• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.1019-1026
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• 2012

This paper presents a method for the identification of "edge observations" located on a boundary area constructed by a truncation variable as well as for the identification of outliers and the after fit of multivariate skew $t$-distribution(MST) to asymmetric data. The detection of edge observation is important in data analysis because it provides information on a certain critical area in observation space. The proposed method is applied to an Australian Institute of Sport(AIS) dataset that is well known for asymmetry in data space.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.366-368
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• 2022

지구온난화에 따른 우리나라 주변 환경의 변화와 최근 중국 불법 어선의 연근해 어업 자원의 고갈 등으로 인해 우리나라 연근해 어족자원을 보호할 필요성이 증대되고 있으며, 지속 가능한 어업을 위해서는 어획물의 종류와 양을 정확히 파악하고 불법 어업에 대한 철저한 감시 및 관리가 필요하다. 이러한 시공간적으로 다양하게 변하는 생태 및 어장 환경 정보와 선박에 대한 정보를 통해 해양관측과 위성 원격탐사를 동시에 이용함으로써 근해와 원양 생물자원 실태를 관측하는 것이 가능하다. 본 연구에서는 NOAA-20 위성의 VIIRS (Visible Infrared Imaging Radiometer Suite) DNB (Day & Night Band) 영상을 기반으로 추정한 야간 불빛 자료를 활용하고자 한다. DNB 불빛 영상은 낮은 조도의 불빛을 감지하여 그 정보를 보여 준다. 야간 불빛 자료에 포함된 구름 부분을 마스킹하기 위해 NASA의 신규알고리즘이 적용된JPSS-JRR-CloudMask 기술을 이용하였다. 이번 연구에서는 구름의 영향이 없는 날짜를 선별한 후 AIS 정보에서 어선의 정보를 추출하여 검증 자료로 사용하였다. 실제 선박의 정보를 이용한 위성 불빛 자료의 검증을 통해 위성자료의 신뢰성을 확보하고 향후 불빛과 선단 규모의 상관관계 분석 및 어선의 분포 경향 분석을 통하여 우리나라의 어장환경 분석에 활용 가능할 것으로 기대한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.79-88
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• 2006

The facility area occupies approximately 50% of the topographic landmarks playing an important role in the utilization of geographical information in various fields, and requires more up-to-date information than the framework data of other areas. However, the expression mode in the 1:5000 digital map, which is a primitive data used for the preparation of framework data in the facility area, limits the description of the information on buildings, and its revision/renewal term of 5 years makes it far from up-to-date or accurate. Therefore, this study aimed to analyze the problems and quality deteriorating factors that may occur in establishing the framework data on the basis of existing establishment process of them in the facility area, and improve the qualify of the framework data in facility area by upgrading the methods of quality improvement. Expanding the information on attributes and improving the accuracy of locations were proposed as ways to increase the degree of utilization of the framework data in the facility area. And as the methods of expanding the information on attributes, it was proposed to improve the accuracy of the information on attributes for the framework data in the facility area using the information on attributes in the 1:1000 scale maps, and also to diversify the information on attributes in connection with the LMIS and AIS. To improve the accuracy of the locations, analyses were made with the potential problems that may occur in the establishment process through an experiment on the framework data in the facility area based on 1:1,000 digital map, and the results were used to present an improved, optimum process.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.123-124
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• 2014

본 연구에서는 항해사의 경험적 위험 평가 지수를 바탕으로 특정 시간 항로 전 구간에 대한 해상교통 안전 평가 지수 모델을 개발하고자 한다. 이를 위해 항해사의 위험도 인식지수가 반영된 안전지수 평가 모델을 이용하여 특정항만 항로 전 구간에 대한 안전성 평가를 수치계산 하였다. 오사카 항 항만 내의 AIS data를 기반으로 시뮬레이션을 수행한 결과, 항만 내 항로 전 구간에 대한 안전지수의 변화를 계산할 수 있었으며, 특정항로, 특정 구간의 위험도 지수를 실시간으로 파악할 수 있음을 확인하였다. 향후 본 연구에서 제시된 모델을 이용하여 항만 내 통항 안전성 평가에 이용할 수 있을 것으로 기대된다.

