Compact Representation of Value Function in Partially Observable Stochastic Games

Value methods for solving stochastic games with partial observability model the uncertainty about states of the game as a probability distribution over possible states. The dimension of this belief space is the number of states. For many practical problems, for example in security, there are exponentially many possible states which causes an insufficient scalability of algorithms for real-world problems. To this end, we propose an abstraction technique that addresses this issue of the curse of dimensionality by projecting high-dimensional beliefs to characteristic vectors of significantly lower dimension (e.g., marginal probabilities). Our two main contributions are (1) novel compact representation of the uncertainty in partially observable stochastic games and (2) novel algorithm based on this compact representation that is based on existing state-of-the-art algorithms for solving stochastic games with partial observability. Experimental evaluation confirms that the new algorithm over the compact representation dramatically increases the scalability compared to the state of the art

ON TUNING THE DYNAMIC LOAD BALANCING FEM FRAMEWORK

Developments in computer hardware are currently bringing new opportunities for numerical modelling. The current trend in technology is parallel processing making use of multiple processing units simultaneously to solve a given problem. This paper deals with exploring the parallel dynamic load balancing framework implemented in the finite element software. This framework is based on a domain decomposition paradigm for distributed memory model. The paper describes the improved technique to determine the actual processor weights related to performance of individual processing units. The load recovery consisting in mesh (re)partitioning is based on actual processor weights. The (re)partitioning process has to be performed during the simulation and whenever the load imbalance is significant. The performance of the proposed technique is tested on the benchmark problem and discussed

PARALLELIZATION OF ASSEMBLY OPERATION IN FINITE ELEMENT METHOD

The efficient codes can take an advantage of multiple threads and/or processing nodes to partition a work that can be processed concurrently. This can reduce the overall run-time or make the solution of a large problem feasible. This paper deals with evaluation of different parallelization strategies of assembly operations for global vectors and matrices, which are one of the critical operations in any finite element software. Different assembly strategies for systems with a shared memory model are proposed and evaluated, using Open Multi-Processing (OpenMP), Portable Operating System Interface (POSIX), and C++11 Threads. The considered strategies are based on simple synchronization directives, various block locking algorithms and, finally, on smart locking free processing based on a colouring algorithm. The different strategies were implemented in a free finite element code with object-oriented architecture OOFEM [1]

The effect of gear geometry on the thickness of tooth face hardened layer

This article describes the effect of the geometrical parameters of the standard involute and non-standard convex-concave (C-C) gearing on the thickness of the hardened layer. The thickness of hardened layer is important from the aspect of wear on gearing. In case of involute gearing is the thickness of the hardened layer defined by various authors, what is on the other hand determinated also by the standard STN 01 4686-5. In case of C-C gearing there are not available any standards, and therefore it is possible to determine the thickness of the hardened layer only by the means of modern simulation methods.В статье описывается влияние геометрических параметров стандартных эвольвентных и нестандартных выпукло-вогнутых (CC) зубчатых передач до толщины упрочненного слоя. Толщина упрочненного слоя имеет важное значение для износа зуба. В случае с эвольвентной передачей толщина слоя определяется более авторами, и также использованием стандарта STN 01 4686-5. В случае нестандартных выпукло-вогнутых (C-C) зубчатых передач нет стандартов, поэтому можно определить толщину закаленного слоя только с использованием современных методов моделирования

PVD coating as a possibility to increase the load capacity of gearings to scuffing

In the article we describe the possibilities of increase of the contact load capacity of unhardened C-C toothed gear. The use of metal coatings proves to be one way. On the basis of a comparison of the individual methods of depositing the coating technology of PVD (physical vapour deposition) proves to be suitable application for the case of gearings. This technology is used for depositing the hard coatings. C-C toothed gear, coated with TiN, in interaction with ecological lubricant was experimentally verified with respect to scuffing on test stand by Niemann and compared to the hardened involvent gearing.Стаття знайомить з можливостями підвищення контактної несучої здатності незагартованого опукло-ввігнутого зубчастого зачеплення. Однією з можливостей є використання металевих покрить. На підставі порівнювання окремих методів нанесення покриття підхожим виявляється у випадку зубчастих передач технологія PVD (physical vapor deposition). Ця технологія використовується для нанесення твердого покриття. TiN покрита С-С зубчаста передача у взаємодії з обраними екологічними мастилами була експериментально провірена проти заїдання на стенді Німанна/Niemann/ та порівнювалася з загартованою евольвентою зубчастою передачею

