scholarly journals Frequency multiplexed coherent φ-OTDR

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hannah M. Ogden ◽  
Matthew J. Murray ◽  
Joseph B. Murray ◽  
Clay Kirkendall ◽  
Brandon Redding
Keyword(s):  
Numerical Analysis ◽  
Pulse Train ◽  
State Of The Art ◽  
Average Power ◽  
Comprehensive Analysis ◽  
Experimental Measurements ◽  
Rayleigh Backscattering ◽  
Sensor Performance ◽  
Sensor Platform ◽  
Lower Noise

AbstractWe present a comprehensive analysis of a frequency multiplexed phase-measuring φ-OTDR sensor platform. The system uses a train of frequency-shifted pulses to increase the average power injected into the fiber and provide a diversity of uncorrelated Rayleigh backscattering measurements. Through a combination of simulations, numerical analysis, and experimental measurements, we show that this approach not only enables lower noise and mitigates interference fading, but also improves the sensor linearity. We investigate the sensor dependence on the length of the pulse train and characterize the sensor performance as a function of range, demonstrating operation from 1 to 50 km. Despite its relative simplicity, this platform enables state-of-the-art performance, including low crosstalk, high linearity, and a minimum detectable strain of only 0.6 p$$\varepsilon /\sqrt{\text{Hz}}$$ ε / Hz in a 10 km fiber with 10 m spatial resolution and a bandwidth of 5 kHz.

scholarly journals Social Media Adoption, Usage And Impact In Business-To-Business (B2B) Context: A State-Of-The-Art Literature Review

2021 ◽  
Author(s):  
Yogesh K. Dwivedi ◽  
Elvira Ismagilova ◽  
Nripendra P. Rana ◽  
Ramakrishnan Raman
Keyword(s):  
Social Media ◽  
Media Use ◽  
State Of The Art ◽  
Relevant Literature ◽  
Comprehensive Analysis ◽  
Social Media Use ◽  
Weight Analysis ◽  
Social Media Tools ◽  
Use Of Social Media ◽  
Business To Business

AbstractSocial media plays an important part in the digital transformation of businesses. This research provides a comprehensive analysis of the use of social media by business-to-business (B2B) companies. The current study focuses on the number of aspects of social media such as the effect of social media, social media tools, social media use, adoption of social media use and its barriers, social media strategies, and measuring the effectiveness of use of social media. This research provides a valuable synthesis of the relevant literature on social media in B2B context by analysing, performing weight analysis and discussing the key findings from existing research on social media. The findings of this study can be used as an informative framework on social media for both, academic and practitioners.

High-power ultrafast thin-disk multipass amplifiers for efficient laser-based manufacturing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marwan Abdou Ahmed ◽  
Christoph Roecker ◽  
André Loescher ◽  
Florian Bienert ◽  
Daniel Holder ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
State Of The Art ◽  
Second Harmonic ◽  
Average Power ◽  
Polycrystalline Diamond ◽  
Third Harmonic Generation ◽  
Thin Disk ◽  
Ultrafast Laser ◽  
Third Harmonic ◽  
Laser Systems

Abstract Thin-disk multipass amplifiers represent one of the most powerful approaches to scale the average and peak powers of ultrafast laser systems. The present paper presents the amplification of picosecond and femtosecond pulses to average powers exceeding 2 and 1 kW, respectively. Second-harmonic generation in lithium-triborate crystals with powers higher than 1.4 kW and 400 W at a wavelength of 515 nm with picosecond and femtosecond pulse durations, respectively, are also reported. Furthermore, third-harmonic generation was demonstrated with output powers exceeding 250 W at a wavelength of 343 nm. Finally, processing of silicon, metals, and polycrystalline diamond with fs pulses at an average power of 1 kW is presented to demonstrate removal rates that are improved by orders of magnitude as compared to state-of-the-art techniques.

Requirements Engineering for Courseware Development

2011 ◽  
pp. 170-188 ◽  
Author(s):  
Ines Grützner ◽  
Barbara Paech
Keyword(s):  
Requirements Engineering ◽  
State Of The Art ◽  
Comprehensive Analysis ◽  
Further Education ◽  
The State ◽  
Requirements Specification ◽  
Development Projects ◽  
Learning Context ◽  
Active Involvement ◽  
The Web

Technology-enabled learning using the Web and the computer and courseware, in particular, is becoming more and more important as an addition, extension, or replacement of traditional further education measures. This chapter introduces the challenges and possible solutions for requirements engineering (RE) in courseware development projects. First the state-of-the-art in courseware requirements engineering is analyzed and confronted with the most important challenges. Then the IntView methodology is described as one solution for these challenges. The main features of IntView RE are: support of all roles from all views on courseware RE; focus on the audience supported by active involvement of audience representatives in all activities; comprehensive analysis of the sociotechnical environment of the audience and the courseware as well as of the courseware learning context; coverage of all software RE activities; and development of an explicit requirements specification documentation.

