Earticle

The use of ICT (Information and Communication Technology) to activate distance education courses has made it possible to create new ways of training, certainly more efficiently and potentially more effectively. Internet, and in particular the World Wide Web, is becoming a learning space which is used increasingly in several educational contexts from secondary schools to post graduate courses. Learners can choose to take training modules and, in some cases, entire programs through the Net; the on line environment may be the only possibility to acquire knowledge on some topics for learners who do not have the opportunity to attend traditional classes; besides the communicative power of Internet tools can allow the activation of new ways of teaching/learning. As the number of on line learners is increasing, it is crucial for training centers and institutions to create effective on-line learning environments according to the specific needs of each learner. In fact, a lot of aspects have to be taken into account to project and activate a good distance course: effective presentation of contents, consideration of individual differences of users, adoption of several models according to educational objectives, and so on. In this paper we propose a pedagogical learning environment which and which makes students more interactive in learning process. Our system lets students collaborate among them in order to construct their knowledge as much as possible and to find solutions of many problems that occur during learning.

Network Security for data transmission is the most vital issue in modern communication system. In this paper, we have discussed a new steganographic technique. The effectiveness of the proposed method is described through which idea of enhanced security of data can be achieved. To hide data in a binary image, no key is needed here rather this algorithm is based on the number of occurrence of 0s and 1s in data that has to hide and number of occurrence of 0s and 1s in the last bit of each pixel of binary image file. The proposed algorithm assures the security and the data hiding effect is quite invisible.

Measurement and data acquisition get the most accurate indicator, in mobile communication network. Channel occupancy for each cell shows the proportion of current traffic. In addition, call duration is another important target, which more precise estimate the users’usage situation in heterogeneous networks. A Flexible Bandwidth Allocation Scheme (FBS) using specified duration based data acquisition improves the quality of services (QoS) in heterogeneous networks. The FBS reduces the weight call loss probability (CLP) and improves performance in resource allocation and wireless channel utilization. Simulation results demonstrate the effectiveness of the scheme.

In this paper, we investigate a new solution for combined amplitude and phase modulation by employing elliptical signals. Signal characteristics of the proposed schemes are analyzed and then detection methods are investigated. The derived closed-form BER approximations, i.e. theoretical analysis results, are shown to be in agreement with simulation results. Furthermore, both results show that proposed schemes, compared conventional modulation schemes, can achieve better noise performance while suffering lower spectral efficiency, and can better realize trade-offs between error probability and spectral efficiency by dynamically varying eccentricity.

Bluetooth is a wireless communication technology that provides short-range, small-size, low-cost, and low-power connectivity among mobile devices. The MAC protocol for Bluetooth is based on a Time Division Duplex (TDD) scheme, where the master determines channel access to all other slaves in the piconet. Hence, the polling scheme used by the master has a significant effect on the Bluetooth system performance. Accordingly, this paper proposes an enhanced Limited Round Robin with a priority policy for Bluetooth. In simulations, the proposed scheduling algorithm demonstrates a better overall performance in a Bluetooth network.

This article introduces briefly the theory for estimation of fingerprint image quality. This is followed by the description of experiments with fingerprint image quality, concretely image contrast, mean value and number of papillary lines in fingerprint using the scanners Suprema.

Coronary artery bypass surgery is currently a widely used technique for relief of the effects of coronary atherosclerosis. This disease of coronary arteries is a major cause of death. It has been found that, in the developed countries 25% ~30% people become victims of the coronary heart disease, which is described by WHO as the modern epidemic.