scholarly journals TomoSAR Imaging for the Study of Forested Areas: A Virtual Adaptive Beamforming Approach

2018 ◽  
Vol 10 (11) ◽  
pp. 1822 ◽  
Author(s):  
Gustavo Martín del Campo ◽  
Yuriy Shkvarko ◽  
Andreas Reigber ◽  
Matteo Nannini
Keyword(s):  
Structural Model ◽  
Imaging Techniques ◽  
Resolution Enhancement ◽  
Adaptive Beamforming ◽  
Irregular Sampling ◽  
Multi Stage ◽  
Forested Areas ◽  
German Aerospace ◽  
Design Regularization ◽  
Non Parametric

Among the objectives of the upcoming space missions Tandem-L and BIOMASS, is the 3-D representation of the global forest structure via synthetic aperture radar (SAR) tomography (TomoSAR). To achieve such a goal, modern approaches suggest solving the TomoSAR inverse problems by exploiting polarimetric diversity and structural model properties of the different scattering mechanisms. This way, the related tomographic imaging problems are treated in descriptive regularization settings, applying modern non-parametric spatial spectral analysis (SSA) techniques. Nonetheless, the achievable resolution of the commonly performed SSA-based estimators highly depends on the span of the tomographic aperture; furthermore, irregular sampling and non-uniform constellations sacrifice the attainable resolution, introduce artifacts and increase ambiguity. Overcoming these drawbacks, in this paper, we address a new multi-stage iterative technique for feature-enhanced TomoSAR imaging that aggregates the virtual adaptive beamforming (VAB)-based SSA approach, with the wavelet domain thresholding (WDT) regularization framework, which we refer to as WAVAB (WDT-refined VAB). First, high resolution imagery is recovered applying the descriptive experiment design regularization (DEDR)-inspired reconstructive processing. Next, the additional resolution enhancement with suppression of artifacts is performed, via the WDT-based sparsity promoting refinement in the wavelet transform (WT) domain. Additionally, incorporation of the sum of Kronecker products (SKP) decomposition technique at the pre-processing stage, improves ground and canopy separation and allows for the utilization of different better adapted TomoSAR imaging techniques, on the ground and canopy structural components, separately. The feature enhancing capabilities of the novel robust WAVAB TomoSAR imaging technique are corroborated through the processing of airborne data of the German Aerospace Center (DLR), providing detailed volume height profiles reconstruction, as an alternative to the competing non-parametric SSA-based methods.

scholarly journals Determinants of Patient-Directed Citizenship Behaviors of Nurses in Thailand: A Motivation Model

2019 ◽  
Vol 15 (8) ◽  
pp. 94
Author(s):  
Ratana Somrongthong ◽  
Kanon Trichandhara
Keyword(s):  
Public Service ◽  
Structural Model ◽  
Cross Sectional Study ◽  
Transformational Leaders ◽  
Citizenship Behaviors ◽  
Sectional Study ◽  
Cross Sectional ◽  
Multi Stage ◽  
Southern Border ◽  
Motivation Model

This cross-sectional study explored how transformational leaders and public service motives impacted patient-directed citizenship behaviors of the nurses in three southern border provinces of Thailand. The participants of 813 nurses were selected via multi-stage sampling. A questionnaire was employed as its instrument. The structural model analysis revealed a congruence between the hypothesized model and the empirical data where

An overview of structured illumination microscopy: recent advances and perspectives

2021 ◽  
Author(s):  
Krishnendu Samanta ◽  
Joby Joseph
Keyword(s):  
Spatial Frequency ◽  
Basic Principle ◽  
Imaging Techniques ◽  
Resolution Enhancement ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Structured Illumination ◽  
Post Processing ◽  
Structured Illumination Microscopy ◽  
Near Future

Abstract Structured illumination microscopy (SIM) is one of the most significant widefield super-resolution optical imaging techniques. The conventional SIM utilizes a sinusoidal structured pattern to excite the fluorescent sample; which eventually down-modulates higher spatial frequency sample information within the diffraction-limited passband of the microscopy system and provides around two-fold resolution enhancement over diffraction limit after suitable computational post-processing. Here we provide an overview of the basic principle, image reconstruction, technical development of the SIM technique. Nonetheless, in order to push the SIM resolution further towards the extreme nanoscale dimensions, several different approaches are launched apart from the conventional SIM. Among the various SIM methods, some of the important techniques e.g. TIRF, non-linear, plasmonic, speckle SIM etc. are discussed elaborately. Moreover, we highlight different implementations of SIM in various other imaging modalities to enhance their imaging performances with augmented capabilities. Finally, some future outlooks are mentioned which might develop fruitfully and pave the way for new discoveries in near future.

