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1.
The structure of the nonlinear H∞-filter in the neighborhood of the estimated trajectory is investigated and a bound on the size of the neighborhood that allows this structure is determined, both for finite and infinite horizons. Riccati inequalities that depend on the estimated trajectory are derived for finding the filter gain matrix and an algorithm for calculating the bound on the size of the above neighborhood is presented. Explicit formulas are obtained in the infinite horizon case for the minimum achievable disturbance attenuation level, the size of the neighborhood, and the corresponding filter gain. 相似文献
2.
Noel D. Uri 《Applied Energy》1996,54(4):355-373
This study begins by asking whether fluctuations in the price of crude oil have affected agricultural employment in the USA. After reviewing previous assessments of the issue, the existence of an empirical relationship between agricultural employment and crude-oil price volatility is established using Granger causality. Subsequently, the nature of the relationship is estimated with the results suggesting that at least three full years are required before the measurable impacts of a percentage change in the real price of crude oil on the change in agricultural employment are exhausted. Finally, the structural stability of the functional relationship between the change in agricultural employment and the volatility of the price of crude oil, the percentage changes in expected net farm income, realized technological innovation, and the wage rate are examined. 相似文献
3.
We consider two multicriteria versions of the global minimum cut problem in undirected graphs. In the k-criteria setting,
each edge of the input graph has k non-negative costs associated with it. These costs are measured in separate, non-interchangeable,
units. In the AND-version of the problem, purchasing an edge requires the payment of all the k costs associated with it. In the OR-version, an edge can be purchased by paying any one of the k costs associated with it. Given k bounds b1,b2,. . . ,bk, the basic multicriteria decision problem is whether there exists a cut C of the graph that can be purchased using a budget
of bi units of the ith criterion, for 1 ≤ i ≤ k. We show that the AND-version of the multicriteria global minimum cut problem is
polynomial for any fixed number k of criteria. The OR-version of the problem, on the other hand, is NP-hard even for k = 2,
but can be solved in pseudo-polynomial time for any fixed number k of criteria. It also admits an FPTAS. Further extensions,
some applications, and multicriteria versions of two other optimization problems are also discussed. 相似文献
4.
Uri Zwick 《Algorithmica》2006,46(2):181-192
We present an
-time algorithm for the All Pairs Shortest Paths (APSP) problem for directed graphs with real edge lengths. This slightly
improves previous algorithms for the problem obtained by Fredman, Dobosiewicz, Han, and Takaoka. 相似文献
5.
A theory is developed for the construction of carry-save networks with minimal delay, using a given collection of carry-save adders each of which may receive inputs and produce outputs using several different representation standards.The construction of some new carry-save adders is described. Using these carry-save adders optimally, as prescribed by the above theory, we get {, , }-circuits of depth 3.48 log2
n and {, , }-circuits of depth 4.95 log2
n for the carry-save addition ofn numbers of arbitrary length. As a consequence we get multiplication circuits of the same depth. These circuits put out two numbers whose sum is the result of the multiplication. If a single output number is required then the depth of the multiplication circuits increases respectively to 4.48 log2
n and 5.95 log2
n.We also get {, , }-formulae of sizeO (n
3.13) and {, }-formulae of sizeO (n
4.57) for all the output bits of a carry-save addition ofn numbers. As a consequence we get formulae of the same size for the majority function and many other symmetric Boolean functions. 相似文献
6.
Uri Cohen 《Journal of Electronic Materials》1977,6(6):607-643
Electrodeposition of both epitaxial and polycrystalline continuous films of dense, coherent, and well-adherent silicon coatings
was achieved from molten fluorides. A dissolving Si anode and an operating temperature of about 750 C were utilized. Silicon
electrocrystallization epitaxy (ECE) produced films with the (111) orientation on Si substrates of the same orientation. The
unintentionally doped films were of p-type character with a resistivity in the range 0.05 - 0.10 Ω-cm. Polycrystalline Si
films were similarly electroplated onto various polycrystalline metal substrates. Uniform coherent, and well-adherent coatings
with grain diameters as large as 40 – 50 μm were obtained. The useful rate of electrodeposition of Si could be significantly
increased by the application of an alternating square wave pulse (ASWP)2technique. Cathodic current pulses as high as 300 mA/cm2 (growth rate of about 5 μm/min) were demonstrated. The cathodic current efficiencies, for all modes of growth, were about
70 – 100%. The effects of the various operating parameters, and some prospective applications to the fabrication of solar
cells, are discussed.
