scholarly journals On linear-size pseudorandom generators and hardcore functions

2014 ◽  
Vol 554 ◽  
pp. 50-63 ◽  
Author(s):  
Joshua Baron ◽  
Yuval Ishai ◽  
Rafail Ostrovsky
Keyword(s):  
Linear Size ◽  
Pseudorandom Generators ◽  
Hardcore Functions

Improving the efficiency of hardening of tillage machine working bodies by arc surfacing using wear-resistant rollers

2020 ◽  
pp. 176-185
Author(s):  
Dmitriy B. Slinko ◽  
Vyacheslav A. Denisov ◽  
Dmitriy A. Dobrin ◽  
Andrey V. Afanas’yev ◽  
Pavel M. Kislov
Keyword(s):  
Wear Resistance ◽  
Operating Time ◽  
Field Tests ◽  
Electric Arc ◽  
Cutting Edge ◽  
Linear Size ◽  
Research Purpose ◽  
Cored Wire ◽  
Wear Resistant ◽  
Working Bodies

Reducing operating costs during soil processing and increasing the wear resistance of parts and components is an important condition for reducing the cost of agricultural products, increasing its efficiency and competitiveness. The development of materials with increased wear resistance and new effective technologies for strengthening working bodies in their manufacture is now becoming an urgent task. (Research purpose) The research purpose is increasing the wear resistance of the working bodies of soil-processing machines by electric arc surfacing. (Materials and methods) During the experimental study, it has been performed testing of modes and surfacing of a pilot batch of working bodies from Kverneland for field tests in VIM on an automated installation for electric arc surfacing. Authors used eutectic CastolinEnDotec DO*30 powder wire with a diameter of 1.2 millimeters and a boron content of up to 4 percent for surfacing wear-resistant rollers, which allows to obtain wear-resistant rollers with a hardness of up to 65 HRC without pores and cracks. (Results and discussion) It has been revealed that hardened ploughshares that have passed field tests are subject to lower wear rates compared to non-hardened ones. It was found that when operating time is 24.785 hectares per ploughshare, the wear of the linear size of the cutting edge along the width of hardened ploughshares is on average up to 10-11 millimeters less than that of non-hardened ones. It was found that when processing 228 hectares, the wear of the linear size of the cutting edge along the width of hardened bits is on average up to 9-10 millimeters less than that of non-hardened ones. (Conclusions) The technology of surfacing with intermittent wear-resistant rollers provides an increase in the efficiency of hardening of Kverneland working bodies according to the criterion of wear resistance by an average of 20-30 percent. The adjusted technological parameters of the surfacing process will reduce the wear rate and increase the service life of the blade part of the working bodies, as well as reduce the amount of surfaced material by an average of 60 percent. The continuation of work on strengthening the working bodies should be aimed at changing the surfacing scheme and choosing a cheaper domestic cored wire.

Pseudorandom Generators for Combinatorial Shapes

2013 ◽  
Vol 42 (3) ◽  
pp. 1051-1076 ◽  
Author(s):  
Parikshit Gopalan ◽  
Raghu Meka ◽  
Omer Reingold ◽  
David Zuckerman
Keyword(s):  
Pseudorandom Generators

scholarly journals Prognostic impact of macrometastasis linear size in sentinel node biopsy for breast carcinoma

2017 ◽  
Vol 43 (8) ◽  
pp. 1421-1427
Author(s):  
M.P. Foschini ◽  
R. Miglio ◽  
C. Quinn ◽  
B. Belgio ◽  
P. Regitnig ◽  
...  
Keyword(s):  
Breast Carcinoma ◽  
Sentinel Node ◽  
Sentinel Node Biopsy ◽  
Linear Size ◽  
Prognostic Impact ◽  
Node Biopsy

scholarly journals A Mathematical Problem for Security Analysis of Hash Functions and Pseudorandom Generators

2015 ◽  
Vol 26 (02) ◽  
pp. 169-194 ◽  
Author(s):  
Koji Nuida ◽  
Takuro Abe ◽  
Shizuo Kaji ◽  
Toshiaki Maeno ◽  
Yasuhide Numata
Keyword(s):  
Mathematical Problem ◽  
Security Analysis ◽  
Hash Functions ◽  
Future Research ◽  
Theoretical Frameworks ◽  
Pseudorandom Generators ◽  
Mathematical Problems ◽  
Security Evaluations ◽  
Security Property ◽  
Provably Secure

In this paper, we specify a class of mathematical problems, which we refer to as “Function Density Problems” (FDPs, in short), and point out novel connections of FDPs to the following two cryptographic topics; theoretical security evaluations of keyless hash functions (such as SHA-1), and constructions of provably secure pseudorandom generators (PRGs) with some enhanced security property introduced by Dubrov and Ishai (STOC 2006). Our argument aims at proposing new theoretical frameworks for these topics (especially for the former) based on FDPs, rather than providing some concrete and practical results on the topics. We also give some examples of mathematical discussions on FDPs, which would be of independent interest from mathematical viewpoints. Finally, we discuss possible directions of future research on other crypto-graphic applications of FDPs and on mathematical studies on FDPs themselves.

scholarly journals Complexity of Nondeterministic Functions

1994 ◽  
Vol 1 (2) ◽  
Author(s):  
Alexander E. Andreev
Keyword(s):  
Upper Bound ◽  
Randomized Algorithms ◽  
Nonempty Intersection ◽  
Linear Size ◽  
Worst Case ◽  
K Value ◽  
Hitting Set ◽  
Set Size

The complexity of a nondeterministic function is the minimum possible complexity of its determinisation. The entropy of a nondeterministic function, F, is minus the logarithm of the ratio between the number of determinisations of F and the number of all deterministic functions.<br /> <br />We obtain an upper bound on the complexity of a nondeterministic function with restricted entropy for the worst case.<br /> <br /> These bounds have strong applications in the problem of algorithm derandomization. A lot of randomized algorithms can be converted to deterministic ones if we have an effective hitting set with certain parameters (a set is hitting for a set system if it has a nonempty intersection with any set from the system).<br /> <br />Linial, Luby, Saks and Zuckerman (1993) constructed the best effective hitting set for the system of k-value, n-dimensional rectangles. The set size is polynomial in k log n / epsilon.<br /> <br />Our bounds of nondeterministic functions complexity offer a possibility to construct an effective hitting set for this system with almost linear size in k log n / epsilon.

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