DOCSLIB.ORG

Studies in Mathematics, Volume 22. Studies in Computer Science

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Studies in Mathematics, Volume 22. Studies in Computer Science PP7 TITLE Studiei in ' Mathematics, ;lope 22. StudiOsin. SompuXerl Sciehce. INSTITUTION matheM4ical Association of(America Washington, / REPORT' NO L$BN-0-88385-12*-5 / , PUB DATE 82 NOTE 404p. / 4kVAI,LABLE FROMMathematical Association of Ame'riCi, 1529 18th St., ° 'F.' N.W.*, Washidgton, DC/20036 ($29.00). PUB TYPE'H Collected Works -_General 020 -- Viewpoin)t's 0.20) --5- Reference-Ma erials General (130) , ; EDRSPRICE.. MF01 Plus Posta el:t PC'NotAvailable from oiDRS. DESCRIPTORS ArtifiCial Intelligence; College Mathematics; *Computation; *cbmputer.Pr9grams; Computer Science; *Ccimputer Science Education; Computer Sismaation; *Data AnalysisLHighereEducation; Mathematicians; *Mathematics ducation; *Programing Languages; ' Statistics / IDENTIFIERS Mathematical/Associatlon of'America; *Numerit'al Analysis . .% ABSTRACT The nine iirticies in this collection were selected because-they represent crcerns central to computer science, emphaSize ,topics of partilculartintereSt to mathematicians, MI6 tnderscore the wide range bf areas deeply and continually. affected by computer 'science-The 5A:intents consist of: "Intioduction" (S- V. Pollack), ".The Development of Computer Science", (S. V.,Pollack), "ProgramMing Languages and Systems", (W. E. Ball), "Specifying Formal Languages" (R. V. Book), "Formal Amalysis of Computer Programs" (T., W. Pratt), "Computational Complexity" (F. P.- Preparata), "Computer Science and ArtificAal Intelligence" (a°. R. Slagle),, "The Impact of Computprs on Numerycal Analysis" (E. R. Buley and R. H. Pennington), "Compass.eSimulatipn" (M. Franklin), and "Cdmputational Tools for Statistical. Data Analysis' (C. F. .Starmer). (MRS) ****t**L************************************************************* * Reproductions supplied by EDRS are the best tha-t can be made .0. '* / . from the original document. '* **r****************************************************************** 14.S. DEPARTMENTOF EDUCATION NATIONAL INSTITUTE OF EDUCATION EDUCATIONAL RESOURCES INFORMATIO 1, CENTER (ERIC/ id This' docurrSnt has been reproducedas received from the person or organization, originating It Minor chahges have been da to improve reproductiop, quality. Points of iimiv or opiniohs stated in'thisdocu- ment do,not necessarily represent officialNIE,, position or policy?' j'PERMISSION REPRODUCE YHI MATERIAL IN MICROF CHE-1NLY- HAS BEEN GRANTE BY - d 43. 10,1111641 TO THE EDUCATIONAL L IRESOLIRCES _INFORMATION CE TEP(ERICV: _ y MAOA' ST:UDI,ES IN. 'MATHEMATICS b . Publi;lit4 by THEMATHEMATICAL ASSOCIATION OF AMERICA Coinmitiee.on Publications E. F. BECKENBACH, Chairman - 7 Subcommittei.'-op M AA Softiies-in MpthematG G. 'L.. WEISS; Chairman D.' W.. ANDERSON A. C. TUCKER _ ; Studies in Mathematics TheMathematical Association Of America VOIURIC 1: STUDIES IN MODERN ANALYSIS edited by R. C. Buck Volume 2:STUDIES IN MODERN ALGEBRA edited by A. A. Albert Volume 3:STUDIES IN REAL 4D COMPLEX ANALYSIS edited by I. I. Hirschtnah, Jr. Volume 4:STUDIES IN GLOBAL GEOMETRY AND ANALYSIS edited by S. S. Chern 'Volume 5: STUDIES IN MODERN TOPOLOGY ediled by P.J. Hilton Volume -6:STUDIES IN N'CIMBFIR THEORY edited by W. J. LeVegue Volume 7:STUDIES IN APPLIED MATHEMATICS edited by A. H. Taub ,,Q. vumeol 8:STUDIES IN MODEL THEORY edited by M. D.Aforley V dlunie9: STUDIES IN ALGEBRAIC.' LOGIC Wiled by Aubert Daigneault Volume 10:STUDIES IN OPTIMIZATION edited by G. B. Dantzig and B: G. Eaves Volume 11:STUDIES IN GRAPH THEORY, PART I ° edited by D.. R.(Fulkerson Volume 12:STUDIES IN GRAPH THEORY,,PART 11 edited -D.R.Ettficerson Volume 13: sTuplEs INHARMONIC ANALYSIS edited by J. M. Ash Volume14:STUDIES,,IN ORDINARY DIFFERENTIAL EQUATIONS,_ edited by Jack !foie Volume 15;STUDIES IN MATHEMATICAL BIOLOGY, PART I edited by S. A. Levin Volume 16;STUDIES IN MATHEMATICAL BIOLOGY, PART II , edited by S.