What is "dryad"

Dryad \Dry"ad\, n. [L. dryas, pl. dryades, Gr. ?, pl. ?, fr. ? oak, tree. See Tree.] (Class. Myth.) A wood nymph; a nymph whose life was bound up with that of her tree.

1550s, from Latin dryas, from Greek dryas (plural dryades) "wood nymph," from drus (genitive dryos) "oak," from PIE *deru- "tree, wood, oak" (see tree (n.)).

n. (context Greek mythology English) In Greek myth, a female tree spirit.

1. n. a deity or nymph of the woods [syn: wood nymph]

2. [also: dryades (pl)]

The DRYAD Numeral Cipher/Authentication System (KTC 1400 D) is a simple, paper cryptographic system employed by the U.S. military for authentication and for encryption of short, numerical messages. Each unit with a radio is given a set of matching DRYAD code sheets. A single sheet is valid for a limited time (e.g. 6 hours), called a cryptoperiod.

right|framed|A sample DRYAD cipher sheet A DRYAD cipher sheet contains 25 lines or rows of scrambled letters. Each line is labeled by the letters A to Y in a column on the left of the page. Each row contains a random permutation of the letters A through Y. The letters in each row are grouped into 10 columns labeled 0 through 9. The columns under 0, 1, 2 and 5 have more letters than the other digits, which have just two each.

While crude, the DRYAD Numeral Cipher/Authentication System has the advantage of being fast, relatively easy and requires no extra equipment (such as a pencil). The presence of more cipher-text columns under the digits 0, 1, 2 and 5, is apparently intended to make ciphertext frequency analysis more difficult. But much of the security comes from keeping the cryptoperiod short.

DRYAD can be used in two modes, authentication or encryption.

Dryad (Callie Betto) is a fictional character appearing in American comic books published by Marvel Comics. Created by Nunzio DeFilippis and Christina Weir, she first appeared in New X-Men: Academy X #1.

Dryad is a fictional planet in the DC Universe. Originally referred to as Korlon, the planet first appeared in Superboy and the Legion of Super-Heroes #253 (July 1979), and was created by Gerry Conway and Joe Staton.

A dryad is a form of mythological Greek nymph associated with trees.

Dryad may also refer to:

Dryad was a research project at Microsoft Research for a general purpose runtime for execution of data parallel applications. Microsoft made several preview releases of this technology available as add-ons to Windows HPC Server 2008 R2. However, in October 2011, Microsoft discontinued active development on Dryad, shifting focus to the Apache Hadoop framework.

An application written for Dryad is modeled as a directed acyclic graph (DAG). The DAG defines the dataflow of the application, and the vertices of the graph defines the operations that are to be performed on the data. The "computational vertices" are written using sequential constructs, devoid of any concurrency or mutual exclusion semantics. The Dryad runtime parallelizes the dataflow graph by distributing the computational vertices across various execution engines (which can be multiple processor cores on the same computer or different physical computers connected by a network, as in a cluster). Scheduling of the computational vertices on the available hardware is handled by the Dryad runtime, without any explicit intervention by the developer of the application or administrator of the network. The flow of data between one computational vertex to another is implemented by using communication "channels" between the vertices, which in physical implementation is realized by TCP/IP streams, shared memory or temporary files. A stream is used at runtime to transport a finite number of structured Items.

Dryad defines a domain-specific language, which is implemented via a C++ library, that is used to create and model a Dryad execution graph. Computational vertices are written using standard C++ constructs. To make them accessible to the Dryad runtime, they must be encapsulated in a class that inherits from the GraphNode base class. The graph is defined by adding edges; edges are added by using a composition operator (defined by Dryad) that connects two graphs (or two nodes of a graph) with an edge. Managed code wrappers for the Dryad API can also be written.

There exist several high-level language compilers which use Dryad as a runtime; examples include Scope (Structured Computations Optimized for Parallel Execution) and DryadLINQ.

Dryad is an international disciplinary repository of data underlying scientific and medical publications. Dryad is a curated general-purpose repository that makes data discoverable, freely reusable, and citable. The scientific, educational, and charitable mission of Dryad is to promote the availability of data underlying findings in the scientific literature for research and educational reuse.

The vision of Dryad is a scholarly communication system in which learned societies, publishers, institutions of research and education, funding bodies and other stakeholders collaboratively sustain and promote the preservation and reuse of data underlying the scholarly literature.

Dryad aims to allow researchers to validate published findings, explore new analysis methodologies, re-purpose data for research questions unanticipated by the original authors, and perform synthetic studies such as formal meta-analyses. For many publications, existing data repositories do not capture the whole data package. As a result, many important datasets are not being preserved and are no longer available, or usable, at the time that they are sought by later investigators.

Dryad serves as a repository for tables, spreadsheets, flat files, and all other kinds of published data for which specialized repositories do not already exist. Optimally, authors submit data to Dryad in conjunction with article publication, so that links to the data can be included in the published article. All data files in Dryad are associated with a published article, and are made available for reuse under the terms of a Creative Commons Zero waiver.

Dryad is also a non-profit membership organization registered in the US, providing a forum for all stakeholders to set priorities for the repository, participate in planning, and share knowledge and coordinate action around data policies.

Dryad is listed in the Registry of Research Data Repositories re3data.org.