Equivalent Attenuation Research Articles

An online loop closing current calculation method for complex distribution networks considering source and load uncertainties

AbstractTo address the challenges posed by frequent source and load fluctuations in existing loop closing current calculation methods, this paper proposes an online loop closing current calculation method that considers source and load uncertainties. First, a dual‐stack dynamic monitoring system is utilized to obtain real‐time voltage and current variations before and after disturbances. Second, Thevenin's theorem is employed to build an equivalent model of the distribution network, simplifying the complex network into a combination of an independent voltage source and a series impedance. Then, the steady‐state loop closing current is calculated based on the open‐circuit voltage and equivalent impedance at both sides of the loop closing point. Next, the optimal frequency method is applied to determine the equivalent impedance and attenuation time constant at a specific frequency, achieving accurate calculation of the transient loop closing current. Finally, simulations are conducted to model the fluctuations in distributed generation and load, analysing the steady‐state and transient loop closing currents. The simulation results demonstrate that the proposed method accurately captures the effects of source and load fluctuations on the loop closing current in dynamic environments, with minimal calculation error, indicating its high practicality.

Study of Effective Atomic Number, Mass Energy Absorption Coefficient and Absorbed Dose Rate in Human Organ and Tissue Substitutes

Abstract: The effective atomic number and mass energy absorption coefficient are two essential parameters used to investigate the radiation response of composite materials of dosimetric interest in many medical applications. The effective atomic number of nine selected human tissues and eleven samples of tissue substitute materials were computed using two methods, the interpolation method and the direct method in the energy range used in brachytherapy applications (0.1-2.0) MeV. The applicability of using the effective atomic number values to investigate scatter and absorption properties of some tissue substitutes, against that of the corresponding human tissues, to validate their tissue-equivalency, is examined. The effect of partial interaction cross sections is also explicitly discussed. Further, the absorbed dose rate, for an isotropic point source, in the selected tissue samples was computed using their estimated mass energy absorption coefficient values. The obtained data are analyzed and differences in sample dose rate relative to water, for photon energies of interest, are evaluated. The results indicate that numbers of tissue substitute samples yield estimates of dose rate to within 5% of dose rate of their corresponding human tissues. The obtained results are expected to be useful in improving dose calculation accuracy in brachytherapy treatment planning or dose evaluation after treatment. Keywords: Dosimetry, Human organs and tissues, Tissue equivalent materials, Equivalent atomic number, Attenuation and absorption coefficients.

The Magnitude of Contralateral Suppression of Otoacoustic Emissions Is Ear- and Age-Dependent

The maturation of the uncrossed medial olivocochlear (UMOC) efferent remains poorly documented to date. The UMOC efferent system allows listeners to not only detect but also to process, recognize, and discriminate auditory stimuli. Its fibers can be explored non-invasively by recording the effect of contralateral acoustic stimulation (CAS), resulting in a decrease in the amplitude of transient evoked otoacoustic emissions (TEOAE). The objective of the present cross-sectional study was to investigate how the effectiveness of this system varies with age in healthy subjects aged 8 years to adulthood. For this purpose, 120 right-handed native French-speaking subjects (57 females and 63 males) were divided into five age groups of 24 subjects each: 8y–10y, 10y–11y6m, 11y6m–13y, 13y–17y, and ≥18y. TEOAE amplitudes with and without CAS were recorded. The equivalent attenuation (EA) was calculated, corresponding to the change in TEOAE amplitude equivalent to the effect generated by CAS. General linear models were performed to control for the effect of ear, sex, and age on EA. No sex effect was found. A stronger EA was consistently found regardless of age group in the right ear compared to the left. In contrast to the right ear, for which, on average, EA remained constant across age groups, an increasingly weaker TEOAE suppression effect with age was found in the left ear, reinforcing the asymmetrical functioning of the UMOC efferent system in favor of the right ear in adulthood. Further studies are needed to investigate the lateralization of the UMOC efferent system and its changes over time in cases of atypical or reversed cortical asymmetries, especially in subjects with specific learning disorders.

In Situ Measurement of Acoustic Attenuation for Focused Ultrasound Ablation Surgery Using a Boiling Bubble at the Focus.

