Multiscale Electrophysiology Format (MEF) was developed to handle the large amounts of data produced by large-scale
electrophysiology
Electrophysiology (from Greek , ''ēlektron'', "amber" Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , ''-logia'') is the branch of physiology that studies the electrical properties of biological cells and tissu ...
in human and animal subjects. MEF can store any time series data up to 24
bit
The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented a ...
s in length, and employs lossless range encoded
difference compression. Subject identifying information in the file header can be
encrypted
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...
using 128-bit AES encryption in order to comply with
HIPAA
The Health Insurance Portability and Accountability Act of 1996 (HIPAA or the Kennedy– Kassebaum Act) is a United States Act of Congress enacted by the 104th United States Congress and signed into law by President Bill Clinton on August 21, ...
requirements for
patient privacy when transmitting data across an open network.
Compressed data is stored in independent blocks to allow direct access to the data, facilitate parallel processing and limit the effects of potential damage to files. Data fidelity is ensured by a 32-bit cyclic redundancy check in each compressed data block using the
Koopman polynomial (0xEB31D82E), which has a
Hamming distance
In information theory, the Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. In other words, it measures the minimum number of ''substitutions'' required to chang ...
of from 4 to 114 kbits.
A formal specification and source code are available online. MEF_import
is an EEGLAB plugin to import MEF data into EEGLAB.
See also
*
Range encoding
*
AES encryption
The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001.
AES is a variant ...
*
CRC-32
MED Format official website
References
Sources
* Martin, GNN. Range encoding: an algorithm for removing redundancy from a digitised message. Video & Data Recoding Conference, Southampton, 1979.
* Koopman, P. 32-Bit Cyclic Redundancy Codes for Internet Applications. The International Conference on Dependable Systems and Networks (June 2002). 459.
* {{cite journal , last1 = Brinkmann , first1 = BH , display-authors = etal , year = 2009 , title = Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data , journal = Journal of Neuroscience Methods , volume = 180 , issue = 1, pages = 185–192 , pmc=2720128 , pmid=19427545 , doi=10.1016/j.jneumeth.2009.03.022
*
Electrophysiology
Neurophysiology
Neurotechnology
Bioinformatics
Health standards
Computer file formats