Computationally Efficient Noninvasive Cardiac Activation Time Imaging

2005 ◽  
Vol 44 (05) ◽  
pp. 674-686 ◽  
Author(s):  
B. Pfeifer ◽  
M. Seger ◽  
C. Hintermüller ◽  
F. Hanser ◽  
R. Modre ◽  
...  
Keyword(s):  
Regularization Parameter ◽  
Computation Time ◽  
Computationally Efficient ◽  
Activation Time ◽  
Ablation Therapy ◽  
Order Of Magnitude ◽  
Regularization Strategy ◽  
Comparable Quality ◽  
Activation Sequence

Summary Objective: The computer model-based computation of the cardiac activation sequence in humans has been recently subject of successful clinical validation. This method is of potential interest for guiding ablation therapy of arrhythmogenic substrates. However, computation times of almost an hour are unattractive in a clinical setting. Thus, the objective is the development of a method which performs the computation in a few minutes run time. Methods: The computationally most expensive part is the product of the lead field matrix with a matrix containing the source pattern on the cardiac surface. The particular biophysical properties of both matrices are used for speeding up this operation by more than an order of magnitude. A conjugate gradient optimizer was developed using C++ for computing the activation map. Results: The software was tested on synthetic and clinical data. The increase in speed with respect to the previously used Fortran 77 implementation was a factor of 30 at a comparable quality of the results. As an additional finding the coupled regularization strategy, originally introduced for saving computation time, also reduced the sensitivity of the method to the choice of the regularization parameter. Conclusions: As it was shown for data from a WPW-patient the developed software can deliver diagnostically valuable information at a much shorter span of time than current clinical routine methods. Its main application could be the localization of focal arrhythmogenic substrates.

Efficient Computing in Image Processing and DSPs with ASIP Based Multiplier

2019 ◽  
Vol 13 (2) ◽  
pp. 174-180
Author(s):  
Poonam Sharma ◽  
Ashwani Kumar Dubey ◽  
Ayush Goyal
Keyword(s):  
Image Processing ◽  
High Speed ◽  
Computation Time ◽  
Digital Signal ◽  
Instruction Set ◽  
Computationally Efficient ◽  
Specific Instruction ◽  
Processor Core ◽  
Speed Performance ◽  
Application Specific

Background: With the growing demand of image processing and the use of Digital Signal Processors (DSP), the efficiency of the Multipliers and Accumulators has become a bottleneck to get through. We revised a few patents on an Application Specific Instruction Set Processor (ASIP), where the design considerations are proposed for application-specific computing in an efficient way to enhance the throughput. Objective: The study aims to develop and analyze a computationally efficient method to optimize the speed performance of MAC. Methods: The work presented here proposes the design of an Application Specific Instruction Set Processor, exploiting a Multiplier Accumulator integrated as the dedicated hardware. This MAC is optimized for high-speed performance and is the application-specific part of the processor; here it can be the DSP block of an image processor while a 16-bit Reduced Instruction Set Computer (RISC) processor core gives the flexibility to the design for any computing. The design was emulated on a Xilinx Field Programmable Gate Array (FPGA) and tested for various real-time computing. Results: The synthesis of the hardware logic on FPGA tools gave the operating frequencies of the legacy methods and the proposed method, the simulation of the logic verified the functionality. Conclusion: With the proposed method, a significant improvement of 16% increase in throughput has been observed for 256 steps iterations of multiplier and accumulators on an 8-bit sample data. Such an improvement can help in reducing the computation time in many digital signal processing applications where multiplication and addition are done iteratively.

scholarly journals Effects of Field Processing of Sorghum Grain on Popping Traits

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 839
Author(s):  
Mitchell Kent ◽  
William Rooney
Keyword(s):  
Impact Force ◽  
Grain Sorghum ◽  
Expansion Ratio ◽  
Direct Impact ◽  
Order Of Magnitude ◽  
Rubber Belt ◽  
Sorghum Grain ◽  
Harvest Moisture ◽  
Quality Measurements

