Combined Vertical And Lateral Channel Evolution Numerical Modeling

Vertical stream bed erosion has been studied routinely and its modeling is getting widespread acceptance. The same cannot be said with lateral stream bank erosion since its measurement or numerical modeling is very challenging. Bank erosion, however, can be important to channel morphology. It may contribute significantly to the overall sediment budget of a stream, is a leading cause of channel migration, and is the cause of major channel maintenance. However, combined vertical and lateral channel evolution is seldom addressed. In this study, a new geofluival numerical model is developed to simulate combined vertical and lateral channel evolution. Vertical erosion is predicted with a 2D depth-averaged model SRH-2D, while lateral erosion is simulated with a linear retreat bank erosion model developed in this study. SRH-2D and the bank erosion model are coupled together both spatially and temporally through a common mesh and the same time advancement. The new geofluvial model is first tested and verified using laboratory meander channels; good agreement are obtained between predicted bank retreat and measured data. The model is then applied to a 16-kilometer reach of Chosui River, Taiwan. Vertical and lateral channel evolution during a three-year period (2004 to 2007) is simulated and results are compared with the field data. It is shown that the geofluvial model correctly captures all major erosion and deposition patterns. The new model is shown to be useful for identifying potential erosion sites and providing information for river maintenance planning.

A Study On The Flow Characteristics Influenced By Hydraulic Structure At A Channel Junction

Natural riversare consisting of various networks as junction andstreams. And sediment and erosion are occurred by specific stream condition. When flood season,large discharge flew in the river and river bed changed by high flow velocity. Especially junction area’s flow characteristics are very complex. The purpose of this study is to analyze the flow characteristics in channel junction, which are most influenced by large discharge like flooding and input water from tributary. We investigate the flow characteristics by using hydrodynamics and transport module in MIKE 3 FM. MIKE 3 FM model was helpful tool to analysis 3D hydrodynamics, erosion and sediment effect from channel bed. We analyze flow characteristics at channel junction. Also we consider hydraulic structures like a bridge pier which is influencing flow characteristics like a flow velocity, water level, erosion and scour depth in channel bed. In the model, we controlled discharge condition according to Froude Number and reflect various grain diameter size and flow ratio change in main stream and tributary. In the result, flow velocity, water level, erosion and sediment depth are analyzed. Additionally, we suggest a these result relationship with equations. This study will help the understand flow characteristics and influence of hydraulic structure in channel junction. Acknowledgments This research was supported by a grant (12-TI-C01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

A Modular and digitally programmable interface based on band-pass sigma-delta modulator for mixed-signal systems-on-chip

The focus of this thesis is to discuss the development and modeling of an interface architecture to be employed for interfacing analog signals in mixed-signal SOC. We claim that the approach that is going to be presented is able to achieve wide frequency range, and covers a large range of applications with constant performance, allied to digital configuration compatibility. Our primary assumptions are to use a fixed analog block and to promote application configurability in the digital domain, which leads to a mixed-signal interface. The use of a fixed analog block avoids the performance loss common to configurable analog blocks. The usage of configurability on the digital domain makes possible the use of all existing tools for high level design, simulation and synthesis to implement the target application, with very good performance prediction. The proposed approach utilizes the concept of frequency translation (mixing) of the input signal followed by its conversion to the ΣΔ domain, which makes possible the use of a fairly constant analog block, and also, a uniform treatment of input signal from DC to high frequencies. The programmability is performed in the ΣΔ digital domain where performance can be closely achieved according to application specification. The interface performance theoretical and simulation model are developed for design space exploration and for physical design support. Two prototypes are built and characterized to validate the proposed model and to implement some application examples. The usage of this interface as a multi-band parametric ADC and as a two channels analog multiplier and adder are shown. The multi-channel analog interface architecture is also presented. The characterization measurements support the main advantages of the approach proposed.

Investment coordination failures and the confidence channel of fiscal policy

Este trabalho desenvolve um novo "canal de Confiança" da política fiscal e caracteriza a política ótima quando esse canal é levado em consideração. Para esse objetivo, utilizamos um modelo estático com (i) concorrência monopolística, (ii) custos de ajustamento fixos para investir, (iii) complementaridade estratégica devido a informação imperfeita com respeito a produtividade agregada, e (iv) bens privados como substitutos imperfeitos de bens privados. Este arcabouço acomoda a possibilidade de falhas de coordenação nos investimentos, mas apresenta um equilíbrio único. Mostramos que a política fiscal tem efeitos importantes na coordenação. Um aumento dos gastos do governo leva a uma maior demanda por bens privados. Mais importante, este também afeta as expectativas de ordem superior com relação a demanda das demais firmas, que amplifica os efeitos do aumento inicial da demanda devido a complementaridade estratégica nas decisões de investimento. Como as demais firmas estão se deparam com uma demanda maior, espera-se que estas invistam mais, que por sua vez, aumenta a demanda individual de cada firma, que aumenta os incentivos a investir. Denominamos isto como o "canal de confiança" da política fiscal. Sob a ameaça de falhas de coordenação, a política fiscal ótima prescreve produzir além do ponto em que o benefício marginal resultante do consumo de bens públicos é igual ao custo marginal desses bens. Este benefício adicional vem do fato de que a política fiscal pode ampliar a coordenação dos investimentos.

