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Sambasiva Rao Chinnamsetty Mike Espig Wolfgang Hackbusch 《Computing and Visualization in Science》2015,17(6):267-275
The computation of a six-dimensional density matrix is the crucial step for the evaluation of kinetic energy in electronic structure calculations. For molecules with heavy nuclei, one has to consider a very refined mesh in order to deal with the nuclear cusps. This leads to high computational time and needs huge memory for the computation of the density matrix. To reduce the computational complexity and avoid discretization errors in the approximation, we use mesh-free canonical tensor products in electronic structure calculations. In this paper, we approximate the six-dimensional density matrix in an efficient way and then compute the kinetic energy. Accuracy is examined by comparing our computed kinetic energy with the exact computation of the kinetic energy. 相似文献
13.
Wolfgang Schwack Steven Nyanzi 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1994,198(1):3-7
The application of second-derivative UV-spectroscopy offers a highly sensitive and selective method for the determination of CS2 and COS, as acid hydrolysis products of dithiocarbamate und thiuram disulphide fungicides, using a methanolic amine absorption reagent (ethylenediamine, piperidine). With standard concentrations of 0.08–1.1 g CS2/ml and 0.3 to 2.0 g COS/ml, respectively, calibration curves with good correlation coefficients (r>0.999) were obtained. In comparison to the official method of the Deutsche Forschungsgemeinschaft (DFG method S15) the proposed alternative is at least 100 times more sensitive to CS2. Using the second derivative method it is possible not only to clearly differentiate between CS2 and COS but also to quantify both gases without resorting to tedious background corrections as compared to the direct photometric methods. Additionally, second derivative spectroscopy allows the direct determination of thiram in the concentration range 1–10 g/ml after its extraction with chloroform. For example, thiram in water (10 g/l) and in thiram/talc standards (10 mg/g) were determined with good precision (±2.0%).
Analytik der Dithiocarbamat-Fungicide. Bestimmung von CS2, COS sowie Thiram (TMTD) mittels Derivativ-UV-Spektroskopie
Zusammenfassung Die Anwendung der Derivativ-UV-Spektroskopie (2. Ableitung) erlaubt eine sehr empfindliche Bestimmung von CS2 und COS als Hydrolyseprodukte der Dithiocarbamat- und Thiuramdisulfid-Fungicide nach Absorption in einem methanolischem Amin-Reagens (Ethylendiamin, Piperidin). Mit Standard-Konzentrationen von 0,08–1,1 g CS2/ml bzw. 0,3–2,0 g COS/ml zeigten die Eichgeraden gute Korrelationskoeffizienten (r<0,999). Im Vergleich zur DFG-Methode S15 zeichnet sich die vorgeschlagene Alternative durch eine um zwei Zehnerpotenzen höhere Empfindlichkeit bei der CS2-Bestimmung aus. In der 2. Ableitung wird nicht nur die Unterscheidung von COS und CS2 eindeutig, sondern auch deren Quantifizierung ohne rechnerische Untergrundkorrekturen ermöglicht. Mit Hilfe der Derivativspektroskopie konnte außerdem Thiram (TMTD) in Konzentrationen von 1–10 g/ml direkt erfaßt werden. So ließen sich nach Extraktion mit Chloroform 10 g/L Thiram in Wasser mit einer Präzision von ±2,0% direkt bestimmen oder Thiram/Talkum-Standards (10 mg/g) überprüfen.相似文献
14.
Evolving Teams of Predictors with Linear Genetic Programming 总被引:1,自引:0,他引:1
This paper applies the evolution of GP teams to different classification and regression problems and compares different methods for combining the outputs of the team programs. These include hybrid approaches where (1) a neural network is used to optimize the weights of programs in a team for a common decision and (2) a realnumbered vector (the representation of evolution strategies) of weights is evolved with each term in parallel. The cooperative team approach results in an improved training and generalization performance compared to the standard GP method. The higher computational overhead of team evolution is counteracted by using a fast variant of linear GP. 相似文献
15.
Kim Wüllenweber Daniel Beimborn Tim Weitzel Wolfgang König 《Information Systems Frontiers》2008,10(2):211-224
What is the impact of business process standardization on business process outsourcing (BPO) success? This paper argues that there is a direct impact of process standardization on BPO success, due to production cost economies, and also an indirect effect via improved contractual and relational governance resulting from better monitoring opportunities and facilitated communication and coordination. This threefold impact of standardization on BPO success is empirically confirmed using data from 335 BPO ventures in 215 German banks. 相似文献
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Pradeep K. Nalla Roland J. Weiss Prakash Peranandam Jürgen Ruf Thomas Kropf Wolfgang Rosenstiel 《Electronic Notes in Theoretical Computer Science》2006,135(2):47
In this paper we describe an algorithm for distributed, BDD-based bounded property checking and its implementation in the verification tool SymC. The distributed algorithm verifies larger models and returns results faster than the sequential version.The core algorithm distributes partitions of the state set to computation nodes after reaching a threshold size. The nodes proceed with image computation on the nodes asynchronously. The main scalability problem of this scheme is the overlap of state set partitions. We present static and dynamic overlap reduction techniques. 相似文献
18.
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
19.
Tim Weitzel Daniel Beimborn Wolfgang König 《Information Systems and E-Business Management》2003,1(2):189-211
Networks utilizing modern communication technologies can offer competitive advantages to those using them wisely. But due
to the existence of network effects, planning and operating cooperation networks is difficult. In this paper, the strategic
situation of individual agents deciding on network participation is analysed. A systematic equilibrium analysis using computer-based
simulations reveals principal solution scenarios for network agents and shows that network cooperation problems might frequently
be not as difficult to resolve as often feared. In particular, strategic situations are identified showing that a majority
of individuals might be better off getting the optimal solution from a central principal and that in many cases simple information
intermediation can solve the start-up problem notorious in network economics. 相似文献
20.
A dichoptic masking procedure was used to test whether the mask-dependent cuing effects found in luminance detection by P. L. Smith (2000a) were due to integration masking or interruption masking. Attentional cuing enhanced detection sensitivity (d') when stimuli were backwardly masked with either dichoptic or monoptic masks, whereas no cuing effect was found with unmasked stimuli, implying the mask dependencies were due to interruption of stimulus processing in visual cortex by the mask. The effect is predicted by a gated diffusion process model in which masks interrupt stimulus processing and attention controls the flow of information to a sequential-sampling decision mechanism. The model correctly predicts different patterns of performance for detection and discrimination and cuing effects in simple reaction time. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献