Multiresolution-based bilinear recurrent neural network

A multiresolution-based bilinear recurrent neural network (MBLRNN) is proposed in this paper. The proposed MBLRNN is based on the BLRNN that has robust abilities in modeling and predicting time series. The learning process is further improved by using a multiresolution-based learning algorithm for training the BLRNN so as to make it more robust for the prediction of time series data. The proposed MBLRNN is applied to the problems of network traffic prediction and electric load forecasting. Experiments and results on both practical problems show that the proposed MBLRNN outperforms both the traditional multilayer perceptron type neural network (MLPNN) and the BLRNN in the prediction accuracy.

Reduction of acrylamide by taurine in aqueous and potato chip model systems

Acrylamide in foods is mainly produced by Maillard reaction. Taurine can participate in the reaction, which has led us to investigate the possibility of reducing acrylamide formation by use of taurine. In an aqueous system, the lower the pH of the solution the greater the inhibition of acrylamide formation within a pH range of 5.0–8.0 was found, and the inhibition of acrylamide formation by taurine was dose-dependent. In a fried potato chip model, prior to frying at 170 °C for 3 min, the potato slices soaked in 0.l% to 2% taurine solution for 30 min showed significant reductions of acrylamide formation; however, these reductions were not dose-dependent. Also, the soaking treatments for 15–60 min significantly reduced acrylamide formation, but the inhibitory effects were not time-dependent. Thus, taurine, when used in a narrow range of reasonably low levels, is a candidate to inhibit acrylamide formation during frying process.     

A study on the behaviors and stresses of O-ring under uniform squeeze rates and internal pressure by transparent type photoelastic experiment

The behaviors and stresses of an O-ring under uniform squeeze rates and internal pressure change with real time. Therefore, the behaviors and stresses of O-rings under uniform squeeze rates and internal pressures should be studied with real time. To achieve this, a loading device for a transparent type photoelastic experiment, through which various internal pressures and uniform squeeze rates are applied, was developed. The validity of the loading device in analyzing the behaviors and stresses of the O-ring under uniform squeeze rates and internal pressures with real time was verified. It was observed that the filling phenomenon of the O-ring into the space between the lower and front side occurred after forcing out continued for a duration of time. The study also indicated that maximum shear stress would be more effective as a fracture parameter than the maximum normal stress fracture criterion for an O-ring made from rubber.     

A shortest path routing algorithm using Hopfield neural network with an improved energy function

A shortest path routing algorithm using the Hopfield neural network with a modified Lyapunov function is proposed. The modified version of the Lyapunov energy function for an optimal routing problem is proposed for determining routing order for a source and multiple destinations. The proposed energy function mainly prevents the solution path from having loops and partitions. Experiments are performed on 3000 networks of up to 50 nodes with randomly selected link costs. The performance of the proposed algorithm is compared with several conventional algorithms including Ali and Kamoun's, Park and Choi's, and Ahn and Ramakrishna's algorithms in terms of the route optimality and convergence rate. The results show that the proposed algorithm outperforms conventional methods in all cases of experiments. The proposed algorithm particularly shows significant improvements on the route optimality and convergence rate over conventional algorithms when the size of the network approaches 50 nodes.     

System modeling and robust control of an AMB spindle : part II a robust controller design and its implementation

This paper discusses an entire procedure for a robust controller design and its implementation of an AMB (active magnetic bearing) spindle, which is part II of the papers presenting details of system modeling and robust control of an AMB spindle. Since there are various uncertainties in an AMB system and reliability is the most important factor for applications, robust control naturally gains attentions in this field. However, tight evaluations of various uncertainties based on experimental data and appropriate performance weightings for an AMB spindle are still ongoing research topics. In addition, there are few publications on experimental justification of a designed robust controller. In this paper, uncertainties for the AMB spindle are classified and described based on the measurement and identification results of part I, and an appropriate performance weighting scheme for the AMB spindle is developed. Then, a robust control is designed through the mixedμ synthesis based on the validated accurate nominal model of part I, and the robust controller is reduced considering its closed loop performance. The reduced robust controller is implemented and confirmed with measurements of closed-loop responses. The AMB spindle is operated up to 57,600 rpm and performance of the designed controller is compared with a benchmark PID controller through experiments. Experiments show that the robust controller offers higher stiffness and more efficient control of rigid modes than the benchmark PID controller.     

