Tomaž Berlec | University of Ljubljana (original) (raw)

Papers by Tomaž Berlec

In this paper an IoT application of LoRa is presented. The application is related to the socalled... more In this paper an IoT application of LoRa is presented. The application is related to the socalled precision beekeeping. This term is associated with the monitoring of many variables within a hive and in its vicinity, which can assist the beekeeper at all the activities that have to be done in beekeeping practice. In order to achieve that kind of functionality the so called wireless sensor network has to be realized. First an overview of such technologies is given. Our decision was to take LoRa. The core of the system is an Arduino microcontroller with the addition of the LoRa shield. In the paper a process of communication between master and slave unit is described. In order to demonstrate the applicability, the slave unit has an additional temperature sensor attached. The system was verified by a successful temperature measurement lasting several days.

2023 IEEE 32nd International Symposium on Industrial Electronics (ISIE)

International Journal of Simulation Modelling, 2021

When building a new company or optimising an existing one, material handling (MH) is often forgot... more When building a new company or optimising an existing one, material handling (MH) is often forgotten. Therefore, the paper presents a decision tree, on the basis of which it is possible to select the most suitable MH system by simulation depending on the selected production parameters. Such a simulation can greatly facilitate the selection of the most suitable MH system which will ensure minimal time consumption and still acceptable costs. To perform the simulation, a generalised production system model for 5 different MH systems was created in the FlexSim software, with which 32 different scenarios could be simulated depending on the selected production parameters, tested in a production facility of injection moulded components for the automotive industry. The data obtained from the simulations were then used to analyse the influence of the selected parameters on possible MH systems. For all potential scenarios, the solutions of which are acceptable for MH, a cost-benefit analysis was performed. Based on the analysis, a difference of 75 % between the most and least favourable scenarios was established.

Computers & Industrial Engineering

Applied Sciences

This study investigates the effects of blockchain technology scalability limitations on the perfo... more This study investigates the effects of blockchain technology scalability limitations on the performance of Blockchain-Based Shared Manufacturing (BBSM), an innovative smart-manufacturing paradigm aimed at enhancing the utilization of global manufacturing resources via peer-to-peer (P2P) collaboration of self-organized manufacturing assets. Despite the prevalence of research highlighting blockchain technology’s scalability limitations as the main barrier for adoption, few studies have explored their effects on the operation of blockchain-based systems. The primary goal of the presented research work is to explore the implications of blockchain technology scalability limitations on the BBSM system’s performance and user behavior. To obtain realistic behavior, an experiment is conducted using an online game played by human participants. Analysis of the players’ strategy is used for implementation of a multi-agent simulation model, which is then employed to assess the influence of varyi...

Strojniški vestnik, 2005

Companies are nowadays confronted with new challenges: simultaneously they are dealing with the g... more Companies are nowadays confronted with new challenges: simultaneously they are dealing with the globalization of business and acting on local markets, the standardization and customization of products for fastidious customers and increased competition. In these circumstances the only successful companies are those which can respond quickly to market changes, i.e., they have a short response time for the fulfilment of customer requirements (a short delivery time and reliable delivery in addition to a competitive price and high quality). Consequently, a reduction of the mean inventory, the range and the lead time of the working systems in the company is an ever increasing strategy that ensures the customer 's satisfaction and an increase in growth and profit for the company. The article shows how the tools for modelling the flow of orders through working systems can be used to find and exploit the hidden logistic potentials of working systems in a company. Here we present the resu...

Strojniški vestnik - Journal of Mechanical Engineering

More recent research shows the significant impact of accurate demand forecasting on the operation... more More recent research shows the significant impact of accurate demand forecasting on the operation of supply chain system and thus on the performance of the company. Inventories in the production process could represent waste, which results in higher storage costs and consequently a higher product price, which in turn reduces company's competitiveness on the market. Nevertheless, a company must implement a lean production process and consequently carefully control storage and inventory costs. The introduction of a lean production process is closely linked to the risk of stock-outs, and knowledge of this risk in relation to customer habits is therefore a useful piece of information for the line manager's decision-making. This paper will present a mathematical model that relates customer demand for a product to the inventory level in the warehouse or between the work operations of the production process and the risk of potential penalties that arises with the introduction of a ...

