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1

Delaunay surfaces expressed in terms of a Cartan moving frame

Bracken Paul

Journal of Applied Analysis

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2020

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Vol. 26, nr 1

153--160

EN

Delaunay surfaces are investigated by using a moving frame approach. These surfaces correspond to surfaces of revolution in the Euclidean three-space. A set of basic one-forms is defined. Moving frame equations can be formulated and studied. Related differential equations which depend on variables relevant to the surface are obtained. For the case of minimal and constant mean curvature surfaces, the coordinate functions can be calculated in closed form. In the case in which the mean curvature is constant, these functions can be expressed in terms of Jacobi elliptic functions.

2

Applying Machine Learning to Software Fault Prediction

Wójcicki B., Dabrowski R.

e-Informatica Software Engineering Journal

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2018

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Vol. 12, nr 1

199--216

EN

Introduction: Software engineering continuously suffers from inadequate software testing. The automated prediction of possibly faulty fragments of source code allows developers to focus development efforts on fault-prone fragments first. Fault prediction has been a topic of many studies concentrating on C/C++ and Java programs, with little focus on such programming languages as Python. Objectives: In this study the authors want to verify whether the type of approach used in former fault prediction studies can be applied to Python. More precisely, the primary objective is conducting preliminary research using simple methods that would support (or contradict) the expectation that predicting faults in Python programs is also feasible. The secondary objective is establishing grounds for more thorough future research and publications, provided promising results are obtained during the preliminary research. Methods: It has been demonstrated that using machine learning techniques, it is possible to predict faults for C/C++ and Java projects with recall 0.71 and false positive rate 0.25. A similar approach was applied in order to find out if promising results can be obtained for Python projects. The working hypothesis is that choosing Python as a programming language does not significantly alter those results. A preliminary study is conducted and a basic machine learning technique is applied to a few sample Python projects. If these efforts succeed, it will indicate that the selected approach is worth pursuing as it is possible to obtain for Python results similar to the ones obtained for C/C++ and Java. However, if these efforts fail, it will indicate that the selected approach was not appropriate for the selected group of Python projects. Results: The research demonstrates experimental evidence that fault-prediction methods similar to those developed for C/C++ and Java programs can be successfully applied to Python programs, achieving recall up to 0.64 with false positive rate 0.23 (mean recall 0.53 with false positive rate 0.24). This indicates that more thorough research in this area is worth conducting. Conclusion: Having obtained promising results using this simple approach, the authors conclude that the research on predicting faults in Python programs using machine learning techniques is worth conducting, natural ways to enhance the future research being: using more sophisticated machine learning techniques, using additional Python-specific features and extended data sets.

3

On dynamically consistent Jacobian inverse for non-holonomic robotic systems

Ratajczak J., Tchoń K.

Archives of Control Sciences

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2017

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Vol. 27, no. 4

555--573

EN

This paper presents the dynamically consistent Jacobian inverse for non-holonomic robotic system, and its application to solving the motion planning problem. The system’s kinematics are represented by a driftless control system, and defined in terms of its input-output map in accordance with the endogenous configuration space approach. The dynamically consistent Jacobian inverse (DCJI) has been introduced by means of a Riemannian metric in the endogenous configuration space, exploiting the reduced inertia matrix of the system’s dynamics. The consistency condition is formulated as the commutativity property of a diagram of maps. Singular configurations of DCJI are studied, and shown to coincide with the kinematic singularities. A parametric form of DCJI is derived, and used for solving example motion planning problems for the trident snake mobile robot. Some advantages in performance of DCJI in comparison to the Jacobian pseudoinverse are discovered.

4

Procedura ulepszania łańcucha dostaw firmy

Kochański T.

