A Study on the Observation Days of Maritime Traffic Investigation

Sang-Lok Yoo,Seong-Book Park,Young-Soo Park,Jae-Yong Jeong 해양환경.안전학회 2015 海洋環境安全學會誌 Vol.21 No.4

본 연구는 관측일수에 따른 교통량의 신뢰성을 검증하고자 한다. 목포항의 1년간 선박자동식별장치(AIS) 자료를 사용하여 월별, 요일별, 시간별 변화지수를 비교한 후, 각 관측일수에 따른 최대표준오차를 산출하였다. 월별변화지수를 비교한 결과 9월달 1.11, 2월달 0.84로 나타나 9월달이 2월달 교통량 보다 약 32.1 % 많은 것으로 나타났다. 요일변화지수는 화요일 1.05, 일요일 0.92로 나타나 화요일이 일요일 교통량보다 약 14.1 % 많았다. 해상교통조사는 요일변화지수를 고려하여 최소 1주일 이상 실시하면 최대표준오차를 21 % 이내로 산출할 수 있다. 따라서 해상교통조사 관측시기에 따라 각 변화지수를 적용하여 교통량의 흐름을 반영한 연구가 뒷받침 되어야 하겠다. This study is to compare variation indexes by monthly, weekly and hourly using AIS data, which was collected for 365 days from January 1st to December 31st, 2013 at Mokpo Port and then, computed the maximum standard error by observation days. The comparison of monthly variation indexes showed that the monthly variation indexes for September and February were 1.11 and 0.84, respectively, in turn revealing that the maritime traffic in September was about 32.1 % larger than February. Also, the daily variation indexes for Tuesday and Sunday were 1.05 and 0.92, respectively, in turn revealing that the maritime traffic in Tuesday was about 14.1 % larger than Sunday. When the maritime traffic investigation is executed for at least 1 week in consideration of the daily variation index, it is possible to reduce the maximum standard error rate to be within 21 %. Therefore, if the maritime traffic investigation is made in the month and week with low maritime traffic, each variation index should be applied to reflect the actual maritime traffic.

Estimating Suitable Probability Distribution Function for Multimodal Traffic Distribution Function

Sang-Lok Yoo,Jae-Yong Jeong,Jeong-Bin Yim 해양환경안전학회 2015 海洋環境安全學會誌 Vol.21 No.3

The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.

Statistical Analysis of Ship Collision Accidents by Day and Night Times

Sang-Lok Yoo,Cho-Young Jung 해양환경안전학회 2018 海洋環境安全學會誌 Vol.24 No.3

Sunrise and sunset times differ depending on location and date. Previous studies conveniently but monotonously applied day and night times set up. This research defined the daytime and nighttime while considering the time of twilight according to the date and the location of ship collision accidents. Classifying the frequency of ship collision accidents with this standard, we conducted a chi-squared test for the difference between daytime and nighttime. The frequencies of ship collision accidents according to daytime and nighttime was compared by season, month, and time, and all of them showed statistically significant differences. The highest number of daytime ship collisions was 11.6 %, in June, and nighttime collisions peaked at 13.7 %, in December. The most frequent hour for daytime ship collisions was 0700h-0800h, at 10.2 %, and nighttime collisions peaked between 0400h-0500h, at 16.9 %. It is clear that the criteria used in previous studies cited was applied without any theoretical basis and likely only for the convenience of the researchers. It was found that results depend on what criteria are applied to the same research data. This study shows that statistical analyses of marine accidents, traffic volume, and congestion density should be carried out quantitatively while considering daytime and nighttime hours for each particular location and date.

Machine Learning-based Prediction of Ship Transit Time

Sang-Lok Yoo,Kwang-Il Kim,Keon-Myung Lee 한국콘텐츠학회 2020 한국콘텐츠학회 ICCC 논문집 Vol.2020 No.11

Estimating Suitable Probability Distribution Function for Multimodal Traffic Distribution Function

Yoo, Sang-Lok,Jeong, Jae-Yong,Yim, Jeong-Bin The Korean Society of Marine Environment and safet 2015 海洋環境安全學會誌 Vol.21 No.3

The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.

