Albert Einstein (front row, third from right) in school group portrait Portraits Groups

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Performance Study of a Centralized Concurrency Control Algorithm for Distributed Database Systems using SIMULA

The stimulation technique has gained much importance in the performance studies of Concurrency Control (CC) algorithms for distributed database systems. However, details regarding the simulation methodology and implementation are seldom mentioned in the literature. One objective of this paper is to elaborate the simulation methodology using SIMULA. Detailed studies have been carried out on a centralised CC algorithm and its modified version. The results compare well with a previously reported study on these algorithms. Here, additional results concerning the update intensiveness of transactions and the degree of conflict are obtained. The degree of conflict is quantitatively measured and it is seen to be a useful performance index. Regression analysis has been carried out on the results, and an optimisation study using the regression model has been performed to minimise the response time. Such a study may prove useful for the design of distributed database systems.

Portrait of the dancing school class of Therese Molling (second row third from right); Germany.

Mille Ottling ran the dancing school. Therese Molling's daughter Liesel (Elizabeth) Gottschalk and brother Hal attended the same school during the mid 1920s

Studio portrait of Gretel Heimann (on right) with her sister Anna Portraits Children

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Henry H. Goldschmidt Gould (seated on right) with unidentified young men and women; Neue Welt Bockbierfest Portraits Groups

Born July 15, 1914, died August 6, 1978

Henry H. Goldschmidt Gould (top row fourth from right) with unidentified school classmates Portraits Children

Born July 15, 1914, died August 6, 1978

Portrait of Gertrud (Trude) Guttmann (on right) with unidentified woman Portraits Groups Women

Born September 8, 1905, worked in a Jewish orphanage in Berlin and was deported to Auschwitz May 17, 1943, where she died.

Erich Gustav Baum (on right) with undientified man (maybe his father-in-law David Dublon?) standing next to a narrow cobblestone street full of horse-drawn carriages Portraits Men

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Herman Sommerfeld (right) in military uniform with an unidentified soldier Portraits Men

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Herman Sommerfeld (fifth from right) with other soldier recruits; Döberitz, Germany Portraits Men

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Portrait of Herman Sommerfeld (right) with two unidentified pilots of the naval air force; Adlershof bei Berlin Portraits Men

Caption reads: Werftbild Abtl Flugzeugmeisterei Adlershof bei Berlin 1917

Young Herbert Strauss (far right) with three unidentified friends walking down a street on an excursion to Sulzfeld, Baden.

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CRC27012 A National Diagnostic Database for Emergency Plant Pests

Development of a national diagnostic database for Emergency Plant Pests which will be web-accessible.