Isolated output for class-D dc amplifiers

Transformer-coupled output stage is used with pulse-width modulated class-D dc amplifiers. Circuit is comprised of two channels corresponding to negative and positive input signals. Amplitude of secondary-current triangular pulse is function of duration of driving pulse. Therefore, circuit converts pulse-width modulated driving signal to pulse-amplitude modulated signal

SAR antenna calibration techniques

Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach

Norman Julius Zabusky OBITUARY

Norman Julius Zabusky, who laid the foundations for several critical advancements in nonlinear science and experimental mathematics, died of idiopathic pulmonary fibrosis on 5 February 2018 in Beersheba, Israel. He also made fundamental contributions to computational fluid dynamics and advocated the importance of visualization in science.Published versio

An Analysis of Kinetic Response Variability

Studies evaluating variability of force as a function of absolute force generated are synthesized. Inconsistencies in reported estimates of this relationship are viewed as a function of experimental constraints imposed. Typically, within-subject force variability increases at a negative accelerating rate with equal increments in force produced. Current pulse-step and impulse variability models are unable to accommodate this description, although the notion of efficiency is suggested as a useful construct to explain the description outlined

Square Patterns and Quasi-patterns in Weakly Damped Faraday Waves

Pattern formation in parametric surface waves is studied in the limit of weak viscous dissipation. A set of quasi-potential equations (QPEs) is introduced that admits a closed representation in terms of surface variables alone. A multiscale expansion of the QPEs reveals the importance of triad resonant interactions, and the saturating effect of the driving force leading to a gradient amplitude equation. Minimization of the associated Lyapunov function yields standing wave patterns of square symmetry for capillary waves, and hexagonal patterns and a sequence of quasi-patterns for mixed capillary-gravity waves. Numerical integration of the QPEs reveals a quasi-pattern of eight-fold symmetry in the range of parameters predicted by the multiscale expansion.Comment: RevTeX, 11 pages, 8 figure

Out-of-equilibrium critical dynamics at surfaces: Cluster dissolution and non-algebraic correlations

We study nonequilibrium dynamical properties at a free surface after the system is quenched from the high-temperature phase into the critical point. We show that if the spatial surface correlations decay sufficiently rapidly the surface magnetization and/or the surface manifold autocorrelations has a qualitatively different universal short time behavior than the same quantities in the bulk. At a free surface cluster dissolution may take place instead of domain growth yielding stationary dynamical correlations that decay in a stretched exponential form. This phenomenon takes place in the three-dimensional Ising model and should be observable in real ferromagnets.Comment: 4 pages, 4 figure

Using the Fluvial-Lacustrine Interface in a Glaciodeltaic Deposit to Redefine the Valparaiso Moraine, Berrien County, Michigan, USA

The Valparaiso morainic system in eastern Berrien County, southwestern Michigan, is a 10-18 km-wide continuous belt of collapsed glacial landforms. Previously, the composition of the moraine belt was inferred to be of unsorted materials, including coarse- to fine-textured tills, and some stratified deposits. The moraine boundary was defined primarily on classical geomorphic evidence of relative high elevation, "kettled" or "swell & sag" topography, presence of boulders at the surface, steep ice-contact face, etc. Recent mapping, which included well records, geophysics, and test drilling, revealed the moraine to be composed of glacial meltwater deposits, commonly 30 m thick. The deposits include >50 separate glaciodeltaic morphosequences, mostly ice-marginal deltas, graded to proglacial Lakes Madron (new name) and Dowagiac. Both Lake Madron and younger Lake Dowagiac were dammed to the south by the older Kalamazoo moraine and to the west by the retreating edge of the Michigan ice lobe. Each delta grades from ice-contact landforms underlain by coarse-grained facies at its head to non-collapsed landforms underlain distally by fine-grained facies. Proximal deltaic deposits are coarse grained, locally containing boulders and lenses of poorly sorted flowtill with zones of collapsed bedding along ice-contact slopes. A composite section of a delta, derived from a gravel pit exposure extended by a drillhole showed, from top to bottom: 6 m glaciofluvial sand and gravel; 4.5 m deltaic foreset sand, silt, and gravel, dipping 10o SSE; 9 m pebbly sand; 10.5 m ft coarse to medium sand; 8 m medium to very fine sand and silt at the base; overlying 1.7 m of gray silty diamicton. Deltaic glaciofluvial plains of Lake Madron grade from 256 m altitude to distal distributary plains at 241 m, controlled by the lake level and spillway at 239 m. Lake Dowagiac deltas have fluvial plains as high as 250 m graded to distal plain altitudes of 225 m. The Lake Dowagiac spillway crossed older deposits south of Niles, MI. Both lakes discharged through the St. Joseph River valley south across the regional drainage divide. Wide heads of deltas trending ENE within the Valparaiso moraine belt document ice-margin retreat positions, similar to older ice margins within the outer Kalamazoo Moraine. Correlating the elevations of the heads of deltas and the fluvial/lacustrine interface allowed us to group glaciodeltaic morphosequences by outlet/proglacial lake level and therefore, infer the location of nine ice margins at various stages during construction of the Valparaiso Moraine. The resulting map shows shingled deposits from a highly undulating ice margin, rather than the single, linear margin shown on older maps

Derivation of Amplitude Equations by Renormalization Group Method

A proper formulation in the perturbative renormalization group method is presented to deduce amplitude equations. The formulation makes it possible not only avoiding a serious difficulty in the previous reduction to amplitude equations by eliminating all of the secular terms but also consistent derivation of higher-order correction to amplitude equations.Comment: 6 page, revte

Renormalization Group Method and Reductive Perturbation Method

It is shown that the renormalization group method does not necessarily eliminate all secular terms in perturbation series to partial differential equations and a functional subspace of renormalizable secular solutions corresponds to a choice of scales of independent variables in the reductive perturbation method.Comment: 5 pages, late

Simple Baselines for Human Pose Estimation and Tracking

There has been significant progress on pose estimation and increasing interests on pose tracking in recent years. At the same time, the overall algorithm and system complexity increases as well, making the algorithm analysis and comparison more difficult. This work provides simple and effective baseline methods. They are helpful for inspiring and evaluating new ideas for the field. State-of-the-art results are achieved on challenging benchmarks. The code will be available at https://github.com/leoxiaobin/pose.pytorch.Comment: Accepted by ECCV 201