• Geomechanics and Engineering
• /
• v.36 no.2
• /
• 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.

• Korean Journal of Materials Research
• /
• v.33 no.9
• /
• 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.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2012.05a
• /
• 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.

• Journal of the Korean Society for Heat Treatment
• /
• v.36 no.5
• /
• 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
• /
• v.45 no.2
• /
• 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)
• /
• v.12 no.5
• /
• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.5
• /
• pp.592-600
• /
• 2014

This paper proposes an enhanced adaptive genetic algorithm(EAGA) dedicated to pattern synthesis of array antenna which conforms to a curved surface of rotation with quadratic function. EAGA combines adaptive genetic algorithm(AGA) with invasive weed optimization(IWO) for the faster convergence and the lower cost value of the cost function. The amplitude and phase of each excited weighting factor are optimized to meet the required goals using EAGA. The EAGA results indicate that the proposed algorithm is superior to AGA when applied to the problem of conformal array antenna pattern synthesis.

• The Korean Journal of Zoology
• /
• v.33 no.1
• /
• pp.103-107
• /
• 1990

lgM-like immunoglobulin was purified from the immune serum of M albus which immunized with bovine Serum albumin(BSA) as an antigen(Ag) and characterized. The Ag-specific antibody activity of the immune serum was increased after the immunization. The purified lgM-like immunoglobulin had a tetrameric structure which had a molecular weight of 800 kD and the monomer of IgM-like Ig had a mass of 199 kD which was composed of two heavy chains (Mol. wt. 70 kD) and iwo light chains (Mol. wt. 29.5 kD). The IgM-like Ig showed hemaggluti nating activity to mammalian RBC slightly.

• Korean journal of applied entomology
• /
• v.33 no.3
• /
• pp.141-147
• /
• 1994

Tne present studies were camied out to ~nvestigate the allele frequency variations of alcohol dehydrogenase (ADH) in natural populat~ons of Drosophiio melonogoster and the correlations of iwo ADH alleles between fitness and ethanol. ADH alleles were found to be polymorphic in natural populations of D. rnelanogaster. The frequencies of FF, FS and SS genotypes were 47.66, 42 18, and 10.16%. respectively, therefore the F gene frequency (68.75) was shown to be hlgher than the S gene (31.25 %). The FF genotype was slightly superior to the SS genotype in both fecundiiy and eclaslon. The frequency of AdhF allele in the small alt>fic~apl opulaliow originated from natural populations was increased for 20 generations on normal media at 25$^{\circ}$C In resistance to ethanol, the FF genotype was supenor to the SS genotype, too. It meant that ethanol as environmental factor might be the selective factor on ADH locus in natural populat~ons of D meionogoster.

• Resources Recycling
• /
• v.4 no.3
• /
• pp.2-9
• /
• 1995

The rccoverg and separation pracess of nikcl, vanadium and molybdenum from spent dcsulfilrizing catalyst ofpetrochemical rndustries was studied. Tnis process was canied out wet process which is consist of roasting, ammonialeaching and solve111 exDaction techniqcs. The metal ions of NI, V and Mo as vduable compollents were treated byroasting them a1 low lernperatuc, 400$^{\circ}$C in first dep, and then dlssah'ed nu1 at 80$^{\circ}$C wlth ammonium cabonate mlulion.Aftcr cooling them a1 room tempertaure, vanadium wa rccavered from mathcr iiquur in thc f n m of precipitate, sodiumvanadales The Secand slep, roasting the catalyst which is added sodium carbonate ul IOOO"C, was employed. Leachingwith distilled ~ a l e rga ve a iwo phase resultant, solutio~c~a ntaning Ni, V and Mo and solid residue containing sibca,alurmniu~n and iron. A solvcnt exlclction technique uslng vvriuus extractanls, MSP-8, TOIUC, LIX64Pi was eflecnve farthc extraclion and scparation ol thrcc mcfals from thc ammonical 11qou1 thc ammonical 11qou1.