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Abstract

Evolutionary computing and algorithms are well known tools of optimisation that are utilized for various areas of analogue electronic circuits design and diagnosis. This paper presents the possibility of using two evolutionary algorithms - genetic algorithm and evolutionary strategies - for the purpose of analogue circuits yield and cost optimisation. Terms: technologic and parametric yield are defined. Procedures of parametric yield optimisation, such as a design centring, a design tolerancing, a design centring with tolerancing, are introduced. Basics of genetic algorithm and evolutionary strategies are presented, differences between these two algorithms are highlighted, certain aspects of implementation are discussed. Effectiveness of both algorithms in parametric yield optimisation has been tested on several examples and results have been presented. A share of evolutionary algorithms computation cost in a total optimisation cost is analyzed.

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Authors and Affiliations

P. Jantos
J. Rutkowski
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Abstract

A new notion of a realization of transfer matrix of (P;Q; V)-cone-system for discrete-time linear systems is proposed. Necessary and sufficient conditions for the existence of the realizations are established. A procedure is proposed for computation of a realization of a given proper transfer matrix T(z) of (P;Q; V)-cone-system. It is shown that there exists a realization of T(z) of (P;Q; V)-cone-system if and only if there exists a positive realization of T(z) = V T(z)Q!1, where V;Q and P are non-singular matrices generating the cones V;Q and P respectively.

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Authors and Affiliations

T. Kaczorek
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Abstract

Material parameters identification by inverse analysis using finite element computations leads to the resolution of complex and time-consuming optimization problems. One way to deal with these complex problems is to use meta-models to limit the number of objective function computations. In this paper, the Efficient Global Optimization (EGO) algorithm is used. The EGO algorithm is applied to specific objective functions, which are representative of material parameters identification issues. Isotropic and anisotropic correlation functions are tested. For anisotropic correlation functions, it leads to a significant reduction of the computation time. Besides, they appear to be a good way to deal with the weak sensitivity of the parameters. In order to decrease the computation time, a parallel strategy is defined. It relies on a virtual enrichment of the meta-model, in order to compute q new objective functions in a parallel environment. Different methods of choosing the qnew objective functions are presented and compared. Speed-up tests show that Kriging Believer (KB) and minimum Constant Liar (CLmin) enrichments are suitable methods for this parallel EGO (EGO-p) algorithm. However, it must be noted that the most interesting speed-ups are observed for a small number of objective functions computed in parallel. Finally, the algorithm is successfully tested on a real parameters identification problem.

