THE INFORMATION-TECHNOLOGY-PEOPLE ABSTRACTION HIERARCHY: A

TOOL FOR COMPLEX INFORMATION SYSTEM DESIGN

Arthur C. Jones

Thesis Defense Presentation

Thesis Committee

• Mike McNeese (thesis advisor)• Steve Sawyer• Dan Lorence

AbstractThis work presents a general model for developing the requirements and constraints for the construction of information systems. The model is based upon Rasmussen’s [1986] abstraction hierarchy model, but substitutes the elements of information, technology, and people as peers in place of the traditional whole-part hierarchical decomposition. The resulting I-T-P Abstraction Hierarchy is shown to have utility for information systems engineers and is demonstrated by applying the model to the design of a system for emergency services dispatch operations.

Who is this guy?

• Long time computer enthusiast (hardware, networking, programming, database designer)

• Paramedic – instructor (various environments)

• IST student

Outline of presentation

• Some preliminary information, definitions, etc.• Abstraction Hierarchy Models• The Information-Technology-People trichotomy• My model, the general I-T-P AH• Demonstration

– WDA– Domain-specific model– Implications– Prototype construction

• Conclusion & Future Work

What are “Information Systems”

• Information System = coordinated activity involving information, technology, people.

• I-T-P Trichotomy exists throughout literature, but using different names.

What are “Critical Incidents”

• The term “critical incident” as applied here is an extension of Flanagan’s [1954] concept: “… defined as extreme behavior, either outstandingly effective or ineffective with respect to attaining the general aims of the activity.” The extension applied to this definition is in consideration of the response to unforeseen circumstances, and an acknowledgement that some circumstances can not be foreseen.

Critical Incident Information Management Systems

• Importance• Complexity• Potential for failure• Results of failure• Motivation for better systems

What is “better?”

• “Better” ? more complex system– Trauma shears– The “splashback” problem [Vicente 2004]

• “Better” = able to adapt– Requires a more complex design process

Abstraction Hierarchy Models

Physical Form

Physical Function

Generalized Function

Abstract Function

Functional Purpose

Means –Ends

AbstractionHierarchy

ComponentSubassemblyFunctional UnitSub-SystemTotal System

Whole-Part Structural Decomposition Hierarchy

Most “concrete” form

Representation of physical processes of the system

Concept over implementation

Causal network, the flow through the system

Most abstract form; overall reason for the system

Abstraction Hierarchy Models

• From Rasmussen [1986]• Abstraction hierarchy along vertical axis

– Choice of layers can vary depending on domain and approach

• Structural decomposition hierarchy (“whole-part”) along horizontal axis– Choice of labels can vary here as well

• Why-What-How relationships between strata• Each layer is a complete representation of the

same system

Abstraction Hierarchy Models

Configuration and weight, size, “style” and color

Physical Form

Mechanical drum drive; pump and valve function; electric/gas heating circuit

Physical Function

Washing, draining, drying, heating, temperature control

Generalized Function

Energy, water, and detergent flow topology

Abstract Function

Washing specifications;Energy Waste requirements

Functional Purpose

Means –Ends

AbstractionHierarchy

ComponentSubassemblyFunctional UnitSub-SystemTotal System

Whole-Part Structural Decomposition Hierarchy

Abstraction Hierarchy Models

• Serve as models for Work Domain Analysis

• Cell contents are objects (nouns) which represent the system (the work domain)

• Task analysis can be mapped onto AH models, as tasks take place within a work domain, but task analysis can not be used to complete the model.

Ecological Interface Design (EID)

• From Rasmussen and Vicente [1994]• Ecological = natural = uncontrolled.• Contrasted with intentional (well defined)

systems.• Uses AH’s why-what-how relationships to define

human-computer interaction needs and constraints.

• Examples applied to nuclear power plant monitoring and control, manufacturing plants, etc.

Information, Technology, and People

• Part of the foundational philosophy of the School of IST.• Sawyer, S. & Chen, T.; 2002; Conceptualizing Information

Technology and Studying Information Systems: Trends and Issues; in Myers, M. & Wynn, E. & DeGross, J. (Eds.) Global and Organizational Discourse About Information Technology,London: Kluwer, 109-131

• Vicente [2004]: “soft technologies”• Xia & Lee [2004]: “organizational factors” • Consider:

– Computer science: efficiency is measured in human-centric terms– Library science: Dewey Decimal system = technology– HCI: the purpose of humans interfacing with computers is information

transfer

My Thesis:

• Adapting the abstraction hierarchy model to complex information systems design can aid in achieving the ability for those systems to adapt to novel or extraordinary circumstances. (Critical Incident Information Management Systems)

• Demonstration application: CIIMS for Emergency Services Dispatch

Approach:

• An abstraction hierarchy (AH) was developed which targets the composition of a comprehensive information system. In contrast to the typical abstraction hierarchy’s whole-part decomposition of systems into sub-systems, units, assemblies, and components, I have implemented a decomposition of the system into the three peer elements of information, technology, and people.

General I-T-P AH ModelStructural Decomposition

Information Technology People

Purpose / Goal Overall outcome improvement

Abstract Function

Description of environment and conveyance of decision makers’ wishes Understanding and manipulation of environment

Generalized Function

Refined or transformed data which accurately describe

relevant conditions and users’ wishes in a timely fashion

Organization, transformation, refinement, storage,

movement, presentation, etc. of data

Understanding of variables describing actual and desired

conditions

Real-World Function

Representation of exhaustive set of available

details

Presentation of data to users, and interpretation of users’ directions

Analysis of conditions and direction of activity

Leve

l of A

bstr

actio

n

Real-World Form Raw Data

Data communications / storage / processing capabilities, interface hardware / software,

database structure, decision support algorithms, etc.

