1,311 research outputs found
Conceptual design framework for information visualization to support multidimensional datasets in higher education institutions
Information Visualization (InfoVis) enjoys diverse adoption and applicability because of its strength in solving the problem of information overload inherent in institutional data. Policy and decision makers of higher education institutions (HEIs)
are also experiencing information overload while interacting with studentsâ data, because of its multidimensionality. This constraints decision making processes, and therefore requires a domain-specific InfoVis conceptual design framework which
will birth the domainâs InfoVis tool. This study therefore aims to design HEI Studentsâ data-focused InfoVis (HSDI) conceptual design framework which
addresses the content delivery techniques and the systematic processes in actualizing the domain specific InfoVis. The study involved four phases: 1) a usersâ study to investigate, elicit and prioritize the studentsâ data-related explicit knowledge preferences of HEI domain policy. The corresponding studentsâ data dimensions are then categorised, 2) exploratory study through content analysis of InfoVis design literatures, and subsequent mapping with findings from the usersâ study, to propose the appropriate visualization, interaction and distortion techniques for delivering the domainâs explicit knowledge preferences, 3) conceptual development of the design framework which integrates the techniquesâ model with its design processâas identified from adaptation of software engineering and InfoVis design models, 4) evaluation of the proposed framework through expert review, prototyping, heuristics evaluation, and usersâ experience evaluation. For an InfoVis that will appropriately
present and represent the domain explicit knowledge preferences, support the studentsâ data multidimensionality and the decision making processes, the study found that: 1) mouse-on, mouse-on-click, mouse on-drag, drop down menu, push
button, check boxes, and dynamics cursor hinting are the appropriate interaction techniques,
2) zooming, overview with details, scrolling, and exploration are the appropriate distortion techniques, and 3) line chart, scatter plot, map view, bar chart and pie chart are the appropriate visualization techniques. The theoretical support to the proposed framework suggests that dictates of preattentive processing theory, cognitive-fit theory, and normative and descriptive theories must be followed for InfoVis to aid perception, cognition and decision making respectively. This study contributes to the area of InfoVis, data-driven decision making process, and HEI studentsâ data usage process
Explanation of the Model Checker Verification Results
Immer wenn neue Anforderungen an ein System gestellt werden, mĂŒssen die Korrektheit und Konsistenz der Systemspezifikation ĂŒberprĂŒft werden, was in der Praxis in der Regel manuell erfolgt. Eine mögliche Option, um die Nachteile dieser manuellen Analyse zu ĂŒberwinden, ist das sogenannte Contract-Based Design. Dieser Entwurfsansatz kann den Verifikationsprozess zur ĂberprĂŒfung, ob die Anforderungen auf oberster Ebene konsistent verfeinert wurden, automatisieren. Die Verifikation kann somit iterativ durchgefĂŒhrt werden, um die Korrektheit und Konsistenz des Systems angesichts jeglicher Ănderung der Spezifikationen sicherzustellen.
Allerdings ist es aufgrund der mangelnden Benutzerfreundlichkeit und der Schwierigkeiten bei der Interpretation von Verifizierungsergebnissen immer noch eine Herausforderung, formale AnsĂ€tze in der Industrie einzusetzen. Stellt beispielsweise der Model Checker bei der Verifikation eine Inkonsistenz fest, generiert er ein Gegenbeispiel (Counterexample) und weist gleichzeitig darauf hin, dass die gegebenen Eingabespezifikationen inkonsistent sind. Hier besteht die gewaltige Herausforderung darin, das generierte Gegenbeispiel zu verstehen, das oft sehr lang, kryptisch und komplex ist. DarĂŒber hinaus liegt es in der Verantwortung der Ingenieurin bzw. des Ingenieurs, die inkonsistente Spezifikation in einer potenziell groĂen Menge von Spezifikationen zu identifizieren.
