Artykuły (CN-csci)

Permanent URI for this collectionhttps://repo.agh.edu.pl/handle/AGH/102784

Artykuły czasopisma Computer Science

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Access status: Open Access ,
Acceptance testing of web applications with Test Description Language
(Wydawnictwa AGH, 2014) Olek, Łukasz; Alchimowicz, Bartosz; Nawrocki, Jerzy Ryszard
Acceptance tests are usually created by a client after a part of a system is implemented. However, some methodologies propose the elaboration of test cases before implementing a system. This approach increases the probability of system implementation that fulfills requirements, but may be problematic for customers and testers. To allow acceptance testing in such conditions, we propose to define test cases by recording them on an interactive mockup (a low detailed user-interface prototype). The paper focuses on Test Description Language, a notation used to store test cases.
Access status: Open Access ,
High Energy Physics experiments in grid computing networks
(Wydawnictwa AGH, 2008) Olszewski, Andrzej
The demand for computing resources used for detector simulations and data analysis in High Energy Physics (HEP) experiments is constantly increasing due to the development of studies of rare physics processes in partide interactions. The latest generation of experiments at the newly built LHC accelerator at CERN in Geneva is planning to use computing networks for their data processing needs. A Worldwide LHC Computing Grid (WLCG) organization has been created to develop a Grid with properties matching the needs of these experiments. In this paper we present the use of Grid computing by HEP experiments and describe activities at the participating computing centers with the case of Academic Computing Center, ACK Cyfronet AGH, Kraków, Poland.
Access status: Open Access ,
Automatic indexation of cultural heritage 3D object
(Wydawnictwa AGH, 2025) Le-Tien, Mau; Nguyen-Tan, Khoi; Raffin, Romain
There has been significant evolution in the fields of 3D digitization thanks to the development of 3D reconstruction and geometry processing. The results of digitization researches have been widely applied in many fields, especially in Cultural Heritage and Archaeology. Reconstruction, characterization and annotation of components forming 3D objects have become an effective tool for research, conservation and promotion of archaeological relics. The aim of this paper is to propose a process of 3D model reconstruction, segmentation and annotation on the basis of a enhanced corresponding 2D dataset. A machine learning method is used for the semantic segmentation of 2D images, thereby label, annotate and reconstruct a 3D model based upon links between distinctive invariant features, orientation of images, and depth map of images. The initial result as a data basis for research, reconstruction and identification of parts in 3D objects is applied in the reconstruction of archaeological relics, object identification, 3D printing, etc. Our work uses the data collected from the Museum of Cham Sculpture DaNang and the Myson QuangNam sanctuary in VietNam, to carry out the proposed method.
Access status: Open Access ,
An efficient approach for view selection for data warehouse using tree mining and evolutionary computation
(Wydawnictwa AGH, 2018) Thakare, Atul; Deshpande, Parag
The selection of a proper set of views to materialize plays an important role in database performance. There are many methods of view selection that use different techniques and frameworks to select an efficient set of views for materialization. In this paper, we present a new efficient scalable method for view selection under the given storage constraints using a tree mining approach and evolutionary optimization. The tree mining algorithm is designed to determine the exact frequency of (sub)queries in the historical SQL dataset. The Query Cost model achieves the objective of maximizing the performance benefits from the final view set that is derived from the frequent view set given by the tree mining algorithm. The performance benefit of a query is defined as a function of query frequency, query creation cost, and query maintenance cost. The experimental results show that the proposed method is successful in recommending a solution that is fairly close to an optimal solution.
Access status: Open Access ,
Turing machine approach to runtime software adaptation
(Wydawnictwa AGH, 2014) Rudy, Jarosław
In this paper, the problem of applying changes to software at runtime is considered. The computability theory is used in order to develop a more general and programming-language-independent model of computation with support for runtime changes. Various types of runtime changes were defined in terms of computable functions and Turing machines. The properties of such functions and machines were used to prove that arbitrary runtime changes on Turing machines are impossible in general cases. A method of Turing machine decomposition into subtasks was presented and runtime changes were defined through transformations of the subtask graph. Requirements for the possible changes were considered with regard to the possibility of subtask execution during such changes. Finally, a runtime change model of computation was defined by extension of the Universal Turing Machine.
