Some light-traffic and heavy-traffic results for the <Emphasis Type="Italic">GI</Emphasis>/<Emphasis Type="Italic">G</Emphasis>/<Emphasis Type="Italic">n</Emphasis>/0 queue using the <Emphasis Type="Italic">GM Heuristic</Emphasis>

In this paper we carry out both light-traffic and heavy-traffic analyses for the calculation of steady-state loss probabilities in the general multi-server queuing loss system, the GI/G/n/0 queue. The analysis makes use of a heuristic approach called the GM Heuristic, for which a detailed analysis in normal traffic has previously been published. Sufficient conditions are given for the GM Heuristic to be asymptotically exact in light traffic. The heuristic is also shown to be asymptotically exact in heavy-traffic when the number of servers n tends to infinity. These results are illustrated numerically using two-phase Coxian distributions for both the inter-arrival time and service time.     

The Stationary Characteristics of the <Emphasis Type="Italic">G</Emphasis>/<Emphasis Type="Italic">MSP</Emphasis>/1/<Emphasis Type="Italic">r</Emphasis> Queueing System

A single-server queueing system with recurrent input flow and Markov service process is considered. Both the cases of finite and infinite buffers are investigated. The analysis of this system is based on the method of embedded Markov chain. The main stationary characteristics of system performance are derived.     

<Emphasis Type="Italic">Wissensmanagement</Emphasis>

In dieser Arbeit wird anhand von zwei konkreten Beispielen erl?utert, was Wissensmanagement (WM) ist und warum WM eine so wichtige Rolle in der Zukunft spielen wird. Dies gilt freilich nur, wenn es sich bei WM um mehr handelt als die Verwendung von Informationssystemen oder verteilten Datenbanken für anspruchsvolle Aufgaben.     

Extensions of fuzzy hyperideals in <Emphasis Type="Italic">H</Emphasis><Subscript><Emphasis Type="Italic">V</Emphasis></Subscript>-semigroups

The object of the present paper is the investigation and study of (fuzzy) hyperideals in H _v - semigroups. Regular equivalence relations play in H _v - semigroup theory a role analogous to congruences in semigroup theory, so we introduce fuzzy regular equivalence relations on H _v -semigroups and then we study fuzzy Rees regular relations on H _v -semigroups. Using this ideas, we establish a relation between fuzzy hyperideal of an H _v -semigroup H and fuzzy hyperideal of a quotient H _v -semigroup of H. Some characterizations of them are then shown.      

An Augmented Lagrangian Method for <Emphasis Type="Italic">TV</Emphasis><Subscript><Emphasis Type="Italic">g</Emphasis></Subscript>+<Emphasis Type="Italic">L</Emphasis><Superscript>1</Superscript>-norm Minimization

In this paper, the minimization of a weighted total variation regularization term (denoted TV _g ) with L ¹ norm as the data fidelity term is addressed using the Uzawa block relaxation method. The unconstrained minimization problem is transformed into a saddle-point problem by introducing a suitable auxiliary unknown. Applying a Uzawa block relaxation method to the corresponding augmented Lagrangian functional, we obtain a new numerical algorithm in which the main unknown is computed using Chambolle projection algorithm. The auxiliary unknown is computed explicitly. Numerical experiments show the availability of our algorithm for salt and pepper noise removal or shape retrieval and also its robustness against the choice of the penalty parameter. This last property is useful to attain the convergence in a reduced number of iterations leading to efficient numerical schemes. The specific role of the function g in TV _g is also investigated and we highlight the fact that an appropriate choice leads to a significant improvement of the denoising results. Using this property, we propose a whole algorithm for salt and pepper noise removal (denoted UBR-EDGE) that is able to handle high noise levels at a low computational cost. Shape retrieval and geometric filtering are also investigated by taking into account the geometric properties of the model.     

Parallel <Emphasis Type="Italic">LL</Emphasis> parsing

A deterministic parallel LL parsing algorithm is presented. The algorithm is based on a transformation from a parsing problem to parallel reduction. First, a nondeterministic version of a parallel LL parser is introduced. Then, it is transformed into the deterministic version—the LLP parser. The deterministic LLP(q,k) parser uses two kinds of information to select the next operation — a lookahead string of length up to k symbols and a lookback string of length up to q symbols. Deterministic parsing is available for LLP grammars, a subclass of LL grammars. Since the presented deterministic and nondeterministic parallel parsers are both based on parallel reduction, they are suitable for most parallel architectures.     

<Emphasis Type="Italic">Post-PC-Ära</Emphasis>

Ohne Zusammenfassung     

The <Emphasis Type="Italic">POINT</Emphasis> approach to represent <Emphasis Type="Italic">now</Emphasis> in bitemporal databases

Most modern database applications involve a significant amount of time dependent data and a significant portion of this data is now-relative. Now-relative data are a natural and meaningful part of every temporal database as well as being the focus of most queries. Previous studies indicate that the choice of the representation of now significantly influences the efficiency of accessing bitemporal data. In this paper we propose and experimentally evaluate a novel approach to represent now that we termed the POINT approach, in which now-relative facts are represented as points on the transaction-time and/or valid-time line. Furthermore, in the POINT approach we propose a logical query transformation that relies on the above representation and on the geometry features of spatial access methods. Such a logical query transformation enables off-the-shelf spatial indexes to be used. We empirically prove that the POINT approach is efficient on now-relative bitemporal data, outperforming the maximum timestamp approach that has been proven to the best approach to now-relative data in the literature, independently of the indexing methodology (B ⁺- tree vs R ^*- tree) being used. Specifically, if spatial indexing is used, the POINT approach outperforms the maximum timestamp approach to the extent of factor more than 10, both in number of disk accesses and CPU usage.     

