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Suppose 1 z1 z2 N, and let [Lambda]i(d) = [mu](d) max(log(zi/d), 0) for i = 1, 2. We show that We then use this to improve a result of Barban-Vehov which has applications to zero-density theorems.
The contractibility number (also known as the Hadwiger number) of a connected graph G, Z(G), is defined as the maximum order of a connected graph onto which G is contractible. An elementary proof is given of a theorem of Ore about this invariant. Also, the extremal problem of finding the maximum Z(G) over all graphs G of a given order and regularity degree is solved.
Commerce in information goods is one of the earliest emerging applications for intelligent agents in commerce. However, the fundamental characteristics of information goods mean that they can and likely will be offered in widely varying configurations. Participating agents will need to deal with uncertainty about both prices and location in multi-dimensional product space. Thus, studying the behavior of learning agents is central to understanding and designing for agent-based information economies. Since uncertainty will exist on both sides of transactions, and interactions between learning agents that are negotiating and transacting with other learning agents may lead to unexpected dynamics, it is important to study two-sided learning. We present a simple but powerful model of an information bundling economy with a single producer an...
Dramatic increases in the capabilities and decreases in the costs of computers and communication networks have fomented revolutionary thoughts in the scholarly publishing community. In one dimension, traditional pricing schemes and product packages are being modified or replaced. We designed and undertook a large-scale field experiment in pricing and bundling for electronic access to scholarly journals: PEAK. We provided Internet-based delivery of content from 1200 Elsevier Science journals to users at multiple campuses and commercial facilities. Our primary research objective was to generate rich empirical evidence on user behavior when faced with various bundling schemes and price structures. In this article we report initial results. We found that although there is a steep initial learning curve, decision-makers rapidly comprehended...
The recent years have witnessed an increasing interest in using wireless structural monitoring as a low-cost alternative to tethered monitoring systems. Previous work considered wireless sensors strictly as passive elements in the monitoring system, responsible only for collection of response measurements. This paper explores expansion of the wireless structural monitoring paradigm by including actuation capabilities in the design of a wireless active sensing unit. To validate the performance of the prototype unit in structural health monitoring applications, an aluminum plate monitored by piezoelectric active sensors is used. Piezoelectric actuators mounted to the surface of the plate are commanded by the wireless active sensing unit to excite and record the element. System identification models are then used to model the linear relat...
A system is conceived of as being slowly varying if it changes slowly enough to permit identification to within a specified error. A generic model is developed to study the identifiability and identification of slowly varying systems. The model is suitable for a large variety of nonlinear, time-varying, causal, bounded memory systems; it has finitely many parameters and is linear in its parameters. Results are obtained with the use of this general model that give guaranteed accuracy of identification as a function of the prior knowledge of the unknown system, the maximum rate of time variation of the system, and the characteristics of output observation noise. To derive these results, a recursive estimation procedure is developed for time-discrete linear dynamical system structures in which the observation noise is statistical but the ...
A morphological mutant of Neurospora crassa, snowflake, is shown to contain filaments which are about 70 A in diameter, and up to several microns long, and which usually bunch in groups of a few to several hundred. They may be found longitudinally or transversely arranged with respect to the long axis of the cell and, in many cases, they run up to the plasma membrane, but not through it. The filaments often are arranged in crystalline arrays but may also be found as separate filaments. Sometimes the filaments are closely appressed to nuclei and may be found inside them. It is likely that the filaments are not the result of the dissociation of microtubules and are most likely microfilaments like those found in other organisms. Their relationship to the origin of certain morphological mutants in Neurospora is discussed.
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