Multi-objective routing and scheduling for airport ground movement

Recent research on airport ground movement introduced an Active Routing framework to support multi-objective trajectory-based operations. This results in edges in the airport taxiway graph having multiple costs such as taxi time, fuel consumption and emissions. In such a graph, multiple edges exist between two nodes reflecting different trade-offs among the multiple costs. Aircraft will have to choose the most efficient edge from multiple edges in order to traverse from one node to another respecting various operational constraints. In this paper, we introduce a multi-objective routing and scheduling algorithm based on the enumerative approach that can be used to solve such a multi-objective multi-graph problem. Results using the proposed algorithm for a range of international airports are presented. Compared with other routing and scheduling algorithms, the proposed algorithm can find a representative set of optimal or near optimal solutions in a single run when the sequence of aircraft is fixed. In order to accelerate the search, heuristic functions and a preference-based approach are introduced. We analyse the performance of different approaches and discuss how the structure of the multi-graph affects computational complexity and quality of solutions

공급네트워크 복원력에 대한 통합 모델: 역량, 교환 관계 및 네트워크 속성

학위논문 (박사)-- 서울대학교 대학원 : 경영대학 경영학과, 2018. 2. 박상욱.The supply chain management (SCM) activities and its performance become vulnerable due to sudden disruptive events in the business process. Specifically, among three phases (sense, respond, recover) supply chain (SC) experience under disruption, we are interested in post-event recovery activities. For example, after the supply disruption, firms must transfer equipment and switch production to alternative or new suppliers utilizing network capability and flexibility. Such recovery activities are termed as resilience activities or a term, SC resilience. The primary objective of this thesis is to thoroughly investigate all the important attributes related to SC resilience, and to propose a comprehensive scheme to show the level of resilience among multiple firms from a network perspective. This thesis considers three problems in a sequential manner so that the critical issues fostering SC resilience can be practically resolved: (1) to determine the critical attributes for SC resilience(2) to present a network-based structure for managing the levels of resilienceand (3) to propose comprehensive network resilience model for both deterministic and probabilistic situations. This thesis first elicits important resilience attributes, among which a number of determinant attributes are critical for supply chain sustainability. The resilience capabilities introduced in the existing literature are systematically investigated and classified, based on a value hierarchy. A survey study is then conducted in order to validate the important exchange relationship attributes and supply chain capabilities. Second, a graphical representation is proposed to visualize the resilience relationship in a network formation. A node here represents a partner firms resilience capability in the supply network and the network value consists of the positional value of the firm. We then adopt an outranking methodology, concordance discordance approach, to provide a process to identify the improvement priority order. Finally, a total network resilience model is proposed to handle resilience levels and interrelationships of the firms simultaneously. The proposed model is also extended to serve as a probabilistic model, along with a number of sensitivity studies, to improve its applicability. The study may contribute theoretically to the literature as follows: First, this thesis isolated four key determinant attributes of supply chain resilience through a comprehensive analysis of existing capabilities. The impact of the four attributes on resilience has been verified with a survey study. Second, the interrelationships of the firms have been expressed using leader-member exchange theory. Through the survey analysis, it was found that leader member exchange affects supply chain resilience significantly. Third, a bicriterion network resilience model using resilience and network value has been proposed, along with an ordering approach. The network representation visualizes not only all the levels of resilience of the firms but also their influences within the network structure. Fourth, a total network resilience (TNR) model is developed, through which one can handle both resilience and interrelations among the firms. The model is applicable to both deterministic and probabilistic cases. Investigating the impact of supply chain capabilities, exchange relationship, and network attributes on supply network resilience offers a fertile avenue for future research. From supply chain perspective, it is recommended that future studies explore the causal relationships among SC capabilities and SC resilience based on different phases of a disruption (i.e., pre-, during-, and post-disruption). One can also investigate the relational behavior based on divergence or crossvergence contexts for more comprehensive analysis. Another possible research direction is to utilize our proposed TNR model in considering triadic relationship and diverse network structural properties. With a further effort on elaboration, we believe that the research results may prove to be a solid basis for network based research in the area of supply chain management.1 INTRODUCTION 1 1.1 General background 1 1.2 Research objectives 3 2 PROBLEM STATEMENTS AND LITERATURE REVIEW 6 2.1 Problem statements 6 2.2 Literature review 7 2.2.1 SC capabilities driven SC resilience management 7 2.2.2 Network perspective integrated SC resilience management 8 2.2.3 Exchange relationship based comprehensive network resilience view 10 2.3 Research assumptions, terminologies, and notations 11 2.3.1 Assumptions 11 2.3.2 Terminologies 12 2.3.3 Mathematical notations 14 3 EXCHANGE RELATIONSHIP, SC CAPABILITIES AND RESILIENCE 15 3.1 Theoretical background and conceptual model 15 3.1.1 SC resilience and competitive advantage 15 3.1.2 SC capabilities related to SC resilience 17 3.1.3 Leader-Member exchange theory based SC management 21 3.2 Research design and methodologies 22 3.2.1 Study 1 – Interpretive structural modeling 22 3.2.2 Study 2 – Hypothesis development 30 3.3 Results and analyses 32 3.3.1 Survey design and data characteristics 32 3.3.2 Model reliability and validity 33 3.3.3 Structural effects 34 3.4 Discussion 35 3.4.1 Five partition levels of SC capabilities 35 3.4.2 Insignificant role of flexibility and agility 35 3.4.3 Significance role of LMX on SC capabilities 36 3.5 Conclusions, implications, and limitations 37 4 BICRITERION NETWORK RESILIENCE MODEL 39 4.1 Literature review 39 4.1.1 SC resilience from the perspective of networks 39 4.1.2 SC resilience studies by disruption phases 43 4.1.3 Social network theory based studies on network typologies 44 4.2 Methodology 45 4.2.1 SC resilience capabilities 46 4.2.2 Operationalization of resilience attributes 48 4.2.3 Operationalization of network attributes 49 4.3 Bicriterion network resilience (BNR) representation 50 4.3.1 Network representation (illustration) 50 4.3.2 Prioritization method: Concordance-discordance approach 52 4.4 A case example 56 4.4.1 Prioritization assessment 58 4.4.2 Interpretation 62 4.5 Conclusions, implications, and limitations 64 5 TOTAL NETWORK RESILIENCE MODEL 66 5.1 Literature review 66 5.1.1 Leader-member exchange theory and exchange relation theory 66 5.1.2 Relational studies in SN context 69 5.2 Development of total network resilience (TNR) model 72 5.2.1 Incorporation of SLMX into a network perspective 72 5.2.2 The Structure of Total Network Resilience Model 74 5.3 The TNR model – A probabilistic model 77 5.3.1 Conceptual framework 77 5.3.2 A TNR probabilistic model - An illustration case 78 5.3.3 Sensitivity analysis - SLMX 82 5.3.4 Sensitivity analysis - Network 88 5.4 Discussion 91 5.4.1 Bayesian modeling based approach 91 5.4.2 Critical path based approach 94 5.5 Conclusion, implication and limitations 98 6 CONLCLUSION 101 6.1 Theoretical implications 101 6.2 Managerial implications 102 6.3 Research limitation and future research 103 REFERENCES 107 APPENDIX 120 ABSTRACT IN KOREAN 122Docto

