چکیده:
In this paper modelling maritimeinventory-routing problem for liquefied natural gas (LNG) under uncertainty of travel time is presented. We consider one hypothetical LNG manufacturer in Iran that sells its products in the form of long-term contracts and spots. The purpose of the study is to examine and compare the shipping costs of split and non-split delivery.The objective function is minimizing the operational costs, contract penalties, and spot fees, and the main constraints are liquefaction port constraints, ship flows, customer and contractual constraints. Considering uncertainty in the problem is one of this paper's contributions which is modeled by assuming vessels speed as a fuzzy parameter. The parameter and related constraints are defuzifided by Jimenez approach and for solving this problem a metaheuristic method is applied and effectiveness of results are compared with a commercial solver. According to the computational results split delivery policy in deterministic problem is cost effective but in the uncertain situation it is more costly comparing to non-split delivery policy, so split delivery is not recommended in maritime transportation with uncertain nature.
خلاصه ماشینی:
This paper develops a model for LNG inventory-routing problem in the context of tactical planning under travel time uncertainty and with the approach of reducing operational costs and contractual penalties.
MIRP modelling components [%%ابتدای جدول%%Marine Supply chain; Modeling components supply; Product type (L-bulk, crude oil, LNG,cement,Amonia,etc) Product Number (Single, Multiple) Production rate (Fix, Variable) Storage and Loading; Inventory management (Lot sizing, not lot sizing) Inventory type (Deteriorating,non deteriorating) Transportation & Maintenance; Shipping (Liner, tramp, industrial) Fleet composition (Hetrogenous, Homogenous) Transportation structure (1-1,1-m,m-m-m) Transportation type (Successive, not successive) Maintenance Unloading & Storage; Storage in unloading port(storage considerations in only demand side/on both sides) Port type(offshore) Consumption; Consumption rate(fix,varaible) Contract type(long-term,spot,futures) Delivery(FOB،CIF،DES) %%انتهای جدول%%] (View the image of this page) Figure1.
Al -Khayyal and Hwang (2007) studied and modeled the marine routing problem with inventory constraints for multi-commodity shipments of liquid products.
3. Arc-flow & Path-flow models Christensen (1999) used decomposition method to solve the combined problem of inventory management and routing for ammonia carriers.
Problem parameters T Planning horizon (Time in this model is discrete and day-to-day) (View the image of this page) The first part in the objective function is the total operational cost of sending LNG ships.
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