• 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.

• Explosives and Blasting
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• v.25 no.2
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• pp.35-46
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• 2007

The excavation of ground by blasting is widely accepted during construction of the various infrastructures because the cost is relatively low and its process is simple. Although the ground vibration accompanied by the blasting has drawn many theoretical and experimental research interests, the environmental influence of the air blast tends to be overlooked. This means the noise produced from construction sites have been neglected academically even though it is very controversial and hypersensitive case causing many conflicts in environmental problems. In the light of this, this study explores a way of calculation of air blast. Specifically, we measure the actual air blast and explosive noise, and then make the predicted formula of them based on the change of charge per delay using regression analysis. The comparison with the predicted and measured results helps to determine the validity of estimated formula.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.545-554
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• 2019

The customary approach used in the blast vibration analysis is to derive empirical relations between the peak particle velocities of blast-induced waves and the scaled distance, and to develop patterns limiting the amounts of explosives. During the periods when excavations involving blasting were performed at sites far from residential areas and infrastructure works, this method based on empirical correlations could be effective in reducing vibrations. However, blasting procedures applied by the fast-moving mining and construction industries today can be very close to, in particular cities, residential areas, pipelines, geothermal sites, etc., and this reveals the need to minimize blast vibrations not only by limiting the use of explosives, but also employing new scientific and technological methods. The conventional methodology in minimizing blast vibrations involves the steps of i) measuring by seismograph peak particle velocity induced by blasting, ii) defining ground transmission constants between the blasting area and the target station, iii) finding out the empirical relation involving the propagation of seismic waves, and iv) employing this relation to identify highest amount of explosive that may safely be fired at a time for blasting. This paper addresses practical difficulties during the implementation of this conventional method, particularly the defects and errors in data evaluation and analysis; illustrates the disadvantages of the method; emphasizes essential considerations in case the method is implemented; and finally discusses methods that would fit better to the conditions and demands of the present time compared to the conventional method that intrinsically hosts the abovementioned disadvantages.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.335-342
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• 2014

In this paper, reference erosion criteria value suitable for progressive collapse analysis of RC structure due to blast load is proposed. Erosion is fundamentally a numerical technique to overcome the problems such as large numerical errors or abrupt termination of analysis and previous study has been suggested value for blast analysis. But concrete has different stress-strain curve according to strain rate. Consequently, the erosion criteria for the realistic progressive collapse simulation were suggested by comparing experiment results and numerical analysis results. Finally, the real progressive collapse of Oklahoma Federal Building was analyzed by using the median value of two values. And as a result, the analysis result is the actual collapse of the well described.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.267-275
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• 2002

We have developed GComp as an analysis tool for microbial genome comparison. This tool exploits BLAST or FASTA as a preprocessing program for local alignments to detect homologous regions, parses the homology search results, and generates tables and files to show homology relationship between two genomes at a glance. The interface for graphical representation of the comparative genomic analysis has been also implemented. Our test cases shows that the program can be useful in practice for intuitive and quantitative comparison of microbial genome sequence pairs as well as self-genome analysis. A few additional features have been devised and designed, which will be added in the further development.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.1
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• pp.27-35
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• 2002

For the excavation of the rock, blast method is put into operation in most of the construction site in Korea. In comparison to other methods of excavation, blast method has many merits such as improvement in efficiency in operation, reducement of operation period, and etc. However, blast operation also creates much loss due to the blast vibration, noise, and fly rocks. Thus, in this study, we have examined main features, rock fragmentation effect and the application of plasma method the one of shallow vibration method. In this study, the attenuation exponent of blast method operated in the site was 1.39~1.40 and that of the plasma method was analysed to be 1.45~2.23. From the location where the distance between excavation location and observation location was over 15 m, most of excavation vibration were measured to be less than 0.2 kine(cm/sec), which is also the allowed standard value of sensitive buildings, such as cultural assets and computer facilities. According to the result of FFT(Fast Fourier Transform) analysis, the frequency measured through blast method in this site was 30~50 Hz and the frequency of plasma method ranges in between 30~130 Hz.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.34-41
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• 2008

In this paper, we present an asymptotical analysis of channel capacity of Bell labs layered space-time (BLAST) architectures based on a zero-forcing (ZF) criterion in the sense of signal-to-noise ratio (SNR). We begin by introducing a new relationship related to multi-input multi-output (MIMO) channel capacity. We prove that Diagonal Bell Labs Space-Time (DBLAST) attains the lower bound for MIMO channels when interference nulling is carried out based on the ZF-criterion. An exact closed-form expression for the probability density function of the channel capacity is analyzed. Based on the asymptotic behavior of the channel capacity of each layer, closed-form expressions for the asymptotic ergodic capacity are derived for BLAST. Based on the analysis presented in this paper, we gain an insight on the channel capacity behavior for a MIMO channel. Computer simulation results have verified the validity and accuracy of the proposed analysis for a wide range of antenna array sizes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.875-878
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• 2006

In the case of a vibration sensitive equipment, it require a vibration free environment to provide its proper function, therefore, it is very important to predict precisely vibration environment of microelectronics production facility due to adjacent blast work. However, it is not easy to evaluate a quantitative vibration response of structure due blast because it can be determined by the characteristics of vibration sources, propagation through rock and soil and dynamic properties of building. In this paper, vibration influence evaluation of micro-electronic Production building induced from adjacent blast activity was performed by real measurement data obtained on ground and structure at same time. And blast vibration allowable limit on ground was supposed by measurement data analysis in order to avoid operation error of precision equipments

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.164-165
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• 2019

Light-weight foamed concrete using cement as a raw material consumes a lot of energy and generates $CO_2$ because of the high temperature firing process in the manufacturing process of cement. This study was carried out to evaluate the use of blast furnace slag through the properties analysis by substituting a certain amount of blast furnace slag as an industrial by-product as a substitute for cement. The experimental results showed similar characteristics to those of using only cement when the blast furnace slag fine powder was used in an appropriate amount. Therefore, if a certain amount of cement is replaced with blast furnace slag powder, it can maintain similar quality, reduce natural resources and energy consumption, and reduce carbon dioxide emissions.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.402-405
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• 2005

We have previously identified genes for four different protease inhibitors (PIs) that were induced upon rice blast infection in a rice blast resistant mutant SHM-11. Our expression analysis of the PIs indicated that induction of the PIs was the highest 24 hr after rice blast inoculation in the rice mutant SHM-11. Three PIs in the group of serine PIs were highly expressed while a cystein PI was weakly expressed upon rice blast inoculation. Four PIs were weakly induced 48 hr after pathogen inoculation in rice blast susceptible wild type rice plant. The simultaneous expression of three serine PIs was apparent from SHM-11 and two of them were induced in rice blast resistant Taebaegbyeo. One of them was induced in rice blast resistant Hwayeongbyeo while none of them were expressed in rice blast susceptible Nagdongbyeo and rice blast resistant Dongjinbyeo. Our results suggest that the expression of PI gene is rice cultivar specific and may be linked with the rice blast resistance in a specific rice mutant by the simultaneous expression of the PI genes.