Acoustic attenuation in the propagation path of focused ultrasound ablation surgery determines the energy loss toward the focal region and is critical to the consequent treatment outcomes. In situ non-invasive, reliable, and accurate measurement is challenging for multi-layered heterogeneous tissues within the focusing angle. A novel measurement approach is proposed and its performance is evaluated using ex vivo porcine tenderloin and bovine heart. A big boiling bubble (i.e., larger than a few millimeters in size) was produced at the focus as a strong reflector inside the tissue, and the echo amplitudes were used to determine the acoustic attenuation. Two models, acoustic ray and energy loss, were developed to derive the equivalent acoustic attenuation coefficient for a focused beam. The measured acoustic attenuation coefficients of ex vivo porcine tenderloin and bovine heart at 0.97 MHz and a thickness of 3 cm are 0.159 ± 0.002 and 0.250 ± 0.005 Np/cm, respectively, which are all within the scope of measured values in the literature. In addition, the echo amplitude is sensitive to the conditions of the propagation path, and the inverse acoustic attenuation coefficient of the silicone gel pad placed in front of the tissue sample was 0.807 ± 0.002 Np/cm, which is comparable to the measurement using the insertion substitution method, 0.766 ± 0.003 Np/cm. Our proposed approach could determine the tissue acoustic attenuation for focused ultrasound ablation surgery reliably and accurately in situ. The easy operating protocol may allow clinical translation and adoption for improved safety and efficacy.

Improving CT Quality for Complex Objects With the Novel Autoexposure Imaging of Stepped Voltage Scanning

For X-ray CT imaging of complex objects, the tube voltage is an important parameter. At fixed voltage, the complete projection cannot be obtained because the voltage does not match the equivalent attenuation thickness of the object at different CT scanning angles under the limitation of the dynamic range of the imaging system. Multivoltage exposure imaging is an effective solution. However, due to the limitation of high-voltage-regulation ripple, the imaging efficiency is very low if the voltage is adjusted frequently. Actually, for a ray detector with a wide dynamic range, the small difference in equivalent thickness between adjacent scanning angles cannot affect the imaging quality for complex objects. Therefore, this article proposes a novel autoexposure imaging method with stepped voltage scanning. First, according to the known imaging system, the voltage regulation method of stepped voltage adjustment is researched by evaluating the image quality of different thicknesses. Then, considering that stepped voltage adjustment cannot obtain the complete projection at the thinner thickness, the projections of negative logarithmic transformation (NLT), with stepped voltage and low voltage, are fused to obtain the high dynamic range (HDR) projection. Finally, the method is validated on both a customized titanium specimen and an actual engine blade. The results show that the proposed method can achieve HDR CT imaging of complex objects with higher quality and clearer edge details. Additionally, this new scanning mode of stepped voltage adjustment can reduce the frequency of voltage adjustment and improve imaging efficiency.

Tissue equivalence of 3D printing materials with respect to attenuation and absorption of X-rays used for diagnostic and interventional imaging.

Three-dimensional printing is a promising technology to produce phantoms for quality assurance and dosimetry in X-ray imaging. Crucial to this, however, is the use of tissue equivalent printing materials. It was thus the aim of this study to evaluate the properties of a larger number of commercially available printing filaments with respect to their attenuation and absorption of X-rays. Apparent kerma attenuation coefficients (AKACs) and absorbed doses for different X-ray spectra (tube voltages, 70-140kV) were measured and simulated by Monte-Carlo computations for a larger number of fused-deposition-modeling (FDM) materials. The results were compared with the respective values simulated for reference body tissues. In addition, the properties of polylactide acid samples printed with reduced infill densities were investigated. Measured and simulated AKACs and absorbed doses agreed well with each other and in case of AKACs also with attenuation coefficients derived from the reference database of the National Institute of Standards and Technology (NIST). For lung, adipose, muscle, and bulk soft tissue as well as for spongiosa (cancellous bone), printed materials with equivalent attenuation as well as absorption properties could be identified. In contrast, none of the considered printed materials was equivalent to cortical bone. Several FDM materials have been identified as well-suited substitutes for body tissues in terms of the investigated material characteristics. They can therefore be used for in-house production of individualized and task-specific phantoms for image quality assessment and dose measurements in X-ray imaging.

