Robust Envelope Research Articles

Design and Optimization of an Origami Gripper for Versatile Grasping and Manipulation

Robotic grasping and manipulation demand the ability to handle a multitude of objects with different shapes, sizes, quantities, surface smoothness, vulnerability, and stiffness, which is challenging without prior knowledge about object properties. Herein, a novel origami‐inspired gripper for universal grasping is presented. The innovative structure seamlessly transforms a simple uniaxial pulling motion into a flexible and robust envelope or pinch grasp, enabling it to tackle various scenarios. The origami gripper offers distinctive advantages, including scalable and optimizable design, grasping compliance and robustness, providing material flexibility, and providing solutions to challenging manipulation tasks. The working principles of the origami gripper are characterized and analyzed. An optimization‐based inverse design method is presented to adjust gripper properties for various scenarios. Through comprehensive experimentation and evaluation, the gripper's capabilities to grasp various objects with a wide range of distinctive properties, including ultrasoft, slippery, granular, and multiple objects, which is a challenge for the existing robotic grippers, are demonstrated. The research holds promise for transformative applications in areas such as the food industry, waste handling, fine and fragile objects grasping, and environmental sampling.

Robust retrofits for rural house envelope considering construction quality and occupant behavior uncertainties: A MOO-integrated Taguchi method

Due to the underdeveloped socio-economic environment, the uncertainties in construction quality and occupant behavior are more prominent for rural house than urban residential buildings. If these uncertainties are not considered, there are higher risks of inaccurate performance prediction, unrealistic retrofit decisions and causing serious performance gap. To address this challenge, this paper proposes a robust envelope retrofitting workflow that combine deterministic multi objective optimization (MOO) and Taguchi method. This workflow stands out for its utilizing mature deterministic MOO to fast approximate Alternative schemes, and utilizing Taguchi method to handle uncertainties, reducing some key disadvantages of traditional robust design optimization (RDO), such as heavy calculating burden, overly conservative solution and difficulty to predefine proper robust objectives or performance target value. The proposed workflow consists of four main steps, formulating Alternative schemes by deterministic MOO, screening highly sensitive uncertain parameters by uncertainty and global sensitivity analysis, formulating Typical uncertain scenarios by orthogonal experiments (OE) and calculating the comprehensive robustness indicators. Results show that by employing the proposed workflow, the selected robust optimal solution not only proves to be robust but also leads to preferable performance enhancements. Compared with the reference mode, the energy efficiency has been improved by 33.2% to 49.4%, the discomfort hours have been reduced by 0.4% to 26.5%, and the robustness has been enhanced by 36.1%.

Robust envelope exchange platform for oncolytic measles virus

The use of oncolytic viruses (OV) to precisely target and eliminate tumors (‘virotherapy’) is a rapidly evolving therapeutic approach to treating cancer. A major obstacle in virotherapy, especially for systemic administration, is the host’s immune response towards the OV. In the case of measles virus (MeV), most individuals have been immunized against this agent leading to pre-existing neutralizing antibodies that can impair OV delivery to the tumor. These antibodies predominantly target the hemagglutinin (H) and fusion (F) envelope glycoproteins displayed at the particle’s surface. Here, we introduce a novel and versatile pseudotyping platform for rapid envelope exchange of oncolytic MeV that allows for engineering of chimeric viruses invulnerable to pre-existing anti-MeV antibodies. Using this system, we have successfully exchanged the MeV F and H proteins with the glycoprotein G of vesicular stomatitis virus (VSV) and the surface proteins of Newcastle disease virus (NDV) or canine distemper virus (CDV), all of which are not endemic in the general human population. While the MeV-VSV and MeV-NDV pseudotypes were non-functional, the MeV-CDV pseudotype was successfully propagated to high-titer virus stocks. This study describes the successful generation of a robust envelope exchange platform for oncolytic MeV while also highlighting its intricate pseudotyping tolerance.

The LCP Family Protein, Psr, Is Required for Cell Wall Integrity and Virulence in Streptococcus agalactiae.