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Bibliography

[1] P.A. Prates, M.C Oliveira, and J.V. Fernandes. Identification of material parameters for thin sheets from single biaxial tensile test using a sequential inverse identification strategy. International Journal of Material Forming, 9:547–571, 2016. doi: 10.1007/s12289-015-1241-z.
[2] M. Gruber, N. Lebaal, S. Roth, N. Harb, P. Sterionow, and F. Peyraut. Parameter identification of hardening laws for bulk metal forming using experimental and numerical approach. International Journal of Material Forming, 9:21–33. doi: 10.1007/s12289-014-1196-5.
[3] R. Amaral, P. Teixeira, A.D. Santos, and J.C. de Sá. Assessment of different ductile damage models and experimental validation. International Journal of Material Forming, 11, 435–444, 2018. doi: 10.1007/s12289-017-1381-4.
[4] J. Nocedal and S. Wright. Numerical Optimization, 2nd ed. Springer-Verlag, New York, 2006.
[5] J.A. Nelder and R. Mead. A simplex method for function minimization. The Computer Journal, 7(4):308–313, 1965. doi: 10.1093/comjnl/7.4.308.
[6] K.Y. Lee and F.F. Yang. Optimal reactive power planning using evolutionalry algorithms: a comparative study for evolutionary programming, evolutionary strategy, genetic algorithm, and linear programming. IEEE Transactions on Power Systems, 13(1):101–108, 1998. doi: 10.1109/59.651620.
[7] N. Stander, K.J. Craig, H. Müllerschön, and R. Reichert. Material identification in structural optimization using response surfaces. Structural and Multidisciplinary Optimization, 29:93–102, 2005. doi: 10.1007/s00158-004-0476-y.
[8] M. Ageno, G. Bolzon, and G. Maier. An inverse analysis procedure for the material parameter identification of elastic- plastic free-standing foils. Structural and Multidisciplinary Optimization, 38:229–243, 2009. doi: 10.1007/s00158-008-0294-8.
[9] M. Abendroth and M. Kuna. Identification of ductile damage and fracture parameters from the small punch test using neural networks. Engineering Fracture Mechanics, 73(6):710–725, 2006. doi: 10.1016/j.engfracmech.2005.10.007.
[10] R. Franchi, A. Del Prete, and D. Umbrell. Inverse analysis procedure to determine flow stress and friction data for finite element modeling of machining. International Journal of Material Forming, 10:685–695, 2017. doi: 10.1007/s12289-016-1311-x.
[11] N. Souto, A. Andrade-Campos, and S. Thuillier. Mechanical design of a heterogeneous test for material parameters identification. International Journal of Material Forming, 10:353–367, 2017. doi: 10.1007/s12289-016-1284-9.
[12] M. Rackl, K.J. Hanley, and W.A. Günthner. Verification of an automated work flow for discrete element material parameter calibration. In: Li X., Feng Y., Mustoe G. (eds.), Proceedings of the 7th International Conference on Discrete Element Methods. DEM 2016, volume 188, pages 201–208. Springer, Singapore 2017. doi: 10.1007/978-981-10-1926-5_23.
[13] K. Levenberg. A method for the solution of certain non-linear problems in least squares. Quarterly of Applied Mathematics, 2(2):164–168, 1944.
[14] C. Richter, T. Rößler, G. Kunze, A. Katterfeld, and F. Will. Development of a standard calibration procedure for the DEM parameters of cohesionless bulk materials – Part II: Efficient optimization-based calibration. Powder Technology, 360:967–976, 2020. doi: 10.1016/j.powtec.2019.10.052.
[15] D.R. Jones, M. Schonlau, and W.J. Welch. Efficient global optimization of expensive black-box function. Journal of Global Optimization, 13:455–492, 1998. doi: 10.1023/A:1008306431147.
[16] M.T.M. Emmerich, K.C. Giannakoglou, and B. Naujoks. Single- and multi-objective evolutionary optimization assisted by gaussian random field metamodels. IEEE Transactions on Evolutionary Computation, 10(4):421–439, 2006. doi: 10.1109/TEVC.2005.859463.
[17] T.J. Santner, B.J. Williams, and W.I. Notz. The Design and Analysis of Computer Experiments. Springer, New York, 2018. doi: 10.1007/978-1-4939-8847-1.
[18] E. Brochu, V.M. Cora, and N. de Freitas. A tutorial on Bayesian optimization of expensive cost functions, with application to active user modeling and hierarchical reinforcement learning. Technical Report TR-2009-23, Department of Computer Science, University of British Columbia, Canada, November 2009.
