Iskanje po katalogu digitalne knjižnice

Opis: The aim of the study was to examine the association between cardiorespiratory and metabolic parameters and match running performance (MRP) in highly trained football players. The sample of participants consisted of 41 national-level football players (aged 23.20 ± 3.40 years, body height 182.00 ± 5.15 cm, and body mass 76.86 ± 6.06 kg) from the Serbian Super league. For the purposes of this research, the following measurements were applied. A maximal multistage progressive treadmill test, with a direct measurement of maximal oxygen consumption (VO2max) (using Fitmate MED, Cosmed, Rome, Italy) was conducted, alongside continuous heart rate monitoring. Capillary blood samples were taken from the hyperemic area using specific test strips, and, after sample collection, lactate concentration was immediately determined using a lactate analyzer. MRP variables were analyzed according to the BioIRC model of motion structure analysis, based on existing standards for profiling movement intensity. The results of multiple regression analysis indicated an association between cardiac parameters and total distance (R2 = 54.3%, p = 0.000), high-speed running (R2 = 46.4%, p = 0.000), and jogging (R2 = 33.6%, p = 0.004). Regression analysis revealed an association between cardiorespiratory parameters and total distance (R2 = 24.8%, p = 0.014), and high-speed running (R2 = 20%, p = 0.039). Meanwhile, no association was found between lactate concentration and running performance. The explanation for these regression analysis results is based on the observation that functional abilities represent significant potential for expressing movement performance, a crucial condition for success in football.
Ključne besede: football players, physical performance, cardiovascular endurance, lactate concentration, maximal heart rate, professional soccer players, running performance analysis, VO2max
Objavljeno v DKUM: 01.07.2024; Ogledov: 104; Prenosov: 5
Celotno besedilo (1,74 MB)
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Opis: Robotic bin-picking is increasingly important in the order-picking process in intralogistics. However, many aspects of the robotic bin-picking process (object detection, grasping, manipulation) still require the research community's attention. Established methods are used to test robotic grippers, enabling comparability of the research community's results. This study presents a modified YCB Robotic Gripper Assessment Protocol that was used to evaluate the performance of four robotic grippers (twofingered, vacuum, gecko, and soft gripper). During the testing, 45 objects from the modified YCB Object and Model Set from the packaging categories, tools, small objects, spherical objects, and deformable objects were grasped and manipulated. The results of the robotic gripper evaluation show that while some robotic grippers performed substantially well, there is an expressive grasp success variation over diverse objects. The results indicate that selecting the object grasp point next to selecting the most suitable robotic gripper is critical in successful object grasping. Therefore, we propose grasp point determination using mechanical software simulation with a model of a two-fingered gripper in an ADAMS/MATLAB cosimulation. Performing software simulations for this task can save time and give comparable results to real-world experiments.
Ključne besede: intralogistics, robotic bin-picking, YCB protocol, robotic gripper evaluation, mechanical software simulations, performance analysis
Objavljeno v DKUM: 21.03.2024; Ogledov: 298; Prenosov: 11
Celotno besedilo (773,38 KB)
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Opis: Warehouses and distribution centres are based on integrated material handling solutions. Most of the research papers in intralogistics are only concerned with one system to analyse and optimise the addressed system's performance, such as maximum throughput performance, minimum total cost, maximum energy efficiency, etc. This paper presents a concept to justify the proposed VLM and SBS/RS integrated system and a binary integer programming (BIP) model that minimises totes exchange between the two storage systems. The results show that the minimal number of exchanges between VLM and SBS/RS was achieved in a case study with a longer order list (T = 1600) and a highly dependent SKU's Pareto relationship (20-50).
