Earticle

The national capacity around the world has focused to the development of renewable energy in order to respond to energy, environment, security and economic. Among them, the unit price of wind turbine was reduced by technical maturity. So, the comparative advantage against other renewable energies can be achieved because of proximity to the unit price of the existing fossil fuel. In other words, the wind turbine is the only alternative energy that can ensure that a competitive price is equal to the fossil fuels in the short term. The onshore wind turbine has difficulty to secure additional location by the depletion of good location and the increase in civil complaint. The korea also has factors of problem such as limitation of locational condition and noise. Therefore, it is essential to advance to the sea. However, the mechanical and electrical allowance that components of wind turbine must withstand was increase in a corresponding degree. Therefore, the possibility of failure was increased, and then the secondary damage by limited access caused additional costs by locating offshore. In this paper, in order to diagnose fault in advance and ensure the reliability of large wind turbine located in the sea, we took advantage of the condition monitoring system (CMS). In other words, we propose effective monitoring and control system by integrating the CMS and SCADA systems based on LabVIEW. First, the remote monitoring system based on PC using the ethernet gateway of wireless sensor network (WSN) should be constructed in order to overcome the environment of positional constraints. And then we collect measured signal data from distributed nodes of the installed WSN within wind turbine farms and extract feature information of the classified fault and normal signals pattern through Wavelet Analysis. The extracted feature information is used as the input of neural network learning. When the error signals have arisen in the wind turbine farms, it is possible that alarm is happen, and condition is controlled through the automatic fault diagnosis. In addition, simple faults as well as complex faults that occur over a long time can be diagnosed early.

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 new hybrid algorithm is proposed in this paper. An independent task scheduling algorithm is designed based on the hybrid algorithm. The hybrid algorithm adopt list scheduling method to code harmony solution and convert harmony vector to priority-based independent task scheduling model, and perform variable neighborhood search on harmony solutions to improve Harmony Search efficiency and solution quality. The simulation results demonstrate that the proposed algorithm can improve the global search abilities and convergence speed and can escape local minimizer to look for better solutions.

This paper presents analysis on the performance and stability of an integral-derivative feedback system for active tip pointing control of a very flexible and slender cantilever beam. Since a piezoceramic PZT actuator at the fixed-end and a non-contacting displacement sensor at free-end of the beam are used for the control, the non-collocation of the sensor and the actuator makes that the plant is a non-minimum phase system. So this tip pointing control for a lightly damped beam requires a careful consideration on robust stability. Although the integral-derivative controller is simple to implement and its performance is modest, it can provide very robust stability. This is really important in some critical control systems. After computer simulation, it is observed that the integral-derivative controller can reduce the settling time to 50 % with robust stability and control gains. The stability and performance of the control systems in terms of the time domain and the frequency domain are discussed in detail. Thus the integral-derivative controller could be very effective to a tip pointing control of a flexible cantilever beam.

Hierarchical Mobile IPv6 introduces a new node called the Mobile Anchor Point (MAP) to improve the handover speed performance of Mobile IPv6 by reducing the amount of signaling in the ongoing connection between the mobile node, its correspondent nodes, and its home agent. With MAP as an additional node, it’s signaling, both received and sent is subject to several security vulnerabilities that needs addressed. Authentication and authorization of Binding Updates (BUs) to the MAP is essential during the registration process. This paper deals with securing the hierarchical mobile IPv6 handover scheme by adding a cryptography procedure for authenticating the binding updates sent by mobile nodes during the mobile anchor point registration process.

In this paper, a DOA estimation method using subarray and spatial smooth is proposed. The DOA is then estimated based on the computation of the phase shift between the reference signal and its phase shifted signal. To significantly improve the robustness of DOA estimation and of beamforming and to estimate azimuth angle in multipath mobile channel environment, we developed techniques for applying spatial smooth subarray method to arrays of linear geometry. We developed method for applying spatial smooth subarray to arrays of arbitrary geometry. We study the cause of ambiguities in a multiple signal environment and find the necessary and sufficient conditions for an array manifold to be ambiguity free. We show that can be the application of our method MUSIC and adaptive beamforming method. The estimation results are verified by simulations.

The lime time of LED sensor luminaire decreases due to many factors, being the heat is one of them. We develop a controller to expand the lifetime of LED sensor luminaire. By controlling the current through the LED, the temperature of PN junction of LED maintains the proper level to prevent the overheating of LED, then the lifetime can be expanded. This study measures the illumination of Maximum life span refers to a measure of the maximum amount of time one or more members of a population has been observed to survive between birth and death. This study shows the method to measure the illumination of LED, controls the amount of current flows in order to maintain the level of illumination of LED output, extend the lifetime of LED, and guarantees the minimum illumination of LEDs.

Packet transmitting among the clusterheads which is the head of a cluster in wireless ad hoc networks are carried out through gateway nodes. Nodes in a cluster communicate through the head node to other nodes. Existence of multiple gateways between the clusters means multiple path existence. Multiple transmissions of packet though redundancy paths may not desire for efficient resource usage. Therefore, the communications between clusterheads by selecting the most stable and effective gateway are a fascinate solution. In this paper, we propose gateway selection methods to support a stable path connection. The comparisons by characteristics of proposed methods are analyzed.

In the packet based systems for supporting burst data traffic networks, the fast synchronization is required in the short period of time upon receiving the data frame at the receiver. This important operation is generally carried out at the header part of the packet which is usually called the preamble. While detecting the existence of the valid signal frame through the carrier sensing it is also important to adjust the signal level at the input of the baseband blocks. This is generally called automatic gain control and it is essential to minimize the processing time for the gain decision for incoming received signals. In this paper, target level of the AGC is determined based on the bit-error-rate (BER) performance and SQNR for the varying power of the AGC input signal. The other parameters are optimized by utilizing statistics of the incoming signal including the degree of saturation as well as the incoming signal power. The proposed optimization method provides the improved convergence speed which in turn results in the reduced processing time.