• Title/Summary/Keyword: Safe Factor

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Structure Analysis of Ship′s Collision Causes using Fuzzy Structural Modeling (퍼지구조모델을 이용한 선박충돌사고 원인의 구조분석)

  • Yang, Won-Jae
    • 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.

A Study on the Failure Cause of Large Scale Rock Slope in Limestone Quarries (석회석 광산에서 발생한 대규모 암반사면의 붕괴원인 분석에 관한 연구)

  • Lee, Sang-Eun;Kim, Hak-Sung;Jang, Yoon-Ho
    • Tunnel and Underground Space
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    • v.24 no.4
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    • pp.255-274
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    • 2014
  • The target of this study is large scale rock slope collapsed by around 7 pm on August, 2012, which is located at ${\bigcirc}{\bigcirc}$ limestone quarries of Gangneung city, Gangwondo. The slope prior to the collapse is formed as the height of about 200 m and the average inclination of $45^{\circ}$. The estimated amount of the collapse is about $1,500,000m^3$ with respect to the slope after the collapse. Geotechnical and field investigations such as boring, geophysical prospecting, surface geological survey, geological lineaments, borehole imaging, metric 3D imaging, experimental and field test, mining work by year, and daily rainfall were performed to find the cause of rock slope failure. Various analyzes using slope mass rating, stereonet projection, limit equilibrium method, continuum and non-continuum model were conducted to check of the stability of the slope. It is expected that the cause of slope failure from the results of various analysis and survey is due to the combined factors such as topography, rainfall, rock type and quality, discontinuities, geo-structural characteristics as the limestone cavity and fault zones, but the failure of slope in case of the analysis without the limestone cavity is not occurred. Safe factor of 0.66 was obtained from continuum analysis of the slope considering the limestone cavity, so the ultimate causes of slope failure is considered to be due to the influence of limestone cavity developed along fault zone.

Measurement of Flash Point for Binary Mixtures of 2-Butanol, 2,2,4-Trimethylpentane, Methylcyclohexane, and Toluene at 101.3 kPa (2-Butanol, 2,2,4-Trimethylpentane, Methylcyclohexane 그리고 Toluene 이성분 혼합계에 대한 101.3 kPa에서의 인화점 측정)

  • Hwang, In Chan;In, Se Jin
    • Clean Technology
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    • v.26 no.3
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    • pp.161-167
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    • 2020
  • For the design of the prevention and mitigation measures in process industries involving flammable substances, reliable safety data are required. An important property used to estimate the risk of fire and explosion for a flammable liquid is the flash point. Flammability is an important factor to consider when developing safe methods for storing and handling solids and liquids. In this study, the flash point data were measured for the binary systems {2-butanol + 2,2,4-trimethylpentane}, {2-butanol + methylcyclohexane} and {2-butanol + toluene} at 101.3 kPa. Experiments were performed according to the standard test method (ASTM D 3278) using a Stanhope-Seta closed cup flash point tester. A minimum flash point behavior was observed in the binary systems as in the many cases for the hydrocarbon and alcohol mixture that were observed. The measured flash points were compared with the predicted values calculated via the following activity coefficient (GE) models: Wilson, Non-Random Two-Liquid (NRTL), and UNIversal QUAsiChemical (UNIQUAC) models. The predicted data were only adequate for the data determined by the closed-cup test method and may not be appropriate for the data obtained from the open-cup test method because of its deviation from the vapor liquid equilibrium. The predicted results of this work can be used to design safe petrochemical processes, such as the identification of safe storage conditions for non-ideal solutions containing flammable components.

