Wyniki wyszukiwania - BazTech

1

Running a workflow without workflows: a basic algorithm for dynamically constructing and traversing an implied Directed Acyclic Graphin a non-deterministic environment

Smilianets Fedir, Finogenov Oleksii

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2024

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T. 14, nr 1

115--118

EN

This paper introduces a novel algorithm for dynamically constructing and traversing Directed Acyclic Graphs (DAGs) in workflow systems, particularly targeting distributed computation and data processing domains. Traditional workflow managementsystems rely on explicitly defined, rigid DAGs, which can be cumbersome to maintain, especially in response to frequent changes or updates in the system. Our proposed algorithm circumvents the need for explicit DAG construction, instead opting for a dynamic approach that iteratively builds and executes the workflow based on available data and operations, through a combination of entities like Data Kinds, Operators, and Data Units, the algorithm implicitly forms a DAG, thereby simplifying the process of workflow management. We demonstrate the algorithm’s functionality and assess its performance through a series of tests in a simulated environment. The paper discusses the implications of this approach, especially focusing on cycle avoidance and computational complexity, and suggests future enhancements and potential applications.

PL

W artykule przedstawiono nowy algorytm dynamicznego konstruowania i przejść skierowanych grafów acyklicznych (DAG) w systemach zarządzania przepływem pracy, w szczególności tych ukierunkowanych na domeny obliczeń rozproszonych i przetwarzania danych. Tradycyjne systemy zarządzania przepływem pracy opierają się na jawnie zdefiniowanych, sztywnych grafach DAG, które mogą być uciążliwe w utrzymaniu, zwłaszczaw odpowiedzi na częste zmiany lub aktualizacje systemu. Proponowany algorytm pozwala uniknąć konieczności jawnego konstruowania SAG, zamiast tego wybierając dynamiczne podejście, które iteracyjnie buduje i wykonuje przepływy pracy w oparciu o dostępne dane i operacje. Korzystając z kombinacji jednostek, takich jak typ danych, operator i element danych, algorytm niejawnie buduje DAG, upraszczając w ten sposób proces zarządzania przepływami pracy. Demonstrujemy funkcjonalność algorytmu i oceniamy jego wydajność za pomocą serii testów w symulowanym środowisku. W artykule omówiono implikacje tego podejścia, ze szczególnym uwzględnieniem unikania pętli i złożoności obliczeniowej, a także zasugerowano dalsze ulepszenia i potencjalne zastosowania.

2

Downtime Measurements of Generator-Powered Microgrid During Planned and Unplanned Transfer to Island Mode

Prokop Kamil, Bień Andrzej, Barczentewicz Szymon

International Journal of Electronics and Telecommunications

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2023

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Vol. 69, No. 3

493--498

EN

Growing popularity of distributed generation is drawing special attention to communication technologies in smart power grids. This paper provides a detailed overview of the communication protocols utilized in the modern distributed grid laboratory. It describes both wired and wireless technologies used in Smart Grid and presents the remote operation of switching the subsystem from grid mode to island mode operating under nominal conditions. It shows the duration of power outages during a transfer to island mode with diesel generator running on idle - which simulates planned islanding and diesel generator stationary, which simulates unplanned islanding. Latency between registration of disturbance and executing control command is measured. The results obtained are compared with current legislation. The consequences to the power system that are possible in both scenarios are highlighted. Obtained results and description of the communication technologies can be useful for the design of distributed power grids, island-mode power grids, and Smart Grids, as well as for further research in the area of using combustion fuel generators as a primary power supply in the microgrid.

3

Distributed accelerated projection - based consensus decomposition

Maj Wiktor

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2022

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Vol. 26, No 2

32--38

EN

With the development of machine learning and Big Data, the concepts of linear and non-linear optimization techniques are becoming increasingly valuable for many quantitative disciplines. Problems of that nature are typically solved using distinctive optimization algorithms, iterative methods, or heuristics. A new variant of the Accelerated Projection-Based Consensus (APC) iterative method is proposed, which is faster than its classical version while handling large sparse matrices in distributed settings. The algorithm is proposed, and its description and implementation in a high-level programming language are presented. Convergence tests measuring acceleration factors based on real-world datasets are done, and their results are promising. The results of this research can be used as an alternative to solving numerical optimization problems.

