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A method proposed for halting weight drift in neural-adaptive control schemes is analyzed using the method of describing functions. The method utilizes a self-evaluating, introspective method with a Cerebellar Model Arithmetic Computer. The average error within the domain of local basis functions is measured, and then used to estimate the effect of weight updates on reducing the error i.e. estimating a partial derivative. The adaptation algorithm halts the weight updates when it is determined that weight updates are no longer beneficial in reducing the average error. In this paper, a describing function analysis establishes stability assuming an accurate measure of the partial derivative.

The Vibrant Soundbridge, a semi-implantable hearing device for subjects with moderate to severe sensorineural hearing impairment was introduced commercially. First audiologic results are presented on 63 patients from 10 European implant centers. Hearing loss was at 0.5, 1, 2, and 4 kHz varying between 43 and 81 dB HL. The patients used the analogue audio processor, type 302. Measured sound-field gain was compared with NAL-R target values. For most patients an acceptable agreement was found. There was a subgroup of patients, however, with relatively low gain. The results suggest that this was related to the suboptimal positioning and fixation of the transducer to the incus.

Six subjects fixated an imagined space-fixed target in darkness, or a visible target against a structured visual background, while rotating their heads actively in yaw, pitch and roll at four different frequencies, from 0.3 to 2.4 Hz. We used search coils to measure the 3-dimensional rotations of the head and eye, and described the relation between them – the input-output function of the rotational vestibulo-ocular reflex (VOR) – using gain matrices. We found consistent cross-coupling in which torsional head rotation evoked horizontal eye rotation. The reason may be that the eyes are above the axis of torsional head rotation, and therefore may translate horizontally during the head motion, so the VOR rotates them horizontally to compensate. Torsional gain was lower than horizontal or vertical, more variable from subject to subject and decreased at low frequencies. One reason for the low gain may be that torsional head rotation produces little retinal slip near the fovea; hence little compensatory eye motion is needed, and so the VOR reduces its torsional gain to save energy or to approximate Listing's law by keeping ocular torsion near zero. In addition, the human VOR has little experience with purely torsional head rotations and so its adaptive networks may be poorly trained for such stimuli. The drop in torsional gain at low frequencies can be explained based on the leak in the neural integrator that helps convert torsional eye-velocity commands into eye-position commands.

A low-gain design for linear discrete-time systems subject to input saturation was recently developed to solve both semi-global stabilization and semi-global output regulation problems. This paper proposes an improvement to the low-gain design and determines controllers with the new design that achieve semi-global output regulation. The improvement is reflected in better utilization of available control capacity and consequently better closed-loop performance.

A measurement system for determining the gain distributions of avalanche photodiodes (APDs) in a low gain range is presented. The system is based on an ultralow-noise charge--sensitive amplifier and detects the output carriers from an APD. The noise of the charge--sensitive amplifier is as low as 4.2 electrons at a sampling rate of 200 Hz. The gain distribution of a commercial Si APD with low average gains are presented, demonstrating the McIntyre theory in the low gain range., 3 pages, 4 figures

We show that semiglobal stabilization of a large class of feedforward nonlinear systems is achieved by low-gain linear feedback provided that the separation of the gains is sufficient. Particular situations are identified where the tuning of the gains only requires increasing powers of a single parameter. A recursive tuning of independent parameters is necessary in the general case to avoid vanishing regions of attractions.

The problem of global almost disturbance decoupling problem with stability for nonlinear system is revisited and is shown to be solvable for a class of nonlinear systems whose zero dynamics contains a chain of integrators affected by disturbance. This result complements some recent work on the topic, where unstable zero dynamics is not allowed to be affected by the disturbances.

A well known control system which can reduce the adverse effect of a periodic disturbance with single frequency is the disturbance obsever. However, in many cases of industrial systems disturbance frequency is varied for some frequency range. Therefore, it may be difficult to reduce the adverse effect of the disturbance by the use of the traditional disturbance observer.In this paper, a design method of new disturbance observer which can cope with the frequency variation is proposed. The main idea of this design method is to synthesize the disturbance observer as a gain-scheduled controller. The proposed disturbance observer is constructed as low degree and low gain controller with superior steadystate characteristic. As compared with the traditional disturbance observer and the H∞ controller, the usefulness of the proposed disturbance observer was shown by numerical simulations.

