• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.324-332
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• 2018

We conducted a questionnaire survey to analyze the current status of the coastal composite fisheries, as well as the improvement point in designing a new type coastal composite fishing boat suitable for Korean fishing environments from April to August 2017. The questionnaire composed of 20 questions about the features of the coastal composite fishing boat and fishing work. The survey sites were selected to cover all parts of the country by considering the geographical position. The significance testing for the response results was accessed by ${\chi}^2$ test and ANOVA. The results revealed that more than half (59.1%) of the fishermen operated one day per voyage and operating alone topped with 22.5% in the number of crews, followed by 2 persons (20.3%) and 5 persons (22.1%). The navigation devices had a high rate of installation and GPS plotter ranked first in the devices. In addition, fish finder ranked first in fishing equipment, followed by net hauler. The most inconvenient work that they felt during the fishing operation was fish handing at 49.8% and other general fishing works like setting and hauling line, deck cleaning accounted for about 25%. The hardest work was the accident by ropes wrapped around propeller and the engine trouble came in second. The most inconvenient facilities to the present design of fishing boat was wheelhouse (76.7%), followed by fish hold (38.5%), and deck (35.1%). Furthermore, inconvenient points related to the movement of fishing gear, noise and vibration of engine, slippery deck and small fish hold exceeded 50%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.6
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• pp.343-349
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• 2014

In this paper, we propose a three-stage unambiguous tracking scheme for CBOC signals. We evenly divide composite binary offset carrier (CBOC) signal, which was adopted in the Galileo system developed by the European Union (EU), by width of BOC(6,1) signal pulse, and then, generate 12 partial correlations. Then, we generate an unambiguous correlation function by recombining the partial correlations with two kinds of operation. The proposed correlation function is narrower and higher than the conventional correlation functions. From simulation result, it is shown that the proposed correlation function offers a better signal tracking performance over the conventional correlation functions.

• Journal of the Korean Institute of Navigation
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• v.15 no.1
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• pp.67-93
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• 1991

In general, marine casualities take palace by the composite action of three elements such as waterway condition, vessel condition and man condition. One of the important characteristics of most marie casualties for small cargo vessels in maritime transportation of near-coastal and greater-coasting seas in that the same kind of casualities take place repeatedly in spite of the apprent causes, Because, it takes much time and effort for seamen to master waterway, vessel or operatin technique only to the practical and sensible level. In these days, with the development of our economy, our shiypping industry has grown and therefore the demand of marine officers has increased. This economic growth brought about undesirable situation like the evasion of seamen and frequent casualities of Korea vessels. These marine casualities are being caused mainly by the unskilfulness of operating technique as well as the bad waterway condition and ship's installation condition. Therefore, I conclude, in this paper, that the most efficient and economic preventing measures of marine casualities are seeking causes and removing them in advance under the close coperation system among all concerned parties.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.3
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• pp.107-114
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• 2015

Binary Offset Carrier (BOC) signal planned for future Global Navigation Satellite System (GNSS) provided better positioning accuracy and smaller multipath error than GPS C/A signal. However, due to the multiple side peaks in the auto-correlation function (ACF) of the BOC modulated signals, a receiver may false lock onto one of the side peaks in the tracking mode. This false lock would then result in a fatal tracking error. In this paper, we propose an unambiguous tracking method for composite BOC (CBOC) signals to mitigate this problem. It aims to reduce the side peaks of the ACF of CBOC modulated signals. It is based on the combination of traditional CBOC correlation function (CF) and reference CF of unmodulated pseudo- random noise code (PRN code). First, we present that cross-correlation function (CCF) with unmodulated PRN code is close to the secondary peaks of the traditional CBOC. Then, we obtain an unambiguous correlation function by subtracting traditional CBOC ACF from these CFs. Finally, the tracking performance for the CBOC signals is examined, and it is shown that the proposed method has better performance than the traditional unambiguous tracking method in additive white Gaussian noise (AWGN) channel.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.31-36
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• 2006

The evaluation of safety of simulated maneuvers is frequently analysed by so called goal line or point of interest. This paper is to suggest that regarding the results of simulation the goal analysis and in length analysis are investigated respectively and the availability of which is effective and is also to suggest closest distance to channel boundary at each ship's position, not centerline, as one of proximity measures.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.418-424
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• 2014

