Korea Maritime Institute

This article is essentially an empirical investigation in the network analysis of inter-port traffic flows. Based on a database of vessel movements, it applies conventional techniques of network analysis to the graph of Northeast Asian liner networks in 1996 and 2006. Such an approach proves particularly helpful for analyzing the changing position of major hub ports and for revealing their respective tributary areas within the region. Despite rapid traffic growth at Chinese ports during the period under study, the latter seem to remain polarized by established hubs such as Korean ports and Hong Kong. This research reveals the strong relation between local port policies and the evolution of shipping network design.

Ship collisions are major types of maritime accidents which may involve the loss of life and significant damage to property and the environment. Although many automatic ship collision avoidance algorithms have been suggested, most of them are only applicable to a single ship-to-ship encounter situation. Also, although there exist some studies on collision avoidance for multiple agent systems, maritime traffic rules have not been systematically incorporated in the algorithms which limit their practical applicability to real maritime traffic situations. In this study, we propose a rule-compliant automatic ship collision avoidance method that can be applied not only to single ship-to ship situations, but also to multiple-ship encounter situations with consideration of prediction uncertainty. In order to select appropriate evasive actions, a symmetric role-classification criterion is proposed by refining the current maritime traffic rules, and an efficient collision avoidance algorithm based on the probabilistic velocity obstacle method is applied. To verify and demonstrate the performance and practical utility of the proposed algorithm, Monte-Carlo simulations were conducted and the results are presented in this article.

Countries throughout the world, and especially within Asia, are investing heavily in container port infrastructure in the hopes of capturing a larger share of global shipping activity for their economies. Many existing ports are emphasizing developing the capacity to serve as a hub port, building deepwater berths with large terminals to facilitate transfer of containers from feeder ships to mother ships for intercontinental transport. We develop a game-theoretic best response framework for understanding how competitor ports will respond to development at a focus port, and whether the focus port will be able to capture or defend market share by building additional capacity. We apply this model to investment and competition currently occurring between the ports of Busan and Shanghai.

approximating that of Japan and South Korea combined (>164,000 metric tons worth >$440 million). We further find ~3000 small-scale North Korean vessels fished, mostly illegally, in Russian waters. These results can inform independent oversight of transboundary fisheries and foreshadow a new era in satellite monitoring of fisheries.

Abstract Freshwater capture fisheries are globally essential for food security and aquatic biodiversity conservation. The Yangtze River Basin is the third longest and one of the most human‐influenced drainage basins worldwide. Since the founding of P. R. China in 1949, this large river system has suffered increasing human perturbation and its sustainable development is now severely challenged. Meta‐analysis showed that Yangtze River fisheries have experienced an extraordinary process of utilization–over‐exploitation–protection during the past 70 years, to an extent that other globally important rivers may never have encountered. Its fisheries appear to have collapsed over the past four decades, with yield decreasing to only 25% of an historical peak of 400,000 metric tonnes in the late 1950s. Endemic, migratory and rare fishes have been highly threatened with obvious changes in fish community structure and aquatic biodiversity. Anthropogenic activities, including impoundment of water in dams, discharge of pollutants and riverine modification for vessel navigation, have caused large decreases in fisheries yields. Projections from surplus production modelling showed potential for improvement under fishing ban scenarios, but without any prospect for full recovery to historical stock status. This study revealed that the change in fisheries resources was dominated by the social–ecological watershed system, and an integrated approach to river basin management is warranted. Better management of freshwater ecosystems to integrate food security with biodiversity conservation is urgently needed throughout the world, and the changes evident in the Yangtze River fish populations can serve as an informative global reference.

Abstract This study addresses the development of algorithms for multiple target detection and tracking in the framework of sensor fusion and its application to autonomous navigation and collision avoidance systems for the unmanned surface vehicle (USV) Aragon. To provide autonomous navigation capabilities, various perception sensors such as radar, lidar, and cameras have been mounted on the USV platform and automatic ship detection algorithms are applied to the sensor measurements. The relative position information between the USV and nearby objects is obtained to estimate the motion of the target objects in a sensor‐level tracking filter. The estimated motion information from the individual tracking filters is then combined in a central‐level fusion tracker to achieve persistent and reliable target tracking performance. For automatic ship collision avoidance, the combined track data are used as obstacle information, and appropriate collision avoidance maneuvers are designed and executed in accordance with the international regulations for preventing collisions at sea (COLREGs). In this paper, the development processes of the vehicle platform and the autonomous navigation algorithms are described, and the results of field experiments are presented and discussed.