This paper investigates the problem of state-feedback stabilization for a class of upper-triangular stochastic nonlinear systems with time-varying control coefficients. By introducing effective coordinates, the original system is transformed into an equivalent one with tunable gain. After that, by using the low gain homogeneous domination technique and choosing the low gain parameter skillfully, the closed-loop system can be proved to be globally asymptotically stable in probability. The efficiency of the state-feedback controller is demonstrated by a simulation example.

The Visible FEL oscillator experiment at BNL is designed to lase at 530 nm using the 50 MeV high-brightness ATF electron beam and a micro-undulator of 8.8 mm period. The relatively low energy and short wavelength of this FEL require a high-quality electron beam. In this paper, we study the necessary electron beam requirements via a one-dimensional first-order simulation method. This method takes into account the finite length of the micropulse and the bandwidth of the spontaneous emission. It assumes a long electron pulse, weak optical fields, and low gain. For our experiment, startup time is of particular concern because of the limited length of the macropulse. The simulation method is extended to include the effects of emittance and energy spread. The expected gain and startup conditions for different beam parameters are compared with measured parameters. Scaling of gain versus beam parameters is examined and an experiment is proposed to verify these results.

This letter describes the design and performance of a dual band tri-mode receiver front-end compliant with the IEEE 802.11a, b, and g standards. The receiver front-end was built in a 0.18-/spl mu/m CMOS process and achieves a noise figure of 4.7 dB/5.1 dB for the 2.4-GHz/5-GHz bands, respectively. The receiver front-end provides a dual gain mode of 5 dB/30 dB with an IIP3 of -1dBm for the low gain mode. The front-end draws 25 mA/27 mA from a 1.8-V supply for the 2.4-GHz/5-GHz bands, respectively.

This paper studies the flocking problem for a multi-agent system, where each agent is a vehicle with nonholonomic dynamics. In particular, we consider the case where the agents are subjected to an arbitrarily large communication delay. A distributed low gain control law is derived based on the gradient of an artificial potential function. We demonstrate using the Lyapunov functional approach that the proposed control law drives the multi-agent system into the stable flocking behavior. The effectiveness of the proposed control law is verified in numerical simulation.

International audience; The goal of this paper is to provide design considerations for the use of low gain amplifier presents in the Multiplying Analog-to-Digital Converter (MDAC) of pipelined ADCs with gain error correction in the digital domain. Using low gain amplifier in the MDAC makes the pipelined ADC more susceptible to gain variation and harmonic distortion, impacting the ADC performance. Theory and simulations are presented to provide design insight into the trade-off between minimum gain and its variations to preserve the calibrated ADC performance. These considerations are demonstrated on the MDAC of a 12 bit digitally calibrated pipelined ADC designed in 40nm CMOS technology.

A wideband LC voltage controlled oscillator (VCO) is presented in this work. Measurements show a wide relative tuning range of 37.6% from 4.57 GHz to 6.69 GHz with a tuning voltage from 0 to 3 V. Using an integrated divide-by-2 circuit, both the 2.4 GHz and 5.8 GHz ISM bands can be covered. A key feature is the low gain variation, which stays below 12.5 % up to 6GHz and below 33.3% for the whole tuning range. At 5.725 GHz, the phase noise at 1MHz offset was measured to -105dBc/Hz. The VCO core consumes 4mA of current from a 3V supply voltage. It is implemented using an IBM 180nm SiGe BiCMOS process and the core area amounts to 0.5mm×0.4 mm.

This paper is concerned with the design of state feedback controllers in order to achieve an objective called perfect regulation (p.r.). Necessary and sufficient conditions for the existence of state feedback controllers that achieve p.r. are derived for general linear multivariable time-invariant discrete-time systems. More importantly, an explicit eigenstructure assignment procedure by state feedback that achieves p.r. is developed.

