Search button


Filter

Date Range:


From: To:


View all
Categories:

  • Graduate Student Center Graduate Student Center
  • General Public Presentations General Public Presentations
  • Thesis/Dissertation Seminars Thesis/Dissertation Seminars
  • Arts and Humanities Seminars Arts and Humanities Seminars
  • Education Seminars Education Seminars
  • Health Professions Seminars Health Professions Seminars
  • Professional/Business Seminars Professional/Business Seminars
  • Social Sciences Seminars Social Sciences Seminars
  • STEM* Seminars STEM* Seminars
  • Social Events Social Events
  • Student and Professional Development Student and Professional Development
  • Informational Events Informational Events
  • Important Dates Important Dates

*STEM: Science, Technology, Engineering, and Mathematics

Audience:
Faculty
Staff
Students
International Community



Events Calendar   

Back to Summary

Thesis/Dissertation Seminars

Dissertation Defense: Adaptive Architectural Strategies for Resilient Energy-Aware Computing

HEC 356
May 13, 2015 @ 10:30 AM - 12:30 PM

Announcing the Final Examination of Rizwan Arshad Ashraf for the degree of Doctor of Philosophy

Reconfigurable logic or Field-Programmable Gate Array (FPGA) devices have the ability to dynamically adapt the computational circuit based on user-specified or operating-condition requirements. Such hardware platforms are utilized in this dissertation to develop adaptive techniques for achieving reliable and sustainable operation while autonomously meeting these requirements. In particular, the properties of resource uniformity and in-field reconfiguration via on-chip processors are exploited to implement Evolvable Hardware (EHW). EHW utilize genetic algorithms to realize logic circuits at runtime, as directed by the objective function. However, the size of problems solved using EHW as compared with traditional approaches has been limited to relatively compact circuits. This is due to the increase in complexity of the genetic algorithm with increase in circuit size. To address this research challenge of scalability, the Netlist-Driven Evolutionary Refurbishment (NDER) technique was designed and implemented to enable on-the-fly permanent fault mitigation in FPGA circuits. NDER has been shown to achieve refurbishment of relatively large sized benchmark circuits as compared to related works. Additionally, Design Diversity (DD) techniques which are used to aid such evolutionary refurbishment techniques are also proposed and the efficacy of various DD techniques is quantified and evaluated.

Ensuring operational reliability in the presence of Process, Voltage, and Temperature (PVT) variations owing to decreased feature sizes to enable higher integration and performance levels has incurred a substantial increase in design guardbands. Thus, there is a need for adaptable logic datapaths in custom-designed nanometer-scale ICs. To address this challenge, the circuit-level technique of Self-Recovery Enabled Logic (SREL) was designed. At design-time, vulnerable portions of the circuit identified using conventional Electronic Design Automation tools are replicated to provide post-fabrication adaptability via intelligent techniques. In-situ timing sensors are utilized in a feedback loop to activate suitable datapaths based on current conditions that optimize performance and energy. Primarily, SREL is able to mitigate the timing degradations caused due to transistor aging effects in sub-micron devices by reducing the stress induced by active elements. As a result, fewer guardbands need to be included to achieve comparable performance levels which leads to considerable energy savings over the operational lifetime.

The need for energy-efficient operation in current computing systems has given rise to Near-Threshold Computing as opposed to the conventional approach of operating devices at nominal voltage. In particular, the goal of exascale computing initiative in High Performance Computing (HPC) is to achieve 1 EFLOPS under the power budget of 20MW. However, it comes at the cost of increased reliability concerns, such as the increase in performance variations and soft errors. This has given rise to increased resiliency requirements for HPC applications in terms of ensuring functionality within given error thresholds while operating at lower voltages. My dissertation research devised techniques and tools to quantify the effects of radiation-induced transient faults in distributed applications on large-scale systems. A combination of compiler-level code transformation and instrumentation are employed for runtime monitoring to assess the speed and depth of application state corruption as a result of fault injection. Finally, fault propagation models are derived for each HPC application that can be used to estimate the number of corrupted memory locations at runtime. Additionally, the tradeoffs between performance and vulnerability and the causal relations between compiler optimization and application vulnerability are investigated.


 

 
     ->
 

Graduate News

Office Hours

Monday - Friday 9:00am - 5:00pm

Contact Information

Campus Address:
Millican Hall, Suite 230
4000 Central Florida Blvd.
Orlando, FL 32816
Phone: 407-823-2766
Fax: 407-823-6442
Mailing Address:
P.O. Box 160112, Orlando, FL 32816-0112

UCF Stands for Opportunity

 

The University of Central Florida is accredited by the Southern Association of Colleges and Schools Commission on Colleges (SACSCOC) to award degrees at the associate, baccalaureate, master’s, specialist, and doctoral levels. Contact the Commission on Colleges at 1866 Southern Lane, Decatur, Georgia 30033-4097 or call (404) 679-4500 for questions about the accreditation of the University of Central Florida.

Please note the commission's expectation that contact occur only if there is evidence to support significant non-compliance with a requirement or standard. For other information about UCF’s SACSCOC accreditation, please contact the university's SACSCOC liaison in UCF's Office of Academic Affairs.

| © 2015 University of Central Florida - College of Graduate Studies