1,720,961 research outputs found
Specification and Model-driven Trace Checking of Complex Temporal Properties
Full text linkOffline trace checking is a procedure used to evaluate requirement properties over a
trace of recorded events. System properties verified in the context of trace checking can be
specified using different specification languages and formalisms; in this thesis, we consider
two classes of complex temporal properties: 1) properties defined using aggregation operators;
2) signal-based temporal properties from the Cyber Physical System (CPS) domain.
The overall goal of this dissertation is to develop methods and tools for the specification
and trace checking of the aforementioned classes of temporal properties, focusing on the
development of scalable trace checking procedures for such properties.
The main contributions of this thesis are:
i) the TEMPSY-CHECK-AG model-driven approach for trace checking of temporal properties
with aggregation operators, defined in the TemPsy-AG language;
ii) a taxonomy covering the most common types of Signal-based Temporal Properties (SBTPs)
in the CPS domain;
iii) SB-TemPsy, a trace-checking approach for SBTPs that strikes a good balance in industrial
contexts in terms of efficiency of the trace checking procedure and coverage of the most
important types of properties in CPS domains. SB-TemPsy includes: 1) SB-TemPsy-DSL,
a DSL that allows the specification of the types of SBTPs identified in the aforementioned
taxonomy, and 2) an efficient trace-checking procedure, implemented in a prototype
tool called SB-TemPsy-Check;
iv) TD-SB-TemPsy-Report, a model-driven trace diagnostics approach for SBTPs expressed
in SB-TemPsy-DSL. TD-SB-TemPsy-Report relies on a set of diagnostics patterns, i.e., undesired
signal behaviors that might lead to property violations. To provide relevant and
detailed information about the cause of a property violation, TD-SB-TemPsy-Report determines
the diagnostics information specific to each type of diagnostics pattern.
Our technological contributions rely on model-driven approaches for trace checking and
trace diagnostics. Such approaches consist in reducing the problem of checking (respectively,
determining the diagnostics information of) a property over an execution trace to the
problem of evaluating an OCL (Object Constraint Language) constraint (semantically equivalent
to ) on an instance (equivalent to ) of a meta-model of the trace. The results — in
terms of efficiency of our model-driven tools—presented in this thesis are in line with those
presented in previous work, and confirm that model-driven technologies can lead to the development
of tools that exhibit good performance from a practical standpoint, also when
applied in industrial contexts
Trace Diagnostics for Signal-based Temporal Properties
No full textTrace checking is a verification technique widely used in Cyber-physical system (CPS) development, to verify whether execution traces satisfy or violate properties expressing system requirements. Often these properties characterize complex signal behaviors and are defined using domain-specific languages, such as SB-TemPsy-DSL, a pattern-based specification language for signal-based temporal properties. Most of the trace-checking tools only yield a Boolean verdict. However, when a property is violated by a trace, engineers usually inspect the trace to understand the cause of the violation; such manual diagnostic is time-consuming and error-prone. Existing approaches that complement trace-checking tools with diagnostic capabilities either produce low-level explanations that are hardly comprehensible by engineers or do not support complex signal-based temporal properties. In this paper, we propose TD-SB-TemPsy, a trace-diagnostic approach for properties expressed using SB-TemPsy-DSL. Given a property and a trace that violates the property, TD-SB-TemPsy determines the root cause of the property violation. TD-SB-TemPsy relies on the concepts of violation cause , which characterizes one of the behaviors of the system that may lead to a property violation, and diagnoses , which are associated with violation causes and provide additional information to help engineers understand the violation cause. As part of TD-SB-TemPsy, we propose a language-agnostic methodology to define violation causes and diagnoses. In our context, its application resulted in a catalog of 34 violation causes, each associated with one diagnosis, tailored to properties expressed in SB-TemPsy-DSL. We assessed the applicability of TD-SB-TemPsy on two datasets, including one based on a complex industrial case study. The results show that TD-SB-TemPsy could finish within a timeout of 1 min for as of the trace-property combinations in the industrial dataset, yielding a diagnosis in of these cases; moreover, it also yielded a diagnosis for all the trace-property combinations in the other dataset. These results suggest that our tool is applicable and efficient in most cases
Trace-Checking Signal-based Temporal Properties: A Model-Driven Approach
No full textSignal-based temporal properties (SBTPs) characterize the behavior of a system when its inputs and outputs are signals over time; they are very common for the requirements specification of cyber-physical systems. Although there exist several specification languages for expressing SBTPs, such languages either do not easily allow the specification of important types of properties (such as spike or oscillatory behaviors), or are not supported by (efficient) trace-checking procedures. In this paper, we propose SB-TemPsy, a novel model-driven trace-checking approach for SBTPs. SB-TemPsy provides (i) SB-TemPsy-DSL, a domain-specific language that allows the specification of SBTPs covering the most frequent requirement types in cyber-physical systems, and (ii) SB-TemPsy-Check, an efficient, model-driven trace-checking procedure. This procedure reduces the problem of checking an SB-TemPsy-DSL property over an execution trace to the problem of evaluating an Object Constraint Language constraint on a model of the execution trace. We evaluated our contributions by assessing the expressiveness of SB-TemPsy-DSL and the applicability of SB-TemPsy-Check using a representative industrial case study in the satellite domain. SB-TemPsy-DSL could express 97% of the requirements of our case study and SB-TemPsy-Check yielded a trace-checking verdict in 87% of the cases, with an average checking time of 48.7 s. From a practical standpoint and compared to state-of-the-art alternatives, our approach strikes a better trade-off between expressiveness and performance as it supports a large set of property types that can be checked, in most cases, within practical time limits
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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