1. Analysing picking errors in vision picking systemsEla Vidovič, Brigita Gajšek, 2020, original scientific article Abstract: Vision picking empowers users with access to real-time digital order information, while freeing them from handheld radio frequency devices. The smart glasses, as an example of vision picking enabler, provide visual and voice cues to guide order pickers. The glasses mostly also have installed navigation features that can sense the order picker's position in the warehouse. This paper explores picking errors in vision systems with literature review and experimental work in laboratory environment. The results show the effectiveness of applying vision picking systems for the purposes of active error prevention, when they are compared to established methods, such as paper-picking and using cart mounted displays. A serious competitor to vision picking systems are pick-to-light systems. The strong advantage of vision picking system is that most of the errors are detected early in the process and not at the customer's site. The cost of fixing the error is thus minimal. Most errors consequently directly influence order picker's productivity in negative sense. Nonetheless, the distinctive feature of the system is extremely efficient error detection. Keywords: order picking, storage operations, warehousing, smart glasses, error prevention, inventory management, intralogistics Published in DKUM: 22.08.2024; Views: 83; Downloads: 4 Full text (672,66 KB) This document has many files! More... |
2. On parsing programming languages with Turing-complete parserBoštjan Slivnik, Marjan Mernik, 2023, original scientific article Abstract: A new parsing method based on the semi-Thue system is described. Similar to, but with more efficient implementation than Markov normal algorithms, it can be used for parsing any recursively enumerable language. Despite its computational power, it is meant to be used primarily for parsing programming and domain-specific languages. It enables a straightforward simulation of a number of existing parsing algorithms based on context-free grammars. The list includes both top-down shift-produce methods (such as SLL and LL) and bottom-up shift-reduce methods (such as LALR and LR), as well as mixed top-down-and-bottom-up methods such as LLLR. To justify the use of the new parsing method, the paper provides numerous examples of how a parser can actually be made in practice. It is advised that the main part of the parser is based on some simple well-established approach, e.g., SLL(1), while syntactically more complicated phrases can be parsed by exploiting the full power of the new parser. These phrases may either be extensions to the original language or some embedded domain-specific language. In all such and similar cases, no part of the language is restricted to be context-free. In fact, context-sensitive languages can be handled quite efficiently. Keywords: Turing-complete parsing, context-sensitive, error recovery Published in DKUM: 14.02.2024; Views: 325; Downloads: 23 Full text (534,88 KB) This document has many files! More... |
3. Analysis and improvements of the mechanisms for cross-border interchange and activation of the regulating reserves : doctoral dissertationMarcel Topler, 2022, doctoral dissertation Abstract: 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. Keywords: 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 Published in DKUM: 09.03.2023; Views: 594; Downloads: 104 Full text (14,64 MB) |
4. The Influence of Styrian and Upper Carniola Dialects on the Pronunciation of English of Slovene StudentsDominika Podvratnik, 2018, master's thesis Abstract: The master’s thesis considers the influence of Styrian and Upper Carniola dialect on the pronunciation of English of Slovene students. Various factors influence the Slovene students’ pronunciation of English. The influence of mother tongue on the Slovene students’ pronunciation of English has been firmly established. However, it is only logical to think that dialect also has an important influence on the Slovene students’ pronunciation of English. The purpose of the research is to determine the influence of Styrian dialect and Upper Carniola dialect on the pronunciation of English of Slovene students. The master’s thesis strengthens the evidence for dialect influence, observes the extent of dialect influence in both dialect areas, determines in which area the dialect influence on the pronunciation of English is more visible and identifies the reasons for such influence. The research employs various research methods. Contrastive analysis is used to compare the sound systems of Upper Carniola and Styrian dialect with the sound system of British English. Based on the findings of the contrastive analysis words are chosen and organised in a test which is used for obtaining samples for analysis. Fieldwork is then carried out. Auditory analysis of samples includes listening to audio material and producing phonemic transcriptions, which concludes with statistical analysis of data. The results show that both Upper Carniola and Styrian dialect significantly influence the pronunciation of English of Slovene students. Dialect influence is slightly more prevalent in the Styrian dialect region, especially in the case of RP English /e/ and /ʊ/. Slovene students of English speak interlanguage and their interphonology rules mostly stem from English phonological rules. Keywords: Upper Carniola dialect, Styrian dialect, contrastive analysis, error analysis, interlanguage Published in DKUM: 23.10.2018; Views: 1431; Downloads: 147 Full text (1,06 MB) |