4

A distributed algorithm for protein identification from tandem mass spectrometry data

Orzechowska Katarzyna, Rubel Tymon, Kurjata Robert, Zaremba Krzysztof

Applied Computer Science

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2022

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Vol. 18, no 2

16--27

EN

Tandem mass spectrometry is an analytical technique widely used in proteomics for the high-throughput characterization of proteins in biological samples. Modern in-depth proteomic studies require the collection of even millions of mass spectra representing short protein fragments (peptides). In order to identify the peptides, the measured spectra are most often scored against a database of amino acid sequences of known proteins. Due to the volume of input data and the sizes of proteomic databases, this is a resource-intensive task, which requires an efficient and scalable computational strategy. Here, we present SparkMS, an algorithm for peptide and protein identification from mass spectrometry data explicitly designed to work in a distributed computational environment. To achieve the required performance and scalability, we use Apache Spark, a modern framework that is becoming increasingly popular not only in the field of “big data” analysis but also in bioinformatics. This paper describes the algorithm in detail and demonstrates its performance on a large proteomic dataset. Experimental results indicate that SparkMS scales with the number of worker nodes and the increas-ing complexity of the search task. Furthermore, it exhibits a protein identification efficiency comparable to X!Tandem, a widely-used proteomic search engine.

5

Circle formation by asynchronous opaque robots on infinite grid

Adhikary Ranendu, Kundu Manash Kumar, Sau Buddhadeb

Computer Science

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2021

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T. 22 (1)

81-100

EN

This paper presents a distributed algorithm for the Circle Formation problem under the infinite grid environment by asynchronous mobile opaque robots. Initially, all of the robots acquire distinct positions, and they must form a circle over the grid. The movements of the robots are only restricted along the grid lines; they do not share any global coordinate system. The robots are controlled by an asynchronous adversarial scheduler that operates in Look-Compute-Move cycles. The robots are indistinguishable by their nature, and they do not have any memory of their past configurations nor previous actions. We consider the problem under a luminous model, where robots communicate via lights; other than that, they do not have any external communication systems. Our protocol solves the Circle Formation problem using seven colors. A subroutine of our algorithm also solves the Line Formation problem using three colors.

6

Wykorzystanie własnych zasobów obliczeniowych przedsiębiorstwa w procesie planowania produkcji

Dłubacz W., Duda J.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Technika, Informatyka, Inżynieria Bezpieczeństwa

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2018

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T. 6

355--369

PL

W artykule przedstawiony został nowoczesny system obliczeń rozproszonych, umożliwiający łatwe wykorzystanie dostępnych zasobów obliczeniowych przedsiębiorstwa. Opracowany system pozwala na przygotowanie planów produkcji w oparciu o różne modele matematyczne. Do rozwiązania problemów został wykorzystany rozproszony algorytm genetyczny z różnymi reprezentacjami chromosomu oraz operatorami genetycznymi, dostosowanymi do specyfiki danego problemu. W ten sposób wykazana została uniwersalność zaproponowanego systemu i jego zdolność do rozwiązywania rzeczywistych problemów zarządzania produkcją.

EN

The article presents a modern system of distributed computing, allowing easy use of available computational resources of the company. The developed system allows for the generation of production plans based on various mathematical models. A distributed genetic algorithm with different solution representations and different genetic operators tailored to the specific problem is used to solve the problems. In this way, the universality of the proposed system and its ability to solve real problems of production management were demonstrated.

