• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.137-143
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• 2003

The prevention of marine accidents has been a important topic in marine society for long time, and various safety policies and countermeasures have been developed and applied to prevent those accidents. In spite of these efforts, however, significant marine accidents have taken place intermittently. Ship is being operated under a highly dynamic environments, and many factors are related with ship's collision, whose factors are interacting. So, the analysis on ship's collision causes are very important to prepare countermeasures which will ensure the safe navigation. This study analysed the ship's collision data over the past 10 years(1991-2000), which is compiled by Korea Marine Accidents Inquiry Agency. The analysis confirmed that‘ship's collision’is occurred most frequently and the cause is closely related with human factor. The main purpose of this study is to analyse human factor. For this, the structure of human factor is analysed by the questionnaire methodology. Marine experts were surveyed based on major elements that were extracted from the human factor affecting to ship's collision. FSM has been widely adopted in modeling a dynamic system which is composed of human factors. Then, the structure analysis on the causes of ship's collision using FSM are performed. This structure model could be used in understanding and verifying the procedure of real ship's collision. Furthermore it could be used as the model to prevent ship's collision and reduce marine accidents.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.115-116
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• 2012

The number of safety accidents of the construction industry is higher than other industries. To prevent the accidents from hazard factor, the employees are variously trained in avoiding an accident. Also many studies have been conducted to reduced the safety accident. But most of these studies are limited to institutional complements. This study proposes safety management improvement plan of safety management through case studies.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.54-63
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• 1996

We establish an expert system for the xylene oxidation reaction process of chemical plants using HAZOP(Hazard and Operability Studies). Our research focus Is only reduced to the cooling system of the total chemical plant due to lack of information. This expert system shows the priority of reasons for the system failure using confidence factor.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.893-903
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• 2008

A method for predicting surface failures which occur during heavy rainfall on mountain slopes is proposed by using the digital land form model that is obtained by reading altitude on a topographical map at 10m grid point space. A depth of a potential failure layer is assumed at each grid point. In the layer, an infiltrated water movement from cell to cell is modeled in the study (cell is a square of the grid). Infiltrated ground water levels which show the three dimensional effects of a topographical factor in an area can be hourly calculated at every cell by the model. The safety factor of every cell is also calculated every hour by the infinite slope stability analysis method with the obtained infiltrated ground water level. Failure potential delineation is defined here as the time when the safety factor becomes less than unity under the assumptions that effective rainfall is 20mm/h and continues 20 hours.

• Structural Monitoring and Maintenance
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• v.7 no.4
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• pp.295-317
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• 2020

Investigation of the stability of arch dam abutments is one of the most important aspects in the analysis of this type of dams. To this end, the Bakhtiari dam, a doubly curved arch dam having six wedges at each of its abutments, is selected. The seismic safety of dam abutments is studied through time history analysis using the design-based earthquake (DBE) and maximum credible earthquake (MCE) hazard levels. Londe limit equilibrium method is used to calculate the stability of wedges in abutments. The thrust forces are obtained using ABAQUS, and stability of wedges is calculated using the code written within MATLAB. Effects of foundation flexibility, grout curtain performance, vertical component of earthquake, nonlinear behavior of materials, and geometrical nonlinearity on the safety factor of the abutments are scrutinized. The results show that the grout curtain performance is the main affecting factor on the stability of the abutments, while nonlinear behavior of the materials is the least affecting factor amongst others. Also, it is resulted that increasing number of the contraction joints can improve the seismic stability of dam. A cap is observed on the number of joints, above which the safety factor does not change incredibly.

• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.29-41
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• 2011

This study investigates the factor that influences commuting time to work when individuals allocate their time for different types of activities. The commuting time is an important indicator for an individual to determine the residence and choose the means of transportation. The analysis uses the data collected from people who live in Seoul metropolitan area including Seoul, Incheon and Gyeonggi Province, and commute to work and making the simple linkage travel (home-work-home) within the area. For the analysis, the Cox hazard proportional methodology was adopted. The method is known to be well applied without assuming any distribution in case of the dependent variable being continuous. For the covariate, the interaction effect between the space variable of the work place and the variable of transportation has been also included in the model. The commuting time to work has been estimated for both 1) the whole metropolitan area and 2) the separate regions i.e., Seoul, Incheon and Gyeonggi-Do. The result reveals that characteristic variables related to individual, household and travel properties influence the mode of transportation and the time allocated for commuting to work (p<0.01). This study also demonstrates the usefulness of the Cox hazard proportional model. The data used in this study is the actual household travel data surveyed in 2006 in the metropolitan area, and analyzing the survey data in 2010 is currently in progress. Comparison of the two survey data sets seeking any behavioral change is suggested for the future study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.457-463
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• 2013

