External capacitive probes for the nondestructive determination of the dielectric properties of polymeric materials

The effect of the finite dimensions of the test object on the results of nondestructive determination of the dielectric properties of polymers with external capacitive probes has been investigated. Recommendations are made for eliminating the effect of the air gap between the electrodes and the surface of the test object.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1098–1104, November–December, 1969.     

Zero dielectric constant limit to the non-isentropic compressible Euler-Maxwell system

We investigate the zero dielectric constant limit to the non-isentropic compressible Euler-Maxwell system.We justify this singular limit rigorously in the framework of smooth solutions and obtain the nonisentropic compressible magnetohydrodynamic equations as the dielectric constant tends to zero.     

A prognosis model for wear prediction based on oil-based monitoring

This paper reports on the development of a wear prediction model based on stochastic filtering and hidden Markov theory. It is assumed that observations at discrete time points are available such as metal concentrations from oil-based monitoring, which are related to the true underlying state of the system which is unobservable. The system state is represented by a generic term of wear which is modelled by a continuous hidden Markov Chain using a Beta distribution. We formulated a recursive model to predict the current and future system state given past observed monitoring information to date. The model is useful to wear-based monitoring such as oil analysis. Numerical examples are presented in the paper based on simulated and real data.     

Fault diagnosis system based on fuzzy-inference

Aimed at deficiencies of the traditional fault diagnosis method for pneumatic press, an automatic fault diagnosis system is established and its purpose including improvement of preferment and precision was experimented. First, the fuzzy inference algorithm is analyzed. Then the fuzzy relationship between the fault symptom and the fault cause is compared. Finally, the paper takes the pneumatic press as an example, and established a fast and efficient fault diagnosis system based on fuzzy inference. The practical test results show that the accuracy of fault diagnosis and forecast is improved, and the fuzzy reference algorithm can satisfy the system requirements of security and stabilization as well as higher precision and rapid speed.     

A flow model based on polylinking system

We extend recent work on nonlinear optimal control problems with integer restrictions on some of the control functions (mixed-integer optimal control problems, MIOCP). We improve a theorem (Sager et?al. in Math Program 118(1): 109–149, 2009) that states that the solution of a relaxed and convexified problem can be approximated with arbitrary precision by a solution fulfilling the integer requirements. Unlike in previous publications the new proof avoids the usage of the Krein-Milman theorem, which is undesirable as it only states the existence of a solution that may switch infinitely often. We present a constructive way to obtain an integer solution with a guaranteed bound on the performance loss in polynomial time. We prove that this bound depends linearly on the control discretization grid. A numerical benchmark example illustrates the procedure. As a byproduct, we obtain an estimate of the Hausdorff distance between reachable sets. We improve the approximation order to linear grid size h instead of the previously known result with order ${\sqrt{h}}$ (H?ckl in Reachable sets, control sets and their computation, augsburger mathematisch-naturwissenschaftliche schriften. Dr. Bernd Wi?ner, Augsburg, 1996). We are able to include a Special Ordered Set condition which will allow for a transfer of the results to a more general, multi-dimensional and nonlinear case compared to the Theorems in Pietrus and Veliov in (Syst Control Lett 58:395–399, 2009).     

A universal compiler system based on production rules

This paper describes a compiler system which makes use of production rules for the translation. The source language syntax is defined in terms of a phrase structure grammar. Semantic rules are provided by an extension of the production rules, and special symbols are introduced for this purpose. Recognition of symbol strings is facilitated by a special syntactic filter routine. An example of a simple macro compiler is given to illustrate the basic concepts of the system.     

Dynamic monitoring and control of software project effort based on an effort buffer

The improvement to the monitoring and control efficiency of software project effort is a challenge for project management research. We propose to overcome this challenge through the use of a model for the buffer determination and monitoring of software project effort. This software project effort buffer was originally determined on the basis of a risk management factor analysis with total consideration for project managers’ risk preference. The effort buffer was next allocated to different stages according to the buffer allocation cardinal. An effort deviation monitoring and control model was then established based on the grey prediction model, including the establishment of a deviation monitoring and control model, a simulation test of the accuracy and the deviation prediction algorithm flow chart. The method system was eventually applied to an actual project and compared with the actual project data. The results show that the relative error test accuracy of the proposed model is qualified according to the test standard of the grey model, signifying that it could be used for the prediction of effort deviation and decision-making. The proposed model could use the dynamic control system to monitor and control software project effort in an effective manner.     

Public-key cryptographic system based on generalized satisfiability problem

In the modern world, a considerable part of information is processed in electronic form. The necessity of protection of this information during its transmission over open communication channels has led to widespread of public-key cryptographic systems based on different NP-complete problems. In this article, the realization of an asymmetric cryptosystem based on an NP-complete S-satisfiability problem is studied.     