Users

Approach:

• Work Domain Analysis• Populate AH model’s cells• Infer needs of CIIMS from the model• Develop initial prototypes• Enter development cycle

Work Domain Analysis

• Literature Review: EMD, ATC, Emergency Medicine (for both content and methodology)

• Prior involvement• Site visits to interview/observe EMD

activity

Beaver Stadium EMS

• ~108K spectators + surrounding parking areas making it the 3rd

largest population center in PA (http://wpsx.psu.edu/ourtown/statecollege/1.html)

• >40 response teams with varying capabilities

• 10-20 incidents per game, with large variation in number and type

Site Visits

• Four centers• Represent different

environments• Familiar to author• Interviews with

administrators and dispatchers + observation

Findings of WDA

• Diversity of approach to mission.• Technology is homogenous,

implementation varies tremendously.• Current information systems work well for

normal operations, though human element must learn and adapt the most.

• ESD is a “gateway” to ES jobs; not so much other ESD jobs (probably due to operational differences between centers)

Findings of WDA

• Great deal of “free” information movement between personnel, as well as loosely-formed information held by personnel outside of technology.

• Critical incidents inside the ECC do not necessarily equate to critical incidents in the field.

• Technology can hide information.

Findings of WDA

• Overall goal is appropriate resource allocation.

• This is approached on an incident-by-incident basis.

• Current technology-based systems do not support real-time aggregation of incident data to reveal overall resources/needs status.

WDA – Interesting Observation

WDA ? I-T-P AHStructural Decomposition

Information Technology People

Purpose / Goal Minimize loss-of-life, injury exacerbation, property loss or damage

Abstract Function

Meaningful representation of conditions in the context of established triage and protocol criteria Appropriate allocation of resources

Generalized Function

Timely and accurate description of conditions

Organization, transformation, refinement, storage,

movement, presentation, etc. of data

Work assignments (or withholdings) for resource

inventory

Real-World Function

Representation of availability and capability of resource inventory as

well as requests for resources

Maintenance of database integrity with support for real-time data input/output

& directed sharing

Decisions based upon available data

Leve

l of A

bstr

actio

n

Real-World Form

Resource inventory and needs

assessment data

Data structure & accompanying interfaces; data distribution policies (assumes

hardware/network infrastructure is in place)

Emergency communications

personnel

Implications of the completed I-T-P AH model

• Incidents are only a single component of the information system requirements.

• Resources (police, fire, medical, etc.) and their specific capabilities are another component.

• Resource availability is based on current assignment.

• Other factors, notably geography and policy, influence resource assignability.

• Since these factors are locally defined, CIIMS must be customized for each implementation.

Conclusions

• The I-T-P Abstraction Hierarchy model can reveal relationships important to information systems designers.

• Systems built from this model should be better able to adapt to atypical and novel circumstances.

Future Efforts

• Extend the domain example pool to business, medicine, etc.

• Quantify performance comparisons.• Assess variations of the model for

usefulness. If the I-T-P elements are truly peers, their arrangement is arbitrary:

Variations of the model (I-P-T)Structural Decomposition

Information People Technology

Purpose / Goal Increase in overall value of fund

Abstract Function

Description of business environment and conveyance of decision makers’ wishes

Understanding and manipulation of environment (buying / selling)

Generalized Function

Refined or transformed data which accurately describe

relevant conditions and users’ wishes in a timely fashion

Understanding of business practices, legal issues,

corporate interactions, etc.

Organization, transformation, refinement, storage, movement,

presentation, etc. of data

Real-World Function

Representation of exhaustive set of available

details

Analysis of business conditions and direction to buy/sell particular stocks

Presentation of data to users, and interpretation of users’

directions Leve

l of A

bstr

actio

n

Real-World Form

Stock market data, business news, trend

analysis data, etc. Stock Market Fund Managers

Communications links with data warehouses and stock traders, DSS processes and displays, etc.

Variations of the model (T-I-P)Structural Decomposition

Technology Information People

Purpose / Goal

Aid in the design and construction of complex information systems with an emphasis on scalability for complexity increases.

Abstract Function Documented understanding of scope of system Formulation of possible solutions

Generalized Function

Description of interactions between elemental units Presentation of model Understanding of system

requirements and constraints

Real-World Function

Decomposition of system into peer elements

Communication of author’s proposal with supporting documentation System models

Leve

l of A

bstr

actio

n

Real-World Form

The I-T-P Abstraction Hierarchy model My Thesis Information systems

designers

Questions?

http://www.personal.psu.edu/acj100/thesis/defense.pdf

http://www.personal.psu.edu/acj100/thesis/final.pdf

References• Flanagan, J. C.; The critical incident technique; Psychological

Bulletin; Vol. 51, No. 4, pp. 327-359; (July 1954). • Vicente, Kim J.; The Human Factor; Routledge; New York, NY ;

(2004)• Rasmussen, Jens; Elsevier Science Publishing Co., Inc.; New York,

NY.; Information Processing and Human-Machine Interaction; North-Holland series in system science and engineering; volume 12; (1986)

• Sawyer, S. & Chen, T.; Conceptualizing Information Technology and Studying Information Systems: Trends and Issues; in Myers, M. & Wynn, E. & DeGross, J. (Eds.) Global and Organizational Discourse About Information Technology,London: Kluwer, pp.109-131; (2002)

• Xia, Weidong & Lee, Gwanhoo; Grasping the Complexity of IS Development Projects; Communications of the ACM; Volume 47, Number 5; (May 2004)