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| 2. |
- Wang, Kai, et al.
(författare)
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Cruise service planning considering berth availability and decreasing marginal profit
- 2017
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Ingår i: Transportation Research Part B: Methodological. - : Elsevier BV. - 0191-2615. ; 95, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses a decision problem on planning cruise services for a cruise ship so as to maximize the total profit during a planning horizon. The service is a sequence of ports (harbor cities) that the cruise ship visits. In this decision problem, the constraint about the availability of berths at each port is taken into account. In reality, if a cruise service is executed by the ship repeatedly for several times, the profit earned by the cruise service in each time decreases gradually. This effect of decreasing marginal profit is also considered in this study. We propose a nonlinear integer programming model to cater to the concavity of the function for the profit of operating a cruise service repeatedly. To solve the nonlinear model, two linearization methods are developed, one of which takes advantage of the concavity for a tailored linearization. Some properties of the problem are also investigated and proved by using the dynamic programming (DP) and two commonly used heuristics. In particular, we prove that if there is only one candidate cruise service, a greedy algorithm can derive the optimal solution. Numerical experiments are conducted to validate the effectiveness of the proposed models and the efficiency of the proposed linearization methods. In case some parameters needed by the model are estimated inexactly, the proposed decision model demonstrates its robustness and can still obtain a near-optimal plan, which is verified by experiments based on extensive real cases.
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| 3. |
- Wang, Kai, et al.
(författare)
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Ship type decision considering empty container repositioning and foldable containers
- 2017
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Ingår i: Transportation Research Part E: Logistics and Transportation Review. - : Elsevier BV. - 1366-5545. ; 108, s. 97-121
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses a problem of ship type decision considering empty container repositioning and foldable containers, which determines the capacity of ships deployed in a given shipping route at a tactical level and empty container repositioning between ports at an operational level. It considers the use of foldable containers and aims to find under what conditions, a shipping liner needs to use the foldable containers. To solve the problem, we formulate a network flow model with a revised network simplex algorithm, based on which an exact solution approach is designed to determine the optimal ship type.
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| 4. |
- Wang, Shuaian, et al.
(författare)
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Cruise itinerary schedule design
- 2017
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Ingår i: IISE Transactions. - : Informa UK Limited. - 2472-5862 .- 2472-5854. ; 49:6, s. 622-641
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Tidskriftsartikel (refereegranskat)abstract
- The Cruise Itinerary Schedule Design (CISD) problem determines the optimal sequence of a given set of ports of call (a port of call is an intermediate stop in a cruise itinerary) and the arrival and departure times at each port of call in order to maximize the monetary value of the utility at ports of call minus the fuel cost. To solve this problem, in view of the practical observations that most cruise itineraries do not have many ports of call, we first enumerate all sequences of ports of call and then optimize the arrival and departure times at each port of call by developing a dynamic programming approach. To improve the computational efficiency,we propose effective bounds on the monetary value of each sequence of ports of call, eliminating non-optimal sequences without invoking the dynamic programming algorithm. Extensive computational experiments are conducted and the results showthat, first, using the bounds on the profit of each sequence of ports of call considerably improves the computational efficiency; second, the total profit of the cruise itinerary is sensitive to the fuel price and hence an accurate estimation of the fuel price is highly desirable; third, the optimal sequence of ports of call is not necessarily the sequencewith the shortest voyage distance, especially when the ports do not have a natural geographic sequence.
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| 5. |
- Wang, Tingsong, et al.
(författare)
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A two-stage stochastic nonlinear integer-programming model for slot allocation of a liner container shipping service
- 2021
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Ingår i: Transportation Research Part B: Methodological. - : Elsevier BV. - 0191-2615. ; 150, s. 143-160
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we propose a container slot allocation problem for a liner shipping service. A liner containership provides a regular shipping service with a fixed itinerary and schedule. In practice, the liner containership may not be fully loaded, which results in a loss of revenue. We therefore segment shippers into two classes: contract shippers and spot shippers. A contract shipper has a contract with the shipping company and negotiates a fixed minimum quantity, so that the shipping company can secure a steady revenue. The remaining containership slots are open to spot shippers, allowing the shipping company to obtain ad hoc revenue. The container slot allocation problem is investigated in this study using a two-stage stochastic mixed-integer nonlinear programming model. We use the sample average approximation based on Lagrangian relaxation and dual decomposition techniques to effectively solve the model. Finally, we conduct a case study to evaluate the applicability and effectiveness of the proposed model and the solution algorithm.
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| 6. |
- Wang, Wei, et al.
(författare)
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Emergency facility location problems in logistics: Status and perspectives
- 2021
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Ingår i: Transportation Research Part E: Logistics and Transportation Review. - : Elsevier BV. - 1366-5545. ; 154
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Tidskriftsartikel (refereegranskat)abstract
- Emergencies that pose potential threats to our health, life, and properties can happen anywhere and anytime and may result in huge losses if they are not handled timely and effectively. An immediate response to emergencies is the key to mitigate these threats and losses. As the response time is largely dependent on the number and location of emergency facilities, the problem of how to determine the optimal number of emergency facilities and their best locations is of great strategic importance and of great interest to researchers. One of the most common approaches for researchers to address the emergency facility location problem is to model it as a discrete coverage-based emergency facility location problem. This paper provides a comprehensive overview of this problem, including mathematical models and their extensions and applications. In addition, the commonly used solution methods and some promising future research questions based on covering models are discussed.
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| 9. |
- Chen, Jingxu, et al.
(författare)
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A modelling framework of drone deployment for monitoring air pollution from ships
- 2019
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Ingår i: Smart Innovation, Systems and Technologies. - Cham : Springer International Publishing. - 2190-3026 .- 2190-3018. ; 98, s. 281-288
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Konferensbidrag (refereegranskat)abstract
- Sulphur oxide (SOx) emissions impose a serious health threat to the residents and a substantial cost to the local environment. In many countries and regions, ocean-going vessels are mandated to use low-sulphur fuel when docking at emission control areas. Recently, drones have been identified as an efficient way to detect non-compliance of ships, as they offer the advantage of covering a wide range of surveillance areas. To date, the managerial perspective of the deployment of a fleet of drones to inspect air pollution from ships has not been addressed yet. In this paper, we propose a modelling framework of drone deployment. It contains three components: drone scheduling at the operational level, drone assignment at the tactical level and drone base station location at the strategic level.
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| 10. |
- Li, Miao, et al.
(författare)
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Unmanned aerial vehicle scheduling problem for traffic monitoring
- 2018
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Ingår i: Computers and Industrial Engineering. - : Elsevier BV. - 0360-8352. ; 122, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- For more accurate multiple-period real-time monitoring of road traffic, this paper investigates the unmanned aerial vehicle scheduling problem with uncertain demands. A mixed integer programming model is designed for this problem by combining the capacitated arc routing problem with the inventory routing problem. A local branching based solution method is developed to solve the model. A case study which applies this model to the road traffic in Shanghai is performed. In addition, numerical experiments are conducted to validate the effectiveness of the proposed model and the efficiency of the proposed solution method.
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