The document summarizes a graduate seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS). It introduces different types of FMS and components. It then discusses various deadlock avoidance policies including static, dynamic, selective static and selective dynamic approaches. These policies are evaluated based on properties like correctness, scalability, configurability and efficiency. The presentation also provides an example to illustrate the application of static and dynamic deadlock avoidance policies.
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different types of deadlocks that can occur in FMS and necessary conditions for deadlocks.
3. Methods for handling deadlocks include detection/recovery, prevention through system design, and avoidance through control policies that examine resource allocation requests.
4. The presentation focuses on the capacity-designated graph approach for deadlock avoidance, which models an FMS as a graph and develops policies to avoid deadlocks based on graph analysis.
The document provides an overview of genetic algorithms, which are algorithms inspired by biological evolution that can be used to find optimal solutions to problems. The key points covered are that genetic algorithms use mechanisms like mutation, crossover, and selection to evolve solutions over multiple generations and are well-suited for large, complex search spaces. They have been successfully applied to problems in many domains like control, design, scheduling, and more.
The document promotes a website for 3D design owned by Dr. Jacob Rubinovitz at realeyez3d.com. The site focuses on 3D design and is worth visiting to see what it offers in that area.
The document discusses the author's travels and experiences over the past 10 years, including driving to a conference in Virginia, spending time in New York City, seeing his son graduate from INSEAD in France and the Tour de France, publishing old slides online which are mostly in Hebrew, and reflecting on how much technology and his granddaughter have changed in 10 years.
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different types of deadlocks that can occur in FMS and necessary conditions for deadlocks.
3. Methods for handling deadlocks include detection/recovery, prevention through system design, and avoidance through control policies that examine resource allocation requests.
4. The presentation focuses on the capacity-designated graph approach for deadlock avoidance, which models an FMS as a graph and develops policies to avoid deadlocks based on graph analysis.
The document provides an overview of genetic algorithms, which are algorithms inspired by biological evolution that can be used to find optimal solutions to problems. The key points covered are that genetic algorithms use mechanisms like mutation, crossover, and selection to evolve solutions over multiple generations and are well-suited for large, complex search spaces. They have been successfully applied to problems in many domains like control, design, scheduling, and more.
The document promotes a website for 3D design owned by Dr. Jacob Rubinovitz at realeyez3d.com. The site focuses on 3D design and is worth visiting to see what it offers in that area.
The document discusses the author's travels and experiences over the past 10 years, including driving to a conference in Virginia, spending time in New York City, seeing his son graduate from INSEAD in France and the Tour de France, publishing old slides online which are mostly in Hebrew, and reflecting on how much technology and his granddaughter have changed in 10 years.
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different types of deadlocks that can occur in FMS and necessary conditions for deadlocks.
3. Methods for handling deadlocks include detection/recovery, prevention through system design, and avoidance through real-time control policies that examine resource allocation requests.
4. The presentation focuses on the capacity-designated graph approach for deadlock avoidance, which models an FMS as a graph to identify cycles and apply allocation policies.
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different deadlock avoidance policies including prevention, detection/recovery, and avoidance by examining resource allocation requests.
3. The capacity-designated graph (CDG) method is presented for modeling an FMS and identifying potential deadlocks based on analyzing loops in the graph. Avoidance policies aim to restrict resource allocation to avoid deadlocks.
1) The document proposes a cardinality-constrained k-means clustering approach to address practical challenges with standard k-means, such as skewed clustering and sensitivity to outliers.
2) It formulates the problem as a mixed integer nonlinear program (MINLP) and provides a convex relaxation to the problem using semidefinite programming (SDP).
3) The approach provides optimality guarantees and a rounding algorithm to recover an integer feasible solution. Numerical experiments demonstrate competitive performance versus heuristics.
Dynamic shear stress evaluation on micro turning tool using photoelasticitySoumen Mandal
The document presents an experimental method for evaluating shear stresses on a micro-turning tool using photoelasticity. A micro-turning tool was coated with a birefringent material and subjected to micro-turning of brass while capturing high-speed images. A custom-designed grey field poledioscope was used to obtain images under four analyzer orientations, which were processed to generate shear stress maps of the tool dynamically. The method allows monitoring of tool stresses during operation to prevent breakage and ensure desired performance.