Object tracking with robotic total stations: Current technologies and improvements based on image data

2017 ◽  
Vol 11 (3) ◽  
Author(s):  
Matthias Ehrhart ◽  
Werner Lienhart
Keyword(s):  
Object Tracking ◽  
State Of The Art ◽  
Image Data ◽  
Field Of View ◽  
Experimental Measurements ◽  
Wide Angle ◽  
Target Search ◽  
Total Station ◽  
Machine Control ◽  
Wide Angle Camera

AbstractThe importance of automated prism tracking is increasingly triggered by the rising automation of total station measurements in machine control, monitoring and one-person operation. In this article we summarize and explain the different techniques that are used to coarsely search a prism, to precisely aim at a prism, and to identify whether the correct prism is tracked. Along with the state-of-the-art review, we discuss and experimentally evaluate possible improvements based on the image data of an additional wide-angle camera which is available for many total stations today. In cases in which the total station’s fine aiming module loses the prism, the tracked object may still be visible to the wide-angle camera because of its larger field of view. The theodolite angles towards the target can then be derived from its image coordinates which facilitates a fast reacquisition of the prism. In experimental measurements we demonstrate that our image-based approach for the coarse target search is 4 to 10-times faster than conventional approaches.

Computer Programs

1965 ◽  
Vol 19 (1) ◽  
pp. 84-84
Keyword(s):  
Data Processing ◽  
State Of The Art ◽  
Electronic Computer ◽  
Rapid Change ◽  
Computer Programs ◽  
Comprehensive Analysis ◽  
Computer Hardware ◽  
Output Data ◽  
General Program ◽  
Selection Of

“The state of the art” of computer programs, which have been developed for geodetic purposes, is portrayed in the following six papers. Each report has been condensed to give an indication of what the program can do, but no attempt has been made to indicate any detail of the programs. It is generally the experience of programers that a program is never static. By the time one edition has been checked out (“debugged” is the jargon of the craft), the programer has already started to work on the next edition. In this sense, many of the programs that were discussed in October may be superseded before this report is printed. In part, this reflects the rapid change in computer hardware. Computers, themselves, are frequently obsolete soon after they are put into service. Each change of computer requires at least minor changes in programs; more flexibility in programs, in turn, encourages more comprehensive analysis of the data and the selection of alternative formats for output data. In general, a much better job of data processing can be, and is being, done with the help of the electronic computer. It is the consensus that the user of a program must understand it and be capable of modifying it to suit his particular requirements. The dream of a general program into which anyone can feed his data and from which he will get perfect results remains a dream.

Numerical analysis of state of the art high performance thermoplastic composite as light weight bullet proof material

2019 ◽  
Vol 6 (9) ◽  
pp. 095333 ◽  
Author(s):  
Meenakshi S ◽  
Neeraj Srinivas ◽  
Y Sai Siddarth ◽  
Ch V S Kamal ◽  
Sudheendra K ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
High Performance ◽  
State Of The Art ◽  
Thermoplastic Composite ◽  
Light Weight

scholarly journals Using Natural Language Processing and Artificial Intelligence to Explore the Nutrition and Sustainability of Recipes and Food

2021 ◽  
Vol 3 ◽  
Author(s):  
Marieke van Erp ◽  
Christian Reynolds ◽  
Diana Maynard ◽  
Alain Starke ◽  
Rebeca Ibáñez Martín ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Natural Language Processing ◽  
Natural Language ◽  
Language Processing ◽  
Domain Knowledge ◽  
State Of The Art ◽  
Interdisciplinary Approach ◽  
Comprehensive Analysis ◽  
The State ◽  
Use Cases

In this paper, we discuss the use of natural language processing and artificial intelligence to analyze nutritional and sustainability aspects of recipes and food. We present the state-of-the-art and some use cases, followed by a discussion of challenges. Our perspective on addressing these is that while they typically have a technical nature, they nevertheless require an interdisciplinary approach combining natural language processing and artificial intelligence with expert domain knowledge to create practical tools and comprehensive analysis for the food domain.

The State of the Art in Numerical Analysis.

1988 ◽  
Vol 51 (183) ◽  
pp. 386
Author(s):  
W. G. ◽  
A. Iserles ◽  
M. J. D. Powell
Keyword(s):  
Numerical Analysis ◽  
State Of The Art ◽  
The State
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