A Safety Evaluation of Shoulder Rumble Strips on Expressway using Discriminant Analysis (판별분석을 활용한 노면요철포장의 교통사고감소 효과분석)

  • Park, Je Jin;Seo, Im ki;Kang, Dong Yun;Lee, Jae Hoon
    • Journal of the Korean Society of Safety
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    • v.31 no.1
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    • pp.95-104
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    • 2016
  • In general, the crash reduction effect of the rumble strip is reported to be about 30% in Korea, while it is about 40-60% in the United States. However, the effect is erroneously overestimated because the simple comparison was only made before and after the installation. Accordingly, this study will reassess the crash reduction effect of the rumble strip. The study will also examine the former's geometric characteristics as well as its effect on the causes of the crash. This study analyzed the crash effect while taking into consideration the changes in the horizontal and vertical alignment, including the width of pavement shoulders, using the crash data for two years before and after the installation of the rumble strip. The types of crash caused by the rumble strip were identified using the classification discriminant function. The crash effect on the rumble strip is estimated to be 28.3%, but the pure effect, with the exception of the effect by other elements, was analyzed to be 7.4%. For each expressway design element, the downhill section (2.0-3.0%), the section with less than 3,000 m and more than 10,000 m of the curve radius, and the section with less than 3.0 m of the pavement shoulder width were found to be effective in crash reduction. For each cause of crash, the rumble strip was analyzed to be effective in the reduction of crash caused by "not keeping the safe distance", "sleeping", "negligence in keeping eyes forward", and "excessive handle operation". In particular, the rumble strip was analyzed and seen to be especially effective in preventing crash caused by "not keeping a safe distance," and "sleeping". The installation of the rumble strip was found to be effective in the prevention of crash caused by "not keeping the safe distance" and "sleeping". The results of this study may thus be used in deciding the causes of crash and the installation location of the tailored rumble strip that would be suitable for the geometric characteristics of the roads. This study will also be helpful in the establishment of future traffic safety measures.

Analysis of Key Parameters for Designing the Spent Nuclear Fuel Disposal Container in Korea (사용후핵연료 처분용기 설계를 위한 주요인자 분석)

  • Choi, Jong-Won;Cho, Dong-Keun;Choi, Hui-Ju
    • Journal of Radiation Protection and Research
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    • v.31 no.1
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    • pp.37-46
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    • 2006
  • For the first step to develop a reference disposal container of spent fuel to be used in a deep geological repository, this paper examined safe dimensions of the disposal container on the points of nuclear criticality and radiation safety and mechanical structural safety and provided basic information for dimensioning the container and configuration of the container components, and establishing the favorable and safe disposal conditions. When the safety factor for stress due to the external loads (hydrostatic and swelling pressure) is taken as 2.0, the safe diameter of the filler material to provide enough container strength under the assumed external loads is found to be 112cm with 13cm spacing between inner baskets in PWR container. Also the thickness of the thinner section between the fuel basket and the surface of the cast insert is determined to be 150 mm. Regarding these dimensions of the container, the PWR fuel container is sketched to accommodate 4 square assemblies or 297 CANDU fuel 297 bundles (33 circle tubes x 9 stacks). However the top and bottom parts need to be checked again through the detail radiation shielding analysis with respects to the emplacement position and handling processes of the disposal container.

Speeding Detection and Time by Time Visualization based on Vehicle Trajectory Data

  • Onuean, Athita;Jung, Hanmin
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.10a
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    • pp.593-596
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    • 2018
  • The speed of vehicles has remained a significant factor that influences the severity of accidents and traffic accident rate in many parts of the world including South Korea. This behavior where drivers drive at speeds which exceed a posted safe threshold is known as 'speeding'. Over the past twenty years, the Korean National Police Agency (NPA) has become aware of an increased frequency of drivers who are speeding. Therefore, fixed-type ASE systems [1] have been installed on hazardous road sections of many highways. These system monitor vehicle speeds using a camera. However, the use of ASE systems has changed the behavior of the drivers. Specifically, drivers reduce speed or avoid the route where the cameras are mounted. It is not practical to install cameras at every possible location. Therefore, it is challenging to thoroughly explore the location where speeding occurs. In view of these problems, the author of this paper designed and implemented a prototype visualization system in which point and color are used to show vehicle location and associated over-speed information. All of this information was used to create a comprehensive visualization application to show information about vehicle driving. In this paper, we present an approach detecting vehicles moving at speeds which exceed a threshold and visualizing the points those violations occur on a map. This was done using vehicle trajectory data collected in Daegu city. We propose steps for exploring the data collected from those sensors. The resulting mapping has two layers. The first layer contains the dynamic vehicle trajectory data. The second underlying layer contains the static road networks. This allows comparing the speed of vehicles on roads with the known maximum safe speed of those roads, and presents the results with a visualization tool. We also compared data about people who drive over threshold safe speeds on each road on days and weekends based on vehicle trajectories. Finally, our study suggests improved times and locations where law enforcement should use monitoring with speed cameras, and where they should be stricter with traffic law enforcement. We learned that people will drive over the speed limit at midnight more than 1.9 times as often when compared with rush hour traffic at 8 o'clock in the morning, and 4.5 times as often when compared with traffic at 7 o'clock in the evening. Our study can benefit the government by helping them select better locations for installation of speed cameras. This would ultimately reduce police labor in traffic speed enforcement, and also has the potential to improve traffic safety in Daegu city.