SINGLE‐PHASE TO THREE‐PHASE DRIVE SYSTEM USING TWO PARALLEL SINGLE‐PHASE RECT...ijiert bestjournal
Now a days digital image processing is rapid emerging field with fast growing
applications in sciences and engineering technologies. Digital image processing has broad
spectrum of applications such as remote sensing, medical processing, radar, sonar,
robotics, sport field and automated processes [1-2]. Edge detection techniques are
employed for the detecting the edges of the primitive picture. Earlier some primitive
methods were used for the image processing. H. C. Andrew et.al. gave the method of
digital image restoration [3-5], A. K. Jain and et.al put forwarded the partial difference
equations and finite differences in image processing [6]. Image process, image models and
estimation regarding the edge detection has been flourished during last decade [7-9]. Most
modules in practical vision system depend, directly or indirectly, on the performance of an
edge detector and digital image processing.
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The document promotes a website for 3D design owned by Dr. Jacob Rubinovitz at realeyez3d.com. It suggests the site is heavily invested in 3D design and encourages visiting the site as it would be worth the time.
The document discusses a website for 3D design owned by Dr. Jacob Rubinovitz located at realeyez3d.com. The site focuses on 3D design and is worth visiting to see its extensive content in that area.
The document discusses different deadlock avoidance policies for flexible manufacturing systems. It presents four main deadlock avoidance policies: static, dynamic, selective static, and selective dynamic. The static policy creates a capacity-designated graph offline and determines feasible part movements online based on the graph. The dynamic policy creates the graph online based on current system state. The selective policies select part types to move from an input buffer using additional criteria. Examples are given comparing the policies.
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The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different types of deadlocks that can occur in FMS and necessary conditions for deadlocks.
3. Methods for handling deadlocks include detection/recovery, prevention through system design, and avoidance through real-time control policies that examine resource allocation requests.
4. The presentation focuses on the capacity-designated graph approach for deadlock avoidance, which models an FMS as a graph to identify cycles and apply allocation policies.
1. The document summarizes a seminar presentation on deadlock avoidance methods in flexible manufacturing systems (FMS).
2. It discusses different deadlock avoidance policies including prevention, detection/recovery, and avoidance by examining resource allocation requests.
3. The capacity-designated graph (CDG) method is presented for modeling an FMS and identifying potential deadlocks based on analyzing loops in the graph. Avoidance policies aim to restrict resource allocation to avoid deadlocks.
1) The document proposes a cardinality-constrained k-means clustering approach to address practical challenges with standard k-means, such as skewed clustering and sensitivity to outliers.
2) It formulates the problem as a mixed integer nonlinear program (MINLP) and provides a convex relaxation to the problem using semidefinite programming (SDP).
3) The approach provides optimality guarantees and a rounding algorithm to recover an integer feasible solution. Numerical experiments demonstrate competitive performance versus heuristics.
Dynamic shear stress evaluation on micro turning tool using photoelasticitySoumen Mandal
The document presents an experimental method for evaluating shear stresses on a micro-turning tool using photoelasticity. A micro-turning tool was coated with a birefringent material and subjected to micro-turning of brass while capturing high-speed images. A custom-designed grey field poledioscope was used to obtain images under four analyzer orientations, which were processed to generate shear stress maps of the tool dynamically. The method allows monitoring of tool stresses during operation to prevent breakage and ensure desired performance.
SINGLE‐PHASE TO THREE‐PHASE DRIVE SYSTEM USING TWO PARALLEL SINGLE‐PHASE RECT...ijiert bestjournal
Now a days digital image processing is rapid emerging field with fast growing
applications in sciences and engineering technologies. Digital image processing has broad
spectrum of applications such as remote sensing, medical processing, radar, sonar,
robotics, sport field and automated processes [1-2]. Edge detection techniques are
employed for the detecting the edges of the primitive picture. Earlier some primitive
methods were used for the image processing. H. C. Andrew et.al. gave the method of
digital image restoration [3-5], A. K. Jain and et.al put forwarded the partial difference
equations and finite differences in image processing [6]. Image process, image models and
estimation regarding the edge detection has been flourished during last decade [7-9]. Most
modules in practical vision system depend, directly or indirectly, on the performance of an
edge detector and digital image processing.
