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Preliminary project of heating caves for slabs
No full textJeklene slabe moramo pred procesom vročega valjanja ogreti v potisni peči na temperaturo preoblikovanja, kar je drag in energetsko potraten proces.
Z idejo, da bi privarčevali z zemeljskim plinom ter naredili vročo valjarno bolj učinkovito, bomo zasnovali ogrevalne jame, kjer bi slabe ogreli za približno 100 °C s pomočjo odpadnih dimnih plinov iz potisne peči in lastnih gorilnikov, kar bi občutno zmanjšalo porabo zemeljskega plina.
V okviru dela bomo izbrali gradnike jam ter gradnike cevovoda. Izračunali bomo izgube toplote skozi stene in pokrove jam, izgube toplote dimnih plinov v cevovodu ter porabo zemeljskega plina, ki bi ohranjal zadostno temperaturo v jamah ter obenem istočasno ogreval slabe. Določili bomo potreben čas za ogrevanje slabov v jamah ter dimenzionirali dimnik za odvod dimnih plinov.
Na podlagi izvedenih toplotnotehničnih izračunov bomo ovrednotili porabo zemeljskega plina glede na idejni projekt in jo primerjali s sedanjo porabo.Before the hot rolling process, the steel slabs must be heated in a pressure furnace to the transformation temperature, which is an expensive and energy consuming process.
With the idea of saving on natural gas and making the hot rolling mill more efficient, we have designed heating pits in which the slabs would be heated with natural gases from the pusher furnace and own burners by about 100 °C, which would significantly reduce natural gas consumption.
As part of the work, we selected the building elements of the caves and the building elements of the pipeline. We calculated heat losses through the walls and covers of the caves, heat losses of the flue gases in the pipeline and the consumption of natural gas, which would maintain a sufficient temperature in the caves and at the same time heat the slabs. We determined the time required for heating the slabs in the pits and dimensioned the flue for natural gas discharge.
Based on thermo-technical calculations, we will evaluate the consumption of natural gas according to preliminary project and compare it with current
Personalization of SAM cards in an HSM key ceremony on a use-case
Get PDFV diplomskem delu je obravnavano področje varnostnih sistemov za pametne kartice v javnem potniškem prometu. Predstavljena sta delovanje in koristna uporaba strojnih varnostnih modulov ter modulov za varen dostop. Po predstavitvi naprav so opisani tudi varnostni standardi ter komunikacijski protokoli pametnih kartic. Rezultat diplomskega dela je namizna aplikacija, Personalizator, s pomočjo katere je ponazorjen proces ceremonije ključev strojnega varnostnega modula. Prav tako je z uporabo izdelanega grafičnega vmesnika prikazana personalizacija modulov za varen dostop. Diplomsko delo se lahko uporabi kot primer ceremonije ključev in personalizacije modulov za varen dostop.The thesis deals with the field of security systems for smart cards in public passenger transport. The purpose is to present the operation and beneficial use of hardware security modules and secure access modules. After the presentation of the devices, the security standards and smart card communication protocols are also described. The result of this thesis is a desktop application named Personalizator, which helps to illustrate the hardware security module key ceremony procedure. Using the same graphical interface, the personalization of secure access modules was also achieved. The thesis can be used as an example of key ceremony and personalization of secure access module
Prompt injection attacks on large language models
Get PDFV magistrskem delu raziskujemo vlogo velikih jezikovnih modelov v vzponu generativne umetne inteligence. Predstavimo osnovne koncepte, kot so transformerji, žetoni in vektorske reprezentacije, ter opisujemo ključne prednosti, slabosti in izzive z generativnimi modeli. Posebno pozornost namenjamo izzivom varnosti, kot so pozivni injekcijski napadi. Podrobno analiziramo delovanje teh napadov, njihove vrste in predstavimo možne pristope za obrambo pred njimi. V okviru eksperimenta prikazujemo izdelavo spletne ankete, ki implementira različne jezikovne modele. S pomočjo pridobljenih podatkov iz ankete nato analiziramo občutljivost posameznih modelov na različne intenzitete injekcijskih napadov ter preučujemo njihove vplive na uporabniške dimenzije, kot so uporabnost, točnost, razumljivost in relevantnost. Na koncu ugotavljamo, kateri modeli se najbolje odzivajo na napade in predstavljajo najvarnejšo uporabo.In the master\u27s thesis, we explore the role of large language models in the rise of generative artificial intelligence. We present fundamental concepts such as transformers, tokens, and vector representations, and describe the key advantages, disadvantages, and challenges of generative models. Special attention is given to security challenges, such as prompt injection attacks. We analyze the functioning of these attacks in detail, their types, and propose possible defense approaches. As part of the experiment, we develop an online survey application that implements various language models. Using the data collected from the survey, we analyze the sensitivity of individual models to different intensities of injection attacks and examine their impacts on user dimensions such as usability, accuracy, understandability, and relevance. Finally, we identify which models respond best to the attacks and represent the most secure usage
Optimisation of burning in pusher type furnace with oxygen enriched air
No full textJeklene slabe moramo pred procesom vročega valjanja ogreti v potisni peči na temperaturo preoblikovanja, kar je drag in energetsko potraten proces.