5. Medical error - should it be a criminal offence?Miha Šepec, 2018, original scientific article Abstract: Medicine is a risky profession where medical professionals have a duty to do anything in their power to help their patients. However, what if a doctor makes a grievous mistake that leads to the death but could have been avoided? Are moral responsibility and apology to patients´ family enough? Should we impose sanctions (civil or criminal) on the doctor who negligently caused the patients´ death? To answer this questions, we present arguments against criminalisation of medical error, where the strongest arguments are uncertainty of medical standards, counterproductive criminalisation seen in defensive medicine, using criminal law as the last resort, and the argument of doctor´s immunity. On the other hand, arguments for criminalisation are obvious negligent treatment with serious consequences, general prevention of future negligent conduct, sanitation of a medical system gone wrong, and the argument of privileged criminal offence. Our conclusion is that criminal law repression of medical malpractice or medical error is justified, however only in the most obvious cases of undisputed negligence or carelessness of a doctor, where his inappropriate conduct has led to a serious deterioration of health of a patient, which could have easily been avoided, if a doctor respected the practice and rules of medical science and profession. Keywords: medical error, criminal law, criminal offence, medical malpractice, doctor, medical professional, negligent treatment Published in DKUM: 09.10.2018; Views: 49056; Downloads: 259 Full text (589,77 KB) This document has many files! More... |
6. Optimized PID position control of a nonlinear system based on correlating the velocity with position errorNenad Muškinja, Matej Rižnar, 2015, original scientific article Abstract: We examined a design approach for a PID controller for a nonlinear ball and beam system. Main objective of our research was to establish a nonmodel-based control system, which would also not be dependent on a specific ball and beam hardware setup. The proposed PID controller setup is based on a cascaded configuration of an inner PID ball velocity control loop and an outer proportional ball position control loop. The effectiveness of the proposed controller setup was first presented in simulation environment in comparison to a hardware dependent PD cascaded controller, along with a more comprehensive study on possible design approach for optimal PID controller parameters in relation to main functionality of the controller setup. Experimental real-time control results were then obtained on a laboratory setup of the ball and beam system on which PD cascaded controller could not be applied without parallel system model processing. Keywords: position control, nonlinear system, position error Published in DKUM: 15.06.2017; Views: 1171; Downloads: 441 Full text (3,23 MB) This document has many files! More... |
7. Reduction of the mean hedging transaction costsMiklavž Mastinšek, 2015, original scientific article Abstract: Transaction costs of derivative hedging appear in financial markets. This paper considers the problem of delta hedging and the reduction of expected proportional transaction costs. In the literature the expected approximate proportional transaction costs are customarily estimated by the gamma term, usually the largest term of the associated series expansion. However, when options are to expire in a month or few weeks, other terms may become even larger so that more precise estimates are needed. In this paper, different higher-order estimates of proportional transaction costs are analyzed. The problem of the reduction of expected transaction costs is considered. As a result, a suitably adjusted delta is given, for which the expected approximate proportional transaction costs can be reduced. The order of the mean and the variance of the hedging error can be preserved. Several examples are provided. Keywords: derivatives, delta hedging, transaction costs, hedging error Published in DKUM: 03.04.2017; Views: 1276; Downloads: 184 Full text (662,21 KB) This document has many files! More... |
8. ERROR PROBABILITY MODEL FOR IEEE 802.15.4 WIRELESS TRANSMISSION WITH CO-CHANNEL INTERFERENCE AND BACKGROUND NOISEUroš Pešović, 2016, doctoral dissertation Abstract: Data transmission sent through wireless channel is usually affected by background noise, multipath fading and interference which cause data errors. Influence of such disturbances is the most commonly expressed in a form of error probability statistics. Effects of these disturbances on IEEE 802.15.4 wireless transmissions are previously studied, except influence of co-channel interference (CCI) which originates from collision between IEEE 802.15.4 devices which perform simultaneous radio transmission. Our thesis puts forward the assumption that it is possible to derive more accurate analytical error probability model for higher data level error probability parameters without the idealization of PN spreading sequences. Additionally, thesis is that is possible to derive an accurate analytical error probability model in the case of CCI influenced by background noise by consideration of constellation