A cryptographic system based on finite field transforms

In this paper, we develop a cipher system based on finite field transforms. In this system, blocks of the input character-string are enciphered using congruence or modular transformations with respect to either primes or irreducible polynomials over a finite field. The polynomial system is shown to be clearly superior to the prime system for conventional cryptographic work.     

基于小波包分解的非线性时变系统辩识

在实际应用中,经常会碰到非线性时变系统,它们的辨识和建模比较困难．本文采用时变Hammerstein模型描述时变非线性系统．该模型可以以较简单的方式刻划系统的时变特性和非线性特性．然后用小波包对时变系数进行展开,把时变系统的辨识转化为对时不变系数的辨识．     

Vehicle dispatching system based on Taguchi-tuned fuzzy rules

This paper presents the development of a dispatching system for a fleet of automated guided vehicles in a flexible manufacturing environment which is based on a hybrid Fuzzy–Taguchi approach. A fuzzy decision-making system emulates the human behavior necessary for multi-objective directed decision making in a dynamically evolving environment. A statistical approach based on the Taguchi method tunes the fuzzy rules to achieve near optimal performance. Simulation results demonstrate the effectiveness of this marriage of computational tools in dealing with the well-known NP-complete scheduling problem.     

Optimizing monitoring time in a continuous-review cyclic inventory system

This paper discusses a mathematical model for controlling amonitoring time by a sensing device in a continuous-review cyclicinventory system. The level of the inventory is monitored bythe sensor for a continuous period, whether the stock runs outor not. First, we consider the case where the lifetime of commoditiesis finite. It is shown that, under certain conditions, thereexists a finite and unique optimal monitoring time minimizingthe long-run average cost. Secondly, we discuss the case wherethe lifetime is infinite, with an appropriately modified restockingpolicy, and obtain an equation for the optimal monitoring timeunder milder conditions. Finally, some numerical examples arepresented, and sensitivity analyses for the optimal policiesare carried out.     

Weak solutions to a non-linear hyperbolic system arising in the theory of dielectric liquids

We consider a model of the motion of a viscous dielectric liquid subjected to a DC electric field in the case when the bulk conduction results from the presence of a dissociation-recombination process. The effects of both magnetic field and ionic diffusion are neglected. The existence of at least one weak solution is proved via the method of renormalized solutions.     

On a phase-field system based on the Cattaneo law

Our aim in this paper is to study a generalization of the Caginalp phase-field system based on the Maxwell-Cattaneo law for heat conduction and endowed with Neumann boundary conditions. In particular, we obtain well-posedness results and study the dissipativity of the associated solution operators. We also prove, when the enthalpy is conserved, the existence of the global attractor. We finally study the spatial behavior of solutions in a semi-infinite cylinder, assuming that such solutions exist and have a proper (spatial) decay at infinity.     

Fuzzy Bayesian system reliability assessment based on exponential distribution

The Bayesian system reliability assessment under fuzzy environments is proposed in this paper. In order to apply the Bayesian approach, the fuzzy parameters are assumed as fuzzy random variables with fuzzy prior distributions. The (conventional) Bayesian estimation method will be used to create the fuzzy Bayes point estimator of system reliability based on Exponential distribution by invoking the well-known theorem called “Resolution Identity” in fuzzy sets theory. On the other hand, we also provide the computational procedures to evaluate the membership degree of any given Bayes point estimate of system reliability. In order to achieve this purpose, we transform the original problem into a nonlinear programming problem. This nonlinear programming problem is then divided into four subproblems for the purpose of simplifying computation. Finally, the subproblems can be solved by using any commercial optimizers, e.g., GAMS or LINGO (LINDO).     

A polarisation based approach to model strain dependent electrostatic pressure of dielectric elastomer actuators

A wide-spread lumped parameter model describing the electrostatic pressure is presented by Pelrine et. al. in 1998 [1]. In Pelrine's model, the electrostatic pressure is affected by the relative permittivity of the material, also known as dielectric constant. However, many researchers found that the dielectric constant of DEAs is not constant at all, but decreasing with increasing pre-stretch of the material. In this work, an alternative modelling approach is presented, explaining the stretch dependent actuation pressure. It is shown that this new model fits experimental data found in literature quite well. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Lag synchronizing chaotic system based on a single controller

Lag synchronization of chaotic system is investigated. Three kinds of schemes are proposed to lag synchronize Chen chaotic system. All the three schemes need only a single controller to realize lag synchronization. Especially in the last two schemes, only one state variable is contained in controller, which is of important significance on using chaos lag synchronization for applications. Finally numerical simulations are provided to show the effectiveness of the developed methods.