External Impedance Research Articles

Best impedance matching seeking of single-frequency capacitively coupled plasmas by numerical simulations

Impedance matching can maximize the absorbed power transferred to the plasma load and minimize the reflected power, making it critical and indispensable for capacitively coupled plasmas (CCPs). The external circuit usually interacts with the plasma nonlinearly, so the global simulation of the external circuit and plasma and the matching design is very challenging. In this work, an a priori model was proposed to match the plasma impedance and the external circuit impedance for single-frequency CCPs. By calculating the plasma impedance and the matching network, the matching parameters were iteratively updated to find the best matching parameters. By adjusting the capacitance and the inductance of the circuit by numerical simulations, the reflection coefficient can be significantly reduced. At the same time, the plasma power absorption efficiency will be significantly improved. The universality of the method was demonstrated by choosing different initial circuit, discharge, and plasma parameters. The proposed method provides an effective matching design reference for CCPs.

Output optimization of piezoelectric monitoring system considering loss impedance and spatial arrangement under traffic load

A widely adoption of stacked piezoelectric transducers in roads or railways health monitoring is limited by a lack of matching quantitative impedance analysis and optimal spatial arrangement. This paper proposes an equivalent circuit model of the stacked piezoelectric transducer considering loss impedance to quantify the output electrical energy. Assisted by laboratory tests, variation in loss impedance as loading amplitude and frequency is obtained, and then, is incorporated into the proposed model to calculate output of piezoelectric transducers. A numerical model is further established to assess effect of spatial arrangement on output of piezoelectric transducers combining with theoretical model and laboratory tests. It is observed that energy output of layered arrangement increases by 300% than that of flat arrangement. An increase in the transducers number not only reduces the matching impedance but also the corresponding output of piezoelectric transducers under the same traffic load. Moreover, a field test is carried out to study the external impedance output power of a stacked piezoelectric energy harvesting system. A closed comparison between theoretical and test results verifies that the proposed model with special consideration on the loss impedance can predict the output of piezoelectric transducers reasonably well, which provides a reference for optimizing the self-power health monitoring system used in roads or railways.

Research on Calculation of Rail Self-Impedance of Track Circuit Based on Partial Element Equivalent Circuit

The self-impedance of the steel rail, as the signal transmission medium in the electrified railway track circuit, has a direct impact on the track circuit’s transmission performance. The finite element method is the most common method for calculating rail impedance, although it has a number of drawbacks, including a complicated model, a long computation time, and poor accuracy. The partial element equivalent circuit (PEEC) approach is used in this paper to provide a method for determining rail self-impedance. Firstly, the rail equivalent method is determined by analyzing the physical model of the rail. Considering the skin effect, the PEEC model of the rail is established. The internal impedance of the rail can be obtained by solving the equivalent circuit. The external impedance considering the influence of the earth is calculated by the Carson impedance calculation formula, which is processed by the segmented linear approximation method. The rail’s self-impedance is determined using the two procedures together. Finally, the actual measurement data verified the PEEC method to calculate the rail impedance. Compared with the finite element method (FEM), the calculation accuracy of the PEEC method is higher. The current frequency, the height of the rail from the ground, and the earth’s conductivity impact on the rail’s self-impedance are analyzed. The results show that the PEEC technique can be used to calculate the rail’s self-impedance and that the impact of current frequency, rail height above the ground, and ground conductivity on the rail’s self-impedance may be accurately represented. The self-impedance computation of the track circuit provides a theoretical basis.

An Inverse Dynamics-Based Control Approach for Compliant Control of Pneumatic Artificial Muscles

Rehabilitation is an area of robotics in which human–robot collaboration occurs, requiring adaptation and compliance. Pneumatic artificial muscles (PAM) are soft actuators that have built-in compliance making them usable for rehabilitation robots. Conversely, compliance arises from nonlinear characteristics and generates obstructions in modeling and controlling actions. It is a critical issue limiting the use of PAM. In this work, multi-input single-output (MISO) inverse modeling and inverse dynamics model learning approaches are combined to obtain a novel nonlinear adaptive control scheme for single PAM-actuated 1-DoF rehabilitation devices, for instance, continuous passive motion (CPM) devices. The objective of the proposed system is to bring an alternative solution to the compliant operation of PAM while performing exercise trajectories, to satisfy requirements such as larger range of motion (ROM) and adaptability to external load impedance variations. The control system combines the operation of a nonlinear autoregressive network with exogenous inputs (NARX)-based inverse dynamics estimator used as a global range controller and cascade PIDs for local position and pressure loops. Implementation results demonstrated the efficacy of the introduced method in terms of compliant operation for dynamic external load variations as well as a stable operation in case of impulsive disturbances. To summarize, a simple but efficient method is illustrated to facilitate the common use of PAM.

