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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Stať ve sborníku
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.

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.

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.
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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.
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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.
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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.

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.
Typ
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.

Expanding Normalized Systems from textual domain descriptions using TEMOS

Autoři
Šenkýř, D.; Suchánek, M.; Kroha, P.; Mannaert, H.; Pergl, R.
Rok
2022
Publikováno
Journal of Intelligent Information Systems. 2022, ISSN 1573-7675.
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Článek
Anotace
Functional requirements on a software system are traditionally captured as text that describes the expected functionality in the domain of a real-world system. Natural language processing methods allow us to extract the knowledge from such requirements and transform it, e.g., into a model. Moreover, these methods can improve the quality of the requirements, which usually suffer from ambiguity, incompleteness, and inconsistency. This paper presents a novel approach to using natural language processing. We use the method of grammatical inspection to find specific patterns in the description of functional requirement specifications (written in English). Then, we transform the requirements into a model of Normalized Systems elements. This may realize a possible component of the eagerly awaited text-to-software pipeline. The input of this method is represented by textual requirements. Its output is a running prototype of an information system created using Normalized Systems (NS) techniques. Therefore, the system is ready to accept further enhancements, e.g., custom code fragments, in an evolvable manner ensured by compliance with the NS principles. A demonstration of pipeline implementation is also included in this paper. The text processing part of our pipeline extends the existing pipeline implemented in our system TEMOS, where we propose and implement methods of checking the quality of textual requirements concerning ambiguity, incompleteness, and inconsistency.

Flexible Placements of Graphs with Rotational Symmetry

Autoři
Dewar, S.; Grasegger, G.; Legerský, J.
Rok
2022
Publikováno
2nd IMA Conference on Mathematics of Robotics. Cham: Springer, 2022. p. 89-97. Springer Proceedings in Advanced Robotics. vol. 21. ISSN 2511-1256. ISBN 978-3-030-91351-9.
Typ
Stať ve sborníku
Anotace
We study the existence of an n-fold rotationally symmetric placement of a symmetric graph in the plane allowing a continuous deformation that preserves the symmetry and the distances between adjacent vertices. We show that such a flexible placement exists if and only if the graph has a NAC-colouring satisfying an additional property on the symmetry; a NAC-colouring is a surjective edge colouring by two colours such that every cycle is either monochromatic, or there are at least two edges of each colour.

Highways in Warehouse Multi-Agent Path Finding: A Case Study.

Rok
2022
Publikováno
Proceedings of the 14th International Conference on Agents and Artificial Intelligence. Madeira: SciTePress, 2022. p. 274-281. ISBN 978-989-758-547-0.
Typ
Stať ve sborníku
Anotace
Orchestrating warehouse sorting robots each transporting a single package from the conveyor belt to its destination is a NP-hard problem, often modeled Multi-agent path-finding (MAPF) where the environment is represented as a graph and robots as agents in vertices of the graph. However, in order to maintain the speed of operations in such a setup, sorting robots must be given a route to follow almost at the moment they obtain the package, so there is no time to perform difficult offline planning. Hence in this work, we are inspired by the approach of enriching conflict-based search (CBS) optimal MAPF algorithm by so-called highways that increase the speed of planning towards on-line operations. We investigate whether adding highways to the underlying graph will be enough to enforce global behaviour of a large number of robots that are controlled locally. If we succeed, the slow global planning step could be omitted without significant loss of performance.

Length-bounded cuts: Proper interval graphs and structural parameters

Autoři
Bentert, M.; Heeger, K.; Knop, D.
Rok
2022
Publikováno
Journal of Computer and System Sciences. 2022, 126 21-43. ISSN 0022-0000.
Typ
Článek
Anotace
We study the LENGTH-BOUNDED CUT problem for special graph classes and from a parameterized complexity viewpoint. Here, we are given a graph G, two vertices s and t, and positive integers β and λ. The task is to find a set F of at most β edges such that each s-t-path of length at most λ in G contains some edge in F. Bazgan et al. [20] conjectured that LENGTH-BOUNDED CUT admits a polynomial-time algorithm if the input graph is a proper interval graph. We confirm this conjecture by providing a dynamic-programming-based polynomial-time algorithm. Moreover, we strengthen the W[1]-hardness result of Dvořák and Knop for LENGTH-BOUNDED CUT parameterized by pathwidth by showing W[1]-hardness for the combined parameter pathwidth and maximum degree of the input graph. Finally, we prove that LENGTH-BOUNDED CUT is W[1]-hard for the feedback vertex number. Both our hardness results complement known XP algorithms.

