Microwave hologram reconstruction for cylindrical geometry

2021 ◽  
Author(s):  
V.V. Razevig ◽  
A.I. Ivashov ◽  
A.S. Bugaev
Keyword(s):  
Electromagnetic Waves ◽  
Back Propagation ◽  
Random Access ◽  
Cylindrical Geometry ◽  
Software Implementation ◽  
Radar Signal ◽  
Advantages And Disadvantages ◽  
Reconstruction Methods ◽  
Solid Objects

Microwave imaging is a technique for evaluation of hidden or embedded objects in an optically opaque structure (or media) using electromagnetic waves in microwave regime. The result of the study is a microwave image of the internal structure of the investigated object, which is built by reconstructing the electromagnetic field scattered by the object (microwave hologram), recorded using some radar system at some aperture. Along with the widespread flat aperture, a cylindrical aperture is often used in personnel screening systems, microwave system for automated body measurement for apparel fitting, and medical tomographic scanners. Cylindrical geometry requires special holograms reconstruction methods. The work is dedicated to comparison of three hologram reconstruction methods: №1 – back projection, №2 – back propagation and №3 – Gauss–Newton, and identifying the advantages and disadvantages of each method. All methods were adopted to cylindrical geometry, software implemented using Python programming language and compared. Comparison was performed by reconstruction of microwave holograms of the same objects. Microwave holograms for comparison were calculated in accordance with the principles of physical optics for point scatterers and using the computational electromagnetics software product FEKO for solid objects. Comparison criteria were: speed of calculations, quality of obtained microwave images, required random access memory (RAM) of the computer. Based on the results of numerical experiments, the following conclusions can be made. For both point and solid objects, all methods have showed a similar quality of the obtained microwave images, the difference turned out to be minimal both in visual and numerical estimation. The advantage of method №1 is the simplicity of its software implementation. In addition, using the first method, you can easily do reconstruction for any area (line, surface, volume), the position of which can be arbitrary in relation to the positions of the samples of the radar signal. Method №2 is the fastest method. With the parameters considered in the article, it is two orders of magnitude faster than method №1, and its performance can be easily increased by parallelizing calculations for different radii. Among the shortcomings, one can note the complexity of its software implementation and the dependence of the position and size of the reconstructed area on the location and number of samples of the radar signal. A significant drawback of method №3 is its high requirements to the RAM of the computer, as well as low speed of calculations. When processing microwave holograms with a large number of samples, calculations may require more memory than is installed in the computer, and the calculation time will increase many times due to the continuous exchange of data with the hard disk, or it will be impossible to do the calculations at all.

Can trust become a factor of economic growth? Dynamic changes in the level of trust of Russian youth

2020 ◽  
pp. 92-107 ◽  
Author(s):  
A. I. Bakhtigaraeva ◽  
A. A. Stavinskaya
Keyword(s):  
Institutional Environment ◽  
Negative Effects ◽  
Dynamic Changes ◽  
Generalized Trust ◽  
Level Of Education ◽  
Advantages And Disadvantages ◽  
The Future ◽  
Analysis Of Dynamics

The article considers the role of trust in the economy, the mechanisms of its accumulation and the possibility of using it as one of the growth factors in the future. The advantages and disadvantages of measuring the level of generalized trust using two alternative questions — about trusting people in general and trusting strangers — are analyzed. The results of the analysis of dynamics of the level of generalized trust among Russian youth, obtained within the study of the Institute for National Projects in 10 regions of Russia, are presented. It is shown that there are no significant changes in trust in people in general during the study at university. At the same time, the level of trust in strangers falls, which can negatively affect the level of trust in the country as a whole, and as a result have negative effects on the development of the economy in the future. Possible causes of the observed trends and the role of universities are discussed. Also the question about the connection between the level of education and generalized trust in countries with different quality of the institutional environment is raised.

