PLOS ONE: [sortOrder=DATE_NEWEST_FIRST, sort=Date, newest first, q=subject:"Marine engineering"]PLOShttps://journals.plos.org/plosone/webmaster@plos.orgaccelerating the publication of peer-reviewed sciencehttps://journals.plos.org/plosone/search/feed/atom?sortOrder=DATE_NEWEST_FIRST&unformattedQuery=subject:%22Marine+engineering%22&sort=Date,+newest+firstAll PLOS articles are Open Access.https://journals.plos.org/plosone/resource/img/favicon.icohttps://journals.plos.org/plosone/resource/img/favicon.ico2024-03-29T12:22:18ZEnhancing shipyard transportation efficiency through dynamic scheduling using digital twin technologyMiaomiao SunChengji LiangDaofang Chang10.1371/journal.pone.02970692024-02-29T14:00:00Z2024-02-29T14:00:00Z<p>by Miaomiao Sun, Chengji Liang, Daofang Chang</p>
Uncertainties, such as road restrictions at shipyards and the irregular shape of blocks, pose challenges for transporter scheduling. Efficient scheduling of multiple transporters is critical to improving transportation efficiency. The digital twin (DT) technology offers numerous benefits, enabling interactions between the virtual and real worlds, real-time mapping, and dynamic performance evaluation. Based on DT technology, this study proposes a dynamic scheduling approach for cooperative transportation utilizing multiple transporters. The scheduling problem for multiple transporters is addressed and modeled in this study, considering factors such as block size and transporter loading. To solve this problem, a framework of DT-based multiple transporters system is established in a virtual environment. By inputting block information into this system, a solution is generated using transporter scheduling rules and interference detection methods. Experimental comparisons are conducted in this paper, exploring various scenarios with different number of tasks and the application of DT. The results demonstrate that the proposed approach effectively enhances transportation efficiency and improves ship construction efficiency. Hence, this study expands the application of DT technology in dynamic scheduling of transportation in shipyards and provides new ideas for shipbuilding company managers.A study of user switching intention for ERP systems based on push-pull-mooring model: Focusing on the important role of information quality for usersHyeon JoDo-Hyung Park10.1371/journal.pone.02894832023-11-09T14:00:00Z2023-11-09T14:00:00Z<p>by Hyeon Jo, Do-Hyung Park</p>
Enterprise resource planning (ERP) systems have become indispensable within companies due to their substantial functions and benefits. With a plethora of ERP systems available in the market, management is offered a broad array of options. This paper endeavours to identify the determinants influencing the switching intention of ERP users. Utilizing a conceptual model that adapts the push-pull-mooring paradigm, we seek to construct a formation mechanism of switching intention. Through structural equation modeling conducted on data collected from 236 users, our study uncovers several key findings. The study indicates that system quality, information quality, and top management support exert considerable influence on switching intention via satisfaction. Notably, we found that user satisfaction has a negative impact on switching intention. Our analysis also reveals that alternative attractiveness significantly determines switching intention. These findings provide valuable insights for organizations and ERP vendors to better understand user behaviour and to strategically manage user retention and switching decisions.Marine ship instance segmentation by deep neural networks using a global and local attention (GALA) mechanismZequn SunChunning MengTao HuangZhiqing ZhangShengjiang Chang10.1371/journal.pone.02792482023-02-24T14:00:00Z2023-02-24T14:00:00Z<p>by Zequn Sun, Chunning Meng, Tao Huang, Zhiqing Zhang, Shengjiang Chang</p>
Marine ships are the transport vehicle in the ocean and instance segmentation of marine ships is an accurate and efficient analysis approach to achieve a quantitative understanding of marine ships, for example, their relative locations to other ships or obstacles. This relative spatial information is crucial for developing unmanned ships to avoid crashing. Visible light imaging, e.g. using our smartphones, is an efficient way to obtain images of marine ships, however, so far there is a lack of suitable open-source visible light datasets of marine ships, which could potentially slow down the development of unmanned ships. To address the problem of insufficient datasets, here we built two instance segmentation visible light datasets of marine ships, MariBoats and MariBoatsSubclass, which could facilitate the current research on instance segmentation of marine ships. Moreover, we applied several existing instance segmentation algorithms based on neural networks to analyze our datasets, but their performances were not