• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.462-469
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• 2023

In this study, we propose a method for evaluating the risk of collision between ships to support determination on the risk of collision in a situation in which ships encounter each other and to prevent collision accidents. Because several uncertainties are involved in the navigation of a ship, must be considered when evaluating the risk of collision. We apply the Dempster-Shafer theory to manage this uncertainty and evaluate the collision risk of each target vessel in real time. The distance at the closest point approach (DCPA), time to the closest point approach (TCPA), distance from another vessel, relative bearing, and velocity ratio are used as evaluation factors for ship collision risk. The basic probability assignments (BPAs) calculated by membership functions for each evaluation factor are fused through the combination rule of the Dempster-Shafer theory. As a result of the experiment using automatic identification system (AIS) data collected in situations where ships actually encounter each other, the suitability of evaluation was verified. By evaluating the risk of collision in real time in encounter situations between ships, collision accidents caused by human errora can be prevented. This is expected to be used for vessel traffic service systems and collision avoidance systems for autonomous ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.177-187
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• 2023

The Ship Safety Act prescribes matters necessary for the maintenance of seaworthiness and safe navigation of ships. In this regard, Article 10 of this Act requires shipowner to undergo occasional survey if he/she wants to temporarily change intends to modify the details entered in a ship survey certificate. Such measures are in accordance with the maintenance of the state of the ship after the ship inspection under Article 15 of this Act, and this Act includes "harbor construction work ship" under Article 39 Paragraph (1) of the Harbor Act. However, although the harbor construction work ship originally showed the same operating system as the barge, it was not applied to the Ship Safety Act and was registered and surveyed under the Construction Machinery Management Act. Then "Seokjeong No. 36" sinking accident in Ulsan on December 14, 2012, led to the amendment of the Harbor Act in 2016, and considering the fact that it was added to the Ship Safety Act and applied, there is a realistic limit to applying all the regulations stipulated in the Ship Safety Act to the harbor construction work ship. Accordingly, this study discusses the work characteristics through concept, registration, work area, survey regulations, application case of temporary alteration etc. of harbor construction work ships and controversial issues related to the scope of application of the Ship Safety Act of actual harbor construction work ships, and also the appropriate scope of "temporary alteration" among temporary inspections prescribed in Article 10 of the Ship Safety Act in consideration of the legislative purpose of incorporating harbor construction work ships into the survey subject to the Ship Safety Act in accordance with the revision of the Harbor Act.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.33-33
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• 2021

예측하기 어려운 복잡한 기후 변화로 인해 수자원 관리측면에서 다양한 방법을 도입하여 해결할 수 있는 방안이 국가적 주요 관심사로 다루어지고 있다. 따라서 투입인력과 소요시간 절감, 장비와 인력진입 불가지역에 대한 정보획득, 높은 공간해상도, 항공측량 대비 높은 경제성 등 다양한 장점의 드론을 이용한 하천지형 특성별 수리특성 분석방안이 필요하다. 본 연구에서는 성연천 하류부지역을 대상으로 위성항법시스템(Global Navigation Satellite System, GNSS) 측량 지형성과와 드론측량(Drone) 지형성과를 지상에 설치된 CHP(Check Point) 좌표 값을 확인하여 두 지형의 정확도를 비교하였으며 HEC-RAS 모형을 이용하여 빈도별 수리특성을 비교 산정하였다. 본 연구는 성연천 하류 480m구간을 선정하고 GNSS를 이용한 실측지형자료와 GCP(Ground Control Point)를 얻기 위해 정확도 검증을 실시하였으며 위성항법시스템(GNSS) 측량과 DRONE RGB측량의 CHP(Check Point) 오차를 비교하여 정확도를 검증하였다. 오차 값이 확인된 위성항법시스템(GNSS)을 이용하여 가상기준점을 선정하고 RTK 모바일스테이션을 설치하여 DRONE LIDAR측량을 통해 지형자료를 취득하였으며 얻어진 지형자료를 HEC-RAS를 통해 입력 후 성연천 하천기본계획에 제시되어진 조도계수와 빈도별 홍수위를 적용하여 연구구간 480m에 대해 100년 빈도의 결과 값을 비교 검토하였다. 100년 빈도 계획 홍수량 조건의 하상과 한계수위의 차에서 위성항법시스템(GNSS) 측량 지형자료를 기준으로 평균수위 측정오차는 드론 RGB 측량 지형자료 0.460m, 드론 LIDAR 측량 지형자료 0.260m의 결과를 얻었으며 동일 조건 흐름하의 평균유속에서 위성항법시스템(GNSS) 측량 지형자료를 기준으로 평균유속 측정오차는 드론 RGB 측량 지형자료 0.40m/s, 드론 LIDAR 측량 지형자료 0.36m/s의 결과를 얻었다. 통수 단면적의 비교 결과는 위성항법시스템(GNSS) 측량 지형자료를 기준으로 드론 RGB 측량 지형자료 전체 단면의 평균오차는 20.20m², 드론 LIDAR 측량 지형자료 전체 단면의 평균오차는 21.68²의 결과를 얻었으며 이상에서와 같이 홍수위와 평균유속, 통수 단면적의 측정오차 비교 결과를 종합할 때 통수 단면적 측정결과는 위성항법시스템(GNSS) 측량과 드론 RGB 측량의 차이가 적었으나 계획 홍수량 조건의 하상과 한계수위 차이와 동일조건 흐름하의 평균유속에서 위성항법시스템(GNSS) 측량과 드론 LIDAR 측량의 차이가 적은 것으로 나타났다. 그리고 통수용량(capacity)(m³) 비교에서는 위성항법시스템(GNSS) 측량을 기준으로 드론 RGB 측량은 약 7644m³, 드론 LIDAR 측량은 약 7547m³의 차이를 보여 드론 LIDAR를 이용한 결과가 가장 정확한 측정방법으로 추천할 수 있음을 확인하였다.

