Reducts of propositional theories,satisfiability relations,and generalizations of semantics of logic programs

Over the years, the stable-model semantics has gained a position of the correct (two-valued) interpretation of default negation in programs. However, for programs with aggregates (constraints), the stable-model semantics, in its broadly accepted generalization stemming from the work by Pearce, Ferraris and Lifschitz, has a competitor: the semantics proposed by Faber, Leone and Pfeifer, which seems to be essentially different. Our goal is to explain the relationship between the two semantics. Pearce, Ferraris and Lifschitz's extension of the stable-model semantics is best viewed in the setting of arbitrary propositional theories. We propose here an extension of the Faber–Leone–Pfeifer semantics, or FLP semantics, for short, to the full propositional language, which reveals both common threads and differences between the FLP and stable-model semantics. We use our characterizations of FLP-stable models to derive corresponding results on strong equivalence and on normal forms of theories under the FLP semantics. We apply a similar approach to define supported models for arbitrary propositional theories, and to study their properties.     

When cognitive exertion does not yield cognitive gain: Toward an informational explanation of learned helplessness.

This study tested a new information-processing explanation of learned helplessness that proposes that an uncontrollable situation produces helplessness symptoms because it is a source of inconsistent, self-contradictory task information during problem-solving attempts. The flow of such information makes hypothesis-testing activity futile. Prolonged and inefficient activity of this kind leads in turn to the emergence of a state of cognitive exhaustion, with accompanying performance deficits. In 3 experiments, Ss underwent informational helplessness training (IHT): They were sequentially exposed to inconsistent task information during discrimination problems. As predicted, IHT was associated with subjective symptoms of irreducible uncertainty and resulted in (a) performance deterioration on subsequent avoidance learning, (b) heightened negative mood, and (c) subjective symptoms of cognitive exhaustion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cylindrical banyan multicomputer: A reconfigurable systolic architecture

A new reconfigurable systolic multicomputer architecture is presented. The proposed architecture, called the Cylindrical Banyan Multicomputer (CBM), is based on the structure of a modified banyan network where every node of the network graph is composed of an application processor, a local memory and a communication processor, and network's inputs and outputs are merged (fused). The CBM has one of the lowest (cost) X (delay) among known multicomputer architectures based on regular networks. It is shown that a variety of computation structures such as pipelines, rings, and trees may be constructed and reconfigured in an optimal or a nearby optimal way on the CBM architecture, and that various basic algorithms can be executed very efficiently in a systolic manner. It is also shown that the CBM is an easily diagnosable and fault-tolerant system.     

Large-scale multimedia content delivery over optical networks for interactive TV services

iTVP is a system built for delivery of live TV programming, video-on-demand and audio-on-demand with interactive access over IP networks. It has a nationwide range and is designed to provide service to a high number of concurrent users. Hence, scalability is one of the most important issues. In this paper we described how scalability is achieved in a two-level hierarchical architecture of the delivery system. We present the principles of content caching mechanisms and the management of the resulting distributed content repository. The system is implemented and currently operates in a test installation. Although the range of the test system operations is limited, as far as the number of users and the size of the content repository is concerned, the experience gained with iTVP so far provides an insight into the expected prototype performance. We present a system performance evaluation and describe the experience gained during the iGrid demonstration.     

Estimation of complex multimodal motion: an approach based on robust statistics and Hough transform

An application of robust statistics in a Hough transform based motion estimation approach is presented. The algorithm is developed and experiments are performed, proving its superior performance in terms of estimate accuracy, convergence, robustness and better segmentation. Comparative results with standard methods are also included.     

Model of Desulphurization of Steel Melts in Ladles – Deoxidation and Slag Formers Calculation

The authors present their own model applicable for effective desulphurization of steel by ladle treatment. The model is based on a thermodynamic approach (equilibrium data) and technological data (correction factors). It consists of two parts. In the first part the authors present the formulae derived for estimation of the additions of deoxidation agents which ensure sufficiently low oxygen level prior to the desulphurization process, while the other part gives a qualitative and quantitative selection of slag formers to achieve low final levels of sulphur in steel. For the deoxidation process two variants were considered: (i) with Al only (for low silicon steels) or (ii) Al‐Si (for silicon steels) as deoxidizers. For the desulphurization process three variants were assumed as to ladle slag composition: (i) slag consisting of a fraction of furnace slag, lime addition and deoxidation products, (ii) slag made of synthetic CaO–Al₂O₃ and (iii) slag based on lime and fluorspar. The model formulae for desulphurization were derived using the sulphide capacity concept which relies on the optical basicity. In addition, rough estimates of the slag liquidus temperatures are given. A numeric example of the model application and the model algorithm (appendix) are enclosed.     

Computer Modelling of Deformation of Steel Samples with Mushy Zone

The integrated casting and rolling of steel plates in processes such as Inline Strip Production or Arvedi Steel Technology is the latest and very efficient way of hot strip production. The numerical modelling is very helpful in developing a “know how” theory for the mentioned processes. One of the most important relationships having crucial influence on the metal flow path is the strain‐stress curve. The inverse method, which is usually the only method of calculating a real strain‐stress relationship, needs a good mathematical model describing the plastic behaviour of the material. The model presented in the current paper fills the gap in modelling of plastic deformation of semi‐solid materials. On the other hand, the mathematical modelling should be closely related to experiments. The well known machine allowing tests in the discussed temperature range is the GLEEBLE thermo‐mechanical simulator. However, carrying out experiments with steel deformation in the semi‐solid state using this machine is very expensive. Therefore, application of a dedicated computer simulation system is strictly required. Inverse analysis and appropriate modelling of the testing procedure makes tests possible, first of all, but it also results in lowering testing cost. The newest version of the Def_Semi_Solid is a unique FEM system supporting tests at extra high temperature.     

Application of generalized dynamic neural networks to biomedical data

This paper reviews the application of continuous recurrent neural networks with time-varying weights to pattern recognition tasks in medicine. A general learning algorithm based on Pontryagin's maximum principle is recapitulated, and possibilities of improving the generalization capabilities of these networks are given. The effectiveness of the methods is demonstrated by three different real-world examples taken from the fields of anesthesiology, orthopedics, and radiology.     

Investigations of the Dephosphorization of Liquid Iron Solution Containing Chromium and Nickel

The most up-to-date trends in stainless steel production??aiming at the reduction of production costs??consist of the substitution of steel scrap by hot metal, coming from the reduction of iron-chromium ores. This process requires a more extensive dephosphorization. The dephosphorization process, when applied to chromium steels, requires slag with high dephosphorization properties, as either chromium or chromium oxide entering the slag decreases distinctly the efficiency of the process. The results of laboratory investigations on the dephosphorization of liquid iron solutions containing chromium and nickel are presented. In particular, the study was focused on the selection of the optimal slag composition and the way the slag should be added. The slags based on calcium and fluorite with cryolite additions were considered. It was shown that the variables with the greatest impact on the dephosphorization process include chromium and nickel levels, temperature, and slag basicity. A statistical analysis was performed and regression equations were set. The results may be of use for the design of new methods of production of high-chromium steels.