Essays on the credit channel of monetary policy: a case study for Brazil

The onset of the financial crisis in 2008 and the European sovereign crisis in 2010 renewed the interest of macroeconomists on the role played by credit in business cycle fluctuations. The purpose of the present work is to present empirical evidence on the monetary policy transmission mechanism in Brazil with a special eye on the role played by the credit channel, using different econometric techniques. It is comprised by three articles. The first one presents a review of the literature of financial frictions, with a focus on the overlaps between credit activity and the monetary policy. It highlights how the sharp disruptions in the financial markets spurred central banks in developed and emerging nations to deploy of a broad set of non conventional tools to overcome the damage on financial intermediation. A chapter is dedicated to the challenge face by the policymaking in emerging markets and Brazil in particular in the highly integrated global capital market. This second article investigates the implications of the credit channel of the monetary policy transmission mechanism in the case of Brazil, using a structural FAVAR (SFAVAR) approach. The term “structural” comes from the estimation strategy, which generates factors that have a clear economic interpretation. The results show that unexpected shocks in the proxies for the external finance premium and the credit volume produce large and persistent fluctuations in inflation and economic activity – accounting for more than 30% of the error forecast variance of the latter in a three-year horizon. Counterfactual simulations demonstrate that the credit channel amplified the economic contraction in Brazil during the acute phase of the global financial crisis in the last quarter of 2008, thus gave an important impulse to the recovery period that followed. In the third articles, I make use of Bayesian estimation of a classical neo-Keynesian DSGE model, incorporating the financial accelerator channel developed by Bernanke, Gertler and Gilchrist (1999). The results present evidences in line to those already seen in the previous article: disturbances on the external finance premium – represented here by credit spreads – trigger significant responses on the aggregate demand and inflation and monetary policy shocks are amplified by the financial accelerator mechanism. Keywords: Macroeconomics, Monetary Policy, Credit Channel, Financial Accelerator, FAVAR, DSGE, Bayesian Econometrics

Robust monetary policy with the consumption - wealth channel

Robust Monetary Policy with the Consumption - Wealth Channel

How children's television networks in the United States have adapted to the changing digital habits of their young audiences: A comparative analysis between the Disney Channel and Nickelodeon

In the contemporary societies, many children are drawn to digital media, using it in ways that were initially unfathomable. Changing digital habits among young children have been affiliated to the rapid development, witnessed in the technological field. Prevalently, new forms of technology are being developed and ingrained into young children’s day-to-day activities. The emergence of new forms of technology has in turn prompted significant changes in digital and media consumption particularly, among young children. Changes in media and digital consumption have in turn instigated linear transition in the analogue media industries. This has resulted in analogue media networks working towards digitalizing their industries in a manner that will befit changing digital habits among young children. This report aims at establishing and analyzing the different ways in which children’s digital habits have changed and revolutionized. To achieve this, the report will critically examine the existing scope of knowledge, with reference to changing digital habits among young audiences. Further, the report also aims at establishing the manner in which children television networks have adapted to the changing digital habits among young audiences. To achieve this, the report will focus on two children television networks, Disney channel, and Nickelodeon. After which, a comparative analysis will be conducted to establish the changes made by each of these television channels, with the aim of adapting to the new digital habits among children.

Formulação de bloco intertravado cerâmico com adição de resíduos urbanos e industriais

The production of waste from urban and industrial activities is one of the factors of environmental contamination and has aroused attention of the scientific community, in the sense of its reuse. On the other hand, the city of Salvador/Ba, with approximately 262 channels, responsible for storm water runoff, produces every year, by the intervention of cleaning and clearing channels, a significant volume of sediments (dredged mud), and thus an appropriate methodology for their final destination. This study aims to assess the influence of incorporation of these tailings in arrays of clay for production of interlocked block ceramic, also known as ceramic paver. All the raw materials from the metropolitan region of Salvador (RMS) were characterized by x-ray fluorescence, x-ray diffraction, thermal analysis (TG and TDA), particle size analysis and dilatometry. With the use of statistical experimental planning technique, ternary diagram was defined in the study region and the analyzed formulations. The specimens were prepared with dimensions of 60x20x5mm³, by uniaxial pressing of 30 MPa and after sintering at temperatures of 900°, 1000º and 1100ºC the technological properties were evaluated: linear shrinkage, water absorption, apparent porosity, apparent specifies mass, flexural rupture and module. For the uniaxial compression strength used cylindrical probe body with Ø 50 mm. The standard mass (MP) was prepared with 90% by weight of clay and 10% by weight of Channel sediment (SCP), not being verified significant variations in the properties of the final product. With the incorporation of 10% by weight of manganese residue (PFM) and 10% by weight of the Ceramic waste (RCB) in the mass default, in addition to adjusting the plasticity due to less waste clay content, provided increased linear firing shrinkage, due the significant concentration of K2O, forming liquid phase at low temperature, contributing to decreased porosity and mechanical resistance, being 92,5 MPa maximum compressive strength verified. After extract test leachate and soluble, the piece containing 10% of the PFM, was classified as non-hazardous and inert material according to NBR10004/04 ABNT. The results showed the feasibility on using waste, SCP, RCB and PFM clay mass, at temperatures above 900ºC, paver ceramic production, according to the specifications of the technical standards, so that to exceed the 10% of the PFM, it becomes imperative to conduct studies of environmental impacts

