• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.760-764
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• 2015

Wireless sensors, installed on machinery, and Time Division Multiple Access (TDMA) transmission make an ideal system for monitoring machine conditions in industrial plants because there is no need for electronic wiring. However, there has not yet been a successful field application of such a system, capable of continuously transmitting data at sample rates greater than 100 Hz. In this research, a TDMA network protocol capable of acquiring data from multiple sensors at sample rates greater than 100 Hz was developed for field application. The protocol was implemented in a single cluster-star topology network, and the system was evaluated based on the node number and transmission distance. Network simulator 2 (ns-2) was used for a real field simulation. Non-TDMA and TDMA protocol cases were compared using four sensor nodes. In the cases of 20-s and 40-s transmission times, there was little difference between the reception rates of the non-TDMA and TDMA systems. However, the difference was much greater when using a 60-s transmission time.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.651-658
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• 2016

As three sides of Korea are surrounded by the sea and it is geographically located at an intersect point for continental and maritime climate, the climate crisis and global warming factors that lead to large-scale natural disasters such as typhoons, floods, and tsunami as well as disasters and damage to humans are increasing due to rapid urbanization and industrialization. Therefore, this study measured the ability of people to cope with disaster in students studying emergency rescue who will play a central role in safety and casualty control in disaster areas in order to figure out the factors that will influence their overall ability. As a result, the following things were discovered: Those who had the experience of listening to information on how to cope in a disaster scored significantly higher in disaster coping scores than those who did not. In comparison with subjects who responded that they were not satisfied with their emergency rescue training at school, those who responded that they were satisfied with their education scored significantly higher in their disaster coping scores. In comparison with subjects who responded negatively to the questions on experience in emergency rescue training as an extracurricular program, those who responded affirmatively to the questions were evaluated as significantly higher in their disaster coping scores. This study suggests that specific strategies can be taken and are needed to improve the ability to cope with disasters in students who are studying emergency rescue.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.695-706
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• 2012

The purpose of this paper is to propose a service system for a digital hologram video, which has not been published yet. This system assumes the existing service frame for 2-dimensional or 3-dimensional image/video, which includes data acquisition, processing, transmission, reception, and reconstruction. This system also includes the function to service the digital hologram at the viewer's view point by tracking the viewer's face. For this function, the image information at the virtual view point corresponding to the viewer's view point is generated to get the corresponding hologram. Here in this paper, only a prototype that includes major functions of it is implemented, which includes camera system for data acquisition, camera calibration and image rectification, depth/intensity image enhancement, intermediate view generation, digital hologram generation, and holographic image reconstruction by both simulation and optical apparatus. The proposed prototype system was implemented and the result showed that it takes about 352ms to generate one frame of digital hologram and reconstruct the image by simulation, or 183ms to reconstruct image by optical apparatus instead of simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.647-654
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• 2016

Indoor localization based on visible-light communication using the received signal strength intensity (RSSI) has been widely studied because of its high accuracy compared with other wireless localization methods. However, because the RSSI can vary according to the inclination and azimuth of the receiver, a large error can occur, even at the same position. In this paper, we propose a visible-light communication-based 3-D indoor positioning algorithm using the Gauss-Newton technique in order to reduce the errors caused by the change in the inclination of the receiver. The proposed system reduces the amount of computations by selecting the initial position of the receiver through the linear least-squares method (LSM), which is applied to the RSSIs, and improves the position accuracy by applying the Gauss-Newton technique to the 3-D nonlinear model that contains the RSSIs acquired by the changes in the azimuth and inclination of the receiver. In order to verify the validity of the proposed algorithm in an indoor space with dimensions of $6{\times}6{\times}3m$ where 16 LED lights are installed, we compare and analyze the errors of the conventional linear LSM-based trilateration technique and the proposed algorithm according to the changes in the inclination and azimuth of the receiver. The experimental results show that the location accuracy of the proposed algorithm is improved by 82.5% compared to the conventional LSM-based trilateration technique.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.2
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• pp.128-136
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• 2012

Hybrid surveys using hydroacoustic and fish sampling gears such as trammel net, trap were conducted to investigate total biomass, distribution and dominant fish species of the demersal fishes in the marine ranching area (MRA) of Jeju. Four surveys were carried out in June, August, October and November using 38kHz quantitative echo sounder. Catch data using trammel net and trap were used to calculate biomass and to examine dominant fish species. Fish schools were mainly detected in the waters of 20 meters below and around Chagwido waters. By the result of fishing experiments, fish species living in MRA of Jeju were about 40 species, dominant fish species of a detectable fish such as Family Sparidae and Family Monacanthidae etc. were identified 59.4~68.8% of total biomass. Based on the hydroacoustic data, fish length-weight function and target strength information, mean density of the demersal fish estimated were as follows; 0.88g/$m^2$ on June, 1.12g/$m^2$ on August, 1.35g/$m^2$ on October and 1.18g/$m^2$ on November. An estimated average biomass in MRA of Jeju was founded 20.5 tons in 2007, 20.6 tons in 2008, 23.0 tons in 2009, 25.9 tons in 2010. The results showed that biomass of MRA is getting increased slowly. Therefore the hybrid survey method using hydroacoustic and fish sampling gears is assured an effective biomass survey in the waters of mixed species.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.313-319
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• 2007

