In transportation of goods in large container ships, shipping industries need to minimize the time spent at ports to load/unload containers. An optimal stowage of containers on board minimizes unnecessary unloading/reloading movements, while satisfying many operational constraints. We address the basic container stowage planning problem (CSPP). Different heuristics and formulations have been proposed for the CSPP, but finding an optimal stowage plan remains an open problem even for small-sized instances. We introduce a novel formulation that decomposes CSPPs into two sets of decision variables: the first defining how single container stacks evolve over time and the second modeling port-dependent constraints. Its linear relaxation is solved through stabilized column generation and with different heuristic and exact pricing algorithms. The lower bound achieved is then used to find an optimal stowage plan by solving a mixed-integer programming model. The proposed solution method outperforms the methods from the literature and can solve to optimality instances with up to 10 ports and 5,000 containers in a few minutes of computing time.
Melting Arctic sea ice, shore ice, and permafrost are changing costs and benefits to transport routes between Atlantic and Pacific oceans, and more generally, for maritime economic activity in the Arctic. We investigate the potential for development of Arctic ports from a logistics (demand) and an infrastructural (supply) point of view that directly incorporates local concerns. This approach broadens the scope of the discussion from existing analyses that focus primarily on the ways in which global forces, exerted through resource extraction or trans-polar shipping, impact the Arctic.
This study analyses the relation between management practices and the performance of Brazilian port authorities. In order to do so, a survey-based evaluation tool of the quality of management practices was developed. In addition, a set of operational and financial performance indicators of such port authorities and their ports was calculated. The differences in operational and financial performance between port authorities with a high and a low quality of management practices were analysed by Student t-tests and the relation between management practices and port performance was accessed through linear regression analysis. The results indicated that the better managerial practices have a positive impact on port authorities' financial performance but have no significant impact on ports' operational performance. The study also found that port authorities controlled by States and Municipalities have better financial and operational results and use more management practices than those managed by the Brazilian Federal Government.
Background: Fishing is a risky occupation as injuries and fatalities in fishing vessels are quite common. This paper investigates the pattern of injuries aboard fishing vessels in Denmark to get a better understanding of areas where further action is needed to reduce the number of injuries and fatalities in Danish fishing vessels. Materials and methods: Data for this study, extracted from the Danish Fishermen’s Occupational Health Service’s database (in the period 1998–2012) and the Danish Maritime Authority’s accident report from 2013 to 2016, include 1840 injuries in Danish fisheries. Result: The results showed decreased injuries in the study period from 45 injuries and deaths per 1000 fishermen reported to the authorities to 12 injuries and deaths per 1000 fishermen in 2016: 2.1% (n = 39) of all reported injuries in the study period resulted in the death of a fisherman and the remaining injuries resulted in sick leave of more than one day; 52.5% (n = 600) of reported injuries involved fishermen who have less than one year’s experience of employment; 29% (n = 407) of injuries took place between 12:00 and 16:00, and the second largest number of injuries, 23.3% (n = 324), took place between 8:00 and 12:00. The incident rate of slip/fall injuries has decreased from 10.06 per 1000 fishermen in 1998 to 3.84 in 2016. The incidence rate of injuries caused by crushing also decreased, from 9.32 accidents per 1000 fishermen in 1998 to 2.56 in 2016. Most of the injuries, 74.5% (n = 1307), happened on the deck of the vessel. Sprain/strain was among the most common injuries (34.2%; n = 538) followed by fracture (24.8%; n = 391). Conclusion: This study indicated that the number of injuries had been gradually decreasing in Danish commercial fishing vessels in the period from 1998 to 2016. The rate of injuries had been declining due to several initiatives such as the establishment of The Danish Fishermen’s Occupational Health Services, training, safety campaigns, technological improvement and structural changes in fisheries management. However, there are still places for improvement.
Fault-tolerance is crucial to maintain safety in offshore operations. The objective of this paper is to show how systematic analysis and design of fault-tolerance is conducted for a complex automation system, exemplified by thruster assisted Position-mooring. Using redundancy as required by classification societies' class notations for offshore position controlled vessels, the paper shows how violations of normal behaviour of main components can be detected and isolated. Using a functional service philosophy, diagnosis procedures are auto-generated based on provable correct graph analysis methods. Functional faults that are only detectable, are rendered isolable through an active isolation approach. Once functional faults are isolated, they are handled by fault accommodation techniques to meet overall control objectives specified by class requirements. The paper illustrates the generic methodology by a system to handle faults in mooring lines, sensors or thrusters. Simulations and model basin experiments are carried out to validate the concept for scenarios with single or multiple faults. The results demonstrate that enhanced availability and safety are obtainable with this design approach. While methods are introduced at a tutorial level, the paper is original by providing a total Position-mooring system design that ensures resilience to any single fault and to selected multiple faults.