Numerical Short-Open-Load (SOL) Calibration Technique for Accurate Extraction of Electrically-Small Planar/Non-Planar Microstrip-Line Circuits

This article presents a numerical short-open-load (SOL) calibration technique for accurate extraction of electrically small planar/nonplanar microstrip-line (MSL) circuits and elements in the interface of 3-D full-wave algorithm or simulator. An additional matched-load condition is established at the reference plane and employed in the whole calibration process. In comparison with the traditional short-open calibration (SOC) method, the proposed SOL technique implemented in the interface of software does not inquire prior simulation of the internal current/voltage at the reference plane of two calibration standards but only needs to know the external port impedances of three calibration standards. After the description of entire extraction process, a few typical electrically small planar circuits, such as MSL open-end and step discontinuities, are first numerically deembedded, and their extracted circuit parameters are evidently confirmed with other published ones. Then, a nonplanar structure of a vertically placed shorting pin in the middle of MSL is studied with different sizes and positions to effectively extract the circuit parameters in the two presented equivalent models. Finally, a third-order Chebyshev filter is designed with pin-loaded MSL structures. Its frequency response is synthesized on the proposed SOL method to validate the correctness of the extracted circuit parameters and further demonstrate the usefulness of this method in synthesis design of electrically large microwave circuits. Good agreement among the filtering frequency responses from equivalent circuit model, full-wave simulation, and measurement has well revealed that the proposed SOL method is indeed accurate in numerical extraction of circuit elements and efficient in synthesis design of an entire circuit with prescribed specifications.

Significant Stability Improvement of Fullerene Organic Photovoltaics via ZnO Film Modification through the Intermittent Spray Pyrolysis Technique.

Morphological control of the layers within the bulk heterojunction organic photovoltaics (BHJ-OPVs) is a key feature that governs their performance. In the present work, we demonstrate that zinc oxide—ZnO—interlayers sprayed via the intermittent spray pyrolysis technique, employing a low-concentration precursor solution, can yield inverted BHJ-OPVs as efficient as the standard reported ones using the conventional laboratory-scale spin-coating technique. However, we record a pioneer stability behavior of the fabricated inverted fullerene organic photovoltaics (iF-OPVs) with various sprayed ZnO conditions. Thus, after optimizing the sprayed ZnO interfacial layer morphology for the inverted PTB7-Th:PC70BM devices, by carefully inspecting the interdependence between the sprayed ZnO thin film morphology and the figures of merit of the optimized iF-OPVs, we conducted a distinct analysis on the optical and electronic properties of the fresh and degraded devices using external quantum efficiency measurements and impedance spectroscopy. Hence, we showed that the most proper ZnO microstructural morphology was obtained by spraying 25 running cycles (25R). Remarkably, we observed that 25R-ZnO-based iF-OPV devices showed a stunning stability behavior and maintained 85% of their initial power conversion efficiency even after 16.7 months without encapsulation in a dry nitrogen glovebox, demonstrating an excellent shelf stability. Accordingly, this approach might facilitate the scalability of inverted OPVs for industrial production visibility.

An Energy Harvester Coupled with a Triboelectric Mechanism and Electrostatic Mechanism for Biomechanical Energy Harvesting.

Energy-harvesting devices based on a single energy conversion mechanism generally have a low output and low conversion efficiency. To solve this problem, an energy harvester coupled with a triboelectric mechanism and electrostatic mechanism for biomechanical energy harvesting is presented. The output performances of the device coupled with a triboelectric mechanism and electrostatic mechanism were systematically studied through principle analysis, simulation, and experimental demonstration. Experiments showed that the output performance of the device was greatly improved by coupling the electrostatic induction mechanisms, and a sustainable and enhanced peak power of approximately 289 μW was produced when the external impedance was 100 MΩ, which gave over a 46-fold enhancement to the conventional single triboelectric conversion mechanism. Moreover, it showed higher resolution for motion states compared with the conventional triboelectric nanogenerator, and can precisely and constantly monitor and distinguish various motion states, including stepping, walking, running, and jumping. Furthermore, it can charge a capacitor of 10 μF to 3 V within 2 min and light up 16 LEDs. On this basis, a self-powered access control system, based on gait recognition, was successfully demonstrated. This work proposes a novel and cost-effective method for biomechanical energy harvesting, which provides a more convenient choice for human motion status monitoring and can be widely used in personnel identification systems.

