University of Wah

About: University of Wah is a education organization based out in Rawalpindi, Pakistan. It is known for research contribution in the topics: Per capita income & Rhizobacteria. The organization has 258 authors who have published 466 publications receiving 4719 citations.

Generalized mapping for multiset rewriting systems

Abstract: This work furnishes mathematical apparatus for theoretical foundations of multisets as used in Algebraic, Modal and Temporal Logics. It establishes a sufficiently generalized concept of mappings on multisets, thus resolving a long-standing obstacle in the structural study of multiset processing. It has been shown that the mapping defined herein is applicable to a vast array of already defined rewriting problems within the domain of Theoretical Computer Science. Specifically, this paper unifies and generalizes the works of Parikh in Dassow (2000), Hickman (1980), Khomenko (2003) and Nazmul et al. (2013).

A Comprehensive Investigation of Formal System Verification Tools and Approaches.

Abstract: System testing is a complex process that takes major portion of total project cost. The verification of the system is usually performed once major implementation is carried out in the desired programming language. It is more costly and time consuming to fix the errors reported after implementation. In this context, formal verification is used to mathematically test the system in early development stages. Although there are several formalisms and tools available to perform formal verification, it is always difficult to choose the right formalism and tool for the system verification. Therefore, in this article, a comprehensive investigation of modern formal techniques and tools is performed. Particularly, 30 research studies published since 2009–2017 are selected where formal approaches and tools have been utilized for system verification (hardware as well as software systems). This leads to identify 3 formal system verification approaches, 6 formalisms and 12 formal verification tools. Finally, a detailed comparison of leading formal verification tools is performed.

DDT-based Chaotic Interleaver Aided Cooperative OFDM System

Abstract: Typically, interleaver is used to recover information signal from outage where errors in burst form is transformed into single errors. The best interleaver should have the optimal properties of spread and dispersion. Therefore, this paper reports a method to design highly dispersive and systematic interleaver. The interleaver is designed using an incremental approach, which uses a Chaotic Logistic Map (CLM) to generate interleaver positions and utilizes the counter-based difference distribution table (DDT) that has been used in cryptanalysis, in order to achieve highly random and disperse interleaver positions by avoiding bad positions that produce repetitive pairs in the output. The proposed interleaver is implemented in single input single out (SISO) and cooperative Orthogonal frequency division multiplexing (OFDM) system. The performance of the proposed interleaver is evaluated in terms of spread, dispersion, bit error rate (BER) as a function of the burst error length and BER versus channel signal-to-noise-ratio (SNR). The performance of the proposed interleaver is compared with chaotic interleaver, block interleaver and with Matlab® random interlaever. The results show that the proposed interleaver outperforms all the interleavers considered in the simulations and there is 1 dB to 3.5 dB improvement in different scenarios of length of burst errors in terms of BER for proposed SISO OFDM systems. More specifically, the employment of the proposed interleaver in the cooperative OFDM system gives improvement of about 2.75 dB to 3.5 dB at BER = 10−2, as compared to the non cooperative OFDM systems when having the burst error length of 5 bits, 10 bits and 15 bits.