BazTech - Yadda

1

On the path partition of graphs

Kouider Mekkia, Zamime Mohamed

Opuscula Mathematica

|

2023

|

Vol. 43, no. 6

829--839

EN

Let G be a graph of order n. The maximum and minimum degree of G are denoted by Δ and δ, respectively. The path partition number μ(G) of a graph G is the minimum number of paths needed to partition the vertices of G. Magnant, Wang and Yuan conjectured that [formula]. In this work, we give a positive answer to this conjecture, for Δ ≥ 2δ.

2

Minimization of empty truck runs. Formulation of problem

Ambroziak Tomasz, Pawłowski Daniel

Research in Logistics & Production

|

2019

|

Vol. 9, No. 2

77--87

EN

The article formulates the issue of minimizing empty runs. Then, the interpretation of the issue of empty runs on numerical examples is presented. The formulation of the issue of minimizing empty runs requires the formulation of two optimization problems. The first one concerns distribution of commodities with minimal cost. The optimization problem formulated in this way is a well-known transport problem with the objective function being the costs of transport. The second one concerns commodity transport with distance minimization. After solving these two issues, the circulation problem of transport means is solved. Thanks to which we obtain the minimum number of empty runs expressed in distance units.

3

A note on the density of the strong product of graphs

Pikies T.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

|

2018

|

T. 23

97--103

EN

This paper presents some lower and upper bounds on the density of a graph in its strong powers. They were created using the basic graph parameters and using basic properties of the strong product. The created bounds were sufficient to make a general conclusion about how the density in the strong powers of a graph behaves. On the basis of these considerations a simple conclusion follows on the merit of graph algorithms sensitive to the number of edges for applications to this type of graphs.

PL

Praca zawiera pewne dolne oraz górne ograniczenia dla gęstości silnych potęg grafu. Zostały one wyznaczone przy pomocy podstawowych parametrów grafu oraz podstawowych własności silnego produktu. Wyznaczone ograniczenia są wystarczające do wysnucia prostych wniosków odnośnie zachowanie gęstości w silnych potęgach grafu. Wnioski te świadczą o zasadności stosowania algorytmów wrażliwych na ilość krawędzi przy badaniu silnych potęg grafów.

4

Analiza możliwości poprawy własności transmisyjnych sieci dzięki zastosowaniu sterowania jej zasobami

Drzycimski Z., Bujnowski D.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

|

2018

|

nr 8-9

760--763, CD

PL

Niniejszy artykuł dotyczy możliwości poprawy własności transmisyjnych sieci telekomunikacyjnych opisanych grafami nieregularnymi, dzięki wykorzystaniu wyznaczonych współczynników nierównomierności do sterowania posiadanymi zasobami sieciowymi.

EN

These article concerns the possibility of improving the transmission properties of telecommunications networks described by irregular networks graphs, by use of designated unequal coefficients to control the network resources.

5

Connected domination polynomial of graphs

Mojdeh D. A., Emadi A. S.

Fasciculi Mathematici

|

2018

|

Nr 60

103--121

EN

Let G be a simple graph of order n. The connected domination polynomial of G is the polynomial Dc (G, x) = Σ |V(G)| i=γc(G) dc (G, i)xi, where dc (G, i) is the number of connected dominating sets of G of size i and γc (G) is the connected domination number of G. In this paper we study Dc (G, x) of any graph. We classify many families of graphs by studying their connected domination polynomial.

6

Properties of an α-clique approach to obtaining the hub and spoke structure in optimization of transportation systems

Mazbic-Kulma B., Owsinski J. W., Barski A., Sęp K., Stańczak J.

