Using Ontologies for the Design of Data Warehouses

Obtaining an implementation of a data warehouse is a complex task that forces designers to acquire wide knowledge of the domain, thus requiring a high level of expertise and becoming it a prone-to-fail task. Based on our experience, we have detected a set of situations we have faced up with in real-world projects in which we believe that the use of ontologies will improve several aspects of the design of data warehouses. The aim of this article is to describe several shortcomings of current data warehouse design approaches and discuss the benefit of using ontologies to overcome them. This work is a starting point for discussing the convenience of using ontologies in data warehouse design.Comment: 15 pages, 2 figure

Interaction-Based Creation and Maintenance of Continuously Usable Trace Links

Traceability is a major concern for all software engineering artefacts. The core of traceability are trace links between the artefacts. Out of the links between all kinds of artefacts, trace links between requirements and source code are fundamental, since they enable the connection between the user point of view of a requirement and its actual implementation. Trace links are important for many software engineering tasks such as maintenance, program comprehension, verification, etc. Furthermore, the direct availability of trace links during a project improves the performance of developers. The manual creation of trace links is too time-consuming to be practical. Thus, traceability research has a strong focus on automatic trace link creation. The most common automatic trace link creation methods use information retrieval techniques to measure the textual similarity between artefacts. The results of the textual similarity measurement is then used to judge the creation of links between artefacts. The application of such information retrieval techniques results in a lot of wrong link candidates and requires further expert knowledge to make the automatically created links usable, insomuch as it is necessary to manually vet the link candidates. This fact prevents the usage of information retrieval techniques to create trace links continuously and directly provide them to developers during a project. Thus, this thesis addresses the problem of continuously providing trace links of a good quality to developers during a project and to maintain these links along with changing artefacts. To achieve this, a novel automatic trace link creation approach called Interaction Log Recording-based Trace Link Creation (ILog) has been designed and evaluated. ILog utilizes the interactions of developers with source code while implementing requirements. In addition, ILog uses the common development convention to provide issues' identifiers in a commit message, to assign recorded interactions to requirements. Thus ILog avoids additional manual efforts from the developers for link creation. ILog has been implemented in a set of tools. The tools enable the recording of interactions in different integrated development environments and the subsequent creation of trace links. Trace link are created between source code files which have been touched by interactions and the current requirement which is being worked on. The trace links which are initially created in this way are further improved by utilizing interaction data such as interaction duration, frequency, type, etc. and source code structure, i.e. source code references between source code files involved in trace links. ILog's link improvement removes potentially wrong links and subsequently adds further correct links. ILog was evaluated in three empirical studies using gold standards created by experts. One of the studies used data from an open source project. In the two other studies, student projects involving a real world customer were used. The results of the studies showed that ILog can create trace links with perfect precision and good recall, which enables the direct usage of the links. The studies also showed that the ILog approach has better precision and recall than other automatic trace link creation approaches, such as information retrieval. To identify trace link maintenance capabilities suitable for the integration in ILog, a systematic literature review about trace link maintenance was performed. In the systematic literature review the trace link maintenance approaches which were found are discussed on the basis of a standardized trace link maintenance process. Furthermore, the extension of ILog with suitable trace link maintenance capabilities from the approaches found is illustrated

Utilizing traceable software artifacts to improve bug localization

Die Entwicklung von Softwaresystemen ist eine komplexe Aufgabe. Qualitätssicherung versucht auftretenden Softwarefehler (bugs) in Systemen zu vermeiden, jedoch können Fehler nie ausgeschlossen werden. Sobald ein Softwarefehler entdeckt wird, wird typischerweise ein Fehlerbericht (bug report) erstellt. Dieser dient als Ausgangspunkt für den Entwickler den Fehler im Quellcode der Software zu finden und zu beheben (bug fixing). Fehlerberichte sowie weitere Softwareartefakte, z.B. Anforderungen und der Quellcode selbst, werden in Software Repositories abgelegt. Diese erlauben die Artefakte mit trace links zur Nachvollziehbarkeit (traceability) zu verknüpfen. Oftmals ist die Erstellung der trace links im Entwicklungsprozess vorgeschrieben. Dazu zählen u.a. die Luftfahrt- und Automobilindustrie, sowie die Entwicklung von medizinischen Geräten. Das Auffinden von Softwarefehlern in großen Systemen mit tausenden Artefakten ist eine anspruchsvolle, zeitintensive und fehleranfällige Aufgabe, welche eine umfangreiche Projektkenntnis erfordert. Deswegen wird seit Jahren aktiv an der Automatisierung dieses Prozesses geforscht. Weiterhin wird die manuelle Erstellung und Pflege von trace links als Belastung empfunden und sollte weitgehend automatisiert werden. In dieser Arbeit wird ein neuartiger Algorithmus zum Auffinden von Softwarefehlern vorgestellt, der aktiv die erstellten trace links ausnutzt. Die Artefakte und deren Beziehungen dienen zur Erstellung eines Nachvollziehbarkeitsgraphen, welcher analysiert wird um fehlerhafte Quellcodedateien anhand eines Fehlerberichtes zu finden. Jedoch muss angenommen werden, dass nicht alle notwendigen trace links zwischen den Softwareartefakten eines Projektes erstellt wurden. Deswegen wird ein vollautomatisierter, projektunabhängiger Ansatz vorgestellt, der diese fehlenden trace links erstellt (augmentation). Die Grundlage zur Entwicklung dieses Algorithmus ist der typische Entwicklungsprozess eines Softwareprojektes. Die entwickelten Ansätze wurden mit mehr als 32.000 Fehlerberichten von 27 Open-Source Projekten evaluiert und die Ergebnisse zeigen, dass die Einbeziehung von traceability signifikant das Auffinden von Fehlern im Quellcode verbessert. Weiterhin kann der entwickelte Augmentation Algorithmus zuverlässig fehlende trace links erstellen.The development of software systems is a very complex task. Quality assurance tries to prevent defects – software bugs – in deployed systems, but it is impossible to avoid bugs all together, especially during development. Once a bug is observed, typically a bug report is written. It guides the responsible developer to locate the bug in the project's source code, and once found to fix it. The bug reports, along with other development artifacts such as requirements and the source code are stored in software repositories. The repositories also allow to create relationships – trace links – among contained artifacts. Establishing this traceability is demanded in many domains, such as safety related ones like the automotive and aviation industry, or in development of medical devices. However, in large software systems with thousands of artifacts, especially source code files, manually locating a bug is time consuming, error-prone, and requires extensive knowledge of the project. Thus, automating the bug localization process is actively researched since many years. Further, manually creating and maintaining trace links is often considered as a burden, and there is the need to automate this task as well. Multiple studies have shown, that traceability is beneficial for many software development tasks. This thesis presents a novel bug localization algorithm utilizing traceability. The project's artifacts and trace links are used to create a traceability graph. This graph is then analyzed to locate defective source code files for a given bug report. Since the existing trace link set of a project is possibly incomplete, another algorithm is prosed to augment missing links. The algorithm is fully automated, project independent, and derived from a project's development workflow. An evaluation on more than 32,000 bug reports from 27 open-source projects shows, that incorporating traceability information into bug localization significantly improves the bug localization performance compared to two state of the art algorithms. Further, the trace link augmentation approach reliably constructs missing links and therefore simplifies the required trace maintenance

