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A brief overview of R. Buckminster Fuller's world maps is presented. Exact transformation equations for Fuller's icosahedron-based world map are derived. These equations are differentiable and therefore suitable for standard area distortion analysis. Such distortion analysis has been carried out, and the results are compared to the familiar gnomonic projection onto an icosahedron. In addition to the exact forward unit sphere to XY-plane transformation equations, a relation in one parameter, which must be satisfied by the inverse transformation, is given. Les equations de transformation exacte pour la carte du monde de Fuller On presente un bref survol des cartes du monde de R. Buckminster Fuller. On derive ensuite les equations de transformation exacte pour la carte du monde de Fuller basee sur un icosaedre. Ces equations sont differentielles et conviennent donc a l'analyse normale de distortion des aires. Une telle analyse a ete effectuee et l'on compare les resultats a la projection gnomonique familiere...

Purpose: Gamma Knife (GK) planning is mostly based upon MRI. Due to the high accuracy required for SRS treatments, geometric distortions in these images should be minimal. MRI Manufacturer provided first order geometric distortions correction algorithms may not reduce distortions to a level that may not be acceptable for treatments requiring high positional accuracy. The purpose of this work is to evaluate the residual, radiosurgery-relevant geometric distortions on VIBE, MPRAGE, GRE and CISS sequences. Methods: The 3D rectilinear phantom, GRID3D, was scanned in the Leksell Frame-G with different MRI axial sequences: MPRAGE, VIBE, GRE and CISS, on a Siemens SKYRA 3T MR unit. Siemens 3D distortion correction was applied to all sequences. The residual distortion map of the phantom's 2002 vertices was evaluated by comparing the expected positions of the vertices, with the actual measured locations using Modus’ image distortion analysis software (QUASARTM). Distortions were specified as X, Y, Z, and radial deviations. As an independent verification, the MRI sequences were co-registered with CT images of the phantom in GammaPlan. Results: All sequences showed mean radial residual distortions greater than 1 mm. Maximum radial distortion ranged between 3 and 8 mm. Z axis distortions were the highest for GRE and CISS sequences, and lowest for VIBE. Y distortions were lowest for the VIBE and MPRAGE sequences. X distortion was lowest for GRE and CISS sequences. Almost equal X and Y distortions were measured for CISS. Larger distortions were mainly observed in peripheral regions of the phantom for all sequences. CT-MR co-registration in GammaPlan confirmed these results. The residual distortions were deemed unacceptable for MR based GK treatments. Conclusion: The in-phantom analysis of MR sequences using the Modus phantom allows for effective quantitative evaluation of residual distortion in MR images. MR-CT co-registration facilitates qualitative assessment of MRI distortions.

This paper discusses the bulk FFT technique for multi-carrier demodulators proposed by Campanella and Sayegh (1988). A heuristic analysis of the distortion associated with this method is presented. A modification to the method is proposed using a different overlap/save strategy, and simulation results showing a significant improvement in performance are presented. An analysis of the distortion is given.

Laser differential confocal microscopy (DCM) is widely applied to many fields as an important analysis and measurement approach for its high-resolution imaging capability and unique section imaging capability. Differential confocal microscopy needs a scanning system to achieve the imaging due to its zero-field imaging property. So twodimension vibrating mirror scanning system with fast-speed positioning and high response frequency is wildly used for fast speed scanning system. . However, the two-dimension vibrating mirror scanning system may bring the distortion to the image. Therefore, a mathematic model of the distortion for two-dimension vibrating mirror scanning system is built in this paper. And an inverse function method for correction is put forward and the corresponding theory simulation has been done using MatLab. The proposed method can be operated easily and understood easily, and can be applied to large-scale calculation correction, which can provide an effective way to correct the distortion of two-dimension vibrating mirror scanning system.

Navigation, radar and communication systems rely on radio signals. Objects in the vicinity of these systems can create distortions. This paper outlines the advanced computer system simulation by the integrated scattering analysis with the aid of numerical methods and the adapted system signal processing. Some practical cases are outlined.

