A Design Space Exploration Framework for Memristor-Based Crossbar Architecture

Autoři
Barbareschi, M.; Bosio, A.; O'Connor, I.; Fišer, P.; Traiola, M.
Rok
2022
Publikováno
Proceedings of the 2022 25th International Symposium on Design and Diagnostics of Electronic Circuits and Systems (DDECS). Piscataway: IEEE, 2022. p. 38-43. ISSN 2473-2117. ISBN 978-1-6654-9431-1.
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Anotace
In the literature, there are few studies describing how to implement Boolean logic functions as a memristor-based crossbar architecture and some solutions have been actually proposed targeting back-end synthesis. However, there is a lack of methodologies and tools for the synthesis automation. %More in detail, what is missing is a methodology able to optimize a given Boolean logic function for the memristor-based implementation. The main goal of this paper is to perform a Design Space Exploration (DSE) in order to analyze and compare the impact of the most used optimization algorithms on a memristor-based crossbar architecture. %The synthesized circuits are quantified in terms of area, energy consumption, and performance. The results carried out on 102 circuits lead us to identify the best optimization approach, in terms of area/energy/delay. The presented results can also be considered as a reference (benchmarking) for comparing future work.

A fair experimental evaluation of distance correlation side-channel distinguisher

Rok
2022
Publikováno
Proceedings of the 11th Mediterranean Conference on Embedded Computing (MECO 2022). Institute of Electrical and Electronics Engineers, Inc., 2022. p. 110-113. ISSN 2637-9511. ISBN 978-1-6654-6828-2.
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Anotace
Side-channel attacks pose a severe threat to crypto graphic implementations, allowing the attacker to recover secret information based on physical observations of the cryptographic device. Correlation Power Analysis is considered to be one of the most powerful attacks in the non-profiled scenario. In this paper, we consider the distance/Brownian correlation instead of the traditionally used Pearson coefficient. We give a fair comparison of our novel approach attacking AES on three different FPGA platforms and we discuss the distance correlation potential in the context of side-channel analysis.

A Survey of Guidelines and Best Practices for the Generation, Interlinking, Publication, and Validation of Linguistic Linked Data

Autoři
Khan, A.F.; Chiarcos, C.; Declerck, T.; Buono, M.P.; Dojčinovski, M.; Gracia, J.; Oleskeviciene, G.V.; Gifu, D.
Rok
2022
Publikováno
Proceedings of LDL 2022. Paris: ELRA, 2022. p. 1-9.
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Anotace
This article discusses a survey carried out within the NexusLinguarum COST Action which aimed to give an overview of existing guidelines (GLs) and best practices (BPs) in linguistic linked data. In particular it focused on four core tasks in the production/publication of linked data: generation, interlinking, publication, and validation. We discuss the importance of GLs and BPs for LLD before describing the survey and its results in full. Finally we offer a number of directions for future work in order to address the findings of the survey.

Ab initio View of Emergent Symplectic Symmetry and Its Crutial Role in Nuclear Dynamics

Autoři
Dytrych, T.; Launey, K.D.; Draayer, J.P.; Langr, D.
Rok
2022
Publikováno
Bulgarian Journal of Physics. 2022, 49(1), 37-46. ISSN 1310-0157.
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Článek
Anotace
Results of large-scale first principle nuclear structure studies using the symmetry-adapted no-core shell model are reported. It is shown that nuclei up through the intermediate-mass region display highly regular and ubiquitous patterns of dominant nuclear shapes that vibrate and rotate. This emergent structure is tied to an approximate symplectic Sp (3, R) symmetry, and it is shown to determine dominant features of low-lying states, even in close-to-spherical nuclear states without any recognizable rotational properties.

