• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.149-163
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• 2016

Seafarers are an essential resource in maritime industries, which provide navigation skills, vessel maneuvering skills and fishing skills in the fishery industry. They also work as a driving force in pilotage, port operation, vessel traffic service, and marine safety. Other areas in maritime services, which rely on seafarer include safety management of ships, supervisory activities, and maritime accident assessment. In these ways, Korean seafarers have contributed to the growth of Korean economy. However, there have been issues of high separation rate, shortage of supply, multi-nationality, multiplicity of culture caused by employment of foreign seafarers, and aging. The present paper finds that maritime officers and fishery officers demonstrate differences in the statistics of on-board job taking and separation: the separation rate of fishery officers is higher than that of maritime officers. The existing data and statistics by the Korea Seafarer's Welfare & Employment Center could be improved by changing its structure from time series to panel data. The Korea Seafarer's Welfare & Employment Center is the ideal institution for collecting the panel data, as it has already accumulated and published relevant statistics regarding seafarer. The basic design method of the panel data is to adopt and improve it by including the information on ratings of maritime and fishery industries, ranks in a ship, personal information, family life, and career goal. Panel data are useful in short- and long-term forecasts of supply of Korean seafarers; demand evaluation of education, training, and reeducation of the seafarers; demographical dynamic analysis on Korean seafarers; inducement policy of long-term on board job taking in harmony with man-power demands in marine industries such as pilotage service; implementation of job attractiveness policy on Korean seafarers; and employment stabilization of Korean seafarers.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.387-393
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• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.334-345
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• 2022

The Enforcement Decree of the Framework Act on the Management of Disasters and Safety Article 3-2 specifies two 'disaster management supervision agencies' for responding to shipping disasters. These are the Korea Coast Guard, which is an on-scene disaster-responding and coordinating agency, and the Ministry of Ocean and Fisheries, which is a government department, thereby leading to possibilities for confusion. In the case of shipping disasters, where a personnel entitled full power to deal with shipping disasters is designated and his/her powers and duties are clearly made, relationship of leading and supporting agencies is made clear, and command system is simplified, an efficient response to shipping disasters is made possible. In the management of shipping disasters, all the disaster management processes, that is, prevention-preparedness-response-recovery, should be dealt with systematically and consistently. Notably, to swiftly and efficiently cope with a disastrous situation, the decision-making and command system must be simplified. The establishment of a command system and decision-making must be made independently, based on expertise. In the US, irrespective of the type of disasters, the FEMA plays a leading role and the USCG responds a response to maritime disasters by establishing the Incident Command System or Unified Command System that is an incident management system. In the UK, the MCA supervises an event and responds to it, and the SOSREP has full power to work with command and coordination independently. SOSREP, among others, is necessary to prevent an inefficient dealing of a shipping disaster owing to confrontation between participants. With reference to such leading States' practice, the Korean government should make a standardized and simplified response to maritime disasters. This study deals with a new maritime disaster responding system and provides an idea of the revision of the existing legal regime.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.483-489
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• 2016

The type approval test for USCG Phase II must be satisfied such that living natural biota occupy more than 75 % of whole biota in a test tank. Thus, we harvested a community of natural organisms using a net at Masan Bay (eutrophic) and Jangmok Bay (mesotrophic) during winter season to meet this guideline. Furthermore, cell viability was measured to determine the mortality rate. Based on the organism concentration volume (1 ton) at Masan and Jangmok Bay, abundance of ${\geq}10$ and $<50{\mu}m$ sized organisms was observed to be $4.7{\times}10^4cells\;mL^{-1}$and $0.8{\times}10^4cells\;mL^{-1}$, and their survival rates were 90.4 % and 88.0 %, respectively. In particular, chain-forming small diatoms such as Skeletonema costatum-like species were abundant at Jangmok Bay, while small flagellate ($<10{\mu}m$) and non chain-forming large dinoflagellates, such as Akashiwo sanguinea and Heterocapsa triquetra, were abundant at Masan Bay. Due to the size-difference of the dominant species, concentration efficiency was higher at Jangmok Bay than at Masan Bay. The mortality rate in samples treated by Ballast Water Treatment System (BWMS) (Day 0) was a little lower for samples from Jangmok Bay than from Masan Bay, with values of 90.4% and 93%, respectively. After 5 days, the mortality rates in control and treatment group were found to be 6.7% and >99%, respectively. Consequently, the phytoplankton concentration method alone did not easily satisfy the type approval standards of USCG Phase II ($>1.0{\times}10^3cells\;mL^{-1}$ in 500-ton tank) during winter season, and alternative options such as mass culture and/or harvesting system using natural phytoplankton communities may be helpful in meeting USCG Phase II biological criteria.

