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Design and Run-Time Quality of Service Management Techniques for - - PowerPoint PPT Presentation

Design and Run-Time Quality of Service Management Techniques for Publish/ Subscribe Distributed Real-Time and E mbedded Systems http://www.dre.vanderbilt.edu/~jhoffert/dissertation.pdf Joe Hoffert jhoffert@dre.vanderbilt.edu Institute for


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Design and Run-Time Quality of Service Management Techniques for Publish/ Subscribe Distributed Real-Time and E mbedded Systems

Joe Hoffert

jhoffert@dre.vanderbilt.edu Institute for Software Integrated Systems Vanderbilt University Nashville, Tennessee

http://www.dre.vanderbilt.edu/~jhoffert/dissertation.pdf

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Context: QoS-enabled Publish/Subscribe for DRE Systems

Client-server technology may not suffice for all DRE systems => move towards publish/subscribe middleware

  • i.e., client-server & pub/sub

are complementary technologies Characteristics of Pub/Sub

  • Decouples location via anonymous

pub/sub

  • Decouples time via asynchronous,

time-independent data distribution

  • Decouples redundancy via

unbounded # of senders/receivers

  • Pub/Sub enables separation of concerns - decouples senders & receivers
  • QoS enables finer-grained control of system behavior/properties

3

Manifesto for QoS-enabled Pub/Sub The right data…to the right place…at the right time

Event & Notification Services Java Message Service WS Brokered Notification

Application

‘Global’ Data Store

Application Application Application Application

Data Distribution Service

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4

  • Net-centric & large-scale “systems of

systems”

  • e.g., satellite systems, shipboard

computing environments, emergency response systems

Example: QoS-enabled Pub/Sub DRE Systems

… …

vs. vs. vs.

  • Satisfying tradeoffs between multiple

(often conflicting) QoS demands

  • e.g., security, timeliness, reliability
  • Regulating & adapting to

(dis)continuous changes in runtime environments

  • e.g., online prognostics,

dependable upgrades, availability of critical tasks, dynamic resource management DRE systems increasingly realized by composing loosely-coupled services (e.g., pub/sub)

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5

Variability in the solution space (both design- and run-time)

  • Diversity in platforms, languages, protocols & tool environments
  • Enormous accidental & inherent complexities
  • Continuous evolution & change
  • Management of diverse QoS requirements

Challenges in Realizing DRE Pub/Sub Systems

Focus on QoS Management

Data reliability Provisioning of data resources Data for late arriving readers Data with time deadlines Ordered data Data priority Inter-arrival data spacing Determining liveness Data redundancy

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8

Overview of QoS Management Focus Areas

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

My PhD dissertation addresses 4 aspects of QoS management complexity.

2. Designed new composite metrics & a flexible middleware framework to evaluate & benchmark QoS mechanisms. 3. Designed machine learning-based adaptation logic to provide accurate configurations & predictable response times in flexible envs. 4. Designed monitoring mechanisms & improved machine learning- based logic to improve adaptation accuracy in dynamic envs. 1. Developed model-based techniques to reduce manual effort & ameliorate accidental complexities in deploying pub/sub DRE systems.

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9

QoS Management Focus Areas Overview (cont.)

  • 1. QoS Configuration

Development Support: QoS configurations can have numerous entities & QoS policies; how can we help DRE developers manage the complexity of developing configurations?

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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10

QoS Management Focus Areas Overview (cont.)

MuxModule MulticastModule SequencerModule

ANT Framework

FLEXMAT Testbed

  • 2. Evaluation of QoS

mechanisms: Several QoS mechanisms are available; how can we help developers evaluate QoS mechanisms for pub/sub middleware?

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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11

QoS Management Focus Areas Overview (cont.)

TCP/IP UDP/IP Multicast Custom protocol

  • 3. QoS Configuration for cloud

computing environments: Cloud computing resources which affect QoS aren’t known until runtime; how can we configure the middleware based on resources provided?

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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12

QoS Management Focus Areas Overview (cont.)

  • 4. QoS adaptation in dynamic

environments: As environments or operating conditions change, QoS can diminish; how can we adapt the middleware to support predictable QoS? System Execution Timeline

QoS Mechanism 1 (adequate)

QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment) (environment modification)

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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13

QoS Management Focus Areas Overview (cont.)

Presented solutions to these in qualifying exam; briefly review here

App

‘Global’ Data Store

App App App App Protocol 1 Protocol 2 Operating environment

QoS? QoS? QoS? QoS? QoS?

(design)

System Lifecycle Timeline

System Deployment

QoS Configuration Validation Manual QoS Configuration Techniques

Focus Area 2 Focus Area 1

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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DQML addresses the QoS configuration management challenges of (1) Correctly specified QoS properties, DQML addresses the QoS configuration management challenges of (1) Correctly specified QoS properties, (2) Correctly managed related & interacting QoS, and DQML addresses the QoS configuration management challenges of (1) Correctly specified QoS properties, (2) Correctly managed related & interacting QoS, and (3) Implementation artifacts that accurately represent design

Application- specific interpreter

Distributed QoS Modeling Language (DQML)

Focus Area 2 Focus Area 3 Focus Area 1 Focus Area 4

X

15ms 10ms

  • Associations
  • Parameter types
  • Parameter values
  • QoS policy

parameters 15

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DQML Related Publications & Presentations

Book Chapter

  • 1. Hoffert, J., Schmidt, D., & Gokhale, A. (2011).

Productivity Analysis for the Distributed QoS Modeling Language. Model-Driven Domain Analysis & Software Development: Architectures & Functions. Ed. Dr. Janis Osis & Dr. Erika Asnina, Riga Technical University, Latvia. Conference Publications

  • 2. Hoffert, J., Schmidt, D., & Gokhale, A. (2007,

June). A QoS Policy Configuration Modeling Language for Publish/Subscribe Middleware

  • Platforms. Proceedings of the Inaugural

International Conference on Distributed Event- Based Systems (DEBS), Toronto, Canada.