The introduction of the maritime autonomous surface ships (MASS) accompanied by alternative fuels to the maritime industry is about to open a new era and lead to a new paradigm shift in terms of safety, security, and environmental protection. However, there are also some concerns on new technology which also can create new types of risks such as non-navigation risks and cybersecurity threats. This paper presents recent trends for developing autonomous vessels with the introduction of the latest projects around the globe. It also investigates the individual and combined impact of the MASS on regulations, technologies, and industries in response to the new paradigm shift in the maritime sector. Additionally, other key issues including safety, security, jobs and training, and legal and ethics are addressed to find a solution for an efficient, reliable, safe, and sustainable shipping in the near future. It is suggested that holistic approaches for developing the technology and regulatory framework are to be implemented, and the communication and cooperation of multiple stakeholders based on mutual understanding are vital for a successful arrival of the MASS in the maritime industry.

Dissolved oxygen (DO) is one of the critical parameters representing water quality in coastal environments. However, it is labor- and cost-intensive to maintain monitoring systems of DO since in situ measurements of DO are needed in high spatial and temporal resolution to establish proper management plans of coastal regions. In this study, we applied statistical analyses between long-term monitoring datasets and satellite remote sensing datasets in the eastern coastal region of the Yellow Sea. Pearson correlation analysis of long-term water quality monitoring datasets shows that water temperature and DO are highly correlated. Stepwise multiple regression analysis among DO and satellite-derived environmental variables shows that the in situ DO can be estimated by the combination of the present sea surface temperature (SST), the chlorophyll-a, and the SST in the month prior. The high skill score of our proposed model to derive DO is validated by two error measures, the Absolute Relative Error, 1-ARE (89.2%), and Index of Agreement, IOA (78.6%). By applying the developed model to the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) products, spatial and temporal changes in satellite-derived DO can be observed in Saemangeum offshore in the Yellow Sea. The analysis results show that there is a significant decrease in estimated DO between summer of 2003 versus 2012 indicating summer coastal deoxygenation due probably to the Saemangeum reclamation. This study shows the potential capability of satellite remote sensing in monitoring in situ DO in both high temporal and spatial resolution, which will be beneficial for effective and efficient management of coastal environments.

This paper proposes a harmonic elimination method for vibration and noise minimization of an interior-type permanent-magnet motor, achieved by alternating the distribution of the radial flux density. The minimization of vibration and noise is realized by forming optimal notches corresponding to the shape of the magnetic field on the rotor pole face. The variations in vibration are computed by a nonlinear finite element method, and the validity of the analysis and rotor shape design is confirmed by performing vibration and performance experiments.

Importance: Sudden sensorineural hearing loss (SSNHL) causes substantial disease burden for both individuals and socioeconomic aspects. The benefit of hyperbaric oxygen therapy (HBOT) in addition to standard medical therapy (MT) for idiopathic SSNHL has been unclear. Objective: To perform a systematic review and meta-analysis to compare HBOT + MT with MT alone as a treatment for patients with SSNHL. Data Sources: PubMed, Embase, and the Cochrane Database of Systematic Reviews were systematically searched up to February 2018. Study Selection: Randomized clinical trials and nonrandomized studies comparing HBOT + MT with MT alone for SSNHL treatment. Data Extraction and Synthesis: Two investigators independently screened the eligible studies, established data, and assessed quality and risk of bias. A systematic review and meta-analysis using random-effects models was conducted. Main Outcomes and Measures: The primary outcome was complete hearing recovery, and secondary outcomes were any hearing recovery and absolute hearing gain. Results: Three randomized clinical trials and 16 nonrandomized studies comparing outcomes after HBOT + MT vs MT alone in 2401 patients with SSNHL (mean age, 45.4 years; 55.3% female) were included. Pooled odds ratios (ORs) for complete hearing recovery and any hearing recovery were significantly higher in the HBOT + MT group than in the MT alone group (complete hearing recovery OR, 1.61; 95% CI, 1.05-2.44 and any hearing recovery OR, 1.43; 95% CI, 1.20-1.67). Absolute hearing gain was also significantly greater in the HBOT + MT group than in the MT alone group. The benefit of HBOT was greater in groups with severe to profound hearing loss at baseline, HBOT as a salvage treatment, and a total HBOT duration of at least 1200 minutes. Conclusions and Relevance: The addition of HBOT to standard MT is a reasonable treatment option for SSNHL, particularly for those patients with severe to profound hearing loss at baseline and those who undergo HBOT as a salvage treatment with a prolonged duration. Optimal criteria for patient selection and a standardized regimen for HBOT should be applied in routine practice, with future trials to investigate maximal treatment benefit.

