Articoli di riviste: "Shipping Mathematical models"

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Gençer, Hüseyin, e M. Hulusi Demir. "Optimization of Empty Container Repositioning in Liner Shipping". Business and Management Horizons 8, n. 1 (23 gennaio 2020): 1. http://dx.doi.org/10.5296/bmh.v8i1.16327.

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Empty container repositioning (ECR), which arises due to imbalances in world trade, causes extra costs for the container liner carrier companies. Therefore, one of the main objectives of all liner carriers is to reduce ECR costs. Since ECR decisions involve too many parameters, constraints and variables, the plans based on real-life experiences cannot be effective and are very costly. For this purpose, this study introduces two mathematical programming models in order to make ECR plans faster, more efficient and at the lowest cost. The first mathematical programming model developed in this study is a mixed-integer linear programming (MILP) model and the second mathematical programming model is a scenario-based stochastic programming (SP) model, which minimize the total ECR costs. Unlike the deterministic model, the SP model takes into account the uncertainty in container demand. Both models have been tested with real data taken from a liner carrier company. The numerical results showed that, in a reasonable computational time, both models provide better results than real-life applications of the liner carrier company.

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Vilenskii, O., S. Dushev, D. Lapshin, E. Novinskii e A. Tatarskii. "MATHEMATICAL ANALYSIS OF AIRCRAFT TURBINE COLLISION WITH SHIPPING PACKAGE". PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, n. 3 (26 settembre 2021): 106–22. http://dx.doi.org/10.55176/2414-1038-2021-3-106-122.

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The aim of the paper is to substantiate the developed shipping package integrity on the basis of mathematical analysis of postulated scenarios for the heaviest dynamic effects using verified behavior models for applied structural materials and modern certified finite element software package. The shipping package is permitted to transfer to the limiting condition in the result of impact, when its further operation is not acceptable, and recovery of its functional condition is not expedient, excluding the possibility of falling out of the nuclear fuel (NF) or distortion of the relative position of the NF in the shipping package. The paper presents main analysis results of the process of an aircraft turbine collision with a shipping package. The calculation analysis was performed using the dynamic calculation module LS-DYNA of the certified software package ANSYS. The LS-DYNA module is meant for computational analysis of high linear dynamic processes under explicit scheme of integration of the dynamics equations. The completed full-scale mathematical 3D modeling permitted to carry out sufficiently deep and detailed analysis of dynamic processes, reducing the design duration, and it permitted to reduce the self-cost of the developed design. The obtained results of mathematical analysis of shipping package behavior during interaction with aircraft turbine enabled to form the approach to substantiation of equipment safety in incidents. The detailed design study performed at the design stage formed basis for the final appearance of the developed structure.

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ABRAMOV, A. D., e G. S. ABRAMOV. "ANALYSIS OF MATHEMATICAL MODELS OF MARITIME SHIPPING TRENDS IN A CRISIS ENVIRONMENT". Applied Questions of Mathematical Modeling 4, n. 2.2 (2021): 16–24. http://dx.doi.org/10.32782/kntu2618-0340/2021.4.2.2.1.

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Field, David A., e Dennis E. Blumenfeld. "Supply Chain Inventories of Engineered Shipping Containers". International Journal of Manufacturing Engineering 2016 (5 dicembre 2016): 1–8. http://dx.doi.org/10.1155/2016/2021395.

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Manufacturing operations that assemble parts often receive components in expensive highly engineered shipping containers. As these containers circulate among suppliers, assembly operations, and logistic providers, they require inspections and repairs. This paper presents mathematical models that predict the number of available containers as functions of damage, repair times, and scheduled daily production. The models allow making complex decisions with a few basic parameters. Results not only show a minimal investment in the number of containers and safety stock but also quantify the dependence on damage rates and repair times for ordering additional containers.

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Dulebenets, Maxim A. "Advantages and disadvantages from enforcing emission restrictions within emission control areas". Maritime Business Review 1, n. 2 (30 giugno 2016): 107–32. http://dx.doi.org/10.1108/mabr-05-2016-0011.

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Purpose Emissions produced by oceangoing vessels not only negatively affect the environment but also may deteriorate health of living organisms. Several regulations were released by the International Maritime Organization (IMO) to alleviate negative externalities from maritime transportation. Certain polluted areas were designated as “Emission Control Areas” (ECAs). However, IMO did not enforce any restrictions on the actual quantity of emissions that could be produced within ECAs. This paper aims to perform a comprehensive assessment of advantages and disadvantages from introducing restrictions on the emissions produced within ECAs. Two mixed-integer non-linear mathematical programs are presented to model the existing IMO regulations and an alternative policy, which along with the established IMO requirements also enforces restrictions on the quantity of emissions produced within ECAs. A set of linearization techniques are applied to linearize both models, which are further solved using the dynamic secant approximation procedure. Numerical experiments demonstrate that introduction of emission restrictions within ECAs can significantly reduce pollution levels but may incur increasing route service cost for the liner shipping company. Design/methodology/approach Two mixed-integer non-linear mathematical programs are presented to model the existing IMO regulations and an alternative policy, which along with the established IMO requirements also enforces restrictions on the quantity of emissions produced within ECAs. A set of linearization techniques are applied to linearize both models, which are further solved using the dynamic secant approximation procedure. Findings Numerical experiments were conducted for the French Asia Line 3 route, served by CMA CGM liner shipping company and passing through ECAs with sulfur oxide control. It was found that introduction of emission restrictions reduced the quantity of sulfur dioxide emissions produced by 40.4 per cent. In the meantime, emission restrictions required the liner shipping company to decrease the vessel sailing speed not only at voyage legs within ECAs but also at the adjacent voyage legs, which increased the total vessel turnaround time and in turn increased the total route service cost by 7.8 per cent. Research limitations/implications This study does not capture uncertainty in liner shipping operations. Practical implications The developed mathematical model can serve as an efficient practical tool for liner shipping companies in developing green vessel schedules, enhancing energy efficiency and improving environmental sustainability. Originality/value Researchers and practitioners seek for new mathematical models and environmental policies that may alleviate pollution from oceangoing vessels and improve energy efficiency. This study proposes two novel mathematical models for the green vessel scheduling problem in a liner shipping route with ECAs. The first model is based on the existing IMO regulations, whereas the second one along with the established IMO requirements enforces emission restrictions within ECAs. Extensive numerical experiments are performed to assess advantages and disadvantages from introducing emission restrictions within ECAs.

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Xiao, Ruiqi, Lin Pan, Hanbin Xiao, Han Xiao e Ze Zhu. "Research of Intelligent Logistics and High-Quality Economy Development for Yangtze River Cold Chain Shipping Based on Carbon Neutrality". Journal of Marine Science and Engineering 10, n. 8 (27 luglio 2022): 1029. http://dx.doi.org/10.3390/jmse10081029.

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The current status of intelligent logistics and cold chain shipping research is a hot topic worldwide. Meanwhile, the study of regional logistics and regional economy, shipping logistics and regional economic theory and application methods, and the empirical analysis of the correlation between the Yangtze River shipping and the Yangtze River shipping economy have attracted a lot of attention. This research has revealed that the Internet of Things of Yangtze River shipping has a great impact on the Yangtze River and the importance of inland river economic development. This study presents the empirical analysis on the correlation between shipping logistics and the inland river economy, starting from qualitative and quantitative aspects, and taking Yangtze River shipping as the representative. The proposed mathematical models and qualitative data analysis are made on the relevant effects of intelligent logistics and cold chain shipping on an inland river economy including its impact on the industrial layout, international trade, and urbanization. The research results provide administrative decisions or guidance values for the economic development of inland river ports in the Yangtze River.

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Lim, Si-Yeong, e Sun Hur. "Determination of Optimal Shipping Quantity for Perishable Goods under Probabilistic Supply". Mathematical Problems in Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/274713.

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The problems of shipping and transporting perishable goods are commonly considered in the literature as significant topics, but rarely did researchers adopt a probabilistic point of view in their models. It is common in SCM environments that the participating entities’ behaviors are random and unpredictable and so can only be modeled in a probabilistic way. In this paper, we consider the shipping problem of determining the optimal quantity of perishable products with a limited time to be stored in the warehouse. The optimal quantity minimizes the overall operational costs including those of inventory and shipping. We develop a mathematical model, from which the probability distribution function, mean, and variance of the length of the build-up period are derived and we establish a cost function for determining the optimal shipping value.

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Jiang, Xi, Haijun Mao e Hao Zhang. "Simultaneous Optimization of the Liner Shipping Route and Ship Schedule Designs with Time Windows". Mathematical Problems in Engineering 2020 (22 dicembre 2020): 1–11. http://dx.doi.org/10.1155/2020/3287973.

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This paper proposes to address the problem of the simultaneous optimization of the liner shipping route and ship schedule designs by incorporating port time windows. A mathematical programming model was developed to minimize the carrier’s total operating cost by simultaneously optimizing the port call sequence, ship arrival time per port of call, and sailing speed per shipping leg under port time window constraints. In view of its structure, the nonlinear nonconvex optimization model is further transformed into a mixed-integer linear programming model that can be efficiently solved by extant solvers to provide a global optimal solution. The results of the numerical experiments performed using a real-world case study indicated that the proposed model performs significantly better than the models that handle the design problems separately. The results also showed that different time windows will affect the optimal port call sequence. Moreover, port time windows, bunker price, and port efficiency all affect the total operating cost of the designed shipping route.

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Zhang, Hengzhen, Lihua Lu e Xiaofeng Wang. "Tactical and Operational Cooperative Empty Container Repositioning Optimization Model Based on Business Flow and Initial Solutions Generation Rules". Symmetry 11, n. 3 (28 febbraio 2019): 300. http://dx.doi.org/10.3390/sym11030300.