Access status: Open Access ,
CV19T, a novel bio-socially inspired method, belonging to a new nature-inspired metaheuristics class
(Wydawnictwa AGH, 2024) Bouthina, Saib; Abdessemed, Mohamed-Rida; Hocine, Riadh
The paper presents CV19T, a novel bio-socially inspired meta-heuristic, where the cornerstone on which rests is the relationship between humans crowding density, on one side, influenced by their mobility, mutual attractiveness to each other and individual consciousness, and on the other side, the amazing speed of COVID-19 propagation. CV19T originality resides in the fact of combining features from two completely distinct and famous classes, namely: swarm intelligence and Evolutionary Algorithms. Moreover, CV19T extends elitism concept (i.e. survival of the most powerful), on which are based courant evolutionist approaches to the survival of the most beneficial one. Also, CV19T shows that additional parameters can increase control of its behaviour, in many cases, leading to rise in its results relevance. To validate CV19T, it was tested on benchmarks set, including 23 functions (unimodal, multimodal and fixeddimensional multimodal) and 4 real-world problems.
Access status: Open Access ,
Optimized jk-nearest neighbor based online signature verification and evaluation of main parameters
(Wydawnictwa AGH, 2021) Saleem, Muhammad; Kovari, Bence
In this paper, we propose an enhanced $jk$-nearest neighbor ($jk$-NN) algorithm for online signature verification. The effect of its main parameters is evaluated and used to build an optimized system. The results show that the $jk$-NN classifier improves the verification accuracy by 0.73–10% as compared to a traditional one-class $k$-NN classifier. The algorithm achieved reasonable accuracy for different databases: a 3.93% average error rate when using the SVC2004, 2.6% for the MCYT-100, 1.75% for the SigComp'11, and 6% for the SigComp'15 databases. These results followed a state-of-the-art accuracy evaluation where both forged and genuine signatures were used in the training phase. Another scenario is also presented in this paper by using an optimized $jk$-NN algorithm that uses specifically chosen parameters and a procedure to pick the optimal value for $k$ using only the signer’s reference signatures to build a practical verification system for real-life scenarios where only these signatures are available. By applying the proposed algorithm, the average error rates that were achieved were 8% for SVC2004, 3.26% for MCYT-100, 13% for SigComp'15, and 2.22% for SigComp'11.
Access status: Open Access ,
Simple cyclic movements as a distinct autism feature – computational approach
(Wydawnictwa AGH, 2013) Dobosz, Krzysztof; Mikołajewski, Dariusz; Wójcik, Grzegorz Marcin; Duch, Włodzisław
A diversity of symptoms in autism dictates a broad definition of AutismSpec-trum of Disorders (ASD). Each year, the percentage of children diagnosed with ASD is growing. One common diagnostic feature in individuals with ASD is the tendency to exhibit atypical simple cyclic movements.The motor brain activity seems to generate a periodic attractor state that is hard to escape. Despite numerous studies, scientists and clinicians do not know exactly if ASD is a result of a simple yet general mechanism or of a complex set of mechanisms (either on the neural, molecular and system levels). Simulations using the biologically- relevant neural network model presented here may help to reveal the simplest mechanisms that may be responsible for specific behavior. Abnormal neural fatigue mechanisms may be responsible for motor symptoms as well as many (or perhaps all) of the other symptoms observed in ASD.
Access status: Open Access ,
COMPACT: biometric dataset of face images acquired in uncontrolled indoor environment
(Wydawnictwa AGH, 2019) Włodarczyk, Michał; Kacperski, Damian; Sankowski, Wojciech; Grabowski, Kamil
Biometric databases are important components that help improve the performanceof state-of-the-art recognition applications. The availability of more andmore challenging data is attracting the attention of researchers, who are systematicallydeveloping novel recognition algorithms and increasing the accuracyof identification. Surprisingly, most of the popular face datasets (like LFW orIJBA) are not fully unconstrained. The majority of the available images werenot acquired on-the-move, which reduces the amount of blurring that is causedby motion or incorrect focusing. Therefore, the COMPACT database for studyingless-cooperative face recognition is introduced in this paper. The datasetconsists of high-resolution images of 108 subjects acquired in a fully automatedmanner as people go through the recognition gate. This ensures that the collecteddata contains real-world degradation factors: different distances, expressions,occlusions, pose variations, and motion blur. Additionally, the authorsconducted a series of experiments that verified the face-recognition performanceon the collected data.
