Analysis of non-linear transmission lines by frequency domain perturbation method

We discuss a numerical method for solving non-linear transmission lines in the frequency domain. Such transmission lines are widely used for communications such as in GaAs integrated circuits and varactor diode circuits. The circuit equations are described by non-linear partial differential equations, so their analysis is very complicated compared with that of linear transmission lines. In this paper we propose a frequency-domain perturbation method for weakly non-linear transmission lines where the wave-forms are approximated by Fourier expansions and each frequency component is calculated by a modified perturbation method. To improve convergence, we introduce two new techniques, the compensation method and the homotopy method, which help to make the iteration stable and can be applied to a wide class of non-linear transmission lines. We have analysed shock wave phenomena in example. © 1997 by John Wiley & Sons, Ltd.     

Deadbeat Control with Disturbance Compensation Method and 1 MHz‐PLL for Single Phase Utility Interactive Inverter

In the near future, many distributed power systems will be connected to utility lines in the local area. The demand for control accuracy of utility interactive inverters will likely increase beyond present capabilities. The utility interactive inverter requires FRT capability to compensate for utility voltage fluctuations. A deadbeat control with disturbance compensation and 1 MHz‐PLL control with quasi‐dq transformation were applied to a utility interactive inverter using an FPGA based hardware controller. The FRT characteristics were verified through simulations and experiments, and the superior characteristics of the proposed method were verified.     

A Next‐Generation Distribution Automation System Using IEC 61850 GOOSE and Section Switches with Sensors

More and more dispersed power sources will be introduced to achieve a low‐carbon society. However, many problems may occur as a result of excessive introduction in the current power system. For example, delays or failures of fault detection may occur due to a decline in protective relay sensitivity. This paper proposes a new system of protective relays for distribution lines using section switches with sensors to solve the problem. In addition, experimental results on the proposed system composed of Intelligent Electronic Devices based on IEC 61850 are presented.     

DIAGNOSIS WITH THE CORRELATION INTEGRAL IN TIME DOMAIN

In this paper, a method to detect some kind of mechanical failures has been proposed. Based on the fact that any defect on the mechanical system would be inherently defined as statistical differences, we propose that the correlation exponents based on the Grassberger–Procaccia algorithm can be adopted as a diagnostic index. Chattering vibration during cutting process has been investigated as typical example to detect an abnormal vibration. Then the difference between the two stages of normal condition and chattering has been obtained based on the tendency of correlation exponents. Moreover, in order to reduce the noise, only principal components are used for re-embedding space and the modified version of Grassberger–Procaccia algorithm is applied to the re-embedding space. Then the correlation exponents estimated with the modified version of the Grassberger–Procaccia algorithm show more obvious distinction between normal and abnormal condition than those of original Grassberger–Procaccia algorithm.     

CMPO-TRUEX Process and its Application in the Separation of Actinides from High-Level Liquid Wastes

Abstract

Basic studies have been carried out on the high active PUREX raffinate to determine the distribution characteristics of actinides in different extraction systems. The data have been utilised in conducting a series of counter-current extraction experiments, which have led to the establishment of a viable flow-sheet based on a unique PNC salt-free process, that has great potential in minimizing secondary radioactive waste generation. The process was successfully applied to the present purex system, and a decontamination factor DFαof > 10³ has been achieved resulting in the formation of a much less toxic HLLW.

NMR studies carried out on the Ln Complex extracts have yielded valuable data on their thernio chemical and activation parameters. Consideration on the mechanism of degradation/regeneration/decomposition of TRUEX Solvents are also included.     

Optimal design of FIR linear phase digital filters via convex quadratic programming method

Many methods exist for designing FIR linear phase digital filters by using various optimization techniques. An optimization design method via the convex quadratic programming method is investigated in this paper. The aim of this method is to design digital filters with certain desired frequency responses that keep the passband ripple to a minimum while maintaining a balance between opposite characteristics of frequency responses, i.e. the narrow transition band and the great stopband attenuation. In order to verify the effectiveness of this method, low-pass filters are designed and comparison studies with other typical optimization methods are given.     

Social choice function with subordinate relations as one variable

The paper proposes a social choice function R = g(R₁ R₂, ?,R_n, U) with a binary relation U called a subordinate relation on the group decision-makers in addition to individual preference relations R_i(i = 1, 2, ?, n). Then the individual influence to the group decision-making is connected with a relation U so that the more the members are subordinate to a member, the more its preference is reflected to the social preference. Two functions are defined as examples of such functions with subordinate relations. Four conditions, a theorem and real-world type examples to group decision-making are presented