Data was acquired employing a customized hyperspectral acquisition system capable of capturing information in the Visual and Near InfraRed (VNIR) range from 400 to 1000 nm. Repeatability was assessed for the cases where two images of the same scene were captured consecutively. The analysis reveals that the system works more efficiently in the spectral range between 450 and 900 nm. A total of 36 hyperspectral images from 22 different patients were obtained. From these data, more than 300 000 spectral signatures were labeled employing a semi-automatic methodology based on the spectral angle mapper algorithm. Four different classes were defined: normal tissue, tumor tissue, blood vessel, and background elements. All the hyperspectral data has been made available in a public repository.

tinySLAM: A SLAM algorithm in less than 200 lines C-language program

Abstract: This paper presents a Laser-SLAM algorithm which can be programmed in less than 200 lines C-language program. The first idea aimed to develop and implement a simple SLAM algorithm providing good performances without exceeding 200 lines in a C-language program. We use a robotic platform called MinesRover, a six wheels robot with several sensors. We based our work and calculations on a laser sensor and the odometry of the robot. The article presents the different capabilities of the platform and the way we use them in order to improve our programs. We also illustrates the difficulties encountered during the programming and testing of the algorithm. This work shows the possibility to perform complex tasks using simple and easily programmable algorithms.