A simple model for the nonlinear low gain evolution of a short pulse Compton free electron laser (FEL) oscillator is derived. An analysis of the small signal regime allows the calculation of the shape of the produced optical pulse. For small excess over threshold, a Landau-Ginzburg equation is obtained, which allows us to show that a strong superradiant efficiency enhancement occurs at small detuning. Furthermore, the knowledge of the eigenfrequencies in the small signal regime allows one to infer a scale law for the period of limit cycles occurring at larger excess over threshold. Theoretical results are compared to experimental results from FELIX.

A low gain design for linear discrete-time systems subject to input saturation was recently developed in (Lin and Saberi 1995a, Lin et al. 1995a, Mantri et al. 1995) to solve both semi-global stabilization and semi-global output regulation problems. This paper proposes an improvement to the low gain design and determines controllers with the new design that achieve semi-global output regulation. The improvement is reflected in better utilization of available control capacity and consequently better closed-loop performance.

We discuss wave-guide Free Electron Laser gain formulae including inhomogeneous broadening and saturation effects. The analysis is not limited to the low gain regime. It is also proven that, after a proper redefinition, most of the “empirical” formulae exploited for the free space case can be utilised to model the wave-guide evolution.

Excessive deposition of central body and abdominal (centripetal) fat early in life often will presage the later development of cardiovascular and metabolic diseases. Data from urban, low-income women from Camden, New Jersey, were used to examine the influence of gestational weight gain on patterns of weight change and fat deposition in 118 young women followed over two consecutive pregnancies. Adjusting for confounding factors, there was a significant (P 29.0 in the subsequent postpartum but not the index postpartum) increased significantly with gestational gain: 4.7% with low gain, 7.0% with recommended gains, and 25.0% with excessive gain. There were similar dose-response increases related to gestational weight gain in all skinfolds (suprailiac, subscapular, and triceps) and the sum of the skinfolds. However, in women with excessive gains, fat was increased disproportionately at upper (+52%) and lower (+48%) central body sites, compared with the periphery (+27%), and compared with increases in women with lesser gestational gains. Thus, excessive gestational weight gain, which is common among low-income women, may be a factor which promotes obesity and a centripetal fat pattern during the reproductive years, thereby increasing the risk for cardiovascular and metabolic diseases in later life. © 1996 Wiley-Liss, Inc.

We study the modifications induced on the longitudinal dynamical behaviour of an e-beam circulating in a Storage-Ring (S.R.) and undergoing a FEL interaction. We discuss the low gain amplifier case and, using the Fokker-Planck equation, evaluate the effect of the FEL interaction on the longitudinal damping time, which is shown to be a function of the detuning parameter and of the intensity itself. We develop a self-consistent model of the S.R. FEL dynamics capable of including saturation, induced energy spread and damping time modifications. The model is shown to be particularly useful to investigate the system evolution and the interplay between the various features causing the saturation of the device.

Limited by pump brightness and high thermal-loading density, low-gain lasers suffering reabsorption losses have an ally in planar waveguides for efficient power scaling. Current performance and future prospects are presented for this laser architecture.

The non‐steady‐state self‐consistent equation in the linear regime of the free‐electron laser (FEL) and the low gain formulas in the non‐steady‐state FEL are derived in this paper. It is found that due to slippage the nonuniformity effect in the longitudinal distribution of the electron beam density is dominant in the influence of the electron pulse length on the gain of the FEL.

