241 research outputs found
Idmb: a tool for navigating the Inspire data model and generating an Inspire SQL database and WFS Configuration
The Inspire Data Model Browser (IDMB) is a free tool that performs the following functions: (i) it presents the Inspire UML Data Model as a tree-based structure, which is complementary to the UML diagrams; (ii) it generates a Postgis SQL Script for creating an INSPIRE compliant SQL database (Inspire Database) and a configuration file for the Deegree tool that enables the access to the Inspire Database through a Web Feature Service (WFS) producing GML according to the Inspire XML Schemas
Application of the GeoUML Tools for the Production and Validation of Inspire Datasets
The structure of INSPIRE datasets is oriented to the exchange of data, not to its storage and manipulation in a database. Therefore data transformation is required. This paper analyses the possibility of using in this context the tools developed by SpatialDBGroup at Politecnico di Milano in order to create and validate spatial databases. The considered scenario is the following one:
- an organisation (data provider) is willing to provide WFS and GML conformant to INSPIRE specifications (services and data);
- this organisation is hosting geodata related to one or more INSPIRE themes on a spatial relational database, called here Source Database
- in order to facilitate the implementation of INSPIRE compliant GML data, the organisation implements a new "INSPIRE-structured" spatial database, called here INSPIRE Database
- a Transformation Procedure is created which extracts the data from the Source Database and loads it into the INSPIRE Database
- the INSPIRE Database is "validated" also using topological operators, in order to identify also topological constraints gaps.
We assume that both the Source Database and the INSPIRE Database are SQL based and that their physical schemas have been generated by the GeoUML Catalogue tool from the corresponding conceptual schemas, called SCSOURCE and SCINSPIRE. In this scenario the availability of the conceptual schemas suggests different areas where the tools can provide a great benefit:
1. Creation of the GeoUML specification SCINSPIRE, automatic generation of the corresponding physical SQL structure and Validation of the INSPIRE Database with respect to the specification
2. (Semi)automatic generation of the Transformation Procedure using a set of correspondence rules between elements of SCSOURCE and SCINSPIRE
3. Automatic generation of the WFS configuration from the SCINSPIRE
In this paper we describe the work which has already been done and the research directions which we are following in order to deal with these points
What makes spatial data big? A discussion on how to partition spatial data
The amount of available spatial data has significantly increased in the last years so that traditional analysis tools have become inappropriate to effectively manage them. Therefore, many attempts have been made in order to define extensions of existing MapReduce tools, such as Hadoop or Spark, with spatial capabilities in terms of data types and algorithms. Such extensions are mainly based on the partitioning techniques implemented for textual data where the dimension is given in terms of the number of occupied bytes. However, spatial data are characterized by other features which describe their dimension, such as the number of vertices or the MBR size of geometries, which greatly affect the performance of operations, like the spatial join, during data analysis. The result is that the use of traditional partitioning techniques prevents to completely exploit the benefit of the parallel execution provided by a MapReduce environment. This paper extensively analyses the problem considering the spatial join operation as use case, performing both a theoretical and an experimental analysis for it. Moreover, it provides a solution based on a different partitioning technique, which splits complex or extensive geometries. Finally, we validate the proposed solution by means of some experiments on synthetic and real datasets
enabling access to cultural heritage for the visually impaired an interactive 3d model of a cultural site
Abstract We have developed low cost interactive 3D models that improve access to architectural details of cultural sites for all, including people with vision impairments. Our approach uses rapid prototyping and 3D printing along with a very small single-board computer for automating user interaction. As a case study, we developed a prototype model of "Piazza dei Miracoli" (Pisa, Italy), the famous square where the Leaning Tower is located. The system is a combination of tactile information with audio descriptions to enable potential users to explore the artifact autonomously. We exploited low-cost and partially open-source technologies, thus rendering our system easily replicable. We evaluated the interactive system with a group of eight completely blind and partially sighted users. Our user test confirmed the validity of our approach: (1) the three-dimensional models and the tactile reproduction of details obtained via a low-cost 3D printing solution are well perceived by touch; (2) the semantic aural information activated via perceptible buttons on demand and the different content levels for the audio tracks are suitable for an interactive, autonomous and satisfying exploration
Mechanochemical Preparation of Dipyridyl-Naphthalenediimide Cocrystals: Relative Role of Halogen-Bond and π-πInteractions
Naphthalenediimide derivates are a class of π-conjugated molecules largely investigated in the literature and used as building blocks for metal-organic frameworks or coformers for hydrogen-bond-based cocrystals. However, their tendency to establish halogen-bond interactions remains unexplored. By using a crystalline engineering approach, we report here four new cocrystals with N,N′-di(4-pyrydyl)-naphthalene-1,4,5,8-tetracarboxidiimide and diiodo-substituted coformers, easily obtained via a mechanochemical protocol. Cocrystals were characterized via NMR, electron ionization mass spectrometry, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Crystallographic structures were then finely examined and correlated with energy framework calculations to understand the relative contribution of halogen-bond and π-πinteractions toward framework stabilization
Establishing Robustness of a Spatial Dataset in a Tolerance-Based Vector Model
Spatial data are usually described through a vector model in which
geometries are represented by a set of coordinates embedded into an
Euclidean space. The use of a finite representation, instead of the real
numbers theoretically required, causes many robustness problems
which are well known in the literature. Such problems are made even
worse in a distributed context, where data is exchanged between different
systems and several perturbations can be introduced in the
data representation.
In order to discuss the robustness of a spatial dataset, two implementation
models have to be distinguished: the identity and the
tolerance model. The robustness of a dataset in the identity model
has been widely discussed in the literature and some algorithms of
the Snap Rounding (SR) family can be successfully applied in such
contexts. Conversely, this problem has been less explored in the tolerance
model. The aim of this article is to propose an algorithm inspired
by those of the SR family for establishing or restoring the robustness
of a vector dataset in the tolerance model. The main ideas are to
introduce an additional operation which spreads instead of snapping
geometries, in order to preserve the original relation between them,
and to use a tolerance region for such an operation instead of a single
snapping location. Finally, some experiments on real-world datasets
are presented, confirming how the proposed algorithm can establish
the robustness of a dataset
Characterization of tonsil infiltration and gene expression profile of innate sensors in PFAPA patients
Unexpected Stereoselective Access to 2-Aminooxazolines from Propargyl Ureas by Silver Salts under Mild Conditions
Propargyl ureas can lead to a range of possible heterocyclic compounds, mainly depending on the employed catalyst. Silver salts are known to promote the N-5-exo-dig cyclization mode to imidazolidinone derivatives. Conversely, a versatile and stereoselective O-5-exo-dig cyclization of propargyl ureas to 2-aminooxazolines by Ag(I) catalysis is here disclosed. Good to excellent yields and complete stereoselectivity of the external double bond have been achieved under milder reaction conditions(50–60°C). A one-po protocol starting from the corresponding propargylic amines and isocyanates has been developed as well. N,N’-Dipropargyl ureas underwent a uncommon O-5-exo-dig/N-5-endo-dig double cyclization sequence. Finally, insights into the tautomeric equilibrium of 2-aminooxazoles and on their relative reactivity are provided
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