Current-controllable FDNRs using linear transcapacitance amplifiers

A systematic synthesis process is described for the simulation of current-controllable FDNRs using linear transcapacitance amplifiers. The process is used to obtain three circuits; two are believed to be novel. The values of the FDNRs are controllable by adjusting the bias currents of the transcapacitance amplifiers. In order to implement the obtained FDNRs, a new transcapacitance amplifier is designed. Operation principles of designed circuits are presented and experimental results are used to verify theoretical predictions. The results show close agreement between predicted behaviour and experimental performance.     

In vivo functional effects of Weissella confusa VP30 exopolysaccharides on loperamide-induced constipation in rats

Food Science and Biotechnology - In this work, the in vivo functionalities of milk fermented with Weissella confusa VP30 (VP30-EPS) and purified exopolysaccharide (pEPS) from the milk fermented...     

Triangular/square-wave generator with independently controllable frequency and amplitude

A triangular/square-wave generator with current-controllable frequency and amplitude is presented. The generator utilizes operational transconductance amplifiers as switching elements. A prototype circuit built with commercially available components exhibits less than 2% nonlinearity in its current-to-frequency transfer characteristic from 1 to 10 kHz and -150 ppm//spl deg/C temperature coefficient of frequency over 15/spl deg/C to 35/spl deg/C. The circuit also displays wide sweep capability and good linearity of current to amplitude. The application of the circuit to a current-controllable saw-tooth waveform generator is also presented.     

Pulsewidth Modulation Circuits Using CMOS OTAs

This paper presents three pulsewidth modulation modulators using CMOS operational transconductance amplifiers. They consist of a ramp integrator and current-tunable Schmitt triggers. Prototype circuits built using discrete components exhibited that their duty cycles are linearly controllable. Because of their simple structure, the proposed modulators can be easily fabricated in a monolithic integrated circuit.     

Null space damping method for local joint torque optimization of redundant manipulators

In this article, a null space damping method is proposed that solves the stability problem commonly encountered in existing local joint torque optimization techniques applied to redundant manipulators. The damped joint motion is stable and globally outperforms undamped techniques in the sense of torque minimization capability. In addition, simulation results show that the resulting damped joint motion becomes conservative after an initial transient stage for cyclic end-effector trajectories, while undamped pseudoinverse solutions are reported to never lead to conservative motion. Three undamped and damped joint torque optimization algorithms are considered and discussed with comparison to the previous literature. The effectiveness of the proposed null space damping method is demonstrated by the results of two computer simulations. In addition, the minimization of electrical power consumption is addressed with respect to the results of this article.     

A self-driven active clamp forward converter using the auxiliary winding of the power transformer

This study proposes a new self-driven active clamp forward converter eliminating the extra drive circuit for the active clamp switch. The converter used the auxiliary winding of the power transformer to drive the active clamp switch and a simple RC circuit to get the dead time between the two switches. The operation principle was presented and experimental results were used to verify theoretical predictions. A 100-W (5 V/20 A) prototype converter that only exhibited 1.5-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input of 50 V. Finally, the measured efficiency of the converter was presented and the maximum efficiency of 91% was obtained.     

A model-based fault diagnosis scheme for wheeled mobile robots

In this paper, a fault diagnosis scheme for wheeled mobile robots is presented. In the fault detection module, a nonlinear observer is designed based on the mobile robot dynamic model. A fault is detected when at least one of the residuals exceeds its corresponding threshold. After the fault is detected, the fault isolation module is activated to isolate three types of fault: right wheel fault, left wheel fault, and other changing dynamic parameter faults. Three simulation examples are performed to show the effect of each fault to the tracking performance of mobile robot in a real situation. The simulation results demonstrate the effectiveness of our proposed approach for fault detection and isolation in wheeled mobile robots.     

P2P-based u-health cluster service model for silver generation in PBR platform

As the number of the silver generation increases, u-health service has evolved into more preventive services accessible in any type of service environment based on service platforms from the previous treatment and management-oriented services for specific diseases. U-health service used to solely provide remote diagnosis and counseling or biometrics monitoring, facing limitations in preventing or managing potential chronic disease cases. In this recognition, the research seeks to propose a P2P-based u-health cluster service model for silver generation in PBR(Personal Bio Record) platform. The proposed u-health service herein utilizes PCs and smart phones to provide health, dietary and exercise information regardless of time and space. Based on the PBR platform, the system effectively connects the EMR system and users’ service systems in order to understand service targets’ lifestyle patterns and offer further customized services. This u-health cluster service model is expected to realize useful services to user in a multi-platform environment and contribute to enhanced health status of senior patients with chronic disease.     

A robust fault diagnosis and accommodation scheme for robot manipulators

This paper investigates an algorithm for robust fault diagnosis (FD) in uncertain robotic systems by using a neural sliding mode (NSM) based observer strategy. A step by step design procedure will be discussed to determine the accuracy of fault estimation. First, an uncertainty observer is designed to estimate the uncertainties based on a first neural network (NN1). Then, based on the estimated uncertainties, a fault diagnosis scheme will be designed by using a NSM observer which consists of both a second neural network (NN2) and a second order sliding mode (SOSM), connected serially. This type of observer scheme can reduce the chattering of sliding mode (SM) and guarantee finite time convergence of the neural network (NN). The obtained fault estimations are used for fault isolation as well as fault accommodation to self-correct the failure systems. The computer simulation results for a PUMA560 robot are shown to verify the effectiveness of the proposed strategy.     

Dimming Control Characteristics of Electrodeless Fluorescent Lamps

The study described in this paper was undertaken to identify the dimming control characteristics of the electrodeless fluorescent lamp. First, to accomplish this, a model of the electrodeless fluorescent lamp was made. Two kinds of dimming control methods, the variable switching frequency control method and the variable dc-link voltage control method, were then applied to the resulting model of the lamp, after which the results of the application of the two methods on the lamp model were compared. The hypotheses that were initially formulated were confirmed by the results of the experiment that was conducted on the 100-W ENDURA-type electrodeless fluorescent lamp. The results show that the lamp's dimming control of the switching frequency control is nonlinear and that of the variable dc-link voltage is linear over a wide range, and the theoretical value obtained by the proposed model well matches that of the experimental value.