• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.459-468
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• 2022

Long-term data analyses and bioassay experiments were conducted to assess limiting nutrients in Cheonsu Bay and Taean sea. First, long-term nutrient data (2004-2016) provided by the National Water Quality Monitoring Network were used to assess potential limiting nutrients. Analysis of the long-term data showed that the dissolved inorganic nitrogen/dissolved inorganic phosphate (DIN/DIP) ratio was mostly below 16, with N limitation being dominant. A subsequent analysis using the concentration ratios of N, P, and Si showed that N limitation was dominant during summer and autumn but that Si limitation occasionally occurred during winter and spring in relatively limited areas. However, the dominant limiting nutrient was not determined. The nutrient analysis of the field water collected during the bioassay experiment showed that DIN/DIP revealed P limitation at all stations in March and May, whereas N limitation was dominant in July and October. In the analysis using the concentration ratios of N, P, and Si, P and Si limitation appeared in March and May, but there were points with no dominant limiting nutrient. However, N limitation was dominant in July and October. In the bioassay experiment for assessment of the actual limiting nutrient, the results showed no specific limiting nutrient in March, whereas NH₄⁺ and NO₃^- showed responses in May, July, and October, which confirmed that N was a substantial limiting nutrient directly involved in phytoplankton growth during this period.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.207-216
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• 2021

The purpose of this study was to empirically examine the servicesape focused on Taekwondo gym. More specifically, this study was to investigate the effect of servicescape on gym's image, parents' satisfaction and re-enroll intention. The 250 survey questionnaires were distributed among the trainee's parents of through convenience sampling. Due to the reliability of data, 18 samples were discarded and 232 samples were put to actual analysis. By using SPSS Ver. 21.0, data were analyzed for frequency analysis, exploratory factor analysis, reliability analysis, correlation analysis and multiple regression analysis. The results of the study were as follows. First, the variables of servicescape which was ambient condition, cleanliness and comfort had positive effects on gym's image. Second, the servicescape which was consist of ambient condition, cleanliness, comfort and safety had significantly effects on parents' satisfaction. Third, servicescape which was consist of s ambient condition, cleanliness, comfort and safety had significantly effects on re-enroll intention. This study has a positive meaning in that it confirms the importance of the servicescape of the Taekwondo gym and presents the operation strategy through the servicescape.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1527-1539
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• 2022

As coastal erosion of the east coast is accelerating, the need for scientific and quantitative coastal erosion monitoring technology for a wide area increases. The traditional method for observing changes in the coast was precision monitoring based on field surveys, but it can only be applied to a small area. The airborne bathymetric Light Detection And Ranging (LiDAR) system is a technology that enables economical surveying of coastal and seabed topography in a wide area. In particular, it has the advantage of constructing topographical data for the intertidal zone, which is a major area of interest for coastal erosion monitoring. In this study, time series analysis of coastal seabed topography acquired in Aug, 2021 and Mar. 2022 on the littoral cell GW36 in Gangwon was performed using the Seahawk Airborne Bathymetric LiDAR (ABL) system. We quantitatively monitored the topographical changes by measuring the baseline length, shoreline and Digital Terrain Model (DTM) changes. Through this, the effectiveness of the ABL surveying technique was confirmed in coastal erosion monitoring.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.611-618
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• 2022

The purpose of this study was to confirm the degree of other behaviors among university students in the department of radiology(science) who experienced online classes in the COVID-19 situation and to investigate the effect of self-directed learning ability, flow and academic achievement on other behaviors. The research method was descriptive research. Data were 200 students collected from June 1 to 30 in 2022 using structured questionnaires as students in the Department of Radiology(science). Collected data were analyzed using descriptive statistics, t-test, ANOVA, Cronbach's pearson's correlation, multiple regression analysis with SPSS/WIN 21.0. The result of the study showed that the other behaviors were in the order of 'having s different thought, and 'sending text messages'. other behaviors was 1.75, self-directed learning ability was 3.60, flow was 3.23 and academic achievement was 4.29. There was a significant negative correlation between other behaviors and self-directed learning ability, flow, academic achievement. Factors influencing other behaviors were academic achievement, age, flow, self-directed learning ability in that order. As a result of the above research. it is expected that specific measures and various teaching methods to be flowed in the class are need as the way to lower the other behaviors of university students in the Department of Radiology(science) is to increase academic achievement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.843-852
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• 2022

To determine the composition of benthic species on the southwest coast, a macrobenthos study was conducted at 18 sites on the islands of Wando and Jodo for seven summers (2014-2021) from June to September. Two hundred and twenty species(645 ind./m²) were collected on the rocky shores of Wando and Jodo. A similar number of species was observed in Wando (165 species) and Jodo (167 species). The mean density was higher in Wando (726 ind./m²) than in Jodo (564 ind./m²). The number of species was the highest at Site 15 (116 species), and the density was highest at Site 7 (1,664 ind/m²). The dominant species were Nodilittorina radiata with 175 ind./m² (27.1%), Littorina brevicula with 97 ind./m² (15.1%), and Heminerita japonica with 41 ind./m² (6.3%). The climate change indicator species, Tetraclita japonca, appeared in 15 sites, and the endemic species, Ptilohyale bisaeta, appeared in some sites. Fusinus spectrum, which appears on the Red List as a Near Threatened (NT) species, the lowest level of extinction risk, appeared in Jodo. The macrobenthos of Wando and Jodo demonstrated the general characteristics of rocky shores in Korea. Based on the tides and substrate, the rocky shores revealed a vertical distribution trend where Nodilittorina radiata, Littorina brevicula, Chthamalus challengeri, and Reishia clavigera were dominant. Wando and Jodo exhibited similar habitat distribution patterns.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.211-218
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• 2021

