Structural Characteristics and Evolution of a Weighted Sino-US Container Shipping Network

This study selected the Sino-US route data from the top 30 global container liner companies between December 1,2019,and December 29,2019,as the data source utilizing the complex network research methodology.It constructs a Sino-US container shipping network through voyage weighting and analyzes the essential structural characteristics to explore the network’s complex structural fea-tures.The network’s evolution is examined from three perspectives,namely,time,space,and event influence,aiming to comprehens-ively explore the network’s evolution mechanism.The results revealed that:1)the weighted Sino-US container shipping network exhib-its small-world and scale-free properties.Key hub ports in the United States include NEW YORK NY,SAVANNAH GA,LOS ANGELES CA,and OAKLAND CA,whereas SHANGHAI serving as the hub port in China.The geographical distribution of these hub ports is uneven.2)Concerning the evolution of the weighted Sino-US container shipping network,from a temporal perspective,the evolution of the regional structure of the entire Sino-US region and the Inland United States is in a stage of radiative expansion and de-velopment,with a need for further enhancement in competitiveness and development speed.The evolution of the regional structure of southern China and Europe is transitioning from the stage of radiative expansion and development to an advanced equilibrium stage.The shipping development in Northern China,the Western and Eastern United States,and Asia is undergoing significant changes but faces challenges of fierce competition and imbalances.From a spatial perspective,the rationality and effectiveness of the improved weighted Barrat-Barthelemy-Vespignani(BBV)model are confirmed through theoretical derivation.The applicability of the improved evolution model is verified by simulating the evolution of the weighted Sino-US container shipping network.From an event impact per-spective,the Corona Virus Disease 2019(COVID-19)pandemic has not fundamentally affected the spatial pattern of the weighted Sino-US container shipping network but has significantly impacted the network’s connectivity.The network lacks sufficient resilience and stability in emergency situations.3)Based on the analysis of the structural characteristics and evolution of the weighted Sino-US con-tainer shipping network,recommendations for network development are proposed from three aspects:emphasizing the development of hub ports,focusing on the balanced development of the network,and optimizing the layout of Chinese ports.

Model and algorithm for container ship stowage planning based on bin-packing problem

In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage planning problem increases due to its multi-ports nature. This problem is NP-hard problem. In order to reduce the computational complexity, the problem is decomposed into two sub-problems in this paper. First, container ship stowage problem (CSSP) is regarded as 'packing problem', ship-bays on the board of vessel are regarded as bins, the number of slots at each bay are taken as capacities of bins, and containers with different characteristics (homogeneous containers group) are treated as items packed. At this stage, there are two objective functions, one is to minimize the number of bays packed by containers and the other is to minimize the number of overstows. Secondly, containers assigned to each bays at first stage are allocate to special slot, the objective functions are to minimize the metacentric height, heel and overstows.The taboo search heuristics algorithm are used to solve the subproblem. The main focus of this paper is on the first subproblem. A case certifies the feasibility of the model and algorithm.

Line of sight waypoint guidance for a container ship based on frequency domain identification of Nomoto model of vessel

CIFER software is used to identify steering and roll dynamics of a container ship. In this software, advanced features such as the Chirp-Z transform(CZT) and composite window optimization are applied to the time history of steering and roll dynamics to extract high quality frequency responses. From the extracted frequency responses, two linear transfer functions of Nomoto model are fitted for yaw and roll dynamics of the vessel. Based on the identified Nomoto model, a PID heading controller and a Kalman filter observer are constructed. The simulation results of heading controller for line of sight(LOS) waypoint guidance show excellent tracking of pilot inputs in the presence of wave induced motions and forces.

Ship Size and Service Configuration in Container Shipping

This study analyzes the effect of ship size on the liner service configuration by establishing an economic model. The service configuration is characterized by the distance of service and the number of calling ports. A study ease is presented for illustration. At last such a conclusion is drawn that given a fixed profit, the ship size will change with the extension of service in the same direction, while the change rate of ship size is a little higher than that of the extension of service.

Corporate Social Responsibility and Shipping Supply Chain Risks

This study aims to investigate whether Corporate Social Responsibility(CSR)activities reduce supply chain disruptions by examining the impact of the Suez Canal obstruction on the Ever Given container ship in March 2021.This study conclude that the more responsible companies have higher returns and are less affected by this event than the less responsible companies;the less responsible companies have lower returns.The companies with better CSR have a lower impact on their supply chains when faced with disruptions in the supply chain.