The International Council for the Exploration of the Sea (ICES) occupies a central role in the advice system to support the implementation of an ecosystem approach to fisheries management (EAFM) in the European Union (EU). Despite improvements, its capacity to deliver ecosystem advice seems to be far from a fully functional operational framework. To what extent availability of appropriate scientific advice is a barrier for a more widespread use of an EAFM in Europe remains an open question. Building on the findings of a large research project, this article explores what advice ICES can provide. The article concludes that: (i) ICES has taken a leading role in generating an EAFM framework in which management decisions can operate; (ii) the advice “suppliers” and the advice “users” agree on the feasibility of using existing knowledge to “do EAFM now”; (iii) ICES can address a range of shortcomings, but some of the present bottlenecks demand concerted action between the advisory system and the political realm. The implementation of an EAFM requires consistency between science and management. ICES appears as well-suited to facilitate the dialogue on applying an EAFM in the EU, but it is unrealistic to expect ICES to produce all the answers.
We present recent progress on the development of a new fully nonlinear potential flow (FNPF) model for estimation of nonlinear wave-body interactions based on a stabilized unstructured spectral element method (SEM). We introduce new proof-of-concepts for forced nonlinear wave-body interaction in two spatial dimensions to establish the methodology in the SEM setting utilizing dynamically adapted unstructured meshes. The numerical method behind the proposed methodology is described in some detail and numerical experiments on the forced motion of (i) surface piercing and (ii) submerged bodies are presented.
This paper presents the design and development of a conceptual prototype of an autonomous self-driven inline inspection robot, called Smart-Spider. The primary objective is to use this type of robot for offshore oil and gas pipeline inspection, especially for those pipelines where the conventional intelligent pigging systems could not or be difficult to be deployed. The Smart-Spider, which is real-time controlled by its own on-board MCU core and power supplied by a hugged-up battery, is expected to execute pipeline inspection in an autonomous manner. A flexible mechanism structure is applied to realize the spider's flexibility to adapt to different diameters of pipelines as well as to handle some irregular situations, such as to pass through an obstructed areas or to maneuver at a corner or junction. This adaptation is automatically controlled by the MCU controller based on pressure sensors' feedback. The equipped devices, such as the selected motors and battery package, as well as the human-and-machine interface are also discussed in detail. Some preliminary laboratory testing results illustrated the feasibility and cost-effectiveness of this design and development in a very promising manner.
The offshore de-oiling process is a vital part of current oil recovery, as it separates the profitable oil from water and ensures that the discharged water contains as little of the polluting oil as possible. With the passage of time, there is an increase in the water fraction in reservoirs that adds to the strain put on these facilities, and thus larger quantities of oil are being discharged into the oceans, which has in many studies been linked to negative effects on marine life. In many cases, such installations are controlled using non-cooperative single objective controllers which are inefficient in handling fluctuating inflows or complicated operating conditions. This work introduces a model-based robust H ∞ control solution that handles the entire de-oiling system and improves the system’s robustness towards fluctuating flow thereby improving the oil recovery and reducing the environmental impacts of the discharge. The robust H ∞ control solution was compared to a benchmark Proportional-Integral-Derivative (PID) control solution and evaluated through simulation and experiments performed on a pilot plant. This study found that the robust H ∞ control solution greatly improved the performance of the de-oiling process.
Purpose: The purpose of the paper is to identify the multiple types of data that can be collected and analyzed by practitioners across the cold chain, the ICT infrastructure required to enable data capture and how to utilize the data for decision making in cold chain logistics. Design/methodology/approach: Content analysis based literature review of 38 selected research articles, published between 2000 and 2016, was used to create an overview of data capture, technologies used for collection and sharing of data, and decision making that can be supported by the data, across the cold chain and for different types of perishable food products. Findings: There is a need to understand how continuous monitoring of conditions such as temperature, humidity, and vibration can be translated to support real-time assessment of quality, determination of actual remaining shelf life of products and use of those for decision making in cold chains. Firms across the cold chain need to adopt appropriate technologies suited to the specific contexts to capture data across the cold chain. Analysis of such data over longer periods can also unearth patterns of product deterioration under different transportation conditions, which can lead to redesigning the transportation network to minimize quality loss or to take precautions to avoid the adverse transportation conditions. Research limitations/implications: The findings need to be validated through further empirical research and modeling. There are opportunities to identify all relevant parameters to capture product condition as well as transaction data across the cold chain processes for fish, meat and dairy products. Such data can then be used for supply chain (SC) planning and pricing products in the retail stores based on product conditions and traceability information. Addressing some of the above research gaps will call for multi-disciplinary research involving food science and engineering, information technologies, computer science and logistics and SC management scholars. Practical implications: The findings of this research can be beneficial for multiple players involved in the cold chain like food processing companies, logistics service providers, ports and wholesalers and retailers to understand how data can be effectively used for better decision making in cold chain and to invest in the specific technologies, which will suit the purpose. To ensure adoption of data analytics across the cold chain, it is also important to identify the player in the cold chain, which will drive and coordinate the effort. Originality/value: This paper is one of the earliest to recognize the need for a comprehensive assessment for adoption and application of data analytics in cold chain management and provides directions for future research.