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Katedra Architektury Systemów Komputerowych
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wszystkich: 841
Katalog Publikacji
Rok 2011
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0-step K-means for clustering Wikipedia search results
PublikacjaThis article describes an improvement for K-means algorithm and its application in the form of a system that clusters search results retrieved from Wikipedia. The proposed algorithm eliminates K-means isadvantages and allows one to create a cluster hierarchy. The main contributions of this paper include the ollowing: (1) The concept of an improved K-means algorithm and its application for hierarchical clustering....
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A New Model for context aware applications analysis and design
PublikacjaW artykule zostały opisane aplikacje kontekstowe, które działają w przestrzeniach inteligentnych, oraz zostały przeanalizowane ich właściwości. Na podstawie analizy zaproponowano nowe podejście do ich modelowania które zapewnia oddzielenie logiki aplikacji w zakresie adaptacji (do zmian środowiska) od jej realizacji. Zostały wykorzystane MVC i modele zmian stanu. Zaproponowano ilościową miarę poziomu kontekstowości a także sposób...
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A proposition for integrating elements of game universe by means of behavioral trees
PublikacjaModern computer games often involve autonomous beings collaborating and competing with each other to reach their objectives in the game universe. It seems only natural to use agent-oriented approach in such cases. This article identifies the rules of building a game universe as an environment for executing agents. The paper also covers a method for decomposing compound behaviors into behavioral trees. Dividing complex behaviors...
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Agile Methodology for Designing and Improving EnterpriseScenarios
PublikacjaPrzedstawiona została iteracyjna metoda projektowania i ulepszania scenariuszy biznesowych. Zaproponowana metoda definiuje etapy wytwarzania scenariuszy, zestaw metryki oceny jakości scenariuszy oraz zestaw procedur usprawnieniowych, które pozwalają zwiększyć wydajność scenariuszy, ich jakość oraz użyteczność. Proste studium przypadku zostało rozważane i jego ocena jakościowo-wydajnościowa omówiona. Jako przykład realizacji metody...
Rok 2012
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A Clustering-Based Methodology for Selection of Fault Tolerance Techniques
PublikacjaDevelopment of dependable applications requires selection of appropriate fault tolerance techniques that balance efficiency in fault handling and resulting consequences, such as increased development cost or performance degradation. This paper describes an advisory system that recommends fault tolerance techniques considering specified development and runtime application attributes. In the selection process, we use the K-means...
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A Developer's View of Application Servers Interoperability
PublikacjaThe paper describes analysis of application servers interoperability that considers both the available level of integration and the required level of development complexity. Development complexity ranges from simple GUI operations to changes of undocumented features in configuration files. We verify if an integration can be established on a given level of development complexity, rather than verify if it is objectively feasible....
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A Parallel Genetic Algorithm for Creating Virtual Portraits of Historical Figures
PublikacjaIn this paper we present a genetic algorithm (GA) for creating hypothetical virtual portraits of historical figures and other individuals whose facial appearance is unknown. Our algorithm uses existing portraits of random people from specific historical period and social background to evolve a set of face images potentially resembling the person whose image is to be found. We then use portraits of the person's relatives to judge...
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A Ubiquitous System Using Semantic Knowledge in Dynamic Service Integration
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Adaptive Algorithm for Interactive Question-based Search
PublikacjaPopular web search engines tend to improve the relevanceof their result pages, but the search is still keyword-oriented and far from "understanding" the queries' meaning. In the article we propose an interactive question-based search algorithm that might come up helpful for identifying users' intents. We describe the algorithm implemented in a form of a questions game. The stress is put mainly on the most critical aspect of this...
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An Overview of the Development of a Real-Time System for Endoscopic Video Classification
PublikacjaThe article presents the results of improving endoscopic image classification algorithms in an effort towards applying them in a real-time diagnosis supporting system. Methods for the detection and removal of personal data are presented and discussed. The currently developed recognition algorithms have been improved in terms of accuracy and performance to make them suitable for a real-life implementation. Their test results are...
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Analiza istniejących obliczeń uruchamianych w systemach rozproszonych
PublikacjaZaprezentowano analizę algorytmów równoległych tradycyjnie uruchamianych w systemach klastrowych wysokiej wydajności, a następnie pokazano charakterystykę algorytmów ze względu na parametry istotne przy implementacji ich rozwiązań w rozproszonym środowisku Comcute. Następnie przedstawiono ocenę możliwości ich przeniesienia do tego środowiska.
