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Number of results: 108
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Abstract

The problem that this paper investigates, namely, optimization of overlay computing systems, follows naturally from growing need for effective processing and consequently, fast development of various distributed systems. We consider an overlay-based computing system, i.e., a virtual computing system is deployed on the top of an existing physical network (e.g., Internet) providing connectivity between computing nodes. The main motivation behind the overlay concept is simple provision of network functionalities (e.g., diversity, flexibility, manageability) in a relatively cost-effective way as well as regardless of physical and logical structure of underlying networks. The workflow of tasks processed in the computing system assumes that there are many sources of input data and many destinations of output data, i.e., many-to-many transmissions are used in the system. The addressed optimization problem is formulatedin the form of an ILP (Integer Linear Programing) model. Since the model is computationally demanding and NP-complete, besides the branch-and-bound algorithm included in the CPLEX solver, we propose additional cut inequalities. Moreover, we present and test two effective heuristic algorithms: tabu search and greedy. Both methods yield satisfactory results close to optimal.
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Authors and Affiliations

Krzysztof Walkowiak
Andrzej Kasprzak
Karol Andrusieczko
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Abstract

In this paper we show how formal computer science concepts—such as encoding, algorithm or computability—can be interpreted philosophically, including ontologically and epistemologically. Such interpretations lead to questions and problems, the working solutions of which constitute some form of pre-philosophical worldview. In this work we focus on questions inspired by the IT distinction between digitality and analogicity, which has its mathematical origin in the mathematical distinction between discreteness and continuity. These include the following questions: 1) Is the deep structure of physical reality digital or analog, 2) does the human mind resemble a more digital or analog computational system, 3) does the answer to the second question give us a cognitively fruitful insight into the cognitive limitations of the mind? As a particularly important basis for the above questions, we consider the fact that the computational power (i.e., the range of solvable problems) of some types of analog computations is greater than that of digital computations.

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Authors and Affiliations

Paweł Stacewicz
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Abstract

We address one of the weaknesses of the RSA ciphering systems i.e. the existence of the private keys that are relatively easy to compromise by the attacker. The problem can be mitigated by the Internet services providers, but it requires some computational effort. We propose the proof of concept of the GPGPU-accelerated system that can help detect and eliminate users’ weak keys. We have proposed the algorithms and developed the GPU-optimised program code that is now publicly available and substantially outperforms the tested CPU processor. The source code of the OpenSSL library was adapted for GPGPU, and the resulting code can perform both on the GPU and CPU processors. Additionally, we present the solution how to map a triangular grid into the GPU rectangular grid – the basic dilemma in many problems that concern pair-wise analysis for the set of elements. Also, the comparison of two data caching methods on GPGPU leads to the interesting general conclusions. We present the results of the experiments of the performance analysis of the selected algorithms for the various RSA key length, configurations of GPU grid, and size of the tested key set.

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Authors and Affiliations

Przemysław Karbownik
Paweł Russek
Kazimierz Wiatr
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Abstract

A Computational Intelligence (CI) approach is one of the main trending and potent data dealing out and processing instruments to unravel and resolve difficult and hard reliability crisis and it takes an important position in intelligent reliability analysis and management of data. Nevertheless, just few little broad reviews have recapitulated the current attempts of Computational Intelligence (CI) in reliability assessment in power systems. There are many methods in reliability assessment with the aim to prolong the life cycles of a system, to maximize profit and predict the life cycle of assets or systems within an organization especially in electric power distribution systems. Sustaining an uninterrupted electrical energy supply is a pointer of affluence and nationwide growth. The general background of reliability assessment in power system distribution using computational intelligence, some computational intelligence techniques, reliability engineering, literature reviews, theoretical or conceptual frameworks, methods of reliability assessment and conclusions was discussed. The anticipated and proposed technique has the aptitude to significantly reduce the needed period for reliability investigation in distribution networks because the distribution network needs an algorithm that can evaluate, assess, measure and update the reliability indices and system performance within a short time. It can also manage outages data on assets and on the entire system for quick and rapid decisions making as well as can prevent catastrophic failures. Those listed above would be taken care of if the proposed method is utilized. This overview or review may be deemed as valuable assistance for anybody doing research.
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Authors and Affiliations

Elijah Adebayo Olajuyin
1
ORCID: ORCID
Paul Kehinde Olulope
2
Emmanuel Taiwo Fasina
2

  1. Bamidele Olumilua University of Education, Science and Technology, Ikere Ekiti, Nigeria
  2. Ekiti State University, Ado Ekiti, Nigeria
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Abstract

