排序方式: 共有17条查询结果,搜索用时 0 毫秒
1.
When network demands are uncertain, a planner might design a network based on some nominal set of point‐to‐point demands,
and later be faced with a different set of offered demands. To accommodate the offered demands, modification of the network
may be required. Given this scenario, it seems natural to question how these modification costs might affect the overall cost.
To address such questions, we study the effects of random demands on network costs. In this study, we design a network based
on nominal demands, generate random demands based on the nominal demands, and then modify the designed network to carry the
random demands. We generate the offered demands randomly from four different distributions. For each demand distribution we
perform 300 simulations. This paper describes our observations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
2.
Meyer TE Fox SD Issaq HJ Xu X Chu LW Veenstra TD Hsing AW 《Analytical chemistry》2011,83(14):5735-5740
While sarcosine was recently identified as a potential urine biomarker for prostate cancer, further studies have cast doubt on its utility to diagnose this condition. The inconsistent results may be due to the fact that alanine and sarcosine coelute on an HPLC reversed-phase column and the mass spectrometer cannot differentiate between the two isomers, since the same parent/product ions are generally used to measure them. In this study, we developed a high-throughput liquid chromatography-mass spectrometry (LC-MS) method that resolves sarcosine from alanine isomers, allowing its accurate quantification in human serum and urine. Assay reproducibility was determined using the coefficient of variation (CV) and intraclass correlation coefficient (ICC) in serum aliquots from 10 subjects and urine aliquots from 20 subjects across multiple analytic runs. Paired serum/urine samples from 42 subjects were used to evaluate sarcosine serum/urine correlation. Both urine and serum assays gave high sensitivity (limit of quantitation of 5 ng/mL) and reproducibility (serum assay, intra- and interassay CVs < 3% and ICCs > 99%; urine assay, intra-assay CV = 7.7% and ICC = 98.2% and interassay CV = 12.3% and ICC = 94.2%). In conclusion, this high-throughput LC-MS method is able to resolve sarcosine from α- and β-alanine and is useful for quantifying sarcosine in serum and urine samples. 相似文献
3.
Jalbert Annie; Neath Ian; Bireta Tamra J.; Surprenant Aimée M. 《Canadian Metallurgical Quarterly》2011,37(2):338
The word length effect, the finding that lists of short words are better recalled than lists of long words, has been termed one of the benchmark findings that any theory of immediate memory must account for. Indeed, the effect led directly to the development of working memory and the phonological loop, and it is viewed as the best remaining evidence for time-based decay. However, previous studies investigating this effect have confounded length with orthographic neighborhood size. In the present study, Experiments 1A and 1B revealed typical effects of length when short and long words were equated on all relevant dimensions previously identified in the literature except for neighborhood size. In Experiment 2, consonant–vowel–consonant (CVC) words with a large orthographic neighborhood were better recalled than were CVC words with a small orthographic neighborhood. In Experiments 3 and 4, using two different sets of stimuli, we showed that when short (1-syllable) and long (3-syllable) items were equated for neighborhood size, the word length effect disappeared. Experiment 5 replicated this with spoken recall. We suggest that the word length effect may be better explained by the differences in linguistic and lexical properties of short and long words rather than by length per se. These results add to the growing literature showing problems for theories of memory that include decay offset by rehearsal as a central feature. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
4.
Matthew R Hartings Noah Benjamin Floriene Briere Maria Briscione Omar Choudary Tamra L Fisher Laura Flynn Elizabeth Ghias Michaela Harper Nader Khamis Catherine Koenigsknecht Klare Lazor Steven Moss Elaine Robbins Susan Schultz Samiye Yaman Luke M Haverhals Paul C Trulove Hugh C De Long Abigail E Miller Douglas M Fox 《Science and Technology of Advanced Materials》2013,14(6)
AbstractA technique was developed for preparing a novel material that consists of gold nanoparticles trapped within a fiber of unfolded proteins. These fibers are made in an aqueous solution that contains HAuCl4 and the protein, bovine serum albumin (BSA). By changing the ratio of gold to BSA in solution, two different types of outcomes are observed. At lower gold to BSA ratios (30–120), a purple solution results after heating the mixture at 80 °C for 4 h. At higher gold to BSA ratios (130–170), a clear solution containing purple fibers results after heating the mixture at 80 °C for 4 h. UV–Vis spectroscopy and light scattering techniques show growth in nanocolloid size as gold to BSA ratio rises above 100. Data indicate that, for the higher gold to BSA ratios, the gold is sequestered within the solid material. The material mass, visible by eye, appears to be an aggregation of smaller individual fibers. Scanning electron microscopy and transmission electron microscopy indicate that these fibers are primarily one-dimensional aggregates, which can display some branching, and can be as narrow as 400 nm in size. The likely mechanism for the synthesis of the novel material is discussed. 相似文献
5.
