• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.325-333
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• 2006

We describe tests for detecting and locating quantitative traits loci (QTL) for traits in Hanwoo. Lod scores and a permutation test have been described. From results of a permutation test to detect QTL, we select major DNA markers of BMS1167 microsatellite locus in Hanwoo chromosome 17 for further analysis. K-means clustering analysis applied to four traits and eight DNA markers in BMS1167 resulted in three cluster groups. We conclude that the major DNA markers of BMS1167 microsatellite locus in Hanwoo chromosome 17 are markers 100bp, 108bp and 110bp.

• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.913-921
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• 2005

We describe tests for detecting and locating quantitative traits loci (QTL) for traits in Hanwoo. Lod scores and a permutation test have been described. From results of a permutation test to detect QTL, we select major DNA markers of BMS941 microsatellite locus in Hanwoo chromosome 17 for further analysis. K-means clustering analysis applied to four traits and eight DNA markers in BMS941 resulted in three cluster groups. We conclude that the major DNA markers of BMS941 microsatellite locus in Hanwoo chromosome 17 are markers 80bp, 85bp 90bp and 105bp.

• Journal of Power Electronics
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• v.17 no.2
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• pp.490-500
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• 2017

Fuel cell (FC) is a promising power supply in electric vehicles (EV); however, it has poor dynamic performance and short service life. To address these shortcomings, a super capacitor (SC) is adopted as an auxiliary power supply. In this study, the frequency decoupling control method is used in electric vehicle energy system. High-frequency and low-frequency demand power is provided by SC and FC, respectively, which makes full use of two power supplies. Simultaneously, the energy system still has rapidity and reliability. The distributed power system (DPS) of EV requires DC-DC converters to achieve the desired voltage. The stability of cascaded converters must be assessed. Impedance-based methods are effective in the stability analysis of DPS. In this study, closed-loop impedances of interleaved half-bridge DC-DC converter and phase-shifted full-bridge DC-DC converter based on the frequency decoupling control method are derived. The closed-loop impedance of an inverter for permanent magnet synchronous motor based on space vector modulation control method is also derived. An improved Middlebrook criterion is used to assess and adjust the stability of the energy system. A theoretical analysis and simulation test are provided to demonstrate the feasibility of the energy management system and the control method.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.53-59
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• 2018

In this paper, we propose a sequence mining based manufacturing process using a decision model in cognitive factory. The proposed model is a method to increase the production efficiency by applying the sequence mining decision model in a small scale production process. The data appearing in the production process is composed of the input variables. And the output variable is composed the production rate and the defect rate per hour. We use the GSP algorithm and the REPTree algorithm to generate rules and models using the variables with high significance level through t-test. As a result, the defect rate are improved by 0.38% and the average hourly production rate was increased by 1.89. This has a meaning results for improving the production efficiency through data mining analysis in the small scale production of the cognitive factory.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.385-396
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• 2020

A uniaxial compression test was performed to analyse the mechanical properties and macroscale and mesoscale failure mechanisms of sandstone with pyrite concretions. The effect of the pyrite concretions on the evolution of macroscale cracks in the sandstone was further investigated through numerical simulations with Particle Flow Code in 2D (PFC2D). The results revealed that pyrite concretions substantially influence the mechanical properties and macroscale and mesoscale failure characteristics of sandstone. During the initial loading stage, significant stress concentrations occurred around the edges of the pyrite concretion accompanied by the preferential generation of cracks. Meanwhile, the events and cumulative energy counts of the acoustic emission (AE) signal increased rapidly because of friction sliding between the concretion and sandstone matrix. As the axial stress increased, the degree of the stress concentration remained relatively unchanged around the edges of the concretions. The cracks continued growing rapidly around the edges of the concretions and gradually expanded toward the centre of the sample. During this stage, the AE events and cumulative energy counts increased quite slowly. As the axial stress approached the peak strength of the sandstone, the cracks that developed around the edges of the concretion started to merge with cracks that propagated at the top-left and bottom-right corners of the sample. This crack evolution ultimately resulted in the shear failure of the sandstone sample around the edges of the pyrite concretions.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.509-522
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• 2022

