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Full-Text Articles in Engineering
Characteristic Mode Analysis Prediction And Guidance Of Electromagnetic Coupling Measurements To A Uav Model, Mohamed Z. M. Hamdalla, Benjamin Bissen, James D. Hunter, Yuanzhuo Liu, Victor Khilkevich, Daryl G. Beetner, Anthony N. Caruso, Ahmed M. Hassan
Characteristic Mode Analysis Prediction And Guidance Of Electromagnetic Coupling Measurements To A Uav Model, Mohamed Z. M. Hamdalla, Benjamin Bissen, James D. Hunter, Yuanzhuo Liu, Victor Khilkevich, Daryl G. Beetner, Anthony N. Caruso, Ahmed M. Hassan
Electrical and Computer Engineering Faculty Research & Creative Works
In this work, we study the current coupled to a simplified Unmanned Aerial Vehicle (UAV) model using a dual computational and experimental approach. The simplified surrogate structure reduced the computational burden and facilitated the experimental measurement of the coupled currents. For a practical system, a wide range of simulations and measurements must be performed to analyze the induced current variations with respect to properties of the incident excitation waveform, such as the frequency, angle of incidence, and polarization. To simplify this analysis, Characteristic Mode Analysis (CMA) was used to compute the eigen-currents of the UAV model and predict where and …
Cavities' Identification Algorithm For Power Integrity Analysis Of Complex Boards, S. Cicerone, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor, Jun Fan, James L. Drewniak
Cavities' Identification Algorithm For Power Integrity Analysis Of Complex Boards, S. Cicerone, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor, Jun Fan, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
The analysis and the design of the Power Delivery Network (PDN) is crucial in the real world of high-speed and high-performance on-board systems. In this context, the Cavity Model (where facing portions of power bus are considered electromagnetic resonant cavities) can be used to study the generation and propagation of noise. Given a real-world board's layout, one of the primary requirements for the application of this technique is the geometrical identification of all the cavities and their connectivity. This paper is focused on the fully automatic generation of this geometrical dataset as part of an integrated tool for the analysis …
Automated Near-Field Scanning To Identify Resonances, Giorgi Muchaidze, Huang Wei, Jin Min, Shao Peng, James L. Drewniak, David Pommerenke
Automated Near-Field Scanning To Identify Resonances, Giorgi Muchaidze, Huang Wei, Jin Min, Shao Peng, James L. Drewniak, David Pommerenke
Electrical and Computer Engineering Faculty Research & Creative Works
Near-field scanning systems are a tool for rootcause ESD, EMI, and immunity analysis of electronic systems, as well as qualification methodology for ICs and modules. For emissions, they have developed into a standardized method. Development of universally accepted file formats for data exchange is on-going. Four main types of scanning have been implemented by this and other authors: Near-field EMI scanning, ESD scanning, radiated immunity scanning, and resonance scanning. This article concentrates on resonance scanning as a newly added method for automated EMC system analysis.
Orthogonal Loops Probe Design And Characterization For Near-Field Measurement, Tun Li, Yong Cheh Ho, David Pommerenke
Orthogonal Loops Probe Design And Characterization For Near-Field Measurement, Tun Li, Yong Cheh Ho, David Pommerenke
Electrical and Computer Engineering Faculty Research & Creative Works
Near-field probes are often used to measure the electric and magnetic fields above a printed circuit board in order to identify the sources and coupling paths of an electromagnetic interference (EMI) problem. It is the objective of this paper to propose a rapid E-, Hx- Hy- and circular H-fields measurement using an orthogonal loops probe design. The effects of this probe are analyzed using full-wave simulations and measurements.
