430 research outputs found
On Formalizing UML and OCL Features and Their Employment to Runtime Verification
Model-driven development (MDD) has been identified as a promising approach for developing software. By using abstract models of a system and by generating parts of the system out of these models, one tries to improve the efficiency of the overall development process and the quality of the resulting software. In the context of MDD the Unified Modeling Language (UML) and its related textual Object Constraint Language (OCL) have gained a high recognition. To be able to generate systems of high quality and to allow for interoperability between modeling tools, a well-defined semantics for these languages is required. This thesis summarizes published work in this context that employs an endogenous metamodeling approach to define the semantics of newer elements of the UML. While the covered elements are exhaustively used to define relations between elements of the metamodel of the UML, the UML specification leaves out a precise definition of their semantics. Our proposed approach uses models, not only to define the abstract syntax, but also to define the semantics of UML. By using UML and OCL for this, existing modeling tools can be used to validate the definition. The second part of this thesis covers work on the usage of UML and OCL models for runtime verification. It is shown how models can still be used at the end of a software development process, i. e., after an implementation has manually been added to generated parts, even though they are not used as central parts of the development process. This work also influenced the integration of protocol state machines into a modeling tool, which lead to publications about the runtime semantics of state machines and the capabilities to declaratively specify behavior using state machines
DATABASE APPROACH FOR MULTIPLE-CRITERIA DECISION SUPPORT SYSTEMS
This paper focuses on data management aspects of computerized
decision support systems which use interactive multiple criteria
decision methods. In this context, we point out the technical
requirements for such systems and the importance of the data
management tool to MCDSS.
After a discussion of candidate data models (i.e.
relational, hierarchical, and network), we examine the criteria to
use in choosing the data model for MCDSS.
In the last part of this paper, we review some database
management services which support data definition, data
manipulation, and data integrity within the multiple-criteria
decision making framework. These services guide us when designing
the appropriate architecture for the MCDSSâs data component.Information Systems Working Papers Serie
Community Intercomparison Suite (CIS) v1.4.0: a tool for intercomparing models and observations
The Community Intercomparison Suite (CIS) is an easy-to-use command-line tool which has been developed to allow the straightforward intercomparison of remote sensing, in situ and model data. While there are a number of tools available for working with climate model data, the large diversity of sources (and formats) of remote sensing and in situ measurements necessitated a novel software solution. Developed by a professional software company, CIS supports a large number of gridded and ungridded data sources "out-of-the-box", including climate model output in NetCDF or the UK Met Office pp file format, CloudSat, CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), MODIS (MODerate resolution Imaging Spectroradiometer), Cloud and Aerosol CCI (Climate Change Initiative) level 2 satellite data and a number of in situ aircraft and ground station data sets. The open-source architecture also supports user-defined plugins to allow many other sources to be easily added. Many of the key operations required when comparing heterogenous data sets are provided by CIS, including subsetting, aggregating, collocating and plotting the data. Output data are written to CF-compliant NetCDF files to ensure interoperability with other tools and systems. The latest documentation, including a user manual and installation instructions, can be found on our website (http://cistools.net). Here, we describe the need which this tool fulfils, followed by descriptions of its main functionality (as at version 1.4.0) and plugin architecture which make it unique in the field
IVOA Recommendation: Simple Spectral Access Protocol Version 1.1
The Simple Spectral Access (SSA) Protocol (SSAP) defines a uniform interface
to remotely discover and access one dimensional spectra. SSA is a member of an
integrated family of data access interfaces altogether comprising the Data
Access Layer (DAL) of the IVOA. SSA is based on a more general data model
capable of describing most tabular spectrophotometric data, including time
series and spectral energy distributions (SEDs) as well as 1-D spectra; however
the scope of the SSA interface as specified in this document is limited to
simple 1-D spectra, including simple aggregations of 1-D spectra. The form of
the SSA interface is simple: clients first query the global resource registry
to find services of interest and then issue a data discovery query to selected
services to determine what relevant data is available from each service; the
candidate datasets available are described uniformly in a VOTable format
document which is returned in response to the query. Finally, the client may
retrieve selected datasets for analysis. Spectrum datasets returned by an SSA
spectrum service may be either precomputed, archival datasets, or they may be
virtual data which is computed on the fly to respond to a client request.
Spectrum datasets may conform to a standard data model defined by SSA, or may
be native spectra with custom project-defined content. Spectra may be returned
in any of a number of standard data formats. Spectral data is generally stored
externally to the VO in a format specific to each spectral data collection;
currently there is no standard way to represent astronomical spectra, and
virtually every project does it differently. Hence spectra may be actively
mediated to the standard SSA-defined data model at access time by the service,
so that client analysis programs do not have to be familiar with the
idiosyncratic details of each data collection to be accessed
Dealing with large schema sets in mobile SOS-based applications
Although the adoption of OGC Web Services for server, desktop and web
applications has been successful, its penetration in mobile devices has been
slow. One of the main reasons is the performance problems associated with XML
processing as it consumes a lot of memory and processing time, which are scarce
resources in a mobile device. In this paper we propose an algorithm to generate
efficient code for XML data binding for mobile SOS-based applications. The
algorithm take advantage of the fact that individual implementations use only
some portions of the standards' schemas, which allows the simplification of
large XML schema sets in an application-specific manner by using a subset of
XML instance files conforming to these schemas.Comment: 9 pages, 2 tables, 7 figure
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