Interest in the use of popped sorghum in food products has resulted in a niche market for sorghum hybrids with high popping quality but little work has been done to assess the relative effects of field processing methods of grain on popping quality. This study evaluated the relative effects of harvest moisture and threshing methods on the popping quality of sorghum grain. A grain sorghum hybrid with good popping quality was produced during two different years in Texas wherein it was harvested at two moisture levels (low and high) and grain was removed from panicles using five different threshing methods (hand, rubber belt, metal brushes and two metal concave bar systems). Years, harvest moisture content and threshing method influenced all three popping quality measurements (popping efficacy, expansion ratio and flake size), but threshing method had an order of magnitude larger effect than either moisture level or year. While many of the interactions were significant, they did not influence the general trends observed. As such, the threshing methods with less direct impact force on the grain (hand and rubber belt) had higher popping quality than those samples threshed with greater impact force on the grain (metal-based systems). The popping quality differences between threshing system are likely due to a reduction in kernel integrity caused by the impacts to the kernel that occurred while threshing the grain. The results herein indicate that field processing of the grain, notably threshing method has significant impacts on the popping quality and should be taken into consideration when grain sorghum is harvested for popping purposes.

scholarly journals A Heuristics-Based Parthenogenetic Algorithm for the VRP with Potential Demands and Time Windows

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Chenghua Shi ◽  
Tonglei Li ◽  
Yu Bai ◽  
Fei Zhao
Keyword(s):  
Genetic Algorithm ◽  
Time Windows ◽  
Computation Time ◽  
Routing Problem ◽  
Split Delivery ◽  
Soft Time Windows ◽  
Comparison Results ◽  
Potential Demand ◽  
The Cost

We present the vehicle routing problem with potential demands and time windows (VRP-PDTW), which is a variation of the classical VRP. A homogenous fleet of vehicles originated in a central depot serves customers with soft time windows and deliveries from/to their locations, and split delivery is considered. Also, besides the initial demand in the order contract, the potential demand caused by conformity consuming behavior is also integrated and modeled in our problem. The objective of minimizing the cost traveled by the vehicles and penalized cost due to violating time windows is then constructed. We propose a heuristics-based parthenogenetic algorithm (HPGA) for successfully solving optimal solutions to the problem, in which heuristics is introduced to generate the initial solution. Computational experiments are reported for instances and the proposed algorithm is compared with genetic algorithm (GA) and heuristics-based genetic algorithm (HGA) from the literature. The comparison results show that our algorithm is quite competitive by considering the quality of solutions and computation time.

scholarly journals Great differences in performance and outcome of high-throughput sequencing data analysis platforms for fungal metabarcoding

MycoKeys ◽  
2018 ◽  
Vol 39 ◽  
pp. 29-40 ◽  
Author(s):  
Sten Anslan ◽  
R. Henrik Nilsson ◽  
Christian Wurzbacher ◽  
Petr Baldrian ◽  
Leho Tedersoo ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
Computation Time ◽  
Potential Effect ◽  
Data Sets ◽  
Sequencing Data ◽  
Operational Taxonomic Units ◽  
High Throughput Sequencing Data ◽  
Recent Developments

Along with recent developments in high-throughput sequencing (HTS) technologies and thus fast accumulation of HTS data, there has been a growing need and interest for developing tools for HTS data processing and communication. In particular, a number of bioinformatics tools have been designed for analysing metabarcoding data, each with specific features, assumptions and outputs. To evaluate the potential effect of the application of different bioinformatics workflow on the results, we compared the performance of different analysis platforms on two contrasting high-throughput sequencing data sets. Our analysis revealed that the computation time, quality of error filtering and hence output of specific bioinformatics process largely depends on the platform used. Our results show that none of the bioinformatics workflows appears to perfectly filter out the accumulated errors and generate Operational Taxonomic Units, although PipeCraft, LotuS and PIPITS perform better than QIIME2 and Galaxy for the tested fungal amplicon dataset. We conclude that the output of each platform requires manual validation of the OTUs by examining the taxonomy assignment values.