Rok 2013
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A Concept of Modeling and Optimization of Applications in Large Scale Systems
PublikacjaThe chapter presents the idea that includes modeling and subsequent optimization of application execution on large scale parallel and distributed systems. The model considers performance, reliability and power consumption. It should allow easy modeling of various classes of applications while reflecting key parameters of both the applications and two classes of target systems: clusters and volunteer based systems. The chapter presents...
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A model, design, and implementation of an efficient multithreaded workflow execution engine with data streaming, caching, and storage constraints
PublikacjaThe paper proposes a model, design, and implementation of an efficient multithreaded engine for execution of distributed service-based workflows with data streaming defined on a per task basis. The implementation takes into account capacity constraints of the servers on which services are installed and the workflow data footprint if needed. Furthermore, it also considers storage space of the workflow execution engine and its cost....
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A ROLE PLAYING GAME NAME GENERATOR LEARNING ITS CREATIVITY FROM ARKADIA MUD PLAYERS
PublikacjaThe paper proposes an approach to creative generation of new names for the purposes of Role Playing Games in fantasy realms. The generator based on an existing database of na mes is able to propose a set of new names with regard to demanded attributes, such as: length of the name, sex and race of the character, a given p hrase as the origin for the generated name as well as subjective evaluations from former users. The software...
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Adjusting Game Difficulty by Recreating Behavioral Trees of Human Player Actions
PublikacjaThis paper presents a proposition of a method for adjusting game difficulty to the current level of player's skills in one-on-one games. The method is based on recognition of human player's actions and recording of those actions in the form of behavioral trees. Such trees are later used to drive behaviors of computer-controlled opponents so that human player has beat hit own strategy and improve on it, to win subsequent games....
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Algorytmy rozpoznawania zmian chorobowych
PublikacjaW pracy przedstawiono, opisano i porównano pod wzgledem skutecznosci wybrane algorytmy rozpoznawania chorób w filmach endoskopowych, zaimplementowane w ramach aplikacji Wspomagania Badan Medycznych. Dokonano oceny algorytmów w zaawansowanym srodowisku testowym, zbudowanym w oparciu o duzy zbiór obrazów z filmów endoskopowych, pozyskanych we współpracy z Gdanskim Uniwersytetem Medycznym. Jednoczesnie zaprezentowano sposób optymalizacji...
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An Evaluation Engine for Dynamic Ranking of Cloud Providers
PublikacjaThe paper focuses on creation of an effective dynamic ranking service for IaaS, PaaS and SaaS cloud providers. It considers building a quality model for this purpose along with definition of quality measure- ment procedures. The paper discusses several techniques known from already existing price comparison engines that could be modified and adopted for comparison of cloud providers. A technique for filtering measured data is proposed,...
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An Overview of Image Analysis Techniques in Endoscopic Bleeding Detection
PublikacjaAuthors review the existing bleeding detection methods focusing their attention on the image processing techniques utilised in the algorithms. In the article, 18 methods were analysed and their functional components were identified. The authors proposed six different groups, to which algorithms’ components were assigned: colour techniques, reflecting features of pixels as individual values, texture techniques, considering spatial...
Rok 2017
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A distributed system for conducting chess games in parallel
PublikacjaThis paper proposes a distributed and scalable cloud based system designed to play chess games in parallel. Games can be played between chess engines alone or between clusters created by combined chess engines. The system has a built-in mechanism that compares engines, based on Elo ranking which finally presents the strength of each tested approach. If an approach needs more computational power, the design of the system allows...
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An IoT-Based Computational Framework for Healthcare Monitoring in Mobile Environments
PublikacjaThe new Internet of Things paradigm allows for small devices with sensing, processing and communication capabilities to be designed, which enable the development of sensors, embedded devices and other ‘things’ ready to understand the environment. In this paper, a distributed framework based on the internet of things paradigm is proposed for monitoring human biomedical signals in activities involving physical exertion. The main...
Rok 2016
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A Fail-Safe NVRAM Based Mechanism for Efficient Creation and Recovery of Data Copies in Parallel MPI Applications
PublikacjaThe paper presents a fail-safe NVRAM based mechanism for creation and recovery of data copies during parallel MPI application runtime. Specifically, we target a cluster environment in which each node has an NVRAM installed in it. Our previously developed extension to the MPI I/O API can take advantage of NVRAM regions in order to provide an NVRAM based cache like mechanism to significantly speed up I/O operations and allow to preload...
