Summation of Contrast in Perceived Form from Texture

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 224-224
Author(s):  
P I Laurinen ◽  
L A Olzak
Keyword(s):  
Threshold Value ◽  
Sinusoidal Grating ◽  
Vertical Orientation ◽  
Similar Frequency ◽  
The Third ◽  
Wide Range ◽  
Relative Contrast ◽  
Narrow Frequency Band ◽  
Spatial Grain ◽  
Contrast Discrimination

The relative contrast of two superimposed triangles formed by truncated sinusoidal gratings determines which appears more salient. We have previously reported that the saliency of one triangle is selectively enhanced by superimposing a third grating of similar frequency but different orientation. We now ask how the contrasts of the three gratings combine to determine saliency. Stimuli were two superimposed isosceles triangles, formed by overlaying sharply truncated patches of a sinusoidal grating, one at 1.5 cycles deg−1 tilted +45°, the other at 6 cycles deg−1, tilted −45° from vertical. The sharpest-angle apexes pointed in opposite directions (left or right). Contrasts of the gratings were initially adjusted to yield equal performance when observers chose whether the more salient target pointed left or right following a brief (400 ms) monocular exposure. In each test condition a third grating of vertical orientation (spatial frequency 1.5, 3, or 6 cycles deg−1) was added to the entire stimulus at one of six contrast levels ranging from near threshold to 10 × threshold. The point of equal saliency was re-determined from psychometric functions by varying the contrast of one triangle in a 2AFC staircase procedure. The saliency of each triangle was enhanced when the third grating was matched in frequency, but no effect occurred when the third grating differed by an octave (eg was 3 cycles deg−1). Beyond some threshold value of the third grating contrast, the contrast needed to reinstate equal salience was found to be inversely proportional to the contrast of the third grating. Our results are in agreement with the characteristics of higher-level mechanisms that mediate spatial-grain and/or pattern contrast discrimination, and suggest that form-from-texture mechanisms sum component contrasts linearly over a wide range of orientations within a narrow frequency band.

A Comparative Study of the Spatial-Frequency Spectrum of Different Letter Optotypes and its Role in Target Recognition

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 214-214 ◽  
Author(s):  
S A Koskin ◽  
V F Danilichev ◽  
Y E Shelepin
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Frequency Spectrum ◽  
Brain Diseases ◽  
Sinusoidal Grating ◽  
Sensitivity Functions ◽  
Spatial Frequencies ◽  
Wide Range ◽  
Narrow Frequency Band ◽  
Spatial Frequency Spectrum

We studied the contrast sensitivity functions (CSFs) in patients with different eye and brain diseases using a computerised sinusoidal grating test with a wide range of frequencies (0.4 – 19.0 cycles deg−1), the Pelli - Robson chart and a new chart with frequency-filtered Snellen optotypes. The patients had different CSF curves with a decrease of contrast sensitivity in the low, middle, or high frequencies depending on their main disease (refraction anomalies, cataract, glaucoma, neuritis of optic nerve, brain tumours, etc). Analysis showed that optotypes in the Pelli - Robson chart have a wide-range spatial-frequency spectrum, and optotype recognition is determined not only by low spatial frequencies. We find that the recognition of standard Sloan's optotypes is determined mostly by sensitivity in the range of 9.4 – 14.0 cycles deg−1. At the same time we measured contrast sensitivity using the new filtered Snellen optotypes. Our calculations support our earlier suggestions that the new filtered optotypes have a narrow-band spatial-frequency spectrum, thus enabling selective measurement of contrast sensitivity in each narrow frequency band.

