Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(Cooperative repair). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


University of Texas – Austin

1. -9790-6500. New coding techniques for distributed storage systems: enabling locality, availability and security.

Degree: Electrical and Computer Engineering, 2015, University of Texas – Austin

Distributed storage systems (a.k.a. cloud storage networks) are becoming increasingly important, given the need to put away vast amounts of data that are being generated, analyzed and accessed across multiple disciplines today. Besides serving as backbone systems for large institutions such as CERN, Google and Microsoft, distributed storage systems have been instrumental in the emergence and rapid growth of the modern cloud computing framework. This dissertation takes a coding theoretic approach to address key issues related to designing these systems. First, the problem of enabling efficient mechanisms for restoring the state of the system after storage node failures in considered. In particular, this dissertation studies locally repairable codes that allow for reconstruction of the content stored on a failed node by contacting a small number of intact nodes. Since resilience to permanent loss of the stored information in the event of catastrophic failures is of primary interest in storage systems, explicit constructions for locally repairable codes with optimal minimum distance are presented. This dissertation also designs locally repairable codes that minimize repair-bandwidth, i.e., the amount of data downloaded during a node repair, in addition to the number of intact nodes contributing to the repair process. This dissertation further investigates a generalization of locally repairable codes where codes with the following property are studied: any small set of failed nodes is recoverable from a small number of other intact nodes. This is referred to as cooperative local repair. The main contributions in this regard are bounds on the minimum distance and the dimension of such codes, as well as explicit constructions of families of codes that enable cooperative local repair. The second issue addressed in this dissertation concerns management of hot data, i.e., the frequently accessed information. Towards this, the codes that allow for parallel accesses to information blocks are considered. This part of the dissertation explores the rate vs. minimum distance trade-off for such codes and presents explicit constructions of the codes that have high rate and large minimum distance while supporting (potentially scaling number of) parallel accesses to the stored information. One of the main contributions of the dissertation in this direction is a novel graph theoretic approach to construct batch codes. The batch codes as defined in the literature enable load balancing in a storage system in the sense that multiple requests for information blocks can be served in a parallel manner without downloading too much data from any particular storage node. Finally, this dissertation considers the issue of designing secure coding scheme for distributed storage systems. Given the decentralized nature of these systems and their increasing utilization to store valuable and confidential information, it is desirable that they be resilient against eavesdropping attacks. The problem of characterizing perfect secrecy capacity of… Advisors/Committee Members: Vishwanath, Sriram (advisor), Baccelli, Francois (committee member), Dimakis, Alexandros G (committee member), Mazumdar, Arya (committee member), Zuckerman, David (committee member).

Subjects/Keywords: Coding for distributed storage; Locally repairable codes; Regenerating codes; Code repair; Cooperative repair; Secure distributed storage

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

-9790-6500. (2015). New coding techniques for distributed storage systems: enabling locality, availability and security. (Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/32413

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

-9790-6500. “New coding techniques for distributed storage systems: enabling locality, availability and security.” 2015. Thesis, University of Texas – Austin. Accessed June 24, 2019. http://hdl.handle.net/2152/32413.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

-9790-6500. “New coding techniques for distributed storage systems: enabling locality, availability and security.” 2015. Web. 24 Jun 2019.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-9790-6500. New coding techniques for distributed storage systems: enabling locality, availability and security. [Internet] [Thesis]. University of Texas – Austin; 2015. [cited 2019 Jun 24]. Available from: http://hdl.handle.net/2152/32413.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

-9790-6500. New coding techniques for distributed storage systems: enabling locality, availability and security. [Thesis]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/32413

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

2. Dutta, Atri. Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations.

Degree: PhD, Aerospace Engineering, 2009, Georgia Tech

On-orbit servicing (OOS) of space systems provides immense benefits by extending their lifetime, by reducing overall cost of space operations, and by adding flexibility to space missions. Refueling is an important aspect of OOS operations. The problem of determining the optimal strategy of refueling multiple satellites in a constellation, by expending minimum fuel during the orbital transfers, is challenging, and requires the solution of a large-scale optimization problem. The conventional notion about a refueling mission is to have a service vehicle visit all fuel-deficient satellites one by one and deliver fuel to them. A recently emerged concept, known as the peer-to-peer (P2P) strategy, is a distributed method of replenishing satellites with fuel. P2P strategy is an integral part of a mixed refueling strategy, in which a service vehicle delivers fuel to part (perhaps half) of the satellites in the constellation, and these satellites, in turn, engage in P2P maneuvers with the remaining satellites. During a P2P maneuver between a fuel-sufficient and a fuel-deficient satellite, one of them performs an orbital transfer to rendezvous with the other, exchanges fuel, and then returns back to its original orbital position. In terms of fuel expended during the refueling process, the mixed strategy outperforms the single service vehicle strategy, particularly with increasing number of satellites in the constellation. This dissertation looks at the problem of P2P refueling problem and proposes new extensions like the Cooperative P2P and Egalitarian P2P strategies. It presents an overview of the methodologies developed to determine the optimal set of orbital transfers required for cooperative and non-cooperative P2P refueling strategies. Results demonstrate that the proposed strategies help in reducing fuel expenditure during the refueling process. Advisors/Committee Members: Panagiotis Tsiotras (Committee Chair), Eric Feron (Committee Member), Joseph Saleh (Committee Member), Ryan Russell (Committee Member), William Cook (Committee Member).

Subjects/Keywords: Constellation graphs; Three-index assignment problem; NP-hardness; Network flows; Cooperative rendezvous; On-orbit servicing; Satellite refueling; Peer-to-peer refueling; Lambert's problem; Hohmann transfers; Phasing maneuvers; Artificial satellites Refueling; Artificial satellites Orbits; Artificial satellites Maintenance and repair; Mathematical optimization

COOPERATIVE EGALITARIAN PEER-TO-PEER REFUELING STRATEGY… …Cooperative rendezvous for the case ri ≤ r ≤ ro . . . . . . . . . . . . . 31 12 Variation of HHCM… …Cooperative Maneuver (r⋆ = ro ). . . . . . . . . . . 37 15 Cooperative rendezvous… …x28;ri = 1, ro = 1.05). . . . . . . . . . 51 22 Optimal cooperative (but non… …Cooperative P2P and Egalitarian P2P strategies. It presents an overview of the methodologies… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Dutta, A. (2009). Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28082

Chicago Manual of Style (16th Edition):

Dutta, Atri. “Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations.” 2009. Doctoral Dissertation, Georgia Tech. Accessed June 24, 2019. http://hdl.handle.net/1853/28082.

MLA Handbook (7th Edition):

Dutta, Atri. “Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations.” 2009. Web. 24 Jun 2019.

Vancouver:

Dutta A. Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2019 Jun 24]. Available from: http://hdl.handle.net/1853/28082.

Council of Science Editors:

Dutta A. Optimal cooperative and non-cooperative peer-to-peer maneuvers for refueling satellites in circular constellations. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/28082

.