Earticle

Co channel interference and adjacent channel interference of (WiBro) into Wireless LAN (WLAN) in TV White Spaces (TVWS) is evaluated through Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. As a result, in the case of co channel interference, the minimum distance between WiBro Mobile Station （MS） and WLAN User Equipment （UE） should be 210 m to allow the maximum transmitter power of WiBro UE of 25 dBm. The transmit power of WiBro BS have to be reduced to -4.96 dBm.

In this paper, we present an intelligent digital controller circuit which can be applied to automatic voltage regulation. The proposed solid state transformer with Pspice simulation model shows that our approach is very efficient and produces the desirable output. It is comparable to an ordinary magnetic coupled autotransformer.

This paper presents the concepts of ubiquitous computing technology to construct a ubiquitous learning environment that enables learning to take place anywhere at any time. This ubiquitous learning environment is described as an environment that supports students’ learning using digital media in geographically distributed environments. The u-learning model is a web-based e-learning system that could enable learners to acquire knowledge and skills through interaction between them and the ubiquitous learning environment. Students are allowed to be in an environment of their interest. The communication between devices and the embedded computers in the environment allows learner to learn while they are moving, hence, attaching them to their learningenvironment.

RDF data is widely used for exchanging data nowadays to enable semantic web era. This leads to the need for storing and retrieving these data efficiently and effectively. Recently, the structure index in graph-based perspective is considered as a promising approach to deal with issues of complex query graphs. However, even though there are many researches based on structure indexing, there can be a better architectural approach instead of addressing the issue as a part. In this research, we propose architecture for storing, query processing and retrieving RDF data in efficient manner using structure indexing. Our research utilizes research results from iStore and 2 relation-based approaches and we focus on improving query processing to reduce the time of loading data and I/O cost.

We introduce, in this paper, a novel approach of protection mechanism for data which are transmitted not only between the networked devices but also between the digital media devices. As the devices are getting more powerful and more storage capacity, they can process the encoded/encrypted data autonomously. However, all devices must know the secret key that used to encrypt data, and also use secure method to distribute that key. Moreover, there are no protection mechanisms supporting end-to-end copy protection which result in the fact that the data passed through various devices can be manipulated or captured. Therefore, we propose a RFID-based key distribution and protection mechanism to resolve these problems.