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Search Results: 1 - 10 of 5495 matches for " Markus "
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On the Ontology of Structural Realism  [PDF]
Markus Fischer
Open Journal of Political Science (OJPS) , 2019, DOI: 10.4236/ojps.2019.91008
Abstract: Due to its systemic approach, structural realism (or neorealism) can be subsumed under methodological holism, which takes social phenomena to be wholes that cannot be reduced to their parts. The wholes posited by structural realism are the state and the international structure. Recent developments in the philosophy of social science suggest that methodological holism ought to be limited to causal explanation and complemented by ontological individualism, which requires an account of how social wholes derive from individuals. Structural realism lacks such an account because it takes the state as an empirical given, mistaking for a fact what is really a concept in need of deductive derivation from individuals. To bring the theory methodologically up to date, this essay undertakes such a derivation of the state from individuals, proceeding in the deductive manner of political theory. It thus provides structural realism with a methodologically valid ontology, which, in turn, enables the theory to better defend itself against liberal and constructivist critics who reduce the state to a transient phenomenon.
Discretisation of stochastic control problems for continuous time dynamics with delay
Markus Fischer,Markus Reiss
Mathematics , 2006,
Abstract: As a main step in the numerical solution of control problems in continuous time, the controlled process is approximated by sequences of controlled Markov chains, thus discretising time and space. A new feature in this context is to allow for delay in the dynamics. The existence of an optimal strategy with respect to the cost functional can be guaranteed in the class of relaxed controls. Weak convergence of the approximating extended Markov chains to the original process together with convergence of the associated optimal strategies is established.
Spectral covolatility estimation from noisy observations using local weights
Markus Bibinger,Markus Rei?
Statistics , 2011,
Abstract: We propose localized spectral estimators for the quadratic covariation and the spot covolatility of diffusion processes which are observed discretely with additive observation noise. The eligibility of this approach to lead to an appropriate estimation for time-varying volatilities stems from an asymptotic equivalence of the underlying statistical model to a white noise model with correlation and volatility processes being constant over small intervals. The asymptotic equivalence of the continuous-time and the discrete-time experiments are proved by a construction with linear interpolation in one direction and local means for the other. The new estimator outperforms earlier nonparametric approaches in the considered model. We investigate its finite sample size characteristics in simulations and draw a comparison between the various proposed methods.
The Influence of Surface Energy on the Washing Quality of Filter Cakes  [PDF]
Markus Wilkens, Urs A. Peuker
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.14036
Abstract: The washing of filter cakes, especially the displacement washing, represents an important aspect in science researches and industrial applications. A lot of ongoing researches are focussed on impurities, which are dissolved in the mother liquid (e.g. sodium chloride) and washed out with the identical pure liquid without impurities. The project flushing focuses on systems with two chemically different liquids. The main aim is to exchange an organic solvent by water. This article focuses on the adsorption effects during a washing process with solid systems of different wetting behaviours.