7

A distributed method for transient simulations that dynamically considers supplementary results from autonomous software agents

Jüttner M., Grabmaier S., Rohloff J., Vögeli D., Rucker W. M., Göhner P., Weyrich M.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2018

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T. 8, nr 2

35--38

EN

Based on autonomous software agents capable of calculating individual numerical field problems, a distributed method for solving transient field problems is presented. The software agents are running on distributed resources connected via a network and represent a dynamic calculation environment. Communication and data exchange between multiple agents enables their collaboration and allows decisions based on distributed overall knowledge. As unique characteristics, no central unit influences the solution process at any time. The presented simulation example and its evaluated calculation process proves the method to benefit from redundant resources.

PL

W oparciu o autonomiczne agenty programowe zdolne do obliczania indywidualnych numerycznych problemów pola, przedstawiono rozproszoną metodę rozwiązywania stanów przejściowych pola. Agenty programowe działają na zasobach rozproszonych połączonych za pośrednictwem sieci i reprezentują środowisko obliczeń dynamicznych. Komunikacja i wymiana danych między wieloma agentami umożliwia ich współpracę i pozwala podejmować decyzje w oparciu o rozproszoną wiedzę ogólną. Jako unikalna charakterystyką jest fakt, że żadna jednostka centralna nie wpływa w żadnym momencie na proces rozwiązania. Przedstawiony przykład symulacji i jej oszacowany proces obliczeniowy dowodzi, że metoda umożliwia korzystanie z nadmiarowych zasobów.

8

Distributed mesh generation for objects with shape variability

Poławski B., Sawicki B.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 12

143--146

EN

The article presents an efficient way to generate a large number of finite element meshes to support statistical analysis of simulation of electromagnetic field inside biological objects which are characterized by a strong shape variability. Demonstrated solution uses capabilities of modern distributed computer systems and open source software. Parametric model of a hen egg has been used as a simple biological object to test the developed solution.

PL

Praca przedstawia efektywną metodę generowania wielu siatek elementów skończonych dla potrzeb modelowania pola elektromagnetycznego w obiektach o pochodzeniu biologicznym charakteryzujących się dużą zmiennością kształtu i ich statystycznej analizy. Do rozwiązania problemu zostały wykorzystane możliwości nowoczesnych systemów informatycznych o architekturze rozproszonej i otwartozródłowego oprogramowania. Do celów testów zaproponowanego rozwiązania został stworzony parametryczny model kurzego jaja jako przykład prostego obiektu biologicznego.

9

Mobile Cloud for Parallel and Distributed Green Computing

Siwik L., Kala D., Godzik M., Turek W., Byrski A., Kisiel-Dorohinicki M.

Journal of Telecommunications and Information Technology

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2017

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nr 4

60--70

EN

Mobile Computing and Mobile Cloud Computing are the areas where intensive research is observed. The “mobility” landscape (devices, technologies, apps, etc.) evolves so fast that deﬁnitions and taxonomies do not catch up with so dynamic changes and there is still an ambiguity in deﬁnitions and common understanding of basic ideas and models. This research focuses on Mobile Cloud understood as parallel and distributed system consisting of a collection of interconnected (and virtualized) mobile devices dynamically provisioned and presented as one uniﬁed computing resource. This paper focuses on the mobile green computing cloud applied for parallel and distributed computations and consisting of outdated, abandoned or no longer needed smartphones being able to set up a powerful computing cluster. Besides showing the general idea and background, an actual computing cluster is constructed and its scalability and efficiency is checked versus the results obtained from the virtualized set of smartphones. All the experiments are performed using a dedicated software framework constructed in order to leverage the nolonger-needed smartphones, creating a computing cloud.

10

Volunteer computing in a scalable lightweight web-based environment

Chorazyk P., Byrski A., Pietak K., Kisiel-Dorohinicki M., Turek W.

Computer Assisted Methods in Engineering and Science

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2017

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Vol. 24, no. 1

17--40

EN

Volunteer computing is a very appealing way of utilizing vast available resources in efficient way. However, the current platforms that support such computing style are either difficult to use or not available at all, as a results of finished scientific projects, for example. In this paper, a novel lightweight volunteer computing platform is presented and thoroughly tested in an artificial environment of a commercially available computing cloud using two computing-related tasks and one web-crawling-related task.

