• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.667-669
• /
• 2021

Recently, RFID/USN technology has been applied in various fields such as logistics, environment, education, home network, disaster prevention, military, and medical care, but despite the remarkable development of RFID/USN technology, it is difficult to apply it to marine industry due to the characteristics of poor marine environment. Therefore, satellites are mainly used in the marine sector, and existing communication networks are used in the coast, so measures for forming a shelf-only short-range network in the ocean are being considered. In this paper, we consider the use of drones as mobile base stations of USN as a base station role using USN in existing PS-LTE and LTE networks.Since autonomous navigation vessels are aiming for the intelligent system, the number of crew and labor force should be reduced and the function of autonomous network formation in the form of more stable and intelligent ICT convergence technology should be strengthened.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.161-164
• /
• 2022

부유식 라이다는 해상풍력단지 조성시 필수적으로 수행하고 있는 풍황관측 업무에 새로운 패러다임을 제공하고 있는 시스템으로, 전통적으로 풍황관측을 수행하고 있던 해상기상관측탑을 대체하여 사업 초기의 대규모 공사를 획기적으로 축소하여 시간과 비용을 절약하고, 환경적 영향을 최소화 하며, 지역사회의 반발 요소까지 줄일 수 있어 해당 업계의 표준으로 자리잡고 있는 중이다. 다만 부표식의 동요에 따른 외란적 요소가 관측자료의 신뢰성에 영향을 미치는 만큼 안정적인 플랫폼의 설계 및 검증이 매우 중요한 상황이며, 국내에서는 해당기술에 대한 늦은 진입으로 인해 다수의 외산장비 제조사들이 국내시장까지 선점하고 있는 상황이다. 한국의 서해안은 천해 환경으로 조석차가 매우 커 지역에 따라 강한 조류가 반복적으로 나타나며, 계절별로 상이한 강한 에너지의 파랑이 형성되는 등 플랫폼에 안정도에 많은 영향을 미치는 바다 환경을 갖고 있다. 본 논문에서는 이러한 복잡한 환경적 특성을 갖고 있는 우리나라의 해역에 라이다 운영에 적합한 부표식에 대한 연구를 수행하며, 우선적으로 적용하였던 선박형 부표식의 최적화 설계 및 검증 사례를 소개하고, 향후 다양한 플랫폼 개발에 토대가 되는 중요 개념을 도출하고자 한다.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.3
• /
• pp.298-307
• /
• 2023

Objectives: The purpose of this study is to analyze the recent trends in patients with work-related musculoskeletal disorders in South Korea and to check the major results by reviewing the literature on the risk factors and prevalence of musculoskeletal diseases related to work. Methods: Industrial disaster data from the Ministry of Employment and Labor from 2012 to 2021 were used, and the literature was reviewed regarding risk factors for musculoskeletal diseases related to work using PubMed and RISS. Results: The trend of patients with work-related musculoskeletal disorders has increased overall since 2017 after declining until 2016, with a particularly notable increase in the average annual number of patients with physical burden work. The average annual rate per ten thousand people for patients with body burden work, non-accidental lower back pain, and carpal tunnel syndrome among work-related diseases was high in the mining industry. The average annual rate per ten thousand people for patients with accidental lower back pain was the highest in the fishing industry. Within the manufacturing field, it was the highest in the shipbuilding and ship repair industry. As a result of the literature review, the search rate for work-related musculoskeletal disease papers in unstructured work was high. In addition, physical stress factors were high among risk factors, and pain areas showed a high rate for the waist. Conclusion: Even after the institutional implementation of a hazard investigation system related to musculoskeletal diseases is implemented, the number of patients with occupational musculoskeletal disorders continues to increase. Therefore, it is necessary to conduct regular surveys and implement effective improvement activities for vulnerable industries or occupations.

