Agent-Based Modeling: Methods and Techniques for Scheduling Industrial Machine Operation

@ IJTSRD | Available Online @ www.ijtsrd.com
ISSN No: 2456
International
Research
Agent-Based Modeling: Methods and Techniques for
Scheduling Industrial Machine Operation
Chiagunye Tochukwu
Department of Computer
Engineering, Michael Okpara
University of Agriculture,
Umudike
ABSTRACT
Owing to its impact on the industrial economy, job
shop scheduler and controller are vital algorithms for
modern manufacturing processes. Hence a production
scheduling and control that performs reactive (not
deterministic) scheduling and can make decision
which job to process next based solely on its partial
(not central) view of the plant becomes necessary.
This requirement puts the problem in the class of
agent based model (ABM). Hence this work adopt
an alternative view on job-shop scheduling probl
where each resource is equipped with adaptive agent
that, independent of other agents makes job
dispatching decision based on its local view of the
plant. A combination of Markov Chain instruments
and agent oriented analysis is used in the analysis of
the proposed agent based model (ABM) for the job
shop scheduling problem. The Markov Chain
approach allows a rigorous analysis of the ABM. It
provides a general framework of aggregation in agent
based and related computational models by
use of Markov Chain aggregation and lumpability
theory in order to link the micro and the macro level
of observation. Simulated annealing technique is used
for carrying out the optimization modeling for the
ABM.
Keywords: Agent-Based, Scheduling
Machine Operation, Markov Chain
1.1 Introduction
In the United States alone, there are over 40
factories producing metal-fabricated parts [
@ IJTSRD | Available Online @ www.ijtsrd.com | Volume – 2 | Issue – 1 | Nov-Dec 2017
ISSN No: 2456 - 6470 | www.ijtsrd.com | Volume
International Journal of Trend in Scientific
Research and Development (IJTSRD)
International Open Access Journal
Based Modeling: Methods and Techniques for
Inyiama Hyacinth
Department of Electronic and
Computer Engineering, Nnamdi
Azikiwe University, Awka
Aguodoh Patrick
Department
Engineerin
Owing to its impact on the industrial economy, job
shop scheduler and controller are vital algorithms for
Hence a production
deterministic) scheduling and can make decision on
nt becomes necessary.
agent based model (ABM). Hence this work adopts
shop scheduling problem
plant. A combination of Markov Chain instruments
and agent oriented analysis is used in the analysis of
he proposed agent based model (ABM) for the job
shop scheduling problem. The Markov Chain
approach allows a rigorous analysis of the ABM. It
provides a general framework of aggregation in agent-
based and related computational models by making
ov Chain aggregation and lumpability
theory in order to link the micro and the macro level
Simulated annealing technique is used
for carrying out the optimization modeling for the
Scheduling, Industry,
In the United States alone, there are over 40,000
fabricated parts [1]. These
parts end up in a wide variety of products sold in the
US and elsewhere. These factories employ r
over 3 million people and ship close to $ 7 billion
worth of products every year. The vast majority of
these factories are called “job shops”, meaning that
the flow of raw and unfinished goods through them is
completely random. Over the years, the
performance of these job shops have been the focus of
considerable attention in Operations Research (OR)
literature.
Manufacturing industries are facing a growing and
rapid change. Major trends like globalization,
customer orientation and increasing market dynamics
lead to a shift in both managerial and manufacturing
principles: enterprises have to become more flexible,
open, fast, effective, self-organized, decentralized, to
sum it up: agile [2]. Manufacturing serves as a basic
function for any agile enterprise. The call for agility
challenges the shop floor with several problems.
With an increasing occurrence of changes and
dominating customer demand, management of
manufacturing processes and the coordination of the
multifarious resources, i.e., machines, materials,
information, knowledge and humans, becomes a core
task of shop floor scheduling and control algorithm
[2].
An important issue in a manufacturing environment is
the improvement of resource utilization. A classical
way of achieving improved resource utilization is by
using scheduling algorithms [3
[4] scheduling is concerned with the problem of
Dec 2017 Page: 465
| www.ijtsrd.com | Volume - 2 | Issue – 1
Scientific
(IJTSRD)
International Open Access Journal
Based Modeling: Methods and Techniques for
Aguodoh Patrick
epartment of Computer
Engineerin, Michael Okpara
Umudike
ty of products sold in the
US and elsewhere. These factories employ roughly
over 3 million people and ship close to $ 7 billion
worth of products every year. The vast majority of
these factories are called “job shops”, meaning that
the flow of raw and unfinished goods through them is
Over the years, the behavior and
performance of these job shops have been the focus of
considerable attention in Operations Research (OR)
Manufacturing industries are facing a growing and
rapid change. Major trends like globalization,
reasing market dynamics
lead to a shift in both managerial and manufacturing
principles: enterprises have to become more flexible,
organized, decentralized, to
]. Manufacturing serves as a basic
any agile enterprise. The call for agility
challenges the shop floor with several problems.
With an increasing occurrence of changes and
dominating customer demand, management of
manufacturing processes and the coordination of the
i.e., machines, materials,
information, knowledge and humans, becomes a core
task of shop floor scheduling and control algorithm
An important issue in a manufacturing environment is
the improvement of resource utilization. A classical
ing improved resource utilization is by
3]. As defined by Baker
scheduling is concerned with the problem of