Control and Cybernetics

|

2018

|

Vol. 47, no. 2

173--189

EN

The paper is devoted to the analysis of a graph transformation, pertinent for the transport and logistic systems and their planning and management. Namely, we consider, for a given graph, representing some existing transport or logistic system, its transformation to a (non-equivalent) so-called ”hub-and-spoke” structure, known from both literature and practice of transportation and logistics. This structure is supposed to bring beneﬁts in terms of functioning and economic performance of the respective systems. The transformation into the ”hub-and-spoke” is not only non-equivalent (regarding the original graph of the system), but is also, in general, non unique. The structure sought is composed of two kinds of elements - nodes of the graph (stations, airports, havens, etc.), namely: the subgraph of hubs, which, in principle, ought to constitute a complete sub-graph (a clique), and the ”spokes”, i.e. the subsets of nodes, each of which is connected in the ultimate structure only with one of the hubs. The paper proposes a relaxation of the hub-and-spoke structure by allowing the hub subgraph not to be complete, but at least connected, with a deﬁnite ”degree of completeness” (alpha), from where the name of ”alpha-clique”. It is shown how such structures can be obtained and what are the resulting beneﬁts for various assumptions, regarding such structures. The beneﬁts are measured here with travel times. The desired structures are sought with an evolutionary algorithm. It is shown on an academic example how the results vary and how the conclusions, relevant for practical purposes, can be drawn from such analyses, done with the methods here presented.

7

Review of The Data Modeling Standards and Data Model Transformation Techniques

Jaskierny Leszek

Applied Computer Science

|

2018

|

Vol. 14, no 4

93--108

EN

Manual data transformations that result in high error rates are a big problem in complex integration and data warehouse projects, resulting in poor quality of data and delays in deployment to production. Automation of data trans-formations can be easily verified by humans; the ability to learn from past decisions allows the creation of metadata that can be leveraged in future mappings. Significant improvement of the quality of data transformations can be achieved, when at least one of the models used in transformation is already analyzed and understood. Over recent decades, particular industries have defined data models that are widely adopted in commercial and open source solutions. Those models (often industry standards, accepted by ISO or other organizations) can be leveraged to increase reuse in integration projects resulting in a) lower project costs and b) faster delivery to production. The goal of this article is to provide a comprehensive review of the practical applications of standardization of data formats. Using use cases from the Financial Services Industry as examples, the author tries to identify the motivations and common elements of particular data formats, and how they can be leveraged in order to automate process of data transformations between the models.

8

Projektowanie zdecentralizowanych struktur komputerowych systemów sterowania ruchem kolejowym

Wontorski P., Kochan A.

Zeszyty Naukowo-Techniczne Stowarzyszenia Inżynierów i Techników Komunikacji w Krakowie. Seria: Materiały Konferencyjne

|

2017

|

Nr 2(113)

173--185

PL

W artykule przedstawiono koncepcję projektowania zdecentralizowanych struktur komputerowych systemów sterowania ruchem kolejowym (srk). W formułowaniu założeń posłużono się praktycznymi aspektami projektowania i instalacji urządzeń srk. Zaproponowano podejście oparte na agregacji urządzeń wewnętrznych srk do autonomicznych zespołów urządzeń wewnętrznych, jako szczególnego typu punktów rozdzielczych (węzłowych) struktury urządzeń i połączeń. Jest to podejście alternatywne do tradycyjnego, opartego na modelu z pełną centralizacją. Strukturę urządzeń i połączeń scharakteryzowano poprzez wybrane właściwości (liczba i rozmieszczenie węzłów, stopień centralizacji, topologia sieci), a następnie zdefiniowano za pomocą grafu, gdzie wierzchołki stanowią punkty rozdzielcze a krawędzie – połączenia. W rozważaniach wskazano trzy główne kierunki suboptymalizacji modelu: kosztowy, niezawodnościowy i dotyczący dostępności systemu.

EN

The article presents the concept of designing decentralized computer structures of railway traffic control systems (rtc). While formulation of the assumptions, the practical aspects of the design and installation of srk devices have been used. The approach was based on the aggregation of internal devices rtc to autonomous units of internal devices as a special type of distribution points (nodes) of devices and connections. This is an alternative approach to traditional, model-based, full centralization. The structure of devices and connections was characterized by selected properties (number and distribution of nodes, degree of centralization, network topology), and then defined by graph, where vertices are the distribution points and the edges - connections. Three main directions of sub-optimization of the model have been pointed out: cost, reliability and availability of the system.

9

Pattern-based Rewriting through Abstraction

Bottoni P., Guerra E., de Lara J.

