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Lorinda Cherry
Lorinda Cherry ( Landgraf; November 18, 1944 – February 2022) was an American computer scientist and programmer. Much of her career was spent at Bell Labs, where she was for many years a member of the original Unix Lab. Cherry developed several mathematical tools and utilities for text formatting and analysis, and influenced the creation of others. Early life Cherry was born on November 18, 1944 to John F. and Evelyn K. Landgraf. She had one sister, Carynn Elizabeth. Raised in Verona, New Jersey, she graduated from Verona High School and received a Bachelor of Arts (Mathematics) from the University of Delaware in 1966. Computer science career Cherry started as a Technical Assistant (TA) at Bell Labs in 1966, initially working in Acoustics and Speech Research on vocal tract simulation. She received her Masters in computer science from Stevens Institute of Technology in 1969. At Bell Labs, Cherry was involved in projects with Ken Knowlton and James L. Flanagan related to compu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackets
A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'right' bracket or, alternatively, an "opening bracket" or "closing bracket", respectively, depending on the Writing system#Directionality, directionality of the context. Specific forms of the mark include parentheses (also called "rounded brackets"), square brackets, curly brackets (also called 'braces'), and angle brackets (also called 'chevrons'), as well as various less common pairs of symbols. As well as signifying the overall class of punctuation, the word "bracket" is commonly used to refer to a specific form of bracket, which varies from region to region. In most English-speaking countries, an unqualified word "bracket" refers to the parenthesis (round bracket); in the United States, the square bracket. Glossary of mathematical sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley (Berkeley Software Distribution, BSD), Microsoft (Xenix), Sun Microsystems (SunOS/Solaris (operating system), Solaris), Hewlett-Packard, HP/Hewlett Packard Enterprise, HPE (HP-UX), and IBM (IBM AIX, AIX). In the early 1990s, AT&T sold its rights in Unix to Novell, which then sold the UNIX trademark to The Open Group, an industry consortium founded in 1996. The Open Group allows the use of the mark for certified operating systems that comply with the Single UNIX Specification (SUS). Unix systems are chara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infix Notation
Infix notation is the notation commonly used in arithmetical and logical formulae and statements. It is characterized by the placement of operators between operands—" infixed operators"—such as the plus sign in . Usage Binary relations are often denoted by an infix symbol such as set membership ''a'' ∈ ''A'' when the set ''A'' has ''a'' for an element. In geometry, perpendicular lines ''a'' and ''b'' are denoted a \perp b \ , and in projective geometry two points ''b'' and ''c'' are in perspective when b \ \doublebarwedge \ c while they are connected by a projectivity when b \ \barwedge \ c . Infix notation is more difficult to parse by computers than prefix notation (e.g. + 2 2) or postfix notation (e.g. 2 2 +). However many programming languages use it due to its familiarity. It is more used in arithmetic, e.g. 5 × 6. Further notations Infix notation may also be distinguished from function notation, where the name of a function suggests a particular operation, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bc (programming Language)
bc, for ''basic calculator'' (often referred to as ''bench calculator''), is "''an arbitrary-precision calculator language''" with syntax similar to the C programming language. bc is typically used as either a mathematical scripting language or as an interactive mathematical shell. Overview A typical interactive usage is typing the command bc on a Unix command prompt and entering a mathematical expression, such as , whereupon will be output. While bc can work with arbitrary precision, it actually defaults to zero digits after the decimal point, so the expression yields (results are truncated, not rounded). This can surprise new bc users unaware of this fact. The option to bc sets the default ''scale'' (digits after the decimal point) to 20 and adds several additional mathematical functions to the language. History bc first appeared in Version 6 Unix in 1975. It was written by Lorinda Cherry of Bell Labs as a front end to dc, an arbitrary-precision calculator written by Rob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Polish Notation
Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators ''follow'' their operands, in contrast to Polish notation (PN), in which operators ''precede'' their operands. It does not need any parentheses as long as each operator has a fixed number of operands. The description "Polish" refers to the nationality of logician Jan Łukasiewicz, who invented Polish notation in 1924. The first computer to use postfix notation, though it long remained essentially unknown outside of Germany, was Konrad Zuse's Z3 in 1941 as well as his Z4 in 1945. The reverse Polish scheme was again proposed in 1954 by Arthur Burks, Don Warren, and Jesse Wright and was independently reinvented by Friedrich L. Bauer and Edsger W. Dijkstra in the early 1960s to reduce computer memory access and use the stack to evaluate expressions. The algorithms and notation for this scheme were extended ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbitrary-precision Arithmetic