International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
@ IJTSRD | Available Online @ www.ijtsrd.com | Volume – 2 | Issue – 1 | Nov-Dec 2017 Page: 466
assigning a set of jobs to resources over a period of
time. Effective scheduling plays a very important role
in today’s competitive manufacturing environment.
Performance Criteria such as machine utilization,
manufacturing lead times, inventory costs, meeting
due dates, customer satisfaction, and quality of
products are all dependent on how efficiently the jobs
are scheduled in the system [5]. Hence, it becomes
increasingly important to develop effective scheduling
approaches that help in achieving the desired
objectives.
The scheduling and planning of production order have
an important role in the manufacturing system. The
diversity of products, increased number of orders, the
increased number and size of workshops and
expansion of factories have made the issue of
scheduling production orders more complicated,
hence the traditional methods of optimization are
unable to solve them [6][7].
As can be deduced from these techniques, most
approaches to job-shop scheduling assume complete
task knowledge and search for a centralized solution.
These techniques typically do not scale with problems
size, suffering from an exponential increase in
computation time. The centralized view of the plant
coupled with the deterministic algorithms
characteristic of these schedulers do not allow the
manufacturing processes to adjust the schedule (using
local knowledge) to accommodate disturbances such
as machine breakdowns. Hence a production
deterministic) scheduling and can make decision on
(not central) view of the plant becomes necessary.
agent based model (ABM). Hence this work adopts
an alternative view on job-shop scheduling problem
plant.
2.0 Literature Review
Scheduling, understood to be an important tool for
manufacturing and engineering, has a major impact on
productivity of a process [8]. In manufacturing, the
purpose of scheduling is to minimize the production
time and cost, by telling a production facility what to
make with which staff, and on which machine. Cited
publications argued that agent-based modeling is used
because only agent-based model can explicitly
incorporate the complexity arising from individual
behavior and interactions that exist in the real-world.
[9] contributed to interweaving Markov Chains and
agent-based modeling. [10] worked on and
represented ten well-known simulation models as a
time homogenous Markov Chain. The author’s main
idea is the formulation of the system configuration as
the state space of the Markov Chain.
[11] formulated the JSP using integer programming.
This technique involved assuming that each job
consist of m operations and must pass through each
machine exactly once. All machines are available at
time zero. Furthermore, the total number of sub lots
is given and consistent sub lot sizes are considered.
Concerning the limitation of this technique, [12]
pointed out that the problem formulation used does
not recognize the physical environment of the shop
floor domains where interference not only leads to
readjustment of schedules but also imposes physical
conditions to minimize them. Still, difficulties in the
formulation of material flow constraints as
mathematical inequalities and the development of
generalized software solutions have limited the use of
these approaches.
Furthermore, although efficient bonding and pruning
procedures have been developed to speed up the
search, this is still a very computational intensive
procedure for solving large scheduling problem. [13]
proposed a methodology for solving the job shop
problem based on the decomposition of mathematical
programming problems that used both Benders-type
[14] and Dantzig/wolfe-type [15] decompositions.
The methodology was part of closed-loop, real-time,
two-level hierarchical shop floor control system. The
top-level scheduler (i.e., the supremal) specified the
earliest start time and the latest finish time for each
job. The lower level scheduling modules (i.e., the
infimals) would define these limit times for each job
by detailed sequencing of all operations. A multi-
criteria objective function was specified that include
tardiness, throughput, and process utilization cost.
The limitations of this methodology stem from the
inherent stochastic nature of job shops and the
presence of multiple, but often conflicting, objectives
made it difficult to express the coupling constraints
using exact mathematical relationships. This made the
schedule not to converge. Furthermore the rigid