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Safety Assessment of the Level of Safety Culture of National Critical Infrastructure Expressway Operating Organizations (국가핵심기반 고속도로 운영기관의 안전문화 수준진단에 관한 소고)

  • Seo, Jeong-soo;Cheung, Chong-soo
    • Journal of the Society of Disaster Information
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    • v.18 no.3
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    • pp.636-645
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    • 2022
  • Purpose: This study intends to suggest alternatives for improving the level of safety culture by measuring/analyzing safety culture targeting employees of national core-based highway operating organizations. Method: Using the 'Safety Awareness Level Diagnosis Tool' of the Korea Occupational Safety and Health Agency, 16 sub-factor measurement tools reflecting 4 safety culture areas and 4 safety culture activities were evaluated for a total of 144 items. were surveyed/analyzed by online questionnaire. Result: As for the results by safety culture area, "safe operation" was the highest, and "safe communication" was the lowest. As for the results of each safety culture activity, "safe execution (D)", which evaluates whether the plan was implemented, was high. The lowest level of safety culture is "Safety Improvement (A)" Conclusion: When establishing a company's safety and health management measures, the most important aspect of management is the level of safety culture. The ultimate goal is to improve the level of safety culture. In this study, it was possible to confirm the safety culture level of the national core-based expressway operating institution. In the future, we intend to conduct a study on how safety culture affects business continuity management system (BCMS).

A Study on Proposing the Harbor and Fishery Design Criteria for the Channel Width based on External Factors (외력에 따른 항로 폭 설정을 위한 항만 및 어항 설계기준에 관한 연구)

  • Dae-Han Lee;Yu-Min Kwon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.2
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    • pp.184-193
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    • 2024
  • Harbor and Fishery Design Criteria defines that ship routing should be designed to ensure safe ship navigation and easy maneuvering. The design of the channel width is one of the critical conditions in routeing of ships. For the criteria of the channel width, qualitative evaluation criteria are used in South Korea, whereas quantitative evaluation criteria are used in other countries. Environmental factors, such as winds, tidal currents, and waves directly or indirectly affect ship resistance when sailing. Depending on their strength the environmental factors may pose a threat to the safe navigation of ships. Thus, vessel traffic control was regulated in South Korea according to the Beaufort scale. In order to design the channel width to reflect the environmental factors closely related to the safe navigation of ships, quantitative evaluation criteria reflected with environmental factors were presented in other countries, however, these external factors were not considered in South Korea. This study analyzed the relationship between the channel width actually used by ships and environmental factors by using the trajectories of ships entering and leaving Mokpo Port. This study also suggested the required channel width according to tidal currents and compared it with the channel width design criteria of other countries.

A Study on the Risk Control Measures of Ship's Collision (선박충돌사고 위험성 제어방안에 관한 연구)

  • 양원재;금종수;전승환
    • Proceedings of KOSOMES biannual meeting
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    • 2003.05a
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    • pp.59-67
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    • 2003
  • The prevention of marine accidents has been a major 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 and those 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 propose risk control countermeasures of ship's collision. 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.

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A Study on the Risk Control Measures of Ship′s Collision (선박충돌사고 위험성 제어방안에 관한 연구)

  • 양원재;금종수
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.9 no.1
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    • pp.51-56
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    • 2003
  • The prevention of marine accidents has been a major 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 and those factors are interacting. So, the analysis on ship's collision rouses 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 if this study is to propose risk control countermeasures of ship's collision. 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 rouses 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 to reduce marine accidents.

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