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Papers
 Young
Jun Son, Sanjay B. Joshi, Richard A. Wysk, and Jeffrey S. Smith,
Simulation Based Shop Floor Control, Journal of Manufacturing
Systems, 21 (5), December 2002, 380 - 394. pdf
Young
Jun Son, Hector Rodriguez-Rivera, and Richard A. Wysk, A
Multi-pass Simulation-based, Real-time Scheduling and Shop Floor
Control System, Transactions of the Society for Computer
Simulation International, 16 (4), Dec. 1999, 159 - 172.
pdf
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 Automatic Generation of Simulation
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To reduce the high cost of control software development and
maintenance, research has been conducted on rapid realization of
a simulation-based control (SBC) system for a discrete part
manufacturing system. The above figure illustrates an approach
to develop an SBC involving the automatic generation of an
execution model and a simulation model from a resource model.
The resource model contains information describing all of the
individual resources in a facility as well as the necessary
interactions between these resources.
A methodology (using a series of rules) to automate
execution model generation from a resource model has been
developed. Given an MPSG execution model, Smith and Joshi
(1993) developed software tools for automatically generating
essential portion (a set of C++ files) of the controller (e.g.
BigE or equipment level controller). A methodology to automate
simulation model generation from a resource model and an
execution model has also been developed.
The shop floor resource model
provides much of the static information for the simulation
model; while a shop level execution model (BigE MPSG in this
case) provides much of the dynamic information required by the
simulation model.
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Papers
Young
Jun-Son, Richard A. Wysk, and Albert T. Jones,
Simulation Based Shop Floor Control:
Formal Model, Model Generation and Control Interface,
IIE Transactions on Design and Manufacturing, 35 (1),
January 2003, 29 - 48 (also introduced in IIE Solutions
magazine). pdf
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Distributed Simulation: Integration of Legacy
Simulations
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Applying discrete event simulation to systems of systems (e.g.
supply chain) leads naturally to federations of distributed,
heterogeneous simulation models. The existence of legacy
subsystem models is one driving force for federating the
systems; another is good software engineering practice. The
result is an analytic tool that may be executed on a single
processor or distributed across multiple computing platforms,
perhaps over a wide-area network, leading to a corresponding
technical requirement for system-wide synchronization between
the federated models. Synchronization theory and methods is one
focus of the proposed research. The other is a complementary
focus on problem and model attributes that impact model
development and computational performance under alternative
synchronization approaches.
In distributed simulations, local, federate-specific,
simulation clocks must be synchronized so that events in each
federate execute in the correct manner, thereby producing
correct simulation results. Synchronization is a complex IT
problem that has not satisfactorily resolved either
theoretically or in practice. Our objective is to understand
the synchronization requirements associated with “system of
systems” simulations, to develop and adapt a range of
synchronization schemes, and explore the potential for novel
simulation support technology – a static federation optimizer
that selects the best configuration from a set of time
management methods, and a dynamic federation optimizer that
adapts the time management scheme on the fly. To achieve this,
we exploit the existing computational infrastructure provided by
the High Level Architecture (HLA) and Runtime Infrastructure (RTI)
by the OMG (IEEE standard) (see the above figure). We also
identify key federation attributes that impact the computational
efficiency of distributed federates. We develop methods and
protocols that take advantage of federation attributes so as to
best structure (optimize) the execution of the federated
simulation. We use Operations Research and Automata principles
to determine if this optimized federation can be automatically
configured and deployed. We finally investigate the generic
application of these models by developing application examples
in various and disparate model domains.
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Papers
Jayendran
Venkateswaran and Young Jun Son, Design and Development of a
Prototype Distributed Simulation for Evaluation of Supply
Chains, International Journal of Industrial Engineering,
11 (2), June 2004, 151 - 160. pdf
S.
Misra, J. Venkateswaran, and Y. Son, Framework for Adaptive Time
Synchronization Method for Integration of Distributed,
Heterogeneous, Supply Chain Simulations, Proceedings of The
American Society of Engineering Management Conference,
St Louis, USA, October 15-18,
2003. pdf
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Hierarchical Production Planning using
Distributed, Hybrid Simulation
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Multi-plant production planning problem deals with the
determination of type and quantity of products to produce at the
plants over multiple time periods. Hierarchical production
planning provides a formal bridge between long-term plans and
short-term schedules. A hybrid simulation-based hierarchical
production planning architecture consisting of system dynamics
(SD) components for the enterprise level planning and discrete
event simulation (DES) components for the shop level scheduling
is presented. The architecture consists of the Optimizer,
Performance Monitor and Simulator modules at each decision
level. The Optimizers select the optimal set of control
parameters based on the estimated behaviour of the system. The
enterprise level simulator (SD model) and shop level simulator
(DES model) interact with each other to evaluate the plan.
Feedback control loops are employed at each level to monitor the
performance and update the control parameters. Functional and
process models of the proposed architecture are specified using
IDEF. The internal mechanisms of the modules are also described.
The modules are interfaced using High Level Architecture (HLA).
