Technical University Of Cluj-Napoca Research Articles

Deep Learning in Endoscopic Ultrasound: A Breakthrough in Detecting Distal Cholangiocarcinoma

Introduction: Cholangiocarcinoma (CCA) is a highly lethal malignancy originating in the bile ducts, often diagnosed late with poor prognosis. Differentiating benign from malignant biliary tumors remains challenging, necessitating advanced diagnostic techniques. Objective: This study aims to enhance the diagnostic accuracy of endoscopic ultrasound (EUS) for distal cholangiocarcinoma (dCCA) using advanced convolutional neural networks (CCNs) for the classification and segmentation of EUS images, specifically targeting dCCAs, the pancreas, and the bile duct. Materials and Methods: In this retrospective study, EUS images from patients diagnosed with dCCA via biopsy and an EUS-identified bile duct tumor were evaluated. A custom CNN was developed for classification, trained on 156 EUS images. To enhance the model’s robustness, image augmentation techniques were applied, generating a total of 1248 images. For tumor and organ segmentation, the DeepLabv3+ network with ResNet50 architecture was utilized, employing Tversky loss to manage unbalanced classes. Performance evaluation included metrics such as accuracy, sensitivity, specificity, and Intersection over Union (IoU). These methods were implemented in collaboration with the ADAPTED Research Group at the Technical University of Cluj-Napoca. Results: The classification model achieved a high accuracy of 97.82%, with precision and specificity both at 100% and sensitivity at 94.44%. The segmentation models for the pancreas and bile duct demonstrated global accuracies of 84% and 90%, respectively, with robust IoU scores indicating good overlap between predicted and actual contours. The application performed better than the UNet model, particularly in generalization and boundary delineation. Conclusions: This study demonstrates the significant potential of AI in EUS imaging for dCCA, presenting a robust tool that enhances diagnostic accuracy and efficiency. The developed MATLAB application serves as a valuable aid for medical professionals, facilitating informed decision-making and improving patient outcomes in the diagnosis of cholangiocarcinoma and related pathologies.

Practical solutions for microgrid energy management: Integrating solar forecasting and correction algorithms

Nowadays, the shift towards renewable energies is happening at an exponential pace. Microgrids are an integral part in integrating renewable energies into the global energy mix. Due to the volatility of renewables, such as solar or wind, proper energy management is needed to avoid generation or load curtailment. This issue is addressed throughout the literature using a wide variety of strategies, ranging from classical linear to nature inspired metaheuristic optimization algorithms. This paper goes beyond the simulation phase of different optimization algorithms and addresses the optimal energy management problem by proposing a novel framework to integrate optimization strategies into the daily operation of microgrids. The proposed framework showcases 3 practical methods for controlling the distributed generators, as well as a communication scheme which facilitates the data transfer between the machine running the optimization strategy and the energy management system of the microgrid. The framework is demonstrated on a small-scale islanded microgrid setup, located at the Technical University of Cluj-Napoca. The microgrid setup consists of a photovoltaic array, a battery energy storage system and two dispatchable generators. A two-stage optimization strategy is used, consisting of a day-ahead stage, which uses the solar forecast provided by the Global Forecast System, prior to each day, to issue a working plan for the dispatchable generators, and an intra-day stage, which uses hourly solar forecasts, issued during the day, to adjust the operation of the microgrid and minimize the error between the day-ahead solar forecast and the actual weather conditions. Mixed integer linear programming is used to solve the optimization problem and validate the correct operation of the proposed framework over two case studies. The results show that the microgrid works as intended, in both scenarios, as well as the benefits of using an intra-day correction stage.

Life cycle assessment of LED luminaire and impact on lighting installation – A case study

In the presented study the Life Cycle Assessment of a LED suspended luminaire manufactured in Romania was performed, with the use of One Click LCA software. The results of the calculations show that the main environmental impact of the LED luminaire is generated by the operational energy use (96.046 % percent of the total global warming potential fossil kg CO2e). The environmental impact at the manufacturing stage is determined mainly by the aluminium, found in higher percentage in the LED luminaire body, fixing clips, LED module and LED driver. The analysis was extended for a lighting installation composed of the studied LED suspended luminaire. At first, using DIALux evo 11 software, the correct number and position of the LED luminaires was established, while respecting the EN 12464-1 standard regulations. Different cases were considered, taking into consideration the solution of implementing daylight system control in educational rooms of the Building Services Engineering Faculty, Technical University of Cluj-Napoca, with effect in reduction of the operational energy use. By implementing the daylight control for the considered educational rooms, the global warming potential fossil due to the operational energy use can be reduced up to approx. 10 %.