scholarly journals Multi-Stage Antenna Selection for Adaptive Beamforming in MIMO Radar

2020 ◽  
Vol 68 ◽  
pp. 1374-1389 ◽  
Author(s):  
Hamed Nosrati ◽  
Elias Aboutanios ◽  
David Smith
Keyword(s):  
Antenna Selection ◽  
Mimo Radar ◽  
Adaptive Beamforming ◽  
Multi Stage ◽  
Selection For

scholarly journals Analisis kemampuan VO2max cabang olahraga beladiri

2021 ◽  
Vol 10 (1) ◽  
pp. 78-88
Author(s):  
Y. Touvan Juni Samodra ◽  
Mashud Mashud
Keyword(s):  
Test Data ◽  
Multi Stage ◽  
Non Parametric

Pondasi untuk melakukan aktivitas dalam waktu yang lama, salah satunya adalah kemampuan VO2max. Kemampuan VO2max tidak secara mudah dan singkat dimiliki oleh setiap atlet, perlu latihan yang lama dengan dosis yang tepat. Cabang olahraga beladiri  dalam pertandingan memerlukan intensitas yang tinggi dalam waktu yang relative singkat. Berdasarkan hal ini maka kemampuan VO2max atlet seharusnya tinggi. Tujuan penelitian ini  adalah untuk melihat kemampuan VO2max empat cabang olahraga (cabor) beladiri (judo, karate, taekwondo dan kempo) yang mengikuti tes seleksi untuk kepentingan pemusatan latihan. Sampel adalah atlet keempat cabor tersebut yang berjumlah 45 atlet yang terdiri dari, judo (11), karate (16), taekwondo (10) dan Kempo (8). Instrumen tes yang dipergunakan adalah beep multi stage test. Data dianalisis dengan statistik deskriptif dan uji non parametric. Hasil penelitian menggambarkan bahwa rerata VO2max atlet beladiri adalah 34.75. Nilai VO2max ini bukanlah nilai yang tinggi untuk atlet. Dibuktikan lebih lanjut di antara keempat cabor beladiri ini dengan uji beda non parametric ternyata bedasaran uji kruskal wallis test hasilnya ditemukan signifikansi 0.119. Hasil ini mengindikasikan bahwa tidak terdapat perbedaan VO2max di antara keempat cabor tersebut. Kesimpulan dalam penelitian ini kemampuan VO2max cabang olahraga beladiri masih dalam kategori rendah.

Correlative STM, FESEM, and TEM studies of fibrillar structures in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 866-867 ◽  
Author(s):  
I. H. Musselman ◽  
P.E. Russell ◽  
R.T. Chen ◽  
M.G. Jamieson ◽  
L.C. Sawyer
Keyword(s):  
Liquid Crystalline ◽  
Structural Model ◽  
Imaging Techniques ◽  
Ion Beam ◽  
Crystalline Polymer ◽  
Sample Surface ◽  
Scanning Tunneling ◽  
Ion Beam Sputtering ◽  
Tunneling Microscopy ◽  
Beam Sputtering

Hierarchical fibrillar structures have been reported to be present in liquid crystalline polymer (LCP) extrudates such as fibers and tapes. Using conventional scanning and transmission electron microscopy (SEM, TEM), the smallest fibrils were shown to be about 50 nm wide and 5 nm thick. With the emergence of higher resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission SEM (FESEM), we have been able to further explore the ultrastructures in the LCP fibrils and extend the LCP structural model.The LCP materials investigated consist of copolyesters of 4-hydroxybenzoic acid (HBA) and 2- hydroxy-6-napthoic acid (HNA) in the form of melt-spun fibers and extruded tapes. These materials exhibit unidirectionally-oriented structures as revealed by x-ray diffraction and microscopy studies. For STM and FESEM, samples were prepared by a peel-back method which reveals the internal structures of fibrils. In addition, ultrasonication was used to disintegrate the LCP fibers and tapes to provide fine “fibrillar” samples for STM, FESEM, and TEM studies. The original tape and fiber surfaces were also examined by STM and FESEM. Thin Pt coatings (ca. 5 nm) were deposited on the LCP samples using ion beam sputtering to provide a conducting surface for STM and FESEM imaging. These coatings have been shown to introduce minimal topography to the original sample surface.

scholarly journals Signal Processing of GPR Data for Road Surveys

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 96 ◽  
Author(s):  
Luca Bianchini Ciampoli ◽  
Fabio Tosti ◽  
Nikos Economou ◽  
Francesco Benedetto
Keyword(s):  
Signal Processing ◽  
Resolution Enhancement ◽  
Real Life ◽  
Destructive Testing ◽  
V Band ◽  
Remaining Service Life ◽  
Multi Stage ◽  
Band Pass ◽  
Ground Penetrating ◽  
Non Destructive

