• Structural Engineering and Mechanics
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• v.86 no.5
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• pp.673-686
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• 2023

Determining the properties of pile from cone penetration test (CPT) is costly, and need several in-situ tests. At the present study, two novel hybrid learning models, namely PSO-RF and HHO-RF, which are an amalgamation of random forest (RF) with particle swarm optimization (PSO) and Harris hawks optimization (HHO) were developed and applied to predict the pile set-up parameter "A" from CPT for the design aim of the projects. To forecast the "A," CPT data along were collected from different sites in Louisiana, where the selected variables as input were plasticity index (PI), undrained shear strength (S_u), and over consolidation ratio (OCR). Results show that both PSO-RF and HHO-RF models have acceptable performance in predicting the set-up parameter "A," with R² larger than 0.9094, representing the admissible correlation between observed and predicted values. HHO-RF has better proficiency than the PSO-RF model, with R² and RMSE equal to 0.9328 and 0.0292 for the training phase and 0.9729 and 0.024 for testing data, respectively. Moreover, PI and OBJ indices are considered, in which the HHO-RF model has lower results which leads to outperforming this hybrid algorithm with respect to PSO-RF for predicting the pile set-up parameter "A," consequently being specified as the proposed model. Therefore, the results demonstrate the ability of the HHO algorithm in determining the optimal value of RF hyperparameters than PSO.

• Journal of IKEEE
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• v.22 no.2
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• pp.309-315
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• 2018

A Stepped Frequency Radar(SFR) is a method of achieving high range resolution by gradually increasing the frequency of a transmitted pulse to create a wide synthetic bandwidth. However, in the case of moving target, accurate range estimation can not be performed due to the range-Doppler coupling phenomenon, so it is necessary to compensate through accurate velocity estimation. In this paper, we propose a stepped frequency radar waveform with a Coherent Pulse Train(CPT), velocity estimation results according to parameters using this method and VMD(Velocity Measurement Data) were compared and analyzed by numerical simulations.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.2
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• pp.83-92
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• 2019

Spontaneous combustion propensity of various coals of carbonization grade as a pulverized fuel of coal-fired power plant has been tested from an initial temperature of $25^{\circ}C$ to $600^{\circ}C$ by heating in an oven with air to analyze the self-oxidation starting temperature. These tests produce CPT (Cross Point Temperature), IT (Ignition temperature), and CPS (Cross Point Slope) calculated as the slope of time taken for a rapid exothermic oxidation reaction at CPT base. CPS shows a carbonization rank dependence whereby wood pellet has the highest propensity to spontaneous combustion of $20.995^{\circ}C/min$. A sub-bituminous KIDECO coal shows a CPS value of $15.370^{\circ}C/min$, whereas pet coke has the highest carbonization rank at $2.950^{\circ}C/min$. The nature of this trend is most likely attributable to a concentration of volatile matter and oxygen functional groups of coal surface that governs the available component for oxidation, as well as surface area of fuel char, and constant pressure molar heat.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.2
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• pp.163-169
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• 2006

Objectives : The study was conducted to investigate the effect of intelligence ability on attention using Continuous Performance Test (CPT). Methods : 56 children with ADHD (52 boys, 4 girls) and 41 children in normal (28 boys, 13 girls) were sampled, their age range was 7 to 15. They performed IQ test and ADHD Diagnostic System (ADS) in order to examine intelligence and attention. Participants were divided into normal group and ADHD group, average IQ level children and superior IQ level children. Then ADS variables (omission error, commission error, reaction time, reaction time deviation, response sensitivity, and response criterion) were analyzed. Results : There was no significant interaction effect between group (normal, ADHD) and intelligence (average, superior). But there was significant difference between normal group and ADHD group in omission error, commission error, reaction time deviation, and response sensitivity. Also average level IQ group had significantly showed more omission, greater reaction time deviation, and lower response sensitivity than superior level IQ group. Conclusion : ADHD group has attention deficit than normal group, and CPT is available tool to detect attention problems. These findings indicate that intelligence can contaminate inattention and cognitive impulsivity thus it compensates for attention deficit. And it suggests that intelligence effect is considered in analyzing CPT in ADHD children.

• Journal of the Korean Geotechnical Society
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• v.36 no.10
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• pp.57-71
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• 2020

Liquefaction-induced sand boils were observed during the Pohang earthquake (Moment magnitude, 5.4) on November 15, 2017, specifically in the region of agricultural fields and park areas near the epicenter. This was recorded as the first observed liquefaction phenomenon in Korea. This paper analyzes liquefaction potentials at the key sites at Pohang area. The simplified methods and current design standard were used to evaluate the occurrence of liquefaction. The seismic demand was estimated based on the NGA-WEST2 ground motion prediction equations (GMPEs). The liquefaction resistance of the ground was determined using the in-situ tests: standard penetration test (SPT) and cone penetration test (CPT). The liquefaction potentials were quantified by liquefaction potential index (LPI), which were compared with those from the previous studies.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.112-122
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• 1998

Measurement of electrical resistivity in soils has been used for many years with purpose of estimating in situ porosity or density. Recently electrical resistivity has also been used as an indicator of soil contaimination. This paper presents the result of laboratory experiment to investigate the resistivity variation in contaminated sandy soils. The results can be used with the Cone Penetrometer Test (CPT) result to analyse ground condition. In the experiment, the water content and leachate concentration of soils were controlled by groundwater and leachate, and then the resistivity measurement was made with 'STING-R1' by Advanced Geosciences Inc. In the case of using groundwater, the resistivity was in the range of over 1000${\omega}{\cdot}m$, but in the case of using polluted water by leachate, the resistivity decreased significantly down to 10~ 100${\omega}{\cdot}m$ for the same moisture content. Also the resistivity varied according to the degree of saturatrion. Therefore, if soil is contaminated by leachate, the CPT with electrical resistivity sensor might be used to investigate the contamination status and plume migration. But exact component of leachate and the pollutant concentration are still hard to identify.

