Spurious Reduction Research Articles

Movement Detection with Event-Based Cameras: Comparison with Frame-Based Cameras in Robot Object Tracking Using Powerlink Communication

Event-based cameras are not common in industrial applications despite the fact that they can add multiple advantages for applications with moving objects. In comparison with frame-based cameras, the amount of generated data is very low while keeping the main information in the scene. For an industrial environment with interconnected systems, data reduction becomes very important to avoid network congestion and provide faster response time. However, the use of new sensors as event-based cameras is not common since they do not usually provide connectivity to industrial buses. This work develops a network node based on a Field Programmable Gate Array (FPGA), including data acquisition and tracking position for an event-based camera. It also includes spurious reduction and filtering algorithms while keeping the main features at the scene. The FPGA node also includes the stack of the network protocol to provide standard communication among other nodes. The powerlink IEEE 61158 industrial network is used to communicate the FPGA with a controller connected to a self-developed two-axis servo-controlled robot. The inverse kinematics model for the robot is included in the controller. To complete the system and provide a comparison, a traditional frame-based camera is also connected to the controller. Response time and robustness to lighting conditions are tested. Results show that, using the event-based camera, the robot can follow the object using fast image recognition achieving up to 85% percent data reduction providing an average of 99 ms faster position detection and less dispersion in position detection (4.96 mm vs. 17.74 mm in the Y-axis position, and 2.18 mm vs. 8.26 mm in the X-axis position) than the frame-based camera, showing that event-based cameras are more stable under light changes. Additionally, event-based cameras offer intrinsic advantages due to the low computational complexity required: small size, low power, reduced data and low cost. Thus, it is demonstrated how the development of new equipment and algorithms can be efficiently integrated into an industrial system, merging commercial industrial equipment with new devices.

Diagnosing Relationships between Mean State Biases and El Niño Shortwave Feedback in CMIP5 Models

AbstractThe rate of damping of tropical Pacific sea surface temperature anomalies (SSTAs) associated with El Niño events by surface shortwave heat fluxes has significant biases in current coupled climate models [phase 5 of the Coupled Model Intercomparison Project (CMIP5)]. Of 33 CMIP5 models, 16 have shortwave feedbacks that are weakly negative in comparison to observations, or even positive, resulting in a tendency of amplification of SSTAs. Two biases in the cloud response to El Niño SSTAs are identified and linked to significant mean state biases in CMIP5 models. First, cool mean SST and reduced precipitation are linked to comparatively less cloud formation in the eastern equatorial Pacific during El Niño events, driven by a weakened atmospheric ascent response. Second, a spurious reduction of cloud driven by anomalous surface relative humidity during El Niño events is present in models with more stable eastern Pacific mean atmospheric conditions and more low cloud in the mean state. Both cloud response biases contribute to a weak negative shortwave feedback or a positive shortwave feedback that amplifies El Niño SSTAs. Differences between shortwave feedback in the coupled models and the corresponding atmosphere-only models (AMIP) are also linked to mean state differences, consistent with the biases found between different coupled models. Shortwave feedback bias can still persist in AMIP, as a result of persisting weak shortwave responses to anomalous cloud and weak cloud responses to atmospheric ascent. This indicates the importance of bias in the atmosphere component to coupled model feedback and mean state biases.

The VIMOS Public Extragalactic Redshift Survey (VIPERS)

Identifying spurious reduction artefacts in galaxy spectra is a challenge for large surveys. We present an algorithm for identifying and repairing residual spurious features in sky-subtracted galaxy spectra with application to the VIPERS survey. The algorithm uses principal component analysis (PCA) applied to the galaxy spectra in the observed frame to identify sky line residuals imprinted at characteristic wavelengths. We further model the galaxy spectra in the rest-frame using PCA to estimate the most probable continuum in the corrupted spectral regions, which are then repaired. We apply the method to 90,000 spectra from the VIPERS survey and compare the results with a subset where careful editing was performed by hand. We find that the automatic technique does an extremely good job in reproducing the time-consuming manual cleaning and does it in a uniform and objective manner across a large data sample. The mask data products produced in this work are released together with the VIPERS second public data release (PDR-2).

0.7–1.8 GHz multiband digital polar transmitter using watt-class current-mode class-D CMOS power amplifier and digital envelope modulation technique for reduced spurious emissions

A polar transmitter driven by digital input signals for envelope and phase is demonstrated, using a band-switching output resonator to achieve multiband operation. A new digital pulse width modulation algorithm is also shown to partially suppress spurious signals associated with the digital input envelope signal. The transmitter consists of a current-mode class-D (CMCD) CMOS power amplifier (PA), together with a buck converter with a dead-time generator for improved efficiency. The CMCD PA is tuned by band-switching capacitors that can handle up to 9 V, and is measured to have approximately 30 dBm output power with 31–35% drain efficiency under single-tone testing. The proposed spurious signal reduction technique works to partially suppress quantization noise without increasing power consumption. Overall efficiencies of 27.1/25.6% are obtained at 30.2/28.9 dBm continuous wave (CW) output powers and 0.85/1.75 GHz carrier frequencies, respectively. Spur suppression of 9–10 dB peak is achieved when the proposed algorithm is applied with wideband code division multiple access (WCDMA) modulation.