satisfactory. To improve the segmentation performance of the existing models on our datasets, we proposed a global and local attention mechanism for neural network models to retain both the global location and semantic information of marine ships, resulting in an average segmentation improvement by 4.3% in terms of mean average precision. Therefore, the presented new datasets and the new attention mechanism will greatly advance the marine ship relevant research and applications.Numerical investigation of the effect of spanwise length and mesh density on flow around cylinder at Re = 3900 using LES modelHaider AliNiaz Bahadur KhanMuhammad JameelAzam KhanMuhammad SajidAdnan MunirA. El-Sayed AhmedKhalid Abdulkhaliq M. AlharbiAhmed M. Galal10.1371/journal.pone.02660652022-04-08T14:00:00Z2022-04-08T14:00:00Z<p>by Haider Ali, Niaz Bahadur Khan, Muhammad Jameel, Azam Khan, Muhammad Sajid, Adnan Munir, A. El-Sayed Ahmed, Khalid Abdulkhaliq M. Alharbi, Ahmed M. Galal</p>
Flow around circular cylinder has been extensively studied by researchers for several decades due to its wide range of engineering applications such as in heat exchangers, marine cables, high rise building, chimneys, and offshore structures. The lack of clear understanding of the unsteady flow dynamics in the wake of circular cylinder and high computational cost are still an area of high interest amongst the researchers. The aim of the current study is to investigate the effect of variation in spanwise length and grid resolution in the spanwise direction on the recirculation length, separation angle of wake flow by performing large eddy simulations (LES). This study is an extension to previous work by Khan, NB et al, 2019 in which the spanwise length is restricted to 4D only. In current study, the spanwise length is changed from 0.5D to 8D where D is diameter of cylinder and mesh resolution in the spanwise direction is changed from 1 to 80 elements in the present study. The recirculation length, separation angle and wake characteristics are analyzed in detail. It is concluded that after getting optimize spanwise length, mesh resolution in the spanwise direction is the only parameter contributing toward better result.Scheduling management and optimization analysis of intermediate products transfer in a shipyard for cruise shipsJiajie LiuJingbo YinRafi Ullah Khan10.1371/journal.pone.02650472022-03-22T14:00:00Z2022-03-22T14:00:00Z<p>by Jiajie Liu, Jingbo Yin, Rafi Ullah Khan</p>
Shipbuilding is a complex and large-scale operation involving many intermediate products (blocks) and the frequent transfer of blocks among workshops and stockyards. The reasonable use of methods to complete the transfer scheduling of intermediate products is of great importance. In this paper, the blocks and the flat transporters are the research objects. Based on organizing the various logistical processes for blocks and the circulation process in the shipyard, we established a model that takes the task time window and other factors as constraints, and minimizes the sum of delay time and no-load time of flat transporters while satisfying the punctuality of scheduling tasks. Three conclusions are reached: (1)The flat transporter utilization rate is inversely related to the value of the objective function. The smaller the value of the objective function, the more the usage rate of a particular one (2) loading is the biggest obstacle to the overall working time of flat transporters, and a simple optimization model cannot solve this problem; and (3) based on the optimization model, the load efficiency of flat transporters can be improved, and the delivery time can be reduced.An online identification approach for ship domain model based on AIS dataWei ZhouJian ZhengYingjie Xiao10.1371/journal.pone.02652662022-03-10T14:00:00Z2022-03-10T14:00:00Z<p>by Wei Zhou, Jian Zheng, Yingjie Xiao</p>
As an important basis of navigation safety decisions, ship domains have always been a pilot concern. In the past, model parameters were usually obtained from statistics of massive historical cumulative data, but the results were mostly historical analysis and static data, which obviously could not meet the needs of pilots who wish to master the ship domain in real time. To obtain and update the ship domain parameter online in time and meet the real-time needs of maritime applications, this paper obtains CRI as the weight coefficient-based PSO-LSSVM method and proposes to use short-term AIS data accumulation through the risk-weighted least squares method online rolling identification method, which can filter nonhazardous targets and improve the identification accuracy and real-time performance of nonlinear models in the ship domain. The experimental examples show that the method can generate the ship domain dynamically in real time. At the same time, the method can be used to study the dynamic evolution characteristics of the ship domain over the course of navigation, which provides a reference for navigation safety decisions and the analysis of ship navigation behavior.<i>Batavia</i> shipwreck timbers reveal a key to Dutch success in 17th-century world tradeAoife DalyMarta Domínguez-DelmásWendy van Duivenvoorde10.1371/journal.pone.02593912021-10-29T14:00:00Z2021-10-29T14:00:00Z<p>by Aoife Daly, Marta Domínguez-Delmás, Wendy van Duivenvoorde</p>