DIGITAL ENVIRONMENTALLY SPECIFIC NEEDS OF A SMALL OPEN PIT EXPLOITATION IN A PROTECTED AREA (PART II)

This paper is Part II of specific digital need of a small open pit exploitation. Using several intersections extracted from Copernicus of European Union's Copernicus Land Monitoring Service information, and also the provided GIS Protected Area shapes of the Romanian Ministry of Environment [1], an open pit/quarry project is analyzed concerning the Protected Area Measurements in order to minimize the environmental impact and the investments costs. An ArcGIS Pro License of the Technical University of Cluj Napoca, North University Center of Baia Mare owned in the Faculty of Engineering was used combined with the Commercial License of Rhinoceros 3D.

ONLINE LEARNING EXPERIENCES OF ENGINEERING STUDENTS IN THE POST-PANDEMIC PERSPECTIVE

The COVID-19 pandemic has created a crisis that has critically affected higher education institutions. With the sudden shift to emergency remote education during the pandemic, students’ online experiences have become a growing concern among teachers. This study aims to gain insights into students’ experiences of online activities in a hybrid learning approach. A total of 80 students enrolled in undergraduate programs at the Technical University of Cluj-Napoca, Romania, responded to an open-ended online questionnaire. This study used the content analysis to find out the positive and negative experiences in online learning, the preference for continuing instruction in a certain format and the reason for choice. The results showed that students' resources and skills played an important role in terms of positive or negative study experiences: cost and time effectiveness, easy access to many study materials and good distance learning skills helped to cope with this pandemic, while little or no interaction with colleagues and teachers and too many hours on screen caused difficulties and dissatisfaction among other students. Despite these issues, most students are interested in continuing their online instruction, but also face-to-face or hybrid activities. This study can provide recommendations derived from the interpretation of participant feedback for improvements in future online learning experience

INSIGHTS INTO THE ATTITUDE TOWARDS REMOTE EDUCATION OF UNDERGRADUATE ENGINEERING STUDENTS

The implementation of emergency remote education due to the COVID-19 pandemic may affect students’ online learning attitudes. Exploring these attitudes, as higher education adapts to uncertainty, has become more critical than ever. This study aims to obtain information about students' attitudes towards remote education by studying in a hybrid format in the first semester of the 2021-2022 academic year due to the COVID-19 pandemic. A non-experimental research design with quantitative research methods was used. A total of 135 students enrolled in undergraduate programs at the Technical University of Cluj-Napoca, Romania, responded to the survey. The study found that students had a neutral attitude towards remote education. There was no statistically significant difference by gender and residence area. However, the results indicated that the 4th year students had higher attitude scores towards remote education than those in previous years. The findings of this study may also provide suggestions for further developments and improvements in students’ online learning attitudes and in the pedagogy of engineering disciplines in the post-pandemic perspective.

COVID-19 Pandemic: Impediment or Opportunity? Considerations Regarding the Physical-Health Impact and Well-Being among Romanian University Students

The global COVID-19 pandemic that is ongoing because of the Coronavirus II (SARS-CoV-2) has had until now a great impact on physical education and sports, especially due to the closure of training facilities and people’s lack of motivation. In Romania, physical activity (PA) and physical education (PE) have also been highly affected, especially among university students. To our knowledge, this is the first study conducted in Romania regarding the influence of the lockdown on the physical health and well-being of university students. This study aims to determine if and how the pandemic affected the university students’ mental and physical health in Romania, but also to highlight new strategies and approaches suggested by them through a questionnaire to enhance and motivate their participation in physical activities. Based on a cross-sectional design, a survey designed in two languages—Romanian and English—was completed by the students from the Technical University of Cluj-Napoca and foreign students that were on a mobility study visit through the Erasmus+ program in Romania. The questionnaire was filled out by 836 university students (age = 18–24 years; males: 57.73%). The findings showed that quarantine in Romania led to a significant increase in sedentarism among students and a reduction in energy for physical activity, which also affected their psychological well-being. The absence of social interactions and onsite classes led to a sedentary lifestyle among students and increased their fear and stress levels. The cancellation of all sports events and PA also led to fewer students remaining physically active. Time off training and leisure time activities caused by the ongoing restrictions might be used for new purposes, such as goal setting, overcoming injury, improving mobility, psychological development, and emphasizing strength sports for health. During the COVID-19 lockdown, sedentarism increased dramatically, especially among young people.

