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排序方式: 共有2105条查询结果,搜索用时 31 毫秒
51.
Visualization of heterogeneous data 总被引:1,自引:0,他引:1
52.
My early research was inspired by the mathematical semantics of Scott and Strachey. Two such topics, recounted in this paper, were the fixed-point analysis of pointer loops and the expressibility of a style of functional programming introduced by Barron and Strachey. 相似文献
53.
In an attempt to ascertain the value of extra- to intracranial arterial bypass for cerebrovascular disease, the general topic of bypass surgery is reviewed and the results of this procedure in 110 patients are analyzed. The feasibility of high patency rates of the anastomosis with acceptably low permanent morbidity and operative mortality rates is demonstrated. Lesions producing transient ischemic attacks which previously were considered to be inoperable or inaccessible can be bypassed by this procedure, and there appears to be a dramatic improvement in the symptomotology of virtually all patients. Patients with a mild stroke or "progressive stroke" also appear to benefit from bypass, but the erratic natural history of these entities precludes irrefutable substantiation of this conclusion. Patients with moderate-to-serve neurological deficits do not appear to be improved by this procedure. In our group of 20 patients presenting with transient ischemic attacks who have had more than 3 years of follow-up, only one patient has suffered a stroke and that was located in the opposite hemisphere. 相似文献
54.
Mike Livesey 《International journal of parallel programming》1991,20(1):55-74
We consider two algorithms for the barrier synchronization ofN processes: the Dissemination algorithm(2) and Brooks algorithm.(1,2) Both algorithms comprise a number of binary communications amongst the processes, organized into a sequence of stages. It is shown that Brooks' algorithm(1) requires between LogN(log2
N) and 2 LogN stages, the lower bound being guaranteed only in the case thatN is a power of 2 (cubic) and the upper bound seemingly needed for most otherN. On the other hand, it is shown(2) that the Dissemination algorithm requires only LogN stages regardless ofN, making it apparently superior to the Brooks algorithm. We introduce a network model of local barrier algorithms. Using it we obtain a rigorous correctness proof for local barrier algorithms, and show that the number of stages in the Brooks algorithm is bounded above by LogN+1. The Brooks algorithms is therefore essentially equivalent in time complexity to the Dissemination algorithm. We then address the question of which values ofN admit exactly LogN Brooks stages. We find a sufficient condition, and conjecture that it is also necessary. 相似文献
55.
Christian Bur Peter Reimann Mike Andersson Anita Lloyd Spetz Andreas Schütze 《Microsystem Technologies》2012,18(7-8):1015-1025
A silicon carbide based enhancement type metal insulator field effect transistor with porous gate metallization has been investigated as a total NO x sensor operated in a temperature cycling mode. This operating mode is quite new for gas sensors based on the field effect but promising results have been reported earlier. Based on static investigations we have developed a suitable T-cycle optimized for NO x detection and quantification in a mixture of typical exhaust gases (CO, C2H4, and NH3). Significant features describing the shape of the sensor response have been extracted and evaluated with multivariate statistics (e.g. linear discriminant analysis) allowing quantification of NO x . Additional cleaning-cycles every 30?min improve the stability of the sensor further. With this kind of advanced signal processing the influence of sensor drift and cross sensitivity to ambient gases can be reduced effectively. Measurements have proven that different concentrations of NO x can be detected even in a changing mixture of other typical exhaust gases under dry and humid conditions. In addition to that, unknown concentrations of NO x can be detected based on a small set of training data. It can be concluded that the performance of GasFETs for NO x determination can be enhanced considerably with temperature cycling and appropriate signal processing. 相似文献
56.
Haixue Yan Hongtao Zhang Rick Ubic Mike Reece Jing Liu Zhijian Shen 《Journal of Materials Science: Materials in Electronics》2006,17(9):657-661
Grain-oriented Aurivillius phase BaBi2Nb2 O9 ceramics were fabricated using Spark Plasma Sintering (SPS). Their relaxor behaviour was confirmed by a strong frequency
dispersion of the dielectric response. The dielectric behaviour has been fitted using different relaxor models. The relaxor
parameters are isotropic, while the dielectric constants are highly anisotropic. The piezoelectric constant d
33 is zero perpendicular and parallel to the hot pressing direction, and the P–E response is dominated by losses. The inability to pole the samples at room temperature is consistent with the T
f temperature (∼
∼115 K) estimated from fitting the experimental data to the Vogel–Fulcher model. This suggests that it may be possible to
observe piezoelectric and ferroelectric properties at very low temperatures. 相似文献
57.
