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171.
Based on a rearrangement inequality by Hardy, Littlewood, and Polya, we define two-operator algebras for independent random variables. These algebras are called Huffman algebras since the Huffman algorithm on these algebras produces an optimal binary tree that minimizes the weighted lengths of leaves. Many examples of such algebras are given. For the case with random weights of the leaves, we prove the optimality of the tree constructed by the power-of-2 rule, i.e., the Huffman algorithm assuming identical weights, when the weights of the leaves are independent and identically distributed. 相似文献
172.
173.
Thomas Emery 《Journal of population ageing》2012,5(1):7-22
The anticipated, dramatic shift in the demographics of European societies over the next half a century begs many questions about the state of relations between generations. Papers and speculations portraying a world in which the elderly rule through parliamentary majorities, preventing reductions in pensions and ??enslaving?? the working population are surprisingly common. Existing literature on these hypotheses focus on the policy preference differences between the young and the old with evidence mixed as to the accuracy of these predictions. This paper aims to build on this debate by looking at the effects that the dependency ratio has on intergenerational relations. By using a multilevel methodology and data from the 2008 European Social Survey, the effect of demographic structure can be observed on the individual level. Yet whilst evidence is found of decreasing legitimacy of welfare for the elderly, this paper argues that this does not point to increasing intergenerational conflict in Europe. 相似文献
174.
K. Srikrishna G. Thomas R. Martinez M. P. Corral S. De Aza J. S. Moya 《Journal of Materials Science》1990,25(1):607-612
The kaolinite-mullite reaction series in single crystal kaolinite has been characterized by transmission electron microscopy. The exotherm observed at 980° C is attributed to the formation of a spinel phase. Mullite crystallites have also been observed with the spinel phase and both phases have a composition near that of 32 mullite. Subsequent heat treatment leads to the growth of mullite crystallites on the original kaolinite plates with the c-axis perpendicular to the plate. 相似文献
175.
176.
Kalinnik Natalia Kiesel Robert Rauber Thomas Richter Marcel Rünger Gudula 《The Journal of supercomputing》2021,77(4):3484-3515
The Journal of Supercomputing - Scientific application codes are often long-running time- and energy-consuming parallel codes, and the tuning of these methods towards the characteristics of a... 相似文献
177.
Requirements Engineering - To reduce program risks, engineering methods capitalizing on modeling and machine assistance have been extensively investigated within systems engineering (and more... 相似文献
178.
Juan Pablo Hourcade Natasha E. Bullock-Rest Thomas E. Hansen 《Personal and Ubiquitous Computing》2012,16(2):157-168
In spite of great improvements in early diagnosis and interventions, most children diagnosed with autism spectrum disorders
(ASD) are unlikely to live independently when they reach adulthood. We have been conducting research on novel computer-based
interventions with the goal of promoting social skills. Working with 26 children with ASD, their teachers, and other stakeholders,
we have iteratively developed a set of activities based on applications that run on multitouch tablets. Our observations suggest
these activities increased pro-social behaviors such as collaboration and coordination, augmented appreciation for social
activities, and provided children with novel forms of expression. 相似文献
179.
Quantitative real-time imaging of myocardium based on ultrasonic integrated backscatter 总被引:5,自引:0,他引:5
Thomas LJ Barzilai B Perez JE Sobel BE Wickline SA Miller JG 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1989,36(4):466-470
The integrated backscatter calculation over the full, two-dimensional echocardiographic sector is implemented to produce images from closed-chest dogs. This new real-time integrated backscatter measurement system allows a continuous determination of integrated backscatter from all myocardial regions in the ultrasonic view. By replacing the conventional video processor in a commercial two-dimensional echocardiographic imager with this new real-time backscatter measurement system, it is possible to produce real-time two-dimensional images based on integrated backscatter. 相似文献
180.
Dickinson CE Campion K Foster AF Newman SJ O'Rourke AM Thomas PG 《Applied ergonomics》1992,23(3):197-201
This paper describes the outcome of user trials of the Nordic Musculoskeletal Questionnaire which encompassed the views of the following groups: data entry clerks, technical staff, administrative clerks and 481 subjects employed in 10 supermarkets. A significant number of improvements was identified, especially concerning its wording, layout and administration. This has led to a standardized version being produced for use in studying the prevalence of reported symptoms in many types of occupational groups. 相似文献