Optimal control of topological quantum systems

Topological quantum computation provides an architecture for encoding quantum information in such a way as to be theoretically robust to local noise. Logical qubits are encoded in topological degrees of freedom typically in spin-lattice models. Excitations in the spin-lattice models manifest as anyons, generalisations of bosons and fermions that exist in two dimensions. Proposals for experimental realisation of these topological systems have previously relied on perfect anyon creation in a time independent-manner or in the case of time-dependent proposals have primarily relied on adiabatic, therefore slow, dynamics. The aim of this thesis is to use quantum control to create anyons and encode logical qubits in topological systems without the requirement for adiabaticity and long timescales. First, we demonstrate the creation of abelian anyons using time-dependent controls in the toric code model, a system that is useful as a quantum memory. We show that this may be done within arbitrarily short timescales at the expense of larger magnitude control pulses. Additionally, we investigate the robustness of our protocol in the face of theoretical errors in anyon creation. Secondly, we investigate the creation of non-abelian anyons in the Kitaev honeycomb model. By fermionising a time-dependent version of the model we demonstrate how optimal control theory can allow for anyon creation in faster-than-adiabatic time. Moreover, we show that the particular method we develop to achieve this scales only linearly in the number of spins in the lattice. Thirdly, we investigate defect creation in the surface code, a generalisation of the toric code that does not require periodic boundary conditions. Optimal quantum control is used to show how defects may be created faster than with the typical adiabatic procedures. Additionally, a method using mapping of dynamical Lie algebras is used to demonstrate that optimal control techniques may be extended to operations whose dynamics require solving in a large Hilbert space.Open Acces

Simulation of Three-Phase Induction Motor Control Using Fuzzy Logic Controller

A fuzzy logic controller has been developed and simulated on an indirect vector control of an induction motor (IVCIM) drive system. The objective of the indirect vector control is to convert the three-phase induction motor into a linear device where the torque and the flux in the motor can be controlled independently. The induction motor is fed by a current-controlled PWM inverter. The proposed fuzzy speed controller block in a vector controlled drive system observes the pattern of the speed loop error signal and correspondingly updates its output, so that the actual speed matches the command speed. The design of the fuzzy controller starts with identifying the inputs, performing the membership functions for the two inputs of the FLC and ends at manipulating the final command signal to the current regulator which triggers the inverter.The fuzzy logic toolbox has been used to build the fuzzy inference system (FIS) which is the dynamo of the fuzzy logic controller. The proposed FLC controller has been designed to meet the speed tracking requirements under a step change in speed and load changes. The proposed FLC drive dynamic performance has been investigated and tested under different operating conditions by simulation in the SimulinMMatlab software environment. In order to prove the superiority of the FLC, a conventional PI controller based IM drive system has also been simulated. The simulation results obtained have proved the very good performance and robustness of the proposed FLC. It is concluded that the proposed fuzzy logic controller has shown superior performances over the conventional PI controller

Factors that influence oral presentations of engineering students of Pakistan for workplace environment

Oral presentations have acquired significant importance in the world of work especially in the field of engineering. Industry demands a new type of engineer equipped with new competencies and skills to promote business of organizations. Twenty five (25) engineering students from 2 engineering universities of Pakistan participated in this study. Purposive sampling method was used for data collection since participants were selected on specific criteria of only final year engineering students. All presentations were video recorded to capture actual barriers than perceived barriers of engineering students. Data were analyzed qualitatively through oral presentation assessment rubric. This assessment rubric contained four traits such as presentation skill, confidence, nervousness and vocal variety. Three assessors assessed these oral presentations in order to overcome researcher bias. The results of the study indicated that poor presentation skill, poor confidence and nervousness influenced effective oral presentation performance of engineering students. The findings of the study can be used as a guideline to prepare better human capital for workforce which is demand of modern industry to increase its workplace productivity

Corporate Integrity System: Comparative Analysis of Two Giant Government Linked Companies

AbstractThis study aims to assess the level of companies’ commitment to comply with a corporate integrity system in their day to day operation. Based on 105 and 230 questionnaire distributed and received from employees in Company A and Company B respectively, the findings revealed that for Infrastructure dimension, both GLCs score below 50% indicating that these companies may need to invest in financial and intangible resources annually to the ethic function as a part of organization's budget cycle. Overall, both companies score more than 50% indicating their progress towards higher level of corporate integrity system