  • 3. Hoffert, J., Schmidt, D., & Gokhale, A. (2008,

November). DQML: A Modeling Language for Configuring Distributed Publish/Subscribe Quality of Service Policies. Proceedings of the 10th International Symposium on Distributed Objects, Middleware, & Applications (DOA), Monterrey, Mexico. Poster Publications

  • 4. Hoffert, J., Dabholkar, A., Gokhale, A., &

Schmidt, D. (2007, March). Enhancing Security in Ultra-Large Scale (ULS) Systems using Domain-specific Modeling. Spring 2007 Conference for Team for Research in Ubiquitous Secure Technology (TRUST), Berkeley, CA.

  • 5. Hoffert, J., Schmidt, D., Balakrishnan, M.,

& Birman, K. (2008, April). Trustworthy Conferencing via Domain-specific Modeling & Low Latency Reliable

  • Protocols. Spring 2008 Conference for

Team for Research in Ubiquitous Secure Technology (TRUST), Berkeley, CA.

  • 6. Hoffert, J., Gokhale, A. & Schmidt, D.

(2007, September). QoS Management in Publish/Subscribe Systems using Domain- specific Modeling. ACM/IEEE 10th International Conference on Model Driven Engineering Languages & Systems (MoDELS), Nashville, TN.

First Author

16

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FLEXMAT addresses the challenges of (1) Supporting multiple “antagonistic” QoS via new, custom protocols & (2) Understanding how environments affect multiple QoS concerns

FLEXible Middleware & Transports (FLEXMAT)

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Focus Area 1 Focus Area 3 Focus Area 2 Focus Area 4

Evaluate transport protocols with multiple operating environments using FLEXMAT testbed:

  • OpenSplice, OpenDDS
  • Various # of senders, % loss,

sending rate

  • Standard & custom protocols

MuxModule MulticastModule SequencerModule

ANT Framework

FLEXMAT Testbed

  • Leverage FLEXMAT testbed

integrated with DDS implementations

  • Leverage composite QoS metrics
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FLEXMAT Related Publications & Presentations

Conference Publications 1. Hoffert, J., Schmidt, D., & Gokhale, A. (2009, November). Evaluating Transport Protocols for Real-time Event Stream Processing Middleware & Applications. Proceedings of the 11th International Symposium on Distributed Objects, Middleware, & Applications (DOA'09), Algarve, Portugal. Workshop Publications 2. Hoffert, J., & Schmidt, D. (2008, July). Supporting Scalability & Adaptability via Adaptive Middleware & Network Transports. Proceedings of the OMG’s Workshop on Distributed Object Computing for Real-time & Embedded Systems, Washington, D.C., USA. 3. Hoffert, J., Schmidt, D., Balakrishnan, M., & Birman, K. (2008, September). Supporting Large- scale Continuous Stream Datacenters via Pub/Sub Middleware & Adaptive Transport Protocols. Proceedings of the 2nd Workshop on Large-Scale Distributed Systems & Middleware, Yorktown, NY. 4. Balakrishnan, M., Hoffert, J., Birman, K., & Schmidt, D., (2008, September). Rethinking Reliable Transport for the Datacenter. Proceedings of the 2nd Workshop on Large-Scale Distributed Systems & Middleware, Yorktown, NY. 5. Hoffert, J., & Schmidt, D. (2009, July). FLEXible Middleware & Transports (FLEXMAT) for Real- time Event Stream Processing (RT-ESP) Applications. Proceedings of the OMG’s Workshop on Distributed Object Computing for Real-time & Embedded Systems, Washington, D.C., USA.

First Author Second Author

19

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QoS Management Focus Areas Overview (cont.)

This was the focus area in my qualifying exam that I proposed to complete my dissertation.

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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21

QoS Management Focus Areas Overview (cont.)

This is a new focus area that I included while completing my dissertation.

System Execution Timeline

QoS Mechanism 1 (adequate) QoS Mechanism 1 (inadequate) QoS Mechanism 2 (adequate)

(initial environment)

(environment modification)

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Focus Area 3: Configuring DRE Systems in Flexible Envs.

Focus Area 1 Focus Area 2

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Focus Area 3 Focus Area 4

  • Resources provided as service

–Resources on demand –“Pay-as-you-go” usage fee –Computing resources

  • CPUs, RAM

–Networking resources

  • Bandwidth, network latency
  • Popular implementations

–Amazon Elastic Compute Cloud (EC2), Google App Engine, GoGrid, AppNexus, Emulab –OS, Database, RAM, CPU, Disk space, cores, load balancing, applications (e.g., Apache, Facebook servers), bandwidth

Cloud Computing for DRE systems?

Not straightforward to use Cloud in DRE systems

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Motivating Example: Search & Rescue Missions (1/2)

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DRE Cloud Scenario ‒Regional disasters (e.g., hurricane, flooding) ‒Survivors trapped ‒Search & rescue mission initiated ‒Search application fuses multiple sensor streams

  • Thermal scans from

unmanned aerial vehicles (UAVs)

  • Video from existing camera

infrastructure

  • Data streams sent to ad-hoc

datacenter for fusion & dissemination

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Motivating Example: Search & Rescue Missions (2/2)

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Datacenter Requirements ‒Operate in flexible environments, e.g.,

  • Support multiple missions &

applications

  • Varying # of senders, receivers

‒Support Multiple QoS

  • Reliability & latency
  • e.g., video & streamed thermal scans
  • Multimedia data

Ad-hoc datacenter Cloud computing infrastructure UAV providing infrared scan stream Infrastructure camera providing video stream Rescue helicopter Disaster victims

  • Local resources unavailable –

adapt to leverage available resources

  • Cloud resources, e.g., network

bandwidth, CPU speed, RAM

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Challenges for Datacenter in Cloud Environments (1/3)

Challenge 1: Reduction of Development Complexity Developing adaptive behavior is challenging:

  • Inherent complexity – designing appropriate responses for environment
  • Accidental complexity – transforming & managing appropriate responses

from design to implementation

data sending rate

X

network loss

Increased development complexity reduces availability, assurance, and portability

850 MHz CPUs, 2 GB RAM 100 Mb/s LAN

27

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Challenges for Datacenter in Cloud Environments (2/3)

Challenge 2: Accurate Configuration in Cloud Environments Environment resources unknown a priori make static configuration inadequate

Inaccurate configuration can result in loss of life & property

Ad-hoc datacenter

Cloud computing infrastructure TCP/IP

QoS mechanisms

UDP/IP Multicast

? ? ?Custom

protocol

?