[19] D. Ginsbourger, R. Riche, and L. Carraro. Kriging is well-suited to parallelize optimization. In Y. Tenne, Ch-K. Goh (eds.), Computational Intelligence in Expensive Optimization Problems, volume 2, pages 131–162, Springer-Verlag, Berlin, 2010.
[20] E. Roux and P.-O. Bouchard. Kriging metamodel global optimization of clinching joining processes accounting for ductile damage. Journal of Materials Processing Technology, 213(7):1038–1047, 2013. doi: 10.1016/j.jmatprotec.2013.01.018.
[21] E. Roux and P.-O. Bouchard. On the interest of using full field measurements in ductile damage model calibration. International Journal of Solids and Structures, 72:50–62, 2015. doi: 10.1016/j.ijsolstr.2015.07.011.
[22] J. Sacks, W.J. Welch, T.J. Mitchell, and H.P. Wynn. Design and analysis of computer experiments. Statistical Science, 4(4):409–423, 1989.
[23] K. Deb, S. Agrawal, A. Pratap, and T. Meyarivan. A fast elitist non-dominated sorting genetic algorithm for multi-objective optimization: NSGA-II. In: Schoenauer M. et al. (eds,), Parallel Problem Solving from Nature PPSN VI. PPSN 2000. Lecture Notes in Computer Science, volume 1917, pages 849–858. Springer, Berlin, Heidelberg, 2000. doi: 10.1007/3-540-45356-3_83.
[24] M. Hamdaoui, F.Z. Oujebbour, A. Habbal, P. Breitkopf, and P. Villon. Kriging surrogates for evolutionary multi-objective optimization of CPU intensive sheet metal forming applications. International Journal of Material Forming, 8:469–480, 2015. doi: 10.1007/s12289-014-1190-y.
[25] J.J. Droesbeke, M. Lejeune, and G. Saporta. Statistical Analysis of Spatial Data. Editions TECHNIP, 1997 (in French).
[26] C.E. Rasmussen and C.K.I. Williams. Gaussian Processes for Machine Learning. MIT Press, 2006.
[27] J.D. Martin and T.W. Simpson. Use of kriging models to approximate deterministic computer models. AIAA Journal, 43(4):853–863, 2005. doi: 10.2514/1.8650.
[28] J. Laurenceau and P. Sagaut. Building efficient response surface of aerodynamic function with kriging and cokriging. AIAA Journal, 46(2):498–507, 2008. doi: 10.2514/1.32308.
[29] D.R. Jones. A taxonomy of global optimization methods based on response surfaces. Journal of Global Optimization, 21:345–383, 2001. doi: 10.1023/A:1012771025575.
[30] V.A. Dirk and H.G. Beyer. A comparison of evolution strategies with other direct search methods in the presence of noise. Computational Optimization and Applications, 24:135–159, 2003. doi: 10.1023/A:1021810301763.
[31] J.A. Nelder and R. Mead. A simplex method for function minimization. The Computer Journal, 7(4):308–313, 1965. doi: 10.1093/comjnl/7.4.308.
[32] P.-O. Bouchard, J.-M. Gachet, and E. Roux. Ductile damage parameters identification for cold metal forming applications. AIP Conference Proceedings, 1353(1):47–52, 2011. doi: 10.1063/1.3589490.
[33] D. Huang, T.T. Allan, W.I. Notz, and N. Zeng. Global optimization of stochastic black-box systems via sequential kriging meta-models. Journal of Global Optimization, 34:441–466, 2006. doi: 10.1007/s10898-005-2454-3.
[34] H.H. Rosenbrock. An automatic method for finding the greatest or least value of a function. The Computer Journal, 3(3):175–184, 1960. doi: 10.1093/comjnl/3.3.175.
[35] M. Pillet. The Taguchi Method Experiment Plans. Les Edition d'Organisation, 2005 (in French).
[36] H. Digonnet, L. Silva, and T. Coupez. Cimlib: A Fully Parallel Application For Numerical Simulations Based On Components Assembly. AIP Conference Proceedings, 908:269–274, 2007. doi: 10.1063/1.2740823.
[37] P.-O. Bouchard, L. Bourgeon, S. Fayolle, and K. Mocellin. An enhanced Lemaitre model formulation for materials processing damage computation. International Journal of Material Forming, 4:299–315, 2011. doi: 10.1007/s12289-010-0996-5.
[38] E. Roux, M. Thonnerieux, and P.-O. Bouchard. Ductile damage material parameter identification: numerical investigation. In Proceedings of the Tenth International Conference on Computational Structures Technology, paper 135, Civil-Comp Press, 2010. doi: 10.4203/ccp.93.135.
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Authors and Affiliations