Relation of canine atrial activation sequence to anatomic landmarks

1982 ◽  
Vol 242 (3) ◽  
pp. H421-H428 ◽  
Author(s):  
H. Hayashi ◽  
R. L. Lux ◽  
R. F. Wyatt ◽  
M. J. Burgess ◽  
J. A. Abildskov
Keyword(s):  
Fiber Direction ◽  
Entry And Exit ◽  
Activation Time ◽  
Anatomic Landmarks ◽  
Crista Terminalis ◽  
Bipolar Electrodes ◽  
First Derivative ◽  
Bachmann’S Bundle ◽  
Atrial Activation ◽  
Activation Sequence

Activation sequence in the atria was investigated in 35 dogs. The atria were studied as four regions, and activation sequence in one region was determined in each experiment. In each region 60 electrograms were recorded simultaneously from bipolar electrodes. The maximal first derivative of the electrograms was taken as activation time. Dried atrial specimens, which permitted identification of pectinate muscles, crista terminalis, and the axis of fiber direction, were prepared. Nonuniform activation was demonstrated with more rapid conduction over the long axis of fiber direction and in Bachmann's bundle, crista terminalis, and pectinate muscles. These regions of rapid conduction were the same during sinus rhythm and ectopic and retrograde activation. Findings confirm the presence of paths with relatively rapid conduction in the atria and demonstrate that these are related to gross anatomic features. Findings also demonstrate that the paths are accessible to activation from multiple sites rather than insulated conduction paths with limited sites for entry and exit of activation.

Microbial Quality of Ground Beef after Simulated Freezer Failure

1981 ◽  
Vol 44 (1) ◽  
pp. 62-65 ◽  
Author(s):  
FATIMA S. ALI ◽  
FRANCES O. VANDUYNE
Keyword(s):  
Clostridium Perfringens ◽  
Microbial Quality ◽  
Ground Meat ◽  
Frozen Foods ◽  
Mean Values ◽  
Power Failure ◽  
Order Of Magnitude ◽  
Plate Counts ◽  
Coagulase Positive Staphylococci

Six lots of ground meat, obtained at intervals from a local supermarket, were frozen, and later held with other frozen foods in the freezer compartment of a refrigerator-freezer where power failure was simulated by unplugging the unit. Mean values for the counts (log10) of the beef as purchased were as follows: aerobic and psychrotrophic plate counts 6.35 and 6.66, respectively; presumptive coliforms 4.48; coagulase-positive staphylococci 4.67; and presumptive Clostridium perfringens 1.43. Presumptive salmonellae were detected in three of the six lots. Counts of the same order of magnitude as above were obtained after 7 days in the freezers, complete defrost of the meat and 6 h thereafter. Between 6 and 24 h, aerobic and psychrotrophic plate counts and numbers of coliforms and coagulase-positive staphylococci increased approximately 10-fold. Forty-eight hours after complete defrost, further increases in counts occurred. The appearance and aroma of the meat were acceptable 24 h after defrost; after 48 h, it would have been discarded because of browning, slime and off-odors.

A method of precise misorientation determination

2003 ◽  
Vol 36 (6) ◽  
pp. 1319-1323 ◽  
Author(s):  
A. Morawiec
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spatial Resolution ◽  
Standard Procedure ◽  
Good Spatial Resolution ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Achievable Accuracy ◽  
Better Than

A method that improves the accuracy of misorientations determined from Kikuchi patterns is described. It is based on the fact that some parameters of a misorientation calculated from two orientations are more accurate than other parameters. A procedure which eliminates inaccurate elements is devised. It requires at least two foil inclinations. The quality of the approach relies on the possibility to set large sample-to-detector distances and the availability of good spatial resolution of transmission electron microscopy. Achievable accuracy is one order of magnitude better than the accuracy of the standard procedure.

scholarly journals Effect of Post-Process Curing and Washing Time on Mechanical Properties of mSLA Printouts

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4856
Author(s):  
Bartłomiej Nowacki ◽  
Paweł Kowol ◽  
Mateusz Kozioł ◽  
Piotr Olesik ◽  
Jakub Wieczorek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Curing Time ◽  
Cross Sectional ◽  
Post Process ◽  
Order Of Magnitude ◽  
Static Tensile ◽  
High Roughness ◽  
Ambiguous Effect