Tail-grouting is an effective measure in shield engineering for filling the gap at the shield tail to reduce ground deformation. However, the gap-filling ratio affects the value of the gap parameters, leading to different surface settlements. It is impossible to adjust the fill ratio indiscriminately to study its effect, because the allowable adjustment range of the grouting quantity is limited to ensure construction site safety. In this study, taking the shield tunnel section between Chaoyanggang Station and Shilihe Station of Beijing Metro Line 17 as an example, the correlation between the tail-grouting parameter and the surface settlement is investigated and the optimal grouting quantity is evaluated. This site is suitable for conducting field tests to reduce the tail-grouting quantity of shield tunneling over a large range. In addition, the shield tunneling under different grouting parameters was simulated. Furthermore, we analyzed the evolution law of the surface settlement under different grouting parameters and obtained the difference in the settlement parameters for each construction stage. The results obtained indicate that the characteristics of the grout affect the development of the surface settlement. Therefore, reducing the setting time or increasing the initial strength of the grout could effectively suppress the development of surface subsidence. As the fill ratio decreases, the loose zone of the soil above the tunnel expands, and the soil deformation is easily transmitted to the surface. Meanwhile, owing to insufficient grout support, the lateral pressure on the tunnel segments is significantly reduced, and the segment moves considerably after being removed from the shield tail.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.505-516
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• 2018

In this paper, the effects of particle size and model scale of concrete has been investigated on the failure mechanism of PFC2D numerical models under uniaxial compressive test. For this purpose, rectangular models with same particle sizes and different model dimensions, i.e., $3mm{\times}6mm$, $6mm{\times}12mm$, $12mm{\times}24mm$, $25mm{\times}50mm$ and $54mm{\times}108mm$, were prepared. Also rectangular models with dimension of $54mm{\times}108mm$ and different particle sizes, i.e., 0.27 mm, 0.47 mm, 0.67 mm, 0.87 mm, 1.07 mm, 1.87 mm and 2.27 mm were simulated using PFC2D and tested under uniaxial compressive test. Concurrent with uniaxial test, direct shear test was performed on the numerical models. Dimension of the models were $75{\times}100mm$. Two narrow bands of particles with dimension of $37.5mm{\times}20mm$ were removed from upper and lower of the model to supply the shear test condition. The particle sizes in the models were 0.47 mm, 0.57 mm, 0.67 mm and 0.77 mm. The result shows that failure pattern was affected by model scale and particle size. The uniaxial compressive strength and shear strength were increased by increasing the model scale and particle size.

• Tunnel and Underground Space
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• v.26 no.1
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• pp.1-11
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• 2016

This study deals with the case that was the field application of the microseismic monitoring techniques for the stability monitoring in a domestic mine. The usefulness and limitations of the microseismic techniques were examined through analyzing the microseismic monitored data. The target limestone mine adopted a hybrid room-and-pillar mining method to improve the extraction ratio. The accelerometers were installed in each vertical pillar within the test bed which has the horizontal cross-section $50m{\times}50m$. The measured signals were divided into 4 types; blasting induced signal, drilling induced signal, damage induced signal, and electric noise. The stability analysis was performed based on the measured damage induced signals. After the blasting in the mining section close to the test bed, the damage of the pillar was increased and rockfall near the test bed could be estimated from monitored microseismic data. It was possible to assess the pillar stability from the changes of daily monitored data and the proposed safety criteria from the accumulated monitored data. However, there was a difficulty to determine the 3D microseismic source positions due to the 2D local sensor arrays. Also, it was needed to use real-time monitoring methods in domestic mines. By complementing the problems encountered in the mine application and comparing microseismic monitored data with mining operations, the microseismic monitoring technique can be used as a better safety method.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.399-403
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• 2013

Mining diggers have been substituted with the robots for the mining works in dangerous and narrow tunnel, and those demands are increased in nowadays. In this study, experimental research on the remote controlled robots to perform after the development of the robot. According to the test results, performances of the developed robot and its working devices have been modified several times. It has been considered that the robot keeps its optimum performance in states as follows; driving speed 1.0 km/h, crawl angle $10^{\circ}$, spiking cycle 500bpm and breaking power $30kg_fm$. And also it has been found that sufficient cooling for the robot's working parts is essential to extend those working periods longer than 3 hours steadily under rating condition.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.25-33
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• 2015

From the viewpoint of applications to manufacturing, data mining is a useful method to find the meaningful knowledge or information about states of processes. But the data from manufacturing processes usually have two characteristics which are multicollinearity and imbalance distribution of data. Two characteristics are main causes which make bias to classification rules and select wrong variables as important variables. In the paper, we propose a new data mining procedure to solve the problem. First, to determine candidate variables, we propose the multiple hypothesis test. Second, to make unbiased classification rules, we propose the decision tree learning method with different weights for each category of quality variable. The experimental result with a real PDP (Plasma display panel) manufacturing data shows that the proposed procedure can make better information than other data mining procedures.