Gospodarka Materiałowa i Logistyka

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2016

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nr 5

357--369

PL

Łańcuchy dostaw mają znaczący udział w zapewnieniu pozycji konkurencyjnej firm na współczesnym rynku. Ciągłe jego ulepszanie korzystnie wpływa na redukcje zapasów i obniżenie kosztów oraz poprawę poziomu koordynacji i zaufania pomiędzy partnerami sieci dostaw, a także spełniania oczekiwań klientów. Jednym ze sposobów na zapewnienie skuteczności firm na obecnym konkurencyjnym i umiędzynarodowionym rynku, zdaniem autora jest przedstawiona w artykule procedura ulepszania ich łańcucha dostaw oraz jego synchronizacja. Wzrostu skuteczności działań usprawniających łańcuch dostaw należy także upatrywać w wykorzystywaniu wskaźników i mierników oraz technologii informatycznych. Nowoczesne technologie informatyczne umożliwiają kształtowanie skuteczności wskaźników i mierników łańcucha dostaw oraz szerszą optymalizację jego działań w sferze planowania, zarządzania i kontroli.

EN

Supply chains have a significant participation in ensuring the competitive position of companies on the contemporary market. Continuous improvement of supply chains has beneficial effects on the reduction of stocks, reduces costs and improves the level of coordination and trust between supply chain partners, as well as meets the expectations of customers. In author’s mind, one of methods to ensure the effectiveness of the companies in the existing competitive and internationalized market is presented below procedure of improvement for logistic supply chain and its synchronization. Growth effectiveness of activities which would improve the supply chain should also be perceived in the use of indicators and metrics, and technologies. Modern information technologies allow the development of effectiveness for indicators and metrics of the supply chain and the broader optimization its activities in the planning, management and control.

5

Product variety management as a tool for successful mass customized product structure

Bednar S., Modrak J.

Polish Journal of Management Studies

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2015

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Vol. 12, No. 1

16--25

EN

Successful and efficient product mix requires balancing process and market trade-offs. This is especially applicable in mass-customizable (MC) productions making products in number of configurations according to customers' preferences. Such a variety brings complexity into production processes as well as in product management level. This paper presents a methodology for quantifying product variety induced complexity (VIC) as a number of available product configurations in a case product line. The model of MC assembly product line is further optimized respecting a demand for products. Finally, mutual relations of the VIC metric before and after product line optimization are presented, what evidently justifies a usability of the VIC metric.

PL

Skuteczna oferta produktów wymaga procesu równoważenia i kompromisów rynku. Jest to szczególnie stosowane w masowo konfigurowalnych (MC) produkcjach wytwarzających produkty w wielu konfiguracjach, w zależności od preferencji klienta. Taka różnorodność wnosi kompleksowość do procesów produkcyjnych oraz na poziomie zarządzania produktem. Niniejszy artykuł przedstawia metodykę ilościowego określania różnorodności produktów indukowaną złożonością (VIC) jako liczbę dostępnych konfiguracji produktu w przypadku linii produktów. Model linii produktów montażu MC jest następnie optymalizowany uwzględniając popyt na produkty. Ostatecznie, przedstawione są wzajemne relacje metryki VIC przed i po optymalizacji linii produktów, co wyraźnie uzasadnia przydatność metryki VIC.

6

A method based on fuzzy system for assessing the reliability of software based aspects

Zavvar M, Ramezani F

Advances in Science and Technology. Research Journal

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2015

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Vol. 9, nr 27

143--148

EN

In fact, reliability as the qualities metric is the probability success or the probability that a system or a set of tasks will work without failure for a specified constraints of time and space, as specified in the design and operating conditions specified temperature, humidity, vibration and action. A relatively new methodologies for developing complex software systems engineering is an aspect oriented software systems, that provides the new methods for the separation of concerns multiple module configuration or intervention and automatic integration them with a system. In this paper, a method using fuzzy logic to measure software reliability based on the above aspects is presented. The proposed approach regarding the use of appropriate metrics and low errors in the estimation of reliability has a better performance than other methods.

7

Routing base congestion control metrics in manets

Dalal S., Ruhil R

Advances in Science and Technology. Research Journal

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2014

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Vol. 8, nr 23

33--40

EN

Mobile adhoc network is self-configurable and adaptive. Due to node mobility we cannot predict load on the network which leads to congestion, one of the widely researched area in manets. A lot of congestion control techniques and metrics have been proposed to overcome it before its occurrence or after it has occurred. In this survey we identify the currently used congestion control metrics. Through this survey we also propose a congestion control metric RFR(resource free ratio) which considers three most important parameters to provide congestion free route discovery. Further we show the results of node selection based on fuzzy logic calculations using the proposed metric.

