• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.23 no.4
• /
• pp.204-217
• /
• 2018

This study proposes a cost-effective method to monitor coastal environments using e-Navigation-implemented domestic and international ferries, and to analyze big data of records such as wind, temperature, salinity, waves, and currents that are gathered through e-Navigation system. First, we present the concept and architecture of e-Navigation operation system based on the General Information Center on Maritime Safety and Security. Then, the marine observation system that can be applied to ferries operating in our nation's territory is discussed. Analytical methods, such as spatio-temporal mixed effects model, ensemble method, and meshfree method, in handling real-time big data obtained by the e-Navigation observing system are then explained in detail. This study will support the implementation of the Korean e-Navigation project that focuses on the safety of small vessels such as coasters and fishing vessels.

• ALGAE
• /
• v.34 no.2
• /
• pp.71-90
• /
• 2019

A new encrusting red alga was found growing abundantly on glass debris items that drifted ashore along the coasts of Oregon and Washington. These included discarded fluorescent tubes, incandescent light bulbs, capped liquor bottles, and ball-shaped fishing-net floats. Field collections and unialgal cultures of the alga revealed that it consisted of two morphological phases: a young loosely aggregated turf and a mature consolidated mucilaginous crust. The turf phase consisted of a basal layer of globose cells that produced erect, rarely branched, uniseriate to multiseriate filaments up to $500{\mu}m$ long with closely spaced cells lacking pit-plugs. These filaments expanded in size from their bases to their tips and released single cells as spores. At maturity, a second phase of growth occurred that produced a consolidated crust, up to $370{\mu}m$ thick. It consisted of a basal layer of small, tightly appressed ellipsoidal-to-elongate cells that generated a mucilaginous perithallial matrix containing a second type of filament with irregularly spaced cells often undergoing binary division. At the matrix surface, the original filaments continued to grow and release spores but often also eroded. Individual cells, examined using confocal microscopy and SYBR Green staining, were found to contain a central nucleus, a single highly lobed peripheral chloroplast without a pyrenoid, and numerous chloroplast nucleoids. Morphological data from field and culture isolates and molecular data (rbcL, psbA, and SSU) show that this alga is a new genus and species which we name Viator vitreocola, "a traveller on glass."

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.1
• /
• pp.1-12
• /
• 2021

The International Maritime Organization (IMO) is promoting the introduction of e-Navigation that prevents maritime accidents by fusion of Information & Communication Technology (ICT) with ship operation technology. In Korea, Korean e-Navigation is also being developed for fishing vessels and small vessels sailing offshore, which are vulnerable to maritime accidents. However, for the successful development of Korean e-Navigation, it is necessary to develop an indicator that can evaluate the development performance so that the development performance that has been progressed so far can be evaluated and the development direction can be re-established. Therefore, this study attempted to develop an evaluation index tailored to the development goal of e-Navigation service centering on the collision accident, which is a major maritime accident. In this study, a collision accident evaluation index for e-Navigation service was developed by deriving and quantifying the root cause of maritime collision accidents using Root cause analysis(RCA) and fault tree analysis (FTA) techniques. This indicator is considered to be helpful in reducing maritime accidents as it is used as a development indicator for e-Navigation and an indicator for maritime collision accident analysis.

• Journal of the Korean Institute of Rural Architecture
• /
• v.25 no.1
• /
• pp.9-16
• /
• 2023

This study is on the formation and the development process of urban space by referring to the literature in Yeosu where is the important location in logistics & transportation and maritime since the Japanese colonial period. There are many factors and results of the development process in Yeosu by the opening port, railroads, loads and industries. The purpose of this study is to understand the characteristics of the formation process of urban space and the characteristics of physical space in Yeosu. The results are as follow; The urban formation and development process in Yeosu where was a small fishing village in the 1910s is largely divided into four processes. Formation: the population increased due to constructions such as of a railroad, a port, and roads and there were many reclamations around the center of the old city center in the Japanese colonial period. Stagnation: There was no urban development due to stagnation, war, and the Yeo-sun Incident. Expand: the industrialization of the Yeocheon Industrial Complex and Gwangyang Steel and other areas around Yeosu led to a surge in Yeosu's population. To cope with this, the city was expanded through three land readjustment projects and the development of large-scale residential complexes. Decline and Remodeling: Yeosu's urban space declined due to the decline of fisheries and the decrease in marine and railway logistics. And the expansion and improvement of the transportation network for hosting the Yeosu World Expo increased the accessibility of the old city center, transforming it into a tourist city using cultural heritage and nature.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2023.05a
• /
• pp.204-205
• /
• 2023

This study studied a prediction model for sending collision alarms for small fishing boats based on semi-supervised learning(SSL). The supervised learning (SL) method requires a large number of labeled data, but the labeling process takes a lot of resources and time. This study used service data collected through a data pipeline linked to 'intelligent maritime traffic information service' and data collected from real-sea experiment. The model accuracy was improved as a result of learning not only real-sea experiment data with labeling determined based on actual user satisfaction but also service data without label determined together.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.6
• /
• pp.450-459
• /
• 2023

According to Korea Maritime Safety Tribunal, there have been 14,100 maritime accidents from 2017 to 2021. Among those accidents, ship collision accidents have been up to 1,275 cases. But in the accidents relating to small ships like a fishing vessel, analyzing the causes of the accidents would depend on statements of the persons related because there is often no navigational data. But those statements can be incorrect and give rise to disagreements between them so that it causes conflicts with each other during the trial. So a replay system of ship collision accident (RESCA) has been developed in order to reproduce the ship collision accident by using AIS, V-PASS or radar data. But the reproduced trajectory of ship collision accident is needed to be verified because it can be unreasonable physically. So a method to verify the reproduced trajectory and collect the physical data on ship collision accident is newly designed by using free running test. In the RESCA, the accident is reproduced using the navigational data from the trajectory for a ship and measured from free running model test for the other ship at the same time. Through free running test, the behavior of the model ship is transformed from model scale into real scale. In order to check into the accuracy of the new method, free running model tests by using RESCA are carried out on the actual ship collision accidents.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.4
• /
• pp.535-544
• /
• 2015