Fundamenta Informaticae

|

2016

|

Vol. 144, nr 2

109--160

EN

Model-based development relies on models in different phases for different purposes, with modelling patterns being used to document and gather knowledge about good practices in specific domains, to analyse the quality of existing designs, and to guide the construction and refactoring of models. Providing a formal basis for the use of patterns would also support their integration with existing approaches to model transformation. To this end, we turn to the commonly used, in this context, machinery of graph transformations and provide an algebraic-categorical formalization of modelling patterns, which can express variability and required/forbidden application contexts. This allows the definition of transformation rules having patterns in left and right-hand sides, which can be used to express refactorings towards patterns, change the use of one pattern by a different one, or switch between pattern variants. A key element in our proposal is the use of operations to abstract models into patterns, so that they can be manipulated by pattern rules, thus leading to a rewriting mechanism for classes of graphs described by patterns and not just individual graphs. The proposal is illustrated with examples in object-oriented software design patterns and enterprise architecture patterns, but can be applied to any other domain where patterns are used for modelling.

10

Opracowanie wyników pomiarów według konwencji GUM oraz jej praktyczne wykorzystanie w dydaktyce

Maksyś R., Podoski T., Taszner A.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2015

|

nr 91

78--91

PL

Praca zawiera omówienie obowiązujących norm oceny niepewności pomiarowych oraz sugestie dotyczące graficznej analizy wyników pomiarowych, dających się przedstawić w postaci liniowej. Wykorzystując pomiary wykonane przez studentów, przeanalizowano korzyści z zastosowania analizy statystycznej wyników według konwencji GUM. Poniższe rozważania będą pomocne zarówno w dydaktyce, jak i w przyszłej pracy inżynierskiej absolwentów.

EN

Methods presented in this paper of data analysis are now widely used both in industry and metrology. They are designed to standardize procedures of data evaluation and description of the experimental uncertainties. In discussed issues it is recommended to use GUM’s procedure. Objective, contemporary visualization method of measurement results is the method of least- squares. This method is implemented in all the spreadsheets and is widely available. Students of technical studies are familiar, at least at a basic level with spreadsheets. These skills should be used and developed in accordance with applicable standards in the classroom not only in the physical laboratory. Wide availability of graphics programs encourages their use in the preparation of charts. Handwritten plots become anachronistic. Some mathematical formulas described in the paper can be used by students in the classroom, despite the lack of undergraduates’ advanced knowledge of mathematics.

11

Local dependency in networks

Kudělka M., Zehnalová Š., Horák Z., Krömer P., Snášel V.

International Journal of Applied Mathematics and Computer Science

|

2015

|

Vol. 25, no. 2

281--293

EN

Many real world data and processes have a network structure and can usefully be represented as graphs. Network analysis focuses on the relations among the nodes exploring the properties of each network. We introduce a method for measuring the strength of the relationship between two nodes of a network and for their ranking. This method is applicable to all kinds of networks, including directed and weighted networks. The approach extracts dependency relations among the network's nodes from the structure in local surroundings of individual nodes. For the tasks we deal with in this article, the key technical parameter is locality. Since only the surroundings of the examined nodes are used in computations, there is no need to analyze the entire network. This allows the application of our approach in the area of large-scale networks. We present several experiments using small networks as well as large-scale artificial and real world networks. The results of the experiments show high effectiveness due to the locality of our approach and also high quality node ranking comparable to PageRank.

12

Computational studies of TTR related amyloidosis: exploration of conformational space through petri net-based algorithm

Jakubowski R., Gogolińska A., Pepłowski Ł., Skrzyniarz P., Nowak W.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

