공항 게이트 할당 문제에 대한 근사 동적 계획법

학위논문(석사) -- 서울대학교대학원 : 공과대학 산업공학과, 2023. 8. 이경식.In real-world airport gate assignment problem (AGAP), the planning of flight-to-gate assignments involves more than a thousand of flights and is subject to frequent real-time adjustments. Thus, an efficient solution approach for AGAP is required for airport operation in practice. Here, we propose an approximate dynamic programming (ADP) approach for AGAP. In our ADP approach, value function is approximated by the interpolation of upper bound and lower bound of true value function with consideration of lookahead horizon. Heuristic algorithms and the linear programming relaxation values of integer programming (IP) models for AGAP are used for the upper bound and the lower bound, respectively. We first compare the bounds for several IP models and show that the pattern-based model provides the strongest bound, whose size is exponential to the input size. Next, we propose an efficient column generation method and ADP acceleration techniques to over the computational complexity arising when using the pattern-based model. The effectiveness and practicality of our ADP approach were demonstrated by computational experiments.본 연구에서는 공항 운영상의 제약을 고려하여 항공기를 게이트에 적절히 배분하는 공항 게이트 할당 문제를 다룬다. 현실에서는 많은 수의 항공기와 게이트를 고려해야 하고, 동시에 상황 변화에 따른 계획의 재수립이 빈번하여, 이에 유연하고 신속하게 대처할 수 있는 효율적인 방법이 필요하다. 이를 위해 본 연구에서는 전방 탐색 길이를 고려한 근사동적계획 해법을 제안한다. 근사동적계획법에서 가치함수를 추정하기 위해 패턴기반모형의 선형계획완화문제의 하한을 활용한다. 패턴기반모형은 강한 하한을 제공하나 지수적으로 많은 개수의 변수를 가지고 있어 이 모형을 활용할 시 매우 큰 계산적 부담이 발생한다. 이 문제점을 극복하기 위해 효율적인 열생성 방법 및 근사동적계획 가속화 기법을 제안한다. 다양한 실험을 통해 열생성 방법 및 근사동적계획 가속화 기법의 효과성을 확인하였다. 그리고 실제 데이터에 기반한 실험을 통하여 제안한 해법이 기존 방법 대비 합리적인 시간 내에 좋은 성능의 해를 제공하는 것을 확인하였다.1 Introduction 1 1.1 Background, 1 1.2 Literature Review, 4 1.2.1 Airport Gate Assignment Problem, 4 1.2.2 Related Problems, 5 1.2.3 Approximate Dynamic Programming, 7 1.3 Motivation and Contributions, 9 1.4 Organization of the Thesis, 10 2 Dynamic Programming Formulation and Approximate Dynamic Programming Approach for AGAP 11 2.1 Problem Definition, 12 2.2 Dynamic Programming Formulation,13 2.3 Approximate Dynamic Programming Approach,16 2.4 IP Models for AGAP and Comparison of Bounds, 20 2.4.1 Basic Model, 20 2.4.2 Network Model, 21 2.4.3 Pattern-based Model, 22 2.4.4 Comparison of Bounds, 24 3 Approximate Dynamic Programming Approach using Pattern-based Model 28 3.1 Solution Approach for Action Evaluation Problem, 29 3.1.1 Column Generation Method for Action Evaluation Problem, 29 3.1.2 Solution Approach for Subproblem, 33 3.1.3 Multiple Column Generation Strategy, 35 3.2 ADP Acceleration Techniques, 37 3.2.1 Early Fixing, 38 3.2.2 Reordering of Action Sequence, 39 3.2.3 Early Cut-off, 40 3.3 Implementation Details, 42 3.3.1 Initialization, 42 3.3.2 Column Inheritance, 42 3.3.3 Updating Bounds & Termination Criterion, 43 4 Computational Experiments 45 4.1 Experiment Setting, 46 4.2 Effects of Algorithmic Parameters of ADP(P, η, τ ), 48 4.2.1 Sensitivity Analysis on the Value of Interpolation Ratio, 48 4.2.2 Effects of the ADP Acceleration Techniques, 49 4.2.3 Scalability Test with respect to Parameters τ , 52 4.3 Performance of ADP(P, η, τ ), 55 4.3.1 Test on Artificial Data, 56 4.3.2 Test on Real-world Data, 58 5 Conclusion 60석