A robust cell envelope is the first line of protection for an infecting pathogen when encountering the immune defense of its host. In Gram-positive organisms, LytR-CpsA-Psr (LCP) family proteins play a major role in the synthesis and assembly of the cell envelope. While these proteins could be considered for potential new drug targets, not enough is known about how they function to support the integrity of the cell wall. Streptococcus agalactiae (group B streptococcus or GBS) is known to encode at least three LCP family proteins, including CpsA, LytR (BrpA) and Psr. Using strains of GBS that have mutations in two of the three LCP proteins, we were able to determine a role for these proteins in GBS cell wall integrity. The results presented here demonstrate that the absence of Psr results in a decreased growth rate, decreased viability over time, inconsistent cocci morphology and diminished cell wall integrity, as well as an increased penicillin susceptibility, decreased capsule levels and attenuation in virulence in a zebrafish model of infectious disease. A strain that is missing two of the LCP family proteins, CpsA and Psr, exhibits an increase in these defective phenotypes, indicating that CpsA and Psr are partially redundant in function.

Identifying the ‘savanna’ signature in lacustrine sediments in northern Australia

This study reports palynological and geochemical results for modern and ancient sediments from 19 lakes on a rainfall gradient (784–1880 mm), across a range of savannas in Northern Australia. All proxies varied significantly across the range of sites examined, providing a robust envelope of values that can reliably be employed to identify a savanna signature in the sedimentary record. While the results indicate it is possible to identify a savanna, we found only three statistically significant relationships between any proxy measured in surface sediments and the major climate driver of savanna vegetation composition (rainfall amount). This is because edaphic factors play a dominant role in determining vegetation composition and also potentially because of the impact of land use change.Measures of fire determined by charcoal counting were positively correlated with geochemical measures of pyrogenic carbon abundance, suggesting both record a similar signal. While measures of fire incidence were not correlated with rainfall, there was a significant positive correlation between charcoal abundance and number of fires early in the dry season, suggesting that charcoal abundance is controlled more by the number/timing of fires than climate. There was also a significant correlation between the δ13C-value of pyrogenic carbon and tree:grass ratio derived from palynological indicators, indicating that the δ13C-value of PyC is a reliable indicator of savanna ‘woodiness’. Comparison of the carbon isotope composition of total organic carbon, PyC and n-alkanes between modern and Holocene sediments suggest that the savannas of the region have remained either similar in ‘woodiness’ or have thickened over the last millennia.

Cortical Correlates of Binaural Temporal Processing Deficits in Older Adults.

This study was designed to evaluate binaural temporal processing in young and older adults using a binaural masking level difference (BMLD) paradigm. Using behavioral and electrophysiological measures within the same listeners, a series of stimulus manipulations was used to evaluate the relative contribution of binaural temporal fine-structure and temporal envelope cues. We evaluated the hypotheses that age-related declines in the BMLD task would be more strongly associated with temporal fine-structure than envelope cues and that age-related declines in behavioral measures would be correlated with cortical auditory evoked potential (CAEP) measures. Thirty adults participated in the study, including 10 young normal-hearing, 10 older normal-hearing, and 10 older hearing-impaired adults with bilaterally symmetric, mild-to-moderate sensorineural hearing loss. Behavioral and CAEP thresholds were measured for diotic (So) and dichotic (Sπ) tonal signals presented in continuous diotic (No) narrowband noise (50-Hz wide) maskers. Temporal envelope cues were manipulated by using two different narrowband maskers; Gaussian noise (GN) with robust envelope fluctuations and low-noise noise (LNN) with minimal envelope fluctuations. The potential to use temporal fine-structure cues was controlled by varying the signal frequency (500 or 4000 Hz), thereby relying on the natural decline in phase-locking with increasing frequency. Behavioral and CAEP thresholds were similar across groups for diotic conditions, while the masking release in dichotic conditions was larger for younger than for older participants. Across all participants, BMLDs were larger for GN than LNN and for 500-Hz than for 4000-Hz conditions, where envelope and fine-structure cues were most salient, respectively. Specific age-related differences were demonstrated for 500-Hz dichotic conditions in GN and LNN, reflecting reduced binaural temporal fine-structure coding. No significant age effects were observed for 4000-Hz dichotic conditions, consistent with similar use of binaural temporal envelope cues across age in these conditions. For all groups, thresholds and derived BMLD values obtained using the behavioral and CAEP methods were strongly correlated, supporting the notion that CAEP measures may be useful as an objective index of age-related changes in binaural temporal processing. These results demonstrate an age-related decline in the processing of binaural temporal fine-structure cues with preserved temporal envelope coding that was similar with and without mild-to-moderate peripheral hearing loss. Such age-related changes can be reliably indexed by both behavioral and CAEP measures in young and older adults.

