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121.
Joachim von zur Gathen 《Applicable Algebra in Engineering, Communication and Computing》2011,22(3):165-185
A polynomial f (multivariate over a field) is decomposable if f=g °h{f=g \circ h} with g univariate of degree at least 2. We determine the dimension (over an algebraically closed field) of the set of decomposables,
and an approximation to their number over a finite field. The relative error in our approximations is exponentially decaying
in the input size. 相似文献
122.
The human visual system is often able to learn to recognize difficult object categories from only a single view, whereas automatic object recognition with few training examples is still a challenging task. This is mainly due to the human ability to transfer knowledge from related classes. Therefore, an extension to Randomized Decision Trees is introduced for learning with very few examples by exploiting interclass relationships. The approach consists of a maximum a posteriori estimation of classifier parameters using a prior distribution learned from similar object categories. Experiments on binary and multiclass classification tasks show significant performance gains 相似文献
123.
Using a computer-based scientific discovery learning environment on buoyancy in fluids we investigated the effects of goal specificity (nonspecific goals vs. specific goals) for two goal types (problem solving goals vs. learning goals) on strategy use and instructional efficiency. Our empirical findings close an important research gap, because in earlier studies the goal specificity effect either was restricted to one goal type or goal type was confounded with goal specificity. In addition, there is hardly a study with empirical evidence for the goal specificity effect on strategy use, which counts even more for a cognitive cost-benefit ratio as a dependent variable. Instead, in earlier studies the goal specificity effect has been attributed to differences in strategy use and cognitive cost-benefit ratio in a rather theoretical way. In the present study for strategy use an interaction was found between goal specificity and goal type, indicating that the goal specificity effect occurs only in case of problem solving goals, but not in case of learning goals. Compared to students provided with specific problem solving goals, students who worked on nonspecific problem solving goals, used a control of variables-strategy more frequently. Additionally, we found a main effect of goal specificity on instructional efficiency for both of the goal types, pointing at a more favorable relationship between performance gain and cognitive load caused by nonspecific goals. 相似文献
124.
Michael Breuß Henning Zimmer Joachim Weickert 《Journal of Mathematical Imaging and Vision》2011,39(3):230-244
Optic flow and stereo reconstruction are important examples of correspondence problems in computer vision. Correspondence
problems have been studied for almost 30 years, and energy-based methods such as variational approaches have become popular
for solving this task. However, despite the long history of research in this field, only little attention has been paid to
the numerical approximation of derivatives that naturally occur in variational approaches. 相似文献
125.
Kiesel Andrea; Kunde Wilfried; Pohl Carsten; Berner Michael P.; Hoffmann Joachim 《Canadian Metallurgical Quarterly》2009,35(1):292
Expertise in a certain stimulus domain enhances perceptual capabilities. In the present article, the authors investigate whether expertise improves perceptual processing to an extent that allows complex visual stimuli to bias behavior unconsciously. Expert chess players judged whether a target chess configuration entailed a checking configuration. These displays were preceded by masked prime configurations that either represented a checking or a nonchecking configuration. Chess experts, but not novice chess players, revealed a subliminal response priming effect, that is, faster responding when prime and target displays were congruent (both checking or both nonchecking) rather than incongruent. Priming generalized to displays that were not used as targets, ruling out simple repetition priming effects. Thus, chess experts were able to judge unconsciously presented chess configurations as checking or nonchecking. A 2nd experiment demonstrated that experts' priming does not occur for simpler but uncommon chess configurations. The authors conclude that long-term practice prompts the acquisition of visual memories of chess configurations with integrated form-location conjunctions. These perceptual chunks enable complex visual processing outside of conscious awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
126.
Joachim Mittendorf Prof. Dr. Stefan Weigand Dr. Cristina Alonso‐Alija Dr. Erwin Bischoff Dr. Achim Feurer Dr. Michael Gerisch Dr. Armin Kern Dr. Andreas Knorr Dr. Dieter Lang Dr. Klaus Muenter Dr. Martin Radtke Dr. Hartmut Schirok Dr. Karl‐Heinz Schlemmer Dr. Elke Stahl Dr. Alexander Straub Dr. Frank Wunder Dr. Johannes‐Peter Stasch Dr. 《ChemMedChem》2009,4(5):693-693
127.
128.
129.
Kesarin Chaleepa Anik Szepes Joachim Ulrich 《European Journal of Lipid Science and Technology》2010,112(5):565-573
The metastable zone width (MZW) of a multi‐component system as influenced by the process parameters cooling rate, agitation speed, and additive concentration was determined via ultrasound velocity measurements. The results were compared with those obtained by optical back‐reflectance measurements (ORM) using coconut oil as a model substance. Increasing the cooling rate led to the shift of the nucleation point to lower temperatures. This tendency was better visualized by the ultrasonic curves while a significant disturbance of the ORM signal could be observed. Agitation led to an increase of the nucleation temperature and hence a narrower metastable zone. The influence of an additive on the MZW was found to strongly depend on its concentration. The MZW detected by the ultrasound technique was narrower compared to that obtained by the ORM method, indicating the faster response to the phase transition of the ultrasound technique. Another advantage of the ultrasound technique was the in situ evaluation of the experimental data, while ORM needed a linear fitting to estimate the saturation temperature. Furthermore, ultrasound velocity measurements are based on density determination of the medium whereas the ORM sensor is able to detect only particles that are located within the measuring zone and possess a well‐defined size. Practical applications: MZW is one of the most important parameters that determine the characteristics of crystalline products. However, a proper technique that can be used in MZW detection in fat systems has rarely been reported, due to the difficulties in dealing with natural fats. The findings of this study can greatly help those who are involved in the field of fat crystallization from both the academic and the practical point of view. This is due to the fact that new and promising techniques for the online and in situ determination of the MZW of fats, with high accuracy, and reproducibility, under most process conditions, were clarified in this work. The readers can easily follow the procedure developed in this paper. Also information about the influence of process parameters and additives on the MZW is included. 相似文献
130.
This paper deals with terrestrial worm-like locomotion systems living in a straight line. They are modeled as chains of mass points having ground interaction via spikes which make the velocities unidirectional. A method is presented to construct gaits with any desired time pattern of resting mass points (which are acted on by the propulsive forces). Taking the dynamics into consideration, conclusions about the choice and shift of gaits in connection with actuator data are given. 相似文献