epochとは

意味・読み方・使い方

語源

From Medieval Latin epocha, from Ancient Greek ἐποχή (epokhḗ, “a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, かつ generally the place of a star; hence, a historical epoch”), from ἐπέχω (epékhō, “I hold in, check”), from ἐπι- (epi-, “upon”) + ἔχω (ékhō, “I have, hold”).

発音

• (英国発音) IPA^(key): /ˈiːpɒk/, /ˈɛpək/
• (米国発音) IPA^(key): /ˈɛp.ək/, /ˈɛpˌɑk/, /ˈiˌpɑk/, /ˈeɪˌpɑk/
• 韻: -ɛpək, -eɪpɑk

名詞

epoch (複数形 epochs)

1. A particular period of history, or of a person's life, especially one considered noteworthy or remarkable.

   Synonyms: age, (only in general usage) era

   • 1834, Letitia Elizabeth Landon, Francesca Carrara, volume 1, page 198:

     I grew bitter in my words—I believed the worst of everyone; nay, I sometimes doubted the affection of my kind, my indulgent parents. But let me hastily pass over this vain and profitless epoch,—the fierce tempest, and the weary calm, were but the appointed means by which I reached the harbour of faith and rest.

   • 2012 January, Donald Worster, “A Drier and Hotter Future”, in American Scientist‎^[1], volume 100, number 1, page 70:

     Phoenix and Lubbock are both caught in severe drought, and it is going to get much worse. We may see many such [dust] storms in the decades ahead, along with species extinctions, radical disturbance of ecosystems, and intensified social conflict over land and water. Welcome to the Anthropocene, the epoch when humans have become a major geological and climatic force.

2. A notable event which marks the beginning of such a period.
3. (astronomy) A precise instant of time that is used as a point of reference.
4. (computing) A precise instant of time that is used as a point of reference (e.g., January 1, 1970, 00:00:00 UTC).
5. (computing) One complete presentation of the training data set to an iterative machine learning algorithm; generation.

   The neural network was trained over 500 epochs.

7. (geology) A unit of geologic time subdividing a period into smaller parts.

関連する語

• epochal
• epoche, epoché
• epochless

動詞

epoch (三人称単数 現在形 epochs, 現在分詞 epoching, 過去形および過去分詞形 epoched)

1. (sciences, transitive) To divide (data) into segments by time period.
   • 2015 July 6, “Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders”, in PLOS ONE‎^[2], DOI:10.1371/journal.pone.0132531:

     The continuous data were epoched into segments of 1500 ms (starting 500 ms before visual stimulus onset), time-locked to stimulus onset (0 ms) and sorted according to experimental conditions.