RFOS - Repository of Faculty of Organizational Sciences Univ. of Belgrade
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A Novel Decision-Making Process in the Environment of Generalized Version of Fuzzy Sets for the Selection of Energy Source
No full textIn this study, we focus our attention on a kind of generalized fuzzy set. This generalized fuzzy set is known as neutrosophic octahedron sets (NOSs). NOSs are a combination of neutrosophic, intuitionistic fuzzy, and octahedron sets that provide a better platform for dealing with imprecise and ambiguous data. First of all, we analyze uncertainty, for this purpose, we need neutrosophic octahedron set that can also reduce the loss of information about ambiguity and uncertainty. We use NOS over TOPSIS method (technique to order the performance by similarity with the ideal solution). It is a most suitable technique for describing uncertain data in the TOPSIS method in order to allow more imprecision than the neutrosophic, intuitionistic fuzzy, and octahedron set. Thus, the TOPSIS method of NOSs in decision making is used to overcome the problems that arise during decision-making. We use this proposed structure to implement the selection of the energy source by a numerical example as an application. As a result, this model is valuable for decision-making and can be used to choose the most environmentally friendly energy source. Finally, we present an example to demonstrate the validity and effectiveness of the proposed strategy
Tracking Students? Visual Attention During E-Learning in the Time of COVID-19
No full textThe COVID-19 virus pandemic has forced many educational institutions to use various platforms to conduct online classes. Online learning can hardly replace the classic form of teaching, and the involvement of students is often not at a satisfactory level. This paper researches the method of detecting students' attention during online learning based on monitoring eyes and face tracking. The analysis of the face, eye, and the probability of opening the right and left eye, enable the detection of the level of students' visual attention. The paper proposes a system that detects the visual attention of students by using a smartphones' camera and presents the experimental results obtained by using this system during the Covid-19 pandemic
Better confidence intervals for the slope parameters of the quadratic regression model when the error term is not normally distributed
No full textWhen the error term is not normally distributed, the confidence intervals for the slope parameters of the quadratic regression model, based on the ordinary t-statistic, are not appropriate. In this paper, we consider the interval based on the ordinary t-statistic and the intervals based on the resampling methods. Further, we derive the Edgeworth expansion of the distribution of the t-statistic. Based on that expansion we propose a new transformation of the t-statistic which is used for the construction of the bootstrap-t confidence interval for the slope parameter beta(2). The obtained results for the Gamma, Weibull, and Exponential distributions and for the real data set show that the intervals based on the resampling methods and the interval based on the new transformation of the t-statistic provide better coverage accuracy than the interval based on the ordinary t-statistic
Dynamic Discrete Inventory Control Model with Deterministic and Stochastic Demand in Pharmaceutical Distribution
No full textThis paper presents an inventory control problem in a private pharmaceutical distribution company from the Republic of Serbia. The company realizes that distribution within nine neighbouring countries and inventory control in the pharmaceutical supply chain is centralized. In order to constitute a conceptual model of the problem, we propose the modern control theory concept. The conceptual model is based on the specific practical assumptions and constraints of the supply chain. Thereafter, a dynamic discrete mathematical model of inventory control is formulated to reflect elements of the system and their relations. The model considers multiple pharmaceutical products, variable lead time, realized stochastics and deterministic demand, and different ordering policies (Lot for Lot and Fixed Order Quantity). Deterministic demand is represented as a sales forecast for each product per month, while stochastic demand is generated as a random variation of sales forecast in a range of +/- 20%. Two objective functions are defined as the maximization of the difference between planned average inventory level and realized average inventory level, and the minimization of stock-out situations. We develop a procedure for the determination of reorder points and the number of deliveries to achieve proposed objective functions. The model overcomes shortages of theoretically-based distribution requirements planning models and offers solutions to the limitations in inventory control practice. Real-life data, collected over two years, are used for the validation of the proposed model and the solution procedure. Numerical examples illustrate the model application and behaviour
Towards an Impartial Evaluation of Cities' Smartness: A Multivariate Statistical Approach
No full textThe issue of mapping the smartness of cities has attracted the attention of various stakeholders. One of the ways of quantifying city smartness and benchmarking cities based on the level of the achieved smartness is using composite indicators (CIs). However, the topic often cited as the slippery slope of CIs includes methodological issues when combining several indicators into one synthesized value. Aiming at providing a possible remedy to the subject, we employed the I-distance method to the PricewaterhouseCoopers (PWC) Cities of Opportunity Index. The results pointed out leader cities in terms of smartness, with the additional benefit of the study being encapsulated in much-needed inputs of essential components of the index. Consequently, decision-makers can foster the inputs of the study to raise the bar for a particular city