(A: Levin Voldne 17: STUDIES IN COMBINATORICS 0, edited by G.-C. Rota Voliime`0:STUDIES IN PROBABILITY THEORY edited by Murray, Rose Volume .19:STUDIES IN STATISTICS edited by R. V. Hogg Volume 20:-STUDIES IN ALGEBRAIC GEOMETRY edited by A. Seidenberg Voluble21:STUDIES IN FUNCTIONAL ANALYST edited by R. G. Bartle? "' Volume 22:STUDIES IN COMPUTER SCIENCE edited by S. V. Pollack v; William E. Ball , Washington University in St. Louis Ronald V. Rook' Univevityof California at SantaBarbartet,. ;E. R. Bulfr, General Research Corporation, Santa Barbara Mark, Franklin Washington. University in St. Louis R. if. Pennington General Research Vorporation, Santa Barbara r. Seyittour.V. Pollack ifaShingtonijniver.sitY in- St. Louis Terence W. Pratt Unityrsity of Virginiit Franco P. Preparata University of Illinois,rban*hatupaigti.- James R. Slagle Navel Research llabor ry, Washington, D.C: sA C. F. Stariner Duke University -.7.- Washington: ljniuer'S'ityirt.$(.:i.VOui; :* to- Published and distributeddistributed by The MathematicalAsociati6jnof America CO 1982 by , TheMathematicallissociation of America (incorporated) Library of Congress Catttiog CardNumber82-062390 - - - _ _ _ CornpleteSet ISBN 0-88385-1004 Vol, 22 ISBN 0- 88385 -1244 Printed in the Unita Sttes-of America Current printing(last digit): 109.8 7 6 5.4 3 2 I 4NTRODUCT1011 The AssOciation of Computing Michindy'S Administrative Di- rectory for 1979 lists 207 American computer science departments granting bachelor's degrees, 127 granting master's degrees, and ,73 offering Ph.D. oi D.Sc. degrees. In addition, the,directqrr includes computer science programs at all levels embedded in 163 math- ematics departments, 56 busines3 schools, 29 electrical engineering departments, and 40 other schools_or departments, including such diverse, areas as physics, industrial kengineering, and economics. What makes these figures remarkable is the fact that the first coin- piiter science departMent appeared less than-two decades-earlier: To me, this rapid grpwth is but one of several, factors that combine, to place computer science in an exceptional position vii-a,vis other areas of inquiry:A-brief exploration of these points will be helpful 'in providing some general perspectiv4 within which the articles in this study can be considered( important to, note that_ the burgeoning of coinp,uter First, it _ science programs cannot be equaiedwiththif inatbFatioircif-coni= puler .science..There Aill is no "sraildard" (i.e., universally inoffen- sive) definition al computer science, In fact, the existence of such a The cyclopedia of Computer Science (A.Ralston and C Meek, eds., Pet- rocelli/Charter, 1976) defines computer science as follows: "Computer science is \viii Seymour V. Pollack \ ., discipline continues to, be a debatable point for a substantillo nuMber 4, people. (A prominent educator, though himself it cl)airman of a computer science department, cautions his audiences to, regard with suspicion any discipline with "science" in its name urban \$tibnce, consumer scicncc, economic science, social science, .-- computer Sortie people think of computer science's "uni- verse" as\a relatively restricted one, limited by definition to elm= tronic .digital information processing ,,systcms. Definitions at the othcr end o4 the spectrum perceive an arena consisting of an arbi- trarily wide range of information processing systems, ineluding..bio. logical ones. .Despite this diversity, thc digital cOmputer system is clearly the dom'nant vehicle for study. Mildly staked, this is a very unusual gituatio :Instead of. exploring the behavior of a cell,' a fluid,ean Organis or a galaxy, the computer scientist seeks basic observable phenomena from an artifact (i.e., the cornputcr