Method for optimizing the errors of the wavefront of recorded radiation for large-size information-measuring optical systems

2021 ◽  
pp. 57-61
Author(s):  
Victor V. Sychev ◽  
Andrey I. Klem
Keyword(s):  
Traditional Method ◽  
Optimization Problem ◽  
Optical Systems ◽  
Field Variation ◽  
Large Telescope ◽  
Size Information ◽  
Image Field ◽  
Advantages And Disadvantages ◽  
Large Size ◽  
Secondary Mirror

The article proposes a new method for increasing the information content of the image by minimizing the errors of the optical system of a large telescope using the redistribution of errors over the image field. Variation of the parameters of the secondary mirror is carried out to solve the optimization problem of uniform distribution of aberrations over the image field of a large telescope using the example of a cryotelescope with a diameter of 12 m in the Zemax-EE package. The results of calculations of optical schemes by the traditional method and by the method of optimization of the errors of the radiation wavefront are presented. The advantages and disadvantages are considered.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

Three Approaches for Managing Stiffness in Origami-Inspired Mechanisms

2018 ◽  
Author(s):  
Alden Yellowhorse ◽  
Larry L. Howell
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Engineering Applications ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Large Size ◽  
Selection For

Ensuring that deployable mechanisms are sufficiently rigid is a major challenge due to their large size relative to their mass. This paper examines three basic types of stiffener that can be applied to light, origami-inspired structures to manage their stiffness. These stiffeners are modeled analytically to enable prediction and optimization of their behavior. The results obtained from this analysis are compared to results from a finite-element analysis and experimental data. After verifying these models, the advantages and disadvantages of each stiffener type are considered. This comparison will facilitate stiffener selection for future engineering applications.

The secondary mirror concept for the European Extremely Large Telescope

2014 ◽  
Author(s):  
Michael Mueller ◽  
Marc Cayrel ◽  
Henri Bonnet ◽  
Emanuela Ciattaglia ◽  
Michael Esselborn ◽  
...  
Keyword(s):  
Large Telescope ◽  
Secondary Mirror

Statistical Properties of Wavefront and Image Field of Misaligned Segmented Optical Systems

2019 ◽  
Vol 39 (11) ◽  
pp. 1111004
Author(s):  
张永峰 Zhang Yongfeng ◽  
鲜浩 Xian Hao
Keyword(s):  
Statistical Properties ◽  
Optical Systems ◽  
Image Field

scholarly journals Autonomous and In Situ Ocean Environmental Monitoring on Optofluidic Platform

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 69 ◽  
Author(s):  
Fang Wang ◽  
Jiaomeng Zhu ◽  
Longfei Chen ◽  
Yunfeng Zuo ◽  
Xuejia Hu ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Chemical Elements ◽  
Biogeochemical Cycles ◽  
Chemical Parameters ◽  
Advantages And Disadvantages ◽  
Large Size ◽  
High Power Consumption ◽  
Marine Disasters ◽  
Ocean Monitoring

Determining the distributions and variations of chemical elements in oceans has significant meanings for understanding the biogeochemical cycles, evaluating seawater pollution, and forecasting the occurrence of marine disasters. The primary chemical parameters of ocean monitoring include nutrients, pH, dissolved oxygen (DO), and heavy metals. At present, ocean monitoring mainly relies on laboratory analysis, which is hindered in applications due to its large size, high power consumption, and low representative and time-sensitive detection results. By integrating photonics and microfluidics into one chip, optofluidics brings new opportunities to develop portable microsystems for ocean monitoring. Optofluidic platforms have advantages in respect of size, cost, timeliness, and parallel processing of samples compared with traditional instruments. This review describes the applications of optofluidic platforms on autonomous and in situ ocean environmental monitoring, with an emphasis on their principles, sensing properties, advantages, and disadvantages. Predictably, autonomous and in situ systems based on optofluidic platforms will have important applications in ocean environmental monitoring.

Direct Display of X-ray Topographic Images

1976 ◽  
Vol 20 ◽  
pp. 221-235
Author(s):  
Green Robert E
Keyword(s):  
State Of The Art ◽  
Direct Conversion ◽  
Optical Systems ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Resolution Capability

The purpose of the present paper is to give a comprehensive state of the art review of all electro-optical systems used to date for direct viewing of X-ray topographic images. Consideration is given to both direct conversion X-ray sensitive vidicon systems and to indirect conversion systems which use fluorescent screens to convert the X-ray image into a visible one. Included in this review is a discussion of the relative advantages and disadvantages of the various electro-optical systems, including cost, versatility, portability, simplicity of operation, sensitivity, and resolution capability.

Metaheuristics Guided by the Apriori Principle for Association Rule Mining

2020 ◽  
Vol 10 (3) ◽  
pp. 14-37
Author(s):  
Abir Derouiche ◽  
Abdesslem Layeb ◽  
Zineb Habbas
Keyword(s):  
Association Rule ◽  
Association Rule Mining ◽  
Optimization Problem ◽  
Chemical Reaction Optimization ◽  
Exact Methods ◽  
Rule Mining ◽  
Hybrid Approaches ◽  
Large Size ◽  
Reaction Optimization ◽  
First Results

Association rule mining (ARM), one of the most known tasks in data mining, is considered as an optimization problem. The ARM problem can be solved either by exact methods or by metaheuristics. Exact methods such as Apriori algorithm are very efficient to deal with small and medium datasets. However, when dealing with large size datasets, these methods suffer from time complexity. Metaheuristics are proven faster but most of them suffer from accuracy. To deal with these two challenging issues, this work investigates to enhance metaheuristics and proposes hybrid approaches, which combine metaheuristics and the Apriori principle to intelligently explore the association rules space. To validate the proposed approaches the chemical reaction optimization metaheuristic (CRO) was used. Intensive experiments have been carried out and the first results are very promising in terms of accuracy and processing time.