diagram. IEEE 802.15.4 standard uses CSMA/CA (Carrier Sense Multiple Access with Collision Detection) channel access mechanism to prevent collisions between devices, but this mechanism doesn't provide protection from hidden node problem which is primary source of co-channel interference. Using Monte Carlo simulations we determined frequency of hidden node collisions, which shown that co-channel interference frequently occur in parts of the network with high traffic load. Some prior works in this field tend to idealize these non-ideal spreading sequences in order to simplify calculations for error probability parameters. Our doctor thesis presents analytical model of data level error probability parameters (symbol, bit and packet) for IEEE 802.15.4, which uses original non-ideal spreading sequences without their idealization. Proposed error probability model consists of mutually dependent chip, symbol, bit and packet error probability models. Derived error probability models are linked together, so each of error probability parameters can be determined using error probability parameter from the previous stage. Error probability model for IEEE 802.15.4 wireless communication could be used in network simulation tools in order to accurately simulate energy efficient medium access protocols in realistic scenarios. Presented theoretical results are tested by independent numerical simulation of IEEE 802.15.4 transmission according to Monte Carlo method. Simulation results shows that derived models for error probability parameters were matched by two simulation scenarios in background noise, for multipath fading and co-channel interface, respectively Furthermore, the accuracy of derived mathematical models was tested in real-world experiment using IEEE 802.15.4 compliant wireless transceivers for creating co-channel interference. Packets were received by software defined radio platform, which enabled realization of coherent receiver in which all error probability statistics could be collected. The results of the experiment show consistency with proposed analytical error probability models, but some deviations are caused by poor preamble synchronization under low SNR (Signal to Noise Ratio) value. The thesis was proved with Monte Carlo simulations of the physical level of the IEEE 802.15.4 communication and experimental measurements on a real physical communication system. Keywords: IEEE 802.15.4 standard, error probability model, co-channel interference, Rician fading channel, additive white Gaussian noise, wireless transmission, wireless sensor networks, numerical simulations, software defined radio Published in DKUM: 14.10.2016; Views: 2502; Downloads: 140 Full text (8,20 MB) |
9. Foreign students' speech in EnglandManca Potušek, 2016, undergraduate thesis Abstract: The diploma thesis focuses on the influence of the French, Italian and Spanish language on the Standard Southern British English pronunciation. The research is based on the recordings of 10 French, 9 Italian and 9 Spanish students who spent half a year in England as Erasmus exchange students.
The theoretical part starts with an introductory chapter describing a short history of all four languages, as well as the position of the English language in the world and in the European Union. East Midlands English and Standard Southern British English are then presented with their phonological characteristics. Furthermore, the vowel systems of French, Italian and Spanish language are presented together with the most common errors the speakers of these languages encounter when pronouncing English vowels. In the following chapter the term “interlanguage” and research methods as Contrastive Analysis and Error Analysis are described. In the last segment of the theoretical part we are dealing with so-called formants which are frequencies that the vowels are made of and are essential for identification of a vowel.
In the empirical part, Error Analysis is used as a research method. The key part of the research is the analysis of the recordings of foreign students’ pronunciation of 11 SSBE vowels. The results of the research clearly prove a strong influence of the French, Italian, and Spanish accents on the pronunciation of SSBE vowels, as well as a great impact of General American. To analyse the data, the descriptive method was used.
The findings of the dissertation could be of help to other researchers or English teachers should they find themselves teaching in France, Italy or Spain. Keywords: Standard Southern British English, vowels, formants, foreign students, Error Analysis Published in DKUM: 08.09.2016; Views: 1601; Downloads: 90 Full text (1,98 MB) |
10. Perfect codes in direct products of cycles - a complete characterizationJanez Žerovnik, 2008, original scientific article Abstract: Let ▫$G = times^n_{i=1}C_{ell_i}$▫ be a direct product of cycles. It is known that for any ▫$r le 1$▫, and any ▫$n le 2▫$, each connected component of ▫$G$▫ contains a so-called canonical ▫$r$▫-perfect code provided that each ▫$ell_i$▫ is a multiple of ▫$r^n + (r+1)^n$▫. Here we prove that up to a reasonably defined equivalence, these are the only perfect codes that exist. Keywords: matematika, teorija grafov, korekcijske kode, direktni produkt grafov, popolne kode, cikli, mathematics, graph theory, error-correcting codes, direct product of graphs, perfect codes, cycles Published in DKUM: 10.07.2015; Views: 1886; Downloads: 92 Link to full text |