itself or' the program procesAtherein). Thus*,the quest cor"`natural rayvs7 carries little meaning\ here. There is no ultimate and final reality against which e natory structures are to be assessed. The \ "reality," .represente ardwarc, Software, and informations is arbitrarilX alterable.hough it may sound almost facetiojis, the fact remains that, if an attempt (regardless of its degree of formalism) falls ihRrt of explaining observed events, those events (i.e., reality) can be c anged'to meet the explanationalf- way. Inevitably, this has a pr ound effect on the phenomena com- puter scientists seek to descriNand the ways in which such de- scriptions are voiced. A second major peculiarity lies in-computer science's-inherent, invisibility. End products Of comp terscienCe,4:e., information pro- cessing systerns, generally are used and mbtivated) by people with -little° interegt in computer. science. \A major objective in the im- plementation of such produ s', is to obscure their inner workings so .,.. , i ..t that the user's attention r mains focUsed on the externally per ceived behavior. For instance, a well-designed translating system ford high=level -programming language (su\ ch at-FORTRAN) sue . ' i` 4 .. \ concerned' with information processes, with the informatio4 structures and pro- o. cedures that enter into representations of such processes\and with their implemen- tation and ihform tion proce&sing systems. It is also concerned with relationships between informatioi processes and classes oftasks that givefse'io them." .,. ......_./ 1" \ 1. INTRODUCTION .IX cesifully promotes the illusion that 'the user's prbgrams execute directly on a FORTRAN computer, with no apparent 'intervention bctwccn the program (as .written) and the machinery. (This is cm- ,. phasized by the jargon, which terms such a'system "transparent" to its users.) -Conversely, implementors of such systems generhily are less concerned with the ultimate uses than they are with the tcchni- cal issues
Load more

Recommended publications
  • Hardware Pattern Matching for Network Traffic Analysis in Gigabit
    Technische Universitat¨ Munchen¨ Fakultat¨ fur¨ Informatik Diplomarbeit in Informatik Hardware Pattern Matching for Network Traffic Analysis in Gigabit Environments Gregor M. Maier Aufgabenstellerin: Prof. Anja Feldmann, Ph. D. Betreuerin: Prof. Anja Feldmann, Ph. D. Abgabedatum: 15. Mai 2007 Ich versichere, dass ich diese Diplomarbeit selbst¨andig verfasst und nur die angegebe- nen Quellen und Hilfsmittel verwendet habe. Datum Gregor M. Maier Abstract Pattern Matching is an important task in various applica- tions, including network traffic analysis and intrusion detec- tion. In modern high speed gigabit networks it becomes un- feasible to search for patterns using pure software implemen- tations, due to the amount of data that must be searched. Furthermore applications employing pattern matching often need to search for several patterns at the same time. In this thesis we explore the possibilities of using FPGAs for hardware pattern matching. We analyze the applicability of various pattern matching algorithms for hardware imple- mentation and implement a Rabin-Karp and an approximate pattern matching algorithm in Endace’s network measure- ment cards using VHDL. The implementations are evalu- ated and compared to pure software matching solutions. To demonstrate the power of hardware pattern matching, an example application for traffic accounting using hardware pattern matching is presented as a proof-of-concept. Since some systems like network intrusion detection systems an- alyze reassembled TCP streams, possibilities for hardware TCP reassembly combined with hardware pattern matching are discussed as well. Contents vii Contents List of Figures ix 1 Introduction 1 1.1 Motivation . 1 1.2 Related Work . 2 1.3 About Endace DAG Network Monitoring Cards .