Emile Roux
1
Yannick Tillier
2
Salim Kraria
2
Pierre-Olivier Bouchard
2

  1. Université Savoie Mont-Blanc, SYMME, F-74000 Annecy, France.
  2. MINES ParisTech, PSL Research University, CEMEF-Centre de mise en forme des matériaux, CNRS UMR 7635, CS 10207 rue Claude Daunesse, 06904 Sophia Antipolis Cedex, France
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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

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

Quantum computers excel at tasks where classical computers falter – explains Prof. Artur Ekert from the Mathematical Institute at Oxford University and the National University of Singapore.
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Authors and Affiliations

Artur Ekert
1

  1. the Mathematical Institute at Oxford University and the National University of Singapore
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Abstract

This paper presents results of evolutionary minimisation of peak-to-peak value of a multi-tone signal. The signal is the sum of multiple tones (channels) with constant amplitudes and frequencies combined with variable phases. An exemplary application is emergency broadcasting using widely used analogue broadcasting techniques: citizens band (CB) or VHF FM commercial broadcasting. The work presented illustrates a relatively simple problem, which, however, is characterised by large combinatorial complexity, so direct (exhaustive) search becomes completely impractical. The process of minimisation is based on genetic algorithm (GA), which proves its usability for given problem. The final result is a significant reduction of peak-to-peak level of given multi-tone signal, demonstrated by three real-life examples.

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Authors and Affiliations

Ł. Chruszczyk
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Abstract

In the electromagnetic field simulation of modern servo drives, the computation of higher time and space harmonics is essential to predict torque pulsations, radial forces, ripple torques and cogging torque. Field computation by conformal map ping (CM) techniques is a time-effective method to compute the radial and tangential field components. In the standard CM approach, computational results of cogging torque simulations as well as overload operations observe deviations to nonlinear finite element (FE) simulations due to the neglection of slot leakage and saturation effects. This paper presents an extension of the classical CM. Additional CM parameters are computed from single finite element computations so as to consider both effects listed above in the model over a wide operation range of the electrical drive. The proposed approach is applied to a surface permanent magnet synchronous machine (SM-PMSM), and compared to numerical results obtained by finite element analysis (FEA). An accuracy similar to that of FE simulations is obtained with however the low computation time that is characteristic for analytical models.

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Authors and Affiliations

Martin Hafner
David Franck
Kay Hameyer
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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

In the realm of high-power LED applications, several critical concerns emerge, significantly impacting LED operational efficiency and reliability. Among these concerns, wire deformation during the LED encapsulation process poses a substantial threat to LED longevity. This research endeavors to investigate the influence of gold wire quantity on the LED encapsulation procedure. Leveraging ANSYS Fluent, our study employs the Volume of Fluid (VOF) technique along with a user-defined function (UDF) to model the deposition of epoxy materials onto the LED. Moreover, ANSYS Fluent is harnessed for a comprehensive analysis of fluid-structure interaction (FSI) phenomena that occur between the gold wire bonding and the epoxy materials. The FSI modeling allows us to indirectly quantify the stress exerted on the gold wire bonding during the encapsulation process. Our simulations encompass a range of gold wire quantities, spanning from 1 to 5, while a validation experiment is conducted to affirm the structural integrity of epoxy materials as per the simulation setup. Our findings reveal a direct correlation between increased epoxy material density and heightened wire deformation, stress levels, and strain distribution on the wire bonding. For EMC, which has the highest density, the maximum gold wire deformation, Von Mises stress, and strain distribution on the gold wire are 2.6616×10–8 mm, 0.00064 MPa, and 8.2019×10–9, respectively. Additionally, the simulations underscore that augmenting the number of gold wires exacerbates stress and strain distribution, assuming consistent epoxy material usage. The present study will contribute to the understanding of the mechanical aspects linked with LED encapsulation and present potential opportunities for improving manufacturing procedures and guiding future experimental attempts in this research domain.
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Authors and Affiliations

M.S. Abdul Azis
1
ORCID: ORCID
M.S. Rusdi
1
ORCID: ORCID
M.S. Zubir
1
Z. Embong
2
ORCID: ORCID
M. Nabiałek
3
ORCID: ORCID

  1. Universiti Sains Malaysia, School of Mechanical Engineering, Engineering Campus, 14300, Nibong Tebal, Penang, Malaysia
  2. Universiti Tun Hussein Onn Malaysia (UTHM), Faculty of Applied Science and Technology (FAST), Department of Physics and Chemistry , 84600 Panchor, Muar, Johor, Malaysia
  3. Częstochowa University of Technology, Department of Physics, Al. A. Krajowej 19, 42-200 Częstochowa, Poland
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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