Access status: Open Access ,
Multifunctional unit for reverse conversion and sign detection based on five-moduli set {2 2n, 2n + 1, 2n − 1, 2n + 3, 2n − 3}
(Wydawnictwa AGH, 2021) Mojahed, Mohsen; Molahosseini, Amir Sabbagh; Zarandi, Azadeh Alsadat Emrani
A high dynamic range moduli set $\{2^{2n}, 2^{n}+1, 2^{n}-1, 2^{n}+3, 2^{n}-3\}$ has recently been introduced as an arithmetically balanced five-modull set for the residue number system (RNS). In order to utilize this moduli set in applications handling signed numbers, two important components are needed: a sign detector, and a signed reverse converter. However, having both of these components results in high-hardware requirements, which makes RNS impractical. This paper overcomes this problem by designing a unified unit that can perform both signed reverse conversion as well as sign detection through the reuse of hardware. To the authors’ knowledge, this is the first attempt to design a sign detector for a moduli set that includes a $\{2^{n}3\}$ moduli. In order to achieve a hardwareamenable design, we first improved the performance of the previous unsigned reverse converter for this moduli set. Then, we extracted a sign-detection method from the structure of the reverse converter. Finally, we made an unsigned reverse converter-to-sign converter through the use of the extracted sign signal from the reverse converter. The experimental results show that the proposed reverse convertor and sign detector result in improvements of 31% and 28% in area and delay, respectively, as compared to the previous unsigned reverse convertor with sign output using a comparator.
Access status: Open Access ,
Identifying limits of scalability in distributed, heterogeneous, layer based monitoring concepts like SLAte
(Wydawnictwa AGH, 2012) Hilbrich, Marcus; Müller-Pfefferkorn, Ralph
In this paper we present the concept of a scalable job centric monitoring infrastructure. The overall performance of this distributed, layer based architecture called SLAte can be increased by installing additional servers to adapt to the demands of the monitored resources and users. Another important aspect is to offer a uniform global view on all data which are stored distributed to provide an easy access for users or visualisation tools. Additionally we discuss the impact of these uniform access layer on scalability.
Access status: Open Access ,
Extraction of scores and average from Algerian high-school degree transcripts
(Wydawnictwa AGH, 2020) Kefali, Abderrahmane; Drabsia, Soumia; Sari, Toufik; Chaoui, Mohammed; Ferkous, Chokri
A system for extracting scores and the average from Algerian high school degree transcripts is proposed. The system extracts the scores and average based on the localization of tables gathering this information, it consists of several stages. After preprocessing, the system locates the tables using ruling-line information as well as other text information. Therefore, the adopted localization approach can work even in the absence of certain ruling lines or the erasure and discontinuity of the lines. After this, the localized tables are segmented into columns and the columns into information cells. Finally, cell labeling is done based on prior knowledge of the table structure, allowing us to identify the scores and the average. Experiments have been conducted on a local dataset in order to evaluate the performances of our system and compare it to three public systems at three levels, the obtained results show the effectiveness of our system.
Access status: Open Access ,
Lower Precision calculation for option pricing
(Wydawnictwa AGH, 2017) Ścibisz-Mordelska, Katarzyna; Nielek, Radosław
The problem of options pricing is one of the most critical issues and fundamental building blocks in mathematical finance. The research includes deployment of lower precision type in two options pricing algorithms: Black-Scholes and Monte Carlo simulation. We make an assumption that the shorter the number used for calculations is (in bits), the more operations we are able to perform in the same time. The results are examined by a comparison to the outputs of single and double precision types. The major goal of the study is to indicate whether the lower precision types can be used in financial mathematics. The findings indicate that Black-Scholes provided more precise outputs than the basic implementation of Monte Carlo simulation. Modification of the Monte Carlo algorithm is also proposed. The research shows the limitations and opportunities of the lower precision type usage. In order to benefit from the application in terms of the time of calculation improved algorithms can be implemented on GPU or FPGA. We conclude that under particular restrictions the lower precision calculation can be used in mathematical finance.
Access status: Open Access ,
Time extensions of Petri nets for modelling and verification of hard real-time systems
(Wydawnictwa AGH, 2002) Samolej, Sławomir; Szmuc, Tomasz Bartłomiej
The main aim of the paper is a presentation of time extensions of Petri nets appropriate for modelling and analysis of hard real-time systems. It is assumed, that the extensions must provide a model of time flow, an ability to force a transition to fire within a stated timing constraint (the so-called the strong firing rule), and timing constraints represented by intervaIs. The presented survey includes extensions of classical Place/Transition Petri nets, as welI as the ones applied to high-level Petri nets. An expressiveness of each time extension is illustrated using simple hard real-time system. The paper includes also a brief description of analysis and verification methods related to the extensions, and a survey of software tooIs supporting modelling and analysis of the considered Petri nets.