Experimental results from a multi-product multi-facility
manufacturing enterprise demonstrate the potential of the
proposed approach.
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Papers
J.
Venkateswaran, Y. Son, and A. Jones, Hierarchical Production
Planning using A Hybrid System Dynamic and Discrete Event
Simulation Architecture, Proceedings of the Winter Simulation
Conference 2004, Washington D.C., USA, December 5-8, 2004. pdf
Jayendran
Venkateswaran and Young Jun Son, August 2004, Hybrid System
Dynamic -- Discrete Event Simulation based Architecture for
Hierarchical Production Planning,
submitted to International Journal of Production
Research.
Jayendran
Venkateswaran, Young Jun Son, Albert T. Jones, Jason Min,
September 2004, Hierarchical Production Planning in VMI Supply
Chain Using a System Dynamic-Discrete Event Simulation
Architecture, submitted to
International Journal of Simulation and Process Modeling.
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Penalty Function-based Real-time Shop Floor
Control
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Although several hybrid shop floor control architectures have
been proposed in the literature, varying degrees of autonomy of
subordinate controllers and their effects on supervisory level
performance have not been studied. We create a new hybrid
control architecture with two levels, where the autonomy of
subordinate agents changes adaptively. The key feature is the
penalty function, which represents the degree of negative impact
that changing the original schedule will have on performance.
When a disturbance occurs, the disturbance agent invokes
rescheduling at the appropriate level depending on the threshold
disturbance level. The subordinate agents execute tasks based
on the schedule from the supervisory agent in the absence of
disturbances; or else revise the original schedule optimally
with regard to both the supervisory level performance (via
penalty function) and the disturbance. We study math
programming formulations, quantitative metrics to indicate the
disturbance level and the levels of autonomy.
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Papers
X.
Zhao and Y. Son, Penalty Function-based Hybrid Shop Floor
Control System, Proceedings of the Annual Industrial
Engineering Research Conference 2004, Houston, USA, May
15-19, 2004. pdf
Xiaobing
Zhao and Young-Jun Son, April 2004, Penalty Function based Two
Level Hybrid Shop Floor Control System,
submitted to IEEE
Transactions on Automation Science and Engineering.
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Modeling of Human Decision-making
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The objectives of our research are 1) to develop a human
operator model in a complex system and 2) to develop a software
platform in which hybrid decision models are easily integrated
into one automated package.
To achieve the first object, we employ BDI (three components of
mental state: belief, desire, and intention) agent framework to
model a human operator (see Figure above). The proposed human
operator model is composed of four components, including 1)
cognitive processor (in charge of belief), 2) perceptual
processor (in charge of desire), 3) reasoner (in charge of
intention and decision-making), and 4) commander. Furthermore,
a human emotion set, representing the impact of emotion factors
(fatigue, stress, and anger) on reasoning, is also considered in
the proposed research. In this work, belief, desire, and
intention are represented in First Order Predicate Logic, and
the intention (planning) problems are resolved using STRIPS.
The proposed model is implemented and tested in JACK.
The achieve the second object, we employ U.S.
Department of Defense High Level Architecture’s (HLA) RunTime
Infrastructure (RTI) to integrate various decision theoretic
models with hybrid simulation and optimisation models. In the
current implementation, those modules that are linked
into one automated, integrated package include 1) Arena discrete
event simulator, 2) Powersim system dynamic simulator, 3) AMPL
and MINOS nonlinear optimization solver, and 4) custom developed
meta-heuristics. Currently, we are enhancing the platform to
integrate human interactions and other decision aids and models.
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Papers
X.
Zhao and Y. Son, Modeling Human Operator in Manufacturing
Systems using BDI Agent Paradigm, Working Paper at The
University of Arizona, August, 2004.
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Development of Library of
Simulation Components
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We
propose development of libraries of formal, neutral models of
simulation components. The availability of such libraries would
simplify the generation of simulation models, enable reuse of
existing models construction of complicated models from simpler
ones, and speed Internet-based simulation services. The result
would be a dramatic increase in the use of simulation for
decision-making and control in manufacturing. In this work, we
describe a collection of formal, neutral models for a
discrete-event simulation of the flow of jobs through a job
shop, where the simulation executes jobs based on a pre-provided
schedule. We then derive a database structure from these
formal models and discuss the population of that database with
the data entries for a sample job shop. We then examine the
translators we developed to go from the neutral representation
of the simulation components to the representation required by
Arena. Finally, we compare this routing aspect of translator to
the routing aspects of a translator we built for ProModel.
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Papers
Young
Jun Son, Albert T. Jones, and Richard A. Wysk, Component Based
Simulation Modeling from Neutral Component Libraries,
Computers & Industrial Engineering, 45(1), May 2003, 141 -
165. pdf
A.
Rathore, J. Venkateswaran, and Y. Son, Survey of E-Business
Standardization Initiatives and Requirements Analysis and IDEF
Models for Generic Supply Chain Simulation, Working Paper at
The University of Arizona, August, 2004.
pdf
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