Two genetic linkage maps of cultivated maize inbred lines and teosinte species were constructed. One population comprised 81 F(2) individuals derived from a cross between maize inbred line B73 and Zea mays ssp parviglumis, while the second consisted of 63 backcross individuals from a cross of maize inbred line B73 with Z. mays ssp diploperennis. In the B73 x Z. mays ssp parviglumis F(2) population, 172 simple sequence repeat (SSR) markers were mapped to 10 chromosomes, which covered 2210.8 cM. In the B73 x Z. mays ssp diploperennis backcross population, 258 SSR markers were mapped to 10 chromosomes, covering 1357.7 cM. Comparison of the two maps revealed that the total map length of Z. mays ssp diploperennis covers 1357.7 cM, which is about 61.4% of that of Z. mays ssp parviglumis (2210.8 cM). Extensive segregation distortion regions were found on chromosomes 1, 2, 3, 5, 6, 7, and 10 in the B73 x Z. mays ssp parviglumis F(2) population and on chromosomes 1-5 and 8-10 in the B73 x Z. mays ssp parviglumis backcross population. Segregation distortion analysis confirmed that the segregation distortion ratio in the interspecific population B73 x Z. mays ssp diploperennis was higher than in B73 x Z. mays ssp parviglumis. We found that the recombination distances are highly variable in these genetic crosses between cultivated and wild species of maize.

Following the measurement of the rotational spectrum of propene in the microwave and millimeterwave regions, internal rotation and centrifugal distortion analysis is performed. A scaled quantum mechanical force field is calculated, and the theoretical centrifugal distortion constants, calculated from this force field, are compared to the experimental ones.

The Volterra series method of distortion analysis is presented in the analysis of a common emitter circuit. There are presented the model of the integrated circuit and evaluated their non-linearity’s.According to the provided equivalent diagram and using the method of Volterra series, kernels of the respective linear, square and cube system have been figured out. Changes in an operation mode ofa IT within a frequency range influenced by an input signal have been defined taking into account IT parameters and outer elements.

Dissection of stereoelectronic effects in the transition states (TSs) for noncatalyzed azide-alkyne cycloadditions suggests two approaches to selective transition state stabilization in this reaction. First, the formation of both 1,4- and 1,5-isomers is facilitated via hyperconjugative assistance to alkyne bending and C···N bond formation provided by antiperiplanar σ-acceptors at the propargylic carbons. In addition, the 1,5-TS can be stabilized via attractive C-H···F interactions. Although the two effects cannot stabilize the same transition state for the cycloaddition to α,α-difluorocyclooctyne (DIFO), they can act in a complementary, rather than competing, fashion in acyclic alkynes where B3LYP calculations predict up to ∼1 million-fold rate increase relative to 2-butyne. This analysis of stereoelectronic effects is complemented by the distortion analysis, which provides another clear evidence of selective TS stabilization. Changes in electrostatic potential along the reaction path revealed that azide polarization may create unfavorable electrostatic interactions (i.e., for the 1,5-regioisomer formation from 1-fluoro-2-butyne and methyl azide). This observation suggests that more reactive azides can be designed via manipulation of charge distribution in the azide moiety. Combination of these effects with the other activation strategies should lead to the rational design of robust acyclic and cyclic alkyne reagents for fast and tunable "click chemistry". Further computational and experimental studies confirmed the generality of the above accelerating effects and compared them with the conjugative TS stabilization by π-acceptors.

Image distortion analysis is a fundamental issue in many image processing problems, including compression, restoration, recognition, classification, and retrieval. In this work, we investigate the problem of image distortion measurement based on the theories of Kolmogorov complexity and normalized information distance (NID), which have rarely been studied in the context of image processing. Based on a wavelet domain Gaussian scale mixture model of images, we approximate NID using a Shannon entropy based method. This leads to a series of novel distortion measures that are competitive with state‐of‐the‐art image quality assessment approaches.

The ground state rotational spectrum of CHF2Cl has been observed and analyzed in the frequency region 70-1280 GHz. Transitions with values of J up to 80 have been observed and the centrifugal distortion analysis of the spectrum has been performed using both the A- and the S-reduced forms of Watson′s Hamiltonian. Accurate values of the quartic and sextic centrifugal distortion constants have been obtained.

Using cryo-microscopy at liquid-helium temperature we have determined the projection structure of the surface layer of the archaebacterium Sulfolobus shibatae embedded in aurothioglucose to a resolution of 0.85 nm. Image analysis was performed in real space and incorporated a classification of unit cells, thus taking into account the frequent occurrence of twin boundaries. In an attempt to identify resolution-limiting factors we have performed a distortion analysis quantifying the main distortion parameters.

The rotational spectrum of methylenecyclopropene has been measured in the 180–650 GHz frequency range. One hundred and forty-three new lines have been assigned and a centrifugal distortion analysis is presented. The experimental values of the centrifugal distortion constants confirm the rigidity of this molecule related to the high ring strain.