Emergence of Exceptional Points in Periodic Metastructures With Hidden Parity-Time Symmetric Defects

Abstract We study the elastodynamics of a periodic metastructure incorporating a defect pair that enforces a parity-time (PT) symmetry due to judiciously engineered imaginary impedance elements—one having energy amplification (gain) and the other having an equivalent attenuation (loss) mechanism. We show that their presence affects the initial band structure of the periodic Hermitian metastructure and leads to the formation of numerous exceptional points (EPs) which are mainly located at the band edges where the local density of modes is higher. The spatial location of the PT-symmetric defect serves as an additional control over the number of emerging EPs in the corresponding spectra as well as the critical non-Hermitian (gain/loss) strength required to create the first EP—a specific defect location minimizes the critical non-Hermitian strength. We use both finite element and coupled-mode-theory-based models to investigate these metastructures and use a time-independent second-order perturbation theory to further demonstrate the influence of the size of the metastructure and the PT-symmetric defect location on the minimum non-Hermitian strength required to create the first EP in a band. Our findings motivate feasible designs for the experimental realization of EPs in elastodynamic metastructures.

A filament 3D printing approach for CT-compatible bone tissues replication

PurposeThe aim of this study is the development of a methodology for manufacturing 3D printed anthropomorphic structures, which mimic the X-ray properties of the human bone tissue. MethodsA mixing approach of two different materials is proposed for the fabrication of a radiologically equivalent hip bone for an anthropomorphic abdominal phantom. The materials employed for the phantom were polylactic acid (PLA) and Stonefil, while a custom-made dual motor filament extrusion setup and a custom-made software associating medical images directly with the 3D printing process were employed. ResultsThree phantoms representing the hip bone were 3D printed utilizing two filaments under three different printing scenarios. The phantoms are based on a patient’s abdominal CT scan images. Histograms of CT scans of the printed hip bone phantoms were calculated and compared to the original patient’s hip bone histogram, demonstrating that a constant mixing composition of 30% Stonefil and 70% PLA with 0.0375 extrusion rate per voxel (93.75% flow for fulfilling a single voxel) for the cancellous bone, and using 100% Stonefil with 0.04 extrusion rate per voxel (100% flow) for the cortical bone results in a realistic anatomy replication of the hip bone. Reproduced HU varied between 700 and 800, which are close to those of the hip bone. ConclusionsThe study demonstrated that it is possible to mix two different filaments in real-time during the printing process to obtain phantoms with realistic and radiographically bone tissue equivalent attenuation. The results will be explored for manufacturing a CT-compatible abdominal phantom.

An overview of the applicability of SNI IEC 61331-1:2016 on Lead apron for medical use

The use of lead apron for radiation protection is regulated under the Indonesia Nuclear Regulatory Agency (BAPETEN) Decree no. 8 year 2011 about Radiation Safety and the Use of Diagnostic and Interventional Radiological X-Ray Machine. It listed the apron specifications are as follows: having thickness equivalent to 0.2 mm Pb or 0.25 mm Pb for diagnostic use and equivalent to 0.35 mm Pb or 0.5 mm Pb for interventional use. Further, National Standardization Agency (BSN) had issued SNI IEC 61331-1:2016, providing guidance for testing the plate materials on the apron using 400 kV x-ray machine and 1.3 MeV gamma exposure with narrow beam, to measure the attenuation ratio and air kerma rate. The method used is to determine the attenuation ratio, build-up factors, and equivalent attenuation coefficient. There were 4 different aprons (A, B, C, and D) with 9 measurement points. The results showed the air kerma rate without apron was 0.664 mGy/second, the air kerma rate with lead-equivalent layer was 0.0006 mGy/second, and the best result was produced using the apron C, with the attenuation ratio ranging from 17.2 to 29.1, showing the most homogeneity.

Модели искажений сигналов при распространении в лесных массивах

Models of signal propagation in forests are presented, based on the representation of forests as a continuous quasi-homogeneous medium and characterized by an effective complex permittivity. The values of the effective permittivity are a functional of the total volumetric concentration of the components of vegetation relative to the main medium - the atmosphere, of the frequency of signals, of the electrical and taxometric characteristics of forests. It is shown that when propagating along the lines under consideration, the spectral components of digital signals acquire partial phase and amplitude shifts, which causes distortions of the complex envelopes of signals and energy losses during reception with respect to propagation in free space. Modeling was carried out using models of signal propagation in forests with typical characteristics to estimate the probabilistic characteristics of receiving digital signals with 4-level phase shift keying with frequency band extension. It is shown that for these signals with a frequency band of 10...20 MHz with a center frequency of the P-band with horizontal polarization, the energy loss with respect to propagation in free space with equivalent attenuation exceeds 1.2 dB due to the distortion of the complex envelopes of the signals. A smaller effect on the probabilistic characteristics of receiving signals with vertical polarization is also shown - the energy loss in this case reaches 0.5 dB.

