422 research outputs found
Coordination of production and interstage batch delivery with outsourced distribution
No full textIn this paper, we consider coordinated production and interstage batch delivery scheduling problems, where a third-party logistics provider (3PP) delivers semi-finished products in batches from one production
location to another production location belonging to the same manufacturer. A batch cannot be delivered until all jobs of the batch are completed at the upstream stage. The 3PP is required to deliver
each product within a time T from its release at the upstream stage. We consider two transportation modes: regular transportation, for which delivery departure times are fixed at the beginning, and express
transportation, for which delivery departure times are flexible. We analyze the problems faced by the 3PP when either the manufacturer dominates or the 3PP dominates. In this context, we investigate the complexity of several problems, providing polynomiality and NP-completeness results
Comparison of the HAZOP, FMEA, FRAM, and STPA Methods for the Hazard Analysis of Automatic Emergency Brake Systems
No full textInternational audienceAbstract As autonomous vehicle (AV) intelligence for controllability continues to develop, involving increasingly complex and interconnected systems, the maturity level of AV technology increasingly depends on the systems reliability level, also considering the interactions among them. Hazard analysis is typically used to identify potential system risks and avoid loss of AV system functionality. Conventional hazard analysis methods are commonly used for traditional standalone systems. New hazard analysis methods have been developed that may be more suitable for AV system-of-systems complexity. However, a comprehensive comparison of hazard analysis methods for AV systems is lacking. In this study, the traditional hazard analysis methods, hazard and operability (HAZOP) and failure mode and effects analysis (FMEA), as well as the most recent methods, like functional resonance analysis method (FRAM) and system-theoretic process analysis (STPA), are considered for implementation in the automatic emergency braking system. This system is designed to avoid collisions by utilizing the surrounding sensors to detect objects on the road, warning drivers with alerts about any collision risk, and actuating automatic partial/full braking through calculated adaptive braking deceleration. The objective of this work is to evaluate the methods with the unified theory of acceptance and use of technology (UTAUT) approach, in terms of their applicability to AV technologies. The advantages of HAZOP, FMEA, FRAM, and STPA, as well as the possibility of combining them to achieve systematic risk identification in practice, are discussed
Digitizing Real-World Scenes from Images
No full text3D computer models are starting to play a more and more important role in our society. Realworldsituations are often too complex to explain in a 2D map and also the interest in virtualreality, serious gaming and other technologies that can be based on 3D computer models, isgrowing.Synthesis Project 2018Geomatic
Coordination d'ordonnancement de production et de distribution
No full textIn this dissertation, we aim at investigating three supply chain scheduling problems in the make-To-Order business model. The first problem is a production and interstage distribution scheduling problem in a supply chain with a manufacturer and a third-Party logistics (3PL) provider. The second problem is a production and outbound distribution scheduling problem with release dates and deadlines in a supply chain with a manufacturer, a 3PL provider and a customer. The third problem is a production and outbound distribution scheduling problem with setup times and delivery time windows in a supply chain with a manufacturer, a 3PL provider and several customers. For the three problems, we study their individual scheduling problems and coordinated scheduling problems: we propose polynomial-Time algorithms or prove the intractability of these problems, and develop exact algorithms or heuristics to solve the NP-Hard problems. We establish mechanisms of coordination and evaluate the benefits of coordination.Dans cette thèse, nous étudions trois problèmes d'ordonnancement de la chaîne logistique dans le modèle de production à la demande. Le premier problème est un problème d'ordonnancement de production et de distribution intermédiaire dans une chaîne logistique avec un producteur et un prestataire logistique. Le deuxième problème est un problème d'ordonnancement de production et de distribution aval avec des dates de début au plus tôt et des dates limites de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et un client. Le troisième problème est un problème d'ordonnancement de production et de distribution aval avec des temps de réglage et des fenêtres de temps de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et plusieurs clients. Pour les trois problèmes, nous étudions les problèmes d'ordonnancement individuels et les problèmes d'ordonnancement coordonnés. Nous proposons des algorithmes polynomiaux ou prouvons la NP-Complétude de ces problèmes, et développons des algorithmes exacts ou heuristiques pour résoudre les problèmes NP-Difficiles. Nous proposons des mécanismes de coordination et évaluons le bénéfice de la coordination
Coordination of production and distribution scheduling