Binaural hearing in children using Gaussian enveloped and transposed tones.

Children who use bilateral cochlear implants (BiCIs) show significantly poorer sound localization skills than their normal hearing (NH) peers. This difference has been attributed, in part, to the fact that cochlear implants (CIs) do not faithfully transmit interaural time differences (ITDs) and interaural level differences (ILDs), which are known to be important cues for sound localization. Interestingly, little is known about binaural sensitivity in NH children, in particular, with stimuli that constrain acoustic cues in a manner representative of CI processing. In order to better understand and evaluate binaural hearing in children with BiCIs, the authors first undertook a study on binaural sensitivity in NH children ages 8-10, and in adults. Experiments evaluated sound discrimination and lateralization using ITD and ILD cues, for stimuli with robust envelope cues, but poor representation of temporal fine structure. Stimuli were spondaic words, Gaussian-enveloped tone pulse trains (100 pulse-per-second), and transposed tones. Results showed that discrimination thresholds in children were adult-like (15-389 μs for ITDs and 0.5-6.0 dB for ILDs). However, lateralization based on the same binaural cues showed higher variability than seen in adults. Results are discussed in the context of factors that may be responsible for poor representation of binaural cues in bilaterally implanted children.

Automated detection of sleep apnea and hypopnea events based on robust airflow envelope tracking in the presence of breathing artifacts.

The paper presents a new approach to detection of apnea/hypopnea events, in the presence of artifacts and breathing irregularities, from a single-channel airflow record. The proposed algorithm, based on a robust envelope detector, identifies segments of signal affected by a high amplitude modulation corresponding to apnea/hypopnea events. It is shown that a robust airflow envelope-free of breathing artifacts-improves effectiveness of the diagnostic process and allows one to localize the beginning and the end of each episode more accurately. The performance of the proposed approach, evaluated on 30 overnight polysomnographic recordings, was assessed using diagnostic measures such as accuracy, sensitivity, specificity, and Cohen's coefficient of agreement; the achieved levels were equal to 95%, 90%, 96%, and 0.82, respectively. The results suggest that the algorithm may be implemented successfully in portable monitoring devices, as well as in software-packages used in sleep laboratories for automated evaluation of sleep apnea/hypopnea syndrome.

Sound source localization: Clicks and click trains

Tino Trahiotis and Les Bernstein have provided valuable information about human listeners' ability to process interaural time differences in the envelopes of high-frequency carrier signals. These data have enriched models of binaural processing. In this paper, we explore sound source localization of click (100 microsecond transients) stimuli in the azimuth plane in the free field. We are especially interested in the sound source localization of click trains as they provide stimuli with robust envelope properties. We measured sound source localization accuracy for tones, single clicks, and click trains–unfiltered and filtered in low- and high-frequency regions. The filtering was performed to implicate the role of interaural time and level differences in sound source localization. These data involving clicks will be compared to recent findings from our laboratory involving sound source localization of broadband and filtered noise bursts as compared to sound source localization of umodulated and amplitude modulated tonal carriers. These data suggest that stimulus bandwidth is a major factor determining sound source localization accuracy, and that amplitude modulation plays a small role, at best, in determining sound source localization accuracy. The data involving click trains will help expand this database. [Research supported by the AFOSR.]

Availability of envelope interaural time-difference cues does not improve front/back localization of narrow-band high-frequency targets via head movement

Information about the front/rear location of a sound source is available in the relationship between the direction of head rotation and the direction of changes in interaural time and level differences (ITD and ILD). Our previous results show that such dynamic cues are highly effective for low-frequency stimuli, but minimally effective for narrowband high-frequency stimuli, in which, respectively, ITD and ILD cues are primarily available. In this study, we assessed the possible benefit for dynamic localization of providing more robust envelope ITD cues in high-frequency stimuli. Listeners judged the front/rear location of anechoic free-field stimuli presented over the central portion of a slow (~0.25 Hz), continual, 90-degree head oscillation. Stimuli were bursts of wideband (0.5–16 kHz), low-frequency (0.5–1 kHz), or high-frequency (6–6.5 kHz) random-phase noise or of raised-sine stimuli with exponent 2, modulation frequency 125 Hz, and bandwidth 6–6.5 kHz. Localization accuracy was high for wideband and lowpass stimuli but poor (and similar) for high-frequency noise and raised-sine stimuli, despite listeners' measured ITD JNDs for raised-sine stimuli being significantly lower than for high-frequency noise. The results suggest that neither veridical dynamic ILD nor ITD cues can overcome the erroneous spectral cue for front/back created by narrowband high-frequency stimuli.