centralization of the scheduler made it not able to
adjust to disturbances at the shop floor.
[16] evaluated the use of MRP or MRP-11 to create a
medium-range scheduler. MRP system’s major
disadvantages are not only rigidity and the lack of
feedback from the shop floor, but also the tremendous
amount of data that have to be entered in the bill of
materials and the fact that the model of the
manufacturing system and its capacity are excessively
simple. As can be deduced from these techniques,
most approaches to tackle job-shop scheduling
problem assume complete task knowledge and search
for a centralized solution. These techniques typically
do not scale with problem size, suffering from an
exponential increase in computation time. The
centralized view of the plant coupled with the
deterministic algorithms characteristic of these
schedulers do not allow the manufacturing processes
to adjust the schedule (using local knowledge) to
accommodate disturbances such as machine break
downs. Hence a production scheduling and control
that performs reactive (not deterministic) scheduling
and can make decision on which job to process next
based solely on its partial (not central) view of the
plant becomes necessary. This requirement puts the
problem in the class of agent based model (ABM).
Hence this work adopts an alternative view on job
shop scheduling problem where each resource is
equipped with adaptive agent that independent of
other agents, makes job dispatching decision based on
its local view of the plant.
3.0 Research methodology:
A combination of Markov Chain instruments and
agent oriented analysis is used in the analysis of the
proposed agent based model (ABM) for the job shop
scheduling problem. The Markov Chain approach
allows a rigorous analysis of the ABM. It provides a
general framework of aggregation in agent-based and
related computational models by making use of
Markov Chain aggregation and lumpability theory in
order to link the micro and the macro level of
observation.
The starting point is a Microscopic Markov Chain
description of the dynamical process in complete
correspondence with the dynamic behavior of the
agent model which is obtained by considering the set
of all possible agent configurations as the state space
of a huge Markov Chain. This is referred to as micro
chain. The explicit micro formulation enables the
application of the theory of Markov Chain
aggregation-namely, lumpability-in order to reduce
the state space of the micro chain and relate
microscopic deceptions to a macroscopic formulation
of interest.
Simulated annealing technique is used for carrying
out the optimization modeling for the ABM. Some of
the conditions for asymptotic convergence, as for
instance, the infinite length of Markov Chains, cannot
be met in practice [1]. Hence, in any finite
implementation, choice have to be made with respect
to the parameter:
- The length of the Markov Chain
- The initial value of the control parameter
- The decrement rule of the control parameter
- The final value of the control parameter
Such a choice is usually referred to as cooling
scheduler or an annealing schedule [2], hence the use
of simulated annealing for the global optimization of
the ABM for the proposed JSP.