Preface

The ICEMS-BIOMED conference (https://icems-biomed.emcsb.ro/) was conceived as an biennial itinerant one, which - at the first edition, was organized by a consortium of three prestigious academic institutions from Romania, which share the same values, goals and scientific concerns: Technical University of Cluj-Napoca, “Nicolae Bălcescu” Land Forces Academy of Sibiu and “Ştefan cel Mare” University of Suceava.The first edition was hosted by the “Nicolae Bălcescu” Land Forces Academy of Sibiu, Romania, in May 2022, and the next editions will be organized in Cluj-Napoca, Romania, (2024) and Suceava, Romania (2026).List of Steering Committee, Conference Co-Chairs, Scientific and Reviewers Committee, Organizing Committee, Local Organizing Committee of “Nicolae Bălcescu” Land Forces Academy, Sibiu, Romania, Sponsors Acknowledgements, Editors of The Proceedings Volume are available in this pdf.

Study of Sports Motivation of Students from the Technical University of Cluj-Napoca

ABSTRACT. Introduction: The purpose of this article is to analyze the motivation to practice sports and physical activities among university students. Objectives: To identify the perceived reasons, as well as the existing differences between the students from the Technical University of Cluj-Napoca, regarding the motivation to practice sports and physical activities, depending on the gender and the area of residence. Methods: To find out what motivates university students to take part in various physical sports activities, we conducted a study in the academic year 2019-2020, with 257 participants. The method of quantitative research and the technique of administering questionnaires by sociological survey was used. The research tool was the Sports Motivation Scale-6 (SMS-6; Mallett et al., 2007), which is an evaluation of contextual motivation meant to ascertain the perceived reasons for practicing sports activities. Results: Regarding the behavior of practicing sports among students at the Technical University of Cluj-Napoca, male students are more motivated compared to female students and intrinsic motivation is predominant compared to other types of motivation. The area of residence does not seem to influence differently the motivation of students to practice sports, the scores obtained on each type of motivation being very close between the respondents from rural and urban areas. Conclusions: Physical education and sports are perceived by some students as a school obligation (external motivation), by others as a recreational, compensatory or recovery activity, while for most of them it means fun, a way to meet new people and to enjoy their company (intrinsic motivation).

Factors Influencing Students’ Behavior and Attitude towards Online Education during COVID-19

Universities around the world have faced a new pandemic, forcing the closure of campuses that are now conducting educational activities on online platforms. The paper presents a survey about students behavior and attitudes towards online education in the pandemic period from the Technical University of Cluj Napoca, Romania. A group of 300 students participated. The questionnaire was structured in four parts to determine student’s individual characteristics, student’s needs, students’ knowledge in using virtual platforms and students’ quality preferences for online education. The students said that online education in a pandemic situation is beneficial for 78% of them. A total of 41.7% percent of students appreciated the teachers’ teaching skills and the quality of online courses since the beginning of the pandemic, and 18.7% percent of the students appreciated the additional online materials for study to support their education. However, students found online education stressful, but preferred online assessment for evaluation. This pandemic has led to the new stage of Education 4.0, online education, and the need to harmonize methods of education with the requirements of new generations.

Study On Sports Socialization Among University Students

It is well known that participation in various physical sports activities contributes to the physical, psychological and emotional development of students, as well as their ability to socialize. A large part of students who come at university from other cities and have an increased need to socialize and build new groups of friends, especially in the first years of study, can use sports activities as a method of socialization. The purpose of this paper is to analyze how university students socialize through physical activities and sports. Using the method of quantitative research, the technique of administering questionnaires through sociological survey, we conducted a study with students from the Technical University of Cluj-Napoca, in the 2019-2020 academic year, with 594 of participants. The results of the study can help young people to use participation in various physical sports activities as an opportunity to socialize, meet other people and make new friends.