Estimating Maximum Radiated Emissions From Printed Circuit Boards With An Attached Cable, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner
Estimating Maximum Radiated Emissions From Printed Circuit Boards With An Attached Cable, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner
Electrical and Computer Engineering Faculty Research & Creative Works
The common-mode current induced on cables attached to printed circuit boards can be a significant source of radiated emissions. Previous studies have shown that coupling from electric and magnetic field sources on circuit boards can be effectively modeled by placing equivalent voltage sources between the board and the cable. The amplitude of these equivalent sources can be estimated by using closed-form equations; however, estimates of the radiated emissions from these board-cable geometries have required full-wave simulations, and full-wave simulation results depend on the exact cable length and placement, which are not normally fixed during radiated emissions testing. This paper develops …
Predictive Modeling Of The Effects Of Skew And Imbalance On Radiated Emi From Cables, J. Chen, James L. Drewniak, Richard E. Dubroff, James L. Knighten, Jun Fan, J. Flavin
Predictive Modeling Of The Effects Of Skew And Imbalance On Radiated Emi From Cables, J. Chen, James L. Drewniak, Richard E. Dubroff, James L. Knighten, Jun Fan, J. Flavin
Electrical and Computer Engineering Faculty Research & Creative Works
This paper provides an approach for predicting the effects of skew and imbalance on radiated emission of cables inside a commercial 19-inch rack-based cabinet. Scattering parameters (S-parameters) for two sets of cable assembly are measured with a four-port vector network analyzer (VNA) and converted into mixed mode S-parameters. Time-domain input signals with different slew rates and different amount of skew are transferred into frequency-domain using fast Fourier transform (FFT). The spectra of radiation emission associated with different inputs are then estimated.
Engineering Of Absorbing Gaskets Between Metal Plates, Marina Koledintseva, Sandeep K. R. Chandra, James L. Drewniak, James A. Lenn
Engineering Of Absorbing Gaskets Between Metal Plates, Marina Koledintseva, Sandeep K. R. Chandra, James L. Drewniak, James A. Lenn
Electrical and Computer Engineering Faculty Research & Creative Works
Engineering of absorbing materials for gaskets that would be used between two metal plates to reduce electromagnetic emissions and improve immunity of electronic equipment is considered. An analytical model of a composite based on the Maxwell Garnett formulation for multiphase mixtures, as well as the shielding effectiveness of this material, are presented. The full-wave numerical computational results for the structure consisting of two overlapping metal plates and an engineered gasket composite material in the place of the overlap are presented.
Common-Mode Radiation Resulting From Hand-Assembled Cable Bundles On Automotive Platforms, Shishuang Sun, James L. Drewniak, David Pommerenke
Common-Mode Radiation Resulting From Hand-Assembled Cable Bundles On Automotive Platforms, Shishuang Sun, James L. Drewniak, David Pommerenke
Electrical and Computer Engineering Faculty Research & Creative Works
A statistical cable harness model is developed to account for the random disturbance of the wire positions along hand-assembled bundles. The non-uniform random bundles are modeled as n-cascaded segments of uniform multi-conductor transmission line. At each section, all wire positions are disturbed with random numbers obeying a Gaussian distribution. In addition, a spline interpolation function is used to improve the smoothness of wires winding along the bundle. The common-mode current distribution along the bundle calculated with SPICE is injected into a full-wave tool, e.g., FDTD, as impressed current sources. Thus, the full-vehicle electromagnetic emissions from the automotive harness can …
Estimation Of Current From Near-Field Measurement, Haixiao Weng, Daryl G. Beetner, Richard E. Dubroff, Jin Shi
Estimation Of Current From Near-Field Measurement, Haixiao Weng, Daryl G. Beetner, Richard E. Dubroff, Jin Shi
Electrical and Computer Engineering Faculty Research & Creative Works
Knowledge of high-frequency currents in the chip and chip-package are necessary for EMI analysis and prediction, though measurement of these currents may be difficult to obtain in many cases. One possibility is to estimate currents from near-field scan data. In this paper, measurements were made of the magnetic field over a simple circuit and a chip package. The current flowing in the circuit and the chip lead frame was estimated from the compensated near-field data and compared with measurements made directly on the pins. Estimation was performed both with and without structural information of the lead frame. The susceptibility of …
Coupling Between Differential Signals And The Dc Power-Bus In Multilayer Pcbs, Chen Wang, Marco Leone, James L. Drewniak, Antonio Orlandi
Coupling Between Differential Signals And The Dc Power-Bus In Multilayer Pcbs, Chen Wang, Marco Leone, James L. Drewniak, Antonio Orlandi
Electrical and Computer Engineering Faculty Research & Creative Works
Differential and common-mode transfer impedances are proposed herein to analyze noise coupled to (from) the dc power-bus from (to) via transitions in differential signals. Expressions for the two transfer impedances in terms of conventional single-ended transfer impedances are derived and verified through measurements, full-wave finite-difference time-domain (FDTD) simulations and an analytical cavity model. Some properties of the differential and common-mode transfer impedances are investigated to facilitate engineering design. The impact of signal current imbalances on power-bus noise and the benefit of differential signals as compared to single-ended signals are quantified.
