1. Optimization of billet cooling after continuous casting using genetic programming—industrial studyMiha Kovačič, Aljaž Zupanc, Robert Vertnik, Uroš Župerl, 2024, original scientific article Abstract: ŠTORE STEEL Ltd. is one of the three steel plants in Slovenia. Continuous cast 180 mm × 180 mm billets can undergo cooling to room temperature using a turnover cooling bed. They can also be cooled down under hoods or heat treated to reduce residual stresses. Additional operations of heat treatment from 36 h up to 72 h and cooling of the billets for 24 h, with limited capacities (with only two heat treatment furnaces and only six hoods), drastically influence productivity. Accordingly, the casting must be carefully planned (i.e., the main thing is casting in sequences), while the internal quality of the billets (i.e., the occurrence of inner defects) may be compromised. Also, the stock of billets can increase dramatically. As a result, it was necessary to consider the abandoning of cooling under hoods and heat treatment of billets. Based on the collected scrap data after ultrasonic examination of rolled bars, linear regression and genetic programming were used for prediction of the occurrence of inner defects. Based on modeling results, cooling under hoods and heat treatment of billets were abandoned at the casting of several steel grades. Accordingly, the casting sequences increased, and the stock of billets decreased drastically while the internal quality of the rolled bars remained the same.
Keywords: billet cooling, continuous casting, ultrasonic testing, logistic regression, genetic programming, industrial study, steel making, optimization
Published in DKUM: 25.11.2024; Views: 0; Downloads: 10
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2. Sustainable developement in logistic : a strategy for management in terms of green transportDorota Klimecka-Tatar, Manuela Ingaldi, Matevž Obrecht, 2021, original scientific article Abstract: Supply chain management is one of the most important elements of sustainable development. And due to the fact that the world market is driven by supply and demand, and the determinant of access to products is regional and international logistics, this paper focuses on the possibilities of implementing a green transport strategy in the context of sustainable development in logistic enterprises. This paper presents the results of the SWOT anal-ysis pointing out the strengths, weaknesses, opportunities, threats of green vehicles market for the transport enterprises. It was noticed that the situation on the green vehicles market for the transport enterprises is charac-terized by the advantage of strengths and these strengths should be used to maximize the use of green vehicles. It emphasized that subsidies for green vehicles would allow to invest in a modern fleet, new solutions (e.g. own charging stations) can have an impact on the greater energy efficiency (self-sufficiency), increase of social aware-ness would force enterprises to take appropriate actions in the field of environmental protection and develop-ment of publictransport based on green vehicles.
Keywords: logistic enterprises, green transport strategy, green vehicles, SWOT analysis, environmental protection, sustainable development, green logistics, sustainability
Published in DKUM: 27.08.2024; Views: 66; Downloads: 6
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3. Attitude of motorists towards road ethics: empirical studyFunsho Idowu Obakemi, 2018, original scientific article Abstract: Road traffic safety among socioeconomic issues has become the major concern across the globe due to rise in road crashes attributed largely to human factor. This study tends to address attitudinal behavior of road users towards road ethics in Ilorin metropolis-Nigeria; covering both driver and motorcyclists and perception of motorists on road traffic enforcement agent. Questionnaire was employed as survey tools. Ordered logistic model were used to analyse the data on attitude of motorists and road traffic laws enforcement agents. About 87% of the 440 administered questionnaire were returned valid. A 3-model analysis was carried out and the findings showed that the attitude of the motorists, road traffic law enforcement agents and demographical index (gender, age and education) correlated with, and influence compliance with road traffic laws.
