A novel BCS code in F-OFDM system: a promising candidate for 5G wireless communication systems

Due to the rapid growth in wireless communication systems, Long Term Evolution (LTE), mainly based on Orthogonal Frequency Division Multiplexing (OFDM), no longer meets wireless communication systems request and higher data rate requirements. Thus, to support a number of users, higher throughput, reliability, and lower latency, 5G is a candidate to meet these features. Furthermore, OFDM does not meet the demand of 5G because of its high Out Of Band Emission (OOBE) and Peak to Average Power Ratio (PAPR). Filtered-OFDM (f-OFDM) is considered an alternative waveform for OFDM and a candidate technique for 5G because of its lower OOBE and similar features of familiar OFDM. However, there is a trade-off among reducing OOBE, Bit Error Rate (BER) degradation, and rising PAPR. Therefore, a novel BCS code has been proposed in this thesis for the filtered-OFDM system to improve BER performance with maintaining its low OOBE. It is created using a new methodology that differs from conventional concatenated RS/BCH codes. Hence, an inner RS (7, 1) code has been proposed to achieve compatibility with an outer BCH (15, 5) code and appended by interleaver to create a novel BCS code with low complexity. The results showed that using a novel BCS code in LTE system reduces BER, significantly improved to be better than single and concatenated RS/BCH codes with low decoding complexity. On the other hand, using a novel BCS code in f-OFDM system achieved 0.8dB coding gain at 8×10-3 BER and 1dB coding gain at 2×10-3 BER versus conventional OFDM system in both BPSK and QPSK modulation schemes, respectively. Meanwhile, the proposed system reduced both OOBE and PAPR lower than the conventional OFDM system. In conclusion, due to its low OOBE, improving BER, and minimizing PAPR better than conventional OFDM system, the proposed system is presented as a high competitor candidate of 5G wireless communication systems

A study of positive energy condition in Bianchi V spacetimes via Noether symmetries

In this paper we use Noether symmetries of the geodesic Lagrangian in Bianchi V spacetimes to study various cosmological solutions of Einstein's field equations. Our first result is the identification of the subalgebras of Noether symmetries of the equations of motions in such spacetimes with dimension 4, 5, 6, 7, 9 or 10 of the maximal algebra of Lie point symmetries of dimension 13. Secondly we give physical interpretation of new cosmological solutions which satisfy positive energy condition and yield critical bounds on the expansion coefficient $\alpha$, in which the underlying non-flat spacetimes carry interesting physical properties. Specifically the energy density behaves in one of the following ways. (i) It is positive and constant for all time. (ii) It varies with time and attains a global maximum after some time and then asymptotically converges to zero. (iii) It increases for all time and attains a maximum value at the asymptotic limit $t\rightarrow \infty$. In particular a non-flat spacetime is obtained that mimics the expansion in a flat FRW universe dominated by vacuum energy such that the expansion factor has the same form in both. However, the energy density is dynamical in the former.Comment: Some typos are corrected. Some considerations into f(R) gravity is also carried out in the light of obtained results. Accepted for publication in EPJ

Fertility Transition in Pakistan: Evidence from Census

In the absence of an accurate and complete registration system, efforts were made to estimate the levels of vital statistics through sample surveys. The first such effort was made through the Population Growth Estimation (PGE) project conducted from January, 1962 to December 1965. Later on, various demographic surveys were conducted almost at regular intervals and the last effort in the series was Pakistan Reproductive Health and Family Planning Survey (PRHFPS) in the year 2000-01. Although all these efforts were made to ascertain levels and trends of various demographic events, yet the estimates particularly the ones on fertility remained controversial. The first signal of fertility reduction was emanated from the 1975 Pakistan Fertility Survey (PFS) which estimated a Total Fertility Rate (TFR) of 6.3 children from over 7 children estimated earlier from PGE data. However, all hopes of the onset of fertility transition were shattered by the [Retherford’s, et al. (1987)] study entitled “Fertility Trend in Pakistan: The Decline that Wasn’t”. By using the Own Children Method, they confirmed that the decline in fertility was an artifact of the data. Another study by Shah, Pullum, and Irfan (1986) also termed the fertility decline shown by the PFS data as spurious. The Pakistan Labour Force and Migration Survey, conducted five years later, in 1979-80, estimated a TFR of 6.5 children, thus providing another proof supporting the fact that fertility had not declined to the extent believed.