The Colonial Documentary Film in South and South-East Asia

2017 ◽  
Keyword(s):  
East Asia ◽  
Subject Matter ◽  
Documentary Film ◽  
East Asian ◽  
South East Asia ◽  
Post Colonial ◽  
Historical Perspectives ◽  
The Third ◽  
Wide Range ◽  
Global Understanding

Writing from a wide range of historical perspectives, contributors to the anthology shed new light on historical, theoretical and empirical issues pertaining to the documentary film, in order to better comprehend the significant transformations of the form in colonial, late colonial and immediate post-colonial and postcolonial times in South and South-East Asia. In doing so, this anthology addresses an important gap in the global understanding of documentary discourses, practices, uses and styles. Based upon in-depth essays written by international authorities in the field and cutting-edge doctoral projects, this anthology is the first to encompass different periods, national contexts, subject matter and style in order to address important and also relatively little-known issues in colonial documentary film in the South and South-East Asian regions. This anthology is divided into three main thematic sections, each of which crosses national or geographical boundaries. The first section addresses issues of colonialism, late colonialism and independence. The second section looks at the use of the documentary film by missionaries and Christian evangelists, whilst the third explores the relation between documentary film, nationalism and representation.

Duoethnography: A Polytheoretical Approach to (Re)Storing, (Re)Storying the Meanings That One Gives

2020 ◽  
pp. 396-423
Author(s):  
John Joseph Norris ◽  
Richard D. Sawyer
Keyword(s):  
Social Justice ◽  
Critical Theory ◽  
Third Space ◽  
The Third ◽  
The Core ◽  
Wide Range ◽  
Core Elements ◽  
Feminist Inquiry

This chapter summarizes the advancement of duoethnography throughout its fifteen-year history, employing examples from a variety of topics in education and social justice to provide a wide range of approaches that one may take when conducting a duoethnography. A checklist articulates what its cofounders consider the core elements of duoethnographies, additional features that may or may not be employed and how some studies purporting to be duoethnographies may not be so. The chapter indicates connections between duoethnography and a number of methodological concepts including the third space, the problematics of representation, feminist inquiry, and critical theory using published examples by several duoethnographers.

The role of slow magnetostrophic waves in dipole formation in rapidly rotating dynamos

2021 ◽  
Author(s):  
Aditya Varma ◽  
Binod Sreenivasan
Keyword(s):  
Magnetic Field ◽  
Threshold Value ◽  
Dipole Field ◽  
Wave Frequency ◽  
Alfven Wave ◽  
Inertial Waves ◽  
Axial Dipole ◽  
Wide Range ◽  
The Magnetic Field

<p>It is known that the columnar structures in rapidly rotating convection are affected by the magnetic field in ways that enhance their helicity. This may explain the dominance of the axial dipole in rotating dynamos. Dynamo simulations starting from a small seed magnetic field have shown that the growth of the field is accompanied by the excitation of convection in the energy-containing length scales. Here, this process is studied by examining axial wave motions in the growth phase of the dynamo for a wide range of thermal forcing. In the early stages of evolution where the field is weak, fast inertial waves weakly modified by the magnetic field are abundantly present. As the field strength(measured by the ratio of the Alfven wave to the inertial wave frequency) exceeds a threshold value, slow magnetostrophic waves are spontaneously generated. The excitation of the slow waves coincides with the generation of helicity through columnar motion, and is followed by the formation of the axial dipole from a chaotic, multipolar state. In strongly driven convection, the slow wave frequency is attenuated, causing weakening of the axial dipole intensity. Kinematic dynamo simulations at the same parameters, where only fast inertial waves are present, fail to produce the axial dipole field. The dipole field in planetary dynamos may thus be supported by the helicity from slow magnetostrophic waves.</p>

scholarly journals Why and How to Switch to Genomic Selection: Lessons From Plant and Animal Breeding Experience

2021 ◽  
Vol 12 ◽  
Author(s):  
◽  
Aline Fugeray-Scarbel ◽  
Catherine Bastien ◽  
Mathilde Dupont-Nivet ◽  
Stéphane Lemarié
Keyword(s):  
Genetic Diversity ◽  
Genomic Selection ◽  
Plant Species ◽  
Animal Species ◽  
Animal Breeding ◽  
Breeding Cycle ◽  
Breeding Programs ◽  
The Third ◽  
Wide Range ◽  
Selection For