A Robust Large Envelope Flight Controller Design Method Based on the Particle Swarm Optimization Algorithm

A robust flight control method based on the particle swarm optimization (PSO) algorithm is approved in this paper. Because of non-modeling dynamic character and parameter uncertainty are taken into consideration during the controller design process, the flight controller has strong robustness, excellent control performance and one robust controller could realize the large envelope flight control. In order to design the robust flight controller automatically and rapidly, the particle swarm optimization algorithm is used to select the weighting function. The simulation result shows that the weighting function could be designed automatically and rapidly, the flight controller has good performance and robustness.

Avaliação de processos MIG/MAG curto-circuito convencional e controlado para a soldagem de dutos de aço carbono em passe único

O desenvolvimento de fontes de soldagem com processos derivativos MIG/MAG com transferência por curto-circuito, também conhecidos como curto-circuito controlado, tem-se tornado uma tendência na busca de soldas de qualidade e produtividade, principalmente na união de dutos, pois acredita-se que, o controle da corrente permite melhorar a transferência metálica, proporcionando estabilidade ao processo de soldagem e a poça de fusão. Neste contexto, o objetivo deste trabalho é determinar envelope operacional e estabelecer vantagens e limitações operacionais dos processos MIG/MAG com transferência por curto-circuito convencional e derivativos (STT - SurfaceTensionTransfer, RMD - Regulated Metal Deposition e CMT - Cold Metal Transfer), para a união de dutos de aço carbono com diâmetro nominal de 2 ½"e parede fina com passe único, nas progressões ascendente e descendente. Para tal, optou-se por variar os parâmetros de regulagem de cada processo e a velocidade de alimentação do arame, além das técnicas de soldagem, procurando manter a mesma quantidade de material depositado por comprimento de solda. Os resultados encontrados mostraram que o curto-circuito convencional apresentou um envelope operacional constante para a progressão ascendente e para a descendente quanto ao número de ensaios. Ao passo que, o STT e o RMD apresentaram um maior envelope operacional na progressão descendente. Por outro lado, o CMT, com envelope operacional maior na ascendente, trabalha com valores de tensão de soldagem muito mais baixos, o que justifica o baixo aporte térmico do processo.

Auditory brainstem response hearing measurements in free-ranging bottlenose dolphins (Tursiops truncatus)

Bottlenose dolphins (Tursiops truncatus) rely on sound for communication, navigation, and foraging. Both natural and anthropogenic noise in the marine environment could mask the ability of wild dolphins to detect sounds, and chronic noise exposure could cause permanent hearing loss. The hearing abilities of a wild population of bottlenose dolphins in Sarasota Bay, FL are being investigated to determine whether they suffer hearing losses in comparison to animals living in quieter environments. This study is the first to measure the hearing sensitivity of a large population of wild dolphins that are exposed to significant levels of noise. Data on hearing sensitivities at frequencies used for acoustic communication (5–20 kHz) and echolocation (20–100 kHz) are reported. Hearing sensitivity was measured in the field using the non-invasive auditory brainstem response (ABR) procedure. ABR responses were evoked by the presentation of amplitude-modulated (AM) tones (carrier frequencies of 5, 10, 20, 30, 60, and 80 kHz) through a jawphone. The tones were modulated at 600 Hz, which elicited a robust envelope following response. A rapid ABR procedure was employed so that an entire audiogram could be obtained in approximately 30 min. This study also provides baseline data for longitudinal hearing studies in known individuals.

Envelope-constrained H/sub ∞/ FIR filter design

In this paper, we are concerned with the design of a finite-impulse response (FIR) filter, such that the H/sub /spl infin// norm of the filtering error-transfer function is minimized subject to the constraint that the filter output with a given input to the signal system is contained or bounded in a prescribed envelope. The filter design problem is formulated as a standard optimization problem with linear matrix inequalities (LMIs) constraint. Furthermore, by relaxing the H/sub /spl infin// norm constraint, we propose a robust envelope constrained FIR design algorithm based on the LMI approach.