Amount Of Drift Research Articles

Differential Assessment of Black-Box AI Agents

Much of the research on learning symbolic models of AI agents focuses on agents with stationary models. This assumption fails to hold in settings where the agent's capabilities may change as a result of learning, adaptation, or other post-deployment modifications. Efficient assessment of agents in such settings is critical for learning the true capabilities of an AI system and for ensuring its safe usage. In this work, we propose a novel approach to differentially assess black-box AI agents that have drifted from their previously known models. As a starting point, we consider the fully observable and deterministic setting. We leverage sparse observations of the drifted agent's current behavior and knowledge of its initial model to generate an active querying policy that selectively queries the agent and computes an updated model of its functionality. Empirical evaluation shows that our approach is much more efficient than re-learning the agent model from scratch. We also show that the cost of differential assessment using our method is proportional to the amount of drift in the agent's functionality.

Drift Potential Characteristics of a Flat Fan Nozzle: A Numerical and Experimental Study

This study explores the drift potential characteristics of a flat fan nozzle. The atomization and drift characteristics of fan-shaped pressure nozzles were studied at a spraying height of 0.6 m and a lateral wind speed of 0–6 m/s through a combination of computational fluid dynamics (CFD) analyses and wind tunnel experiments. The nozzle Lu 120-03 had a spraying pressure of 0.3 MPa. The results show that as the wind speed varies from 0 m/s to 6 m/s, the spray droplet spectrum also changes, and the droplet volume medium diameter increases. The cumulative droplet ratio and droplet spectral width of M oscillate within certain ranges. The amount of spray drift increases at higher wind speeds. The concentration of droplet deposition on the bottom of the wind tunnel gradually spreads downward in the wind direction. The determination coefficient R2 of the straight-line fitting of the drift characteristics is 0.982, which is highly consistent with the CFD simulation results. A CFD simulation-assisted wind tunnel test method, which is more convenient and repeatable than traditional field tests, is proposed to analyze the droplet spectrum and drift of Lechler series nozzles. The program can accurately simulate the actual drift and provide theoretical and data support for the optimization of atomization and drift characteristics of several types of flat fan nozzles under different spraying pressures and crosswinds in practical applications.

On-line drift compensation for continuous monitoring with arrays of cross-sensitive chemical sensors

Long-term application of chemical sensor arrays for continuous monitoring is challenging as a result of sensor drift. Drift correction often requires periodic recalibration, which may not be feasible for sensors deeply embedded and deployed for uninterrupted continuous monitoring. In this paper, we propose a multi-calibration ensemble approach to compensate for sensor drift in such applications. Our method uses past sensor measurements for which ground-truth is available, and treats them as “pseudo-calibration” samples. With these, it builds a regression model to predict the concentration of target analytes by combining (1) the current sensor measurements and (2) the history of prior pseudo-calibration samples. We evaluate the efficacy of the proposed model using three different regression techniques, partial least squares, extreme gradient boosting, and neural networks, and compare it against two baselines: regression models that do not use the pseudo-calibration samples, and a state-of-the-art drift-correction technique. We evaluated these models on an experimental dataset from a bioprocess control application, and characterize them as a function of cross-sensitivity in the sensor array and amount of drift through computer simulations. The proposed approach outperforms both baselines on the experimental dataset, and under all simulation conditions, achieving significantly lower normalized root mean square errors in the prediction of target variables. These results hold for the three regression models used, which indicates that the proposed approach is agnostic to the underlying regression model.

Spray drift-based pesticide residues on untreated edible crops grown near agricultural areas