Not All Shrivels Are Created Equal—Morpho-Anatomical and Compositional Characteristics Differ among Different Shrivel Types That Develop during Ripening of Grape (Vitis vinifera L.) Berries  [PDF]
Bhaskar Rao Bondada, Markus Keller
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.37105
Abstract: An understanding of physiological disorders associated with ripening of fruits triggered by abiotic stress relies on anatomical and physico-chemical analyses, as it provide insights into their origin and probable causes. The objective of this study was to analyze different ripening disorders of grape (Vitis vinifera L.) berries by dissecting their morpho-anatomy, shriveling nature, and composition. Four well-defined disorders—sunburn, prolonged dehydration (PD), late-season bunch stem necrosis (LBSN), and berry shrivel (BS) were analyzed in field-grown grapevines of the cultivar Cabernet Sauvignon. Early bunch stem necrosis (EBSN) that occurred before ripening was also included in the study. Unlike healthy spherical berries, the pericarp of disordered berries except for sunburn shriveled causing concomitant reductions in fresh weight and volume. The exocarp of PD berries developed well-ordered indentations as distinct from the wrinkles in LBSN berries, whereas BS berries were flaccid with numerous skin folds. The epicuticular wax occurred as upright platelets in all shrivel forms excluding the sun-exposed hemisphere of sunburned berries. A chlorophyllous inflorescence framework persisted in all shrivel forms but in LBSN, wherein the necrotic regions developed tylosis. Unlike the translucent mesocarp of healthy, sunburned, and PD berries, the mesocarp was collapsed in BS and LBSN berries, nevertheless all had well-developed seeds. The composition of healthy berries was optimal, whereas the disordered berries were compositionally distinct from each other, which as a whole differed from the healthy berries. The BS berries had the lowest sugar content, and although sugar concentration was higher in LBSN, sunburned and PD berries, sugar amount per berry was highest in the healthy berries, the same was true for hexoses. Healthy and BS berries exhibited highest amounts of tartaric acid followed by sunburn and PD berries, whereas the LBSN berries had the lowest values. Conversely, healthy and PD berries had the highest amounts of malic acid followed by LBSN, sunburn and BS berries, which collectively displayed similar amounts. The PD berries exhibited the highest calcium content followed by LBSN, healthy, and finally BS and sunburned berries. A linear relationship existed between potassium (K) and pH of the berries. The PD berries had the highest amounts of K followed by healthy, sunburn, LBSN, and BS berries. Overall, the results reported here provided combined morpho-anatomical and compositional analyses of different shrivel types that occurred during
Derivation of Moment Equations for the Theoretical Description of Electrons in Nonthermal Plasmas  [PDF]
Markus M. Becker, Detlef Loffhagen
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.33049

The derivation of moment equations for the theoretical description of electrons is of interest for modelling of gas discharge plasmas and semiconductor devices. Usually, certain artificial closure assumptions are applied in order to derive a closed system of moment equations from the electron Boltzmann equation. Here, a novel four-moment model for the description of electrons in nonthermal plasmas is derived by an expansion of the electron velocity distribution function in Legendre polynomials. The proposed system of partial differential equations is consistently closed by definition of transport coefficients that are determined by solving the electron Boltzmann equation and are then used in the fluid calculations as function of the mean electron energy. It is shown that the four-moment model can be simplified to a new drift-diffusion approximation for electrons without loss of accuracy, if the characteristic frequency of the electric field alteration in the discharge is small in comparison with the momentum dissipation frequency of the electrons. Results obtained by the proposed fluid models are compared to those of a conventional drift-diffusion approximation as well as to kinetic results using the example of low pressure argon plasmas. It is shown that the results provided by the new approaches are in good agreement with kinetic results and strongly improve the accuracy of fluid descriptions of gas discharges.

Double-dual types over the Banach space
Markus Pomper
International Journal of Mathematics and Mathematical Sciences , 2005, DOI: 10.1155/ijmms.2005.2533
Abstract: Let K be a compact Hausdorff space and C(K) the Banach space of all real-valued continuous functions on K, with the sup-norm. Types over C(K) (in the sense of Krivine and Maurey) can be uniquely represented by pairs (ℓ,u) of bounded real-valued functions on K, where ℓ is lower semicontinuous, u is upper semicontinuous, ℓ≤u, and ℓ(x)=u(x) for all isolated points x of K. A condition that characterizes the pairs (ℓ,u) that represent double-dual types over C(K) is given.