Results of Treatment in 33 Patients with Neuroblastoma

의학과/석사[영문] [한글] 신경아세포종(神經芽細胞腫)은 소아에서 중추신경계의 종양 다음으로 흔한 악성종양이 며, 면역기전 및 자연퇴행 등의 특성을 보이고 있다. 저자는 1974년 9월부터 1980년 9월 까지 약 6년간 연세 암센터 및 연세의대부속 세브란스병원 소아과에서 진단 및 치료받은 33명의 신경아세포종 환아에 대하여 임상연구 및 생존율을 산정하였다. 남여의 비는 1.2:1로 남아에 약간 더 많았고, 2세미만이 33.3%였으며 평균연령은 4.1 ± 3.5세였다. 진단당시 병기는 제Ⅳ기가 57.6%로 가장 많았으며, 일반적으로 연령이 많은 환자는 내 원 당시부터 전이가 있는 경향을 보였다. 원발부위는 복부가 17예 (51.5%) 로 가장 많았고, 전이는 골(骨)전이가 9예 (42.9%)로 가장 많았다. 7예는 현재 2년이상 추적 관찰되고 있으며, 이들은 완치된 것으로 사료된다. 현재 추적중인 11예는 거의가 외과적 절제나 방사선 치료를 받았다. 생명표 방식에 의거하여 산정한 전체 환아의 생존율은 6개월에 77%, 12개월에 63%, 18 개월 이후는 45%였다. Results of Treatment in 33 Patients with Neuroblastoma Hak Yong Kim Department of Medical Science The Graduate School Yonsei University (Directed by Professor Duk Jin Yun, M.D.) Neuroblastoma is a malignant neoplasm which arises from primitive sympathetic neuroblasts. It is the second most common solid tumor in young children exceeded in incidence only by brain tumors. This tumor shows immunological features and spontaneous regression. But in spite of recent advances in multimodality therapy, survival rate has not been improved much. Thirty-three patients with neuroblastoma were reviewed who had been diagnosed and treated between 1974 and 1980, and survival rate was calculated by life table method. The results of this study may be summarized briefly as follows : 1. Of the 33 patients, 18 were male and 15 were female. Their age ranged from 25 days to 13(11/12) years(mean 4.1±3.5 years). About 33 per cent of them were below 2 years. 2. Stage at the time of diagnosis showed that the patient with stage Ⅳ were most frequent(57.6%). Generally the older patients tended to have more frequent metastasis than the younger ones at the time of their first visit. 3. Abdomen was the most frequent prima교 tumor site(17 of 33 patients, 51.5%), and bone was the most frequent metastatic site(9 of 21 patients, 42.9%). 4. Seven cartes are new on the follow-up list more than 2 years and have been considered cured. 5. Most of the 11 cases whose progress has been closely followed had received surgical excision or radiotherapy. 6. Ganglioneuroblastoma was present in 2 cases, and they are alive now since the time of diagnosis. 7. Survival rate of total 33 patients calculated by life table method was 77 per cent at 6th month, 63 per cent at 12th month, and 45 per cent after 18th month.restrictio

끈상 접촉여재를 이용한 하천정화 방안

학위논문(석사)--亞州大學校 産業大學院 :環境工學科,2000textMaste

Fizeau interferometry using angled end-face optical fiber source

피조 간섭계의 측정 정밀도를 향상시키기 위해서 광 분할기를 제거한 형태의 피조 간섭계를 구현했다. 단일 모드 광섬유를 구면파 광원으로 사용했고 끝 단을 반사면으로 만들기 위해서 경면 가공했다. 반사면은 적당한 각도로 경사지게 가공되어 있는데 이것은 간섭무늬의 CCD관찰을 용이하게 한다. 경사 단면 광섬유 광원을 이용한 피조 간섭계는 기존의 피조 간섭계에서 구면파를 왜곡시키는 광 분할기를 제거함으로써 측정 정밀도를 향상시킬 수 있었다 또한 동일한 시편의 측정결과를 비교함으로써 기존의 피조 간섭계로부터 개선된 정밀도를 정량적으로 구할 수 있었다. 그리고 경사 단면 광섬유 광원의 구면파정도를 알아보기 위해서 PS/PDI(Phase Shifting/Point Diffraction Interferometer)를 구현함으로써 광원의 구면파 정도를 실험적으로 검증했다

광학계 평가용 광섬유 점회절 간섭계

학위논문(박사) - 한국과학기술원 : 기계공학전공, 2005.2, [ ix, 73 p. ]Interferometry for optical testing has evolved according to the industrial demands such as semiconductor or large-scale optics and there are still some challenges that the interferometric metrology should solve. They are aspheric optics testing, highly accurate and environmentally robust measurement. This thesis is devoted to solve those problems and propose new interferometers with higher accuracy and vibration insensibility. In an effort to make more accurate interferometer, the oblique fiber optic diffraction interferometer was developed. And as a vibration insensitive interferometer, the fringe-stabilized fiber optic diffraction interferometer is presented. The main idea or key component of those interferometers is commonly a single-mode fiber. Optical fiber has various applications and full field optical testing interferometers found breakthroughs in single-mode fibers since they were known to generate near-perfect spherical waves. Wavefront sphericity from single-mode fibers, however, has not been thoroughly investigated enough to verify their uses in high precision metrology. This thesis deals with those issues in theoretical and experimental points of view, and some practical matters about the fabrication of the single-mode fiber source are included. In addition, nonparaxial Fresnel diffraction formula is derived, which predicts the diffraction field from single-mode fibers with unprecedented accuracy other than numerical solutions. The oblique fiber optic diffraction interferometer is presented as an application of the oblique fiber source and a large scale spherical mirror was successfully tested. Next, the fringe-stabilized fiber optic diffraction interferometer is proposed as a promising solution to the vibration insensitive on-machine measurement. Actual embodiment and some measurement results are presented.한국과학기술원 : 기계공학전공