133 research outputs found

    Signal analysis of impulse response functions in MR- and CT-measurements of cerebral blood flow

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    The impulse response function (IRF) of a localized bolus in cerebral blood flow codes important information on the tissue type. It is indirectly accessible both from MR- and CT-imaging methods, at least in principle. In practice, however, noise and limited signal resolution render standard deconvolution techniques almost useless. Parametric signal descriptions look more promising, and it is the aim of this contribution to develop some improvements along this line.Comment: 15 pages, 6 figure

    Why Do Computers Depreciate?

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    The value of installed computers falls rapidly and therefore computers have a very high user cost. The paper provides a complete account of the non-financial user cost of personal computers -- decomposing it into replacement cost change, obsolescence, instantaneous depreciation, and age-related depreciation. The paper uses data on the resale price of computers and a hedonic price index for new computers to achieve this decomposition. Once obsolescence is taken into account, age-related depreciation -- which is often identified as deterioration -- is estimated to be negligible. While the majority of the loss in value of used computers comes from declines in replacement cost, this paper shows the second most important source of decline in value is obsolescence. Obsolescence is accelerated by the decline in replacement cost of computers. Cheaper computing power drives developments in software and networks that make older computers less productive even though their original functionality remains intact.

    Judges, Prosecutors, Jurors, and Organized Labor: Four Perspectives of Corporate Citizenship

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    Some people argue that the civil jury is in decline. They argue that it\u27s not really so important to be focusing on jurors and jurors\u27 views about corporate responsibility as it might have been in prior times. I want to raise some arguments in favor of the continuing importance of the civil jury. First of all, the cases that juries try may be very important cases in terms of the company and in terms of the role of the company vis-a-vis government regulation. Jurors are symbolic representatives of the public in the courtroom. Finding out what juries do when they look at the facts of the case, a missing memo, or a corporate executive explaining a memo, can give the parties an idea about what laypeople generally think about corporate action. Most important, the fact that we have a jury in some cases makes a difference in all the rest of the cases in the civil docket that settle rather than go to trial. Civil jury trial verdicts send signals to lawyers, judges, and companies about how the public perceives corporate behavior. So, in my view, it\u27s important to take a look at how juries think about issues of corporate responsibility in part to get a sense of public understanding of it and in part to understand how a jury might decide a specific case. From one perspective, the civil jury is seen as a modern-day Robin Hood. The civil jury is thought to be extraordinarily pro-plaintiff and quite anti-business. It is said to operate with a deep pockets approach. I put some of these beliefs about the jury to the test. In a nutshell, I found that the widespread beliefs about the civil jury in business cases are nearly as mythic as Robin Hood. In contrast to prevailing beliefs, the jurors I interviewed surprised me by being rather tough on plaintiffs who bring cases against businesses and corporations. Second, and this was also something of a surprise, I didn\u27t find a lot of anti-business prejudice. I asked participants in all of my studies a question about the appropriate standard for corporate responsibility: Should corporations be held to a higher standard of responsibility compared to individuals? I found that a number of people believed in similar treatment for individuals and corporations, with a substantial number also believing that corporations should be held to a higher standard. Jurors do treat corporations differently, but not for the reasons commonly believed. Jurors don\u27t treat corporations differently because they are overly sympathetic to plaintiffs, or because they have some sort of pre-existing animus against the corporate form or business in society. Rather, it appears that a corporation\u27s size, potential impact, organizational resources, or role responsibility encourage jurors to impose a higher level of responsibility

    A model for hedging load and price risk in the Texas electricity market

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    Energy companies with commitments to meet customers’ daily electricity demands face the problem of hedging load and price risk. We propose a joint model for load and price dynamics, which is motivated by the goal of facilitating optimal hedging decisions, while also intuitively capturing the key features of the electricity market. Driven by three stochastic factors including the load process, our power price model allows for the calculation of closed-form pricing formulas for forwards and some options, products often used for hedging purposes. Making use of these results, we illustrate in a simple example the hedging benefit of these instruments, while also evaluating the performance of the model when fitted to the Texas electricity market

    System for and method of performing evaluation techniques on a log or round timber

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    A system for and method of evaluating a log. The system includes an analysis module having at least one input terminal connectable to the at least one input device. The at least one input terminal is operable to receive at least one signal representing at least one measured property of the log and at least one determined parameter of the log determined in response to an energy being applied to the log. The analysis module further includes a processor coupled to the at least one input terminal. The processor determines a predictive modulus of elasticity (MOE) of the log based at least in part on the at least one measured property and the at least one sensed parameter. The analysis module also includes an output terminal coupled to the processor and connectable to an output device. The output terminal transmits a third signal representing the predictive MOE.https://digitalcommons.mtu.edu/patents/1042/thumbnail.jp
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