On the Design and Topology Selection of Permanent Magnet Synchronous Generators for Natural Impedance Matching in Small-Scale Uncontrolled Passive Wind Generator Systems

Small-scale uncontrolled passive wind generator systems are an attractive solution for rural energy generation because of the system’s reliability and low cost. However, designing these uncontrolled wind generators for good power matching with the wind turbine is challenging and often requires external impedance matching. In this paper, permanent magnet generators with different stator and rotor structures were investigated and designed to increase the generator’s synchronous inductance for a natural impedance matching. For the design methodology, multi-objective optimisation was used to design the generators for near-maximum turbine power matching, whereby internal impedance matching was reached as much as possible. It was shown that altering the placement and orientation of the permanent magnets in the rotor is a viable method to achieve the desired impedance matching; however, these generators do not have the best performance. It was found that the surface-mounted permanent magnet generator with semi-closed slots was the optimum topology. An optimised generator prototype was tested for the experimental validation. All designs were verified by comparing the results of 2D and 3D finite-element analysis.

Energy Optimization of a Mirror‐Symmetric Spherical Triboelectric Nanogenerator

AbstractA general theoretical analysis of a 3D generic TENG structure is presented. Using a dimensionless formulation, it is demonstrated that the optimal TENG geometry does not depend on the frequency of the moving dielectric but the external ohmic impedance for maximum power output is inversely proportional to the frequency. It is also found that the energy is proportional to the cube of the size of the TENG, the square of the triboelectric charge density σT, and the angular frequency ω of the moving dielectric. In the case of a spherical TENG where the moving dielectric is a sphere and the electrodes are spherical caps on a larger sphere three dimensionless parameters that determine the harvested energy are identified: the ratio between the radii of the two spheres = r/R, the polar angle θ of the two spherical caps formed by the electrodes, and = ZεRω, whereZis the external impedance,Ris the radius of the large sphere, ε is the permittivity of the system, and ω is the angular frequency of the moving sphere. Under the crude assumption of constant charge density on the electrodes, the optimal parameters can be easily calculated. It is found that θ = 1.1 rad, = 0.67, and = 0.18.

Improving robotic impedance control performance employing a cascaded controller based on virtual dynamics model

We propose a cascaded impedance control algorithm based on a virtual dynamics model (VDM) to achieve robust and effective mechanical impedance for a robot interacting with unknown environments. This cascaded controller consists of an internal loop of virtual impedance control based on a VDM and an external loop of impedance reference control. The VDM-based virtual impedance control can achieve the same effect as the conventional admittance control; its intermediate output of force/torque serves as the input for the external loop reference impedance control. Therefore, this cascaded controller shows superior performance by combining the advantages of admittance control and impedance control. We evaluate the controller in multiple-contact experiments on a six-degrees of freedom (6-DOF) industrial robot manipulator. The result shows that under various contact situations such as soft and rigid surfaces and free space, the proposed method can rapidly track the target and effectively maintain stability. In the experiments conducted on the robot in contact with various environments, the proposed control method reduced the steady-state error by more than 20% compared with the conventional admittance control.

Effect of Additives and Annealing on the Performance of Nonfullerene‐Based Binary and Ternary Organic Photovoltaics

Fine tuning of blend morphology is a key factor that limits the performance of the bulk‐heterojunction organic photovoltaics (BHJ‐OPVs). Herein, the morphological control of the binary (PM6:Y7) and ternary (PM6:Y7:PC70BM) blends is conducted through 1‐chloronaphthalene (CN) solvent additive and thermal annealing (TA) treatment with respect to their influence on the photovoltaic performance. Moreover, a distinct study is accomplished on the optical and electronic properties of the treated and nontreated binary and ternary devices by external quantum efficiency measurements and impedance spectroscopy. The results indicate that these treatments affect the performance of the binary and ternary OPVs differently. Regarding the 2% CN addition, the current density of the binary devices is improved by ≈27%, whereas the fill factor of the ternary devices shows a pronounced increment of ≈22%. A contradictory behavior is exhibited by TA for the binary and ternary OPVs. The PCEs for binary devices (with/without CN) and 2% CN‐treated ternary ones are improved, while diminishing the PCEs of the ternary ones with 0% CN. Accordingly, the highest efficiencies of the binary and ternary OPVs are obtained due to the dual effect of 2% CN solvent additive along with the TA treatments.