• Journal of Korean Port Research
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• v.4 no.1
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• pp.33-43
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• 1990

우리나라에서는 70년대 이후 컨테이너 수송체계가 도입되어 운영되어 왔으나 차량의 급격한 증가와 더불어 컨테이너 수송체계는 도시교통에 있어서 많은 문제를 야기시키는 것으로 논란이 되고 있다. 특히, 부산항은 우리나라 최대의 국제 무역항으로써 전 컨테이너 수송화물의 90%이상을 처리하고 있고, 또한 수출입항으로서 제 역할을 다하고 있으나 낮은 도로율(12.45%)과 산재해 있는 30여개의 Off-Dock CY로 인해서 도심을 통과하는 컨테이너 수송차량은 많은 교통문제를 유발시키고 있다. 본 연구는 1) 부산시에 산재해 있는 30여개의 Off-Dock CY에 이르는 주요 도로상에서 컨테이너 수송량의 신간별 분포에 따라 컨테이너의 운행시간대를 첨두 시간대, 비첨두 시간대 및 심야 시간대로 분류하여 각 시간대별 평균 수송 시간 및 교통 체증으로 인한 수송 지체수준을 확인하였고, 2) 컨테이너 전용부두로 부터 Off-Dock CY에 이르는 도시 고속도로 및 주요간선도로상에서의 수송시간 및 수송 지체수준을 비교 분석하였으며, 3) 마지막으로, 효율적인 컨테이너 수송체계를 위한 최적 수송시간대 및 도로체계를 제시할 수 있었다. 특히, 컨테이너 수송시간 및 지체수준은 각 운행 시간대에 따라 현저한 차이를 보이고 있었는데, 심야 시간대를 이용하여 컨테이너 수송을 할 경우에는 다른 시간대에 비하여 50%정도의 수송시간 절감효과를 기대할 수 있었으며, 도시 고속도로를 이용할 경우에는 도시 간선도로에 비하여 30%정도의 수송시간을 절약할 수 있었다. 따라서 도시지역의 교통체중을 완화시키기 위해서 심야 시간대에 보다 많은 컨테이너 수송차량이 이용할 수 있는 컨테이너 수송체계가 확립되어야 하고, 산재해 있는 Off-Dock CY를 몇개의 ODCY그룹이나 단지까지 컨테이너 전용 고속도로의 건설이 바람직하고 생각된다.리구에서 조사한 결과 $10^{-3}$ M MGBG 단독 처리구에서 에틸렌 생성량이 가장 높았으며, spermidine과 spermine의 함량은 가장 낮았다. 부정근 형성능이 다소 회복된 $10^{-3}$ M MGBG+ $10^{-5}$M spermine 혼합처리구에서의 에틸렌 생성량은 대조구보다는 다소 높게 나타났다. 부정근 회복능이 가장 높았던 $10^{-3}$ M MGBG+ $10^{-5}$ M spermine + $10^{-4}$ M Cocl$_2$ 혼합처리구에서 에틸렌 생성량은 가장 낮게 나타났으며, polyamine 함량은 가장 높게 나타났다.(Cyperaceae), 명아주과(Chenopodiaceae) 같은 풀들이 하구언(estuary)의 해안가에 주로 서식하였던 것으로 나타났다. 이 시기동안에 해양성조류인 와편모류와 담수성 조류가 동시에 다양하게 산출되는 것은 하구언 퇴적환경이었음을 잘 지시해 준다. 제II화분대(고도, 43.72{\sim}3.36\;m$)가 시작되면서 혼합림은 침엽수림으로 바뀌었으며, 낙엽활엽수들의 서식지가 2엽소나무로 대치되면서 침엽수가 주요 수종을 이루었던 것으로 나타났다. 아마도 이런 산림형태는 자연 기후환경변화 뿐만 아니라 인간간섭에 의해 나타난 결과로 생각된다. 이 시기에 경작식물인 벼과(Gramineae), 옥수수(Zea), 메밀(Fagopyrum)과 논밭의 뚝 등지 에서 서식하는 돼지풀(Ambrosia) 등이 처음으로 산출되는 것으로 보아 인간간섭이 행해졌음을 잘 뒷 받침해준다. 또한 담수성 조류는 변함없이 산출되는 반면, 해양성조류인 와편모류가 산출되지 않는 것으로 보아 해안환경에서 다소 멀 어진