Data Integrity Techniques in Cloud Computing: An Analysis

2017 ◽  
Vol 7 (8) ◽  
pp. 121 ◽  
Author(s):  
Neha Thakur ◽  
Aman Kumar Sharma
Keyword(s):  
Cloud Computing ◽  
Cloud Storage ◽  
Data Integrity ◽  
Advantages And Disadvantages ◽  
Security Models ◽  
Cloud Storage Service ◽  
Storage Service ◽  
Cloud Users ◽  
It Enterprises

Cloud computing has been envisioned as the definite and concerning solution to the rising storage costs of IT Enterprises. There are many cloud computing initiatives from IT giants such as Google, Amazon, Microsoft, IBM. Integrity monitoring is essential in cloud storage for the same reasons that data integrity is critical for any data centre. Data integrity is defined as the accuracy and consistency of stored data, in absence of any alteration to the data between two updates of a file or record.  In order to ensure the integrity and availability of data in Cloud and enforce the quality of cloud storage service, efficient methods that enable on-demand data correctness verification on behalf of cloud users have to be designed. To overcome data integrity problem, many techniques are proposed under different systems and security models. This paper will focus on some of the integrity proving techniques in detail along with their advantages and disadvantages.

Problems of Distance Education

2018 ◽  
Vol 7 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Rostislav Fojtík
Keyword(s):  
Distance Education ◽  
Distance Learning ◽  
Computer Science ◽  
Full Time ◽  
Advantages And Disadvantages ◽  
E Learning ◽  
Educational Requirements

Abstract Distance learning and e-learning have significantly developed in recent years. It is also due to changing educational requirements, especially for adults. The article aims to show the advantages and disadvantages of distance learning. Examples of the 20-year use of the distance learning form of computer science describe the difficulties associated with the implementation and implementation of this form of teaching. The results of students in the full-time and distance form of teaching in the bachelor’s study of computer science are compared. Long-term findings show that distant students have significantly lower scores in the first years of study than full-time bachelor students. In the following years of study, the differences diminish, and students’ results are comparable. The article describes the possibilities of improving the quality of distance learning.

Comparative Assessment of Optical Techniques for Semi-Invasive SRAM Data Read-out on an MSP430 Microcontroller

2018 ◽  
Author(s):  
Tuba Kiyan ◽  
Heiko Lohrke ◽  
Christian Boit
Keyword(s):  
Supply Voltage ◽  
Photon Emission ◽  
Random Access ◽  
Integration Time ◽  
Security Evaluation ◽  
Testing And Debugging ◽  
Advantages And Disadvantages ◽  
The Core ◽  
Voltage Signal ◽  
Chip Testing

Abstract This paper compares the three major semi-invasive optical approaches, Photon Emission (PE), Thermal Laser Stimulation (TLS) and Electro-Optical Frequency Mapping (EOFM) for contactless static random access memory (SRAM) content read-out on a commercial microcontroller. Advantages and disadvantages of these techniques are evaluated by applying those techniques on a 1 KB SRAM in an MSP430 microcontroller. It is demonstrated that successful read out depends strongly on the core voltage parameters for each technique. For PE, better SNR and shorter integration time are to be achieved by using the highest nominal core voltage. In TLS measurements, the core voltage needs to be externally applied via a current amplifier with a bias voltage slightly above nominal. EOFM can use nominal core voltages again; however, a modulation needs to be applied. The amplitude of the modulated supply voltage signal has a strong effect on the quality of the signal. Semi-invasive read out of the memory content is necessary in order to remotely understand the organization of memory, which finds applications in hardware and software security evaluation, reverse engineering, defect localization, failure analysis, chip testing and debugging.

scholarly journals Systematic Analysis of Literature on the Marketing of Healthcare Systems. Challenges for Russian and Romanian Healthcare Systems

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 656
Author(s):  
Vladimir Bulatnikov ◽  
Cristinel Petrişor Constantin
Keyword(s):  
Quality Of Healthcare ◽  
Healthcare Systems ◽  
Business Environment ◽  
Competitive Advantages ◽  
Systematic Analysis ◽  
Scientific Databases ◽  
Advantages And Disadvantages ◽  
Funds Allocation ◽  
New Perspective

