• Journal of Advanced Navigation Technology
• /
• v.21 no.3
• /
• pp.306-311
• /
• 2017

In the future ubiquitous network, information will collect data from various sensors in the field. Since the sensor nodes are equipped with small, often irreplaceable, batteries with limited power capacity, it is essential that the network be energy-efficient in order to maximize its lifetime. In this paper, we propose an effective network routing method that can operate with low power as well as the transmission of data and information obtained from sensor networks, and identified the number of sensors with the best connectivity to help with the proper placement of the sensor. These purposes of this research are the development of the sensor middle-ware to integrate the maritime information and the proposal of the routing algorithm for gathering the maritime information of various sensors. In addition, for more secure ship navigation, we proposed a method to construct a sensor network using various electronic equipments that are difficult to access in a ship, and then construct a communication system using NMEA(the national marine electronics association), a ship communication standard, in the future.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.6
• /
• pp.744-750
• /
• 2014

The monitoring and abnormality warning of marine diesel engine are important to take appropriate responses for safety navigation. If maintenance engineers do not take appropriate response because of diagnosis mistakes, it will occur a nasty accident. Therefore, we need integrated monitoring and diagnosis system for supporting a diagnosis objectively. In this paper, we analyze time-series data which measured by real-time, monitor the changing of conditions and trends of the analyzed data. Furthermore, we design and implement a monitoring and diagnosis system for objective supporting of real-time diagnosis. When the integrated monitoring and diagnosis system is adopted, it can help to improve stability of marine diesel engine by providing abnormality warning alarm with appropriate responses.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.2
• /
• pp.278-287
• /
• 2011

NMEA 2000 protocol known as IEC 61162-3 of Multi-talker, Multi-listener and Plug and Play network communication has been adopted as standard network for SOLAS(Safety of Life at Sea) ship by IMO. This paper focuses on the implementation of FPGA and MicroBlaze for NMEA 2000 based gateway, which is able to convert NMEA 2000 protocol into various types of network protocol such as Ethernet, UART and USB using Vertex4-based ML401 board. Each communication module and the stack of NMEA 2000 are mounted on FPGA. To be able to receive each communication data, ML401 board is configured to handle required communication speed. PC based NMEA 2000 monitoring program is developed to verify that data on different networks are correctly converted each other in real time.

• Explosives and Blasting
• /
• v.25 no.2
• /
• pp.71-78
• /
• 2007

In many cases of underwater blasting in South Korea, the special blasting is mainly used for deepening harbor, installing gas pipes, or well blasting to build a bridge. The procedure of well blasting is almost same with shaft blasting, but the difference is that water is filled in before blasting. In case of deepening blasting under water, the first step like drilling, arranging explosives, and wire connection is done on a barge, then the next step such as charging and tamping is accomplished under water by expert divers. Therefore, underwater blasting needs precise and exact plan before blasting. In this paper, authors would like to introduce a case of underwater blasting for deepening the Busan new port with emulsion explosives and non-electric detonators in order to get some of 8,500TEU out sized container vessels entered into the port and to make safe. Considering environment and vibration, the blasting was controlled to minimized the damage to the lighthouse nearby. It will be great help to many other blasting sites where emulsion explosives and non-electric detonators are used for underwater blasting through this case.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.1
• /
• pp.32-39
• /
• 2011

When the laws about the security of ships are revised, or voyage conditions are changed, ship owners have converted rather than built new passenger ships including cruise ships recently. As conversion causes a lot of changes in principal dimension, structural strength, hydrodynamic performance, the number of passengers, and cargo capacity, detailed pre-review is needed. But any studies on conversion have not been carried out yet, this study investigated and analyzed the trend of consulting companies' reports (Delta Marine Report, 2005, 2008). As a result, it was found that lengthening conversion brought about the main changes in principal dimension, and performance. Also it was suggested that there be factors for consideration like hull scantling, hull form, and cutting point to minimize side effects when ship owners build ships having lengthening conversion in mind.

• Korean Journal of Construction Engineering and Management
• /
• v.11 no.4
• /
• pp.68-79
• /
• 2010

During the last two decades, several tele-operated and machine-vision-assisted systems have been developed in construction and maintenance area such as pavement crack sealing, sewer pipe rehabilitation, and excavation. In developing such tele-operated and machine-vision-assisted systems, trajectory plans are very important tasks for optimal motions of robots whether their environments are structured or unstructured. This paper presents an optimal trajectory planning algorithm used for a machine-vision-assisted automatic pavement crack sealing system. In this paper, the performance of the proposed optimal trajectory planning algorithm is compared with the greedy trajectory plans which are used in previously developed pavement crack sealing systems. The comparison is based on computational cost versus overall gains in crack sealing efficiency. Finally, it is concluded that the proposed algorithm plays an important role in productivity improvement of the automatic pavement crack sealing system developed.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.5
• /
• pp.445-452
• /
• 2017

The wing leading edge skin in this research is an essential structural factor for improving wings' aeromechanical functions, protecting the interior elements of the wings from external damage including birds, and navigating planes safely. The study compared and reviewed models manufactured for optimal light-weight wings of composite UAVs. It compared and investigated displacement forms of torsion loads through finite element analysis using MSC. Patran/Nastran. By confirming the improvement of light-weighting performance according to lamination type, thickness change and shape through torsion strength tests of each model, the research suggested the optimal light-weight wing leading edge skin for small composite UAVs.

• Journal of Distribution Research
• /
• v.4 no.3
• /
• pp.1-22
• /
• 2000

Many foreign freight forwarders make inroads into domestic markets. Korean freight forwarders are not competitive on th domestic logistics area because of higher customer services by foreign freight forwarders in Korea. The purpose of this research is to analyze degree of satisfaction on customer services attributes of freight forwarders in Korea, and to strengthen the competitiveness of customer services by Korea freight forwarders in contrast to foreign investment freight forwarders in Korea. The results of the research could be summarized as follows.: When freight forwarders are selected, the most important customer service attributes have been ranked in order with 'the accuracy management of shipping order' , the reasonable offers of freight rate' and 'the quick arrangement of vessels' when freight forwarders are selected.

• Journal of Navigation and Port Research
• /
• v.36 no.5
• /
• pp.363-370
• /
• 2012

Recently, International Maritime Organization has been developing e-navigation implementation strategy plan, which is focused on various services for vessel safety navigation. Then, different kinds of software will be developed in maritime area and with this, the quality issues are to be expected becoming more important. In this paper, we adopt software refactoring techniques to reduce the complexity of structure on source code level. It makes software program more effective to understand and modify, without any change of outward behavior. The existing AIS broadcast server program is used as an example for our trial, and calculating coupling and cohesion metric are introduced to analyze the refactoring effect, taking account of the maintainability of IEC/ISO9126 software quality standards.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.4
• /
• pp.476-485
• /
• 2014

PBL is a student-centered pedagogy in which students learn about a subject through the experience of problem solving. Marine engineer is the expert which supports the safe navigation and solves the problems could happen in independent situation as a ship. This study executed the fundamental study on the maritime training education for marine engineers using PBL. In this study, we conducted the survey on 56 students for 6 months using PBL in H university. The result showed the improvement on ability to solve the problems, interpersonal relationship, communication skill, synthetic thinking faculty and practical use of data but some students answered the complaint of the insufficient information and unacquainted learning method of PBL. This suggested the development and improvement plans for the maritime training education using PBL based on this fundamental study.