A unified equivalent circuit and impedance analysis method for galloping piezoelectric energy harvesters

In the past decade, galloping-based energy harvesters (GPEH) connected with various interface circuits have been developed and analytical models have been built. However, the power performances of these advanced structures and circuits are always treated separately, and a general model is missing to gain insights at a system level. To tackle this issue, this paper proposes a unified analysis framework for GPEHs. Its results are consistent with validated (but disconnected) results in the literature. The method provides an integrated view of the physics of linear GPEHs in multiple domains at the system level, and elucidates the similarities and differences among power behaviors of GPEHs connected with various interface circuits. The framework is based on two major elements: an equivalent circuit that represents the entire system, and an equivalent impedance that represents the interface circuit. Firstly, the electromechanical system is linearized and modeled in the electrical domain by an equivalent self-excited circuit with a negative resistive element representing the external aerodynamic excitation, and a general load impedance representing the interface circuit. Then, a closed-form, analytical expression of the harvested power is obtained based on the Kirchhoff’s Voltage Law, from which the optimal load, maximum power, power limit, and critical electromechanical coupling (minimum coupling to reach the power limit) are determined. In this unified analysis, the exact type of energy harvesting interface circuit is not assumed. After that, the power characteristics of a GPEH connected with five representative interface circuits are analytically derived and discussed, by using the particular equivalent impedance of the interface circuit of interest. It is shown that they are subjected to the same power limit. However, the critical electromechanical coupling depends on the type of circuit. Throughout the discussions, impedance plots are used to illustrate the relationship between the internal system characteristics and external load impedance, facilitating the understanding of system power behavior.

Downhole Fluid Analysis During Wellbore Sampling at High Temperatures Using a Pyroelectric Array Spectrometer

While the world is transitioning into a greener and less-carbon-rich energy source, the fact remains that there is a growing need for exploration and production of hydrocarbons in previously untapped resources. These frontier reservoirs, while extremely hot, are prolific and make the footprint of the exploration activity much smaller than shallower drilling, which would require many more wells to deliver the same amount of hydrocarbon. These frontier wells, classified as high-pressure/high-temperature (HP/HT) wells, are defined as wells with reservoir or bottomhole temperatures higher than 300°F and which require pressure-control equipment with a rating above 10,000 psi. HP/HT wells can be found offshore in the North Sea and Gulf of Mexico, or on land—as seen recently in the Gongola Basin. Fluid identification, which is a critical process in fluid sampling, continues to be a challenge in temperatures above 350°F. At temperatures up to 450°F, fluid identification is currently achieved by bubblepoint and compressibility measurements, which cannot quantitatively measure contamination levels of the subject sample fluid. A possible solution to this problem would involve using pyroelectric detectors in the process of estimating a property of a downhole fluid. The method and apparatus in this approach involves exposing a fluid to modulated light downhole and sensing changes in the intensity of infrared radiation from the downhole fluid, to estimate the level of filtrate contamination and other properties. The pyroelectric detector senses changes in the intensity of light by con-verting the transient changes in temperature of its detector and performs the spectroscopic fluid analysis by optically filtering the light allowed to impinge on it, converting the changes in temperature of the pyroelectric detector to a signal which can then be used to estimate the property of the downhole fluid. If successfully implemented, this would enable the wireline-logging industry to develop an optical fluid analyser capable of quantitatively measuring fluid contamination levels in high-temperature (greater than 300°F) environments. Theory Pyroelectric infrared detectors (PIR) convert the changes in incoming infrared light to electric signals. Pyroelectric materials are characterized by having spontaneous electric polarization, which is altered by temperature changes as infrared light illuminates the elements. Pyroelectric detectors (Fig. 1) are thermal detectors, meaning they produce a signal in response to a change in their temperature. Below a case temperature (Tc) known as the Curie point, ferroelectric materials such as lithium tantalate exhibit a large spontaneous electrical polarization. If the temperature of such a material is altered, for example by incident radiation, the polarization changes. This change in polarization may be observed as an electrical signal when electrodes are placed on opposite faces of a thin slice of the material to form a capacitor. When the polarization changes, if the external impedance is comparatively high, the charges induced in the electrodes can be made to produce a voltage across the slice. The sensor will only produce an electrical output signal when the temperature changes; that is, when the level of incident-radiation changes.

