ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Reward revision and the average reward markov decision process (1987)
    Springer
    OR spectrum 9 (1987), S. 203-211 
    Details
    ISSN: 1436-6304
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Zusammenfassung Zur Lösung Markovscher Entscheidungsprozesse (MDP) mit Durchschnitts-Kriterium werden zwei numerische Verfahren, nämlich sukzessive Approximation und modifizierte Politik-Iteration, mit einer Transformation, der sogenannten ‚'Reward-Revision“, kombiniert. Bei dieser Transformation werden die Übergangswahrscheinlichkeiten so abgeändert (ausgedünnt), daß das neue Modell sich numerisch günstiger verhält. Dazu müssen die einstufigen Erträge so revidiert werden, daß die Optimalitäts-Gleichung des neuen Modells im Limes mit der des ursprünglichen übereinstimmt. Numerische Untersuchungen zeigen, daß für MDP mit stark besetzten Übergangsmatrizen, bei denen nur an wenigen Stellen je Zeile große Werte stehen, die Anwendung von ‚'Reward Revision“ zu wesentlichen Einsparungen an Rechenaufwand führen kann.
    Notes: Summary We integrate two numerical procedures for solving the average reward Markov decision process (MDP), standard successive approximations and modified policy iteration with reward revision. Reward revision is the process of revising the reward structure of a second, more computationally desirable MDP so as to produce, in the limit, an optimality equation having a fixed point identical to that associated with the original MDP. A numerical study indicates that for MDP's having a non-sparse transition structure with a small number of relatively large entries per row, the addition of reward revision can have significant computational benefits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01719829
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Factors controlling nitrogen mineralization and nitrification in forest ecosystems in New Mexico (1987)
    Springer
    Biology and fertility of soils 5 (1987), S. 195-202 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen mineralization ; Nitrification ; Organic quality ; New Mexico
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest floor and mineral soil from ponderosa-pine, Douglas-fir, aspen and spruce-fir ecosystems located along a rising gradient in New Mexico were tested with laboratory assays for factors controlling N mineralization and nitrification. We concluded that low pH in combination with factors associated with organic quality controlled N mineralization and almost completely limited nitrification in spruce-fir soils, while N mineralization in the forest floor of ponderosa-pine was limited by low nutrient availability (other than N). Organic quality of the substrate and temporal changes in organic quality appeared to control N-mineralization and nitrification processes in forest-floor and mineral soils from all other sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00256900
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Volatile and water-soluble inhibitors of nitrogen mineralization and nitrification in a ponderosa pine ecosystem (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 97-104 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen mineralization ; Nitrification ; Water-soluble inhibitors ; Allelochemic control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Bioassay experiments were performed to test for inhibition of the processes of nitrogen mineralization and nitrification by organics in the forest floor of a ponderosa pine ecosystem. Water-extractable organics in the forest floor were tested by applying filtered extracts to the assay soil. The extract decreased nitrate production by 17.0% and decreased net mineralization by 4.1%. Inhibition by volatile organics was tested by placing vials containing forest floor or selected terpenoids of ponderosa pine in sealed jars containing the assay soil. Nitrate production was inhibited by 87.4% and 100%, and net nitrogen mineralization was inhibited by 73.3% and 67.7% in the jars with forest floor and terpenoids, respectively. Organics which are partially water-soluble and are volatile (such as terpenoids) would be very effective inhibitors of nitrogen cycling processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257586
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Effects of prescribed fire on rates of decomposition and nitrogen mineralization in a ponderosa pine ecosystem (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 87-95 
    Details
    ISSN: 1432-0789
    Keywords: Fire effects on mineralization ; Ammonification ; Nitrification ; Ponderosa pine soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of a prescribed fire in a ponderosa pine ecosystem on the rates of decomposition and nitrogen mineralization (including ammonification and nitrification) in the forest floor and mineral soil horizons were evaluated. The prescribed fire immediately increased the rates of nitrogen mineralization and nitrification in the forest floor of all burned plots and in the mineral soil of one plot. The rates of decomposition, as measured by CO2 evolution, in both the forest floor and mineral soil were not significantly different immediately after the burn when expressed on an organic matter basis. The rates of nitrogen mineralization in the forest floor and mineral soil were higher 6 and 10 months after the burn. The rate of decomposition (as measured by respiration) was lower in the forest floor but not in the mineral soil 6 and 10 months after the burn. Volatile organics that may inhibit rates of nitrogen mineralization may have been consumed by prescribed fire.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257585
