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A Study on the Distance Error Correction of Maritime Object Detection System (해상물체탐지시스템 거리오차 보정에 관한 연구)

  • Byung-Sun Kang;Chang-Hyun Jung
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.2
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    • pp.139-146
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    • 2023
  • Maritime object detection systems, which detects small maritime obstacles such as fish farm buoys and visualizes distance and direction, is equipped with a 3-axis gimbal to compensate for errors caused by hull motion, but there is a limit to distance error corrections necessitated by the vertical movement of the camera and the maritime object due to wave motions. Therefore, in this study, the distance error of maritime object detection systems caused by the movement of the water surface according to the external environment is analyzed and corrected using average filter and moving average filter. Random numbers following a Gaussian standard normal distribution were added to or subtracted from the image coordinates to reproduce the rise or fall of the buoy under irregular waves. The distance calculated according to the change of image coordinates, the predicted distance through the average filter and the moving average filter, and the actual distance measured by laser distance meter were compared. In phases 1 and 2, the error rate increased to a maximum of 98.5% due to the changes of image coordinates due to irregular waves, but the error rate decreased to 16.3% with the moving average filter. This error correction capability was better than with the average filter, but there was a limit due to failure to respond to the distance change. Therefore, it is considered that use of the moving average filter to correct the distance error of the maritime object detection system will enhance responses to the real-time distance change and greatly improve the error rate.

A Study on Forecasting Manpower Demand for Smart Shipping and Port Logistics (스마트 해운항만물류 인력 수요 예측에 관한 연구)

  • Sang-Hoon Shin;Yong-John Shin
    • Journal of Navigation and Port Research
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    • v.47 no.3
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    • pp.155-166
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    • 2023
  • Trend analysis and time series analysis were conducted to predict the demand of manpower under the smartization of shipping and port logistics with transportation survey data of Statistic Korea during the period from 2000 to 2020 and Statistical Yearbook data of Korean Seafarers from 2004 to 2021. A linear regression model was adopted since the validity of the model was evaluated as the highest in forecasting manpower demand in the shipping and port logistics industry. As a result of forecasting the demand of manpower in autonomous ship, remote ship management, smart shipping business, smart port, smart warehouse, and port logistics service from 2021 to 2035, the demand for smart shipping and port logistics personnel was predicted to increase to 8,953 in 2023, 20,688 in 2030, and 26,557 in 2035. This study aimed to increase the predictability of manpower demand through objective estimation analysis, which has been rarely conducted in the smart shipping and port logistics industry. Finally, the result of this research may help establish future strategies for human resource development for professionals in smart shipping and port logistics by utilizing the demand forecasting model described in this paper.

Study on Improving Maritime English Proficiency Through the Use of a Maritime English Platform (해사영어 플랫폼을 활용한 표준해사영어 실력 향상에 관한 연구)

  • Jin Ki Seor;Young-soo Park;Dongsu Shin;Dae Won Kim
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.7
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    • pp.930-938
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    • 2023
  • Maritime English is a specialized language system designed for ship operations, maritime safety, and external and internal communication onboard. According to the International Maritime Organization's (IMO) International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW), it is imperative that navigational officers engaged in international voyages have a thorough understanding of Maritime English including the use of Standard Marine Communication Phrases (SMCP). This study measured students' proficiency in Maritime English using a learning and testing platform that includes voice recognition, translation, and word entry tasks to evaluate the resulting improvement in Maritime English exam scores. Furthermore, the study aimed to investigate the level of platform use needed for cadets to qualify as junior navigators. The experiment began by examining the correlation between students' overall English skills and their proficiency in SMCP through an initial test, followed by the evaluation of improvements in their scores and changes in exam duration during the mid-term and final exams. The initial test revealed a significant dif erence in Maritime English test scores among groups based on individual factors, such as TOEIC scores and self-assessment of English ability, and both the mid-term and final tests confirmed substantial score improvements for the group using the platform. This study confirmed the efficacy of a learning platform that could be extensively applied in maritime education and potentially expanded beyond the scope of Maritime English education in the future.