We aimed to quantify spray drift-based exposure of fruits and vegetables grown in gardens or allotments next to agricultural areas to plant protection products (PPP). The amount of spray drift transported into gardens during the treatment of tall growing crops or field crops was simulated. Two different test systems in an outdoor wind tunnel were used, approximating conditions for the application to both crop types. For the experiments, strawberries, tomatoes and lettuce were used representing non-target food crops in gardens. After spraying, distance-related residues of the tracer pyranine were measured on the three food crops positioned 1–15 m downwind in the non-target area. Additionally, petri dishes were placed in front of the food crops to measure the ground deposition concurrently. For both scenarios, good correlation of residues on the non-target food crops and the ground deposition was found (linear regression model, R2 = 0.88–0.97). But unlike the field crops scenario, the experimental setup of the tall growing crops shows large deviations from the field situation, not allowing the transfer of the results to the field situation. The results of the wind tunnel experiments and of field trials on ground deposition were used to estimate the amount of PPP residues on food crops cultivated near agricultural fields. For example, application of a pesticide (1.3 kg active ingredient per ha−1) to field crops was estimated to result in residue levels of 0.39 mg kg−1 on lettuce, 0.32 mg kg−1 on strawberries, and 0.06 mg kg−1 on tomatoes cultivated 5 m from the field, thus indicating an exceedance of the default maximum residue level (MRL) (0.01 mg kg−1). Therefore, further in-depth studies are required to broaden the range of non-target crops and to refine the tall growing crop scenario to allow estimations of spray drift-based residues.

Seismic Analysis of Multi Storey Buildings With and Without Shear-Walls

A structure in its design life period is subjected to a number of earthquakes of various intensities from small to medium and large. The work of a structural engineer is to come up with a design that will be able to resist the impact of earthquake without collapse. Earthquake resisting members like shear-walls are ductile in nature and they exhibit enough resistance to face the seismic forces and reduce the amount of drifts and displacements. In this study, an under 50m category building (twelve storey, G+11, total height 36m) and a 50-100 m category building (twenty-eight storey, G+27, total height 84m) are considered with and without shear-wall configuration for seismic analysis. Both static and dynamic analysis are applied to the structures using ETABs software. Difference in results for drifts and displacements are studied in this investigation.

Derivation of Kinematic Equations Based on Full-Scale Racking Tests for Seismic Performance Evaluation of Unitized Four-Sided Structural Sealant Glazing Curtain Wall Systems

Curtain wall glazing systems are a major part of a building due to the multiple roles they have, including occupant protection against environmental effects and the transfer of loads to the structural system. From a structural perspective, limited analytical guidelines and methods exist to aid designers in their determination of the curtain wall performance without extensive simulation or laboratory testing. This study takes experimental data from full-scale, “unitized”, four-sided structural sealant glazing (4SSG) curtain wall system mockups featuring a re-entrant corner subjected to cyclic racking displacements in accordance with the American Architectural Manufacturers Association AAMA 501.6 protocol to derive and establish equations that predict the relative displacements of the glass relative to the glazing frame, based on the amount of inter-story drift. Through derivation and testing, sealant cohesive failure and glass cracking were identified as limit states and corresponding drift levels were determined to control many of the equations. Displacements from the newly derived equations were correlated to the effective shear strain value experienced by the structural silicone in the mockup concurrently with the curtain wall’s drift capacity. This paper provides detailed derivation of the kinematic equations for possible use by glazing design professionals. Such equations can help designers to more easily predict the drifts that cause damage to such systems by manual calculations without the need for expensive mockup testing or time-intensive computer models.

Experimental Validation of Detachable Links for Eccentrically Braced Frames

AbstractEccentrically braced frames (EBFs) subjected to seismic actions dissipate energy through yielding of link members. Other members of the framing are on the other hand designed to remain mainly elastic during a seismic event. The framing can be reused after an earthquake if the link members can be replaced. In line with this, the last decade has witnessed development of replaceable links. However, most of the proposed details are not well suited for replacement under residual drift conditions. Consequently, this paper presents details of an experimental validation of a detachable link concept where a splice connection is introduced at the mid‐length of the link to facilitate replacement under residual frame drift. The concept was studied by conducting six nearly full scale EBF tests under quasi‐static cyclic loading. Different splice details employing bolted connections with vertical slotted or site drilled holes and welded connections were developed. The link length ratio, type of mid‐splice connection and the amount of residual drift were considered as the variables of the testing program. The specimens were subjected to the loading protocol recommended in AISC Seismic Provisions for Structural Steel Buildings (AISC‐341). The experimental results suggested that the detachable links with the proposed connection details can satisfy the link rotation capacity limits of AISC‐341. The detachable links performed similar to conventional links while their replaceability under residual drift was demonstrated.