Access status: Open Access ,
Compression of image sequences in interactive medical teleconsultations
(Wydawnictwa AGH, 2017) Malawski, Filip; Czekierda, Łukasz
Interactive medical teleconsultations are an important tool in modern medical practice. Their applications include remote diagnostics, conferences, workshops, and classes for students. In many cases, standard medium or low-end machines are employed, and the teleconsultation systems must be able to provide a high quality of user experience with very limited resources. Particularly problematic are large datasets consisting of image sequences that need to be accessed fluently. The main issue is insufficient internal memory, therefore, proper compression methods are crucial. However, a scenario where image sequences are kept in a compressed format in the internal memory and decompressed onthe-fly when displayed is difficult to implement due to performance issues. In this paper, we present methods for both lossy and lossless compression of medical image sequences that only require compatibility with the Pixel Shader 2.0 standard, which is present even on relatively old, low-end devices. Based on the evaluation of quality, size reduction, and performance, these methods have been proven to be suitable and beneficial for medical teleconsultation applications.
Access status: Open Access ,
Semigroups, groups and grammar inference problem
(Wydawnictwa AGH, 2002) Sokolicki, Zbigniew
In the paper we analyse a problem of inferring a grammar from a given sample of a language. We try to present an algebraic formalism capable of describing the issue. We consider two cases: a case of inferring canonical finite-state grammars, and a case of inferring general grammars. In both cases we define a semigroup structure. Finally we look at the possibility of getting a structure of a group.
Access status: Open Access ,
Machine learning models for predicting patients survival after liver transplantation
(Wydawnictwa AGH, 2018) Jarmulski, Wojciech; Wieczorkowska, Alicja; Trzaska, Mariusz; Ciszek, Michał; Paczek, Leszek
In our work, we have built models predicting whether a patient will lose an organ after a liver transplant within a specified time horizon. We have used the observations of bilirubin and creatinine in the whole first year after the transplantation to derive predictors, capturing not only their static value but also their variability. Our models indeed have a predictive power that proves the value of incorporating variability of biochemical measurements, and it is the first contribution of our paper. As the second contribution we have identified that full-complexity models such as random forests and gradient boosting lack sufficient interpretability despite having the best predictive power, which is important in medicine. We have found that generalized additive models (GAM) provide the desired interpretability, and their predictive power is closer to the predictions of full-complexity models than to the predictions of simple linear models.
Access status: Open Access ,
Investigation of aerodynamic parameters of solar plane airfoil using CFD modeling
(Wydawnictwa AGH, 2021) Jaszczur, Marek; Papis, Karolina; Książek, Michał; Czerwiński, Grzegorz; Wojtas, Gabriel; Koncewicz, Wojciech; Nabożna, Sylwia; Wójcik, Marcin
The technology of solar-powered aerial vehicles requires enormous financial support and further development. For this purpose, the computational fluid dynamic can be used. In order to carry out necessary analyses and model development in this research, ANSYS Fluent software was used. Using the first version of the AGH Solar Plane model, preliminary analysis of lift, drag and tearing off the stream was performed. Four new geometries were prepared on which the flattening of upper surfaces for fixing solar panels was tested. The results were validated in the aerodynamic tunnel using particle image velocimetry method. Taking into account all analyses, a number of recommendations have been prepared that will be implemented to create an aircraft, which meets all target requirements.
Access status: Open Access ,
Translation of use case scenarios to Java code
(Wydawnictwa AGH, 2012) Śmiałek, Michał; Jarzębowski, Norbert; Nowakowski, Wiktor
Use cases are usually treated as second class citizens in the software development chain based on models. Their textual descriptions (scenarios) are treated as informal input to more formal design models that can then be (semi-)automatically transformed down to code. In this paper we will show that use case scenarios can gain precise metamodel-based notation and semantics enabling automatic processing. What is more, we will show transformation algorithms that can transform use case scenarios directly to dynamic code in Java. The presented transformation can generate the full structure of the system following the MVP architectural pattern, including complete method contents for the application logic (Presenter) and presentation (View) layers. It also provides a code skeleton for the domain logic (Model) layer. The use case notation and the transformation were implemented within a sophisticated tool suite. Based on this, the paper discusses the evaluation efforts based on a case study.
Access status: Open Access ,
Population diversity in ant-inspired optimization algorithms
(Wydawnictwa AGH, 2021) Byrski, Aleksander; Węgrzyński, Krzysztof; Radwański, Wojciech; Starzec, Grażyna; Starzec, Mateusz; Bargiel, Monika; Urbańczyk, Aleksandra; Kisiel-Dorohinicki, Marek
Measuring the diversity in evolutionary algorithms that work in real-value search spaces is often computationally complex, but it is feasible, however, measuring the diversity in combinatorial domains is practically impossible. Nevertheless, in this paper we propose several practical and feasible diversitymeasurement techniques that are dedicated to ant colony optimization algorithms, leveraging the fact that we can focus on a pheromone table even though an analysis of the search space is at least an NP problem where the direct outcomes of the search are expressed and can be analyzed. Besides sketching out the algorithms, we apply them to several benchmark problems and discuss their efficacy.