A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session7prm78q4i2rgket26a22i0q4k2aob319): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests

Filename: helpers/my_audit_helper.php

Line Number: 197

Backtrace:

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 197
Function: file_get_contents

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 271
Function: simplexml_load_file_from_url

File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3145
Function: getPubMedXML

File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global

File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword

File: /var/www/html/index.php
Line: 316
Function: require_once

Chord keyboards. | LitMetric

Chord keyboards.

Appl Ergon

HUSAT Research Group, Loughborough University of Technology.

Published: March 1983

Unlike the standard typewriter keyboard, keying on a chord keyboard is carried out by simultaneous patterned pressing of one or more keys. This results in fewer keys being needed on a chord keyboard when compared with a sequential keyboard, where keys are pressed one at a time. For example, five keys allow a total of 31 (2(5) - 1) different chord combinations to be generated. The feasibility of using a chord keyboard as a data entry input device was first seriously investigated in the mid-1950s by the Canadian Post Office. The trend towards research into chord keying reached a peak around 1960 when International Business Machines (IBM) studied two chord keyboards to rival the typewriter. It was not until the 1970s that chord keyboards became commercially available and within the last decade three chord keying devices have been marketed. The emphasis on the development of these recent keyboards has moved from task specific to more general purpose applications. This paper (based upon Martin (1980) the author's maiden name) reviews the chord keyboards which have been developed since the 1940s with special emphasis on the mail sorting application, and draws some conclusions concerning future developments.

Download full-text PDF

Source
http://dx.doi.org/10.1016/0003-6870(83)90221-1DOI Listing

Publication Analysis

Top Keywords

chord keyboards
16
chord keyboard
12
chord
10
chord keying
8
keyboard
5
keyboards standard
4
standard typewriter
4
typewriter keyboard
4
keyboard keying
4
keying chord
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!