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.149-156
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• 2024

The increased intelligence and speed of vehicle infotainment, whose main purpose was emergency and external communication, is showing the potential for application to various services such as navigation and autonomous driving. In particular, functionality for linking external devices and infrastructure is being strengthened due to advances in communication and networks. Under this trend, it is necessary to consider the direction of linkage with the cooperative intelligent transportation system (C-ITS) for advanced vehicle services and driving. In addition, in the case of automobiles, future vehicle development concepts are being established based on the concept of software-defined vehicles (SDVs) in line with the trend of electrification beyond telematics and infotainment advancements, and such SDV linkage must be considered at the same time. In this paper, we consider the future direction of ITS and SDV linkage based on analysis of vehicle infotainment structure. First, for this purpose, we analyze the existing vehicle infotainment structure and architecture, and also present the structure of the SDV linked to it. Based on this, analysis and implications are drawn on the possibility of applying and linking standard-based C-ITS services with SDV devices.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.97-107
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• 2024

Despite the rapid advancement in image recognition technology, achieving perfect digitization of tabular documents and handwritten documents still challenges. The purpose of this study is to improve the accuracy of digitizing the logbook by correcting errors by utilizing associated rules considered during logbook entries. Through this, it is expected to enhance the accuracy and reliability of data extracted from logbook through OCR programs. This model is to improve the accuracy of digitizing the logbook of the training ship "Saenuri" at the Mokpo Maritime University by correcting errors identified after Optical Character Recognition (OCR) program recognition. The model identified and corrected errors by utilizing associated rules considered during logbook entries. To evaluate the effect of model, the data before and after correction were divided by features, and comparisons were made between the same sailing number and the same feature. Using this model, approximately 10.6% of errors out of the total estimated error rate of about 11.8% were identified, and 56 out of 123 errors were corrected. A limitation of this study is that it only focuses on information from Dist.Run to Stand Course sections of the logbook, which contain navigational information. Future research will aim to correct more information from the logbook, including weather information, to overcome this limitation.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.201-248
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• 2015