Keywords: road safety ethics, attitude & behavior, ABC-model, ordered logistic model
Published in DKUM: 22.08.2024; Views: 43; Downloads: 7
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4. Exploring factors afecting elementary school teachers' adoption of 3D printers in teachingBranko Anđić, Andrej Šorgo, Christoph Helm, Robert Weinhandl, Vida Lang, 2023, original scientific article Abstract: Owing to its advantages such as producing durable models and easy accessibility, 3D modeling and printing (3DMP) has become increasingly popular in educational practice and research. However, the results of many studies have shown that the adoption rate of 3DMP among teachers is still low, especially in elementary schools. Therefore, research is needed to expand current knowledge about what influences teachers' decisions to start and continue using 3DMP in elementary schools. To investigate factors that affect elementary school teachers' decisions to use 3D printing in teaching, this study uses a mixed methods research approach combining binary logistic regression with a qualitative thematic analysis approach. Both approaches assembled predictive constructs from a range of theories on (1) technology acceptance and (2) intentions to continue or abandon 3DMP use. Using a sample of 225 elementary teachers from Montenegro, this study empirically concluded that intentions to discontinue 3DMP was slightly more strongly correlated with the predictors (i.e., performance expectancy, effort expectancy, perceived pedagogical impact, personal innovativeness, management support, user interface quality, technology compatibility, social influence, student expectations) than was intentions to continue using 3DMP. Performance expectancy was a significant determinant of teachers’ continued use of a 3DMP approach. The remaining seven factors (constructs) were found to be insignificant predictors. Perceived pedagogical impact and technology compatibility were significantly associated with teachers' decisions to discontinue using 3DMP. Our results also suggest that the time required to use 3DMP during instruction, the impact of 3DMP on the implementation of curriculum activities, and the availability of 3D printers are all relevant factors that influence teachers’' decision to use or abandon 3DMP.
Keywords: elementary school, binary logistic regression, continuance intentions, thematic analysis approach, 3D modelling and printing
Published in DKUM: 26.03.2024; Views: 268; Downloads: 205
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5. Systemic logistics providersMimo Drašković, 2016, independent scientific component part or a chapter in a monograph Abstract: The functioning of a port and shipping system must be perfect in order to provide a competitive advantage and stable position in maritime market. The importance of logistics in business success of port and shipping organizations in contemporary conditions has become crucial. Due to that fact, more and more efforts are put in the designing of integral logistics systems. Thanks to a complex, systemic and networking approach, logistics today is improving the speed and efficiency of operations and significantly influences cost reduction and therewith fulfills one of the basic strategic functions, anticipating necessary key competences of the firm. It is a resource framework for the overcoming of strategic limitations and a method for the enhancement of the competitive position and all marketing and management functions. In addition to that, the integration of partners requires, by rule, a consistent restructuring of the total chain dedicated to the creation of added value, i.e. reengineering of logistics and production business processes. Flexible and small structural units are created, cooperating among each other in a decentralized manner, retaining their key competences and strategic significance for the integral network dominated by a single leading firm as a center of the system, i.e. focus of the supply chain. The paper analyzes the formation of new logistics and marketing paradigm of the beginning of the new century and millennium, anticipating the overcoming of the traditional 3PL three-party logistics concept and formation of contemporary 4PL concept.
Keywords: logistics, ports, logistic services, integral logistics systems, third party logistics, 3PL, fourth party logistics, 4PL, outsourcing
Published in DKUM: 09.05.2018; Views: 1350; Downloads: 123
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6. Multiphase approach to developing model of logistics for coastal tourist destinationsSanja Bauk, Željko Ivanović, 2016, independent scientific component part or a chapter in a monograph Abstract: The process of urbanization of coastal tourist destinations (CTDs) is taking place at high speed and at the same time creating a lot of complex problems. The positive trend of urbanization has resulted in increased volume of freight transport which leads to burdening the traffic network, time losses and causes traffic congestion problems on the streets with increased environmental pollution due to emissions, noise and vibration. These findings brought to some research being started on the EU level, aiming to develop new logistic solutions, so these areas could be developed on a sustainable basis. With this in mind, the paper proposes a method of developing a novel model of logistics (MoL) for CTDs through several stages. The point of proposed MoL lies in achieving optimal connectivity of transportation, warehousing and physical distribution of goods, and making it a single functional model, so as to allow simultaneous optimization of logistic processes in a CTD, and to incorporate logistics in tourist offer.
