• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.7C
• /
• pp.665-671
• /
• 2006

In this paper, we propose and observe a system that adopts Independent-MCS (Modulation and Coding Scheme) level for each layer in the combined AMC-V-BLAST (Adaptive Modulation and Coding-Vertical-Bell-lab Layered Space-Time) system. Also, comparing with the combined system using Common-MCS level, we observe throughput performance improvement. As a result of simulation, Independent-MCS level case adapts modulation and coding scheme for maximum throughput to each channel condition in separate layer, resulting in improved throughput compared to Common-MCS level case. Especially, the results show that the combined AMC-V-BLAST system with Independent-MCS level achieves a gain of 700kbps in $7dB{\sim}9dB$ SNR (Signal-to-Noise Ratio) range.

• Journal of KSNVE
• /
• v.8 no.5
• /
• pp.821-831
• /
• 1998

The actual ground vibrations due to NATM and foundation blasting at Seoul(weathered rock), Pusan(weathered rock) and Youngkwang(quartz andesite) have been measured, and the data were analyzed using reliability index($\beta$) to determinate the vibration equations and the maximum charge weight for efficient blast. These were suggested with the division of ultimate limit state($\beta$=0), serviceability limit state($\beta$=1.28) and safety state($\beta$=3), respectively. The reliability index 0 mean 50% data line obtained by the least squares best-fit line. The reliability index 1.28 and 3 represent bounds below 90% and 99.9% of the data, respectively. In this study, reliability index $\beta$=1.28 with security and economy was suggested. The maximum charge weight equations for efficient blast were obtained in W=(Vc/384.90)1.5151.D3(Seoul), W=(Vc/579.82)1.4706.D3(Pusan). W=(Vc/1654.01)1.3456.D3(Youngkwang), and the blast vibration equatiions in V=385(SD)-1.98(Seoul), V=580(SD)-2.04(Pusan), V=1654(SD)-2.23(Youngkwang), respectively. From this study, inference and analysis methods of vibration equations using reliability theory were established.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.605-608
• /
• 2008

We have studied statistically about quality difference of Blast furnace slag Type Ⅲ that affects carbonation of concrete. According to KS F 2563 blast furnace slag was classified 3 types. Type Ⅲ blast furnace slag(specific surface area is $4000cm^2/g$) from different providers with Type A, the B and the C. The statistical technique was applied to exclude error of engineering judgement. T test and F test were used among 3 groups to investigate statistical meaning. The effect which on the quality of blast furnace slag type Ⅲ that affects carbonation of concrete is significant.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.313-314
• /
• 2013

The study carried out the experiment with presenting as the fundamental data for developing non-cement by using red mud generated in blast furnace slag and bauxite generated in the process of manufacturing the pig iron process of manufacturing Al(OH)₃/Al₂O from as the binding material using the accelerator of NaOH. After fixing the thing and the NaOH adding the blast furnace slag and NaOH 10, 20, 30 (%) with 10, 20, 30 (%) substituted the red mud in the blast furnace slag and the experimental method carried out the experiment. And it measured the flexural strength and compressive strength and took a photograph EDS analysis and SEM. Consequently, the compressive strength was improved as the addition rate of the NaOH was high and the compressive strength according to the replacement ratio of the red mud was degraded. This is determined that film of the blast furnace slag is destroyed and it makes the hydration reaction condition and the intensity is revealed.

• Explosives and Blasting
• /
• v.41 no.3
• /
• pp.1-12
• /
• 2023

A basic assessment of techniques to mitigate the risk of blast shock waves from proximity explosions was conducted. Common existing techniques include using mitigant materials to form barriers around the explosive or in the direction of propagation of the shock wave. Various explosive energy dissipation mechanisms have been proposed, and research on blast shock wave mitigation utilizing impedance differences has drawn considerable interest. In this study, shear thickening fluid (STF) was applied as a blast mitigation material to evaluate the effectiveness of STF mitigation material on explosion shock wave mitigation through explosion experiments and numerical analysis. As a result, the effectiveness of the STF mitigant material in reducing the explosion shock pressure was verified.

• Korean Journal of Plant Resources
• /
• v.29 no.6
• /
• pp.658-669
• /
• 2016

Rice blast, caused by a fungus Magnaporthe oryzae, is one of the most devastating diseases of rice worldwide. Analyzing the valuable genetic resources is important in making progress towards blast resistance. Molecular screening of major rice blast resistance (R) genes was determined in 2,509 accessions of rice germplasm from different geographic regions of Asia and Europe using PCR based markers which showed linkage to twelve major blast R genes, Pik-p, Pi39, Pit, Pik-m, Pi-d(t)2, Pii, Pib, Pik, Pita, Pita/Pita-2, Pi5, and Piz-t. Out of 2,509 accessions, only two accessions had maximum nine blast resistance genes followed by eighteen accessions each with eight R genes. The polygenic combination of three genes was possessed by maximum number of accessions (824), while among others 48 accessions possessed seven genes, 119 accessions had six genes, 267 accessions had five genes, 487 accessions had four genes, 646 accessions had two genes, and 98 accessions had single R gene. The Pik-p gene appeared to be omnipresent and was detected in all germplasm. Furthermore, principal component analysis (PCA) indicated that Pita, Pita/Pita-2, Pi-d(t)2, Pib and Pit were the major genes responsible for resistance in the germplasm. The present investigation revealed that a set of 68 elite germplasm accessions would have a competitive edge over the current resistance donors being utilized in the breeding programs. Overall, these results might be useful to identify and incorporate the resistance genes from germplasm into elite cultivars through marker assisted selection in rice breeding.