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

• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.175-194
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• 2014

Because the thawing of the Arctic ocean is slowly accelerating due to global warming, recently exploring resources in Arctic ocean and transporting resources by using the North Pole route have been getting spotlight. Since the original route transported by the Suez Canal from Korea to Europe could be shorten about 8,000km in distance(decreased about 38% compared to the original route), which means shortening about 10 voyage dates, it is expected to bring huge logistics cost reduction. Once the North Pole route is commercialized successfully, it would be one of the most important variables that affects future of Busan port and guides for economic development of Busan. Therefore, the purpose of this study is to analyze Busan port and the economic growth of Busan area by researching promising industry, based on the effect of freight transporting by the Northern sea route on the economy of Busan. For this study, questionnaire surveys and interviews were conducted for 64 people of experts in the shipping and port industry, relevant government, and academics. The survey finding shows that port logistics industry is a promising business in Busan in terms of its growth and competitiveness. It is necessary to develop feeder network facilities that prepare for commercialization of the Northern sea route as a short and medium term plan and provide professional manpower training in polar regions. Ship supply business would also play an important role. It is identified that revitalization of shipbuilding and ocean plant industry should be done in terms of Arctic business. With regard to the fishery industry it is found that modernization of fishery ship and development of fishery equipment used in polar areas should be carried out.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.10-20
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• 2014

To study the water-entry impact noise, on-board experiment using a small launcher firing various objects was performed in the Yellow Sea. As the launcher fires a cylindrical object from the ship vertically, generated noise is measured with a hydrophone on the starboard of Chung-hae, Marine surveyor. Three types of cylindrical objects, which have noses of flat-faced, conical, and hemisphere, were used during the experiment. The measured noise exhibits a time-dependency which can be divided into three phases: (1) initial impact phase, (2) open cavity flow phase, (3) cavity collapse and bubble oscillation phase. In most cases, the waveform of bubble oscillation phase is dominant rather than that of initial impact phase. Pinch-off time, where a cavity begins to collapse, occurs at 0.18 ~ 0.2 second and the average lasting time of bubble was 0.9 ~ 1.3 second. The energy of water-entry impact noise is focused in the frequency region lower than 100 Hz, and the generated noise is influenced by the nose shapes, object mass, and launching velocity. As a result, energy spectral density on the bubble frequency is higher in the order of flat-faced, conical, hemisphere nose, and the increase of initial energy raises the energy spectral density on the bubble frequency in the cylinder body of same shape. Finally, we compare the measurements with the simulated signals and spectrum based on the bubble explosion physics, and obtain satisfactory agreements between them.

• Strategy21
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• s.31
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• pp.57-84
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• 2013

