Detection of code smells using machine learning techniques combined with data-balancing methods

Code smells are prevalent issues in software design that arise when implementation or design principles are violated. These issues manifest as symptoms or anomalies in the source code. Timely identification of code smells plays a crucial role in enhancing software quality and facilitating software maintenance. Previous studies have shown that code smell detection can be accomplished through the utilization of machine learning (ML) methods. However, despite their increasing popularity, research suggests that the suitability of these methods are not always appropriate due to the problem of imbalanced data. Consequently, the effectiveness of ML models may be negatively affected. This study aims to propose a novel method for detecting code smells by employing five ML algorithms, namely decision tree (DT), k-nearest neighbors (K-NN), support vector machine (SVM), XGboost (XGB), and multi-layer perceptron (MLP). Additionally, to tackle the challenge of imbalanced data, the proposed method incorporates the random oversampling technique. Experiments were conducted in this study using four datasets that encompassed code smells, specifically god-class, data-class, long-method, and feature-envy. The experimental outcomes were evaluated and compared using various performance metrics. Upon comparing the outcomes of our models on both the balanced and original datasets, we found that the XGB model achieved the highest accuracy of 100% for detecting the data class and long method on the original datasets. In contrast, the highest accuracy of 100% was obtained for the data class and long method using DT, SVM, and XGB models on the balanced datasets. According to the empirical findings, there is significant promise in using ML techniques for the accurate prediction of code smells

Some aspects of grading Java code submissions in MOOCs

Recently, massive open online courses (MOOCs) have been offering a new online approach in the field of distance learning and online education. A typical MOOC course consists of video lectures, reading material and easily accessible tests for students. For a computer programming course, it is important to provide interactive, dynamic, online coding exercises and more complex programming assignments for learners. It is expedient for the students to receive prompt feedback on their coding submissions. Although MOOC automated programme evaluation subsystem is capable of assessing source programme files that are in learning management systems, in MOOC systems there is a grader that is responsible for evaluating students’ assignments with the result that course staff would be required to assess thousands of programmes submitted by the participants of the course without the benefit of an automatic grader. This paper presents a new concept for grading programming submissions of students and improved techniques based on the Java unit testing framework that enables automatic grading of code chunks. Some examples are also given such as the creation of unique exercises by dynamically generating the parameters of the assignment in a MOOC programming course combined with the kind of coding style recognition to teach coding standards

Tools, processes and factors influencing of code review

Code review is the most effective quality assurance strategy in software development where reviewers aim to identify defects and improve the quality of source code of both commercial and open-source software. Ultimately, the main purpose of code review activities is to produce better software products. Review comments are the building blocks of code review. There are many approaches to conduct reviews and analysis source code such as pair programming, informal inspections, and formal inspections. Reviewers are responsible for providing comments and suggestions to improve the quality of the proposed source code modifications. This work aims to succinctly describe code review process, giving a framework of the tools and factors influencing code review to aid reviewers and authors in the code review stages and choose the suitable code review tool

Csoporttechnológia-alapú tervezés és ütemezés támogatása diszkrét matematikai modellekkel és módszerekkel = Supporting of the Group Technology Based Design, Planning and Scheduling by Means of Discrete Mathematical Models and Methods

