The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology has been formulated and applied over a five-year period. It has proven to be a unique, integrated approach utilizing a top-down, structured technique to define and document the system of interest; a knowledge engineering technique to collect and organize system descriptive information; a rapid prototyping technique to perform preliminary system performance analysis; and a sophisticated simulation technique to perform in-depth system performance analysis

Bachert, Robert F.

Evers, Ken H.

English

NASA Technical Reports Server

N 8 8 -  1 7 2 2 7  
THE IDEAL MODELING METHODOLOGY: 
CAPABILITIES AND APPLICATIONS 
Ken H. Evers 
SofTech, Inc. 
3100 Presidential Dr. 
Fairborn, Ohio 45324-2039 
Robert F. Bachert 
Armstrong Aerospace Medical Research Laboratory 
Wright-Patterson Air Force Base, Ohio 45433 
The IDEAL (Integrated Design and 
En g in e e ri n g An a I y s i s Lan g u ag e s) mod e I i n g 
methodology has been formulated and applied 
over a five year period. It has proven to be a 
unique, integrated approach that utilizes a 
top-down, structured technique to define and 
document the system of interest; a knowledge 
engineering technique to collect and organize 
system descript ive information; a rapid 
prototyping technique to perform preliminary 
system per fo rmance analysis;  and a 
sophist icated simulat ion technique to 
per fo rm in-depth system performance 
analysis. 
The use of modeling and simulation as a tool 
within the system analysis process is 
becoming an  ever increasingly important 
capability. As part of this trend, the IDEAL 
methodology is making modeling and 
IDEAL provides these improvements in two 
ways. First, IDEAL permits the user to 
concentrate primarily on the nature of the 
system being anayzed rather than the 
simulation effort itself. Second, IDEAL 
permits more accurate models to be developed 
resulting in a better understanding and a more 
thorough anaysis of the modeled system. 
IDEAL is the unique anaysis capability it is 
because, above al l  else, i t  provides a 
communication and documentation vehicle. 
The design and analysis of any system 
(program scheduling and management; 
so f tware  and /o r  ha rdware  sys tems;  
man-machine systems; large or small  
systems) requires, to one degree or another, 
an integrated team effort. For example, the 
development of a man-machine system could 
reasonably involve hardware and software 
engineers,  human fac to rs  engineers,  
psychologists, design engineers, and program 
managers. IDEAL provides the features needed 
to integrate or blend these varied backgrounds 
into an effective working team. It is through 
this team effort that the best possible 
system is developed in the most efficient 
manner. 
IDEAL has been effectively applied to a wide 
range of system types. Examples of these 
app l i ca t i ons  a r e  a m a n - i n - t h e - l o o p  
Surface-to-Air Missile (SAM) system, data 
base development programs, sof tware 
development programs, aircraf t  radar 
systems, automated communications systems, 
and computer bus architectures. 
This paper will discuss the capabilities of 
IDEAL, the types of system insights received 
while developing an IDEAL model, and the 
types of system analysis that have been 
performed using IDEAL. 
153 
https://ntrs.nasa.gov/search.jsp?R=19880007843 2020-03-20T07:32:11+00:00Z
INTRODUCTION 
Simulation techniques are used to model or 
duplicate the behavior aspects of real-world 
or conceptual systems. These techniques are 
applicable to all phases of a systems life 
cycle. Simulation is a powerful method of 
analysis or evaluating a system without 
requiring the time and cost of building or 
modifying the actual system. The 
development of a simulation model requires a 
system description in the form of a functional 
model which is combined with timing and 
precedent relationships to form a dynamic 
computer simulation. 
Current simulation techniques are highly 
dependent upon the experience and skill of 
those applying them. However, the techniques 
do not integrate all the personal critical to 
the success of the systems analysis and 
design. The lack of personnel integration 
results in the simulation expert having to 
define the system as he understands it, to 
define the analysis goals, to solve the 
problem as he understands it, and to exercise 
the simulation and interpret the results as he 
understands them. This usually results in a 
biased and limited view that is inadequately, 