• The Journal of Korean Physical Therapy
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• v.16 no.2
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• pp.44-53
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• 2004

Treadmill training is a new promising therapy in gait rehabilitation of patients with hemiplegia. The purpose of this study was to identify the effect of treadmill training on walking speed and gait endurance in patients with chronic hemiplegia. The subject of this includes twenty patients, who had suffered from chronic hemiplegia and were in the K rehabilitation center; each ten patients were randomly assigned to experimental or control group. Among twenty patients, one group of ten for experiment was treated with progressive speed increase treadmill ambulation traing besides conventional physical therapy(SITAT) while the rest ten for the controlled group was treated with conventional physical therapy(CPT) only, for 8 weeks alike. Before and after the foregoing 8 weeks training, walking velocity and gait endurance were measured to both groups. The data were analyzed by paired t-test. The results of this study are as follows; The SITAT and CPT showed the significant difference in walking velocity and gait endurance. As compared the rehabilitation of dependent varibles between the SITAT and CPT, SITAT showed the significant difference in walking velocity and gait endurance. The outcome suggest that patient with chronic hemiplegia can improve their walking velocity and gait endurance throught treadmill training.

• The Journal of Pediatrics of Korean Medicine
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• v.30 no.3
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• pp.69-77
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• 2016

Objectives This study is to investigate whether oral administration of Farfarae flos, JCT (Jeong-cheon-tang), CPT (Cheong-pye-tang) and CPK (Cheong-pye-tang- ga-kwandonghwa) will affect both the levels of serum GOT, GPT, blood urea nitrogen (BUN) and creatinine in SD rats or not, and will change body weight of the rats. Materials and Methods 18 SD rats were randomly divided into 6 groups - including a control group (vehicle 2 ml/rat), Farfarae flos water extract (extract 2 ml/rat), Farfarae flos fine powder (emulsion 2 ml/rat), JCT (extract 2 ml/rat), CPT (extract 2 ml/rat) and CPK (extract 2 ml/rat) group. The drugs were administered to rats for 2 weeks or 30 days (for control and Farfarae flos fine powder group only) and serum GOT/GPT activities and BUN/creatinine concentrations were measured. Also, the changes of body weights of each rat was measured. Results (1) Farfarae flos water extract, Farfarae flos fine powder emulsion, JCT and CPT and CPK did not cause any changes in serum GOT/GPT activities and BUN/creatinine concentrations compared to the ones in control group. (2) There are no significant changes in rats' body weight among the experimental groups during the experimental period. Conclusions Contrary to the reports on human data, 2 weeks or 30 days of oral administrations of Farfarae flos itself and decoctions containing Farfarae flos did not provoke hepatotoxicity and nephrotoxicity.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.466-475
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• 2006

Reliability analysis between safety factor and reliability index for driven and bored pile load capacity was analyzed in this study. 0.1B, Chin, De Beer, and Davisson's methods were used for determining pile load capacity by using load-settlement curve from pile load test. Each method define ultimate, yield and allowable pile load capacities. LCPC method using CPT results was performed for comparing with results of pile load test. Based on FOSM analysis using load factors, it is obtained that reliability indices for ultimate pile load capacity were higher than those of yield and allowable condition. Present safety factor 2 for yield and allowable load capacities are not enough to satisfy target reliability index $2.0\sim2.5$. However, it is sufficient for ultimate pile load capacity using safety factor 3.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.170.2-170.2
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• 2012

위성의 열진공 환경 시험은 고진공 극저온의 우주 환경을 모사하여 열제어 기능 및 임무 수행 능력을 검증하는 시험이다. 이 시험에서는 위성 주위에 부착한 방열판으로 위성 외각 온도를 변화 시켜 위성의 태양 지향 자세 또는 심우주 지향 자세를 모사하며, 이에 따른 위성의 온도 변화에 따라 지상 시험 장비로 위성의 히터 설정, 유닛 전원 형상의 변경 등을 해야한다. 또한 극고온 또는 극저온의 환경에 장시간 연속적으로 노출된 상태에서 위성의 기본적인 기능부터 영상 미션까지 검토하는 CPT 시험을 수행하며, 이 CPT 시험은 극한의 위성 상태의 시험이기 때문에 온도를 고려한 전자 시험 설계 및 24시간 위성 모니터링 시스템, 위험상황 발생 시 대처 방안 등에 대한 준비가 필요하다. 본 논문에서는 열진공 시험 시의 전자시험의 형상과 설계에 대해서 설명하고, 시험 결과에 대해서 정리하였다.