|

2014

|

Vol. 18, No 3

289--300

EN

Amyloidosis, a serious and widespread disease with a genetic background , manifests itself through the formation of dangerous fibrils in various organs. Apart from th e polluted environment and an unhealthy lifestyle, genetic factors may acceler ate this process leading in some cases to lethal damages to the body. Recently, a growing interest i n amyloidogenic protein research has been observed. Transthyretin ( TTR ) is a tetrameric protein that transports thyroid hormone thyroxine and retinol binding protein in plasma and the cerebr al fluid. Sometimes TTR breaks apart and forms fibrils. Several single point mutations, having de stabilizing impact on the TTR complex, are involved in the amyloidogenic TTR cascade. Problems with the TTR tetramer stability and conformational space characteristics of the protein have not been addressed computationally before. We present selected results of our molecular dynamics ( MD , ∼ 2000ns) and steered MD simulations ( SMD ) of three variants of TTR : Wild Type ( WT ), V 30 M and L 55 P . SMD has been used to enforce the dissociation of TTR . Conformational spaces of WT TTR and its amyloidogenic variants have been investigated using a novel “ One Place One Conformation ” ( OPOC ) algorithm based on a graph technique called Petri net ( PN ) formalism. While the PN approach alone does not permit a direct identification of protein regions wi th reduced stability, it gives quite a useful tool for an effective compari son of complex protein energy landscapes explored during classical and/or SMD steered molecular dynamics simulations.

13

Graph based discrete optimization in structural dynamics

Blachowski B., Gutkowski W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2014

|

Vol. 62, nr 1

91--102

EN

In this study, a relatively simple method of discrete structural optimization with dynamic loads is presented. It is based on a tree graph, representing discrete values of the structural weight. In practical design, the number of such values may be very large. This is because they are equal to the combination numbers, arising from numbers of structural members and prefabricated elements. The starting point of the method is the weight obtained from continuous optimization, which is assumed to be the lower bound of all possible discrete weights. Applying the graph, it is possible to find a set of weights close to the continuous solution. The smallest of these values, fulfilling constraints, is assumed to be the discrete minimum weight solution. Constraints can be imposed on stresses, displacements and accelerations. The short outline of the method is presented in Sec. 2. The idea of discrete structural optimization by means of graphs. The knowledge needed to apply the method is limited to the FEM and graph representation. The paper is illustrated with two examples. The first one deals with a transmission tower subjected to stochastic wind loading. The second one with a composite floor subjected to deterministic dynamic forces, coming from the synchronized crowd activities, like dance or aerobic.

14

Referential graphs

Ledziński D., Marciniak B., Śrutek M.

Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy

|

2013

|

z. 17

37--73

EN

The authors of this paper have defined the notion of referential graphs which allow to model data and telecommunication networks in order to optimize them. Parameters of this type of graphs can be compared with parameters of modified chordal rings three and four degree. A description of the program developed for graphs of this type and its effects have been presented.

PL

W artykule zdefiniowano pojęcie Grafu Referencyjnego, za pomocą którego można modelować sieci teleinformatyczne w celu ich optymalizacji. Zdefiniowano parametry takiego typu grafów, które zostały porównane z parametrami modyfikowanych pierścieni cięciwowych trzeciego i czwartego stopnia. Do modelowania poszczególnych przypadków opracowano program symulacyjny. Zaprezentowano opis tego programu oraz wyniki otrzymane przy wyszukiwaniu grafów referencyjnych dla szerokiego spektrum danych wejściowych.

15

Analiza wpływu poziomu mocy sygnałów radiowych na skuteczność akwizycji danych w sieciach wykorzystujących technologię WSN

Zabłudowski Ł., Dubalski B., Drzycimski Z.

Rynek Energii

|

2013

|

Nr 1

62--68

PL

Celem niniejszego artykułu jest przedstawienie wyników analizy wpływu zmiany poziomu emisji sygnału radiowego w sensorowych sieciach bezprzewodowych (WSN) na sprawność tych sieci, a ściśle mówiąc na prawdopodobieństwo skutecznej transmisji informacji pomiędzy węzłami nadawczymi i odbiorczymi przy zastosowaniu protokołu „Hot-Potato”.

EN

The purpose of this paper is to present the results of the analysis of the impact of changes in the radio emission in sensor wireless networks (WSN) on the performance of these networks, and strictly speaking, the probability of successful transmission of information between transmitting and receiving nodes using the "Hot Potato" protocol.

16

Automation of roof area calculation process

Bera A.

Management and Production Engineering Review

|

2013

|

Vol. 4, No. 3

4--9

EN

The paper presents approach that allows to automate roof area calculation process as well as other accompanying actions. These actions include: figure recognition, calculation of necessary dimensions, recognition of connections between roof surfaces, visualization of the roof in three-dimensional space and calculation of the roof area based on processed data. The aim of proposed approach is to automate as much actions as it is possible to reduce calculation errors and moreover increase the efficiency of whole process. Presented idea has been implemented and then tested for accuracy of calculations and capabilities. Performed tests showed that presented method is flexible and gives relatively small error during roof area calculation.