3.2 Proposed System
Fig. 1: Block Diagram of the Proposed ABM Framework for Solving the JSP
Fig. 1 presents the shop for scheduler agent, shop
floor control (SFC) agent, order agent and the
machine (or work station) agent. This figure shows
the interaction between the scheduler agent and other
agents.
First, the agents mentioned above needs a model of
the surrounding agents. Agents have to register
themselves with the SFC agent. Second, resources
like a machine (or workstation) need to notify the
shop control agent when they have spear productivity
capability. The order agent sends request for
production capacity (to the scheduler agent or SFC
agent). The function of the shop floor control agent is
to match the request of the order agent with the offers
of the resources on a certain instance of time. The
SFC agent therefore uses the schedules it receives
regularly from one or more schedules. Order agents
and resources (or workstation) are not obliged to wait
with their request and offers until the operation is
executable or the resource is free. This enables the
agents to foresee future events and consider the
consequences of it. This will be used to have, e.g. an
idle machine (workstation), waiting for an important
order, even when work is available.
In addition to the global scheduler, each machine
(workstation) is equipped with a local scheduling
agent that makes decision on which job to process
next based solely on its partial view of the plant. For
executing a schedule, the machine (workstation) agent
needs to register itself with the shop floor scheduler
agent. Further on, the machine agent shall inform the
scheduler agent and SFC agent when it is available,
occupied, or unavailable in the (near) future. When it
becomes available again, it notifies this event to the
scheduler agent. The scheduler agent can explicitly
ask for the availability of the machine. The SFC
agent, considering all available information, will
allocate a machine (workstation) to a task. It will
inform both the machine agent and the order agent
requesting that task. The order agent and machine
agent will then autonomously settle the details of the
task to be executed. This includes setting up the
machine i.e. the workstation, co-ordinating their
activities in time, loading the necessary auxilliary
resources and exchanging information like NC-
programs. The machine (workstation), in principle,
has the possibility to schedule the tasks. This can be
done to account for small durations in the predicted
processing time; to react to resource breakdown; or to
optimize setups that have not been foreseen in
sufficient detail on higher level.
Scheduler
Agent
Machine
(workstation)
Agent
Order
Agent
Neighbor
Agent
Data
Shop Floor
Control Agent
Update orders; resources, agent address
Update orders, resources
Execute schedule
Register schedule, update schedule
Register new Resources,
update machine status
Register
Order
Request
Manufacturing
Request production capacity
Operation
Control

4.0 Agent Structure Modeling
In this work, the Belief - Desire – Intention (BDI)
agent model is adopted to model the system. The BDI
software model is one of the software models
developed for modeling and programming intelligent
agents [17].
In BDI terms Beliefs represent knowledge of the
world. It represents information state of the agent. In
computational terms, Beliefs represent the state of the
world, such as the value of a variable (i.e. constraint
variable in the proposed job shop scheduling problem
(JSSP) model), a mathematical or logical expression
(in this design constraint inqualities, JSSP constraint
expressions, and scheduling constraint equations), a
relational database and belief includes inference rules
used by the agents that allow forward chaining that
leads to new beliefs.
Desire (or goals) form another essential component of
the system state. Desire represents the motivational
state of the agent, objectives or goal that the agent
would like to accomplish [17]. In computational
terms, a desire may simply be the value of a variable,
a record structure, or a symbolic expression in some
logic. The important point is that a goal represents
some end state.
Intentions represent the deliberative state of the agent,
the agents chosen actions, which means the agent has
begun executing a plan. Computationally, intentions
may simple be a set of executing threads in a process
that achieve the goals (desires) of the system.
4.1. Specifying the BDI components of the
proposed agent based model.
Referring to the proposed system block diagram and
narrative of section 3.2:
 Scheduler Agent BDI structure
 Belief
The agent has the following belief;
 Scheduling Constraints (Resource Constraints,
task constraints, temporary constraints):
This constraint, are specified in this model design in
form of mathematical expressions, inequalities,
logical expressions that the computed schedule
parameter must satisfy.To this effect the scheduler
agent, uses combinatorics (i.e a search) to generate
scheduling values (start time for jobs, and machine)
that ensures that the set constraints are satisfied. It
uses constraint propagation computation to adjust
generated values.
 Data on available machines (i.e. available
resources):
The machine agent from time to time updates the
scheduler agent on the availability of machines (in
other words data on free machines).
 Request Order:
A data structure that list and stores request received
from the order agent.
 Job state space probability vector:
This is data of stochastic projection received from the
shop floor agent. The shop floor agent uses Markov
chain to arrive at this projection.
 Desire
The scheduler agent has the desire
 Makespan Minimization:
The objective (i.e desired end state ) of this agent is to
apply it’s scheduling heuristics in order to minimize
the manufacturing makespan.
 Assignment of jobs (unscheduled jobs,
preempted jobs) to machines:
The agents want to arrive at the state whereby all
unscheduled jobs, pre empted jobs, waiting jobs are
completely assigned to machines.
 Constraint Satisfaction:
The agent objective is for all mathematical constraint,
that would be presented in detail in this chapter later
are satisfied for whatever value of variable (e.g. start
time, processing time etc) are computed by the
scheduler algorithm as a possible solution to the JSSP.
 Intention
The scheduler agent carries out the following action
(intention); these actions are methods or threads in
software systems. This explains why the
representation is in form of program function
(methods).
 Run scheduling Algorithm ()
The scheduler agent runs the algorithm that schedules
(i.e. assigns) jobs to machines. This algorithm is
specified in this chapter.
 Probe Resource Availability ()
The scheduler agents continuously run the code to get
information on available resource (machines) from the