On the Importance of Image Gating for the Assay of Left Ventricular Mechanical Dyssynchrony Using SPECT

The potential of SPECT for quantifying left ventricular mechanical dyssynchrony is increasingly appreciated. We sought to examine the incidence and impact of image gating errors on this quantification and to test a possible solution for affected studies. First, to establish whether and how gating error alone could affect the measurement of dyssynchrony, we performed a prospective study in which patients with pacemakers were studied twice: during normal rhythm without gating error and with gating error caused by pacemaker-induced dysrhythmia. Second, to understand the pattern and magnitude of gating error during our typical imaging practice, we retrospectively examined studies from a separate cohort of 64 patients who were referred for dyssynchrony evaluation. Third, to understand whether studies with gating error could be repaired for the purpose of quantifying dyssynchrony, we tested a correction algorithm on the pacemaker-induced dysrhythmia image set to see whether it repaired this set so as to approximate the patients' normal rhythm image data. We subsequently applied this algorithm to the 64-patient cohort. Pacemaker-induced gating error caused a spurious decrease in dyssynchrony magnitude. Among the 64-patient cohort, similar gating errors were common, and an inverse exponential relationship between gating-error magnitude and dyssynchrony magnitude was observed. The correction algorithm accurately repaired the pacemaker-induced dysrhythmia image set; when it was applied to the 64-patient cohort, the magnitude of the postcorrection increase in dyssynchrony magnitude was proportional to the magnitude of the gating error. Gating errors cause a spurious reduction in SPECT assay of dyssynchrony magnitude. In our standard imaging practice, gating errors were common. Post hoc correction appears to be feasible.

Comparison of hematologic measurements between local and central laboratories: Data from the BABY HUG trial

ObjectivesTo investigate the concordance of blood count indices measured locally and at a central laboratory. Design and methodsIn a multi-center clinical trial of hydroxyurea therapy in infants with sickle cell anemia (BABY HUG), the concordance between blood count indices measured locally and at a central laboratory was investigated. ResultsLocal laboratory measurements of neutrophil and monocyte counts were significantly higher (44% and 37%, respectively) compared to the central measurements (p<0.0001), and mean corpuscular volume (MCV) was higher centrally. ConclusionOvernight shipping with processing delay causes spurious reductions in absolute neutrophil count (ANC) and absolute monocyte count (AMC) that may result in incorrect monitoring decisions in multicenter clinical trials.

Synthesis of Filters With Stub-Loaded Multiple-Mode Resonators

Exact synthesis of compact and wide-band filters with stub-loaded multiple-mode resonators is investigated in this letter. The multi-mode behavior and characteristics of the proposed filter structure are studied by conventional natural modes analysis. To develop the complete synthesis procedure, a bandpass prototype in the S-plane is used for good spurious suppression and size reduction. Approximation of the driving point impedance then proceeds, with the help of transformed variable. Network elements are then extracted by using Richards' theorem. The method is demonstrated by a design example of a third-order bandpass filter. Although six elements are used in this design, the total length is only one third of the wavelength at its center frequency. The experiment results justify the proposed procedure.

Round your numbers in rank tests: exact and asymptotic inference and ties

Non-parametric statistical tests are commonly used in the behavioral sciences. Researchers need to be aware that non-parameteric methods involving ranks can perform unreliably as a result of very small amounts of noise added in the storage and manipulation of values by computers, causing spurious reduction in the number of ties. In order to avoid this problem, researchers should round values to an appropriate number of decimal places prior to the ranking procedure to ensure that data points whose values cannot be separated according to the precision of their measurement are recorded as having identical rank. We also recommend exact rather than asymptotic evaluation of p values in non-parametric statistical tests.

Spurious Reduction Techniques for DDS-Based Synthesizers

This paper analyzes the spurious sources in DDS synthesizers and deduces the simple model of DDS output signal. The method of feeding pseudo-random noise into the phase accumulator for spurious reduction is discussed. A new method for spurious reduction by compensating for DAC integer nonlinearity is proposed with two DACs and a power combiner. One DAC generates the error signal to compensate for the other DAC INL. The factor how the amplitude error and the phase error between the two combined signals affect the spurious level is also analyzed. The experiment shows that the spurious reduction can be improved by at least 18 dB, which proves the validity of the DAC INL compensation method for the spurious reduction.