No full textDans cette thèse, nous étudions trois problèmes d'ordonnancement de la chaîne logistique dans le modèle de production à la demande. Le premier problème est un problème d'ordonnancement de production et de distribution intermédiaire dans une chaîne logistique avec un producteur et un prestataire logistique. Le deuxième problème est un problème d'ordonnancement de production et de distribution aval avec des dates de début au plus tôt et des dates limites de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et un client. Le troisième problème est un problème d'ordonnancement de production et de distribution aval avec des temps de réglage et des fenêtres de temps de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et plusieurs clients. Pour les trois problèmes, nous étudions les problèmes d'ordonnancement individuels et les problèmes d'ordonnancement coordonnés. Nous proposons des algorithmes polynomiaux ou prouvons la NP-Complétude de ces problèmes, et développons des algorithmes exacts ou heuristiques pour résoudre les problèmes NP-Difficiles. Nous proposons des mécanismes de coordination et évaluons le bénéfice de la coordination.In this dissertation, we aim at investigating three supply chain scheduling problems in the make-To-Order business model. The first problem is a production and interstage distribution scheduling problem in a supply chain with a manufacturer and a third-Party logistics (3PL) provider. The second problem is a production and outbound distribution scheduling problem with release dates and deadlines in a supply chain with a manufacturer, a 3PL provider and a customer. The third problem is a production and outbound distribution scheduling problem with setup times and delivery time windows in a supply chain with a manufacturer, a 3PL provider and several customers. For the three problems, we study their individual scheduling problems and coordinated scheduling problems: we propose polynomial-Time algorithms or prove the intractability of these problems, and develop exact algorithms or heuristics to solve the NP-Hard problems. We establish mechanisms of coordination and evaluate the benefits of coordination
Coordination d'ordonnancement de production et de distribution
No full textIn this dissertation, we aim at investigating three supply chain scheduling problems in the make-To-Order business model. The first problem is a production and interstage distribution scheduling problem in a supply chain with a manufacturer and a third-Party logistics (3PL) provider. The second problem is a production and outbound distribution scheduling problem with release dates and deadlines in a supply chain with a manufacturer, a 3PL provider and a customer. The third problem is a production and outbound distribution scheduling problem with setup times and delivery time windows in a supply chain with a manufacturer, a 3PL provider and several customers. For the three problems, we study their individual scheduling problems and coordinated scheduling problems: we propose polynomial-Time algorithms or prove the intractability of these problems, and develop exact algorithms or heuristics to solve the NP-Hard problems. We establish mechanisms of coordination and evaluate the benefits of coordination.Dans cette thèse, nous étudions trois problèmes d'ordonnancement de la chaîne logistique dans le modèle de production à la demande. Le premier problème est un problème d'ordonnancement de production et de distribution intermédiaire dans une chaîne logistique avec un producteur et un prestataire logistique. Le deuxième problème est un problème d'ordonnancement de production et de distribution aval avec des dates de début au plus tôt et des dates limites de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et un client. Le troisième problème est un problème d'ordonnancement de production et de distribution aval avec des temps de réglage et des fenêtres de temps de livraison dans une chaîne logistique avec un producteur, un prestataire logistique et plusieurs clients. Pour les trois problèmes, nous étudions les problèmes d'ordonnancement individuels et les problèmes d'ordonnancement coordonnés. Nous proposons des algorithmes polynomiaux ou prouvons la NP-Complétude de ces problèmes, et développons des algorithmes exacts ou heuristiques pour résoudre les problèmes NP-Difficiles. Nous proposons des mécanismes de coordination et évaluons le bénéfice de la coordination
Road Detection from Remote Sensing Imagery
No full textRoad network maps facilitate a great number of applications in our everyday life. However, their automatic creation is a difficult task, and so far, published methodologies cannot provide reliable solutions. The common and most recent approach is to design a road detection algorithm from remote sensing imagery based on a Convolutional Neural Network, followed by a result refinement post-processing step. In this project I proposed a deep learning model that utilized the Multi-Task Learning technique to improve the performance of the road detection task by incorporating prior knowledge constraints. Multi-Task Learning is a mechanism whose objective is to improve a model's generalization performance by exploiting information retrieved from the training signals of related tasks as an inductive bias, and, as its name suggests, solve multiple tasks simultaneously. Carefully selecting which tasks will be jointly solved favors the preservation of specific properties of the target object, in this case, the road network. My proposed model is a Multi-Task Learning U-Net with a ResNet34 encoder, pre-trained on the ImageNet dataset, that solves for the tasks of Road Detection Learning, Road Orientation Learning, and Road Intersection Learning. Combining the capabilities of the U-Net model, the ResNet encoder and the constrained Multi-Task Learning mechanism, my model achieved better performance both in terms of image segmentation and topology preservation against the baseline single-task solving model. The project was based on the publicly available SpaceNet Roads Dataset.Geomatic
Random Forest Classification of three different species of trees in Delft, based on AHN point clouds: Additional Thesis
No full textTrees are an important aspect of the world around us, and play a sufficient role in our daily lives. They contribute to human health and well-being in various ways. Tree inventory and monitoring are of great interest for biomass estimations and changes in the purifying effect on the air. It is a very time consuming and cost inefficient way to check every tree in and around a city or town, therefore there is further research required in the use of AHN data. Together with the “tree information data set” formthemunicipality ofDelft, the location and the corresponding point cloud of tree different species of trees are selected. For the species of interest, Aesculus Hippocastanum, Acer Saccharinum and Platanus x Hispanica, different characteristics are determined. In this research six different characteristics are estimated; Height, Trunk Height, Normalized Trunk Height, Canopy Projected Area, Normalized Canopy Projected Area, Ratio of Diameters, Normalized Ratio of Diameter, Centre of Gravity and at least the Normalized Centre of Gravity. These characteristics are used as features for the Random Forest Classification, Consequently the Confusion Matrix is used as performance measurement. The results of a test of 30 pointclouds, per species of interest, show that the Random Forest Classification is able to classify individual trees. However, these three different species cannot by sufficiently classified using clustering
