• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.8-15
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• 2016

The purpose of this study is to design a model with the structural stability so as not to lose the operational function due to structural plastic or fail of a sliding blast door by blast pressure to this aim, a numerical simulation was performed using full-size experiments and M&S (Modeling & Simulation) of the sliding blast door. The sliding blast door ($W3,000{\times}H2,500mm$) under the blast load is in the form of a sliding type 2-way metal grill, which was applied by a design blast pressure (reflected pressure $P_r$) of 17 bar. According to the experimental results of a real sliding blast door under blast load, the blast pressure reached the sliding blast door approximately 4.3 ms after the explosion and lasted about 4.0 ms thereafter. The maximum blast pressure($P_r$) was 347.7 psi (2,397.3 kPa), it is similar to the UFC 3-340-02 of Parameter(91 %). In addition, operation inspection that was conducted for the sliding blast door after real test showed a problem of losing the door opening function, which was because of the fail of the Reversal Bolt that was installed to prevent the shock due to rebound of the blast door from the blast pressure. According to the reproduction of the experiment through M&S by applying the blast pressure measurement value of the full-size experiments, the sliding blast door showed a similar result to the full-size experiment in that the reversal bolt part failed to lose the function. In addition, as the pressure is concentrated on the failed reversal bolt, the Principal Tensile Failure Stress was exceeded in only 1.25 ms after the explosion, and the reversal bolt completely failed after 5.4 ms. Based on the result of the failed reversal bolt through the full-size experiment and M&S, the shape and size of the bolts were changed to re-design the M&S and re-analyze the sliding blast door. According to the M&S re-analysis result when the reversal bolt was designed in a square of 25 mm ($625mm^2$), the maximum pressure that the reversal bolt receives showed 81% of the principal tensile failure stress of the material, in plastic stage before fail.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.4
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• pp.285-303
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• 2023

Interest in building underground spaces is increasing for the creation of downtown infrastructure and efficient space utilization. A representative method of utilizing underground space is a tunnel, and in addition to road tunnels, the construction of utility tunnels such as power conduits and utility conduits is gradually increasing. The current basic tunnel construction method can be divided into NATM (New Austrian Tunnelling Method) and TBM (Tunnel Boring Machine). The NATM is a reliable method, but it is accompanied by vibration and noise due to blasting. In the case of the TBM excavation method, there are disadvantages in terms of construction period and construction cost, but it is possible to improve economic feasibility by introducing appropriate complementary methods. In this study, a blasting method was develop using the NATM after TBM pre-excavation using the protective shield method. This is a method that compensates for the disadvantages of each tunnel construction method, and is expected to reduce construction costs, blasting vibration, and noise. In order to review the performance of the developed method, an experiment was conducted to evaluate the performance of explosion-proof tube to which a protective shield scale model was applied, and the impact of blasting vibration of the protective shield method was analyzed.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.93-100
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• 2008

Dense of population construction and high density of skyscraper, and geological characteristics caused natural disasters(e.g. typhoon, tsunami, flood, storm, earthquake, etc.) and manmade disasters(e.g. fire, collapse, explosion, traffic accident, etc.). the extent and scale of the disaster are getting larger. To cope with such problems, Busan City has established the basic plan to secure the life and property of the citizens through model strategy and design of Ubiquitous-Safety Busan. This study quantitatively analyzed the ripple effect on local economy through the fulfillment of Ubiquitous-Safety. The production inducing effect of 250 billion won directly and indirectly can be estimated due to the realization of Ubiquitous-Safety. The value added effect of 115 billion won can be estimated. the employment effect of 5,580 persons can be generated with income effect of 51 billion won.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.313-322
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• 2009

Recently, According to computer technology has been improving, Massive customer data has stored in database. Using this massive data, decision maker can extract the useful information to make a valuable plan with data mining. Data mining offers service providers great opportunities to get closer to customer. Data mining doesn't always require the latest technology, but it does require a magic eye that looks beyond the obvious to find and use the hidden knowledge to drive marketing strategies Automotive market face an explosion of data arising from customer but a rate of increasing customer is getting lower. therefore, we need to determine which customer are profitable clients whom you wish to hold. This paper builds model of customer loyalty detection and analyzes customer patterns in automotive market with data mining using association rule and basic statics methods. With 4he help of information technology.