order agent and machine agent. This is necessary for it
to compute the next schedule, to update the current
schedule or discard the current schedule.
 Send schedule to shop floor Agent ()
This scheduler agent intention computes and sends
schedule to the shop floor agent. It is the shop floor
agent that executes the schedule.
 Execute Constraint Propagation ()
This intention is specified to run verification code by
evaluating the various constraints that have been
specified for the JSSP. These constraints are given as
mathematical expression in this design. By evaluating
constraint satisfaction for any possible solution for the
JSSP, the agent constructs new constraints (temporary
constraints) and updates its belief.
 Shop floor control Agent BDI structure
 Beliefs
The agent has the following beliefs
 Machine Status
It gets knowledge (i.e data) on the status of machines
(idle, breakdown etc) from the machine agent. It gets
this knowledge in form of updates.
 Manufacturing Schedule
It gets knowledge of completed schedules from the
scheduler agent. The schedule is the data on the
assignment of jobs to machines.
 Job Status
This is the states of all jobs at time t. It has knowledge
of the state of all jobs in the system at any time. The
status of the job could be: Unscheduled, scheduled,
waiting, processing, preempted (i.e stop or
interrupted), finished. It constitutes this belief as its
state space () at time t.
 Manufacturing Request
The encoded instruction from the order agent on the
details of requested manufacturing. What sequence of
operations should be carried out on a job, the
sequence of machining required to deliver the job.
 Order Request
A registry data structure that constitutes a listing of
order received.
 Desires
The agent desires:
 Global optimization (Markov chain)
The agent wants to keep the schedule optimized at
every time t. it uses the Markov chain to project a
forecast state space that enables the schedule agent to
adopt its Runscheduling Algorithm() intentions.
This is a key part of the proposed system.
 Job and Machine (Resource) Alignment
This agent wants to actualize the objective of
matching job(ij) with the right machine. Its Execute
Schedule () intentions is the action it carries out to
realize this objective.
 Keep Scheduler Agent Update on Job State
Transient
This desire is from the perspective of Markov Chain.
The agent wants to let the schedule agent to be aware
of the probability distribution of the non-absorbing
states of the systems at every scheduling loop or
scheduling window or upon request from the
scheduler agent.
 Intentions
The shop floor control agent carries out the following
actions (operations or plan execution):
 Initiate Markov Chain ()
The agent uses the job status updates from the order
agent to constitute the job state space vector at time t,
it evaluates the mathematics to obtain the Markov
transition matrix. It uses the transition matrix to
project the initial system state space to incorporate
stochasticity in the schedule computation of the
schedule agent. The outcome of this intention gives
the schedule agent the initial distribution (the highest
probability likelihood) from which the schedule is
computed.
 Execute Schedule ()
It executes the schedule from the schedule agent. The
schedule gives this agent the required instructions on
the allocation of operations to machines. The
execution of the schedule enables it to pass control
instructions to the machine agent.
 Run Update on Allocation ()
It updates the scheduler agent belief, the machine
agent belief and the order agent belief on machine (i.e
resource) allocation. It also updates the scheduler
agent on job state space at time t.