verfied, validated, and communicated. Poor 
and imcomplete problem definition and 
system description results in an incomplete 
and inaccurate performance analysis of the 
system. 
The IDEAL (Integrated Design, Engineering, 
and Analysis Languages) technique was 
developed to provide the features necessary 
to define or bound the problem, to develop a 
validated functional model of the system, to 
build a simulation model based on the 
functional model, and to communicate and 
discuss the analysis approach and results via 
the funtional model. It is through team 
efforts that the best possible system 
simulation is developed and the most 
complete system analysis performed. 
SIMULATION PROCESS 
The development of a simulation for 
analyzing a system requires a team effort. 
The larger and more complex the system is, 
the more difficult is the team effort. The 
team is normally composed of analysts, 
system experts, and project managers. The 
system analyst is the focal point for the 
entire effort. I t  is the analyst's 
responsibility to identify the purpose for the 
proposed simulation from the viewpoint of 
both the system experts and the project 
management. 
Guided by the viewpoint and agreed upon 
purpose, the analyst, working as the team's 
focal point, steps through a systematic 
approach to identify and collect the 
information necessary for a system 
description and operation scenarios, to 
develop the system simulation from the 
system description, to exercise the 
simulation in a manner controlled by the 
operational scenario, and to recommend a 
proposed solution for  satisfying the 
simulation purpose. 
This general view of the simulation process 
is illustrated in more detail by the model in 
figure 1. The simulation process, upon which 
IDEAL is based, is divided into six major 
activities. The activity uses 
the system description portion of IDEAL to 
construct a validated static system model. 
The Generate Performance Data Base activity 
uses the static system model as a guide to 
identify and collect the appropriate dynamic 
characteristics of the system. The Determine 
Simulation Ob iectives acitivty identifies the 
objectives, or goals, of building and 
exercising the simulation and establishes the 
criteria which will be used to evaluate 
system performance. The Construct Svs tem 
Simulation Model activity develops a dynamic 
model of simulation of the system. This 
activity is accomplished by translating the 
system information described in the static 
model and the dynamic characteristics into 
the simulation using the structures defined 
within the IDEAL simulation technique. This 
model defines the way in which the elements 
of the system interact to cause changes in the 
state of the system over time. The Exercise 
M o d e  I activity verifies and validates the 
dynamic model. Verification determines that 
154 
SVSTEY ---r 
SPECIFICATIONS 
SVSIEY 4 
T E C W I O U ~  
DtscnwTIo* 
nu 
RE 
ORIGINAL PAGE IS 
OF POOR QUALITY 
RECOYYENDATlONS 
r 1 
YISSION SCENARIO CUWOSL 
msCRLPANClES AYALVST 
ANALVST 
YODEL VALIDATED 
COWTROL 
hN FACTORS. 
PERFORY~NCE 
DATA BASES 
YECHANISY + 
ANALVST 
Figure 1. The Simulation Process 
the model executes on the computer as the 
modeler intended. Validation determines that 
the model is a reasonable representation of 
the system. The Run ExDeriments activity 
exercises the model on the computer and 
interprets the results. The results of this 
activity are either recommendations for 
additional analysis or a proposed solution to 
the problem definition. 
IDEAL is a step-wise technique in which 
each step maps into either the Describe 
System, the Generate Performance Data Base, 
or the Construct Systme Simulation Model 
activities. IDEAL uses a hierarchical, 
functional decomposition approach to 
describes the system in terms of a static 
system model. The approach provides the 
means for bounding the system of interest in 
terms of identifying what overall function the 
system is to perform, inputs to the system, 
outputs produced by the system, what 
controls and relationships are used to 
transform input into output, and what 
equipment, software, and humans are required 
to perform the transformation. Once the 
system has been bounded, the decomposition 
activity of IDEAL provides the structures 
necessary to gain a gradual, controlled 
graphic representation and understanding of 
the system (figure 2). 
MORE GENERAL 
MORE DETAILED 
Figure 2. Functional Decomposition Concept 
IDEAL uses a data base approach in which 
each function identified in the functional 