Evaluation of Structural Performance of 3D Printed Composite Rudder according to Internal Topology Shape (내부 위상 형상에 따른 3D 프린트 복합재 방향타의 구조 성능 평가)

  • Young-Jae Cho;Hyoung-Seock Seo;Hui-Seung Park
    • Composites Research
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    • v.36 no.6
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    • pp.454-460
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    • 2023
  • Recently, regulations on greenhouse gas emissions have been strengthened, and the International Maritime Organization (IMO) has been strengthening greenhouse gas regulations with a goal of net 'zero' emissions by 2050. In addition, in the shipbuilding/offshore sector, it is important to reduce operating costs, such as improving propulsion efficiency and lightening structures. In this regard, research is currently being conducted on topology optimization using 3D printed composite materials to satisfy structural lightness and high rigidity. In this study, three topology shapes (hexagonal, square, and triangular) were applied to the interior of a rudder, a ship structure, using 3D printed composite materials. Structural analysis was performed to determine the appropriate shape for the rudder. CFD analysis was performed at 10° intervals from 0° to 30° for each rudder angle under the condition of 8 knots, and the load conditions were set based on the CFD analysis results. As a result of the structural analysis considering the internal topology shape of the rudder, it was confirmed that the triangular, square, and hexagonal topology shapes have excellent performance. The rudder with a square topology shape weighs 78.5% of the rudder with a triangular shape, and the square topology shape is considered to superior in terms of weight reduction.

Analysis of major issues in the field of Maritime Autonomous Surface Ships using text mining: focusing on S.Korea news data (텍스트 마이닝을 활용한 자율운항선박 분야 주요 이슈 분석 : 국내 뉴스 데이터를 중심으로)

  • Hyeyeong Lee;Jin Sick Kim;Byung Soo Gu;Moon Ju Nam;Kook Jin Jang;Sung Won Han;Joo Yeoun Lee;Myoung Sug Chung
    • Journal of the Korean Society of Systems Engineering
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    • v.20 no.spc1
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    • pp.12-29
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    • 2024
  • The purpose of this study is to identify the social issues discussed in Korea regarding Maritime Autonomous Surface Ships (MASS), the most advanced ICT field in the shipbuilding industry, and to suggest policy implications. In recent years, it has become important to reflect social issues of public interest in the policymaking process. For this reason, an increasing number of studies use media data and social media to identify public opinion. In this study, we collected 2,843 domestic media articles related to MASS from 2017 to 2022, when MASS was officially discussed at the International Maritime Organization, and analyzed them using text mining techniques. Through term frequency-inverse document frequency (TF-IDF) analysis, major keywords such as 'shipbuilding,' 'shipping,' 'US,' and 'HD Hyundai' were derived. For LDA topic modeling, we selected eight topics with the highest coherence score (-2.2) and analyzed the main news for each topic. According to the combined analysis of five years, the topics '1. Technology integration of the shipbuilding industry' and '3. Shipping industry in the post-COVID-19 era' received the most media attention, each accounting for 16%. Conversely, the topic '5. MASS pilotage areas' received the least media attention, accounting for 8 percent. Based on the results of the study, the implications for policy, society, and international security are as follows. First, from a policy perspective, the government should consider the current situation of each industry sector and introduce MASS in stages and carefully, as they will affect the shipbuilding, port, and shipping industries, and a radical introduction may cause various adverse effects. Second, from a social perspective, while the positive aspects of MASS are often reported, there are also negative issues such as cybersecurity issues and the loss of seafarer jobs, which require institutional development and strategic commercialization timing. Third, from a security perspective, MASS are expected to change the paradigm of future maritime warfare, and South Korea is promoting the construction of a maritime unmanned system-based power, but it emphasizes the need for a clear plan and military leadership to secure and develop the technology. This study has academic and policy implications by shedding light on the multidimensional political and social issues of MASS through news data analysis, and suggesting implications from national, regional, strategic, and security perspectives beyond legal and institutional discussions.

