908 resultados para non-linear dynamic system and DDoS
Resumo:
A 560-meter-thick sequence of Cenomanian through Pleistocene sediments cored at DSDP Site 462 in the Nauru Basin overlies a 500-meter-thick complex unit of altered basalt flows, diabase sills, and thin intercalated volcaniclastic sediments. The Upper Cretaceous and Cenozoic sediments contain a high proportion of calcareous fossils, although the site has apparently been below the calcite compensation depth (CCD) from the late Mesozoic to the Pleistocene. This fact and the contemporaneous fluctuations of the calcite and opal accumulation rates suggest an irregular influx of displaced pelagic sediments from the shallow margins of the basin to its center, resulting in unusually high overall sedimentation rates for such a deep (5190 m) site. Shallow-water benthic fossils and planktonic foraminifers both occur as reworked materials, but usually are not found in the same intervals of the sediment section. We interpret this as recording separate erosional interludes in the shallow-water and intermediate-water regimes. Lower and upper Cenozoic hiatuses also are believed to have resulted from mid-water events. High accumulation rates of volcanogenic material during Santonian time suggest a corresponding significant volcanic episode. The coincidence of increased carbonate accumulation rates during the Campanian and displacement of shallow-water fossils during the late Campanian-early Maestrichtian with the volcanic event implies that this early event resulted in formation of the island chains around the Nauru Basin, which then served as platforms for initial carbonate deposition.
Resumo:
We examine the potential impact of TTIP through trade-cost reductions, applying a mix of econometric and computational methods to develop estimates of the benefits (and costs) for the EU, United States, and third countries. Econometric results point to an approximate 80% growth in bilateral trade with an ambitious trade agreement. However, at the same time, computable general equilibrium (CGE) estimates highlight distributional impacts across countries and factors not evident from econometrics alone. Translated through our CGE framework, while bilateral trade increases roughly 80%, there is a fall of about 2.5% in trade with the rest of the world in our central case. The estimated gains in annual consumption range between 1% and 2.25% for the United States and EU, respectively. A purely discriminatory agreement would harm most countries outside the agreement, while the direction of third-country effects hinges critically on whether NTB reductions end up being discriminatory or not. Within the United States and EU, while labour gains across skill categories, the impact on farmers is mixed.
Resumo:
Creating a rice marketing system has been one of the central policy issues in Myanmar's move to a market economy since the end of the 1980s. Two liberalizations of rice marketing were implemented in 1987 and 2003. This paper examines the essential aspects of the liberalizations and the subsequent transformation of Myanmar's rice marketing sector. It attempts to bring into clearer focus the rationale of the government's rice marketing reforms which is to maintain a stable supply of rice at a low price to consumers. Under this rationale, however, the state rice marketing sector continued to lose efficiency while the private sector was allowed to develop on condition that it did not jeopardize the rationale of stable supply at low price. The paper concludes that the prospect for the future development of the private rice marketing sector is dim since a change in the rice market's rationale is unlikely. Private rice exporting is unlikely to be permitted, while the domestic market is approaching the saturation point. Thus, there is little momentum for the private rice sector to undertake any substantial expansion of investment.
Resumo:
Current nanometer technologies suffer within-die parameter uncertainties, varying workload conditions, aging, and temperature effects that cause a serious reduction on yield and performance. In this scenario, monitoring, calibration, and dynamic adaptation become essential, demanding systems with a collection of multi purpose monitors and exposing the need for light-weight monitoring networks. This paper presents a new monitoring network paradigm able to perform an early prioritization of the information. This is achieved by the introduction of a new hierarchy level, the threshing level. Targeting it, we propose a time-domain signaling scheme over a single-wire that minimizes the network switching activity as well as the routing requirements. To validate our approach, we make a thorough analysis of the architectural trade-offs and expose two complete monitoring systems that suppose an area improvement of 40% and a power reduction of three orders of magnitude compared to previous works.
Application of the Extended Kalman filter to fuzzy modeling: Algorithms and practical implementation
Resumo:
Modeling phase is fundamental both in the analysis process of a dynamic system and the design of a control system. If this phase is in-line is even more critical and the only information of the system comes from input/output data. Some adaptation algorithms for fuzzy system based on extended Kalman filter are presented in this paper, which allows obtaining accurate models without renounce the computational efficiency that characterizes the Kalman filter, and allows its implementation in-line with the process
Resumo:
A large number of reinforced concrete (RC) frame structures built in earthquake-prone areas such as Haiti are vulnerable to strong ground motions. Structures in developing countries need low-cost seismic retrofit solutions to reduce their vulnerability. This paper investigates the feasibility of using masonry infill walls to reduce deformations and damage caused by strong ground motions in brittle and weak RC frames designed only for gravity loads. A numerical experiment was conducted in which several idealized prototypes representing RC frame structures of school buildings damaged during the Port-au-Prince earthquake (Haiti, 2010) were strengthened by adding elements representing masonry infill walls arranged in different configurations. Each configuration was characterized by the ratio Rm of the area of walls in the direction of the ground motion (in plan) installed in each story to the total floor area. The numerical representations of these idealized RC frame structures with different values of Rm were (hypothetically) subjected to three major earthquakes with peak ground accelerations of approximately 0.5g. The results of the non-linear dynamic response analyses were summarized in tentative relationships between Rm and four parameters commonly used to characterize the seismic response of structures: interstory drift, Park and Ang indexes of damage, and total amount of energy dissipated by the main frame. It was found that Rm=4% is a reasonable minimum design value for seismic retrofitting purposes in cases in which available resources are not sufficient to afford conventional retrofit measures.