System Design & Class Overview System Design & Class Overview

Spring 2006, 17 April Spring 2006, 17 April

Bharat MehraBharat MehraIS 520 (Organization and Representation of Information) IS 520 (Organization and Representation of Information)

School of Information SciencesSchool of Information SciencesUniversity of TennesseeUniversity of Tennessee

Topic Contents Topic Contents

• What is a System?What is a System?• Components of a SystemComponents of a System• What LIS “Systems” May We What LIS “Systems” May We

Encounter?Encounter?• Socio-Technical SystemsSocio-Technical Systems• Kinds of SystemsKinds of Systems• Complex and Simple SystemsComplex and Simple Systems• What are Information Systems?What are Information Systems?• What is Design?What is Design?• What is Systems Design?What is Systems Design?

Life-Cycle VariationsLife-Cycle Variations• Ad-HocAd-Hoc• WaterfallWaterfall• IterativeIterative

• Prototyping ModelPrototyping Model

• Exploratory ModelExploratory Model

• Spiral ModelSpiral Model

• Re-Use ModelRe-Use Model

• Kinds of EnvironmentsKinds of Environments

• System-Centered and User-System-Centered and User-CenteredCentered

What is a System?What is a System?• An assemblage of inter-related elements comprising a unified whole

• In Latin means to combine, to set up, to place together

• Consists of components (or elements) which are connected together in order to facilitate the flow of information, matter, or energy • Often used to describe a set of entities which interact

http://en.wikipedia.org/wiki/System

Components of a SystemComponents of a System

• Inter-related elements or parts: human, non-human

• Sub-systems

• Processes and organizational structures

• Goals or purposes of the system

What LIS “Systems” May We Encounter? What LIS “Systems” May We Encounter?

• Knowledge, Information, DataKnowledge, Information, Data

• Policies and proceduresPolicies and procedures

• CollectionsCollections

• Services and resourcesServices and resources

• Information organization and Information organization and representation systems representation systems

• Information retrieval systemsInformation retrieval systems

• Others?Others?

LIS Systems as Socio-Technical Systems LIS Systems as Socio-Technical Systems

Connect “networks of technology, Connect “networks of technology, information, documents, people, and information, documents, people, and practices” and “find multidisciplinary practices” and “find multidisciplinary ways of talking about heterogeneity: ways of talking about heterogeneity: of talking, at the same time, of social of talking, at the same time, of social and technical relations even-and technical relations even-handedly without putting one or the handedly without putting one or the other in a black box whose contents other in a black box whose contents we agree not to explore”we agree not to explore”

(Van House, Bishop, and Buttenfield, 2003, p. 1)(Van House, Bishop, and Buttenfield, 2003, p. 1)

Kinds of Systems Kinds of Systems

• Physical and conceptual systemsPhysical and conceptual systems

• Open and closed systemsOpen and closed systems

• Static and dynamic systems Static and dynamic systems

Complex and Simple Systems Complex and Simple Systems • Non-linear and/or continuous Non-linear and/or continuous • Large number of mutually interacting dynamical partsLarge number of mutually interacting dynamical parts

• Principle of superposition does not apply (not sum of its parts)Principle of superposition does not apply (not sum of its parts)

• Change in one is not proportional to change in anotherChange in one is not proportional to change in another

• Unpredictable but interesting (exhibit uncoordinated behavior)Unpredictable but interesting (exhibit uncoordinated behavior)

• Biological vs. Engineered Systems Biological vs. Engineered Systems

• Flexible in exhibiting qualitatively different behaviors during Flexible in exhibiting qualitatively different behaviors during different times (bifurcation) different times (bifurcation)

• Examples in: Examples in: neuroscience, meteorology, physics, computer neuroscience, meteorology, physics, computer science, artificial life, economics, earth quake prediction, heart cell science, artificial life, economics, earth quake prediction, heart cell synchronization, immune systems synchronization, immune systems

Linear graph

Characteristics of Complex Systems Characteristics of Complex Systems

Highly structured system, which shows structure with variations Highly structured system, which shows structure with variations (Goldenfeld and Kadanoff) (Goldenfeld and Kadanoff)

One whose evolution is very sensitive to initial conditions or to small One whose evolution is very sensitive to initial conditions or to small perturbationsperturbations

One in which the number of independent interacting components is One in which the number of independent interacting components is large, or one in which there are multiple pathways by which the system large, or one in which there are multiple pathways by which the system can evolve (Whitesides and Ismagilov) can evolve (Whitesides and Ismagilov)

One that by design or function or both is difficult to understand and One that by design or function or both is difficult to understand and verify (Weng, Bhalla and Iyengar) verify (Weng, Bhalla and Iyengar)

There are multiple interactions between many different components There are multiple interactions between many different components (D. Rind) (D. Rind)

Process that constantly evolves and unfolds over time (W. Brian Process that constantly evolves and unfolds over time (W. Brian Arthur). Arthur).