28

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Challenges for Datacenter in Cloud Environments (3/3)

Challenge 3: Timely Configuration in Cloud Environments DRE systems require timely configuration

Untimely configuration can result in loss of life & property

Ad-hoc datacenter

Cloud computing infrastructure TCP/IP

QoS mechanisms

UDP/IP Multicast Custom protocol

29

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Related Research

  • Y. Eustache & J.-P. Diguet. “Reconfiguration Management in the Context of RTOS-Based

HW/SW Embedded Systems”, EURASIP Journal on Embedded Systems, pages 1 – 10. Hindawi Publishing Corp., 2008.

  • A. Zoitl et al. "A real-time reconfiguration infrastructure for distributed embedded control

systems," Proceedings of the 2010 IEEE Conference on Emerging Technologies and Factory Automation (ETFA), September 2010, Bilboa, Spain. P.-C. David & T. Ledoux. “An Aspect-Oriented Approach for Developing Self-Adaptive Fractal Components”, Software Composition, pages 82–97. Springer LNCS, 2006.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France.

  • G. Valetto et al. “Towards Service Awareness and Autonomic Features in a SIP-Enabled

Network”, Autonomic Communication, pp. 202–213. Springer-Verlag, 2006.

  • J. Imtiaz et al. “A Novel Method for Auto Configuration of Realtime Ethernet Networks”,

Proceedings of the IEEE International Conference on Emerging Technologies and Factory Automation, September 2008, Hamburg, Germany. Xiangping Bu et al. "A Reinforcement Learning Approach to Online Web Systems Auto- configuration“, 29th IEEE International Conference on Distributed Computing Systems, June 2009, Montreal, Canada.

Good for configuring local components

QoS in Cloud Environments: Related Research

30

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Related Research

  • Y. Eustache & J.-P. Diguet. “Reconfiguration Management in the Context of RTOS-Based

HW/SW Embedded Systems”, EURASIP Journal on Embedded Systems, pages 1 – 10. Hindawi Publishing Corp., 2008.

  • A. Zoitl et al. "A real-time reconfiguration infrastructure for distributed embedded control

systems," Proceedings of the 2010 IEEE Conference on Emerging Technologies and Factory Automation (ETFA), September 2010, Bilboa, Spain. P.-C. David & T. Ledoux. “An Aspect-Oriented Approach for Developing Self-Adaptive Fractal Components”, Software Composition, pages 82–97. Springer LNCS, 2006.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France.

  • G. Valetto et al. “Towards Service Awareness and Autonomic Features in a SIP-Enabled

Network”, Autonomic Communication, pp. 202–213. Springer-Verlag, 2006.

  • J. Imtiaz et al. “A Novel Method for Auto Configuration of Realtime Ethernet Networks”,

Proceedings of the IEEE International Conference on Emerging Technologies and Factory Automation, September 2008, Hamburg, Germany. Xiangping Bu et al. "A Reinforcement Learning Approach to Online Web Systems Auto- configuration“, 29th IEEE International Conference on Distributed Computing Systems, June 2009, Montreal, Canada.

QoS in Cloud Environments: Related Research

31

Good for developing autoconfiguration applications

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SLIDE 25

Related Research

  • Y. Eustache & J.-P. Diguet. “Reconfiguration Management in the Context of RTOS-Based

HW/SW Embedded Systems”, EURASIP Journal on Embedded Systems, pages 1 – 10. Hindawi Publishing Corp., 2008.

  • A. Zoitl et al. "A real-time reconfiguration infrastructure for distributed embedded control

systems," Proceedings of the 2010 IEEE Conference on Emerging Technologies and Factory Automation (ETFA), September 2010, Bilboa, Spain. P.-C. David & T. Ledoux. “An Aspect-Oriented Approach for Developing Self-Adaptive Fractal Components”, Software Composition, pages 82–97. Springer LNCS, 2006.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France.

  • G. Valetto et al. “Towards Service Awareness and Autonomic Features in a SIP-Enabled

Network”, Autonomic Communication, pp. 202–213. Springer-Verlag, 2006.

  • J. Imtiaz et al. “A Novel Method for Auto Configuration of Realtime Ethernet Networks”,

Proceedings of the IEEE International Conference on Emerging Technologies and Factory Automation, September 2008, Hamburg, Germany. Xiangping Bu et al. "A Reinforcement Learning Approach to Online Web Systems Auto- configuration“, 29th IEEE International Conference on Distributed Computing Systems, June 2009, Montreal, Canada.

QoS in Cloud Environments: Related Research

32

Good for autoconfiguration when timeliness is not a driving concern

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Property Description Distributed Configuration Does the technique help autoconfiguration of QoS across machine boundaries? Online Configuration Does the technique perform configuration adjustments while system is running? Timely Configuration Does the technique provide bounded-time – ideally, constant-time – response? What properties help us assess research to configure QoS in cloud environments?

Properties for QoS Support in Cloud Environments

33

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QoS in Cloud Environments: Related Work

34

Distributed configuration Local configuration Online configuration Static configuration Unbounded time complexity Bounded time complexity

Does the technique autoconfigure across machines?

Bu Grace David Imtiaz Zoitl Eustache Valetto

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SLIDE 28

QoS in Cloud Environments: Related Work

35

Distributed configuration Local configuration Online configuration Static configuration Unbounded time complexity Bounded time complexity

Bu Grace David Imtiaz Zoitl Eustache Valetto

Does the technique provide

  • nline configuration?
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QoS in Cloud Environments: Related Work

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Distributed configuration Local configuration Online configuration Static configuration Unbounded time complexity Bounded time complexity

Bu Grace David Imtiaz Zoitl Eustache Valetto

Does the technique provide bounded time complexity?

