The main objective of the thesis is to implement different architectures of 16-bit adders such as; Ripple CarryAdder (RCA), Manchester Carry Chain Adder (MCCA) and Kogge Stone Adder (KSA), in 65nm CMOS technology and to study their performance in terms of power, operating frequency and speed at near threshold operating regions. The performance of these adders are evaluated and compared with each other and a final conclusion is made as to which adder structure is more suitable for implementation in a 65nmtechnology for low power applications. Several optimisation techniques are performed for the adders to reduce the delay and power consumption. Propagation delay is the most critical or essential parameter to be considered, hence, to minimise the delay of the adder, a technique called sizing and ordering are required for the transistors. The purpose of the thesis is to make a fair comparison among adders over several metrics which include linearity, delay and power. Simulation results of MCCA achieved a greater significant performance upon or over RCA and KSA, and proved it is the best suitable adder for low power applications.

This thesis deals with modeling, simulation and operating limits of high-voltage direct-current (HVDC) transmission systems that employ voltage-source converters (VSCs) as their building blocks. This scheme is commonly known as the VSC-HVDC transmission. A simulation-based study is undertaken in which detailed electromagnetic transient (EMT) models are developed for a back-to-back VSC-HVDC transmission system. Different control strategies are implemented and their dynamic performances are investigated in the PSCAD/EMTDC EMT simulator. The research presented in this thesis firstly specifies the factors that limit the operating points of a VSC-HVDC system with particular emphasis on the strength of the terminating ac system. Although the EMT model shows these limits it provides little analytical reason for their presence and extent. A phasor-based quasi-steady state model of the system including the phase-locked loop firing control mechanism is proposed to determine and characterize the factors contributing to these operating limits. Stability margins and limits on the maximum available power are calculated, taking into consideration the maximum voltage rating of the VSC. The variations of ac system short-circuit ratio (SCR) and transformer impedance are proven to significantly impact the operating limits of the VSC-HVDC system. The results show how the power transfer capability reduces as the SCR decreases. The analysis shows that VSC-HVDC converters can operate into much weaker networks, and with less sensitivity, than the conventional line commutated converters (LCC-HVDC). Also for a given SCR the VSC-HVDC system has a significantly larger maximum available power in comparison with LCC-HVDC. A second research thrust of the thesis is introduction of a simplified converter model to reduce the computational intensity of its simulation. This is associated with the admittance matrix inversions required to simulate high-frequency switching of the converter valves. This simplified model is based on the concept of dynamic average-value modelling and provides the ability to generate either the full spectrum or the fundamental-frequency component of the VSC voltage. The model is validated against the detailed VSC-HVDC circuit and shows accurate matching during steady state and transient operation. Major reductions of 50-70% in CPU-time in repetitive simulation studies such as multiple runs and optimization-based controller tuning are achieved.

University, Diss., 2002--Saarbrücken.

Techn. University, Diss., 2004--Berlin.

The standard Keynesian view predicts that equalization of the income distribution leads to an increase in aggregate consumption. We revisit the analysis carried out by the seminal empirical contributions which test such a hypothesis using modern econometric methods and the most comprehensive dataset existing on income distribution measures. Our results indicate that there is no substantive empirical evidence of an effect of income inequality on aggregate consumption. (authors' abstract) / Series: Department of Economics Working Paper Series

The standard Keynesian view predicts that equalization of the income distribution leads to an increase in aggregate consumption. We revisit the analysis carried out by the seminal empirical contributions which test such a hypothesis using modern econometric methods and the most comprehensive dataset existing on income distribution measures. Our results indicate that there is no empirical evidence of a negative effect of income inequality on aggregate consumption.

abstract: During the past decade, different kinds of fancy functions are developed in portable electronic devices. This trend triggers the research of how to enhance battery lifetime to meet the requirement of fast growing demand of power in portable devices. DC-DC converter is the connection configuration between the battery and the functional circuitry. A good design of DC-DC converter will maximize the power efficiency and stabilize the power supply of following stages. As the representative of the DC-DC converter, Buck converter, which is a step down DC-DC converter that the output voltage level is smaller than the input voltage level, is the best-fit sample to start with. Digital control for DC-DC converters reduces noise sensitivity and enhances process, voltage and temperature (PVT) tolerance compared with analog control method. Also it will reduce the chip area and cost correspondingly. In battery-friendly perspective, current mode control has its advantage in over-current protection and parallel current sharing, which can form different structures to extend battery lifetime. In the thesis, the method to implement digitally average current mode control is introduced; including the FPGA based digital controller design flow. Based on the behavioral model of the close loop Buck converter with digital current control, the first FPGA based average current mode controller is burned into board and tested. With the analysis, the design metric of average current mode control is provided in the study. This will be the guideline of the parallel structure of future research. / Dissertation/Thesis / M.S. Electrical Engineering 2011

This study was concerned with the comparative relationship of attendance to grade point average. The first of five purposes was to determine if there was a relationship between adequate attendance and grade point average. The second and third purposes concerned the relationship between attendance and grade point average among students from different localities. The fourth and fifth purposes were to determine if there was a relationship between attendance and grade point average among students of different sex.

Orientador: Antônio Carlos Patrocinio / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica / Made available in DSpace on 2018-08-25T12:22:05Z (GMT). No. of bitstreams: 1 Pereira_JaksonDaCruz_M.pdf: 1462332 bytes, checksum: 393b1f36be156bf1cdedb16da1cc3fcd (MD5) Previous issue date: 2014 / Resumo: O presente trabalho se dedica ao estudo das médias aritmética, geométrica e harmônica. Inicialmente, definimos cada uma das médias e trabalhamos suas aplicações através da resolução de problemas. Posteriormente destacamos as desigualdades entre as médias e suas aplicações / Abstract: This dissertation is dedicated to the study of the arithmetic, geometric and harmonic means. Initially, we defined each of the means and applied its uses through problem resolution. Afterwards, we gave emphasis to the inequalities between the means and its uses / Mestrado / Matemática em Rede Nacional / Mestre em Matemática em Rede Nacional

For an ideal impact energy absorber, the initial peak force should be low and the average crushing force should be high. Also, a long stroke and a stable force history are expected. The thin-walled tube under axial loads is a kind of energy absorber that can produce controlled progressive collapse during a crash. It is a promising collapse mechanism for energy absorption with demonstrated success in industry. But the conventional thin-walled tubes still have high initial peak force and force fluctuations during a crushing process. To help to achieve a better energy absorbing structure, a research work has been carried out in this thesis. The aim of the present research is to achieve an improved understanding of the crushing behaviour of thin-walled tubes under axial loads. In the study, the entire crushing process, including the initial stage of collapse, its localization and the subsequent progressive folding has been carefully investigated by experiment. The relation between the localized plastic deformation and the corresponding crushing force is built by comparing the cross section of series of specimens and their load-displacement curves, which give a deep insight of the collapse mechanism of circular thin-walled tube under axial loads. Then some trigger systems are proposed, which is proved to be a good way to reduce the initial peak force and influence the collapse behaviour. To achieve higher energy absorbing efficiency, the multi-cell thin-walled tube has been investigated. Finally, based on the analysis in this study, a new multi-cell profile which is composed of coaxial tubes with different lengths and dented grooves is proposed. The new design is proved to be a good energy absorber with low initial peak force and very high energy absorption efficiency.