Approximate arithmetic for modern neural networks and FPGAs

Rok
2022
Publikováno
Proceedings of the 11th Mediterranean Conference on Embedded Computing (MECO 2022). Institute of Electrical and Electronics Engineers, Inc., 2022. p. 357-360. ISSN 2637-9511. ISBN 978-1-6654-6828-2.
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Stať ve sborníku
Anotace
Approximate arithmetic is a very important approach for implementing neural networks in embedded hardware. The requirements of real-time applications with respect to the size of deep neural networks force designers to simplify the neural processing elements. Not only the reduction of precision of model parameters to a few bits, but also the use of approximate arithmetic increases computational power and saves on-chip resources beyond exact computation. Since it was shown that linearly approximated functions are suitable for implementing neural networks in hardware, FPGAs have improved. So we decided to re-implement the processing element on a modern FPGA and to present implementation results regarding speed and resource consumption. A neural processing element based on linearly approximated functions was implemented in Vivado and tested on an xc7 FPGA. The results show that the architecture saves significant resources and a clock frequency above 100 MHz can be achieved in pipelined design.

Automatic Detection and Decryption of AES Using Dynamic Analysis

Autoři
Kokeš, J.; Matějka, J.; Lórencz, R.
Rok
2022
Publikováno
SN Computer Science. 2022, 2022 ISSN 2662-995X.
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Článek
Anotace
In this paper we propose a set of algorithms that can automatically detect the use of AES and automatically recover both the encryption key and the plaintext, assuming that we can control the code flow of the encrypting program, e.g., when an application is performing encryption without the user’s permission. The first algorithm makes use of the fact that we can monitor accesses to the AES S-Box and deduce the desired data from these accesses; the approach is suitable to software-based AES implementations, both naïve and optimized. To demonstrate the feasibility of this approach we designed a tool which implements the algorithm for Microsoft Windows running on the Intel x86 architecture. The tool has been successfully tested against a set of applications using different cryptographic libraries and common user applications. We also discuss the options of recovering the same data when hardware-assisted AES implementations on Intel-compatible architectures are used.

Balancing the Spread of Two Opinions in Sparse Social Networks (Student Abstract)

Rok
2022
Publikováno
Proceedings of the 36th AAAI Conference on Artificial Intelligence. Menlo Park: AAAI Press, 2022. p. 12987-12988. ISSN 2159-5399. ISBN 978-1-57735-876-3.
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Stať ve sborníku
Anotace
We propose a new discrete model for simultaneously spreading two opinions within a social network inspired by the famous Target Set Selection problem. We are given a social network, a seed-set of agents for each opinion, and two thresholds per agent. The first threshold represents the willingness of an agent to adopt an opinion if she has no opinion at all, while the second threshold states the readiness to acquire a second opinion. The goal is to add as few agents as possible to the initial seed-sets such that, once the process started with these seed-set stabilises, each agent has either both opinions or none. We perform an initial study of its computational complexity. It is not surprising that the problem is NP-hard even in quite restricted settings. Therefore, we investigate the complexity of the problem from the parameterized point-of-view with special focus on sparse networks, which appears often in practice. Among other things, we show that the proposed problem is in the FPT complexity class if we parameterize by the vertex cover number of the underlying graph.

BDDC for MHFEM discretization of unsteady two-phase flow in porous media

Autoři
Solovský, J.; Fučík, R.; Šístek, J.
Rok
2022
Publikováno
Computer Physics Communications. 2022, 271 ISSN 0010-4655.
Typ
Článek
Anotace
This work deals with the application of the Balancing Domain Decomposition by Constrains (BDDC) method to unsteady two-phase flow problems in porous media. We briefly describe the spatial discretization of the problem which is based on the mixed-hybrid finite element method (MHFEM) and semi-implicit time discretization. Then, we describe the BDDC method, in detail discuss the differences between the symmetric and nonsymmetric cases, and present the necessary modifications of the algorithm for the more complicated nonsymmetric case. We describe the parallel implementation of the method and highlight the critical steps of the algorithm that affect the performance and scalability. The parallel implementation is then tested on benchmark problems in 2D and 3D and its efficiency is investigated on various meshes. The numerical results indicate that the method preserves good computational efficiency for increasing number of processes and, therefore, allows solving problems on very fine meshes. In the case of unsteady problem, additional speed-up is achieved using the information from previous time steps for the solution in the current time step.