This paper continues to build the gray system model to analyze building deformation, based on the analysis of traditional model of gray system theory, making comparison between the original observation data series and the predicted progression which are concluded by the built model, then to put the residuals into system. Facts have proved that to use the residual gray combination model in building distortion analysis is a convenient and reliable method of deformation analysis, which can effectively improve the model's accuracy and obtain good prediction results.

Analyze the operating principle of segment, calculate the radial pressure on the hot rolling coiler mandrel. Simulate working condition of segment based on finite element software, make distortion analysis and stress analysis, optimize the design of segment structure, combining the distribution situation of cracks, so as to effectively improve the stress concentration problem. The application of new structure is quite effective, and the generation and extension of crack can be well controlled.

The design of orienting rotary steerable drilling tools needs to take both the location of the floating support points and flexural distortion of the mandrel into account. With consideration of the eccentric displacement and bias of offset components in such a biasing apparatus, a comprehensive mechanical model has been proposed in this paper to determine key parameters and to guide the design of orienting rotary steerable drilling tool. It is assumed this mathematical model that 1) the eccentric force is concentrated at one point of a mandrel; 2) one end of the mandrel is hinged; and 3) the other end may slide along the axial direction on the support point. The relationship between flexural distortion curve and the axial offsetting (λ) of a mandrel can then be found. The proposed model and the analysis can be used to guide the design of orienting rotary steerable drilling tools.

Proposition d'une methode utilisant les coordonnees cartesiennes pour analyser les distorsions. La methode se caracterise par une definition explicite de la disposition spatiale de la structure de reference et par l'utilisation des coordonnees de symetrie 3N-6(5) qui representent les modifications reelles de la structure moleculaire. Elle est appliquee aux molecules de type ML 4 (T d ) et ML 6 (O h )

Video representations that support view synthesis based on depth maps, such as multiview plus depth (MVD), have been recently proposed, raising interest in efficient tools for depth map coding. In this paper, we derive a new distortion metric that takes into consideration camera parameters and global video characteristics in order to quantify the effect of lossy coding of depth maps on synthesized view quality. In addition, a new skip mode selection method is proposed based on local video characteristics. Experimental results with the proposed mode selection scheme show coding gains of up to 2 dB for the synthesized views, as well as better subjective quality.

Three distortions of pulsed terahertz (T-ray) signal measured with a chirped optical probe pulse are analyzed theoretically. The first distortion originates from the mismatch of the relationship between the optimal chirped probe pulse duration T co and the T-ray length T; the second one stems from the function f(t'/T 0 ); the third one occurs when k<

A model for the analysis of distortion of a large thrust bearing pad is proposed. The analysis aims to simulate the realistic conditions in bearings. Free-edge boundary conditions are implemented and spring-supported pads are considered. The Reynolds and biharmonic bending equations are solved using the iterative technique. The inadequacy of this treatment for the bending equation is shown and an alternative approach is outlined. The model is tested for boundary conditions reported in the literature and the results are in good agreement.

This chapter contains sections titled: Eye Diagram Bit Error Rate Jitter Sources and Budgets Noise Sources and Budgets Peak Distortion Analysis Methods Summary References Problems

This paper examines the linearity of 2-MOS MOSFET-C balanced structures using conventional and Graded-Channel (GC) Gate-All-Around (GAA) devices. The distortion analysis has been performed through the evaluation of third order harmonic distortion (HD3). The study has been carried out through experimental results, two-dimensional process and device simulations. Along this work, the best operation bias in terms of HD3 is determined for each analysed device and the couple device that exhibits lower HD3 is pointed out. The use of GC GAA devices in 2-MOS structures has showed to improve the linearity in relation to the conventional GAA. Finally, a discussion over the non-linearities causes is performed clarifying their origins and the improvement provided by the adoption of GC GAA devices in 2-MOS structures.