A Study on the Safe Route through the Analysis of the Density of the Gill Netters in the West Sea

Sang-Lok Yoo,Jong-Chul Jeong,Jae-Yong Jeong,Jeong-Bin Yim 해양환경안전학회 2016 海洋環境安全學會誌 Vol.22 No.5

본 연구는 서해안에서 상선의 어구 손괴로 인한 추진기 장애를 예방하기 위해 연안자망어선의 월별분포를 제시하였다. 분석 방법은 2014년 1년간의 어선위치발신장치 데이터를 이용하였다. 조업 해구도를 기준으로 경·위도 30′× 30′크기의 해구별 간격으로 격자를 설정하였다. 총 56개 해구를 대상으로 격자를 구성하였다. 연구 결과 밀도지수가 가장 높았던 194해구는 어구 손괴가 없었다. 반면, 밀도지수가 상대적으로 작은 193해구는 상선의 주 통항경로에 어구가 설치되기 때문에 손괴가 발생했다. 이 분석을 바탕으로 어구 손괴는 밀도지수에 비례하지 않고 상선의 주 통항경로에 따라 손괴위험이 존재하는 것으로 나타났다. 따라서 상선의 안전항해를 위해 5월부터 9월까지 위도 34.5° ~ 35.5°, 경도 125.67° ~ 126°를 항행경보구역으로 통보하면 추진기 장애와 어구손괴와 같은 해양사고를 예방할 것이다. 따라서 상선이 193해구와 203해구를 항해할 때는 안전한 항해를 위해 위도 34.5° ~ 35.5°, 경도 125.5° ~ 125.67°을 추천한다. This study attempted to present the monthly distribution of the inshore gill netters for the prevention of propeller failure caused by the damage of fishing gear by the merchant vessels in the West Sea. This study was conducted using the transmitting device of fishing location (V-Pass) data for 1 year in 2014. The grid intervals are 30 minute × 30 minute (latitude × longitude) based on the section of the sea. A total of 56 sections were analyzed by constructing a grid. The results revealed that the section no. 194 with the highest density index showed no fishing gear damage accident. But the section no. 193 with a relatively lower density index showed more frequent fishing gear damage accident. It is because the section no. 193 is included in the main route of the merchant vessels. Based on this analysis, it is found that the fishing gears are not damaged in proportion to density index but risk of damage exists according to the main routes of merchant vessels. Therefore, for the safe navigation of the merchant vessels, notifying the waters of 34.5° ~ 35.5° at latitude and 125.67° ~ 126° at longitude, as a navigational warning area from May through September, will prevent marine accident, such as propeller failure and fishing gear damage. Accordingly, when the merchant vessels navigate in the section no. 193 and 203, the area of 34.5° ~ 35.5° at latitude and 125.5° ~ 125.67° at longitude is recommended for the safe navigation.

A Study on Traffic Safety Assessments for Fishing Vessels Near the Southwest Sea Offshore Wind Farm

Sang-Lok Yoo,Jae-Yong Jeong 해양환경안전학회 2017 海洋環境安全學會誌 Vol.23 No.4

The purpose of this study was to analyze traffic safety assessments for fishing vessels near the southwest offshore wind farm. This study applied a collision model for safety assessment. It also involved a spatiotemporal analysis of vessels engaged in fishing to identify fishing hotspots around the offshore wind farm. This study used data from fishing vessel location transmission devices gathered over 1 year in 2014. As a result, in September, when the average number of vessels engaged in fishing is high, 62 ships were operating in fishing section 184-6 and 55 ships in section 184-6. In addition, in fishing sections 184-8 and 192-2, where an offshore wind farm was located, there were 55 and 38 ships operating, respectively. As the recovery period for a seaway near wind farm turbines is 55 years, it was determined that safety measures are required in order to reduce collision frequency while allowing fishing vessels to navigate through offshore wind farms. Meanwhile, the return period of Seaway B between the groups of generators considered was 184 years. A safety zone for offshore wind farms should be installed covering a distance of at least 0.3 NM from the boundary of turbines. Then, the collision return period was derived to be close to 100 years. Through this traffic safety assessment, it has been concluded that such measures would help prevent marine accidents.

Regression Analysis on the Relationship Between Elderly Ship Officers and Marine Accidents in Korea

