• Title/Summary/Keyword: Attenuation equation

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The Bidirectional Relationship between Objective and Subjective Knowledge: Applying the Heuristic-systematic Model in Vietnamese Mobile Banking

  • Hai Nguyen Thi Thanh;Tommi Tapanainen;Yen Nguyen Thi Hoang
    • Journal of Information Technology Applications and Management
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    • v.31 no.3
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    • pp.71-92
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    • 2024
  • This study investigates the contribution of customer knowledge to customer intention to adopt mobile banking by evaluating the interaction among knowledge, perceived risk and trust, and behavioral intentions. Analysis is conducted through structural equation modelling using SPSS and AMOS and data from 783 customers representing the seven largest banks in Vietnam. Our study is the first one to find the existence of the bidirectional perspective between objective and subjective knowledge. The study further shows that the attenuation effect in the heuristic-systematic model could be used to explain the stronger influence of objective knowledge on intention compered to subjective knowledge. Our findings suggest that customer knowledge, perceived risk and trust impact the intention of mobile banking users in different manners and to different degrees. Particularly, objective customer knowledge is the most influential predictor of mobile banking adoption. Having a greater understanding of these relationships can help firms in deciding the kind of intervention that is most likely to convince customers to adopt a service.

Study on RF characteristics of voltage-controlled artificial transmission line employing periodically arrayed diodes for application to highly miniaturized wireless communication systems (초소형 무선 통신 시스템에서의 응용을 위한 주기적으로 배열된 다이오드를 이용한 전압제어형 전송선로의 RF 특성에 관한 연구)

  • Kim, Soo-Jeong;Kim, Jeong-Hoon;Jeong, Jang-Hyeon;Yun, Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.1
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    • pp.70-75
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    • 2017
  • In this paper, we studied the RF characteristics of a voltage-controlled artificial transmission line employing periodically arrayed diodes for application to highly miniaturized wireless communication systems on an MMIC (monolithic microwave integrated circuit). According to the results, the novel voltage-controlled artificial transmission line employing periodically arrayed diodes exhibited a short wave length, which was only 35.2% that of the conventional transmission line, owing to increasing capacitance. In addition, it's effective permittivity and effective propagation constant exhibited considerably higher values than those of the conventional transmission line. Furthermore, attenuation constant of the voltage-controlled artificial transmission line was far higher than that of the conventional transmission line. Using the closed-form equation, we theoretically analyzed the equivalent circuit of the voltage-controlled artificial transmission line.

Effectiveness of Wave Resonator for Secondary Undulation under Real Sea Conditions (실해역에서 공진장치를 이용한 부진동의 제어)

  • Jeong, Jin-Woo;Kim, Do-Sam;Park, Jong-Bae;An, Sung-Wook
    • Journal of Ocean Engineering and Technology
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    • v.24 no.6
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    • pp.51-60
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    • 2010
  • In this study, the performance evaluation of a conventional wave resonator at the entrance of a port or a pier against secondary undulation has been performed using 2D hydrodynamic modeling within port. A wave resonator has been designed for the attenuation of the secondary undulation induced by the long-periodic waves. The controlled performance of the wave resonator has been numerically investigated for CGWAVE MODULE of finite-element model of SMS (Surface water Modeling System) based on the elliptic mild-slope wave equation. SMS was verified though the comparisons with analytical solution performed by Ippen and Goda (1963). Also, It was confirmed that a wave resonator of a rectangular model harbor is effective enough to control the secondary undulation when it compares variation of water level with the case of no resonance system. From the above results, amplification phenomenon induced by long-period waves transferred from 1900 sec to 2100 sec when it applied a wave resonator in Busan Gamcheon Port which is a deep-sea. And it was confirmed that a wave resonator of Pohang New Port attenuates largely long-period waves which are within the range of 300 sec induced by long-period motion of the moored ship.

Reactive Acoustic Filter based on the Phase Cancellation Effect (위상 반전 현상을 이용한 덕트 소음 제거기)

  • 강종민
    • Journal of KSNVE
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    • v.9 no.3
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    • pp.600-606
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    • 1999
  • A reactive type acoustic filter is developed based on the phase cancellation effect which is occurring in the plane wave propagation through the two paths where the cross sectional areas are reversely changing. The theory is experimentally validated by the use of a cylindrical duct and an inserted hollowed cone of which vertex part is eliminated. Noise attenuation and the filtered frequency are dependent on the area variation and the effective length of the filter. Experimental comparison shows that the filtered frequencies of 1st and 2nd mode are lower than the analytical prediction due to the mass loading effects, and the 3rd mode is in good agreement. The proposed filter can be applied as an in-duct noise filter for improving the sound quality in a narrow space for various industrial applications.

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Acoustic Characteristics of Mufflers with an Extended Inlet and Outlet (입출구가 연장된 동심형 소음기의 음향해석)

  • 이준신
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.5
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    • pp.503-509
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    • 2002
  • Cylindrical chamber silencers with an extended inlet and outlet are extensively used in many application fields to reduce the propagated noise in ducts. The basic attenuation effectiveness in the low frequency region can be explained by the reactive wave action inside the expansion chamber associated with the geometric configurations of the inlet and outlet locations, and the area expansion of the jacket. In this study. an acoustic analysis is carried out for a concentric extended pipe inserted into a simple expansion chamber. An algebraic equation is derived by using the eigenfunction expansion and orthogonality principle in which the acoustic pressures and particle velocities defined on each subdivided surface are expressed by the separable coordinates. By using the proposed analytical method, transmission losses are predicted for several configurations of the concentric extended systems and they agree very well with experimental results.