Streak cameras applied to inertial confinement fusion research and flashless imaging lidar require large working areas. However, the larger the working area, the bigger the temporal distortion is. And the temporal distortion has a great influence on the detecting precision of the streak camera, resulting in an image distortion on the screen. Yet previous streak camera design work emphasized shorter time resolution and higher special resolution with paying less attention to the temporal distortion extent. Key factors that may affect the temporal distortion are thoroughly analyzed in this paper. We calculate the electric field of a small-size streak tube with the aid of the Computer Simulation Technology Particle Studio software which is a three-dimensional electromagnetic simulation software based on finite integration technology. Axial electric field distributions at different distances to the axis of the small-size streak tube are displayed. The electron trajectories launched from different points on photocathode of the streak tube are tracked through interpolating pre-calculated electromagnetic field to the particle position. It is known that curved photocathode can reduce the temporal distortion, so we calculate the temporal distortions of streak tubes whose radii of curvature of the photocathode are 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, and 55 mm respectively to ascertain how the curvature influences the temporal distortion. The results show that the temporal distortion is mainly produced in the photocathode-to-deflector region, and it is negligible in the equipotential region. Also, bigger radius of curvature of the photocathode leads to a positive temporal distortion, and smaller one leads to a negative temporal distortion. And the absolute value of the temporal distortion increases with the increase of the slit length. The small-size streak tube whose radius of curvature of the photocathode is 40 mm owns the smallest temporal distortion. We also calculate the temporal distortions of electrons launched from the different positions of the photocathode with different initial energies, and the initial energy has little influence on the temporal distortion. To sum up, the dominating factor that produces the temporal distortion is the curvature of the photocathode. The slit image under a ramp sweeping voltage on screen is curved due to the temporal distortion. And the bigger the temporal distortion, the greater the curvature of the slit image is. Besides, a linear relation between the temporal distortion and deflection of the slit image is displayed. The spatial resolutions of the streak tubes with the radii of curvature of the photocathode 30 mm, 40 mm, 50 mm are calculated respectively. And the small-size streak tube whose radius of curvature of the photocathode is 30 mm has the highest spatial resolution. The radius of curvature of the streak tube photocathode should be carefully selected according to actual requirements for the streak camera. Through the analysis we provide a significant guidance for streak tube design.

The rotational spectra of CHF2 35Cl and CHF2 37Cl (CFC22) in the vibrational ground state between 42 and 214 GHz are reported. A centrifugal distortion analysis up to the sixth order is carried out.

This paper introduces the reader to a VHDL-AMS (an IEEE-endorsed standard modeling language, standard 1076.1) implementation of the basic Statistical Eye Analysis algorithm. The main purpose of this paper is to show how such algorithms can be implemented using VHDL-AMS, and not to discuss the derivation details, novelty or usefulness of the algorithms. The example code that accompanies this paper is fully functional, but many more features and refinements need to be added to it to make it ready for real-world design work. The topic of this paper is essentially a continuation of the presentation given by the author on "Peak Distortion Analysis Implemented in VHDL-AMS".

Delayless subband filtering structure, as a high performance frequency domain filtering technique, is used for canceling broadband fMRI noise (8 kHz bandwidth). In this method, adaptive filtering is done in subbands and the coefficients of the main canceling filter are computed by stacking the subband weights together. There are two types of stacking methods called FFT and FFT-2. In this paper, we analyze the distortion introduced by these two stacking methods. The effect of the stacking distortion on the performance of different adaptive filters in FXLMS algorithm with non-minimum phase secondary path is explored. The investigation is done for different adaptive algorithms (nLMS, APA and RLS), different weight stacking methods, and different number of subbands.

The modern wireless communication techniques are aiming on increasing bandwidth and the number of carriers for higher data rate. This sets challenging linearity requirements for RF power amplifiers (PAs). Unfortunately, high linearity can only be obtained at the cost of efficiency. In order to improve the performance of the PA, in-depth understanding of nonlinear behaviour is mandatory. This calls for techniques that can give componentwise information of the causes of the distortion. The aim of this thesis is to develop a technique that can provide such information. This thesis proposes a detailed distortion analysis technique that is based on frequency domain fitting of polynomial models. Simulated large-signal spectra are used for fitting as these contain the necessary information about the large-signal bias point and amplitude range. Moreover, in the frequency domain the delays are easy to compensate, and detailed analysis to any fitted tone can be performed. The fitting procedure as such is simple but becomes difficult in multi-dimensional nonlinearities if the controlling voltages correlate strongly. In this thesis the solvability and reliability of the fitting procedure is increased by numerical operations, model-degree reduction and by using different excitations. A simplified Volterra method is used to calculate the distortion contributions by using the fitted model. The overall distortion is analysed by calculating the voltage response of the contributions of each nonlinearity to the terminal nodes of the device by the use of linear transfer functions of the circuit. The componentwise analysis is performed by phasor presentation enabling the cancelling mechanisms to be seen. The proposed technique is implemented on top of harmonic balance simulation in an APLAC circuit simulator in which extensive distortion simulations are performed. The technique relies on the existing device model and thus the fitted model can be only as accurate as the particular simulation model. However, two different RF PAs are analysed that show a good agreement between measurements and simulations. The proposed technique is verified with several test cases including amplitude dependent amplitude and phase distortion, intermodulation distortion sweet spots, bandwidth dependent memory effects and impedance optimization. The main finding of the detailed analysis is that the distortion is a result of several cancelling mechanisms. In general, cubic nonlinearity of transconductance is dominating the in-band distortion but is cancelled by the 2nd-degree nonlinearity that is mixed to the fundamental band from envelope and 2nd harmonic bands that is usually the main cause of memory effects.