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SLIDE 30

Online configuration Static configuration

Current gap makes it hard for DRE systems in cloud environments to configure QoS in a timely manner

QoS in Cloud Environments: Related Work

37

Distributed configuration Local configuration Unbounded time complexity Bounded time complexity

Bu Grace David Imtiaz Zoitl Eustache Valetto

Gap: Configure across machines in a timely manner

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Solution Approach: ADAptive M/W And Network Transports

38

Distributed configuration Local configuration Online configuration Static configuration Unbounded time complexity Bounded time complexity

Bu Grace David Imtiaz Zoitl Eustache Valetto

ADAMANT

Solution Approach: Bounded time, accurate configuration of transport protocols for QoS-enabled pub/sub middleware in ADAMANT

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Some Configuration Approaches Considered

39 Network % loss # receivers Sending rate protocol parameters

Policy-based configuration Artificial neural network Decision tree Support vector machine (SVM)

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Approach Boundedness Accuracy (known) Accuracy (unknown) Development complexity Policy based Yes Perfect (100%) Low (default) Medium -High Reinforcement Learning No High Medium Low Decision Tree Yes (data dependent) High (99%) High (87%) Low Neural Network Yes (constant) Perfect (100%) High (85%) Low SVM Yes (constant) Perfect (100%) High (79%) Low

Initial Evaluation of Configuration Approaches

40

Evaluated approaches based on:

  • Boundedness/time complexity
  • Accuracy for environments known at training time
  • Accuracy for environments unknown a priori
  • Complexity of managing environments with responses
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Approach Boundedness Accuracy (known) Accuracy (unknown) Development complexity Policy based Yes Perfect (100%) Low (default) Medium -High Reinforcement Learning No High Medium Low Decision Tree Yes (data dependent) High (99%) High (87%) Low Neural Network Yes (constant) Perfect (100%) High (85%) Low SVM Yes (constant) Perfect (100%) High (79%) Low

Initial Evaluation of Configuration Approaches

41

Evaluated approaches based on:

  • Boundedness/time complexity
  • Accuracy for environments known at training time
  • Accuracy for environments unknown a priori
  • Complexity of managing environments with responses
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SLIDE 35

Approach Boundedness Accuracy (known) Accuracy (unknown) Development complexity Policy based Yes Perfect (100%) Low (default) Medium -High Reinforcement Learning No High Medium Low Decision Tree Yes (data dependent) High (99%) High (87%) Low Neural Network Yes (constant) Perfect (100%) High (85%) Low SVM Yes (constant) Perfect (100%) High (79%) Low

Initial Evaluation of Configuration Approaches

42

Evaluated approaches based on:

  • Boundedness/time complexity
  • Accuracy for environments known at training time
  • Accuracy for environments unknown a priori
  • Complexity of managing environments with responses
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SLIDE 36

Approach Boundedness Accuracy (known) Accuracy (unknown) Development complexity Policy based Yes Perfect (100%) Low (default) Medium -High Reinforcement Learning No High Medium Low Decision Tree Yes (data dependent) High (99%) High (87%) Low Neural Network Yes (constant) Perfect (100%) High (85%) Low SVM Yes (constant) Perfect (100%) High (79%) Low

Initial Evaluation of Configuration Approaches

43

Evaluated approaches based on:

  • Boundedness/time complexity
  • Accuracy for environments known at training time
  • Accuracy for environments unknown a priori
  • Complexity of managing environments with responses
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SLIDE 37

Approach Boundedness Accuracy (known) Accuracy (unknown) Development complexity Policy based Yes Perfect (100%) Low (default) Medium -High Reinforcement Learning No High Medium Low Decision Tree Yes (data dependent) High (99%) High (87%) Low Neural Network Yes (constant) Perfect (100%) High (85%) Low SVM Yes (constant) Perfect (100%) High (79%) Low

Initial Evaluation of Configuration Approaches

44

Evaluated approaches based on:

  • Boundedness/time complexity
  • Accuracy for environments known at training time
  • Accuracy for environments unknown a priori
  • Complexity of managing environments with responses
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ADAptive Middleware & Network Transports (ADAMANT)

Adaptive Network Transports (ANT) framework

  • Transport protocol framework
  • Composable modules
  • Fine-grained protocol control

XOR encoding FEC-sender ACK-based Reed-Solomon encoding FEC-receiver NAK-based

Custom protocol 1 Custom protocol 2

XOR encoding FEC-sender ACK-based Reed-Solomon encoding FEC-receiver NAK-based FEC-group Tornado encoding

Data Distribution Service (DDS)

  • OMG pub/sub standard, rich QoS support
  • OpenDDS, OpenSplice implementations
  • Pluggable transport protocol frameworks
  • Open source

ADAMANT incorporates:

Protocol Optimization

Artificial Neural Network (ANN)

  • Trained on protocol properties
  • Interpolates/Extrapolates for new

environments

5 10 15 20 25 2 4 6

Interpolation between training data

  • Determines optimal protocol/parameters

45

  • Constant time performance
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SLIDE 39

ADAMANT

SAR Topic(s)

Adaptive Network Transport (ANT) Protocols

Data Writer Data Reader Data Reader

App Publisher App Subscriber Domain

Protocol Optimizer (ANN)

Key:

Control interaction between subsystems

  • Assoc. between reader/writer &topic

DDS

  • 1. ADAMANT queries

environment for resources.

  • 2. Resource information

passed to ADAMANT.

  • 3. ANN selects appropriate protocol

in a timely manner & notifies ANT

Cloud Computing Environment

ADAMANT

  • 4. ANT configures the

protocol for the middleware

ADAMANT Architecture & Control Flow

46

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Addressing Challenges for Datacenter in Cloud Envs. (1/3)

ADAMANT addresses challenge 1 (development complexity) via ANNs to manage protocol selection & implementation transformation ANNs manage the development complexity of protocol management:

  • Automatically manage inherent complexity of relationships between

environment and protocols

  • Used directly in implementations (i.e., avoids accidental complexity of

developing implementation)

RAM Network speed Network % loss protocol parameters ANN

Adaptive Network Transport (ANT) Framework

Autonomic Configuration Controller

ADAMANT

data sending rate

X

network loss 3 GHz CPUs, 4 GB RAM

47

1 Gb/s LAN

CPU speed Sending rate

… DDS

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SLIDE 41

48

Addressing Challenges for Datacenter in Cloud Envs. (2/3)

ADAMANT addresses challenge 2 (accurate configuration) by overfitting ANN to data Overfitting data increases ANN’s accuracy for selecting appropriate protocol