Bracing frameworks consisting of parallelograms

Autoři
Grasegger, G.; Legerský, J.
Rok
2022
Publikováno
The Art of Discrete and Applied Mathematics. 2022, 5(2), 1-21. ISSN 2590-9770.
Typ
Článek
Anotace
A rectangle in the plane can be continuously deformed preserving its edge lengths, but adding a diagonal brace prevents such a deformation. Bolker and Crapo characterized combinatorially which choices of braces make a grid of squares infinitesimally rigid using a bracing graph: a bipartite graph whose vertices are the columns and rows of the grid, and a row and column are adjacent if and only if they meet at a braced square. Duarte and Francis generalized the notion of the bracing graph to rhombic carpets, proved that the connectivity of the bracing graph implies rigidity and stated the other implication without proof. Nagy Kem gives the equivalence in the infinitesimal setting. We consider continuous deformations of braced frameworks consisting of a graph from a more general class and its placement in the plane such that every 4-cycle forms a parallelogram. We show that rigidity of such a braced framework is equivalent to the non-existence of a special edge coloring, which is in turn equivalent to the corresponding bracing graph being connected.

Classification of network traffic

Rok
2022
Publikováno
Proceedings of the 10th Prague Embedded Systems Workshop. Praha: CTU. Faculty of Information Technology, 2022. p. 52-58. ISBN 978-80-01-07015-4.
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Stať ve sborníku
Anotace
This paper describes the context of existing approaches to real-time net- work flow classification and focuses on the contributions of bachelor and master thesis of the author. The paper also proposes several research questions that are planned for the future Ph.D. study.

Controlling the Spread of Two Secrets in Diverse Social Networks (Student Abstract)

Rok
2022
Publikováno
Proceedings of the 36th AAAI Conference on Artificial Intelligence. Menlo Park: AAAI Press, 2022. p. 12919-12920. ISSN 2159-5399. ISBN 978-1-57735-876-3.
Typ
Stať ve sborníku
Anotace
nformation diffusion in social networks is a well-studied concept in social choice theory. We propose the study of the diffusion of two secrets in a heterogeneous environment from the complexity perspective, that is, there are two different networks with the same set of agents (e.g., the structure of the set of followers might be different in two distinct social networks). Formally, our model combines two group identification processes for which we do have independent desiderata---either constructive, where we would like a given group of agents to be exposed to a secret, or destructive, where a given group of agents should not be exposed to a secret. To be able to reach these targets, we can either delete an agent or introduce a previously latent agent. Our results are mostly negative---all of the problems are NP-hard. Therefore, we propose a parameterized study with respect to the natural parameters, the number of influenced agents, the size of the required/protected agent sets, and the duration of the diffusion process. Most of the studied problems remain W[1]-hard even for a combination of these parameters. We complement these results with nearly optimal XP algorithms.

Correlation Power Analysis of SipHash

Autoři
Olekšák, M.; Miškovský, V.
Rok
2022
Publikováno
Proceedings of the 2022 25th International Symposium on Design and Diagnostics of Electronic Circuits and Systems (DDECS). Piscataway: IEEE, 2022. p. 84-87. ISSN 2473-2117. ISBN 978-1-6654-9431-1.
Typ
Stať ve sborníku
Anotace
SipHash is ARX-based pseudorandom function optimized for short inputs. It was developed as a hash table lookup function, but it is also used for MAC generation. At the time of writing, there was no side-channel attack on SipHash known to us. This work is about application of CPA attack on SipHash. Attack was performed on ChipWhisperer CW308 UFO Board with STM32F0 target. Approximately 800 power traces were needed for succesful attack. Leakage information from XOR was used to attack cipher key. The main contribution of this work is power model of binary addition including carry propagation.

CPP11sort: A parallel quicksort based on C++ threading

Autoři
Langr, D.; Schovánková, K.
Rok
2022
Publikováno
Concurrency and Computation: Practice and Experience. 2022, 34(4), 1-11. ISSN 1532-0626.
Typ
Článek
Anotace
A new efficient implementation of the multi-threaded quicksort algorithm called CPP11sort is presented. This implementation is built exclusively upon the threading primitives of the C++ programming language itself. The performance of CPP11sort is evaluated and compared with its mainstream competitors provided by GNU, Intel, and Microsoft. It is shown that out of the considered implementations, CPP11sort mostly yields the shortest sorting times and is the only one that is portable to any conforming C++ implementation without a need of external libraries or non-standard compiler extensions. The experimental evaluation with various input data distributions resulted in parallel speedup between 16.1 and 44.2 on a 56-core server and between 6.8 and 14.5 on a 10-core workstation with enabled hyper-threading.

