The Open eXchange Data Format, or OpenXDF, is an open,

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

-based standard for the digital storage and exchange of time-series physiological signals and metadata. OpenXDF primarily focuses on

electroencephalography Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...

and

polysomnography Polysomnography (PSG), a type of sleep study, is a multi-parameter study of sleep and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Gree ...

History

Neurotronics began work on OpenXDF in 2003 with the goal of providing a modern, open, and extensible file format with which clinicians and researchers can share physiological data and metadata, such as signal data, signal montages, patient demographics, and event logs. Neurotronics released the first draft of the OpenXDF Specification just before the 18th meeting of the

Associated Professional Sleep Societies Associated may refer to: *Associated, former name of Avon, Contra Costa County, California * Associated Hebrew Schools of Toronto, a school in Canada *Associated Newspapers, former name of DMG Media, a British publishing company See also *Associati ...

in 2004. Neurotronics has since relinquished control of the format to the OpenXDF Consortium. As of version 1.0, OpenXDF is 100% backward compatible with the European Data Format (EDF), the current de facto standard format for physiological data exchange.

Features

Tiered structure

OpenXDF is a tiered framework designed to allow standardized and custom specializations of the format while enforcing a common foundation that provides a high-level of compatibility between unrelated systems.

Metadata

OpenXDF expands on EDF by providing standardized support for extensive patient information, display montages, annotations, and scoring information.

Unicode support

OpenXDF requires the use of a XML 1.0 compliant parser that supports

UTF-8 UTF-8 is a variable-width encoding, variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit'' ...

and

UTF-16 UTF-16 (16-bit computing, 16-bit Unicode Transformation Format) is a character encoding capable of encoding all 1,112,064 valid code points of Unicode (in fact this number of code points is dictated by the design of UTF-16). The encoding is variab ...

Signal configuration

OpenXDF supports fully and independently configurable data signals. Each signal specifies its byte order, whether its samples are signed, the size of its samples, and its sampling rate.

Security

OpenXDF supports encryption of the XML file using

TwoFish In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. It was one of the five finalists of the Advanced Encryption Standard contest, but it was not selected for standardization. Twof ...

in Cipher Feedback (CFB) mode with a 256-bit key created from a UTF-8 encoded password hashed with

SHA-256 SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression ...

. In addition, OpenXDF supports integrity verification using a

SHA-512 SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression ...

hash of the original XML file.

References

OpenXDF Web SiteOpenXDF Specification

External links

European Data Format (EDF) Specifications
{{DEFAULTSORT:Openxdf Electroencephalography Industry-specific XML-based standards