• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.850-856
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• 2012

Bilateration using two fixed nodes has been used in the field of the real time indoor location system in the narrow space such as building or ship passage. However, as the distance between the fixed nodes increases or any obstructions exist in their zone, it is difficult to detect the location of mobile node(user) due to the degradation of its reception ratio. In order to compensate for these problems, this paper presents, based on IEEE 802.15.4a chirp signal, a new real time indoor location system using stride measurement algorithm which can calculate the location through sensors attached to user. The proposed system consists of an ultrasonic sensor to measure the leg length, a geomagnetic sensor to recognize the user's orientation, and an inertial sensor to obtain the angle between the legs. The experimental results are shown that the proposed system has twice or more accurate output compared with conventional indoor location method in the section which is partially out of communication reachability.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.423-428
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• 2009

Recently, the marine traffics have been increased along with enlargement of overseas commerce. Increasing the marine traffic may make higher the risk of marine accidents. Especially, the rate of accidents on costal area are more frequently. As if the marine safety information can be afforded to vessel and shore, the accident rate would be down. AIS AtoN is the navigational safety support device which is subject to functional requirements of IALA and technical standards of ITU. In this paper, we extend and implement the user-defined specification of AIS AtoN with message 21 for AIS basic information, messsage 6 for status report and message 12/14 for safety management.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.393-401
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• 2017

As the importance of software in various industry areas has been increased, the number of accidents related to software safety are growing up. The key industries such as railroads, aviation and medicine, recommend IEC 61508 and international safety standards for their own to achieve functional safety and reduce the issues caused by that. For equipment of ship navigation, there are not any particular standards or guidance which Korean users can introduce as considering software functional safety. This article defines the procedure and outcomes of the risk analysis in order to secure software functional safety in marine navigational equipment and applies them to an echo sounder as a case study.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.67-78
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• 2008

With the rapid development of wireless communication and mobile equipment, many applications for location-based services have been emerging. Moving objects such as vehicles and ships change their positions over time. Moving objects have their moving path, called the trajectory, because they move continuously. To monitor the trajectory of moving objects in a large scale database system, an efficient Indexing scheme to processed queries related to trajectories is required. In this paper, we focus on the issues of minimizing the dead space of index structures. The Minimum Bounding Boxes (MBBs) of non-leaf nodes in trajectory-preserving indexing schemes have large amounts of dead space since trajectory preservation is achieved at the sacrifice of the spatial locality of trajectories. In this thesis, we propose entry relocating techniques to reduce dead space and overlaps in non-leaf nodes. we present performance studies that compare the proposed index schemes with the TB-tree and the R*-tree under a varying set of spatio-temporal queries.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.134-140
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• 2021

This study relates to the development of a wearable device that can identify a personal location using low-power GPS and IMU based on energy harvesting. The energy harvesting technology using a piezoelectric device was applied for the development of personal location identification, and made it possible to acquire precise personal location data using GPS and IMU. As a result of the experiment, it was confirmed that GPS and IMU data were normally received. The personal location identification device can be prepared for an accident by identifying a personal location in a disaster area, etc., and the user will be able to use it easily regardless of time, place, and environment. It is expected that it can be used in various fields such as leisure and health care.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.217-225
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• 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 Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1515-1524
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• 2015

Recently, for the purpose of preventing the corrosion of a vessel, the electrical corrosion protection device that prevents the corrosions of the hull and the propeller is widely used. However, the electrical corrosion protection method artificially emits the current into the seawater around the hull using the power supply in order to make the hull and propeller be in the state of not being corrosion, so that electromagnetic field is generated outside the hull by the current emitted into the seawater. In this paper, the static and alternating constituents of the electromagnetic field generated in underwater outside the hull are analyzed and a countermeasure is investigated to reduce the strength of the electromagnetic field. In conventional shaft grounding system, the shaft potential is maintained above at least 100mV and the alternating current component constitutes more than 10% of the total current. However, in this paper, a control system was designed in order that the alternating current component and the shaft potential which generate electromagnetic field are maintained within 1% and 2mV respectively, and the performance was verified by simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2917-2923
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• 2015

In spite of a recent trend of container ships becoming larger in size, the current circumstance is that managing reefer containers marine transportation is being mostly dependent upon manpower. Particularly, in the case of bad weather or nighttime, reefer containers are not being monitored due to lack of safety device. For the purpose of reducing such risk, IMO is recommending a system using PLC but the system is not being used. In addition, they are still relying on manpower for control and reliability of freight in transit is decreasing due to lack of information during marine transportation for every subject related to freight as well as shipper. Accordingly, the purpose of this paper is to propose a real-time reefer container management system to effectively control all reefer containers widely being used across the world.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.410-418
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• 2000

In general, the experienced diver go into the water to find out Pan Shell which is spontaneously generated and brought up at the depth of 25-30 meters in the slime along the bank of an inlet of western and southern sea. However, this searching system has caused some problems in terms of economical efficiency and riskiness of diver. To overcome such problems and enhance the competence capability of fishermen, a new Pan Shell searching system is required. If an onboard searching system as a substitute of the way of diving into the deep water to identify the existence of Pan Shell is developed, it would be greatly beneficial to fishermen. The purpose of this research is to develop a new searching system of Pan Shell by making use of 50-200 Khz Ultra Sonic Signal, A/D Converter and computer process program. Based on the fact that Sonic Signal between the soft part of slime and the hard part of sand, pebble and Pan Shell is different, the possibility of this system have been approved in some degree by this time of research. However, to utilize this new system, further research on the establishment of data base and sample data is required. With the theoretical knowledge, the systematic research on the searching capability of Ultra Sonic Signal will be continued to identify the influence against the sea water subject. In this research, signal will be analyzed according to the influence range, power and sensitiveness of Ultra Sonic Generator. In addition, the radius of Ultra Sonic Signal will be included. The experimental field work will be executed at Nockdong, Pulkyo and other places well known as a habitat of Pan Shell.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.65-71
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• 2008

Recently, the research is progressing on the SWE(Sensor Web Enablement) platform of OGC(Open Geospatial Consortium) to provide the sensing data and moving pictures collected in a sensor network through the Internet Web. However, existed research does not deal with moving objects like cars, trains, ships, and person. Therefore, we present a method to deal with integrated sensing data collected by GPS device, sensor network, and image devices. Also, this paper proposes an integrated processing method for image and sensing data based on location in mobile sensor networks. Additionally, according to proposed methods, we design and implement the combine adapter. This combine adapter receives a contexts data, and provides the common interface included parsing, queueing, creating unified message function. We verity the proposed method which deal with the integrated sensing data based on combine adapter efficiently. Therefore, the research is expected to help the development of a various context information service based on location in future.