scholarly journals Expansion of the Laser Beam Wavefront in Terms of Zernike Polynomials in the Problem of Turbulence Testing

2021 ◽  
Vol 11 (24) ◽  
pp. 12112
Author(s):  
Alexey Rukosuev ◽  
Alexander Nikitin ◽  
Vadim Belousov ◽  
Julia Sheldakova ◽  
Vladimir Toporovsky ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Laser Radiation ◽  
Laser Beam ◽  
Standard Procedure ◽  
Higher Order ◽  
High Order ◽  
Zernike Polynomials ◽  
Taylor’S Hypothesis ◽  
Zernike Modes ◽  
Low Order

The results of a study of the wavefront distortions of laser radiation caused by artificial turbulence obtained in laboratory conditions using a fan heater are presented. Decomposition of the wavefront in terms of Zernike polynomials is a standard procedure that traditionally is used to investigate the set of existing aberrations. In addition, the spectral analysis of the wavefront dynamics makes it possible to estimate the fraction of the energy distributed between different Zernike modes. It is shown that the fraction of energy related to the low-order polynomials is higher compared to the high-order polynomials. Also, one of the consequences of Taylor’s hypothesis is confirmed—low-order aberrations are slower compared to the higher-order ones.

scholarly journals Quo Vadis Higher Order Thinking Skills (HOTS) pada Soal UM-PTKIN Materi Pendidikan Agama Islam

2020 ◽  
Vol 8 (2) ◽  
pp. 133-152
Author(s):  
Lilik Huriyah ◽  
Muhammad Fahmi ◽  
Rohaizan Baru ◽  
Wahyu Ilaihi
Keyword(s):  
Higher Order Thinking ◽  
Thinking Skills ◽  
Higher Order ◽  
High Order ◽  
Thinking Skill ◽  
Higher Order Thinking Skills ◽  
Quo Vadis ◽  
High Order Thinking ◽  
Low Order

Input sumber daya manusia di perguruan tinggi dituntut untuk memiliki kemampuan berpikir tingkat tinggi (High Order Thinking Skills, HOTS) yang meliputi kemampuan menganalisis, mengevaluasi dan mengkreasi materi. Dengan demikian, keberadaan tes masuk perguruan tinggi menjadi salah satu intrumen penting dalam melakukan seleksi sumber daya manusia. Artikel ini bertujuan  mengeksplorasi peta HOTS pada soal Ujian Masuk Perguruan Tinggi Keagamaan Islam Negeri (UM-PTKIN) materi Pendidikan Agama Islam (PAI) tahun 2018 dan perbandingan tingkat HOTS pada soal kelompok materi ujian PAI. Artikel ini juga didukung oleh hasil kajian kepustakaan. Hasil kajian menunjukkan bahwa item soal UM-PTKIN materi PAI berada pada kategori HOTS dan kemampuan berpikir tingkat rendah (Low Order Thinking Skill, LOTS). Materi Akidah Akhlak menjadi penyumbang terbanyak dan Al-Quran Hadith sebagai penyumbang paling sedikit pada soal kategori HOTS. Program Studi Pendidikan Agama Islam (PAI) adalah prodi yang sangat diminati sekaligus lulusannya sangat dinanti untuk dapat menyemai pemahaman keislaman untuk menjawab berbagai tantangan sosial, politik, dan keagamaan di Indonesia. Artikel ini memberikan rekomendasi bagi pemangku kebijakan UM-PTKIN untuk dapat meningkatkan jumlah komposisi soal HOTS dalam seleksi-seleksi selanjutnya agar dapat meningkatkan kualitas input mahasiswa PAI di periode-periode berikutnya.

Are HOLZ lines kinematic in off-zone-axis orientation?

1993 ◽  
Vol 51 ◽  
pp. 692-693
Author(s):  
J. M. Zuo ◽  
A. L. Weickenmeier ◽  
R. Holmestad ◽  
J. C. H. Spence
Keyword(s):  
Structure Determination ◽  
Standard Procedure ◽  
High Order ◽  
Zone Axis ◽  
Great Promise ◽  
Line Position ◽  
Measured Intensity ◽  
Constant Intensity ◽  
Axis Orientation ◽  
Diffraction Condition

The application of high order reflections in a weak diffraction condition off the zone axis center, including those in high order laue zones (HOLZ), holds great promise for structure determination using convergent beam electron diffraction (CBED). It is believed that in this case the intensities of high order reflections are kinematic or two-beam like. Hence, the measured intensity can be related to the structure factor amplitude. Then the standard procedure of structure determination in crystallography may be used for solving unknown structures. The dynamic effect on HOLZ line position and intensity in a strongly diffracting zone axis is well known. In a weak diffraction condition, the HOLZ line position may be approximated by the kinematic position, however, it is not clear whether this is also true for HOLZ intensities. The HOLZ lines, as they appear in CBED patterns, do show strong intensity variations along the line especially near the crossing of two lines, rather than constant intensity along the Bragg condition as predicted by kinematic or two beam theory.

VERY HIGH-ORDER SPATIALLY IMPLICIT SCHEMES FOR COMPUTATIONAL ACOUSTICS ON CURVILINEAR MESHES

2001 ◽  
Vol 09 (04) ◽  
pp. 1259-1286 ◽  
Author(s):  
MIGUEL R. VISBAL ◽  
DATTA V. GAITONDE
Keyword(s):  
Three Dimensional ◽  
Radiation Condition ◽  
Higher Order ◽  
High Order ◽  
High Frequencies ◽  
Decomposition Strategies ◽  
The Impact ◽  
Spurious Modes ◽  
Very High ◽  
Computational Strategy

A high-order compact-differencing and filtering algorithm, coupled with the classical fourth-order Runge–Kutta scheme, is developed and implemented to simulate aeroacoustic phenomena on curvilinear geometries. Several issues pertinent to the use of such schemes are addressed. The impact of mesh stretching in the generation of high-frequency spurious modes is examined and the need for a discriminating higher-order filter procedure is established and resolved. The incorporation of these filtering techniques also permits a robust treatment of outflow radiation condition by taking advantage of energy transfer to high-frequencies caused by rapid mesh stretching. For conditions on the scatterer, higher-order one-sided filter treatments are shown to be superior in terms of accuracy and stability compared to standard explicit variations. Computations demonstrate that these algorithmic components are also crucial to the success of interface treatments created in multi-domain and domain-decomposition strategies. For three-dimensional computations, special metric relations are employed to assure the fidelity of the scheme in highly curvilinear meshes. A variety of problems, including several benchmark computations, demonstrate the success of the overall computational strategy.

Polynomial Moving Fitting Method for Edge Identification

2011 ◽  
Vol 308-310 ◽  
pp. 2560-2564 ◽  
Author(s):  
Xiang Rong Yuan
Keyword(s):  
Edge Detection ◽  
Curve Fitting ◽  
Polynomial Function ◽  
High Order ◽  
Polynomial Fitting ◽  
Fitting Method ◽  
Order Polynomial ◽  
Better Than ◽  
Low Order

A moving fitting method for edge detection is proposed in this work. Polynomial function is used for the curve fitting of the column of pixels near the edge. Proposed method is compared with polynomial fitting method without sub-segment. The comparison shows that even with low order polynomial, the effects of moving fitting are significantly better than that with high order polynomial fitting without sub-segment.

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