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Due to the special role of empty containers in the container transportation process, empty container repositioning is a focal point in the shipping industry. For this problem, highly efficient and feasible optimization models are critical in improving the benefit for shipping companies and increasing their market competitiveness. Operational decisions are affected by tactical ones. Aimed at this point, we propose a tactical and operational cooperative empty container repositioning optimization model. To cut the search space and obtain the optimal solution quickly, several initial solutions generation rules are extracted, based on business flow. Furthermore, the reachable shipping distance may change when the calling sequence is different. An algorithm which calculates the reachable shipping distance matrix between ports is presented to solve this problem. Simulated cases are used to test the proposed model and algorithm. The results show that the cases can cope with the tactical and operational cooperative empty container repositioning optimization model. Moreover, some interesting conclusions also are deduced about the relationships among number of calling ports, total profits, leasing cost, calling port fee, number of Empty Containers Repositioned (ECR), and laden containers. All these can guide and assist the various decisions to be made. According to the homepage of Symmetry, its subject areas include Mathematics, Computer Science, Theory, and Methods. Their branches include information theory, computer-aided design, and so on. The topic of our paper is to solve this engineering application problem by using a mathematical optimization model and computer methods. That is, applying mathematical theory and computer methods to make decision results for the empty container repositioning problem in the shipping industry. It has certain economic value and practical significance. Obviously, it is consistent with the theme of Symmetry.

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Elmi, Zeinab, Prashant Singh, Vamshi Krishna Meriga, Krzysztof Goniewicz, Marta Borowska-Stefańska, Szymon Wiśniewski e Maxim A. Dulebenets. "Uncertainties in Liner Shipping and Ship Schedule Recovery: A State-of-the-Art Review". Journal of Marine Science and Engineering 10, n. 5 (21 aprile 2022): 563. http://dx.doi.org/10.3390/jmse10050563.

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Each shipping line is expected to establish a reliable operating model, and the design of ship schedules is a key operational consideration. Long-term profits for shipping lines can be expected from a well-designed ship schedule. In today’s liner service design, managing the time factor is critical. Shipping schedules are prone to different unexpected disruptions. Such disruptions would necessitate a near-real-time analysis of port capacity and re-design of the original ship schedule to offset the negative externalities. Ship schedule recovery strategies should be implemented to mitigate the effects caused by disruptions at ports or at sea, which may include, but are not limited to, ship sailing speed adjustment, handling rate adjustment at ports, port skipping, and port skipping with container diversion. A proper selection of ship schedule recovery strategies is expected to minimize deviations from the original ship schedule and reduce delays in the delivery of cargoes to the destination ports. This article offers a thorough review of the current liner shipping research primarily focusing on two major themes: (1) uncertainties in liner shipping operations; and (2) ship schedule recovery in response to disruptive events. On the basis of a detailed review of the available literature, the obtained results are carefully investigated, and limitations in the current state-of-the-art are determined for every group of studies. Furthermore, representative mathematical models are provided that could be further used in future research efforts dealing with uncertainties in liner shipping and ship schedule recovery. Last but not least, a few prospective research avenues are suggested for further investigation.

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Jackiva, Irina Yatskiv, Jurijs Tolujevs, Vladimirs Petrovs e Aleksejs Vesjolijs. "A Modelling System for Evaluating Options for Building and Using a Fleet of Battery Electric Trucks". Transport and Telecommunication Journal 23, n. 4 (1 novembre 2022): 334–43. http://dx.doi.org/10.2478/ttj-2022-0027.

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Abstract Many shipping companies tackle the challenge of potentially replacing conventional trucks with electric ones in economically developed countries. The aim of this work is to describe the principle of scaling models for analysing the operation of a fleet of vehicles, when the decision to use a particular type of model is made considering the accuracy and completeness of the initial data, as well as the goals of modelling. At the end of the report, information is provided on the TraPodSim simulation system developed by the authors, which is based on a multi-agent simulation model created using AnyLogic software. The paper considers modelling methods aimed at assessing the physical indicators of the transportation process. Various aspects of using three types of mathematical models are discussed: a) analytical deterministic models, b) analytical models using the Monte Carlo method and c) simulation models.

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Sitek, Paweł, e Jarosław Wikarek. "A Hybrid Approach to the Optimization of Multiechelon Systems". Mathematical Problems in Engineering 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/925675.

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In freight transportation there are two main distribution strategies: direct shipping and multiechelon distribution. In the direct shipping, vehicles, starting from a depot, bring their freight directly to the destination, while in the multiechelon systems, freight is delivered from the depot to the customers through an intermediate points. Multiechelon systems are particularly useful for logistic issues in a competitive environment. The paper presents a concept and application of a hybrid approach to modeling and optimization of the Multi-Echelon Capacitated Vehicle Routing Problem. Two ways of mathematical programming (MP) and constraint logic programming (CLP) are integrated in one environment. The strengths of MP and CLP in which constraints are treated in a different way and different methods are implemented and combined to use the strengths of both. The proposed approach is particularly important for the discrete decision models with an objective function and many discrete decision variables added up in multiple constraints. An implementation of hybrid approach in theECLiPSesystem using Eplex library is presented. The Two-Echelon Capacitated Vehicle Routing Problem (2E-CVRP) and its variants are shown as an illustrative example of the hybrid approach. The presented hybrid approach will be compared with classical mathematical programming on the same benchmark data sets.

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Wu, Jun Hui, Tong Di Qin, Jie Chen, Hui Ping Si, Kai Yan Lin, Qiang Zhou e Chi Bin Zhang. "Slotting Optimization Algorithm of the Stereo Warehouse". Advanced Materials Research 756-759 (settembre 2013): 1371–76. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.1371.

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In order to solve the problem of slotting optimization management with automated storage and retrieval system (AS / RS), the genetic algorithms of the slotting optimization process with stereo warehouse were discussed. The process of the slotting optimization was designed by the real-number coding. The mathematical models of the slotting optimization and cargo shipping time were built, and the simulation calculation of the models was done. The stability of the shelf and the efficiency of the accessing goods were significantly improved by the optimization simulation of the distribution of cargo space, after optimizing the storage order. The algorithms of the slotting optimization with stereo warehouse could effectively enhance the frequency of the stock in & out, increasing the revenue.

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Gençer, Hüseyin, e M. Hulusi Demir. "An Overview of Empty Container Repositioning Studies and Research Opportunities". Business and Management Horizons 7, n. 1 (16 aprile 2019): 1. http://dx.doi.org/10.5296/bmh.v7i1.14670.

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The imbalances in world trade also affect container traffic and lead to large differences in import and export rates of many locations. As a consequence of this, the surplus containers are repositioned to locations where they are required, which causes high costs. Many studies in the literature have addressed this issue from different aspects. This study examines the studies and trends in empty container repositioning (ECR) practices and reveals the missing research areas in the literature. It discusses the mathematical models developed in the literature and addresses real-life applications of the liner carriers. The study also emphasizes how the opportunities in technological development can be used in ECR practices and provides suggestions for research topics that can be studied in the light of current trends in container shipping. It exhibits the actors involved in ECR operations and discusses the strategies applied in liner shipping. The main purpose of the study is to put forward research and real-life application opportunities in the field of ECR.

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Cahyadi, Lina. "MODEL MATEMATIKA UNTUK MASALAH TRANSPORTASI LEBIH DARI SATU PRODUK [MATHEMATICAL MODELS FOR TRANSPORTATION PROBLEMS INVOLVING MORE THAN ONE PRODUCT]". FaST - Jurnal Sains dan Teknologi (Journal of Science and Technology) 6, n. 2 (30 novembre 2022): 103. http://dx.doi.org/10.19166/jstfast.v6i2.5340.

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Distribution companies need to plan efficient shipments to avoid incurring large shipping costs. Therefore, a company that addresses transportation problems by choosing the right distribution pattern can obtain optimal distribution costs. The transportation problem model is applied to allocate the same product to the destination places. In the problem of distributing more than one product, the transportation problem model is modified so that it can be used to optimize shipping costs. This study aimed to optimize distribution costs using a modified transportation problem model. The data obtained from the "Sejahtera" store included data on distribution costs, supply from sources, and requests from each store. The analysis was carried out by forecasting the demand for products processed by a time series process to assist companies in estimating the amount of demand for each product in the future. Then, optimization was carried out by testing the modified model for the transportation problem of more than one product under three conditions. Optimization of distribution costs was carried out by finding a feasible initial solution using the northwest corner method, the minimum cost method, and the modified Vogel's Approximation Method (VAM) approximation method, followed by determining the optimum solution using the stepping-stone method and the Modified Distribution Method (MODI). Based on the research conducted, the three conditions were tested using a modified transportation problem model for more than one product resulting in optimum shipping costs.Bahasa Indonesia Abstract:Perusahaan distibusi perlu merencanakan pengiriman yang efisien agar tidak mengeluarkan biaya pengiriman yang besar dengan meminimalkan biaya pengiriman. Oleh karena itu, perusahaan menerapkan masalah transportasi dalam memilih pola distribusi yang tepat untuk memperoleh biaya distribusi yangoptimal. Masalah transportasi diterapkan untuk mengalokasikan produk yang sama ke tempat-tempat tujuan. Dalam permasalahan pendistribusian lebih dari satu produk, model masalah transportasi dimodifikasi sehingga dapat digunakan untuk mengoptimalkan biaya pengiriman. Data diperoleh dari toko Sejahtera meliputi data biaya distribusi, persediaan dari sumber dan permintaan setiap toko yang bertujuan untuk mengoptimalkan biaya distribusi menggunakan model masalah transportasi yang dimodifikasi. Analisis dilakukan dengan meramalkan permintaan produk yang diolah dengan proses time series untuk membantu perusahaan dalam memperkirakan jumlah permintaan masing-masing produk untuk waktu yang akan datang. Kemudian melakukan optimasi dengan menguji model yang sudah dimodifikasi untuk masalah transportasi lebih dari satu produk dalam tiga kondisi. Optimasi biaya distribusi dilakukan dengan mencari pemecahan awal yang layak menggunakan metode sudut barat laut, metode biaya minimum dan metode aproksimasi Vogel’s Approximation Method (VAM) yang dimodifikasi dilanjutkan dengan menentukan solusi optimum menggunakan metode batu loncatan (stepping-stone) dan Modified Distribution Method (MODI) yang dimodifikasi. Berdasarkan penelitian yang dilakukan, ketiga kondisi yang diuji menggunakan model masalah transportasi yang dimodifikasi untuk lebih dari satu produk menghasilkan biaya pengiriman yang optimum.