11

Cellular automata model for prediction of crack initiation and propagation in hot forging tools

Rauch L., Chmura A., Gronostajski Z., Polak S., Pietrzyk M.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 3

437--447

EN

The paper presents design and implementation of the cellular automata (CA) model, which predicts damage of forging tools due to fatigue. The transition rules for the model were developed on the basis of known information regarding crack initiation and propagation. The coefficients in the model were determined by the inverse analysis of the thermal fatigue tests performed on the Gleeble 3800 simulator and in the special device with a rotating disc. The CA model was coupled with the conventional abrasive wear model. The layers of cell in the CA space, which are in contact with the workpiece, were removed successively following the abrasive wear of the tool. The CA model was connected with the finite element (FE) programme, which simulates stresses in tools during forging. Since this multiscale approach appeared to be extremely demanding as far as computing times are considered, an efficient implementation of the model on heterogeneous hardware architectures was prepared. Results of simulations were compared with the industrial data and good predictive capabilities of the model were confirmed.

12

Zastosowanie systemów rozproszonych w wizualizacjach 3D

Bundyra M., Wiciak J.

Prace Instytutu Mechaniki Górotworu PAN

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2015

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Vol. 17, no. 1-2

41--48

PL

W artykule zaprezentowana została metodyka projektowania oraz implementacji rozproszonego systemu obliczeniowego na przykładzie obliczeń animacji 3D w programie Blender. Zaproponowany system w założeniach ma być uniwersalny, skalowalny oraz niewymagający konfi guracji przez użytkownika. Jego działanie ma opierać się na nieodpłatnym wykorzystaniu udostępnionych zasobów obliczeniowych. System zaprojektowano w oparciu wykorzystanie darmowych narzędzi opartych na licencji GNU GPL oraz darmowego systemu operacyjnego Linux. Zaproponowane w artykule rozwiązanie stanowi alternatywę dla komercyjnych, zamkniętych rozwiązań.

EN

In this paper the methodology of design and implementation of distributed computing system based on an example of 3D visualization is introduced. The proposed system is supposed to be universal, scalable and user-friendly. The system depends on users who free of charge share their computing power. The solution has been designed to rely on free license software and costless operating system Linux. The proposed in the article solution is a great alternative of closed, commercial computing systems.

13

Performing acoustic localization in a network of embedded smart sensors

Astapov S., Ehala J., Preden J.-S.

International Journal of Microelectronics and Computer Science

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2015

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Vol. 6, nr 3

86--95

EN

Situation awareness is an important aspect of ubiquitous computer systems, as these systems of systems are highly integrated with the physical world and for successful operation they must maintain high awareness of the environment. Acoustic information is one of the most popular modalities, by which the environment states are estimated. Multi-sensor approaches also provide the possibility for acoustic source localization. This paper considers an acoustic localization system of dual channel smart sensors interconnected through a Wireless Sensor Network (WSN). The low computational power of smart sensor devices requires distribution of localization tasks among WSN nodes. The Initial Search Region Reduction (ISRR) method is used in the WSN to meet this requirement. ISRR, as opposed to conventional localization methods, performs significantly less complex computations and does not require exchange of raw signal between nodes. The system is implemented on smart dust motes utilizing Atmel ATmega128RFA1 processors with integrated 2.4GHz IEEE 802.15.4 compliant radio transceivers. The paper discusses complications introduced by low power hardware and ad-hoc networking, and also reviews conditions of real-time operation.

14

Process Discovery and Conformance Checking Using Passages

van der Aalst W. M. P., Verbeek H. M. W.