This paper addressed the problems of controlling the coupled pitch-roll motions in a marine vessel exposed to the regular waves in the longitudinal and transversal directions. Stabilization of the pitch and roll motions can be regarded as the essential task to ensure the safety of a ship's navigation. One of the important features in the pitch-roll motions is the resonance phenomena, which result in unexpected large responses in terms of pitch and roll modes in some specific conditions. Besides, owing to its inherent characteristics of coupled combination and nonlinearity of restoring terms, the vessel shows various dynamical behaviors according to the system parameters, especially in the pitch responses. Above all, it can be seen that suppression of pitch rate remains the most significant challenge to overcome for ship maneuvering safety studies. To secure the stable upright condition, a quasi-sliding mode control scheme is employed to reduce the undesirable pitch and roll responses as well as chattering elimination. The Lyapunov theory is adopted to guarantee the closed stability of the pitch-roll system. Numerical simulations demonstrate the effectiveness of the control scheme. Finally, the control goals of state convergences and chattering reduction are effectively realized through the proposed control synthesis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.363-368
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• 2021

Ship engine rooms have improved automation systems owing to the advancement of technology. However, there are many variables at sea, such as wind, waves, vibration, and equipment aging, which cause loosening, cutting, and leakage, which are not measured by automated systems. There are cases in which only one engineer is available for patrolling. This entails many risk factors in the engine room, where rotating equipment is operating at high temperature and high pressure. When the engineer patrols, he uses his five senses, with particular high dependence on vision. We hereby present a preliminary study to implement an engine-room patrol robot that detects and informs the machine room while a robot patrols the engine room. Images of ship engine-room equipment were classified using a convolutional neural network (CNN). After constructing the image dataset of the ship engine room, the network was trained with a pre-trained CNN model. Classification performance of the trained model showed high reproducibility. Images were visualized with a class activation map. Although it cannot be generalized because the amount of data was limited, it is thought that if the data of each ship were learned through transfer learning, a model suitable for the characteristics of each ship could be constructed with little time and cost expenditure.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.394-401
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• 2021

The construction of new renewable energy facilities is steadily increasing every year. In particular, the offshore wind farm market, which has abundant development scalability and a high production coefficient, is growing rapidly. The southwest sea has the highest possible offshore wind power potential, and related projects are to be promoted. This study presents a basic design procedure by the EUROCODE and considers structural safety in the development of an effective of shore wind foundation in the clay layer. In a previous study, the wind power generator of 5MW class was the main target, but the 8MW of wind turbine generator, which meets the technical trend of the wind turbine market in the Southwest sea, was selected as the standard model. Furthermore, a foundation that fulfills the geological conditions of the Southwest sea was developed. The structural safety of this foundation was verified using finite element method. Moreover, structural safety was secured by proper reinforcement from the initial design. Based on the results of this study, structural safety check for various types of foundations is possible in the future. Additionally, specialized structural design and evaluation guidance were also established.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.228-237
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• 2021

In those day, the Busan local government had instituted a rule to support and enhance competition as well as improve respect for the ship management industry. This study aims to extract the cause factors to enhance such competition using intuitionistic decision making trial and evaluation laboratory (DEMATEL) and interpretive structural modeling (ISM) methods. First, eight factors were extracted from the specifications in the Ship Management Industry Development Act. Second, the intuitionistic fuzzy number was converted to a crisp number using the standard fuzzy number. Third, the influence relationship was analyzed using DEMATEL, and the priority ranks for the factors are determined using ISM. From the results of the impact relationship analysis, the three main cause factors were determined as improvement of technical ship management capability, improvement of expertise of manpower for onshore management, and improvement of the quality of the Korean seafarer. The priorities under the ISM method, in descending order, were as follows: improvement of the quality of Korean seafarers, improvement of professionalism among the manpower for shore management, improvement of technical ship management capability, improvement of commercial ship management capability, establishment of a comprehensive information system, improvement of the working conditions and employment environment for seafarers, financial support such as overseas orders, and strengthening the availability of foreign seafarers. Therefore, it is necessary to prioritize policy promotion based on these factors, especially the top three, as these have the highest impact.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.317-324
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• 2021

The purpose of this study was to conduct pan play counseling that contains Korean cultural characteristics to see if it affects college students' anxiety reduction in coronavirus situations. Counseling was conducted for 40 minutes once a week. The associations of participants were recorded for each session. The score of anxiety test decreased in the participants' pre-and post-anxiety tests. The effectiveness of pan play counseling was verified. Case analysis applied phenomenological research method. Structural decisions through case analysis were in the order of regression, expression, differentiation, and integration. In the results of case analysis, participants feel confused through encounters in the early stages and regress unconsciously. Emotions of negativity that could not be erupted in the expression structure appear as consciousness, and the participants awaken. Participants expressed emotions such as fear, anxiety, loneliness, anger, and irritation. Consciousness of the unconscious causes a transformation of ego. The ego gains discernment as the great drama emerges from the differentiated structure. In other words, it builds confidence. The goal of counseling is to reinforce the ego, realizing the potential to overcome anxiety. In the last integration's structure, a wedding, a baby, and a old wise man appeared, showing that a transformation took place. In the results of this study, it was verified that pan play counseling has a healing effect. This study is expected to serve as an opportunity to develop Korean counseling techniques that incorporate Korean culture.