RFOS - Repository of Faculty of Organizational Sciences Univ. of Belgrade
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Minimal 3-triangulations of p-toroids
No full textIt is known that we can always 3-triangulate (i.e. divide into tetrahedra with the original vertices) convex polyhedra but not always non-convex ones. Polyhedra topologically equivalent to ball with p handles, shortly p-toroids, cannot be convex. So, it is interesting to investigate possibilities and properties of their 3-triangulations. Here we study the minimal number of necessary tetrahedra for the triangulation of a 3-triangulable p-toroid. For that purpose, we developed the concept of piecewise convex polyhedron and that of its connection graph
q-Rung orthopair fuzzy hypersoft ordered aggregation operators and their application towards green supplier
No full textGreen Supply Chain Management (GSCM) is essential to ensure environmental compliance and commercial growth in the current climate. Businesses constantly look for fresh concepts and techniques for ensuring environmental sustainability. To keep up with the new trends in environmental concerns related to company management and procedures, Green Supplier Selection (GSS) criteria are added to the traditional supplier selection processes. This study aims to identify general and environmental supplier selection criteria to provide a framework that can assist decision-makers in choosing and prioritizing appropriate green supplier selection. The development and implementation of decision support systems aimed to solve these difficulties at a rapid rate. In order to manage inaccurate data and simulate decision-making problems. Fuzzy sets introduced by Zadeh, are a useful technique to handle the imperfectness and uncertainty in different problems. Although fuzzy sets can handle incomplete information in different real worlds problems, but its cannot handle all type of uncertainty such as incomplete and indeterminate data. Therefore different extensions of fuzzy sets such as intuitionistic fuzzy, pythagorean fuzzy and q-rung orthopair fuzzy sets introduced to address the problems of uncertainty by considering the membership and non-membership grade. However, these concepts have some shortcomings in the handling uncertainty with sub-attributes. To overcome this difficulties Khan et al. developed the structure of q-rung orthopair fuzzy hypersoft sets by combining q-rung orthopair fuzzy sets with hypersoft sets. A remarkable and beneficial research work is done in the field of q-rung orthopair fuzzy hypersoft sets, and then we think about the application. In this paper, we use the structure of q-rung orthopair fuzzy hypersoft in multi-criteria supplier selection problems. For this, we present aggregation operator to solve multi-criteria decision-making (MCDM) problems with q-rung orthopair fuzzy hypersoft (q-ROFH) information, known as ordered weighted geometric aggregation operator. Since the uncertainty and vagueness is an unavoidable feature of multi-criteria decision-making problems, the proposed structure can be a useful tool for decision making in an uncertain environment. Further, the expert opinions were investigated using the multi-criteria decision-making (MCDM) technique, which helped identify interrelationship and causal preference of green supplier evaluation aspects that used aggregation operators. Finally, a numerical example of the proposed method for the task of Green Supplier Selection is presented
Characteristics of Spreadsheet-Based Shadow IT in Serbian Companies
No full textModern business of the digital age brings numerous opportunities, but also imposes challenges and carries a risk for companies. The amount of data generated via multiple sources, which characterize the embraced Industry 4.0, could be considered as an incredible chance for process improvement, but also it is a source of tasks that are not easy to complete. A necessity for quick response to business changes often collides with general information systems features and functions. The lack of fit of official information systems with users' requirements frequently implies occurrence of Shadow IT. Shadow IT is still an emerging topic, although gaining more attention in the previous decade. This paper aims to examine shadow IT existence and its characteristics in companies operating in the Republic of Serbia. A systematic literature review was performed to identify papers that cover the topic of shadow IT in the Republic of Serbia. The following electronic databases were searched: Web of Science, Scopus, COBISS.SR and Google Scholar. Based on the literature review, the most frequently occurring form of shadow IT in the Republic of Serbia is outlined, along with accompanying positive and negative consequences. Given the literature review, the authors proposed risk mitigation suggestions related to spreadsheet education improvements
IMPACT OF ONLINE INFORMATION AND REVIEWS ON PARTICIPATION IN THE COLLABORATIVE ECONOMY: THE EXAMPLE OF CARPOOLING
No full textImajući u vidu da je u osnovi kolaborativne ekonomije (engl. collaborative economy) da se, kroz
platformu, omogući direktna veza između korisnika i provajdera, pitanje poverenja predstavlja “valutu” ovog
koncepta. Brojni su digitalni indikatori koji doprinose izgradnji poverenja među učesnicima ekonomije deljenja.