• Steel and Composite Structures
• /
• v.27 no.6
• /
• pp.717-725
• /
• 2018

One of the most important design criteria in military tunnels and armoured doors is to resist the blast loads with minimum structural weight. This can be achieved by using steel sandwich panels. In this paper, the nonlinear behaviour of steel sandwich panels, with different core materials: (1) Hollow (no core material); (2) Rigid Polyurethane Foam (RPF); and (3) Vulcanized Rubber (VR) under free air blast loads, was investigated using detailed 3D nonlinear finite element models in Ansys Autodyn. The accuracy of the finite element model proposed was verified using available experimental test data of a similar steel sandwich panel tested. The results show the developed finite element model can be reliably used to simulate the nonlinear behaviour of the steel sandwich panels under free air blast loads. The verified finite element model was used to examine the different parameters of the steel sandwich panel with different core materials. The result shows that the sandwich panel with RPF core material is more efficient than the VR sandwich panel followed by the Hollow sandwich panels. The average maximum displacement of RPF sandwich panel under different ranges of TNT charge (1 kg to 10 kg at a standoff distance of 1 m) is 49% and 53% less than the VR and Hollow sandwich panels, respectively. Detailed empirical design equations were provided to quantify the maximum deformation of the steel sandwich panels with different core materials and core thickness under a different range of blast loads. The developed equations can be used as a guide for engineer to design steel sandwich panels with RPF and VR core material under a different range of free air blast loads.

• Journal of the Korean Geosynthetics Society
• /
• v.21 no.4
• /
• pp.111-121
• /
• 2022

It has been reported that current amount of coal ash remains almost 100 million tons and 5.85 million tons of blast furnace slag are generated annually in Vietnam. Vietnam government has encouraged the industries to increase the use of coal ash and blast furnace slag as construction materials as well as in cement production institutionally. However, limited can be applied in the construction field yet. Therefore, in this study, basic performance analysis on five different kinds of fly ash from Vietnam was conducted. In addition, the performances of blast furnace slags generated in Vietnam and Korea were compared and evaluated. Soil stabilizer compressive strength test and solidified soil unconfined compressive strength test were conducted as the basic data for the development of soil stabilizer applied to the soil mixing method using fly ash and blast furnace slag generated in Vietnam. The results showed that the Vietnamese fly ash and blast furnace slag can be used as the raw materials for soil stabilization and improvement.

• Geomechanics and Engineering
• /
• v.35 no.2
• /
• pp.121-133
• /
• 2023

The demand for cement and limestone crushed materials has increased many folds due to the tremendous increase in construction activities in Pakistan during the past few decades. The number of cement production industries has increased correspondingly, and so the rock-blasting operations at the limestone quarry sites. However, the safety procedures warranted at these sites for the blast-induced ground vibrations (BIGV) have not been adequately developed and/or implemented. Proper prediction and monitoring of BIGV are necessary to ensure the safety of structures in the vicinity of these quarry sites. In this paper, an attempt has been made to predict BIGV using artificial neural network (ANN) at three selected limestone quarries of Pakistan. The ANN has been developed in Python using Keras with sequential model and dense layers. The hyper parameters and neurons in each of the activation layers has been optimized using randomized and grid search method. The input parameters for the model include distance, a maximum charge per delay (MCPD), depth of hole, burden, spacing, and number of blast holes, whereas, peak particle velocity (PPV) is taken as the only output parameter. A total of 110 blast vibrations datasets were recorded from three different limestone quarries. The dataset has been divided into 85% for neural network training, and 15% for testing of the network. A five-layer ANN is trained with Rectified Linear Unit (ReLU) activation function, Adam optimization algorithm with a learning rate of 0.001, and batch size of 32 with the topology of 6-32-32-256-1. The blast datasets were utilized to compare the performance of ANN, multivariate regression analysis (MVRA), and empirical predictors. The performance was evaluated using the coefficient of determination (R²), mean absolute error (MAE), mean squared error (MSE), mean absolute percentage error (MAPE), and root mean squared error (RMSE)for predicted and measured PPV. To determine the relative influence of each parameter on the PPV, sensitivity analyses were performed for all input parameters. The analyses reveal that ANN performs superior than MVRA and other empirical predictors, andthat83% PPV is affected by distance and MCPD while hole depth, number of blast holes, burden and spacing contribute for the remaining 17%. This research provides valuable insights into improving safety measures and ensuring the structural integrity of buildings near limestone quarry sites.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.57-58
• /
• 2015

In this research the processing method of Desulfurized Plaster is changed to cyclotomy, 0.3mm sieve analysis and 500℃ heat exposure, and by changing the mix rate of the binding agent to 0~20%, it was applied to mortar that used cyclic aggregate and blast furnace slag for testing. The test results showed that the flow decreased in the order of cyclotomy, high heat exposure, and sieve analysis according to the mix rate of FGD, and while the air volume decreased for cyclotomy, it was shown to have almost no effect on sieve analysis and high heat exposure. The setting time accelerated as the mixing rate of FGD increased, and the compression strength increased as the mixing rate of FGD increased and especially showed a high trend with cyclotomy and sieve analysis.