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  • 1
    Electronic Resource
    Electronic Resource
    Fuzzy Retrieval in fallbasierten entscheidungsunterstützenden Systemen (1998)
    Springer
    OR spectrum 20 (1998), S. 189-198 
    Details
    ISSN: 1436-6304
    Keywords: SchlüsselwörterFuzzy Retrieval – Lineare Boolesche Optimierung – Entscheidungsunterstützende Systeme – Angebotssysteme ; Key words: Fuzzy retrieval – Linear Boolean optimization – Decision support systems – Sales systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Abstract. This paper describes a technique which determines suitable product offers from data bases using the theory of fuzzy sets. Each of the decision criteria is assessed by the customer. His preferences are transformed into membership functions. One gets a suitable offer by maximizing a function which results from the composition of the individual membership functions. We propose the Werners operator for this composition because – it permits the search for a suitable offer to be performed by solving a linear Boolean optimization task and – it reacts more sensitively to customer wishes than the minimum operator. This approach is also feasible for solely verbal criteria and data bases of bigger size.
    Notes: Zusammenfassung In der Arbeit wird gezeigt, wie mit Hilfe der Theorie der unscharfen Mengen geeignete Angebote aus Datenbanken bestimmt werden können. Zur Berechnung wird jedes der einzelnen Entscheidungskriterien durch den Kunden eingeschätzt. Seine Präferenzen werden in Zugehörigkeitsfunktionen umgesetzt. Ein geeignetes Angebot erhält man nun durch Maximierung einer Funktion, die sich als Komposition der einzelnen Zugehörigkeitsfunktionen ergibt. Für diese Verknüpfung schlagen wir den Werners-Operator vor, da er – die Suche nach einem geeigneten Angebot durch Lösung einer linearen Booleschen Optimierungsaufgabe zuläßt und – sensitiver auf die Kundenwünsche reagiert als der Minimumoperator. Dieser Zugang ist auch möglich bei nur verbal formulierbaren Kriterien und größeren Datenbanken.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002910050067
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Fuzzy Retrieval in fallbasierten entscheidungsunterstützenden Systemen (1998)
    Springer
    OR spectrum 20 (1998), S. 189-198 
    Details
    ISSN: 1436-6304
    Keywords: Fuzzy Retrieval ; Lineare Boolesche Optimierung ; Entscheidungsunterstützende Systeme ; Angebotssysteme ; Fuzzy retrieval ; Linear Boolean optimization ; Decision support systems ; Sales systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Abstract This paper describes a technique which determines suitable product offers from data bases using the theory of fuzzy sets. Each of the decision criteria is assessed by the customer. His preferences are transformed into membership functions. One gets a suitable offer by maximizing a function which results from the composition of the individual membership functions. We propose the Werners operator for this composition because it permits the search for a suitable offer to be performed by solving a linear Boolean optimization task and it reacts more sensitively to customer wishes than the minimum operator. This approach is also feasible for solely verbal criteria and data bases of bigger size.
