On Dynamical Situations in Vehicle Routing Problems (DSVRP)
Felix Makanjuola Aderibigbe,
Kayode James Adebayo
Issue:
Volume 6, Issue 1, January 2021
Pages:
1-9
Received:
12 January 2020
Accepted:
21 January 2020
Published:
12 January 2021
Abstract: This paper discusses the formulation of a stochastic Vehicle Routing Problem (VRP) process, introduced to existing deterministic VRP process, directing all efforts towards the dynamical situations that occur in a typical VRP setting as it applies to everyday real-life situations. It contrasts the dichotomy between static and dynamical situations in VRP, constructs and analyzes the relationship between static and dynamical situations in Vehicle Routing Problems, formulates an expression to describe the dynamical situation in VRP and relates the problem formulation to existing VRP with a view to solving the problem as it applies to real-life situations, a major trend in the business world today. With a view to achieving these, this paper associates the merits of reactivation of route, re-optimization of operation process and projects an anticipatory demand for a dynamical situation in VRP with stochastic requests via three stages: Pre-Decision States, Decisions States and Post-Decision States. First, as a reaction to anticipatory customers’ requests, the current routing plans need to be re-optimized and current customers’ request reactivated. Second, potential future requests need to be anticipated along current decision making since life itself is dynamic. Decisions need to be made in good time. Though, the limited time frame between when a vehicle leaves and returns to the depot often prohibits extensive optimization in both dimensions rather, answer the questions that arise on how to utilize the limited time effectively and judiciously, satisfying both the current and anticipatory customers equally.
Abstract: This paper discusses the formulation of a stochastic Vehicle Routing Problem (VRP) process, introduced to existing deterministic VRP process, directing all efforts towards the dynamical situations that occur in a typical VRP setting as it applies to everyday real-life situations. It contrasts the dichotomy between static and dynamical situations in...
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Ship Berthing Safety Assessment Based on Ship-Handling Simulator
Geng Hejun,
Fan Fuquan,
Jiang Xiaobin,
Wang Deling,
Tao Qingfeng
Issue:
Volume 6, Issue 1, January 2021
Pages:
10-21
Received:
6 February 2021
Accepted:
17 February 2021
Published:
26 February 2021
Abstract: As the development of ship building technologies, ships have been becoming larger and larger. As a result, the existing ports and waterways can not meet the requirements of safe navigation, berthing and unberthing operations of large ships. In order to ensure the safe berthing and unberthing for large ships, wharf and waterways need to be rebuilt, also it is necessary to check whether the rebuilt wharf can meet the navigation needs. In this paper, the ship handling simulator is used to simulate the safe berthing and unberthing of the pier. This paper establishes the mathematical model of ship motions, generates virtual navigation environment, applies the concepts of track zone width, potential ship handling water area, utility function and risk of berthing operation, and makes a comprehensive analysis of the width of the channel, ship manoeuvring waters and the safety of berthing operation, and puts forward some objective and reasonable suggestions on the safety of berthing. By practical application of ship-handling simulator to evaluate the safety of ship berthing and unberthing, it shows that the method based on ship-handling simulator is objective, feasible and reasonable to analyze and evaluate the navigation safety of wharf engineering, and has a good value of application.
Abstract: As the development of ship building technologies, ships have been becoming larger and larger. As a result, the existing ports and waterways can not meet the requirements of safe navigation, berthing and unberthing operations of large ships. In order to ensure the safe berthing and unberthing for large ships, wharf and waterways need to be rebuilt, ...
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Study on Offloading Operation of Cylindrical FPSO Under Extreme Weather
Hejun Geng,
Jiawei Lu,
Deling Wang,
Jie Wang
Issue:
Volume 6, Issue 1, January 2021
Pages:
22-33
Received:
5 March 2021
Accepted:
17 March 2021
Published:
26 March 2021
Abstract: With the wide application of cylindrical FPSO (Floating Production Storage and Offloading, FPSO), more and more people pay attention to its operational safety. To study and explore the safety of cylindrical FPSO offloading operation under extreme weather, it is necessary to conduct the simulation of whole operation process in such conditions. At first, the programming models are formulated for the cylindrical FPSO, shuttle tanker and tugs; then, based on the modelling, the responses of the cylindrical FPSO are simulated during offloading operation under various conditions, combined with Delphin Method and relevant theory. The most unfavorable load state and ultimate wind speed on unfavorable wind direction are explored through three stages: 1. changing the loading status of shuttle tanker and cylindrical FPSO; 2. changing the relative bearing of wind; 3. changing the wind speed. The results showed that when the offloading state is FPSO half-load & tanker half-load, it is the worst state to control the offloading system and the limit wind speed in the simulation is: cross wind ≤20 knots.By analyzing the motion response of cylindrical FPSO which is assisted by two tugs, a relatively objective and reasonable solution is obtained, which provides a beneficial reference for the future cylindrical FPSO offloading operation under the extreme weather conditions.
Abstract: With the wide application of cylindrical FPSO (Floating Production Storage and Offloading, FPSO), more and more people pay attention to its operational safety. To study and explore the safety of cylindrical FPSO offloading operation under extreme weather, it is necessary to conduct the simulation of whole operation process in such conditions. At fi...
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