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A Parallel MPI I/O Solution Supported by Byte-addressable Non-volatile RAM Distributed Cache
PublikacjaWhile many scientific, large-scale applications are data-intensive, fast and efficient I/O operations have become of key importance for HPC environments. We propose an MPI I/O extension based on in-system distributed cache with data located in Non-volatile Random Access Memory (NVRAM) available in each cluster node. The presented architecture makes effective use of NVRAM properties such as persistence and byte-level access behind...
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Adaption of Open Science Paradigm at Gdańsk University of Technology
PublikacjaThe paper describes the basic principles standing behind Open Access and will try to dispel the doubts behind them. Further the solution adapted by the Gdańsk University of Technology is presented. Later on the systems that the University uses and means of their integration into a complex Open Science platform are described. Finally the procedures needed to publish a document in the repository alongside the University's policy...
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Alternative Modeling of Volunteer Based Systems
PublikacjaThe canonical approach to model a flow of a voluntary based computing, as presented in Chapter 7 may tax the capacity of the simulator, especially when a more complex model of Voluntary Computing, proposed in [1], is used which would imply that, for typical heterogeneous groups of volunteers, several thousands of threads would have to be run inside the simulator, to mimic closely the behaviour of every volunteer. This chapter presents...
Rok 2023
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A Formal Approach to Model the Expansion of Natural Events: The Case of Infectious Diseases
PublikacjaA formal approach to modeling the expansion of natural events is presented in this paper. Since the mathematical, statistical or computational methods used are not relevant for development, a modular framework is carried out that guides from the external observation down to the innermost level of the variables that have to appear in the future mathematical-computational formalization. As an example we analyze the expansion of Covid-19....
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A multithreaded CUDA and OpenMP based power‐aware programming framework for multi‐node GPU systems
PublikacjaIn the paper, we have proposed a framework that allows programming a parallel application for a multi-node system, with one or more GPUs per node, using an OpenMP+extended CUDA API. OpenMP is used for launching threads responsible for management of particular GPUs and extended CUDA calls allow to manage CUDA objects, data and launch kernels. The framework hides inter-node MPI communication from the programmer who can benefit from...
Rok 2014
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A Human Behaviour Model Agent for Testing of Voluntary Computing Systems
PublikacjaPaper presents a design and performance of a voluntary-based distributed computing system testing agent, implementing a human behaviour model. The agent, nicknamed iRobot, was designed and implemented to enable controlled, large scale testing of core algorithms of Comcute - a new voluntary distributed computing platform complementary to BOINC. The main agent design goals were: emulation of human behaviour when browsing web pages,...
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A Model-Driven Solution for Development of Multimedia Stream Processing Applications
PublikacjaThis paper presents results of action research related to model-driven solutions in the area of multimedia stream processing. The practical problem to be solved was the need to support application developers who make their multimedia stream processing applications in a supercomputer environment. The solution consists of a domain-specific visual language for composing complex services from simple services called Multimedia Stream...
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A Regular Expression Matching Application with Configurable Data Intensity for Testing Heterogeneous HPC Systems
PublikacjaModern High Performance Computing (HPC) systems are becoming increasingly heterogeneous in terms of utilized hardware, as well as software solutions. The problems, that we wish to efficiently solve using those systems have different complexity, not only considering magnitude, but also the type of complexity: computation, data or communication intensity. Developing new mechanisms for dealing with those complexities or choosing an...
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A Workflow Application for Parallel Processing of Big Data from an Internet Portal
PublikacjaThe paper presents a workflow application for efficient parallel processing of data downloaded from an Internet portal. The workflow partitions input files into subdirectories which are further split for parallel processing by services installed on distinct computer nodes. This way, analysis of the first ready subdirectories can start fast and is handled by services implemented as parallel multithreaded applications using multiple...
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Accelerating Video Frames Classification With Metric Based Scene Segmentation
PublikacjaThis paper addresses the problem of the efficient classification of images in a video stream in cases, where all of the video has to be labeled. Realizing the similarity of consecutive frames, we introduce a set of simple metrics to measure that similarity. To use these observations for decreasing the number of necessary classifications, we propose a scene segmentation algorithm. Performed experiments have evaluated the acquired...
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Accelerometer-based Human Activity Recognition and the Impact of the Sample Size
PublikacjaThe presented study focused on the recognition of eight user activities (e.g. walking, lying, climbing stairs) basing on the measurements from an accelerometer embedded in a mobile device. It is assumed that the device is carried in a specific location of the user’s clothing. Three types of classifiers were tested on different sizes of the samples. The influence of the time window (the duration of a single trial) on selected activities...