ADAMANT accurately selects correct protocol

Ad-hoc datacenter

Cloud computing infrastructure TCP/IP

QoS mechanisms

UDP/IP Multicast Custom protocol

48

X X X

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SLIDE 42

Addressing Challenges for Datacenter in Cloud Envs. (3/3)

ADAMANT addresses challenge 3 (timely configuration) via ANN w/ bounded constant-time response ANNs are equation based:

  • Equations based on nodes and connections

CPU speed, RAM Network speed Network % loss protocol parameters ANN

  • Fixed number of inputs, hidden nodes, outputs (determined at off-line

training time)

  • Constant # of connections (determined at training time)

49

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Empirical Results – Different Hardware Different Protocols

Difference in hardware triggers a difference in appropriate transport protocol Experimental environment:

  • Using protocols that balance reliability and low latency
  • IP Multicast w/ NAKs (NAKcast)
  • Modified FEC (Ricochet)
  • Varied CPU speed, network bandwidth
  • Conducted several training runs

50

1000 2000 3000 4000 5000 6000 7000 8000 9000 1 2 3 4 5 ReLate2 Values Experiment

850 MHz CPU, 100Mb LAN, 3 rcvrs, 5% loss

NAKCast 0.001 - 25Hz Ricochet R4 C3 - 25Hz 3500 3700 3900 4100 4300 4500 1 2 3 4 5 ReLate2 Values Experiment

3 GHz CPU, 1Gb LAN, 3 rcvrs, 5% loss

NAKcast 0.001 25Hz Ricochet R4C3 - 25Hz

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SLIDE 44

10 20 30 40 50 60 70 80 90 100 1 2 3 4 5 6 7 8 9 10

Accuracy for excluded data (%) Training Run

ANN Accuracy (2-fold cross-validation)

36 hidden nodes 24 hidden nodes 12 hidden nodes 6 hidden nodes

Empirical Results - Accuracy

51

82 84 86 88 90 92 94 96 98 100 102 1 2 3 4 5 6 7 8 9 10

Accuracy (%) Training Run

ANN Accuracy (known environments)

36 hidden nodes 24 hidden nodes 12 hidden nodes 6 hidden nodes

ANNs w/ 24 nodes provide most instances of 100% accuracy, highest average accuracy with 2-fold cross-validation (78%) Experimental environment:

  • 394 operating environments
  • Varied CPU speed, network bandwidth, # of data receivers, sending rate
  • Conducted several training runs
  • ANN outputs tested against known correct responses & cross-validation
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Evaluation Criteria Description (H1) Adjust for known environment Hypothesize that ADAMANT will provide adjustment improvement for known environments at least 85% of the time

Qualifying Exam Hypothesis for ADAMANT

52

Using ANNs, ADAMANT provides 100% accurate adjustment for known environments

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SLIDE 46

ANNs provide the predictable decision-making timeliness needed for DRE systems ADAMANT addresses the challenges of (1) Development complexity via machine learning to determine protocols, (2) Configuration accuracy via overfitted supervised machine learning & (3) Configuration timeliness via equation-based machine learning

Empirical Results – ANN Timeliness

53

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 9 10

Time (µs) Classification Run

Average ANN Response Times

6 hidden nodes 12 hidden nodes 24 hidden nodes 36 hidden nodes 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3 4 5 6 7 8 9 10

Time (µs) Classification Run

Std Deviation ANN Response Times

6 hidden nodes 12 hidden nodes 24 hidden nodes 36 hidden nodes

Experimental environment:

  • 394 operating environments
  • Emulab: 3 GHz CPU, 2GB of RAM, Fedora Core 6 w/ real-time patches
  • Sub 10 µs average response times for all ANN configurations
  • Sub µs jitter for all ANN configurations
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SLIDE 47

ADAMANT Related Publications & Presentations

Conference Publications 1. Hoffert, J., Schmidt, D., & Gokhale, A. (2010, November). Adapting Distributed Real-time and Embedded Publish/Subscribe Middleware for Cloud-Computing Environments, Proceedings of the ACM/IFIP/USENIX 11th International Middleware Conference (Middleware 2010), Bangalore, India. 2. Hoffert, J., & Schmidt, D. (2010, October). Evaluating Supervised Machine Learning for Adapting Enterprise DRE Systems, Proceedings of the 2010 International Symposium on Intelligence Information Processing and Trusted Computing (IPTC 2010), Huanggang, China. Workshop Publications 3. Hoffert, J., Schmidt, D., & Gokhale, A. (2010, April). Adapting and Evaluating Distributed Real- time and Embedded Systems in Dynamic Environments,The 1st International Workshop on Data Dissemination for Large scale Complex Critical Infrastructures (DD4LCCI 2010), Valencia, Spain.

First Author

54

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SLIDE 48

56

Focus Area 4: Adapting DRE Systems in Dynamic Envs.

Focus Area 1 Focus Area 2 Focus Area 4 Focus Area 3

Motivating Example: Smart City Ambient Assisted Living (SCAAL)

  • Aging population increasing, # of health care workers decreasing
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SLIDE 49

Motivating Example: SCAAL Application (cont.)

59 High-resolution health monitoring GPS Videocamera Cell phone PDA Mobility Sensory Enhancing Equipment Smart City Law enforcement Doctors Surveillance infrastructure Firefighters EMS Healthcare facilities

Scenario

  • Aging population increasing, # of health care workers decreasing
  • Increase elderly autonomy in urban areas via coordination of personal

equipment & sensing/aware “smart cities”

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SLIDE 50

Motivating Example: SCAAL Application (cont.)

Scenario

  • Aging population increasing, # of health care workers decreasing
  • Increase elderly autonomy in urban areas via coordination of personal

equipment & sensing/aware “smart cities”

  • Utilize personal data center to manage personal & environment data

60 High-resolution health monitoring GPS Videocamera Cell phone Mobility

Personal DataCenter

PDA Sensory Enhancing Equipment Smart City Law enforcement Doctors Surveillance infrastructure Firefighters EMS Healthcare facilities

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SLIDE 51

Motivating Example: SCAAL Application (cont.)

