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121.
Harald Hruschka 《OR Spectrum》2007,29(4):579-595
Clusterwise pricing is characterized by prices of each brand of a category being equal in stores belonging to the same cluster.
Expected sales necessary to compute profits are estimated using coefficients of a multilayer perceptron which performs better
than several parametric models. Store-specific coefficients of sales response models are estimated by a MCMC method. Both
assignment of stores to clusters and prices of each cluster are determined by means of improving hit-and-run, a stochastic
optimization method. The objective function to be optimized includes both profits and adherence to the usual price level at
individual stores. Based on empirical data on sales, prices and marginal costs of a retail chain it is demonstrated that for
a moderate level of risk aversion clusterwise pricing leads to higher expected utility than micromarketing pricing with different
prices of each brand across individual stores. Clusterwise pricing attains a high percentage of the profits generated by micromarketing
pricing and entails lower menu costs than micromarketing pricing.
H. Hruschka thanks two anonymous reviewers for their interest and their detailed helpful comments. 相似文献
122.
Erik Benkler Andreas G. Steffan Harald R. Telle 《Photonics Technology Letters, IEEE》2007,19(5):267-269
We demonstrate a novel synchronization scheme for optical sampling which is based on a nonstandard phase-locked loop (PLL). Phase comparison is performed at a 10-GHz optical time-division-multiplexing (OTDM) base rate, thus avoiding ultrafast detectors and electronics. The employed frequency-offset PLL allows synchronous sampling of OTDM signals (or any other signals with bit rates given by integer multiples of the base rate), which would be impossible using a standard PLL. This provides a higher degree of flexibility for problem-specific sweeping than asynchronous sampling 相似文献
123.
Juan M. Carrillo Miguel A. Montecelo Harald Neubauer Hans Hauer J. Francisco Duque-Carrillo 《Analog Integrated Circuits and Signal Processing》2007,53(2-3):63-69
This paper deals with the implementation of a second-order ΣΔ modulator in 0.18-μm CMOS technology. The analog-to-digital converter structure combines a 1-bit approach along with a high oversampling ratio (OSR). A silicon circuit prototype, including the modulator itself, a current reference, and the clock signals generator, was designed to operate with a 1.8-V supply, fabricated and tested. Measured values of 87 dB and 91 dB were obtained for the signal-to-noise-plus-distortion ratio (SNDR) and the dynamic range (DR), respectively, for a clock frequency of 8 MHz and an OSR of 256. The effective number of bits (ENOB) was above 14. The experimental performance of the ΣΔ modulator maintains a good level over a modulator clock range higher than 16 MHz, featuring an ENOB equal to 13 at 16 MHz. 相似文献
124.
125.
By varying cross-linking intensity, the effect of microbial transglutaminase on acid gels made from casein solution and raw milk was studied. To avoid any impact of heating, N-ethylmaleimide was used for enzyme inactivation after appropriately checking its efficiency. Up to a specific degree of oligomerisation gel stiffness and firmness increased and tan δ, time at gelation onset and syneresis decreased. Above approximately 70% and 25% of cross-linked protein in casein solution and raw milk, respectively, these parameters showed an opposite behaviour, and weak gels with high syneresis were obtained. Substrate differences, such as preferred cross-linking of adjoining κ-caseins on the surface of the micelle enhanced the effect of steric hindrance in raw milk and impaired proper rearrangements upon acidification at a much lower level of oligomerised protein. It is mainly dimeric and trimeric casein that successfully contributed to the enhanced properties of milk protein gels. 相似文献
126.
The refractory lining in steel ladles is exposed to chemical and mechanical loads during the heats. Mechanical loads develop from the thermal expansion of the refractories which is confined either by the steel construction or by regions of different temperature within the refractory material. The aim of this work was the investigation of factors influencing the mechanical durability of refractory steel ladle linings and the clarification of failure mechanisms. Especially irreversible strains at the hot face of the working lining caused by compressive stresses induce an opening of joints at the hot face. The irreversible strains reduce the compressive stresses in circumferential direction and increase the probability of tensile failure. A further effect of the irreversible strains is a reduced stability of the working lining. Of special interest in this context is a possible controlled expansion of bricks to counterbalance the irreversible compressive strains. 相似文献
127.
Burhan Muhsin Joachim Renz K.-H. Drüe Gerhard Gobsch Harald Hoppe 《Synthetic Metals》2009,159(21-22):2358-2361
Polymer solar cell modules based on the standard polymer–fullerene system of to-date, P3HT–PCBM, have been prepared and characterized. We have observed a loss of only 20% when up-scaling the active area of the solar cell by a factor somewhat larger than 10. An average solar cell efficiency of 3% and a module efficiency of 1.9% for three serially interconnected solar cells of 5.4 cm2 each are reported. The route for further optimization of module performance is discussed based on analyzing the existing loss factors within this design. 相似文献
128.
Hannay Jo E. Arisholm Erik Engvik Harald Sjoberg Dag I.K. 《IEEE transactions on pattern analysis and machine intelligence》2010,36(1):61-80
Personality tests in various guises are commonly used in recruitment and career counseling industries. Such tests have also been considered as instruments for predicting the job performance of software professionals both individually and in teams. However, research suggests that other human-related factors such as motivation, general mental ability, expertise, and task complexity also affect the performance in general. This paper reports on a study of the impact of the Big Five personality traits on the performance of pair programmers together with the impact of expertise and task complexity. The study involved 196 software professionals in three countries forming 98 pairs. The analysis consisted of a confirmatory part and an exploratory part. The results show that: 1) Our data do not confirm a meta-analysis-based model of the impact of certain personality traits on performance and 2) personality traits, in general, have modest predictive value on pair programming performance compared with expertise, task complexity, and country. We conclude that more effort should be spent on investigating other performance-related predictors such as expertise, and task complexity, as well as other promising predictors, such as programming skill and learning. We also conclude that effort should be spent on elaborating on the effects of personality on various measures of collaboration, which, in turn, may be used to predict and influence performance. Insights into such malleable, rather than static, factors may then be used to improve pair programming performance. 相似文献
129.
130.
Ausgangspunkt unserer Untersuchungen zur Conjointanalyse-basierten wettbewerbsorientierten Produktgestaltung bilden segmentspezifische konditionale MNL-Modelle. Bisher auf diesem Gebiet entwickelte Ans?tze, die sich mit der Bestimmung von Marktgleichgewichten befassen, beschr?nken sich ausschlie?lich auf den Single-Produkt-Fall (z.B. Choi u. DeSarbo, 1993; Green u. Krieger, 1997). Unser Beitrag setzt sich ebenfalls mit dem Single-Produkt-Fall (d.h. ein Produkt je Anbieter) auseinander, behandelt darüber hinaus erstmals aber auch den Wettbewerb mit Produktlinien. Gegenstand der Untersuchungen sind insbesondere die Existenz und Eindeutigkeit simultaner Positions-Preis- Gleichgewichte, die Existenz ineffizienter Marktgleichgewichte sowie der Differenzierungsgrad zwischen Konkurrenzprodukten. 相似文献