The document discusses parametric yield of integrated circuits (ICs). It begins with an overview of the topics that will be covered in the lecture, including parametric variance and its impact on profitability. It then defines parametric yield as the scenario when ICs do not have design specifications for structures like transistor sizes and interconnect properties, affecting circuit performance. The document discusses modeling process variability and its effect on circuit design. It provides examples of measuring and reducing critical dimension variability in the manufacturing process. Finally, it discusses the impact of process variability on circuit performance and the importance of statistical metrology.
IRJET-Retina Image Decomposition using Variational Mode DecompositionIRJET Journal
This document describes research applying the variational mode decomposition (VMD) algorithm to decompose retina images. VMD is presented as an improvement over existing empirical mode decomposition methods as it is less sensitive to noise and frequencies. The researchers apply VMD to decompose a retina image into intrinsic mode functions (IMFs) representing different frequency bands. Texture features are extracted from the IMFs and used to classify retina images as healthy or unhealthy, achieving perfect detection. Hardware implementation of the VMD algorithm on an FPGA is also discussed to improve computational speed for potential medical applications in disease diagnosis.
The document promotes a website for 3D design owned by Dr. Jacob Rubinovitz at realeyez3d.com. It suggests the site is heavily invested in 3D design and encourages visiting the site as it would be worth the time.
The document discusses a website for 3D design owned by Dr. Jacob Rubinovitz located at realeyez3d.com. The site focuses on 3D design and is worth visiting to see its extensive content in that area.
The document discusses different deadlock avoidance policies for flexible manufacturing systems. It presents four main deadlock avoidance policies: static, dynamic, selective static, and selective dynamic. The static policy creates a capacity-designated graph offline and determines feasible part movements online based on the graph. The dynamic policy creates the graph online based on current system state. The selective policies select part types to move from an input buffer using additional criteria. Examples are given comparing the policies.
This document discusses various techniques for creative copywriting including focusing on mood, using vivid verbs and descriptive language to engage readers emotionally, and telling a story to help sell an idea or product in an entertaining way.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
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Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
1. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Deadlock Avoidance Methods
in Flexible Manufacturing Systems
Jacob Rubinovitz
Technion - Israel Institute of Technology
Faculty of Industrial Engineering & Mgmt.
Dr. Jacob Rubinovitz
2. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Introduction: Flexible Manufacturing Systems
An automatic, programmable manufacturing system
Volume
Transfer
Lines
Dedicated CIM
Systems
Flexible
Systems
Automated
Cells
Job
Shops
Variety
Dr. Jacob Rubinovitz
3. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Introduction: Flexible Manufacturing Systems
Components of the System
•Programmable machines (CNC, Robots)
•Flexible tools and fixtures
• Flexible MH systems (AGV’s, Robots)
•Automated Storage and Retrieval System
•Computer control
Dr. Jacob Rubinovitz
4. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Introduction: Flexible Manufacturing Systems
Dr. Jacob Rubinovitz
5. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Introduction: Flexible Manufacturing Systems
Dr. Jacob Rubinovitz
6. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Deadlock-free operation is crucial
to the operation of an FMS
Research of Deadlock Avoidance Methods:
• Evaluation of different policies.
• Integration of avoidance policies into the control
software of Flexible Manufacturing Cells.
• A joint work with Jean-David Salama.
Dr. Jacob Rubinovitz
7. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Deadlock - background
Parts in FMS compete for a finite number of
resources (like robots, tools, pallets, fixtures, etc),
and share buffers or queues having limited
capacities.
A deadlock state occurs when each process in a
set of processes is blocked indefinitely from
access to resources held by other processes
within the set.
A good FMS control method must resolve or avoid
all the potential deadlocks during operation,
without seriously degrading the system
performance
Dr. Jacob Rubinovitz
8. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Necessary conditions for deadlocks
Mutual exclusion: resources can be allocated to
only one process at a time.
No preemption: resources held by one process
cannot be allocated to another process until they
are released by the process holding them.
Hold and wait: processes hold their resources
when waiting for the next required resources.
Circular wait: closed chain of processes, where
each process waits for a resource held by the next
process in the chain.