Yield per recruit model is the most popular method for fisheries stock assessment. However, stock assessment using yield per recruit model can lead to recruitment overfishing as this model only considers the maximum yield per recruit without spawning biomass for reproduction. For this reason, spawning biomass per recruit model which reveals variations of spawning stock biomass per fishing mortality (F) and age at first capture ($t_c$) is considered as more proper method for stock assessment. There are mainly two methods for spawning biomass per recruit model known as age specific selectivity method and knife-edged selectivity method. In the knife-edged selectivity method, the spawning biomass per recruit has been often calculated using biomass per recruit value by multiplying the maturity ratio of the recruited age. But the maturity ratio in the previous method was not considered properly in previous studies. Therefore, a new method of the knife-edged selectivity model was suggested in this study using a weighted average of the maturity ratio for ages from the first capture to the lifespan. The optimum fishing mortality in terms of $F_{35%}$ which was obtained from the new method was compared to the old method for small yellow croaker stock in Korea. The value of $F_{35%}$ using the new knife-edged selectivity model was 0.302/year and the value using the old model was 0.349/year. However, the value of $F_{35%}$ using the age specific selectivity model was estimated as 0.320/year which was closer to the value from the new knife-edged selectivity model.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.2
• /
• pp.166-179
• /
• 1985

The seasonal distribution and migration of flying squid, Ommastrephes bartrami (LeSueur), in the North Pacific were studied by means of mantle length, surface temperature, and catch and effort data of the Korean drift gillnet fishery from 1980 to 1983. The water temperature for the best fishing ranged from $15^{\circ}\;to\;16^{\circ}C$ in May through July and from $13^{\circ}\;to\;18^{\circ}C$ in August through January. High densities of flying squid were found in the thermal fronts with $18^{\circ}C$ isotherm in August and with $15^{\circ}C$ isotherm in September. The densities of flying squid were higher in the western region than in the eastern region in the North Pacific. The high densities of flying squid in the northwestern Pacific were attributed to the high gradients of oceanographic properties in the region. Migration models for flying squid were hypothesized based on the monthly distributions of catch per unit net, mantle length compositions by statistical blocks, and the hydrographic features of the North Pacific. The large flying squid moved to the northern region and to the central Pacific region earlier than the small sized group in the northward migration period (from June to August). Flying squid begin the reverse southward migration from the Subarctic Frontal Zone in autumn with onset of cooling and the development of Oyashio Current. The large sized group starts their southward return migration from more northern waters than the small sized group but the former moves past the later ana reaches the spawing ground first.

• Korean Journal of Social Welfare
• /
• v.61 no.1
• /
• pp.323-357
• /
• 2009

This study illuminates the mechanism of life course on labor status of old age complementing the limits of labor status hypothesis of old age and model of statues attainment and combining them. The main results from this analysis are summarized in four points. Firstly, older men mostly engaged in agriculture, forestry and fishing industry or low-class occupations. A very small portion held high level or professional occupations. Regular full-time employees or employers were only 4.4% while, about 70% of older employees were temporal employees or self-employed. This shows that the elderly affluence hypothesis which alleges that most older men maintain high level occupations, applies to only a few. The second finding is that wealth differentials are sizable: about 20% of older workers own less than 50 million won, while 9.3% possess more than 600 million won. Therefore, it is not safe to claim that most people have accumulated enough wealth for old age according to the elderly affluence hypothesis. This gap being mainly reflected by education level, suggests that the model of status attainment is appropriate as wealth accumulation hypothesis. Thirdly, educational level determined not only lifetime careers, but also labor status of old age. Fourthly, using path analysis, the last finding is that education had effect on labor status of old age through lifetime career and wealth. That is, old men who have low education level had unstable lifetime career and own less wealth. They work in low income job, low social occupations and unstable occupation type in old age. This shows that life inequality continues until old age. Therefore, the inequality of education opportunity, spread of part-time work and small scale self employees should be discouraged. Furthermore, related policy should be provided in order to prevent being caught in unstable work.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.237-250
• /
• 2021

This study analyzed 'how the elderly's sexual relations and marital intimacy affect the elderly's life satisfaction'. Interviews and visits were conducted for 11 days targeting 309 elderly people aged 65 years or older. As a result of the analysis, 51% were male, 49% were female, and 84.7% were in their 60s and 70s. Approximately 60.1% of them were religious, of which 24.7% were protestants. In the region, 42.9% lived in rural and fishing villages. The percentage of those who answered that their health status was above average was 87.6%. Regarding the frequency of sexual life, 41.4% of the respondents said they had sex once or twice a month. Males had a higher frequency of sexual life than females. A lower age, higher education, living in small and medium-sized cities, better health status, and higher income level were associated with a higher frequency of sexual life. The factors that showed a significant difference in sex life satisfaction were gender, region, and health status. Those with religion as Protestantism, residing in a small or medium-sized city or over, with better health and higher income levels were found to have higher life satisfaction. The satisfaction with sex life had a positive correlation with emotional intimacy (p<.01) and life satisfaction (p<.01). Based on the above results, the sexual life satisfaction of the elderly has a positive effect on life satisfaction, and emotional intimacy between spouses had a positive influence on life satisfaction.