• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.2
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• pp.67-76
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• 2020

This study aims to optimize the cochlea-inspired artificial filter bank (CAFB) using El-Centro seismic waveforms and test its performance through a shaking table test on a two-span bridge model. In the process of optimizing the CAFB, El-Centro seismic waveforms were used for the purpose of evaluating how they would affect the optimizing process. Next, the optimized CAFB was embedded in the developed wireless-based intelligent data acquisition (IDAQ) system to enable response measurement in real-time. For its performance evaluation to obtain a seismic response in real-time using the optimized CAFB, a two-span bridge (model structures) was installed in a large shaking table, and a seismic response experiment was carried out on it with El-Centro seismic waveforms. The CAFB optimized in this experiment was able to obtain the seismic response in real-time by compressing it using the embedded wireless-based IDAQ system while the obtained compressed signals were compared with the original signal (un-compressed signal). The results of the experiment showed that the compressed signals were superior to the raw signal in response performance, as well as in data compression effect. They also proved that the CAFB was able to compress response signals effectively in real-time even under seismic conditions. Therefore, this paper established that the CAFB optimized by being embedded in the wireless-based IDAQ system was an economical and efficient data compression sensing technology for measuring and monitoring the seismic response in real-time from structures based on the wireless sensor networks (WSNs).

• International conference on construction engineering and project management
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• 2022.06a
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• pp.923-928
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• 2022

Wildfire disasters in the United States impact lives and livelihoods by destroying private homes, businesses, community facilities, and infrastructure. Disaster victims suffer from damaged houses, inadequate shelters, inoperable civil infrastructure, and homelessness coupled with long-term recovery and reconstruction processes. Cities and their neighboring communities require an enormous commitment for a full recovery for as long as disaster recovery processes last. State, county, and municipal governments inherently have the responsibility to establish and provide governance and public services for the benefit and well being of community members. Municipal governments' comprehensive and emergency response plans are the artifacts of planning efforts that guide accomplishing those duties. Typically these plans include preparation and response to natural disasters, including wildfires. The standard wildfire planning includes and outlines (1) a wildfire hazard assessment, (2) response approaches to prevent human injury and minimize damage to physical property, and (3) near- and long-term recovery and reconstruction efforts. There is often a high level of detail in the assessment section, but the level of detail and specificity significantly lessons to general approaches in the long-term recovery subsection. This paper aims to document the extent of wildfire preparedness at the county level in general, focusing on the long-term recovery subsections of municipal plans. Based on the identified challenges, the researchers provide recommendations for better longer-term recovery and reconstruction opportunities: 1) building permit requirements, 2) exploration of the use of modular construction, 3) address through relief from legislative requirements, and 4) early, simple, funding, and the aid application process.

• Geomechanics and Engineering
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• v.36 no.5
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• pp.427-440
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• 2024

This study concentrates on the 301 comprehensive caving working face, notable for its considerable mining height. The roof model is established by integrating prior geological data and the latest borehole rock stratum's physical and mechanical parameters. This comprehensive approach enables the determination of lithology, thickness, and mechanical properties of the roof within 50 m of the primary mining coal seam. Utilizing the transfer rock beam theory and incorporating mining pressure monitoring data, the study delves into the geometric parameters of the direct roof, basic roof movement, and roof pressure during the initial mining process of the 301 comprehensive caving working face. The direct roof of the mining working face is stratified into upper and lower sections. The lower direct roof consists of 6.0 m thick coarse sandstone, while the upper direct roof comprises 9.2 m coarse sandstone, 2.6 m sandy mudstone, and 2.8 m medium sandstone. The basic roof stratum, totaling 22.1 m in thickness, includes layers such as silty sand, medium sandstone, sandy mudstone, and coal. The first pressure step of the basic roof is 61.6 m, with theoretical research indicating a maximum roof pressure of 1.62 MPa during periodic pressure. Extensive simulations and analyses of roof subsidence and advanced abutment pressure under varying working face lengths. Optimal roof control effect is observed when the mining face length falls within the range of 140 m-155 m. This study holds significance as it optimizes the working face length in thick coal seams, enhancing safety and efficiency in coal mining operations.

• Journal of Korean Society of Disaster and Security
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• v.6 no.3
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• pp.1-8
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• 2013

Based on random vibration theory, a procedure for calculating the dynamic response of the tall building to time-dependent random excitation is developed. In this paper, the fluctuating along- wind load is assumed as time-dependent random process described by the time-independent random process with deterministic function during a short duration of time. By deterministic function A(t)=1-exp($-{\beta}t$), the absolute value square of oscillatory function is represented from author's studies. The time-dependent random response spectral density is represented by using the absolute value square of oscillatory function and equivalent wind load spectrum of Solari. Especially, dynamic mean square response of the tall building subjected to fluctuating wind loads was derived as analysis function by the Cauchy's Integral Formula and Residue Theorem. As analysis examples, there were compared the numerical integral analytic results with the analysis fun. results by dynamic properties of the tall uilding.