Dr. Jacob Rubinovitz
9. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Part Flow Deadlock
Machine M1 Machine M2 P1: M1→M2
(No Buffer ) (No Buffer ) P2: M2→M1
Part P1 Part P2 M1 M2
) טובורובוטMHD(
M2 M1
M2
P1: M1→M2
M1
P2: M2→M3
P3: M3→M1
M3 P1: M1→M2 M3
P2: M2→M3
P3: M3→M1
Dr. Jacob Rubinovitz
10. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Methods for handling Deadlocks
Detection/Recovery (Wysk et al., 1994)
Prevention – System design, such that
deadlocks are impossible
(Epzeleta et al., 1995;Minoura and Ding, 1991;
Viswanadham et al., 1990)
Avoidance – a control policy that
examines each request for resource
allocation prior to its execution
(Banaszak and Krogh,1990; Ferrarini and Maroni,1998;
Hsieh and Chang,1994; Lee and Lin, 1995; Revelotis
and Ferreira,1996; Xing et al.,1996;Yim et al.,1990)
Dr. Jacob Rubinovitz
11. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
(Capacity-Designated Graph (CDG
Mi Ni
3
IBi
A machine and its CDG node.
Yim, D.S., Kim, J.I. and Woo, H.S. (1997) Avoidance of deadlocks
in flexible manufacturing systems using a capacity-designated
directed graph. International Journal of Production Research, 35
(9), 2459-2475.
Dr. Jacob Rubinovitz
12. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
(Capacity-Designated Graph (CDG
N2
|N|=4, N1
A12=A21=A24=A43=A32=A14=A41=1 2 2
A42=A13=A31=A34=A23=0
N4
X={1,2,0,1} N3
C={2,2,1,3} 3 1
Fully detailed CDG graph G=(N,A,X,C).
Yim, D.S., Kim, J.I. and Woo, H.S. (1997) Avoidance of deadlocks
in flexible manufacturing systems using a capacity-designated
directed graph. International Journal of Production Research, 35
(9), 2459-2475.
Dr. Jacob Rubinovitz
13. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Loops in a Capacity-Designated Graph
N2
N1
Cycle S1: N1→N2→N1
N1 N2 N3
Cycle S2: N1→N2→N4→N1
Cycle S3: N2→N4→N3→N2
A4CDG G=(N,A) Cycle S : N →N →N
N N3
containing 57 cycles. 4 1 4 1
Cycle S : N1→N →N3→N2→N1
A CDG G=(N,A) containingN5 cycles. 4
5
5
N4
N
N!
Smax = [Σ i =1 (N -i) !·i
] -N
Dr. Jacob Rubinovitz
14. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Loops in a Capacity-Designated Graph
N2
N1
N3
A CDG G=(N,A)
containing 57 cycles.
N5
N4
Routing Intensity Index
N N
ΣΣA
i = 1 j =1,j = i
ij
RII = ; 0<RII<1
N (N - )
1
Dr. Jacob Rubinovitz
15. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Necessary Condition for a Deadlock
There is a loop S i
such that : ΣX(N ) = ΣC(N )
Nj ∈ Sj
j
Nj ∈ Sj
j
Macro N1 N2 S1: N1→N2→N1
Nodes S2: N2→N3→N2
S3: N1→N3→N1
MN1={N1,N2}
MN2={N2,N3}
S4: N1→N2→N3→N1 MN3={N1,N3}
N3 S5: N1→N3→N2→N1 MN4={N1,N2,N3}
A CDG G=(N,A)
with 5 cycles and 4 macro nodes.
Deadlock
Avoidance Policy: C(MNi ) < Σ C(Nj)-1
Nj ∈ Si
Dr. Jacob Rubinovitz
16. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Impending (Policy-Induced) Deadlocks
N2
MN1={N1,N2,N4,N5} N1 N3
MN2={N2,N3,N4}
1
2 constraints: 1 1
X(MN1) ≤ 3
X(MN2) ≤ 2 N5 1
N4
1
In order to avoid the impending deadlocks,
CDG graph (cycle) reduction is needed
Dr. Jacob Rubinovitz
18. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Objective- Deadlock Avoidance Policies
To propose various control solutions for part flow
regulation in FMCs, all structured around four
different deadlock avoidance policies (DAPs).
The DAPs will be evaluated by their
properties of:
correctness,
scalability,
configurability,
efficiency.