Diese Arbeit schlĂ€gt einen Ansatz zur ErklĂ€rung von Gegenbeispielen (Counterexample Explanation Approach) vor, der die Verwendung von formalen Methoden vereinfacht und fördert, indem benutzerfreundliche ErklĂ€rungen der Verifikationsergebnisse der Ingenieurin bzw. dem Ingenieur prĂ€sentiert werden. Der Ansatz zur ErklĂ€rung von Gegenbeispielen wird mittels zweier Methoden evaluiert: (1) Evaluation anhand verschiedener Anwendungsbeispiele und (2) eine Benutzerstudie in Form eines One-Group Pretest-Posttest Experiments.Whenever new requirements are introduced for a system, the correctness and consistency of the system specification must be verified, which is often done manually in industrial settings. One viable option to traverse disadvantages of this manual analysis is to employ the contract-based design, which can automate the verification process to determine whether the refinements of top-level requirements are consistent. Thus, verification can be performed iteratively to ensure the systemâs correctness and consistency in the face of any change in specifications.
Having said that, it is still challenging to deploy formal approaches in industries due to their lack of usability and their difficulties in interpreting verification results. For instance, if the model checker identifies inconsistency during the verification, it generates a counterexample while also indicating that the given input specifications are inconsistent. Here, the formidable challenge is to comprehend the generated counterexample, which is often lengthy, cryptic, and complex. Furthermore, it is the engineerâs responsibility to identify the inconsistent specification among a potentially huge set of specifications.
This PhD thesis proposes a counterexample explanation approach for formal methods that simplifies and encourages their use by presenting user-friendly explanations of the verification results. The proposed counterexample explanation approach identifies and explains relevant information from the verification result in what seems like a natural language statement. The counterexample explanation approach extracts relevant information by identifying inconsistent specifications from among the set of specifications, as well as erroneous states and variables from the counterexample. The counterexample explanation approach is evaluated using two methods: (1) evaluation with different application examples, and (2) a user-study known as one-group pretest and posttest experiment
Reusable textual styles for domain-specific modeling languages
Domain-specific languages enable concise and precise formalization of domain concepts and promote direct employment by domain experts. Therefore, syntactic constructs are introduced to empower users to associate concepts and relationships with visual textual symbols. Model-based language engineering facilitates the description of concepts and relationships in an abstract manner. However, concrete representations are commonly attached to abstract domain representations, such as annotations in metamodels, or directly encoded into language grammar and thus introduce redundancy between metamodel elements and grammar elements. In this work we propose an approach that enables autonomous development and maintenance of domain concepts and textual language notations in a distinctive and metamodel-agnostic manner by employing style models containing grammar rule templates and injection-based property selection. We provide an implementation and showcase the proposed notationspecification language in a comparison with state of the art practices during the creation of notations for an executable domain-specific modeling language based on the Eclipse Modeling Framework and Xtext
Scientific Workflows: Past, Present and Future
International audienceThis special issue and our editorial celebrate 10 years of progress with data-intensive or scientific workflows. There have been very substantial advances in the representation of workflows and in the engineering of workflow management systems (WMS). The creation and refinement stages are now well supported, with a significant improvement in usability. Improved abstraction supports cross-fertilisation between different workflow communities and consistent interpretation as WMS evolve. Through such re-engineering the WMS deliver much improved performance, significantly increased scale and sophisticated reliability mechanisms. Further improvement is anticipated from substantial advances in optimisation. We invited papers from those who have delivered these advances and selected 14 to represent today's achievements and representative plans for future progress. This editorial introduces those contributions with an overview and categorisation of the papers. Furthermore, it elucidates responses from a survey of major workflow systems, which provides evidence of substantial progress and a structured index of related papers. We conclude with suggestions on areas where further research and development is needed and offer a vision of future research directions
Identifying Patch Correctness in Test-Based Program Repair
Test-based automatic program repair has attracted a lot of attention in
recent years. However, the test suites in practice are often too weak to
guarantee correctness and existing approaches often generate a large number of
incorrect patches.
To reduce the number of incorrect patches generated, we propose a novel
approach that heuristically determines the correctness of the generated
patches. The core idea is to exploit the behavior similarity of test case
executions. The passing tests on original and patched programs are likely to
behave similarly while the failing tests on original and patched programs are
likely to behave differently. Also, if two tests exhibit similar runtime
behavior, the two tests are likely to have the same test results. Based on
these observations, we generate new test inputs to enhance the test suites and
use their behavior similarity to determine patch correctness.
Our approach is evaluated on a dataset consisting of 139 patches generated
from existing program repair systems including jGenProg, Nopol, jKali, ACS and
HDRepair. Our approach successfully prevented 56.3\% of the incorrect patches
to be generated, without blocking any correct patches.Comment: ICSE 201
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