8

Fixed point and homotopy results for generalized contractions on spaces with two metrics

Kiran Q., Kamran T.

Demonstratio Mathematica

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2010

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Vol. 43, nr 1

151-160

EN

In this paper, we establish fixed point and homotopic results for generalized contractions on spaces with two metrics. Our results generalize and extend the results of Agarwal and O 'Regan [R. P. Agarwal, Donal O 'Regan, Fixed point theory for generalized contractions on spaces with two metrics, J. Math. Anal. Appl. 248 (2000), 402-414] and those contain therein.

9

Metoda porównywania drzew filogenetycznych wykorzystująca najlżejsze doskonałe skojarzenie w grafach dwudzielnych

Bogdanowicz D.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

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2008

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T. 15

183-188

PL

Drzewa filogenetyczne przedstawiają historyczne, ewolucyjne związki pokrewieństwa między różnymi gatunkami lub różnymi osobnikami w ramach jednego gatunku. Istnieje wiele metod rekonstruowania drzew filogenetycznych. Wykorzystywanie różnych metod na tym samym zbiorze danych zazwyczaj owocuje powstaniem różnych drzew. Pojawia się zatem pytanie: jak bardzo dwa dane drzewa różnią się od siebie. W niniejszej pracy prezentujemy nową ogólną metodę porównywana drzew filogenetycznych. Metoda opiera się na wykorzystaniu najlżejszego doskonałego skojarzenia w grafach dwudzielnych i przy opisanych założeniach wymaga wielomianowego czasu obliczeń. W pracy omówiono podstawowe własności metryki oraz podano trzy przypadki szczególne. Przedstawiono także wyniki eksperymentów obliczeniowych.

EN

A phylogenetic tree represents historical evolutionary relationship between different species or organisms. There are various methods for reconstructing phylogenetic trees. Applying those techniques usually results in different trees for the same input data. An important problem is to determine how distant two trees reconstructed in such a way are from each other. In this paper, new metrics for comparing phylogenetics trees are suggested. These metrics are based on minimum weight perfect matching in bipartite graphs and can be computed in a polynomial time. We study same properties of these metrics and compare them with methods previously known.

10

The effective method of computing the soft-decision metrics in the system with quadrature amplitude modulation

Kliks A.

Poznan University of Technology Academic Journals. Electrical Engineering

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2007

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No 54

81-87

EN

The decision on a transmitted symbol is one of the key points in the decoding process of the received signal. The block of demapper, that is responsible for mapping of the constellation points to the binary blocks, produces either the binary data blocks or a set of metrics on its outputs. In this paper, the optimal iterative algorithm of finding the minimal set of metrics - when the data QAM symbols are coded with Grey code - is discussed. At the beginning, the description of OFDM systems and the channel influence on the data transmission in such systems are presented. Then, the main idea of finding metrics is described in detail. The obtained results are discussed and summarized in the conclusion.

11

Benchmarking image codecs by assessment of coded test images: the development of test images and new objective quality metrics

Punchihewa A., Bailey D. G., Hodgson R. M.

Journal of Telecommunications and Information Technology

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2006

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nr 1

11-16

EN

Objective quality measures are required for benchmarking codec performance. Our aim was to develop a simple, accurate method capable of rapidly measuring the degree of blockiness, edge-blur and ringing due to image compression. Two test images were designed to emphasise these artefacts. The efficacy of the new metrics is demonstrated using a JPEG codec at a range of compression levels.

12

Indexing Schemes for Similarity Search: an Illustrated Paradigm

Pestov V., Stojmirović A.