Complex Systems in LIS Complex Systems in LIS

Relationships are non-linearRelationships are non-linear

Relationships contain feedback loopsRelationships contain feedback loops

Complex systems are openComplex systems are open

Complex systems have a historyComplex systems have a history

Complex systems may be nestedComplex systems may be nested

Boundaries are difficult to determineBoundaries are difficult to determine

Network topologyNetwork topology

What are Information Systems?What are Information Systems?

• An interconnected set of information resources under the An interconnected set of information resources under the same direct management control that shares common same direct management control that shares common functionality. Includes hardware, software, information, functionality. Includes hardware, software, information, data, applications, communications, and people.data, applications, communications, and people.

• The organized collection, processing, transmission, and The organized collection, processing, transmission, and dissemination of information in accordance with defined dissemination of information in accordance with defined procedures, whether automated or manual. procedures, whether automated or manual.

• An information system is the arrangement of people, data, An information system is the arrangement of people, data, processes, presentation of data, and information processes, presentation of data, and information technology that supports our everyday needs.technology that supports our everyday needs.

• Involved in efficient creation and capture, organization Involved in efficient creation and capture, organization and representation, storage and update, management and and representation, storage and update, management and manipulation, processing, integration and analysis, retrieval manipulation, processing, integration and analysis, retrieval and display, and dissemination of information and display, and dissemination of information

Components of Information Systems in LISComponents of Information Systems in LIS• Data/Information/KnowledgeData/Information/Knowledge• Something to process and describeSomething to process and describe• Something to organize and represent (surrogates):Something to organize and represent (surrogates):

structure or frameworkstructure or framework• Something to make sure it works: Something to make sure it works:

consistency, rigor, efficiencyconsistency, rigor, efficiency• Something to search Something to search • Something to retrieve or provide accessSomething to retrieve or provide access• Interface between the system and peopleInterface between the system and people

Intellectual works and their manifestationsIntellectual works and their manifestationsMetadata standards in various environments Metadata standards in various environments Cataloging and authority controlCataloging and authority controlMetadata coding and crosswalksMetadata coding and crosswalksDigital library developmentDigital library developmentSubject access and vocabulary controlSubject access and vocabulary controlConcept mappingConcept mapping Indexing and abstractingIndexing and abstracting Classification systemsClassification systemsCognitive category analysisCognitive category analysis System designSystem design

Examples of Information SystemsExamples of Information Systems

GIS: a computer system designed to allow users to collect, manage GIS: a computer system designed to allow users to collect, manage and analyze large volumes of spatially referenced information and and analyze large volumes of spatially referenced information and associated attribute dataassociated attribute data

MIS An information collection and analysis system, usually MIS An information collection and analysis system, usually computerized, that facilitates access to program and participant computerized, that facilitates access to program and participant information. It is usually designed to help managers plan and direct information. It is usually designed to help managers plan and direct business and organizational operations business and organizational operations

Radiology IS is used by radiology departments to store, manipulate Radiology IS is used by radiology departments to store, manipulate and distribute patient radiological data and imagery. The system and distribute patient radiological data and imagery. The system generally comprises of patient tracking and scheduling, result reporting generally comprises of patient tracking and scheduling, result reporting and image tracking capabilitiesand image tracking capabilities

Network IS is a protocol designed by Sun Microsystems in order to Network IS is a protocol designed by Sun Microsystems in order to share common information across a NIS domain, which may consist of share common information across a NIS domain, which may consist of an entire LAN, or just a part of it. It can export password databases, an entire LAN, or just a part of it. It can export password databases, service databases, groups information and more.service databases, groups information and more.

What is Design?What is Design?

"Design" (as a verb) refers to the process of originating and "Design" (as a verb) refers to the process of originating and developing a plan for a specific purpose (machine, building, developing a plan for a specific purpose (machine, building, product, etc.)product, etc.)

