Muddiest Point week 7

I was absent from class, but I once read that the internet is just a giant cable under the sea and actually incapable of handling the amount of traffic soon to be on it. How true is this?

HTML Week 8

HTML v XTML-XTML expand on HTML, XTML must be "well-formed", all formats are part of style sheet NOT IN XTML DOC

tags surrounded by <>

Attributes-pairs of standard names and values

GIF, JPEG, PNG, TIFF

Content Management System
-Content management (CM) can be defined as the process of collecting, managing and
publishing content

-content disconnected from layout and design elements
-lots of things qualify as content
-CMS rids "gatekeeper"


Commercial, open source, in-house options

Muddiest Point Metadata

How successful is DCMI?

Network Basics and Internet Week 7

Computer Network Hierarchy
-Every computer is connected to part of a network
-ISP (internet service provider)
-LAN (local area network)]
-a network of networks
-POP (point of presence)
-NAPS (network access points)

Router
-determine whether to send information
-info doesn't go where its not needed
-info makes it to intended destination

Backbones
-NSF created first one in 1987
-fiber optic trunk lines

IP Addresses
-unique identifying number
-lang. comps used to communicate over internet
-four numbers called octets

URL
-TLD:COM, .ORG, .NET, .EDU and .GOV

DNS(domain name system)
It can answer the request with an IP address because it already knows the IP address for the requested domain.
It can contact another DNS server and try to find the IP address for the name requested. It may have to do this multiple times.
It can say, "I don't know the IP address for the domain you requested, but here's the IP address for a DNS server that knows more than I do."
It can return an error message because the requested domain name is invalid or does not exist.

Muddiest Point Week 5

A reading from last week talked about how web sites are searched and subsequently dumped if they are found to have no useful information. How is such a determination made?

Metadata and Content Management

Metadata- data about data

Before 1990s metadata was used by communities who used  management and interoperability of geospatial data and with data management and systems design and maintenance in general
Meant industry standards and int and ext documentation

BIG PICTURE:
- sum total of what one can say about any information object at any level of aggregation
- information object is anything that can be addressed and manipulated as a discrete entity by a human being or an information system
-single or aggregated items or whole database

Information Objects and Three Features
1. Content- what object contains
2. Context- wwwwh
3. Structure

Library Metadata- indexes, abstracts, and bibliographic records by cataloging rules

"there is no single metadata standard that is adequate for describing all types of collections and materials; selection of the most appropriate suite of metadata standards and tools, and creation of clean, consistent metadata according to those standards, not only will enable good descriptions of specific collection materials but also will make it possible to map metadata created according to different community-specific standards,"

Structure role is becoming more important in technology age

OUTSIDE Lib
META tags in HTML for easier findings
user-created (tags)

FUNCTIONS:
-Creation, multiversioning, reuse, and recontextualization of information objects
-Organization and description
-Validation
-Search and Retrival
-Utilization and preservation
-Disposition

METADATA IS OF IMPORT AND NOT JUST DIGITAL, ITS BEEN THERE SINCE DATA HAS BEEN COLLECTED

DUBLIN CORE DATA MODEL
Dublin Core Metadata Initiative (DCMI)- international project to find some sort of consensus on metadata across disciplines

Some standards for functional requirements
-internalization
-Modularzation
-Element Identity
-Semantic Refinement
-Indetify encoding schemes
-Spec of controlled vocabs
-Inde of structured compound values

Muddiest Point Week 4

I think I'd like the relationships 1:1, 1:M ect gone over again, and what that means in terms of entities and attributes when building a database.

Database Technologies and Applications Week 5

UNION- R1+R2= R3 w/ tuples in either. Attrib must be defined on same domain

DIFFERENCE- diff of realtions R1 and R2 is new R3. Tuples only in R1

RESTRICTION- extract specified tuples from spc relation R1 by imposing cond on relationRESULT R2 has only spc tuples (replaced by selected in new systesm)

PRODUCT- R3 w/ concatenation of every tuple in R1 wit every tuple R2

PROJECTION- extract spc attri from spc R1 into new R2

JOIN- R1+R2= R3 w/ tuples R1/2 satisfy spc condition (natch)

INTERSECTION- two spc relations R1/2 where R3 has tuple in R1/2

DIVISION- relation 

PRIMARY OPERTAIONS- union, difference, select, project, adn product

SECONDARY OPERATIONS- join, intersect, divide

Aliasing-when you need to refer to different tuples in the same relations

Extend- takes realtion as input and reutrns with add column

Aggregate- summerize values of a column of realtion

SQL is ex of DSL develp in 70s

commands in command prompts of embedded applicatoins

advantages- rapid software devl, higher quality, higher productivity, data independence, standardization

Web Engines Part One

Web engines operate with large and geographically distributed centers. Clusters or ind, data centers has specific jobs, such as crawling. Large scale replication required.

CRAWLING

Speed, politeness, excluded/dupped content, spam rejection

Indexing

 inverted file to rapidly identify indexing terms

 first phase, scanning, the indexer scans the text of each input document

 for high-quality rankings, real indexers store additional information in the postings

TERM LOOKUP, COMPRESSION, PHRASES, ANCHOR TEXT,