J. Integr. Des. Process. Sci., 2014

An extended risk-analysis procedure for new product/service realisation projects is presented in ... more An extended risk-analysis procedure for new product/service realisation projects is presented in this paper. The usual risk analysis of project activities is based on evaluation of the probability that risk events occur and on evaluation of their consequences. Product/process realisation projects are cyclically recurring, so the third parameter has been added in the proposed procedure: an estimate of the incidence of risk events. On the basis of the calculated activity risk level in a three-dimensional risk analysis, a project team prepares preventive and corrective measures that should be taken according to the status indicators. An important advantage of the proposed solution is that the project manager and team members also take into account the recurring risk events in risk management. By successive elimination of sources of recurring risk events, the three-dimensional risk analysis of project activities can be transformed to the well-known two-dimensional risk analysis. A templ...

SOR '21 proceedings, 2021

Business Systems Research Journal, 2020

Background: To stay competitive in a highly unpredictable market of today, companies must be able... more Background: To stay competitive in a highly unpredictable market of today, companies must be able to manage project risks effectively. The basis for an effective risk management is a thorough risk analysis. Despite the availability of many different risk analysis approaches, companies can be reluctant to use them, since the models are usually complex and very time consuming. Objectives: The main objective is to present a simple, yet effective risk analysis approach that can also serve as a useful basis for resolving project risks. Methods/Approach: The proposed standard risk analysis approach is based on a standard risk model that deals with risk events and impacts separately and therefore allows for a separate planning of preventive and corrective measures. To classify risks and to represent them graphically, a risk map is used. Results: The use of the proposed approach is illustrated on a die-cast tool development project. The approach proved to be very simple to use and it served...

Applied Sciences, 2022

Giving an offer to a consumer and knowing the average cost of the product (ACP) for the product a... more Giving an offer to a consumer and knowing the average cost of the product (ACP) for the product along the entire production process, depending on the size of the order, can be a very important indicator which also has an impact on the lean production process. This paper presents a mathematical model to analyze the impact of customer changes (changes in the product type, quantity and/or quality) on the lean production process, and thus on the average production price (ACP). Any change in the process could mean a deviation from the lean process, which means an increase of the ACP for the company, which is the main goal of Industry 4.0. The measurements can be performed on all of the operations of the production process in a company, or only the most critical operations in terms of waste can be selected. The model was tested on an example of a product from a Slovenian company. The average cost of the product in the selected work operation turned out to be 71% higher than the optimal ca...

International Journal of Simulation Modelling, 2020

Value stream mapping (VSM) is based on an analysis of the times required to carry out production ... more Value stream mapping (VSM) is based on an analysis of the times required to carry out production processes throughout the customer-manufacturer-supplier logistics chain. The goal of VSM is to identify wastes and eliminate them, thereby increasing the added value of a product. The paper presents an extension of the VSM concept which is based on determining the costs associated with the necessary operations and determining, based on said costs, the total costs of the entire production process. When eliminating those activities that represent waste, we can, by simulating the total costs, determine the contribution of the implemented measure to the reduction of lead time and, above all, the reduction of costs and thus the economic efficiency of the production process. For the presentation, by simulating the identified cost effects of the anticipated changes, we can calculate the leanness cost index and, using portfolio analysis of the leanness of the production system, analyse the effects. The application of the proposed methodology is shown in the case of transition from individual to lean and agile series production of ceramic capacitors.