Requirements

  • Operate in dynamic environment, e.g.,
  • Varying # of senders, receivers
  • Varying network bandwidth, loss
  • Support QoS as environment changes
  • Reliability & latency
  • e.g., high resolution health

monitoring

  • Multimedia data

61

Personal DataCenter

  • Varying data sending rates (e.g.,

more updates for critical data)

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SLIDE 52

62

Challenges for QoS in Dynamic Environments (1/2)

Challenge 1: Environment monitoring & update dissemination

(initial environment)

Elderly person traveling through smart city

(environment modification)

… Low sending rate High sending rate, More detailed information Normal health information, Low update rate required

As environment changes, updates need to be propagated throughout the application.

Doctor detects health anomaly, update rate increased

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SLIDE 53

63

Challenges for QoS in Dynamic Environments (2/2)

Challenge 2: Optimal accuracy for unknown environments while maintaining timeliness

QoS Mechanism 1 (inadequate) Transport protocol 1 (inadequate) High sending rate, more detailed health information

  • Timeliness concerns need to be

addressed while selecting an adequate QoS mechanism

Transport protocol 1 (adequate)

  • Ideally want accuracy for

unknown environments to rival accuracy for known environments

  • Inaccurate adjustment could

lead to reduced health or death

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SLIDE 54

Related Research

PrismTech’s Tuner application, http://www.opensplice.com Real-Time Innovations’ RTI Analyzer, RTI Scope, & RTI Protocol Analyzer, http://rti.com/products/developer_platform

  • M. Caporuscio et al. “Design and Evaluation of a Support Service for Mobile, Wireless

Publish/Subscribe Applications”, IEEE Transactions on Software Engineering, vol. 29, no. 12, pages1059–1071.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France

  • P. Vienne & J.-L. Sourrouille. “A Middleware for Autonomic QoS Management Based on
  • Learning. Proceedings of the 5th International Workshop on Software Engineering &

Middleware, September 2005, Lisbon, Portugal

  • C. Hersenns et al. "Context-driven Autonomic Adaptation of SLA“, 6th International

Conference on Service Oriented Computing, December 2008, Sydney, Australia

Good for manually checking the run-time QoS status

QoS in Dynamic Environments: Related Research

66

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SLIDE 55

Related Research

PrismTech’s Tuner application, http://www.opensplice.com Real-Time Innovations’ RTI Analyzer, RTI Scope, & RTI Protocol Analyzer, http://rti.com/products/developer_platform

  • M. Caporuscio et al. “Design and Evaluation of a Support Service for Mobile, Wireless

Publish/Subscribe Applications”, IEEE Transactions on Software Engineering, vol. 29, no. 12, pages1059–1071.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France

  • P. Vienne & J.-L. Sourrouille. “A Middleware for Autonomic QoS Management Based on
  • Learning. Proceedings of the 5th International Workshop on Software Engineering &

Middleware, September 2005, Lisbon, Portugal

  • C. Hersenns et al. "Context-driven Autonomic Adaptation of SLA“, 6th International

Conference on Service Oriented Computing, December 2008, Sydney, Australia

Good for developing adaptation applications

QoS in Dynamic Environments: Related Research

67

slide-56
SLIDE 56

Related Research

PrismTech’s Tuner application, http://www.opensplice.com Real-Time Innovations’ RTI Analyzer, RTI Scope, & RTI Protocol Analyzer, http://rti.com/products/developer_platform

  • M. Caporuscio et al. “Design and Evaluation of a Support Service for Mobile, Wireless

Publish/Subscribe Applications”, IEEE Transactions on Software Engineering, vol. 29, no. 12, pages1059–1071.

  • P. Grace et al. “Deep Middleware for the Divergent Grid”, Proceedings of the

ACM/IFIP/USENIX 2005 International Conference on Middleware, November 2005, Grenoble, France

  • P. Vienne & J.-L. Sourrouille. “A Middleware for Autonomic QoS Management Based on
  • Learning. Proceedings of the 5th International Workshop on Software Engineering &

Middleware, September 2005, Lisbon, Portugal

  • C. Hersenns et al. "Context-driven Autonomic Adaptation of SLA“, 6th International

Conference on Service Oriented Computing, December 2008, Sydney, Australia

Good for adaptation when timeliness is not a driving concern

QoS in Dynamic Environments: Related Research

68

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SLIDE 57

Property Description Monitor environment Does the technique know when the environment has changed? Dynamic adaptation Does the technique perform adaptation adjustments while system is running? Timely adaptation Can the technique change to a more appropriate protocol in a timely manner? What properties help us assess research to support QoS in dynamic environments?

Properties for QoS Support in Dynamic Environments

69

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SLIDE 58

QoS in Dynamic Environments: Related Work

70

Monitor environment No monitoring Timely adaptation Best-effort/no adaptation Static configuration Dynamic adaptation

PrismTech RTI

Does the technique monitor the system for changes?

Bu Grace Caporuscio Vienne Herssens

slide-59
SLIDE 59

QoS in Dynamic Environments: Related Work

71

No monitoring Static configuration

PrismTech RTI Bu Grace Caporuscio Vienne Herssens

Does the technique adapt while the system is running?

Timely adaptation Best-effort/no adaptation Dynamic adaptation Monitor environment

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SLIDE 60

QoS in Dynamic Environments: Related Work

72

No monitoring Static configuration

Does the technique provide timely transition to support QoS?

PrismTech RTI Bu Grace Caporuscio Vienne Herssens

Timely adaptation Best-effort/no adaptation Dynamic adaptation Monitor environment

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SLIDE 61

Timely adaptation Best-effort/no adaptation

QoS in Dynamic Environments: Open Issues

73

No monitoring Static configuration

PrismTech RTI Bu Grace Caporuscio Vienne Herssens

Current gap makes it hard for DRE systems in dynamic environments to adapt QoS in a timely manner Gap: Monitor, analyze, & adapt in a timely manner

73

Dynamic adaptation Monitor environment

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SLIDE 62

Solution Approach: Adaptive M/W & Network Transports++

74

No monitoring Static configuration

PrismTech RTI Bu Grace Caporuscio Vienne Herssens

74

Solution Approach: Timely autonomic transport protocol adaptation for QoS-enabled pub/sub middleware in ADAMANT++

ADAMANT++

Timely adaptation Best-effort/no adaptation Dynamic adaptation Monitor environment