Дифференциальная электрохимическая импедансная спектроскопия полимерных протонных электролитов

A method of deriving standard electrochemical impedance spectroscopy (EIS) data such as Bode diagram, Nyquist diagram, and others from frequency dependence of the external impedance using numerical differentiation of the indicated dependence in quadratic coordinates is proposed, the method being named as the differential electrochemical impedance spectroscopy (DEIS). The method was tested experimentally on polyvinyl alcohol-based proton membranes doped with sulphated montmorillonite in granulated or dispersed states as an example. It is shown that DEIS data can be easier and with higher accuracy described by regular semicircles while leaving intact values of ohmic resistance. Very high values of dielectric permeability were obtained in the work enabling to develop condensers with high capacity based on highly conductive polymeric proton electrolytes.

A thermoacoustic combined cooling, heating, and power (CCHP) system for waste heat and LNG cold energy recovery

Waste energy recovery is crucial for reducing greenhouse gas emissions and alleviating the increasing demand for central power grids. In the paper, theoretical analyses have been carried out on a novel thermoacoustic combined cooling, heating, and power system for simultaneously recovering waste heat and liquefied natural gas cold energy. The system is designed based on acoustic impedance matching between the thermoacoustic and alternator units for maximizing the overall exergy efficiency. The efficiency, cost savings, and emission reductions of the optimal system are investigated. With cold and waste heat temperatures of 130 K and 500 K, the system achieves an overall exergy efficiency of 24.1%, allowing 78.4 MWh of primary fuel energy reduction, and correspondingly, 30.6 tons of CO2 emissions reduction per year. Investigations are further performed on the system parametric sensitivities. A method for adjusting the alternator external electric impedance is proposed to allow for matching piston displacement within design parameters. Besides, comparisons are made with alternative thermoacoustic cogeneration models. The results show that the proposed system can operate effectively for various supply modes, which is promising for adaptation in different applications. Finally, comparisons are drawn with similar existing technologies and future developments are discussed.

Revealing the Degradation and Self-Healing Mechanisms in Perovskite Solar Cells by Sub-Bandgap External Quantum Efficiency Spectroscopy.

Ion dissociation has been identified to determine the intrinsic stability of perovskite solar cells (PVSCs), but the underlying degradation mechanism is still elusive. Herein, by combining highly sensitive sub-bandgap external quantum efficiency (s-EQE) spectroscopy, impedance analysis, and theoretical calculations, the evolution of defect states in PVSCs during the degradation can be monitored. It is found that the degradation of PVSCs can be divided into three steps: 1) dissociation of ions from perovskite lattices, 2) migration of dissociated ions, and 3) consumption of I- by reacting with metal electrode. Importantly, step (3) is found to be crucial as it will accelerate the first two steps and lead to continuous degradation. By replacing the metal with more chemically robust indium tin oxide (ITO), it is found that the dissociated ions under light soaking will only saturate at the perovskite/ITO interface. Importantly, the dissociated ions will subsequently restore to the corresponding vacancies under dark condition to heal the perovskite and photovoltaic performance. Such shuttling of mobile ions without consumption in the ITO-contact PVSCs results in harvesting-rest-recovery cycles in natural day/night operation. It is envisioned that the mechanism of the intrinsic perovskite material degradation reported here will lead to clearer research directions toward highly stable PVSCs.