scholarly journals Combining Polyhedral Approaches and Stochastic Dual Dynamic Integer Programming for Solving the Uncapacitated Lot-Sizing Problem Under Uncertainty

2021 ◽  
Author(s):  
Franco Quezada ◽  
Céline Gicquel ◽  
Safia Kedad-Sidhoum
Keyword(s):  
Integer Programming ◽  
Production Planning ◽  
Optimization Problem ◽  
Lot Sizing ◽  
Computational Experiments ◽  
Scenario Tree ◽  
Partial Decomposition ◽  
Large Size ◽  
Lot Sizing Problem ◽  
Planning Problems

We study the uncapacitated lot-sizing problem with uncertain demand and costs. The problem is modeled as a multistage stochastic mixed-integer linear program in which the evolution of the uncertain parameters is represented by a scenario tree. To solve this problem, we propose a new extension of the stochastic dual dynamic integer programming algorithm (SDDiP). This extension aims at being more computationally efficient in the management of the expected cost-to-go functions involved in the model, in particular by reducing their number and by exploiting the current knowledge on the polyhedral structure of the stochastic uncapacitated lot-sizing problem. The algorithm is based on a partial decomposition of the problem into a set of stochastic subproblems, each one involving a subset of nodes forming a subtree of the initial scenario tree. We then introduce a cutting plane–generation procedure that iteratively strengthens the linear relaxation of these subproblems and enables the generation of an additional strengthened Benders’ cut, which improves the convergence of the method. We carry out extensive computational experiments on randomly generated large-size instances. Our numerical results show that the proposed algorithm significantly outperforms the SDDiP algorithm at providing good-quality solutions within the computation time limit. Summary of Contribution: This paper investigates a combinatorial optimization problem called the uncapacitated lot-sizing problem. This problem has been widely studied in the operations research literature as it appears as a core subproblem in many industrial production planning problems. We consider a stochastic extension in which the input parameters are subject to uncertainty and model the resulting stochastic optimization problem as a multistage stochastic integer program. To solve this stochastic problem, we propose a novel extension of the recently published stochastic dual dynamic integer programming (SDDiP) algorithm. The proposed extension relies on two main ideas: the use of a partial decomposition of the scenario tree and the exploitation of existing knowledge on the polyhedral structure of the stochastic uncapacitated lot-sizing problem. We provide the results of extensive computational experiments carried out on large-size randomly generated instances. These results show that the proposed extended algorithm significantly outperforms the SDDiP at providing good-quality solutions for the stochastic uncapacitated lot-sizing problem. Although the paper focuses on a basic lot-sizing problem, the proposed algorithmic framework may be useful to solve more complex practical production planning problems.

scholarly journals Multi-Wavelength Analytical Ultracentrifugation of Biopolymer Mixtures and Interactions

2021 ◽  
Author(s):  
Borries Demeler ◽  
Amy Henrickson ◽  
Gary Gorbet ◽  
Alexey Savelyev ◽  
Minji Kim ◽  
...  
Keyword(s):  
Small Molecules ◽  
Analytical Ultracentrifugation ◽  
Optical Systems ◽  
Hydrodynamic Properties ◽  
Advantages And Disadvantages ◽  
Design Considerations ◽  
Free Dna ◽  
Wide Range ◽  
Analysis Strategies ◽  
Multi Wavelength

Abstract Multi-wavelength analytical ultracentrifugation (MW-AUC) is a recent development made possible by new analytical ultracentrifuge optical systems. MW-AUC is suitable for a wide range of applications and biopolymer systems and is poised to become an essential tool to characterize macromolecular interactions. It adds an orthogonal spectral dimension to the traditional hydrodynamic characterization by exploiting unique chromophores in analyte mixtures that may or may not interact. Here we illustrate the utility of MW-AUC for representative classes of challenging biopolymer systems, including interactions between mixtures of different sized proteins with small molecules, mixtures of loaded and empty viral AAV capsids contaminated with free DNA, and mixtures of different proteins, where some have identical hydrodynamic properties, all of which are difficult to resolve with traditional AUC methods. We explain the improvement in resolution and information content obtained by this technique compared to traditional single- or dual-wavelength approaches. We discuss experimental design considerations and limitations of the method, and address the advantages and disadvantages of the two MW optical systems available today, and the differences in data analysis strategies between the two systems.

Comparison Analysis of GFRP Anchor Pile Performance in Expansive Soil Foundation

2013 ◽  
Vol 859 ◽  
pp. 243-247
Author(s):  
Xue Jun Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Traditional Method ◽  
Expansive Soil ◽  
Comparison Analysis ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Advantages And Disadvantages ◽  
Soil Foundation ◽  
Soil Area

GFRP anchor pile is to be researched and promoted in expansive soil foundation of tower buildings and underground buildings. Expansive soil area was selected, and comparison scheme of reinforced concrete anchor pile and GFRP anchor pile was designed. Uplift and compressive ultimate bearing capacity comparison experiment was done by one grouting, twice grouting, water cement ratio and soak. The performance of the two types of anchor pile each has advantages and disadvantages. Durability, safety, economy are considered, and traditional method of anchor pile can be improved. GFRP anchor pile and reinforced concrete anchor pile can be used in combination, and that can be better used in expansive soil foundation.

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