A 3-dimensional vascularized cardiac tri-culture model using chitosan nanofiber scaffolds

The development of an in vitro tissue model that can mimic the 3-dimenisonal (3-D) cellular architecture and mosaic of myocardial tissue holds great value for cardiac tissue engineering, modeling, and cardiovascular drug screening applications. The main objective of this project was to develop a 3-D vascularized cardiac tissue model in vitro for improved survival and function. The cellular mosaic of the myocardial tissue demands the intricate integration of an extracellular matrix-like scaffold, cellular constituents, and biological factors. The first aim of the research was to fabricate and characterize a biodegradable chitosan nanofiber scaffold that would resemble the extracellular matrix (ECM) physically and chemically. Chitosan, a natural polysaccharide that shares structural homology to the ECM glycosaminoglycans was processed into nanofibers via electrospinning to resemble the physical nano-architecture of the ECM. The second aim was to biologically modify the scaffold using a two step method: (1) Adsorption of fibronectin to improve cellular attachment and migration and (2) Induction of endothelial tubulogenesis to recreate the vascularized architecture of the myocardium. The third aim was to investigate the effect of co-culturing cardiomyocytes with fibroblasts on cardiomyocytes’ survival and contractility in the vascularized 3-D chitosan scaffold. This was based on the fact that 70% of the native myocardial tissue is composed of fibroblasts The chitosan scaffold was characterized for its physio-chemical properties, including in-vitro structural integrity and bio-degradability. The biomodification of the scaffold via fibronectin adsorption improved cellular attachment, verified by staining of actin (cytoskeletal protein) and vinculin (cell-adhesion protein). The endothelial cells formed a network of interconnected tubes and secreted GAGs that were immobilized onto the chitosan scaffold. The cellular studies showed that cardiomyocyte mono-cultures resulted in islands of isolated contractions and minimal gap junction expression. In addition, cardiomyocyte contractility was lost after four days in the mono-cultures. However, co-culturing the cardiomyocytes with the fibroblasts promoted tissue-like synchronous contractions that were sustained for over three weeks. Gap junction expression in cardiomyocytes-fibroblasts co-cultures was extensive and was expressed along the cardiomyocyte cell membranes. Finally, to create the cardiac tissue model, the vascularized chitosan nanofibers were impregnated with a co-culture system of cardiomyocytes and fibroblasts. Using real-time intracellular calcium ion staining, the cardiomyocytes were observed to have migrated through the 3-D chitosan scaffold and attained intercellular alignment to form cardiomyocyte tubules which is a characteristic of in vivo cardiomyocytes. The cardiomyocyte tubules were verified to contract in a synchronized and tissue-like rhythmic manner. These results highlight the immense importance of the vascular architecture and fibroblasts co-culture in the development of any cardiac regenerative therapy

Personal Smart Assistant for Digital Media and Advertisement

The expansion of the cyberspace and the enormous process in computing and software applications enabled technology to cover every aspect of our life, therefore, many of our goals are now technology driven. Consequently, the need of intelligent assistance to achieve these goals has increased. However, for this assistance to be beneficial for users, it should be targeted to them based on their needs and preferences. Intelligent software agents have been recognized as a promising approach for the development of user-centric, personalized, applications. In this thesis a generic personal smart assistant agent is proposed that provides relevant assistance to the user based on modeling his/her interests and behaviours. The main focus of this work is on developing a user behaviour model that captures the deliberative and reactive behaviours of the user in open environments. Furthermore, a prototype is built to utilize the personal assistant for personalized advertisement applications, where this assistant attempts to recommend the right advertisement to the right person at the right time

Edible Oil Deficit and Its Impact on Food Expenditure in Pakistan

This study is an attempt to analyze the impact of Edible Oil Deficit on Food Expenditure in Pakistan for the period 1971-2008. Edible oil deficit is one of the major concerns for the policy makers in Pakistan. Despite of having agriculture based economy; Pakistan is unable to fulfil her domestic demand of edible oil by local production. This situation forces the government to import edible oil and oil seeds from other countries. This import not only increases our balance of payment deficit but also it negatively affects the ability to finance the external debt repayments. Autoregressive Distributed Lag model has been used to analyse the long run relationship amongst the variables. Other important determinants of food expenditure along with edible oil deficit were also used to check for their collective long run impact. It was found that long run negative relationship exists between edible oil deficit and food expenditure and hence the result derives the policy implication that there is a need to boost up the efforts in the agriculture sector to steadily increase the local production of oil seeds in the country. The relationship between the per capita GDP and food expenditure is found to be positive and significant with elasticity of 0.261 suggesting that 1 percent increase in per capita GDP will cause food expenditure to increase by 0.26 percent. The relationship between food subsidy and food expenditure is found to be insignificant suggesting that due to improper targeting and consumer’s perception about quality and accessibility of subsidized food, Government’s food support programs are not effective.Edible Oil; Production; Imports; Trade Deficit; Balance of Payments; International Trade; Oilseed Crops; Agriculture; Pakistan; Edible oil deficit; demand function; food; inflation; food inflation; household expenditure.