Fundamenta Informaticae

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2014

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Vol. 131, nr 1

103--138

EN

The two most prominent process mining tasks are process discovery (i.e., learning a process model from an event log) and conformance checking (i.e., diagnosing and quantifying differences between observed and modeled behavior). The increasing availability of event data makes these tasks highly relevant for process analysis and improvement. Therefore, process mining is considered to be one of the key technologies for Business Process Management (BPM). However, as event logs and process models grow, process mining becomes more challenging. Therefore, we propose an approach to decompose process mining problems into smaller problems using the notion of passages. A passage is a pair of two non-empty sets of activities (X, Y) such that the set of direct successors of X is Y and the set of direct predecessors of Y is X. Any Petri net can be partitioned using passages. Moreover, process discovery and conformance checking can be done per passage and the results can be aggregated. This has advantages in terms of efficiency and diagnostics. Moreover, passages can be used to distribute process mining problems over a network of computers. Passages are supported through ProM plug-ins that automatically decompose process discovery and conformance checking tasks.

15

On the π-calculus and Co-intuitionistic Logic : Notes on Logic for Concurrency and λP Systems

Bellin G., Menti A.

Fundamenta Informaticae

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2014

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Vol. 130, nr 1

21--65

EN

We reconsider work by Bellin and Scott in the 1990s on R. Milner and S. Abramsky’s encoding of linear logic in the π-calculus and give an account of efforts to establish a tight connection between the structure of proofs and of the cut elimination process in multiplicative linear logic, on one hand, and the input-output behaviour of the processes that represent them, on the other, resulting in a proof-theoretic account of (a variant of) Chu’s construction. But Milner’s encoding of the linear lambda calculus suggests consideration of multiplicative co-intuitionistic linear logic: we provide a term assignment for it, a calculus of coroutines which presents features of concurrent and distributed computing. Finally, as a test case of its adequacy as a logic for distributed computation, we represent our term assignment as a λP system. We argue that translations of typed functional languages in concurrent and distributed systems (such as π-calculi or λP systems) are best typed with co-intuitionistic logic, where some features of computations match the logical properties in a natural way.

16

Efficient implementation of branch-and-bound method on desktop grids

Tlan B., Posypkin M.

Computer Science

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2014

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Vol. 15 (3)

239--252

EN

The Berkeley Open Infrastructure for Network Computing (BOINC) is an open-source middleware system for volunteer and desktop grid computing. In this paper, we propose BNBTEST, a BOINC version of the distributed branch-and-bound method. The crucial issues of the distributed branch-and-bound method are traversing the search tree and loading the balance. We developed a subtask packaging method and three different subtask distribution strategies to solve these.

17

Efficient cellular automata model for prediction of damage of hot forging tools due to thermal fatigue

Nowak P., Rauch Ł.

Computer Methods in Materials Science

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2014

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Vol. 14, No. 4

197--205

EN

W pracy przedstawiono implementację modelu automatów komórkowych (ang. Cellular Automata - CA) przewidującego rozwój pękania zmęczeniowego w narzędziach do kucia na gorą¬co. Reguły przejścia opracowano na bazie dostępnych informacji dotyczących inicjacji i propagacji pęknięć. Współczynniki modelu wyznaczono na podstawie prób zmęczeniowych przeprowadzo¬nych na symulatorze Gleeble 3800. Model CA połączono z pro¬gramem MES, który symuluje naprężenia podczas kucia. To wieloskalowe podejście jest bardzo wymagające obliczeniowo. Dlatego efektywna równoległa implementacja tego modelu była głównym celem pracy. Model pękania zmęczeniowego zrealizowano w technice GPGPU, co ułatwiło implementację algorytmów za pomocą udostępnienia API (z j. ang. Application Programming Interface) dostarczającego funkcje z biblioteki OpenGL. Platformę wspoma-gającą obliczenia CA podzielono na części biblioteczną i aplika¬cyjną. Biblioteka dostarcza API do obsługi jądra programu w technologii OpenGL dedykowanego na akceleratory oblicze¬niowe CPU i GPU. Aplikacyjna część wykorzystuje API dostar¬czone przez bibliotekę i jej zadaniem jest przekazanie i zarządza¬nie parametrami wejściowymi do obliczeń. Zadaniem aplikacji jest również stworzenie wejściowej przestrzeni automatów ko¬mórkowych, wczytanie i ustawienie wartości wewnętrznych komórek CA oraz przekazanie ich do obliczeń na akceleratorach. W pracy opisano implementację modelu oraz przedstawiono przykładowy wynik symulacji pęknięć w matrycy kuźniczej. Dzięki zrównolegleniu algorytmu i wykorzystaniu czterech kart GPU uzyskano wysokie przyspieszenie obliczeń przy dobrej skalowalności.