This paper aims at finding the most dominant ideas about the marketing of healthcare systems highlighted in the mainstream literature, with a focus on Russia and Romania. To reach this goal, a systematic analysis of literature was conducted and various competitive advantages and disadvantages of the medical models that require special attention from the governments are considered. In this respect we examined 106 papers published during 2006 to 2020 found on four scientific databases. They were selected using inclusion and exclusion criteria according to PRISMA methodology. The main findings of the research consist of the opportunity to use marketing tools in order to improve the quality of healthcare systems in the named countries. Thus, using market orientation, the managers of healthcare systems could stimulate the innovation, the efficiency of funds allocation and the quality of medical services. The results will lead to a better quality of population life and to an increasing of life expectancy. As this paper reviews some articles from Russian literature, it can add a new perspective to the topic. These outcomes have implications for government, business environment, and academia, which should cooperate in order to develop the healthcare system using marketing strategies.

scholarly journals Adjuvant Radiotherapy after Surgical Excision in Keloids

Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 730
Author(s):  
Jeong Won Lee ◽  
Ki Ho Seol
Keyword(s):  
Quality Of Life ◽  
Side Effects ◽  
Adjuvant Therapy ◽  
Local Control ◽  
Adjuvant Radiotherapy ◽  
Surgical Excision ◽  
Recurrence Rates ◽  
High Tendency ◽  
Advantages And Disadvantages

Keloids are a benign fibroproliferative disease with a high tendency of recurrence. Keloids cause functional impairment, disfigurement, pruritus, and low quality of life. Many therapeutic options have been used for keloids. However, the high recurrence rates have led to the use of adjuvant therapy after surgical keloid excision. There are different radiotherapy regimens available, and the advantages and disadvantages of each are still unclear. The aim of this review is to explain the appropriate radiotherapy regimen for keloids as well as discuss the recent reports on keloid management with radiotherapy. Adjuvant radiotherapy after surgical excision for keloids yields excellent local control with tolerable side effects. Hypofractionated radiotherapy with a BED of more than 28 Gy (α/β value of 10) after excision is recommended in the light of its biologic background.

Is digital always better? Comparing two English print dictionaries with their digital counterparts

2020 ◽  
Author(s):  
Emma Ferrett ◽  
Stefan Dollinger
Keyword(s):  
Social Media ◽  
Mobile App ◽  
User Friendliness ◽  
Digital Medium ◽  
Advantages And Disadvantages ◽  
Oxford University ◽  
Relevant Question ◽  
Market Leader ◽  
Oxford University Press

Abstract In this paper we discuss advantages and disadvantages of e-dictionaries over print dictionaries in order to answer one increasingly relevant question: is digital always better? We compare the e-content from Oxford University Press and Merriam-Webster flagship dictionaries against their most recent print counterparts. The resulting data shows that the move from print to digital, against popular perception, results in a loss of lexicographical detail and scope. After assessing the user-friendliness of the e-dictionaries’ sites in both desktop and mobile app formats, we conclude that Merriam-Webster currently utilizes the digital medium somewhat better, while Oxford University Press is the current market leader in collaborations with tech giants such as Google. Most crucially, however, both companies have yet to devise and implement optimal ways to balance advertising noise and lexicographical content. Finally, we compare the virtual popularity of e-dictionaries according to their social media efforts and product partnerships. The greatest problem e-dictionaries currently face is that content does routinely change in unspecified and even undocumented ways. Despite these significant disadvantages, the convenience of mobile online accessibility appears to outweigh the concern with the reliability and quality of content.

scholarly journals The newly developed airborne radio-echo sounding system of the AWI as a glaciological tool

1999 ◽  
Vol 29 ◽  
pp. 231-238 ◽  
Author(s):  
U. Nixdorf ◽  
D. Steinhage ◽  
U. Meyer ◽  
L. Hempel ◽  
M. Jenett ◽  
...  
Keyword(s):  
Digital Data ◽  
Radar Signal ◽  
Ice Shelves ◽  
System Sensitivity ◽  
Ice Caps ◽  
Radio Echo Sounding ◽  
Recorded Data ◽  
Along Track ◽  
Echo Sounding

