• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.139-148
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• 2020

The most important factor affecting the berthing energy generated when a ship berths is the berthing velocity. Thus, an accident may occur if the berthing velocity is extremely high. Several ship features influence the determination of the berthing velocity. However, previous studies have mostly focused on the size of the vessel. Therefore, the aim of this study is to analyze various features that influence berthing velocity and determine their respective importance. The data used in the analysis was based on the berthing velocity of a ship on a jetty in Korea. Using the collected data, machine learning classification algorithms were compared and analyzed, such as decision tree, random forest, logistic regression, and perceptron. As an algorithm evaluation method, indexes according to the confusion matrix were used. Consequently, perceptron demonstrated the best performance, and the feature importance was in the following order: DWT, jetty number, and state. Hence, when berthing a ship, the berthing velocity should be determined in consideration of various features, such as the size of the ship, position of the jetty, and loading condition of the cargo.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.1-19
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• 2008

This research is to analyze the force on landing 3 Type of Halfpipe Curves(Ellipse, Circle, Brachistochrone) based on the mechanical calculation of normal force on a sloping surface. Jumping off a platform on a bard horizontal surface, the flexing of the legs, the softness of the snow, the angle of the landing surface, initial velocity and the forward motion of the snowboarder can contribute to reducing the force on landing. But halfpipe is significantly determined by the curvature of surface. It is definitely verified that the Brachistochrone curve is more safety than others. However currently using the Ellipse curve is mostly safe too. If we consider the efficiency of construction, we can easily think there is no use of another curves except normal ellipse curved halfpipe. It would better that geometrically verity curved halfpipe should be designed for improving fluent skills to snowboarders. This methode of research can be a model of scientifical research on sports safety how can sportsman reduce critical injury by designing optimal halfpipe facilities and manual.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.698-707
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• 2019

The removal of oil spilled by the sinking of a foreign ship in Korea's Exclusive Economic Zone (EEZ) began in May 2019 four years after the ship sunk near Jeju Island. The cleanup was conducted by a foreign company that was contracted to the ship-owner's protection & indemnity (P&I) insurance company. In contrast to the time taken to begin the cleanup, the operation itself was completed in just 22days. Compared to similar cases, the decision to begin the removal was a delayed one. This study analyzes all 93 documents related to the ship's sinking and the eventual cleanup, confirming delays in administrative decision-making on the removal, and identifies factors that influenced this delay. These factors include a neglect of accident-related data verification, and other, legal, technical, environmental, and human aspects. Finally, this study suggests ways to improve decision-making efficiency. As the first study dealing with the cleanup in the EEZ, this research is expected to facilitate decision-making and influence the formulation of policies in the future.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.1-8
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• 2017

Displacement of dams by various instrumentations has been monitored for its safety management and analyzing the behavior after a dam collapse accident. However, unknown displacement of dam has frequently been occurred and it's difficult to analyze behavior of dams more accurately. In this study, improvement of reliabilities for displacement of dams measured by a total station was suggested by calibrating the monitoring system. The position of total station was initially measured through 2-3 given points and the coordinate of the total station was considered as an absolute value. Also, base horizontal and vertical angles had not been considered even if they are important factors when displacement was estimated. In this study, location of the total station and variations of base horizontal and vertical angles were investigated during measuring displacements of targeting points. From the results of this study, they are important factors which are affecting measurements of dam displacements. Before the calibrating, the displacement at 50 m from total station was ${\pm}20mm$. After the calibrating, the displacement was decreased by ${\pm}5mm$.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.4
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• pp.8-18
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• 2020

This study selected landscaping-related precedents among Supreme Court decisions to which the Basic Construction Industry Act and Civil Litigation Act were applied, and divided them by year, by sector type, and by litigation type according to the cause of the litigation, and examined time-series trends and the main characteristics of landscaping-related litigation. As a result of the analysis by year, it became apparent that litigation cases began to appear in earnest in 1977, similar to when landscape licenses were first issued. The types according to the cause of the litigation were analyzed by dividing them into 'planning', 'construction', and 'management'. Among them, 'planning' was the most frequently identified (409 cases). Various precedents were searched according to 'construction', and some of them were found to be due to unclear legal standards related to landscaping. In 'management', cases such as safety accidents and crimes were considered. The users, legal definitions, and purposes of the space served as the basis for judgments. As a result of analysis by case type, there were many administrative landscaping-related cases, and the proportion of criminal cases in the management type was the highest. The results of this study looked at precedents across the entire landscape industry, and it was significant that it provides basic data that could be used by the general public as that they were categorized by field. In the future, amendments to the law and various studies should be conducted to reduce and resolve disputes, and it is necessary to expand the publicity of precedents for this purpose.