• Annual Conference of KIPS
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• 2008.11a
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• pp.360-363
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• 2008

최근 관계형 데이터 스트림에서 키워드 검색에 관한 연구가 진행되고 있다. 키워드 검색을 통해 사용자는 시스템의 복잡한 내부 데이터 스키마나 질의언어에 대한 지식이 없이도 데이터 스트림에서 정보 검색이 가능하다. 하지만, 빈번하고 동적으로 변화하는 특성을 지닌 데이터 스트림에서 수행되는 연속 질의 처리를 위해서 보다 효과적인 질의 최적화 방안이 요구된다. 따라서, 우리는 본 논문을 통해 계층적 클러스터링을 이용하여 중간결과 공유의 최대화를 통한 질의 최적화를 방안을 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.190-193
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• 2015

The current sea route sign system based on an electronic marine chart only has a data manufacture specification for uses at ECDIS. Therefore, it has a limitation in expressing various sea route data and falls short of productivity as it is frozen to prevent being changed for a long time. Also, it cannot satisfy requirements from high tech such as lattice structure data and time series information. Currently, although it builds each independent operation system based S-57, it has been found that it is the most important requirement from consumers that the entire monitoring system can mutually interwork by standardizing and uniting formats of all protocols. In addition, current status information and alarm system is using AIS, TRS, WCDMA telecommunication and processing all the data after saving it into each different server. Lighthouse lantern which currently has used was utilized to do a performance test of a developed system. All of created data was trasmitted through the RS-232, It is clear that the data was received by a situation monitoring system. In addition, when the data was transmitted after saving in a database, same data was ordinarily received. In this thesis, we will implemented the status information and alarm system of Marine transportation facilities which is a sea route sign system based on S-63 electronic marine chart, S/W, after uniting each different protocol and making combined system.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.795-802
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• 2020

This study seeks to determine the effect of the application of accounting information system (AIS), internal control system, and human resource (HR) competency on the quality of local government financial statements (FS). This study uses agency theory and compliance theory. Agency theory is used to explain that there is a link between the society as the principal and the government as the agent. Compliance theory is a theory, which states that every agency is obliged to comply with regulations because the law-drafting authority has the right to dictate behavior. The population in this study were employees of the financial division of local government organizations in one of the districts in Central Java, Indonesia. The total samples in this study was 106 respondents. The data used are primary data taken from distributing questionnaires to respondents. The method of analysis used to test the hypothesis was multiple linear regression analysis. The results of hypothesis testing indicate that HR competency has an effect on the quality of FS; however, the application of AIS and internal control system has no effect on the quality of FS. The implication of this research underlines the importance of HR competency to improve the quality of local government FS.

• Journal of Navigation and Port Research
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• v.48 no.5
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• pp.409-417
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• 2024

Recently, various marine development initiatives, including offshore wind farms and marina port facilities, have been launched to enhance utilization of coastal waters. In addition, advancements in technologies for autonomous ships and wing-in-ground effect craft are progressing swiftly, increasing the complexity of maritime traffic. Accordingly, proactive policy development and research are needed to ensure safe navigation and decrease maritime accidents. The dynamic interplay between vessel traffic and geographical features in coastal waters necessitates spatio-temporal analysis. Factors such as currents, waves, and fog, along with vessel traffic services, play pivotal roles in managing maritime traffic. In this study, AIS data were used to quantitatively evaluate the distribution and utilization of maritime traffic in coastal waters using a grid cell approach. Furthermore, a suitability model for maritime traffic routes was developed, taking into account spatio-temporal operational and environmental characteristics. Results were compared to existing national maritime traffic route and offshore wind farm plans, providing valuable insights for the development of future maritime traffic networks.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.798-807
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• 2021

In the era of the fourth industrial revolution, Maritime Autonomous Surface Ship(MASS) are expected to emerge in the shipping industry. There has been much active research on collision avoidance systems regarding MASSs, but most of it has focused on merchant ships. A study of collision avoidance systems in fishing vessels is also essential, because Maritime Autonomous Surface Ships will encounter all type of vessels. In this study, the minimum passage distance between small-medium-sized fishing vessels and other vessels was investigated for the Ship's domain analysis. Based on the AIS data of Busan port and the adjacent area, the separation distances of fishing vessels were analyzed. The results indicated that as the speed of fishing vessels increased, the distance increased from 4L to 8L, and as length of the fishing vessels increased, the distance decreased from 10L to 6L. It is believed that the results of this study can be applied in the future to collision avoidance models for MASSs that reflect the domain of fishing vessels.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.367-375
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• 2023

This study developed a new distance metric for vessel trajectories, applicable to marine traffic control services in the Korean coastal waters. The proposed metric is designed through the weighted summation of the traditional Hausdorff distance, which measures the similarity between spatiotemporal data and incorporates the differences in the average Speed Over Ground (SOG) and the variance in Course Over Ground (COG) between two trajectories. To validate the effectiveness of this new metric, a comparative analysis was conducted using the actual Automatic Identification System (AIS) trajectory data, in conjunction with an agglomerative clustering algorithm. Data visualizations were used to confirm that the results of trajectory clustering, with the new metric, reflect geographical distances and the distribution of vessel behavioral characteristics more accurately, than conventional metrics such as the Hausdorff distance and Dynamic Time Warping distance. Quantitatively, based on the Davies-Bouldin index, the clustering results were found to be superior or comparable and demonstrated exceptional efficiency in computational distance calculation.