4.2 Modeling the Scheduling Constraints
The core of the algorithm is the agent BDI computing
of the schedule and Markov process. In a continuous
and iterative process, the agent based modeling is
used to compute and track the state of jobs to produce
initial state distribution which is then used to initialize
the Markov Chain to produce the optimized target
schedule. The scheduler agent uses constraints
programming technique to produce the schedule.
Most scheduling problems can easily be represented
as instances of the constraints satisfaction problem
[18]: given a set of variables, a set of possible values
(domain) for each variable, and a set of constraints
between the variables, assign a value to each variable,
so that all the constraints are satisfied. Hence the
principle observed by the Scheduler Agent is that
given a set of resources (i.e machines) with given
capacities, a set of operations or activities (to be
carried out at the machines) with given processing
times and resource, requirements, and a set of
temporal constraints between activities, the
scheduling problem consists of deciding when to
execute each activity or operations O, so that both
temporal constraints and resource constraints are
satisfied.
 Makespan Objective Function
The scheduler agent’s desire (goals) is to:
Minimize the manufacturing completion time, or makespan (MS) for processing all jobs. Mathematically, the
problem of minimizing the manufacturing makespan is equivalent to the following formulation (adopted from
mixed integer programming) [17]
Min Ms = f (P
ijk
), Min Tmax
Subject to (i.e. the constraints):
Bij +  Pijk Xijk ≤ Bi, j +1 ¡=1,2,....N; j = 1, 2, …j(i) -1 …..... (4.1)
K є Mij
Constraint set (4.1) ensures that an operation or activity j + 1 cannot start before the previous
operation j of the same job ¡ has been completed.
Bi,J(i) +  Pi,J(i)k – MS ≤ 0, ¡ = 1, 2, …….., N ……................(4.2)
K є Mi,J(i)
constraint set (4.2) ensures that the starting time and processing time of the last operation J(i) for
job ¡, ¡ = 1, 2, ……., N is less than or equal to the makespan (MS).
 Xijk = 1, ¡ = 1, 2,……, N; j = 1, 2, ….. J(i) ….......... (4.3)
K є Mij
Equation (4-3) ensure that one operation j of job ¡ can only be performed on only one machine k at
a time. In essence, this constraint guarantees that each job ¡ takes only one path through the
system.
Xghk + Xijk -1 ≤ Yijghk + Yghijk, …………………………. (4.4)

¡ = 1, 2, ……….., N; g = 1, 2, …….,N: ¡‡g; j = 1,2, ……, J(i);
h = 1, 2,………..,J(g); k є Mij Ո Mgh.
During scheduling decision or search, the Agent uses constraint set (4.4) to restrict two operations of
two different jobs that are scheduled on the same machine from being performed at the same time.
Thus, only one operation of one job is always performed before the other operation of the second
job.
Yijghk
+ Yghijk
≤ 1,
¡ = 1, 2, ……., N ; g = 1, 2, …….. , ¡‡g; j = 1, 2, ……J(i) …….....(4.5)
h = 1, 2, …….., J(g); k є Mij Ո Mgh.
(Bij + Pijk Xijk) – (Bgh + Pghk Xghk) + Y (1-Yghijk)≥ Pijk Xijk
¡ = 1, 2, …….N, g = 1, 2, …….. N, ¡‡g; ......................... (4.6)
j = 1, 2, ……….., J(g), h = 1, 2,……….J(g); k є Mij Ո Mgh
(Bgh + Pghk Xghk) – (Bij + Pijk Xijk) +Y(1-Yijghk)≥Pghk Xghk …….(4.7)
¡ = 1, 2,………N; g = 1, 2, …….,N; ¡ ‡ g; j = 1, 2, …….J(i);
h = 1, 2, …….., J(g); k є Mij Ո Mgh
The agents of constraint set (4.5) in its belief guarantees that if operation j and h from jobs i and g,
respectively, are to be performed on the same machine k, then the two operations cannot be
performed simultaneously. Agent implements constraint set (4.6) to ensure that if operation j of job
i is chosen to be processed before operation h of job g, the starting time and processing time of
operation j of job i must be less than the starting time of operation h of job g. The same logic
applies to constraint set (4.7) for the reverse case when operation h of job g is chosen to be
processed before operation j of job i. Agent, these constraints reinforce that one job is always
processed before a second job on a given machine to avoid contacts.
Bi1 ≥ Ri, ¡ = 1, 2, …………N ………………....................... (4.8)
Constraint set (4.8) ensures that the first operation of a job i cannot start before it is ready.
Bij ≥ 0 ¡ = 1, 2,………… N; j = 2, ………. J(i) ……….......... (4.9)
MS ≥ 0 ……………….. (4.10)
Using the non-negativity constraints (4.9) and (4.10) the agent ensures that all starting times for
the remaining operations and the manufacturing makespan are positive.

