개미알고리즘을 이용한 드론의 제설 경로 최적화

학위논문(석사) -- 서울대학교대학원 : 공과대학 건설환경공학부, 2022.2. 김동규.Drones can overcome the limitation of ground vehicles by replacing the congestion time and allowing rapid service. For sudden snowfall with climate change, a quickly deployed drone can be a flexible alternative considering the deadhead route and the labor costs. The goal of this study is to optimize a drone arc routing problem (D-ARP), servicing the required roads for snow removal. A D-ARP creates computational burden especially in large network. The D-ARP has a large search space due to its exponentially increased candidate route, arc direction decision, and continuous arc space. To reduce the search space, we developed the auxiliary transformation method in ACO algorithm and adopted the random walk method. The contribution of the work is introducing a new problem and optimization approach of D-ARP in snow removal operation and reduce its search space. The optimization results confirmed that the drone travels shorter distance compared to the truck with a reduction of 5% to 22%. Furthermore, even under the length constraint model, the drone shows 4% reduction compared to the truck. The result of the test sets demonstrated that the adopted heuristic algorithm performs well in the large size networks in reasonable time. Based on the results, introducing a drone in snow removal is expected to save the operation cost in practical terms.드론은 혼잡시간대를 대체하고 빠른 서비스를 가능하게 함으로써 지상차량의 한계를 극복할 수 있다. 최근 기후변화에 따른 갑작스런 강설의 경우에, 드론과 같이 빠르게 투입할 수 있는 서비스는 운행 경로와 노동비용을 고려했을 때도 유연한 운영 옵션이 될 수 있다. 본 연구의 목적은 드론 아크 라우팅(D-ARP)을 최적화하는 것이며, 이는 제설에 필요한 도로를 서비스하는 경로를 탐색하는 것이다. 드론 아크 라우팅은 특히 큰 네트워크에서 컴퓨터 부하를 생성한다. 다시 말해D-ARP는 큰 검색공간을 필요로 하며, 이는 기하급수적으로 증가하는 후보 경로 및 호의 방향 결정 그리고 연속적인 호의 공간으로부터 기인한다. 검색공간을 줄이기 위해, 우리는 개미알고리즘에 보조변환방법을 적용하는 방안을 도입하였으며 또한 랜덤워크 기법을 채택하였다. 본 연구의 기여는 제설 운영에 있어 D-ARP라는 새로운 문제를 설정하고 최적화 접근법을 도입하였으며 검색공간을 최소화한 것이다. 최적화 결과, 드론은 지상트럭에 비해 약 5% ~ 22%의 경로 비용 감소를 보였다. 나아가 길이 제약 모델에서도 드론은 4%의 비용 감소를 보였다. 또한 실험결과는 적용한 휴리스틱 알고리즘이 큰 네트워크에서도 합리적 시간 내에 최적해를 찾음을 입증하였다. 이러한 결과를 바탕으로, 드론을 제설에 도입하는 것은 미래에 제설 운영 비용을 실질적으로 감소시킬 것으로 기대된다.Chapter 1. Introduction 4 1.1. Study Background 4 1.2. Purpose of Research 6 Chapter 2. Literature Review 7 2.1. Drone Arc Routing problem 7 2.2. Snow Removal Routing Problem 8 2.3. The Classic ARPs and Algorithms 9 2.4. Large Search Space and Arc direction 11 Chapter 3. Method 13 3.1. Problem Statement 13 3.2. Formulation 16 Chapter 4. Algorithm 17 4.1. Overview 17 4.2. Auxilary Transformation Method 18 4.3. Ant Colony Optimization (ACO) 20 4.4. Post Process for Arc Direction Decision 23 4.5. Length Constraint and Random Walk 24 Chapter 5. Results 27 5.1. Application in Toy Network 27 5.2. Application in Real-world Networks 29 5.3. Application of the Refill Constraint in Seoul 31 Chapter 6. Conclusion 34 References 35 Acknowledgment 40석

Prometno-tehnološka optimizacija faze uručenja poštanskih pošiljaka

Technological phase end-delivery represents the most expensive activity of postal traffic. By identifying user requirements and separating it as a distinguished holistic system and process it is possible to identify factors which affect efficiency and effectiveness regarding handing over and delivery of postal items. End-delivery has decisive effect on quality beacuse as a service subsystem directly represents postal service to end users. Postal services are performed by using public or autonomous postal network. Systematic modeling of delivery districts, application of mathematical and heuristic methods with adaptation of intelligent transportation solutions optimize network and everyday operational costs.Tehnološka faza uručenja predstavlja najskuplju aktivnost odvijanja poštanskog prometa. Prepoznavanjem korisničkih zahtjeva uz postavljanje uručenja kao izdvojenog holističkog sustava i procesa moguće je utvrditi čimbenike koji utječu na učinkovitost te djelotvornost dostave i isporuke poštanskih pošiljaka. Uručenje ima presudan utjecaj na kvalitetu jer kao uslužni podsustav direktno predstavlja poštansku djelatnost krajnjim korisnicima. Poštanske usluge se obavljaju korištenjem javne ili autonomne poštanske mreže. Sustavno modeliranje dostavnih rajona, primjena matematičkih i heurističkih metoda uz adaptaciju inteligentnih transportnih rješenja optimiziraju mrežu te svakodnevne operativne troškove