Dr. Jacob Rubinovitz
19. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
DAP properties
Correctness
Guarantees always a deadlock-free operation
Scalability
Computational complexity for the control system
is independent of the FMC complexity
Configurability
Can be applied to various FMC configurations
Efficiency
FMC operation is not restricted by policies that
degrade its performance
Dr. Jacob Rubinovitz
20. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
The Deadlock Avoidance Method
Request for movement Compute the current number of parts in
of a part to a node in a each relevant macro node assuming that
given CDG graph G the requesting part was transported
Yes Condition No
Allow the X(RMNi)≤C(RMNi) Refuse the
movement satisfied for all i ? movement
Dr. Jacob Rubinovitz
21. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Part Flow Management
Operation on part completed... The robot completed a delivery...
Is the robot idle and is there some open
space in the downstream station ? Checking if the transfer of each
waiting part is unfeasible,
No Yes feasible but refused, or feasible
and accepted
Transfer Transfer feasible:
2 or
unfeasible: DAP applied to more
Part waiting for allow or refuse the A part
Number
future transfer transfer selection
of accepted
0 transfers ? rule is
Transfer Transfer 1 used to
refused: allowed: Parts requesting pick a part
Part waiting for Part actually movement The requesting
future transfer moved by the remain at their part picked by
robot locations. the robot
Dr. Jacob Rubinovitz
22. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Four Different Deadlock Avoidance Policies
Static (SDAP) M1 M2
Dynamic (DDAP)
FIFO Loading Discipline M3
applied to parts in the Entry Buffer
Input Buffer
Selective Static (SSDAP)
Selective Dynamic (SDDAP) Step-by-step
M1 M2
Selection from all the backward search
different part types waiting M3
in the input buffer Entry Buffer
Dr. Jacob Rubinovitz
23. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Static Strategy
Off-line Movement of a waiting
On-line
Create a CDG from the static part feasible
information on machines, machine
capacities and complete part type Determine the resulting number of parts
routes in each relevant macro node X(RMN)
Compute the relevant macro nodes
RMNs and their capacities C(RMNs) Apply the deadlock
avoidance method
Dynamic Strategy
On-line Movement of a waiting part feasible
Create a CDG considering remaining machine sequences of each part
in the system, and assuming that the requesting part was
transported.
Determine the current number of parts
Compute the relevant macro
in each relevant macro node X(RMN)
nodes RMNs and their
assuming that the requesting part was
capacities C(RMNs).
transported.
Apply the deadlock
avoidance method
Dr. Jacob Rubinovitz
25. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Setup
CENTRAL STATION 2 # Processed Parts
WAREHOUSE Initial
State 0
EXIT STATION
0
0
STARVED
STATION 1 STATION 3
CENTRAL
BUFFER
IDLE STARVED
0 STARVED 0
0
0 STATION 4
STATION 5
INSPECTION
ENTRY STATION # Parts in System
0
Replication
Number
0 STARVED
Current Time 0 STARVED
08:00:00 0
Dr. Jacob Rubinovitz
26. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
System Structure
BP Static Deadlock Dynamic Deadlock External
Avoidance Module Avoidance Module Module
SBP SDAP SSDAP DDAP SDDAP
Deadlock
Cycle Reduction Algorithm
Detection
Module
Part Flow Cycle Search
Control Module Part Selection Rules Module
Algorithm
PSR1 PSR2 PSR3 PSR4
FMC Simulation Model
(Arena)
Dr. Jacob Rubinovitz
27. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Design
Four Different Deadlock Avoidance Policies
M1 M2
Static (SDAP)
Dynamic (DDAP) M3
Entry Buffer
FIFO Loading Discipline applied to parts in the Input Buffer
M1 M2
Selective Static (SSDAP) Step-by-step
backward search
M3
Selective Dynamic (SDDAP)
Entry Buffer
Selection from all the different part types waiting in the
input buffer
Dr. Jacob Rubinovitz
28. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Design – 2 cell types
part types machines, 4 : Cell A 3
part types machines, 5 : Cell B 6
Buffer Capacities
Cell A Cell B
1 C(CB)=0, C(IB)={0}, CBS=4 C(CB)=0, C(IB)={0}, CBS=5
2 C(CB)=4, C(IB)={0}, CBS=8 C(CB)=5, C(IB)={0}, CBS=10
3 C(CB)=0, C(IB)={1}, CBS=8 C(CB)=0, C(IB)={1}, CBS=10