18

Zastosowanie technologii OpenCLl w systemie zadań rozproszonych w architekturze nadzorca-wykonawca

Wyciślik Ł., Kulig Ł.

Studia Informatica

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2013

|

Vol. 34, nr 2B

283--292

PL

Artykuł opisuje zastosowanie technologii OpenCL do wykonywania obliczeń z wykorzystaniem procesora graficznego w systemie rozproszonym. Zastosowanie technologii OpenCL pozwoliło na wykorzystanie dowolnej jednostki obliczeniowej danej stacji roboczej (zarówno GPU, jak i CPU). Stworzony system jest elastyczny i pozwala na zmianę implementacji OpenCL.

EN

This article describes the usage of OpenCL technology to perform computations with usage of GPU in the task distribution system. Usage of OpenCL technology allowed to involve any kind of workstation’s processing unit (GPU, CPU). This system is flexible and allows to change the OpenCL implementation.

19

From quantity to quality: massive molecular dynamics simulation of nanostructures under plastic deformation in desktop and service grid distributed computing infrastructure

Gatsenko O., Bekenev L., Pavlov E., Gordienko Y. G.

Computer Science

|

2013

|

Vol. 14 (1)

27--44

EN

The distributed computing infrastructure (DCI) on the basis of BOINC and EDGeS-bridge technologies for high-performance distributed computing is used for porting the sequential molecular dynamics (MD) application to its parallel version for DCIwith Desktop Grids (DGs) and Service Grids (SGs). The actual metrics of the working DG-SG DCI were measured, and the normal distribution of host performances, and signs of log-normal distributions of Rother characteristics (CPUs, RAM, and HDD per host) were found. The practical feasibility and high efficiency of the MD simulations on the basis of DG-SG DCI were demonstrated during the experiment with the massive MD simulations for the large quantity of aluminum nanocrystals (Statistical analysis (Kolmogorov-Smirnov test, moment analysis, and bootstrapping analysis) of the defect density distribution over the ensemble of nanocrystals had show that change of plastic deformation mode is followed by the qualitative change of defect density distribution type over ensemble of nanocrystals. Some limitations (fluctuating performance, unpredictable availability of resources, etc.) of the typical DG-SG DCI were outlined, and some advantages (high efficiency, high speedup, and low cost) were demonstrated. Deploying on DG DCI allows to get new scientific quality from the simulated quantity of numerous configurations by harnessing sufficient computational power to undertake MD simulations in a wider range of physical parameters (configurations) in a much shorter timeframe.

20

Building science gateways by utilizing the generic WS-PGRADE/gUSE workflow system

Balasko A., Farkas Z., Kacsuk P.

Computer Science

|

2013

|

Vol. 14 (2)

307--325

EN

Enabling scientists to use remote distributed infrastructures, parametrize and execute common science-domain applications transparently is actual and a highly relevant field of distributed computing. For this purpose a general solution is the concept of Science Gateways. WS-PGRADE/gUSE system offers a transparent and web-based interface to access distributed resources (grids, clusters or clouds), extended by a powerful generic purpose workflow editor and enactment system, which can be used to compose scientific applications into data-flow based workflow structures. It’s a generic web-based portal solution to organize scientific applications in a workflow structure and execute them on remote computational resources. As the portal defines nodes as black-box applications uploaded by the users, it does not provide any application specific interface by default. In this paper we show what kind of tools, APIs and interfaces are available in WS-PGRADE/gUSE to customize it to have an application specific gateway.