CC 2007, 2011 attribution - R.B. Allen Information System Architectures and Services

CC 2007, 2011 attribution - R.B. Allen Architectures The architecture is the relationship of the components of the information system. One useful framework is the Model-View-Controller (MVC)

CC 2007, 2011 attribution - R.B. Allen Managing Complexity with Distributed Systems There’s additional complexity when the components of the information system are distributed across several machines in a network. Some approaches for managing complexity: –Layering –Modularity –Interoperability

CC 2007, 2011 attribution - R.B. Allen Service Oriented Architectures (SOA) It’s helpful to define complex information systems in terms of the services they provide. We would like to work with architectures which make it easy to implement services. –This turns out to fit well with systems analysis and object-oriented design –In research environments, this is often implemented with java apache “tomcat” web server Repositories are content management systems which support services. –Digital Libraries, Enterprise Content Management Systems, and Archives can all use repositories.

CC 2007, 2011 attribution - R.B. Allen Information Institutions Importance of information management in society is shown by the fact that many societal institutions deal with the use of information Memory institutions, Cultural Institutions, Knowledge Institutions Libraries, Archives, Museums, Universities Trusted information professionals Librarians, Archivists, Journalists, Notaries To what extent can technology replace trusted humans?

CC 2007, 2011 attribution - R.B. Allen Libraries A library needs to support collection management and content access. This functions (services) can be summarized with the acronym: S.Selection Deciding what should be included O.Organization Metadata AAccess Easy to use. Also support reference and collaboration P.Persistence Continuity and Preservation

CC 2007, 2011 attribution - R.B. Allen Archives Archives typically collect material for which there’s only one copy: Manuscripts, letters, personal notes Archives emphasize persistence of content. The repository should be trusted. That is, we should have confidence that the contents of have not been tampered with. The Open Archival Information Systems (OAIS) Reference Model describes the generic components of an archive

CC 2007, 2011 attribution - R.B. Allen Digital Preservation Unlike traditional media, digital media are ephemeral. Even if we it saving it is not easy: –The ability to read the message format and character codes may change –It may not be possible to access the storage media hardware. –If the material is interactive, we need to save that interactivity. The best bet is to use standard formats.

CC 2007, 2011 attribution - R.B. Allen LOCKSS: Lots of Copies Keeps Stuff Safe If there aren’t any copies, digital media is gone when it’s deleted It’s easy to make copies, but we have to keep track of them. Furthermore, the copies can tell whether somebody has tampered with the original. LOCKSS is a framework for ensuring managing this.

CC 2007, 2011 attribution - R.B. Allen Knowledge Management What policies should we develop for managing the knowledge resources of an organization? For instance, –What books, databases, and periodicals should be available? Use thesauri to organize content.

CC 2007, 2011 attribution - R.B. Allen Electronic Records The information is more important than the medium Records document transactions. –Birth, marriage death, real estate, etc. Records management: –Records need to be trusted. –Not all materials (e.g., s need to be saved) –Some records can be deleted when they have outlived their lifespan.

CC 2007, 2011 attribution - R.B. Allen Business Process Design Usually based on flow through an organization rather than hierarchical control. Rather than focus on hierarchical structure, focus on flow across the organization Organizations have social constraints –Procedures can’t be over constrained

CC 2007, 2011 attribution - R.B. Allen Information System Specification, Development, and Implementation System analysis with UML (week 3) Stakeholders? Requirements.

CC 2007, 2011 attribution - R.B. Allen Requirements These are such complex systems that figuring out what is needed is not easy. –Functional requirements Requirements Modeling

CC 2007, 2011 attribution - R.B. Allen Agile System Development Can we specify all parameters in requirements Lots of testing

CC 2007, 2011 attribution - R.B. Allen System Management and Evaluation What makes an effective information system? Metrics

CC 2007, 2011 attribution - R.B. Allen Risk Analysis and Risk Management There are many types of risk, how can we understand them and defend against them? What’s the chance that records could be lost? Attacked and corrupted?

CC 2007, 2011 attribution - R.B. Allen Security and Encryption Analyzing risks to security Human elements vs technical issues. Encryption DES – Digital Encryption Standard Public Key Encryption Key Distribution