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1.
An accurate printer model that is efficient enough to be used by halftoning algorithms is proposed. The proposed signal processing model (SPM) utilizes a physical model to train adaptive linear combiners (ALCs), after which the average exposure of each subpixel for any input pattern can be calculated using the optimized weight vector. The SPM can be used to model multi-level halftoning and resolution enhancement, as well as traditional halftoning. The SPM is comprised of a single ALC layer followed by a peak-to-average ratio (PAR) correction layer, which serves to produce a PAR of less than 1.5 in the modeled exposure. The PCN (PAR correction network) employs one ALC/pixel and exploits the physics governing the characteristics of exposure in small regions. A relatively small number of training patterns suffices to train the SPM. 相似文献
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JC Posnick MD Wells JM Drake JR Buncic D Armstrong 《Canadian Metallurgical Quarterly》1993,19(5):260-266
Fibrous dysplasia is an abnormal fibroosseous process of bone of unknown cause. The incidence of skull involvement varies, painless enlargement being the most common presenting symptom. Change in vision is a rare but recognized finding. We report a 3-year-old boy with extreme fibrous dysplasia involving the skull base, who presented with blindness. He underwent exposure osteotomies of the frontal bones and orbits to provide access for skull base tumor removal. The orbital roofs were reconstructed with microplate-fixed cranial grafts. One and one half years after tumor excision followed by immediate reconstruction, the boy retains facial symmetry, and his ocular function has not deteriorated. 相似文献
4.
We have shown that normal and human papillomavirus (HPV) type 16 immortalized human foreskin keratinocytes are growth inhibited by tumor necrosis factor alpha (TNF-alpha), whereas HPV-18- and SV40-immortalized keratinocytes are resistant to this cytokine (1). In this report, we investigated the expression of mitotic regulatory proteins, such as cyclin A, cyclin B, and p34cdc2. After exposure to TNF-alpha, normal and HPV-16-immortalized cells exhibited a dramatic decrease in the expression of these proteins. In contrast, no alteration in the levels of these proteins was observed after treatment of the resistant cell lines, as well as two HPV-positive cervical carcinoma cell lines. Expression of cyclin E does not seem to be modulated by TNF-alpha in any of the cells tested. On the other hand, cyclin D1, expression is slightly increased in normal keratinocytes and in the HPV-16-immortalized cells, whereas no alteration was observed in the HPV-18-transfected cells. The phosphorylation state of pRb correlated with cell growth; sensitive cells, which accumulate in G0-G1, after exposure to TNF-alpha, exhibited an accumulation of hypophosphorylated pRb, whereas no effect on pRb phosphorylation was observed for HPV-18-immortalized cells. These results clearly correlate with TNF-alpha-induced growth arrest in G0-G1. 相似文献
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Continuous simulation is performed using the US Environmental Protection Agency (USEPA) Storm Water Management Model (SWMM) to evaluate regional differences around the United States in hydrologic and water quality performance of wet-weather controls. Controls are characterised as being limited by peak inflow rate (i.e. any device with little or no storage, such as screens, filters and some proprietary devices) or by storage capacity (e.g., ponds, tanks). For flow-limited devices, results are presented in the form of percentage of annual runoff volume captured (passing through the device) for a given inflow capacity. For storage-limited devices, results are presented in two forms: percentage of annual runoff volume captured as a function of unit basin size and drawdown (drain) time, and as a percentage of total suspended solids captured, for the same two variables. Regional differences are apparent, driven mainly by variations in rainfall patterns around the country. 相似文献
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The Magtalo prototype environment harnesses dialogue protocols to support flexible, intuitive interaction with data in complex, contentious domains and provides mechanisms for eliciting structured knowledge. Magtalo represents the first example of an implemented online system that uses a closely specified argument-based dialogue protocol combined with a rich language for representing monologic argument to provide a tool for intuitive user exploration of a disagreement space. This approach also enables the expansion of argument resources through knowledge elicitation, which is structured by the argument dialogue protocol. The continuing aim of our research is to use advances in argumentation theory to push the practice of argumentation technology in providing tools and interfaces that have wide appeal. 相似文献
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Cytomegalovirus (CMV) is the leading cause of congenital viral infection in the United States. To prevent damaging congenital CMV infections, it is necessary to have accurate population estimates of prevalence and to identify maternal factors associated with an elevated risk of congenital infection in the newborn. From 1980 through 1990, 17,163 offspring of predominantly low-income nonwhite women who delivered at a public hospital and 9892 newborns of predominantly mid- to upper-income white women who delivered at a private hospital were screened for congenital CMV infection. Women < 20 years old (adjusted prevalence odds ratio [POR], 4.8; 95% confidence interval [CI], 2.6-8.9) at the public hospital and all nonwhite women (adjusted POR, 1.6; 95% CI, 1.1-2.2) had an increased risk of delivering an infected newborn. Newborns of adolescent women in both populations had the highest prevalence of clinically apparent infection. Offspring of nonwhite low-income adolescents are at greatest risk for congenital CMV infection and more damaging sequelae. 相似文献
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In this study a representative sample of German acute care hospitals is used to describe the effects of dementia within acute care hospitals. Data from hospital patients above age 60 with the diagnosis dementia (ICD 290, 293, 294 and 310), collected over an observation period of 12 years, are compared with nondemented hospital patients at the same ages. The differences in the average length of stay between demented and nondemented patients are only relatively small in German acute care hospitals. The degree of multimorbidity is higher and hospital infections are more frequent for demented patients. The main differences occur with mortality: demented inpatients of both sexes experience a hospital mortality which is about twice as high as for nondemented patients at the same ages. 相似文献
10.
H Lee KB Idler P Swanson JJ Aparicio KK Chin JP Lax M Nguyen T Mann G Leckie A Zanetti 《Canadian Metallurgical Quarterly》1993,196(1):57-69
Seven cardiac electrophysiology stimulators from four manufacturers (Biotronik, Bloom, Digitimer and Medtronic) in common current use are reviewed. The stimulators differ in the features provided and the design adopted to achieve these features. The number of output channels ranges from one to four, the number of extra-stimuli available ranges from two to six, and these can be delivered as a variety of sequences. Some of the stimulators (Digitimer and Bloom) are modular while others (Biotronik and Medtronic 532 series) are of an integrated design comprising a single physical unit. The design of the Medtronic EP-2 has both integrated and modular characteristics. The features of the stimulators associated with input, output, control and the user interface are specifically reviewed. The features are also compared against the published recommendations of the American Heart Association. In addition, a summary of stimulator user comments from a number of electrophysiology centres is presented. All of the stimulators fulfil, or are close to fulfilling, basic electrophysiological requirements, but some provide more complex facilities such as would be required by specialist centres. 相似文献