A research roadmap towards achieving scalability in model driven engineering

International audienceAs Model-Driven Engineering (MDE) is increasingly applied to larger and more complex systems, the current generation of modelling and model management technologies are being pushed to their limits in terms of capacity and eciency. Additional research and development is imperative in order to enable MDE to remain relevant with industrial practice and to continue delivering its widely recognised productivity , quality, and maintainability benefits. Achieving scalabil-ity in modelling and MDE involves being able to construct large models and domain-specific languages in a systematic manner, enabling teams of modellers to construct and refine large models in a collaborative manner, advancing the state of the art in model querying and transformations tools so that they can cope with large models (of the scale of millions of model elements), and providing an infrastructure for ecient storage, indexing and retrieval of large models. This paper attempts to provide a research roadmap for these aspects of scalability in MDE and outline directions for work in this emerging research area

Blockchain for requirements traceability: A qualitative approach

Blockchain technology has emerged as a “disruptive innovation” that has received significant attention in academic and organizational settings. However, most of the existing research is focused on technical issues of blockchain systems, overlooking the organizational perspective. This study adopted a grounded theory to unveil the blockchain implementation process in organizations from the lens of blockchain experts. The results revealed three main categories: key activities, success factors, and challenges related to blockchain implementation in organizations, the latter being identified as the core category, along with 17 other concepts. Findings suggested that the majority of blockchain projects stop at the pilot stage and outlined organizational resistance to change as the core challenge. According to the experts, the following factors contribute to the organizational resistance to change: innovation–production gap, conservative management, and centralized mentality. The study aims to contribute to the existing blockchain literature by providing a holistic and domain-agnostic view of the blockchain implementation process in organizational settings. This can potentially encourage the development and implementation of blockchain solutions and guide practitioners who are interested in leveraging the inherent benefits of this technology. In addition, the results are used to improve a blockchain-enabled requirements traceability framework proposed in our previous paper.publishedVersio

Enabling system artefact exchange and selection through a linked data layer

The use of different techniques and tools is a common practice to cover all stages in the systems development lifecycle, generating a very good number of system artefacts. Moreover, these artefacts are commonly encoded in different formats and can only be accessed, in most cases, through proprietary and non-standard protocols. This scenario can be considered a real nightmare for software or systems reuse. Possible solutions imply the creation of a real collaborative development environment where tools can exchange and share data, information and knowledge. In this context, the OSLC (Open Services for Lifecycle Collaboration) initiative pursues the creation of public specifications (data shapes) to exchange any artefact generated during the development lifecycle, by applying the principles of the Linked Data initiative. In this paper, the authors present a solution to provide a real multi-format system artefact reuse by means of an OSLC-based specification to share and exchange any artefact under the principles of the Linked Data initiative. Finally, two experiments are conducted to demonstrate the advantages of enabling an input/output interface based on an OSLC implementation on top of an existing commercial tool (the Knowledge Manager). Thus, it is possible to enhance the representation and retrieval capabilities of system artefacts by considering the whole underlying knowledge graph generated by the different system artefacts and their relationships. After performing 45 different queries over logical and physical models stored in Papyrus, IBM Rhapsody and Simulink, results of precision and recall are promising showing average values between 70-80%.The research leading to these results has received funding from the AMASS project (H2020-ECSEL grant agreement no 692474; Spain's MINECO ref. PCIN-2015-262) and the CRYSTAL project (ARTEMIS FP7-CRitical sYSTem engineering AcceLeration project no 332830-CRYSTAL and the Spanish Ministry of Industry)