Unit Four: Reading Notes

Data Compression (wikipedia)
So basically, my understanding of data compression is this: a complicated process of encoding information so that it takes up less hard disk space and is less to store in general.  In the end, compressed data takes up less space because it uses fewer bits, or units of information, than an unencoded piece of information.  It might seem like I am repeating the wikipedia entry, but I'm really just trying to wrap my mind around this concept and the process of data compression.  This is all very new information for me, so I am hoping it makes a bit more sense and becomes more of a concrete concept post-lecture. One core question I have about this would be: is most data actually compressed?  What kinds of resources are needed to compress and decompress data?  Right now, this just seems like some sort of abstract concept, and something I am having difficulty understanding fully, because I really have no previous knowledge with which I can contextualize the process.

Data Compression Basics:
This article I found to be very, very helpful in understanding the ins and outs of data compression.  While some sections are a bit confusing (i.e. when the author goes into specifics about pixels and compressing data for certain colors) his likening the concept of compression to examples of this is everyday language, really helped clarify data compression significantly. An example of this would be RGB as an acronym for Red Green Blue.  Like data compression, the person reading the acronym cannot be translated into the uncompression version just using the acronym.  Like data compression, the person reading the acronym cannot translate it into its uncompressed version just by using the acronym itself.  This would make no sense. Rather, the person must match the acronym with the uncompressed version(s) in order to discern the meaning of the acronym itself. So, you have to know a little bit about what the acronym stands for, or be able to match the acronym with the origninal data to figure out the actual meaning.  These sections of this article make a lot more sense than the wikipedia article (though some parts are still unclear) because the language is much more accessible and less technical. The information on dictionary algorithms is also very clear, and the examples using the phrase "The Flying Spaghetti Monster" that uses length-distance pair (sliding window algorithm) further illustrated this concept. Lossy compression is also made clear here: the concept that we are focusing on preserving meaning, not actual data in its original form. This essentially reduces the amount of data needed to convey specific meaning.

Imaging Pittsburgh, by Edward. A Galloway:
What a great project with such potential to provide the public access to rich information.  I had heard of this initiative, but was not aware of the  depth and breadth of this project prior to reading more about it here.  What's particularly interesting and really great about the organization of the images, is just how user-friendly it appears to be.  It has been set up in such a way that keyword searches are possible, and one can also sift through the different collections according to theme, place, etc.  This at least seems to be a good example of the positive outcomes of digitizing, and the good things that can result when collections are pulled together and synthesized.  Likewise, it is easy to detect the inherent challenges that come with collaboration among such a diverse group of institutions and organizations. Identifying metadata that represents what each insitutions wants and needs is also quite perplexing.  I'd be interested in hearing more about this process specifically, because even something as seemingly simple as selecting vocaulary to use for subject headings, would quickly become a complicated discussion.

Youtube and Libraries:
I think many types of libraries have really taken advantage of the communication benefits of Youtube.  Using these kinds of Web 2.0 tools makes for a very interactive online environment for library users to enjoy and learn from, making the library an appealing and information-rich space.  An example of this would be a public library using a Flipcam to review picture books, uploading these videos, and embedding them on the library's children/youth services blogspot.  Kids and adults alike can view the videos, and maybe discover an interesting title that they'd like to check out in more depth.  Really, the potential of YouTube and other web tools to make the library an exciting, interactive, and user-friendly space is huge.

-Rachel Nard