Preface

2021 International Conference on Cloud Computer, IoT and Intelligence System (CCIIS2021) is rescheduled to be held virtual via Tencent Meeting due to Covid-19. CCIIS2021 aims to provide a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of Cloud Computer, IoT and Intelligence System. Sincerely thanks for your paper submissions and support to CCIIS2021 conference.

Peer review declaration

All papers published in this volume of IOP Conference Series: Earth and Environmental Science have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.• Type of peer review: Double-blind• Conference submission management system: https://easychair.org/• Number of submissions received: 132• Number of submissions sent for review: 125• Number of submissions accepted: 116• Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 87.88%• Average number of reviews per paper: 2.21• Total number of reviewers involved: 86• Any additional info on review process: The review process was carried out by expert referees in their activity. All the papers were verified by a committee to be sure that they complied with the reviewers observations and if there were inconsistencies the papers were sent back to their authors. We can say that for some papers we needed three rounds of review for complying.• Contact person for queries: Name: Florin BODEAffiliation: Technical University of Cluj-Napoca, RomaniaEmail: florin.bode@termo.utcluj.ro

Designing of an original extruding system for 3D printing of parts made of plastic material in powder-state form

Since their advent, various 3D printing technologies have been developed, out of which the Fused Filament Fabrication, FFF has completely revolutionized the industry in the last years. Classical FFF printers are using a thermoplastic filament, which is heated to its melting point and then extruded layer by layer to materialize a three dimensional part. One of the most important subassemblies of the 3D printer which is the most representative is the extrusion sub-assembly system and the thermal demands to which is subjected. In this article, one original constructive variant of the extruding sub-assembly system has been conceived and thermal analyses of the variant was performed by using the finite element method so as to be used not only for printing parts made of plastic materials in filament form, but also plastic materials in the powder state form at the Technical University of Cluj-Napoca, Romania.

The Topological Optimization and the Design for Additive Manufacturing of a Steering Knuckle for Formula SAE Electric Vehicle

Formula Student represents the main motorsport activity for future professionals during their academic preparation. There is intensive migration from the prototypes with an internal combustion engine to electrical vehicles. The challenge of electric vehicles is the weight of the batteries which has to be compensated. The Topological Optimization process represents a method of removing volume and mass of the component (elements of mesh) with the aid of the discretization allowed by the finite element method (FEM) until a mass or stress constraint is attained. The results come in a complex shape, the material being kept only in the stressstrain directions. The manufacturing process is usually as complex, being employed high complexity technologies such as Selective Laser Melting (SLM). Improved strength-to-weight ratio materials are to be considered to obtain the most performant design of a specific component. The present paper presents the topological optimization process of the steering knuckle for the Formula Student electric vehicle of ART-TU Team of Technical University of Cluj-Napoca. It means that the part is simulated and optimized through Ansys Static Structural and there is done post-processing of the component along with Data Validation. The conclusions consist of the viability of the Topological Optimization process when designing complex components for performance automotive.

Modelling and evaluation of the Baseline Energy Consumption and the Key Performance Indicators in Technical University of Cluj‐Napoca buildings within a Demand Response programme: a case study

Demand response (DR) programmes offer to customers the opportunity to reduce the power peak and the energy consumption in response to a price signal or financial incentive. Typically, the request to reduce peak demands is made for a specific time period on a specific day, which is referred to as a DR event. To predict a reference energy consumption level in case of different buildings or blocks of buildings within the Technical University of Cluj-Napoca, this study proposes an artificial intelligence enhanced energy profiling method and a more intuitive yet simple method for baseline determination, easy to understand, which allows all the interested parties to estimate the energy and economy savings after a DR event. Once the baseline electric load profile is established, the aim of this study is to calculate some predefined key performance indicators. The two baseline detection methods are compared with each other as a measure of DR event effectiveness. The study has been conducted to clearly demonstrate the economic and environmental benefits of controlling the aggregated load curve in blocks of buildings within several effectively applied DR programmes.

