روايات سيرت كى تحقيق كا حديثى معيار

Seerah is a separate Islamic science from Hadith as their primary sources are different. Although there are some extents where there is over laying between them, but traditionally Seerah has different principles as compared to Hadith. The Scholars of Hadith were very strict in applying their rules whereas the scholars of Seerah were more flexible. The reason is, when academics were dealing with Ahadiths and deducingdivine rulings, they wanted to make sure they were founding the rulings on Ahadiths that were authentic and sound. So that is why they applied very stringent rules to accept Ahadith. However, when it came to Seerah, they were more flexible in their rules, because they study this as history of The Prophet PBUH which does not touch the Sharia rulings. So, we find that writers of Seerah would accept narrations, they would not usually accept if they were dealing with Ahadith. This practice with Seerah narrations was followed by our early scholars. But recently, there is a new movement among some of our researchers that they wanted to apply the rules of Ahadith on Seerah. We do not agree this approach and in this article, we have had a humble effort to compile a set of rules for acceptance of Seerah narrations.

Performance Analysis of Spectrum Sensing Methodologies for Cognitive Radios

The Radio Spectrum is used to transmit electromagnetic waves of different frequencies. With the passage of time people are getting aware of new technologies and as a result demand for different services has been increased. This results in the shortage of available spectrum. Spectrum utilization has now become a challenging task due to increase in wireless communications. Major licensed bands, such as those allocated for television broadcasting is not been fully utilized which results in spectrum wastage. This led to the idea of cognitive radio, first presented officially by Mitola and Maguire in 1999. Cognitive radio is a software-defined radio system, or SDR, a radio whose functionality is completely defined in software. Changes in SDR can be made by just changing the software. Mitola and Maguire proposed that the unused spectrum can be utilized by Secondary users (Unlicensed users) without creating harmful interference to Primary users (Licensed users). Secondary user can use the spectrum when primary user is inactive and should vacate the channel as soon as the primary user becomes active. An Efficient Signal Detection algorithm can perform this task. Detection of primary user signal is an elementary problem in cognitive radio. Energy detection, Match-filtering and Cyclostationary methods are widely used for spectrum sensing. This thesis will explore spectrum sensing methods and will analyze the performance of different techniques including methods based on the eigenvalue of the covariance matrix of received signals used as the test statistic. Different methods working with and without noise power will be simulated to demonstrate the performance of spectrum sensing techniques.