D-shaped surface plasmon resonance biosensor based on [formula omitted] in terahertz band

We propose a terahertz surface plasmon biosensor based on MoS2 for detecting blood components. The change of the thickness of MoS2 has a great influence on the amount of resonance peak drift. The ultra-high wavelength sensitivity and resolution ratio of the biosensor are 715.59 μm/RIU and 1.40 × 10−7 RIU, respectively. When the overall structure of the sensor changes by ±0.4%, the maximum relative error of the resonance frequency is 1.3699%, and the maximum relative error of the peak loss is 1.5327%, which are all within a reasonable range and will not affect the sensor’ performance.

Investigating the Effect of Viscous Yield Dampers on Concrete Structure Performance

Viscous dampers are one of the most effective devices in the energy consumption of the buildings. The passive hybrid system progressive applications cause each of the dampers to compensate for the weakness of the other system, thus increasing the efficiency of passive control of the structure. Speed-based viscous dampers will adjust the amount of depreciation force based on the acceleration and velocity entering the system. On the other hand, displacement-based surge dampers adjust the amount of depreciation force based on the displacement required. Therefore, considering the different performances of these two dampers, the effect of using both of them in one structure can be investigated. In this study, by combining these two dampers, the seismic behavior of concrete structures has been evaluated. To study them, 5- and 10-story structures have been designed using FE method and have been subjected to earthquake records. Historical analysis shows that the use of hybrid dampers reduces the amount of seismic input force to the structure and also the amount of floor drift is reduced due to the use of dampers and also the capacity of structures for these structures is increased. The results of the study show that the presence of dampers in the structure increases energy absorption and improves performance in the structure.

Application of Carbon-Based Nanomaterials in Acid-Base Sensors

At present, long-term flight of carrier-based aircraft and other naval aviation equipment in high-salt, high-humidity environments will be subject to various environmental corrosion. The traditional means of monitoring aircraft corrosion is to seal water and prevent periodic inspections. The two monitoring methods are inefficient, and it is not easy to find the corrosion condition in the early stage of corrosion. When the corrosion really occurs, it will seriously threaten the safe flight of the aircraft and the safety of the pilot. Therefore, there is a need to develop an on-line monitoring sensor device for aircraft corrosion conditions to carry out real-time monitoring of aircraft acid-base corrosion (pH) conditions in high-salt, high-humidity marine environments. This paper mainly studies the application of carbon-based nanomaterials in acid-base sensors. In this paper, the acid-base sensor potential values at the same pH value are changed back and forth. In the initial state, the acid-base sensor potential values corresponding to pH = 3 are 385, 386, 379, and 392 mV, respectively. After 1500 s, the potential values of the acid-base sensor were 384, 383, 377, and 390 mV, and the three-phase hysteresis potential of the acid-base sensor was 1, 3, 2, and 2 mV, indicating that the acid-base sensor produced a small hysteresis potential. However, the amount of sensor drift is within a controllable range, and the response time of the acid-base sensor is relatively short regardless of the solution with different pH values added dropwise from acid to alkali or from alkali to acid. Therefore, the acid-base sensor has good hysteresis and recyclability.

Photothermal Optical Beam Steering Using Large Deformation Multi-Layer Thin Film Structures.

Photothermal actuation of microstructures remains an active area of research for microsystems that demand electrically isolated, remote, on-chip manipulation. In this study, large-deformation structures constructed from thin films traditional to microsystems were explored through both simulation and experiment as a rudimentary means to both steer and shape an incident light beam through photothermal actuation. A series of unit step infrared laser exposures were applied at increasing power levels to both uniformly symmetric and deliberately asymmetric absorptive structures with the intent of characterizing the photothermal tilt response. The results indicate that a small angle (<4° at ~74 W/cm2) mechanical tilt can be instantiated through central placement of an infrared beam, although directional control appears highly sensitive to initial beam placement. Greater responsivity (up to ~9° mechanical tilt at ~54 W/cm2) and gross directional control was demonstrated with an asymmetrical absorptive design, although this response was accompanied by a large amount (~5–10°) of mechanical tilt burn-in and drift. Rigorous device cycling remains to be explored, but the results suggest that these structures, and those similar in construction, can be further matured to achieve controllable photoactuation suitable for optical beam control or other applications.

