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121.
FTIR data from Re2O7/-Al2O3 metathesis catalysts indicate that a low Re contents ReO4 ions have predominantly reacted with basic surface OH groups, while at higher Re2O7 loadings they have also reacted with neutral and more acidic OH groups.On phosphated -Al2O3 the phosphate has reacted with the more acidic OH groups on the -Al2O3; in catalysts based on this support, the ReO4
– ions have also reacted with the phosphorus-bonded OH groups already at low Re2O7 loadings, resulting in more active catalysts. 相似文献
122.
123.
Robert Rieger Martin Schuettler Dipankar Pal Chris Clarke Peter Langlois John Taylor Nick Donaldson 《IEEE transactions on neural systems and rehabilitation engineering》2006,14(4):427-437
In this paper, we describe the design and testing of a system for recording electroneurographic signals (ENG) from a multielectrode nerve cuff (MEC). This device, which is an extension of the conventional nerve signal recording cuff, enables ENG to be classified by action potential velocity. In addition to electrical measurements, we provide preliminary in vitro data obtained from frogs that demonstrate the validity of the technique for the first time. Since typical ENG signals are extremely small, on the order of 1 1 microV, very low-noise, high-gain amplifiers are required. The ten-channel system we describe was realized in a 0.8 microm CMOS technology and detailed measured results are presented. The overall gain is 10 000 and the total input-referred root mean square (rms) noise in a bandwidth 1 Hz-5 kHZ is 291 nV. The active area is 12 mm(2) and the power consumption is 24 mW from +/-2.5 V power supplies. 相似文献
124.
Evaluating water quality data for outliers is a good quality control/quality assessment procedure whether the data are used for monitoring or for modeling. Often water quality data are correlated, e.g., carbonaceous biochemical oxygen demand (CBOD) has some correlation with NH3. Univariate methods for identifying outliers do not consider the correlation between variables and may identify too many data points as outliers or miss observations which have extreme ratios between variables, e.g., a raw wastewater sample with relatively low CBOD but high NH3. Testing for outliers using multivariate methods such as the Mahalanobis distance, Jackknife distance, p-values, or Hadi’s automatically incorporates the correlation or covariance between variables and is fundamentally more correct. Such multivariate methods can better identify potential outliers and avoid eliminating valid data. 相似文献
125.
Oxidation state of titanium was determined in CaO‐SiO2‐TiOx slags in the composition range 25‐53 percent CaO, 27‐46 percent SiO2, 10‐55 percent TiOx at 1873K using gas equilibration method. In the experiments, slags with different titanium oxide contents were equilibrated with a known carbon monoxide and carbon dioxide ratio. The results were used to determine the Ti3+ and Ti4+ contents as well as the activity coefficient ratio of corresponding oxides in the slag. The dependence of the activity coefficient ratio as a function of oxygen partial pressure was determined. 相似文献
126.
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
127.
Abstract: Just like rough set theory, fuzzy set theory addresses the topic of dealing with imperfect knowledge. Recent investigations have shown how both theories can be combined into a more flexible, more expressive framework for modelling and processing incomplete information in information systems. At the same time, intuitionistic fuzzy sets have been proposed as an attractive extension of fuzzy sets, enriching the latter with extra features to represent uncertainty (on top of vagueness). Unfortunately, the various tentative definitions of the concept of an ‘intuitionistic fuzzy rough set’ that were raised in their wake are a far cry from the original objectives of rough set theory. We intend to fill an obvious gap by introducing a new definition of intuitionistic fuzzy rough sets, as the most natural generalization of Pawlak's original concept of rough sets. 相似文献
128.
Floris Bex Henry Prakken Chris Reed Douglas Walton 《Artificial Intelligence and Law》2003,11(2-3):125-165
This paper studies the modelling of legal reasoning about evidence within general theories of defeasible reasoning and argumentation. In particular, Wigmore's method for charting evidence and its use by modern legal evidence scholars is studied in order to give a formal underpinning in terms of logics for defeasible argumentation. Two notions turn out to be crucial, viz. argumentation schemes and empirical generalisations. 相似文献
129.
Chris Reed 《AI & Society》1997,11(1-2):138-154
The concept of argumentation in AI is based almost exclusively on the use of formal, abstract representations. Despite their
appealing computational properties, these abstractions become increasingly divorced from their real world counterparts, and,
crucially, lose the ability to express the rich gamut of natural argument forms required for creating effective text. In this
paper, the demands that socially situated argumentation places on knowledge representation are explored, and the various problems
with existing formalisations are discussed. Insights from argumentation theory and social psychology are then adduced as key
contributions to a notion of social context which is both computationally tractable and suitably expressive for handling the
complexities of argumentation found in natural language. 相似文献
130.
Symmetric multiprocessor systems are increasingly common, not only as high-throughput servers, but as a vehicle for executing
a single application in parallel in order to reduce its execution latency. This article presents Pedigree, a compilation tool
that employs a new partitioning heuristic based on the program dependence graph (PDG). Pedigree creates overlapping, potentially
interdependent threads, each executing on a subset of the SMP processors that matches the thread’s available parallelism.
A unified framework is used to build threads from procedures, loop nests, loop iterations, and smaller constructs. Pedigree
does not require any parallel language support; it is post-compilation tool that reads in object code. The SDIO Signal and
Data Processing Benchmark Suite has been selected as an example of real-time, latency-sensitive code. Its coarse-grained data
flow parallelism is naturally exploited by Pedigree to achieve speedups of 1.63×/2.13× (mean/max) and 1.71×/2.41× on two and
four processors, respectively. There is roughly a 20% improvement over existing techniques that exploit only data parallelism.
By exploiting the unidirectional flow of data for coarse-grained pipelining, the synchronization overhead is typically limited
to less than 6% for synchronization latency of 100 cycles, and less than 2% for 10 cycles.
This research was supported by ONR contract numbers N00014-91-J-1518 and N00014-96-1-0347. We would like to thank the Pittsburgh
Supercomputing Center for use of their Alpha systems. 相似文献