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

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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Bibliography

[1] Y.-T. Yang and S. Yang. Numerical study of turbulent flow in two-dimensional channel with surface mounted obstacle. International Journal of Heat and Mass Transfer, 37(18):2985–2991, 1994. doi: 10.1016/0017-9310(94)90352-2.
[2] K. Sivakumar, T. Sampath Kumar, S. Sivasankar, V. Ranjithkumar, and A. Ponshanmugakumar. Effect of rib arrangements on the flow pattern and heat transfer in internally ribbed rectangular divergent channels. Materials Today: Proceedings, 46(9):3379–3385, 2021. doi: 10.1016/j.matpr.2020.11.548.
[3] T.M. Liou, S.W. Chang, and S.P. Chan. Effect of rib orientation on thermal and fluid-flow features in a two-pass parallelogram channel with abrupt entrance. International Journal of Heat and Mass Transfer, 116:152–165, 2018. doi: 10.1016/j.ijheatmasstransfer.2017.08.094.
[4] W. Yang, S. Xue, Y. He, and W. Li. Experimental study on the heat transfer characteristics of high blockage ribs channel. Experimental Thermal and Fluid Science, 83:248–259, 2017. doi: 10.1016/j.expthermflusci.2017.01.016.
[5] F.B. Teixeira, M.V. Altnetter, G. Lorenzini, B.D. do A. Rodriguez, L.A.O. Rocha, L.A. Isoldi, and E.D. dos Santos. Geometrical evaluation of a channel with alternated mounted blocks under mixed convection laminar flows using constructal design. Journal of Engineering Thermophysics, 29(1): 92–113, 2020. doi: 10.1134/S1810232820010087.
[6] A. Korichi and L. Oufer. Numerical heat transfer in a rectangular channel with mounted obstacles on upper and lower walls. International Journal of Thermal Sciences, 44(7):644–655, 2005. doi: 10.1016/j.ijthermalsci.2004.12.003.
[7] L.C. Demartini, H.A. Vielmo, and S.V. Möller. Numeric and experimental analysis of the turbulent flow through a channel with baffle plates. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 26(2):153–159, 2004. doi: 0.1590/S1678-58782004000200006.
[8] Y.T. Yang and C.Z. Hwang. Calculation of turbulent flow and heat transfer in a porous-baffled channel. International Journal of Heat and Mass Transfer, 46(5):771–780, 2003. doi: 0.1016/S0017-9310(02)00360-5.
[9] G. Wang, T. Chen, M. Tian, and G. Ding. Fluid and heat transfer characteristics of microchannel heat sink with truncated rib on sidewall. International Journal of Heat and Mass Transfer, 148:119142, 2020. doi: 10.1016/j.ijheatmasstransfer.2019.119142.
[10] S. Mahjoob and S. Kashkuli. Thermal transport analysis of injected flow through combined rib and metal foam in converging channels with application in electronics hotspot removal. International Journal of Heat and Mass Transfer, 177:121223, 2021. doi: 10.1016/j.ijheatmasstransfer.2021.121223.
[11] L. Chai, G.D. Xia, and H.S. Wang. Numerical study of laminar flow and heat transfer in microchannel heat sink with offset ribs on sidewalls. Applied Thermal Engineering, 92:32–41, 2016. doi: 10.1016/j.applthermaleng.2015.09.071.
[12] Y. Yin, R. Guo, C. Zhu, T. Fu, and Y. Ma. Enhancement of gas-liquid mass transfer in microchannels by rectangular baffles. Separation and Purification Technology, 236:116306, 2020. doi: 10.1016/j.seppur.2019.116306.