““Design" (as a noun) is used both for the final plan or Design" (as a noun) is used both for the final plan or proposal (a drawing, model, or other description), or the proposal (a drawing, model, or other description), or the result of implementing that plan or proposal (the object result of implementing that plan or proposal (the object produced)produced)

Designing normally requires considering Designing normally requires considering aestheticaesthetic, , functionalfunctional, and many other aspects of an object, which , and many other aspects of an object, which usually requires considerable usually requires considerable researchresearch, , thoughtthought, , modellingmodelling, , iterative adjustment, and re-design: Multi-Pronged iterative adjustment, and re-design: Multi-Pronged ApproachApproach

What is the Design Process?What is the Design Process?

ReflectiveReflective

Critical Critical

Situated Cognition Situated Cognition

Contextual specificityContextual specificity

Changes over timeChanges over time

Behaves as a complex system Behaves as a complex system

What is Systems Design?What is Systems Design?

Popularly applied in the context of systems that Popularly applied in the context of systems that incorporate computer technology: hardware, incorporate computer technology: hardware, software, user interfacesoftware, user interface The process or art of defining the The process or art of defining the hardwarehardware and and softwaresoftware architecture, components, modules, architecture, components, modules, interfaces, and interfaces, and datadata for a computer system to for a computer system to satisfy specified requirementssatisfy specified requirements

How does this work for Socio-Technical Systems?How does this work for Socio-Technical Systems?

Info Systems Design in “Socio-Technical” SettingsInfo Systems Design in “Socio-Technical” Settings

Typical Tasks in the Development Process Life-Cycle

What are the common goals and objectives and what activities and resources need to be considered for the ‘system’ to achieve those goals/objectives? How much “cost” will be entailed in the process?

Info Systems Design in “Socio-Technical” SettingsInfo Systems Design in “Socio-Technical” Settings Process Model: Typical activities include the following:• System conceptualization

• System requirements and benefits analysis

• Project adoption and project scoping

• System design

• Specification of component requirements

• Architectural design

• Detailed design

• Unit development

• System integration and testing

• Installation at site

• Site testing and acceptance

• Training and documentation

• Implementation

• Maintenance

Feedback, control methods, timing of activities

Life-Cycle Variations Life-Cycle Variations Ad-hoc development: chaotic, haphazard, relies entirely on Ad-hoc development: chaotic, haphazard, relies entirely on skills/experience of individuals, process+capability is skills/experience of individuals, process+capability is unpredictable, process is constantly changed or modified unpredictable, process is constantly changed or modified as the work progressesas the work progresses

Schedules, budgets, functionality, and quality are Schedules, budgets, functionality, and quality are inconsistentinconsistent

Performance depends on individual capabilities and varies Performance depends on individual capabilities and varies based on skills, knowledge, and motivation based on skills, knowledge, and motivation

Waterfall Model Waterfall Model Earliest structured system development, rigid, unrealistic Earliest structured system development, rigid, unrealistic for short-term deadline, comprises the following steps: for short-term deadline, comprises the following steps: system conceptualization, system analysis, system design, system conceptualization, system analysis, system design, implementation and testingimplementation and testing

Problems: Real projects don’t follow sequential stages, Problems: Real projects don’t follow sequential stages, does not account for uncertainty, time consuming processdoes not account for uncertainty, time consuming process

Iterative Model Iterative Model

Provides faster results, require less up-front information, and offer greater flexibility

Project is divided into small parts that allows the

team to demonstrate results earlier on in the process and obtain valuable feedback

Each iteration is actually a mini-Waterfall process

Challenges: Active involvement of user community throughout project development, communication and coordination skills important, controlled mechanism for handling requests important, “scope creep”

Prototyping Model Prototyping Model • Build a simplified version of the proposed system• Present it to the customer for consideration • Customer provides feedback to the developer, who goes back to refine the system requirements to incorporate the additional information• Prototype is thrown away and entirely new programs are developed once requirements are identified

FORMS• Creation of the major user interfaces without any substantive work• Development of an abbreviated system version that performs a limited subset of functions• Development of a paper system (depicting proposed screens, reports, relationships etc.)• Use of an existing system or system components to demonstrate some functions that will be included in the developed system

Prototyping Model Prototyping Model

STAGESRequirements Definition/CollectionDesignPrototype Creation/ModificationAssessmentPrototype RefinementSystem Implementation.

PROBLEMS• Prototyping can lead to false expectations. • Prototyping can lead to poorly designed systems

Exploratory Model Exploratory Model • Impossible to identify any of the requirements for a system at the beginning of the project

• Artificial Intelligence projects are good candidates because much of the research in these areas is based on guess-work, estimation, and hypothesis

• Assumption is made as to how the system might work and then rapid iterations are used to quickly incorporate suggested changes and build a usable system • A distinguishing characteristic is the absence of precise specifications • Validation is based on adequacy of the end result and not on its adherence to pre-conceived requirements.