Long term wave climate of both extreme and operational wave height is essential for planning and designing coastal structures. Since the availability of the field wave data for the waters around Korean peninsula is limited to provide a reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. In this paper, a set of deep water wave data obtained from KORDI(2003) were analyzed for extreme wave heights. These wave data at 67 stations off the Korean coast from 1979 to 1998 were arranged in the 16 directions. The probability distributions considered in this research were the FT-I and Weibull distribution. For each of these distributions, the method proposed by Goda(2004) was applied to estimate the parameters. For judgment of best fitting, MIR criterion proposed by Goda and Gobune(1990) was used. FT-I distribution which best fits to the 886 data, while Weibull(k=0.75) 81 data, Weibull(k=1.00) 105 data.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.397-402
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• 2014

In June 1992, Convention on Biological Diversity (CBD) was concluded by 158 countries in Rio de Janeiro. And now, 194 member nations are participating in discussions for their own profit. Recently, Nagoya Protocol regarding Access to genetic resources and Benefit-Sharing (ABS) was approved and took effect from October $12^{th}$, 2014. Thus, it is important to understand the impact of CBD and ABS functioning on researchers studying marine biodiversity. Until now, in the previous Conference of the parties to the Convention on Biological Diversity, the interest towards researching marine and marine living resources was relatively low, and accordingly, the discussions regarding marine and marine living resources were delayed. However, in the $12^{th}$ Pyeongchang Conference of the Parties to the Convention on Biological Diversity, the arguments concerning Ecologically or Biologically Significant marine Areas (EBSA) and the other marine related issues were discussed. Although, South Korea has not yet officially joined Nagoya Protocol, however the consultations in regard to Prior and Informed Consent (PIC), Mutually Agreed Terms (MAT) and Global Multilateral Benefit-Sharing Mechanism (GMBSM) were discussed. We belive that as a possessing nation of biological resources, South Korean government authorities should revise their management systems protocol and regulations concerning domestic biological resources, in order to strengthen the information system and help academia and industry to utilize the biological resources abroad easily and effectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.241-247
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• 2012

The national geodetic reference frame of Korea switched to the International Terrestrial Reference Frame (ITRF) in 2003. In order to study the land area changes, we calculated the entire land area of Korea using the administrative boundaries of census data provided by Statistics Korea. The standard transformation procedure by the National Geographic Information Institute (NGII) was followed. The Transverse Mercator (TM) projected coordinates were transformed into the GRS80-based world geodetic reference frame, and the ellipsoidal and the projected areas were calculated. The provinces that range over two projection origins were divided into two polygons and projected using appropriate origins. After the transformation, all boundaries were shifted in the northwestern direction, resulting in a decreased area of $1.36km^2$ (about 0.0013%) on the projected plane. Moving the boundaries into a high latitude area cancels out the effect of the enlarged ellipsoid. In addition, the rate of change shows that a higher-latitude province is more sensitive to the shift of the boundaries. The data by Statistics Korea is significantly different from those of the Ministry of Land, Transport and Maritime Affairs (MLTM), thus it is urgently recommended that the data are integrated and unified.

• Journal of Science Education
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• v.34 no.1
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• pp.84-92
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• 2010

We analyzed learning materials from web sites of the Ministry of Environments, the Ministry of Land, Transport and Maritime Affairs and Korea Energy Management Corporation to help people to develop and utilize web-based multimedia teaching materials. The contents of web-based multimedia teaching materials for environmental educations were generally concentrated in 304 cases of natural environments (22.1%), 250 cases of environmental contaminations (16.5%) and 187 cases of environmental preservation plans (12.4%). It did not significantly deviate from traditional teaching-learning contents being conducted focusing on environmental pollutions of the past. The types of web-based multimedia teaching materials for environmental educations were 934 cases of teaching plans (61.8%), 156 cases of documentaries (10.3%) and 128 cases of e-text information (8.5%). The web-based multimedia teaching materials by school-levels showed that there were 796 for primary schools (35.3%), 588 for middle schools (26.1%) and 320 for high schools (14.2%). It also showed that environmental education with similar contents were provided even in advanced schools. Therefore, it is believed that there needs development of various types of teaching materials while the fields of environmental education contents are covered with connectivity according to school-levels.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.163-170
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• 2018

The purpose of this study is to describe quantitatively the characteristics and the structure of the Act on the development, management, etc. of Marinas (the Marinas Act) by analysing its provisions using semantic network analysis. The method of semantic network analysis has its advantages in overcoming limitations of the traditional content analysis method, as it is easy for the user to understand the structure and the shape of a network by figuring out the structural network among words. The object of the analysis is the full text of Marinas Act recently revised from Chapters 1 to 4, while partial analysis is carried out respectively for each chapter from Chapters 2 to 4. The structural characteristic of the Marinas Act shows that the act focuses on the development of marinas, as its main goal is interpreted to set up hardwares and to construct facilities rather than to promote the marina industry itself. Even though some clauses for human capital development and business development are included, they are of less importance compared to the development of marina facilities. This study provides some basic information on the structural characteristics of the current act, which can be referred to in subsequent studies. In the future, it also needs to be complemented through comparative analysis with government policy outcomes and performance of diverse analytical approaches.