Robust Interior: Exterior Classification for 3D Models
No full textThe use of 3D models has been rapidly expanding, finding applications in bothscientific and commercial fields. One common requirement for these various applications is the geometrical and topological validity of these models. However, many models available online contain deficiencies in various forms, such as duplicated geometry, gaps in the surface, etc.. To cope with those deficiencies, a standard solution is the clean extraction of the model’s boundary, and simultaneously the model’s reconstruction in a way that its structure is valid. This thesis tackles a more generalized problem, the inside-outside classification for these models. Where many approaches might have requirements for running analysis, the methodology presented strives to robustly handle all cases. These last decades, there have been various approaches in solving the ”inside -outside classification problem”. A major attempt utilizes the winding numberalgorithm, in order to assign values to elements whose position is relevant to theinput model. By assessing that value, a decision on whether the element in question is interior or exterior is taken. Other approaches work with casting rays, or other geometric analysis to also identify the borders of a model and segment the interior from the exterior. Also, since deficiencies inhibit the kick-starting of the necessary analysis, there are methods that try to restructure said models in order to clear any existing deficiencies. The methodology within this thesis will attempt a different approach from those that have been presented until now, which is transferring the problem from three into two dimensions. The first step is introducing a planar cross section on the area of interest. From there, through some graph reconstruction, geometric and optimization applications, a valid 1-manifold boundary of the cross-section is created. On that, the application of inside-outside classification through ray casting is possible. Assessing the results of the pipeline proves that the automated process can produce valid results, for a particular point of interest, related to an input model. The pipeline has been proven to function regardless of the cutting plane’s orientation, and can handle robustly a multitude of geometrically and topologically defective models. The results from this thesis can inspire further applications, and improvements on the pipeline can further evolve the quality of its outcome.Geomatic
Structure-aware Building Mesh Simplification
No full textIn recent years, there is an ever-increasing demand — both by industry and academia — for 3D spatial information and especially, for 3D building models. One of the ways to acquire such models derives from the combination of massive point clouds with reconstruction techniques, such as Ball Pivoting and Poisson Reconstruction. The result of these techniques is the representation of individual buildings or entire urban scenes in the form of surface meshes — data structures consisting of vertices, edges and faces. Despite their usefulness for visualization purposes, the high complexity of these meshes, along with various geometric and topological flaws, stands as an obstacle to their usage in further applications, such as simulations and urban planning. To address the issue of complexity, the production of lightweight building meshes can be achieved through mesh simplification, which reduces the amount of faces used in the original representations. Moreover, simplification methods focus on conforming the resulting mesh to the original one, in order to minimize the differences between the two of them. As a consequence, simple and accurate building models are possible to be acquired, whose geometric and topological validity is yet questionable. In this thesis, we introduce a novel approach for the simplification of building models, which results into a more compact representation, free of topological defects. The main characteristic of our method is structure awareness — namely, the recovery and preservation, for the input mesh, of both its primitives and the interrelationships between them (their configuration in 3D space). This awareness asserts that the resulting mesh closely follows the original and at the same time, dictates the geometric operations needed for its construction in the first place — thus providing accuracy, along with computational efficiency. Our proposed methodology is divided into three main stages: (a) primitive detection via mesh segmentation, (b) storage of primitive interrelationships in a structure graph and (c) simplification. In particular, simplification is accomplished here by approximating the primitive borders with a building scaffold, out of which a set of candidate faces is defined. The selection of faces from the candidate set to form the simplified mesh is achieved through the formulation of a linear binary programming problem, along with certain hard constraints to ensure that this mesh is both manifold and watertight. Experimentation reveals that our simplification method is able to produce simpler representations for both closed and open building meshes, which highly conform to the initial structure and are ready to be used for spatial analysis. Additionally, a fairly good approximation of a given mesh is possible to be obtained within reasonable execution times, regardless of the initial noise level or topological invalidity. Finally, a comparative analysis shows that the accuracy of our method stands in parallel with that of other available simplification techniques.Geomatic
- …
