Warehouses deliver labor-intensive services to customers. Underperformance may result in high costs and unsatisfied customer demand. New market developments force warehouses to handle a large number of orders within tight time windows. To cope with this, order picking operations need to be optimized by solving a wide range of planning problems. Optimizing order picking planning problems sequentially may yield a suboptimal overall warehouse performance. Still, previous warehouse planning reviews focus on individual planning problems. This literature review differs by investigating combinations of multiple order picking planning problems. A state-of-the-art review and classification of the scientific literature investigating combinations of tactical and operational order picking planning problems in picker-to-parts systems is presented with the aim of determining how planning problems are related. Furthermore, this literature review aims to find excellent policy combinations and to provide guidelines how warehouse managers can benefit from combining planning problems, in order to design efficient order picking systems and improve customer service. Combining multiple order picking planning problems results in substantial efficiency benefits, which are required to face new market developments.
Intermodal freight transport has received increased attention due to problems of road congestion, environmental concerns and traffic safety. A growing recognition of the strategic importance of speed and agility in the supply chain is forcing firms to reconsider traditional logistic services. As a consequence, research interest in intermodal freight transportation problems is growing. This paper provides an overview of planning decisions in intermodal freight transport and solution methods proposed in the scientific literature. Planning problems are classified according to the type of decision maker and decision level. General conclusions are given and subjects for further research are identified.
Distributors are faced with loading constraints in their route planning, e.g.,multi-dimensional packing constraints, unloading sequence constraints, stability constraints and axle weight limits. Ignoring these constraints impairs planning and induces last-minute changes resulting in additional costs. Developing vehicle routing models incorporating loading constraints is critical to more efficient route planning. The last couple of years has seen a huge increase of contributions to this field of research with almost 60 % of these being published after 2009. Our contribution is twofold. First, we overview the recent developments in the literature on all vehicle types in which loading constraints play a key role (trucks, airplanes, ships, and automated guided vehicles), using a state-of-the-art classification scheme to identify the loading constraints considered in each article. Second, we identify research gaps and opportunities for future research.
Dial-a-ride problems consist of designing vehicle routes and time schedules in a system of demand-dependent, collective people transportation. In the standard problem, operational costs are minimized, subject to full demand satisfaction and service level requirements. However, to enhance the practical applicability of solution methods, authors increasingly focus on problem variants that adopt additional real-life characteristics. First, this work introduces an up-to-date classification that distinguishes multiple categories of real-life characteristics. Second, the wide range of solution methods proposed in the literature is reviewed in a structured manner. Although the existing literature is reviewed exhaustively, specific attention is devoted to recent developments. Third, an extensive overview table provides full details on all problem characteristics and solution methods applied in each paper discussed. Fourth, lacunae in research conducted to date and opportunities for future work are identified. Keywords dial-a-ride • demand-responsive transportation • patient transportation • rich vehicle routing • real-life characteristics • literature review
This paper identifies research opportunities which will enable the further integration of inland waterway transport in the intermodal supply chain. Intermodal transport may be interpreted as a chain of actors who supply a transport service. Inland navigation can play a crucial role in increasing supply chain service performance. A first group of research challenges lies in the evolving relationship between transport geography and logistics activities. The next set of research challenges has the objective to encourage efficient operations in IWT: development of a system wide model for IWT, integration of operational planning systems and analysis of bundling networks. A third group of research efforts is directed towards shippers and consignees who use the intermodal transport chain to send or receive their goods: further development of models that integrate intermodal transport decisions with supply chain decisions and creation of green supply chains. A fourth cluster of research challenges concerns the problem domain of external cost calculations. Finally detailed time series data on freight transport should be collected to support these future research tracks.
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