• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.328-335
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• 2009

Phase variance of the acoustic signals has to be investigated with the research of the medium, because the phase of the acoustic signals carries the information of the medium. The phase compensation of the received signals is required for the signal processing of SAS (Synthetic Aperture Sonar) and underwater communication. In this paper, the phase variance of the acoustic signals was studied depending on the micro-scale-turbulence of ocean. The turbulence strength of the locally isotropic and homogeneous turbulence was calculated, and the phase variance affected by the turbulence strength was computed along the ray paths. The CTD and ADCP data were acquired from a buoy system near the Mukho port in the East Sea of Korea and the ray paths were calculated by the Bellhop algorithm. As a result, the turbulence strength was mainly determined by the variation of temperature and flow speed, changing the phase variance of the received signals. Hence, we thought the phase variance should be considered in the sonar operating system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.541-550
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• 2014

This paper describes a multi-scale user interaction based tiled display visualization system using multiple input devices for monitoring and analyzing Geostationary Ocean Color Imager (GOCI) observation satellite imagery. This system provides multi-touch screen, Kinect motion sensing, and moblie interface for multiple users to control the satellite imagery either in front of the tiled display screen or far away from a distance to view marine environmental or climate changes around Korean peninsular more effectively. Due to a large amount of memory required for loading high-resolution GOCI satellite images, we employed the multi-level image load technique where the image was divided into small tiled images in order to reduce the load on the system and to be operated smoothly by user manipulation. This system performs the abstraction of common input information from multi-user Kinect motion and gestures, multi-touch points and mobile interaction information to enable a variety of user interactions for any tiled display application. In addition, the unit of time corresponding to the selected date of the satellite images are sequentially displayed on the screen and multiple users can zoom-in/out, move the imagery and select buttons to trigger functions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.902-909
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• 2023

This study evaluated the performance test of a small-sized LTE-Maritime(LTE-M) transceiver that was developed and promoted to expand the use of intelligent maritime traf ic information services led by the Ministry of Oceans and Fisheries with the aim of supporting the prevention of maritime accidents. Accoriding to statistics, approximately 30% of all marine accidents in Korean water occur with ships weighing less than 3 tons. Therefore, the blind spots of maritime safety must be supplemented through the development of small-sized transceivers. The small transceiver may be used in fishing boats that are active near coastal waters and in water leisure equipment near the coastline. Therefore, verifying whether sufficient performance and stable communication quality are provided is necessary, considering the environment of their real usage. In this study, we reviewed the communication quality goals of the LTE-M network and the performance requirements of small-sized transceivers suggested by the Ministry of Oceans and Fisheries, and proposed a test plan to appropriately evaluate the performance of small-sized transceivers. The validity of the proposed test method was verified for six real-sea areas with a high frequency of marine accidents. Consequently, the downlink and uplink transmission speeds of the small-sized LTE-M transceiver showed performances of 9 Mbps or more and 3 Mbps or more, respectively. In addition, using the coverage analysis system, coverage of more than 95% and 100% were confirmed in the intensive management zone (0-30 km) and interesting zone (30-50 km), respectively. The performance evaluation method and test results proposed in this paper are expected to be used as reference materials for verifying the performance of transceivers, contributing to the spread of government-promoted e-navigation services and small-sized transceivers.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.525-532
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• 2021

In the ocean, it is difficult to separate the effects of one cause due to the multiple causes, but the self-organizing map can be analyzed by adding other factors to the cluster result. Therefore, in this study, the results of the clustering of sea level data were applied to sea surface temperature. Sea level data was clustered into a total of 6 nodes. The difference between sea surface temperature and sea level height has a one-month delay, which applied sea surface temperature data a month ago to the clustered results. As a result of comparing the mean of sea surface temperature of 140 to 150°E, where the sea surface temperature was variously distributed, in the case of nodes 1, 3, and 5, it was possible to find a meandering sea surface temperature distribution that is clearly distinguished from the sea level data. While nodes 2, 4 and 6, the sea surface temperature distribution was smooth. In this study, sea surface temperature data were applied to the clustered results of sea level data, but later it is necessary to apply wind or geostrophic velocity data to compare.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1089-1098
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• 2020

In this study, we propose a method to detect red tide Cochlodinium Polykrikoide using by machine learning and geostationary marine satellite images. To learn the machine learning model, GOCI Level 2 data were used, and the red tide location data of the National Fisheries Research and Development Institute was used. The machine learning model used logistic regression model, decision tree model, and random forest model. As a result of the performance evaluation, compared to the traditional GOCI image-based red tide detection algorithm without machine learning (Son et al., 2012) (75%), it was confirmed that the accuracy was improved by about 13~22%p (88~98%). In addition, as a result of comparing and analyzing the detection performance between machine learning models, the random forest model (98%) showed the highest detection accuracy.It is believed that this machine learning-based red tide detection algorithm can be used to detect red tide early in the future and track and monitor its movement and spread.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1201-1208
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• 2020

A mass of seawater with similar properties in the ocean is called a water mass, and the front is a sea area where two masses of different properties meet. The gradient algorithm is a method of extracting where the sea water temperature pixel changes rapidly assuming that the slope is large, and the place with the large slope is assumed to be a front. This method is able to process large amounts of satellite data at once. Therefore, in this study, we tried to find the front lines in the sea area around the Korean Peninsula by using a gradient algorithm. The study data used gridded sea surface temperature satellite data. The resolution was 1/4°, and the monthly average data from January 1993 to December 2018 were used. There were major five fronts representatively, China Coastal Front, South Sea Coastal Front, Kuroshio Front/ Kuroshio Extension Front, Subpolar Front and the Subarctic Front. As a result of comparing the distribution of front by season, more types of front were distributed in winter and spring than in summer and autumn, and the distribution range was wider.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.171-176
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• 2023