17

Power level impact of radio signals on the effectiveness of transmission protocol with the usage of the "Hot-Potato" protocol in WSN networks

Zabłudowski Ł., Drzycimski Z., Kiedrowski P.

Elektronika : konstrukcje, technologie, zastosowania

|

2013

|

Vol. 54, nr 8

99-106

PL

Praca ta przedstawia rezultaty analizy zmian w emisji sygnałów radiowych w sieciach WSN na ich sprawność. Odnosi się to do określenia prawdopodobieństwa wykonania poprawnej transmisji pomiędzy węzłami nadawczymi i odbiorczymi z wykorzystaniem protokołu „Hot-Potato".

EN

This paper presents the results of the analysis of changes in the radio emission in wireless sensor networks (WSN) on the performance of these networks. This regards to the probability of successful transmission of information between transmitting and receiving nodes using the "Hot Potato" protocol.

18

Modelling and Simulation of Utility Service Provision for Sustainable Communities

Strzelecka A., Skworcow P.

International Journal of Electronics and Telecommunications

|

2012

|

Vol. 58, No. 4

389-396

EN

Utility service provision is designed to satisfy basic human needs. The main objective of the research is to investigate mathematical methods for evaluating the feasibility of using a more efficient approach for utility services provision, compared to the current diversity of utility products delivered to households. Possibilities for alternative utility service provision that lead to more sustainable solutions include reducing the number of delivered utility products, on-site recycling and use of locally available natural resources. The core of the proposed approach is the simulation system that enables carrying out feasibility study of so-called transformation graph, which describes direct transformations and indirect transformations of the utility products into defined services. The simulation system was implemented in C# and .NET 3.5, while the XML database was implemented using eXist-db. The XML database stores information about all devices, utility products, services and technologies that can be used to define and solve services-provision problems. An example of such problem and its solution is presented in this paper. This research is a part of the All-in-One Project.

19

Wykrywanie modyfikacji kształtu brył z wykorzystaniem algorytmów grafowych

Mikoda J.

Metody Informatyki Stosowanej

|

2011

|

nr 2

89-95

EN

This article presents new method for improving efficiency of applications used for fulfilling given shape with tetrahedral elements. The new approach involves searching for areas in which the shape has changed, and regeneration of mesh elements only in those areas. This operation requires using of fast algorithm for comparision of two independent areas. As a result of comparison a set of areas that should be modified is obtained. Description based on graph was used to describe areas shape while searching for modified areas. Using graphs built on the basis of original and modified shape description allows for using graph algorithms. Using algorithms designed for graph searching and dividing subgraphs made it possible to make faster and simplify process of searching for modified areas.

20

The supply of formal notions to synthesis of the vibrating discrete-continuous mechatronic systems

Buchacz A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2011

|

Vol. 44, nr 2

168--178

EN

Purpose of this paper is modeling by different category graphs and analysis of vibrating clamped - free mechatronic system by the approximate method called Galerkin’s method. Such approach considers the frequency - modal analysis and assignment of amplitude - frequence charcteristics of the mechatronic system. Design/methodology/approach: was to nominate the relevance or irrelevance between the characteristics obtained by exact - only for shaft - and considered method. Such formulation especially concerns the relevance the relevance of the natural frequencies-poles of characteristics both of mechanical subsystem and the discrete - continuous clamped - free vibrating mechatronic system. Finding this approach is a fact, that approximate solutions fulfill all conditions for vibrating mechanical and/ or mechatronic systems and can be an introduction to synthesis of these systems modeled by different category graphs. Research limitations/implications: Research limitation is that both torsional vibrating continuous mechanical subsystem and mechatronic discrete - continuous subsystems are linear discrete - continuous are linear systems. Practical implications: of this study is that the main point can be the introduction to synthesis of considered class mechatronic bar-systems with constant changeable cross-section. Originality/valut Originality of such formulation rely on the use of the hypergraph methods of modelling and synthesis of torsionally vibrating bars to the synthesis of discrete-continuous mechatronic systems.