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Bostina, Aurel, Alina Lucia Bostina, Nicoleta Acomi e Ovidiu Cristian Acomi. "Sea Trails of Large Container Ships". Advanced Materials Research 1036 (ottobre 2014): 952–56. http://dx.doi.org/10.4028/www.scientific.net/amr.1036.952.

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The container carrier shipping industry faces nowadays a similar phenomenon that happened in the 90s with crude oil carriers: an imaginable gigantism not-forecasted even by the most optimistic specialists. In the last 20 years the demand in transportation by containers continuously grew. The reaction of Carriers was quick under this demand growth and began an exacerbate competition not only in size of their fleets but in the size of their vessels as well. Before building a new vessel, a set of simulations and tests of prototypes and models is done, in order to apply corrections of the initial projects but, the practice showed that each vessel is different and its behavior at sea, too. In order to be acquainted to dealing with the various situations at sea, the true measurements of the vessels performance are done in her sea trials. The purpose of this paper is to update this Sea trials process, to detail it and to bring the contemporary element: measurement technologies, calculations, mathematical models.

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Kaup, Magdalena. "Functional model of river-sea ships operating in European system of transport corridors: Part I. Methods used to elaborate functional models of river-sea ships operating in European system of transport corridors". Polish Maritime Research 15, n. 3 (1 ottobre 2008): 3–11. http://dx.doi.org/10.2478/v10012-007-0077-y.

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Functional model of river-sea ships operating in European system of transport corridors: Part I. Methods used to elaborate functional models of river-sea ships operating in European system of transport corridors This paper presents a functional model of river-sea ships (shortly called: SRM) operating in European system of transport corridors. It is composed of two parts: Part I contains a descriptive model of functioning the SRM fleet with taking into account various shipping tasks as well as impact factors (external and internal factors, limitations and criteria). Also, a mathematical model of functioning the SRM fleet, including choice of relevant economic criteria (e.g. profit maximization, capital return period minimization etc), is presented. Results achieved on the basis of the functional model are presented in Part II of the paper.

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Chu, Zhong, e Ming Sun. "Simulation of the Main Engine Remote Control System for Marine Education and Training". Advanced Materials Research 328-330 (settembre 2011): 2367–71. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.2367.

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Training simulator is a necessary equipment for modern navigation education to accords with the demands of the STCW78/10 convention. A new type of simulation training system for main engine remote control has been successfully put into use for chief engineer’ training, which is the main part of the modern marine engine room simulator recently developed by Qingdao Ocean Shipping Mariners College and Dalian Maritime University. The simulation system, the simulated object of which are the Autochief 4 remote control system, the main engine with the type of MAN B&W 10L90MC and the pneumatic maneuvering system, has good simulation effect due to accurate mathematical models, nice human-machine interfaces and abundant troubles to shot. This paper introduces the innovative design, the plentiful functions of the simulation system and the application of IT.

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Pérez-Canosa, José M., José A. Orosa e Eliseo A. Pacheco. "A New Understanding and Modelling of TSP and BP Indices Compared to Safety IMO Ship Requirements". Applied Sciences 11, n. 15 (2 agosto 2021): 7142. http://dx.doi.org/10.3390/app11157142.

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Due to the lack of information about the concept of Tons of Steering Pull (TSP) of many escort tugs, and the lack of research works relating the TSP demanded by a tethered vessel with respect to the TSP provided by tugs, the present paper shows an original study with mathematical models on how to solve these problems. What is more, an important percentage of the towing sector always employs Bollard Pull (BP), which is considered the only parameter capable of defining performance, so this paper aims to relate BP with TSP. The present research was carried out based on more than 25 escort tugs of different towing companies. Furthermore, a real case study of different tanker vessels was used for modelling purposes of tethered vessels’ TSP. Finally, once the proposed models were obtained, they were compared with International Maritime Organization (IMO) guidelines. The results showed charts with the main independent variables of tugs and vessels in order to be as useful and practical as possible to the shipping industry, mainly to ship owners and tug operators, from a safety point of view.

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Cheng, Yuepeng, Bo Li e Yushan Jiang. "Optimal Choices for the E-Tailer with Inventory Rationing, Hybrid Channel Strategies, and Service Level Constraint under Multiperiod Environments". Mathematical Problems in Engineering 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/4659074.

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This paper investigates optimal choices for the e-tailer with inventory rationing, hybrid channel strategies, and service level constraint under multiperiod environment. Based on different operational conditions, five mathematical models are proposed for the e-tailer who faces two types of fuzzy demand and a framework is designed to illustrate the e-tailer’s operation in different models. This paper presents the advantages of inventory rationing and hybrid channel strategies and analyzes the influences of channel differences variability on optimal choices for the e-tailer, where the channel differences include margin difference of priority and margin difference of channel. Through computer simulation, the optimal choices for the e-tailer under different multiperiod environments are obtained, and the influences of margin difference of priority and margin difference of channel on the e-tailer’s optimal choices are also examined. Experiment results show that the pure-play drop shipping model and the hybrid channel with inventory rationing model are the optimal choices for the e-tailer; these findings have valuable guiding significance for the e-tailer to make optimal tactical decisions under multiperiod environment.

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Perčić, Maja, Nikola Vladimir, Ailong Fan e Ivana Jovanović. "Holistic Energy Efficiency and Environmental Friendliness Model for Short-Sea Vessels with Alternative Power Systems Considering Realistic Fuel Pathways and Workloads". Journal of Marine Science and Engineering 10, n. 5 (30 aprile 2022): 613. http://dx.doi.org/10.3390/jmse10050613.

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Energy requirements push the shipping industry towards more energy-efficient ships, while environmental regulations influence the development of environmentally friendly ships by replacing fossil fuels with alternatives. Current mathematical models for ship energy efficiency, which set the analysis boundaries at the level of the ship power system, are not able to consider alternative fuels as a powering option. In this paper, the energy efficiency and emissions index are formulated for ships with alternative power systems, considering three different impacts on the environment (global warming, acidification, and eutrophication) and realistic fuel pathways and workloads. Besides diesel, applications of alternative powering options such as electricity, methanol, liquefied natural gas, hydrogen, and ammonia are considered. By extending the analysis boundaries from the ship power system to the complete fuel cycle, it is possible to compare different ships within the considered fleet, or a whole shipping sector, from the viewpoint of energy efficiency and environmental friendliness. The applicability of the model is illustrated on the Croatian ro-ro passenger fleet. A technical measure of implementation of alternative fuels in combination with an operational measure of speed reduction results in an even greater emissions reduction and an increase in energy efficiency. Analysis of the impact of voluntary speed reduction for ships with different power systems resulted in the identification of the optimal combination of alternative fuel and speed reduction by a specific percentage from the ship design speed.

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Sahin, Bekir, Devran Yazir, Abdelsalam Adam Hamid e Noorul Shaiful Fitri Abdul Rahman. "Maritime Supply Chain Optimization by Using Fuzzy Goal Programming". Algorithms 14, n. 8 (9 agosto 2021): 234. http://dx.doi.org/10.3390/a14080234.

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Fuzzy goal programming has important applications in many areas of supply chain, logistics, transportation and shipping business. Business management has complications, and there exist many interactions between the factors of its components. The locomotive of world trade is maritime transport and approximately 90% of the products in the world are transported by sea. Optimization of maritime operations is a challenge in order to provide technical, operational and financial benefits. Fuzzy goal programming models attract interests of many scholars, therefore the objective of this paper is to investigate the problem of minimization of total cost and minimization of loss or damage of containers returned from destination port. There are various types of fuzzy goal programming problems based on models and solution methods. This paper employs fuzzy goal programming with triangular fuzzy numbers, membership functions, constraints, assumptions as well as the variables and parameters for optimizing the solution of the model problem. The proposed model presents the mathematical algorithm, and reveals the optimal solution according to satisfaction rank from 0 to 1. Providing a theoretical background, this study offers novel ideas to researchers, decision makers and authorities.

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Gong, Intaek, Kyungho Lee, Jaewon Kim, Yunhong Min e KwangSup Shin. "Optimizing Vehicle Routing for Simultaneous Delivery and Pick-Up Considering Reusable Transporting Containers: Case of Convenience Stores". Applied Sciences 10, n. 12 (17 giugno 2020): 4162. http://dx.doi.org/10.3390/app10124162.