• Journal of Trauma and Injury
• /
• v.36 no.4
• /
• pp.376-384
• /
• 2023

Purpose: The Armed Forces Trauma Center of Korea was established in April 2022. This study was conducted to report our 1-year experience of treating soldiers with open fractures of the lower extremity. Methods: In this case series, we reviewed the medical records of 51 Korean soldiers with open fractures of the lower extremity between April 2022 and March 2023 at a trauma center. We analyzed patients with Gustilo-Anderson type II and III fractures and reported the duration of transportation, injury mechanisms, injured sites, and associated injuries. We also presented laboratory findings, surgery types, intensive care unit stays, hospital stays, rehabilitation results, and reasons for psychiatric consultation. Additionally, we described patients' mode of transport. Results: This study enrolled nine male patients who were between 21 and 26 years old. Six patients had type II and three had type III fractures. Transport from the accident scene to the emergency room ranged from 75 to 455 minutes, and from the emergency room to the operating room ranged from 35 to 200 minutes. Injury mechanisms included gunshot wounds, landmine explosions, grenade explosions, and entrapment by ship mooring ropes. One case had serious associated injuries (inhalation burn, open facial bone fractures, and hemopneumothorax). No cases with serious blood loss or coagulopathies were found, but most cases had a significant elevation of creatinine kinase. Two patients underwent vascular reconstruction, whereas four patients received flap surgery. After rehabilitation, six patients could walk, one patient could move their joints actively, and two patients performed active assistive movement. Eight patients were referred to the psychiatry department due to suicidal attempts and posttraumatic stress disorder. Conclusions: This study provides insights into how to improve treatment for patients with military trauma, as well as medical services such as the transport system, by revising treatment protocols and systematizing treatment.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.6
• /
• pp.460-472
• /
• 2023

This study was conducted based on the case of an accident (excessive deformation) that occurred during the hydraulic test of a shipboard tank manufactured in accordance with the design regulations. Over-pressure phenomenon was noted as the main cause of accidents in the process of testing tanks without physical damage, which can be found in external factors such as cross-sectional difference between inlet pipe and air pipe and higher water filling rate than the recommended one. The main goal of this paper is to establish a safe water filling rate according to the range of sectional area ratio(SAR) reduced below the regulations for each test situation. The simulation was conducted in accordance with the hydraulic test procedure specified in the Ship Safety Act, and the main situation was divided into two types: filling the tank with water and increasing the water head to the test pressure. The structural safety evaluation of the pressure generated inside the tank and the effect on the structure during the test was reviewed according to the SAR range. Based on the results, guidelines for the optimal filling rate applicable according to SAR during the hydraulic test were presented for the shipboard tanks used in this study.

• Korea Trade Review
• /
• v.45 no.5
• /
• pp.141-159
• /
• 2020

Container terminals at Gwangyang Port are operated by three container operators: A, B and C. Ultimately, there is consensus that a single operator should operate all terminals so that economies of scale can be achieved even in the operation of the container terminal. Integration between operators has a positive effect on both operators and shipping companies. From the operator's point of view, overlapping fixed costs between operators can be unified, reducing overall costs and utilizing spare facilities. On the other hand, from the viewpoint of the shipping company, it is possible to ensure stable use of the port facilities and always allow berthing, reduce days on demurrage and ship waiting, and provide one-stop service for work. However, existing cases of operators' integration or relocation of terminals remained to estimate the expected effects of alternatives, emphasizing only the financial point of view. The port terminal is a large system, and it is important to consider that it is an aggregate of major logistics facilities and equipment. Moreover, if the estimation can be made by quantifying the expected effect, the justification of the terminals' relocation can be further emphasized. Therefore, it is very important to estimate the expected effect from the viewpoint of systemic operation. Moreover, the need for operators' integration can be further emphasized if it can be estimated through quantification of expected effects. Currently, three alternatives are considered as alternatives to the terminals' relocation, and in this study, the optimal plan was derived for the 3 alternatives by the linear planning model of the minimum shuttle transportation cost in the terminal. The optimal plan is alternative 2, which shows the most advantageous integration effect in terms of expected effects. Alternative 2 integrates the B terminal into the C terminal, and the A terminal operates independently as it is.

