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C4I Publication Abstracts
C3 Architectures

C3I-1001

Modeling Information Pull in the Copernicus Architecture
Using Colored Petri Nets

Authors: Didier M. Perdu, LCDR Cheryl L. Spohnholtz, USN, and Alexander H. Levis

The Copernicus Architecture is being developed to make information from all sources available to the warfighter at sea. This information need not be pushed automatically to the Battle Group; there is too much data and a large fraction of it is not relevant to the mission. On the other hand, relevant information requested by the warfighter should be received in time. Since Information Pull is central to the Copernicus Architecture, a Colored Petri Net model has been developed to investigate different modes of Information Pull: (1) Simple Pull, where the response to a query contains only the answer to the query and (2) Enhanced Pull, where the response to the query contains not only the answer to the query but also updates generated since the previous query that are relevant to the warfighter's mission. The study focuses on the load on the TADIXS Communications Network that connects the Battle Group to the CINC Command Complex ashore.

Proceedings of the 1994 Symposium on Command and Control Research and Decision Aids, Naval Postgraduate School, Monterey, California, June 21-23, 1994, pp. 115-129.

This work was carried out with support from the Basic Research Group of the Joint Director of Laboratories, through contract No. 19-940048-49 from Science Applications International Corp.

C3I-1002

Problems of Concurrency and Coordination In
Decision Making Organizations

Author: Hedy Z. Rashba

This report utilizes Colored Petri Nets (CPN) as supported by Design/CPN™ to revisit aspects of an earlier analysis of a two-person hierarchical organization. This project describes how Colored Petri Nets both (1) uncovered a need to address the various stages of decision making (as modeled by transitions in Petri Net methodology) when faced with large amounts of information requiring simultaneous evaluation (or having multiple enablements in Petri Net terminology), and (2) provided a means to represent these various stages of information. Colored Petri Nets, it is shown, can capture the example with a level of flexibility greater than that of earlier methodologies. This study also reveals that the underlying assumptions of Petri Net software can highlight different types of information processing.

This work was carried out with support provided in part by the Office of Naval Research under contract No. N00014-93-1-0912.

C3I-1003

The Impact of Organization Structure on Team Decision Making
Under Stress and Uncertainty

Authors: Paul E. Lehner and Alexander H. Levis

The objective of the research reported herein is to investigate coordination in team decision making. Particular focus is placed on the identification and characterization of variables that enhance coordination and enable teams to maintain coordinated actions under stressful conditions characteristic of tactical environments.

This work was carried out with support from the Office of Naval Research under contract No. N00014- 90-J-1680.

C3I-1004

Colored Invariants In Predicate/Transition Nets

Authors: Tong Zhang and Alexander H. Levis

The duality properties of Petri Nets are exploited in order to apply an algorithm for the calculation of colored S-invariants of Predicate Transition nets (Pr/T nets) to the calculation of the colored T-invariants.

This work was carried out with support from the Joint Director of Laboratories, Technical Panel on C3, through contract No. 19-940047-49 from Science Applications International Corp.

C3I-1005

Object Oriented Design Of Decision Making Organizations

Authors: Alexander H. Levis and Didier M. Perdu

Object oriented analysis and design can be applied to the problem of organizational design and the Colored Petri Net formalism, while the supporting software can be used effectively to implement the approach. Furthermore, existing results can be mapped easily in this paradigm. A dynamical model representation of the organization is obtained that can be analyzed using both Petri Net theory and the associated algorithms, as well as simulation.

Paper presented at the First Workshop in Command, Control, and Informations Systems Research, May 3-5, 1994, Eynsham Hall, Oxon, UK.

Also, appeared in The Science of Command and Control: Part III, Coping with Change, A. H. Levis and I. S. Levis, eds., AFCEA International Press, Fairfax, VA, 1994.

This work was carried out with support from the Office of Naval Research under contract No. N00014- 93-1-0912.