A kutatási témában - a kitűzött célokkal összhangban - négy területen értünk el eredményeket. A választási feladatok területén a csoporttechnológia-alapú gyártócellák kialakításához egy új matematikai módszert dolgoztunk ki, amely a fogalomhálók dinamikusan fejlődő új területéhez kapcsolódik. Az eljáráshoz szoftver is készült, amelyet irodalmi összehasonlítás alapján sikeresen teszteltünk. A termelési, illetve gyártási feladatok csoportos ütemezéséhez kapcsolódóan főként a rugalmas és igény szerinti tömeggyártás igényeit is támogatni képes, kiterjesztett ütemezési modell és szoftver kifejlesztésére törekedtünk. A munkadarabok csoportjainak diszkrét ismérvek alapján való kialakítása terén elért új eredmények a fogalomhálók elméletének továbbfejlesztését jelentik a kutatócsoport által bevezetett ún. dobozhálók tulajdonságainak és alkalmazási lehetőségeinek feltárásával. Az intenzitás alapú optimalizálási feladatok csoporttechnológiai környezetben való kitűzése és megoldása szükségessé tette, hogy kidolgozzuk a diszkrét termelési folyamatok intenzitás-alapú modellezésének és optimalizálásának egységes elméleti alapjait az ún. termelési háromszög modell felhasználásával. Az elért eredmények teljes mértékben általánosíthatók csoporttechnológiai környezetre, mivel az átlagos intenzitás fogalma éppen a mindenkori csoport reprezentásához rendelhető hozzá a termelés ill. gyártás különböző hierarchiai szintjein. A kutatási témához két PhD értekezés és számos publikáció kapcsolódik. | In the research project, in accordance with the declared objectives, we obtained results in four fields. In the field of selection tasks we elaborated a new mathematical method suitable for creating Group Technology (GT) based manufacturing cells, which is connected with the new area of concept lattices developing dynamically. A software is also elaborated and successfully tested on the basis of literature. In connection with the grouped production tasks we concentrated our efforts to develop an extended scheduling model and software capable for supporting the demands of flexible and customized mass production. In the area of creating workpiece groups on the basis of discrete attributes we obtained new results by means of revealing the properties and application possibilities of so-called "box-lattices". It means further developing the theory of concept lattices. In order to define and solve intensity (rate) based optimization tasks in GT environment, we elaborated the unified theoretical basics of intensity based discrete production processes by using the so-called "production triangle model". The results obtained so far can be generalized to GT environment in full, because the concept of average intensity can be allocated to the representative member of the given group at the different hierarchy levels of production and manufacturing, respectively. Two PhD Theses before defending procedure directly and numerous publications are connected with the project

Molecular Dynamics and Metadynamics Insights of 1,4-Dioxane-Induced Structural Changes of Biomembrane Models

1,4-dioxane is a cytotoxic B2 type human carcinogen, a serious water pollutant produced solely by industrial activity. The effect of 1,4-dioxane on phospholipid membrane models composed by DPPC and its branched isomer (IPPC) was investigated using MD simulations. Clear and polluted membranes were compared by membrane parameters such as APL, VPL, compressibility modulus, membrane thickness and orderliness of lipid tails. While neat systems significantly differ from each other, the presence of the pollutant has the same effect on both types of lipid membranes: high density of dioxane appears at the vicinity of ester groups which pushes away lipid headgroups from each other, leading to an overall change in lipid structure: APL and VPL grows, while the orderliness of lipid tails, membrane thickness and compressibility modulus decreases. Orientational preferences of water and dioxane molecules were also investigated and different membrane regions have been specified according to the stance of water molecules. Free energy profile for 1,4-dioxane penetration mechanism into DPPC membranes was carried out using metadynamics for two different concentrations of the pollutant (c1=7.51 g/dm3 , c2=75.10 g/dm3 ), which showed that the higher the concentration is, the lower the free energy of penetration gets. Only a small free energy barrier was found in the headgroup region and accumulation of dioxane is thermodynamically unfavored in the middle of the bilayer. The penetration mechanism has been described in detail based on the orientational preference of 1,4-dioxane molecules and the free energy profiles

An Ab Initio Investigation of the 4,4′-Methlylene Diphenyl Diamine (4,4′-MDA) Formation from the Reaction of Aniline with Formaldehyde

The most commonly applied industrial synthesis of 4,4′-methylene diphenyl diamine (4,4′-MDA), an important polyurethane intermediate, is the reaction of aniline and formaldehyde. Molecular understanding of the 4,4′-MDA formation can provide strategy to prevent from side reactions. In this work, a molecular mechanism consisted of eight consecutive, elementary reaction steps from anilines and formaldehyde to the formation of 4,4′-MDA in acidic media is proposed using accurate G3MP2B3 composite quantum chemical method. Then G3MP2B3-SMD results in aqueous and aniline solutions were compared to the gas phase mechanism. Based on the gas phase calculations standard enthalpy of formation, entropy and heat capacity values were evaluated using G3MP2B3 results for intermediates The proposed mechanism was critically evaluated and important side reactions are considered: the competition of formation of protonated p-aminobenzylaniline (PABAH+), protonated aminal (AMH+) and o-aminobenzylaniline (OABAH+). Competing reactions of the 4,4′-MDA formation is also thermodynamically analyzed such as the formation of 2,4-MDAH+, 3,4-MDAH+. AMH+ can be formed through loose transition state, but it becomes kinetic dead-end, while formation of significant amount of 2,4-MDA is plausible through low-lying transition state. The acid strength of the key intermediates such as N-methylenebenzeneanilium, PABAH+, 4-methylidenecyclohexa-2,5-diene-1-iminium, and AMH+ was estimated by relative pKa calculation

Termelőszövetkezeti jogviták

INST: L_08