The purpose of this study was to apply the Hazard Analysis Critical Control Point (HACCP) system to the production of dressing. The hazard analysis examined the main materials, industrial water, microbial evaluation, and airborne microorganisms of each working area, as well as the pathogenic microbial contamination risk. The survey was conducted at SJ Company in Jincheon (Chungchengbuk-do), Korea for 30 days from April 1, 2012 to April 30, 2012. The results showed that raw material microorganisms had a total plate count in industrial water below $3.00{\times}10$ CFU/mL in working room I, working room II, the packing room, washing water, and the inspection room for five times in each place. During dressing production (including heat treatment and mixing), general bacteria were detected at an average of $3{\times}10$ CFU/mL, but yeast, mold, and pathogenic bacteria were not detected. Airborne microbiological evaluation (for total plate count, yeast, and mold) found levels below the legal limit at each working area. While workers were positive for microbes in total plate counts, coliform and Staphylococcus aureus were not detected. In conclusion, standards for hygienic management should be established to prevent and decrease hazards, such as general bacteria and pathogenic microorganisms (for example, E. coli, B. cereus, Listeria spp, Salmonella spp, Staph. aureus, Clostridium perfringens, yeast, and mold), and to found critical limits for microorganisms with an HACCP system.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.13-24
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• 2019

The concept of shape similarity has been applied to verify the accuracy of the SIND model, the real-time prediction model for disaster risk. However, the CRITIC method, one of the most widely used in geometric methodology, is definitely limited to apply to complex shape such as hazard map for coastal disaster. Therefore, we suggested the modified CRITIC method of which we added the shape factors such as RCCI and TF to consider complicated shapes. The matching pairs were manually divided into exact-matching pairs and mis-matching pairs to evaluate the applicability of the new method for shape similarity into hazard maps for storm surges. And the shape similarity of each matching pair was calculated by changing the weights of each shape factor and criteria. Newly proposed methodology and the calculated weights were applied to the objects of the existent hazard map and the results from SIND model. About 90% of exact-matching pairs had the shape similarity of 0.5 or higher, and about 70% of mis-matching pairs were it below 0.5. As future works, if we would calibrate narrowly and adjust carefully multi-objects corresponding to one object, it would be expected that the shape similarity of the exact-matching pairs will increase overall while it of the mis-matching pairs will decrease.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.27-31
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• 2018

Classification of explosion hazard areas is very important in terms of cost and safety in the workplace handling flammable materials. This is because the radius of the hazardous area determines whether or not the explosion-proof equipment is installed in the electrical machinery and apparatus. From November 6, 2017, KS C IEC-60079-10-1: 2015 will be issued and applied as a new standard. It is important to understand and apply the difference between the existing standard and the new standard. Leakage coefficients and compression factors were added to the leakage calculation formula, and the formula of evaporation pool leakage, application of leakage ball size, and shape of explosion hazard area were applied. The range of the safety factor K has also been changed. Also, in the radius of the hazardous area, the existing standard applies the number of ventilation to the virtual volume, but the revised standard is calculated by using the leakage characteristic value. In this study, we investigated the differences from existing standards in terms of ventilation and dilution and examined the effect on the radius of the hazard area. Comparisons and analyzes were carried out by applying revised standards to workplaces where existing explosion hazard locations were selected. The results showed that even if the ventilation and dilution were successful, the risk radius was not substantially affected.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.599-606
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• 2015

Damage of landslide due to earthquake covers a considerable part of total damage due to earthquake. Landslide due to earthquake affects direct damage of human lives and structures, and social system can be paralyzed by losing functions of roads, basic industries, and so on. Therefore, systematic and specialized research examining the factors affecting the slope stability by earthquakes should be needed. However, method of evaluation of slope stability problems due to earthquake contains somewhat uncertainty since many soil properties are predicted or assumed. In this study, influences of change of soil properties such as degree of saturation and cohesion value are analyzed in factor of safety and displacement using seismic landslide hazard maps based on GIS. As the degree of saturation increases or cohesion decreases, it is found that seismic landslide hazard area marked with factors of safety or displacements tends to increase. Therefore, to draw more exact landslide hazard map during earthquake, it is necessary to obtain accurate soil property information preferentially from site investigation data in the field.