Migrating Techniques from Search-based Multi-Agent Path Finding Solvers to SAT-based Approach

Autoři
Surynek, P.; Stern, R.; Boyarski, E.; Felner, A.
Rok
2022
Publikováno
Journal of Artificial Intelligence Research. 2022, 2022(73), 553-618. ISSN 1076-9757.
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Článek
Anotace
In the multi-agent path finding problem (MAPF) we are given a set of agents each with re- spective start and goal positions. The task is to find paths for all agents while avoiding collisions, aiming to minimize a given objective function. Many MAPF solvers were introduced in the past decade for optimizing two specific objective functions: sum-of-costs and makespan. Two prominent categories of solvers can be distinguished: search-based solvers and compilation-based solvers. Search-based solvers were developed and tested for the sum-of-costs objective, while the most prominent compilation-based solvers that are built around Boolean satisfiability (SAT) were designed for the makespan objective. Very little is known on the performance and relevance of solvers from the compilation-based approach on the sum-of-costs objective. In this paper, we start to close the gap between these cost functions in the compilation-based approach.

Multi-agent pathfinding with continuous time

Autoři
Andreychuk, A.; Yakovlev, K.; Surynek, P.; Stern, R.; Atzmon, D.
Rok
2022
Publikováno
Artificial Intelligence. 2022, 2022(305), ISSN 0004-3702.
Typ
Článek
Anotace
Multi-Agent Pathfinding (MAPF) is the problem of finding paths for multiple agents such that each agent reaches its goal and the agents do not collide. In recent years, variants of MAPF have risen in a wide range of real-world applications such as warehouse management and autonomous vehicles. Optimizing common MAPF objectives, such as minimizing sum-of-costs or makespan, is computationally intractable, but state-of-the-art algorithms are able to solve optimally problems with dozens of agents. However, most MAPF algorithms assume that (1) time is discretized into time steps and (2) the duration of every action is one time step. These simplifying assumptions limit the applicability of MAPF algorithms in real-world applications and raise non-trivial questions such as how to discretize time in an effective manner. We propose two novel MAPF algorithms for finding optimal solutions that do not rely on any time discretization.

Overview of Controllers of User Interface for Virtual Reality

Autoři
Nováček, T.; Jiřina, M.
Rok
2022
Publikováno
PRESENCE: Teleoperators and Virtual Environments. 2022, 1-100. ISSN 1054-7460.
Typ
Článek
Anotace
Virtual reality has been with us for several decades already, but we are still trying to find the right ways to control it. There are a lot of controllers with various purposes and means of input, each with its advantages and disadvantages, but also with specific ways to be handled. Our hands were the primary means of input for human-computer interaction for a long time. However, now we can use movements of our eyes, our feet or even our whole body to control the virtual environment, interact with it, or move from one place to another. We can achieve this with various controllers and wearable interfaces, like eye tracking, haptic suits or treadmills. There are numerous devices that we can choose from for every category, but sometimes it can be hard to pick the one that suits our intentions best. This article summarises all types of user interface controllers for virtual reality, with their main pros and cons and their comparison.

Pairs of commuting quadratic elements in the universal enveloping algebra of Euclidean algebra and integrals of motion

Autoři
Marchesiello, A.; Šnobl, L.
Rok
2022
Publikováno
Journal of Physics A: Mathematical and Theoretical. 2022, 55(14), ISSN 1751-8113.
Typ
Článek
Anotace
Motivated by the consideration of integrable systems in three spatial dimensions in Euclidean space with integrals quadratic in the momenta we classify three-dimensional Abelian subalgebras of quadratic elements in the universal enveloping algebra of the Euclidean algebra under the assumption that the Casimir invariant (p) over right arrow . (l) over right arrow vanishes in the relevant representation. We show by means of an explicit example that in the presence of magnetic field, i.e. terms linear in the momenta in the Hamiltonian, this classification allows for pairs of commuting integrals whose leading order terms cannot be written in the famous classical form of Makarov et al [17]. We consider limits simplifying the structure of the magnetic field in this example and corresponding reductions of integrals, demonstrating that singularities in the integrals may arise, forcing structural changes of the leading order terms.

Parameter Setting in SAT Solver Using Machine Learning Techniques

Autoři
Beskyd, F.; Surynek, P.
Rok
2022
Publikováno
Proceedings of the 14th International Conference on Agents and Artificial Intelligence. Madeira: SciTePress, 2022. p. 586-597. ISBN 978-989-758-547-0.
Typ
Stať ve sborníku
Anotace
Boolean satisfiability (SAT) solvers are essential tools for many domains in computer science and engineering. Modern complete search-based SAT solvers represent a universal problem solving tool which often provide higher efficiency than ad-hoc direct solving approaches. Over the course of at least two decades of SAT related research, many variable and value selection heuristics were devised. Heuristics can usually be tuned by single or multiple numerical parameters prior to executing the search process over the concrete SAT instance. In this paper we present a machine learning approach that predicts the parameters of heuristic from the underlying structure of the input SAT instance.