Ključne besede: automated warehousing, intralogistics, VLM, SBS, RS, integrated systemoptimisation, performance analysis
Objavljeno v DKUM: 02.08.2023; Ogledov: 390; Prenosov: 46
Celotno besedilo (743,43 KB)
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Opis: This Doctoral Thesis deals with the mechanisms for cross-border interchange and activation of the regulating reserves (RRs), i.e., Imbalance Netting Process (INP) and Cross-Border Activation of the RRs (CBRR), between participating Control Areas (CAs), to reduce the costs of balancing energy. The main objective of INP is to interchange the RRs between participating CAs with opposite signs of interchange power variation. In comparison, the main objective of CBRR is to activate the RRs in participating CAs with the same signs of interchange power variation. Both the INP and CBRR aim to release the RRs and reduce balancing energy as part of the power system's safe operation. The Thesis's main objective is to analyze the impact of the mechanisms for cross-border interchange and activation of the RRs on mutual oscillations of participating CAs and stability for small disturbances. The Thesis's secondary objective is to analyze the impact of the INP and CBRR on frequency quality, on the provision of Load-Frequency Control (LFC), on balancing energy and unintended exchange of energies between participating CAs. Frequency quality in Continental Europe (CE) has been declining in recent years, so it is important that the mechanisms for cross-border interchange and activation of the RRs do not further impair its quality. Both the classic INP and CBRR include a frequency-dependent contribution and, therefore, inherently affect the frequency response of the participating CAs, which is not discussed in the literature. Thus, the impact of the classic INP and CBRR on frequency quality and the provision of LFC is thoroughly evaluated with dynamic simulations of a three-CA test system and eigenvalue analysis of a two-CA system. It is demonstrated that both the classic INP and CBRR reduce the damping of the entire power system. Therefore, a modified implementation of the classic INP and CBRR is presented, and improved INP and CBRR are proposed, which have no impact on the mutual oscillations of participating CAs and stability for small disturbances. Furthermore, the dynamic simulations results confirm that the frequency quality can be improved by the classic INP and CBRR, although there are also cases where it can deteriorate. However, the improved INP and CBRR generally improve the frequency quality in all cases. The improved INP and CBRR also enhance the provision of LFC compared to the classic INP and CBRR. Moreover, the improved INP and CBRR reduce the unintended exchange of energies, thus increasing the economic effects of the INP's and CBRR's activation. The improved INP increases energy exchange, therefore positive economic benefits can be expected in comparison to the system with the classic INP. However, the improved CBRR reduces energy exchange, therefore positive economic benefits can be expected in comparison to the system with the classic CBRR, since energy exchange is paid by CA via bidding process.
Ključne besede: load-frequency control, imbalance netting, cross-border activation, balancing energy, regulating reserves, eigenvalue analysis, performance indicators, area control error, rate of change of frequency, control area
Objavljeno v DKUM: 09.03.2023; Ogledov: 594; Prenosov: 100
Celotno besedilo (14,64 MB)

Opis: The increasing number of network-shaped domains calls for the use of graph database technology, where there are continuous efforts to develop mechanisms to address domain challenges. Relationships as 'first-class citizens' in graph databases can play an important role in studying the structural and behavioural characteristics of the domain. In this dissertation, we focus on studying the cardinality constraints mechanism, which also exploits the edges of the underlying property graph. The results of our literature review indicate an obvious research gap when it comes to concepts and approaches for specifying and representing complex cardinality constraints for graph databases validated in practice. To address this gap, we present a novel and comprehensive approach called the k-vertex cardinality constraints model for enforcing higher-order cardinality constraints rules on edges, which capture domain-related business rules of varying complexity. In our formal k-vertex cardinality constraint concept definition, we go beyond simple patterns formed between two nodes and employ more complex structures such as hypernodes, which consist of nodes connected by edges. We formally introduce the concept of k-vertex cardinality constraints and their properties as well as the property graph-based model used for their representation. Our k-vertex model includes the k-vertex cardinality constraint specification by following a pre-defined syntax followed by a visual representation through a property graph-based data model and a set of algorithms for the implementation of basic operations relevant for working with k-vertex cardinality constraints. In the practical part of the dissertation, we evaluate the applicability of the k-vertex model on use cases by carrying two separate case studies where we present how the model can be implemented on fraud detection and data classification use cases. We build a set of relevant k-vertex cardinality constraints based on real data and explain how each step of our approach is to be done. The results obtained from the case studies prove that the k-vertex model is entirely suitable to represent complex business rules as cardinality constraints and can be used to enforce these cardinality constraints in real-world business scenarios. Next, we analyze the performance efficiency of our model on inserting new edges into graph databases with varying number of edges and outgoing node degree and compare it against the case when there is no cardinality constraints checking. The results of the statistical analysis confirm a stable performance of the k-vertex model on varying datasets when compared against a case with no cardinality constraints checking. The k-vertex model shows no significant performance effect on property graphs with varying complexity and it is able to serve as a cardinality constraints enforcement mechanism without large effects on the database performance.
Ključne besede: Graph database, K-vertex cardinality constraint, Cardinality, Business rule, Property graph data model, Property graph schema, Hypernode, Performance analysis, Fraud detection, Data classification
Objavljeno v DKUM: 10.08.2022; Ogledov: 771; Prenosov: 90
Celotno besedilo (3,43 MB)