Helix

A helix (pl: helixes or helices) is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helices are coil springs and the handrails of spiral staircases. A "filled-in" helix – for example, a spiral ramp – is called a helicoid. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved".

Types

Helices can be either right-handed or left-handed. With the line of sight along the helix's axis, if a clockwise screwing motion moves the helix away from the observer, then it is called a right-handed helix; if towards the observer, then it is a left-handed helix. Handedness (or chirality) is a property of the helix, not of the perspective: a right-handed helix cannot be turned to look like a left-handed one unless it is viewed in a mirror, and vice versa.

Phelix

Phelix is a high-speed stream cipher with a built-in single-pass message authentication code (MAC) functionality, submitted in 2004 to the eSTREAM contest by Doug Whiting, Bruce Schneier, Stefan Lucks, and Frédéric Muller. The cipher uses only the operations of addition modulo 2³², exclusive or, and rotation by a fixed number of bits. Phelix uses a 256-bit key and a 128-bit nonce, claiming a design strength of 128 bits. Concerns have been raised over the ability to recover the secret key if the cipher is used incorrectly.

Performance

Phelix is optimised for 32-bit platforms. The authors state that it can achieve up to eight cycles per byte on modern x86-based processors.

FPGA Hardware performance figures published in the paper "Review of stream cipher candidates from a low resource hardware perspective" are as follows:

Helix

Phelix is a slightly modified form of an earlier cipher, Helix, published in 2003 by Niels Ferguson, Doug Whiting, Bruce Schneier, John Kelsey, Stefan Lucks, and Tadayoshi Kohno; Phelix adds 128 bits to the internal state.

Helix (multimedia project)

Helix DNA is a project to produce computer software that can play audio and video media in various formats, aid in producing such media, and serve them over a network. It is intended as a largely free and open source digital media framework that runs on numerous operating systems and processors (including mobile phones) and was started by RealNetworks which contributed much of the code. The Helix Community is an open collaborative effort to develop and extend the Helix DNA platform.

Helix DNA Client is a software package for multi-platform multi-format media playback. Helix Player is a media player that runs on Linux, Solaris, Symbian and FreeBSD and uses the Helix DNA Client. The Helix DNA Producer application aids in the production of media files, and Helix DNA Server can stream media files over a network.

Licenses

The code is released in binary and source code form under various licenses, notably the proprietary RealNetworks Community Source License and the free and open source software RealNetworks Public Source License. Additionally, the Helix DNA Client and the Helix Player are licensed under the popular GNU General Public License (GPL) free and open source license.

Brainstorm

Brainstorm generally refers to brainstorming, a group or individual creativity exercise.

The term originally referred to a state of temporary insanity, gaining prominence when it was used in the defense of Harry Kendall Thaw against charges that he murdered prominent architect Stanford White.

Brainstorm may also refer to:

Film

Music

Brainstorm (album)

Brainstorm is the second album by rapper, Young MC. The album was released in 1991 for Capitol Records. After the huge success of his debut album, Stone Cold Rhymin', Young MC signed a two album deal with Capitol Records. Brainstorm did not perform as well as his previous album, only reaching No. 66 on the Billboard 200 an No. 61 on the Top R&B/Hip-Hop album charts. Though the album failed to make an impact on the charts, it nevertheless was cerified gold by the RIAA on October 9, 1991 for sales of over 500,000 copies.

Track listing

References

Brainstorm (board game)

Brainstorm is a quiz-style board game.

Brainstorm is a game for two to four players. The game uses a pile of question cards and a board. The board takes the form of a single line of squares from start to finish, and each player uses a coloured brain as his/her game counter. All counters start from the beginning square.

On each turn, the neighbour of the player in question is acting as the judge. The judge draws a question card from the pile. The question takes the form of a topic, and the player's task is to mention as many things fitting under that topic as possible, within one minute. After the time is up, the judge checks the player's answers against a checklist of ten answers on the question card. Every answer found on the checklist is worth one point. Some cards have italicised answers, these are worth two points each. The player's counter moves as many places forward as the player has scored points. Some places have special instructions to follow.

The first player to reach the finishing square wins.