Xijk є {0, 1}, ¡ = 1, 2, ………, N; j = 1, 2, ……..J(i); ……(4.11)
k = 1, 2, …………,m
Yijghk є {0, 1}, ¡ = 1, 2, ………….N, j = 1, 2……………J(i);
g = 1, 2, ……………..N; h = 1, 2, ……,J(g)
k = 1, 2, ……………..,m
Constraints (4.11) and (4.12) show the integer constraints for the 0-1 variables.
Bi, j(i) + X
є , ( )
i, J(i)k = Ci, ¡ = 1, 2, . . … N … . . (4.13)
C¡ - 0¡ - Tmax ≤ 0 ¡ = 1, 2, ……….,N …………………… (4.14)
Tmax ≥ 0 ……………………….........................(4.15)
Constraint set (4.13) ensures that the starting time and processing time of the last operation J(i) for
job ¡, ¡ = 1, 2, …….N is equivalent to the manufacturing completion time, while constraint set (4.14)
ensures that the tardiness of job ¡, ¡ = 1, 2, ……………….N is less than or equivalent to the maximum
tardiness. With constraint (4.15) the scheduler agent ensures the maximum tardiness value will be
non negative.
Iik + ∑ Xijk + 1Pijk + Bij + 1, k = Ij, k + 1 + ∑ X ijk Pijk + 1 + Bj, k + 1 ………………. (4.16)
Constraint (4.16) established the relationships required to keep the consistency between machine’s idle time
and machine blocking times.
The scheduler agent makes scheduling decisions. This decision involves searches for time values (i.e start time
of operations i on machine Mk) that satisfy all constraints as presented.
5.1 Conclusion
When making scheduling decision, the scheduler
agent continuously carry out constraint propagation in
order to determine conditions (resulting in temporary
constraints) that a schedule must satisfy (as it relates
to operation ordering) to meet all the considered
constraints. This results in the scheduler activating the
intentions that updates the time-bounds of each of the
two operations. The algorithm specified in this work
for the scheduler agent is based on the earliest time
heuristics [19]. To enable the incorporation into the
shop floor agents inference (i.e intention) the
stochastic effect of events at the shop floor, there has
to be a way to make stochastic projections from which
the scheduler agents intention (Run scheduling
Algorithm()) can optimize the schedule computation
(which is more of a combinatorics). For the scheduler
and shop floor agents’ deliberations (intentions) to
factor in stochasticity, Markov Chain is integrated
into the solution of the JSSP in the proposed model.
The methodical leverage of the contributions of this
work would help remove the bottleneck currently
inherent at the shop floor towards the effective
exploitation of these production management
strategies.
REFERENCES
1. Albert Jones, Luis C. Rabelo “Survey of job shop
scheduling techniques” MIT, USA (2009), pp 232
2. Eric scherer “shop floor control – An integrative
framework from static scheduling models towards
an agile operations management” , CH8092
Zurich Switzerland 2002, pp. 1,2.
3. Philippe Baptiste, claude le pepe and Wim
Nuijten. Constraint-Based optimization and