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AN ALGORITHM FOR PORTAL HYPERTENSIVE GASTROPATHY RECOGNITION ON THE ENDOSCOPIC RECORDINGS
PublikacjaSymptoms recognition of portal hypertensive gastropathy (PHG) can be done by analysing endoscopic recordings, but manual analysis done by physician may take a long time. This increases probability of missing some symptoms and automated methods may be applied to prevent that. In this paper a novel hybrid algorithm for recognition of early stage of portal hypertensive gastropathy is proposed. First image preprocessing is described....
Rok 2009
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A JEE-based modelling and execution environment for workflow applications with just-in-time service selection
PublikacjaArtykuł prezentuje model scenariusza z dynamicznym wyborem usług do wykonania zadań scenariusza. Adekwatność rozwiązania została zaprezentowana dla zastosowań naukowych i biznesowych w warunkach kiedy dostępność usług się zmienia i usługi powinny być wybierane w trakcie działania scenariusza a nie przed jego rozpoczęciem. Pokazano, że dla scenariusza naukowego z powtarzalnymi symulacjami, algorytm dobiera usługi, aby zminimalizować...
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A video monitoring system using ontology-driven identification of threats
PublikacjaIn this paper, we present a video monitoring systemthat leverages image recognition and ontological reasoningabout threats. In the solution, an image processing subsystemuses video recording of a monitored area and recognizesknown concepts in scenes. Then, a reasoning subsystem uses anontological description of security conditions and informationfrom image recognition to check if a violation of a conditionhas occurred. If a threat...
Rok 2015
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A method for counting people attending large public events
PublikacjaThe algorithm for people counting in crowded scenes, based on the idea of virtual gate which uses optical flow method is presented. The concept and practical application of the developed algorithm under real conditions is depicted. The aim of the work is to estimate the number of people passing through entrances of a large sport hall. The most challenging problem was the unpredicted behavior of people while entering the building....
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Adaption of Open Science Paradigm at Gdańsk University of Technology
PublikacjaOpen Access plays growing role in sharing results of today's research. The movement is very strong and many Universities, including Gdańsk University of Technology, are adapting this approach. This paper presents general information about Open Access movement and the approach adapted by the Gdańsk University of Technology. The components of Open Science platform as well as the procedures are described.
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Analiza kreatywności oraz wpływu elementów typowo marketingowych wykorzystywanych na internetowych portalach branży turystycznej
PublikacjaW obecnej chwili konkurencja pomiędzy agencjami turystycznymi operującymi na globalnym rynku w Internecie, w powiązaniu ze stale rosnącą biznesową dojrzałością całego sektora, wymusiła wprowadzanie kreatywnych oraz celowo zorientowanych elementów o naturze typowo marketingowej w celu wywołania wrażenia unikalności w sposobie traktowania klienta. Marketingowe elementy o charakterze klasycznym, np. zniżki typu „first minute”, „last...
Rok 2008
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A model of an Ontology Oriented Threat Detection System (OOTDS)
PublikacjaArtykuł omawia projekt zorientowanego na ontologię systemu wykrywania zagrożeń (OOTDS) dla środowiska opisywalnego przez ontologię Bayesowską pierwszego rzędu wyrażoną w języku PR-OWL. Zakłada się, że środowisko monitorowane jest przez zbiór czujników dostarczających nieustannie systemowi OOTDS zdarzenia odzwierciedlające zmiany środowiska, wyrażone w specyficzny dla czujników sposób. Dedykowane moduły obsługi zdarzeń konwertują...
Rok 2018
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A Solution to Image Processing with Parallel MPI I/O and Distributed NVRAM Cache
PublikacjaThe paper presents a new approach to parallel image processing using byte addressable, non-volatile memory (NVRAM). We show that our custom built MPI I/O implementation of selected functions that use a distributed cache that incorporates NVRAMs located in cluster nodes can be used for efficient processing of large images. We demonstrate performance benefits of such a solution compared to a traditional implementation without NVRAM...
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Adopting Collaborative Games into Agile Software Development
PublikacjaAlthough the emergence of agile methods has triggered a growing awareness that social factors have a crucial impact on the success of software projects, neither the Scrum Guide nor the Agile Manifesto prescribe techniques that aid the human side of software development. To address this challenge, we enriched the Scrum process with a set of collaborative games. Collaborative games refer to techniques inspired by game play, but designed...