Za potrebe ovog rada izučavane su one grupe faktora koje doprinose stvaranju interpersonalnog poverenja (tzv.
interpersonal trust) kroz informisanje i elektronsku neformalnu komunikaciju (electronic Word‐Of‐Mouth,
eWOM). Rad ima za cilj da utvrdi postojanje razlika u stvaranju interpersonalnog poverenja kod korisnika
kolaborativne ekonomije (na primeru BlaBlaCar platforme) i kod onih koji to nisu, kao i identifikovanje
komponenti koje posebno (ne)doprinose izgradnji tog poverenja. Anketiranjem 120 ispitanika uočeno je da samo
oni pojedinci koji imaju iskustva u konceptu zajedničke vožnje prepoznaju ulogu i značaj platforme i svih
informacija koje pronalaze na njoj, odnosno da pojedincima koji nisu korisnici platforme recenzije i rejtinzi drugih
korisnika ne znače puno već svoje poverenje vezuju za ljude koje poznaju i nije im bliska ideja poverenja u
tehnološki sistem.Taking into account that the basis of the collaborative economy is to enable a direct connection
between users and providers through the platform, the issue of trust is the “currency” of this concept. There are
numerous digital indicators that contribute to building trust among participants in the sharing economy. For the
purposes of this paper, a group of factors that contribute to the creation of interpersonal trust through
information and electronic informal communication (electronic Word‐Of‐Mouth, eWOM) were studied. The aim
of the paper is to determine the existence of differences in the creation of interpersonal trust among users of
the collaborative economy (on the example of the BlaBlaCar platform) and among those who are not, as well as
identifying the components that especially (do not) contribute to building that trust. By surveying 120
responden,ts it was observed that only those individuals who have experience in carpooling recognize the role
and importance of the platform and all the information they find on it, i,.e. that to individuals who are not users
of the platform, user reviews and ratings do not mean much, but they place their trust in people they know and
they are not close to the idea of trusting the technological system
A Data Streaming Architecture for Air Quality Monitoring in Smart Cities
No full textThis paper aims to present a modeling approach for the seamless data streaming process from smart IoT systems to Apache Kafka, leveraging the MQTT protocol. The paper begins by discussing the concept of real-time data streaming, emphasizing the need to transfer data from IoT/edge devices and sensors to Apache Kafka in a timely manner. The second part consists of a literature overview that shows the analysis and systematization of different types of architectures in the broad sense of crowdsensing, followed by specific architectures regarding edge and cloud computing. The methodology section will propose an infrastructure and data streaming architecture for smart environment services, such as air quality monitoring. Lastly, a discussion about results and future development will be shown in the last two sections. The proposed integration approach offers several advantages, including efficient and scalable data streaming, real-time analytics, and enhanced data processing capabilities
PRIMENA AUKCIJA KAO PODSTICAJ ZA INVESTICIJE U OBNOVLJIVE IZVORE ENERGIJE
No full textSistem podsticaja za proizvodnju električne energije iz obnovljivih izvora energije doživeo je velike promene u prethodnoj deceniji. Usled sve većeg finansijskog opeterećenja za potrošače i javne finanasije, većina zemalja Evropske unije je zamenila sistem baziran na feed-in tarifama sistemom aukcija i tržišnih premija. Zahvaljujući tome, ostvaren je značajan napredak u korišćenju obnovljivih izvora energije uz značajno manje troškove. U Srbiji sistem feed-in tarifa je na snazi od 2013. godine. Od početka implementacije ovih mera učinjen je značajan napredak u razvoju energetskog sektora i iskorišćenosti potenicijala obnovljivih izvora energije. S obzirom na veliko buđžetsko opterećenje, najavljen je prelazak na sistem aukcija i tržišnih premija
Application of Smart Contracts in Supply Chain Management
No full textTraditional supply chain management systems can struggle with issues such as traceability, transparency and trust between supply chain participants. In order to mitigate such issues, we propose application of blockchain technology and smart contracts. This paper presents a working supply chain model based on the Ethereum blockchain network. Ganache, a personal Ethereum blockchain, was used to deploy contracts, and TruffleSuite was used as a development environment. Although participants in the supply chain are simplified in comparison to real world scenarios, the presented model allows us to demonstrate how application of blockchain and smart contracts can improve mentioned issues characteristic for traditional supply chains. Detailed process flow of such a supply management system was given, and used system structures were described in detail. Described model proves that it is possible to apply smart contracts in order to solve problems of traceability transparency and trust in a simple and reliable way
