• Geomechanics and Engineering
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• v.27 no.6
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• pp.537-550
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• 2021

There are various technical problems need to be solved in the construction process of pre-setting an isolation wall into a double lane in the outburst prone mine. This study presents a methodology that pre-setting an isolation wall into a double lane without a coal pillar. This requires the excavation of two small section roadways to dig a wide section roadway, followed by construction of the separation wall. During this process the connecting lane is reserved. In order to ensure the stability of the separation wall, the required bearing capacity of the isolation wall is 4.66 MN/m and the deformation of the isolation wall is approximately 25 cm. To reduce the difficulty of implementing support the roadway is driven by 5 m/d. After the construction of the separation wall, the left side coal wall is brushed 1.5 m to make the width of the gas roadway reach 2.5 m and the roadway support utilizes anchor rod, ladder beam, anchor cable beam and net configuration. During construction, the concrete pump and removable self-propelled hydraulic wall mold are used to pump and pour the concrete of the isolation wall. In the process of mining, the stress distribution of coal body and isolation wall is detected and measured on site. The results demonstrate that the deformation of the surrounding rock of roadway and separation of roof in the roadway is small. The stress of the bolt and anchor cable is within equipment tolerance validating their selection. The roadway is well supported and the intended goal is achieved. The methodology can be used for reference for similar mine gas control.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.281-286
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• 2006

In case of Korea, immovable property like location, land prise or investment value is more highly estimated than quality of life of residents for performance and value of apartment house, because of limited land area or high density of population. But the high level of life has recently caused the increasing demand in better life. As there is no cases to provide the house in bulk due to the housing market condition, it is necessary to evaluate performance and value of structure, disaster prevention safety, habitability, antiquated condition of building and equipment, maintenance condition and so on that has importantly influence on resident's life quality. So, this study aims to understand the actual condition of environmental performance for the present apartment by comparing the designated apartment, which is ready to have completed in Daegu, with the mixed use residential building, which gained the best grade for green building certification system. Also by analyzing and evaluating a right to enjoy sunshine, floor impact noise etc. and indoor air quality.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.225-233
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• 2010

We performed 3 dimensional numerical study on the improvement of the airflow deflection in the cleanroom of Class 1000, which is presently operated for the manufacturing process in Korea. The Deflection angle and the non-uniformity were investigated to analyze the airflow characteristics and the performance of cleanroom with variations of the cleanroom occupancy state, the filters' arrangement, and the floor return air system. From the numerical results, we found out that the airflow pattern of the cleanroom is more unidirectional and stable in the condition of at-rest than in the condition of as~built. It is due to that the equipments installed in the cleanroom play a role like partitions, which prevent the airflow from inclining toward the recirculation air duct. And it is needed to arrange the filter units parallel to the equipments array without a gap between them for maintaining the unidirectional airflow pattern. Finally, we knew that it is very important to install the partition like the eyelid above the equipment to keep the unidirectional airflow around the equipments and remove the contaminants quickly.

• Journal of Korean Society for Quality Management
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• v.44 no.2
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• pp.451-466
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• 2016

Purpose: This study was to identify customers' demands in railway services system and then to seek the way to satisfy the customer expectations. Methods: We suggest a Quality Function Deployment(QFD)-based approach comprised of three stages. In first stage, SERVPERF survey was carried out to assess current positions of customer expectations in the market. Then, factor analysis was incorporated into SERVPERF to classify customer expectations for the house of quality. In the second stage, the analytic network process was used to prioritize the importance of the customer attributes. Finally, QFD was performed utilizing customer attributes and their weights. Results: The QFD identified the most important customer expectations as: accident prevention, swift reaction to accident, on-time arrivals and departures of the train. It also shows that driving capability, equipment for safety, and training for disaster are the most critical technical requirements. Conclusion: The results are useful for identifying the customers' demands in railway services systems, and they can contribute to the service quality and customer satisfaction.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.95-103
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• 2019

Safety and welfare of forestry is very poor because of poor working environment, decreasing workforce and budget, and aging. These have brought many accidents and casualties. The accident rate in the field of forestry were about 2.83 times higher than average of an entire industry and mortality rate were 1.84 times higher than it. The most reason among the mortality accident was caught in, under or between objects and struck by objects. In analysis of 60 serious accident cases, the number of occurrence s of caught in, under or between objects and struck by objects were the highest. We suggest education, engineering, environment, and enforcement methods which is first aid education and emergency response system, equipment of combined IoT technologies and sensors, and certification and career program on the basis of the results.

• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.73-79
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• 2022

In this study, real fire tests were performed on representative combustibles of residential facilities to analyze the fire behavior and combustion characteristics in a small residential space. The considered combustibles were a sofa, a combination of a desk and a chair, and a combination of a mattress and an electric mat. A compartment space fire test was performed using the room corner test equipment prescribed in the KS F ISO 9705 specification. Three real fire tests were conducted by placing the combustible material inside a small compartment with insulation and finishing materials and by igniting the combustible material. Results showed that the peak heat release rate and peak smoke production rate occurred in the combination of the mattress and electric mat. Furthermore, from the result of the fire rate analysis, it was estimated that the fire risk of the mattress and electric mat combination was the highest, followed by the sofa and thedesk and chair combination.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.117-129
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• 2023

This study tested the effect on the toxicity of formaldehyde to select a shelter site due to formaldehyde leakage. As a result of the experiment, the range of ERPG-2 and 3 is between 2.2km and 9.6km, ASET is 6 minutes at 1km, 15 minutes at 3km, 22 minutes at 5km, and the lethality rate is 99.9% at 1km and 9% at 3km. In areas where refuge time is less than 15 minutes or the lethality rate is more than 2%, a shelter is installed. This is because if there are only a few evacuees, the evacuation time may take longer than the pre-movement time of 15 minutes or less specified in PD 7974-6:2004, and the lethality rate with the lowest number of deaths was calculated to be 2%. The shelter must be equipped with a hepa-filter, positive pressure equipment, air purifier, air respirator, goggles, chemical protective clothing type 4 and sufficient parking space must be secured to ensure the safety of evacuees.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.255-266
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• 2024

The purpose is to evaluate evacuation safety by simulating the toxic effects of hydrogen fluoride leaks in areas surrounding national industrial complexes and to suggest alternatives for areas that do not satisfy evacuation safety. For human casualties caused by hydrogen fluoride leakage accidents, Available Safe Egress Time (ASET) is calculated by the toxic effects quantified with the Areal Locations of Hazardous Atmospheres (ALOHA), an off-site consequence assessment program. The Required Safe Egress Time (RSET) is calculated through Pathfinder, an evacuation simulation program. Evacuation safety is assessed by comparing ASET and RSET. The ALOHA program was used to evaluate the time to reach AEGL-2 concentration in 12 scenarios. The Pathfinder program was used to assess the total evacuation time of the high school among specific fire-fighting objects. Of the 12 accident scenarios, ASET was larger than RSET in the worst-case scenarios 1 and 9. For the remaining 10 accident scenarios, the ASET is smaller than the RSET, so we found that evacuation safety is not guaranteed, and countermeasures are required. Since evacuation safety is not satisfactory, we proposed to set up an evacuation area equipped with positive pressure equipment and air respirators inside specific fire-fighting objects such as the high school.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.401-412
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• 2020

This study analyzed the causes of warehouse fires using a creative problem-solving technique called TRIZ. It identified preventive measures by applying 4M. The results are as follows. First, this study examined the inconsistency among the causes of warehouse fires using TRIZ. Second, it analyzed human factors and fire prevention measures in warehouses such as safety standards for managers, and methods for the promotion of safety consciousness among workers, and for the reinforcement of construction technology for sandwich panel workers. Third, it identified the mechanical and facility factors and fire prevention measures in warehouses such as safety facilities, the expanded installation of safety devices, the adoption and development of fire suppression equipment, and the deployment of methods to improve the fire resistance of sandwich panels. Fourth, it presented working and environmental factors and fire prevention measures in warehouses such as the tightening of safety precautions and the supervision of working methods, and setting fire partitions both in loading places and based on performance-based design. Finally, it proposed managerial factors and fire prevention measures in warehouses such as specific targeting for firefighting with low fire hazards, reviewing the material quality regulations of non-combustible or higher for sandwich panels in the specific target of firefighting that cannot apply fire safety standards, installing sprinklers in cold storage, and mandating the installation of automated facilities with retroactive application regardless of the floor area in the warehouse with a sandwich panel structure.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.10-21
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• 2021

Recently, the demand for atypical structures with functions and sculptural beauty is increasing in the construction industry. Existing mold-based structure production methods have many advantages, but building complex atypical structures represents limitations due to the cost and technical characteristics. Production methods using molding are suitable for mass production systems, but production cost, construction period, construction cost, and environmental pollution can occur in small quantity batch production. The recent trend in the construction industry calls for new construction methods of customized small quantity batch production methods that can produce various types of sophisticated structures. In addition to the economic effects of developing related technologies of 3D Concrete Printers (3DCP), it can enhance national image through the image of future technology, the international status of the construction civil engineering industry, self-reliance, and technology export. Until now, 3DCP technology has been carried out in producing and utilizing residential houses, structures, etc., on land or manufacturing on land and installing them underwater. The final purpose of this research project is to produce marine structures by directly printing various marine structures underwater with 3DCP equipment. Compared to current underwater structure construction techniques, constructing structures directly underwater using 3DCP equipment has the following advantages: 1) cost reduction effects: 2) reduction of construct time, 3) ease of manufacturing amorphous underwater structures, 4) disaster prevention effects. The core element technology of the 3DCP equipment is to extrude the transferred composite materials at a constant quantitative speed and control the printing flow of the materials smoothly while printing the output. In this study, the extruding module of the 3DCP equipment operates underwater while developing an extruding module that can control the printing flow of the material while extruding it at a constant quantitative speed and minimizing the external force that can occur during underwater printing. The research on the development of 3DCP equipment for printing concrete structures underwater and the preliminary experiment of printing concrete structures using high viscosity low-flow concrete composite materials is explained.