• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.115-127
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• 2021

With the development of science and technology around the world, the realm of cyberspace, following land, sea, air, and space, is also recognized as a battlefield area. Accordingly, it is necessary to design and establish various elements such as definitions, systems, procedures, and plans for not only physical operations in land, sea, air, and space but also cyber operations in cyberspace. In this research, the importance of cyber targets that can be considered when prioritizing the list of cyber targets selected through intermediate target development in the target development and prioritization stage of targeting processing of cyber operations was selected as a factor to be considered. We propose a method to calculate the score for the cyber target and use it as a part of the cyber target prioritization score. Accordingly, in the cyber target prioritization process, the cyber target importance category is set, and the cyber target importance concept and reference item are derived. We propose a TIR (Target Importance Rank) algorithm that synthesizes parameters such as Event Prioritization Framework based on PageRank algorithm for score calculation and synthesis for each derived standard item. And, by constructing the Stuxnet case-based network topology and scenario data, a cyber target importance score is derived with the proposed algorithm, and the cyber target is prioritized to verify the proposed algorithm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.206-214
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• 2023

Fish school monitoring technology is utilized for various purposes, such as boat fishing and resource surveys. With advancements in information and communication technology, this technology has expanded its application to remote areas. Its significance has grown in fishing sites, particularly for improving the efficiency and cost-effectiveness of set-net fishing. Set-net fishing gears are not limited to coastal areas, but are also installed in inland and remote sea regions. Consequently, fishermen require technology that allows them to quickly transmit information about approaching fish schools and enables them to perform long-term monitoring. The development of remote monitoring technology for set-net fish schools must consider crucial design factors such as communication range, transmission speed, power consumption of information modules, and operational expenses. In this study, we developed a low-power remote monitoring module for set-net fish school based on WCDMA. The module was specifically designed to minimize power consumption, allowing for communication over long distances and extended operation times in set-net fishing applications. Furthermore, we developed a web server software application that enables remote access to fish schools and provides real-time weather information. The performance of the developed module was evaluated through set-net fishing site application and experiments with moving ships on the sea. The experimental results demonstrated that the remote monitoring system, consisting of the developed low-power remote monitoring module for set-net fish school based on WCDMA and a fish finder, had an average power consumption of 4.6 W, a maximum communication range of 22.84 km, and a data transmission and reception rate of 98.79%. The maximum fish school information transmission and reception rate was 97.26%

• The Journal of the Acoustical Society of Korea
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• v.43 no.4
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• pp.445-454
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• 2024

To detect underwater targets using sonar, sonar performance analysis that reflects the ocean environment and sonar characteristics must be performed. Sonar performance modeling of passive and monostatic sonar can be performed relatively quickly even considering the ocean environment. However, since bistatic and multistatic sonar performance modeling require higher computational complexity and much more time than passive or monostatic sonar cases, they have been performed by simplifying or not considering the ocean environment. In thisstudy, the effects of reverberation and ocean environment in bistatic sonar performance were analyzed using the bistatic reverberation modeling in the Ulleung Basin of the East Sea. As the sonar operation depth approaches the sound channel axis, the influence of the bathymetry on sound propagation is reduced, and the reverberation limited environment is formed only at short distances. Finally, it was confirmed that similar trends appeared through comparison between the simplified and elaborately calculated sonar performance modeling results.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.379-384
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• 2014

In case of sunken tankers, remaining-oil recovery operation should be conducted due to possible oil spill accident. However, the deep sea operation make difficulties in checking the completion of remaining oil recovery process, therefore the work termination procedure is very important. In this paper, a reasonable work termination procedure through the comparison and analysis of two cases(Youil No.1 and Osung No.3, Kyung-Shin) which were performed in different method, using disparate equipment. By investigating previously applied methods and techniques, work speed, safety and expenses were compared. The proposed ending procedure of the remaining-oil recovery project is to recover the remaining oil from each cargo tanks and to clean up such tanks whilst an independent surveyor proceeds to a confirmation procedure whereby said surveyor checks out whether any remaining oil exists by putting a stick in each cleaned up tanks and opening up the hatch cover of the tanks or the top place of the tanks to confirm the cleanness of oil. Such procedure shall be done through discussion by the ordering party, contractor and the independent surveyor all together with a flexible application.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.12-24
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• 2018