Cultural Diversity and Its Impact on Governance

Autoři
Evan, T.; Holý, V.
Rok
2022
Publikováno
International Journal of Intercultural Relations. 2022, ISSN 0147-1767.
Typ
Článek
Anotace
Hofstede’s six cultural dimensions make it possible to measure the culture of countries but are criticized for assuming the homogeneity of each country. In this paper, we propose two measures based on Hofstede’s cultural dimensions which take into account the heterogeneous structure of citizens with respect to their countries of origin. Using these improved measures, we study the influence of heterogeneous culture and cultural diversity on the quality of institutions measured by the six worldwide governance indicators. We use a linear regression model allowing for dependence in spatial and temporal dimensions as well as the high correlation between the governance indicators. Our results show that the effect of cultural diversity improves some of the governance indicators while worsening others depending on the individual Hofstede cultural dimension.

Discriminant Analysis on a Stream of Features

Rok
2022
Publikováno
Engineering Applications of Neural Networks. Springer, Cham, 2022. p. 223-234. ISSN 1865-0929. ISBN 978-3-031-08222-1.
Typ
Stať ve sborníku
Anotace
Online learning is a well-established problem in machine learning. But while online learning is commonly concerned with learning on a stream of samples, this article is concerned with learning on a stream on features. An online quadratic discriminant analysis (QDA) is proposed because it is fast, capable of modeling feature interactions, and it can still return an exact solution. When a new feature is inserted into a training set, the proposed implementation of QDA showed a 1000-fold speed up to scikit-learn QDA. Fast learning on a stream of features provides a data scientist with timely feedback about the importance of new features during the feature engineering phase. In the production phase, it reduces the cost of updating a model when a new source of potentially useful features appears.

Disturbance Rejection in A One-Half Vehicle Suspension Using A Fuzzy Controller

Autoři
Rok
2022
Publikováno
international scientific journal tran&MOTAUTO WORLD. 2022, 7(3), 98-102. ISSN 2367-8399.
Typ
Článek
Anotace
: Generally, passenger ride comfort can be interpreted as an attenuation of sprung mass acceleration or as peak minimization of sprung mass vertical displacement, while good handling can be characterized as an attenuation of unsprung mass acceleration. This effort devoted to passive suspension design is ineffective because improvements to ride comfort are achieved at the expense of handling and vice versa. Instead, the best result can be achieved by active suspension, i.e. when an additional force can act on the system and simultaneously improve both of these conflicting requirements. Another important goal of the control design is to maintain robustness of the closed loop system. In the paper, fuzzy logic is used to simulate active suspension control of a one-half-car model. Velocity and acceleration of the front and rear wheels and undercarriage velocity above the wheels are taken as input data of the fuzzy logic controller. Active forces improving vehicle driving, ride comfort, and handling properties are considered to be the controlled actuator outputs. The controller design is proposed to minimize chassis and wheels deflection when uneven road surfaces, pavement points, etc. are acting on tires of running cars. As a result, a comparison of an active suspension fuzzy control and a spring/damper passive suspension is shown using MATLAB simulations.

Disturbance Rejection in A One-Half Vehicle Suspension Using A Fuzzy Controller

Autoři
Rok
2022
Publikováno
Proceedings of the VIIIth International Scientific Congress "INNOVATIONS 2022". Sofia: Scientific-technical union of mechanical engineering, 2022. p. 28-32. vol. 1. ISSN 2603-3763.
Typ
Stať ve sborníku
Anotace
: Generally, passenger ride comfort can be interpreted as attenuation of sprung mass acceleration or as peak minimization of sprung mass vertical displacement, while good handling can be characterized as attenuation of unsprung mass acceleration. This effort devoted to passive suspension design is ineffective because improvements to ride comfort are achieved at the expense of handling and vice versa. Instead, the best result can be achieved by active suspension, i.e. when an additional force can act on the system and simultaneously improve both of these conflicting requirements. Another important goal of the control design is to maintain the robustness of the closed-loop system. In the paper, fuzzy logic is used to simulate active suspension control of a one-half-car model. Velocity and acceleration of the front and rear wheels and undercarriage velocity above the wheels are taken as input data of the fuzzy logic controller. Active forces improving vehicle driving, ride comfort, and handling properties are considered to be the controlled actuator outputs. The controller design is proposed to minimize chassis and wheel deflection when uneven road surfaces, pavement points, etc. are acting on the tires of running cars. As a result, a comparison of an active suspension fuzzy control and a spring/damper passive suspension is shown using MATLAB simulations.