Road Quality Classification

Autoři
Lank, M.; Friedjungová, M.
Rok
2022
Publikováno
Image Analysis and Processing – ICIAP 2022. Cham: Springer International Publishing, 2022. p. 553-563. Lecture Notes in Computer Science. vol. 13232. ISSN 1611-3349. ISBN 978-3-031-06430-2.
Typ
Stať ve sborníku
Anotace
Road quality significantly influences safety and comfort while driving. Especially for most kinds of two-wheelers, road damage is a real threat, where vehicle components and enjoyment are heavily impacted by road quality. This can be avoided by planning a route considering the surface quality. We propose a new publicly available and manually annotated dataset collected from Google Street View photos. This dataset is devoted to a road quality classification task considering six levels of damage. We evaluated some preprocessing methods such as shadow removal, CLAHE, and data augmentation. We adapted several pre-trained networks to classify road quality. The best performance was reached by MobileNet using augmented dataset (75.55%).

Symmetric and Asymmetric Schemes for Lightweight Secure Communication

Rok
2022
Publikováno
Information Systems Security and Privacy. Basel: Springer Nature Switzerland AG, 2022. p. 97-114. ISSN 1865-0929. ISBN 978-3-030-94899-3.
Typ
Stať ve sborníku
Anotace
The paper deals with the topic of lightweight authentication and secure communication for constrained hardware devices such as IoT or embedded devices. In the paper, protocols based on both symmetric and asymmetric schemes are presented, utilizing a PUF/TRNG combined module, showing it is advantageous to have single module that will allow generation of both TRNG and PUF at the same time. This approach minimizes implementation requirements and operational resource consumption. Moreover, it allows the simplification of the overall key management process as the proposed protocols do not require to store secrets on the devices themselves. This paper is the extended and revised version of the paper entitled "Lightweight Authentication and Secure Communication Suitable for IoT Devices" [1] presented at the 6th International Conference on Information Systems Security and Privacy (ICISSP) 2020.

TARGET SET SELECTION IN DENSE GRAPH CLASSES

Autoři
Dvorak, P.; Knop, D.; Toufar, T.
Rok
2022
Publikováno
SIAM Journal on Discrete Mathematics. 2022, 36(1), 536-572. ISSN 0895-4801.
Typ
Článek
Anotace
In this paper, we study the TARGET SET SELECTION problem from a parameterized complexity perspective. Here for a given graph and a threshold for each vertex, the task is to find a set of vertices (called a target set) that activates the whole graph during the following iterative process. A vertex outside the active set becomes active if the number of so far activated vertices in its neighborhood is at least its threshold. We give two parameterized algorithms for a special case where each vertex has the threshold set to half of its neighbors (the so-called MAJORITY TARGET SET SELECTION problem) for parameterizations by the neighborhood diversity and the twin cover number of the input graph. We complement these results from the negative side. We give a hardness proof for the MAJORITY TARGET SET SELECTION problem when parameterized by (a restriction of) the modular-width -a natural generalization of both previous structural parameters. We also show the TARGET SET SELECTION problem parameterized by the neighborhood diversity or by the twin cover number is W[1]-hard when there is no restriction on the thresholds.

The DBpedia Technology Tutorial

Autoři
Dojčinovski, M.; Forberg, J.; Frey, J.; Hofer, M.; Streitmatter, D.; Yankov, K.
Rok
2022
Publikováno
LDK Workshops and Tutorials 2021. Aachen: CEUR Workshop Proceedings, 2022. vol. 3064. ISSN 1613-0073.
Typ
Stať ve sborníku
Anotace
DBpedia (https://www.dbpedia.org) is a crowd-sourced community effort which aims at extraction and publishing structured information from various Wikimedia projects. This structured information resembles an open knowledge graph, the DBpedia Knowledge Graph, which is publicly available for everyone on the Web. The DBpedia Knowledge Graph has been under development for many years and is being improved to this day. In this tutorial, participants gained general information on the DBpedia Knowledge Graph and the DBpedia community. The tutorial also provided information on the complete DBpedia Knowledge Graph lifecycle, i.e. from extraction and modelling to publishing and maintenance of the DBpedia KG. A particular focus was put on the DBpedia Infrastructure, i.e. the DBpedia’s Databus publishing platform and the associated DBpedia services, i.e. DBpedia Spotlight, DBpedia Lookup, the DBpedia service endpoints and DBpedia Archivo.

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