Ocean-going ships were key to rising maritime economies of the Early Modern period, and understanding how they were built is critical to grasp the challenges faced by shipwrights and merchant seafarers. Shipwreck timbers hold material evidence of the dynamic interplay of wood supplies, craftmanship, and evolving ship designs that helped shape the Early Modern world. Here we present the results of dendroarchaeological research carried out on <i>Batavia</i>’s wreck timbers, currently on display at the Western Australian Shipwrecks Museum in Fremantle. Built in Amsterdam in 1628 CE and wrecked on its maiden voyage in June 1629 CE in Western Australian waters, <i>Batavia</i> epitomises Dutch East India Company (<i>Verenigde Oostindische Compagnie</i>, or VOC) shipbuilding. In the 17th century, the VOC grew to become the first multinational trading enterprise, prompting the rise of the stock market and modern capitalism. Oak (<i>Quercus</i> sp.) was the preferred material for shipbuilding in northern and western Europe, and maritime nations struggled to ensure sufficient supplies to meet their needs and sustain their ever-growing mercantile fleets and networks. Our research illustrates the compatibility of dendrochronological studies with musealisation of shipwreck assemblages, and the results demonstrate that the VOC successfully coped with timber shortages in the early 17th century through diversification of timber sources (mainly Baltic region, Lübeck hinterland in northern Germany, and Lower Saxony in northwest Germany), allocation of sourcing regions to specific timber products (hull planks from the Baltic and Lübeck, framing elements from Lower Saxony), and skillful woodworking craftmanship (sapwood was removed from all timber elements). These strategies, combined with an innovative hull design and the use of wind-powered sawmills, allowed the Dutch to produce unprecedented numbers of ocean-going ships for long-distance voyaging and interregional trade in Asia, proving key to their success in 17<sup>th</sup>-century world trade.The design of the arrangement of evacuation routes on a passenger ship using the method of genetic algorithmsDorota Łozowicka10.1371/journal.pone.02559932021-08-09T14:00:00Z2021-08-09T14:00:00Z<p>by Dorota Łozowicka</p>
The article concerns the problem of evacuation from passenger ships. It is important because it has not yet been possible to eliminate all the hazards associated with sea travel. In this paper, a concept of a method allowing to determine the arrangement of evacuation routes, for which evacuation time would be minimal, was presented. The genetic algorithm method was used in the calculations, and an original method of coding the considered problem was proposed. Sample calculations were performed to verify the correctness of the proposed algorithm. The results of applying the developed method to calculate the evacuation time on a real passenger ship are presented.Which ship-integrated power system enterprises are more competitive from the perspective of patent?Danyang LiXinlai Li10.1371/journal.pone.02520202021-05-24T14:00:00Z2021-05-24T14:00:00Z<p>by Danyang Li, Xinlai Li</p>
By analyzing the relevant patent data, the technological competitiveness of enterprises can be objectively evaluated, and the research and development priorities and the technological advantages and disadvantages of each enterprise in the same field can be compared and analyzed. It is considered to be helpful in judging the patent strategy, innovation ability, and the innovation level of enterprises, which is of great practical significance. Based on the field of the ship-integrated power system as an example, considering the Derwent patent holder code, draw the integrated technical strength of ships in the field of the distribution power system; using the ideas of the Boston matrix to measure the field has the competitive advantage of enterprises; by using the social network analysis method for each enterprise, the core technology of mining, based on the S curve of the technology life cycle, analyzes the enterprise concentration each time in order to predict the future trend of development. It can be found that China Shipbuilding Industry Corporation has the largest number of patents, followed by Fuji Electric Co. Ltd, International General Electric, Daewoo shipbuilding ocean engineering Co. Ltd and so on. Considering the patent quantity and the patent quality, the dominant and productive enterprises in this field can be distinguished. The ship-integrated power system and its related core technologies have been rapidly growing at present. The related technology patents will increase rapidly in the next few years, and more and more enterprises will participate in this field.Measuring the global impact of destructive and illegal fishing on maritime piracy: A spatial analysisRaj M. DesaiGeorge E. Shambaugh10.1371/journal.pone.02468352021-02-24T14:00:00Z2021-02-24T14:00:00Z<p>by Raj M. Desai, George E. Shambaugh</p>