[13] A. Behnampour O.A. Akbari, M.R. Safaei, M. Ghavami, A. Marzban, G.A.S. Shabani, M. Zarringhalam, and R. Mashayekhi. Analysis of heat transfer and nanofluid fluid flow in microchannels with trapezoidal, rectangular and triangular shaped ribs. Physica E: Low-Dimensional Systems and Nanostructures, 91:15–31, 2017. doi: 10.1016/j.physe.2017.04.006.
[14] M.R. Gholami, O.A. Akbari, A. Marzban, D. Toghraie, G.A.S. Shabani, and M. Zarringhalam. The effect of rib shape on the behavior of laminar flow of {oil/MWCNT} nanofluid in a rectangular microchannel. Journal of Thermal Analysis and Calorimetry, 134(3):1611–1628, 2018. doi: 10.1007/s10973-017-6902-3.
[15] O.A. Akbari, D. Toghraie, A. Karimipour, M.R. Safaei, M. Goodarzi, H. Alipour, and M. Dahari. Investigation of rib’s height effect on heat transfer and flow parameters of laminar water-{Al2O3} nanofluid in a rib-microchannel. Applied Mathematics and Computation, 290:135–153, 2016. doi: 10.1016/j.amc.2016.05.053.
[16] B. Mondal, S. Pati, and P.K. Patowari. Analysis of mixing performances in microchannel with obstacles of different aspect ratios. Journal of Process Mechanical Engineering, 233(5):1045–1051, 2019. doi: 10.1177/0954408919826748.
[17] L. Chai, G.D. Xia, and H.S. Wang. Parametric study on thermal and hydraulic characteristics of laminar flow in microchannel heat sink with fan-shaped ribs on sidewalls -- Part 2: Pressure drop. International Journal of Heat and Mass Transfer, 97:1081–1090, 2016. doi: 10.1016/j.ijheatmasstransfer.2016.02.076.
[18] P. Pontes, I. Gonçalves, M. Andredaki, A. Georgoulas, A.L.N. Moreira, and A.S. Moita. Fluid flow and heat transfer in microchannel devices for cooling applications: Experimental and numerical approaches. Applied Thermal Engineering, 218:119358, 2023. doi: 10.1016/j.applthermaleng.2022.119358.
[19] B.K. Srihari, A. Kapoor, S. Krishnan, and S. Balasubramanian. Computational fluid dynamics studies on the flow of fluids through microchannel with intentional obstacles. AIP Conference Proceedings, 2516(1):170003. doi: 10.1063/5.0108550.
[20] T. Grzebyk and A. Górecka-Drzazga. Vacuum microdevices. Bulletin of the Polish Academy of Sciences: Technical Sciences, 60(1):19–23, 2012. doi: 10.2478/v10175-012-0004-y.
[21] M. Kmiotek and A. Kucaba-Piętal. Influence of slim obstacle geometry on the flow and heat transfer in microchannels. Bulletin of the Polish Academy of Sciences: Technical Sciences, 66(2):111–118, 2018. doi: 10.24425/119064.
[22] S. Baheri Islami, B. Dastvareh, and R. Gharraei. An investigation on the hydrodynamic and heat transfer of nanofluid flow, with non-Newtonian base fluid, in micromixers. International Journal of Heat and Mass Transfer, 78:917–929, 2014. doi: 10.1016/j.ijheatmasstransfer.2014.07.022.
[23] S. Baheri Islami, B. Dastvareh, and R. Gharraei. Numerical study of hydrodynamic and heat transfer of nanofluid flow in microchannels containing micromixer. International Communications in Heat and Mass Transfer, 43:146–154, 2013. doi: 10.1016/j.icheatmasstransfer.2013.01.002.
[24] C.K. Chung, C.Y. Wu, and T.R. Shih. Effect of baffle height and reynolds number on fluid mixing, Microsystem Technologies, 14(9-11):1317–1323, 2008, doi: 10.1007/s00542-007-0511-1.
[25] I. Adina R&D, Theory and Modling Guide, Vollume III: ADINA CFD&FSI, Report ARD. 2019.
[26] P.J. Roache. Verification and Validation in Computational Science and Engineering. Hermosa Publishers, 1998.
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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