The paper presents functionality and operation results of a system for creating dynamic maps of acoustic noise employing the PL-Grid infrastructure extended with a distributed sensor network. The work presented provides a demonstration of the services being prepared within the PLGrid Plus project for measuring, modeling and rendering data related to noise level distribution in city agglomerations. Specific computational environments, the so-called domain grids, are developed in the mentioned project. For particular domain grids, specialized IT solutions are prepared, i.e. software implementation and hardware (infrastructure adaptation), dedicated for particular researcher groups demands, including acoustics (the domain grid “Acoustics”). The infrastructure and the software developed can be utilized mainly for research and education purposes, however it can also help in urban planning. The engineered software is intended for creating maps of noise threat for road, railways and industrial sources. Integration of the software services with the distributed sensor network enables automatic updating noise maps for a specific time period. The unique feature of the developed software is a possibility of evaluating auditory effects which are caused by the exposure to excessive noise. The estimation of auditory effects is based on calculated noise levels in a given exposure period. The outcomes of this research study are presented in a form of the cumulative noise dose and the characteristics of the temporary threshold shift.
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Authors and Affiliations

Bożena Kostek
Andrzej Czyżewski
Józef Kotus
Maciej Szczodrak
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Abstract

Confidential algorithm for the approximate graph vertex covering problem is presented in this article. It can preserve privacy of data at every stage of the computation, which is very important in context of cloud computing. Security of our solution is based on fully homomorphic encryption scheme. The time complexity and the security aspects of considered algorithm are described.
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Authors and Affiliations

Daniel Waszkiewicz
Aleksandra Horubała
Piotr Sapiecha
Michał Andrzejczak
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Abstract

Mobile devices have become an integral part of our life and provide dozens of useful services to their users. However, usability of mobile devices is hindered by battery lifetime. Energy conservation can extend battery lifetime, however, any energy management policy requires accurate prediction of energy consumption, which is impossible without reliable energy measurement and estimation methods and tools. We present an analysis of the energy measurement methodologies and describe the implementations of the internal (profiling) software (proprietary, custom) and external software-based (Java API, Sensor API, GSM AT) energy measurement methodologies. The methods are applied to measure energy consumption on a variety of mobile devices (laptop PC, PDA, smart phone). A case study of measuring energy consumption on a mobile computer using 3DMark06 benchmarking software is presented

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Authors and Affiliations

Robertas Damaševičius
Vytautas Štuikys
Jevgenijus Toldinas
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Abstract

This paper concerns measurement procedures on an emotion monitoring stand designed for tracking human emotions in the Human-Computer Interaction with physiological characteristics. The paper addresses the key problem of physiological measurements being disturbed by a motion typical for human-computer interaction such as keyboard typing or mouse movements. An original experiment is described, that aimed at practical evaluation of measurement procedures performed at the emotion monitoring stand constructed at GUT. Different locations of sensors were considered and evaluated for suitability and measurement precision in the Human- Computer Interaction monitoring. Alternative locations (ear lobes and forearms) for skin conductance, blood volume pulse and temperature sensors were proposed and verified. Alternative locations proved correlation with traditional locations as well as lower sensitiveness to movements like typing or mouse moving, therefore they can make a better solution for monitoring the Human-Computer Interaction.

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Authors and Affiliations

Agnieszka Landowska
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Abstract

Some materials-related microstructural problems calculated using the phase-field method are presented. It is well known that the phase field method requires mesh resolution of a diffuse interface. This makes the use of mesh adaptivity essential especially for fast evolving interfaces and other transient problems. Complex problems in 3D are also computationally challenging so that parallel computations are considered necessary. In this paper, a parallel adaptive finite element scheme is proposed. The scheme keeps the level of node and edge for 2D and level of node and face for 3D instead of the complete history of refinements to facilitate derefinement. The information is local and exchange of information is minimized and also less memory is used. The parallel adaptive algorithms that run on distributed memory machines are implemented in the numerical simulation of dendritic growth and capillary-driven flows.