Spinal Cord Drift Following Laminoplasty Versus Laminectomy and Fusion for Cervical Spondylotic Myelopathy.

Cervical laminoplasty and laminectomy and fusion (LF) are posterior-based surgical techniques for the surgical treatment of cervical spondylotic myelopathy (CSM). Interestingly, the comparative amount of spinal cord drift obtained from these procedures has not been extensively described. The purpose of this study is to compare spinal cord drift between cervical laminoplasty and LF in patients with CSM. The laminoplasty group consisted of 22 patients, and the LF group consisted of 44 patients. Preoperative and postoperative alignment was measured using the Cobb angle (C2-C7). Spinal cord position was measured on axial T2-magnetic resonance imaging of the cervical spine preoperatively and postoperatively. Spinal cord drift was quantified by subtracting preoperative values from postoperative values. Functional improvement was assessed using the modified Japanese Orthopaedic Association (mJOA) score. Mean spinal cord drift was higher following LF compared to laminoplasty (2.70 vs 1.71 mm, P < .01). Using logistic regression analysis, there was no correlation between sagittal alignment and spinal cord drift. Both groups showed an improvement in mJOA scores postoperatively compared to their preoperative values (laminoplasty, +2.0, P = .012; LF, +2.4, P < .01). However, there was no difference in mJOA score improvement postoperatively between both groups (P = .482). This study demonstrates that patients who had LF for CSM achieved more spinal cord drift postoperatively compared to those who had laminoplasty. However, the increased drift did not translate into superior functional outcome as measured by the mJOA score. 3. Spinal cord drift following LF may differ from laminoplasty in patients undergoing surgery for CSM. This finding should be considered when assessing CSM patients for surgical intervention.

Reducing Spray Drift and Increasing Spreading Effect of the Thifluzamide Through the Use of Adjuvants and Nozzles

Spray drift, as a practical issue during Unmanned Aerial Vehicle (UAV) spraying, has a negative impact on the environment, and the use of air-induction nozzles or anti-drift adjuvants are the most common recommendations for reducing drift. To screen the adjuvants for favourable atomization performance and anti-drift effect, we evaluated the spray atomization performance of different adjuvants by the droplet size measurement system. From the wind tunnel results, we commented on the relationship among the atomization performance, drift distance and drift deposition, and determined the drift percentage of different nozzles and the surface tension of liquids with different adjuvants. The results showed that the addition of adjuvants would modify the distribution span S, ΦVol&lt;150μm and the volume medium diameter D50; ΦVol&lt;150μm and D50 of the Maifei treatment decreased and increased the most of all the treatments. There were negative correlations between the drift distance, D50 and percentage of drift amount. The adjuvants Maifei and the nozzle IDK120-015 significantly decreased the drift deposition amount. And the anti-drift effect of nozzle IDK120-015 plus Maifei was significantly stronger than that of other nozzles or adjuvants. In addition, the addition of adjuvants could significantly decrease the surface tension, especially for Maifei. These results suggest that the addition of Maifei is an effective way to reduce the spray drift for all nozzle types and lessen the surface tension. These data help to provide a theoretical basis for selecting suitable nozzles and adjuvants for plant protection UAVs.

Experimental Constraints on Homogenization of Plagioclase-Hosted Melt Inclusions From Plagioclase Ultraphyric Basalts

Study of melt inclusions (MIs) is a commonly applied method for defining the composition of magmas present at depth prior to mixing, fractionation, and degassing. Our ability to use data from MIs is complicated by post-entrapment processes (PEP) that can modify their composition during transport and eruption. Many of the PEP can be reversed by heating the MIs to temperatures near those at which the MI and its host were formed. However, the process of reversing PEP by homogenization may introduce changes in MI compositions, making interpretation difficult. We present a series of low and high pressure homogenization experiments on plagioclase-hosted MIs from Plagioclase Ultraphyric Basalts (PUBs) designed to develop a methodology for recovering the composition at the time of entrapment of plagioclase-hosted MIs. These experiments included low pressure (1 bar) homogenization experiments conducted as a time series for 30 min, 4 h, 1 day, 4 days, and 8 days), and at 7.5 kbar for 2 and 4 days. The 7.5 kbar pressure used for the high pressure experiments was based on the CO2-based entrapment pressures determined from MI from this sample. Experiments run at low pressure and run times of 4 and 8 days exhibited compositional drift, most notably in the form of increasing MgO in MIs. This drift was not observed at 7.5 kbars or for the shorter run time 1 atm experiments. These results are consistent with a model where drift in composition with time is caused by crystal relaxation driven by the high internal pressure within the MI (the pressure at which the MI formed), together with the lower confining pressure during homogenization (1 bar). Therefore, MI homogenization will produce the least amount of drift if runs are made for short time periods (∼30 min) or at the pressure of entrapment.