SynopsisSmooth pursuit performance in schizophrenia and affective disorders has generally been found to be abnormal using a variety of measures. The purpose of this study was to assess patients with these disorders and normal controls in order to compare the different measures across diagnoses. Smooth pursuit was assessed using quantitative specific measures (gain, catch-up saccade rate and amplitude, square-wave jerk rate, number of anticipatory saccades and total time scored), as well as two global measures: root mean-square error (RMS) and qualitative rating. As previously reported, patients with schizophrenia had low gain, increased catch-up saccade rate and spent less time engaged in scoreable smooth pursuit than normal controls. Patients with affective disorders were not statistically different from controls on any of these measures, and had significantly higher gain than patients with schizophrenia. RMS error and qualitative rating measures were highly correlated (r = 0·87). In linear regression analyses, the quantitative specific measures were highly significant predictors of both RMS error and qualitative ratings (P < 0·0001). Linear regression analyses and a modelling study indicated that one quantitative specific measure, the percent of time engaged in scoreable smooth pursuit (total time scored), was most related to global ratings. However, RMS error and qualitative ratings were less sensitive than total time scored to the difference between controls and patients with schizophrenia. These data indicate two smooth pursuit performance deficits in schizophrenia: patients spend less time engaged in scoreable smooth pursuit and have low gain (accompanied by increased compensatory saccades) when the smooth pursuit is engaged.

The smooth pursuit eye tracking deficit (ETD) often associated with schizophrenia has generated enormous interest over the last 20 years. The deficit is observed in about 80% of schizophrenics and in half of their first degree relatives. It is not affected by neuroleptic medication and is not due to inattention. A review of 52 studies (and actual records when available) on ETD in schizophrenia reveals that the deficit can consistently be described as low gain pursuit augmented with catch-up saccades and often peppered with intrusive saccades. A review of the brain areas that have been shown to be involved in pursuit provides the necessary background for the subsequent section which details the nature of the smooth tracking deficits following experimental lesions. This section reveals that the ETD following lesions of the frontal lobe is unique in that it closely resembles the ETD of schizophrenics. This finding lends further support for frontal lobe theories of schizophrenia.

Intercept points are often used to describe the non-linear performance of transceiver stages. This letter introduces an intercept measure. The intercept measure is a performance parameter including both intercept point and gain parameters. Particularly for low gain stages the intercept measure is useful and is better to use than the traditional output intercept point. The intercept measure is very useful as a single non-linear performance parameter. Copyright © 2003 John Wiley & Sons, Ltd.

This paper studies the consensus among identical agents that are at most critically unstable and coupled through networks with uniform constant communication delay. An achievable upper bound of delay tolerance is obtained which explicitly depends on agent dynamics and network topology. The dependence on network topology disappears in the case of undirected networks. For any delay satisfying this upper bound, a controller design methodology without exact knowledge of the network topology is proposed so that the multi-agent consensus in a set of unknown networks can be achieved. Moreover, when the network topology is known, a larger delay tolerance is possible via a topology-dependent consensus controller. The results are illustrated by simulations.

We used adaptation to high and low gains in a virtual reality setup of the hand to test competing hypotheses about the excitability changes that accompany motor learning. Excitability was assayed through changes in amplitude of motor evoked potentials (MEPs) in relevant hand muscles elicited with single-pulse transcranial magnetic stimulation (TMS). One hypothesis is that MEPs will either increase or decrease, directly reflecting the effect of low or high gain on motor output. The alternative hypothesis is that MEP changes are not sign dependent but rather serve as a marker of visuomotor learning, independent of performance or visual-to-motor mismatch (i.e., error). Subjects were required to make flexion movements of a virtual forefinger to visual targets. A gain of 1 meant that the excursions of their real finger and virtual finger matched. A gain of 0.25 (“low gain”) indicated a 75% reduction in visual versus real finger displacement, a gain of 1.75 (“high gain”) the opposite. MEP increases (>40%) were noted in the tonically activated task-relevant agonist muscle for both high- and low-gain perturbations after adaptation reached asymptote with kinematics matched to veridical levels. Conversely, only small changes in excitability occurred in a control task of pseudorandom gains that required adjustments to large errors but in which learning could not accumulate. We conclude that changes in corticospinal excitability are related to learning rather than performance or error.