    [Show full text]
  • Comprehensive Examinations in Computer Science 1872 - 1878
    COMPREHENSIVE EXAMINATIONS IN COMPUTER SCIENCE 1872 - 1878 edited by Frank M. Liang STAN-CS-78-677 NOVEMBER 1078 (second Printing, August 1979) COMPUTER SCIENCE DEPARTMENT School of Humanities and Sciences STANFORD UNIVERSITY COMPUTER SC l ENCE COMPREHENSIVE EXAMINATIONS 1972 - 1978 b Y the faculty and students of the Stanford University Computer Science Department edited by Frank M. Liang Abstract Since Spring 1972, the Stanford Computer Science Department has periodically given a "comprehensive examination" as one of the qualifying exams for graduate students. Such exams generally have consisted of a six-hour written test followed by a several-day programming problem. Their intent is to make it possible to assess whether a student is sufficiently prepared in all the important aspects of computer science. This report presents the examination questions from thirteen comprehensive examinations, along with their solutions. The preparation of this report has been supported in part by NSF grant MCS 77-23738 and in part by IBM Corporation. Foreword This report probably contains as much concentrated computer science per page as any document In existence - it is the result of thousands of person-hours of creative work by the entire staff of Stanford's Computer Science Department, together with dozens of h~ghly-talented students who also helped to compose the questions. Many of these questions have never before been published. Thus I think every person interested in computer science will find it stimulating and helpful to study these pages. Of course, the material is so concentrated it is best not taken in one gulp; perhaps the wisest policy would be to keep a copy on hand in the bathroom at all times, for those occasional moments when inspirational reading is desirable.
    [Show full text]
  • Trusted Research Environments (TRE) a Strategy to Build Public Trust and Meet Changing Health Data Science Needs
    Trusted Research Environments (TRE) A strategy to build public trust and meet changing health data science needs Green Paper v2.0 dated 21 July 2020 – For sign off Table of Contents Executive Summary .................................................................................................................................................... 3 Status of the document .............................................................................................................................................. 5 Overview .................................................................................................................................................................... 6 Purpose ........................................................................................................................................................................... 6 Background .................................................................................................................................................................... 6 The case for TREs providing access to health data through safe settings ...................................................................... 8 Requirements for a Trusted Research Environment...................................................................................................10 Safe people ................................................................................................................................................................... 10 Safe projects ................................................................................................................................................................
    [Show full text]
  • A Personalized Cloud-Based Traffic Redundancy Elimination for Smartphones Vivekgautham Soundararaj Clemson University, [email protected]
    Clemson University TigerPrints All Theses Theses 5-2016 TailoredRE: A Personalized Cloud-based Traffic Redundancy Elimination for Smartphones Vivekgautham Soundararaj Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Recommended Citation Soundararaj, Vivekgautham, "TailoredRE: A Personalized Cloud-based Traffic Redundancy Elimination for Smartphones" (2016). All Theses. 2387. https://tigerprints.clemson.edu/all_theses/2387 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. TailoredRE: A Personalized Cloud-based Traffic Redundancy Elimination for Smartphones A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Computer Engineering by Vivekgautham Soundararaj May 2016 Accepted by: Dr. Haiying Shen, Committee Chair Dr. Rong Ge Dr. Walter Ligon Abstract The exceptional rise in usages of mobile devices such as smartphones and tablets has contributed to a massive increase in wireless network traffic both Cellular (3G/4G/LTE) and WiFi. The unprecedented growth in wireless network traffic not only strain the battery of the mobile devices but also bogs down the last-hop wireless access links. Interestingly, a significant part of this data traffic exhibits high level of redundancy in them due to re- peated access of popular contents in the web. Hence, a good amount of research both in academia and in industries has studied, analyzed and designed diverse systems that attempt to eliminate redundancy in the network traffic.