This paper aim; to develop the National R&D Information Navigation System(NRnDINS) that is convenient and easy to use by the researchers on the basis of information filtering and visualization by converging and integrating the three types of the contents, namely, paper, report and project at the stage of development of the information system An information system is developed by establishing ontology and RDF on the three types of contents, and by applying information filtering and semantic search technology after having created the prototype for the screen by reflecting the user needs analysis and information visualization elements surveyed at the previous stage of information service planning. In this paper, to make the measure for information filtering, R&D navigation index is prosed and implemented, and NRnDINS capable of integrated search of the R&D contents through information visualization is developed. Also, for the testing of the developed system, the preference survey for its design by 1m persons and usability test of the system by 10 users are performed The result of the survey on the preference for the design is affirmative with 85% of the subjects finding it favorable and the composite receptivity is good with the score of 87.2 the results of the usability test. However, it was also found that further development of the personalization functions is needed. It is hoped that the R&D navigation index of the proposed and implemented in this paper would present quantitative objectivity and will induce further development of other information filtering index of contents in the future.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.619-632
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• 2023

Purpose: The main function of INS (Inertial Navigation System) is to measure the position of an armed vehicle and its performance is confirmed through the positioning accuracy test of Korean Defense Standards (KDS). The current standards, however, do not provide clear test methods and the conditions for performing positioning accuracy tests. Accordingly, the purpose of this study is to develop a new method for positioning accuracy test which would be effective. Methods: In this study, a new INS positioning accuracy test method is suggested based on the analysis of test data collected through a statistical experiment known as central composite design. For the positioning accuracy experiment of K105A1, a self-propelled artillery, two factors of driving velocity and driving distance are considered. Results: Based on the analysis of experimental data, a regression model for the positioning error is fitted and the positioning accuracy test of INS is so developed to maximize the positioning error. The standard proximity rate is used as an additional test criterion to evaluate the performance level of INS. Conclusion: The proposed new positioning accuracy test for INS has the advantage of finding the nonconforming items effectively. It is also expected to be utilized for the other similar INS positioning accuracy tests.

• Journal of Korea Multimedia Society
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• v.4 no.2
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• pp.130-135
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• 2001

When a networked virtual reality system handles composite media audio and video as well as three dimensional computer graphics, the quality of the virtual space is greatly affected by the current available network, and end system resources. Even if the network can preserve a certain amount of resources, the required resources change dynamically according to the user\`s navigation of a large virtual space, and then it may decrease the quality of the virtual space. In this paper, a method for resource allocation is proposed and the proposed system copes with the deterioration of quality of virtual spaces in case that the starvation of system resources occurs. The experimental results show that the proposed method is efficient.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.295-304
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• 1997

For evaluation of maritime power, the attributes of sea power are identified in this paper by system analysis method. A many fundmental factors of sea power are selected by survey of the extensive and thorough literatures on maritime power. And the factors are classified into 11 standard attributes by cluster method. The 11 standard attributes are as follows: geographical condition, character of territory, character of the people, maritime will of the government, shipping power, navel power, shipbuilding power, fishing power, ocean research and development, dependence on seaborne trade, number of ocean population. As the sub-attributes of the standard attributes, 37 composite factors and some basic factors are defined through careful survey and discussion with some experts. As the result of this study, the maritime power is systematically identified as maritime power system. And it is realized that the evalution of maritime power system is the hybrid MADM problem with both quantitative and qualitative factors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.151-156
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• 2006

Accurate vessel traffic observation is indispensable to carry out vessel traffic management, design of vessel traffic route, planning of port construction, etc. In order to observe the vessel traffic accurately without many efforts such as the use of a ship or car equipped with special radar observation system and the preparation of observation staff, the authors have been developing completely automated remote radar/AIS network system covering the main traffic area in Tokyo Bay. The composite radar image observed at Yokosuka and Kawasaki radar stations with AIS information can be seen on web site of Internet. In addition to the development of radar/AIS observation system, the software to analyze observed vessel traffic flow has been developed. This software has various functions such as automatic tracking of ship's positions, automatic estimation of ship's size, automatic integration of radar image and AIS data, animation of ships' movements, extraction of dangerous ship encounters, etc. The configuration and functions of the developed remote radar/AIS network system are shown first in this paper. Then various functions of the software to analyze vessel traffic are introduced, and some analyzed results on the vessel traffic in Tokyo Bay are described demonstrating the effectiveness of the developed system.