Myocardial extracellular volume (ECV) expansion is associated with myocardial abnormalities such as interstitial fibrosis, inflammation or amyloid deposition. Our aim was to search for correlates of ECV fraction (ECVF) derived from routine cardiac computed tomography (CT) of real-world patients. We retrospectively calculated ECVF from archived chest CT scans performed in 103 patients (51 women and 52 men; mean age: 66 ± 13 years) during a diagnostic work-up based on clinical indications. From recorded echocardiographic images, we calculated indices of left ventricular (LV) structure and function, including systolic (S’) and diastolic (E’ and A’) mitral annular velocities. There were no significant relations between ECVF and clinical or echocardiographic parameters. LV function was comparable according to median ECVF (24.7%) (S’: 10.4 ± 4.1 vs. 9.5 ± 8.0 cm/s; E’: 9.2 ± 3.4 vs. 9.4 ± 3.1 cm/s; E’/A’ ratio: 1.0 ± 0.6 vs. 1.2 ± 0.9; E/E’ ratio: 9.0 ± 4.8 vs. 9.4 ± 5.8 for ECVF above and below the median, respectively). S’ and E’ were positively correlated in 52 subjects with an over-median ECVF (r = 0.46, p = 0.001), in contrast to their 51 counterparts with a below-median ECVF (r = 0.15, p = 0.3). In conclusion, ECV expansion might be associated with a marked interdependence of S’ and E’, corresponding to systolic and early diastolic LV performance, respectively. As E’ is a rough surrogate index of LV active relaxation, these findings could reflect a contribution of LV fibrosis to early LV diastolic dysfunction, known to coincide with discrete LV long-axis systolic dysfun
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Authors and Affiliations

Jakub Nowak
1
Maksym Sikora
1
Michał Drabik
1
Maria Kurek
1
Ewa Wieczorek-Surdacka
2
Bernadeta Chyrchel
3 4
Tadeusz Popiela
4

  1. Students’ Scientific Group at the Second Department of Cardiology, Institute of Cardiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
  2. Center for Innovative Medical Education, Jagiellonian University Medical College, Kraków, Poland
  3. Second Department of Cardiology, Institute of Cardiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
  4. Department of Radiology, Jagiellonian University Medical College, Kraków, Pola
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Abstract

Intraorbital foreign bodies still remain an unsolved and serious diagnostic problem. Due to the complicated anatomical orbital structure, both the diagnosis and treatment of these injuries are considered to be one of the most challenging. We present a case of a metallic foreign body (a bullet) imbeded in the orbit of a 10-year-old boy. Only after performing computed tomography imaging using the metal artifacts reduction algorithm it was possible to properly localize the foreign body. The issue of intraorbital foreign bodies is interdisciplinary and requires the co-operation between many specialists, including ophthalmologists, otorhinolaryngologists and radiologists.
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Authors and Affiliations

Mateusz Dworak
1
Kamila Stolcman-Mrugała
1
Zuzanna Gałuszka
1
Karolina Pasierb
1
Robert Chrzan
2
Jacek Składzień
1

  1. Chair and Department of Otolaryngology, Jagiellonian University Medical College, Kraków, Poland
  2. Chair of Radiology, Jagiellonian University Medical College, Kraków, Poland
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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

Swarm intelligence algorithms are widely recognized for their efficiency in solving complex optimization problems. However, their scalability poses challenges, particularly with large problem instances. This study investigates the time performance of swarm intelligence algorithms by leveraging parallel computing on both central processing units (CPUs) and graphics processing units (GPUs). The focus is on optimizing algorithms designed for range search in Euclidean space to enhance GPU execution. Additionally, the study explores swarm-inspired solutions specifically tailored for GPU implementations, emphasising improving efficiency in video rendering and computer simulations. The findings highlight the potential of GPU-accelerated swarm intelligence solutions to address scalability challenges in large-scale optimization, offering promising advancements in the field.
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Authors and Affiliations

Łukasz Michalski
1
Andrzej Sołtysik
1
Marek Woda
1

  1. Department of Computer Engineering, Wroclaw University of Technology, Poland

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

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

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