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Authors and Affiliations

M. Do-Quang
W. Villanueva
I. Singer-Loginova
G. Amberg
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Abstract

The computational intelligence tool has major contribution to analyse the properties of materials without much experimentation. The B4C particles are used to improve the quality of the strength of materials. With respect to the percentage of these particles used in the micro and nano, composites may fix the mechanical properties. The different combinations of input parameters determine the characteristics of raw materials. The load, content of B4C particles with 0%, 2%, 4%, 6%, 8% and 10% will determine the wear behaviour like CoF, wear rate etc. The properties of materials like stress, strain, % of elongation and impact energy are studied. The temperature based CoF and wear rate is analysed. The temperature may vary between 30°C, 100°C and 200°C. In addition, the CoF and wear rate of materials are predicted with respect to load, weight % of B4C and nano hexagonal boron nitride %. The intelligent tools like Neural Networks (BPNN, RBNN, FL and Decision tree) are applied to analyse these characteristics of micro / nano composites with the inclusion of B4C particles and nano hBN % without physically conducting the experiments in the Lab. The material properties will be classified with respect to the range of input parameters using the computational model.

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Authors and Affiliations

P. Radha
N. Selvakumar
R. Harichandran
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Abstract

Parallel computers are becoming more available. The natural way to improve computational efficiency of multibody simulations seems to be parallel processing. Within this work we are trying to estimate the efficiency of parallel computations performed using one of the commercial multibody solver. First, the short theoretical outline is presented to give the overview of modeling issues in multibody dynamics. Next, the experimental part is demonstrated. The series of dynamics analyses are carried out. The test mechanisms with variable number of bodies are used to gather the performance results of the solver. The obtained data allow for estimating the number of bodies which are sufficient to gain benefits from parallel computing as well as their level. The parallel processing profits are taken into account in the case of contact forces present in the system. The performance benefits are indicated, when the multilink belt chain is simulated, in which contact forces are included in the model.

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Authors and Affiliations

Paweł Malczyk
Janusz Frączek
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Abstract

Green spaces are an integral element of urban structures. They are not only a place of rest for their users, but also positively affect their well-being and health. The eff ect of these spaces, is the better, the smoother they create larger urban layout – stings of greenery. The introduction of urban greenery can and should be one of the basic elements of revitalization. Often, however, greenery is designed without multi-aspect analysis, enabling understanding of conditions and the use of existing potential in a given place. The use of computational design in conjunction with the use of generally available databases, such as numerical SRTM terrain models, publicly available OSM map database and EPW meteorological data, allows for the design of space in a more comprehensive way. These design methods allow better matching of the greenery design in a given area to specific architectural, urban and environmental conditions.

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Authors and Affiliations

Lucyna Nyka
Jan Cudzik
Kacper Radziszewski
Dominik Sędzicki
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Abstract

Half a century ago two papers were published, related to generalized inverses of cracovians by two different authors, in chronological order, respectively by Jean Dommanget and by Helmut Moritz. Both independently developed papers demonstrated new theorems, however, certain similarity between them appeared. Helmut Moritz having recognized that situation, promised to mention it later in one of his published papers. This has never been done, so the author of the present paper gives some details about the situation and claims his paternity.
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Authors and Affiliations

Jean Dommanget
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Abstract

Computational modeling plays an important role in the methodology of contemporary science. The epistemological role of modeling and simulations leads to questions about a possible use of this method in philosophy. Attempts to use some mathematical tools to formulate philosophical concepts trace back to Spinoza and Newton. Newtonian natural philosophy became an example of successful use of mathematical thinking to describe the fundamental level of nature. Newton’s approach has initiated a new scientific field of research in physics and at the same time his system has become a source of new philosophical considerations about physical reality. According to Michael Heller, some physical theories may be treated as the formalizations of philosophical conceptions. Computational modeling may be an extension of this idea; this is what I would like to present in the article. I also consider computational modeling in philosophy as a source of new philosophical metaphors; this idea has been proposed in David J. Bolter’s conception of defining technology. The consideration leads to the following conclusion: In the methodology of philosophy significant changes have been taking place; the new approach do not make traditional methods obsolete, it is rather a new analytical tools for philosophy and a source of inspiring metaphors.

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Authors and Affiliations

Paweł Polak

Authors and Affiliations

Piotr Karwat
1

  1. Department of Ultrasound, Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
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Abstract

Disk motors are characterized by the axial direction of main magnetic flux and the variable length of the magnetic flux path along varying stator/rotor radii. This is why it is generally accepted that reliable electromagnetic calculations for such machines should be carried out using the FEM for 3D models. The 3D approach makes it possible to take into account an entire spectrum of different effects. Such computational analysis is very time-consuming, this is in particular true for machines with one magnetic axis only. An alternate computational method based on a 2D FEM model of a cylindrical motor is proposed in the paper. The obtained calculation results have been verified by means of lab test results for a physical model. The proposed method leads to a significant decrease of computational time, i.e. the decrease of iterative search for the most advantageous design.