The present study is a transversal analysis of the interest in genomic selection for plant and animal species. It focuses on the arguments that may convince breeders to switch to genomic selection. The arguments are classified into three different “bricks.” The first brick considers the addition of genotyping to improve the accuracy of the prediction of breeding values. The second consists of saving costs and/or shortening the breeding cycle by replacing all or a portion of the phenotyping effort with genotyping. The third concerns population management to improve the choice of parents to either optimize crossbreeding or maintain genetic diversity. We analyse the relevance of these different bricks for a wide range of animal and plant species and sought to explain the differences between species according to their biological specificities and the organization of breeding programs.

scholarly journals The Culture of the Sakas of Semirechye: Contemporary State and Current Issues of Study

2021 ◽  
Vol 20 (3) ◽  
pp. 22-35
Author(s):  
Ernar A. Estemesov
Keyword(s):  
Iron Age ◽  
Social Groups ◽  
Archaeological Sites ◽  
Radiocarbon Dates ◽  
Funeral Rites ◽  
The Third ◽  
Urgent Task ◽  
Wide Range ◽  
Burial Mounds ◽  
Second Category

Purpose. The article describes the history and analysis of the main issues in the study of archaeological sites of the Saka period in Semirechye. They are presented by three main types on this territory: burial and memorial complexes, settlements and hoards. The first type of monuments includes numerous burial mounds, where the elite burials of “royal” type and ordinary burials are located. Both social groups are combined by the unity of funeral rites, and the main differences are the complexity of architecture, memorial practices, and richness of burial equipment in the “royal” type burial mounds. The second category of monuments is presented by the settlements that are mostly small in size. The constructions like half dugouts were discovered on them, which gave a rich ceramic material. The third type of monuments of the Saka period in Semirechye includes numerous hoards of bronze items. Some of them are represented by the cult objects (sacrificial tables, lamps and cauldrons) that mark the places of worship. A significant percentage of the hoards contain items of weapons, horse equipment and household purposes and, apparently, serve as offerings to the spirits. However, despite the considerable progress in the study of the Saka monuments of the Semirechye Region, the main problem is their cultural attribution at this time. Some researchers suggest that the independent Saka archaeological culture was formed and developed on the territory of Semirechye in the Early Iron Age, while others believe that the Saka monuments of this region belong to the broader historical and cultural community that also covers the neighboring regions of Kyrgyzstan and Xinjiang. Results Another important issue in the study of the Saka sites of Semirechye is to clarify the chronology of burial and memorial complexes. Up to now, the significant database of radiocarbon dates has been accumulated, which allows us to consider the chronological positions of a wide range of monuments in a new way. It was of great importance to obtain such dates from several burials of Karatuma necropolis, which showed that it belonged to the Saka period, since burial monuments of this appearance are traditionally dated back to the Wusun period. Conclusion. The necessity of solution of these problems is an urgent task for further research of burial and settlement objects of the Saka period in this region.

scholarly journals Perancangan dan Analisis Perbandingan Implementasi OSPF pada Jaringan IPv4 dan IPv6

2014 ◽  
Vol 2 (1) ◽  
pp. 40
Author(s):  
PAULINE RAHMIATI ◽  
DWI ARYANTA ◽  
TAUFIQ AGUNG PRIYADI
Keyword(s):  
Network Design ◽  
Shortest Path ◽  
Routing Protocol ◽  
Convergence Time ◽  
The Third ◽  
Wide Range ◽  
Packet Tracer ◽  
Maximum Limit ◽  
Better Than