    [Show full text]
  • Branchclust Tutorial
    BranchClust A Phylogenetic Algorithm for Selecting Gene Families Version 1.01 Tutorial http://www.bioinformatics.org/branchclust Copyright © Maria Poptsova and J. Peter Gogarten 2006-2007 Tutorial Selection of orthologous families with BranchClust is a multi-stage process that includes processing BLAST results, assembling superfamilies, alignment, reconstruction of phylogenetic trees, and applying the BranchClust method itself. Here we describe step-by- step procedures used for selection of orthologous families for a set of different taxa. All perl scripts described here are freely available and can be downloaded as one archive from the web-site: http://www.bioinformatics.org/branchclust/ All following procedures could be divided into 6 major stages: I. Downloading complete genomes and collection of significant hits II. Creation of taxa identification table III. Assemblage of superfamilies IV. Reconstruction of superfamily trees. V. Selection of orthologous families with BranchClust VI. Visualization of results with TreeDyn For all the programs described below, it is assumed that they are run from inside one directory. Perl-scripts create output files that are further used as input by other programs so that each step should be performed in order described in the tutorial. The scripts and programs were tested under both Mac OSX Darwin and Debian Linux operating sytems. Modules or standalone programs such as BioPerl, blastall, clustalw and treedyn need to be installed in the system. These programs are available from BioPerl – http://www.bioperl.org Blastall - http://www.ncbi.nlm.nih.gov/BLAST/download.shtml Clustalw - http://bips.u-strasbg.fr/fr/Documentation/ClustalX/ TreeDyn - http://www.treedyn.org I. Downloading complete genomes and collection of significant hits 1.
    [Show full text]
  • Approximate Pattern Matching with Index Structures
    Technische Universität München Fakultät für Informatik Lehrstuhl für Effiziente Algorithmen a Approximatec e Pattern Matching b with Index Structuresd f Johannes Krugel a c b d c e d f e e e f a d e b c f Technische Universität München Fakultät für Informatik Lehrstuhl für Effiziente Algorithmen Approximate Pattern Matching with Index Structures Johannes A. Krugel Vollständiger Abdruck der von der Fakultät für Informatik der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. Helmut Seidl Prüfer der Dissertation: 1. Univ.-Prof. Dr. Ernst W. Mayr 2. Univ.-Prof. Dr. Stefan Kramer, Johannes Gutenberg-Universität Mainz Die Dissertation wurde am 06.05.2015 bei der Technischen Universität München eingereicht und durch die Fakultät für Informatik am 19.01.2016 angenommen. ii Zusammenfassung Ziel dieser Arbeit ist es, einen Überblick über das praktische Verhalten von Indexstrukturen und Algorithmen zur approximativen Textsuche (approximate pattern matching, APM) zu geben, abhängig von den Eigenschaften der Eingabe. APM ist die Suche nach Zeichenfolgen in Texten oder biologischen Sequenzen unter Berücksichtigung von Fehlern (wie z. B. Rechtschreibfehlern oder genetischen Mutationen). In der Offline-Variante dieses Problems kann der Text vorverarbeitet werden, um eine Indexstruktur aufzubauen bevor die Suchanfragen beantwortet werden. Diese Arbeit beschreibt und diskutiert praktisch relevante Indexstrukturen, Ähnlichkeitsmaÿe und Suchalgorithmen für APM. Wir schlagen einen neuen effizienten Suchalgorithmus für Suffixbäume im externen Speicher vor. Im Rahmen der Arbeit wurden mehrere Indexstrukturen und Algorithmen für APM implementiert und in einer Softwarebibliothek bereitgestellt; die Implementierungen sind effizient, stabil, generisch, getestet und online verfügbar.
    [Show full text]
  • How to Think Like a Computer Scientist
    How to Think Like a Computer Scientist Logo Version ii How to Think Like a Computer Scientist Logo Version Allen B. Downey Guido Gay Version 1.0 October 30, 2003 Copyright °c 2003 Allen B. Downey, Guido Gay. History: March 6, 2003: Allen B. Downey, How to Think Like a Computer Scientist. Java Version, fourth edition. October 30, 2003: Allen B. Downey, Guido Gay, How to Think Like a Com- puter Scientist. Logo Version, first edition. Permission is granted to copy, distribute, and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later ver- sion published by the Free Software Foundation; with Invariant Sections being “Preface”, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the appendix entitled “GNU Free Documentation License.” The GNU Free Documentation License is available from www.gnu.org or by writing to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. The original form of this book is LATEX source code. Compiling this LATEX source has the effect of generating a device-independent representation of the book, which can be converted to other formats and printed. The LATEX source for this book is available from http://ibiblio.org/obp/thinkCS/ Prefazione Logo is a programming language mostly used as a teaching tool in primary education. If you know about its turtle graphics commands — such as repeat 10 [repeat 5 [fd 30 lt 72] lt 36] — you may be curious about its other capabilities.