Modeling of Scattered Signal from Ship Wake and Experimental Verification (항적 산란신호의 모델링과 실험적 검증)

  • Ji, Yoon-Hee;Lee, Jae-Hoon;Kim, Jea-Soo;Kim, Jung-Hae;Kim, Woo-Shik;Choi, Sang-Moon
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.1
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    • pp.10-18
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    • 2009
  • A moving surface vessel generates a ship wake which contains a cloud of micro-bubbles with radii ranging between 8200μm. Such micro-bubbles can be detected by active sonar system for more than ten minutes depending on the size and speed of the surface vessel. In this paper, a reverberation model for the ship wake is presented. The developed model consists of the acoustic scattering model due to the distribution of the micro-bubbles and the kinematic model for the moving active sonar. The acoustic scattering model is based on the volume integration, where the volume scattering strengths are obtained from the spatial distribution of micro-bubbles. Since the directivity and look-direction of active sonar are important factors for moving active sonar, the kinematic model utilizes the Euler transformation to obtain the relative motion between the global and local coordinates. In order to verify the developed model, a series of sea experiment was executed in September 2007 to obtain the spatial-temporal distribution of a bubble cloud, and analyzed to be compared with the simulation results.

Numerical Study on Effect of Longitudinal Center of Gravity (LCG) Changes on Cruise-Ship Resistance in Shallow Water (천수 효과를 고려한 무게중심과 수심 변화에 따른 유람선의 저항성능에 대한 전산유체역학 해석 연구)

  • Michael;Kwang-Cheol, Seo;Kyoung-Woo, Lee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.5
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    • pp.506-515
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    • 2024
  • Owing to the interaction between a ship and the river bed, several phenomena resulting in increased resistance may have occurred. This increase in resistance is primarily due to the wave-making performance. Thus, this study aims to reduce the wave-making resistance by optimizing the performance of an electric canal cruise through changing the longitudinal center of gravity (LCG). Numerical simulations are performed to obtain the lowest resistance by optimizing the LCG position; subsequently, the ef ect of water depth is included as the next variable. Results show that LCG variations of 37.5%-52.5% Lpp can result in a wide range of total resistance. In deep water, a 72.67% resistance gap is achieved by comparing the highest and lowest resistances, whereas a slightly lower gap of up to 62.97% is achieved in shallow water. Additionally, smaller water depths correspond to higher resistance. The resistance increased by a maximum of 67.68% in shallow water measuring 1.5 m, as compared with the case of deep water. This increase in resistance is primarily due to wave-making resistance, which constitutes 84.99% of the total resistance.

A Study on Automatic Bridge Lantern Support for Safe Bridge Lantern Inspection (안전한 교량등 점검을 위한 자동 교량등 지지대에 관한 연구)

  • Min-Yong Lim;Seung-Gi Gug
    • Journal of Navigation and Port Research
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    • v.48 no.4
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    • pp.267-273
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    • 2024
  • Bridge lanterns are installed on bridges or piers to signal the presence of these structures on navigational routes and navigable waters, and they fall under the category of light wave signals in Aids to Navigation. In Korea, medium to large bridges installed over major rivers and seas are equipped with bridge lanterns, which are necessary for routes frequented by ships and require periodic inspections on a monthly or multi-month basis. However, most bridge lanterns are mounted externally on bridge railings as fixed or manual rotary supports, posing a high risk of fatal falls during inspections. Furthermore, high -traffic bridges demand quick maintenance works due to complaints about traffic disruption, thus increasing work hazards. Consequently, this study introduced a tailored automatic bridge lantern support concept based on different types of bridge lantern installations, aiming for safe and rapid inspections. Additionally, the study sought to achieve full automation of the bridge lighting system by integrating it with a management program for monitoring and controlling bridge lanterns, utilizing both wired and wireless communication technologies. These findings provide foundational design data for new and refurbished bridges that will be installed in the future.

