Papers by Stanislav Dimitrov
Mathematics, Apr 22, 2024
2021 XXX International Scientific Conference Electronics (ET), 2021
Farms have different activities, such as raising different types of animals or focusing on develo... more Farms have different activities, such as raising different types of animals or focusing on developing different branches of crop production, and very often they combine livestock and crop production activities to reduce their financial losses. On large farms, animal husbandry is just one of their activities. From the perspective of complex systems, the agricultural holding can be considered as a multi-feedback system, which includes a subsystem for crop production, a subsystem of the household and a subsystem for animal husbandry. Livestock, when considered as a production process, can be presented as a network of actions, the links between them and criteria for their identification. One of the main costs for livestock farms is the cost of food supplements. The paper presents the possibility of applying a mathematical model for stock management of feed additives for pig nutrition as well as its implementation through an Internet-based application. This creates a local and global information advisory module for the farmer to make a decision when managing a food supplement storehouse.
WSEAS transactions on business and economics, May 31, 2024
2022 8th International Conference on Energy Efficiency and Agricultural Engineering (EE&AE), Jun 30, 2022
2020 International Conference Automatics and Informatics (ICAI)
The rising number of people working and living in big cities around the world, many of which own ... more The rising number of people working and living in big cities around the world, many of which own a personal car, lead to a well-known social problem, namely, traffic congestions. Congestions occur when a large number of road traffic participants aim to use the very same infrastructure, while the latter has limited capacity. This situation entails a number of negative consequences, such as slow motion, economic losses, environmental pollution, safety problems and road accidents. The implementation of appropriate transport infrastructure management can make traffic more efficient, safer and greener.Traffic management in an urban environment is mainly realized through traffic light management. It is an integral part of the intelligent transport system (ITS), which is essential for facilitating traffic congestion. Poor traffic management and inefficient settings at signalized intersections cause many problems such as excessive delays for vehicles, increased fuel consumption and CO2 emissions generated by transport means. The efficiency of signalized intersections can be significantly improved by optimizing phase duration and synchronizing traffic lights using intelligent traffic management methods. For this reason, the paper demonstrates the use of the built-in Excel GRG Nonlinear Multi-start application for improving the level of service (LOS) in intersection by optimizing the phase length and cycle of two isolated traffic lights. The average weighted controlled vehicle delay at the intersection is the indicator for assessing the effectiveness of the objective function. The results of the study show that the calculated values for delays for passing through intersections have decreased.
Report published in the Proceedings of the National Conference on "Education and Research in... more Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, June, 2018The article explores the application of educational games over the last five years in Bulgarian schools. The trends in the change of different aspects in this field are traced, focusing on the attitude of the teachers to the gaming educational resources. Self-assessments of teachers' competence for the use of ICT in learning purposes, their willingness to engage in developing such learning materials, and the appropriate age for introducing educational games into learning are presented. Teachers' views on their role in the use of games, their usefulness, and their impact on various aspects of school education in Bulgaria are traced.Association for the Development of the Information Society, Institute of Mathematics and Informatics Bulgarian Academy of Sciences, Plovdiv University "Paisii Hilendarski
Proceedings of the 21st International Conference on Computer Systems and Technologies, 2020
Increasingly, analytical methods such as mathematical modeling, statistical analysis and mathemat... more Increasingly, analytical methods such as mathematical modeling, statistical analysis and mathematical optimization are used in the management of real objects to establish optimal solutions to complex decision-making problems [1]. Among the mathematical modeling approaches, the technique of linear programming boasts with widest application. In it, the criterion for the effectiveness of the model is a linear objective function, which must be maximized or minimized in compliance with certain linear constraints. This technique allows to make a quantitative assessment of decisions on real problems in various areas such as finance, production, sales and distribution, transport, personnel management, marketing and others. Linear programming tasks aim to achieve optimal allocation of limited resources under certain constraints. Resources can be raw materials, labor, machinery, time, money, while constraints can be the company's possible costs or available raw materials. For many organizations, it is crucial to ensure good planning and distribution of the workforce, thus reducing costs and achieving more efficient use of resources, as well as fairer workload. Transport companies make no exception in that respect. Transport service operators need to plan the number of drivers and the number of vehicles correctly in order to comply with their timetables. These two problems are well described in the literature and are known as Crew Scheduling Problem (CSP) and Vehicle Scheduling Problem (VSP), respectively. The aim of resolving them is to minimize the operating costs regarding the use of vehicles and drivers' salaries in case of operational restrictions for vehicles and labor regulations for drivers, and to increase the quality of the offered service [2], [3], [4]. Concentrating on these problems allows reaching a relatively easy and effective solution. However, it should be mentioned that the results obtained may not fully satisfy the requirements of transport service operators. Other disadvantages in solving such a class of tasks is that the applied methods are susceptible to interference by dispatchers and they can compromise the resulting solutions. The complexity and size of the tasks are time consuming in reaching an optimal solution and require a large amount of hardware resources. The problem is common and is solved by transport companies operating in different countries. It also concerns Bulgarian public transport operators, according to publications in the media [5], [6]. This reaffirms the need to approach the problem with the help of mathematical tools and offer a management option for this socially significant issue. The paper presents two consecutive tasks for optimal allocation of resources in the transport system. Both tasks are examples of demand modeling. The first task aims to calculate the number of tram drivers in each work shift needed to complete the daily schedule of the tram lines. The second task aims to calculate the number of employees for whom the working week starts from the respective day, so that their total number is minimal. The branch and bound approach is used. It is consisted of a series of subproblems for solving mixed and integer problems. They are solved systematically until the best solution to the main problem is found. Problems are solved with the Matlab program, using the intlinprog function. Then, a modification of the resource allocation tasks is presented. It examines several time ranges for many tram lines (for the first task - different work shifts; for the second task - days of the week). The remainder of the paper is organized as follows. The specific problem is described in Section 1. The mathematical modeling is given in Section 2. In Section 3 an algorithm and a script for optimal distribution of tram drivers are described. The computational results are presented in Section 4 and the paper is finalized with conclusions in Section 5.
