37,554 research outputs found

    On Varieties of Ordered Automata

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    The Eilenberg correspondence relates varieties of regular languages to pseudovarieties of finite monoids. Various modifications of this correspondence have been found with more general classes of regular languages on one hand and classes of more complex algebraic structures on the other hand. It is also possible to consider classes of automata instead of algebraic structures as a natural counterpart of classes of languages. Here we deal with the correspondence relating positive C\mathcal C-varieties of languages to positive C\mathcal C-varieties of ordered automata and we present various specific instances of this correspondence. These bring certain well-known results from a new perspective and also some new observations. Moreover, complexity aspects of the membership problem are discussed both in the particular examples and in a general setting

    The State-of-the-Art of Set Visualization

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    Sets comprise a generic data model that has been used in a variety of data analysis problems. Such problems involve analysing and visualizing set relations between multiple sets defined over the same collection of elements. However, visualizing sets is a non-trivial problem due to the large number of possible relations between them. We provide a systematic overview of state-of-the-art techniques for visualizing different kinds of set relations. We classify these techniques into six main categories according to the visual representations they use and the tasks they support. We compare the categories to provide guidance for choosing an appropriate technique for a given problem. Finally, we identify challenges in this area that need further research and propose possible directions to address these challenges. Further resources on set visualization are available at http://www.setviz.net

    Master's research project : transient migrations and responses to effective change for Mixtec indigenous youth

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    Master's Project (M.A.) University of Alaska Fairbanks, 2014This qualitative research was developed not knowing the outcome. The primary goal was to find an indigenous group that resided in the Monterey Bay region of the Central Coast of California. Thanks to the Pajaro Valley Unified School District's Migrant Education Office, this goal was accomplished by the introduction of the Mixtec culture of Oaxaca, in Southern Mexico. The research began by 'hanging out' with the Mixtecs at Adult Education English class building a trust and familiarity. Their primary language is Mixteco,. Lessons were in Spanish to learn English. The project all fell into place after being introduced to Lucia, a trilingual 25 yr. old Mixteca. The secondary goal was in understanding their environmental relationship to identity. Since the Mixtecs are immigrants it was necessary to 1) get acquainted with their history, and homeland 2) attempt to understand purpose and risks to 'sneak across the border' 3) adjustment to life in California. Eight interviews were performed. Seven interviews were in their native language, Mixteco. Lucia's interview was in English and Spanish. A hand held device recorded the interviews. All interview questions were formulated in a partnership with Lucia. The translations are composed genuinely from her indigenous perspective. To acquire first hand photos, three cameras were used by the informants as they worked 'on the job' in the agricultural fields. The interviewees from their personal files donated pictures of their Oaxacan villages. Common themes were identified and are summarized in this report. The data was collected and compiled. The research brought forth a narrative nonfiction, young adult book, requested by the Mixtec students, as the rest of this project lays it out

    Specification and Verification of Distributed Embedded Systems: A Traffic Intersection Product Family

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    Distributed embedded systems (DESs) are no longer the exception; they are the rule in many application areas such as avionics, the automotive industry, traffic systems, sensor networks, and medical devices. Formal DES specification and verification is challenging due to state space explosion and the need to support real-time features. This paper reports on an extensive industry-based case study involving a DES product family for a pedestrian and car 4-way traffic intersection in which autonomous devices communicate by asynchronous message passing without a centralized controller. All the safety requirements and a liveness requirement informally specified in the requirements document have been formally verified using Real-Time Maude and its model checking features.Comment: In Proceedings RTRTS 2010, arXiv:1009.398
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