• Geomechanics and Engineering
• /
• 제36권2호
• /
• pp.111-119
• /
• 2024

In the realm of rock excavation projects, precise estimation of the drilling rate index stands as a pivotal factor in strategic planning and cost assessment. This study introduces and evaluates two pioneering computational intelligence models designed for the prognostication of the drilling rate index, a pivotal parameter with direct implications for cost estimation in rock excavation projects. These models, denoted as the Relevance Vector Regression (RVR) optimized with the Invasive Weed Optimization algorithm (IWO) (RVR-IWO model) and the RVR integrated with the Shuffled Frog Leaping algorithm (SFL) (RVR-SFL model), represent a groundbreaking approach to forecasting drilling rate index. The RVR-IWO and RVR-SFL models were meticulously devised to harness the capabilities of computational intelligence and optimization techniques for drilling rate index estimation. This research pioneers the integration of IWO and SFL with RVR, constituting an unprecedented effort in forecasting drilling rate index. The primary objective of this study was to gauge the precision and dependability of these models in forecasting the drilling rate index, revealing significant distinctions between the two. In terms of predictive precision, the RVR-IWO model emerged as the superior choice when compared to the RVR-SFL model, underscoring the remarkable efficacy of the Invasive Weed Optimization algorithm. The RVR-IWO model delivered noteworthy results, boasting a Variance Account for (VAF) of 0.8406, a Mean Squared Error (MSE) of 0.0114, and a Squared Correlation Coefficient (R²) of 0.9315. On the contrary, the RVR-SFL model exhibited slightly lower precision, yielding an MSE of 0.0160, a VAF of 0.8205, and an R2 of 0.9120. These findings serve to highlight the potential of the RVR-IWO model as a formidable instrument for drilling rate index prediction, particularly within the framework of rock excavation projects. This research not only makes a significant contribution to the realm of drilling engineering but also underscores the broader adaptability of the RVR-IWO model in tackling an array of challenges within the domain of rock engineering. Ultimately, this study advances the comprehension of drilling rate index estimation and imparts valuable insights into the practical implementation of computational intelligence methodologies within the realm of engineering projects.

• 한국재료학회지
• /
• 제33권9호
• /
• pp.372-376
• /
• 2023

Transparent conductive tungsten (W) doped indium oxide (In₂O₃; IWO) films were deposited at different substrate bias voltage (-V_b) conditions at room temperature on glass substrates by radio frequency (RF) magnetron sputtering and the influence of the substrate bias voltage on the optical and electrical properties was investigated. As the substrate bias voltage increased to -350 V_b, the IWO films showed a lower resistivity of 2.06 × 10^-4 Ωcm. The lowest resistivity observed for the film deposited at -350 V_b could be attributed to its higher mobility, of 31.8 cm²/Vs compared with that (6.2 cm²/Vs) of the films deposited without a substrate bias voltage (0 V_b). The highest visible transmittance of 84.1 % was also observed for the films deposited at the -350 V_b condition. The X-ray diffraction observation indicated the IWO films deposited without substrate bias voltage were amorphous phase without any diffraction peaks, while the films deposited with bias voltage were polycrystalline with a low In₂O₃ (222) diffraction peak and relatively high intensity (431) and (046) diffraction peaks. From the observed visible transmittance and electrical properties, it is concluded that the opto-electrical performance of the polycrystalline IWO film deposited by RF magnetron sputtering can be enhanced with effective substrate bias voltage conditions.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2012년도 춘계학술발표대회
• /
• pp.109.1-109.1
• /
• 2012