3D virtual mosaics: <Emphasis Type="Italic">Opus Palladium</Emphasis> and <Emphasis Type="Italic">mixed</Emphasis> styles

One of the oldest art forms, mosaics are built by careful selection and placement of small pieces called tiles. Although 2D mosaics have attracted attention in computer graphics research, 3D virtual mosaic sculptures are less common. In this work, we present a method to simulate mosaic sculptures using tiles with irregular shapes, a method known by mosaicists as Opus Palladium, or simply “crazy paving,” due to the inherent freedom of mixing the tiles. In order to add expressiveness and emphasize some features, artists distribute the tiles following a high-level design over the shape. We use Voronoi polygons to represent the tiles computed from a distribution of points on the surface of the 3D object. We also address the simulation of mixed mosaics, where both irregular and squared-shape tiles are used on the same object. Previous works on such surface mosaics have used only square-shaped tiles, with fixed or variable size. Special mosaic-like effects are obtained with the help from texture maps, which control the high-level design of the tile distribution.     

Nonblocking <Emphasis Type="Italic">k</Emphasis>-Compare-Single-Swap

The current literature offers two extremes of nonblocking software synchronization support for concurrent data structure design: intricate designs of specific structures based on single-location operations such as compare-and-swap (CAS), and general-purpose multilocation transactional memory implementations. While the former are sometimes efficient, they are invariably hard to extend and generalize. The latter are flexible and general, but costly. This paper aims at a middle ground: reasonably efficient multilocation operations that are general enough to reduce the design difficulties of algorithms based on CAS alone. We present an obstruction-free implementation of an atomic k -location-compare single-location-swap (KCSS) operation. KCSS allows for simple nonblocking manipulation of linked data structures by overcoming the key algorithmic difficulty in their design: making sure that while a pointer is being manipulated, neighboring parts of the data structure remain unchanged. Our algorithm is efficient in the common uncontended case: A successful k-location KCSS operation requires only two CAS operations, two stores, and 2k noncached loads when there is no contention. We therefore believe our results lend themselves to efficient and flexible nonblocking manipulation of list-based data structures in today’s architectures. A preliminary version of this paper appeared in the Proceedings of the Fifteenth Annual ACM Symposium on Parallel Algorithms and Architectures, pages 314–323, San Diego, California, USA, 2003.     

<Emphasis Type="Italic">O</Emphasis>(log*<Emphasis Type="Italic">n</Emphasis>) algorithms on a Sum-CRCW PRAM

We present work- and cost-optimal O(log*n) algorithms for prefix sums and linear integer sorting on a Sum-CRCW PRAM.     

Estimation of a Local Lipschitz Constant of the <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">q</Emphasis></Subscript>-Entropy

A method for estimating a Lipschitz constant of the entropy operator of the Boltzmann type is suggested. Examples of the use of the obtained estimates in problems for restoring images by projections are given.__________Translated from Avtomatika i Telemekhanika, No. 7, 2005, pp. 54–65.Original Russian Text Copyright © 2005 by Popkov, Rublev.This work was supported by the Program “Branch of Information Technologies and Computer Systems” and the Russian Foundation for Basic Research, project no. 02-01-00198a.     

Qualitative analysis of dynamic systems with the <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">q</Emphasis></Subscript> entropy operator

The method is suggested for the investigation of the existence, uniqueness, and localization of singular points of the DSEO class under consideration. The stability conditions are found “in the small” and “in the large.” Examples of the use of the obtained conditions are given.     

<Emphasis Type="Italic">Ontologie(n)</Emphasis>

Ontologie ist ein überlieferter Begriff aus der Philosophie und steht dort für die Lehre vom Sein – genauer: von den M?glichkeiten und Bedingungen des Seienden –, ist also eng verwandt mit der Erkenntnistheorie, die sich mit den M?glichkeiten und Grenzen menschlichen Wahrnehmens und Erkennens auseinander setzt. Vorschl?ge an Prof. Dr. Frank <puppe@informatik.uni-wuerzburg.de> oder Dieter Steinbauer <dieter.steinbauer@schufa.de> Alle „Aktuellen Schlagw?rter” seit 1988 finden Sie unter www.ai-wuerzburg.de/as     

On one transformation of Steiner quadruple systems <Emphasis Type="Italic">S</Emphasis>(<Emphasis Type="Italic">υ</Emphasis>, 4, 3)

A transformation of Steiner quadruple systems S(υ, 4, 3) is introduced. For a given system, it allows to construct new systems of the same order, which can be nonisomorphic to the given one. The structure of Steiner systems S(υ, 4, 3) is considered. There are two different types of such systems, namely, induced and singular systems. Induced systems of 2-rank r can be constructed by the introduced transformation of Steiner systems of 2-rank r − 1 or less. A sufficient condition for a Steiner system S(υ, 4, 3) to be induced is obtained.     

Stochastic <Emphasis Type="Italic">Ceteris Paribus</Emphasis> Simulations

Common random numbers (CRN) is a general variance reducing technique for comparing stochastic models via simulations. By inducing positive correlation between different simulations, CRN are likely to reduce the experimental or sampling variance of the difference between the simulations. However, in this paper my motivation for and interpretations of CRN go beyond the statistical design of a simulation experiment, and into the core of economic and econometric reasoning. In a counterfactual-, scenario- or policy analysis based on stochastic simulation, CRN implement the qualifier in partial analysis known as the ceteris paribus clause. In addition, CRN are consistent with the requirement of super exogeneity for valid policy analysis.