In this paper, we study the rate-distortion performance of our two proposed multiplierless lifting-based IDCT approximations. The proposed IDCT approximations comprise of butterflies and dyadic-rational lifting steps that can be implemented using only shift and add operations, and allows the computational scalability with different accuracy-versus-complexity trade-offs. As rounding approximation leads to the truncation errors in the lifting steps, we estimate the worse-case truncation errors of our IDCT schemes as the distortion performance measurement. Because the cost of a hardware bit shift operation is negligible as compared with that of an addition operation, the overall rate cost is measured by the total minimal number of additions required to complete the IDCT multiplierless implementations. Through the rate and distortion analysis, we obtain the rate-distortion (RD) curves of 32-bit fixed-point implementations of our IDCT structures. From these RD curves, we present two complementary optimal solutions. The first optimal solution can pass IEEE-1180 test with the minimal number of additions. The second optimal solution can result in the finest IDCT approximations compared with the floating-type IDCT. Moreover, our RD analysis confirms that the solution proposed in (L. Liu and T.D. Tran, 2007) is RD-optimized and has a very good performance in terms of accuracy and complexity.

BSIM4 model is not suitable for distortion analysis of circuits with bias point [Formula: see text], such as passive mixers and RF switches, due to discontinuities in higher order derivatives. Surface potential based PSP model has continuous derivatives to at least third-order, and is therefore suitable for intermodulation products simulation. This paper presents the case study of BSIM4 to PSP model conversion flow and comparison of active and passive mixers and SPDT RF switch simulation results. Simulation results show good agreement of original BSIM4 and converted PSP models’ CV, IV, compression point, conversion loss and noise figure, which validates the conversion flow. The converted model has a correct third-order intermodulation products (IM3) slope of three, allowing the simulation of intermodulation products, which was not possible with the original BSIM4 model.

A new computational technique for nonlinear distortion is presented. Unlike Volterra series this technique doesn't require computation of the second and third derivatives of device models. The approach is oriented for implementation in Spice-like simulators.

In this paper a recently proposed detailed distortion analysis technique is extended to apply in a rather complex VBIC model that contains multidimensional current and charge models. The technique is implemented on top of normal harmonic balance simulation, and it is based on fitting polynomial models for all nonlinear I-V and Q-V sources of the device, and using these to calculate the various contributions of IM3 distortion. The technique is used to analyze a 2 GHz InGap HBT power amplifier that shows strong bandwidth dependent signal-induced bias shift.

This paper presents a method for modular robot joint that integrates mechanical part and control system. After the analysis of stress and distortion, it sets up a matrix model with errors. At the same time, PCI adapter and DSP servo controller are designed. The characteristics of the module are tested and analyzed. The main characteristics meet the design target.

An appropriate distortion analysis requires an accurate modeling of the MOSFET drain current derivatives. We discuss and develop a compact MOSFET modeling scheme in order to obtain accurate descriptions of the drain current and its derivatives up to the 5th order. We have analyzed the physical effects which govern the behavior of the 3rd derivative in long and deep-submicron channel MOSFETs. Our modeling agrees well with experimental data and describes continuous transitions between operating regimes, thanks to the use of continuous functions, which do not introduce any artificial peaks.

This paper analyzes signal separation and distortion in a feedforward blind source separation (BSS) applied to convolutive mixture environment. In the BSS learning, a separation block is adjusted so as to make the output signals statistically independent. One direction for this adjustment is to extract only one signal source at a single output. The other direction is to make the output signal spectra white. The second direction causes signal distortion and conflicts with the first direction. This confliction prevent signal separation. These relations are also dependent on a length of the impulse responses in the mixture and the filter length in the separation block. These properties are theoretically analyzed and are investigated through simulations using the white signal sources and the speech signal sources.