Earticle

Nanoscience and nanotechnology involve the ability to see and to control individual atoms and molecules. A quantum-dot cellular automata(QCA) is one of the attractive alternative technology among nanotechnology solutions. Demultiplexer is used in communication systems to convert the serial data to the parallel data. A demultiplexer receives the output signals from the multiplexer. For that reason, it is important components for making integrated circuit. This work target is designing a high optimized demultiplexer in QCA framework. We proposed designs of 1:2 and 1:4 demultiplexer and the simulation results reveal that our proposed designs have significant improvements, such as low complexity and power consumption aspects.

For a real-time system, the system correctness depends not only on the correctness of the logical result of the computation but also on the result delivery time. Real-time Operating System (RTOS) is widely accepted in designing real-time systems. The real-time performance is achieved by using real-time mechanisms through data communication and synchronization of inter-task communication (ITC) between tasks. Therefore, benchmarking the response time of real-time mechanisms is a good measure to predict the performance of real-time systems. This paper aims to analyze the response characteristics of real-time mechanisms in kernel and user space for real-time embedded Linux: RTAI and Xenomai. The performance evaluations of real-time mechanisms depending on the changes of task periods and load are also conducted in kernel and user space. Test metrics are jitter of periodic tasks and response time of real-time mechanisms including semaphore, real-time FIFO, Mailbox and Message queue. The results are promising to estimate deterministic real-time task execution in implementing real-time systems using RTAI or Xenomai.

In this paper we propose a new bit plane-based watermarking approach. In the proposed technique, an image is embedded in the least significant bit (LSB) plane of the original image. The selection of bit planes is a crucial issue because the performance and file size is determined by the selected bit plane. We used ten LC dataset for the experiments. From the simulation results, it is obvious that the presented method is reliable for watermarking.

A tri-axial HTS power cable has been proposed and developed to reduce the number of HTS wires because it has copper shield instead of HTS shield. However, it has a drawback which is an inherent imbalance problem due to an asymmetry configuration in the cable. The authors designed a 22.9 kV/50 MVA class tri-axial HTS cable. The inherent imbalance problem of the three-phase currents in the tri-axial HTS power cable has been minimized through the adjustment of pitches and radii of each layer. An FEM analysis program and a power system analysis program were used to analyze the characteristics of the designed tri-axial HTS power cable. The AC loss and magnetic characteristics of the designed cable were analyzed according to magnitude of operating currents. The design results of the tri-axial HTS power cable are discussed in detail.

We propose a moving target tracking algorithm using the measurement signals of time difference of arrival (TDOA) and the frequency difference of arrival (FDOA) in this paper. The geolocation system using TDOA measurement does not have enough accuracy to estimate the position of target. We use both TDOA and FDOA measurement signals to estimate the target location and target’s velocity at discrete times. The Kalman filter performs remarkably in calculation and location estimation. However, the estimation error can be large when the priori noise covariances are assumed with improper values. Therefore, we offer an adaptive extended Kalman filter (AEKF) to update the noise covariance at every measurement and estimation process to find proper noise covariance at each steps. The simulation results show our proposed algorithm reduces the position error effectively and improves the accuracy of target tracking greatly.

This paper presents a decoder with enable input. This decoder is developed using quantum-dot cellular automata (QCA). QCA opens a completely radical way of microelectronics development and a potential replacement of CMOS based electronics. It ensures highly compact circuits, faster processing speeds, low power consumption. The use of clock in QCA provides power gain which is an important feature and this feature is not available in CMOS electronics. The proposed decoding architecture is designed using 5-input majority gate to keep a regularity so easily extendable for 3:8 or 4:16 decoders and also easy to connect with other circuits.

The traditional approach to limiting the maximum output power of a FSAE car’s engine is to install a single circular restrictor at the engine. However, restrictor installation would adversely lower the air flow speed and fuel burning rate, which further result in the declining of the pressure in the intake pipe. In this paper, we first analyze the influence of intake restrictor on engine power, intake pipe’s pressure, inflatable efficiency and fuel consumption in the case of a typical four-stroke engine of FSAE cars. One-dimensional engine cycles are simulated by using the AVL BOOST. Intake quantity correction is then designed based on the characteristics of EFI system and the analysis results. The control unit is further designed by both means of hardware circuit and software design. According to pulse width of driving signal for injecting fuel, the performance of FSAE car’s engine is improved by intake quantity correction of the control unit. Other direct improvement includes lowered fuel consumption hence more economical efficiency.

This paper introduces the design and analysis of two types of novel inherently compliant actuators. The two actuation systems are characterized by the property that the output apparent stiffness can be varied independently from the position. The two proposed actuators can regulate the stiffness through the adjustable moment arm mechanism with minimum energy consumption. In the first VSA, this behavior is realized by implementing a lever arm mechanism with variable pivot point position. Compared with the existing VSA that based on the lever arm principle, the way of the spring compressed is more convenient to be implemented by using the tendon and pulley mechanism. Furthermore, the kinematic structure for spring compression is more beneficial for dealing with the unexpected dynamic collision situation. The internal elastic elements of the VSA use the fitted quadratic spring, which improve the characteristics of actuating torque and output stiffness. The stiffness regulation of the second VSA is realized by implementing the connecting rod and slider mechanism. This is a equivalent model of the lever arm mechanism with a variable length moment arm. The stiffness of the VSA is only related to the effective working radius for linear spring configuration, but not to the applied external torques or the deflection angle. This feature makes the stiffness control of the VSA more convenient. The working principles of the two actuators are elaborated and the characteristics of torque and stiffness of the VSA are presented. The mechanical solutions of the two actuators are described.

This paper presents a frequency monitoring system for Korean wide-area power protection based on virtual FDR. The virtual FDR is introduced to enhance the simulation capability of frequency monitoring systems and consists of three parts: modeling, estimation, and simulation. Once a power grid model is obtained in the virtual FDR based on EMTP-RV, the frequency is estimated by DFT filtering and gain compensation based on real and imaginary filtering. Various disturbances and conditions are simulated using the data from the power grid model. The proposed FDR allows the monitoring system to display simulated disturbances and data, including voltages, currents, and frequencies. Various simulation results were given to show of the effectiveness of the proposed frequency monitoring system based on the virtual FDR.