Relative Enhancement Ratio of Portal Venous Phase to Unenhanced CT in the Diagnosis of Lipid-poor Adrenal Adenomas.

Background The development of an accurate, practical, noninvasive, and widely available diagnostic approach to characterize lipid-poor adrenal lesions (greater than 10 HU at unenhanced CT) remains an ongoing demand. Purpose To investigate whether combined assessment of unenhanced and portal venous phase CT allows for the differentiation of lipid-poor adrenal adenomas from nonadenomas. Materials and Methods Patients with lipid-poor adrenal lesions who underwent unenhanced and portal venous phase CT with a single-energy scanner between January 2016 and March 2020 were identified retrospectively. For each lesion, the unenhanced and contrast-enhanced attenuation were measured; the absolute enhancement (contrast-enhanced minus unenhanced attenuation [HU]) and relative enhancement ratio ([absolute enhancement divided by unenhanced attenuation] × 100%) were calculated. The sensitivity achieved at 95% specificity to distinguish adenomas from nonadenomas was determined with receiver operating characteristic curve analysis and compared among parameters with use of the McNemar test. Results A total of 220 patients (mean age ± standard deviation, 66 years ± 12; 134 men) with 131 lipid-poor adenomas and 89 nonadenomas were analyzed. The sensitivity (achieved at 95% specificity) of the relative enhancement ratio (86% [113 of 131 adenomas; 95% CI: 79, 92] at a threshold of >210%) was higher than that of unenhanced attenuation (50% [66 of 131 adenomas; 95% CI: 42, 59] at a threshold of ≤21 HU), contrast-enhanced attenuation (3% [four of 131 adenomas; 95% CI: 1, 8] at a threshold of >120 HU), and absolute enhancement (24% [32 of 131 adenomas; 95% CI: 17, 33] at a threshold of >74 HU; all P < .001). The sensitivities of the relative enhancement ratio were 100% (58 of 58 adenomas; 95% CI: 94, 100), 83% (52 of 63 adenomas; 95% CI: 71, 91), and 30% (three of 10 adenomas; 95% CI: 7, 65) for adenomas measuring unenhanced attenuation of more than 10 HU up to 20 HU, 21-30 HU, and more than 30 HU, respectively. Conclusion A relative enhancement ratio threshold of greater than 210%, measured at unenhanced and portal venous phase CT, accurately differentiated lipid-poor adenomas from nonadenomas, particularly for lesions with unenhanced attenuation of 10-30 HU. © RSNA, 2021 Online supplemental material is available for this article.

On the generation and decay of the long-period coda energy of large earthquakes

Seismic coda wave is the tail portion of the earthquake record after main arrivals. Studies on the coda usually focus on high-frequency data within several hours after regional events and attribute them to the scattering effect of the heterogeneities inside the earth. Here, we use records of seven large earthquakes at globally distributed seismic stations to examine the decay of long-period (100 s to 300 s) coda in the time window of 10,000 s to 140,000 s after the origin time and fit it with a statistical model. The geometric spreading effect in the estimated initial energy and a location-independent equivalent attenuation coefficient indicate that the long-period coda energy is less affected by the heterogeneity-induced scattering effect than that of shorter-period coda. The coda energy can reach the earth’s inner core and can be explained by a 1D earth model, making it more effective for constraining the global attenuation model. It also has the potential to determine the magnitudes of large earthquakes and to explore the interior of planetary bodies.

Medial olivocochlear reflex effects on amplitude growth functions of long- and short-latency components of click-evoked otoacoustic emissions in humans.

