1,720,952 research outputs found
High-Fidelity Cyber and Physical Simulation of Water Distribution Systems. I: Models and Data
No full textNumerical simulation models are a fundamental tool for planning and managing smart water networks-an evolution of water distribution systems in which physical assets are monitored and controlled by information and communication technologies. While simulation models allow us to understand the interactions between physical processes and abstract control strategies, they ignore key implementation aspects of distributed control systems, such as the required communication over digital links. As a result, the effects of anomalies and faults in the communication on the process control cannot be investigated with existing tools. In this work, we fill this gap by introducing DHALSIM (Digital HydrAuLic SIMulator), a numerical modelling platform combining EPANET-based process simulation with a network and host emulation environment, offering a high-fidelity representation of the processes occurring in the cyber domain. We illustrate DHALSIM's key functionalities by implementing it on a benchmark water distribution system, present case studies of simulated network traffic, and demonstrate how anomalies in the behavior of the communication network affect the process data received by the supervisory control and data acquisition (SCADA) server. In a companion paper, we further illustrate how DHALSIM enables research opportunities in the domain of cyber-physical security. The easily customizable and open source DHALSIM provides a "workbench" for studying smart water networks, developing digital twins, and designing a broad spectrum of engineering solutions
API evolution on Maven Central: do developers adhere to semantic versioning?
No full textIn this paper, we investigate whether developers of artifacts on Maven Central adhere to semantic versioning. We also investigate whether there is a link between violations in semantic versioning and the popularity of the violating method. Developers can violate semantic versioning by removing or altering methods in their API, which we refer to as breaking changes. They can also violate semantic versioning by extending the API in a patch version, referred to as an illegal API extension. APIs that do not keep their promise of adhering to semantic versioning, will unexpectedly break their dependents during upgrading of dependencies. We have found that these two types of violations do occur in practice. We find that 24% of analyzed artifacts contain breaking changes and 24% of artifacts contain illegal API extensions. Finally, we show that popularity of a method does not have an impact on breaking changes. We conclude that semantic versioning can not always guarantee that upgrading dependencies will not lead to incompatibility. This indicates a need for developers to be more aware of the impact that violating semantic versioning has.CSE3000 Research ProjectComputer Science and Engineerin
On the relation of method popularity to breaking changes in the Maven ecosystem
No full textSoftware reuse is a common practice in modern software engineering to save time and energy while accelerating software delivery. Dependency managers like MAVEN offer a large ecosystem of reusable libraries that build the backbone of software reuse. Breaking changes, i.e., when an update to a library introduces incompatible changes that break existing client programs, are troublesome barriers to this library reuse. Semantic Versioning has been proposed as a practice to make it easier for the users to find safe updates by encoding the change impact in the version number. While this practice is widely studied from the framework perspective, no detailed insights exist yet into the ecosystem perspective. In this work, we study violations of semantic versioning in the MAVEN ecosystem for 13,876 versions of 384 artifacts to better understand the impact these violations have on the 7,190 dependent versioned packages. We found that 67% of the artifacts introduce at least one type of semantic versioning violation, either a breaking change or an illegal API extension in their history. An impact analysis on breaking methods that (direct or transitive) dependents reference, revealed strong centralization: 87% of publicly accessible methods are never used by dependents and among methods with at least one usage, half of the unique calls from dependents concentrate on only 35% of the defined methods. We also studied method popularity and could not find an indication that popularity affects stability: even popular methods break frequently. Overall, we confirm the previous result that Semantic Versioning is violated repeatedly in practice. Our results suggest that the frequency of breaking changes might be a sign of insufficient change-impact awareness on the ecosystem and we believe that developers require more adequate information, like method popularity, to improve their update strategies.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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