Double-dual -types over Banach spaces not containing
Markus Pomper
International Journal of Mathematics and Mathematical Sciences , 2004, DOI: 10.1155/s0161171204211152
Abstract: Let E be a Banach space. The concept of n-type overE is introduced here, generalizing the concept of type overE introduced by Krivine and Maurey. Let E″ be the second dual of E and fix g″1,…g″n∈E″. The function τ:E×ℝn→ℝ, defined by letting τ(x,a1,…,an)=‖x
Phosphate Metabolism in CKD Stages 3–5: Dietary and Pharmacological Control
Markus Ketteler
International Journal of Nephrology , 2011, DOI: 10.4061/2011/970245
Abstract: When compared to the available information for patients on dialysis (CKD stage 5D), data on the epidemiology and appropriate treatment of calcium and phosphate metabolism in the predialysis stages of chronic kidney disease (CKD) are quite limited. Perceptible derangements of calcium and phosphate levels start to become apparent when GFR falls below 30?mL/min in some, but not all, patients. However, hyperphosphatemia may be a significant morbidity and mortality risk predictor in predialysis CKD stages. The RIND study, evaluating progression of coronary artery calcification in incident hemodialysis patients, indirectly demonstrated that vascular calcification processes start to manifest in CKD patients prior to the dialysis stage, which may be closely linked to early and invisible derangements in calcium and phosphate homeostasis. Novel insights into the pathophysiology of calcium and phosphate handling such as the discovery of FGF23 and other phosphatonins suggest that a more complex assessment of phosphate balance is warranted, possibly including measurements of fractional phosphate excretion and phosphatonin levels in order to appropriately evaluate disordered metabolism in earlier stages of kidney disease. As a consequence, early and preventive treatment approaches may have to be developed for patients in CKD stages 3-5 to halt progression of CKD-MBD. 1. Introduction Availability of phosphate is of key importance for a number of normal physiological body functions including bone development, cellular membrane integrity (phospholipid content), and energy transfer (mitochondrial metabolism). Normal phosphate homeostasis, thus, maintains serum concentrations quite constantly between 0.8 and 1.45?mmol/L in the normal population. In this line, meals containing a high phosphate load in most instances do not acutely raise the serum phosphate levels, because phosphaturia may become augmented by as yet undefined mechanisms [1]. Furthermore, serum phosphate levels show rather a circadian rhythm which does not parallel intake (phosphate peaks in the early morning hours) [2]. In health, the kidney excretes approximately two thirds of the daily dietary phosphate load, and even with deteriorating kidney function in CKD, this excretion rate remains relatively well maintained [3]. Acute “unphysiological” oral phosphate intake is probably managed by the so-called phosphatonins or by adaptations of the filtered load [3, 4]. It appears that the body activates a number of potent systems in order to avoid both the occurrence of hyperphosphatemia. 2. Epidemiology of
On Self-Timed Circuits in Real-Time Systems
Markus Ferringer
International Journal of Reconfigurable Computing , 2011, DOI: 10.1155/2011/972375
Abstract: While asynchronous logic has many potential advantages compared to traditional synchronous designs, one of the major drawbacks is its unpredictability with respect to temporal behavior. Having no high-precision oscillator, a self-timed circuit's execution speed is heavily dependent on temperature and supply voltage. Small fluctuations of these parameters already result in noticeable changes of the design's throughput and performance. Without further provisions this jitter makes the use of asynchronous logic hardly feasible for real-time applications. We investigate the temporal characteristics of self-timed circuits regarding their usage in real-time systems, especially the Time-Triggered Protocol. We propose a simple timing model and elaborate a self-adapting circuit which shall derive a suitable notion of time for both bit transmission and protocol execution. We further introduce and analyze our jitter compensation concept, which is a threefold mechanism to keep the asynchronous circuit's notion of time tightly synchronized to the remaining communication participants. To demonstrate the robustness of our solution, we perform different tests and investigate their impact on jitter and frequency stability. 1. Introduction Asynchronous circuits elegantly overcome some of the limiting issues of their synchronous counterparts. The often-cited potential advantages of asynchronous designs are—among others—reduced power consumption and inherent robustness against changing operating conditions [1, 2]. Recent silicon technology additionally suffers from high parameter variations and high susceptibility to transient faults [3]. Asynchronous (delay insensitive) design offers a solution due to its inherent robustness. A substantial part of this robustness originates in the ability to adapt the speed of operation to the actual propagation delays of the underlying hardware structures, due to the feedback formed by completion detection and handshaking. While asynchronous circuits' adaptive speed is hence a desirable feature with respect to robustness, it becomes a problem in real-time applications that are based on a stable clock and a fixed (worst-case) execution time. Therefore, asynchronous logic is commonly considered inappropriate for such real-time applications, which excludes its use in an important share of fault-tolerant applications that would highly benefit from its robustness. Consequently, it is reasonable to take a closer look at the actual stability and predictability of asynchronous logic's temporal behavior. After all, synchronous designs operate on
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