Approximation for job-shop scheduling” ILOG
S.A., France (1995).
4. Baker, K.R [1974]. “Introduction to sequencing
and scheduling, Wiley & sons.
5. Akeela M.Al-Atroshi, Sama T. Azez, Baydaa S.
Bhnam An Effective Genetic Algorithm for job
shop scheduling with fuzzy Degree of
satisfaction,” University of Dohuk, Irag (2013),
pp. 180
6. Z. Othman, K. Subari, and N. Morad, “job shop
scheduling with Alternative machines using
Genetic Algorithm,” journal Tek nolosi, 41 (0).
2007.pp. 67-78
7. K. Raya, R. Saravaran, and V. Selladurai,” Mult-
Objective Optimization of parallel machine
scheduling (PMS) using Genetic Algorithm and
fuzzy Logic Approach” IE(I). journal-PR,vol. 87,
2008, pp. 26-31
8. Blazewic, S. Ecker, K. H., Pesch. E., Schmodt, G.
Ind J. Weglerz, Scheduling Computer and
Manufacturing processes, Berlin (springer) 2001,
ISBN 3-540-41931-4. PP. 322, 323.
9. Sven Banisch, Ricardo Lima and Tanya Araii Jo
“Aggregation and Emergence In Agent-Based
models: A markov chain approach” ISEG, Lisbon
(2012). ISSN 0874-4548.
10. Izquiredo, L.R., Izquiedo, S.S., Galan, J.M., and
Santos, J.I.(2009). “Techniques to understand
computer simulations: Markov chain analysis”.
Journal of Artificial societies and social
simulation, 12(1):6.
11. C. Low, C.M. Hsu and K.I. Huang, “ Lot sputting
in job shop scheduling using integer
programming”. International Journal of advanced
manufacturing technology, vol. 24, pp773-780,
2004.
12. U. Buscher and L Shen. “An integrated tabu
search algorithm for the lot streaming problem in
job shops” European journal of operational
research, vol. 19 pp 385-399, 2009.
13. Davis, W. and A. Jones (2001), ” A real-time
production scheduler for a stochastic
manufacturing environment”. 1(2): 101-112.
14. Benders, J. “Partitioning procedures for solving
mixed-variables mathematical programming
problems” Number sche mathematik, 4(3): 238-
252.
15. Dantzig, G. and P. walfe “Decomposition
principles for linear programs”, 8(1): 101-111
16. Bauer, A, Bowden, R., Brown, I. Duggen J en
Lyons, G., “shop floor control systems, design and
implementation, “chapman & Hall, London, 1991.
17. Ten Noranis Mohd Aris “Object-oriented
programming semantics representation utilizing
agents” journal of theoretical and applied
information technology sep. 2011.vol. 3, No. 1 Pp.
10, 11, 12.
18. Nuijten, W. P. M & Aarts, E. H. L. (1994)
“Constraint satisfaction for multiple capacity job-
shop scheduling” proc. 11th
European, Conference
or Artificial Intelligence, pp 635-639. John Wiley
and Sons.
19. Grimm, V.,U. Berger, F. Bastiansen, S. Eliassen,
V. Ginot, J. Giske, J. Goss-Custard, T. Grand,
S.K.Hein Z,G.Huse, A Huth, J.U.Depson, C.
Jorgansen, W.M.Mooij.B. Muller, G. Pe’er, C
piou, S.F. Railsback, A.M.Robbings, M.M
Robbins, E.Rossmanth, N. Ruger, E. Strad, S.
Souissi, R.A. Stillman. R. Vabo, U. Visser, and
D.L. De Angelis. (2006). “A standard protocol for
describing individual-based and Agent-Based
models” Ecological modeling 198(1-2): 115-126.

Agent-Based Modeling: Methods and Techniques for Scheduling Industrial Machine Operation

More Related Content

What's hot(19)

Similar to Agent-Based Modeling: Methods and Techniques for Scheduling Industrial Machine Operation(20)

More from ijtsrd(20)

Recently uploaded(20)

Agent-Based Modeling: Methods and Techniques for Scheduling Industrial Machine Operation