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Abstract (sommario):

Previous studies have proposed various frameworks and algorithms to optimize routes to reduce total transportation cost, which accounts for over 29.4% of overall logistics costs. However, it is very hard to find cases in which mathematical models or algorithms are applied to practical business environment cases which require reusable packaging, especially daily operating logistics services like convenience store support systems. Most previous studies have considered developing an optimal algorithm which can solve the mathematical problem within a practical amount of time while satisfying all constraints, such as the capacity of delivery and pick-up, and hard or soft time windows. For daily delivery and pick-up services, like those supporting several convenience stores, it is required to consider the unit transporting the container, as well as the demand, capacity of trucks, travel distance, and traffic congestion. In particular, reusable transport containers and trays should be regarded as important assets of logistics centers. However, if the mathematical model focuses on only satisfying constraints related to delivery and not considering the cost of trays, it is often to leave the empty trays on the pick-up points when there is not enough space in the track. In this study, we propose a mathematical model for optimizing delivery and pick-up plans by extending the general vehicle routing problem of simultaneous delivery and pick-up with time windows, while considering left-over cost. With numerical experiments it has been proved that the proposed model may reduce the total delivery cost. Also, it seems possible to apply the proposed approach to the various logistics businesses which require reusable transport containers like shipping containers, refrigerating containers, trays, and pallets.

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24

Wang, Zhongcheng, Xiaoyu Liu e Ke Li. "Study of Absorbing CO2 from Emissions Using a Spray Tower". Atmosphere 13, n. 8 (18 agosto 2022): 1315. http://dx.doi.org/10.3390/atmos13081315.

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In order to reduce the environmental impact caused by CO2 emissions from ships and achieve the goal of green shipping, a spray tower using NaOH solution for the absorption of CO2 has been established in this paper. Using the characteristics of a 6135G128ZCa marine diesel engine, the CO2 absorption system was designed and mathematical models of CO2 absorption efficiency were developed. The effects of the variation in engine exhaust gas temperature, the concentration of NaOH solution, the exhaust gas velocity, different load conditions, and different nozzle types on the absorption efficiency of CO2 were thoroughly investigated experimentally. Moreover, the mechanism of CO2 absorption was analyzed. The developed model was verified by comparing the test results with the simulation results. The results of the study proved that using NaOH solution to absorb CO2 from ship exhausts could reduce the level of CO2 emissions from ships by more than 20%, which indicates that this technology could be used in the future to reduce the level of CO2 emissions from ships.

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25

Surov, Oleg E., Maksim V. Kitaev, Ekaterina E. Solovieva, Vitaly A. Veselov e Dmitry V. Tyuftyaev. "Analysis of main dimensions and characteristics of fishing vessels". Russian Journal of Water Transport, n. 72 (20 settembre 2022): 41–53. http://dx.doi.org/10.37890/jwt.vi72.273.

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Abstract (sommario):

Fishing vessels are one of the most numerous and popular types of vessels of the fishing fleet of the Russian Federation. Fishing vessels provide food security of the country and contribute to employment in fishery areas and processing of marine biological resources, design, construction, operation, repair and modernization of fishery vessels. The existing fishery vessels of Russian Federation are largely morally and physically obsolete. The average age of this type of vessels is 30-35 years, which has a significant impaction on frequency repairs and reduces of their technical and economic performances. In this regard, the question arises of replenishing the fishing fleet with new types of vessels using advanced methods for their design. The development of mathematical models of fishing vessels allows, at the initial stages of their design, to perform the detailed analysis of their economic efficiency under given operating conditions. At first for the models development it is necessary to have the analytical dependencies which are connected of their main dimensions with design characteristics. This article presents the results of the analysis of the main dimensions and main characteristics of fishing vessels that have the class of the Russian Maritime Register of Shipping (RMRS). The data source was the Register Book of RMRS in current version (2022), which contains the information about sea-going self-propelled vessels with a gross tonnage of 100 tons and more. In our study we analyzed more than a thousand fishing vessels with different dimensions and characteristics. As an analysis results were made the decomposition of fishing fleet by age, degree of automation and construction country, ice class and other characteristics. Based on the methods of statistical analysis the analytical dependences for main dimensions and design characteristics of fishing vessels were obtained. The analytical dependencies can be used for the development of mathematical models of fishing vessels at the initial stages of their design.

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26

Buneev, Viktor M., Evgeny A. Grigoriev e Anna Yu Gavrilova. "Typical solutions for the organization of the transport process and systems in inland waterway transport". Russian Journal of Water Transport, n. 72 (20 settembre 2022): 156–66. http://dx.doi.org/10.37890/jwt.vi72.286.

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Abstract (sommario):

The necessity of making standard decisions in the organization of transport processes and systems is substantiated. The use of them allows you to reduce the time for their development and avoid mistakes during implementation in the operational activities of shipping companies. In addition, it is necessary to monitor the progress of the task, since there is a certain time period during which changes in the production conditions of transport can occur. Situations, their dynamism in time and space, indicators of the organization of transport activities are subject to assessment. This is the relevance of this work. For its implementation within the framework of the shipping company, appropriate organizational-technical and organizational-economic measures of a general nature are recommended. In this regard, the specific, most important tasks are considered: 1) justification of schemes and methods of organizing transportation and fleet operations; 2) development of requirements for vessels for use in the main directions of cargo transportation; 3) justification of the rational scope of use of types of vessels and convoys in cargo transportation; 4) optimization of standard convoys and determination of their list in the main directions of cargo transportation; 5) optimization of the layout plan of vessels and convoys by work areas and directions of transportation, taking into account the distribution by navigation periods; 6) justification of the operating mode of engines and the movement of tugboats with a composition. To solve them, methodological tools have been developed, the basis of which are scientific approaches and principles, methods and models of mathematical programming, features of operational and economic justification for water transport. The results of its implementation are the proposed standard solutions in the field of organization of the transport process and systems in inland waterway transport, scientifically based proposals and recommendations for choosing a strategy for using the fleet in cargo transportation and its distribution by navigation periods.

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27

Wang, Chia-Nan, Ngoc-Ai-Thy Nguyen, Hsin-Pin Fu, Hsien-Pin Hsu e Thanh-Tuan Dang. "Efficiency Assessment of Seaport Terminal Operators Using DEA Malmquist and Epsilon-Based Measure Models". Axioms 10, n. 2 (31 marzo 2021): 48. http://dx.doi.org/10.3390/axioms10020048.

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Abstract (sommario):

Today, over 80% of global trade is seaborne. In a world of global supply chains and complex industrial development processes, seaports and port operators play an integral role of utmost importance and act as an incentive to the development of the marine economy and particularly, the national economy in general. Most importantly, the supply chain and demand shocks of Covid-19 on container ports and the container shipping industry have intensified competition among terminal operators. Thus, it is imperative that managers evaluate competitiveness by measuring their past and current performance efficiency indexes. In so doing, we present a hybrid data envelopment analysis (DEA) model that combines the DEA Malmquist method and the epsilon-based measure (EBM) for the first time to address the issue of performance evaluation of seaport terminal operators. The applicability of the proposed hybrid approach is illustrated with a case study of the top 14 seaport companies in Vietnam. First, the Malmquist model is used to assess the total productivity growth rates of the companies, and its decomposition into technical efficiency change (catch-up) and technological investment (frontier-shift). Second, the EBM model is used to calculate the efficiency and inefficiency score of each company. Besides indicating the best-performing companies from certain aspects during the research period (2015–2020), the results reflect that the gap of applying the EBM method in the field of the maritime industry was successfully addressed, and together with the Malmquist model, the integrated framework can be an effective and equitable evaluation model for any area. Furthermore, the managerial implication provides a useful guideline for practitioners in the maritime sector in improving their operational efficacy and helps customers in selecting the best seaport companies in the outsourcing strategy.

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28

Muraveva, L. V., e I. G. Ovchinnikov. "AN ENGINEERING APPROACH TO ASSESSING THE CONSEQUENCES OF AN UNDERWATER EXPLOSION AND EVALUATING THE STRUCTURAL INTEGRITY OF AN UNDERWATER BURIED PIPELINE IS PRESENTED". EurasianUnionScientists 1, n. 3(72) (15 aprile 2020): 53–67. http://dx.doi.org/10.31618/esu.2413-9335.2020.1.72.617.

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Introduction: The performance of oil and gas pipeline systems under operational and natural loads is an important engineering indicator. In the new century, energy resources and methods of transportation have improved. We have abundant supplies of natural gas and oil; nuclear power plants. Renewable energy sources are being introduced, which increase production efficiency and improve the country's energy portfolio. Achievements in the field of energy efficiency allow to reduce energy costs of producers. Our energy infrastructure needs largescale investments, construction, but developers face new challenges. The structural integrity of an underwater pipeline exposed to an underwater explosion is an important task. The simulation of a submerged underwater pipeline as a pipeline-water-ground system is considered, taking into account the influence of the water environment, the soil base and the explosion of the transported medium. The work was carried out to ensure and develop security requirements for existing and future offshore projects. The purpose of this work is to present an engineering approach to the assessment of the consequences of an underwater explosion and to assess the structural integrity of an offshore buried pipeline. Materials and methods: The existing approaches are based on the applied mathematical models for assessing the integrity of the structure under explosive influences, taking into account the internal energy of the structure. Results: Proposals to the requirements for ensuring the safety of buried subsea pipelines with the water medium under the influence of the explosion of the transported medium and the elastic energy of the pipeline. The proposals are submitted for consideration to the Russian Maritime Register of Shipping. Studies have been carried out to determine the safe distance between two underwater pipelines. Conclusions: The results were obtained empirically using finite element models of the pipeline-water-soil system to assess the safety of the offshore buried pipeline taking into account the elastic energy of the structure.