Dividend policy and payout practices in Malaysia : a qualitative analysis

Since stock prices reflect the firm’s future earnings potentials (Miller and Rock, 1985), dividends announcements therefore convey new information to the market about the future prospects of the corporation. As such, the objective of the current study is to examine the potential role that dividend payouts play in influencing the fund managers and investors in recommending or selecting a stock, and for various stocks’ performance assessment. In addition, the study attempts to examine the possible effect of taxation on dividends payout. The study uses qualitative methods in form of semi structured interviews conducted with six Malaysian investment managers. The findings revealed that dividend payouts are not solely used as a basis for stock recommendation and assessment of companies’ performance by fund managers in Malaysia. Furthermore, taxation was found to be significant in determining dividend payouts by companies in Malaysia. These findings have great contributions to the dividend policy theory, as well as to the practitioners and policy makers that are discussed in details at the end of the paper.peer-reviewe

Surface Modification of Titanium Foil Substrates in Experimental Solar Cells

A case study involving surface smoothing of titanium foil was obtained from a solar cell research company. It was believed that the rougher surface of metals was responsible for low solar cell efficiency when using titanium foil rather than glass as a substrate. A method was needed to reduce the surface asperity height of the titanium foil from the existing 1 μm to less than 0.1 μm. Several methods were investigated. The recommended method was the use of an excimer laser, a laser powered by excited noble gas-halide molecules as a lasing medium

Tradition and Perspectives of Arab Herbal Medicine: A Review

Complementary and Alternative Medicine (CAM), including herbal medicine, are popular in the general population worldwide. Parallel to the increasing interest in ‘modern’ CAM therapies and the historical importance of Arab medicine, there is also a similar trend in research activities dealing with the efficacy and safety of medicinal plants in our region. Historical and current studies and surveys indicate that the Eastern region of the Mediterranean has been distinguished throughout the generations with a rich inventory of natural medicinal herbs. It is well documented that indigenous Arab medicine has contributed greatly to the development of modern medicine in Europe and remains one of the closest forms of original European medicine. The rapid increase in consumption of herbal remedies worldwide has been stimulated by several factors, including the notion that all herbal products are safe and effective. This article presents a systematic review on traditional Arab medicine including historical background, medical innovations introduced by Arab physicians in the field of safety and efficacy of herbal medicine and a state-of-the-art description of traditional Arab herbal medicine in the Mediterranean region

Pembangunan tanah & halangannya

Pembangunan tanah merupakan penggerak utama pembangunan negara. Namun, pembangunan tanah melibatkan proses yang rumit. Antara puncanya adalah terdapat pelbagai halangan yang boleh menyebabkan pembangunan tanah tidak dapat dijalankan. Secara umum, halangan pembangunan tanah boleh dikategorikan mengikut faktor sosial, ekonomi, dan perundangan. Halangan pembangunan boleh juga dikategorikan secara faktor luaran dan dalaman. Kajian literatur menunjukkan secara amnya halangan pembangunan tanah boleh dibahagikan kepada halangan luaran dan halangan dalaman. Kajian literatur tentang faktor dalaman menumpu pada sikap pemilik dan pihak yang berkepentingan. Faktor luaran pula termasuklah undang-undang pembangunan tanah yang berkaitan. Selain faktor luaran dan dalaman, kehendak dan keperluan penduduk dalam memajukan tanah mereka perlu diberi perhatian. Kajian empirik yang dijalankan di Pulau Duyong, Kuala Terengganu menunjukkan matlamat kerajaan untuk melihat pembangunan tanah yang diberi milik tidak kesampaian kerana halangan luaran dan sikap pemilik serta penduduk setempat yang dipengaruhi oleh persepsi, motif, dan strategi mereka. Penduduk juga ingin mengekalkan persekitaran sedia ada sebagai keperluan penduduk setempat. Buku ini sesuai sebagai rujukan kepada pelajar di institusi pengajian tinggi terutamanya dalam bidang alam bina, pembinaan, bangunan, seni bina, ukur tanah, ukur bahan, penilaian harta, pentadbiran dan pembangunan tanah, perancangan bandar, dan perumahan serta pembaca umum yang berminat untuk meningkatkan pengetahuan dalam bidang pembangunan tanah

Negative Outcomes of Teen Sexual Activity: Is There a Regional Effect?

A recent victory with respect to teen sexual behavior is the reduction of the national teen birth rate. In 1991, there were 61.8 births per 1000 females aged 15-19. By 2014, this rate plummeted to 24.2 births per 1000 adolescent females. Averages, however, do not reflect state-level variation. For example, in 2014, Kentucky reported 35.3 births per 1000 adolescent females, while New York reported a teen birth rates of 16.1 births per 1000 adolescent females. This report asks: are these discrepancies due to regional factors, and are these differences statistically significant? To examine rural and urban differences in outcomes of teen sexual behavior, data from two rural states (Kentucky and Tennessee) and two urban states (New York and Florida) were analyzed. The results suggest significant differences in teenage sexual behaviour outcomes between and within states. For example, whilst teenage pregnancy rates were similar in all states, abortion rates were significantly lower and birth rates were higher in rural than urban states, suggesting possible differentials in health, social, and economic policies between states