Circular Dichroism Spectral Similarity Plots to Extend Validation and Correction to All Measured Wavelengths

Interlaboratory comparisons of circular dichroism (CD) spectra are useful for developing confidence in the measurements associated with optically active molecules. These measurements also help define the higher-order (secondary and tertiary) structure of biopolymers. Unfortunately, the extent of the validity of these measurements has been unclear. In this work, a method is described to extend CD validation over the entire observed wavelength range using what will be called spectral similarity plots. The method involves plotting, wavelength by wavelength, all measured spectral intensities of a sample at one concentration against the intensity values of the same material at a different concentration or pathlength. These spectral similarity plots validate the instrument in terms of spectral shape and whether the shape is shifted in intensity and/or in wavelength. This comparison tests the linearity of instrument’s signal, the balance of its left and right polarizations, its wavelengths, and its spectral intensity scales. When the process is applied to materials with accepted and archived intensity values, the method can be linked to older single-wavelength and double-wavelength calibration techniques. Further, spectral similarity testing of CD spectra from samples with different concentrations run in different labs suggests that improved interlaboratory validation of CD data is possible. Since a database of archival CD measurements is available online, spectral similarity comparisons could possibly provide the ability to compare linearity, polarization balance, wavelength, and spectral intensity between all current CD instruments. If the preliminary results published here prove robust and transferable, then comparisons of full-wavelength range spectra to archived data using spectral similarity plots should become part of the standard process to validate and calibrate the performance of CD instruments.

Magnetometer heading estimation through online calibration for land navigation applications

For land navigation applications, the integration of the magnetometer with the combination of MEMS-INS and the Global Navigation Satellite System (GNSS) give excellent results. During land navigation applications, the magnetometer’s heading can also be used during the GNSS outages. The calibration of the magnetometer is indispensable to calculate its accurate heading. There exist several methods for magnetometer calibration. Some are offline and some are online calibration techniques. In this paper, a calibration method is proposed to estimate the magnetometer’s parameters through online calibration in run time. In this method, the reference magnetic field is calculated from the World Magnetic Model (WMM-2020). Moreover, reference roll, pitch and heading are provided from some other sources such as GNSS, Attitude Heading Reference System (AHRS), or reference INS. For different roll and pitch sectors, calibration parameters are estimated and stored. These parameters are used for magnetometer online calibration during the field testing. Both the headings obtained by the online calibration and conventional lab calibrations are analysed. Furthermore, the heading estimated through the online calibration is autonomous and fast. Subsequently, there is no user involvement in this online calibration technique and no specific movements to the device are provided. The heading obtained by novel technique is as accurate as obtained by conventional offline lab calibration.

An Exploration of Building Energy Model (BEM) Calibration in New Zealand

<p>This study explored the use of Building Energy Modelling (BEM) and BEM calibration techniques for existing buildings as currently employed in New Zealand Industry. Research on the use of BEM for existing building energy efficiency retrofits has increased dramatically over the past few decades. However, this use of BEM has been criticised for inaccurate and unbelievable results. These are often the result of not closely matching the building being modelled due to uncertainties around model inputs and modeller assumptions. As a result, researchers have responded by developing techniques to ‘calibrate’ models by comparing the simulated building with the actual building energy use thus providing quality assurance. However, many of these techniques are difficult, esoteric, convoluted or impractical for industry professionals. This research explored if a simple calibration technique developed at Victoria University of Wellington by Dr. Shaan Cory would meet the needs of industry practitioners. The technique was turned into a usable tool and student trialled to prepare it for industry assessment. Four BEM experts were then interviewed in a series of individual interviews and workshops trialling the use of the technique. The research concluded that the use of BEM is limited in New Zealand due to a perceived Industry value gap – building owners are not aware of the benefits of modelling whole-building retrofits. This leads to reduced uptake of calibration techniques from industry resulting in a credibility gap, where the modeller themselves may not be confident of their own BEMs. This is due, in part, to a lack of industry quality assurance guidelines, usable calibration tools, and certainty around model inputs. The adoption of the streamlined Cory method would be of significant benefit to practitioners. However, it was identified that it did not solve all issues relating to uncertainty estimation.</p>