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SLIDE 63

SAR Topic

Adaptive Network Transport (ANT) Protocols

Data Writer Data Writer Data Reader

Domain

  • Env. Monitor

Topic

Data Reader Data Writer Data Writer

Autonomic Adaptation Controller Protocol Optimizer

Key:

Order of interaction between subsystems

  • Assoc. between reader/writer & topic

DDS

  • 1. Middleware disseminates

environment feedback

  • 2. Controller monitors feedback ,

sends to optimizer

  • 3. Optimizer determines optimal

protocol & settings (leveraging multiple machine learning techniques), returns to controller

  • 4. Controller compares current &
  • ptimal settings, notifies ANT as

needed

  • 5. ANT dynamically updates the protocol

and/or settings to maintain QoS

1 2 3 4 N

  • Env. Monitor Publisher
  • Env. Monitor Subscriber

Video & Infrared Publisher Rescue Helicopter Subscriber

ADAMANT++ Architecture & Control Flow

75

Boldface Update from previous ADAMANT architecture for configuration

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SLIDE 64

76

Addressing Challenges for QoS in Dynamic Envs. (1/2)

ADAMANT++ addresses Challenge 1 (disseminating updates) via environment monitoring topic

ADAMANT++ leverages DDS to disseminate updates; QoS policies apply to monitoring topic

SAR Topic

Adaptive Network Transport (ANT) Protocols

Data Writer Data Writer Data Reader

Domain

  • Env. Monitor

Topic

Data Reader Data Writer Data Writer

… DDS

  • Env. Monitor Publisher
  • Env. Monitor Subscriber

Video & Infrared Publisher Rescue Helicopter Subscriber

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SLIDE 65

77

Addressing Challenges for QoS in Dynamic Envs. (2/2)

ADAMANT++ addresses Challenge 2 (increasing accuracy) via Timely Integrated Machine Learning (TIML)

TIML yields 8.6% accuracy increase for unknown environments (compared to just ANN), maintains timeliness

Environment update Perfect Hash Artificial Neural Network Support Vector Machines

Timely Integration of Machine Learning (TIML)

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SLIDE 66

Evaluation Criteria Description (H2) Adjust for unknown environment Hypothesize that ADAMANT will provide adjustment improvement for unknown environments more than 50% of the time

Proposed Experiment: ADAMANT & Dynamic Environments

78

Leveraging TIML, ADAMANT++ provides 86% accuracy for unknown environments.

TIML

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SLIDE 67

Empirical Results – TIML Timeliness

79

TIML provides the predictable adaptation timeliness needed for DRE systems Experimental environment:

  • 394 operating environments
  • Emulab: 3 GHz CPU, 2GB of RAM, Fedora Core 6 w/ real-time patches
  • 12 µs response times for determining to use ANN or SVM
  • Jitter within timestamp resolution for ANN and SVM paths (i.e., +/- 1 µs)

10 11 12 13 14 1 101 201 301 401 501 601 701 801 901

Time (µs) Classification Run

TIML Response Times

ANN path SVM path

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SLIDE 68

Empirical Results – ANT Timeliness

80

ANT provides the predictable reconfiguration timeliness needed for DRE systems Experimental environment:

  • 394 operating environments
  • Emulab: 3 GHz CPU, 2GB of RAM, Fedora Core 6 w/ real-time patches
  • Sub 10 µs response times for switching between NAKcast and Ricochet
  • No jitter for all ANT reconfigurations

1 2 3 4 5 6 1 101 201 301 401 501 601 701 801 901

Time (µs) Reconfiguration Run

ANT Reconfiguration Times

No reconfiguration Ricochet to NAKcast NAKcast to Ricochet

ADAMANT++ addresses the challenges of (1) Disseminating environment updates, (2) Maximizing accuracy while maintaining timeliness

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SLIDE 69

ADAMANT++ validates the three hypotheses from my qualifying exam: (1) > 85% accuracy for known environments (achieved 100%), (2) > 50% accuracy for unknown environments (achieved 86%), (3) Constant-time response Evaluation Criteria Description (H3) Provide bounded, constant time adaptation Hypothesize that ADAMANT will adjust to new

  • perating environment in bounded constant time

(i.e., O(1))

Proposed Experiment: ADAMANT & Dynamic Environments

81

Leveraging equation- based machine learning and ANT, ADAMANT++ responds to new

  • perating environments

in constant time.

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SLIDE 70

These decisions could be made at an application level & obeyed by ADAMANT++

ADAMANT++ Sensitivity Analysis

82

Should adaptation always occur to get better QoS? Are there times when the adjustment doesn’t warrant the adaptation? How can we analyze the value of adapting?

13% QoS Increase 24% QoS Increase 3% QoS Increase 21% QoS Increase

Using threshold of 10% increase, we would reject adaptation for only 3% increase.

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SLIDE 71

Doctoral Research Contributions

Focus Area Challenge Approach Contribution Valid QoS Design

  • Design-time

QoS Validation

  • DSML that validates QoS

configuration & generates implementation artifacts

  • DQML

Evaluation of QoS Mechanisms

  • Run-time QoS

Guidance & Flexibility

  • Pub/sub middleware with

flexible protocol framework

  • Composite metrics & empirical

analysis

  • FLEXMAT
  • ReLate2

metrics Autonomic Configuration for QoS

  • Manage QoS

in Flexible Environments

  • Autonomic protocol config. in

flexible resource envs

  • Timely adaptation based on

supervised learning

  • ADAMANT

Autonomic Adapation for QoS

  • Manage QoS

in Dynamic Environments

  • Autonomic adaptation of

protocols in dynamic envs

  • Increased accuracy via

integration of supervised learning integration

  • ADAMANT++
  • TIML

Enhancing Productivity & Flexibility for QoS-enabled Pub/Sub DRE Systems www.dre.vanderbilt.edu/~jhoffert/research

83

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SLIDE 72

Conference Publications 4. Hoffert, J., Jiang S., & Schmidt, D. (2007, April). A Taxonomy of Discovery Services & Gap Analysis for Ultra-Large Scale Systems. Proceedings of the 45th Annual Southeast Regional Conference, Winston-Salem, NC 5. Hoffert, J., Schmidt, D., & Gokhale, A. (2007, June). A QoS Policy Configuration Modeling Language for Publish/Subscribe Middleware Platforms. Proceedings of the Inaugural International Conference on Distributed Event-Based Systems, Toronto, Canada. 6. Hoffert, J., Schmidt, D., & Gokhale, A. (2008, November). DQML: A Modeling Language for Configuring Distributed Publish/Subscribe Quality of Service Policies. Proceedings of the 10th International Symposium on Distributed Objects, Middleware, & Applications, Monterrey, Mexico.