• Fire Science and Engineering
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• v.15 no.3
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• pp.14-20
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• 2001

The flash points are one of the most important fundamental properties used to determine the potential for fire and explosion hazards of flammable substances. A classification of the flash points is important for the safe handling of flammable liquids which constitute the solvent mixtures. Basic to all flash points behavior are vapor pressure and explosive limits(lower explosive limit and upper explosive limit). The flash points of flammable solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and activity coefficient models. In this study, the reference values of lower flash points were compared with the calculated values by using Raoult's law and MRSM(modified response surface methodology) model. The lower flash points were in agreement with the predicted by Raoult's law and MRSM model. By means of this methodology, it is possible to evaluate reliability of experimental data of the flash points of the flammable mixtures.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.27-33
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• 2010

Analysis of gas accidents for 11.5 years, from 1998 to June, 2009, by types has been made in this study to prevent the recurrence of accidents through the analysis of gas accident occurring environment. Gas using environment and gas accidents are forced to be closely connected since the number of gas accidents has not only been decreased but occurred steadily and gas using types are changing by time period, weather, etc. in terms of accident contents. Gas accidents have been occurred more in capital areas with larger gas usage and specific local governments. The possibility of the gas accidents hit the highest when the weather is clear, the wind speed is low and the humidity is in the middle. In addition, leakage of gas, fire or explosion are also considered to be closely related with the weather as a result of model observance of gas accidents types. All the gas related possible accidents are also considered to be predictable if this result is to be analysed in association with the weather.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.56-63
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• 2017

Hydrogen charging station was invested and supported around the world. In this study, the extent of damage caused by VCE in the charging station handling liquefied hydrogen was calculated, and the human and material damage was estimated through the Probit model. In addition The optimal height of vent stack for low temperature hydrogen was set. The damage range is 8.24m in small scale, 14.10m in medium scale, and 22.38m in large scale based on interest overpressure 6.9kPa. In case of death due to pulmonary hemorrhage, 50m of the small and medium scale and 100m of the large scale were injured. Structural damage was 200m in small scale, 300m in medium scale and 500m in large scale. The optimum height of the vent stack is 4.7 m in small scale, 8.8 m in medium scale and 16.9 m in large scale.

• Explosives and Blasting
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• v.34 no.4
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• pp.10-18
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• 2016

Explosive blasting utilizes the energy produced from the explosion of explosive materials. Since the black powder, the first type of explosive, was invented, various types of explosives have been developed until a recent emulsion explosive which is powerful as well as safe in use. The detonators continue to be developed from safety fuse to the recent electronic detonators which allow extremely accurate and flexible control of delay time. However, the good explosives and detonators do not always lead to the good blast results. It entirely depends on the blast engineer. It is necessary to develop the empirical or theoretical models based on the field experience and sound theoretical algorithm. Such models would be very useful for blast design and, furthermore, provide the idea of further technical development. This paper introduces some models used in explosive blasting and attention to be paid for field application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5276-5298
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• 2019

Internet of Things (IoT) based sensor networks have gained unprecedented popularity in recent years. With the exponential explosion of the objects (sensors and mobiles), the bandwidth and the speed of data transmission are dwarfed by the anticipated emergence of IoT. In this paper, we propose a novel heterogeneous IoT model integrated the power line communication (PLC) and WiFi network to increase the network capacity and cope with the rapid growth of the objects. We firstly propose the mean transmission delay calculation algorithm based the 3D Markov chain according to the multi-priority of the objects. Then, the attractor selection algorithm, which is based on the adaptive behavior of the biological system, is exploited. The combined the 3D Markov chain and the attractor selection model, named MASM, can select the optimal path adaptively in the heterogeneous IoT according to the environment. Furthermore, we verify that the MASM improves the transmission efficiency and reduce the transmission delay effectively. The simulation results show that the MASM is stable to changes in the environment and more applicable for the heterogeneous IoT, compared with the other algorithms.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.857-864
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• 2012

Reviewing the statistics of harbor shipment of hazardous and noxious substance and the past spill accidents of HNS enabled us to assess the potential risks of transportation of HNS through the major harbors in Korea. Ulsan, Yeosu, Daesan port are relatively evaluated high risk in fire, health and environment disaster. Through the analysis of domestic preparedness to HNS accidents, the supplement of expertise resource to respond the vulnerability of the explosion, the fire and the physiological hazard, is required. Based on this risk assessment and review of the advanced case of Japan in building up HNS response system, a resource model at a national level was proposed which differentiates the sea areas for the proper allocation of resources to respond effectively to HNS accidents in the future.