Pebble games were originally formulated to study time-space tradeoffs in computation, modeled by games played on directed acyclic graphs (DAGs). Close connections between pebbling and cryptography have been known for decades. A series of recent research starting with (Alwen and Serbinenko, STOC 2015) has deepened our understanding of the notion of memory-hardness in cryptography— a useful prope...

background and purpose: managers’ competencies leave a decisive effect on the mental health of staff. the present research intends to investigate the influence of emotional-social competencies on the mental health of the staff. method: the current research is practical in its purpose and correlative regarding data gathering. the statistical community included all the staff of pegah company in d...

We study the isomorphic implication problem for Boolean constraints. We show that this is a natural analog of the subgraph isomorphism problem. We prove that, depending on the set of constraints, this problem is in P, NP-complete, or NP-hard, coNP-hard, and in P || . We show how to extend the NP-hardness and coNP-hardness to P || -hardness for some cases, and conjecture that this can be done in...

In this lecture, we first examine several classes of NP-hardness and polynomial time algorithms which arise from differences in how integers are encoded in problem input. We then look at the 3-partition problem, which is very useful for proving the strongest notion of NP-hardness. Finally, we use reduction from 3-partition to prove NP-hardness for a handful of problems, including a set of 4 pac...

I. The Knoop test of hardness of materials has been used to test the hardness of human nail. 2. The range of hardness of nails was found to be small in healthy persons and large in malnourished children. 3. Nails from malnourished children were in general much harder than those from healthy persons. The nails of a small group of three children became softer while they were recovering from malnu...

A simplified model of the hardness kernel, hð~r ; ~r 0Þydð~r K~r 0Þ, has been evaluated for the calculation of the global hardness in a series of Lewis acids and bases using the MP2 method. It is found that this simple model yields the appropriate ordering of the molecules according to their hardness values when compared to experimental available results. q 2005 Elsevier B.V. All rights reserved.

The freshwater fingerlings of Cirrhinus mrigala were exposed to Nickel in acidic medium pH = 6.0 (5.8-6.2), alkaline medium pH = 9.0 (8.8-9.2) and water hardness (40 mg/l) of CaCO3. The study indicates that nickel accumulation was significantly influenced by pH and hardness of water The concentration was found to be significantly higher at pH = 9.0 than at pH = 6.0. Also the presence of hardnes...

A hardness-based model for tailor hardened boron steel is presented that takes into account the softened heat-affected zone of resistance spot welds. The computational model is designed for crashworthiness simulation of fully and partially hardened components obtained by tailored tooling. Five different hardness grades of 22MnB5 are used for model calibration. The proposed model is validated wi...

D. Dobrotă, C. Iancu, Engineering Faculty, “Constantin Brâncuşi” University of Târgu-Jiu, Romania This paper presents the results of the main changes in the chemical composition of the material, and changes in its hardness. The changes in terms of chemical composition refer primarily to changes in concentration of sulfur and carbon, and in terms of hardness material change there can be noticed ...