Summary of Publications & Presentations

First Author

84

Journal Publications 1. Hoffert, J., Mack, D., & Schmidt, D. (2010) Integrating Machine Learning Techniques to Adapt Protocols for QoS-enabled Distributed Real-time and Embedded Publish/Subscribe Middleware, International Journal of Network Protocols and Algorithms, Vol. 2, No. 3. 2. Hoffert, J., Schmidt, D., & Gokhale, A. (2011) Evaluating Timeliness and Accuracy Trade-offs of Supervised Machine Learning for Adapting Enterprise DRE Systems in Dynamic Environments, (In submission to) International Journal of Computational Intelligence Systems. 3. Hoffert, J., Gokhale, A., & Schmidt, D. (2011) Autonomic Adaptation of Publish/Subscribe Middleware in Dynamic Environments, (In submission to) International Journal of Adaptive, Resilient and Autonomic Systems.

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SLIDE 73

Conference Publications (cont.) 7. Hoffert, J., Schmidt, D., & Gokhale, A. (2009, November). Evaluating Transport Protocols for Real-time Event Stream Processing Middleware & Applications. The11th International Symposium on Distributed Objects, Middleware, & Applications, Algarve, Portugal. 8. Hoffert, J. & Schmidt, D. (2009, July). Maintaining QoS for Publish/Subscribe Middleware in Dynamic Environments. 3rd ACM International Conference on Distributed Event-Based Systems, Nashville, TN. 9. Hoffert, J., & Schmidt, D. (October, 2010). Evaluating Supervised Machine Learning for Adapting Enterprise DRE Systems, International Symposium on Intelligence Information Processing and Trusted Computing, Huanggang, China.

  • 10. Hoffert, J., Schmidt, D., & Gokhale, A. (November, 2010). Adapting Distributed Real-time and

Embedded Publish/Subscribe Middleware for Cloud-Computing Environments, ACM/IFIP/USENIX 11th International Middleware Conference , Bangalore, India.

Summary of Publications & Presentations (cont.)

First Author

85

Book Chapters

  • 11. Hoffert, J., Schmidt, D., & Gokhale, A. Productivity Analysis for the Distributed QoS Modeling
  • Language. Model-Driven Domain Analysis & Software Development: Architectures & Functions.
  • Ed. Dr. Janis Osis & Dr. Erika Asnina, IGI Global.
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SLIDE 74

Summary of Publications & Presentations (cont.)

First Author Second Author

Workshop Publications

  • 12. Hoffert, J., & Schmidt, D. (2008, July). Supporting Scalability & Adaptability via Adaptive

Middleware & Network Transports. Proceedings of the OMG’s Workshop on Distributed Object Computing for Real-time & Embedded Systems, Washington, D.C., USA.

  • 13. Hoffert, J., Schmidt, D., Balakrishnan, M., & Birman, K. (2008, September). Supporting Large-

scale Continuous Stream Datacenters via Pub/Sub Middleware & Adaptive Transport Protocols. Proceedings of the 2nd Workshop on Large-Scale Distributed Systems & Middleware, Yorktown, NY.

  • 14. Balakrishnan, M., Hoffert, J., Birman, K., & Schmidt, D., (2008, September). Rethinking Reliable

Transport for the Datacenter. Proceedings of the 2nd Workshop on Large-Scale Distributed Systems & Middleware, Yorktown, NY.

  • 15. Hoffert, J., & Schmidt, D. (2009, July). FLEXible Middleware & Transports (FLEXMAT) for Real-

time Event Stream Processing (RT-ESP) Applications. Proceedings of the OMG’s Workshop on Distributed Object Computing for Real-time & Embedded Systems, Washington, D.C., USA.

  • 16. Hoffert, J., Mack, D., & Schmidt, D. (2009, December). Using Machine Learning to Maintain

Pub/Sub System QoS in Dynamic Environments. Proceedings of the 8th Workshop on Adaptive & Reflective Middleware, Urbana Champaign, IL.

  • 17. Hoffert, J., Schmidt, D., & Gokhale, A. (2010, April). Adapting and Evaluating Distributed Real-

time and Embedded Systems in Dynamic Environments,1st International Workshop on Data Dissemination for Large scale Complex Critical Infrastructures, Valencia, Spain

86

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SLIDE 75

Summary of Publications & Presentations (cont.)

First Author

Poster Publications

  • 18. Hoffert, J., Dabholkar, A., Gokhale, A., & Schmidt, D. (2007, March). Enhancing Security in

Ultra-Large Scale (ULS) Systems using Domain-specific Modeling. Spring 2007 Conference for Team for Research in Ubiquitous Secure Technology (TRUST), Berkeley, CA.

  • 19. Hoffert, J., Gokhale, A. & Schmidt, D. (2007, September). QoS Management in

Publish/Subscribe Systems using Domain-specific Modeling. ACM/IEEE 10th International Conference on Model Driven Engineering Languages & Systems (MoDELS), Nashville, TN.

  • 20. Hoffert, J., Schmidt, D., Balakrishnan, M., & Birman, K. (2008, April). Trustworthy Conferencing

via Domain-specific Modeling & Low Latency Reliable Protocols. Spring 2008 Conference for Team for Research in Ubiquitous Secure Technology (TRUST), Berkeley, CA.

  • 21. Hoffert, J. (April, 2010). Evaluating and Adapting QoS for Distributed Real-time & Embedded

Systems in Dynamic Environments, EuroSys 2010 Conference, Paris, France.

87

Tutorials

  • 22. Hoffert, J. (October 2010). Intelligent Event Processing in Quality of Service-Enabled

Publish/Subscribe Middleware, The 2010 International Symposium on Intelligence Information Processing and Trusted Computing, Huanggang, China,

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SLIDE 76

Questions?

88

So Soli li Deo eo Glo Gloria! ia!

Thank you for your time & attention.