    [Show full text]
  • A Best-First Anagram Hashing Filter for Approximate String Matching
    A best-first anagram hashing filter for approximate string matching with generalized edit distance Malin AHLBERG Gerlof BOUMA Språkbanken / Department of Swedish University of Gothenburg [email protected], [email protected] ABSTRACT This paper presents an efficient method for approximate string matching against a lexicon. We define a filter that for each source word selects a small set of target lexical entries, from which the best match is then selected using generalized edit distance, where edit operations can be assigned an arbitrary weight. The filter combines a specialized hash function with best-first search. Our work extends and improves upon a previously proposed hash-based filter, developed for matching with uniform-weight edit distance. We evaluate an approximate matching system implemented with the new best-first filter, by conducting several experiments on a historical corpus and a set of weighted rules taken from the literature. We present running times and discuss how performance varies using different stopping criteria and target lexica. The results show that the filter is suitable for large rule sets and million word corpora, and encourage further development. KEYWORDS: Approximate string matching, generalized edit distance, anagram hash, spelling variation, historical corpora. Proceedings of COLING 2012: Posters, pages 13–22, COLING 2012, Mumbai, December 2012. 13 1 Introduction A common task in text processing is to match tokens in running text to a dictionary, for instance to see if we recognize a token as an existing word or to retrieve further information about the token, like part-of-speech or distributional statistics. Such matching may be approximate: the dictionary entry that we are looking for might use a slightly different spelling than the token at hand.
    [Show full text]
  • The Answer Question in Question Answering Systems Engenharia
    The Answer Question in Question Answering Systems Andr´eFilipe Esteves Gon¸calves Disserta¸c~aopara obten¸c~aodo Grau de Mestre em Engenharia Inform´aticae de Computadores J´uri Presidente: Prof. Jos´eManuel Nunes Salvador Tribolet Orientador: Profa Maria Lu´ısaTorres Ribeiro Marques da Silva Coheur Vogal: Prof. Bruno Emanuel da Gra¸caMartins Novembro 2011 Acknowledgements I am extremely thankful to my Supervisor, Prof. Lu´ısaCoheur and also my colleague Ana Cristina Mendes (who pratically became my Co-Supervisor) for all their support throughout this journey. I could not have written this thesis without them, truly. I dedicate this to everyone that has inspired me and motivates me on a daily basis over the past year (or years) { i.e. my close friends, my chosen family. It was worthy. Thank you, you are my heroes. Resumo No mundo atual, os Sistemas de Pergunta Resposta tornaram-se uma resposta v´alidapara o problema da explos~aode informa¸c~aoda Web, uma vez que con- seguem efetivamente compactar a informa¸c~aoque estamos `aprocura numa ´unica resposta. Para esse efeito, um novo Sistema de Pergunta Resposta foi criado: Just.Ask. Apesar do Just.Ask j´aestar completamente operacional e a dar respostas corretas a um certo n´umerode quest~oes,permanecem ainda v´ariosproblemas a endere¸car. Um deles ´ea identifica¸c~aoerr´oneade respostas a n´ıvel de extra¸c~ao e clustering, que pode levar a que uma resposta errada seja retornada pelo sistema. Este trabalho lida com esta problem´atica,e ´ecomposto pelas seguintes tare- fas: a) criar corpora para melhor avaliar o sistema e o seu m´odulode respostas; b) apresentar os resultados iniciais do Just.Ask, com especial foco para o seu m´odulode respostas; c) efetuar um estudo do estado da arte em rela¸c~oesen- tre respostas e identifica¸c~aode par´afrases de modo a melhorar a extra¸c~aodas respostas do Just.Ask; d) analizar erros e detectar padr~oesde erros no mdulo de extra¸c~aode respostas do sistema; e) apresentar e implementar uma solu¸c~ao para os problemas detectados.