This study was conducted in order to improve opening efficiency of the miniaturized large-scale net for anchovy boat seine gear to reduce the fleet size. Field experiments were performed to observe geometry of nets by catcher boats. When the distances between the two ships were 150, 300 and 450 m, and the speeds of towing nets were 0.6, 0.9, and 1.2 k't, respectively. The vertical opening and actual opening of each part of the miniaturized large-scale net was as follows: the front part of the wing net, 8.7-13.3 m, 51-78%; the middle part of the wing net, 28.1-34.2 m, 55-67%; the entrance of the inside wing net, 31.3-38.5 m, 60-73%; the square and bosom, 22.7-29.6 m, 47-62%; the entrance of the body net, 20.9-26.4 m, 42-52%; the entrance of the bag net, 17.2-21 m, 72-89%; the flapper, 13.2-15.3 m, 78-83%; and the end of the bag net, 13.2-15.7 m, 72-75%. By connecting the net pendants with the front part of the wing net, the opening of the front part of the wing net was significantly improved compared to the traditional gear, which ensured both the wing net and the inside wing net with a normal net height. This, in turn, increased the efficiency of herding. The height of the body and bag nets was also higher than that of the tradition gear. In particular, the body net attached to the gear significantly improved the pocket shape of the gear and reduced the number of fish that were caught and escaped from the bag net, which increased the rate of fishing. The tension of towing nets was measured approximately between 2,958 and 7,110 kg, which indicates that the fleet can tow nets with 350 ps, the standard engine horse power. The fishing operation time was shortened compared with of the existent net, and the large-scale buoy attachment operation was also possible to operate the ship without fish detecting boat.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.61-67
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• 2004

The development motive and maintenance of navigation system were military strategy purpose since middle of 20th century. During cold war period between the United States and the Soviet since the Second World War, advanced navigation system that two countries are responded individually have done development competitively. These systems are exhibited on general except military purpose gradually and are taking charge of point role in economy transport activity such as transportation of logistics between the country. Navigation system can divide into ground system and satellite system. Representative system of ground system is Loran-C(Long Range Navigation), and representative system of satellite system is GPS(Global Position System). Loran-C system is a system that use much in all the world country sea and ground, but GPS and DGPS that present is a satellite navigation system are used much. According to development of satellite system, examine about actual conditions of Loran-C navigation system and practical use plan in this paper because there is controversy about role of Loran-C navigation device along with Loran-C's operation and user decrease, and discusses for Loran-C's development direction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.153-159
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• 2016

Gwangyang traffic safety designated area is composed of 3 fairways (Deep water fairway, inbound fairway, and outbound fairway). However, inbound vessels can't use this passage because of Samyeo rock and artificial fishing banks in inbound route. The problem with the rocks and artificial fishing banks has been raised by ship navigators and authorities of the port. This research is about the safety evaluation and management plan of the passage, and we conducted maritime traffic simulation using a model based on a ship operator risks. As a result, assuming that future marine traffic volume is the same as the present, and if the ship operators use 3 fairways and not two, it showed risk reduction of 46.4 % (vessels over 50,000 DWT using DW route) and 57.1 % (vessels over 10,000 DWT using DW route). Also, in a traffic volume condition which is the same as the present, to induce vessels over 50,000 DWT to use DW route is effective in mitigating of risks. Meanwhile, in a condition which increased the traffic volume by 150 %, it is more effective to induce vessels to use DW route. This research is the result of analysis using the model based on ship operator risks, and not cost-effectiveness analysis on the removal of Samyeo rock and artifical fishing banks. This research is expected to be used on setting up the sea route and management plan (particularly, restriction on passing DW route).