Efficacy of the symmetry-adapted basis for ab initio nucleon-nucleus interactions for light- and intermediate-mass nuclei

Autoři
Mercenne, A.; Launey, K.D.; Dytrych, T.; Escher, J.E.; Quaglioni, S.; Sargsyan, G.H.; Langr, D.; Draayer, J.P.
Rok
2022
Publikováno
Computer Physics Communications. 2022, 280 1-11. ISSN 0010-4655.
Typ
Článek
Anotace
We study the efficacy of a new ab initio framework that combines the symmetry-adapted (SA) no-core shell-model approach with the resonating group method (RGM) for unified descriptions of nuclear structure and reactions. We obtain ab initio neutron-nucleus interactions for 4He, 16O, and 20Ne targets, starting with realistic nucleon-nucleon potentials. We discuss the effect of increasing model space sizes and symmetry-based selections on the SA-RGM norm and direct potential kernels, as well as on phase shifts, which are the input to calculations of cross sections. We demonstrate the efficacy of the SA basis and its scalability with particle numbers and model space dimensions, with a view toward ab initio descriptions of nucleon scattering and capture reactions up through the medium-mass region.

Enhancing Reactive Ad Hoc Routing Protocols with Trust

Rok
2022
Publikováno
Future Internet. 2022, 14(1), ISSN 1999-5903.
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Článek
Anotace
In wireless ad hoc networks, security and communication challenges are frequently addressed by deploying a trust mechanism. A number of approaches for evaluating trust of ad hoc network nodes have been proposed, including the one that uses neural networks. We proposed to use packet delivery ratios as input to the neural network. In this article, we present a new method, called TARA (Trust-Aware Reactive Ad Hoc routing), to incorporate node trusts into reactive ad hoc routing protocols. The novelty of the TARA method is that it does not require changes to the routing protocol itself. Instead, it influences the routing choice from outside by delaying the route request messages of untrusted nodes. The performance of the method was evaluated on the use case of sensor nodes sending data to a sink node. The experiments showed that the method improves the packet delivery ratio in the network by about 70%. Performance analysis of the TARA method provided recommendations for its application in a particular ad hoc network.

Evacuation trials from a double-deck electric train unit: Experimental data and sensitivity analysis

Autoři
Najmanová, H.; Kuklík, L.; Pešková, V.; Bukáček, M.; Vašata, D.; Hrabák, P.
Rok
2022
Publikováno
Safety Science. 2022, 146 ISSN 0925-7535.
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Článek
Anotace
Passenger trains represent a challenging environment in emergencies, with specific evacuation conditions resulting from the typical layout and interior design inherent to public transportation vehicles. This paper describes a dataset obtained in a full-scale controlled experiment emulating the emergency evacuation of a double-deck electric unit railcar carried out in Prague in 2018. 15 evacuation trials involving 91 participants were conducted under various evacuation scenarios considering different compositions of passenger crowd, exit widths, and exit types (egress to a high platform, to an open rail line using stairs, and a 750 mm jump without any supporting equipment). The study’s main goals were to collect experimental data on the movement conditions in the railcar and to study the impact of various boundary conditions on evacuation process and total evacuation time. Movement characteristics (exit flows, speeds) and human behaviour (pre-movement activities, exiting behaviours) were also analysed. The data obtained was used to validate and adjust a Pathfinder model to capture important aspects of evacuation from the railcar. Furthermore, a series of simulations using this model was performed to provide sensitivity analysis of the influence of crowd composition, exit width, and exit type on total evacuation time. As a key finding, we can conclude that for the case of a standard exit path (platform or stairs) the width of the main exit had the greatest impact on total evacuation time, however, crowd composition played the prevailing role in evacuation scenarios involving a jump.

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Za obsah stránky zodpovídá: doc. Ing. Štěpán Starosta, Ph.D.