Functional outcomes of medial olivocochlear reflex (MOCR) activation, such as improved hearing in background noise and protection from noise damage, involve moderate to high sound levels. Previous noninvasive measurements of MOCR in humans focused primarily on otoacoustic emissions (OAEs) evoked at low sound levels. Interpreting MOCR effects on OAEs at higher levels is complicated by the possibility of the middle-ear muscle reflex and by components of OAEs arising from different locations along the length of the cochlear spiral. We overcame these issues by presenting click stimuli at a very slow rate and by time-frequency windowing the resulting click-evoked (CE)OAEs into short-latency (SL) and long-latency (LL) components. We characterized the effects of MOCR on CEOAE components using multiple measures to more comprehensively assess these effects throughout much of the dynamic range of hearing. These measures included CEOAE amplitude attenuation, equivalent input attenuation, phase, and slope of growth functions. Results show that MOCR effects are smaller on SL components than LL components, consistent with SL components being generated slightly basal of the characteristic frequency region. Amplitude attenuation measures showed the largest effects at the lowest stimulus levels, but slope change and equivalent input attenuation measures did not decrease at higher stimulus levels. These latter measures are less commonly reported and may provide insight into the variability in listening performance and noise susceptibility seen across individuals.NEW & NOTEWORTHY The auditory efferent system, operating at moderate to high sound levels, may improve hearing in background noise and provide protection from noise damage. We used otoacoustic emissions to measure these efferent effects across a wide range of sound levels and identified level-dependent and independent effects. Previous reports have focused on level-dependent measures. The level-independent effects identified here may provide new insights into the functional relevance of auditory efferent activity in humans.

Quantitative Synthesis to Tracking Error Problem Based on Nominal Sensitivity Formulation

This brief presents a simple and robust design technique based on quantitative feedback theory (QFT) to solve the tracking error specification (TES) problem. The TES problem is converted into an equivalent disturbance attenuation (EDA) problem wherein the plant uncertainties are translated into equivalent external disturbance sets. The design problem then becomes a simple nominal disturbance rejection problem. The main advantage of the proposed technique is that they are simple, computationally efficient, and require less control effort (overdesign) due to the nominal sensitivity function formulation. The computational simplicity of the proposed methods makes them potentially more suitable for handling design problems involving a large number of uncertain plant parameters. Experiments are conducted on a laboratory electro-mechanical plant emulator system to demonstrate the efficacy of the proposed design method.

An improved single-ended frequency-domain-based fault detection scheme for MMC-HVDC transmission lines

Aiming at the problems currently existing in transmission line protection for modular multilevel converter (MMC) based high voltage direct current (HVDC) grids, this paper proposes an improved single-ended fault detection scheme for MMC-HVDC transmission lines. The proposed scheme is based on the frequency-domain attenuation rate of the initial voltage traveling wave (IVTW). Firstly, the values of the IVTWs generated by the internal and external faults are calculated respectively based on the equivalent model of the four-terminal MMC-HVDC grid. Due to the boundary effect of DC inductors installed on both ends of DC lines, the attenuation rates of IVTWs with the increase of the frequency under internal and external faults have different characteristics. The detail coefficients of the IVTW in different frequency bands are extracted by stationary wavelet transform at different scales, and the amplitudes of the IVTW in different frequency bands are quantified by wavelet transform modulus maximums (WTMMs) at corresponding scales. A criterion for identifying internal and external faults is constructed based on the square of the frequency-domain equivalent attenuation rate of the IVTW. Lastly, simulation results under diverse fault conditions verify the effectiveness of the proposed fault detection scheme.

Theoretical analysis of equivalent hydrostatic stress attenuation in surrounding rocks after excavation

Energy concentration and redistribution are always accompanied by tunnel deformation and failure. This study uses a plain-strain model of circular openings under high in situ stress to derive the energy of the surrounding rocks before and after excavation based on elasticity. The study focuses on determining the areal extent of the surrounding rock significantly affected by the excavation. The relationship between dimensionless zonal radius ri/a and dimensionless stress σ0/R0 is determined based on two principles: (1) energy conservation and (2) the logarithmic relationship between consumed energy and the scale of fragmentation. The law of attenuation of stress in surrounding rock during the process of zonal fracture is theoretically explained. Preliminary values for the unknown parameters in the given formula are proposed using the data available, and the stress attenuation law corresponding to the given tunnels is presented.