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29

Bielawska, Michalina, Oskar Czechowski, Ernest Czermański, Aneta Oniszczuk-Jastrząbek e Tomasz Owczarek. "A preliminary evaluation of the impact of Sulphur Emissions Control Area in the Baltic Sea on air quality in port cities. Case port – the city of Gdańsk". SHS Web of Conferences 58 (2018): 01002. http://dx.doi.org/10.1051/shsconf/20185801002.

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The purpose of this research is to attempt to evaluate the extent, to which technical standards related to marine fuels and thereby also sulphur dioxide (SO2) content in engine exhausts from vessels operating on the Baltic Sea have been effective in curbing the negative impact of marine shipping on air quality, in particular in port cities. Marine environment protection is governed by the provisions of the MARPOL 73/78 International Convention, which Poland ratified as a party. Different areas of concern for marine shipping have been regulated in separate Appendices to the Convention. The first step was to introduce severe restrictions on SOx emissions in view of the fact that heavy marine fuel is the lowest-quality kerosene-derived fuel with a large content of sulphur. A gradual process was put in place to reduce its content in marine fuel. As a consequence, the world’s marine areas were divided into sulphur emission control areas (also known as SECA) and other areas. In Europe, these areas include the entire Baltic Sea and large portions of the North Sea. Another important technical and economic measure was to lower the limit of sulphur content in marine fuel to 0.1% in all SECA areas, with the limits remaining unchanged in the other areas. Two dates were of key importance for the investigation: 2010, when the reduction in sulphur content of marine fuels from 1.5% to 1% was mandated, and 2015, when the standard for sulphur content was dramatically lowered to 0.1%. In the first stage, the concentration of sulphur dioxide was researched as one of the factors preceding air contamination with suspended particles in the Gdańsk - Gdynia area in the period from 2005 to 2016, as investigated by four automatic reference measurement stations in the ARMAAG network (hourly data) located in the immediate vicinity of the sea (AM4, AM5, AM6 and AM8). The research concerned the arrival of high concentrations of sulphur blown in from the sea by the wind. Another key factor was the secondary data on the number of ships, in the form of monthly series, starting from 2007. The analysis was performed in stages. In the first stage, the quality of measurement and secondary data were evaluated using a unique data quality assessment method. Further on, Principal Component Analysis (PCA) models were constructed to identify spatial correlations between SO2 concentration distributions, which were used later as a basis on which to determine synthetic measures of average hourly concentrations for the entire agglomeration area. Subsequently, the impact of the SO2 source (influx from the Baltic Sea to the agglomeration areas) was gauged separately for each individual station. The PCA models constructed on the basis of hourly data corroborated the synthetic measures as correct, making it possible to identify the similarity of concentration distributions across the investigated stations. Multi-Dimensional Regression Models and Generalized Regression Models (GRM) have made it possible to identify the period, in which the concentration of sulphur dioxide dropped steadily (from 2010 to 2016), as well as the seasonal impact of variation in SO2 concentration and the number of ships. The hourly data was converted to average monthly, quarterly and annual values, depending on the mathematical model and purpose of research.

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30

Luu, Do Duc, Cao Duc Hanh e Luong Cong Nho. "Automatic Predicting Torsional Vibrations on Main Propulsion Plants, Installed Two-Stroke Diesel Engines: Algorithms and Software". Applied Mechanics and Materials 902 (settembre 2020): 1–12. http://dx.doi.org/10.4028/www.scientific.net/amm.902.1.

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The main propulsion plant (MPP) on marine sea-going ships consisting of a diesel engine as the main engine and driving the ship propeller is with the torsional vibrations to be calculated in accordance with the Rules for the Classification and Construction of Sea-Going Ships. The Rules are given by one of maritime registers in the world that are the members of IACS, such as Russian Maritime Register of Shipping (RMR), DNV, ABS, at el. The TV calculation (TVC) on the MPP usually is certainly a monumental calculation task and is conducted with special software for TVC. Nowadays, in accordance with the Rules, almost modern software products for TVC have the abilities to calculate the TVs at normal working regimes and at misfire regimes (called by Normal or Misfire regimes relatively) with only one of cylinders of marine diesel engine (MDE) while engine speed range covers from the minimum to maximum values of the operation speeds. The paper presents improved algorithms and software for automatic calculating the TVs (SATVC) at the Normal and the Misfire regimes, in which the misfiring processes appear not only in one cylinder, but also in two of the MDE cylinders together. The SATVC was based on the made mathematical models, algorithms and coded in LabView by authors. The SATVC consists of modules for automatic calculation of freedom TVs (FTVs), excited torsional moments (ETM), excited TVs (ETVs), permitted torsional pressures (PTP), and common management (CTVC). TVC at every working regime of MDE was automatically conducted in the following procedure: Configuration of the MPP for TVC; Calculation of FTVs; Calculation of ETM; Calculation of ETVs); Calculation of ETVs, and solution of the TVC in considered working regime. The working regime of MDE was modeled by a vector of firing coefficients (VFC) of every MDE cylinder.

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31

Muravieva, Lyudmila V., e Igor G. Ovchinnikov. "Problems of simulating subsea pipeline condition on the arctic shelf under seismic impact". Vestnik MGSU, n. 11 (novembre 2019): 1456–65. http://dx.doi.org/10.22227/1997-0935.2019.11.1456-1465.

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Introduction. The paper represents an approach to studying a model of interaction of a system ‘pipeline – soil’ under conditions of frost penetration and seismic impact. The given problem is connected with the reclamation of the shelf of the Russian sector of the Arctic. There is a feature of induced earthquakes connected with hydrocarbon production. These earthquakes occur in a few years after the beginning of field development and lead to the worst condition of the pipelines. The research aims to the development of a method for subsea pipeline strength assessment allowing for nonlinear properties of an elastic foundation under the seismic impact. Materials and methods. The research is based on mathematical models of structural strength assessment under seismic conditions in the Arctic. The results are empirically obtained from the safety assessment method for a subsea pipeline under the seismic impact. The work was performed by the procedure of the analysis of existing arctic offshore projects. Results. The paper develops suggestions on the analysis of subsea pipelines on a nonlinear elastic foundation under conditions of a seismic impact. The suggestions were submitted for consideration to the Russian Maritime Register of Shipping. Buried below the seabed, the subsea pipelines provide an efficient and safe mode of transporting energy resources. Issues of relations of the subsea pipelines with surrounding and frozen ground are considered, pipeline thermal operation modes and seismic risks resulting in damages to the pipelines are taken into account. Conclusions. Solving the problem of the subsea pipeline condition assessment under arctic conditions is of practical interest in developing energy resource transportation ways. Simulation of a subsea “hot” pipeline is considered allowing for the nonlinearity of elastic foundation properties and seismic impact.

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32

Kholoptsev, Aleksandr V., e Sergey A. Podporin. "IMPACT OF FLOODS IN THE KOLYMA RIVER DELTA ON NAVIGATION CONDITIONS IN THE EAST SIBERIAN SEA". Vestnik Gosudarstvennogo universiteta morskogo i rechnogo flota imeni admirala S. O. Makarova 14, n. 4 (13 settembre 2022): 563–70. http://dx.doi.org/10.21821/2309-5180-2022-14-4-563-570.

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The problem of improving the quality of medium- and long-term forecasting of changes in the ice situation on the Northern Sea Route, and in particular in the East Siberian Sea, where one of the methods for choosing waterways is the passage of vessels in the areas of flaw polynya, is considered. The hypothesis that in the summer months such changes can be significantly affected by the terms of floods onset in the Kolyma River Delta is tested. The data of the GLORYS12v1 global reanalysis supported by the Copernicus Marine Service are used as factual material on the ice cover and levels of the East Siberian Sea in the months from May to October of 1993-2019. The reanalysis is based on mathematical models of the NEMO family, verified using altimetry data from satellite measurements. Using the developed methodology for the selected periods of the year, the dates of sharp changes in the level and ice cover on the pre-estuary seaside of the Kolyma River are estimated. Using statistical methods, the validity of the stated hypothesis for a number of the East Siberian Sea areas, along which the shipping lanes of the Northern Sea Route pass, is confirmed. It has been established that the greatest influence of the floods terms on the ice situation and navigation conditions in such areas takes place in July. It has been shown that early floods in the Kolyma delta generally lead to an improvement in the ice situation, and late floods lead to its complication. The identified relationships are recommended for use in forecasting changes in ice conditions. The assumption that with further climate warming and a shift in the flood terms to earlier dates, it is possible that the ice conditions will become more complicated due to the freezing of the formed polynya, is made.

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33

Alekseev, Dmitrii V., e Alexander A. Lentarev. "COMPARATIVE ANALYSIS OF DATABASES ON OIL AND PETROLEUM PRODUCTS SPILLS FROM SHIPS". Vestnik Gosudarstvennogo universiteta morskogo i rechnogo flota imeni admirala S. O. Makarova 14, n. 6 (26 dicembre 2022): 891–904. http://dx.doi.org/10.21821/2309-5180-2022-14-6-891-904.

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Abstract (sommario):

In the context of the growing demand of developing and developed countries for oil and its derivatives, there is a positive trend in the production and transportation of hydrocarbons, mainly by sea. The combination of these processes increases the probability of environmental pollution. Moreover, the greatest pollution is associated precisely with shipping activities, when a significant amount of oil enters the seas and oceans as a result of accidents with ships. It is well known that detailed databases of oil spills are a necessary tool for realistic statistical analysis, the main purpose of which is to develop a system of methods to reduce oil and its products spills in the future. A comprehensive study of such international, national and corporate databases, as well as the analysis of the statistical data given in them is considered in the paper. Particular attention is paid to assessing the reliability of these data and their dependence on various factors. In the course of the study, methods of mathematical distribution of data with the construction of trend lines in some cases are used. Through the analysis, the fact of a decrease in the total number and volume of oil and oil products spills from sea vessels is established. It is also found that information on spills in some databases is not true, and some databases are completely closed. It is proposed to create in Russia a unified open database on oil and its products spills. Among other things, an inversely proportional relationship between the probability of an event and the damage from it is proved; small spills of oil and its products occur more often than large ones. The results of this relationship can be used in the development of models for assessing the oil spills probability and the damage.