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Authors and Affiliations

Tomasz Wolnik
ORCID: ORCID
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Abstract

In this article we present a procedure that allows to synthesize optimal circuit representing any reversible function within reasonable size limits. The procedure allows to choose either the NCT or the MCT gate set and specify any number of ancillary qubits to be used in the circuit. We will explore efficacy of this procedure by synthesizing various sources of nonlinearity used in contemporary symmetric ciphers and draw conclusions about properties of those transformations in quantum setting. In particular we will try to synthesize optimal circuit representing ASCON cipher SBOX which recently won NIST competition for Lightweight Cryptography standard.
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Authors and Affiliations

Adam Jagielski
1

  1. Military University of Technology in Warsaw, Poland
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Abstract

Computational intelligence (CI) can adopt/optimize important principles in the workflow of 3D printing. This article aims to examine to what extent the current possibilities for using CI in the development of 3D printing and reverse engineering are being used, and where there are still reserves in this area. Methodology: A literature review is followed by own research on CI-based solutions. Results: Two ANNs solving the most common problems are presented. Conclusions: CI can effectively support 3D printing and reverse engineering especially during the transition to Industry 4.0. Wider implementation of CI solutions can accelerate and integrate the development of innovative technologies based on 3D scanning, 3D printing, and reverse engineering. Analyzing data, gathering experience, and transforming it into knowledge can be done faster and more efficiently, but requires a conscious application and proper targeting.
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Authors and Affiliations

Izabela Rojek
1
ORCID: ORCID
Dariusz Mikołajewski
1
ORCID: ORCID
Joanna Nowak
2
ORCID: ORCID
Zbigniew Szczepański
2
ORCID: ORCID
Marek Macko
2
ORCID: ORCID

  1. Institute of Computer Science, Kazimierz Wielki University, Bydgoszcz, Poland
  2. Faculty of Mechatronics, Kazimierz Wielki University, Bydgoszcz, Poland
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Abstract

This paper presents a numerical analysis of the thermal-flow characteristics for a laminar flow inside a rectangular microchannel. The flow of water through channels with thin obstacles mounted on opposite walls was analyzed. The studies were conducted with a low Reynolds number (from 20 to 200). Different heights of rectangular obstacles were analyzed to see if geometrical factors influence fluid flow and heat exchange in the microchannel. Despite of the fact that the use of thin obstacles in the microchannels leads to an increase in the pressure drop, the increase in the height of the obstacles favors a significant intensification of heat exchange with the maximum thermal gain factor of 1.9 for the obstacle height coefficient h/H=0.5, which could be acceptable for practical application.
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Authors and Affiliations

Małgorzata Kmiotek
1
ORCID: ORCID
Robert Smusz
1
ORCID: ORCID

  1. Rzeszow University of Technology, The Faculty of Mechanical Engineering and Aeronautics, Rzeszow, Poland
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Abstract

This paper presents a new type of underactuated ground mobile robot called Caster Car. The platform consists of a front-driven and steered wheel and two uncontrolled rear caster wheels. The Caster Car model presented can be an interesting alternative for mobile robots that connects dynamic properties of hovercrafts and classical 4-wheeled cars. Underactuated properties of the Caster Car cause that classical proportional-derivative feedback control give the ability to affect only selected configuration variables. Three mathematical models of the Caster Car are proposed: a dynamic model with free-moving casters, a dynamic model with blocked casters, and a simplified hovercraft description. Models were tested during tracking tasks with demanding trajectory using selective and full-state control. This full state control was based on the computed torque technique with the pseudoinverse operation and proportional-derivative feedback. It gives the ability to suppress unstable behaviors of uncontrolled orientation but in cost of overall effect (higher position errors).
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Authors and Affiliations

Sebastian Korczak
1
ORCID: ORCID

  1. Warsaw University of Technology, ul. Narbutta84, 02-524 Warsaw, Poland
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Abstract

In the paper, a noise map service designated for the user interested in environmental noise is presented. Noise prediction algorithm and source model, developed for creating acoustic maps, are working in the cloud computing environment. In the study, issues related to the noise modelling of sound propagation in urban spaces are discussed with a particular focus on traffic noise. Examples of results obtained through a web application created for that purpose are shown. In addition, these are compared to results obtained from the commercial software simulations based on two road noise prediction models. Moreover, the computing performance of the developed application is investigated and analyzed. In the paper, a flowchart simulating the operation of the noise web-based service is presented showing that the created application is easy to use even for people with little experience in computer technology.
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Authors and Affiliations

Karolina Marciniuk
Bożena Kostek
Maciej Szczodrak

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