    [Show full text]
  • Comparing Namedcapture with Other R Packages for Regular Expressions by Toby Dylan Hocking
    CONTRIBUTED RESEARCH ARTICLE 328 Comparing namedCapture with other R packages for regular expressions by Toby Dylan Hocking Abstract Regular expressions are powerful tools for manipulating non-tabular textual data. For many tasks (visualization, machine learning, etc), tables of numbers must be extracted from such data before processing by other R functions. We present the R package namedCapture, which facilitates such tasks by providing a new user-friendly syntax for defining regular expressions in R code. We begin by describing the history of regular expressions and their usage in R. We then describe the new features of the namedCapture package, and provide detailed comparisons with related R packages (rex, stringr, stringi, tidyr, rematch2, re2r). Introduction Today regular expression libraries are powerful and widespread tools for text processing. A regular expression pattern is typically a character string that defines a set of possible matches in some other subject strings. For example the pattern o+ matches one or more lower-case o characters; it would match the last two characters in the subject foo, and it would not match in the subject bar. The focus of this article is regular expressions with capture groups, which are used to extract subject substrings. Capture groups are typically defined using parentheses. For example, the pattern [0-9]+ matches one or more digits (e.g. 123 but not abc), and the pattern [0-9]+-[0-9]+ matches a range of integers (e.g. 9-5). The pattern ([0-9]+)-([0-9]+) will perform matching identically, but provides access by number/index to the strings matched by the capturing sub-patterns enclosed in parentheses (group 1 matches 9, group 2 matches 5).
    [Show full text]
  • The Power of Prediction: Cloud Bandwidth and Cost Reduction
    The Power of Prediction: Cloud Bandwidth and Cost Reduction ∗ † Eyal Zohar Israel Cidon Osnat (Ossi) Mokryn Technion - Israel Institute of Technion - Israel Institute of Tel Aviv Academic College Technology Technology [email protected] [email protected] [email protected] ABSTRACT 1. INTRODUCTION In this paper we present PACK (Predictive ACKs), a novel end-to- Cloud computing offers its customers an economical and con- end Traffic Redundancy Elimination (TRE) system, designed for venient pay as you go service model, known also as usage-based cloud computing customers. pricing [6]. Cloud customers1 pay only for the actual use of com- Cloud-based TRE needs to apply a judicious use of cloud re- puting resources, storage and bandwidth, according to their chang- sources so that the bandwidth cost reduction combined with the ad- ing needs, utilizing the cloud’s scalable and elastic computational ditional cost of TRE computation and storage would be optimized. capabilities. Consequently, cloud customers, applying a judicious PACK’s main advantage is its capability of offloading the cloud- use of the cloud’s resources, are motivated to use various traffic re- server TRE effort to end-clients, thus minimizing the processing duction techniques, in particular Traffic Redundancy Elimination costs induced by the TRE algorithm. (TRE), for reducing bandwidth costs. Unlike previous solutions, PACK does not require the server to Traffic redundancy stems from common end-users’ activities, continuously maintain clients’ status. This makes PACK very suit- such as repeatedly accessing, downloading, distributing and modi- able for pervasive computation environments that combine client fying the same or similar information items (documents, data, web mobility and server migration to maintain cloud elasticity.
    [Show full text]
  • Necessary to Conduct Most Analyses Commercial Software Typically Have (Very Bad) Installers Open Source Software Typically Have
    installing software necessary to conduct most analyses commercial software typically have (very bad) installers open source software typically have (bad) installers often (very) poorly documented tested on a limited number of configurations use the tested configuration if yours doesnt work dependencies are not always listed or ambiguously listed one of the most frustrating things about POSIX package managers installs executable (usually binary) and configuration files greatly simplifies installation and upgrades depends upon the (usually volunteer) package maintainers apt the Debian wrapper for dpkg used to install, update, remove, and purge packages will install dependencies for the target package http://packages.ubuntu.com/ if apt fails, try aptitude (the industrial strength version) apt sudo atp update updates the package cache sudo atp upgrade installs most upgrades sudo atp autoremove removes unneeded packages apt-cache search x searches repository for x apt-cache show x information for package x sudo apt install x installs package x sudo apt remove x removes package x sudo apt purge x removes package x and its files apt general use sudo atp update sudo atp upgrade sudo apt install scripts (interpreted code) simple scripts are placed in a directory listed in $PATH e.g. $HOME/bin dependencies must be satisfied interpreter interpreter extensions external programs environmental variables some interpreters (e.g. Perl, Python, JavaScript) have their own package management systems compiling… convert source code (text) into a (binary) executable file ./configure script that produces an appropriate MakeFile not required for all programs should indicate missing dependencies can set various options specify the (non–standard) location of a dependency set program specific options e.g.
    [Show full text]