Towards Principles for Structuring and Managing Very Large Semantic Multidimensional Data Models

The management of semantic multidimensional data models plays an important role during the phases of development and maintenance of data warehouse systems. Unfortunately, this is not done with the necessary stress by now. Reasons might be seen in the plethora of semantic notations or the insufficient tool support for multidimensional modeling. The paper on hand provides experiences gained within a project with an industry partner of the telecommunications industry. Their problem is a very huge data warehouse with more than 400 data cubes and several hundred key performance indicators. We developed a repository-based solution for managing the semantic data models. Our lessons learned show that especially for very large data models there has to be a repository based solution as well as a clear concept on how to break them up into their component pars. The aim of our principles is to increase the understandability as well as the maintainability of semantic multidimensional data models

Using Reference Models for Data Warehouse Metadata Management

Based on experience from applying the Common Warehouse Metamodel to metadata management at a large Swiss bank, the applicability of metadata reference models in complex application domains is analyzed. In order to explain the context of the case, the state-of-the-art of the Common Warehouse Metamodel and its application for data warehouse management are summarized. Based on the project experience documented in this paper, benefits of the reference model approach are described and recommendations for future developments of the Common Warehouse Metamodel are proposed

REMM-Studio: an Integrated Model-Driven Environment for Requirements Specification, Validation and Formatting

In order to integrate requirements into the current Model-Driven Engineering (MDE) approach, the traditional document-based requirements specification process should be changed into a requirements modelling process. To achieve this we propose a requirements metamodel called REMM Requirements Engineering MetaModel) which includes the elements that should appear in a requirements model (requirements, stakeholders, test cases, etc.) together with the relationships that may appear between them. This metamodel is the basis of the REMM-Studio environment which enables: (1) to build graphical requirements models, (2) to validate them against the metamodel and against a set of additional OCL constraints, and (3) to automatically generate a navigable Software Requirements Specification (SRS) document as the main deliverable of the Requirements Engineering process. REMM-Studio is expected to ease the integration of requirements with other development models (e.g. component models) and to facilitate the validation of the SRS thanks to its navigability.MEDWSA (TIN2006-15175-C05-02), DEDALO (TIN2006-15175-C05-03), DESERT (PBC-05-012-3)Escuela Técnica superior de Ingeniería Agronómic

Using domain specific languages to capture design knowledge for model-based systems engineering

Design synthesis is a fundamental engineering task that involves the creation of structure from a desired functional specification; it involves both creating a system topology as well as sizing the system's components. Although the use of computer tools is common throughout the design process, design synthesis is often a task left to the designer. At the synthesis stage of the design process, designers have an extensive choice of design alternatives that need to be considered and evaluated. Designers can benefit from computational synthesis methods in the creative phase of the design process. Recent increases in computational power allow automated synthesis methods for rapidly generating a large number of design solutions. Combining an automated synthesis method with an evaluation framework allows for a more thorough exploration of the design space as well as for a reduction of the time and cost needed to design a system. To facilitate computational synthesis, knowledge about feasible system configurations must be captured. Since it is difficult to capture such synthesis knowledge about any possible system, a design domain must be chosen. In this thesis, the design domain is hydraulic systems. In this thesis, Model-Driven Software Development concepts are leveraged to create a framework to automate the synthesis of hydraulic systems will be presented and demonstrated. This includes the presentation of a domain specific language to describe the function and structure of hydraulic systems as well as a framework for synthesizing hydraulic systems using graph grammars to generate system topologies. Also, a method using graph grammars for generating analysis models from the described structural system representations is presented. This approach fits in the context of Model-Based Systems Engineering where a variety of formal models are used to represent knowledge about a system. It uses the Systems Modeling Language developed by The Object Management Group (OMG SysML™) as a unifying language for model definition.M.S.Committee Chair: Paredis, Chris; Committee Member: McGinnis, Leon; Committee Member: Schaefer, Dir

Organising interoperability information on highly dynamic and heterogeneous environments

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de ComputadoresThe “Internet of Things” is a dynamic global network infrastructure where physical and virtual “things” communicate and share information amongst themselves. Plug and Interoperate is an approach that allows heterogeneous “things” to plug (into data) and seamlessly exchange information within the environment. To allow that, Plug and Interoperate needs to have the comprehension about the existing interoperability information. For this, the interoperability information needs to be duly organised. However, and in the “Internet of Things”, this presents major challenges. First, it is difficult to index all interoperability information due to the “things” heterogeneity (many and different languages and formats) and due to the dynamics of the system (disparate things entering/leaving the environment at all times). Also, that the environment can be used with much different purposes, which hinders the way on how the interoperability information should be organised. So, an architecture of an Interoperability Repository System is presented, in order to organise all interoperability information in this kind of environments. The solution handles heterogeneous interoperability information and allows users to add a User Space to the repository in order to customise it to specific needs. It also provides a notification mechanism in order to notify users of new or updated interoperability information

CAViT: a Consistency Maintenance Framework based on Transformation Contracts

Design by contract is a software correctness methodology for procedural and object-oriented software. It relies on logical assertions to detect implementation mistakes at run-time or to proof the absence thereof at compile-time. Design by contract has found a new application in model driven engineering, a methodology that aims to manage the complexity of frameworks by relying on models and transformations. A ``transformation contract\u27\u27 is a pair of constraints that together describe the effect of a transformation rule on the set of models contained in its transformation definition: the postcondition describes the model consistency state that the rule can establish provided that its precondition is satisfied. A transformation contract of a rule can be maintained automatically by calling the rule (1) as soon as the invariant corresponding to its postcondition is violated and (2) provided that its precondition is satisfied. Domain specific visual languages can facilitate the implementation of the actual transformation rules since they hide the complexity of graph transformation algorithms and standards for tool interoperability. In this talk, we describe CAViT: a framework that integrates a visual model transformation tool with a design by contract tool by relying on OMG standards such as UML, OCL and MOF

Consistency Modeling in a Multi-Model Architecture : Integrate and Celebrate Diversity

Central to Model-Driven Engineering (MDE) is seeing models as objects that can be handled and organized into metamodel stacks and multi-model architectures. This work contributes with a unique way of doing consistency modeling where the involved models are explicitly organized in a multi-model architecture; a general model for creating multi-model architectures that allows semantics to be attached is defined and applied; explicit attachment of semantics is demonstrated by attaching Java classes that implement different instantiation semantics in order to realize the consistency modeling and the automatic generation of consistency data. The kind of consistency addressed concerns relations between data residing in legacy databases defined by different schemas. The consistency modeling is meant to solve the problem of exposing inconsistencies by relating the data. The consistency modeling combines in a practical way visual modeling and logic (OCL). The approach is not limited to exposing inconsistencies, but may also be used to derive more general information given one or more data sets. The consistency is modeled by defining a consistency model that relates elements of two given legacy models. The consistency model is expressed in a language specially designed for consistency modeling. The language allows definition of classes, associations and invariants expressed in OCL. The interpretation of the language is special: Given one conforming data set for each of the legacy models, the consistency model may then be automatically instantiated to consistency data that tells if the data sets are consistent or not. The invariants are used to decide what instances to generate when making the consistency data. The amount of consistency data to create is finite and limited by the given data sets. The consistency model is instantiated until no more elements can be added without breaking some invariant or multiplicity. The consistency data is presented as a model which can be investigated by the user