Preface

The International Conference of the Carpathian Euro-Region Specialists in Industrial Systems (CEurSIS), 12th edition, is a conference held by the Faculty of Engineering, North University Center of Baia Mare, Technical University of Cluj Napoca, Romania. The objective is to ensure the conditions for high quality research and professional interactions in the benefit of science, technology and collaboration.The first edition of The International Meeting of the Carpathian Region Specialists, focused on Gears, was organized in 1996 under the coordination of Professor Eugen PAY Ph.D., Dr. H.C.. The following editions had a continuously grown multidisciplinary approach of the research and technological development activities, so the 2019 meeting comprises a wide spectrum of engineering. The scientific activities was completed with social and cultural activities.Until now more than 450 specialists from Romania, Poland, Hungary, Germany, Czech Republic, Austria, Serbia, Ukraine, Slovakia and Italy, with more than 570 papers, attended the CEurSIS Conference.We would like to thank everyone involved in organizing the conference and reviewing the papers presented.List of Editors are available in this pdf.

Sustainable Lighting-Retrofit Versus Dedicated Luminaires-Light Versus Power Quality

For the next few years millions of fluorescent luminaires will become waste and will be replaced by light-emitting diodes—LED luminaires. According to the Cost European Cooperation in Science & Technology Program, the next step will be shifting from sustainability to regeneration (enabling social and ecological systems to maintain a healthy state and to evolve); to reach this point, a is circular economy becomes necessary. The Technical University of Cluj-Napoca’s Lighting Engineering Laboratory—LEL—is the main lighting independent consultant in Transylvania (the north-west region of Romania). For the Building Services Faculty, LEL adopted different energy efficient lighting solutions to replace existing fluorescent T8 luminaires. The best available techniques were evaluated over the last few years. Out of a range of different smart lighting control systems, LED were chosen and used for retrofitting the existing T8 luminaires or simply replacing them with new dedicated LED luminaires. The study analyzed five different lighting setups for upgrading the existing fluorescent T8 2*36W luminaires. One setup used T5 lamps and the others used retrofitted or dedicated LED lighting solutions. First the lighting quantities of each setup were evaluated under real and experimental conditions. Second, a programable power source was used for measuring power quality indicators corelated with the provided lighting outputs, under different voltage values and waveforms. For each lighting setup, an even and odd current harmonic limit check was performed in line with class C—lighting equipment, IEC 61000-3-2 requirements. A new energy efficiency and power quality indicator was proposed—the lighting apparent power density [VA/sq.m/100lx].

Product Design, Robotics, Advanced Mechanical and Mechatronic Systems and Innovation Conference

PRASIC 2018, 8 – 9 November 2018The 10th edition of the PRASIC Conference was hosted in Brasov on 8-9 November 2018.The PRASIC‘18 Conference is dedicated to scientific research in the field of mechanics, machine elements, industrial robots, advanced mechanics and mechatronic systems, tribology, and also in education, innovation and technology transfer, industrial management, mechanics and machine history.The beginning was in 1982 under the name of PRASIC (Computer Aided Design), at the initiative of Professor Ioan Drăghici. At the beginning only the scientific researches related to Mechanisms and Machine Elements were treated, from 1996 Robotics was added, and then other scientific concerns related to them.In 2006, it was the last edition having as sections mechanisms, Machine Elements and Robotics. In 2016 PRASIC was renamed, being Product Design, Robotics, Advanced Mechanics & Mechatronic Systems, and Innovation Conference, keeping the brand PRASIC, well known in Romania and also outside, having an important history, and also keeping a high quality standard for scientific papers.At the 2018 edition, 48 papers were selected on 9 sections, with the participation of colleagues from university centers such as: Politehnica University of Bucharest, Gh. Asachi Iasi University, Technical University of Cluj Napoca, Stefan cel Mare University of Suceava, University Constantin Brancusi Tg. Jiu, Dunarea de Jos University of Galati, Politehnica University of Timisoara, University of Craiova, Petroleum and Gas University of Ploiesti, Technical University of Moldova Chisinau.The scientific opening of the Conference was provided by Professor Alberto Canen of Coppe University, Rio de Janeiro, Brazil and Professor Valeriu Dulgheru of the Technical University of Moldova. Conference papers were submitted for publication at the IOP Publishing Conference Series - Materials Science and Engineering.Organizing Committee,Professor Dan SĂVESCU

Research on improving the accuracy of FDM 3D printing process by using a new designed calibrating part

The article presents theoretical and experimental research methods that were used at the Technical University of Cluj-Napoca (TUCN) to improve the accuracy of Fused Deposition Modeling (FDM) 3D printing process. Finite element analysis method was successfully used for estimating the shrinkages of an original calibrating part that has been originally conceived for this purpose, this part being finally made using an original software application and FDM 3D printing equipment at TUC-N.