ABSTRAKOSPF (Open Shortest Path First) adalah suatu routing protokol bersifat terbuka dan didukung oleh berbagai perangkat network. IPv4 telah mencapai batas maksimum dalam jumlah alamat sehingga IPv6 merupakan solusi dalam hal tersebut. Seperti IPv4, IPv6 juga sudah mulai diimplementasikan untuk routing protokol OSPF, oleh karena itu pada penelitian ini akan dirancang suatu routing protokol OSPF IPv6 dan sebagai bahan perbandingan akan dibandingkan dengan OSPF IPv4. Software Cisco Packet Tracer 5.3 digunakan untuk mensimulasikan perancangan jaringan yang dibuat. Pada penelitian ini akan dibandingkan 2 buah jaringan berbasis routing protokol OSPF, yaitu OSPF untuk IPv4 dan IPv6. Skenario pertama dilakukan 100 kali dalam 5 kasus untuk mengetahui nilai delay OSPF IPv4 dan OSPF IPv6. Skenario kedua dilakukan pemutusan link dilakukan sebanyak 30 kali, hal yang dilihat dari pengujian ini adalah hasil trace route dari cost yang ada. Skenario ketiga dilakukan dengan mengamati waktu konvergensi dari OSPF IPv4 dan IPv6. Secara keseluruhan nilai delay OSPF IPv6 lebih kecil dibandingkan dengan OSPF IPv4 sebesar 3-6%, Trace route dan nilai cost pada OSPF IPv6 dan OSPF IPv4 sama tetapi nilai delay OSPF IPv6 lebih kecil sebesar 3-6% dan waktu konvergensi OSPF IPv4 bernilai sama dengan OSPF IPv6 yaitu 10 detik.Kata kunci: OSPF, IPv4, Ipv6, delay, konvergensiABSTRACTOSPF (Open Shortest Path First) is a routing protocol that opened and supported by a wide range of network devices. IPv4 has reached the maximum limit on the number of addresses that IPv6 are a solution in this case. Same as IPv4, IPv6 also has begun to be implemented for the OSPF routing protocol, therefore this study wiould design an IPv6 OSPF routing protocol and as a comparison will be compared to IPv4 OSPF. Cisco Packet Tracer 5.3 software was used to simulate the made network design. This research would compare two pieces of network-based routing protocol OSPF, OSPF for IPv4 and IPv6. The first scenario was done 100 times in of 5 cases to determine the value of delay OSPF OSPF IPv4 and IPv6. The second scenario was carried out link terminations 30 times, it was seen from the tests was the result of trace route from the existing cost. The third scenario was done by observed at the convergence time of OSPF IPv4 and IPv6. The overall delay value OSPF IPv6 better than IPv4 OSPF by 3-6%, the trace route and the OSPF cost value of IPv6 and IPv4 OSPF were same but delay OSPF IPv6 was better 3-6% and convergence time was the same as IPv4 OSPF OSPF IPv6 as 10 seconds.Keywords: OSPF, IPv4, IPv6, delay, convergence

Synthesis and third-order nonlinear optical properties of novel ethynyl-linked heteropentamer composed of four porphyrins and one pyrene

2009 ◽  
Vol 13 (02) ◽  
pp. 275-282 ◽  
Author(s):  
Ning Sheng ◽  
Jing Sun ◽  
Yongzhong Bian ◽  
Jianzhuang Jiang ◽  
Dong Xu
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Three Dimensional ◽  
Spectroscopic Methods ◽  
Third Order ◽  
Zinc Compounds ◽  
Nlo Properties ◽  
Metal Free ◽  
The Third ◽  
Wide Range

Novel heteropentameric porphyrins-pyrene arrays, in which four meso-tetraphenyl porphyrins are linked to the center unit of pyrene by four acetylenyl bonds, were designed and synthesized. The newly synthesized heteropentameric compounds have been characterized by a wide range of spectroscopic methods. The third-order nonlinear optical (NLO) properties of both the metal-free and zinc compounds of the three-dimensional arrays were investigated by Z-scan experiments, showing enhanced NLO properties compared with that of the porphyrin and pyrene monomers.