North Korea's continuous threats and provocative behaviors have aggravated tension on the Korean peninsula particularly with the recent nuclear weapons test. South Korea's best way to cope with this situation is to maintain the balance among three policy directions: dialogue, sanctions, and deterrence. Among the three, I argue that deterrence should be prioritized. There are different sources of deterrence such as military power, economic power, and diplomatic clouts. States can build deterrence capability independently. Alternatively, they may do so through relations with other states including alliances, bilateral relations, or multilateral relations in the international community. What South Korea needs most urgently is to maintain deterrence against North Korea's local provocations through the enhancement of independent military capability particularly by addressing the asymmetric vulnerability between militaries of the South and the North. Most of all, the South Korean government should recognize the seriousness of the negative consequences that North Korea's 'Nuclear shadow strategy' would bring about for the inter-Korea relations and security situations in Northeast Asia. Based on this understanding, it should develop an 'assertive deterrence strategy' that emphasizes 'multi-purpose, multi-stage, and tailored deterrence whose main idea lies in punitive retaliation.' This deterrence strategy requires a flexible targeting policy and a variety of retaliatory measures capable of taking out all targets in North Korea. At the same time, the force structures of the army, the air force, and the navy should be improved in a way that maximizes their deterrence capability. For example, the army should work on expanding the guided missile command and the special forces command and reforming the reserve forces. The navy and the air force should increase striking capabilities including air-to-ground, ship-to-ground, and submarine-to-ground strikes to a great extent. The marine corps can enhance its deterrence capability by changing the force structure from the stationary defense-oriented one that would have to suffer some degree of troop attrition at the early stage of hostilities to the one that focuses on 'counteroffensive landing operations.' The government should continue efforts for defense reform in order to obtain these capabilities while building the 'Korean-style triad system' that consists of advanced air, ground, and surface/ subsurface weapon systems. Besides these measures, South Korea should start to acquire a minimum level of nuclear potential within the legal boundary that the international law defines. For this, South Korea should withdraw from the Nuclear Non-proliferation Treaty. Moreover, it should obtain the right to process and enrich uranium through changing the U.S.-South Korea nuclear cooperation treaty. Whether or not we should be armed with nuclear weapons should not be understood in terms of "all or nothing." We should consider an 'in-between' option as the Japanese case proves. With regard to the wartime OPCON transition, we need to re-consider the timing of the transition as an effort to demonstrate the costliness of North Korea's provocative behaviors. If impossible, South Korea should take measures to make the Strategic Alliance 2015 serve as a persisting deterrence system against North Korea. As the last point, all the following governments of South Korea should keep in mind that continuing reconciliatory efforts should always be pursued along with other security policies toward North Korea.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.279-286
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• 2015

The rapid increase of the current marine accidents is mainly due to the human execution errors. In an effort to address this, various kinds of researches such as construction of the digital vessels and vessel information monitoring systems have been conducted. But for safe navigation of vessels, it lack on systems study which can efficiently store, utilize and manage the mass data accepted by the vessel. In this paper, we propose a VWS(Virtual World System) that is based on the architecture of intelligent systems RVC(Reactive Layer-Virtual World-Considerative Layer) model of intelligent autonomous navigation system. VWS is responsible to store all the necessary information for safe navigation of the vessel and the information services to the sub-system of intelligent autonomous navigation system. VWS uses topology database to express the specific problem area, and utilizes a scheduling to reflect the characteristics of the real-time processing environment. Also, Virtual World defines API for the system to reflect the characteristics of the distributed processing environment. As a case study, the VWS is applied to a intelligent ship autonomous navigation system, and simulation is done to prove the effectiveness of the proposed system.

• Korean Journal of Remote Sensing
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• v.30 no.6
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• pp.797-807
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• 2014

The Sea Surface Temperature (SST) is one of the most important oceanic environmental factors in determining the change of marine environments and ecological activities. Satellite thermal infrared images can be effective for understanding the global trend of sea surface temperature due to large scale. However, their low spatial resolution caused some limitations in some areas where complicated and refined coastal shapes due to many islands are present as in the Korean Peninsula. The coastal ocean is also very important because human activities interact with the environmental change of coastal area and most aqua farming is distributed in the coastal ocean. Thus, low-cost airborne thermal infrared remote sensing with high resolution capability is considered for verifying its possibility to extract SST and to monitor the changes of coastal environment. In this study, an airborne thermal infrared system was implemented using a low-cost and ground-based thermal infrared camera (FLIR), and more than 8 airborne acquisitions were carried out in the western coast of the Korean Peninsula during the periods between May 23, 2012 and December 7, 2013. The acquired thermal infrared images were radiometrically calibrated using an atmospheric radiative transfer model with a support from a temperature-humidity sensor, and geometrically calibrated using GPS and IMU sensors. In particular, the airborne sea surface temperature acquired in June 25, 2013 was compared and verified with satellite SST as well as ship-borne thermal infrared and in-situ SST data. As a result, the airborne thermal infrared sensor extracted SST with an accuracy of $1^{\circ}C$.