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34

Kholoptsev, Alexander, Sergei Podporin e Evgeniy OlKhovik. "Impact of Floods in the Kolyma River Delta on Navigation Conditions in the East Siberian Sea". E3S Web of Conferences 363 (2022): 01004. http://dx.doi.org/10.1051/e3sconf/202236301004.

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Abstract (sommario):

Problem of improving the quality of medium- and long-term forecasting of changes in ice conditions in the Northern Sea Route, and in particular in the east Siberian sea, where one of the methods of selecting waterways is the passage of ships in areas of ice-covered polynya. The hypothesis is verified that during the summer months, such changes may be significantly influenced by the timing of the onset of high water in the Kolyma River delta. Data from the global reanalysis GLORYS12v1 supported by the European Copernicus Marine Service were used as factual material on the ice cover and levels of the East Siberian Sea in the months of May to October 1993-2019. The analysis is based on mathematical models of the NEMO family verified by satellite altimetry data. Using the developed methodology, the dates of abrupt changes in level and sea ice extent on the Kolyma River estuarine seashore have been estimated for selected periods of the year. The study uses statistical methods to confirm the validity of the stated hypothesis for a number of areas of the East Siberian Sea, through which the shipping routes of the Northern Sea Route pass. It has been established that the greatest influence of flood timing on ice conditions and navigation conditions in such areas takes place in July. It is shown that early floods in the Kolyma delta generally lead to improvement of ice conditions, while late floods lead to complication of ice conditions. The identified relationships are recommended for use in forecasting changes in ice conditions. It has been suggested that with further climate warming and shifting of flood dates to earlier dates, the complication of ice conditions due to freezing of the formed polynya is not excluded.

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35

Purwono, Novi. "ANALISA KEJADIAN GELOMBANG DENGAN METODE EMPIRIK DAN MODEL MATEMATIK DI KAWASAN PERAIRAN PELABUHAN TANJUNG LAUT". Gorontalo Journal of Infrastructure and Science Engineering 3, n. 1 (1 aprile 2020): 1. http://dx.doi.org/10.32662/gojise.v3i1.862.

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Abstract (sommario):

Tanjung Laut is water located in the administrative area of Bontang Regency, East Kalimantan. These waters are widely used for ship traffic to and from the Port. To find out the hydrodynamic conditions, especially waves that occur in the sea and propagate into these waters, it is necessary to analyze wave transformations to describe the conditions and impacts that occur due to wave propagation from the high seas that enter the port waters. The purpose of this study is to look at the shipping security channel. The method used in analyzing wind data from BMKG into wave data and modeling with cgwave mathematical models. Wave analysis is carried out with a cgwave model mathematical to determine the hydrodynamic conditions of the waves and to determine the shipping obstacles and to describe the plan waves that occur as one of the bases in determining the elevation of the pier and port breakwater structures. The results showed the conversion of wind speed and direction to be high, the period and direction of waves in the waters of Tanjung Laut in 2006-2016. The maximum significant wave height in the waters of Tanjung Laut occurred in 2007 was 3.91 meters with a period of 7.89 seconds. The results of statistical analysis using the wave recurrence method show that the wave height can occur or exceed for a 50 year return period is 4.80 meters to 5.54 meters, while the 10 year return period is 3.70 meters to 4.17 meters. The results of the waveform simulation with the cgwave are the wave height in the harbor pool ranging from 0.03 meters to 0.06 meters in the direction of waves from the Northeast, 0.03 meters to 0.07 meters in the direction of waves from the East, and 0.05 meters up to 0.09 meters in the direction of waves from the Southeast. Simulation results show that the conditions in the port pond are quite safe and calm against wave attacksTanjung laut merupakan pelabuhan perairan yang berada di wilayah administrasi Kabupaten Bontang Kalimantan Timur, dimana banyak digunakan untuk lalu lintas kapal yang menuju dan keluar dari Pelabuhan. Untuk mengetahui kondisi hidrodinamika khususnya gelombang yang terjadi di laut dan merambat ke perairan tersebut, perlu adanya analisa transformasi gelombang untuk menggambarkan kondisi dan dampak yang terjadi akibat perambatan gelombang dari laut lepas yang masuk ke kawasan perairan pelabuhan. Tujuan dari penelitian ini adalah untuk melihat keamanan alur pelayaran. Metode yang digunakan yaitu menganalisa data angin dari BMKG menjadi data gelombang dan pemodelan dengan model matematik cgwave. Analisa gelombang dilakukan dengan model matematik model cgwave untuk mengetahui kondisi hidrodinamika gelombang dan untuk mengetahui hambatan pelayaran serta untuk menggambarkan gelombang rencana yang terjadi sebagai salah satu dasar dalam penentuan elevasi dermaga dan bangunan pemecah gelombang pelabuhan. Hasil penelitian menunjukan konversi kecepatan dan arah angin menjadi tinggi, periode dan arah gelombang di perairan Tanjung laut Tahun 2006-2016. Tinggi gelombang signifikan maksimum di perairan Tanjung Laut terjadi pada tahun 2007 adalah 3,91 meter dengan periode 7,89 detik. Hasil analisa statistik menggunakan metode kala ulang kejadian gelombang, menunjukkan tinggi gelombang dapat terjadi atau terlampaui untuk kala ulang 50 tahun adalah 4,80 meter sampai dengan 5,54 meter, sedangkan kala ulang 10 tahun adalah 3,70 meter sampai dengan 4,17 meter. Hasil simulasi trasformasi dgelombang dengan model cgwave adalah tinggi gelombang di kolam pelabuhan berkisar antara 0,03 meter sampai dengan 0,06 meter dengan arah datang gelombang dari Timur Laut, 0,03 meter sampai dengan 0,07 meter dengan arah datang gelombang dari Timur, dan 0,05 meter sampai dengan 0,09 meter dengan arah datang gelombang dari Tenggara. Hasil simulasi menunjukkan kondisi di kolam pelabuhan cukup aman dan tenang terhadap serangan gelombang.

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36

Trenham, Claire E., e Larry K. Forbes. "A comparison of two- and three-variable models for combustion in sealed containers". ANZIAM Journal 47, n. 4 (aprile 2006): 527–40. http://dx.doi.org/10.1017/s1446181100010117.

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AbstractThis paper analyses a model for combustion of a self-heating chemical (such as pool chlorine), stored in drums within a shipping container. The system is described by three coupled nonlinear differential equations for the concentration of the chemical, its temperature and the temperature within the shipping container. Self-sustained oscillations are found to occur, as a result of Hopf bifurcation. Temperature and concentration profiles are presented and compared with the predictions of a simpler two-variable approximation for the system. We study the period of oscillation and its variation with respect to the ambient temperature and the reaction parameter. Nonlinear resonances are found to exist, as the solution jumps between branches having different periods.

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Yu, Yao, Jincheng Tu, Kun Shi, Mei Liu e Jihong Chen. "Flexible Optimization of International Shipping Routes considering Carbon Emission Cost". Mathematical Problems in Engineering 2021 (10 febbraio 2021): 1–9. http://dx.doi.org/10.1155/2021/6678473.

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Abstract (sommario):

Carbon emissions cost is a potential effective measure to restrict hydrocarbon pollution in the international shipping trade. The minimization of the total cost is pursued by ship operators, whereas voyage cost is increasingly involving the replacement of clean fuel and changing the cost of the shipping route. A flexible optimization method focusing on maximizing the total profit is developed in terms of sailing speed optimization and single port skips integrate carbon emission influence. An actual ocean shipping route from Shanghai to Rotterdam is applied to validate the effectiveness of the proposed models. The results have shown that the shipping route profit is volatile along with the sailing speed and the number of port calls. However, the profit will be maximized when applying the single port skip and will slow down the sailing speed at the same time. The demand of planned skip port can be supported by a short line container. A system composed of ocean container liner and short line container can improve the profit by 4.05% and reduce the carbon emission by 19.70%. Furthermore, sensitive results show that the profit is less affected by the changing of the carbon emission cost. A small size container has enough ability to solve the short transportation demand in adjacent ports and convert extraberthing cost into profit. These findings can provide reliable support for the shipping route decision process considering future carbon emission costs.

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38

Xu, Yisong, e Xinyu Zhuang. "Container Shipping Scheduling Method Based on the Evidence Reasoning Approach in Fluctuating CCFI and BDI Cycle". Mathematical Problems in Engineering 2022 (18 luglio 2022): 1–10. http://dx.doi.org/10.1155/2022/3997361.

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Due to the COVID-19/Omicron pandemic and the trade war and tariffs between China and America, the supply chain between Asia and America, or Asia and Europe, faced unprecedented challenges. With the outbreak of the Russian-Ukrainian war, the global supply chain has become increasingly unbalanced. In particular, the shortage of container ships and the continuous fluctuation of the BDI and CCFI make shipping scheduling increasingly important for ocean carriers. To solve this problem, in this study, we propose an analytic approach considering the fluctuation of BDI and CCFI based on interval evidence reasoning and the Hungarian algorithm. The proposed approach uses two pairs of nonlinear optimisation models to construct a Nash equilibrium assignment model to compute the shipping company’s scheduling and maximum utility in the CCFI and BDI cycles. Compared to the simulation algorithm, the analytical algorithm can take advantage of stability and efficiency. Finally, a COSCO company’s container shipping scheduling problem was examined to demonstrate the efficiency and effectiveness of the proposed approach.

