고생한 보람.

[수선화]

From: "Eun Young Park" <eypark@cs.kaist.ac.kr>

Date: November 24, 2010 2:17:32 PM GMT+09:00

To: <csall@cs.kaist.ac.kr>

Subject: [PhD defence] 11/26(Fri) 11:00 am - 박선영

전산학과에서는 박사학위 논문심사를 공개하는 것을 원칙으로 하고 있습니다.

이에 아래와 같이 안내하오니 관심 있는 분들의 많은 참석 부탁 드립니다.

 

1. 학과 및 학생명 : 전산학과 박선영

2. 논 문 명  (국문) : 고성능 플래시 저장장치를 위한 소프트웨어 최적화 기법

(영문) : Software Optimization Methods for High-Performance Flash-based Storage

3. abstract :  

Replication is a key technology that enables modern distributed applications to share data. This thesis suggests two building blocks that can facilitate various replication systems.

First, to support efficient implementations of interactive collaborative applications, replicated abstract data types (RADTs) are proposed as building blocks. Collaborative applications highly desire responsive and transparent interactivity, and such interactivity can be achieved with optimistic replication. However, maintaining replica consistency is difficult. Concealing complicated consistency maintenance, RADTs replicate copies of a shared ADT and allow optimistic operations of different orders. In this thesis, a few representative abstract data types (ADTs), such as array, hash table, and growable array (or linked list), are extended into RADTs. Operation commutativity and precedence transitivity are two theoretical principles enabling RADTs to maintain consistency for optimistic operations of RADTs. Especially, precedence transitivity is a practical and efficient way to achieve consistency, for which an s4vector is proposed. Above all, replicated growable arrays (RGAs) can maintain consistency among variable-length ordered objects with insertion/deletion/update operations, which have been highly demanded and studied in collaborative applications for a long time. RGAs make significant improvement in complexity, scalability, and reliability over the effects of the previous approaches. In this dissertation, the experimental results show that the operations of RGAs are more than thousands of times faster than those of the operational transformation methods which have been mainstream approaches for optimistic insertion and deletion.

 

Second, log' (log-prime) version vector is proposed for dynamic replication wherein replicas are frequently created and destroyed.

In replication systems, version vectors are logged with replicas to detect conflicts among operations. Dynamic replications suffer from expensive logging overhead caused by inactive entries. Although the rigmarole of pruning vectors can delete inactive entries, pruned vectors may be incompatible without additional information, which also causes another overhead. Log' version vector consists of only three entries by the mathematic encoding based on the characteristics of prime numbers, and thus can be logged concisely with no pruning technique at a little sacrifice in accuracy. Simulation studies show that log' version vectors are accurate enough to detect almost all conflicts in the replication systems where all replicas are fully synchronizing.

4. 심사위원장 : 맹승렬

5. 심 사 위 원 : 배두환, 허재혁, 이준원(성균관대), 김진수(성균관대)

6. 심 사 일 시 :  2010년 11월 26일(금) 오전 11시 00분

7. 심 사 장 소 :  안영경 세미나실(4420호).  끝.

[수선화]

수서니는 짐을 내려 놓았는가? NO, 그대로 질머지고 있는듯~

[계리미]

축하한다 박선영. 해낼줄 알았다 박산영. 고생했다 박선영. 엄마가 한시름 덜은줄 알았더니 노 란다. 우짜든 짝짝짝 박쑤를 보낸다. ㅎㅎㅎ
그동안 수서니도 고생 많았다. 앞날이 훤히 열릴것이니 맘껏 웃어라.

[양서니]

축하해요 이모^^ 선영인 고생한 얼굴이 아닌데ㅎ 큰일 했으니 앞으로 좋은일만 있길...

[계리미]

즈엄마가 해준 밥 꼬박꼬박 먹어서 오동통 살이 쪘나봐

[sky75]

오~~ 축하한다 선영아...대단하구나 ^^