A new method of spur reduction in phase truncation for DDS

DDS (Direct digital synthesizer) is widely used for frequency synthesis. The factors that contribute to spurious signals are analyzed. Adding a random signal to DDS system was used for spurious reduction formerly. Those methods assuredly reduce the spurs while the noise floor of signals is worsened. A new spurious reduction technique based on two DDS is proposed. The first DDS generates the conventional sine signal. The other DDS produces the error signal which compensates for the phase truncation error in traditional DDS system. A spurious reduction circuit has been developed. The experimental result indicates that the spurious signal due to phase truncation can be reduced 8dBc at least.

High Speed Surface Micro-Polishing for Spurious Reduction of Small Quartz Crystal Blanks

Surface polishing is required for small crystal blanks to eliminate frequency spurious generated by the infinite rectangular shape. From the productivity viewpoint, bi-convex or plano-cylindrical surface are generally used to realize the energy trapping at the central part of the blanks. So far barrel polishing is the common fabrication technology to obtain bi-convex surface, however, the surface is finished insufficiently and fabrication process takes longer time as the blank size becomes small. To solve this difficulty, two types of new surface micro-polishing mechanisms with fixed abrasive and arrayed blank arrangement are experimentally examined to obtain plano-cylindrical surface. The fastest finishing time of 10 s for a blank is achieved together with the spurious elimination.

The nature of spurious mode suppression in extended FSR microring multiplexers

A systematic approach to the design of extended free spectral range (FSR) series coupled microring multiplexers is described. The aim is to achieve large extension ratios and adequate suppression of the spurious interstitial modes, while moderating radiation enhancing ring diameter reduction as much as possible. Computer simulated results of the transmission and group delay characteristics are presented together with a universal plot for spurious mode suppression vs. relative ring diameter reduction. The significance of closely spaced twin resonances in the extended stopband is recognized. The effect of loss on filter performance, in the passband and in the extended stopband, is also briefly discussed.

An efficient transport protocol for ad hoc networks: An end-to-end freeze TCP with timestamps

In ad hoc networks, loss-based congestion window progression by the traditional means of duplicate ACKs and timeouts causes high network buffer utilization due to large bursts of data, thereby degrading network bandwidth utilization. Moreover, network-oriented feedbacks to handle route disconnection events may impair packet forwarding capability by adding to MAC layer congestion and also dissipate considerable network resources at reluctant intermediate nodes. Here, we propose a new TCP scheme that does not require the participation of intermediate nodes. It is a purely end-to-end scheme using TCP timestamps to deduce link conditions. It also eliminates spurious reductions of the transmission window in cases of timeouts and fast retransmits. The scheme incorporates a receiver-oriented rate controller (rater), and a congestion window delimiter for the 802.11 MAC protocol. In addition, the transient nature of medium availability due to medium contention during the connection time is addressed by a freezing timer (freezer) at the receiver, which freezes the sender whenever heavy contention is perceived. Finally, the sender-end is modified to comply with the receiver-end enhancements, as an optional deployment. Simulation studies show that our modification of TCP for ad hoc networks offers outstanding performance in terms of goodput, as well as throughput.

Gadodiamide administration causes spurious hypocalcemia.

To evaluate the prevalence of spurious hypocalcemia after gadodiamide-enhanced magnetic resonance (MR) imaging. Eight hundred ninety-six inpatients with available serum calcium data obtained before and after gadodiamide-enhanced MR imaging were identified. Changes in serum calcium measurements following gadodiamide administration in 1,049 MR imaging examinations performed in these patients were correlated with gadodiamide dose, renal function, and time between gadodiamide administration and phlebotomy. Following 42 gadodiamide-enhanced examinations, serum calcium measurements spuriously decreased by more than 2 mg/dL (0.5 mmol/L), resulting in laboratory reports of "critical" hypocalcemia (ie, calcium level < 6 mg/dL [1.5 mmol/L]) in 25 examinations. These reduced calcium measurements were correlated with serum creatinine level (r = 0.39, P <.001), gadodiamide dose (r = 0.37, P <.001), and time between gadodiamide injection and phlebotomy (r = -0.28, P <.001). Spurious reductions in calcium measurements after administration of 0.1 mmol of gadodiamide per kilogram of body weight were greater in patients with renal insufficiency (0.6 mg/dL [0.15 mmol/L] +/- 0.5 [0.125, SD]) than in those with normal renal function (0.14 mg/dL [0.035 mmol/L] +/- 0.4 [0.1]) (P <.001). After administration of more than 0.2 mmol/kg of gadodiamide, spurious calcium measurement decreases were greater in patients with renal insufficiency (2.4 mg/dL [0.6 mmol/L] +/- 3.6 [0.9]) than in those with normal renal function (0.4 mg/dL [0.1 mmol/L] +/- 0.7 [0.175]) (P <.001). Patients with renal insufficiency had spuriously low calcium measurements up to 4(1/2) days after gadodiamide administration. Seven patients were inappropriately treated with intravenous calcium and eleven with oral calcium in response to false-positive laboratory reports of critical hypocalcemia. No patient had characteristic symptoms of hypocalcemia or injuries attributed to the inappropriate medical treatment. Gadodiamide administration causes spurious hypocalcemia, particularly at doses of 0.2 mmol/kg or higher and in patients with renal insufficiency.