The European Union (EU), which has led international discussions on global warming, officially announced its plan for the Carbon Border Adjustment Mechanism (CBAM) in July 2021. Many existing studies have indicated the CBAM will curtail greenhouse gases, and will subsequently be positive in terms of reducing global warming. However, serious legal issues and trade disputes are expected in terms of the compatibility of the CBAM with the trade rules of the General Agreement on Tariffs and Trade (GATT). Contrary to the EU’s explanation, the international community has a strong view of CBAM as a new trade barrier under the guise of preventing global warming. Above all, this is because it is an arbitrary measure by the EU and not the one that has been internationally agreed upon. Therefore, this paper tries to identify the pitfalls and estimate the global cost of CBAM, arguing that the mechanism is not in line with international trade rules, and that many countries will not sit back and suffer from it. The world economy will inevitably face a vicious cycle of trade retaliation. The CBAM will drive up trade costs and cause another trade distortion. While the goal of preventing climate change is good, the CBAM scheme is too costly for the world economy.

Abstract Vegetation can protect communities by reducing nearshore wave height and altering sediment transport processes. However, quantitative approaches for evaluating the coastal protection services, or benefits, supplied by vegetation to people in a wide range of coastal environments are lacking. To begin to fill this knowledge gap, we propose an integrated modeling approach for quantifying how vegetation modifies nearshore processes—including the attenuation of wave height, mean and total water level—and reduces shoreline erosion during storms. We apply the model to idealized seagrass‐sand and mangrove‐mud cases, and illustrate its potential by quantifying how those habitats reduce water levels and sediment loss beyond what would be observed in the absence of vegetation. The integrated modeling approach provides an efficient way to quantify the coastal protection services supplied by vegetation and highlights specific research needs for improved representations of the ways in which vegetation modifies wave‐induced processes.

This paper proposes a hybrid volume-of-fluid (VOF) level-set method for simulating incompressible two-phase flows. Motion of the free surface is represented by a VOF algorithm that uses high resolution differencing schemes to algebraically preserve both the sharpness of interface and the boundedness of volume fraction. The VOF method is specifically based on a simple order high resolution scheme lower than that of a comparable method, but still leading to a nearly equivalent order of accuracy. Retaining the mass conservation property, the hybrid algorithm couples the proposed VOF method with a level-set distancing algorithm in an implicit manner when the normal and the curvature of the interface need to be accurate for consideration of surface tension. For practical purposes, it is developed to be efficiently and easily extensible to three-dimensional applications with a minor implementation complexity. The accuracy and convergence properties of the method are verified through a wide range of tests: advection of rigid interfaces of different shapes, a three-dimensional air bubble's rising in viscous liquids, a two-dimensional dam-break, and a three-dimensional dam-break over an obstacle mounted on the bottom of a tank. The standard advection tests show that the volume advection algorithm is comparable in accuracy with geometric interface reconstruction algorithms of higher accuracy than other interface capturing-based methods found in the literature. The numerical results for the remainder of tests show a good agreement with other numerical solutions or available experimental data. Copyright © 2009 John Wiley & Sons, Ltd.

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results.

This research was focused on a comparative analysis of using LNG as a marine fuel with a conventional marine gas oil (MGO) from an environmental point of view. A case study was performed using a 50K bulk carrier engaged in domestic services in South Korea. Considering the energy exporting market for South Korea, the fuel supply chain was designed with the two largest suppliers: Middle East (LNG-Qatar/MGO-Saudi Arabia) and U.S. The life cycle of each fuel type was categorized into three stages: Well-to-Tank (WtT), Tank-to-Wake (TtW), and Well-to-Wake (WtW). With the process modelling, the environmental impact of each stage was analyzed based on the five environmental impact categorizes: Global Warming Potential (GWP), Acidification Potential (AP), Photochemical Potential (POCP), Eutrophication Potential (EP) and Particulate Matter (PM). Analysis results reveal that emission levels for the LNG cases are significantly lower than the MGO cases in all potential impact categories. Particularly, Case 1 (LNG import to Korea from Qatar) is identified as the best option as producing the lowest emission levels per 1.0 × 107 MJ of fuel consumption: 977 tonnages of CO2 equivalent (for GWP), 1.76 tonnages of SO2 equivalent (for AP), 1.18 tonnages of N equivalent (for EP), 4.28 tonnages of NMVOC equivalent (for POCP) and 26 kg of PM 2.5 equivalent (for PM). On the other hand, the results also point out that the selection of the fuel supply routes could be an important factor contributing to emission levels since longer distances for freight transportation result in more emissions. It is worth noting that the life cycle assessment can offer us better understanding of holistic emission levels contributed by marine fuels from the cradle to the grave, which are highly believed to remedy the shortcomings of current marine emission indicators.