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.666-673
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• 2013

This paper proposes the performance evaluation test of attitude heading reference system (AHRS) suitable for small high speed autonomous underwater vehicle(AUV). Although IMU can provides the detail attitude information, it is sometime not suitable for small AUV with short operation time in view of price and the electrical power consumption. One of alternative for tactical grade IMU is the AHRS based micro-machined electro mechanical system(MEMS) which can overcome many problems that have inhibited the adoption of inertial system for small AUV such as cost and power consumption. A cost effective and small size AHRS which incorporates measurements from 3-axis MEMS gyroscopes, accelerometers, and 3-axis magnetometers has been developed to provide a complete attitude solution for AUV and the attitude calculation algorithm is derived based the coordinate transform equation and Kalman filter. The developed AHRS was validated through various performance tests as like the magnetometer calibration, operating experiments using land mobile vehicle and flight motion simulator (FMS). The test of magnetometer calibration shows the developed MEMS AHRS is robust to the external magent field change and the test with land vehicle proves the leveling error of developed MEMS AHRS is below $0.5^{\circ}/hr$. The results of FMS test shows the fact that AHRS provides the measurement with $0.5^{\circ}/hr$ error during 5 minutes operation time. These results of performance evaluation tests showed that the developed AHRS provides attitude information which error of roll and pitch are below $1^{\circ}$ and the error of yaw is below $5^{\circ}$ and satisfies the required specification. It is expected that developed AHRS can provide the precise attitude measurement under sea trial with real AUV.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.47-59
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• 2017

This study aims to assess offshore wind energy resources around Jeju Island using the InVEST Offshore Wind model. First the wind power density around the coast of Jeju was calculated using reanalysis data from the Korean Local Analysis and Prediction System (KLAPS). Next, the net present value (NPV) for the 168MW offshore wind farm scenario was evaluated taking into consideration factors like costs (turbine development, submarine cable installation, maintenance), turbine operation efficiency, and a 20year operation period. It was determined that there are high wind resources along both the western and eastern coasts of Jeju Island, with high wind power densities of $400W/m^2$ calculated. To visually evaluate the NPV around Jeju Island, a classification of five grades was employed, and results showed that the western sea area has a high NPV, with wind power resources over $400W/m^2$. The InVEST Offshore Wind model can quickly provide optimal spatial information for various wind farm scenarios. The InVEST model can be used in combination with results of marine ecosystem service evaluation to design an efficient marine spatial plan around Jeju Island.

• Journal of National Security and Military Science
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• s.7
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• pp.271-303
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• 2009

"Ubiquitous sensor network" definition is this-Someone attaches electro-magnetic tag everything which needs communication between man to man, man to material and material to material(Ubiquitous). By using attached every electro-magnetic tag, someone detects it's native information as well as environmental information such as temperature, humidity, pollution and infiltration information(Sensor). someone connects it realtime network and manage generated information(Network). 21st century's war is joint combined operation connecting with ground, sea and air smoothly in digitalized war field, and is systematic war provided realtime information from sensor to shooter. So, it needs dramatic development on watch reconnaissance, command and control, pinpoint strike etc. Ubiquitous computing and network technologies are essential in national defense to operate 21st century style war. It is possible to use many parts such as USN combined smart dust and sensor network to protect friend unit as well as to watch enemy's deep area by unmanned reconnaissance, wearable computer upgrading soldier's operational ability and combat power dramatically, RFID which can be used material management as well as on time support. Especially, unmanned watch system using USN is core part to transit network centric military service and to get national defense efficiency which overcome the dilemma of national defense person resource reducing, and upgrade guard quality level, and improve combat power by normalizing guardian's bio rhythm. According to the test result of sensor network unmanned watch system, it needs more effort and time to stabilize because of low USN technology maturity and using maturity. In the future, USN unmanned watch system project must be decided the application scope such as application area and starting point by evaluating technology maturity and using maturity. And when you decide application scope, you must consider not only short period goal as cost reduction, soldier decrease and guard power upgrade but also long period goal as advanced defense ability strength. You must build basic infra in advance such as light cable network, frequency allocation and power facility etc. First of all, it must get budget guarantee and driving force for USN unmanned watch system project related to defense policy. You must forwarded the USN project assuming posses of operation skill as procedure, system, standard, training in advance. Operational skill posses is come from step by step application strategy such as test phase, introduction phase, spread phase, stabilization phase and also repeated test application taking example project.