Maritime piracy constitutes a major threat to global shipping and international trade. We argue that fishers turn to piracy to smooth expected income losses and to deter illegal foreign fishing fleets. Previous investigations have generally focused on cross-national determinants of the incidence of piracy in territorial waters. These investigations neglect piracy in international waters and ignore its spatial dependence, whereby pirate attacks cluster in certain locations due to neighborhood and spillover effects. We conduct a geographically disaggregated analysis using geo-referenced data of piracy and its covariates between 2005 and 2014. We demonstrate that the incidence of piracy in a particular location is associated with higher catch volumes from high-bycatch and habitat-destroying fishing, even when controlling for conditions in proximate coastal areas. We find, additionally, that illegal, unreported, and unregulated fishing exerts an especially pronounced effect on piracy. These findings highlight the need for anti-piracy solutions beyond enforcement to include the policing of fishing practices that are illegal or are perceived by local fishers in vulnerable coastal areas to be harmful to small-scale fishing economies.Physical influences on seafarers are different during their voyage episodes of port stay, river passage and sea passage: A maritime field studyMarcus OldenburgChristian FeltenJörg HedtmannHans-Joachim Jensen10.1371/journal.pone.02313092020-04-08T14:00:00Z2020-04-08T14:00:00Z<p>by Marcus Oldenburg, Christian Felten, Jörg Hedtmann, Hans-Joachim Jensen</p>
Introduction <p>During a sea voyage, crew members of vessels are permanently exposed to physical stress caused by noise, vibration and heat. This study aims to describe the extent of the physical influences on board container ships and the resulting stress.</p> Methods <p>Up to four scientific investigators accompanied six sea voyages on container ships under German management. Workplace and person-related measurements for noise, vibration and climatic parameters were carried out on the vessels during the three different voyage episodes (port stay, river passage and sea passage).</p> Results <p>The interviewed seafarers reported, in decreasing order, the level of psychological stress due to vibration (80.6%), noise (71.8%) and, much less, heat (45.7%) in the workplace.In terms of workplace-related physical measurements, the highest noise levels were found in the engine room (104 dB (A)), in the workshop (81 dB (A)) and on deck (77 dB (A)), irrespective of the voyage episode. Some noise measurements in the recreational area revealed levels above the threshold. All measured 180 vibration values were below the relevant threshold limits—with the highest values in the engine room (62 mm/s<sup>2</sup>), followed by the workshop (37 mm/s<sup>2</sup>) and the engine control room (34 mm/s<sup>2</sup>). In terms of thermal comfort, none of the measured climatic parameters differed significantly between the voyage episodes. According to the person-related physical measurements, the noise exposure was particularly pronounced among the engine room personnel with an average noise level of 96 dB (A) (often during cleaning, painting and repair work). In contrast, the deck crew and nautical officers were respectively exposed to an average level of 83 dB (A) and 77 dB (A) at work.</p> Discussion <p>A relevant stress level due to physical loads was detectable in the present study. As ship crews are exposed to the physical influences on board for 7 days a week over several months, further research is recommended to assess the long-term health effects for seafarers.</p>Mining ship deficiency correlations from historical port state control (PSC) inspection dataJunjie FuXinqiang ChenShubo WuChaojian ShiHuafeng WuJiansen ZhaoPengwen Xiong10.1371/journal.pone.02292112020-02-21T14:00:00Z2020-02-21T14:00:00Z<p>by Junjie Fu, Xinqiang Chen, Shubo Wu, Chaojian Shi, Huafeng Wu, Jiansen Zhao, Pengwen Xiong</p>