This paper examines the optimal size for the Gamman Container Terminal in Pusan, Korea, in terms of berths and quay cranes. Computer simulation analyses were performed with four scenarios, representing different operational patterns. The results reveal that sharing quay cranes with adjacent berths can increase productivity, and that the more berths per operator, the higher the productivity achieved. Based on these results, container terminal development and operation policy implications are considered.

Global warming and climate change haves brought a new issue in the Arctic sea. Therefore, we can now explore new shipping routes through the Arctic Ocean instead of the existing commercial route. In particular, the Northern Sea Route (NSR) is one of the feasible shipping routes and, has provided tremendous shipping benefits. If the NSR becomes commercialized, we will be able to save about 5,000 nautical miles in distance and sailing time. In this study, we will emphasize some of the important results on the possibility of commercializing the shipping route in the Arctic. The NSR may bring positive economic effects in terms of shipping distance and time. For example, when utilizing the NSR, the maximum cargo traffic between Asia and Europe is expected to be around 46 million TEU. However, we also need to consider an expensive passage fee that is currently imposed by Russia. In conclusion, we maintain our efforts to protect the environment in the Arctic, in terms of logistics, and we need to explore every possible avenue to bring possible economic benefits to the North Pacific countries.

The member states of International Maritime Organization (IMO) have been leading in and enforcing the use of automatic identification systems (AIS) in the analysis of ship-to-ship collisions, vessel monitoring, and maritime traffic management offshore. This study will help non-federal stakeholders understand the AIS data and contribute to future research by assessing difficulties and improving access to data and applications. This study introduces the basics of AIS materials, shared channels, and currently developed applications, and discusses areas where they can be incorporated in the future. The literature revealed that using AIS data will be beneficial to the public as well as to business and public agencies.

Marine debris, such as derelict fishing gear, bottles, plastics, and Styrofoam, remain in the sea almost in perpetuity and harm the marine environment. Some marine debris is transboundary, making it a controversial issue on an international scale. With industrialization, population growth, and dense activity in coastal areas, large quantities of marine debris are generated, harming the marine environment and causing a large number of maritime accidents in Korea. Most of the coastal countries in the world are in a similar situation. The challenges to managing marine debris in Korea are shared with the international marine community. Keywords: environmental impactmarine debrismarine debris managementmarine environment The author thanks the editor and two anonymous reviewers for their thoughtful comments on the manuscript. The author also thanks Karen Hae-Myung Hyun at Department of Marine Affairs, University of Rhode Island for editing earlier versions of this manuscript.

Blue carbon science requires the estimates of organic carbon stock and sequestration rate; however, holistic data analysis remains limited in South Korea. The present study reports current organic carbon stocks and sequestration rates in the coastal areas of West Sea, South Sea, and East Sea of South Korea, encompassing entire intertidal areas using long-term field survey combined with remote sensing technology. Twenty-one intertidal flats were targeted across seven provinces (Gyeonggi, Chungnam, Jeonbuk, Jeonnam, Gyeongnam, Gyeongbuk, Gangwon). Out of the evaluated environmental parameters, mud content represented a significant factor controlling sedimentary organic carbon stocks across target areas, and was significantly positively correlated to the total organic carbon (p < 0.05). Organic carbon stocks measured in salt marshes (i.e., upper intertidal zone) reflected the high carbon fixation capacity of halophytes through primary production. Sediment textural type was classified using analysis of remotely sensed imagery, and was closely correlated to field-based classification data (p < 0.05). Using field and remote sensing results, we estimated total organic carbon stocks (13,142,149 Mg C) and sequestration rates (71,383 Mg C yr−1) in the tidal flats of South Korea. This study presents the first report on blue carbon potential in the Korean tidal flats, providing baseline information on the carbon dynamics of intertidal sediments in this region and, potentially, elsewhere.