104,977 research outputs found
Deriving safety cases for hierarchical structure in model-based development
No full textModel-based development and automated code generation are increasingly used for actual production code, in particular in mathematical and engineering domains. However, since code generators are typically not qualified, there is no guarantee that their output satisfies the system requirements, or is even safe. Here we present an approach to systematically derive safety cases that argue along the hierarchical structure in model-based development. The safety cases are constructed mechanically using a formal analysis, based on automated theorem proving, of the automatically generated code. The analysis recovers the model structure and component hierarchy from the code, providing independent assurance of both code and model. It identifies how the given system safety requirements are broken down into component requirements, and where they are ultimately established, thus establishing a hierarchy of requirements that is aligned with the hierarchical model structure. The derived safety cases reflect the results of the analysis, and provide a high-level argument that traces the requirements on the model via the inferred model structure to the code. We illustrate our approach on flight code generated from hierarchical Simulink models by Real-Time Worksho
Constructing a Safety Case for Automatically Generated Code from Formal Program Verification Information
No full textFormal methods can in principle provide the highest levels of assurance of code safety by providing formal proofs as explicit evidence for the assurance claims. However, the proofs are often complex and difficult to relate to the code, in particular if it has been generated automatically. They may also be based on assumptions and reasoning principles that are not justified. This causes concerns about the trustworthiness of the proofs and thus the assurance claims. Here we present an approach to systematically construct safety cases from information collected during a formal verification of the code, in particular from the construction of the logical annotations necessary for a formal, Hoare-style safety certification. Our approach combines a generic argument that is instantiated with respect to the certified safety property (i.e., safety claims) with a detailed, program-specific argument that can be derived systematically because its structure directly follows the course the annotation construction takes through the code. The resulting safety cases make explicit the formal and informal reasoning principles, and reveal the top-level assumptions and external dependencies that must be taken into account. However, the evidence still comes from the formal safety proofs. Our approach is independent of the given safety property and program, and consequently also independent of the underlying code generator. Here, we illustrate it for the AutoFilter system developed at NASA Ames
Subconjunctival Myolipoma Confirmed with Immunohistochemical Analysis: A Case Report
No full textPurpose: To report the clinicopathological features of a rare case of subconjunctival myolipoma and its treatment results.Case Report: A 17-year-old female patient referred to our center with a white-pink mass in her left upper bulbar conjunctiva. The lesion extended to the forniceal conjunctiva. The patient had otherwise normal complete ocular examinations and underwent complete surgical excision of the mass due to cosmetic concerns. The tumor was examined with light–microscopy, following hematoxylin and eosin (H&E), Masson-trichrome, and immunohistochemical (IHC) staining.A definite diagnosis of subconjunctival myolipoma was acheived following the pathological assessment. Six months postoperatively, no tumor recurrence was noted, and ocular examinations were within normal limits
Apigenin Attenuates Transverse Aortic Constriction-Induced Myocardial Hypertrophy: The Key Role of miR-185-5p/SREBP2-Mediated Autophagy [Letter]
No full textIstianah Purnamasari, Yuyun Sri Wahyuni, Hernawati Basir Department of Pharmacy, Faculty of Medicine and Health Science, Universitas Muhammadiyah Makassar, Makassar, South Sulawesi, IndonesiaCorrespondence: Istianah Purnamasari, Department of Pharmacy, Faculty of Medicine and Health Science, Universitas Muhammadiyah Makassar, Makassar, South Sulawesi, Indonesia, Email [email protected]
Safety cases for the formal verification of automatically generated code
No full textModel-based development and automated code generation are increasingly used for actual production code, in particular in mathematical and engineering domains. However, since code generators are typically not qualified, there is no guarantee that their output is correct or even safe. Formal methods which are based on mathematically-based techniques have been proposed as a means to improve software quality by providing formal safety proofs as explicit evidence for the assurance claims. However, the proofs are often complex and may also be based on assumptions and reasoning principles that are not justified. This causes concerns about the trustworthiness of the proofs and hence the assurance claims on the safety of the program. This thesis presents an approach to systematically and automatically construct comprehensive safety cases using the Goal Structuring Notation from a formal analysis of automatically generated code, based on automated theorem proving, and driven by a set of safety requirements and properties. We also present an approach to systematically derive safety cases that argue along the hierarchical structure of systems in model-based development. This core safety case is extended by separately specified auxiliary information from other verification and validation activities such as testing. The thesis also presents an approach to develop safety cases that correspond to the formal proofs found by automated theorem provers and that reveal the underlying proof argumentation structure and top-level assumptions. The resulting safety cases will make explicit the formal and informal reasoning principles, and reveal the top-level assumptions and external dependencies that must be taken into account in demonstrating software safety. The safety cases can be thought as “structured reading guide" for the software and the safety proofs that provide traceable arguments on the assurance provided. The approach has been illustrated on code generated using Real-Time Workshop for Guidance, Navigation, and Control (GN&C) systems of NASA' s Project Constellation and on code for deep space attitude estimation generated by the AutoFilter system developed at NASA Ames.<br/
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
No full textWe 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
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
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