This was paper A-6 in the 18th Annual Electronic Materials Conference, Salt Lake City, June 23–25, 1976. 相似文献
7.
Market power and the deregulation of special access service by the Federal Communications Commission
In 1999, the Federal Communications Commission adopted an order granting complete deregulation of the rates for special access service for specific metropolitan statistical areas based on an objective showing that there was potential competition in that market. This was done in an environment where the local exchange carriers (LECs) subject to price caps were earning a rate of return in excess of 22% with the rate of return on an upward trend. By 2002, the average rate of return across all price cap LECs topped 35%. The questions investigated in this article are whether the price cap LECs have market power in supplying special access service and whether they have taken advantage of this. The data clearly show that this is the case. Given the prevailing situation, there is a clear need to revisit the pricing flexibility order. First, the product market for special access service needs to be more carefully examined and, second, the metrics used to define the potential for competition need to be revamped. 相似文献
8.
The application and development of biopolymer-based particulate delivery systems is receiving considerable attention from scientists and manufacturers seeking to engineer healthier and safer foods. Present work focused on the fabrication and proteolysis of bovine lactoferrin nano-particles onto which pectins, alginate and carrageenan were electrostatically deposited. DLS, CD and AFM were used to ascertain the formation of spherical structures with varying zeta potentials and modified protein folding. SDS-PAGE analyses of samples collected during simulated human gastro-duodenal digestion revealed that in the case of high and low methoxy pectin particle zeta potential values (−35.4 mV and −50.3 mV respectively) were found to be inversely linked to lactoferrin digestion rate. Moreover, the electrostatic binding of food grade iota-carrageenan onto lactoferrin nano-particles was found to yield highly charged particles (zeta = −69.2 mV) with low surface roughness and to enable a proportion of the lactoferrin to resist 1 h of simulated gastric digestion. Overall, these findings suggest that electrostatic biopolymer interactions may modulate protein digestion and possibly facilitate controlled protein delivery to the upper gastrointestinal tract or have implications to protein nutritional value. 相似文献
9.
Model demonstrating the potential for coupled nitrification denitrification in soil aggregates 总被引:2,自引:0,他引:2
A model of reactive, multi-species diffusion has been developed to describe N transformations in spherical soil aggregates, emphasizing the effects of irrigation with reclaimed wastewater. Oxygen demand for respiratory activity has been shown to promote the establishment of anaerobic conditions. Aggregate size and soil respiration rate were identified as the most significant parameters governing the existence and extent of the anaerobic volume in aggregates. The inclusion of kinetic models describing mineralization, nitrification, and denitrification facilitated the investigation of coupled nitrification/denitrification (CND), subject to O2 availability. N-transformations are shown to be affected by effluent-borne NH4+-N content, in addition to elevated BOD and pH levels. Their incremental contribution to O2 availability has been found to be secondary to respiratory activity. At the aggregate level, significant differences between apparent and gross rates of N-transformations were predicted (e.g., NH4+ oxidation and N2 formation), resulting from diffusive constraints due to aggregate size. With increasing anaerobic volume, the effective nitrification rate determined at the aggregates level decreases until its contribution to nitrification is negligible. It was found that the nitrification process was predominantly limited to aggregates <0.25 cm. Assuming that nitrification is the main source for NO3- formation, denitrification efficiency is predicted to peak in medium-sized aggregates, where aerobic and anaerobic conditions coexist, supporting CND. In effluent-irrigated soils, the predicted NO2- formation rate in small aggregates is enhanced when compared to freshwater-irrigated soils. The difference vanishes with increasing aggregate size as anaerobic NO2- consumption exceeds aerobic NO2- formation due to the coupling of nitrification and denitrification. 相似文献
10.
Sigal Meirovitch Zvi Shtein Tal Ben-Shalom Shaul Lapidot Carmen Tamburu Xiao Hu Jonathan A. Kluge Uri Raviv David L. Kaplan Oded Shoseyov 《International journal of molecular sciences》2016,17(9)
The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites. 相似文献