An Exploration of Building Energy Model (BEM) Calibration in New Zealand

<p>This study explored the use of Building Energy Modelling (BEM) and BEM calibration techniques for existing buildings as currently employed in New Zealand Industry. Research on the use of BEM for existing building energy efficiency retrofits has increased dramatically over the past few decades. However, this use of BEM has been criticised for inaccurate and unbelievable results. These are often the result of not closely matching the building being modelled due to uncertainties around model inputs and modeller assumptions. As a result, researchers have responded by developing techniques to ‘calibrate’ models by comparing the simulated building with the actual building energy use thus providing quality assurance. However, many of these techniques are difficult, esoteric, convoluted or impractical for industry professionals. This research explored if a simple calibration technique developed at Victoria University of Wellington by Dr. Shaan Cory would meet the needs of industry practitioners. The technique was turned into a usable tool and student trialled to prepare it for industry assessment. Four BEM experts were then interviewed in a series of individual interviews and workshops trialling the use of the technique. The research concluded that the use of BEM is limited in New Zealand due to a perceived Industry value gap – building owners are not aware of the benefits of modelling whole-building retrofits. This leads to reduced uptake of calibration techniques from industry resulting in a credibility gap, where the modeller themselves may not be confident of their own BEMs. This is due, in part, to a lack of industry quality assurance guidelines, usable calibration tools, and certainty around model inputs. The adoption of the streamlined Cory method would be of significant benefit to practitioners. However, it was identified that it did not solve all issues relating to uncertainty estimation.</p>

Black-Box Diagnosis and Calibration on GAN Intra-Mode Collapse: A Pilot Study

Generative adversarial networks (GANs) nowadays are capable of producing images of incredible realism. Two concerns raised are whether the state-of-the-art GAN’s learned distribution still suffers from mode collapse and what to do if so. Existing diversity tests of samples from GANs are usually conducted qualitatively on a small scale and/or depend on the access to original training data as well as the trained model parameters. This article explores GAN intra-mode collapse and calibrates that in a novel black-box setting: access to neither training data nor the trained model parameters is assumed. The new setting is practically demanded yet rarely explored and significantly more challenging. As a first stab, we devise a set of statistical tools based on sampling that can visualize, quantify, and rectify intra-mode collapse . We demonstrate the effectiveness of our proposed diagnosis and calibration techniques, via extensive simulations and experiments, on unconditional GAN image generation (e.g., face and vehicle). Our study reveals that the intra-mode collapse is still a prevailing problem in state-of-the-art GANs and the mode collapse is diagnosable and calibratable in black-box settings. Our codes are available at https://github.com/VITA-Group/BlackBoxGANCollapse .

Multi-station calibration strategy for evaluation and sensitivity analysis of the snowmelt runoff model using MODIS satellite images

In this study, the snowmelt runoff model (SRM) was employed to estimate the effect of snow on the surface flow of Aji-Chay basin, northwest Iran. Two calibration techniques were adopted to enhance the calibration. The multi-station calibration (MSC) and single-station calibration (SSC) strategies applied to investigate their effects on the modeling accuracy. The runoff coefficients (cs and cr) were selected as calibration parameters because of their uncertainty in such an extended basin. To determine the most substantial input of the model which is the snow-covered area (SCA) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor imagery, MOD10A2 images were collected with spatial and temporal resolutions of 500 meters and 8 days, respectively. The results show an average of 15% improvement in the model performance in the MSC strategy from the data period of 2008–2012. Also, an appropriate agreement with physical characteristics of the study area could be seen for the calibration parameters. The contribution of snowmelt in the river flow reaches its peak in April and May, then with increasing temperature, the contribution decreased gradually. Furthermore, analysis of parameters indicates that the SRM is sensitive to recession coefficient and runoff coefficients.

Localization Of A Mobile Fastening Robot

<div>The goal of this research is to develop a localization system for a mobile fastening robot using a camera and ultrasonic sensors. Localization is performed by using triangulation methods on three target fastener heads. Camera calibration parameters are determined and used to obtain a corrected image on which a Circular Hough Transform algorithm is used to determine the location of the three target fastener heads relative to the camera. The distance to the fastener heads is determined using readings from two ultrasonic sensors. A Kalman Filter is developed and used to reduce the noise of the ultrasonic sensor readings. In addition to filtering, calibration techniques are used to correct the readings of the final localization system. Testing of the complete system is done using a coordinate measuring machine. </div>

Localization Of A Mobile Fastening Robot

<div>The goal of this research is to develop a localization system for a mobile fastening robot using a camera and ultrasonic sensors. Localization is performed by using triangulation methods on three target fastener heads. Camera calibration parameters are determined and used to obtain a corrected image on which a Circular Hough Transform algorithm is used to determine the location of the three target fastener heads relative to the camera. The distance to the fastener heads is determined using readings from two ultrasonic sensors. A Kalman Filter is developed and used to reduce the noise of the ultrasonic sensor readings. In addition to filtering, calibration techniques are used to correct the readings of the final localization system. Testing of the complete system is done using a coordinate measuring machine. </div>