As one-more problems are widely used in both proving and analyzing the security of various cryptographic schemes, it is of fundamental importance to investigate the hardness of the one-more problems themselves. Bresson et al. (CT-RSA ’08) first showed that it is difficult to rely the hardness of some onemore problems on the hardness of their “regular” ones. Pass (STOC ’11) then gave a stronger ...

Nuclear stiffness, expressed as a hardness derivative, appears to be a good measure of the slope of global hardness. The authors analyze molecular states for which hardness has a maximum value. Maximum hardness principle (MHP) has been discussed. At the ground state hardness function does not obtain a maximum value versus spatial coordinates within a constant number of electrons (N), but is so ...

Algorithmic research strives to develop fast algorithms for fundamental problems. Despite its many successes, however, many problems still do not have very efficient algorithms. For years researchers have explained the hardness for key problems by proving NP-hardness, utilizing polynomial time reductions to base the hardness of key problems on the famous conjecture P 6= NP. For problems that al...

Method In order to identify the changes in the body the experiment was conducted by maintaining the standing posture for two hours by using three sorts of shoes state and four sorts of mats as an object of 9 test subjects. The Mat used in the experiment was designed on the basis of Elasticity 15% and 35%, Hardness 25Hs and 45Hs. As to the state of shoes, the experiment was progressed by dividin...

Hrušková M., Švec I. (2009): Wheat hardness in relation to other quality factors. Czech J. Food Sci., 27: 240–248. The analysis of the wheat hardness relation to other quality features was done with a set of 281 variety and commercial wheat samples, planted during the years of 2003–2006 in Central Bohemia and south Moravia areas. Technological quality was evaluated for grain, milling process, a...

The aim of this study was to evaluate the effect of the increase of energy density on Knoop hardness of Z250 and Esthet-X composite resins. Cylindrical cavities (3 mm in diameter X 3 mm in depth) were prepared on the buccal surface of 144 bovine incisors. The composite resins were bulk-inserted and polymerized using different light-curing units and times: conventional QTH (quartz-tungsten-halog...

INTRODUCTION Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). MATERIALS AND METHODS 40 samples of MCRs (Filtek Z...

It becomes a great challenge in the research area of metaheuristics to predict the hardness of combinatorial optimization problem instances for a given algorithm. In this study, we focus on the hardness of the traveling salesman problem (TSP) for 2-opt. In the existing literature, two approaches are available to measure the hardness of TSP instances for 2-opt based on the single objective: the ...

A measurement system is capable if it produces measurements with uncertainties small enough for demonstration of compliance with product specifications. To establish the capability of a system for Rock-well C scale hardness, one must assess measurement uncertainty and, when hardness is only an indicator, quantify the relation between hardness and the product property of real interest. The uncer...

Ever since the invention of Genetic Algorithms (GAs), researchers have put a lot of efforts into understanding what makes a function or problem instance hard for GAs to optimize. Many measures have been proposed to distinguish socalled GA-hard from GA-easy problems. None of these, however, has yet achieved the goal of being a reliable predictive GA-hardness measure. In this paper, we first pres...