본 연구에서는 co-sputtering을 통한 $WO_3$와 $In_2O_3$ 타겟을 사용하여 $WO_3$ 파워에 따른 Tungsten(W)-doped $In_2O_3$ (IWO) 투명 전극의 전기적, 광학적, 구조적 특성을 연구하고 이를 활용한 유기태양전지(Organic Photovoltaics; OPVs)의 특성을 분석하였다. Tungsten의 doping 농도는 $WO_3$에 인가되는 Radio-frequency (RF) power를 5~30 W 까지 변화시켜 조절하였으며, Rapid Thermal Annealing (RTA) 후 열처리 공정을 통해 IWO 박막의 전기적, 광학적, 구조적 특성을 분석하였다. Hall measurement 및 UV/Vis spectrometry 분석을 통하여 가시광선 영역에서 80% 이상의 높은 투과율, $48\;cm^2\;V^{-1}\;s^{-1}$의 홀 이동도, 20 ${\Omega}/{\Box}$ 이하의 낮은 면저항과 $3.2{\times}10^{-4}\;{\Omega}-cm$의 비저항 값을 나타내었다. 최적화된 IWO 박막을 이용한 OPV 셀 특성은 fill factor(FF): 61.59 %, short circuit current($J_{SC}$): 8.84 $mA/cm^2$, open circuit voltage($V_{OC}$): 0.60 V, efficiency(PCE): 3.27 %로 ITO로 제작된 OPV 샘플과 비교하였을 때 ITO를 대체할 수 있는 고이동도의 새로운 투명 전극 재료로서의 가능성을 확인하였다.

• 열처리공학회지
• /
• 제36권5호
• /
• pp.298-302
• /
• 2023

Transparent and conducting tungsten (W) doped indium oxide (IWO) thin films were deposited on the glass substrate by using RF magnetron sputtering and then electron irradiation was conducted to investigate the effect of electron irradiation on the optical and electrical properties of the films. The electron irradiated films showed three x-ray diffraction peaks of the In₂O₃ (222), (431) and (046) planes and the full width at half maximum values are decreased as increased electron irradiation energy. In the atomic force microscope analysis, the surface roughness of as deposited films was 1.70 nm, while the films electron irradiated at 700 eV, show a lower roughness of 1.28 nm. In this study, the figure of merit (FOM) of as deposited films is 2.07 × 10^-3 Ω^-1, while the films electron irradiated at 700 eV show the higher FOM value of 5.53 × 10^-3 Ω^-1. Thus, it is concluded that the post-deposition electron beam irradiation is the one of effective methods to enhance optical and electrical performance of IWO thin films.

• Steel and Composite Structures
• /
• 제45권2호
• /
• pp.205-218
• /
• 2022

Proper calculation of splitting tensile strength (STS) of concrete has been a crucial task, due to the wide use of concrete in the construction sector. Following many recent studies that have proposed various predictive models for this aim, this study suggests and tests the functionality of three hybrid models in predicting the STS from the characteristics of the mixture components including cement compressive strength, cement tensile strength, curing age, the maximum size of the crushed stone, stone powder content, sand fine modulus, water to binder ratio, and the ratio of sand. A multi-layer perceptron (MLP) neural network incorporates invasive weed optimization (IWO), cuttlefish optimization algorithm (CFOA), and electrostatic discharge algorithm (ESDA) which are among the newest optimization techniques. A dataset from the earlier literature is used for exploring and extrapolating the STS behavior. The results acquired from several accuracy criteria demonstrated a nice learning capability for all three hybrid models viz. IWO-MLP, CFOA-MLP, and ESDA-MLP. Also in the prediction phase, the prediction products were in a promising agreement (above 88%) with experimental results. However, a comparative look revealed the ESDA-MLP as the most accurate predictor. Considering mean absolute percentage error (MAPE) index, the error of ESDA-MLP was 9.05%, while the corresponding value for IWO-MLP and CFOA-MLP was 9.17 and 13.97%, respectively. Since the combination of MLP and ESDA can be an effective tool for optimizing the concrete mixture toward a desirable STS, the last part of this study is dedicated to extracting a predictive formula from this model.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권5호
• /
• pp.1912-1931
• /
• 2018

In future wireless network, user experience and energy efficiency will play more and more important roles in the communication systems compared to their roles at present. Quality of experience (QoE) and Energy Efficiency (EE) become the widely used metrics. In this paper, we study a combinatorial problem of QoE and EE and investigate a fair power allocation in heterogeneous networks. We first design a new metric, QoE-aware EE (QEE) to reflect the relationship of QoE and energy. Then, the concept of Utopia QEE is introduced, which is defined as the achievable maximum QEE in ideal conditions, for each user. Finally, we transform the power allocation process to an optimization of ratio of QEE and Utopia QEE and use invasive weed optimization (IWO) algorithm to solve the optimization problem. Numerical simulation results indicate that the proposed algorithm can get converged and efficiently improve the system energy efficiency and the QoE for each user.

