3,266 research outputs found
Electron confinement by laser-driven azimuthal magnetic fields during direct laser acceleration
A laser-driven azimuthal plasma magnetic field is known to facilitate
electron energy gain from the irradiating laser pulse. The enhancement is due
to changes in the orientation between the laser electric field and electron
velocity caused by magnetic field deflections. Transverse electron confinement
is critical for realizing this concept experimentally. We find that the phase
velocity of the laser pulse has a profound impact on the transverse size of
electron trajectories. The transverse size remains constant below a threshold
energy that depends on the degree of the superluminosity and it increases with
the electron energy above the threshold. This increase can cause electron
losses in tightly focused laser pulses. We show using 3D particle-in-cell
simulations that the electron energy gain can be significantly increased by
increasing laser power at fixed intensity due to the increased electron
confinement. This finding makes a strong case for designing experiments at
multi-PW laser facilities
Anti-Windup Design for Internal Model Control
This paper considers linear control design for systems with input magnitude saturation. A general anti-windup scheme which optimizes nonlinear performance, applicable to MIMO systems, is developed. Several examples, including an ill-conditioned plant, show that the scheme provides graceful degradation of performance. The attractive features of this scheme are its simplicity and effectiveness
Automatic evaluation of contractual terms
This disclosure describes use of machine learning and natural language processing techniques to assist users in reviewing terms and conditions (T&C), e.g., provided by online product and service providers. A database of T&C is created and indexed according to factors such as country, industry, application, etc. The database is utilized to identify T&C content that is common for a given industry application in a specific jurisdiction. When a user provides permission to analyze and provide assistance for a T&C document, such document is analyzed to determine a risk score. Further, any anomalous content in the T&C is flagged. The user is provided options to conduct in-depth review of the T&C, and to accept or decline various terms. When user permit, individual preferences for various terms are stored and matched to the T&C document
An analysis of various policy instruments to reduce congestion, fuel consumption and CO2 emissions in Beijing
Using a nested multinomial logit model of car ownership and personal travel in Beijing circa 2005, this paper compares the effectiveness of different policy instruments to reduce traffic congestion and CO2 emissions. The study shows that a congestion toll is more efficient than a fuel tax in reducing traffic congestion, whereas a fuel tax is more effective as a policy instrument for reducing gasoline consumption and emissions. An improvement in car efficiency would also reduce congestion, fuel consumption, and CO2 emissions significantly; however, this policy benefits only richer households that own a car. Low-income households do better under the fuel tax policy than under the efficiency improvement and congestion toll policies. The congestion toll and fuel tax require the travel cost per mile to more than triple. The responsiveness of aggregate fuel and CO2 are, approximately, a 1 percent drop for each 10 percent rise in the money cost of a car trip.Transport Economics Policy&Planning,Airports and Air Services,Roads&Highways,Transport and Environment,Transport in Urban Areas,Urban Transport
Marketing alternative fueled automobiles
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 37-38).Marketing alternative fueled vehicles is a difficult challenge for automakers. The foundation of the market, the terms of competition, and the customer segments involved are still being defined. But automakers can draw lessons from other industries, previous examples, and recent launches of the Chevy Volt and Nissan Leaf to help guide them. Automakers can deploy new marketing tools to advance their understanding of the market, define the terms of competition, and listen in to their customers' needs. These new tools can help reduce the risk and uncertainty involved with launching new products like alternative fueled vehicles. This thesis explores the major issues in marketing alternative fueled automobiles in several major parts. First it will look at the major drivers of alternative fueled vehicles and historical examples such as the Prius. While the market continues to change with each year, some trends emerge as key to defining the future of the industry. Second, it will look at the current strategic environment for alternative fueled vehicles, including an exploration of the various fuel types and vehicle offerings. Third, it will offer lessons learned for manufacturers based on the case study work done with two automotive manufacturers on real-life launches of a plug-in hybrid and a hydrogen vehicle. Some classical marketing frameworks, such as the innovation cycle, are used to help understand current puzzles, and new tools, such as semantic/perceptual maps, are used to help understand how open questions might be resolved in the next few years. Finally, it will explore a novel modeling tool developed for assessing potential adoption rates for alternative fueled vehicles by looking at costs and profits from both the owners and automakers' perspective.by Alex Zheng.M.B.A
Automatic translation and transcription of voicemail
This disclosure describes automatic translation and transcription of foreign language voicemails into a language of a user’s choice. Language detection, translation, and transcription techniques are employed to generate the text transcript in the preferred language. The user is provided a text transcript of voicemail in their preferred language with an indication that the voicemail was translated
Speculative Trading, Prospect Theory and Transaction Costs
A speculative agent with Prospect Theory preference chooses the optimal time
to purchase and then to sell an indivisible risky asset to maximize the
expected utility of the round-trip profit net of transaction costs. The
optimization problem is formulated as a sequential optimal stopping problem and
we provide a complete characterization of the solution. Depending on the
preference and market parameters, the optimal strategy can be ``buy and hold'',
``buy low sell high'', ``buy high sell higher'' or ``no trading''. Behavioral
preference and market friction interact in a subtle way which yields surprising
implications on the agent's trading patterns. For example, increasing the
market entry fee does not necessarily curb speculative trading, but instead it
may induce a higher reference point under which the agent becomes more
risk-seeking and in turn is more likely to trade
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