Is the absolute scaling model the basis for the 9-point hedonic scale? Evidence from Poulton’s Stimulus Range Equalizing Bias

Besides confirming earlier work, this study provided evidence for the theoretical position that consumers use cognitive strategies based on an absolute behavioral model, for the traditional verbal version of the 9-point hedonic scale. This is opposed to the relative model, which is appropriate for the less frequently used purely numerical and unstructured version of the 9-point hedonic scale. After establishing a constant rank order of liking for six chocolate stimuli, consumers rated the chocolates using the traditional verbal version and an unstructured numerical version of the 9-point hedonic scale. The numerical data produced by each scale were different and incompatible for significant majorities of consumers, after correction for their unimodal and bimodal designs. This occurred with both rank-rating and serial monadic protocols. This was confirmed using pattern change scores, a parametric measure of the discrepancy between ‘words only’ and ‘numbers only’ scaling responses. It also checked for ‘scaling drift’, inconsistency in scale use. The fact that numerical scales based on the relative model are prone to Poulton’s Stimulus Range Equalizing Bias and that scales based on an absolute model are not, was used to investigate the model for the traditional verbal 9-point hedonic scale. The verbal scale was much less prone to Poulton’s bias than the numerical scale but it was still partially prone. Poulton’s bias had demonstrated that the model for the traditional verbal 9-point scale was different from the relative model for a purely numerical scale. Yet, it had failed to demonstrate that the different model was the absolute model. It had partial absolute and partial relative properties. Descriptions of the nature of the model are discussed. Compared with rank-rating, the effects of high memory load, which is systemic for the serial monadic protocol, was evidenced by higher error rates due to forgetting, higher amounts of scaling drift and discrepancies between the order of ranked and rated data.

Atomic-Resolution Imaging of Fast Nanoscale Dynamics with Bright Microsecond Electron Pulses.

Atomic-resolution electron microscopy is a crucial tool to elucidate the structure of matter. Recently, fast electron cameras have added the time domain to high-resolution imaging, allowing static images to be acquired as movies from which sample drift can later be removed computationally and enabling real-time observations of atomic-scale dynamics on the millisecond time scale. Even higher time resolution can be achieved with short electron pulses, yet their potential for atomic-resolution imaging remains unexplored. Here, we generate high-brightness microsecond electron pulses from a Schottky emitter whose current we briefly drive to near its limit. We demonstrate that drift-corrected imaging with such pulses can achieve atomic resolution in the presence of much larger amounts of drift than with a continuous electron beam. Moreover, such pulses enable atomic-resolution observations on the microsecond time scale, which we employ to elucidate the crystallization pathways of individual metal nanoparticles as well as the high-temperature transformation of perovskite nanocrystals.

Prevention of Microsphere Blockage in Catheter Tubes Using Convex Air Bubbles.

This paper presents a novel method to prevent blockages by embolic microspheres in catheter channels by using convex air bubbles attached to the channels’ inner wall surface. The clogging by microspheres can occur by the arching of the microspheres in the catheter. A few studies have been done on reducing the blockage, but their methods are not suitable for use with embolic catheters. In this study, straight catheter channels were fabricated. They had cavities to form convex air bubbles; additionally, a straight channel without the cavities was designed for comparison. Blockage was observed in the straight channel without the cavities, and the blockage arching angle was measured to be 70°, while no blockage occurred in the cavity channel with air bubbles, even at a geometrical arching angle of 85°. The convex air bubbles have an important role in preventing blockages by microspheres. The slip effect on the air bubble surface and the centrifugal effect make the microspheres drift away from the channel wall. It was observed that as the size of the cavity was increased, the drift distance became larger. Additionally, as more convex air bubbles were formed, the amount of early drift to the center increased. It will be advantageous to design a catheter with large cavities that have a small interval between them.