Fundamenta Informaticae

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2006

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Vol. 70, nr 4

367-385

EN

We suggest a variation of the Hellerstein-Koutsoupias-Papadimitriou indexability model for datasets equipped with a similarity measure, with the aim of better understanding the structure of indexing schemes for similarity-based search and the geometry of similarity workloads. This in particular provides a unified approach to a great variety of schemes used to index into metric spaces and facilitates their transfer to more general similarity measures such as quasi-metrics. We discuss links between performance of indexing schemes and high-dimensional geometry. The concepts and results are illustrated on a very large concrete dataset of peptide fragments equipped with a biologically significant similarity measure.

13

A Low-complexity Distance for DNA Strings

Dinu L.P., Sgarro A.

Fundamenta Informaticae

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2006

|

Vol. 73, nr 3

361-372

EN

We exhibit a low-complexity but non-trivial distance between strings to be used in biology. The experimental results we provide were obtained on a standard laptop and, even if preliminary, are quite encouraging.

14

Czas i względność

Dobrogowski A.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

|

2005

|

nr 5

176-182

PL

Efekty relatywistyczne stały się powodem rozróżnienia pomiędzy czasem własnym i czasem koordynatowym. Metryka Minkowskiego czasoprzestrzeni pozwala stwierdzić wydłużenie czasu w przemieszczających się układach inercjalnych. Geometria czasoprzestrzeni Riemanna indentyfikuje wpływ potencjału grawitacyjnego i dośrodkowego na bieg czasu oraz efekt Sagnaca. Przedyskutowano synchronizację koordynatową zegarów.

EN

Relativistic effects forced the introducing of differentiation between proper and coordinate time. Spacetime of Minkowski metric makes it possible to investigate time dilation in moving inertial frames. Riemann's geometry of spacetime identifies the influence of gravitational and centrifugal potentials on time as well as Sagnac effect. Coordinate synchronization of clocks is discussed.

15

Shape identification via metrics constructed from the oriented distance function

Delfour M. C., Zolesio J.-P.

Control and Cybernetics

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2005

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Vol. 34, no 1

137-164

EN

This paper studies the generic identification problem: to find the best non-parametrized object [Omega] which minimizes some weighted sum of distances to I a priori given objects [Omega]_i for metric distances constructed from the W^1,p-norm on the oriented (resp. signed) distance function which occurs in many different fields of applications. It discusses existence of solution to the generic identification problem and investigates the Eulerian shape semiderivatives with special consideration to the non-differentiable terms occurring in their expressions. A simple example for the new cracked sets recently introduced in Delfour and Zolesio (2004b) is also presented. It can be viewed as an approximation of a cracked set by sets whose boundary is made up of pieces of lines or Bezier curves that are not necessarily connected.

16

Geodesy and connectivity in lattices

Ronse Ch., Serra J.

Fundamenta Informaticae

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2001

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Vol. 46, nr 4

349-395

EN

This paper generalizes the notion of symmetrical neighbourhoods, which have been used to define connectivity in the case of sets, to the wider framework of complete lattices having a sup-generating family. Two versions (weak and strong) of the notion of a symmetrical dilation are introduced, and they are applied to the generation of ``connected components'' from the so-called ``geodesic dilations''. It turns out that any ``climbing'' ``weakly symmetrical'' extensive dilation induces a ``geodesic'' connectivity. When the lattice is the one of subsets of a metric space, the connectivities which are obtained in this way may coincide with the usual ones under some conditions, which are clarified. The abstract theory can be applied to grey-level and colour images, without any assumption of translation-invariance of operators.

17

On linear operators extending [pseudo]metrics

Banach T., Bessaga C.

Bulletin of the Polish Academy of Sciences. Mathematics

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2000

|

Vol. 48, no 1

35-49

EN

For every closed subset X of a stratifiable [respectively metrizable] space Y we construct a positive linear extension operator T : R[sup X*X] --> R[sup Y*Y] preserving constant functions, bounded functions, continuous functions, pseudometrics, metrics, [respectively dominating metrics, and admissible metrics]. This operator is continuous with respect to each of the three topologies : point-wise convergence, uniform, and compact-open. An equivariant analog of the above statement is proved as well.