The Design of Ring Resonator with Considering Effect of Coupling Gap (결합 갭의 영향을 고려한 링 공진기의 설계)

  • Oh, Teresa;Kim, Heung-Soo
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.8
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    • pp.27-35
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    • 1999
  • A radius of ring resonator is determined by the resonant frequency. Resonant frequencies of resonators with the circumference which is integer times of wave length are not same the expected. In this paper, we suggest the design method of a ring resonator with coupling gap, which has the resonant frequency of desire. The equation which can make reduction of the radius of the resonators depending on the gap space is derived by the method of transmission line analysis. The criterion is suggested to determine the radius of the resonator in accordance with relative permittivity. A ring resonator by the proposed method is as small as one-third of basic ring in size and it has the resonant frequency of desire. T-type coupling line is designed to obtain large attenuation of $S_{11}$ at pass-band. These coupling line capacitances are very lower than the gap capacitances, it does not affect the resonant frequency.

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A Study on the Simulator for the fabrication of bandpass filter for the Wide-band Codeless Division Multiple Access (광 대역 통과 필터 제작을 위한 모의 실험기)

  • 유일현
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.3
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    • pp.686-693
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    • 2004
  • We have studied a method to fabricated a Surface Acoustic Waves (SAW) filter for Wide band Codeless Division Multiple Access(WCDMA) was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and then we developed a simulator using the mathematica package. And, we can design and fabricate the Slanted finger Inter-digital Transducer (SFIT) for the purpose to decreased the ultimate rejections on side of the electrodes, and performed computer-simulation by simulator. Also, we have employed that the block weighted type Inter-digital Transduce(IDT) as input transduce of the filter and the withdrawal weighted type IDT as an output transducer of the filter in order to minimize effect of diffractions. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are $5000\AA$, and $1\lambda/4(\cong3.6{\mu}m)$, respectively. Also the width of IDT' finger and the space between IDT' finger and reflector are $1\lambda$/16 and 1\lambda$/8, respectively. Frequency response of the fabricated SAW bandpass filter has the property that center frequency is about 190MHz, bandwidth at the 3dB is probably 4MHz and out-band attenuation is -60dB approximately.

Iodine Quantification on Spectral Detector-Based Dual-Energy CT Enterography: Correlation with Crohn's Disease Activity Index and External Validation

  • Kim, Yeon Soo;Kim, Se Hyung;Ryu, Hwa Sung;Han, Joon Koo
    • Korean Journal of Radiology
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    • v.19 no.6
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    • pp.1077-1088
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    • 2018
  • Objective: To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn's disease activity index (CDAI) and externally validate quantitative CT parameters. Materials and Methods: Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson's correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI. Results: There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs. Conclusion: Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.

A closer look at the structure and gamma-ray shielding properties of newly designed boro -tellurite glasses reinforced by bismuth (III) oxide

  • Hammam Abdurabu Thabit;Abd Khamim Ismail;N.N. Yusof;M.I. Sayyed;K.G. Mahmoud;I. Abdullahi;S. Hashim
    • Nuclear Engineering and Technology
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    • v.55 no.5
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    • pp.1734-1741
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    • 2023
  • This work presents the synthesis and preparation of a new glass system described by the equation of (70-x) B2O3-5TeO2 -20SrCO3-5ZnO -xBi2O3, x = 0, 1, 5, 10, and 15 mol. %, using the melt quenching technique at a melting temperature of 1100 ℃. The photon-shielding characteristics mainly the linear attenuation coefficient (LAC) of the prepared glass samples were evaluated using Monte Carlo (MC) simulation N-particle transport code (MCNP-5) at gamma-ray energy extended from 59 keV to 1408 keV emitted by the radioisotopes Am-241, Ba-133, Cs-137, Co-60, Na-22, and Eu-152. Furthermore, we observed that the Bi2O3 content of the glasses had a significantly stronger impact on the LAC at 59 and 356 keV. The study of the lead equivalent thickness shows that the performance of fabricated glass sample with 15 mol.% of Bi2O3 is four times less than the performance of pure lead at low gamma photon energy while it is enhanced and became two times lower the perforce of pure lead at high energy. Therefore, the fabricated glasses special sample with 15 mol.% of Bi2O3 has good shielding properties in low, intermediate, and high energy intervals.

Predicting Single-hole Blast-induced Fracture Zone Using Finite Element Analysis

  • Jawad Ur Rehman;Duhee Park
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.7
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    • pp.5-19
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    • 2024
  • During the blasting process, a fracture zone is formed in the vicinity of the blast hole. Any damage that extends beyond the excavation boundary line necessitates the implementation of an additional support system to assure safety. Typically, fracture zone radius is estimated from blast hole pressure using theoretical methods due to its simplicity. However, linear charge concentration (kg/m) is used for tunnel blasting. This paper compiles Swedish experimental datasets to estimate the radius of fracture zones based on linear charge concentration. Further numerical analyses are performed in LS-DYNA for coupled single-hole blasting. The Riedel-Hiermaier-Thoma (RHT) model has been selected as the constitutive model for this investigation. The numerical model is validated against small-scale laboratory tests. Parametric studies are conducted to predict fracture zones in granite and sandstone rocks using two kinds of explosives, PETN and AFNO. The analyses evaluate ten types of blast hole sizes, ranging from 17 to 100 mm. The results indicate that granite has a larger fracture zone than sandstone, and the PETN explosive predicts more damage than ANFO. Smaller blast holes exhibit smaller fracture zones in comparison to larger blast holes. Wave propagation is more rapidly attenuated in granite than in sandstone. Subsequently, the predicted fracture zone outcomes are compared with the empirical dataset. Fracture zones of medium blast hole diameter align well with the experimental data set. A predictive equation is derived from the data set, which may be used to evaluate blast design to manage fracture zones beyond the excavation line.