Robust Optimization Model for Resource Allocation of Container Shipping Lines

The operating efficiency of container shipping lines depends on proper resource allocation of container shipping.A deterministic model was developed for shipping lines based on the equilibrium principle.The objective was to optimize the resource allocation for container lines considering ship size,container deployment,and slot allocation.The deterministic model was then expanded to a robust optimization model accounting for the uncertain factors,while ship size was treated as the design variable and slot allocation as the control variable.The effectiveness of the proposed model is demonstrated using a pendulum shipping line as an example.The results indicate that infeasible solutions will increase and the model robustness will be enhanced by an increased penalty coefficient and the solution robustness will be enhanced by increasing the preference coefficient.The optimization model simultaneously considers demand uncertainty,model robustness,and risk preference of the decision maker to agree better with actual practices.

High Strength Steel Plates for Large Container Ships

Heavy thickness steel plates with a good combination of strength,toughness and weldability have been demanded for building of large container ships.High strength steel plates with heavy gauge of EH36,EH40 and EH47 grades were developed by optimizing chemical compositions and TMCP process parameters.Micro alloying elements of Ti and Nb were added to the three steel grades for enhancing the strength and toughness of base plates.The strength of base plates of the EH47 grade was further enhanced with the help of the increased amount of substitutional solid solutes,such as manganese,copper,nickel,or chromium.EH36 steel plates for high heat input over 550 kJ/cm were manufactured by improving thermal stability of TiN particles for better weld heat-affected zone toughness.Thermally stabilized TiN particles effectively suppress grain growth at weld heat-affected zone,leading to better toughness.These steel plates showed excellent mechanical properties of base plates and welded joints.

Review of containership stowage plans for full routes

Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.

URANS simulations for a free-running container ship:Part 1. Turning-circle

The incompressible unsteady Reynolds-averaged Navier-Stokes(URANS)simulations are performed for a free-running container ship in maneuvering conditions:the starboard and portside turning circle simulations with 35°rudder deflection.The validation variables include trajectory,motions,and propeller performances,and the prediction shows acceptable agreements against the experimental data.During the steady-state part of the turning,the inertial forces balancing the local forces are reported to quantitatively assess the centrifugal force which appears from the force equilibrium between the rudder,propeller,and the bare-hull.The study on the local flow focuses on finding the correlations between the propeller inflow and the propeller performance to investigate the differences in propeller performances during the portside and starboard turning.The preliminary simulations,performed with the grid triplet,comprise propeller open-water,resistance,and self-propulsion simulations,from which the validation studies and the studies for the local force and the local flow are fulfilled and applied for the main simulations.Both propeller and rudder are fully discretized and controlled,mimicking the experiment.Level-set,overset approach and Mentor’s SST model are employed for the free-surface capturing,large motion prediction,and turbulence closure.

URANS simulations for a free-running container ship:Part 2. Added power

Part 2 reports the validation,local force and local flow study results for the free-running added power simulations whose conditions are the same as the self-propulsion test except for the increased propeller rotational speed and the presence of wave.When targeting the same mean Froude number in the wave condition,the propeller requires the increased propeller rotational speed for the operation at the low advance ratio due to the added resistance.The test is performed at five different wavelengths in head waves and four different headings in the oblique waves.For the validation study,the time series of the validation variables is decomposed with discrete Fourier transform to extract the harmonic values.Validation variables are global parameters,including motions,propeller thrust,and torque coefficients,added power variables,and self-propulsion factors which show reasonable agreement against the experiment results and produces a similar error from the self-propulsion simulation.The local force study shows that the added resistance mostly appears at the bow due to the bow plunging during the short head wave and resonance condition.The contributions of the gravitational force and the buoyant force are found to increase as the stern motion exceeds the bow motion during the long head wave condition.The oscillation of the propeller performances shows correlation with the first harmonic amplitude of the propeller inflow.Heave,pitch,and roll decay tests are performed prior to the main test to assess the natural frequencies of the ship.Same as Part 1,a discretized propeller is used.