Optimisation for Large-scale Maintenance, Scheduling and Vehicle Routing Problems

Solving real-world combinatorial problems is involved in many industry fields to minimise operational cost or to maximise profit, or both. Along with continuous growth in computing power, many asset management decision-making processes that were originally solved by hand now tend to be based on big data analysis. Larger scale problem can be solved and more detailed operation instructions can be delivered. In this thesis, we investigate models and algorithms to solve large scale Geographically Distributed asset Maintenance Problems (GDMP). Our study of the problem was motivated by our business partner, Gaist solutions Ltd., to optimise scheduling of maintenance actions for a drainage system in an urban area. The models and solution methods proposed in the thesis can be applied to many similar issues arising in other industry fields. The thesis contains three parts. We firstly built a risk driven model considering vehicle routing problems and the asset degradation information. A hyperheuristic method embedded with customised low-level heuristics is employed to solve our real-world drainage maintenance problem in Blackpool. Computational results show that our hyperheuristic approach can, within reasonable CPU time, produce much higher quality solutions than the scheduling strategy currently implemented by Blackpool council. We then attempt to develop more efficient solution approaches to tackle our GDMP. We study various hyperheuristics and propose efficient local search strategies in part II. We present computational results on standard periodic vehicle routing problem instances and our GDMP instances. Based on manifold experimental evidences, we summarise the principles of designing heuristic based solution approaches to solve combinatorial problems. Last bu not least, we investigate a related decision making problem from highway maintenance, that is again of interest to Gaist solutions Ltd. We aim to make a strategical decision to choose a cost effective method of delivering the road inspection at a national scale. We build the analysis based on the Chinese Postman Problem and theoretically proof the modelling feasibility in real-world road inspection situations. We also propose a novel graph reduction process to allow effective computation over very large data sets

Diseño de un sistema de recogida de residuos urbanos : enfoque multiobjetivo y uso de metaheurísticos

En este trabajo se desarrolla un método para resolver el problema de diseño de rutas, a lo largo de un horizonte de planificación predeterminado, para la recogida de la fracción orgánica residuos urbanos en un entorno rural. El objetivo en este problema es doble: minimizar el coste de las operaciones de rutas y mejorar el nivel de calidad, por lo que se adapta a un problema biobjetivo. Para resolver el problema se diseña un método ad hoc basado en estrategias heurísticas. Éste, sigue las ideas de la estrategia MOAMP, diseñada para problemas multi-objetivo. A continuación, y desde el punto de vista metodológico, se desarrollan estrategias de aceleración para algunos de los procedimientos del método propuesto. Por último, se compara, tanto en instancias reales como ficticias, con una adaptación a este problema, de una variante de un algoritmo genético, conocida como NSGA I

Traveling Salesman Problem

This book is a collection of current research in the application of evolutionary algorithms and other optimal algorithms to solving the TSP problem. It brings together researchers with applications in Artificial Immune Systems, Genetic Algorithms, Neural Networks and Differential Evolution Algorithm. Hybrid systems, like Fuzzy Maps, Chaotic Maps and Parallelized TSP are also presented. Most importantly, this book presents both theoretical as well as practical applications of TSP, which will be a vital tool for researchers and graduate entry students in the field of applied Mathematics, Computing Science and Engineering

A Polyhedral Study of Mixed 0-1 Set

We consider a variant of the well-known single node fixed charge network flow set with constant capacities. This set arises from the relaxation of more general mixed integer sets such as lot-sizing problems with multiple suppliers. We provide a complete polyhedral characterization of the convex hull of the given set

Zhang Tianyi: Critical analysis of his development as a writer of fiction.

Born in 1906 in Nanjing, Zhang began writing in his teens for "Mandarin Duck and Butterfly" magazines in Shanghai. After 1929, he wrote short stories, middle-length stories, novels and two plays, all in a realistic style. The eighty-odd short stories Zhang wrote between 1929 and 1938 provided the basis for his reputation as a writer of fiction in the pre-liberation period. After 1938, Zhang concentrated on writing literary criticism and theory and after contracting tuberculosis in 1942 he all but stopped writing. Upon the establishment of the Communist republic in 1949 Zhang was assigned to several posts in the literary leadership and wrote a few didactic works for children as well as theoretical and critical articles. He wrote nothing of note after 1960 and his health deteriorated after suffering a stroke in 1975. Zhang died on 28 April, 1985, This thesis considers Zhang's development as a writer of fiction, concentrating attention on the period 1929 to 1938 when Zhang produced his most noteworthy works, but also analysing the place in his career of the recently rediscovered stories written between 1922 and 1928. Zhang's critical and theoretical writings are considered for what they reveal of his literary ideals and are considered as an index to Zhang's success as a writer of fiction. Zhang's development as a writer of fiction is considered chronologically and contemporary political, historical, social and literary influences are alluded to whenever pertinent. Zhang's short stories are also measured against the yardstick of Western practice in the writing of short stories and conventional and unconventional uses of the genre by Zhang are pointed out. Appendices contain a biographical entry about Zhang written in the light of recently published material about Zhang's life and interviews with his family and friends; together with translations of several previously untranslated stories by Zhang