Computer Science
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ISSN 1508-2806
e-ISSN: 2300-7036
Issue Date
2021
Volume
Vol. 22
Number
No. 1
Description
Reviewed by: Andrzej Opalinski, Komlen Lalovic, Szymon Szott, Artur Tyliszczak, Daniela Milosevic, Wojciech Turek, Piotr Dziurzanski, Oluwakemi Abikoye, Michal Wrzeszcz, Luca Passarella
Journal Volume
Projects
Pages
Articles
Complexfuzzy: novel clustering method for selecting training instances of cross-project defect prediction
(Wydawnictwa AGH, 2021) Oztürk, Muhammed Maruf
Over the last decade, researchers have investigated to what extent cross-project defect prediction (CPDP) shows advantages over traditional defect prediction settings. These works do not take the training and testing data of defect prediction from the same project, instead, dissimilar projects are employed. Selecting the proper training data plays an important role in terms of the success of CPDP. In this study, a novel clustering method called complexFuzzy is presented for selecting the training data of CPDP. The method reveals the most defective instances that the experimental predictors exploit in order to complete the training. To that end, a fuzzy-based membership is constructed on the data sets. Hence, overfitting (which is a crucial problem in CPDP training) is alleviated. The performance of complexFuzzy is compared to its 5 counterparts on 29 data sets by utilizing 4 classifiers. According to the obtained results, complexFuzzy is superior to other clustering methods in CPDP performance.
Hierarchical state machine model for analyzing safety hazards in real-time systems
(Wydawnictwa AGH, 2021) Bakr, Ahmed M.; Salama, May; Alsammak, Abdelwahab K.
Real-time systems must avoid hazardous situations. To achieve this, their functionality should be investigated under time constraints. A model based on Hierarchical Communicating Real-time State Machine (H-CRSM) and analysis methodology is proposed in this paper with the objective of obtaining any hazardous events that may occur in the input ANSI-C program. The system outputs a scenario list of the different hazards. A path in the code showing the cause of the undesirable event is associated with each hazardous scenario. The strength of the proposed methodology is that the process of hazardous situation detection does not require the running of the ANSI-C program many times with distinct values for the inputs. It also focuses on analyzing the software level of the life cycle. It is not like most of the verification and analysis tools that check system levels. The system level may be bug-free, but the software level may not be.
Circle formation by asynchronous opaque robots on infinite grid
(Wydawnictwa AGH, 2021) Adhikary, Ranendu; Kundu, Manash Kumar; Sau, Buddhadeb
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.
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.
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.