The Challenges of the Digital Transformation in Education, 2019
Contemporary information and communication technology (ICT) and its applications are not only bec... more Contemporary information and communication technology (ICT) and its applications are not only becoming an integral part of the everyday life of our society but also standard in most of the schools across the globe. Furthermore, the technology integration offers a qualitative transformation of all components of educational process. As innovative tools are getting an important requisite for all kind of educational institutions, the researchers should be aware of their influence on teaching and learning processes. This paper presents parts of the outcomes from a massive survey aimed at investigation of ICT integration in Bulgarian schools. In order to assess the acceptance of technology resources and their institution-wide adoption, it is important to understand teachers and students’ perceptions on the technology-enhanced teaching. It is essential to find out to what extent the teachers’ practice is in line with the expectations of the students. The research of dynamics of this issue ...
2021 12th National Conference with International Participation (ELECTRONICA), 2021
Traffic congestion is a problem in large cities. It has many negative consequences for the econom... more Traffic congestion is a problem in large cities. It has many negative consequences for the economy, the environment and human health. Proper adjustment of the traffic light settings in urban environments is the main means of control of this problem. This paper investigates a network of crossroads situated in central Rome in the area of Municipo V. The study presented in this paper offers alternative approaches to the optimization of signal timings of traffic lights in the network. A comparison is made between the current settings, the Buyanov et al. optimization approach, the nonlinear optimization approach and the bi-level optimization approach. Signal timings for the current settings and for the three optimization approaches are imported in the traffic simulation software suit Aimsun and the output results of the four simulations are compared. The analysis and evaluation of the output data shows that the nonlinear approach gives better results than the Buyanov et al. approach. This is also valid for the bi-level optimization approach. The effectiveness of the used optimization methodologies is graphically presented.
2021 Big Data, Knowledge and Control Systems Engineering (BdKCSE), 2021
The global trend is for the size of farms to increase, which leads to a deterioration in the qual... more The global trend is for the size of farms to increase, which leads to a deterioration in the quality of their products, workforce, efficiency. One way to deal with this problem is to use various technologies, including information technology in the production process. Software products on the market rarely have a predictive module. For this reason, the article explores the possibility of developing different models for forecasting data on the demand for products produced on a farm using the MS Excel product.
SHS Web of Conferences
A quantitative analysis of the financial state of an animal husbandry is performed. The paper ill... more A quantitative analysis of the financial state of an animal husbandry is performed. The paper illustrates the usage of different economical parameters in order to present operational state of the husbandry and to search regularities for future actions. The added value of this research is the application of intelligent instruments in the management of the economic behavior of animal husbandry which give recommendations for their more effective functionality.
2022 8th International Conference on Energy Efficiency and Agricultural Engineering (EE&AE)
2021 International Conference Automatics and Informatics (ICAI), 2021
A quantitative analysis based on the method of correlation analysis of the financial state of ani... more A quantitative analysis based on the method of correlation analysis of the financial state of animal husbandry is performed. The paper illustrates the usage of different economic parameters in order to estimate correlations between the disbursements and cash receipts annually. The provided analyzes of risks per categories and their relations with the received incomes give explicit views about the effective operation of the husbandry. The added value of this research is the decision making support by intelligent quantification modeling for the management of the economic behavior of animal husbandry
Cybernetics and Information Technologies, 2021
The urban traffic control optimization is a complex problem because of the interconnections among... more The urban traffic control optimization is a complex problem because of the interconnections among the junctions and the dynamical behavior of the traffic flows. Optimization with one control variable in the literature is presented. In this research optimization model consisting of two control variables is developed. Hierarchical bi-level methodology is proposed for realization of integrated optimal control. The urban traffic management is implemented by simultaneously control of traffic light cycles and green light durations of the traffic lights of urban network of crossroads.
2021 12th National Conference with International Participation (ELECTRONICA), 2021
An application of information technologies support for traffic lights control is presented. The c... more An application of information technologies support for traffic lights control is presented. The control task is formalized as a bi-level hierarchical problem solved in MATLAB environment. The traffic lights control is applied for a network of eight crossroads in the urban area of Sofia. The optimization problem is numerically tested with traffic intensity data and graphical interpretations are given. Comparison with the classical optimization control problem gives benefits for the bi-level optimization model.
Proceedings of the 14th International Conference on Computer Systems and Technologies, 2013
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EDULEARN18 Proceedings, 2018
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Papers by Stanislav Dimitrov