decomposition has an associated template for 
storing the dynamics data needed to provide a 
155 
complete operational description of that 
function. To develop the final simulation, 
IDEAL uses a network simulation approach 
which links the functions together and 
integrates dynamic data to form the 
operational representation of the system. 
The one feature which provides IDEAL with 
its power as an analysis tool is its utilization 
of a team effort. IDEAL accomplishes this 
integration through its knowledge engineering 
capability. The process of developing the 
functional model and the sytem performance 
characteristics is accomplished through an 
interviewing procedure during which the 
analyst collects information from system 
experts. The analyst then integrates the 
information and represents it in terms of the 
functional model and the system performance 
description. This integrated process helps to 
identify discrepencies among information 
sources as well as missing information about 
the system. This integrated information is 
then reviewed by the system experts in order 
to verify the analyst's understanding of the 
system, to add additional information, or to 
clarify conflicts among the experts. 
effort. The technical members of the team 
are provided the vehicle to have their 
information and analysis desires integrated 
into the simulation and to monitor and 
understand the simulation as it is being 
developed. The ultimate effects of developing 
a model using IDEAL are that the model will 
be understood and accepted by the team, will 
be a fully documented model, will be much 
easier to maintain and engance, and can be 
used as a training tool with respect to the 
operation of the system. 
IDEAL is a general purpose system 
analysis/design tool. It is applicable to any 
type of system and is beneficial even if only 
portions of the methodology are applied. 
There are natural breakpoints after the 
functional description and the Performance 
Data Base (PDB). At each breakpoint, a 
significant amount of new information will be 
available about the system. This may be 
enough information to answer the specified 
question. As more system insight is desired, 
the additional steps can be exercised or the 
current steps and be iterated. 
The methodology has been applied to a 
number of system types. Examples of these 
systems, automated message processing 
systems, data base design, manufacturing 
analysis, software design, and the integratin 
of existing simulations. 
This knowledge engineering approach is an applications have included man-machine 
in teract ive process which requi res 
communication among all members of the 
team which and causes IDEAL to be both a 
management tool and a technical tool (figure 
3). The management members of the team are 
provided the vehicle through which they can 
understand the simulation being developed as 
well as being able to plan, organize, control, 
and coordinate the resources required for the 
IDEAL 
MANAGEMENT / \ TECHNICAL 
TOOL TOOL 
DOCUMENTATON DOCUMENTATON - SYSTEMMATIZE 
DESKjN 
TWIN 
'UPROW WJINATE 
MAN-MACHINE SYSTEMS 
IDEAL has been used to develop a simulation 
of a Surface-to-Air Missile (SAM) system [l]. 
This effort required the integration of 
knowledge from three experts types. From 
the system operators, an expert system data 
base was developed by identifying tasks each 
operator performed, what information they 
used and how they used it, and how well they 
were able to perform their performance. 
From the hardware engineers, an 
understanding of the hardware capabilities 
was established. From other modeling and 
simulation experts, submodels of the same 
system were identified, evaluated, and 
assessed for integration into the IDEAL 
simulation. 
tE:z 
Figure 3. Project Integration Using IDEAL 
156 
This simulation was used to analyze the 
ability of the SAM crew to intercept threat 
aircraft that were operating under a variety 
of flight profiles and using a combination of 
countermeasure techniques. 
AUTOMATED MESSAGE PROCESSING 
SYSTEMS 
IDEAL has been used on a number of message 
processing systems. Two of the most in depth 
analysis were performed on the AE-9B High 
Speed Ring Bus (HSRB) Protocol [2] and the 
Central Processing Communication (CPCOM) 
system for the Precision Location and Strike 
System [3]. In both cases, the performance 
information was obtained from appropriate 
documents for the preliminary model. The 
system designers and the software developers 
were then incorporated into the IDEAL process 