In Korea the number of unlawful interference act on board aircrafts has been increased continuously according to the growth of aviation demand, and there were 55 incidents in 2000, followed by 354 incidents in 2014, and an average of 211 incidents a year over the past five years. In 1963, a number of states adopted the Convention on Offences and Certain Other Acts Committed on Board Aircraft (the Tokyo Convention 1963) as the first worldwide international legal instrument on aviation security. The Tokyo Convention took effect in 1969 and, shortly afterward, in 1970 the Convention for the Suppression of Unlawful Seizure of Aircraft(the Hague Convention 1970) was adopted, and the Convention for the Suppression of Unlawful Acts Against the Safety of Civil Aviation(the Montreal Convention 1971) was adopted in 1971. After 9/11 incidents in 2001, to amend and supplement the Montreal Convention 1971, the Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation(the Beijing Convention 2010) was adopted in 2010, and to supplement the Hague Convention 1970, the Protocol Supplementary to the Convention for the Suppression of Unlawful Seizure of Aircraft(the Beijing Protocol 2010) was adopted in 2010. Since then, in response to increased cases of unruly behavior on board aircrafts which escalated in both severity and frequency,, the Montreal Protocol which is seen as an amendment to the Convention on Offences and Certain Other Acts Committed on Board Aircraft(the Tokyo Convention 1963) was adopted in 2014. Korea ratified the Tokyo Convention 1963, the Hague Convention 1970, the Montreal Convention 1971, the Montreal Supplementary Protocol 1988, and the Convention on the Marking of Plastic Explosive 1991 which have proven to be effective. Under the Tokyo Convention ratified in 1970, Korea further enacted the Aircraft Navigation Safety Act in 1974, as well as the Aviation Safety and Security Act that replaced the Aircraft Navigation Safety Act in August 2002. Meanwhile, the title of the Aviation Safety and Security Act was changed to the Aviation Security Act in April 2014. The Aviation Security Act is essentially an implementing legislation of the Tokyo Convention and Hague Convention. Also the language of the Aviation Security Act is generally broader than the unruly and disruptive behavior in Sections 1-3 of the model legislation in ICAO Circular 288. The Aviation Security Act has reflected the considerable parts of the implementation of national legislation under the Beijing Convention and Beijing Protocol 2010, and the Montreal Protocol 2014 that are the modernized international conventions relating to aviation security. However, in future, when these international conventions would come into effect and Korea would ratify them, the national legislation that should be amended or provided newly in the Aviation Security Act are as followings : The jurisdiction, the definition of 'in flight', the immunity from the actions against the aircraft commander, etc., the compulsory delivery of the offender by the aircraft commander, etc., the strengthening of penalty on the person breaking the law, the enlargement of application to the accomplice, and the observance of international convention. Among them, particularly the Korean legislation is silent on the scope of the jurisdiction. Therefore, in order for jurisdiction to be extended to the extra-territorial cases of unruly and disruptive offences, it is desirable that either the Aviation Security Act or the general Crime Codes should be revised. In conclusion, in order to meet the intelligent and diverse aviation threats, the Korean government should review closely the contents of international conventions relating to aviation security and the current ratification status of international conventions by each state, and make effort to improve the legislation relating to aviation security and the aviation security system for the ratification of international conventions and the implementation of national legislation under international conventions.

• Journal of Intelligence and Information Systems
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• v.25 no.1
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• pp.85-107
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• 2019

