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1062. A stable and optimal complexity solution method for mixed finite element discretizations
- Creator:
- Brandts, Jan and Stevenson, Rob
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- mixed finite elements and multi-level solver
- Language:
- English
- Description:
- We outline a solution method for mixed finite element discretizations based on dissecting the problem into three separate steps. The first handles the inhomogeneous constraint, the second solves the flux variable from the homogeneous problem, whereas the third step, adjoint to the first, finally gives the Lagrangian multiplier. We concentrate on aspects involved in the first and third step mainly, and advertise a multi-level method that allows for a stable computation of the intermediate and final quantities in optimal computational complexity.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1063. A standardised terminology of the embryonic envelopes and associated developmental stages of tapeworms (Platyhelminthes: Cestoda)
- Creator:
- Conn, David Bruce and Świderski, Zdzisław
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Cestoda, coracidium, embryogenesis, hexacanth, embryonic envelope, and oncosphere
- Language:
- English
- Description:
- Over the past 40 years, much has been published on the ultrastructure and cellular development of embryonic structures in a wide range of cestodes. However, the literature contains many discrepancies in both terminology and interpretations because of the facts that these organisms are phylogenetically diverse within their respective orders and families, the habitats that affect embryonic envelope structure are diverse, and the work has been done in various laboratories around the world. This review and synthesis was initiated by a working group of biologists from around the world convened at the Fifth International Workshop on Cestode Systematics and Phylogeny in České Budĕjovice, at the Institute of Parasitology of the Biology Centre, Academy of Sciences of the Czech Republic. It brings together the data from published work and establishes a uniform terminology and interpretation based on the data as they are presented. A consensus was reached for standardised definitions of the oncosphere, hexacanth, coracidium, embryonic envelopes, outer envelope, inner envelope, embryophore, vitelline capsule, shell, and outer coat. All of these are defined as components of the embryo or its vitellocyte-derived or uterine-derived coatings.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1064. A statistical approach to blind source separation
- Creator:
- Rai, C. S. and Singh, Yogesh
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Blind Source Separation (BSS), objective function, edgeworth expansion, sub-Gaussian sources, and super-Gaussian sources
- Language:
- English
- Description:
- Different methods for Blind Source Separation (BSS) have been recently proposed. Most of these methods are suitable for separating either a mixture of sub-Gaussian source or a mixture of super-Gaussian sources. In this paper, a unified statistical approach for separating the mixture of sub-Gaussian and super-Gaussian source is proposed. Source separation techniques use an objective function to be optimized. The optimization process requires probability density function to be expressed in the terms of the random variable. Two different density models have been used for representing sub-Gaussian and super-Gaussian sources. Optimization of the objective function yields different nonlinear functions. Kurtosis has been ušed as measure of Gaussianity of a source. Depending upon the sign of kurtosis one of the nonlinearities is ušed in the proposed algorithm. Simulations with artificiaily generated as well as audio signals demonstrate effectiveness of the proposed approach.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1065. A step to Kurzweil-Henstock-an outline
- Creator:
- Craven, B. D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- integral, Kurzweil-Henstock integral, step-function, and filterbase
- Language:
- English
- Description:
- A short approach to the Kurzweil-Henstock integral is outlined, based on approximating a real function on a compact interval by suitable step-functions, and using filterbase convergence to define the integral. The properties of the integral are then easy to establish.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1066. A stochastic approach to the operative control of flood flows through a reservoir
- Creator:
- Jaroš, Lubomír, Starý, Miloš, and Březková, Lucie
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- operative control of reservoir, artificial intelligence, fuzzy inference system, neural networks, stochastic forecast, stochastic control of reservoir, and principle of adaptation
- Language:
- Slovak
- Description:
- The contribution focuses on the design of a control algorithm aimed at the operative control of runoff water from a reservoir during flood situations. Management is based on the stochastically specified forecast of water inflow into the reservoir. From a mathematical perspective, the solved task presents the control of a dynamic system whose predicted hydrological input (water inflow) is characterised by significant uncertainty. The algorithm uses a combination of simulation model data, in which the position of the bottom outlets is sought via nonlinear optimisation methods, and artificial intelligence methods (adaptation and fuzzy model). The task is written in the technical computing language MATLAB using the Fuzzy Logic Toolbox.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1067. A stochastic mirror-descent algorithm for solving AXB=C over an multi-agent system
- Creator:
- Wang, Yinghui and Cheng, Songsong
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- multi-agent system, sublinear convergence, stochastic mirror descent algorithm, and distributed computation of matrix equation
- Language:
- English
- Description:
- In this paper, we consider a distributed stochastic computation of AXB=C with local set constraints over an multi-agent system, where each agent over the network only knows a few rows or columns of matrixes. Through formulating an equivalent distributed optimization problem for seeking least-squares solutions of AXB=C, we propose a distributed stochastic mirror-descent algorithm for solving the equivalent distributed problem. Then, we provide the sublinear convergence of the proposed algorithm. Moreover, a numerical example is also given to illustrate the effectiveness of the proposed algorithm.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1068. A stochastic programming approach to managing liquid asset portfolios
- Creator:
- Raubenheimer, Helgard and Kruger, Machiel F.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- stochastic programming, portfolio optimization, and liquid assets
- Language:
- English
- Description:
- Maintaining liquid asset portfolios involves a high carry cost and is mandatory by law for most financial institutions. Taking this into account a financial institution's aim is to manage a liquid asset portfolio in an "optimal" way, such that it keeps the minimum required liquid assets to comply with regulations. In this paper we propose a multi-stage dynamic stochastic programming model for liquid asset portfolio management. The model allows for portfolio rebalancing decisions over a multi-period horizon, as well as for flexible risk management decisions, such as reinvesting coupons, at intermediate time steps. We show how our problem closely relates to insurance products with guarantees and utilize this in the formulation. We will discuss our formulation and implementation of a multi-stage stochastic programming model that minimizes the down-side risk of these portfolios. The model is back-tested on real market data over a period of two years
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1069. A stopping rule for discounted Markov decision processes with finite action sets
- Creator:
- Montes-de-Oca, Raúl, Lemus-Rodríguez, Enrique, and Cruz-Suárez, Daniel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Markov decision process, ergodicity condition, value iteration, discounted cost, optimal policy, and myopic policies
- Language:
- English
- Description:
- In a Discounted Markov Decision Process (DMDP) with finite action sets the Value Iteration Algorithm, under suitable conditions, leads to an optimal policy in a finite number of steps. Determining an upper bound on the necessary number of steps till gaining convergence is an issue of great theoretical and practical interest as it would provide a computationally feasible stopping rule for value iteration as an algorithm for finding an optimal policy. In this paper we find such a bound depending only on structural properties of the Markov Decision Process, under mild standard conditions and an additional "individuality" condition, which is of interest in its own. It should be mentioned that other authors find such kind of constants using non-structural information, i.e., information not immediately apparent from the Decision Process itself. The DMDP is required to fulfill an ergodicity condition and the corresponding ergodicity index plays a critical role in the upper bound.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1070. A strong invariance principle for negatively associated random fields
- Creator:
- Cai, Guang-Hui
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- strong invariance principle, negative association, random field, blocking technique, and quantile transform
- Language:
- English
- Description:
- In this paper we obtain a strong invariance principle for negatively associated random fields, under the assumptions that the field has a finite $(2+\delta )$th moment and the covariance coefficient $u(n)$ exponentially decreases to $0$. The main tools are the Berkes-Morrow multi-parameter blocking technique and the Csörgő-Révész quantile transform method.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public