• 한국전자파학회논문지
• /
• 제25권5호
• /
• pp.592-600
• /
• 2014

본 논문에서는 2차 함수 곡선의 회전체 곡면 위에 있는 배열 안테나의 빔 합성을 위한 Enhanced Adaptive Genetic Algorithm(EAGA)을 제안하였다. 제안된 알고리즘은 더 빠른 수렴 속도와 더 낮은 비용함수 값을 얻기 위해 Adaptive Genetic Algorithm(AGA)과 Invasive Weed Optimization(IWO)을 결합시켰다. 각 안테나 소자의 급전 크기와 위상의 최적화된 값은 EAGA를 통해 구하였으며, 이 결과를 통해 EAGA가 컨포멀 배열 안테나의 패턴 합성 알고리즘으로써 AGA보다 더 우수함을 보였다.

• 한국동물학회지
• /
• 제33권1호
• /
• pp.103-107
• /
• 1990

BSA로 면역시킨 드렁허리의 혈청에서 lgM 유사면역글로불린의 정제한 후 그 구조적 특성을 구명하였다. 면역후 항혈청에서는 항원특이 항체능이 증가되었다. 정제된 lgM 유사면역글로불린은 199kD의 분자량을 갖는 단량체 4개가 결합된 800kD의 단백질이었으며, 단량체는 70kD인 H-사슬 2개와 29.5kD인 L-사슬 2개가 결합된 형태였다. 또한 드렁허리의 lgM 유사면역글로불린은 lgM의 특성과 같이 포유류 적혈구에 대하여 약한 응집력을 나타냈다.

• 한국응용곤충학회지
• /
• 제33권3호
• /
• pp.141-147
• /
• 1994

Deosophila melanogadter 자연집단재 alcohol dehydrogenase(ADH) allele 의 polymorphism 및 두 ADH allele 유전자형간의 적응도와 ethanol 의 상관 관계를 조사하였다. D. meanogaster의 자연집단내 ADH는 polymorphic 하였으며, FF,FS그리고 SS형의 유전자 빈도는 47.66,42.18 및 10.16%로 나타나 F 유전자의빈도가 S 유전자에 비하여 높게 분포하였다. 산란력과 우화율에서는 FF 유전자형이 SS 유전자형에 비하여 모두 약간 높게 나타났다. 자연집단에서 유래된 인공 소집단에서는 세대의 흐름에 따라 {{{{ { Adh}^{F } }}}} 유 전자형의 빈도증가와 상대적 {{{{ { Adh}^{S }}}}} 유전자형의 감소를 보였고, etha-nol은 ADH locu 상의 selective factor로서 작용함을 시사하여 주었다.

• 자원리싸이클링
• /
• 제4권3호
• /
• pp.2-9
• /
• 1995

탈황 폐촉매 중에 함유되어 있는 Ni, V 및 Mo을 배소, 암모니아 침출 및 용매추출법을 이용하여 분리.회수하는 프로세스에 대하여 연구하였다. 폐촉매를 $400^{\circ}C$로 3시간 동안 배소한 후, 20mesh 이하로 분쇄하여, 고액비 50g/d㎥의 조건에서 100g/d㎥-(NH$_4$)$_2$CO$_3$를 침출제로 하여 $80^{\circ}C$에서 침출한 결과 Ni, V 및 Mo의 침출율은 각각 81.2%, 65%, 87.5%이었다. 이 침출액을 방냉하면 침출액 중의 74%의 V이 바나듐산 나트륨염의 형태로 침전되어 순도 95.7%의 V을 회수할 수 있었다. 1차 침출 후의 잔사에$ Na_2$$CO_3$를 가하여 $1000^{\circ}C$에서 재차 배소한 후, 온수에 침출하여 잔존된 Mo과 V을 95%이상 침출되었다. 1차 침출액 중의 Ni, V 및 Mo을 용매추출법으로 분리.정제하였다. 용액 중의 Ni는 MSP-8, V은 TOMAC을 추출제로 하여 추출.분리하고 Mo은 raffinate로 분리하였다. Batch 추출에 의하여 Ni은 95%, V은 98%가 유기상에 추출되었으며, 역추출액에 환원제를 첨가하여 순도 99%이상의 V을 회수하였다.