• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.247-252
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• 2014

Despite the facts that navigation technology and educational programs were developed, and that maritime law has been enforced strictly, the number of maritime accidents has not dropped significantly. Accident prevention is emphasized because of the extreme life, property, and environmental losses that accompany maritime accidents. Even though there are a variety of preventive activities, their performance is not satisfactory. In order to promote preventive activities and to organize safety management, a Preventive Index of Ship Accident(PISA) and a Preventive Level of Ship Accident(PLSA) which are abstracted from the statistical data of ship accidents (2009~2013) are proposed. The survey module by which these variables can be calculated is composed of preventive domains such as education, engineering, enforcement and information, and is applied for the preventive indexes measurement of cargo, passenger, tanker, tugboat and fishery ships. We compared and analyzed measured result with statistical accident rates and cases to confirm the index utilities. It was found that there is some correlation between the index value and the ship accident rate. It is expected that this index will become useful to evaluate a preventive status for the prevention of ship accidents and for the maritime safety culture.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.168-173
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• 2013

This study was carried out to develop and validate predictive models of E. coli O157:H7 growth. Growth data of E. coli O157:H7 in Paprika were collected at 12, 24, 30 and $36^{\circ}C$. The population increased into 3.0 to 3.8 log10 CFU/g within 4 days, then continued to increase at a slower rate through 10 days of storage at $12^{\circ}C$. The lag time (LT) and maximum specific growth rate (SGR) obtained from each primary model was then modeled as a function of temperature using Davey and square root equations, respectively. For interpolation of performance evaluation, growth data for a mixture of E. coli O157:H7 were collected at time intervals in paprika incubated at the different temperatures, which was not used in model development. Results of model performance for interpolation data demonstrated that induced secondary models showed acceptable goodness of fit. Relative errors in the LT and SGR model for interpolation data (18 and $27^{\circ}C$) was 100%, which show acceptable goodness of fit and validated for interpolation. The primary and secondary models developed in this study can be used to establish tertiary models to quantify the effects of temperature on the growth of E. coli O157:H7 in paprika.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.99-110
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• 2003

In this study, lightening material weight and normalizing structure of preventing system of landslide soil-rock in trench excavation was tried with focusing in safety construction availability and workability. In other words, risk estimate, safety management method investigation, applicability of bracing material and mechanical stability of bracing structure was studied. From these result, structural stability and structural analysis of light weight bracing structure was carried out with common structural analysis program, for examining movement mechanism of bracing structure and normalization of standard. The result are summarized as following. (1) Mechanical ability of bracing members and soil pressure parameter acting to member for ensuring mechanical propriety of bracing structural and useful of new material considering soil mechanics boundary were proposed. Also theory and method of analysis of bracing structural were proposed. (2) As a result of the structure analysis of geographical profile for light pannel used FRP as hard clay mechanical characteristics(bending moment, shear force, axial force) of panel were changed according to groundwater level and it is proved that the result of mechanical analysis is within allowable stress. Thus, light pannel is available for bracing structure in trench excavation.

• Korean Security Journal
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• no.61
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• pp.377-400
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• 2019

Photography is the most commonly used method of documenting the crime and incident scene as it helps maintaining chain of custody (COC) and prove integrity of the physical evidence. It can also capture phenomena as they are. However, digital images can be manipulated and lose their authenticity as admissible evidence. Thus only limited techniques can be used to enhance images, and one of them is Fourier transform. Fourier transform refers to transformation of images into frequency signals. Fast Fourier transform (FFT) is used in this study. In this experiment, we overlapped fingerprints with graph paper or other fingerprints and separated the fingerprints. Then we evaluated and compared quality of the separated fingerprints to the original fingerprints, and examined whether the two fingerprints can be identified as same fingerprints. In the case of the fingerprints on graph paper and general pattern-overlapping fingerprints, fingerprint ridges are enhanced. On the other hand, in case of separating complicated fingerprints such as core-to-core overlapping and delta-to-delta overlapping fingerprints, quality of fingerprints can be deteriorated. Quality of fingerprints is known to possibly bring negative effects on the credibility of examiners. The result of this study may be applicable to other areas using digital imaging enhancement technology.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.574-583
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• 2021