Strategic Importance and Sustainable Governance of High-Tech Business Incubators: Evidence from Serbia
No full textThis paper analyzes symbiotic relationship between high-tech start-ups, governance of business incubators dedicated to developing them and overall impact on Serbian economy and tech landscape. It was written based on previously conducted research, relevant industry reports, a review of academic literature and many articles on the business incubation. As high-tech business incubators are a part of economic development, this paper aims to examine the role of business incubator on SMEs and high-tech start-ups and explore which types of support drive this impact, but also to investigate impact on wider economic and social landscape in Republic of Serbia. Furthermore, the overall benefits of government investing in incubators are elaborated with review of private vs public ownership and differences in opportunities that they provide. The need for strategic governance and systematic support is rationalized by inspecting efficiency and effectiveness through large set of KPIs. Results should provide proper model for development of innovation ecosystem and entrepreneurship support by using business incubator as a tool. If managed properly, incubators can become a key component of national development strategy since they can help high-tech companies to survive and develop in MOST critical initial phase, by providing wide range of services such as management support, financial resources, technical services or simply offering adequate office space
Digital marketing in the promotion of a new fashion brand
No full textThe digital world has become an integral part of almost every industry, including fashion. Applying digital marketing in the fashion industry enhances brand recognition, enables access to the global market of customers and other stakeholders, and achieves engagement of customers in product development. Digital marketing can be defined as a form of direct marketing that connects the buyers with the sellers electronically using websites, social media, emails, mobile applications, etc. It enables easier and faster multichannel communication with customers and other stakeholders, and the promotion of products or services in a timely, relevant, personal and cost-effective manner.
In a world of fashion, where the environment is very dynamic and turbulent, it is important to meet customers’ needs and to customize fashion products according to them. That is where fashion marketing plays a major role because it operates through the whole supply chain of the fashion system. By appearing on the Internet, the fashion companies interact with customers in a more effortless and inexpensive way and establish with them a deeper relationship based on trust. It is very important to use omnichannel communication so that the customer does not feel alienated when using one of them. By implementing an omnichannel strategy, a fashion company can simultaneously meet customers’ expectations and make a profit by tailoring its resources to different channels depending on needs and opportunities.
The main aim of this research is the development of a methodological approach for the promotion of a new fashion brand based on a digital marketing strategy. This method should enable easier creation of the recognition of new fashion brands in the online market, reach the target audience, connect with stakeholders using omnichannel communication, and gain competitive advantages
Lean Approach to Lead Time Reduction in MTO Manufacturing: A Case Study
No full textIn order to improve operational performance, many companies adopted lean approach in their manufacturing processes. Although most of those companies revealed to be effective in lean implementation, small and medium-sized make-to-order (MTO) companies, faced with high mix and low volume production, had difficulties to implement lean. The mix of orders and the specific demands of every customer can increase the time from the placement of an order to the delivery to a customer. In that case, lead time can be long since the process typically includes steps such as ordering/sales, design, adjustment, procurement, production, assembly, delivery and installation. In order to reduce lead time in manufacturing processes, implementation of lean approach can be of great benefit. For that purpose, this paper analyzes lean approach applicability to MTO companies. The paper presents the implementation of lean in MTO manufacturing company that deals with the production of custom furniture. The results were obtained through systematic identification and elimination of wastes in all phases of the process, and show that significant lead time reduction can be achieved through lean implementation in MTO manufacturing
Model for Municipality Buildings Renting Auction on Algorand blockchain
No full textBlockchain is one of the vital supportive technologies of smart city services. Thanks to its characteristics, blockchain impacts almost all smart city services. Algorand network started working in 2019. Its speed of transactions and low cost makes it the platform of choice for a smart city blockchain implementation. This paper proposes a model for blockchain auction for renting real estate owned by the municipality. This service is part of the overall smart city services and relies heavily on other smart city governance services like identity information management, land register, and others. Implementing such a system simplifies the process of land and real estate management in the smart city making it more transparent. It lowers the costs and increases the income municipality earns from renting the asset