C3I-1006

Information Transfer Effectiveness of Different Modes
Of Information Pull in the Copernicus Architecture

Authors: Didier M. Perdu- C3I Center, George Mason University,Fairfax, VA 22030; Susan L. Hearold - NCCOSC/RDT&E, Code 405, San Diego, CA; Alexander H. Levis - C3I Center, George Mason University, Fairfax, VA 22030

The Copernicus Architecture is being developed to make information from all sources available to the warfighter at sea. Since all information cannot be pushed automatically, some information is transmitted only on request. The effectiveness of an information transfer mode is related to the extent to which the ashore information needed by the commanders is received afloat in a timely manner and actually used. A Colored Petri Net model of the Copernicus Architecture has been developed to study the effectiveness of two modes of information pull: (1) Simple Pull, where the response to a query contains only the answer to the query, and (2) Enhanced Pull, where the response to the query contains not only the answer to the query but also updates generated since the previous query that are relevant to the warfighter's mission. Results show that Simple Pull is effective when there are enough communications resources but ineffective when they are limited. Enhanced Pull, in spite of being less effective, is more robust in handling changes in the availability of communications resources.

This work was carried out with support from the Joint Director of Laboratories, Technical Panel on C3, through contract No. 19-940047-49 from Science Applications International Corp.

Paper presented at the First Workshop in Command, Control, and Informations Systems Research, May 3-5, 1994, Eynsham Hall, Oxon, UK.

Also, appeared in The Science of Command and Control: Part III, Coping with Change, A. H. Levis and I. S. Levis, eds., AFCEA International Press, Fairfax, VA, 1994.

C3I-1007

A Systems Engineering Approach
to Information Architecture Design

Authors: Alexander H. Levis and Didier M. Perdu

Structured analysis and object oriented approaches to information system requirements analysis and design are discussed. It is argued that the design of an information architecture is an essential step in an uncertain environment, when the rates of external and internal change and the rate of technological change are high. Executable models based on Colored Petri Nets enhance the object oriented approach for use in systems engineering.

Paper presented at the 1994 IFAC Symposium on Integrated Systems Engineering. Baden-Baden, Germany, Sept. 27-29, 1994.

This work was carried out with support from the Joint Director of Laboratories, Technical Panel on C3, through contract No. 19-940047-49 from Science Applications International Corp.

C3I-1008

Validation and Verification of Decision Making Rules

Author: Abbas Kazim Zaidi

A methodology for the validation and verification of rule bases is proposed. The methodology addresses the general problem of detecting problematic and erroneous cases in a set of rules, and overcomes the limitations of the existing techniques and methods. The methodology requires that the rules be expressed as statements in either Propositional or First-Order Predicate Calculus. The definition of decision rules in formal logic makes the problem general enough to encompass a whole variety of rule bases, and also provides an analytical base for defining problematic and erroneous cases. Based on results from formal logic, a comprehensive set of logically erroneous cases is identified. The methodology is based on viewing a rule base as an organization of information that flows from one process (rule) to another. Since Petri Nets provide a powerful modeling and analysis tool for information flow structures, the methodology transforms a set of decision rules into an equivalent Petri Net representation. Once a rule base is transformed into a Petri Net, the solution to the problem becomes a direct application of well- established analytical tools of Petri Net theory. The validation and verification of the rule base is done by first exploiting the structural properties of the Petri Net representation by S-invariant or Trap/Deadlock analysis and then by constructing the Occurrence graph directly from the Petri Net representation. The approach evaluates the static and dynamic properties of the graph to reveal patterns of Petri Net structures that correspond to the problematic cases. The tools and techniques presented in this thesis are based on theory and are supported by software tools.

This work was carried out with support from the Office of Naval Research under contracts No. N00014- 90-J-1680 and No. N00014-93-1-0912.