• Korean Journal of Construction Engineering and Management
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• v.19 no.3
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• pp.11-22
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• 2018

Existing efforts to reduce total egress time actually focused on reducing travel time. However, consideration to reduce perception time or response time was insufficient although the ratio of travel time is one-third of total egress time and situations which the safety cannot be ensured by only reducing travel time were aroused. Therefore, the concept of disaster information, which could reduce both perception time and response time got attention To analyze the effect of disaster information on occupant behaviour, this study identified a relationship between 10 major disaster information and 3 occupant behaviour factors in terms of reducing egress time. By referring the relationship, this study conducted an virtual egress experiment with survey on 4 cases, the elderly, intellectual disabled, hearing disabled and visual disabled, to identify disaster information which reduce total egress time effectively. Finally, by analyzing the experiment result, this study proposed the process of disaster information effect on occupant behaviour as complementing insufficient occupant behaviour to ensure the minimum level of safety and maximizing relatively high occupant behaviour to ensure enough level of safety. The results are expected to account for relationship between disaster information and occupant behaviour with more explanatory power in terms of egress time. With further studies of disaster information and group behaviour, these series of studies could provide basic references for disaster information and occupant behaviour.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.821-840
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• 2016

A simple design process is proposed for supplemental viscous dampers based on structural safety redundancy. In this process, the safety redundancy of the primary structure without a damper is assessed by the capacity and response spectra. The required damping ratio that should be provided by the supplemental dampers is estimated by taking the structural safety redundancy as a design target. The arrangement of dampers is determined according to the drift distribution obtained by performing pushover analysis. A benchmark model is used to illustrate and verify the validity of this design process. The results show that the structural safety redundancy of the structure provided by the viscous dampers increases to approximately twice that of the structure without a damper and is close to the design target. Compared with the existing design methods, the proposed process can estimate the elastic-plastic response of a structure more easily by using static calculation, and determine the required damping ratio more directly without iterative calculation or graphical process. It can be concluded that the proposed process is simple and effective.

• Geomechanics and Engineering
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• v.32 no.4
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• pp.375-385
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• 2023

There are many joint fissures distributed in the engineering rock mass. In the process of geological history, the underground rock mass undergoes strong geological processes, and undergoes complex geological processes such as fracture breeding, expansion, recementation, and re-expansion. In this paper, the damage-stick-slip process (DSSP), an analysis model used for rock mass failure slip, was established to examine the master control and time-dependent mechanical properties of the new and primary fractures of a multi-fractured rock mass under the action of stress loading. The experimental system for the recemented multi-fractured rock mass was developed to validate the above theory. First, a rock mass failure test was conducted. Then, the failure stress state was kept constant, and the fractured rock mass was grouted and cemented. A secondary loading was applied until the grouted mass reached the intended strength to investigate the bearing capacity of the recemented multi-fractured rock mass, and an acoustic emission (AE) system was used to monitor AE events and the update of damage energy. The results show that the initial fracture angle and direction had a significant effect on the re-failure process of the cement rock mass; Compared with the monitoring results of the acoustic emission (AE) measurements, the master control surface, key blocks and other control factors in the multi-fractured rock mass were obtained; The triangular shaped block in rock mass plays an important role in the stress and displacement change of multi-fracture rock mass and the long fissure and the fractures with close fracture tip are easier to activate, and the position where the longer fractures intersect with the smaller fractures is easier to generate new fractures. The results are of great significance to a multi-block structure, which affects the safety of underground coal mining.

• Journal of Information Technology Services
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• v.12 no.3
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• pp.151-163
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• 2013

It is no doubt that information technology is the key factor of national safety. Information technology is positively useful for national security such as crime prevention and detection, criminal investigation, disaster management, and national defense. However, it might be a threat to the security as we saw in the examples such as '3.4 DDoS attacks' and 'Nong-hyup Computer Network Failure.' Although the effect that information technology makes upon the national security is immense, the current legal system does not reflect these changes well. National security should be kept during 'prevention-response-recovery' process regardless it is in the online on offline. In addition, public administration for national security should be based on laws. However, the current legal system is lack of legislative basis on cyber and physical disaster, and the laws on the response to disaster might cause confusing. Therefore, this study examines the limitation of the current legal system on national security, and suggests directions for the development of the system based on the new establishment of the legal concept for 'national security'.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.121-132
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• 2014

In recent years, the surroundings of Fire have rapidly changed and citizens need for Fire have been demanding very high. Under these situations, in order for satisfaction to all these demands, Seoul Metropolitan Government Fire Academy(SFA) have only to improve its educational training program as the fire educational training center in Korea. The purpose of this study is to scrutinize current educational training program of SFA and measure the relative weight among the hierarchy of disaster management(prevention and mitigation-preparedness-response-recovery) by using the Analytic Hierarchy Process(AHP). The result of this study presents that how many hours must be allocated and set the educational training program with scientific and systematic way of AHP compared the current program of SFA in 2013. And This study is applied to increase access and comprehension about the AHP and will be able to present guideline for the selection of optimal the educational training of SFA to serve Seoul citizens the best Fire services.

• Journal of Korean Society of Disaster and Security
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• v.6 no.1
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• pp.87-91
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• 2013

Establish standards and review procedures for on-site implementation of the emergency response plan required to establish by substances requiring preparation for accidents. Investigated for the examination content and standards for Process Safety Management (PSM) and Safety Management System (SMS). Safety Management System operator's comments and problems to be expected in the review process. Standards for on-site implementation and review of a person's ability to do the job does not require a high level of expertise. However, it has been created mainly to determine whether appropriate items to be included in the report and the contents presented.