Keywords: coastal tourist destinations, urbanization, traffic network, sustainable logistic solutions, model of logistics, optimization
Published in DKUM: 09.05.2018; Views: 1292; Downloads: 457
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7. Comprehensible predictive modeling using regularized logistic regression and comorbidity based featuresGregor Štiglic, Petra Povalej Bržan, Nino Fijačko, Fei Wang, Alexandros Kalousis, Boris Delibašić, Zoran Obradović, 2015, original scientific article Abstract: Different studies have demonstrated the importance of comorbidities to better understand the origin and evolution of medical complications. This study focuses on improvement of the predictive model interpretability based on simple logical features representing comorbidities. We use group lasso based feature interaction discovery followed by a post-processing step, where simple logic terms are added. In the final step, we reduce the feature set by applying lasso logistic regression to obtain a compact set of non-zero coefficients that represent a more comprehensible predictive model. The effectiveness of the proposed approach was demonstrated on a pediatric hospital discharge dataset that was used to build a readmission risk estimation model. The evaluation of the proposed method demonstrates a reduction of the initial set of features in a regression model by 72%, with a slight improvement in the Area Under the ROC Curve metric from 0.763 (95% CI: 0.755%0.771) to 0.769 (95% CI: 0.761%0.777). Additionally, our results show improvement in comprehensibility of the final predictive model using simple comorbidity based terms for logistic regression.
Keywords: predictive models, logistic regression, readmission classification, comorbidities
Published in DKUM: 19.06.2017; Views: 1773; Downloads: 423
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8. The impact of selected individual and external factors on the occurrence of severe injuries : case study of SloveniaPolona Tominc, Urban Šebjan, 2015, original scientific article Abstract: The purpose of this paper is to contribute to the understanding of the importance of different determinants and their impact on the severity of injuries of individuals in road traffic accidents, so that measures that are supposed to prevent or reduce severe injury consequences can be developed. In this paper three research models have been built. Model I was built to study the impact of demographic factors (gender and age) on the individual’s likelihood to wear a seat-belt while Model II to study the impact of demographic factors (gender and age) and the impact of wearing a seat belt on the likelihood that fatal injuries of individuals in road traffic accidents occur. Model III was formed to study the impact of several environmental factors on the likelihood that the accident involves severe or fatal injuries of road traffic accident participants. Altogether our study revealed that middle-aged individuals (over 25 years and up to 65 years old) are less likely to wear a seatbelt and at the same time more likely to suffer fatal injuries in road traffic accidents. This is the result that implies that the targeted policy measures to the population between 25 and 65 years of age are needed to reduce the fatal injuries occurrence in Slovenia.
Keywords: road traffic accidents, seat belt, behavioural determinants, binomial logistic regression
Published in DKUM: 06.06.2017; Views: 1471; Downloads: 231
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9. Outsourcing of logistics activities in manufacturing industryAnton Ogorelc, Klavdij Logožar, 2001, original scientific article Abstract: The external supply of logistics services is part of a trend toward outsourcing non-core logistics activities. The scope of third-party logistics may range from a relatively limited combination of activities (e.g. transportation and warehousing) to a comprehensive set of logistics services. The authors first discuss the characteristics of business logistics in manufactoring industry, to be taken into account in logistics outsourcing. They particularly point out the motivations for logistics outsourcing, the possibilities of outsourcing, as well as supplier selection. Finally they analyze the outsourcing in the reverse logistics.
Keywords: outsourcing, logistic services, business logistics, supplier selection, reverse logistics
Published in DKUM: 05.06.2017; Views: 1206; Downloads: 265
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10. Multicriteria optimisation in logistics forwarder activitiesTanja Poletan, Alen Jugović, Ratko Zelenika, 2007, original scientific article Abstract: Logistics forwarder, as organizer and planner of coordination and integration of all the transport and logistics chains elements, uses adequate ways and methods in the process of planning and decision-making. One of these methods analysed in this paper, which could be used in optimisation of transport and logistics processes and activities of logistics forwarder, is the multicriteria optimisation method. Using that method, in this paper is suggested model of multicriteria optimisation of logistics forwarder activities. The suggested model of optimisation is justified in keeping with method principles of multicriteria optimization, which is included in operation research methods and it represents the process of multicriteria optimization of variants. Among many different processes of multicriteria optimization, PROMETHEE (Preference Ranking OrganizationMethod for Enrichment Evaluations) and Promcalc& Gaia V. 3.2., computer program of multicriteria programming, which is based on the mentioned process, were used.
Keywords: traffic, transport, forwarding, logistic chain, planning, optimisation, PROMETHEE
Published in DKUM: 05.06.2017; Views: 1169; Downloads: 217
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