Conflicts involving water resources are pervasive and the costs of the conflicts themselves and attempts to resolve them represent a substantial social investment. Several mechanisms are used to resolve water disputes: litigation, market transactions, political deal-making, and alternative dispute resolution techniques. This article examines the types of costs and benefits associated with resolving water disputes and proposes several criteria to be used in evaluating the economic aspects of dispute resolution mechanisms. 相似文献
6.
Hulme Charles; Suprenant Aimée M.; Bireta Tamra J.; Stuart George; Neath Ian 《Canadian Metallurgical Quarterly》2004,30(1):98
The authors report 2 experiments that compare the recall of long and short words in pure and mixed lists. In pure lists, long words were much more poorly remembered than short words. In mixed lists, this word-length effect was abolished and both the long and short words were recalled as well as short words in pure lists. These findings contradict current models that seek to explain the word-length effect in terms of item-based effects such as difficulty in assembling items, or in terms of list-based accounts of rehearsal speed. An alternative explanation, drawing on ideas of item complexity and item distinctiveness, is proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
This article describes an ongoing project in representing knowledge about Navy tactical computer systems. The primary concern is for their continuing evolution and/or integration with other tactical systems. Following an introduction to this class of application and a review of how the Naval Surface Warfare Center is addressing the issue of extending the investment in these systems, the software process is examined and two alternative, incompatible paradigms are presented. The latter, which relies on the use of software knowledge, is described briefly, and an environment that implements this paradigm is presented as a proof of concept. Because the transfer of this paradigm to the desired Navy applications will not be completed in the near future, the article concludes with the presentation of a general framework for classifying Navy reengineering projects that should improve assessment and also aid in the building of a knowledge base to support the improved process model.Mr. Blum's work was supported in part by the U.S. Navy, Space and Naval Warfare Systems Command (SPAWAR) under contract N00039-89-C-0001, task VMAR9 with the Office of Naval Research (ONR) and the Naval Surface Warfare Center (NAVSWC).Ms. Moore's current affiliation is with the Defense Information Systems Agency, Arlington, VA 22204-2199. The opinions expressed in this paper do not necessarily reflect the views of the Defense Information Systems Agency. 相似文献
8.
Surprenant Aimée M.; Neath Ian; Bireta Tamra J.; Allbritton David W. 《Canadian Metallurgical Quarterly》2008,62(3):141
The acoustic confusion effect is the finding that lists of to-be-remembered items that sound similar to one another are recalled worse than otherwise comparable lists of items that sound different. Previous work has shown that concurrent irrelevant speech and concurrent irrelevant tapping both reduce the size of this effect, suggesting similarities between the two manipulations. The authors assessed the relation between irrelevant speech and irrelevant tapping by correlating the disruption each causes to recall of similar- and dissimilar-sounding items. A significant correlation was obtained, indicating a relation between the two. The results indicate that researchers should be sensitive to changes in the magnitude of the effects rather than focusing exclusively on the presence or absence of particular effects. Implications for the 3 major explanations of the irrelevant speech effect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
目前,南美护肤品销售额占世界市场的8%,达23亿美元。与1993年比,该地区的护肤品销售客增长了128%。一些促销方式的变化、销售途径日趋正常化以及经济政策的变化带来了南美护肤品市场的繁荣。 相似文献
10.
Theoretically appropriate constructs have not been fully established for deviant adult roles. The authors tested (a) whether poor parenting reflects general deviance, (b) whether associations between poor parenting and other adult deviant behaviors could be accounted for by deviant attitudes, and (c) whether these adult roles could be predicted from family support and bonding during adolescence. Data from a community sample of 199 ethnically diverse mothers revealed that Poor Parenting was related to more Polydrug Problems, more Property Crimes, and less Social Conformity. These correlations were accounted for by a higher order factor of General Deviance, although deviant attitudes did not explain the associations among behaviors. Specific correlations delineated associations between types of parenting and deviance. Adolescent family support and bonding reduced mother's Poor Parenting and was unrelated to other adult deviant behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献