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Seasonal, annual, and treatment-induced variation in available nitrogen pools and nitrogen-cycling processes in soils of two Douglas-fir stands (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 93-99 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium ; Nitrate ; N-mineralization ; Nitrification ; Fertilization ; Irrigation ; Forest ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest-floor and 0–10 cm depth mineral soil horizons in two stands of Douglas fir were sampled for available NH4 +-N and NO3 −-N, N-mineralization potentials, and nitrification potentials for 2 years. The plots in each stand were sampled for 1 year, treated with either ammonium sulfate, carbohydrate (sawdust-sucrose), irrigation, carbohydrate plus irrigation, or no treatment (control), and then sampled for 1 year following treatment. In general, the direction of change following the treatments was the same for both the forest-floor and the mineral soils. Fertilization increased the NH4 +-N and NO3 −-N pools, nitrification potential, and N-mineralization potential, while treatment with carbohydrate decreased all of these characteristics. Irrigation generally increased NH4 +-N pools, nitrification potential, and N-mineralization potential, but decreased these characteristics in the soil at one site. Irrigation plus carbohydrate gave similar results to those of carbohydrate alone. Treatments altered pool sizes and/or potentials, but did not reduce within-year variance in any of these characteristics. Distinct seasonal patterns occurred in all measurements, suggesting that control of short-term variation in N-transformation processes is by factors which are dynamic in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Induced cellular resistance to ultraviolet light in Saccharomyces cerevisiae is not accompanied by increased repair of plasmid DNA (1987)
    Springer
    Current genetics 11 (1987), S. 321-326 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Inducible repair ; Plasmid transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many reports show that resistance of Saccharomyces cerevisiae to a large UV dose can be enhanced by pre-induction with a smaller one given some hours before. This work tests if such increased cell survival is associated with increased DNA repair on UV damaged plasmid transformed into yeast. There was no change in transformation efficiency of UV-damaged plasmid DNA under conditions where RAD cell survival increased 5-fold, and where rad1-1 and rad6-1 survival increased 2-fold. It is concluded that DNA repair activity involving the RAD6 and RAD3 pathways is either not inducible or is unable to work on plasmid DNA. It is suggested that the enhancement of cellular survival detected may be based on changes in cell-cycle behaviour which permit cells generally proficient in repair a greater chance to recover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00355407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ion irradiation effects in nonmetals: formation of nanocrystals and novel microstructures (2000)
    Springer
    Materials research innovations 3 (2000), S. 190-204 
    Details
    ISSN: 1433-075X
    Keywords: Key words Zircon ; Pretulite ; Nanocrystals ; Irradiation ; Semiconductors ; Microstructure ; Nonmetals ; ZnS ; CdS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Ion implantation is a versatile and powerful technique for producing nanocrystal precipitates embedded in the near-surface region of materials. Radiation effects that occur during the implantation process can lead to complex microstructures and particle size distributions, and in the present work, we focus on the application of these effects to produce novel microstructural properties for insulating or semiconducting nanocrystals formed in optical host materials. Nanocrystal precipitates can be produced in two ways: by irradiation of pure (i.e., non-implanted) crystalline or amorphous materials, or by ion implantation followed by either thermal annealing or subsequent additional irradiation. Different methods for the formation of novel structural relationships between embedded nanocrystals and their hosts have been developed, and the results presented here demonstrate the general flexibility of ion implantation and irradiation techniques for producing unique near-surface nanocomposite microstructures in irradiated host materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100190050003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Limits of chemical effects on cold fusion (1990)
    Springer
    Journal of fusion energy 9 (1990), S. 363-366 
    Details
    ISSN: 1572-9591
    Keywords: Palladium-deuterides ; D2 ; clusters ; density-functional calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Cold fusion enhanced by chemical confinement of deuterons has been suggested as an explanation of recent reports of the production of neutrons in electrochemically-generated palladium deuterides. To test this suggestion local-density-functional cluster calculations were used to study the coulomb barrier between two deuterons within the octahedral cage in crystalline palladium. The calculated repulsive forces were always greater than the corresponding forces between deuterons in molecular D2. These results imply that the room temperature fusion rate at this site is negligible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01059258
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Temperature dependence of positron trapping in deformed nickel (1975)
    Springer
    Applied physics 7 (1975), S. 141-143 
    Details
    ISSN: 1432-0630
    Keywords: Positrons ; Defects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Non-equilibrium populations of defects, produced by plastic deformation of Ni, were used to study temperature dependence of the capture cross-section for positrons. A weak positive temperature coefficient was found in material of 99.8% purity but no temperature dependence in 99.99% purity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00884225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Probing interface properties of nanocomposites by third-order nonlinear optics (1996)
    Springer
    Applied physics 62 (1996), S. 403-415 
    Details
    ISSN: 1432-0630
    Keywords: 42.70.Nq ; 42.65.An ; 78.66.Sq
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract We describe the exploitation of third-order nonlinear optical response — particularly nonlinear absorption and the nonlinear index of refraction — to probe interface dynamics, modifications and relaxation processes in granular materials consisting of metal quantum dots embedded in such dielectrics as fused silica and sapphire. Many features of these materials can be interpreted in terms of the quantum-mechanical model of the “particle-in-a-box”. Electronic and thermal relaxation processes in these novel nanocomposites are dominated by interactions of conduction-band electrons at the boundary between the quantum dot and its surrounding host material. Experimental examples presented include measurements of thermal and electronic relaxation rates, dephasing due to electron collisions at the nanocluster surface, effects of local structural order, changes in the saturation parameter due to chemical modification of the substrate, and one-and two-dimensional heat-transfer effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01567111
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...