Exploratory Model Exploratory Model STAGES

Initial Specification Development

System Construction/Modification

System Test

System Implementation

PROBLEMS

It is difficult to measure or predict its cost-effectiveness

Yields often inefficient or crudely designed systems, since no forethought is given as to how to produce a streamlined system

Spiral Model Spiral Model Introduces a new component - risk-assessment.

An initial version of the system is developed, and then repetitively modifiedbased on input received from customer evaluations. The development of each version of the system is carefully designed using the steps involved in the Waterfall Model. With each iteration around the spiral (beginning at the center and workingoutward), progressively more complete versions of the system are built

Risk assessment is included as a step in the development process as a means of evaluating each version of the system to determine whether or not development should continue.

If the customer decides that any identified risks are too great, the project may be halted.

STAGESProject ObjectivesRisk AssessmentEngineering & ProductionPlanning and Management

PROBLEMSDue to the relative newness of the Spiral Model, it is difficult to assess its strengths andweaknessesThe measurement of risk is a feature that occurs everyday in real-life situations, but (unfortunately) not as often in the system development industry

Reuse Model Reuse Model The basic premise behind the Reuse Model is that systems should be built using existing components, as opposed to custom-building

Within the Reuse Model, libraries of software modules are maintained that can be copied for use in any system.

These components are of two types: procedural modules and database modules

When building a new system, the developer will “borrow” a copy of a module from the system library and then plug it into a function or procedure. If the needed module is not available, the developer will build it, and store a copy in the system library for future usage

STAGES

Definition of Requirements Definition of Objects Collection of Objects Creation of Customized Objects Prototype Assembly

Prototype Evaluation Requirements Refinement

Objects Refinement

Four Kinds of Environments Four Kinds of Environments Suitable approaches to system analysis, design, development, and implementation are based on the relationship between the information system and its organizational environment

The Unchanging Environment: Information requirements are unchanging for thelifetime of the system, Requirements can be stated unambiguously and comprehensively, High degree of accuracy is essential, Formal methods (such as the Waterfall or Spiral Models) would provide the completeness and precision required by the system

The Turbulent Environment: Organization is undergoing constant change andsystem requirements are always changing, Successful methods wouldinclude those, which incorporate rapid development, some throwaway code (such as inPrototyping), the maximum use of reusable code, and a highly modular design

The Uncertain Environment: Requirements of the system are unknown orUncertain, Not possible to define requirements accurately ahead of time because thesituation is new or the system being employed is highly innovative, Developmentmethods must emphasize learning, Experimental Process Models, which take advantageof prototyping and rapid development, are most appropriate

The Adaptive Environment: Environment may change in reaction to the systembeing developed, thus initiating a changed set of requirements. Teaching systems andexpert systems fall into this category. For these systems, adaptation is key, and themethodology must allow for a straightforward introduction of new rules.

System-Centered and User-Centered DesignSystem-Centered and User-Centered Design

Paradigm shift (Dervin and Nilan, 1986)

System-centered study: BLAISE-LINE and The British National Bibliography: profiles of users and uses by Jane Bishop & Peter R. Lewis

A particular information system (the first online form of the British National Bibliography) was the center. Around this center, the users and their way to interact with this system were analyzed. Questions: 'do users like the system?‘ 'how they will use the system in the future?' were categorized around different areas: uses of the system, attitudes towards the system, and alternatives for the used system. Within these main areas sub-areas are covered.

System-Centered DesignSystem-Centered DesignOne of the main differences between these two studies is that one study deals with an actual information system, the other study (the user-centered study) deals with the information behavior and less with functionalities of particular systems. System metaphors

User-Centered DesignUser-Centered DesignThe Dynamic Scientific-Information User by William Garvey et al.

The authors of this study wanted to know more about information needs, habits and variations of information use in the different stages of scientists' work and life. To do so they examined the work, daily job routine and task analysis implicit in the process of publishing scientific work. The boundaries are clearly set, by articulating the clear focus group of the study (scientists in certain areas in the task of designing their work, but finally writing scholarly publications.)

User-Centered DesignUser-Centered DesignSystematic individuality Qualitative methods

System-Centered and User-Centered DesignSystem-Centered and User-Centered Design