1,721,047 research outputs found
DNAQL: a query language for DNA sticker complexes
No full textDNA computing has a rich history of computing paradigms with great expressive power. However, far less expressive power is needed for data manipulation. Indeed, the relational algebra, the yardstick of database systems, is expressible in first-order logic, and thus less powerful than Turing-complete models. Turing-complete DNA computing models have to account for many and varied scenarios. A DNA implementation of data manipulations might be nimbler and perform its operation faster than a Turing-complete DNA computing model. Hence, we propose a restrictive model for implementing data manipulation operations, focused on implementability in DNA. We call this model the sticker complex model. A forte of the sticker complex model, is its ability to detect when hybridization becomes an uncontrolled chain reaction. Such chain reactions make hybridization less predictable and thus less attractive for deterministic computations. Next, we define a query language on sticker complexes, called DNAQL. DNAQL is a typed, applicative functional programming language, powerful enough to simulate the relational algebra on sticker complexes. The type system enjoys a number of desirable properties such as soundness, maximality, and tightness.Jan Van den Bussche is partially supported by the National Natural Science Foundation of China (61972455).van den Bussche, J (corresponding author), Hasselt Univ, Hasselt, Belgium.
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Graph-Theoretic Formalization of Hybridization in DNA Sticker Complexes
No full textSticker complexes are a formal graph-based data model for a restricted class of DNA complexes, motivated by potential applications to databases. This data model allows for a purely declarative definition of hybridization. We introduce the notion of terminating hybridization, which intuitively means that only a finite number of different products can be generated. We characterize this notion in purely graph-theoretic terms. Under a finite alphabet, each product is shown to be of polynomial size. Yet, terminating hybridization can still produce results of exponential size, in that there may be exponentially many different (nonisomorphic) finished products. We indicate a class of complexes where hybridization is guaranteed to be polynomially bounded.We thank the program committee for referring us to the work of Jonoska et al. (2011)
The DNA query language DNAQL
No full textThis paper presents an exposition of the authors' past and present work on the query language DNAQL for querying databases in DNA. In DNA computing, data is represented and stored in DNA molecules. Accordingly, a logical data model is defined that models complexes of DNA molecules in a graph-oriented fashion. Next, a set of formal operations on DNA complexes is defined, much in the spirit of the operations of the relational algebra in the relational data model. These operations model laboratory operations on DNA in solution. Their combination leads to the query language DNAQL; but in order for programs to be well-defined on prescribed types of inputs, a type system is superimposed on the language. Finally a correspondence is shown between well-typed DNAQL programs and programs in a relational-algebra query language.Jan Van den Bussche would like to thank Anthony J. (Tony) Bonner for getting him interested in DNA, a long, long time ago. Tony suggested Jan to read The Cartoon Guide to Genetics [19] which Jan still highly recommends to all interested readers
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
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