Sang-Lok Yoo,Cho-young Jung 해양환경안전학회 2018 해양환경안전학회지 Vol.24 No.4

우리나라는 세계에서 가장 빠르게 고령화 사회로 접어들고 있다. 본 연구는 급속한 고령화 사회를 대비하기 위하여 고령 해기사와 해양사고와의 관계를 분석하여 고령화되어 가는 해기사 정책에 기초 자료를 제공하고자 한다. 수집한 데이터는 2006년부터 2016년 까지 11년간이며, 부원을 제외한 해기사만을 대상으로 현황 조사 및 회귀분석을 실시하였다. 연구결과 첫째, 60대 이상의 고령 해기사의 취업자 수는 지난 11년 동안 약 2.7배 증가하여 증가 추이 폭이 다른 연령대 보다 큰 것으로 조사되었다. 둘째, 해양사고로 징계를 받은 고령 해기사사는 약 2.6배 증가 추이를 보였다. 셋째, 고령 해기사는 비고령 해기사보다는 해양사고율이 약 1.5배 높은 것으로 나타났다. 넷째, 고령 해기사의 취업자 수와 징계자 수 간에 회귀분석을 실시한 결과, 고령 해기사 취업자 수가 고령 해기사 징계자 수를 설명하는 설명력의 정도가 75.1%로 나타났다. 고령화 사회가 신속히 진행될 수 있으므로 고령 해기사 면허 갱신 교육과 갱신 자격을 강화하는 규정 등의 정책이 필요할 것으로 판단된다. The Republic of Korea has a more rapidly aging society than any other country in the world. In order to prepare for the attendant challenges, this research provides basic data for policies related to aging ship officers, analyzing the relationship between elderly ship officers and marine accidents. The data used here spans 11 years, from 2006 to 2016, and the survey and regression analysis were conducted only on ship officers, excluding crew. As a result of this research, first, it was found that the number of employed ship officers older than 60 has increased 2.7 times over the past 11 years and the range of this increase was larger than for other age categories. Second, the number of elderly ship officers disciplined for marine accidents increased by around 2.6 times. Third, elderly ship officers had around 1.5 times the rate of marine accidents compared to non-elderly ship officers. Fourth, as a result of conducting regression analysis between the number of employed elderly ship officers and the number of officers disciplined, the degree of explanatory power of elderly ship officers for disciplined officials was 75.1%. Since our society will age quickly, policies such as license renewal education for elderly ship officers and regulation enforcing the quality of renewal will be needed.

A Study on Traffic Safety Assessments for Fishing Vessels Near the Southwest Sea Offshore Wind Farm

Yoo, Sang-Lok,Jeong, Jae-Yong The Korean Society of Marine Environment and safet 2017 해양환경안전학회지 Vol.23 No.3

The purpose of this study was to analyze traffic safety assessments for fishing vessels near the southwest offshore wind farm. This study applied a collision model for safety assessment. It also involved a spatiotemporal analysis of vessels engaged in fishing to identify fishing hotspots around the offshore wind farm. This study used data from fishing vessel location transmission devices gathered over 1 year in 2014. As a result, in September, when the average number of vessels engaged in fishing is high, 62 ships were operating in fishing section 184-6 and 55 ships in section 184-6. In addition, in fishing sections 184-8 and 192-2, where an offshore wind farm was located, there were 55 and 38 ships operating, respectively. As the recovery period for a seaway near wind farm turbines is 55 years, it was determined that safety measures are required in order to reduce collision frequency while allowing fishing vessels to navigate through offshore wind farms. Meanwhile, the return period of Seaway B between the groups of generators considered was 184 years. A safety zone for offshore wind farms should be installed covering a distance of at least 0.3 NM from the boundary of turbines. Then, the collision return period was derived to be close to 100 years. Through this traffic safety assessment, it has been concluded that such measures would help prevent marine accidents.

A Study on Maritime Traffic Characteristics according to Water Time(Multte)

Sang-Lok Yoo,Cho-Young Jeong,Jae-Yong Jeong 해양환경안전학회 2015 해양환경안전학회지 Vol.21 No.5

본 연구는 물때에 따른 교통특성을 분석하여 선박통항관리 개발에 필요한 자료를 제공하고자 한다. 목포항의 1년간 선박자동식별장치 자료를 사용하였다. 물때에 따른 교통량을 분석하기 위해 목포항의 1년간의 선박자동식별장치의 양력 데이터를 음력으로 변환한 후, 서해안의 구전 물때를 적용하였다. 연구 결과, 출항선박은 2-3물때 교통량이 7물때 보다 약 23-24% 많고, 입항선박은 12-13물때 교통량이 9물때 보다 약 29-33 % 많았다. 특히, 시간의 변화에 따른 물때별 변동지수는 sine 함수의 형태로 변화하였다. 본 연구는 물때에 따른 선박통항관리 개발에 필요한 기초자료로 활용될 수 있을 것으로 판단된다. This study seeks to analyze ships traffic characteristics according to water time in order to provide the necessary data for efficient traffic management development. To analyze maritime traffic volume according to water time, 1 year amount of solar calendar data were converted into lunar calendar, and then applied the traditional water time system of West Sea by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. As a result, it was found herein that the number of outbound ships was larger on the 2nd-3rd water times than the 7th water times by 23-24 %. And the number of inbound ships was higher on the 12th-13th water times than the 9th water time by 29-33 %. The hourly variation index of inbound and outbound ships according to time, in particular, was found to change in the form of sine function model. This study is expected to serve as a necessary basic material for development of maritime traffic management according to water time.