As personalized biologically-assisted models of the spine have evolved, the normalization of raw electromyographic (EMG) signals has become increasingly important. The traditional method of normalizing myoelectric signals, relative to measured maximum voluntary contractions (MVCs), is susceptible to error and is problematic for evaluating symptomatic low back pain (LBP) patients. Additionally, efforts to circumvent MVCs have not been validated during complex free-dynamic exertions. Therefore, the objective of this study was to develop an MVC-independent biologically-assisted model calibration technique that overcomes the limitations of previous normalization efforts, and to validate this technique over a variety of complex free-dynamic conditions including symmetrical and asymmetrical lifting. The newly developed technique (non-MVC) eliminates the need to collect MVCs by combining gain (maximum strength per unit area) and MVC into a single muscle property (gain ratio) that can be determined during model calibration. Ten subjects (five male, five female) were evaluated to compare gain ratio prediction variability, spinal load predictions, and model fidelity between the new non-MVC and established MVC-based model calibration techniques. The new non-MVC model calibration technique demonstrated at least as low gain ratio prediction variability, similar spinal loads, and similar model fidelity when compared to the MVC-based technique, indicating that it is a valid alternative to traditional MVC-based EMG normalization. Spinal loading for individuals who are unwilling or unable to produce reliable MVCs can now be evaluated. In particular, this technique will be valuable for evaluating symptomatic LBP patients, which may provide significant insight into the underlying nature of the LBP disorder.

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz., 8 pages, 5 figures

When constructing conventional sliding control law, it is well known that the magnitude of a particular discontinuous control effort must be chosen sufficiently large to counteract any mismatch between the model used for controller design and the real system. However, this usually leads to conservative designs with strong discontinuity appearing in the control signals. Techniques are available to smooth the discontinuity, but these cause performance degradations. In addition for an arbitrary given small switching gain, the approaching phase might not be fulfilled immediately and thus the system stability might not be guaranteed. Consequently, this paper develops a stability guaranteed sliding controller subject to light and size-fixed switching effort. The design problem is formulated as certain constrained feasibility problems, which are solved by using linear matrix inequalities (LMIs). Therefore, high gain behavior can be avoided. By using the low gain based sliding controller, prescribed sliding modes can be attained in finite time for any arbitrary given initial positions.

For stabilization of linear systems subject to input saturation, there exist four different approaches of low-gain design all of which are independently proposed in the literature, namely direct eigenstructure assignment, H 2 and H ∞ algebraic Riccati equation (ARE) based methods, and parametric Lyapunov equation based method. We show here all these methods are rooted in and can be unified under two fundamental control theories, H 2 and H ∞ theory. Moreover, both the H 2 and H ∞ ARE based methods are generalized to consider systems where all input channels are not subject to saturation, and explicit design methods are developed.

The modification induced in the Optical-Klystron gain by an e-beam with non-negligible energy spread and emittances is analyzed. The analysis is carried out including the inhomogeneous broadening contributions due to the undulators and dispersive parts. The paper deals essentially with the low gain regime, the corrections due to the high gain effects are also discussed.

Adaptive arrays and sidelobe cancelers reduce the radar vulnerability to noise interference through matrix inversion techniques which are computationally burdensome. This paper presents a new approach to canceling noise interference using main and auxiliary phased arrays. The main array is high gain and is operated in sequential mode, while the auxiliary array is a low gain receive-only array. Sequential mode operation improves the system's resolution and SNR as well as reduces the sidelobes to insignificant levels. Two information sequences are accumulated on the basis of equal phase at the outputs of the arrays. The two-way target patterns are computed as the Discrete Fourier Transformation of the information sequences. Noise interference is reduced to about — 70 dB through averaging the main and auxiliary spectra. Computer simulation examples validate and demonstrate the new technique.