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Dentener, Frank, Lisa Emberson, Stefano Galmarini, Giovanni Cappelli, Anisoara Irimescu, Denis Mihailescu, Rita Van Dingenen e Maurits van den Berg. "Lower air pollution during COVID-19 lock-down: improving models and methods estimating ozone impacts on crops". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, n. 2183 (28 settembre 2020): 20200188. http://dx.doi.org/10.1098/rsta.2020.0188.

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We suggest that the unprecedented and unintended decrease of emissions of air pollutants during the COVID-19 lock-down in 2020 could lead to declining seasonal ozone concentrations and positive impacts on crop yields. An initial assessment of the potential effects of COVID-19 emission reductions was made using a set of six scenarios that variously assumed annual European and global emission reductions of 30% and 50% for the energy, industry, road transport and international shipping sectors, and 80% for the aviation sector. The greatest ozone reductions during the growing season reached up to 12 ppb over crop growing regions in Asia and up to 6 ppb in North America and Europe for the 50% global reduction scenario. In Europe, ozone responses are more sensitive to emission declines in other continents, international shipping and aviation than to emissions changes within Europe. We demonstrate that for wheat the overall magnitude of ozone precursor emission changes could lead to yield improvements between 2% and 8%. The expected magnitude of ozone precursor emission reductions during the Northern Hemisphere growing season in 2020 presents an opportunity to test and improve crop models and experimentally based exposure response relationships of ozone impacts on crops, under real-world conditions. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

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Aulin, Victor, Oleg Lyashuk, Olexiy Pavlenko, Denis Velykodnyi, Andrii Hrynkiv, Sergii Lysenko, Dmytro Holub, Yuriy Vovk, Volodymyr Dzyura e Mariana Sokol. "Realization of the Logistic Approach in the International Cargo Delivery System". Communications - Scientific letters of the University of Zilina 21, n. 2 (24 maggio 2019): 3–12. http://dx.doi.org/10.26552/com.c.2019.2.3-12.

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Fierce rivalry in the transport market raises serious reassessment and implementation of new approaches to logistics companies and trade enterprises in marketing of goods. To maintain the volume of domestic sales and output to the external one, producers and trading firms are forced to expand their trade and economic relations that occur in other regions. The integration of the world economy and policy orientation of foreign trade to free trade greatly simplify the task of setting up the free trade and economic connections, but the question is how quickly and efficiently, with the least costs, it is necessary to put the goods in the right region to the customer.In modern market conditions, international container transportation of goods between Ukraine and the European Union countries has a prospect of development, as each year the number of orders in transport and logistics enterprises increases. After analyzing the status of orders, the problem has been detected and widely connected with the method of organization of container cargo delivery in international communication and the formation of rational technology of serviced. To solve this problem a method of logistic approach to the system of containers transportation has been proposed based on the cybernetic model „white box“. The initial stage of its implementation involves formation of the limitation system of input parameters and factors that are consistent with the needs of the customer firm and the company performing transportation. Ten alternative order services schemes, each of which takes into account the possible combinations of operations, has been proposed.Based on the company „Inter Trans Logistic“, which serviced the order of the company „Agricultural Holding August“ for the transportation of rape seeds, 10 tons of corn on demand and a portion of sunflower oil 20,000 liters, according to their applications for transportation, a logistic approach using a cybernetic model „white box“ has been implemented. Based on the mathematical models of changes in the total costs of the international container cargo shipping company of the customer, it has been shown that the maximum expenses are occurring in the implementation of the scheme 1 service order. In that case, the costs have been in the range of 848.72 to 7455.41 US $, according to a certain series of experiments. Based on the condition of the minimum cost function for container transportation, scheme 1 has been chosen as limiting scheme of service order against which the assessment carried out changes of the total costs in the implementation of other schemes. In percentage display according to Scheme 1, the following percentage intervals have been deducted for the reduction of sales costs: Scheme 2 - 12.70 to 34.98%; Scheme 3 - 2.93 to 12.00%; Scheme 4 - 2.06 to 10.88%; Scheme 5 - 1.69 to 4.25%; Scheme 6 - 0.87 to 3.28%; scheme7 - 0.97 to 2.58%; Scheme 8 - 1.64 to 4.45%; Scheme 9 - 2.66 to 11.77%; scheme 10 - 2.33 to 9.94%.The results of experimental studies indicate that when the proposed methodology of the logistic approach, using the „white box“ based on the company „Inter Trans Logistic“ to international container transportation of goods in relation to the application of the company „Agricultural Holding August“ for transportation, the scheme 2 sequence of transport operations has been effective. In its realization the costs for 12.70 to 34.98% has been decreased in comparison with the marginal service scheme.

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CANDY, J. V., e E. J. SULLIVAN. "MODEL-BASED SIGNAL ENHANCEMENT FOR THE HUDSON CANYON EXPERIMENT". Journal of Computational Acoustics 02, n. 03 (settembre 1994): 327–44. http://dx.doi.org/10.1142/s0218396x9400021x.

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Model-based signal processing is a well-defined methodology enabling the inclusion of environmental (propagation) models, measurement (sensor arrays) models, and noise (shipping, measurement) models into a sophisticated processing algorithm. Here we investigate the design of a space-varying, nonstationary, model-based processor (MBP) for the Hudson Canyon experiment. In this shallow water application, a state space representation of the normal mode propagation model is used. The processor is designed such that it allows in situ recursive estimation of the both the pressure field and modal functions. It is shown that the MBP can be effectively utilized to "validate" the performance of the model on noisy ocean acoustic data. In fact, a set of processors is designed, one for each source range, and the results are reasonable, implying that the propagation model with measured parameters adequately represents the data.

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Barcellona, Marco, Maurizio Simos, Marilena Greco e O. M. Faltinsen. "An Experimental Investigation on Bow Water Shipping". Journal of Ship Research 47, n. 04 (1 dicembre 2003): 327–46. http://dx.doi.org/10.5957/jsr.2003.47.4.327.

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The water on deck caused on a restrained ship model without forward speed in head waves is studied experimentally by using a transient test technique. A single water-shipping event is induced by the wave packet, and the severity of the interaction is controlled by the wave-packet steepness. Three different bow geometries are considered. Two of them are analytical hull forms, and the last is the ESSO-Osaka tanker. The models are equipped with a transparent-material deck to study the flow-field evolution by image analysis. A vertical wall is placed at a certain distance from the forward perpendicular to mimic the presence of deck structures. Velocity of the shipped water along the deck, pressure field on the deck, and horizontal impact force on the wall are measured. The main fluid-dynamic aspects of the green-water phenomenon are highlighted. For the tested cases, water shipping starts always with the free surface exceeding the freeboard, plunging onto the deck, and forming complex cavities entrapping air inside. The geometry of the air cavity depends on the hull form and the wave steepness. Then the water propagates along the deck. In general, the water front is strongly three dimensional because of the water entering along the deck contour. The interaction of the shipped water with the vertical structure consists of impact, run up-run down cycle, and backward plunging of the water onto the deck, still wetted. The evolution of the pressure field follows that of the water front. Pressure peaks are associated with the impact against the vertical wall, and by the backward plunging of the water on the deck, at the end of the run up-run down cycle of the water. It is shown that both these stages can be of importance from the structural point of view. I am sad to report that Maurizio Landrini was killed in a motorcycle accident on June 26, 2003. Maurizio was an outstanding marine hydrodynamist who had been selected as the 2003 Georg Weinblum Lecturer. He was born on March 2, 1963, and earned his Ph.D. degree in Theoretical and Applied Mechanics at the University of Rome. Except for short periods as a visiting researcher at the Ocean Engineering Laboratory, University of California, Santa Barbara, and the Department of Marine Technology, Norwegian University of Science and Technology, he worked his entire career at INSEAN, the Italian Ship Model Basin. He has authored or coauthored over 80 papers. He was a personal friend and innovative researcher with whom I have spent many hours discussing hydrodynamics. He will be greatly missed in the marine hydrodynamics community. Robert F. Beck

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Song, Xueguan, Maosen Cao, Wonhyup Shin, Wenping Cao, Sanghoon Kang e Youngchul Park. "Numerical Investigation of a Liquid-Gas Ejector Used for Shipping Ballast Water Treatment". Mathematical Problems in Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/259593.

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Shipping ballast water can have significant ecological and economic impacts on aquatic ecosystems. Currently, water ejectors are widely used in marine applications for ballast water treatment owing to their high suction capability and reliability. In this communication, an improved ballast treatment system employing a liquid-gas ejector is introduced to clear the ballast water to reduce environmental risks. Commonly, the liquid-gas ejector uses ballast water as the primary fluid and chemical ozone as the secondary fluid. In this study, high-pressure water and air, instead of ballast water and ozone, are considered through extensive numerical and experimental research. The ejector is particularly studied by a steady three-dimensional multiphase computational fluid dynamics (CFD) analysis with commercial software ANSYS-CFX 14.5. Different turbulence models (including standardk-ε, RNGk-ε, SST, andk-ω) with different grid size and bubble size are compared extensively and the experiments are carried out to validate the numerical design and optimization. This study concludes that the RNGk-εturbulence model is the most efficient and effective for the ballast water treatment system under consideration and simple change of nozzle shape can greatly improve the ejector performance under high back pressure conditions.