Haematological and biochemical reference intervals for farmed channel catfish

The reference intervals for biochemical variables and red blood cell indices of healthy intensively bred channel catfish Ictalurus punctatus were determined. The blood variables were determined using standardized clinical methods. The reference intervals (25th and 75th percentiles) were established using a non-parametric method. Reference intervals for plasma glucose, serum total protein, sodium, potassium, calcium, magnesium, chloride concentration, primary and secondary red blood cell indices were established. The haematological and biochemical reference intervals established may allow important clinical decisions about channel catfish. (c) 2007 the Authors Journal compilation (C) 2007 the Fisheries Society of the British Isles.

Group Sequential Communication (GSC): Especificação e Análise de Desempenho de umMecanismo de Comunicação de Tempo Real Compatível ao Padrão IEEE 802.11/11e Aplicado à Automação Industrial

This thesis proposes the specification and performance analysis of a real-time communication mechanism for IEEE 802.11/11e standard. This approach is called Group Sequential Communication (GSC). The GSC has a better performance for dealing with small data packets when compared to the HCCA mechanism by adopting a decentralized medium access control using a publish/subscribe communication scheme. The main objective of the thesis is the HCCA overhead reduction of the Polling, ACK and QoS Null frames exchanged between the Hybrid Coordinator and the polled stations. The GSC eliminates the polling scheme used by HCCA scheduling algorithm by using a Virtual Token Passing procedure among members of the real-time group to whom a high-priority and sequential access to communication medium is granted. In order to improve the reliability of the mechanism proposed into a noisy channel, it is presented an error recovery scheme called second chance algorithm. This scheme is based on block acknowledgment strategy where there is a possibility of retransmitting when missing real-time messages. Thus, the GSC mechanism maintains the real-time traffic across many IEEE 802.11/11e devices, optimized bandwidth usage and minimal delay variation for data packets in the wireless network. For validation purpose of the communication scheme, the GSC and HCCA mechanisms have been implemented in network simulation software developed in C/C++ and their performance results were compared. The experiments show the efficiency of the GSC mechanism, especially in industrial communication scenarios.

Modelo 2,5D de predição de propagação para ambientes interiores utilizando o método do traçado de raios

A 2.5D ray-tracing propagation model is proposed to predict radio loss in indoor environment. Specifically, we opted for the Shooting and Bouncing Rays (SBR) method, together with the Geometrieal Theory of Diffrartion (GTD). Besides the line-of-sight propagation (LOS), we consider that the radio waves may experience reflection, refraction, and diffraction (NLOS). In the Shooting and Bouncing Rays (SBR) method, the transmitter antenna launches a bundle of rays that may or may not reach the receiver. Considering the transmitting antenna as a point, the rays will start to launch from this position and can reach the receiver either directly or after reflections, refractions, diffractions, or even after any combination of the previous effects. To model the environment, a database is built to record geometrical characteristics and information on the constituent materials of the scenario. The database works independently of the simulation program, allowing robustness and flexibility to model other seenarios. Each propagation mechanism is treated separately. In line-of-sight propagation, the main contribution to the received signal comes from the direct ray, while reflected, refracted, and diffracted signal dominate when the line-of-sight is blocked. For this case, the transmitted signal reaches the receiver through more than one path, resulting in a multipath fading. The transmitting channel of a mobile system is simulated by moving either the transmitter or the receiver around the environment. The validity of the method is verified through simulations and measurements. The computed path losses are compared with the measured values at 1.8 GHz ftequency. The results were obtained for the main corridor and room classes adjacent to it. A reasonable agreement is observed. The numerical predictions are also compared with published data at 900 MHz and 2.44 GHz frequencies showing good convergence

Modelagem em SystemC-AMS de uma plataforma compatível com o sistema de coleta de dados brasileiro

This work presents simulation results of an identification platform compatible with the INPE Brazilian Data Collection System, modeled with SystemC-AMS. SystemC-AMS that is a library of C++ classes dedicated to the simulation of heterogeneous systems, offering a powerful resource to describe models in digital, analog and RF domains, as well as mechanical and optic. The designed model was divided in four parts. The first block takes into account the satellite s orbit, necessary to correctly model the propagation channel, including Doppler effect, attenuation and thermal noise. The identification block detects the satellite presence. It is composed by low noise amplifier, band pass filter, power detector and logic comparator. The controller block is responsible for enabling the RF transmitter when the presence of the satellite is detected. The controller was modeled as a Petri net, due to the asynchronous nature of the system. The fourth block is the RF transmitter unit, which performs the modulation of the information in BPSK ±60o. This block is composed by oscillator, mixer, adder and amplifier. The whole system was simulated simultaneously. The results are being used to specify system components and to elaborate testbenchs for design verification