The future belongs to multiband bandwidth-on-demand mobile networks. Simply reconfigurable mobile devices will be the key to handle the increasing number of bands as well as the varying bandwidth requirements. The LNA constitutes the first block of the receiver chain and therefore has to implement the highest level of reconfigurability. A shunt feedback LNA has been designed that can be used for multiple frequency bands. The proposed LNA has two gain steps incorporating a wideband match of at least −10 dB. Below 2 GHz the minimum gain is above 26 dB and the noise figure is below 1.9 dB. Below 1 GHz the gain is above 30 dB and the noise figure is below 1.5 dB. The IIP3 in low gain mode is least 5.8 dBm. The results have been obtained using a current of 8.7mA from a 1.4V supply in a 90 nm CMOS technology.

An all digital time amplifier (TA) is proposed in 0.13 μm CMOS process. The TA is based on quantization scheme; hence it guarantees large input range. An interpolation scheme is employed to achieve more than 2 times reduction in gain variation of the TA over the input range. The all digital TA is portable to other process technology with smaller design effort. The TA shows a gain variation of less than 5% and consumes a power of 14 mW.

Microstrip antennas are highly suitable structures for modern communication systems due to their inherent properties like low cost, small size, light weight, easy integration with host surface [1–2]. However their narrow bandwidth and low gain becomes main constraint in their practical applications. In recent times, extensive work for the improvement of bandwidth and gain has been reported [3–4]. The circularly polarized patch antennas are found useful in different communication systems and several circularly polarized patch geometries with improved performance may be seen in available literature on antennas [5–6]. In this communication, a novel antenna design is proposed to achieve circular polarization with much improved impedance bandwidth.

Binocular cyclorotatory (torsional) eye movements in response to visual patterns, which oscillated sinusoidally in the frontal plane, were recorded with scleral induction coils in human subjects. Conjugate cycloversion and disjunctive cyclovergence were directly compared by in-phase and out-of-phase oscillation of the same pattern. Stimulus motion had a frequency of 0.2 Hz and amplitudes of 2–8 deg. Both response types had a similar and low gain (about 0.2 averaged over all subjects). Cycloversion showed no time lag, while cyclovergence lagged by about 600 msec. Non-fusible patterns were effective in eliciting cycloversion, but not cyclovergence. Apart from this, the nature of the pattern (randomly distributed dots, regular rows of dots, horizontal or vertical grating, Julesz stereogram or images with a pictorial significance) had only the slightest effect on the magnitude of the responses.

Smooth pursuit eye movements were studied with infrared reflection equipment in 10 patients with myotonic dystrophy and in 10 age- and sex-matched controls. Smooth pursuit gain, measured after correction for catch-up saccades, was decreased in the patient group Normal latencies of saccadic eye movements made a lack of attention an unlikely explanation for this low gain Likewise, presence of catch-up saccades and normal fixation made it unlikely that extra-ocular myopathy explained the low smooth pursuit gain We suggest that periventricular white matter abnormalities represent a more likely explanation.

The difficulties of locating earthquakes in the early instrumental period are not always fully appreciated. The networks were sparse, and the instruments themselves were of low gain, often had inappropriate frequency response and recording resolution, and their timing could be unreliable and inaccurate. Additionally, there was only limited knowledge of earth structure and consequent phase identification and propagation. The primitive Zöppritz tables for P and S, with no allowance for the core, did not come into use until 1907, and remained the main model until the adoption of the Jeffreys-Bullen tables in the mid-1930s. It was not until the early 1920s that studies of Hindu Kush earthquakes revealed that earthquake foci could have significant depth. Although many early locations are creditably accurate, others can be improved by use of more modern techniques. Early earthquakes in unusual places often repay closer investigation. Many events after about 1910 are well enough recorded to be re-located by computer techniques, but earlier locations can still be improved by using more recent knowledge and simpler techniques, such as phase re-identification and graphical re-location. One technique that helps with early events is to locate events using the time of the maximum phase of surface waves, which is often well reported. Macroseismic information is also valuable in giving confirmation of earthquake positions or helping to re-assess them, including giving indications of focal depth. For many events in the early instrumental period macroseismic locations are to be preferred to the poorly-controlled instrumental ones. Macroseismic locations can also make useful trial origins for computer re-location. Even more recent events, which appear to be well located, may be grossly in error due to mis-interpretation of phases and inadequate instrumental coverage. A well converging mathematical solution does not always put the earthquake in the right place, and computer location programs may give unrealistically small estimates of error. Examples are given of improvements in locations of particular earthquakes in various parts of the world and in different time periods.