C3I-1009

Performance Evaluation of C3I Architectures

Authors: Zhenji Jin, Alexander H. Levis, and Lee Wagenhals

Two methodologies for deriving C3I system architectures are described and compared: structured analysis and object oriented analysis. Both methodologies lead to executable models in Petri Net form that can be used for analysis and evaluation. An existing algorithm for identifying deadlocks and traps in a restricted class of Petri Nets has been generalized so that it can be used for any ordinary Petri Net representation of a C3I architecture. Examples based on the Copernicus architecture illustrate the approaches and results. Finally, the Air Tasking Order problem faced by a Joint Forces Air Component Commander is described as a first step toward the design of architectures to support it.

This work was carried out with support from the Joint Director of Laboratories, Technical Panel on C3, through contract No. 19-940047-49 from Science Applications International Corp.

C3I-1010

Validation and Verification of Decision Making Rules

Authors: Abbas K. Zaidi and Alexander H. Levis

A methodology for the validation and verification of decision making rules is proposed. The methodology addresses the general problem of detecting problematic cases in a set of rules. The rules are expressed as statements in formal logic. The definition of decision rules in formal logic makes the problem general in terms of application domains, and also provides an analytical base for defining errors. The approach is based on viewing a rule base as an organization of information that flows from one process (rule) to another. Since Petri Nets provide a powerful modeling and analysis tool for information flow structures, the methodology transforms a set of decision rules into an equivalent Petri Net representation. The static and dynamic properties of the graph are shown to reveal patterns of Petri Net structures that correspond to the problematic cases. The tools and techniques presented in this paper are based on theory and are supported by software tools.

Paper to be presented at the 6th IFAC/IFIP/IFORS/IEA Symposium on Analysis, Design and Evaluation of Man-Machine Systems, M.I.T., Cambridge, MA, June 27-29, 1995.

This work was carried out with support from the Office of Naval Research under contracts No. N00014- 90-J-1680 and No. N00014-93-1-0912.

C3I-1011

On Verifying Inferences in an Influence Net

Authors: Abbas K. Zaidi and Alexander H. Levis

A methodology for the verification of inferences obtained from an influence net is presented. The methodology is based on transforming an influence net into an equivalent Petri net representation. The application of well-known analytical tools of the Petri net theory is shown to reveal chains of inferences in the influence net that are problematic and possibly erroneous. The methodology is an extension of the results presented in Zaidi and Levis (1995) for the validation and verification of decision making rules. The tools and techniques presented in this paper are based on theory and are supported by software tools.

Paper to be presented at the 1995 Symposium on Command and Control Research and Technology, National Defense University, Washington, DC, June 19-23, 1995.

This work was carried out with support from Science Applications International Corp. (SAIC) under sub- contract number 26-940079-80.

C3I-1012

Modeling The Functionality Of The C2 Element
of the National Missile Defense System

Authors: Dennis M. Buede, Didier Perdu, and Lee W. Wagenhals

This paper reports on research being conducted to analyze the functionality of the C2 element of the National Missile Defense (NMD) system in support of the Army's Operational Evaluation Command. As part of this effort we are using three of the more advanced functional modeling techniques: Integrated Computer Aided Manufacturing (ICAM) Definition Language (IDEF0), Behavior Diagrams, and Colored Petri Nets. In this paper we compare and contrast the functional modeling capabilities of the three techniques in terms of parameters such as understandability of the representation, and correctness of the dynamic process. In order to perform this comparison we will examine the ability of the functional models to represent particularly difficult issues of the C2 element of NMD such as concurrency of operation, replication of identical activities caused by multiple instances of threats or friendly resources, and monitoring processes needed to achieve redundancy in case of failure.

This research was funded under contract MDA 903-88-0019 as a subcontract from PRC, Inc. from the U.S. Army Operational Evaluation Command. Article appeared in Proceedings of the Symposium on Command and Control Research 1993, National Defense University, Fort Lesley J. McNair, Washington D.C., June, 1993.