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Fonteinos, Michael I., Efstratios I. Tzanos e Nikolaos P. Kyrtatos. "Ship Hull Fouling Estimation Using Shipboard Measurements, Models for Resistance Components, and Shaft Torque Calculation Using Engine Model". Journal of Ship Research 61, n. 02 (1 giugno 2017): 64–74. http://dx.doi.org/10.5957/jsr.2017.61.2.64.

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This paper presents a method for hull condition estimation regarding fouling, by focusing on the increase of power demand over a period. Onboard recorded data from performance reports and noon reports of four Panamax bulk carriers identical sister ships were provided by a shipping company. In most cases, engine power onboard vessels is measured using a torque meter. Since torque measurements are generally considered of variable reliability and the required accuracy for the present study was high, the propeller shaft torque demand was calculated using an engine simulation software tuned for each specific engine and fed with recorded engine data. To distinguish the effect of fouling, wave-added resistance, air resistance, and calm water resistance were deducted from total ship resistance. Wave-added and air resistances were calculated using the STAwave-2 empirical method and Fujiwara regression formula, respectively. Calm water resistance was calculated using the FORMDATA systematic statistical series due to the lack of vessel's lines. The increase of resistance due to fouling was estimated through the increase of the Propeller Law coefficient (CPROP) and the Fouling Resistance coefficient (CFOUL), over a dry dock interval period.

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45

Zhou, Haiying. "Decisions on Technologies for Emissions Control in Port Areas under Subsidy and Low-Carbon Preferences of Customers". Mathematical Problems in Engineering 2022 (15 novembre 2022): 1–12. http://dx.doi.org/10.1155/2022/2359911.

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The emission control technologies decisions of port and shipping enterprises under subsidy and customers’ low-carbon preferences are discussed from a supply chain perspective. The game models are established under three game models (port-leader Stackelberg game, ship-leader Stackelberg game, and Nash game). The obtained results show that the impact of subsidy and low-carbon preference on demand in its pricing always is considered by the leader in the port supply chain. The profits and emissions in the Nash game are higher than that in the Stackelberg game. When subsidies and customers’ low-carbon preferences are low, the supply chain’s overall profits of using low sulfur oil are higher than that of using shore power. But the supply chain’s carbon emissions of adopting low sulfur oil are also higher than that of adopting shore power. When subsidies and low-carbon preferences of customers are high, the supply chain’s overall profits of using shore power are higher than that of using low sulfur oil. But the supply chain’s carbon emissions of adopting shore power are also higher than that of adopting low sulfur oil. When subsidy and low-carbon preference of customers are in the appropriate(medial) range, the supply chain would choose shore power to reduce emissions from the perspective of profits, and the whole carbon emissions of using shore power are lower than that of using low sulfur oil, so the regulator(government) and enterprises can achieve a win-win situation. Hence for a regulator who has to balance emission control and enterprises’ profits, implementing moderate subsidy within the appropriate range is the better strategy.

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Gao, Jianjie, Mingli Chi e Zhihui Hu. "Energy Consumption Optimization of Inland Sea Ships Based on Operation Data and Ensemble Learning". Mathematical Problems in Engineering 2022 (23 dicembre 2022): 1–13. http://dx.doi.org/10.1155/2022/9231782.

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Global warming, environmental pollution, and the soaring cost of energy consumption for ships have drawn the attention of the International Maritime Organization and the shipping industry. By reducing the energy consumption of ships, the greenhouse gas emissions and operating costs of ships can be effectively reduced simultaneously. However, current research on the ship energy consumption optimization based on operating mode is mainly focused on route and speed optimization and less on trim optimization, but ship trim is also an important factor affecting energy consumption. Therefore, this study proposed a ship trim optimization method based on operational data and ensemble learning to achieve energy savings and emission reductions for inland sea ships. First, data processing and feature selection of operational data from an inland ro-ro passenger ship were undertaken. Second, the energy consumption prediction models were established based on ensemble learning. Finally, the trim optimization model was developed by combining the energy consumption model with the best prediction performance and enumeration method. Experimental results show that compared with linear regression, neural networks, and support vector machines, ensemble learning methods have better prediction performance in energy consumption modeling, and the extra tree (ET) model has the best prediction performance. With the trim optimization, the energy consumption and carbon emissions of a ro-ro passenger ship can be reduced by 1.4641%, which is conducive to the green and low-carbon navigation of ships.

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Ndruru, Eferoni, e Sumiaty Adelina Hutabarat. "Implementasi Metode Vogelâ€™s Approximation Method Pada Pengoptimalan Biaya Pengiriman Barang Pada CV. Expres Nias". MEANS (Media Informasi Analisa dan Sistem), 25 giugno 2018, 12–15. http://dx.doi.org/10.54367/means.v3i1.219.

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Operations Research is one way of taking decisions in companies by formulating problems of daily life with mathematical models with the aim of getting optimal goals. Transportation problems are one of the problems in solving operational research problems with the aim of optimizing distribution costs of shipping goods from the first warehouse to the destination warehouse. Like the problem that is in cv. Express nias where the cost of shipping goods does not calculate the optimal cost sometimes losses and profits are not optimal. The method used in solving this problem is the method of Vernel's approximation method, this method is included with the method of transportation. The results obtained in this study are that all shipping costs for cv.express nias are optimal.

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Nguyen, Son, Peggy Shu-Ling Chen e Yuquan Du. "A methodological framework for quantitative risk analysis in container shipping operations". Maritime Business Review, 14 aprile 2022. http://dx.doi.org/10.1108/mabr-11-2021-0088.

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PurposeContainer shipping is a crucial component of the global supply chain that is affected by a large range of operational risks with high uncertainty, threatening the stability of service, manufacture, distribution and profitability of involved parties. However, quantitative risk analysis (QRA) of container shipping operational risk (CSOR) is being obstructed by the lack of a well-established theoretical structure to guide deeper research efforts. This paper proposes a methodological framework to strengthen the quality and reliability of CSOR analysis (CSORA).Design/methodology/approachFocusing on addressing uncertainties, the framework establishes a solid, overarching and updated basis for quantitative CSOR analysis. The framework consists of clearly defined elements and processes, including knowledge establishing, information gathering, aggregating multiple sources of data (social/deliberative and mathematical/statistical), calculating risk and uncertainty level, and presenting and interpreting quantified results. The framework is applied in a case study of three container shipping companies in Vietnam.FindingsVarious methodological contributions were rendered regarding CSOR characteristics, settings of analysis models, handling of uncertainties and result interpretation. The empirical study also generated valuable managerial implications regarding CSOR management policies.Originality/valueThis paper fills the gap of an updated framework for CSOR analysis considering the recent advancements of container shipping operations and risk management. The framework can be used by both practitioners as a tool for CSOR analysis and scholars as a test bench to facilitate the comparison and development of QRA models.

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Girina, Olga, e Svetlana Zhigalovskaya. "OPTIMIZATION OF THE USE OF THE PRODUCTION CAPACITY OF A SHIPYARD". Development of Management and Entrepreneurship Methods on Transport (ONMU), 2021, 89–107. http://dx.doi.org/10.31375/2226-1915-2021-2-89-107.

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The article discusses the issues of determining the production capacity of a shipyard and modeling the production process of ship repair using a systematic approach. The production capacity of the plant is understood as the maximum possible annual output in terms of the indicators and nomenclature established for the shipyard, with the full use of equipment and areas.The maximum volume of production is achieved when the structure of products is fully consistent with the structure of production resources and the structure of production assets. Improvement of management at the ship repair enterprise can be carried out in directions, including by creation of the model of production based on allocation of its most essential characteristics, used of mathematical methods of optimization. A static model is proposed to optimize the use of the shipyard production capacity, whenperforming scheduled preventive maintenance of shipping company ships in market conditions and a dynamic model of the annual plan in order to maximize the shipyard load and uniform use of its production capacity. In the performed calculations of the test case on the basis of the static model, four optimal plans with different optimization conditions were obtained: a plan for using the production capacity of theshipyard with the given initial data; plan with maximum production capacity with full use of shipyard resources; a plan for changing the solvency of the shipping company; plan for changing the terms and standards of ship repair. In all plans, the volume of repairs and the availability of resources limiting the production process are analyzed.Based on the proposed models, the following groups of factors on which the use of the production capacity of the shipyard depends have been identified:1) technical and operational parameters of shipyard units;2) demand for shipyard services in the form of volumes of planned work by type of production activity;3) standards for the use of shipyard capacities;4) the solvency of customers;5) the way of organizing the production process.The method of organizing ship repair is understood as fixing of certain resources of the shipyard units for the fulfillment of planned or additional customer orders. All factors of the first four groups affect the volume of ship repair and other indicators of the production program in termsthe actual or optimal way of organizing production.Key words: shipyard, production capacity, economic and mathematical models, analysis, grouping of factors

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Fromreide, Mads, e Alex Hansen. "Predicting Motion Patterns Using Optimal Paths". Frontiers in Physics 9 (21 giugno 2021). http://dx.doi.org/10.3389/fphy.2021.656296.

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The ability to navigate safely and efficiently through a given landscape is relevant for any intelligent moving object. Examples range from robotic science and traffic analysis, to the behavior within an ecosystem. Many objects tend to move in patterns depending on their nature. By establishing models of patterns of motion one may estimate the future motion within an area. We propose here a method for detecting regular patterns of motion by modeling the environment as an energy landscape, and locating optimal paths through it. As an example, we use maritime position Automatic Identification System (AIS) data as input to work out optimal routes between different start and end points when these are not located along the standard shipping lanes. These initial tests show that the method has potential for analyzing and determining regular patterns of motion.

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