scholarly journals A monomial cycle basis on Koszul homology modules

2008 ◽  
Vol 212 (1) ◽  
pp. 132-139 ◽  
Author(s):  
Dorin Popescu
Keyword(s):  
2020 ◽  
pp. 491-495
Author(s):  
A.M. Tomashevich ◽  
G.G. Shirvan’yants ◽  
D.A. Teryaev

The possibility of life and reliability enhancing of AL-31F low pressure turbine disc’s fir-tree slots by ultrasonic hardening is considered. Having disc’s material properties studied, working stress derivation is executed which was further used for following comparative fatigue tests. Also, Davidenkov method residual stress analysis is carried out which showed 95.3 % change to compression stress for circumferential residual stress and 80.9 % change to compression stress for axial residual stress which proves possibility of fir-tree slots’ life and reliability enhancement by ultrasonic hardening. Comparative fatigue tests with N = 4•10 5 cycles basis showed that the hardened samples standing out the cycle basis during higher oscillatory amplitudes (and, thus, affecting loads) than the non-hardened basic ones.


2018 ◽  
Vol 28 (13) ◽  
pp. 1850165
Author(s):  
Débora C. Corrêa ◽  
David M. Walker ◽  
Michael Small

The properties of complex networks derived from applying a compression algorithm to time series subject to symbolic ordinal-based encoding is explored. The information content of compression codewords can be used to detect forbidden symbolic patterns indicative of nonlinear determinism. The connectivity structure of ordinal-based compression networks summarized by their minimal cycle basis structure can also be used in tests for nonlinear determinism, in particular, detection of time irreversibility in a signal.


2005 ◽  
Vol 15 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Leo Liberti ◽  
Edoardo Amaldi ◽  
Francesco Maffioli ◽  
Nelson Maculan

The problem of finding a fundamental cycle basis with minimum total cost in a graph arises in many application fields. In this paper we present some integer linear programming formulations and we compare their performances, in terms of instance size, CPU time required for the solution, and quality of the associated lower bound derived by solving the corresponding continuous relaxations. Since only very small instances can be solved to optimality with these formulations and very large instances occur in a number of applications, we present a new constructive heuristic and compare it with alternative heuristics.


2008 ◽  
Vol 38 (4) ◽  
pp. 1430-1447 ◽  
Author(s):  
Ramesh Hariharan ◽  
Telikepalli Kavitha ◽  
Kurt Mehlhorn
Keyword(s):  

1969 ◽  
Vol 51 (3) ◽  
pp. 565-573
Author(s):  
W. J. DAVIS

1. The dynamic properties of the intrasegmental swimmeret reflexes of the lobster Homarus americanus were studied by recording the discharge of the motor neurones while the swimmeret was moved sinusoidally in its natural arc over a wide range of frequencies. 2. The reflex responses of the excitor neurones of both powerstroke (retractor) and returnstroke (protractor) muscles display hysteresis. In both cases the efferent response corresponding to a given limb position is usually greater during imposed retraction than during protraction. 3. The cyclic efferent reflex response follows the sinusoidal movement stimulus at movement frequencies up to and beyond those which occur naturally during swimmeret beating, with no change in the position of maximum reflex activity in the cycle. The reflexes are therefore capable of influencing the motor output on a cycle-by-cycle basis. 4. The strength of the reflex response is maximum between 1 and 3 Hz. of imposed movement, and declines to either side of this range. The dynamic properties of the reflexes are therefore adjusted so that the maximum amplification of the rhythmic central motor command occurs at the natural frequency of swimmeret beating.


2019 ◽  
Vol 22 (1) ◽  
pp. 341-348
Author(s):  
Nir Druker ◽  
Gideon Goldwine ◽  
Eran Sher

We propose here a new method to evaluate the mixture charge density inside the combustion chamber of an internal combustion engine. This is an important parameter that is needed to optimize the spark timing and the amount of fuel that is introduced to the cylinder at each cycle, thus optimizing the engine operation for higher power, lower brake-specific fuel consumption, or lower pollutants’ emission at any altitude/ambient conditions. The evaluation of the charge density is performed at each cycle (on a cycle-to-cycle basis) by using the voltage–current characteristics of the spark plug gap. This real-time evaluation method may save two of the present in-use temperature and pressure gages, thus considerably increasing the reliability of the propulsion unit. Owing to the expected higher system reliability and system simplicity, small unmanned aerial vehicles, as well as small automotive engines of various types, may significantly benefit from this proposed method. The method principles, rationale, and some preliminary results are presented.


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