Online consumers browse products belonging to a particular product line or brand for purchase, or simply leave a wide range of navigation without making purchase. The research on the behavior and purchase of online consumers has been steadily progressed, and related services and applications based on behavior data of consumers have been developed in practice. In recent years, customization strategies and recommendation systems of consumers have been utilized due to the development of big data technology, and attempts are being made to optimize users' shopping experience. However, even in such an attempt, it is very unlikely that online consumers will actually be able to visit the website and switch to the purchase stage. This is because online consumers do not just visit the website to purchase products but use and browse the websites differently according to their shopping motives and purposes. Therefore, it is important to analyze various types of visits as well as visits to purchase, which is important for understanding the behaviors of online consumers. In this study, we explored the clustering analysis of session based on click stream data of e-commerce company in order to explain diversity and complexity of search behavior of online consumers and typified search behavior. For the analysis, we converted data points of more than 8 million pages units into visit units' sessions, resulting in a total of over 500,000 website visit sessions. For each visit session, 12 characteristics such as page view, duration, search diversity, and page type concentration were extracted for clustering analysis. Considering the size of the data set, we performed the analysis using the Mini-Batch K-means algorithm, which has advantages in terms of learning speed and efficiency while maintaining the clustering performance similar to that of the clustering algorithm K-means. The most optimized number of clusters was derived from four, and the differences in session unit characteristics and purchasing rates were identified for each cluster. The online consumer visits the website several times and learns about the product and decides the purchase. In order to analyze the purchasing process over several visits of the online consumer, we constructed the visiting sequence data of the consumer based on the navigation patterns in the web site derived clustering analysis. The visit sequence data includes a series of visiting sequences until one purchase is made, and the items constituting one sequence become cluster labels derived from the foregoing. We have separately established a sequence data for consumers who have made purchases and data on visits for consumers who have only explored products without making purchases during the same period of time. And then sequential pattern mining was applied to extract frequent patterns from each sequence data. The minimum support is set to 10%, and frequent patterns consist of a sequence of cluster labels. While there are common derived patterns in both sequence data, there are also frequent patterns derived only from one side of sequence data. We found that the consumers who made purchases through the comparative analysis of the extracted frequent patterns showed the visiting pattern to decide to purchase the product repeatedly while searching for the specific product. The implication of this study is that we analyze the search type of online consumers by using large - scale click stream data and analyze the patterns of them to explain the behavior of purchasing process with data-driven point. Most studies that typology of online consumers have focused on the characteristics of the type and what factors are key in distinguishing that type. In this study, we carried out an analysis to type the behavior of online consumers, and further analyzed what order the types could be organized into one another and become a series of search patterns. In addition, online retailers will be able to try to improve their purchasing conversion through marketing strategies and recommendations for various types of visit and will be able to evaluate the effect of the strategy through changes in consumers' visit patterns.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.175-185
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• 2000

This paper described on a basic study to organize fishing vessel control system in order to control efficiently fishing vessel in Korean offshore. It was digitalized ARPA image on the fishing processing of a fleet of purse seiner in conducting fishing operation at Cheju offshore in Korea as a digital camera and then simulated by used VTMS. Futhermore, it was investigated on the application of FVTMS which can control efficiently fishing vessels in fishing ground. The results obtained were as follows ; (1) It was taken 16 minutes and 35 minutes to casting and hauling net in fishing processing respectively. The length of rope pulled by scout boat was 200m, tactical diameter in casting net was 340.8m, turning speed was 6kts as well. (2) The processing of casting and hauling net was moved to SW, NE as results of simulation when the current direction and speed set into NE, 2kts and SW, 2kts respectively. Such as these results suggest that can predict to control the fishing vessel previously with information of fishing ground, fishery and ship's maneuvering, etc. (3) The control range of VTMS radar used in simulation was about 16 miles. Although converting from a radar of the control vessel to another one, it was continuously acquired for the vector and the target data. The optimum control position could be determined by measuring and analyzing to distance and direction between the control vessel and the fleet of fishing vessel. (4) The FVTMS(fishing vessel traffic management services) model was suggested that fishing vessels received fishing conditions and safety navigation information can operate safely and efficiently.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.658-665
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• 2013

In this study, we measured particulate matter(PM) which emerged as the hot issue from the International Maritime Organization(IMO) and the exhaust emission using HANBADA, the training ship of Korea Maritime University. In particular, the PM was obtained with TEM grid. PM structure was observed by electron microscopy. And exhaust gases such as NOx, $CO_2$, and CO were measured using the combustion gas analyzer(PG-250A, HORIBA). The results of this study are as follows. 1) When the ship departed from the port, the maximum difference in PM emissions were up to 30 % due to the Bunker Change. 2) Under the steady navigation, emission of PM was $1.34mg/m^3$ when Bunker-A is changing L.R.F.O(3 %). And, at the fixed L.R.F.O (3 %), emission of PM was $1.19mg/m^3$. When the main engine RPM increased up to 20 % with fixed L.R.F.O(3 %), emission of PM was $1.40mg/m^3$. When we changed to low quality oil(L.R.F.O(3 %)), CO concentration from main engine increased about 16 %. On the other hand, when the main engine RPM is rising up to 20 %, CO concentration is increased more than 152 percent. These results imply that the changes of RPM is a dominant factor in exhaust emission although fuel oil type is an important factor. 3) The diameter of PM obtained with TEM grid is about $4{\sim}10{\mu}m$ and its structure shows porous aggregate.