Le visite canoniche della diocesi di Nitra

The canonical visitation became one of the most important instruments of the Tridentine renewal. This study presents the canonical visitations made in the Diocese of Nitra – examining their final reports that represent historical resources of great value. It offers a summary of all the visitations – both partial and comprehensive ones – since 1674, when the first visitation recorded in written form was made, up to the present day – describing their circumstances, ways of realization, as well as their findings. It analyzes the pattern and the structure of every final report. It also examines the feasibility of their investigation and other studies accomplished in the past. Finally, it offers the evaluation of the canonical visitations from the point of view of their contribution to the renewal of the diocese

Effect of tooth shape to size of contact stress noninvolute gearing

The article describes the effect of the tooth shape to the size of the contact stress. Using the geometrical parameters konex-concave gearing can change the tooth profile, which can be achieved by reducing the size of the contact stress. Important role played by reduced radii of curvature, which significantly affect to the size of these stress. Comparative two places around the beginning (point B) and end (point D) on the line of action.В статье описывается влияние формы зуба с размером контактного напряжения. В геометрических параметрах выпукло-вогнутой передачи можно изменить форму зубов, которая может быть достигнута за счет сокращения размеров контактных напряжений. Важную роль играет сокращение радиусов кривизны, которая существенно влияет на размер этих напряжений. Приравнивается два места вокруг самого начала (точка B) и конца (точка D) на линии зацепления, которые находится в непосредственной близости от этих точек представленых одно и двухпарным зацеплением

Можливості використання твердих тонких покриттів у HCR зачепленні, яке працює в екологічно чистому мастилі

The article describes the possibilities of application of hard thin coatings to a non-standard involute HCR gearing, made from 16MnCr5, working in interaction with ecological transmission oil OMV Biogear S150. Based on an analysis of their geometric characteristics and their differences from nonstandard C–C teeth, the possibilities of applying thin hard coatings to the side surface of the teeth are assessed. From the previous results obtained at the research center (UDTK sjF STU in Bratislava), the nitride TiALCN was applied and the article presents the results obtained on the Niemann´s stand for scuffing, from which it follows that due to the higher heights of the tooth addendum (hа = 1,2m) compared to the standard (hа = 1,0 m) and hence larger meridians, the greatest damage there was on an addendum of pinion.У статті описані можливості застосування твердих тонких покриттів до нестандартної евольвентної передачі HCR, яка виготовленна з матеріалу 16MnCr5 і працює в екологічно чистому трансмісійному мастилі OMV Biogear S150. На основі аналізу їх геометричних характеристик і відмінностей від нестандартного зубчастого зачеплення C–C оцінюються можливості нанесення тонких твердих покриттів на бічну поверхню зубів. З попередніх результатів, отриманих в дослідницькому центрі (UDTK sjF STU в Братиславі), застосований нітрид TiALCN і в статті представлені результати, отримані на стенді Ньюмана для зносу, з яких випливає, що через більшу висоту головки зуба (hа = 1,2m) порівняно зі стандартною (hа = 1,0m) і, відтак, великими меридіанами, найбільший знос був на голівці зуба шестерні

OPTIMAL ADDENDUM COEFFICIENTS OF CYLINDRICAL INVOLUTE GEARING FROM POINT OF VIEW ITS EFFICIENCY

The optimisation of gearboxes, namely of teethed wheels is still valid subject of scientific research. The development of software products for multiparametrical optimisation at Machine Engineering Faculty University of Technology Bratislava was concluded into successful solutions of arbitrary defined objective functions. In the article are given the results of teeth gears optimisation with involute gearing from point of view of its efficiency. The calculation included the complete geometrical and strength check of gearing according to DIN 3990 level B / ISO 6336 as the restriction conditions in original way.The optimisation of gearboxes, namely of teethed wheels is still valid subject of scientific research. The development of software products for multiparametrical optimisation at Machine Engineering Faculty University of Technology Bratislava was concluded into successful solutions of arbitrary defined objective functions. In the article are given the results of teeth gears optimisation with involute gearing from point of view of its efficiency. The calculation included the complete geometrical and strength check of gearing according to DIN 3990 level B / ISO 6336 as the restriction conditions in original way