Information System Architectures

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17 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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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

A

Access


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., emails 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