Emi Specifics Of Synchronous Dc-Dc Buck Converters, Zhe Li, David Pommerenke
Emi Specifics Of Synchronous Dc-Dc Buck Converters, Zhe Li, David Pommerenke
Electrical and Computer Engineering Faculty Research & Creative Works
DC-DC buck converter topology is widely used in computers and telecom applications because of its high power efficiency and multiple DC levels. However, EMI can be an issue because of its fast switching characteristics and large currents. This paper addresses the analysis of radiated EMI problems associated with DC-DC buck converters and evaluates the effectiveness of solutions that minimize the reverse recovery of the drain-bulk diode of the synchronous switching MOSFET.
Analytical Model For The Rectangular Power-Ground Structure Including Radiation Loss, Ji Chen, Todd H. Hubing, Weimin Shi, R. L. Chen
Analytical Model For The Rectangular Power-Ground Structure Including Radiation Loss, Ji Chen, Todd H. Hubing, Weimin Shi, R. L. Chen
Electrical and Computer Engineering Faculty Research & Creative Works
An accurate analytical model to predict via coupling within rectangular power-return plane structures is developed. Loss mechanisms, including radiation loss, dielectric loss, and conductor loss, are considered in this model. The radiation loss is incorporated into a complex propagating wavenumber as an artificial loss mechanism. The quality factors associated with three loss mechanisms are calculated and compared. The effects of radiation loss on input impedances and reflection coefficients are investigated for both high-dielectric-loss and low-dielectric-loss printed circuit boards. Measurements are performed to validate the effectiveness of this model.
Calibration And Compensation Of Near-Field Scan Measurements, Masahiro Yamaguchi, Richard E. Dubroff, Kevin P. Slattery, Michael A. Cracraft, Jin Shi
Calibration And Compensation Of Near-Field Scan Measurements, Masahiro Yamaguchi, Richard E. Dubroff, Kevin P. Slattery, Michael A. Cracraft, Jin Shi
Electrical and Computer Engineering Faculty Research & Creative Works
A procedure for the calibration and compensation of near-field scanning is described and demonstrated. Ultimately, the objective is to quantify the individual field components associated with electromagnetic interference (EMI) from high speed circuitry and devices. Specific examples of these methods are shown. The effects of compensation are small but noticeable when the uncompensated output signal from near field scanning is already a very good representation of the field being measured. In other cases, the improvement provided by compensation can be significant when the uncompensated output signal bears little resemblance to the underlying field.
A Study On The Correspondence Of Common-Mode Current In Electromagnetic Radiation From A Pcb With A Guard-Band, Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue, James L. Drewniak
A Study On The Correspondence Of Common-Mode Current In Electromagnetic Radiation From A Pcb With A Guard-Band, Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
A PCB, in which the ground plane has a finite width and the trace has unbalanced positioning, can result in common-mode (CM) radiation. So far, CM current which is generated by the unbalance of a trace and ground plane has been investigated by experiment and numerical method. It was clarified that CM current is well explained the radiation from PCB up to a few hundred megahertz, and addition of a guard band geometry, which is well connected to the ground plane, can be effective in suppressing the CM current. But it is seemed to be insufficient description for the phenomena …
Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Electrical and Computer Engineering Faculty Research & Creative Works
A dual-step MTL / FDTD strategy is proposed for anticipating full-vehicle level EMI. In the first step, the current distribution along a cable bundle connecting to electronic modules an an automotive platform is calculated using multi-conductor transmission-line (MTL) models. In order to account for common-mode discontinuities on the vehicle chassis, e.g., slots, 3D full-wave modeling (FDTD) is used to determine radiation impedances, which are thereafter incorporated in the MTL models for compensating the radiation power loss. In the second step, the obtained currents are implemented as impressed current sources in full-vehicle full-wave modeling using an FDTD multi-wire subcelluar algorithm. Thus, …
Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi
Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi
Electrical and Computer Engineering Faculty Research & Creative Works
Digital devices and discontinuities are typically analyzed by inserting their equivalent circuits into SPICE-type simulators. The partial element equivalent circuit method has been proven to be very useful for electromagnetic modeling. It can be used in both the time and the frequency domain. In this paper, the PEEC technique is employed as an efficient full-wave modeling tool to derive SPICE-type equivalent circuits of signal via transition structures. A nodal analysis technique is utilized in conjunction with the optimization algorithm to extract the equivalent circuits, whose component values are the parameters optimized. The good agreement between different approaches demonstrates that the …
Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires
Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires
Electrical and Computer Engineering Faculty Research & Creative Works
Radiated emission algorithms for a printed circuit board EMC expert system are described. The expert system mimics the thinking processes that human EMC engineers would use to analyze circuit boards and make design recommendations. Working with limited information about the enclosure, cables or the exact nature of the signals, the expert system evaluates different structures on the printed circuit board looking for potentially strong radiated emission sources. Results obtained from the analysis of a sample printed circuit board are provided to demonstrate how the expert system quickly identifies problems that would otherwise be difficult to locate.
Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant
Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant
Electrical and Computer Engineering Faculty Research & Creative Works
Most existing power supplies for induction heating equipment produce voltage at a single (adjustable) frequency. Recently, however, induction heating power supplies that produce voltage at two (adjustable) frequencies have been researched and even commercialized. Dual-frequency power supplies are a significant development for heat-treating workpieces with uneven geometries, such as gears, since different portions of such workpieces are heated dissimilarly at a single frequency and so require a two step process using a single-frequency power supply. On the other hand, a dual-frequency power supply can achieve the desired result for such workpieces in a one step process. This paper proposes the …
Electromagnetic Interference (Emi) Of System-On-Package (Sop), Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak
Electromagnetic Interference (Emi) Of System-On-Package (Sop), Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …
Using Near-Field Scanning To Predict Radiated Fields, Jin Shi, Michael A. Cracraft, Jianmin Zhang, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi
Using Near-Field Scanning To Predict Radiated Fields, Jin Shi, Michael A. Cracraft, Jianmin Zhang, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi
Electrical and Computer Engineering Faculty Research & Creative Works
Near-field scanning has often been used to measure and characterize magnetic fields surrounding individual integrated circuits (IC) and high speed digital electronic circuits. The paper describes the use of near-field scanning data, performed in a typical laboratory bench top environment, to predict radiated electromagnetic interference (EMI) in a typical product environment. The product environment may include enclosures and apertures. The approach begins by acquiring sufficient near-field scanning data to allow representation of an unintentional radiating source by an equivalent surface current distribution. The equivalent current distribution is used as a source in numerical full wave modeling. The agreement between direct …
Via Coupling Within Power-Return Plane Structures Considering The Radiation Loss, J. Chen, Todd H. Hubing, Weimin Shi, R. L. Chen
Via Coupling Within Power-Return Plane Structures Considering The Radiation Loss, J. Chen, Todd H. Hubing, Weimin Shi, R. L. Chen
Electrical and Computer Engineering Faculty Research & Creative Works
An accurate analytical model to predict via coupling within rectangular power-return plane structures is developed. Loss mechanisms, including radiation loss, dielectric loss, and conductor loss, are considered. The radiation loss is incorporated into a complex propagating wavenumber as an artificial loss mechanism. The quality factors associated with the three loss mechanisms are calculated and compared. The effects of radiation loss on input impedances and reflection coefficients are investigated for both high-dielectric-loss and low-dielectric-loss PCBs. Measurements are performed to validate the effectiveness of the model.
Analysis Of Chip-Level Emi Using Near-Field Magnetic Scanning, Xiaopeng Dong, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner
Analysis Of Chip-Level Emi Using Near-Field Magnetic Scanning, Xiaopeng Dong, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner
Electrical and Computer Engineering Faculty Research & Creative Works
Integrated circuits (ICs) are often a significant source of radiated energy from electronic systems. Well designed ICs maintain good control of the currents that they generate. However, poorly designed ICs can drive high-frequency noise currents onto nominally low-frequency input and output pins. These currents can excite unintentional radiating structures on the printed circuit board, resulting in radiated emissions that are difficult or expensive to control. The paper discusses the use of magnetic near-field scanning techniques to measure the current distribution in IC packages. This technique is applied to common ICs, including a clock driver, a memory module and a field …
Spectrum Visualization And Measurement Of Power Parameters Of Microwave Wide-Band Noise, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin, V. Radchenko
Spectrum Visualization And Measurement Of Power Parameters Of Microwave Wide-Band Noise, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin, V. Radchenko
Electrical and Computer Engineering Faculty Research & Creative Works
A method for an adequate visualization of a microwave intense noise spectrum envelope in a wide frequency range (several octaves), measurement of its power parameters, and detection of a narrow-band signal with unknown frequency and power against the noise background is presented. This method is based on an application of a nonheterodyne principle of microwave frequency (and power) conversion using a gyromagnetic converter, which operates in two regimes in turn: the resonance detection and the cross-multiplication. A block scheme and an operation of a two-channel measuring device combining the mentioned functions are discussed.