Evolution of an Asteroid Family under YORP, Yarkovsky, and Collisions

Abstract Any population of asteroids, like asteroid families, will disperse in semimajor axis due to the Yarkovsky effect. The amount of drift is modulated by the asteroid spin state evolution, which determines the balance between the diurnal and seasonal Yarkovsky forces. The asteroid’s spin state is, in turn, controlled in part by the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect. The otherwise smooth evolution of an asteroid can be abruptly altered by collisions, which can cause impulsive changes in the spin state and can move the asteroid onto a different YORP track. In addition, collisions may also alter the YORP parameters by changing the superficial features and overall shape of the asteroid. Thus, the coupling between YORP and Yarkovsky is also strongly affected by the impact history of each body. To investigate this coupling, we developed a statistical code modeling the time evolution of semimajor axis under YORP–Yarkovsky coupling. It includes the contributions of NYORP (normal YORP), TYORP (tangential YORP), and collisions whose effects are deterministically calculated and not added in a statistical way. We find that both collisions and TYORP increase the dispersion of a family in semimajor axis by making the spin axis evolution less smooth and regular. We show that the evolution of a family’s structure with time is complex and collisions randomize the YORP evolution. In our test families, we do not observe the formation of a “YORP-eye” in the semimajor axis versus diameter distribution, even after a long period of time. If present, the “YORP-eye” might be a relic of an initial ejection velocity pattern of the collisional fragments.

Morpho-Butterfly Inspired Lamella-based Optical Sensors for Measuring Percent Level Concentrations of H2 and CO with Au and CeO2

Morpho-Butterfly inspired lamella structures were fabricated to make a multivariable optical sensor for measuring percent level concentrations of H2 and CO in a high temperature, zero-O2 environment. The SiO2 and Si3N4 3D structures were covered with gold nanoparticles (AuNPs) and cerium IV dioxide (CeO2) and exposed to varying concentrations of H2 and CO at 300°C. Experiments with AuNP sizes with an average diameter of 11 ± 3 nm and 3 ± 0.5 nm (larger and small AuNPs, respectively) showed that the larger AuNPs had a stronger response to the same concentrations of H2 and CO with less CO saturation and baseline drift. Further testing in the presence of 1% hydrocarbons (HCs) as an interfering gas showed excellent response to up to 17% H2 and CO in a zero-O2 environment with changes in reflected intensity of -13.1 ± 0.4% for H2 and -5.8 ± 0.3% for CO. The presence of HCs did not induce any baseline drift, with the total amount of drift being less than 0.5% over 13 hours of testing at 300°C.

Field evaluation of spray drift and environmental impact using an agricultural unmanned aerial vehicle (UAV) sprayer

Unmanned Aerial Vehicle (UAV) applications at low-volume using fine and very fine size droplets have been adopted in several commercial spray scenarios allowing water-saving and high-efficiency operation in delivery of pesticides. However, spray drift associated with UAV applications, especially for fine droplets generated from spinning disk nozzles, has not been fully understood, raising environmental and regulatory concerns. The objectives of this study were to compare the drift potential of three different volume median diameter (VMD, or Dv0.5) of 100, 150 and 200 μm from a commercial quadcopter equipped with centrifugal nozzles exposed to different wind speeds under field conditions. Prior to field test, the droplet size of the centrifugal nozzle was measured by a laser-diffraction particle-size analyzer. The results showed that the relationship between rotation speed and Dv0.5 agrees with the negative power function. Field tests found that the deposition at 12 m downwind direction decreased by an order of magnitude compared with the average deposition within the in-swath zone. The deposition of almost all the treatments at 50 m downwind is lower than the detection limits of 0.0002 μL/cm2. Based on the results from this study, the drift distance of this specific very popular UAV model is much less than that of manned aerial applicators. Based on the predicted equation (R2 = 0.83), the detected drift amount increased with increasing wind speed and decreasing Dv0.5. This work provides basic information to quantify the effect of wind speeds and droplet sizes on UAV spray drift potential which supports on-going regulatory guideline development for spray buffer zone and drift risk assessment protocols.