4 C(CB)=4, C(IB)={1}, CBS=12 C(CB)=5, C(IB)={1}, CBS=15
5 C(CB)=0, C(IB)={2}, CBS=12 C(CB)=0, C(IB)={2}, CBS=15
Dr. Jacob Rubinovitz
29. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Design
(Part Selection Rules (PSR
PSR1 – priority to parts with minimum
remaining processes
PSR2 – priority to parts with
maximum remaining processes
PSR3 – priority based on part type
PSR4 – priority based on resource
(machine) type
Dr. Jacob Rubinovitz
30. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Design
RII – Routing Intensity Index
High RII Low RII
Cell A RII = 1 RII = 2/3
Cell B RII = 0.9 RII = 0.6
Dr. Jacob Rubinovitz
32. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Experimental Design – Product Mix
Unbalanced mix Balanced mix
P1=0.65 P1=P2=P3=0.333 Cell
P2=0.25 A
P3=0.10
P1=0.55 P1=P2=P3=P4=P5=P6= 0. 1666 Cell
P2=0.20 B
P3=0.10
P4=0.5
P5=0.5
P6=0.5
4 * 2 * 5 * 2 * 2 = 160
Dr. Jacob Rubinovitz
33. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : C(CB)=0, C(IB)={0}
Dr. Jacob Rubinovitz
34. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : C(CB)=M, C(IB)={0}
Dr. Jacob Rubinovitz
35. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : C(CB)=0, C(IB)={1}
Dr. Jacob Rubinovitz
36. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : SDDAP performance for different buffer sizes
Dr. Jacob Rubinovitz
37. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : SDDAP performance for different buffer sizes
Dr. Jacob Rubinovitz
38. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : SDDAP performance for different buffer sizes
. #Config Cell A Cell B
1 [87.8%,67.3%] [79.4%,69.7%]
2 [90.6%,82.3%] [92.4%,78.9%]
3 [92.4%,84.1%] [98.5%,80.9%]
4 [99.5%,92.2%] [98.7%,88.3%]
5 [96.2%,82.4%] [99.8%,81.8%]
Dr. Jacob Rubinovitz
39. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Incorporating a Central Buffer
Operation on a part completed: if the transfer
is unfeasible or refused by the DAP, the part is
moved to the central buffer CB, provided that
there is some open space in it .
The robot completed a delivery: the control
system checks first all the parts currently in the CB.
Priority is given to these parts in order to reduce
the amount of average WIP in the CB.
Dr. Jacob Rubinovitz
40. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Conclusions - Efficiency:
The static policies are inefficient and generate low
throughput rates in single capacity cells (SCCs(, even after
incorporating a central buffer. For this system configuration,
SDDAP is the most appropriate operating policy.
The DAPs have similar performance for double capacity cells
(DCCs( with no central buffer; Throughput is slightly higher
with SDDAP. The use of SDDAP is recommended for a high
routing intensity level.
High throughput rate is achieved for manufacturing cells of |
M| machines with attached input buffers of single capacity
and a |M| capacity central buffer.
The superiority in terms of throughput of a selective policy
(such as SSDAP or SDDAP( over a standard one (like
SDAP or DDAP( is, as expected, more apparent when the
part mix is balanced.
Dr. Jacob Rubinovitz
41. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Conclusions - Computational Complexity
The computational complexity becomes higher in the
following order of DAPs application: SDAP, SSDAP, DDAP,
and SDDAP.
SDDAP is computationally more intensive when applied
respectively to Single, Double and Triple Capacity Cells.
As a result, a static strategy may represent the best
alternative for operating a system including machines with
buffers of capacity two or more. Under such conditions, a
static policy is not less efficient than a dynamic one,
generates less WIP, and is computationally much less
complex.
Dr. Jacob Rubinovitz
42. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Potential Implementation: Cluster Tools
NEXUS 600
Six-port cluster tool that will
accommodate four process
modules and dual load-locks
and integrated wafer handler.
NEXUS 600
NEXUS 800
Eight-port cluster tool that
will accommodate six process
modules and dual load-locks
and integrated wafer handler.
NEXUS 800
Dr. Jacob Rubinovitz
43. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Questions?
Dr. Jacob Rubinovitz
44. Graduate Seminar - Deadlock Avoidance in FMS, June 2002
Results : Part Selection Rules
Dr. Jacob Rubinovitz