A Comprehensive Approach to Account for Weather Uncertainties in Ship Route Optimization (original) (raw)
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Since sailing along the Northern Sea Route (NSR) through the Arctic Ocean comes into reality, commercial shipping developments including opening new liner services along this route have been put on the agenda. However, uncertainties within weather and ocean conditions in this region, especially during temperature-varying seasons, may cause failure to on-time arrivals, resulting unignorable or even unaffordable monetary losses. As a result, these uncertainties will inevitably affect cargo shippers’ willingness of choosing this being-explored route, even if on average its shipping time is much shorter than that of the traditional Asia-Europe shipping lines. In this context, the present paper describes a liner ship routing and scheduling problem considering schedule-sensitive demand and late-arrival penalty for operating incoming NSR shipping lines in the future. By using two types of uncertainty sets, bounded and budget-bounded uncertainty sets, we construct and solve two robust counterparts of this problem. The deterministic model and bounded robust model can be seen as special cases of the budget-bounded robust model when the uncertainty budget is set to null and full, respectively. A multifaceted case study of planning liner shipping routes and schedules along the NSR is conducted to validate the efficacy and efficiency of the proposed models and identify the effects of uncertainty bounds and budgets on the solution performance. The following facts and conclusions are revealed from the optimization results of the case study: The budget-bounded robust model functions the best in the worst condition; low revenue rate and high demand sensitivity are the major factors for excluding a candidate port from the route; the order of a visited port in the route decides the weight of its uncertainty budget on the entire shipping line; setting the uncertainty budget in a decelerative way will enhance the scheduling robustness of solutions.
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Weather routing methods are essential for planning routes for commercial shipping and recreational craft. This paper provides a methodology for quantifying the significance of numerical error and performance model uncertainty on the predictions returned from a weather routing algorithm. The numerical error of the routing algorithm is estimated by solving the optimum path over different discretizations of the environment. The uncertainty associated with the performance model is linearly varied in order to quantify its significance. The methodology is applied to a sailing craft routing problem: the prediction of the voyaging time for an ethnographic voyaging canoe across long distance voyages in Polynesia. We find that the average numerical error is 0.396%, corresponding to 1.05 hours for an average voyage length of 266.40 hours. An uncertainty level of 2.5% in the performance model is seen to correspond to a standard deviation of ±2.41 − 3.08% of the voyaging time. These results illustrate the significance of considering the influence of numerical error and performance uncertainty when performing a weather routing study.
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A Study on the Use of Ensemble Weather Forecasts for Ship's Weather Routeing
The Journal of Japan Institute of Navigation
When planning a transoceanic voyage, ships weather routeing is a valuable tool, which using an optimization rnethod can help achieve different objectives. The accuracy of the generated optimized route depends on a large degree on the range and accuracy of the fbrecasted weather data that is necessaiy to describe the evolution of the weather conditions througheut the voyage. With the developinent of the ensemblc prediction system, a new source ofweather infbrmation fbr relatively longer times became available. In this study, the usability ofthe one month wind ensernble issued by the Japan meteorological agency is investigated. Simulations were canied fbr three transoceanic routes that take over 16 days, using various weather inputs; traditional routeing methods are compared with the use ofthe ensemble mean and its combination with the traditional deterministic forecast and both methods are scored against the mest optimal route obtained by the use of the forecast analysis. Results show that the use ofthe mean of the ensemble forecast may he]p achieve voyage times closer to the opthnal ones, and the spread of the routes generated by using ditferent weather inputs can give an idea about the certajnty of th ¢ obtained route, Ke:p,wortts: ShiplsweatheFrouteing, which are due to the sensitive dependence on the initial conditions (initial errors) and modeling errors. In an eflbrt to have a better grasp ofthe fbrecast errors and in ordeT to increase the range
Ship weather routing based on seakeeping performance
Ship weather routing is the process to efficiently avoid undesired sailing conditions, especially due to bad weather. Issues at stake are not only the ship’s and cargo’s safety, but also crew comfort. Some major factors to be considered in this process are: the minimum route distance between ports, the predicted sea state for the sailing period and the ships seakeeping performance. This paper presents a geographic infor-mation system (GIS) that determines the best sailing route, based on multicriteria raster grid analysis. The system is fed with data from a wave forecast model applied to the North Atlantic and calculates the ships per-formance for different wave significant height, period and relative wave direction to the ship’s route. Ship’s seakeeping performance in based on the roll, pitch and heave responses. A case study is presented for a voy-age between Lisbon and New York, during the month of November 2006, for a container ship sailing at 22 kts. The processing result is a geospatial cost-travelling matrix that is used to calculate the accumulated cost to sail to New York. Based on this matrix, the least cost path is then calculated and presented.
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Ship routing process taking into account weather conditions is a constrained multi-objective optimization problem and it should consider various optimization criteria and constraints. Formulation of a stability-related, dynamic route optimization constraint is presented in this paper. One of the key objectives of a cross ocean sailing is finding a compromise between ship safety and economics of operation. This compromise should be taken into account by the planning procedure and proper optimization algorithm. In this research complex stabilityrelated phenomena are adopted as the basis for the constraint set formulation in weather routing. Thus, the synchronous roll, parametric resonance, surf riding and broaching-to are considered according to the IMO MSC.1/ Circ.1228 guidance. However, the dangerous resonance motion of the ship depends on her natural period of roll and a degree of tuning to the encounter wave period. This natural period strictly depends on the GZ curve shape and, consequently, on the amplitude of roll. In order to properly model the natural period of roll, a new method utilizing equivalent metacentric height is applied and incorporated into the route optimization. Sample calculations of the cross ocean routes are presented and the effect of the dynamic approach to the constraint set is demonstrated and discussed.
Optimizing maritime travel time reliability
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Travel time reliability optimization problems generally cannot be formulated in direct mathematical form due to complexity of precise information. Classically, qualitative form of objective function and/or constraints does not allow the decision maker to represent it in a typical form of standard optimization model. This article attempts to resolve travel time reliability optimization problem of maritime transportation. The marine vessel’s travel time consists of seven time components. The travel time reliability is considered in a possibilistic manner, and then the reliability optimization problem with budgetary constraints and stage-time limitations is formulated. Next, algorithmic framework for solution of the possibilistic programming has been proposed, followed by a suitable illustration. Finally, this article investigates the parameter sensitivity that has consequences in the marine vessel’s transportation decision making. The proposed programming model is useful in the decisi...
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This study proposes a ship weather-routing algorithm based on the composite influence of multi-dynamic elements for determining the optimized ship routes. The three-dimensional modified isochrone (3DMI) method utilizing the recursive forward technique and floating grid system for the ship tracks is adopted. The great circle sailing (GCR) is considered as the reference route in the earth coordinate system. Illustrative optimized ship routes on the North Pacific Ocean have been determined and presented based on the realistic constraints, such as the presence of land boundaries, non-navigable sea, seaway influences, roll response as well as ship speed loss. The proposed calculation method is effective for optimizing results by adjusting the weighting factors in the objective functions. The merits of the proposed method can be summarized as: (1) the navigability of the route can be analyzed dynamically to acquire the optimal route; (2) adopting multidynamic elements as weighting factors has the benefits in energy efficiency, time-saving and minimum voyage distance; and (3) an ability to enhance speed performance and to incorporate safety concern in a dynamic environment.