781 research outputs found

    Combined ship routing and inventory management in the salmon farming industry

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    We consider a maritime inventory routing problem for Norway's largest salmon farmer both producing the feed at a production factory and being responsible for fish farms located along the Norwegian coast. The company has bought two new ships to transport the feed from the factory to the fish farms and is responsible for the routing and scheduling of the ships. In addition, the company has to ensure that the feed at the production factory as well as at the fish farms is within the inventory limits. A mathematical model of the problem is presented, and this model is reformulated to improve the efficiency of the branch-and-bound algorithm and tightened with valid inequalities. To derive good solutions quickly, several practical aspects of the problem are utilized and two matheuristics developed. Computational results are reported for instances based on the real problem of the salmon farmer

    Reallocation of seafood freight flows from road to sea

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    Confidential until 24-may-201

    Downstream logistics optimization at EWOS Norway

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    The Norwegian company EWOS AS produces fish feed for the salmon farming industry, supplying approximately 300 customers spread along the coast of Norway. The feed is produced at three factory locations and distributed by a fleet of 10 dedicated vessels. The high seasonality of the demand and the large number of customers make the distribution planning a substantial challenge. EWOS handles it by operating a system of mostly fixed routes with decentralized planning at each factory. The distribution can be described as a multi-depot vehicle routing problem with time windows, multiple vehicle usage, inter-depot routes, heterogeneous fleet and a rolling horizon. The paper presents a mathematical model for this problem, which is solved by heuristics and meta heuristics. Based on detailed historical data collected by EWOS during the autumn of 2010, the model has proposed a dynamic set of routes with a significant reduction of travelled distance - close to 30% - and an increase of average vessel fill-rate - from 60% up to 95%. This implies a substantial fuel saving, with a positive environmental impact, and also a potential for downscaling the fleet, with additional considerable cost savings for the company.publishedVersio

    Identification of Outer Continental Shelf Renewable Energy Space-Use Conflicts and Analysis of Potential Mitigation Measures

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    The ocean accommodates a wide variety of uses that are separated by time of day, season, location, and zones. Conflict can and does occur, however, when two or more groups wish to use the same space at the same time in an exclusive manner. The potential for conflict is well known and the management of ocean space and resources has been, and is being, addressed by a number of State, regional, and Federal organizations, including, among others, coastal zone management agencies, state task forces, and regional fisheries management councils. However, with new and emerging uses of the ocean, such as aquaculture and offshore renewable energy, comes the potential for new types of space-use conflicts in ocean waters. In recent years, the Bureau of Ocean Energy Management (BOEM) (formerly the Minerals Management Service [MMS]) has examined ocean space-use conflicts and mitigation strategies in the context of offshore oil and gas exploration and production and sand and gravel dredging, activities that are both subject to BOEM regulation and oversight. BOEM now has authority to issue leases on the Outer Continental Shelf (OCS) for renewable energy projects, but seeks additional information on potential conflicts between existing uses of the ocean environment and this new form of activity. The broad purpose of this study was to begin to fill this gap by (1) identifying potential spaceuse conflicts between OCS renewable energy development and other uses of the ocean environment, and (2) recommending measures that BOEM can implement in order to promote avoidance or mitigation of such conflicts, thereby facilitating responsible and efficient development of OCS renewable energy resources. The result is a document intended to serve as a desktop resource that BOEM can use to inform its decision making as the agency carries out its statutory and regulatory responsibilities

    Lagrangian relaxation bounds for a production-inventory-routing problem

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    We consider a single item Production-Inventory-Routing problem with a single producer/supplier and multiple retailers. Inventory management constraints are considered both at the producer and at the retailers, following a vendor managed inventory approach, where the supplier monitors the inventory at retailers and decides on the replenishment policy for each retailer. We assume a constant production capacity. Based on the mathematical formulation we discuss a classical Lagrangian relaxation which allows to decompose the problem into four subproblems, and a new Lagrangian decomposition which decomposes the problem into just a production-inventory subproblem and a routing subproblem. The new decomposition is enhanced with valid inequalities. A computational study is reported to compare the bounds from the two approaches

    Modelling a cyclic maritime inventory routing problem

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    Applications of Satellite Earth Observations section - NEODAAS: Providing satellite data for efficient research

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    The NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS) provides a central point of Earth Observation (EO) satellite data access and expertise for UK researchers. The service is tailored to individual users’ requirements to ensure that researchers can focus effort on their science, rather than struggling with correct use of unfamiliar satellite data

    Satellite monitoring of harmful algal blooms (HABs) to protect the aquaculture industry

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    Harmful algal blooms (HABs) can cause sudden and considerable losses to fish farms, for example 500,000 salmon during one bloom in Shetland, and also present a threat to human health. Early warning allows the industry to take protective measures. PML's satellite monitoring of HABs is now funded by the Scottish aquaculture industry. The service involves processing EO ocean colour data from NASA and ESA in near-real time, and applying novel techniques for discriminating certain harmful blooms from harmless algae. Within the AQUA-USERS project we are extending this capability to further HAB species within several European countries