AbstractSince 1994 the Alfred Wegener Institute (AWI) has operated an airborne radio-echo sounding system for remote-sensing studies of the polar ice caps in Antarctica and in Greenland. It is used to map ice thicknesses and internal layernigs of glaciers, ice sheets and ice shelves, and is capable of penetrating ice thicknesses of up to 4 km. The system was designed and built by AWI in cooperation with Aerodata Flugmeßtechnik GmbH, Technische Umversitat Hamburg-Harburg and the Deutsches Zentrum fur Luft- und Raumfahrt e.V. The system uses state-of-the-art techniques, and results in high vertical (5 m) as well as along-track (3.25 m) resolution. The radar signal is a 150 MHz burst with a duration of 60 or 600 ns. The peak power is 1.6 kW, and the system sensitivity is 190 dB. The short backfire principle has been adopted and optimized for antennae used on Polar2, a Dormer 228-100 aircraft, resulting in an antenna gain of 14 dB each. Digital data recording allows further processing. The quality of the recorded data can be monitored on screen and as online analogue plots during the flight.

Analysis of the Test Method of Quartz Glass Optical Homogeneity

2017 ◽  
Vol 726 ◽  
pp. 414-418
Author(s):  
Bo Fu ◽  
Hui Wang ◽  
Zhu Feng Shao
Keyword(s):  
Quartz Glass ◽  
Measurement Accuracy ◽  
Test Methods ◽  
Test Method ◽  
Wavefront Aberration ◽  
Optical Homogeneity ◽  
Advantages And Disadvantages ◽  
Interference Measurement ◽  
Optical Quartz Glass

The optical quartz glass is widely applied in optical system , photo communications，inertial navigation，etc.It must have high optical homogeneity. Optical homogeneity of the optical quartz glass directly affects the wavefront quality of the optical transmission system, and changes the wavefront aberration of the system. How to accurately determine the optical homogeneity of the quartz glass is especially important. Currently，the method of test for optical homogeneity mainly used by interference principle. This paper analyzes various existing interference measurement method and test equipment. Summarized the advantages and disadvantages of various test methods，using range and measurement accuracy.

Rating assessment of economic security of municipalities in the region

2021 ◽  
Vol 97 (4) ◽  
pp. 72-81
Author(s):  
M. S. Syupova ◽  
Keyword(s):  
Local Governments ◽  
Economic Condition ◽  
Economic Security ◽  
Management Tool ◽  
Existing Problems ◽  
Advantages And Disadvantages ◽  
Current State ◽  
Regional Authorities ◽  
Negative Factors

Ensuring the economic security of municipalities is one of the key conditions for stable socio-economic de-velopment of the region. Recently, intraregional differentiation of territories has been growing, which increases the risk of the formation of negative factors that reduce the quality of life of the population. In order to neutralize and prevent acute social and economic problems, constant monitoring of the current state of the municipal econ-omy is necessary. As such a management tool, a rating assessment of the economic security of municipalities in the region can be used. The ranking of territories allows you to visualize the relative advantages and disadvantages of the development of territories. In addition, a systematic comparative analysis of controlled socio-economic pa-rameters will allow regional authorities to evaluate the results of the activities of local governments and improve the effectiveness of regional socio-economic policy. The article proposes a methodology for rating the economic security of municipalities, during which it is possible to visually assess the depth of the threats studied at the level of each territory. To this end, the proposed methodology is based on a system of indicators that identify the main problem areas of the socio-economic condition of the territories. To form the rating, the studied indicators are normalized and integral indices characterizing the level of economic security of municipalities are calculated. The methodology proposes criteria for assessing the level of municipal economic security (high; above average; aver-age; crisis; critical). According to the results of the study, a rating of municipal districts of the Khabarovsk Terri-tory was compiled. The study showed that the territories of the region are characterized by an unstable socio-economic condition. The leading positions in the rating are occupied by areas with an average level of economic security. Most municipal districts of the region have a crisis level of economic security, which provides for the de-velopment of a set of measures aimed at eliminating existing problems.

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