System modeling and robust control of an AMB spindle: part I modeling and validation for robust control

This paper discusses details of modeling and robust control of an AMB (active magnetic bearing) spindle, and part I presents a modeling and validation process of the AMB spindle. There are many components in AMB spindle : electromagnetic actuator, sensor, rotor, power amplifier and digital controller. If each component is carefully modeled and evaluated, the components have tight structured uncertainty bounds and achievable performance of the system increases. However, since some unknown dynamics may exist and the augmented plant could show some discrepancy with the real plant, the validation of the augmented plant is needed through measuring overall frequency responses of the actual plant. In addition, it is necessary to combine several components and identify them with a reduced order model. First, all components of the AMB spindle are carefully modeled and identified based on experimental data, which also render valuable information in quantifying structured uncertainties. Since sensors, power amplifiers and discretization dynamics can be considered as time delay components, such dynamics are combined and identified with a reduced order. Then, frequency responses of the open-loop plant are measured through closed-loop experiments to validate the augmented plant. The whole modeling process gives an accurate nominal model of a low order for the robust control design.     

A study on the initial crack curving angle of isotropic/orthotropic bimaterial

In this paper, when the initial propagation angle of a branched crack is calculated from the maximum tangential stress criterion (MTSC) and the minimum strain energy density criterion (MSEDC), it is essential that you use stress components in which higher order terms are considered and stress components at the position in a distance 0.005 mm from the crack tip ( =γ . When an interfacial crack propagates along the interface at a constant velocity, the initial propagation angles of the branched crack are similar to the mode mixities (phase angle) and the theoretical values obtained from MTSC and MSEDC. The initial propagation angle of the branched crack depends considerably on the stress intensity factor K{IN2}.     

Poly(t-butyl-3α-(5-norbornene-2-carbonyloxy)-7α,12α-dihydroxy-5β-cholan-24-oate-co-maleic anhydride) for a 193-nm photoresist

A copolymer of t-butyl-3α-(5-norbornene-2-carbonyloxy)-7α,12α-dihydroxy-5β-cholan-24-oate and maleic anhydride was synthesized as a matrix polymer for ArF excimer laser lithography. The polymer has an excellent transmittance at 193 nm and possesses good thermal stability up to 255°C. The resist formulated with the polymer showed better dry-etching resistance than the conventional KrF excimer laser resist for chlorine and oxygen mixed gas. A 0.15 μm line and space patterns were obtained at a dose of 18 mJ cm⁻² using an ArF excimer laser stepper.     

Design and fabrication of a scanning electron microscope using a finite element analysis for electron optical system

In this paper, we describe the design and fabrication of a thermionic scanning electron microscope (SEM) and examine its characteristics analytically. In the design process, the dimensions and capacity of the SEM components, such as the electron column, lenses, and apertures, were determined using finite element analysis. All components were integrated systematically during fabrication in order to achieve the maximum performance by adjusting the lens parameters, high voltage source, and image calibration methods. As a result, a thermionic SEM image with high resolution was achieved. We discuss the primary considerations required to achieve a high-performance image.     

Calculation of mixed lubrication at piston ring and cylinder liner interface

This paper reports on the theoretical analysis of mixed lubrication for the piston ring. The analytical model is presented by using the average flow and asperity contact model. The cyclic variations of the nominal minimum oil film thickness are obtained by numerical iterative method. The total friction is calculated by using the hydrodynamic and asperity contact theory. The effects of the roughness height, pattern, and engine speed on the nominal minimum film thickness, friction force, and frictional power losses are investigated. As the roughness height increases, the nominal oil film thickness and total friction force increase. Also, the effect of the surface roughness on the boundary friction is dominant at low engine speed and high asperity height. The longitudinal roughness pattern shows lower mean oil film pressure and thinner oil film thickness compared to the case of the isotropic and transverse roughness patterns.