A Study on the Water Exchange Plan with Disaster Prevention Facilities in Masan Bay (마산만 재해방지시설을 이용한 해수교환 방안에 관한 연구)

  • Kim, Gweon-Su;Ryu, Ha-Sang;Kim, Kang-Min
    • Journal of Navigation and Port Research
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    • v.37 no.6
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    • pp.637-645
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    • 2013
  • Masan bay with a semi-enclosed waters has serious water quality problems due to the low flow and river pollution load from land, and shows the vulnerable locational characteristics to storm surge. We are seeking the way of both operating disaster prevention facilities and water quality improvement measures in the bay. That is, the water was exchanged using the head difference occurred by operating disaster prevention facilities. The location of disaster prevention facilities was assumed to be in the inlet of the bay, in the vicinity of Machang bridge, and in the vicinity of Dot island and the operation time was assumed to be early morning hours(01~05) considering the number of shipping passage and annual tide, and spring tide of the largest head difference. In addition, the experiment case of water exchange including the in-outflow feeder pipe was tested. According to the simulation results, water exchange rate in all experiments has shown a steady increase. Water exchange rate of the whole of Masan bay in the case of present is 38.62%. The water exchange rate of the inside of Masan bay compared with the inlet of bay, appeared to be very low. Thus, we judged that the characteristics of semi-enclosed waters were well reproduced. On the results of the experiment of disaster prevention facilities and in-outflow feeder pipe, the case of the operation of disaster prevention facilities, water exchage rate is high compared with the case of present. And, the higer the operating frequency, the more water exchange is appeared. The cases of water exchange prevention facilities through the in-outflow feeder pipe caused by the head difference, also showed the higest improvement of the water quality. Compared with the south of Machang bridge, the effect of water exchange was better in the inlet of Masan bay and Dot island. On the other hand, the inlet of Masan bay is higer than Dot island as for water exchange of the whole of Masan bay, but opposite, water change rate including Masan inside was higher in the case of Dot island.

Acute Toxic Effects of Hull In-water Cleaning Wastewater on Embryonic Flounder (Paralichthys olivaceus) (넙치 배아의 선체청소배출수 급성 독성 영향)

  • Seong Hee Mun;Jee-Hyun Jung
    • Journal of Marine Life Science
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    • v.9 no.2
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    • pp.68-83
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    • 2024
  • Antifouling paints, which contain biocidal compounds, are applied to boat and ship hulls to prevent or minimize the attachment of fouling organisms. Despite the potential toxicity risk associated with these pollutants, there is a limited number of studies investigating and monitoring the toxic effects on embryonic fish using hull in-water cleaning (IWC) wastewater collected from ship. In this study, hull IWC wastewater from ship was collected from a ship in 2022 and toxic effect assessments were conducted on fertilized embryonic Olive flounder (Paralichtys olivaceus). After dividing the IWC wastewater into untreated wastewater and filtered wastewater, fertilized embryos were exposed to various dilution factors (10-, 100-, and 1000-fold dilutions). Chemical analysis of the IWC wastewater revealed high proportions of Cu, Fe, and Zn. There was no significant difference in the mortality of embryonic flounder exposed to untreated wastewater compared to filtered wastewater. However, malformations in morphogenesis, including pericardial edema, dorsal curvature, tail fin fold defects, and developmental delays, were observed in fertilized embryos following exposure to IWC from ship. To understand the molecular biology of malformation, eight genes related to (heart formation (nkx2.5, NK2 NK2 homeobox 5; SOX6, SRY-box-containing gene 6; robo1, roundabout receptor1), bone malformation (bmp4, bone morphogenetic protein 4), fin malformation (plod2, procollagen-lysine 2-oxo-glutarate 5-dioxygenase 2, furin, furin, paired basic amino acid cleaving enzyme; wnt3a, Wnt family member 3a), and tumors (TP73, tumor protein p73) were evaluated using qRT-PCR. To clarify the potential toxic effects of IWC wastewater, we also conducted RNA-seq (high-throughput sequencing) on embryonic flounder exposed to hull IWC wastewater. In embryonic flounder exposed to IWC wastewater, genes related to nervous system development, cell development, muscle development, and animal organ development pathways were significantly differentially expressed. This study provided crucial evidence of the risks associated with IWC wastewater when exposed to marine organisms. Taken together, these results may inform strategies to improve hull-cleaning wastewater pollution management to better protect coastal ecosystems.