Sustainability, 2020

In today’s highly dynamic and unpredictable project environment, companies need to be able to man... more In today’s highly dynamic and unpredictable project environment, companies need to be able to manage changes quickly and effectively, otherwise, the final product will not be current and will only go to waste. Traditional project management approaches that focus on planning are no longer efficient and companies are forced to adopt new ways of working. As a result, more flexible agile project management (APM) approaches have emerged over the last decades. Originally developed for the software industry, APM is now increasingly recognized and adopted also by other industry sectors. However, due to some discipline-specific differences, the adoption of APM by non-software companies is challenging and requires many adjustments and high financial input. While the larger organizations have sufficient resources to make such a transition, small and medium-sized enterprises (SMEs) generally cannot afford to do so, and therefore need alternative strategies to increase their agility and stay com...

Theory and Application on Cognitive Factors and Risk Management - New Trends and Procedures, Jun 21, 2017

In projects of development and industrialization of new products or to improvement of the existin... more In projects of development and industrialization of new products or to improvement of the existing ones not only quality and costs but also the time of product entering the market and delivery time to the client are important. This can be achieved by efficient project management, where classic methods of project management need to be upgraded by elements of concurrent engineering. In this chapter, a method for risk management in cyclically recurrent projects is demonstrated, in which conventional models of risk management based on an assessment of probability of risk event occurrence and an assessment of their consequences are supplemented by a third parameter-assessment of frequency of recurrence of risk events. An important advantage of the suggested solution lies in that a project manager and team members take into account cognitive factors, when managing recurrence of risk events which are usually due to poorly organized business processes of a company. A template was created in the Microsoft Project environment, by means of which the project team tested the suggested methodology on an example of concurrent realization of a pedal assembly of a car.

Strojniški vestnik – Journal of Mechanical Engineering, 2014

International Journal of Simulation Modelling, 2016

An analysis of a product line of small and medium-sized enterprises (SME) shows that products (co... more An analysis of a product line of small and medium-sized enterprises (SME) shows that products (component parts or assemblies) are quite similar in terms of design and technology, thus clusters of products are formed. For each cluster a production cell can be organized. According to the product line of a company a certain number of individual production cells is organized, while workshop production is retained for the remaining product line. The paper shows how clusters of products are designed on the basis of a product line data and how an ideal layout optimization is determined on the basis of the intensity of material flow. Layout optimization of a production cell is based on a combination of Schmigalla modified triangular method and the Schwerdfeger circular process. The method was applied on a cluster of 20 orders similar in design and technology that are processed at 10 workplaces. At the end of the article a transition from a theoretical O-cell to a real U-cell is suggested.

– The paper presents a procedure for forecasting the lead times of production orders on the basis... more – The paper presents a procedure for forecasting the lead times of production orders on the basis of past actual lead time data. A customer for a particular production order will select the best bidder. It is rather risky to make a bid just on the basis of sales experience. A procedure is therefore proposed by which, on the basis of the actual lead times of operational and assembly orders processed in the company's workplaces in the past, the expected lead time of a planned production order can be forecasted. The result of the proposed procedure for forecasting lead times is an empirical distribution of possible lead times for a production order. On the basis of this distribution, it is possible to forecast the probable lead time of a production order, taking into account a confidence interval. Using the proposed procedure, the sales department can make a delivery time forecast for the customer of the planned production order. As an illustration of using the procedure for forec...

Sustainability

In order to survive in today’s highly competitive global market, small and medium-sized enterpris... more In order to survive in today’s highly competitive global market, small and medium-sized enterprises (SMEs) have had to transition from sequential to concurrent product development, which significantly shortens development cycles, reduces costs, and ensures high product quality. Despite its many benefits, concurrent product development is still based on detailed upfront planning and cannot address the challenges related to today’s ever-growing uncertainty, constantly changing environment, and unstable requirements. A potential solution to this problem could be in more flexible and value-driven agile project management (APM) approaches, typical of software development. In this paper, we propose a new product development model specifically appropriate for SMEs that combines concurrent product development principles with APM elements. It is designed as a loop of five repetitive steps (macroplan, microplan, iteration activities, review, and retrospective) that are being executed within i...