Ship Fuel and Carbon Emission Estimation Utilizing Artificial Neural Network and Data Fusion Techniques

Ship energy consumption and emission prediction are the main concern of the shipping industry for ship energy efficiency management and pollution gas emission control. And they are attracting more global attention and research interests because of the increase in global shipping trade volume. As the core of maritime transportation, a large volume of data is collected around ships such as voyage data. Due to the rapid development of computational power and the widely equipped AIS device on ships, the use of maritime big data for improving and monitoring ship’s energy efficiency is becoming possible. In this paper, a fuel consumption and carbon emission model using the artificial neural network (ANN) framework is proposed by using AIS, ship machinery, and weather data. The proposed work is a complete framework including data collection, data cleaning, data clustering and model-building methodology. To obtain the suitable parameters of the model, the number of neurons, data inputs and activate functions were tested on both AIS-based data and MRV-based data for comparison. The results show that the proposed method can provide a solid prediction of ship’s fuel consumption and carbon emissions under varying weather conditions.

不同装载条件下小型渔船参数横摇的非定常RANS CFD仿真

Fishing boats have unique features that make them prone to changing loading conditions.When the boat leaves the port,the empty fish tank gradually fills up during fishing operations which may result in parametric roll(PR).This dangerous phenomenon that can lead to capsizing.The present study aims to understand better the behaviour of parametric roll in fishing boats and its relation to changing loading conditions.The study considers the effects of displacement and the GM/KM ratio on parametric roll,as well as the longitudinal flare distribution at the waterline.Two assessments to detect the parametric roll occurrence in early stage were carried out by using the level 1 assessment of parametric roll based on the Second Generation of Intact Stability criteria(SGIS)from International maritime Organisation(IMO)and the Susceptibility criteria of Parametric roll from the American Bureau of Shipping(ABS).Then,the CFD method is used to predict the amplitude of the parametric roll phenomenon.The results provide important insights to fishing vessel operators on how to manage loading conditions to maintain stability and avoid hazardous situations.By following the guidelines outlined in this study,fishing boats can operate more safely and efficiently,reducing the risk of accidents and improving the overall sustainability of the fishing industry.

Peripheral Challenge in Container Port System:A Case Study of Pearl River Delta

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe,and has led to the elaboration of several theoretical models.However,although changes in containerization growth have been taking place in the South and East Asia in recent years,particularly in China,only a few studies have fo-cused on this region.The Pearl(Zhujiang) River Delta(PRD) has a typical port system with hub and peripheral ports,and provides an excellent case for studying the Peripheral Challenge.This paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases:1) phase I:preconditions for change and phase II:initial container port development in the 1970s and early 1980s;2) phase III:diffusion,consolidation,and port concentration in the middle and late 1980s;3) phase IV:the load center in the 1990s;and(4) phase V:the Peripheral Challenge since the late 1990s.The results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port,descending from a transshipment hub of China to a regional load center of Southeast China.Furthermore,this paper explores five points that have led to the evolution of the port system in the PRD:1) competition in the regional port systems;2) different interested parties;3) shift of investment strategies of in-ternational terminal operators;4) integration of shipping networks and reorganization of carriers;and 5) cost-based competition.

A Non-geometrically Similar Model for Predicting the Wake Field of Full-scale Ships

The scale effect leads to large discrepancies between the wake fields of model-scale and actual ships, and causes differences in cavitation performance and exciting forces tests in predicting the performance of actual ships. Therefore, when test data from ship models are directly applied to predict the performance of actual ships, test results must be subjected to empirical corrections. This study proposes a method for the reverse design of the hull model. Compared to a geometrically similar hull model, the wake field generated by the modified model is closer to that of an actual ship. A non-geometrically similar model of a Korean Research Institute of Ship and Ocean Engineering （KRISO）’s container ship （KCS） was designed. Numerical simulations were performed using this model, and its results were compared with full-scale calculation results. The deformation method of getting the wake field of full-scale ships by the non-geometrically similar model is applied to the KCS successfully.

Parameters Estimation and Evaluation for the Probability Density Function of Structural Fatigue Stress of a Container Vessel

Fatigue stress measurement has been playing a significant role in the ship structural health monitoring and ship structural safety assessment. The PDF （probability density function） of the measured stress is one of the essentials for the further studyin this domain. This paper, based on the strain-stress data collected from a container ship, focuses on the spectrum feature of the ship structural fatigue stress. A general analysis procedure for ship hull health estimation was firstly demonstrated. With the guidance of this procedure, the estimation and test of the parameters for the PDF of the stress were conducted, which showed that the stress spectrums fit well with the Weibull distribution. To review the fatigue state, the PDF and distribution function of fatigue damage increment were further developed and examined. The structural healthy assessment of this vessel shown the daily relative fatigue damage increment obeys log-normal or Weibull distribution and the increment of the fatigue damage on steel box girders of the ship hull was very low. Finally, the analyzing results yielded that the girder structure of the ship hull had a very low failure probability, matching well with the actual relative low working load of the ship.