to expand system understanding and perform 
model validation. 
The results of these analysis provided very 
useful. For CPCOM, it was found that major 
interface problems existed between the 
communications system and subcomponents 
that was linked to CPCOM. Also identified 
were some minor process timing problems 
that when changed caused substantial 
improvements in the processing capability. 
For the HSRB, most of the design 
parameters were verfified but one design 
parameter was determined to be less than 
optimal and significant recommendations 
were made as to the message from that would 
be best transmitted on the bus. 
DATA BASE DESIGN 
IDEAL was applied to the specification of a 
large data base design and for proving that 
the design would operate within the specified 
requirements [4]. This model was used to 
define, document, and communicate the 
original design and continue to be used to test 
additions before they are implemented. 
MANUFACTURING 
IDEAL has been applied to a variety of 
manufacturing capabilities. One model 
involved the analysis of an existing 
manufacturing facility and was aimed at 
identifying what processes were being 
accomplished, what information was common 
among the processes, what equipment and 
personnel were required to perform the 
functions, and how well each operator was 
being performed [5]. The goal of this effort 
was to develop a plan for upgrading the 
faci l i ty .  
A model was developed to analyze the 
process flow of an oil refinery. This model 
development involved the analysis of the flow 
rates, storage capabilities, and process 
monitoring requirements. The goal of the 
model was to recommend an approach for 
opt imiz ing the process moni tor ing 
capabilities of the refinery. 
SOFlWARE DESIGN 
IDEAL has been used on numerous program to 
either aid in the design of large, complex 
software systems or to analyze an existing 
system. One significant model involved the 
model ing and analysis of the software for the 
radar mode interleaving process of the B1-B 
aircraft [6].  The results of this simulation 
were used to identify a number of operational 
restrictions as well as some design errors. 
The results of the analysis were that 
problems were identified during the design 
stages and corrections were made without 
any major impact on the development 
schedule. 
CoNCLUSloNS 
IDEAL is a proven, general purpose 
methodology for modeling a wide variety of 
system types. IDEAL'S power lies in its 
capability to utilize knowledge engineering 
techniques to collect, integrate, and verify 
system information from a team of people. 
IDEAL provides the capabilities to build a 
system simulation in a top-down, structured 
manner, in a notation that communicates and 
documents the system, and in a form 
157 
executable on a computer. The graphical 
notation of the technique aids in the 
debugging, testing, modifications, and 
communication of the system. It allows the 
various system subfunctions to be modeled at 
different levels of detail in order to meet the 
needs of the problem statement and has the 
framework necessary to effectively integrate 
existing subsystem models. 
REFERENCES 
1. SofTech, Inc., "SAINT Performance 
Assessment Model of a SAM System 
(SPAMSS); Analyst Manual", August 1984. 
2. Cooper, W.M., "Using SAINT in Performance 
Analysis of Complex Hardware/Software 
Systems", Proceedinas of the IEEE 1985 
National Aeroseace a nd Electronics 
Conference INAECON], Dayton, Ohio. 
3. SofTech, Inc., "High Speed Ring Bus (HSRB) 
Protocol Analysis", June 1987. 
4. SofTech, Inc., This information is contained 
in a SofTech proprietary document. 
5. SofTech, Inc., This information is contained 
in a SofTech proprietary document. 
SofTech, Inc., This information is contained 
in a SofTech proprietary document. 
Evers, K.H., Bachert, R.F., "SADT: An 
Effective Tool For Knowledge Acquisition", 
Human Factors in Oraanizational Desian and 
Manaaement - II, August, 1986, Vancouver, 
B.C., Canada. 
Bachert, R.F., Evers, K.H., Hoyland, C.M., 8. 
Rolek, E.P., "IDEF/SAINT SAM Simulation: 
Hardware/Human submodels", Proceedinas 
gf the IEEE 1983 National Aeroseace and 
Electronics Co nference INAECON), Dayton, 
Ohio. 
9. Bachert, R.F., Evers, K.H., Santucci, P.R., 
"SADTEAINT: Large Scale Analysis 
Simulation Methodology", Proceedinas of 
jhe 1981 Winter Simulation Conference. 
158 


The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology: Capabilities and Applications

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server