Search results for " Modeling"
showing 10 items of 2411 documents
Using the concept of spatial contexts for the prediction of archaeological rural settlement
2011
DACRON© 360 WOVEN: EXPERIMENTAL CHARACTERIZATION AND COMPUTATIONAL ASPECTS
2010
In this paper a first experimental study on Dacron© 360 woven constitutive behavior is presented. This woven is widely adopted in sail manufacturing, it is obtained by weaving polyethylene terephthalate (PET) yarn and it shows some peculiar features due to its own manufacturing process. The experimental tests, in terms of tensile tests and cyclic tests, clearly show the orthotropy features of the material, its high strength and deformability. The examination with optical microscope of the tested specimen allows to evidence the interaction between warp and weft yarns. The obtained results represent a first step for the definition of a correct computational approach to such materials.
Modeling crowd dynamics through coarse-grained data analysis
2018
International audience; Understanding and predicting the collective behaviour of crowds is essential to improve the efficiency of pedestrian flows in urban areas and minimize the risks of accidents at mass events. We advocate for the development of crowd traffic management systems, whereby observations of crowds can be coupled to fast and reliable models to produce rapid predictions of the crowd movement and eventually help crowd managers choose between tailored optimization strategies. Here, we propose a Bi-directional Macroscopic (BM) model as the core of such a system. Its key input is the fundamental diagram for bi-directional flows, i.e. the relation between the pedestrian fluxes and d…
Acquisition, filtering and toll data processing system for obtaining origin-destination matrix and travel times on highways
2012
This paper presents an acquisition, filtering and real-time toll data processing system that provides a base for resolution and generation of studies and models of behavior on highways. Crossing points estimation, speed calculation, study traffic flow, travel time estimation and stopping points can also be provided. The complexity of processing with supplied data volume makes indispensable a less relevant information filtering. This filtering can be done through indicators such as speed or nullity of fields and a performance improvement job in database level using views, materializations, partitioning and parallelism. A web application called MODA has been developed. This application make e…
Applying a Data Quality Model to Experiments in Software Engineering
2014
Data collection and analysis are key artifacts in any software engineering experiment. However, these data might contain errors. We propose a Data Quality model specific to data obtained from software engineering experiments, which provides a framework for analyzing and improving these data. We apply the model to two controlled experiments, which results in the discovery of data quality problems that need to be addressed. We conclude that data quality issues have to be considered before obtaining the experimental results.
ISIS: a semantic mediation model and an agent based architecture for GIS interoperability
2003
The diversity of spatial information systems promotes the need to integrate heterogeneous spatial or geographic information systems (GIS) in a cooperative environment. The paper describes the research project ISIS (Interoperable Spatial Information System) which is a semantic mediation approach to support GIS interoperability. Its key characteristic is a dynamic resolution of semantic conflicts which is adequate for achieving autonomy, flexibility and extensibility. We propose a spatial OO data model and a mediation architecture based on multi-agent paradigm to support GIS interoperability.
Spatio-temporal Schema Integration with Validation: A Practical Approach
2005
We propose to enhance a schema integration process with a validation phase employing logic-based data models. In our methodology, we validate the source schemas against the data model; the inter-schema mappings are validated against the semantics of the data model and the syntax of the correspondence language. In this paper, we focus on how to employ a reasoning engine to validate spatio-temporal schemas and describe where the reasoning engine is plugged into our integration methodology. The validation phase distinguishes our integration methodology from other approaches. We shift the emphasis on automation from the a priori discovery to the a posteriori checking of the inter-schema mapping…
The Model of Possible Web Data Retrieval
2015
In the Dempster-Shafer's theory of evidence, for incorporating uncertainty, the valuation assigns to the data tables the degrees of belief for these data. Firstly, we are looking for the answers to the following questions. Is there a valuation-based system in which combination and marginalization operate on valuations? Has this system prosperities analogical to the t-norm system? In the t-norm system of the valuation for the specific database attributes configuration can be described the algebra of possible data set in which can be interpreted the Information Retrieval Logic.
Forest of Normalized Trees: Fast and Accurate Density Estimation of Streaming Data
2018
Density estimation of streaming data is a relevant task in numerous domains. In this paper, a novel non-parametric density estimator called FRONT (forest of normalized trees) is introduced. It uses a structure of multiple normalized trees, segments the feature space of the data stream through a periodically updated linear transformation and is able to adapt to ever evolving data streams. FRONT provides accurate density estimation and performs favorably compared to existing online density estimators in terms of the average log score on multiple standard data sets. Its low complexity, linear runtime as well as constant memory usage, makes FRONT by design suitable for large data streams. Final…