Orthogonal Frequency Division Multiplexing (OFDM) is one of recent years multicarrier modulation used in order to combat the Inter Symbol Interference (ISI) introduced by frequency selective mobile radio channel. The circular extension of the data symbol, commonly referred to as cyclic prefix is one of the key elements in an OFDM transmission scheme. This paper study The influence of the cyclic prefix duration on the BER performance of an OFDM-VCPL (Orthogonal frequency division multiplexing - Variable Cyclic Prefix Length) system and the conventional OFDM system with frame 64-QAM modulation is evaluated by means of computer simulation in a multipath fading channel. The adaptation of CP is done with respect to the delay spread estimation

With the increasing rates of cancer worldwide, a great deal of scientific discourse is devoted to arguments and statements about cancer and its causes. Scientists from different fields try to seize any available chance to warn people of the risk of consuming and exposing to carcinogens that have, unfortunately, become essential parts of modern life. The present paper attempts to investigate the proximization strategy through which scientists construct carcinogen risk to enhance people’s preventive actions against these carcinogens. The paper targets the construction which depends on producing the conflict between the values of the people themselves and the contrasting values assigned to carcinogens. To achieve this aim, Cap’s (2

 Data Driven Requirement Engineering (DDRE) represents a vision for a shift from the static traditional methods of doing requirements engineering to dynamic data-driven user-centered methods. Data available and the increasingly complex requirements of system software whose functions can adapt to changing needs to gain the trust of its users, an approach is needed in a continuous software engineering process. This need drives the emergence of new challenges in the discipline of requirements engineering to meet the required changes. The problem in this study was the method in data discrepancies which resulted in the needs elicitation process being hampered and in the end software development found discrepancies and could not meet the need

The rapid changes in the field of transferring and exchanging information via cloud platforms have revolutionized the field of modern visual media, as cloud computing technology has greatly influenced the media institutions, providing effort, money and high-quality materials. The research included five chapters, the first came under the methodological framework for the research and the second Theoretical framework, the first two included the concept of cloud computing and the second platforms for cloud computing in the visual media and the third chapter Research procedures and the fourth chapter The sample analysis and the fifth chapter The research results were the most prominent
1. The cloud service made the benefit beyond the typic

This paper presents the Extended State Observer (ESO) based repetitive control (RC) for piezoelectric actuator (PEA) based nano-positioning systems. The system stability is proved using Linear Matrix Inequalities (LMIs), which guarantees the asymptotic stability of the system. The ESObased RC used in this paper has the ability to eliminate periodic disturbances, aperiodic disturbances and model uncertainties. Moreover, ESO can be tuned using only two parameters and the model free approach of ESO-based RC, makes it an ideal solution to overcome the challenges of nano-positioning system control. Different types of periodic and aperiodic disturbances are used in simulation to demonstrate the effectiveness of the algorithm. The comparison studi