Multiple-frequency synchronization of the four exciters in a far super-resonant vibrating system with an isolation frame

Generally, the synchronization studies on two or multiple exciters are preconditioned by being a single frequency, while the multiple-frequency synchronization problems in a vibrating system, including double-frequency and triple-frequency, are less considered, which are also very significant in engineering. This paper attempts to solve this issue by considering a dynamical model with an isolation frame, driven by the four exciters. The synchronization for the four exciters and its stability under the double-frequency and triple-frequency conditions are studied in detail. Firstly, the mathematical modeling of the system is established, and the corresponding motion differential equations are derived. Using the asymptotic method and the average method, yields the theoretical condition of implementing multiple-frequency synchronization, and the theoretical condition for stability of the system complies with the Routh–Hurwitz criterion. The dynamic characteristics of the system, including stable phase differences, stability abilities, responses of the system, and relative motion relationship, are qualitatively discussed by numeric. Finally, simulations are performed by applying a Runge–Kutta program to validate the theoretical and numerical qualitative results. It is shown that, by reasonably matching the key parameters of the system, the stronger, stable, and valuable motion states of vibrating machines, including vibration amplitudes, frequencies, and motion trajectory, can be realized, which are exactly the desires in engineering.

The B-topology on S ∗-doubly quasicontinuous posets

The notions of o s {o}_{s} -convergence and S ∗ {S}^{\ast } -doubly quasicontinuous posets are introduced, which can be viewed as common generalizations of Birkhoff’s order-convergence and S ∗ {S}^{\ast } -doubly continuous posets, respectively. We first consider the relationship between o s {o}_{s} -convergence and B-topology and show that the topology induced by o s {o}_{s} -convergence according to the standard topological approach is the B-topology precisely. Then, the topological characterization for the S ∗ {S}^{\ast } -doubly quasicontinuity is presented. It is proved that a poset is S ∗ {S}^{\ast } -doubly quasicontinuous iff the poset equipped with the B-topology is locally hyperclosed iff the lattice of all B-open subsets of the poset is hypercontinuous. Finally, the order theoretical condition for the o s {o}_{s} -convergence being topological is given and the complete regularity of B-topology on S ∗ {S}^{\ast } -doubly quasicontinuous posets is explored.

Polynomial dissipativity of proportional delayed BAM neural networks

This paper pays close attention to the global polynomial dissipativity (GPD) for proportional delayed BAM neural networks (PDBAMNNs). The global exponential dissipativity (GED) and the global dissipativity (GD) are also talked about. Under the help of novel Lyapunov functionals and a generalized Halanay inequality, a set of dissipative criteria for such systems are led out, together with the global polynomial attracting set (GPAS) and the global attracting set (GAS). Further, the relationship among GPD, GED and GD is unveiled. Finally, a proposed theoretical condition is validated through a simulation experiment.

Changes of political theories in the countries of Central and Eastern Europe

In the countries of Middle and Eastern Europe the collapse of „real socialism” was followed by the annulment of political and ideological supervision over scientific researches. Since then the political theory has been developing in an unembarrassed way, drawing investigative patterns with the tradition of western political sciences. Form this perspective, the expression „westernization” used with regard to political theory signifies the process of going away from Marxism and historical materialism. The article focuses on two essential trends of this process. The main consequence is the pluralization of theoretical bases of investigations, which signifies not only differentation, but also the lack of predominant theory. The international program for monitoring the development since 1990, shows that new investigative trends disclose a division between the traditional and current model of politology, which demonstrates the topicality of arguments raised in western academic debatesover the theoretical condition and status of political science discipline.

A Decision Optimization Model for Leased Manufacturing Equipment with Warranty under Forecasting Production/Maintenance Problem

Due to the expensive production equipment, many manufacturers usually lease production equipment with a warranty period during a finite leasing horizon, rather than purchasing them. The lease contract contains the possibility of obtaining an extended warranty for a given additional cost. In this paper, based on the forecasting production/maintenance optimization problem, we develop a mathematical model to study the lease contract with basic and extended warranty based on win-win relationship between the lessee and the lessor. The influence of the production rates in the equipment degradation consequently on the total cost by each side during the finite leasing horizon is stated in order to determine a theoretical condition under which a compromise-pricing zone exists under different possibilities of maintenance policies.

State Gun Policy and Cross-State Externalities: Evidence from Crime Gun Tracing

This paper provides a theoretical and empirical analysis of cross-state externalities associated with gun regulations that impact gun trafficking. Using tracing data, which identify the source state for crime guns recovered in destination states, we find that firearms tend to flow from states with weak laws to states with strict laws, satisfying a key theoretical condition for the existence of externalities. We also find that gun flows are more significant between nearby states, suggesting that externalities are spatial in nature. Finally, we present evidence that criminal possession of guns is higher in states exposed to weak laws in nearby states. (JEL H76, K14, K42)