Port and Shipping Express Management: The Challenges Faced by West and Central Africa in This Century

Shipping industry has become more capital intensive, technically more demanding and subject to major global regulatory reforms. As a consequence, the number of African shipping lines has been severely reduced. International trade of the WCA countries remains weak, limited to 30% of their Gross Domestic Product (GDP). The goal of this paper is to provide a comprehensive overview of the port and shipping convey management in the WCA region, and of course to describe what has been achieved since then and what still have to be done to better its infrastructures and port community.

Spectral and statistical analysis of bow wave breaking characteristics of KCS ship

Bow wave breaking is a common phenomenon during ship navigation,especially at a high speed,involving complex physical mechanism such as interface mixing,air entrainment,and jet splashing.This study uses the delayed detached eddy simulation(DDES)turbulence model on the OpenFOAM platform to simulate flow around a KRISO Container Ship(KCS)model for a Froude number of 0.35,examining trim angles of 0°,0.5°,1°.This paper analyzes the statistical and power spectral density(PSD)characteristics of bow wave heights.The analysis shows root mean square(rms)and mean difference between top and bottom views indicate wave breaking.As the trim angle increases,peaks of rms in the bottom view become much higher than that in the top view,reaching 38%at 1°.PSD analysis reveals that resistance and wave height periods differ by no more than 5%,with small-scale structures like jetting and splashing causing non-dominant periodic and high-frequency wave height variations.

Numerical study of air cavity characteristics of bow wave breaking of KCS ship under different speeds

Ship bow wave breaking contains complex flow mechanism,which is very important for ship performance.In this study,a practical numerical simulation scheme for bow wave breaking is proposed and the scheme is applied to the simulation of bow wave breaking of KCS ship model with Fr=0.26,0.30,0.35,0.40,analyzing the impact of speed on the bow wave breaking.The results indicate that an increase in speed leads to a significant rise in viscous pressure resistance and more pronounced bow wave breaking.Moreover,it is found that the traditional wave height function in OpenFOAM is not suitable for detailed studies of bow wave breaking.This study extracts different free surfaces through top and bottom views to further analyze the free surface overturning,droplet splashing,and cavity entrainment in bow wave breaking.Additionally,the spatial and temporal distribution of cavities at Fr=0.40 is analyzed,revealing that cavity distribution is closely related to vortex structures and exhibits a periodic pulsation characteristic of approximately 12 s.

集装箱班轮联营系统协同测度方法与实证

针对集装箱班轮联营系统的协同运作绩效问题,本文提出相应协同测度方法和模型,并进行实证应用研究.结合国际航运实际,应用协同理论方法,确定集装箱班轮联营系统协同机制框架,选取班轮联营实际运作指标,构建协同测度模型和评价体系,并以协同度来度量集装箱班轮联营系统的协同状况.以典型的CKYH集装箱班轮联营系统为实证案例,对该问题进行方法和模型的验证.研究结果表明,集装箱班轮联营系统协同度体现在系统各构成部分和系统要素的相互作用中,方法和模型能够有效地测度联营系统协同状况,研究结果符合航运实际,检验了该方法和模型的有效性.

Scale effects on bow wave breaking of KCS ship model:Insights from DDES investigations

Ship bow wave breaking is a common phenomenon during navigation,involving complex multi-scale flow interactions.However,the understanding of this intense free surface flow issue is not sufficiently deep,especially regarding the lack of research on the impact of scale effects on bow wave breaking.This paper focuses on the benchmark ship model KCS and conducts numerical simulations and comparative analyses of bow wave breaking for three model scales under the condition of Fr=0.35.The numerical calculations were performed using the in-house computational fluid dynamics(CFD)solver naoe-FOAM-SJTU,which is developed on the open source platform OpenFOAM.Delayed detached eddy simulation(DDES)method is utilized to calculate the viscous flow field around the ship hull.The present method was validated through measurement data of wave profiles and wake flows obtained from model tests.Flow field results for three different scales,including bow wave profiles,vorticity at various sections,and wake distribution,were presented and analyzed.The results indicate that there is small difference in the bow wave overturning and breaking for the first two occurrences across different scales.However,considerable effects of scale are observed on the temporal and spatial variations of the free surface breaking pattern after the second overturning.The findings of this study can serve as valuable data references for the analysis of scale effects in ship bow wave breaking phenomena.