IEEE 802.11p based Dedicated Short-Range Communication (DSRC) is considered a potential wireless technology to enable transportation safety and traffic efficiency. A major challenge in the development of IEEE 802.11p technology is ensuring communication reliability in highly dynamic Vehicle-to-Vehicle (V2V) environments. The design of IEEE 802.11p does not have a sufficient number of training symbols in the time domain and pilot carriers in the frequency domain to enable accurate estimation of rapidly varying V2V channels. The channel estimation of IEEE 802.11p is preamble based, which cannot guarantee a suitable equalization in urban and highway scenarios, especially for longer length data packets. This limitation has been investigated by some research works, which suggest that one major challenge is determining an accurate means of updating channel estimate over the course of packet length while adhering to the standard. The motivation behind this article is to overcome this challenge. We have proposed an improved Constructed Data Pilot (iCDP) scheme which adheres to the standard and constructs data pilots by considering the correlation characteristics between adjacent data symbols in time domain and adjacent subcarriers in frequency domain. It is in contrast to previous schemes which considered the correlation in the time domain. The results have shown that the proposed scheme performs better than previous schemes in terms of bit error rate (BER) and root-mean-square error (RMSE).

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Security testing is the process of detecting the exploited defects which conduct attacks. Since SQL Injection vulnerabilities are one of the most common threats of a web-based application, testing still the most important technique in order to gain confidence that an articraft behaves as expected. This scenario occurs when untrusted inline simple inputs are accepted as a database input which can lead to some security breaches such as altering the intent of the original query and getting some privileges, leaking of private information, authentication bypassing…etc. Although the awareness of SQL Injection attacks, the risk is increasing and the consequences are very severe, still many people do not have very concrete ideas on how to prevent against them. It becomes not easy to check and test the application data flaws, but since the manually testing is hard and time-consuming security testing and fuzzing test remain the tools where almost all worldwide companies focus are concentrated rather than web application scanners. In practice Software's Vulnerabilities detections mean the obtaining of adequate test cases set that contain effective queries or attacks that reveal new data flaws and define the risk, identifying the unexpected behavior by performing test cases generation based on the mutation to mitigate that risk with new attack scenarios. In this paper we applied the idea of mutation-based test cases generation to get a new set of test cases to test against SQL Injections attacks. The results can be used for web-applications penetration testing, fuzz testing, SQL injection detection and prevention, it can also be used to compare between brute force tools, web-application scanners effectiveness, enlarge the space of test cases what can reduce the time costs of testing process and finally software's quality assurance.

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