A policy concern in the information age is the “digital divide,” a gap between those who have easy access to technology and those who do not. References are made to information “haves” and “have-nots” in an age where information is equivalent to wealth (Holloway, 2000). The “have-nots” are in danger of exclusion from the new economy and marginalization into low-wage jobs (Dunham, 1999). In 2000, the President of the United States asked the IT community to help close this digital divide for moral reasons and to ensure that the economy flourishes with the availability of skilled workers (Shewmake, 2000). This overview summarizes a five-phase service-learning project accomplished through a partnership between the University of Toledo and a local K-8 parochial/non-profit school. The students were primarily enrolled in a Systems Analysis, Design and Implementation course (SAD). This longitudinal project was undertaken to plan, design, and wire a network for the school and to assess and implement continuing and future computer needs. It allowed students to gain “real-life” experience while contributing to the growth of IT among children in a non-profit setting.
Mature engineering disciplines are generally characterized by accepted methodical standards for describing all relevant artifacts of their subject matter. Such standards not only enable practitioners to collaborate, but they also contribute to the development of the whole discipline. In 1994, Grady Booch, Jim Rumbaugh, and Ivar Jacobson joined together to unify the plethora of existing object-oriented systems engineering approaches at semantic and notation level (Booch, 2002; Fowler, 2004; Rumbaugh, Jacobson & Booch, 1998). Their effort leads to the unified modeling language (UML), a well-known, general-purpose, tool-supported, process-independent, and industry-standardized modeling language for visualizing, describing, specifying, and documenting systems artifacts.
UML is applicable to software and non-software domains, including software architecture (Medvidovic, Rosenblum, Redmiles, & Robbins, 2002), real-time and embedded systems (Douglass, 2004), business applications (Eriksson & Penker, 2000), manufacturing systems (Bruccoleri, Dieaga, & Perrone, 2003), electronic commerce systems (Saleh, 2002), data warehousing (Dolk, 2000), bioinformatics (Bornberg-Bauer & Paton, 2002) and others. The language uses multiple views to specify system’s structure and behavior. Modeling tools supporting the development of UML diagrams are available from a number of commercial vendors and the open source community (OMG, 2006b; Robbins & Redmiles, 2000).
Table 1 depicts the origin and descent of UML. The recent version UML 2.0 supports thirteen different diagram types. Table 2 overviews the main concepts of each diagram, a more detailed description is given below. For a full description of all semantics see (OMG, 2005a, 2005b, 2006a, 2006c) respectively the available secondary literature (Fowler, 2004; Rumbaugh et al., 1998).Table 1.
History of UML (Fowler, 2004, pp. 151-159; Kobryn, 1999, p. 30)
|1995||0.8||Origin of UML, so-called “Unified Method”|
|1997||1.0||Initial submission to OMG|
|1997||1.1||Final submission to OMG|
|1998||1.2||Editorial revision with no significant technical changes|
|1999||1.3||New use case relationships, revised activity diagram semantics|
|2001||1.4||Minor revisions, addition of profiles|
|2003||1.5||Adding action semantics|
|2005||1.4.2||Standardized by the International Organization for Standardization (ISO/IEC 19501:2005)|
|2005/6||2.0||Deep changes to meta-model, new diagram types, improved expressiveness|
Key Terms in this Chapter
Bandwidth: A measure of the data transmission capacity of a communications link.
Digital Divide: The term digital divide describes the fact that the world can be divided into people who do and people who do not have access to - and the capability to use - modern information technology, such as the telephone, television, or the Internet.
Ethernet: A communications standard (IEEE 802.3) for Local Area Networks (LAN). When a device wishes to transmit, it waits until the link is empty and then transmits. In the event that two or more devices transmit simultaneously (collision), all devices stop transmitting and wait a random time period before attempting to retransmit.
Intranet: Computer network contained entirely within an organization.
LAN: Local Area Network. Group of computers and other devices sharing a single communications link. Typically, the longest distance between any two connections is a few kilometers. Usually owned by a single organization.
Service-Learning: A form of experiential education in which students engage in activities that address human and community needs together with structured opportunities intentionally designed to promote student learning and development.