Rok 2020
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Abdominal Aortic Aneurysm segmentation from contrast-enhanced computed tomography angiography using deep convolutional networks
PublikacjaOne of the most common imaging methods for diagnosing an abdominal aortic aneurysm, and an endoleak detection is computed tomography angiography. In this paper, we address the problem of aorta and thrombus semantic segmentation, what is a mandatory step to estimate aortic aneurysm diameter. Three end-to-end convolutional neural networks were trained and evaluated. Finally, we proposed an ensemble of deep neural networks with underlying...
Rok 2022
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Active Learning Based on Crowdsourced Data
PublikacjaThe paper proposes a crowdsourcing-based approach for annotated data acquisition and means to support Active Learning training approach. In the proposed solution, aimed at data engineers, the knowledge of the crowd serves as an oracle that is able to judge whether the given sample is informative or not. The proposed solution reduces the amount of work needed to annotate large sets of data. Furthermore, it allows a perpetual increase...
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Algorytm mrówkowy do zarządzania zasobami sprzętowymi chmury obliczeniowej w przypadku różnych kategorii usług
PublikacjaZarządzanie chmurą obliczeniową odbywa się na dwóch poziomach: zarządzanie żądaniami klientów chmury oraz zarządzanie jej infrastrukturą, na której te usługi są realizowane. Analizując standardy dotyczące zarządzania usługami, w niniejszym rozdziale skoncentrowano się na drugim poziomie zarządzania, którego głównym celem jest efektywne wykonanie wskazanej usługi (lub usług) na dostępnych zasobach sprzętowych, tak by spełnione zostały...
Rok 2006
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Administrowanie systemami internetowymi
PublikacjaPrzedstawiono problematykę administrowania systemami internetowymi. Omówiono zasady konfguracji połączeń, integracji oraz konfguracji serwisów internetowych. Ponadto praca przedstawia zasady uwierzy-telniania użytkowników w rozproszonym systemach z wykorzystaniem mechanizmów usług katalogowych takich jak LDAP. Uwzględniono również problematykę bezpieczeństwa systemów internetowych ze szczególnym zwróceniem uwagi na najczęstsze...
Rok 2019
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Advances in Architectures, Big Data, and Machine Learning Techniques for Complex Internet of Things Systems
PublikacjaTe feld of Big Data is rapidly developing with a lot of ongoing research, which will likely continue to expand in the future. A crucial part of this is Knowledge Discovery from Data (KDD), also known as the Knowledge Discovery Process (KDP). Tis process is a very complex procedure, and for that reason it is essential to divide it into several steps (Figure 1). Some authors use fve steps to describe this procedure, whereas others...
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An Analysis of Neural Word Representations for Wikipedia Articles Classification
PublikacjaOne of the current popular methods of generating word representations is an approach based on the analysis of large document collections with neural networks. It creates so-called word-embeddings that attempt to learn relationships between words and encode this information in the form of a low-dimensional vector. The goal of this paper is to examine the differences between the most popular embedding models and the typical bag-of-words...
Rok 2024
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An intelligent cellular automaton scheme for modelling forest fires
PublikacjaForest fires have devastating consequences for the environment, the economy and human lives. Understanding their dynamics is therefore crucial for planning the resources allocated to combat them effectively. In a world where the incidence of such phenomena is increasing every year, the demand for efficient and accurate computational models is becoming increasingly necessary. In this study, we perform a revision of an initial proposal...
Rok 2010
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Analiza bezpieczeństwa scenariuszy usług
PublikacjaPrzedstawiono krótki opis architektury przetwarzania skierowanego na usługi. Omówiono problemy zabezpieczania na poziomie komunikujących sie komputerów, wymiany komunikatów SOAP oraz realizacji złożonych, interaktywnych scenariuszy Web Services. Porównano standardy bezpieczeństwa dotyczące Web Services.
Rok 2007
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Analiza wpływu pozatechnicznych elementów witryn internetowych na klienta w segmencie rynkowym B2C
PublikacjaPrzedstawiono marketingową problematykę handlu internetowego w zorientowaniu na klienta detalicznego. Zaprezentowano szereg pozatechnicznych elementów mających wpływ na postrzeganie witryny przez odwiedzającego ją Internautę. Dokonano przeglądu technik wpływania na zachowanie ludzi oraz przeanalizowano możliwości ich wykorzystania na komercyjnych stronach www. Wyciągnięto wnioski natury ogólnej mogące służyć projektantom stron...