Prescription duration after drug copay changes in older people: methodological aspects.

Impact assessment of drug benefits policies is a growing field of research that is increasingly relevant to health care planning for older people. Some cost-containment policies are thought to increase noncompliance. This paper examines mechanisms that can produce spurious reductions in drug utilization measures after drug policy changes when relying on pharmacy dispensing data. Reference pricing, a copayment for expensive medications above a fixed limit, for angiotensin-converting enzyme(ACE) inhibitors in older British Columbia residents, is used as a case example. Time series of 36 months of individual claims data. Longitudinal data analysis, adjusting for autoregressive data. Pharmacare, the drug benefits program covering all patients aged 65 and older in the province of British Columbia, Canada. All noninstitutionalized Pharmacare beneficiaries aged 65 and older who used ACE inhibitors between 1995 and 1997 (N = 119,074). The introduction of reference drug pricing for ACE inhibitors for patients aged 65 and older. Timing and quantity of drug use from a claims database. We observed a transitional sharp decline of 110% t a standard error of 30% (P = .02) in the overall utilization rate of all ACE inhibitors after the policy implementation; five months later, utilization rates had increased, but remained under the predicted prepolicy trend. Coinciding with the sharp decrease, we observed a reduction in prescription duration by 31% in patients switching to no-cost drugs. This reduction may be attributed to increased monitoring for intolerance or treatment failure in switchers, which in turn led to a spurious reduction in total drug utilization. We ruled out the extension of medication use over the prescribed duration through reduced daily doses (prescription stretching) by a quantity-adjusted analysis of prescription duration. The analysis of prescription duration after drug policy interventions may provide alternative explanations to apparent short-term reductions in drug utilization and adds important insights to time trend analyses of drug utilization data in the evaluation of drug benefit policy changes.

Pseudophysiologic Emphysema Resulting from Severe Small-Airways Disease

Loss of lung elastic recoil causing hyperinflation with increased TLC and decreased diffusing capacity and expiratory airflow are physiologic hallmarks of emphysema. We studied lung mechanics in 10 patients (seven men and three women) aged 69 +/- 9 yr (mean +/- SD) who had fixed, severe expiratory airflow limitation with a mean FEV1 = 0.73 +/- 0.1 L (mean +/- SD) (32 +/- 7% predicted) and lung computed tomographic picture grade score <= 20, indicating no or trivial emphysema. Three patients died, in whom whole-lung emphysema scores were 15 each and small airways were abnormal. Marked hyperinflation was present in all 10 patients studied, with TLC 7.3 +/- 1.1 L (140 +/- 12% predicted); FRC 5.6 +/- 0.8 L (177 +/- 30% predicted); and RV 5.2 +/- 0.8 L (242 +/- 28% predicted). Diffusing capacity of carbon monoxide (DLCO was reduced, at 12 +/- 6 ml/min/mm Hg (61 +/- 29% predicted). The pressure-volume curves of the lung were markedly abnormal. Pst(L) at TLC was 11.6 +/- 1.4 cm H2O. Transdiaphragmatic pressure (Pdi) in five patients was 66 +/- 13 cm H2O. These results indicate that severe small-airways disease with no or trivial emphysema may cause a spurious reduction in diffusing capacity as well as severe loss of lung elastic recoil resulting in marked hyperinflation, increased TLC, and decreased Pdi and expiratory airflow.

Electrophoretic artifacts arising from the use of thiol-containing reagents.

Thiol reagents migrate as a curtain behind the salt front when loaded with the sample solution onto disc-electrophoresis gels. In immobilized pH gradients (IPG) the same compounds are driven by electrophoresis and electroosmosis from the alkaline to the neutral and acidic regions of the gradients. In either case, a dose-dependent sideways spreading results in spurious reduction between adjacent lanes if samples with and without reducing agent are loaded side by side.

Cosmic abundances of stable particles: Improved analysis

An exact relativistic single-integral formula for the thermal average of the annihilation cross section times velocity, the key quantity in the determination of the cosmic relic abundance of a species, is obtained. Since it does not require expansion of the cross section at low relative velocity, it can also be used when the cross section varies rapidly with energy, e.g. near the formation of a resonance or the opening of a new annihilation channel. We discuss approximate formulas in these cases, and we find that dips in the relic density near resonances are significantly broader and shallower than previously thought and that spurious reductions near thresholds disappear.