Online decision problems with large strategy sets

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2005.Includes bibliographical references (p. 165-171).In an online decision problem, an algorithm performs a sequence of trials, each of which involves selecting one element from a fixed set of alternatives (the "strategy set") whose costs vary over time. After T trials, the combined cost of the algorithm's choices is compared with that of the single strategy whose combined cost is minimum. Their difference is called regret, and one seeks algorithms which are efficient in that their regret is sublinear in T and polynomial in the problem size. We study an important class of online decision problems called generalized multi- armed bandit problems. In the past such problems have found applications in areas as diverse as statistics, computer science, economic theory, and medical decision-making. Most existing algorithms were efficient only in the case of a small (i.e. polynomial- sized) strategy set. We extend the theory by supplying non-trivial algorithms and lower bounds for cases in which the strategy set is much larger (exponential or infinite) and the cost function class is structured, e.g. by constraining the cost functions to be linear or convex. As applications, we consider adaptive routing in networks, adaptive pricing in electronic markets, and collaborative decision-making by untrusting peers in a dynamic environment.by Robert David Kleinberg.Ph.D

Geometric-based Optimization Algorithms for Cable Routing and Branching in Cluttered Environments

The need for designing lighter and more compact systems often leaves limited space for planning routes for the connectors that enable interactions among the system’s components. Finding optimal routes for these connectors in a densely populated environment left behind at the detail design stage has been a challenging problem for decades. A variety of deterministic as well as heuristic methods has been developed to address different instances of this problem. While the focus of the deterministic methods is primarily on the optimality of the final solution, the heuristics offer acceptable solutions, especially for such problems, in a reasonable amount of time without guaranteeing to find optimal solutions. This study is an attempt to furthering the efforts in deterministic optimization methods to tackle the routing problem in two and three dimensions by focusing on the optimality of final solutions. The objective of this research is twofold. First, a mathematical framework is proposed for the optimization of the layout of wiring connectors in planar cluttered environments. The problem looks at finding the optimal tree network that spans multiple components to be connected with the aim of minimizing the overall length of the connectors while maximizing their common length (for maintainability and traceability of connectors). The optimization problem is formulated as a bi-objective problem and two solution methods are proposed: (1) to solve for the optimal locations of a known number of breakouts (where the connectors branch out) using mixed-binary optimization and visibility notion and (2) to find the minimum length tree that spans multiple components of the system and generates the optimal layout using the previously-developed convex hull based routing. The computational performance of these methods in solving a variety of problems is further evaluated. Second, the problem of finding the shortest route connecting two given nodes in a 3D cluttered environment is considered and addressed through deterministically generating a graphical representation of the collision-free space and searching for the shortest path on the found graph. The method is tested on sample workspaces with scattered convex polyhedra and its computational performance is evaluated. The work demonstrates the NP-hardness aspect of the problem which becomes quickly intractable as added components or increase in facets are considered

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

LIPIcs, Volume 274, ESA 2023, Complete Volume

LIPIcs, Volume 274, ESA 2023, Complete Volum