The article discusses the influence of the post-process on the mechanical properties of elements produced with the use of the mask stereolithography (mSLA) method. Printed samples were subjected to the following post-process steps: Washing and post-curing, at various times. Then, static tensile and static bending tests were carried out, as well as Shore D hardness measurements for the inner and surface part of the sample, as well as profilographometric analysis of the surface. The post-curing time has been found to strongly affect the tensile and bending strength of printouts, and to improve their surface quality. Washing has an ambiguous effect on the strength of the printouts, but, in the end, it was found that extended washing slightly reduces the strength. Washing significantly affects the quality of the printout surface. A washing time that is too short results in a surface that strongly resembles the printing process, with high roughness. Increasing the washing time to 10 min lowers the roughness by one order of magnitude. Post-curing has also been shown to be beneficial for the cured sample with the application of shielding water. This approach results in an improvement in the flexural strength of the printouts. In general, the obtained research results indicate that, for printouts with cross-sectional dimensions of several mm, the optimal washing time is no more than 10 min and the post-curing time is at least 30 min.

scholarly journals Efficient gradient-based parameter estimation for dynamic models using qualitative data

2021 ◽  
Author(s):  
Leonard Schmiester ◽  
Daniel Weindl ◽  
Jan Hasenauer
Keyword(s):  
Parameter Estimation ◽  
Qualitative Data ◽  
Dynamic Models ◽  
Unknown Parameters ◽  
Differential Equation Models ◽  
Gradient Calculation ◽  
Order Of Magnitude ◽  
Gradient Based ◽  
Objective Function Values

AbstractMotivationUnknown parameters of dynamical models are commonly estimated from experimental data. However, while various efficient optimization and uncertainty analysis methods have been proposed for quantitative data, methods for qualitative data are rare and suffer from bad scaling and convergence.ResultsHere, we propose an efficient and reliable framework for estimating the parameters of ordinary differential equation models from qualitative data. In this framework, we derive a semi-analytical algorithm for gradient calculation of the optimal scaling method developed for qualitative data. This enables the use of efficient gradient-based optimization algorithms. We demonstrate that the use of gradient information improves performance of optimization and uncertainty quantification on several application examples. On average, we achieve a speedup of more than one order of magnitude compared to gradient-free optimization. Additionally, in some examples, the gradient-based approach yields substantially improved objective function values and quality of the fits. Accordingly, the proposed framework substantially improves the parameterization of models from qualitative data.AvailabilityThe proposed approach is implemented in the open-source Python Parameter EStimation TOolbox (pyPESTO). All application examples and code to reproduce this study are available at https://doi.org/10.5281/zenodo.4507613.

scholarly journals Colorectal bradyarrhythmia syndrome as a predictor of metabolic syndrome

2020 ◽  
Vol 183 (11) ◽  
pp. 44-50
Author(s):  
K. A. Shemerovskii ◽  
V. N. Fedorets ◽  
P. V. Seliverstov ◽  
S. R. Bakaeva
Keyword(s):  
Metabolic Syndrome ◽  
Well Being ◽  
Medical Professionals ◽  
Early Prevention ◽  
The Third ◽  
The Metabolic Syndrome ◽  
Severe Stage ◽  
Order Of Magnitude ◽  
Two Stages

Evidence is presented for a significantly wider spread of the first two stages (mild and moderate) Colorectal Bradyarrhythmia Syndrome (CBS) compared with the third (severe — constipation) stage of this syndrome. Surveyed more than 2,500 medical professionals by the method of chronoenterographia. It was found that the incidence of mild CBS (about 60% of cases) and moderate stage of this syndrome (about 30% of cases) is almost an order of magnitude higher than the incidence of severe stage (about 10% of cases) of CBS. SCB has been shown to increase the risk of obesity by almost 3 times. It is shown that CBS contributes to a decrease in well-being, activity and mood, as well as a decrease in the quality of life. Screening for CBS and normalizing the circadian bowel rhythm with psyllium (mucofalc) in individuals who consider themselves healthy may contribute to early prevention of the risk of the metabolic syndrome.

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