The purpose of this study is to analyze the introduction and use cases of Metaverse in the financial sector to learn lessons and implications. Let's take a look. The era of the metaverse is coming. The financial sector is pioneering the blue ocean market in a new era and working with the MZ generation. In order to expand contact points, we are very interested in the new business model, Metaverse, and are actively engaged in research and development. appear to be participating. In the case of finance, information is efficiently transmitted through metaverse, and customers It is predicted that the convenience of customers will be greatly improved by making it possible to use convenient services without visiting a branch. Additionally, by utilizing technologies such as AR and VR, we are trying to provide services linked to the metaverse in earnest. In addition, new financial services such as non-face-to-face asset management consulting services and brokerage services for funds through Metaverse Business models are also expected to be created. It is still in its infancy, and it is currently in its infancy, Metaverse is being used for educational purposes.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1249-1258
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• 2022

Marine debris is defined as a substance that is intentionally or inadvertently left on the shore or is introduced or discharged into the ocean, which has or is likely to have a harmful effect on the marine environments. In this study, the detection of marine debris and the analysis of the amount of change on marine debris were performed using the object detection method for an efficient method of identifying the quantity of marine debris and analyzing the amount of change. The study area is Yuho Mongdol Beach in the northeastern part of Geoje Island, and the amount of change was analyzed through images collected at 15-minute intervals for 32 days from September 12 to October 14, 2022. Marine debris detection using YOLOv5x, a one-stage object detection model, derived the performance of plastic bottles mAP 0.869 and styrofoam buoys mAP 0.862. As a result, marine debris showed a large decrease at 8-day intervals, and it was found that the quantity of Styrofoam buoys was about three times larger and the range of change was also larger.

• Journal of the Korean Geographical Society
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• v.38 no.3
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• pp.400-412
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• 2003

It is now widely recognized that new Information and Communication Technologies (ICTs) have been changing the way tv which firms conduct their businesses. Examples are the application of enterprise resources planning (ERP) and business process reengineering (BPR) to increase the efficiency of internal resources management, adoption of Business-to-Business e-commerce (B2B e-com) to integrate supply chain, and invention of new marketing channels such as Business-to-Customer (B2C) e-com. These new ways of conducting businesses are believed to help firms to reduce transaction costs and increase productivity. As a result, new ICTs have played an important role in recent growth of many small firms into multi-functional and multi-product corporations and in their spatial expansion towards internationalization as well. This paper takes Haier in China as a case to study the role of new ICTs in the growth of firms and reveal how the new technologies have facilitated the expansion of Haier into a transnational corporation (TNC) by examining the internationalization process of the firm in relation to its adoption of new ICTs in the period from 1990 to 2002. The study reveals that the adoption of new Ins has helped Haier to integrate its functional units located in dozens of places across the world, which is essential to the internationalization of a firm, and to link closely together its worldwide suppliers and customers to achieve just-in-time (JIT) production and delivery. As such, the authors of the paper argue that, without the facilitation of new ICTS, Haier could not have developed into a TNC in less than ten years.It is now widely recognized that new Information and Communication Technologies (ICTs) have been changing the way tv which firms conduct their businesses. Examples are the application of enterprise resources planning (ERP) and business process reengineering (BPR) to increase the efficiency of internal resources management, adoption of Business-to-Business e-commerce (B2B e-com) to integrate supply chain, and invention of new marketing channels such as Business-to-Customer (B2C) e-com. These new ways of conducting businesses are believed to help firms to reduce transaction costs and increase productivity. As a result, new ICTs have played an important role in recent growth of many small firms into multi-functional and multi-product corporations and in their spatial expansion towards internationalization as well. This paper takes Haier in China as a case to study the role of new ICTs in the growth of firms and reveal how the new technologies have facilitated the expansion of Haier into a transnational corporation (TNC) by examining the internationalization process of the firm in relation to its adoption of new ICTs in the period from 1990 to 2002. The study reveals that the adoption of new Ins has helped Haier to integrate its functional units located in dozens of places across the world, which is essential to the internationalization of a firm, and to link closely together its worldwide suppliers and customers to achieve just-in-time (JIT) production and delivery. As such, the authors of the paper argue that, without the facilitation of new ICTS, Haier could not have developed into a TNC in less than ten years.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1822-1829
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• 2016

DGPS Reference station is established in Korea for improvement of GPS navigation accuracy and needs of integrity. Recently, DGPS stations provide user positioning information on land as well as ocean. However, this paper investigated visibility and interference environment for performance degradation of Chung-ju DGPS reference station. In case of Young-do reference station, visibility and interference environment were satisfied with reference standard. In case of Chung-ju reference station, visibility was satisfied with 7 degree elevation angle. However, interference environment was not satisfied with reference standard of -50dBm. This paper proposed time differential measurement analysis method excluding error of signal noise for analyzing measurement error. Chung-ju reference station measurement analysis result is three times the error than on Young-do in Dec, 2015. In addition, this paper has confirmed measurement performance degradations because of reference station equipment problem. Future study will be carried out performance analysis of 17 DGPS reference station.