Predicting shipping markets is an important issue. Such predictions form the basis for decisions on investment methods, fleet formation methods, freight rates, etc., which greatly affect the profits and survival of a company. To this end, in this study, we propose a shipping freight rate prediction model for container ships using gated recurrent units (GRUs) and long short-term memory structure. The target of our freight rate prediction is the China Container Freight Index (CCFI), and CCFI data from March 2003 to May 2020 were used for training. The CCFI after June 2020 was first predicted according to each model and then compared and analyzed with the actual CCFI. For the experimental model, a total of six models were designed according to the hyperparameter settings. Additionally, the ARIMA model was included in the experiment for performance comparison with the traditional analysis method. The optimal model was selected based on two evaluation methods. The first evaluation method selects the model with the smallest average value of the root mean square error (RMSE) obtained by repeating each model 10 times. The second method selects the model with the lowest RMSE in all experiments. The experimental results revealed not only the improved accuracy of the deep learning model compared to the traditional time series prediction model, ARIMA, but also the contribution in enhancing the risk management ability of freight fluctuations through deep learning models. On the contrary, in the event of sudden changes in freight owing to the effects of external factors such as the Covid-19 pandemic, the accuracy of the forecasting model reduced. The GRU1 model recorded the lowest RMSE (69.55, 49.35) in both evaluation methods, and it was selected as the optimal model.

• Korean journal of applied entomology
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• v.60 no.3
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• pp.269-276
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• 2021

During 15 months from 13. Jul. 2018 to 29. Oct. 2019, we monitored on the hitchhiker insect pests from a total of 306 foreign vessels entering into Korea. As the results, a total of 805 samples of the hitchhiker insects were collected using simply collecting method by hands and identified as 379 species of 78 families under 12 orders on the basis of integrative species identification. Among them, 42 species (67 individuals) of 21 families under seven orders were detected as not-distributed species in South Korea. Of the 42 not-distributed species, seven species were multiply detected in 2018 and 2019, and two species, Erthesina fullo (Pentatomidae, Hemiptera) and Tessaratoma papilosa (Tessaratomidae, Hemiptera) were discovered as regulated insect pest. Therefore, we reported on the 42 not-distributed species in South Korea with the data sheets for the establishment of a monitoring plan on the not-distributed species and the risk assessments on invasive or invasive likelihood species.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.7-13
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• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.147-161
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• 2021

The purpose of this study was to investigate the psychological state and driving safety of drivers driving around the truck platoon driving. Using the driving simulator, the experimental environment was constructed with the situation of changing lanes to the platoon and driving within the platoon. We tried to qualitatively and quantitatively analyze the driver's psychological state and driving safety through simulation driving experiments. As a result, in the case of the older driver group, there were many cases where they judged themselves to be driving safely, even though they were driving dangerously in the actual lane change to the platoon or driving within the platoon. In particular, this group showed that the narrower the distance between vehicles, the greater the misrecognition. The results of this study are expected to be useful in deriving the optimum interval when the interval between platooning of trucks needs to be temporarily extended.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.1
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• pp.1-8
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• 2023

Purpose: The purpose of this study is to analyze the prognostic factors related to tooth loss after 5 years of periodontal surgery in periodontal disease patients. Materials and Methods: From January to December 2017, 22 patients and 124 teeth who underwent periodontal treatment through periodontal surgery were targeted. At the time of treatment, the measured values were evaluated after recording the maximum probing depth, average periodontal probing depth, number of root, furcation involvement, pulp vitality, and prosthesis state on the day of periodontal surgery. Based on the initial records at the time of visit, patient-related factors were gender, age, smoking, tooth loss due to periodontal disease at the time of first visit, diabetes, and maintenance period. The influence of each factor on tooth loss was evaluated. Results: As a result of examining the influence of tooth-related factors on tooth loss, the maximum probing depth depth (P: 0.000), bone loss (P: 0.021) was found to have a significant effect on tooth loss. Conclusion: As a result of examining the influence of patient-related factors on tooth loss, any variables had no significant effect. Bone loss, maximum probing depth acted as statistically significant prognostic factors for tooth loss in patients who underwent periodontal surgery.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.417-428
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• 2023

The demolition of domestic infrastructures mirrors other significant construction initiatives in presenting a markedly high accident rate. A comprehensive investigation into the origins of such accidents is crucial for the prevention of future incidents. Upon detailed inspection, the causes of demolition construction accidents are multifarious, encompassing unsafe worker behavior, hazardous conditions, psychological and physical states, and site management deficiencies. While statistics relating to demolition construction accidents are consistently collated and reported, there exists an exigent need for a more foundational cause categorization system based on accident type. Drawing from Heinrich's Domino Theory, this study classifies the origins of accidents(unsafe behavior, unsafe conditions) and human errors(human factors) as per the type of accidents experienced during demolition construction. In this study, a three-step model of QFD-FMEA(Quality Function Deployment - Failure Mode Effect Analysis) is employed to systematically categorize accident causes according to the types of accidents that occur during demolition construction. The QFD-FMEA method offers a technique for cause classification at each stage of the demolition process, including direct causes(unsafe behavior, unsafe environment), and human errors(human factors) through a tri-stage process. The results of this accident cause classification can serve as safety knowledge and reference checklists for accident prevention efforts.