Characteristics of Eddy Current Attenuation and Thickness Measurement of Metallic Plate

In eddy current testing, the law of attenuation of eddy current (EC) is of great concern. In conductive half space under the excitation of uniform magnetic field, the EC density decreases exponentially in the depth direction. However, in conductor with finite thickness tested by coil, the distribution of EC in the depth direction is more complicated. This paper studies the characteristics of EC attenuation in metallic plate of finite thickness. Simulation results show that there is an EC reflection at the bottom of plate, which changes the law of EC attenuation. A new concept, namely the equivalent attenuation coefficient, is proposed to quantify the speed of EC attenuation. The characteristics of EC attenuation are utilized to explain the nonmonotonic relation between coil voltage and plate thickness. Procedure of selecting frequency is discussed. Thereafter, measurement of plate thickness is carried out and accurate result is obtained.

Bioactive glasses and the impact of Si3N4 doping on the photon attenuation up to radiotherapy energies

Bioactive glass-ceramic is a promising candidate for medical implants. The impact of Si3N4 doping on the photon attenuation properties of a newly designed bioactive glass system with the chemical composition of (55–3×)SiO2 –13.5CaO–29Na2O–2.5P2O5–xSi3N4, where x = 0, 1.76, 3.56, 5.35, and 7.17 mol%, is studied. Mass attenuation coefficient (μ/ρ) of these samples is calculated by Geant4 toolkit at photon energies ranging from 0.015 MeV up to radiotherapy energy limit namely: 10 MeV. The generated data of μ/ρ are verified using the calculated values of XCOM software. Half value layer (HVL), electron density (Neff), and effective atomic number (Zeff) are obtained for each bioactive glass involved. It is noted that HVL of these bioactive glasses increases by increasing Si3N4 content. Consequently, GP4 bioactive glass possesses the highest HVL values among the studied samples. The photon attenuation properties of GP4 glass are compared with different types of bioactive glasses and commercial glasses in terms of mean free path (MFP). Moreover, exposure and energy absorption buildup factors (EBF and EABF) are calculated for the GP4 bioactive glass at different penetration depths such as 1, 5, 10, 15, 20, 30, and 40 mfp. Additionally, removal cross section (∑R) of the present bioactive glasses is calculated. It can be concluded that GP bioactive glasses have equivalent photon attenuation properties to those of the standard bioactive glasses. Therefore, they can be safely used as an international alternative in various applications even if the exposure to gamma-ray is possible.

Global Diagnostics of Ionospheric Absorption During X‐Ray Solar Flares Based on 8‐ to 20‐MHz Noise Measured by Over‐the‐Horizon Radars

AbstractAn analysis of noise attenuation during 80 solar flares between 2013 and 2017 was carried out at frequencies 8–20 MHz using 34 Super Dual Auroral Radar Network radars and the EKB ISTP SB RAS radar. The attenuation was determined on the basis of noise measurements performed by the radars during the intervals between transmitting periods. The location of the primary contributing ground sources of noise was found by consideration of the propagation paths of radar backscatter from the ground. The elevation angle for the ground echoes was determined through a new empirical model. It was used to determine the paths of the noise and the location of its source. The method was particularly well suited for daytime situations, which had to be limited for the most part to only two crossings through the D region. Knowing the radio path was used to determine an equivalent vertical propagation attenuation factor. The change in the noise during solar flares was correlated with solar radiation lines measured by GOES/XRS, GOES/EUVS, SDO/AIA, SDO/EVE, SOHO/SEM, and PROBA2/LYRA instruments. Radiation in the 1 to 8 Å and near 100 Å are shown to be primarily responsible for the increase in the radionoise absorption, and by inference, for an increase in the D and E region density. The data are also shown to be consistent with a radar frequency dependence having a power law with an exponent of −1.6. This study shows that a new data set can be made available to study D and E regions.

A Robust Controller for Multivariable Model Matching System Utilizing a Quantitative Feedback Theory: Application to Magnetic Levitation

This paper proposes a systematic feedback controller design methodology for multi-input multi-output (MIMO) uncertain systems using the quantitative feedback theory (QFT). To achieve this goal, the model matching problem was considered and the inversion feedforward controller was designed to improve control performance while reducing the demand on feedback control alone. The proposed method is formulated based on the concept of equivalent disturbance attenuation (EDA) approach in which the uncertain system problem is converted into an external disturbance rejection problem based on a nominal system. This proposed approach exhibiting non-sequential design method result in the suboptimal solution showing design simplicity and computational efficiency compared to the existing method. In order to validate the effectiveness of the proposed control methodology, the MIMO magnetic levitation system as adopted and control performances such as time response were presented in both time and frequency domains.