    Report on findings on transportation and logistics of selected food value chains:Salmon to fillet case study

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    • Transportation has significant impact on food costs and the environment. It is a major contributor to carbon emissions, accounting for almost a quarter of the CO2 emissions in the EU, of which 30% is attributed to the food sector. • This deliverable addresses the modelling of food chains’ transportation and logistics. It develops a robust model for policy support, which is applied to a specific case as a worked example. The approach can be used to model the transport and logistics of other food supply chains, given data availability. • The mathematical modelling aims to optimise the cost and effectiveness of logistics operations. It also allows for the integration and consideration of environmental aspects within transportation, processing and distribution operations. • Specifically, the deliverable focuses on the development of a logistics mathematical model using Atlantic salmon as an exemplary example of a globally integrated food supply chain. A Norwegian salmon exporter was engaged to supply data for validating the mathematical model. • The model follows a multi-objective optimization approach that captures the trade-off between total logistics cost and the environment. It has two objectives. Firstly, to minimize total costs associated with transportation, fuel consumption, inventory holding, processing and residuals/waste. Secondly, to reduce CO2 emissions incurred by production at plants, transportation from suppliers to plants, and transportation from plants to customers. • Constraints related to supply, processing capacity, storage capacity, demand, carbon emissions, inventory balancing, transportation capacity, and different modes of transportation between different types of plants and facilities are also consider within the model. • Model development, validation and policy recommendation occurred in four stages: (i) mapping supply chain linkages and product flows, (ii) designing the mathematical model, (iii) data collection for parameters of the model and (iv) model validation and deriving policy recommendation. • Before modeling, consultation with salmon supply chain actors occurred as a first step to map the supply chain linkages. This involved expert interviews with VALUMICS partners. • Based on the mapping of the supply chain, a mathematical model was developed. However, given the complexity of the supply chain and the limited information that can be drawn from a single company which completely covers both the supply and the demand ends of the value chains, the model was divided into two stages (Model N1 and N2) • First it optimises the supply chain network from salmon farms, abattoirs, primary processing plants, secondary processing plants and wholesalers so to meet the demand of the Secondary Processing Plants and Wholesalers for Fresh HOG (Head-on-Gutted) product (Model N1) (farm to wholesaler). • Second, it addresses the supply chain from the secondary processing plants and wholesalers to retailers. The secondary processing plants process HOG into whole fillet, salmon by-products and some residual amount so to meet the demand of retailers (Model N2) (wholesaler to retailer). • An additional model (Model M) allows for the optimisation of the overall supply chain network where, for example, a Company X tries to meet the demand of retailers in different time periods (farm to retailer). • A transportation scenario analysis was also conducted by considering options for various maritime transportation routes from primary processing plant to secondary processing and primary processing plant to various wholesalers. • The results from the three models highlight that it is essential for any company to optimise the overall supply chain network system (from salmon farms to retailers), as the total cost for model M is relatively much lower than the combined total cost of N1 and N2. • Each model also shows that the supply chain network is sensitive to fuel cost and consequently, fuel consumption and distances between actors across the supply chain. • Environmental impact is generally measured by fuel consumption during operations and in the case of food chain, transportation and distribution are important contributors via the use of fuel-based vehicles, sea vessels and/or airplanes. • The scenarios analysis highlights the importance of adopting maritime transportation routes in terms of significantly reducing the total cost, fuel cost and overall carbon emission. Hence shifting certain logistics operations from road to maritime transportation from the perspective of economic and environmental benefits are advocated. • For short to medium distances (vans, trucks, rails and sea vessels) that covers transportation trips to reach airport hubs and big cities, lowering CO2 emissions depends on the emissions ratio (the relative emissions impact of delivery vehicle when compared to personal vehicle – mostly applied in urban logistics) and customer density. • For long distance transport (air), environmental improvement can be mainly achieved through technological development and this has been well supported by research dedicated specifically to address EU aviation industry challenges. • The models are developed for a planning horizon consisting of discrete time periods, aiding the possibility of studying demand and supply uncertainty and its consequences in supply chain decision making. Hence, they help decision makers to identify the changes in a supply chain network when different transportation routes are adopted (for example whether maritime routes can be adopted or not in place of road/rail transportation, to address environmental concerns related to fuel consumption and carbon emissions). • The models are valuable for policy makers in terms of understanding the costs and emissions associated with different food supply chains, as well as the effects of particular policy interventions and market developments (e.g. variation in demand, fuel costs, emission and waste constraints). • They can aid supply chain managers to make decisions regarding the amountof inventory to be kept in different time periods.Aditjandra, P., De, A., M., Gorton, M., Hubbard, C., Pang, G., Mehta, S., Thakur, M., Richardson, M., Bogasson, S., Olafsdottir, G. (2019) Report on findings on transportation and logistics of selected food value chains. VALUMICS "Understanding Food Value Chains and Network Dynamics", funded by European Union's Horizon 2020 research and innovation programme GA No 727243. Deliverable: D7.1, Newcastle University, UK, 94 page
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