Early warning on the ship deficiency is crucial for enhancing maritime safety, improving maritime traffic efficiency, reducing ship fuel consumption, etc. Previous studies focused on the ship deficiency exploration by mining the relationships between the ship physical deficiencies and the port state control (PSC) inspection results with statistical models. Less attention was paid to discovering the correlation rules among various parent ship deficiencies and subcategories. To address the issue, we proposed an improved Apriori model to explore the intrinsic mutual correlations among the ship deficiencies from the PSC inspection dataset. Four typical ship property indicators (i.e., ship type, age, deadweight and gross tonnage) were introduced to analyze the correlations for the ship parent deficiency categories and subcategories. The findings of our research can provide basic guidelines for PSC inspections to improve the ship inspection efficiency and maritime safety.Design ride control system using two stern flaps based 3 DOF motion modeling for wave piercing catamarans with beam seasLihua LiangJia YuanSongtao ZhangHongyu ShiYanwen LiuPeng Zhao10.1371/journal.pone.02144002019-03-25T14:00:00Z2019-03-25T14:00:00Z<p>by Lihua Liang, Jia Yuan, Songtao Zhang, Hongyu Shi, Yanwen Liu, Peng Zhao</p>
A ride control system (RCS) based linear quadratic regulator (LQR) and genetic algorithm (GA) design is presented, to reduce the heave, roll and pitch motion (three degrees of freedom motion (3 DOF motion)) of the wave piercing catamarans (WPC) in beam waves. A detailed 3 DOF ride control model which consists of the coupling and decoupling relationships between longitudinal and transverse motion is proposed for the WPC vessel. And the complex hydrodynamic coefficients and disturbances induced by beam waves are analyzed. Moreover, two stern flaps are designed for the system in the way of alternate flapping. In the controller design, the LQR method based on GA method is adopted to reduce the 3 DOF motion of the ship. Depending on the robust search mechanism and global optimum of GA, weighting parameters can be obtained to calculate the desired gain. Finally, the motion reduction and motion sickness incidence (MSI) results demonstrate the feasibility and effectiveness of the proposed controller, and the comfort of passengers and crews can also be improved.Research on shipborne aided navigation system based on enhanced traffic environment perceptionYaotian FanLiwen HuangDan JiangXianzhang Xu10.1371/journal.pone.02064022018-10-31T14:00:00Z2018-10-31T14:00:00Z<p>by Yaotian Fan, Liwen Huang, Dan Jiang, Xianzhang Xu</p>
The traditional shipborne navigation system uses a two-dimensional electronic chart as a platform to integrate and control a variety of electronic navigation equipment information. It cannot intuitively restore the actual traffic environment or fundamentally improve the perception ability of the crew in poor visibility conditions. This paper proposes integrating three-dimensional simulations and real ship driving systems and presents research on “virtual–real” and “dynamic–static” ship navigation technology and equipment. In the proposed method, the hydrologic factors, topographic features, waterways, traffic dynamics, and ship driving information are effectively integrated, with a focus on achieving key advancements such as the integration of simulations and real ship driving as well as multi-source information fusion. A multi-angle, all-around, multi-level visual display for water traffic environments in poor visibility conditions is provided to enhance the ability of crews to perceive their traffic environments and thereby to provide auxiliary navigation for ships in complex weather conditions.Hierarchical and coupling model of factors influencing vessel traffic flowZhao LiuJingxian LiuHuanhuan LiZongzhi LiZhirong TanRyan Wen LiuYi Liu10.1371/journal.pone.01758402017-04-17T14:00:00Z2017-04-17T14:00:00Z<p>by Zhao Liu, Jingxian Liu, Huanhuan Li, Zongzhi Li, Zhirong Tan, Ryan Wen Liu, Yi Liu</p>
Understanding the characteristics of vessel traffic flow is crucial in maintaining navigation safety, efficiency, and overall waterway transportation management. Factors influencing vessel traffic flow possess diverse features such as hierarchy, uncertainty, nonlinearity, complexity, and interdependency. To reveal the impact mechanism of the factors influencing vessel traffic flow, a hierarchical model and a coupling model are proposed in this study based on the interpretative structural modeling method. The hierarchical model explains the hierarchies and relationships of the factors using a graph. The coupling model provides a quantitative method that explores interaction effects of factors using a coupling coefficient. The coupling coefficient is obtained by determining the quantitative indicators of the factors and their weights. Thereafter, the data obtained from Port of Tianjin is used to verify the proposed coupling model. The results show that the hierarchical model of the factors influencing vessel traffic flow can explain the level, structure, and interaction effect of the factors; the coupling model is efficient in analyzing factors influencing traffic volumes. The proposed method can be used for analyzing increases in vessel traffic flow in waterway transportation system.