• Fire Science and Engineering
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• v.32 no.6
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• pp.1-6
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• 2018

This study is to analyze the characteristics of the yellow insulation ring type of the CSST used for tubing when it is artificially deteriorated and damaged by burning. The CSST for tubing consists of a tube, protective coating, nut, yellow insulation ring, packing, and socket. In addition, it is thought that a yellow insulation ring and rubber packing were used to connect the tube and socket in order to improve the airtightness and insulation performance. The result of the verification of the data acquired from the tests in the 95% confidence interval shows that the Anderson-Darling (AD) and P value were analyzed to be 0.945 and 0.015, respectively. This confirms that the test data of the CSST for tubing is reliable. The analysis of the arithmetic mean of the insulation resistance of a CSST showed that the CSST damaged by burning by a torch, and the one damaged by electrical burning, was $16.7k{\Omega}$ (the greatest relatively) and $208{\Omega}$ (the lowest), respectively, while it was $1.72k{\Omega}$ in the case of a normal product. Therefore, the analysis result of the insulation resistance of the CSST collected from the scene of a fire can be utilized to examine the cause of damage by burning. In addition, it was found that when the maximum current of 97 A was applied to the CSST for about 5 s using a Primary Current Injection Test System (PCITS) the protective film and insulation ring of the CSST has no difference from that of a normal product. However, a part of the metal tube was melted.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.1-12
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• 2015

This study was performed to determine risk ranking of the combination of pathogen-livestock or livestock products to identify the most significant public health risks and to prioritize risk management strategies. First, we reviewed foodborne outbreak data related to livestock products and determined main vehicles and pathogens according to the number of outbreak and case. Second, expert's opinion about management priority of pathogen-livestock product pairing was surveyed with 19 livestock experts in the university, research center, and government agency. Lastly, we used the outcome of Risk Ranger (semi-quantitative risk ranking tool) of 14 combinations of pathogen and livestock or livestock products. We have classified the combination of pathogen-livestock products into group I (high risk), II (medium risk), and III (low risk) according to their risk levels and management priority. Group I, which is the highest risk for foodborne outbreak, includes Salmonella spp./egg and egg products, Campylobacter spp./poultry, pathogenic E. coli/meat and processed ground meat. In conclusion, the results of this study will provide the specific guideline of mid- and long-term planning for risk assessment and risk management prioritization of the combination of pathogen and livestock, or livestock product.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.120-132
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• 2022

Recently, the rapid increase in vacant houses in urban areas has caused various problems such as worsening urban landscape, causing safety accidents, crime accidents, and hygiene problems. According to the Statistics Korea Future Population Estimation results, the growth rate of Korean population and households is expected to continue to decrease, which is likely to lead to an increase in the occurrence of vacant houses. If the problem caused by the occurrence of vacant houses is neglected, it causes not only a physical decline such as a deterioration of the residential environment but also a social and economic decline. In order to solve this problem, it is necessary to grasp the spatial distribution characteristics of vacant houses at the local level considering the existence of regional characteristics and spatial influence. Therefore, in this study, in order to measure global spatial autocorrelation, the analysis was conducted centering on the old downtown area of Busan, where there are many vacant houses through Moran's I and Geographically Weighted Regression(GWR). In addition, the distribution of vacant houses in different spatial units in Eup_Myeon_Dong and Census was analyzed to evaluate the possibility of Modifiable Areal Unit Problem(MAUP), which differ in the results of spatial analysis as the spatial analysis units change. As a result of the analysis, the occurrence of vacant houses by Eup_Myeon_Dong in the old downtown area of Busan had spatial heterogeneity, and the spatial analysis results of vacant houses were different as the spatial analysis units were different. Accordingly, in order to understand the exact distribution characteristics of vacant house occurrence, spatial dimensions using the GWR model should be considered, and it is suggested that consideration of the MAUP is necessary.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.73-88
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• 2000

A series of analysis and experiment on the fishing gear and method of the existing midwater pair trawl net with 12,800mm of maximum mesh size is carried out to determine the most effective shape factor. As the first step of this study, the fishing gear and method for the existing net are analyzed to solve problems, such as being low of the net height by increasing the towing speed, twist of net pendant and twine, suspension of float between knots of mesh. etc. Standing on these results, the existing net are modified by very effective shape based on the theory and technology designing the fishing gear. Also, the model experiment is carried out to determine the most effective shape factor of the modified net in the circulation water channel. The obtained results can be summarized as follows : 1. On the length of net pendants(No.2 and No.3) connected with side line, opening efficiency of net with length 8.0cm of net pendant is the greatest and in the order of 11.5cm, 15.0cm. 2. On the number of the net pendant, opening efficiency of net with 4 lines of net pendant is the greatest and in the order of 3 lines, 2 lines. Center part of side panel is pushed out backward, and the pushed length is increasing by increasing flow speed. 3. On the sinking force, opening efficiency of the net is increasing by increasing sinking force. And opening efficiency shows almost the same when sinking force is greater about 1.5 times than that of the existing net in case of the net with 3 lines of net pendant, and about 1.6 ~ 1.7 times than that of the existing net in case of the net with 2 lines.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.31-40
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• 2014

LNG storage outer tank is a vertically and horizontally prestressed concrete wall structure. Therefore, when the storage tanks become larger, prestressing tendons become longer and eventually the prestressing loss becomes larger. Also, recently, bomb terrors and accidental crashes have occurred frequently on important infrastructures. Therefore, LNG storage tanks are also exposed to these dangerous scenarios, where they need to be evaluated and protected from these threats. Therefore, in this study, the behavior of 270,000 kL LNG storage outer tank impacted by a flying object is evaluated using implicit FEM code, LS-DYNA. In the analysis, the prestress loss due to the increased length of prestressing tendons from enlargement of outer tank is considered. A comparison study between the LNG tanks with and without prestress loss is performed to investigate the impact behavior and the effect of prestressing force change on the safety and serviceability prestressed concrete containment.