    Notes: Zusammenfassung In der Arbeit wird gezeigt, wie mit Hilfe der Theorie der unscharfen Mengen geeignete Angebote aus Datenbanken bestimmt werden können. Zur Berechnung wird jedes der einzelnen Entscheidungskriterien durch den Kunden eingeschätzt. Seine Präferenzen werden in Zugehörigkeitsfunktionen umgesetzt. Ein geeignetes Angebot erhält man nun durch Maximierung einer Funktion, die sich als Komposition der einzelnen Zugehörigkeitsfunktionen ergibt. Für diese Verknüpfung schlagen wir den Werners-Operator vor, da er die Suche nach einem geeigneten Angebot durch Lösung einer linearen Booleschen Optimierungsaufgabe zuläßt und sensitiver auf die Kundenwünsche reagiert als der Minimumoperator. Dieser Zugang ist auch möglich bei nur verbal formulierbaren Kriterien und größeren Datenbanken.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539769
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Chronic effects of low insecticide concentrations on freshwater caddisfly larvae (1995)
    Springer
    Hydrobiologia 299 (1995), S. 103-113 
    Details
    ISSN: 1573-5117
    Keywords: chronic toxicity ; emergence ; low-level pollution ; lindane ; parathion ; Trichoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The insecticide load in surface waters does not ordinarily reach concentrations acutely toxic to aquatic fauna. The effects of the low insecticide concentrations typical of natural habitats are still not clear, for they often appear only after relatively long exposure times. To test such a situation, the insecticides lindane and parathion were introduced into a static-with-renewal outdoor aquaria system at concentrations about four and five orders of magnitude lower than their respective 96-h LC50s, and their chronic (about 90 days) effects on the survival rate of freshwater caddisfly larvae were observed. The emergence and hence survival rate of Limnephilus lunatus Curtis was significantly reduced by lindane at 0.1 ng l−1, a value nearly five orders of magnitude lower than the 96-h LC50. Parathion, with acute and subacute toxicity similar to that of lindane, did not significantly alter the emergence rate of this species. In contrast, this substance did produce a significant reduction in emergence rate of the closely related species Limnephilus bipunctatus Curtis at 1 ng l−1, even though this species was significantly less susceptible than L. lunatus to parathion at high concentrations. We conclude that chronic insecticide exposure can be hazardous to freshwater macroinvertebrates even at unexpectedly low concentrations. The low-concentration effects may depend on both species and substance and therefore cannot be predicted from toxicity data at higher concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017562
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Chronic effects of short-term contamination with the pyrethroid insecticide fenvalerate on the caddisfly Limnephilus lunatus (1996)
    Springer
    Hydrobiologia 324 (1996), S. 99-106 
    Details
    ISSN: 1573-5117
    Keywords: chronic toxicity ; sublethal effects ; low-level pollution ; short-term contamination ; emergence ; pyrethroid ; Trichoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Larvae of the caddisfly Limnephilus lunatus Curtis were exposed to the pyrethroid fenvalerate for one hour and transferred to artificial outdoor stream systems, where their survival rate and emergence were monitored over 84 days. Lethal effects of the pyrethroid almost always appeared shortly after the short-term contamination, but chronic influences were also observed. At a concentration of only 0.01 µg l−1 a slight increase in mortality over the entire period of observation, as well as a delay in development and hence in emergence occurred. Such reactions under field conditions may impair the survival of this species, and sublethal effects of brief pyrethroid contamination, previously largely ignored, can have important consequences for aquatic macroinvertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018170
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    Paper (German National Licenses)
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  • 5
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    As above, so below? Effects of fungicides on microbial organic matter decomposition are stronger in the hyporheic than in the benthic zone (2021)
    John Wiley & Sons, Inc. | Hoboken, USA
    Details
    Publication Date: 2022-04-04
    Description: Microbial organic matter decomposition is a critical ecosystem function, which can be negatively affected by chemicals. Although the majority of organic matter is stored in sediments, the impact of chemicals has exclusively been studied in benthic systems. To address this knowledge gap, we assessed the impact of a fungicide mixture at three concentrations on the decomposition of black alder leaves in the benthic and hyporheic zone. We targeted two sediment treatments characterized by fine and coarse grain sizes (1–2 vs. 2–4 mm). Besides microbial communities' functioning (i.e., decomposition), we determined their structure through microbial biomass estimates and community composition. In absence of fungicides, leaf decomposition, microbial biomass estimates and fungal sporulation were lower in the hyporheic zone, while the importance of bacteria was elevated. Leaf decomposition was reduced (40%) under fungicide exposure in fine sediment with an effect size more than twice as high as in the benthic zone (15%). These differences are likely triggered by the lower hydraulic conductivity in the hyporheic zone influencing microbial dispersal as well as oxygen and nutrient fluxes. Since insights from the benthic zone are not easily transferable, these results indicate that the hyporheic zone requires a higher recognition with regard to ecotoxicological effects on organic matter decomposition.
    Description: German Research Foundation, Project AQUA‐REG http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:550.724 ; ddc:579
    Language: English
    Type: doc-type:article
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