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排序方式: 共有301条查询结果,搜索用时 31 毫秒
1.
Jonathan P. Caulkins Dieter Grass Gustav Feichtinger Gernot Tragler 《Computers & Operations Research》2008
This paper deals dynamically with the question of how recruitment to terror organizations is influenced by counter-terror operations. This is done within an optimal control model, where the key state is the (relative) number of terrorists and the key controls are two types of counter-terror tactics, one (“water”) that does not and one (“fire”) that does provoke recruitment of new terrorists. The model is nonlinear and does not admit analytical solutions, but an efficient numerical implementation of Pontryagin's minimum principle allows for solution with base case parameters and considerable sensitivity analysis. Generally, this model yields two different steady states, one where the terror organization is nearly eradicated and one with a high number of terrorists. Whereas water strategies are used at almost any time, it can be optimal not to use fire strategies if the number of terrorists is below a certain threshold. 相似文献
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We study a family of problems, called Maximum Solution (Max Sol), where the objective is to maximise a linear goal function over the feasible integer assignments to a set of variables subject
to a set of constraints. When the domain is Boolean (i.e. restricted to {0,1}), the maximum solution problem is identical
to the well-studied Max Ones problem, and the complexity and approximability is completely understood for all restrictions on the underlying constraints.
We continue this line of research by considering the Max Sol problem for relations defined by regular signed logic over finite subsets of the natural numbers; the complexity of
the corresponding decision problem has recently been classified by Creignou et al. (Theory Comput. Syst. 42(2):239–255, 2008). We give sufficient conditions for when such problems are polynomial-time solvable and we prove that they are APX-hard otherwise. Similar dichotomies are also obtained for variants of the Max Sol problem. 相似文献
4.
A comparison is made between synchronous motors and induction motors with regard to industrial power system stability. Representation of motor loads in stability studies is reviewed. The specific system studied is an infinite bus supplying a combination induction and synchronous motor load through a transmission line and transformer. The system is subjected to a fault at the transformer and critical values of fault clearing time are computer calculated for ratios of synchronous motor load to induction motor load from zero to unity. The effect of variation of motor parameters on clearing times is discussed. 相似文献
5.
Magnetic tracking is a popular technique that exploits static and low-frequency magnetic fields for positioning of quasi-stationary objects. One important system design aspect, which substantially influences the performance of the tracking system, is how to collect as much information as possible with a given number of measurements. In this work, we optimize the allocation of measurements given a large number of possible measurements of a generic magnetic tracking system that exploits time-division multiplexing. We exploit performance metrics based on the Fisher information matrix. In particular, the performance metrics measure worst-case or average performance in a measurement domain, i.e. the domain where the tracking is to be performed. An optimization problem with integer variables is formulated. By relaxing the constraint that the variables should be integer, a convex optimization problem is obtained. The two performance metrics are compared for several realistic measurement scenarios with planar transmitter constellations. The results show that the worst performance is obtained in the most distant parts of the measurement domain. Furthermore, measurement allocations optimized for worst-case performance require measurements in a larger area than measurement allocations optimized for average performance. 相似文献
6.
Simon Alexanderson Gustav Eje Henter Taras Kucherenko Jonas Beskow 《Computer Graphics Forum》2020,39(2):487-496
Automatic synthesis of realistic gestures promises to transform the fields of animation, avatars and communicative agents. In off-line applications, novel tools can alter the role of an animator to that of a director, who provides only high-level input for the desired animation; a learned network then translates these instructions into an appropriate sequence of body poses. In interactive scenarios, systems for generating natural animations on the fly are key to achieving believable and relatable characters. In this paper we address some of the core issues towards these ends. By adapting a deep learning-based motion synthesis method called MoGlow, we propose a new generative model for generating state-of-the-art realistic speech-driven gesticulation. Owing to the probabilistic nature of the approach, our model can produce a battery of different, yet plausible, gestures given the same input speech signal. Just like humans, this gives a rich natural variation of motion. We additionally demonstrate the ability to exert directorial control over the output style, such as gesture level, speed, symmetry and spacial extent. Such control can be leveraged to convey a desired character personality or mood. We achieve all this without any manual annotation of the data. User studies evaluating upper-body gesticulation confirm that the generated motions are natural and well match the input speech. Our method scores above all prior systems and baselines on these measures, and comes close to the ratings of the original recorded motions. We furthermore find that we can accurately control gesticulation styles without unnecessarily compromising perceived naturalness. Finally, we also demonstrate an application of the same method to full-body gesticulation, including the synthesis of stepping motion and stance. 相似文献
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8.
K. Gustav U. Bartsch H. Schütz R. Machinek W. Lüttke 《Advanced Synthesis \u0026amp; Catalysis》1991,333(1):101-105
Spectroscopic Investigations on Organic Carbonyl Compounds. VI. N.M.R.-Studies on Substituted β;-Diketones and their Vinyloge Derivatives . 13C- and 1H-n.m.r.-data of substituted β-diketones and their vinyloge derivatives are presented. Most of the compounds exist chiefly in the enol-form. Only in the case of 4-dimethyl-aminodibenzoylmethane a keto-enol-equilibrium is registered. The influence of the substituent A and the chainlength on the position of the enol proton is discussed. 相似文献
9.
Underlying the completely-optimized S0 and T1 molecular geometries of isomeric terphenyls the corresponding theoretical vibronic T1 → S0 ‘line’ spectra calculated within the CONDON approach, are presented and compared with the experimental phosphorescences. The influence of possible conformations on the vibronic spectral behaviour is studied theoretically. The DUSHINSKY effect is found to be most important to the T1 → S0 phosphorescence of m-terphenyl. An analysis of the spectroscopically relevant vibrational modes is given. 相似文献
10.
Stephan Bose-O'Reilly Gustav Drasch Saulo Rodrigues-Filho Beate Lettmeier Alexandra Maydl Uwe Siebert 《The Science of the total environment》2010,408(4):713-1000
Small scale miners use mercury to extract gold from ore in many countries. An environmental and health assessment was performed in Indonesia in two regions, Galangan in Central Kalimantan and Talawaan in Northern Sulawesi. The environmental assessment showed severe mercury contamination of the sediments, and increased mercury levels in local fish. For the health investigation 281 volunteers were recruited and examined by a standardized questionnaire, a neurological examination and neuro-psychological tests. A medical score was used consisting of significant factors of mercury intoxication. Mercury exposed workers showed typical symptoms of mercury intoxication, such as movement disorders (ataxia, tremor, dysdiadochokinesia, etc.). Blood, urine and hair samples were taken from any participant and analyzed for mercury. The mercury concentration in the biomonitors was high, partly extreme high in the working population, increased in the population living in the same habitat and low in the control group. By a standard protocol which includes a combination of threshold values of mercury in the biomonitors and a medical sum score the diagnosis of chronic mercury intoxication was made for highly burdened workers (amalgam smelters) in 55% in Sulawesi and in 62% in Kalimantan. Less exposed mineral processors and the general population in the mining areas were also intoxicated to a high percentage. 相似文献