A complex spherical fuzzy CRADIS method based Fine-Kinney framework for occupational risk evaluation in natural gas pipeline construction
No full textOccupational risk evaluation is one of the most indispensable issues in the risk prevention and control process for the natural gas pipeline construction (NGPC) project. The Fine-Kinney model, recognized as an effective occu-pational risk evaluation technique, has limited capability to handle the occupational risk analysis problem under the complex spherical fuzzy (CSF) environment. Accordingly, a synthetical Fine-Kinney framework based on the compromise ranking of alternatives from distance to ideal solution (CRADIS) method is developed to overcome these downsides of occupation risk analysis in the NGPC project within the CSF context. A prioritized weighted average (PWA) operator for complex spherical fuzzy numbers (CSFNs) is incorporated into the group risk evaluation matrix generation process, which can take the priority degrees of experts into account. Then, the extended CRADIS method-based Fine-Kinney framework is generated, in which the Choquet integral for CSFNs is incorporated to reflect the impact of interactive risk factors. Next, the detailed solution procedures of the framework for handling the occupational risk evaluation problem are presented. Finally, the described frame-work is employed as an empirical example of occupational risk analysis for the NGPC project to demonstrate its feasibility in practice. After that, a sensitivity analysis of the parameter is investigated to testify to the stability and rationality of the reported synthetical Fine-Kinney framework. Subsequently, to further display the advan-tages of the developed Fine-Kinney framework, a comparative study is implemented to discuss the evaluation result of occupational risk derived from the proposed framework and those of the existing similar Fine-Kinney frameworks. The analysis results indicate that the occupational risk (attack by human or animal) with the maximum risk priority value (1.000) using the framework is identified as the most serious risk for the NGPC project
Spacecraft tracking control and synchronization: An assessment of conventional, unconventional, and combined methods
No full textArtificial intelligence (AI) promises breakthroughs in space operations, from mission design planning to satellite data processing and navigation systems. Advances in AI and space transportation have enabled AI technologies in spacecraft tracking control and synchronization. This study assesses and evaluates three alternative spacecraft tracking control and synchronization (TCS) approaches, including non-AI TCS methods, AI TCS methods, and combined TCS methods. The study proposes a hybrid model, including a new model for defining weight coefficients and interval type-2 fuzzy sets based combined compromised solution (IT2FSs-CoCoSo) to solve the spacecraft TCS problem. A new methodology is used to calculate the weight coefficients of criteria, while IT2FSs-CoCoSo is applied to rank the prioritization of TCS methods. A comparative analysis is conducted to demonstrate the performance of the proposed hybrid model. We present a case study to illustrate the applicability and exhibit the efficacy of the proposed method for prioritizing the alternative TCS approaches based on ten different sub-criteria, grouped under three main aspects, including complexity aspects, operational aspects, and efficiency aspects. AI and non-AI methods combined are the most advantageous alternative, whereas non-AI methods are the least advantageous, according to the findings of this study
The benefit of reflection prompts for encouraging learning with hints in an online programming course
No full textWhile giving learners hints is a commonly used scaffolding practice to facilitate learning, previous work ques-tioned the effectiveness of hints. In this study, we examined if prompting learners to reflect along with receiving hints could improve learning outcomes, including immediate and delayed performance, perceived learning, and enjoyment. A field experiment was conducted in a four-week long online master's degree course on data science where we compared two conditions: a condition with hints and a condition providing reflection prompts along with hints. Results showed that using hints with reflection prompts increased learner performance in delayed knowledge transfer tasks while also increasing learners' perception of learning. The combination of reflection prompts and hints did not reduce learners' enjoyment of the tasks, suggesting that the use of hints with reflection prompts is not only an intervention which can improve learning outcomes but is one which will be naturally adopted by learners