Halari Rozmin; Hines Melissa; Kumari Veena; Mehrotra Ravi; Wheeler Mike; Ng Virginia; Sharma Tonmoy 《Canadian Metallurgical Quarterly》2005,119(1):104
Sexually dimorphic cognitive performance in men (n=42) and women (n=42) was related to testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin, measured in 10-ml blood samples collected between 0900 and 1030 and, among women, during the follicular phase of the menstrual cycle. Significant sex differences favored men on spatial tasks (Mental Rotation and Judgment of Line Orientation) and on an inhibition task and favored women on a verbal task (category fluency). However, there were no significant relationships between any of the hormones and cognitive performance, suggesting that there are few, if any, consistent, substantial relationships between endogenous, nonfluctuating levels of gonadal hormones or gonadotropins and these cognitive abilities in men or women. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
Lutz Wolfgang; Leach Chris; Barkham Michael; Lucock Mike; Stiles William B.; Evans Chris; Noble Rachael; Iveson Steve 《Canadian Metallurgical Quarterly》2005,73(5):904
This study extended client-focused research by using the nearest neighbor (NN) approach, a client-specific sampling and prediction strategy derived from research on alpine avalanches. Psychotherapy clients (N = 203) seen in routine practice settings in the United Kingdom completed a battery of intake measures and then completed symptom intensity ratings before each session. Forecasts of each client's rate of change and session-by-session variability were computed on the basis of that client's NNs (n = 10-50 in different comparisons). Alternative forecasts used linear or log-linear slopes and were compared with an alternative prediction strategy. Results showed that the NN approach was superior to the alternative model in predicting rate of change, though the advantage was less clear for predicting variability. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Although many link patterns have been identified at the university level, departmental interlinking has been relatively ignored.
Universities are multidisciplinary by nature and various disciplines may employ the Web differently, thus patterns identified
at the university level may hide subject differences. Departments are typically subject-oriented, and departmental interlinking
may therefore illustrate interesting disciplinary linking patterns, perhaps relating to informal scholarly communication.
The aim of this paper is to identify whether and how link patterns differ along country and disciplinary lines between similar
disciplines and similar countries. Physics, Chemistry and Biology departments in Australia, Canada and the UK have been chosen.
In order to get a holistic picture of departments' Web use profiles and link patterns, five different perspectives are identified
and compared for each set of departments. Differences in link patterns are identified along both national and disciplinary
lines, and are found to reflect offline phenomena. Along national lines, a likely explanation for the difference is that countries
with better research performances make more general use of the Web; and, with respect to international peer interlinking,
countries that share more scholarly communication tend to interlink more with each other. Along disciplinary lines, it seems
that departments from disciplines which are more willing to distribute their research outputs tend to make more general use
of the Web, and also interlink more with their national and international peers. 相似文献
60.
Popp R.L. Pattipati K.R. Bar-Shalom Y. Ammar R.A. 《Parallel and Distributed Systems, IEEE Transactions on》1997,8(10):993-1005
The focus of this paper is to present the results of our investigation and evaluation of various shared-memory parallelizations of the data association problem in multitarget tracking. The multitarget tracking algorithm developed was for a sparse air traffic surveillance problem, and is based on an Interacting Multiple Model (IMM) state estimator embedded into the (2D) assignment framework. The IMM estimator imposes a computational burden in terms of both space and time complexity, since more than one filter model is used to calculate state estimates, covariances, and likelihood functions. In fact, contrary to conventional wisdom, for sparse multitarget tracking problems, we show that the assignment (or data association) problem is not the major computational bottleneck. Instead, the interface to the assignment problem, namely, computing the rather numerous gating tests and IMM state estimates, covariance calculations, and likelihood function evaluations (used as cost coefficients in the assignment problem), is the major source of the workload. Using a measurement database based on two FAA air traffic control radars, we show that a “coarse-grained” (dynamic) parallelization across the numerous tracks found in a multitarget tracking problem is robust, scalable, and demonstrates superior computational performance to previously proposed “fine-grained” (static) parallelizations within the IMM 相似文献