Effective quality assurance and quality control inspections of new roads as well as assessment of remaining service-life of existing assets is taking priority nowadays. Within this context, use of ground penetrating radar (GPR) is well-established in the field, although standards for a correct management of datasets collected on roads are still missing. This paper reports a signal processing method for data acquired on flexible pavements using GPR. To demonstrate the viability of the method, a dataset collected on a real-life flexible pavement was used for processing purposes. An overview of the use of non-destructive testing (NDT) methods in the field, including GPR, is first given. A multi-stage method is then presented including: (i) raw signal correction; (ii) removal of lower frequency harmonics; (iii) removal of antenna ringing; (iv) signal gain; and (v) band-pass filtering. Use of special processing steps such as vertical resolution enhancement, migration and time-to-depth conversion are finally discussed. Key considerations about the effects of each step are given by way of comparison between processed and unprocessed radargrams. Results have proven the viability of the proposed method and provided recommendations on use of specific processing stages depending on survey requirements and quality of the raw dataset.

scholarly journals Investigation of the Relationship Between Psychological Capital Perception, Psychological Well-Being and Job Satisfaction of Teachers

2018 ◽  
Vol 8 (1) ◽  
pp. 87 ◽  
Author(s):  
Neslihan Kurt ◽  
Ayşe Ottekin Demirbolat
Keyword(s):  
Job Satisfaction ◽  
Sampling Method ◽  
Structural Model ◽  
Psychological Capital ◽  
Simple Random Sampling ◽  
Well Being ◽  
Psychological Well Being ◽  
Minnesota Satisfaction Questionnaire ◽  
Multi Stage ◽  
The Relationship

The aim of this research is to determine the relationship between psychological capital, psychological well-being and job satisfaction of teachers. The research is a descriptive study in relational screening model. The research model includes three variables; one independent variable (psychological capital) and other two dependent variables (job satisfaction and psychological well-being). In the structural model, job satisfaction variable may also be expressed as mediator variable. The study population consists of 12714 teachers working in official secondary schools in seven central districts in Ankara Province in 2017-2018 academic year. Sample of the population is selected by multi-stage sampling method. Stratified sampling method is used in the first stage and simple random sampling method is used in the second stage. Sample size is calculated as at least 384 teachers. In the research, Psychological Capital Scale developed by Luthans, Youssef & Avolio (2007b); Minnesota Satisfaction Questionnaire developed by Weiss, Dawis, Lofquist & England (1967) and Psychological Well-Being Scale developed by Ryff (1989) were used as data collection tools. Scales which are pre-implemented within the scope of the research yielded valid and reliable results. Data analysis was done with SPSS 23.0 and LISREL 8.87 statistics software packages. According to the results obtained from the research, it was determined that teachers’ psychological capital perception was “good” and their job satisfaction and psychological well-being are “high”. According to the results of the analysis by means of structural equality modelling, it was determined that teachers’ psychological capital perception affects their job satisfaction and psychological well-being levels positively and predicts them significantly; and it was also determined that job satisfaction has a partial mediator role in the relationship between teachers’ psychological capital perception and their psychological well-being.

Quantitative electron holography applied to crystal wedges and interfaces

1993 ◽  
Vol 51 ◽  
pp. 1090-1091
Author(s):  
M. Gajdardziska-Josifovska
Keyword(s):  
Imaging Techniques ◽  
Resolution Enhancement ◽  
Electron Holography ◽  
Electron Wave ◽  
Exit Surface ◽  
Transmission Electron ◽  
Wide Range ◽  
Original Goal ◽  
Microscopy Techniques ◽  
Crystal Interfaces

Electron holography is unique among transmission electron microscopy techniques in that it allows retrieval of phase of the electron wave, information which is lost with other imaging techniques. With access to the phase, interactions of the incident electron wave with the electrostatic and magnetic potentials of the specimen can be studied directly with high spatial resolution. Besides resolution enhancement, the original goal for electron holography, applications to wide range of materials problems are currently under investigation. This work will address applications to measurements of mean inner potential of crystals and to epitaxial crystal interfaces.In non-magnetic materials, in the absence of external electrical fields and/or charge layers, the electrostatic potential which alters the phase of the exit surface wave results from the atomic potentials. For amorphous and polycrystalline samples of known thickness, the phase change depends on the volume average of the atomic potentials, i.e. the mean inner potential V0.

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