413 research outputs found
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Nomad, a naval message understanding system
We are building systems to automatically analyze Navy messages. Such messages typically are terse and use many abbreviations and Navy jargon. As a result, they are more difficult to understand than everyday English.The NOMAD system interacts with a message sender to ensure that only unambiguous and reasonably correct messages are generated. The VOX system will allow a human tutor to interactively extend the knowledge base of NOMAD
Coherent control of three-spin states in a triple quantum dot
Spin qubits involving individual spins in single quantum dots or coupled
spins in double quantum dots have emerged as potential building blocks for
quantum information processing applications. It has been suggested that triple
quantum dots may provide additional tools and functionalities. These include
the encoding of information to either obtain protection from decoherence or to
permit all-electrical operation, efficient spin busing across a quantum
circuit, and to enable quantum error correction utilizing the three-spin
Greenberger-Horn-Zeilinger quantum state. Towards these goals we demonstrate
for the first time coherent manipulation between two interacting three-spin
states. We employ the Landau-Zener-St\"uckelberg approach for creating and
manipulating coherent superpositions of quantum states. We confirm that we are
able to maintain coherence when decreasing the exchange coupling of one spin
with another while simultaneously increasing its coupling with the third. Such
control of pairwise exchange is a requirement of most spin qubit architectures
but has not been previously demonstrated.Comment: 12 pages, 13 figures, and 2 table
Volatility forecasting in the Chinese commodity futures market with intraday data
Given the unique institutional regulations in the Chinese commodity futures market as well as the characteristics of the data it generates, we utilize contracts with three months to delivery, the most liquid contract series, to systematically explore volatility forecasting for aluminum, copper, fuel oil, and sugar at the daily and three intraday sampling frequencies. We adopt popular volatility models in the literature and assess the forecasts obtained via these models against alternative proxies for the true volatility. Our results suggest that the long memory property is an essential feature in the commodity futures volatility dynamics and that the ARFIMA model consistently produces the best forecasts or forecasts not inferior to the best in statistical terms
Rhodium Nanoparticle Shape Dependence in the Reduction of NO by CO
The shape dependence of the catalytic reduction of nitric oxide by carbon monoxide on rhodium nanopolyhedra and nanocubes was studied from 230 to 270 degrees C. The nanocubes are found to exhibit higher turnover frequency and lower activation energy than the nanopolyhedra. These trends are compared to previous studies on Rh single crystals.Chemistry, PhysicalSCI(E)EI21ARTICLE3-4317-32213
Economic Crisis and Investor Behaviour
This study investigates the effects of crises on domestic and foreign investors’ behaviours by utilizing a nonlinear approach. Considering the nonlinearity inherent in many financial variables, this study proposes an appropriate econometric modelling for analysing the investors’ behaviour, particularly during turbulent times. Specifically, STAR-STGARCH family models and generalized impulse response function analysis (GIRF) are employed to understand the different reactions of foreign and domestic investors at the Malaysian Stock Exchange market during the 1997 Asian crisis. The results of the model and the GIRF analysis have shown that foreign investors exhibited a herding behavior during the crisis and responded the shock more quickly than the domestic investors. When the same analysis is applied to understand the effects of the 2008 Subprime Mortgage Crisis in the Malaysian market, the behaviors of foreign and domestic investors are found to be very similar
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