Lee W. Wagenhals

C4ISR architectures : II. A Structured Analysis approach for Architecture design

A Structured Analysis based process for developing C4ISR architectures is presented. The process demonstrates the feasibility of developing architecture descriptions that conform to the C4ISR Architecture Framework based on the Structured Analysis paradigm that underlies the concepts and definitions in the Framework. Furthermore, the process incorporates the derivation of an executable model that can reveal the logical, behavioral, and performance characteristics of the architecture. The complete process is illustrated through an example involving the insertion of a new technology in a large legacy system.

Modeling effects-based operations in support of war games

The problem of planning, executing and assessing Effects-Based Operations (EBO) requires the synthesis of a number of modeling approaches. A prototype system to assist in developing Courses of Action (COAs) for Effects-Based operations and evaluating them in terms of the probability of achieving the desired effects has been developed and is called CAESAR II/EB. Two of the key components of the system are: (a) an Influence net modeler such as the Campaign Assessment Tool (CAT) developed at AFRL/IF, and (b) an executable model generator and simulator based on the software implementation of Colored Petri nets called Design/CPN. The executable model, names COA/EB, is used to simulate the COAs and collect data on Measures of Performance (MOPs). One particular output is the probability of achieving the desired affect as a function of time. Probability profiles can be compared to determine the more effective COAs. This version of CAESAR II/EB was used successfully in August 2000 at the Naval War College in the war game Global 2000. Experiences with building and using the models both prior to the war game and during the war game to answer tropical questions as they arose are described.

Course of Action Analysis in a Cultural Landscape Using Influence Nets

Since 1992 the nature of military operations has changed. The type of objectives that the military has to address has expanded well beyond those of traditional major combat operations. As military operations become other than conventional war - whether against transnational terrorist threats or conducting stabilization operations - the need to broaden the focus of models that support effects based planning and operations has become critical. One major present weakness is the absence of socio-cultural attributes in the models used for course of action selection and effects based planning. This paper illustrates an approach that enables analysts to evaluate a complex situation in which an adversary is embedded in a society from which it is receiving support. The paper describes a layered modeling approach that enables the analysts to examine and explain how actions of the military and other entities may results in desired or undesired effects, both on the adversary and on the population as a whole, and shows several techniques for comparing contemplated courses of action

Toward executable architectures to support evaluation

It has been 10 years since the Department of Defense (DoD) first issued its Architecture Framework (DODAF). In the past we have shown that it is possible to take an architecture description that conforms to DODAF and convert it to an executable model to support rigorous evaluation. We now have a proof of concept that demonstrates the feasibility of making the conversion to the executable model automatically. Implementing this automatic translation will enable architects to apply more rigorous analysis and evaluation approaches to complex architecture evaluation problems such as determining the agility in particular architecture designs that are based on information sharing. This paper describes the issues in automatic translation of architectures that are based on either the Structured Analysis or the Object Oriented approaches into the rigorous executable modeling language of Colored Petri Nets. The paper includes a proof of concept case study and briefly discusses the advantages of using the executable model in evaluating logical, behavioral, and performance aspects of the architecture.

Creating executable models of influence nets with colored Petri nets

This paper describes a methodology for converting an influence net to a dynamic executable model, implemented using the colored Petri net (CPN) formalism and tools, so that it can be used to assess the impact of a set of controllable events or actions on outcomes of interest; specifically, assess the impact of various sequences and timing of those actionable events. With this methodology, alternative courses of action, first defined using influence nets, which are static equilibrium models, can be refined by adding sequence and timing information for analysis and comparison. The techniques developed offer a means to integrate intelligence and operational planning models to improve course of action development. The paper includes a description of the automated algorithms that convert an influence net to a colored Petri net and illustrates how that model can be used for the analysis of alternative courses of action.