In computer science, arbitrary-precision arithmetic, also called bignum arithmetic, multiple-precision arithmetic, or sometimes infinite-precision arithmetic, indicates that calculations are performed on numbers whose digits of precision are limited only by the available memory of the host system. This contrasts with the faster fixed-precision arithmetic found in most arithmetic logic unit (ALU) hardware, which typically offers between 8 and 64 bits of precision. Several modern programming languages have built-in support for bignums, and others have libraries available for arbitrary-precision integer and floating-point math. Rather than storing values as a fixed number of bits related to the size of the processor register, these implementations typically use variable-length arrays of digits. Arbitrary precision is used in applications where the speed of arithmetic is not a limiting factor, or where precise results with very large numbers are required. It should not be confu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dc (computer Program)
dc (''desk calculator'') is a cross-platform reverse-Polish calculator which supports arbitrary-precision arithmetic. Written by Lorinda Cherry and Robert Morris at Bell Labs, it is one of the oldest Unix utilities, preceding even the invention of the C programming language. Like other utilities of that vintage, it has a powerful set of features but terse syntax. Traditionally, the bc calculator program (with infix notation) was implemented on top of dc. This article provides some examples in an attempt to give a general flavour of the language; for a complete list of commands and syntax, one should consult the man page for one's specific implementation. History dc is the oldest surviving Unix language program. When its home Bell Labs received a PDP-11, dcwritten in Bwas the first language to run on the new computer, even before an assembler. Ken Thompson has opined that dc was the very first program written on the machine. Basic operations To multiply four and five in dc (n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brenda Baker
Brenda Sue Baker is an American computer scientist. She is known for Baker's technique for approximation algorithms on planar graphs, for her early work on duplicate code detection, and for her research on two-dimensional bin packing problems. Baker did her undergraduate studies at Radcliffe College.. She earned a Ph.D. from Harvard University in 1973; her dissertation concerned automata theory and formal languages, and was supervised by Ronald V. Book. Early in her career she was an instructor and Vinton-Hayes Research Fellow at Harvard's Division of Engineering and Applied Physics, a visiting lecturer in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley, and an assistant professor in the Department of Computer and Communication Sciences at the University of Michigan. Later she worked at Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Votrax
Votrax International, Inc. (originally the Vocal division of Federal Screw Works), or just Votrax, was a speech synthesis company located in the Detroit, Michigan area from 1971 to 1996. It began as a division of Federal Screw Works from 1971 to 1973. In 1974, it was given the ''Votrax'' name (taken from the name of its first commercial product, the model VS4 "Votrax") and moved to Troy, Michigan and, in 1980, split off of its parent company entirely and became Votrax International, Inc., which produced speech products up until 1984.Artic History 
In 1984, the company restructured itself as a commercial phone/speech audio-response/auto-answering systems c ...
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Spell (Unix)
is the standard English language spell checker for Unix, Plan 9, and Unix-like operating systems. Appearing in Version 6 Unix, was originally written by Stephen C. Johnson of Bell Labs in 1975. Douglas McIlroy later improved its accuracy, performance, and memory use, and described his work and ''spell'' in general in his 1982 paperDevelopment of a Spelling list. Spell has a simple command-line interface: It goes over all the words in a given text file, and prints a sorted list of unique misspelled words in that file. It does not provide any interface for looking for those words in the file, or helping to correct the mistakes. In 1983, a different spell-checker, (the ''interactive'' spell-checker), was ported to Unix. had a user interface for showing the spelling mistakes in context and suggesting how to correct them. Since then, the original Spell tool has been mostly considered obsolete. Another reason Spell is considered obsolete is that it only supports the English lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigram
Trigrams are a special case of the ''n''-gram, where ''n'' is 3. They are often used in natural language processing for performing statistical analysis of texts and in cryptography for control and use of ciphers and codes. Frequency Context is very important, varying analysis rankings and percentages are easily derived by drawing from different sample sizes, different authors; or different document types: poetry, science-fiction, technology documentation; and writing levels: stories for children versus adults, military orders, and recipes. Typical cryptanalytic frequency analysis finds that the 16 most common character-level trigrams in English are: Because encrypted messages sent by telegraph Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ... often omit punctuation and spaces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bigram
A bigram or digram is a sequence of two adjacent elements from a string of tokens, which are typically letters, syllables, or words. A bigram is an ''n''-gram for ''n''=2. The frequency distribution of every bigram in a string is commonly used for simple statistical analysis of text in many applications, including in computational linguistics, cryptography, speech recognition, and so on. ''Gappy bigrams'' or ''skipping bigrams'' are word pairs which allow gaps (perhaps avoiding connecting words, or allowing some simulation of dependencies, as in a dependency grammar). ''Head word bigrams'' are gappy bigrams with an explicit dependency relationship. Details Bigrams help provide the conditional probability of a token given the preceding token, when the relation of the conditional probability is applied: P(W_n, W_) = That is, the probability P() of a token W_n given the preceding token W_ is equal to the probability of their bigram, or the co-occurrence of the two tokens P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