• Korea Trade Review
• /
• v.45 no.6
• /
• pp.157-179
• /
• 2020

This study presented the results of meta-analysis through topic modeling among the papers published in the Journal of the International Trade Association for the purpose of presenting academic research trends in the field of trade insurance and future research directions. Among the total 2,010 papers included in the Journal of the Korea International Trade Association, the analyzed paper covers the subject of trade-related insurance. According to detailed topics, 33 marine insurance (42.31%), 16 export insurance (20.51%), 11 hull insurance (14.10%), and 18 others (23.08%), and 4 other products liability insurance. According to the empirical analysis results, Topic 1 was classified as marine insurance, airworthiness, notice obligation, and collateral, and Topic 2 was derived as a representative topic for loading insurance, emergency risk, and immunity as export insurance. And Topic 3 was classified as vessel, sinking and container in relation to ship insurance, and Topic 4 was analyzed as an important topic such as manufacture and British marine insurance. Through the analysis results, we selected the representative topic used for the trade insurance topic and looked at the status of major research. Trade insurance is an area that requires the development of more theoretical and practical research subjects as an optimal risk management means in international trade transactions. To this end, first, support from the Korea International Trade Association is needed to establish a continuous research subject sharing system for the development of research subjects in the field of trade insurance. Second, academic journal operation management must be continuously managed in which academic research papers can be submitted and published.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.60 no.1
• /
• pp.71-79
• /
• 2024

In compliance with environmental regulations at sea and the introduction of unmanned autonomous ships, electric propulsion ships are garnering significant attention. Induction machines used as propulsion electric motor (PEM) have maintenance advantages, but speed control is very complicated and difficult. One of the most commonly used techniques for speed control is DTC (direct torque control). DTC is simple in the reference frame transformation and the stator flux calculation. Meanwhile, two-level and three-level voltage source inverters (VSI) are predominantly used. The three-level VSI has more flexibility in voltage space vector selection compared to the two-level VSI. In this paper, speed is controlled using the DTC method based on the specifications of the PEM. The speed controller employs a PI controller with anti-windup functionality. In addition, the characteristics of the two-level VSI and three-level VSI are compared under identical conditions. It was confirmed through simulation that proper control of speed and torque has been achieved. In particular, the torque ripple was small and control was possible with a low DC voltage at low speed in the three-level VSI. The study confirmed that the application of DTC, using a three-level VSI, contributes to enhancing the system's response performance.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.30 no.2
• /
• pp.217-225
• /
• 2024

Even after the introduction of Global Maritime Distress and Safety System (GMDSS), many maritime accidents occur. A method of transmitting a rescue signal when a person falls into the water from a ship is currently being researched and developed in various ways, but no products have been developed that use frequencies allocated for maritime mobile service. Accordingly, in this study, we designed and produced a man-over-board (MOB) device by applying Group B AMRD technologies, which were adopted through the latest revision of the International Telecommunication Union (ITU). In addition, a receiver and user interface were built to verify the performance of the transmitter, and we confirmed that it can be used in conjunction with existing electronic charts. This MOB device satisfies the general and technical requirements of Group B AMRD using AIS technology and uses integrated components for miniaturization for easy portability in a maritime environment. We expect that it will achieve excellent AIS communication and be essential in rapid response and safety in emergency scenarios.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.3
• /
• pp.9-15
• /
• 2016

We investigated >$50-{\mu}m$ marine planktonic organisms (mainly zooplankton) using a bongo net in Masan Bay and Jangmok Bay in order to harvest 75% of natural communities based on Phase-II approval regulations by the United States Coast Guard (USCG). The concentrated volume (in 1 ton) and abundance of zooplankton were $1.8{\times}10^7ind.ton^{-1}$ and $2.3{\times}10^7ind.ton^{-1}$, and their survival rates were 82.6% and 80.1%, respectively. The community structure in Jangmok Bay was similar to that in Masan Bay, and dominant species were adult and immature groups (stage IV) of genus Acartia. Harvested populations were inoculated in a 500-ton test tank. Although the population abundances were $6.0{\times}10^4ind.ton^{-1}$ for both bay samples, the mortality rates were higher in the Masan Bay population (32%) than the Jangmok Bay population (20%). We considered the reason to be that there were 30% more immature individuals of Acartia from Masan Bay than from Jangmok Bay. The younger population may have been greatly stressed by the moving process and netting gear. After applying a Ballast Water Treatment System (BWTS) using a sample form Jangmok Bay, the mortality rates in the treatment groups were found to be 100% after 0 days and 5 days, implying that the BWTS worked well. During the winter season, the zooplankton concentration method alone did not easily satisfy the approval standards of USCG Phase II (> $10{\times}10^4ind.ton^{-1}$ in the 500 ton tank). Increasing the netting frequency and additional fishing boats may be helpful in meeting the USCG Phase II biological criteria.