Week Three:

REQUIRED READING NOTES

Data Compression (Wikipedia)

• Involves encoding information using fewer bits than the original representation. Also known as data compression, source-coding, or bit-reduction. Proves useful because it helps reduce data storage space or transmission capacity.
• this is the process of reducing the size of a data file
• bits - defined as the basic unit of information in computing and digital communication.
• Two major types of compression: Lossy and Lossless
• Lossy -  most commonly used to compress multimedia data (audio, video, and still images), and most especially in applications that stream media.
• Lossless - used in many applications such as ZIP file formats, text documents, image file formats, and source codes. Most commonly used for archiving or production purpose.
•  Compressed data must be decompressed to use. It is subject to a space-time complexity trade (algorithm)

Data Compression Basics (DVD-HQ)
http://dvd-hq.info/data_compression_1.php#Comparison

• Article on data-compression with a focus on media (images, audio and video). 
• Advantage of data compression is the allowance of storing more data in one space while also allowing you to transfer the space in less time with less bandwidth.
• Idea behind Data Compression is to take a given representation of information and replace with a new representation that takes up less space.
• lossless data retrieves exactly identical information from the original source
• lossy data retrieves information that is not guaranteed to be exactly identical.
•  Run-length encoding replaces a sequence of identical characters with one single character, followed by number of characters in the sentence. It has an advantage of being simple and fast to execute.Very important for image data (BMP, PCX)
• Discussion on algorithms such as the Lempel-Ziv compressor
• Entropy coding, encoding, is a technique that assigns codes to blocks of data (symbols) in such a way that the length of the code is inversely proportional to the statistical probability of the symbol.
• it assigns shorter codes to common data blocks while assigning longer coeds to rarer data blocks
• Huffman coding - generates codes that a code for one symbol is never identical to the start of another code.
• eliminates the need for a special marker, relatively simple and quick. popular

 

"Imaging Pittsburgh: Creating a shared gateway to digital image collections of the Pittsburgh region"
by Edward A. Galloway
http://firstmonday.org/ojs/index.php/fm/article/view/1141/1061

• Paper focuses on the 2002 National Leadership Grant from the Institute of Museum and Library Services awarded to the University of Pittsburgh
• proposed to create a shared gateway to visual image collections in Pittsburgh regions.
• focused on the Archives Service Center at Pitt, the Library & Archives division of the Historical Society of Western Pennsylvania, and the Carnegie Museum of Art.
• grant began on November 1, 2002 and was completed on October 31, 2004.
•  Focus was to create a single web gateway for public access to thousands of visual images from the photographic collections held by the Archives Service Center of Pittsburgh University.
• partners were responsible for selecting images and determining which collections to represent
• Benefits for users working with the collection:
• ability to obtain wider picture of events and people as well as localities, infrastructure, and land use.
• important because of the different perspectives of the city throughout time
• Web gateway was able to be accessed through keyword searches, browsing images, exploration of collections, and order of image reproductions
•  Dated article - april 2004

"Youtube and libraries: It could be a beautiful relationship" by Paula L. Webb
http://crln.acrl.org/content/68/6/354.full.pdf

• Dated June 2007, this article examines the possible relationship between YouTube and libraries, noting that YouTube at this time is one of the most popular internet sites and utilizing it as a librarian can entice patrons with information about said library.
• Can be used as storehouses for instructional videos
• used as a method of introducing resources that are available on campus
• create tutorials to teach students how to use databases and software

Thoughts 

The recommended readings for this week are very heavily focused on information on compressed data. We see with the Wikipedia article and the very helpful tutorial that data compression is a very involved field, but as information specialists we are faced with using them every day. The manual was very helpful and explained a lot of information in a language that I understood. The two final articles that focus on photo collections and YouTube as a tool for advocacy were interesting to me as a student and a patron. I briefly browsed the University's Archives Center website for the LIS2000 class (my group was researching special collections in state archives). It was extremely accessible and much better suited for our technological advances since 2004.

Questions
 

1. How do librarians and information specialists use the processing of encoding and data compression? Where does these fields come into play for students and faculty as well?
2. Does YouTube actually offer patrons of libraries extra information, or has this role been taken over by Facebook and Twitter?