Recycling the Optimized Machine Codes Generated by JavaScript Engine

학위논문 (석사)-- 서울대학교 대학원 공과대학 전기·정보공학부, 2017. 8. 문수묵.자바스크립트의 역할이 계속해서 증대되고 있으며, 자바스크립트 엔진의 성능이 중요한 이슈가 되고 있다. 본 논문은 자바스크립트 엔진의 성능을 향상하기 위한 방법으로 다단계(multi-tiered) JIT 컴파일 엔진에서 최적화 JIT 컴파일러가 생성하는 기계어 코드를 재활용하는 방식을 제안한다. 이 방식에서는 최적화 JIT 컴파일러가 생성하는 기계어 코드를 파일에 저장하였다가 다음 프로그램 수행에서 이를 재사용한다. 그리하여 엔진에서 컴파일 오버헤드를 제거하고 시작부터 양질의 코드를 사용하게 만든다. 기계어 코드를 재사용하기 위해서는 코드 내의 포인터들을 현재 수행에 맞게 패치 해주어야 하는데, 이를 위하여 기계어 코드와 함께 코드 내의 포인터 위치 및 포인터가 가리키는 객체의 정체를 같이 저장하는 테이블을 생성, 저장한다. 최적화 JIT 컴파일러에서는 베이스라인 JIT 에서와는 달리 완성된 테이블을 만들기 위해 최적화 과정 중에서 파생적으로 생성되는 포인터와 프로파일에 의해 고정 생성되는 포인터들까지 찾아서 처리해야 한다. 전자는 최적화 과정을 같이 따라가면서, 후자는 컴파일러가 포인터를 고정 생성하지 못하도록 바꾸어 처리한다. 이를 실제 자바스크립트 엔진 중의 하나인 JavaScriptCore 엔진에서 적용한 결과, 사용자가 선택적으로 이득이 되는 기계어 코드들만 재사용 했을 시 최대 29%, 평균 11%의 성능 향상이 있었다.제 1 장 서 론 1 제 2 장 자바스크립트 엔진의 구조 3 제 1 절 자바스크립트 엔진 3 제 2 절 최적화 JIT 컴파일러와 Profile 5 제 3 절 WebKit의 JavaScriptCore 7 제 3 장 최적화된 기계어 코드의 재활용 8 제 1 절 개요 8 제 2 절 포인터 패칭 9 제 3 절 최적화 과정과 포인터 생성 10 제 4 절 Profile과 포인터 생성 12 제 5 절 선택적인 재활용 14 제 4 장 실험 결과 및 분석 16 제 1 절 실행 환경 16 제 2 절 실험 결과 16 제 3 절 관찰 결과 17 제 5 장 결론 및 향후 연구 18 참고문헌 19 Abstract 20Maste

The effect of the previous arthroscopic proximal realignment performed in the skeletally immature on the result of the anteromedial tibial tuberosity transfer

Dept. of Medicine/석사Purpose: This study aims to evaluate the effect of the previous arthroscopic proximal realignment performed in the skeletally immature on the result of the anteromedial tibial tuberosity transfer(AMTT) by comparison the result of the staged operation which performed the AMTT at skeletally mature after arthroscopic proximal realignment at skeletally immature with the result of the delayed operation which performed the AMTT after the conservative treatment in the patients with recurrent patella dislocation had developed at skeletally immature.Method: We retrospectively reviewed the recorded of 412 patients (436 knees) who had diagnosed with recurrent patella dislocation from March 2001 to April 2009. Patients were categorized into two groups which had the AMTT at the skeletally mature after the previous arthroscopic medial plication and lateral release in the skeletally immature (Group S: 26 knees) and after the conservative management (Group D: 18 knees) to recurrent patella dislocation in the skeletally immature. Functional scores were assessed using the Lysholm score, the Kujala score and Tenger score. Clinical outcomes were determined from the data obtained before surgery and at the last follow-up visit.Result: There were no significant difference between the groups with regard to the demographic evaluation except the average number of dislocations before the AMTT (P<0.01) and the average span from dislocation after the primary management to the AMTT (P<0.01). There was improvement to radiologic indicator (average congruence angle, average of lateral patellofemoral angle, Insall-Salvati ratio, Tibial tuberosity-trochlear groove distance) between the preoperative and the last follow-up in both the groups. There was no significant difference between two groups regarding to radiologic indicator. Substantial improvement in Lysholm, Kujala scores, and Tenger score between the preoperative and the last follow-up were observed in both the groups. There were significant differences in Lysholm score (Group D 80.3 ± 6.0, Group S 85.5 ± 6.5), Kujala score(Group D 86.6 ± 3.9, Group S 86.6 ± 3.9), and Tenger score (Group D 5.7 ± 1.5, Group S 6.7 ± 1.4) between the groups at last follow-up (Lysholm score: P=0.012, Kujala score: P< 0.01, Tenger score: P=0.032).Conclusion: The AMTT after the previous arthroscopic proximal realignment performed in the skeletally immature had better satisfactory clinical results than the AMTT after the conservative management to the recurrent patella dislocation developed at skeletally immature. Sequence of arthroscopic proximal realignment in skeletally immature and the AMTT after closing the physis of the knee might be good option to manage to recurrent patella dislocation in skeletally immature.ope

Treatment of Anterior Glenoid Rim Fracture with Comminuted Fragment Using Arthroscopic Reduction and AO Headless Compression Screw Fixation - A Case Report -

Purpose: We present a case of anterior glenoid rim comminuted fracture that was treated with arthroscopic reduction and an AO headless compression screw (HCS) fixation. Materials and Methods: A 31-year old man complained of left shoulder pain after falling down on stairs. The anterior glenoid comminuted fragments were arthroscopically reduced. Fixation with an AO HCS was done after placement of 1.1 mm Kirschner wire as a guide pin through a standard cannulated anterosuperior portal. Results: Twelve months after the operation, union of the fracture was achieved and the range of motion was fully recovered. He did not complain of any discomfort during his activities of daily living. Conclusion: An AO HCS had various screw sizes and this was good for fixation of a small glenoid fracture and a long drill bit and screw driver were useful for fixation of deep seated glenoid fracture. A short guide wire could be replaced by a 1.1 mm K-wire. An AO HCS was useful for fixation of an anterior glenoid rim comminuted fracture.ope

CC-NUMA-RC 다중 프로세서 시스템에서 사전 통신에 관한 연구

학위논문(석사)--서울대학교 대학원 :컴퓨터공학과,1999.Maste

Biportal endoscopic debridement and percutaneous screw fixation technique for spinal tuberculosis: how I do it

Background: Biportal endoscopy and percutaneous screw fixation are promising techniques that can be applied to treat various degenerative spinal diseases. However, these techniques for spinal tuberculosis have not been reported. Method: Using the biportal endoscopic technique, bilateral decompression, tissue biopsy, and granulation tissue removal were performed using the screw insertion site. Using the percutaneous fixation screw technique, posterior stabilization and sagittal angle restoration were achieved. Paraplegia and radiating pain improved neurologically. Kyphosis was radiologically restored. Spinal tuberculosis (Potts's disease) was histopathologically diagnosed. Conclusion: Minimally invasive endoscopic and percutaneous screw technique can aid the diagnosis and treatment of spinal tuberculosis.restrictio