Solvent-Induced Damage in Polyimide Thin Films

1989 ◽  
Vol 167 ◽  
Author(s):  
M. S. Hu
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Exposure Time ◽  
Critical Strain ◽  
Threshold Value ◽  
Weak Dependence ◽  
Polyimide Films ◽  
Band Formation ◽  
Enhanced Diffusion ◽  
Wide Range

AbstractSolvent induced damage bands formed in residually strained polyimide thin films on different substrates have been studied. Microscopy studies have shown that these bands resemble crazes. A mechanics approach Is taken to understand the band formation phenomenon.The critical strain for damage formation has been identified. This strain decreases with increase in exposure time, but always exhibits a threshold value. In contrast to the cracking of brittle films, the critical strain has only a weak dependence on the film thickness over a wide range. This behavior obtains because the crazing of the polyimide films is nucleation controlled. Strain-enhanced diffusion of solvent into the films is considered to be responsible for the property degradation that leads to damage formation.

Detection of cancer signal for over 50 AJCC cancer types with a multi-cancer early-detection test.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3072-3072
Author(s):  
Habte Aragaw Yimer ◽  
Wai Hong Wilson Tang ◽  
Mohan K. Tummala ◽  
Spencer Shao ◽  
Gina G. Chung ◽  
...  
Keyword(s):  
Machine Learning ◽  
Early Detection ◽  
Cancer Type ◽  
Anatomic Site ◽  
The Third ◽  
Cancer Early Detection ◽  
Wide Range ◽  
Source Data ◽  
Cancer Types

3072 Background: The Circulating Cell-free Genome Atlas study (CCGA; NCT02889978) previously demonstrated that a blood-based multi-cancer early detection (MCED) test utilizing cell-free DNA (cfDNA) sequencing in combination with machine learning could detect cancer signals across multiple cancer types and predict cancer signal origin. Cancer classes were defined within the CCGA study for sensitivity reporting. Separately, cancer types defined by the American Joint Committee on Cancer (AJCC) criteria, which outline unique staging requirements and reflect a distinct combination of anatomic site, histology and other biologic features, were assigned to each cancer participant using the same source data for primary site of origin and histologic type. Here, we report CCGA ‘cancer class’ designation and AJCC ‘cancer type’ assignment within the third and final CCGA3 validation substudy to better characterize the diversity of tumors across which a cancer signal could be detected with the MCED test that is nearing clinical availability. Methods: CCGA is a prospective, multicenter, case-control, observational study with longitudinal follow-up (overall population N = 15,254). Plasma cfDNA from evaluable samples was analyzed using a targeted methylation bisulfite sequencing assay and a machine learning approach, and test performance, including sensitivity, was assessed. For sensitivity reporting, CCGA cancer classes were assigned to cancer participants using a combination of the type of primary cancer reported by the site and tumor characteristics abstracted from the site pathology reports by GRAIL pathologists. Each cancer participant also was separately assigned an AJCC cancer type based on the same source data using AJCC staging manual (8th edition) classifications. Results: A total of 4077 participants comprised the independent validation set with confirmed status (cancer: n = 2823; non-cancer: n = 1254 with non-cancer status confirmed at year-one follow-up). Sensitivity was reported for 24 cancer classes (sample sizes ranged from 10 to 524 participants), as well as an “other” cancer class (59 participants). According to AJCC classification, the MCED test was found to detect cancer signals across 50+ AJCC cancer types, including some types not present in the training set; some cancer types had limited representation. Conclusions: This MCED test that is nearing clinical availability and was evaluated in the third CCGA substudy detected cancer signals across 50+ AJCC cancer types. Reporting CCGA cancer classes and AJCC cancer types demonstrates the ability of the MCED test to detect cancer signals across a set of diverse cancer types representing a wide range of biologic characteristics, including cancer types that the classifier has not been trained on, and supports its use on a population-wide scale. Clinical trial information: NCT02889978.

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