Radiated Emissions From Populated Printed Circuit Boards Due To Power Bus Noise, Hwan-Woo Shim, Todd H. Hubing, Yan Fu
Radiated Emissions From Populated Printed Circuit Boards Due To Power Bus Noise, Hwan-Woo Shim, Todd H. Hubing, Yan Fu
Electrical and Computer Engineering Faculty Research & Creative Works
Previous studies have demonstrated that power plane pairs in a printed circuit board are capable of generating significant radiated emissions at resonance frequencies if these resonances are not damped by material or component losses. The paper shows that board resonances may be readily damped by component losses. However, radiated emissions from a damped power bus may still exceed FCC or CISPR limits over a broad band of frequencies.
Statistical Approach To The Emi Modeling Of Large Asics By A Single Noise-Current Source, Giulio Antonini, James L. Drewniak, Marco Leone, Antonio Orlandi, Vittorio Ricchiuti
Statistical Approach To The Emi Modeling Of Large Asics By A Single Noise-Current Source, Giulio Antonini, James L. Drewniak, Marco Leone, Antonio Orlandi, Vittorio Ricchiuti
Electrical and Computer Engineering Faculty Research & Creative Works
Large and complex ASICs are source of propagating noise inside the powerbus planes. A lumped noise source model is proposed and validated by means of a statistics based method.
Electromagnetic Compatibility Issues In Mobile Computing, Antonio Orlandi, James L. Drewniak
Electromagnetic Compatibility Issues In Mobile Computing, Antonio Orlandi, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
No abstract provided.
Anticipating Emi Using Transfer Functions And Signal Integrity Information, Chen Wang, James L. Drewniak, Jim Nadolny
Anticipating Emi Using Transfer Functions And Signal Integrity Information, Chen Wang, James L. Drewniak, Jim Nadolny
Electrical and Computer Engineering Faculty Research & Creative Works
Discontinuities in a circuit can lead to signal integrity as well as EMI problems. A method, which efficiently combines full-wave tools and circuit simulators, is proposed herein to analyze the coupling at discontinuities. The proposed method may be applied to practical engineering designs.
Anticipating Vehicle-Level Emi Using A Multi-Step Approach, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Anticipating Vehicle-Level Emi Using A Multi-Step Approach, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen
Electrical and Computer Engineering Faculty Research & Creative Works
A multi-step procedure for anticipating vehicle-level EMI is proposed in this paper. This approach uses multi-conductor transmission line (MTL) modeling to calculate current distributions along the cable bundle. A common-mode circuit is extracted from the MTL modeling, and is employed in full-vehicle full-wave modeling to determine radiation and interference. In this paper, mode-dispersion and mode-conversion phenomena are investigated, and the ambiguous definitions of the common-mode voltage and common-mode impedance are discussed.
Quantifying The Effects On Emi And Si Of Source Imbalances In Differential Signaling, Chen Wang, James L. Drewniak
Quantifying The Effects On Emi And Si Of Source Imbalances In Differential Signaling, Chen Wang, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
Imbalances in differential signaling can introduce common-mode components, resulting in signal integrity (SI) problems as well as EMI problems. Three-port mixed-mode S-parameters are employed to quantify the impacts on EMI. The EMI problems caused by delay skew and slew rate skew are investigated.
Modeling Issues For Full-Wave Numerical Emi Simulation, Michael A. Cracraft, Xiaoning Ye, Chen Wang, Sandeep K. R. Chandra, James L. Drewniak
Modeling Issues For Full-Wave Numerical Emi Simulation, Michael A. Cracraft, Xiaoning Ye, Chen Wang, Sandeep K. R. Chandra, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
In electromagnetic modeling, agreement between modeling and measurements is a common goal. There are questions that define every model. What is to be modeled? How is it going to be modeled? At what scale is it to be modeled? Through sample results and discussion, this paper addresses some general and some specific elements of model veracity. Through determination, numerical models can certainly be pushed to match any measured results. However, in the end the question that this paper addresses is not necessarily "How good can this model be?" as it is "Is this model good enough?".