Signal Transmission Capability Improvement of a Telemetry Drill String Using the Reflected Signal at the Transmission Line Termination

A telemetry drill string system consists of a string of wired drill pipes, and high-frequency signals pass the adjacent drill pipes through inductive couplers. Such a system is used to upload downhole information at high data transmission rates for measurements while drilling (MWD). Since the signal energy attenuates greatly in the system, many repeaters must be provided to ensure signal transmission. A reduction in the signal transmission in a telemetry drill string can extend the relay distance and improve the reliability of the transmission system. In this study, the transmission characteristic of the rod of the wired drill pipe is studied using transmission line theory, and the transmission characteristic of the inductive coupler is studied using high-frequency circuit theory. Using impedance matching between the transmission line of the rod and the inductive coupler, external impedance compensation elements, including a capacitor and a resistor, are recommended, and the electromagnetic parameters of the wired drill pipe are determined. Based on the determined electromagnetic parameters, certain changes in the external impedance compensation capacitance and resistance can lead to impedance mismatch between the transmission line and the inductive coupler. This will generate a reflected signal at the transmission line, and the vector superposes with the transmitted signal. The terminal reflection coefficient of the transmission line is controlled by increasing the compensation resistance value to enhance the signal amplitude, which can compensate the transmission loss when passing through the inductive coupler to a certain extent. Thus, the signal transmission capability of the telemetry drill string can be improved, allowing for long-distance signal transmission or drastically extending the relay distance, while maintaining a certain channel bandwidth.

Diagnosis and Analysis of Load Current Divergence in Z-Pinch Experiments

During the later stage of stagnation in Z-pinch experiments, a current divergence phenomenon often occurs that downstream current (load current measured in a vacuum) declines slowly to zero, while upstream current (current measured outside vacuum) normally decays with quasi-sinusoidal oscillation. To investigate the formation mechanism of this current divergence, the possible abnormal discharge channels in vacuum are captured by optical imaging in this article. Both time integral image and time-resolved image show that current divergence is accompanied by the surface flashover on the vacuum insulator. The time-resolved images also verified that the time when downstream current starts slow decline corresponds to the time when surface flashover occurs. Surface flashover changes the circuit topology and forms the freewheeling branch of the load inductance L. An equivalent circuit is also established to analyze the current divergence. The discharge channel with low resistance R results in large time constant (L/R) and makes the downstream current drop slowly, while the external impedance can make the upstream current keep the waveform of oscillation attenuation even under the condition of internal flashover. Moreover, the influence caused by current divergence is discussed in the aspect of load voltage and the energy dissipation on generator. According to the simulation results, with an appropriate resistance, an additional branch can help protect the upstream components.

Impedance Modeling and Controllers Shaping Effect Analysis of PMSG Wind Turbines

Oscillation issues of permanent magnet synchronous generator (PMSG) wind turbines (WTs) have an increasingly significant impact on grid stability, especially with their increased generation capacity. However, the machine-side model (MSM), involving machine-side converter (MSC) and generator, is generally simplified as an ideal voltage source to comprising the impedance model of a PMSG-WT used for stability analysis, thus causing deficiency in describing the machine dynamics. Besides, the impedance-based method considering the PMSG-WT as a black box only describes the system from the external output characteristics; as such, the shaping effect of the internal controllers on the impedance model has not been fully studied yet. This article proposes the impedance model of PMSG-WTs consisting of generator, MSC, dc-bus and grid-side converter (GSC) for more accurate stability analysis. Furthermore, based on the general Nyquist criteria (GNC) and eigenvalue sensitivity analysis method, the shaping effect of the controllers inside GSC and MSC on the PMSG external impedance is quantitatively studied. The influence of the MSM on the system stability is investigated by comparing with the simplified model through extensive simulation studies.

Cooperative Manipulation of an Unknown Object via Omnidirectional Unmanned Aerial Vehicles

This paper addresses the problem of cooperative manipulation and transportation of large and/or heavy unknown objects via a team of aerial robots. In particular, the chosen aerial platform is an omnidirectional quadrotor, which, by exploiting two additional actuators, has the capability to produce an omnidirectional total thrust by changing the orientation of the plane of the rotors. Since it is assumed that the object geometry and dynamic parameters are not known, the devised strategy includes a first stage in which the robots cooperatively estimate the object parameters and a second stage in which such parameters are adopted in an impedance control, aimed at limiting both the contact wrenches, due to the object/environment interaction, and the internal wrenches, due to the robot/object interaction. More in detail, two admittance filters are designed to determine the reference trajectory for the object (external impedance) and for the aerial vehicles (internal impedance). Finally, a simulation case study is developed to provide further insights on the proposed approach.