This paper studies some properties of the recently developed parametric Lyapunov equation based low gain feedback design method. As applications of these new properties, alternative and simpler solutions are proposed to the (global) stabilization problem for a class of linear systems with input delay and the semi-global stabilization problem when the systems are in addition subject to actuator saturation. Besides the simplicity in their construction, the new solutions can also be easily scheduled online to achieve global result in the presence of input saturation.

We show that longitudinal and transverse mode correction to the FEL low gain formula can be expressed by means of higher order derivatives of the complex spontaneous emission function. The analysis is then extended to the high gain regime.

A neon 633 nm laser with an unstable cavity was made to lase in the negative unstable region. The characteristic parameters were measured. The loss calculated by using both the geometric approach and the diffraction integral is higher than the gain of the gas mixture, it contradicts the experimental results. If the radial dependence of the gain is taken into account then the calculated loss fits the experimental results satisfactorily.

In this paper a new multi-loop delta-sigma modulator is presented. This multi-loop modulator is insensitive to low gain opamps while maintaining the stability advantage. As a proof of concept, a prototype was implemented to show the functionality of this structure. Measurement results shows that with open-loop opamp gain of only 35 dB, this prototype achieves over 74 dB SNDR at oversampling ratio of 16. The sampling frequency is 20 MHz and the total power dissipation is 3.2 mW from a 1.2 V power supply.

In this study, we assessed the renal cortical echogenicity of clinically normal adult cats by histogram analysis to obtain basic ultrasonographic data. Ultrasound images were taken under the following sets of conditions: (1) high contrast and low gain setting using a convex probe, (2) low contrast and high gain setting using a convex probe, (3) high contrast and low gain setting using a linear probe and (4) low contrast and high gain setting using a linear probe. Echogenicity of the region of interest (ROI) in the right and left renal cortices, liver and spleen was determined by histogram analysis; kidney/spleen (Kid/Sp) and kidney/liver (Kid/Liv) echogenicity ratios were calculated. Kid/Sp and Kid/Liv values varied among different ROI sites in the kidney when obtained using the convex probe, but were constant when obtained using the linear probe. Kid/Sp measured in the middle sites of the kidney showed similar values for the different settings; however, Kid/Liv differed between probes. The present findings suggest that determination of Kid/Sp using a linear probe is a feasible method for quantitative evaluation of renal cortical echogenicity in cats.

Terminal sliding mode (TSM) control is known for its high gain property nearby the vicinity of the equilibrium while retaining reasonably low gain elsewhere. This is desirable in digital implementation where the limited sampling frequency may incur chattering if the controller gain is overly high. In this work we integrate a linear switching surface with a terminal switching surface. The mixed switching surface can be designed according to the precision requirement. The analysis, simulations and experimental investigation show that the mixed SMC design outperforms the linear SMC as well as the pure TSMC.

We revisit a previous high-low gain control idea for a 4 DOF spherical inverted pendulum using a different approach that provides explicit tuning rules to deal with certain bounded external disturbance. To this end, we propose a design method, inspired by a nested saturation design procedure proposed by Marconi and Isidori, to design some low and high gain controllers to two decoupled subystems of the original system, where explicit tuning rules are given to make two feedback interconnected subsystems satisfying ISS from external disturbances. The update controller is a robust, decentralized and ``global" controller.

The alphaH-factor behavior with current is investigated in a 1.52 mum InAs/InP (311B) QD laser. It is shown that due to low gain compression effects, no divergence of the alphaH-factor occurs unlike 1.3 mum InAs/GaAs QD lasers.

Conventional wigglers made with periods of less than a few centimeters generate light of short wavelength, but usually have low gain because of their low fields. Iron-free electromagnets driven by high pulsed currents can generate the high fields needed. We will discuss the design and construction of such magnets.