Planning temporal events using point-interval logic

The paper presents a temporal logic and its application to planning time-critical missions. An extended version of the Point-Interval Logic (PIL) is presented that incorporates both point and interval descriptions of time. The points and intervals in this formalism represent time stamps and time delays, respectively, associated with events/activities in a mission as constraints on or as resultants of a planning process. The lexicon of the logic offers the flexibility of qualitative and/or quantitative descriptions of temporal relationships between points and intervals of a system. The provision for qualitative temporal relationships makes the approach suitable for situations where all the required quantitative information may not be available to planners. A graph-based approach, called the Point Graph (PG) methodology, is shown to implement the axiomatic system of PIL by transforming the temporal specifications into Point Graphs. A temporal inference engine uses the Point Graph representation to infer and verify the feasibility of temporal relations among system intervals/points. The paper demonstrates the application of PIL and its inference engine to a mission-planning problem.

Meta-modeling the Cultural Behavior Using Timed Influence Nets

A process that can be used to assist analysts in developing domain specific Timed Influence Nets (TIN) is presented. The process can be used to represent knowledge about a situation that includes descriptions of cultural behaviors and actions that may influence such behaviors. One of the main challenges in using TINs has been the difficulty in formulating them. Many Subject Matter Experts have difficulty in expressing their knowledge in the TIN representation. The ontology based meta modeling approach described in this paper provides potential assistance to these modelers so that they can quickly create new models for new situations and thus can spend more time doing analysis. The paper describes the theoretic concepts used and a process that leads to an automated TIN generation. A simple example is provided to illustrate the technique.

ANALYZING DYNAMIC BEHAVIOR OF LARGE-SCALE SYSTEMS THROUGH MODEL TRANSFORMATION

This paper describes model transformation for analyzing dynamic behavior of large-scale systems. The Unified Modeling Language (UML) based system model is transformed into the Colored Petri Nets (CPN) model, which is used for analyzing the scenarios of the use cases of a system and checking freedom of system deadlock at an early stage of software development. The CPN model that is executable is hierarchically structured on the basis of the functional decomposition of a large-scale system. The UML-based system model consisting of the use case model, class model and collaboration model is not executable so that the dynamic behavior of the system cannot be analyzed until implementation of the system. However, the UML-based system model has no hierarchical structure to be transformed into the hierarchical CPN model as well. The discrepancies of dynamic and structural views in the two models are resolved by transformation of the UML model into the layered, executable CPN model with three layers — the use case layer, object layer and operation layer. The model transformation is carried out using relationships among the use case model, class model, and collaboration model of the UML. With the executable CPN model transformed, the dynamic properties of the system are analyzed using the simulation technique, occurrence graph, and state space report provided by the Design/CPN tool. The approach in this paper is validated through two case studies — the gas station system and the distributed factory automation system.

Building and analyzing timed influence net models with internet-enabled pythia

The most recent client-server version of Pythia modeling software is presented. Pythia is a software implementation of a Bayesian Net framework and is used for course of action development, evaluation, and selection in the context of effects-based planning. A new version, Pythia 1.5, is a part of a larger suite of tools for behavioral influence analysis, brought into the state-of-the-art client-server computing environment. This server application for multi-user and multiprocess computing relies on the Citrix Presentation Server for integration, security and maintenance. While Pythias process is run on a server, the input/output services are controlled and displayed through a client PC. Example use of Pythia is illustrated through its application to a suppression of IED activity in an Iraqi province. This case study demonstrates how analysts can create executable (probabilistic) models that link potential actions to effects, based on knowledge about the cultural and social environment. Both the tool and the process for creating and analyzing the model are described as well as the benefits of using the new server based version of the tool.

Multi-modeling of adversary behaviors

Models developed using different modeling languages but the same data provide different insights of the human terrain. Interoperation of such models, i.e., multi-modeling, can produce a more robust modeling and simulation capability to support operational commanders or intelligence analysts. The C2 Wind Tunnel is a platform that enables multi-modeling and the conduct of simulations and computational experiments. However, to establish that the interoperation of the models is valid, meta-modeling analysis is required. An approach using concept maps is described.