Potisna peč v naši vroči valjarni predstavlja ozko grlo, zato smo z idejo, da bi povečali produktivnost peči, naredili model na osnovi računalniške dinamike tekočin (angleško computational fluid dynamics ali na kratko CFD), s katerim smo izračunali parametre, ki so za nas ključnega pomena, pri tem pa bi spreminjali vrsto goriva, ter delež kisika v zraku. Ti parametri so: temperatura plamena, emisije CO2, NOx ter delež saj.
V magistrskem delu so bile narejene tri simulacije za vsako vrsto goriva. Kot prvo gorivo smo vzeli zemeljski plin, naš trenuten energent v potisni peči. Kot potencialno substitucijsko gorivo, smo vzeli propan, namreč sta cena in dobava zemeljskega plina v trenutni geopolitični situaciji vprašljiva. Kot drugo substitucijsko gorivo, pa smo vzeli vodik, namreč vodik predstavlja zeleno gorivo prihodnosti. Drug parameter, ki smo ga pa spreminjali, pa je bil delež kisika v zgorevalnem zraku. Prva prevzeta vrednost je bila 21%, torej atmosferska vrednost, druga prevzeta vrednost je bila 23% in
tretja 25%.
Iz rezultatov simulacij, smo glede na temperaturo plamena, preko toplotnotehničnih izračunov določili novo zmogljivost peči. Preko preračunane zmogljivosti peči, pa smo lahko tudi vrednotili emisije CO2, NOx in delež saj na tono. Nato smo naredili primerjavo emisij glede na sedanjo stanje in ocenili, ali je zgorevanje s povišanim deležem kisika v zraku ekološki proces.
Za konec smo pa preko cene jekla na trgu, ter tržne cene tehnično čistega kisika naredili finančno bilanco, ali je zgorevanje s povišanim deležem kisika v zraku, tudi ekonomično rentabilen proces.We need to preheat the steel slabs before the hot rolling process in the pusher type furnace to the temperature suitable for hot rolling, which is an expensive and energy consuming process. The pusher type furnace in our hot rolling mill represents a bottleneck, so with the idea of increasing furnace productivity, we have created a model based on computational fluid dynamics (CFD), with which we have calculated parameters crucial to us, while varying the type of fuel and the oxygen content in the air. These parameters include flame temperature, CO2 emissions, NOx emissions and soot content.
In the master’s thesis three simulations were performed for each type of fuel. Firstly we used natural gas as the fuel, which is also our current energy source in the pusher type furnace. As a potential substitute, we have considered propane, as the price and supply of natural gas is questionable in current geopolitical situation. As second substitute fuel, we chose hydrogen, as hydrogen represents the green fuel of the future. The other parameter which we were varying was the oxygen content in the combustion air. First assumed value was 21 %, which is atmospheric value. Second assumed value was 23 % and the third was 25 %.
From the simulation results, we determined the new furnace capacity based on flame temperature through thermotehnical calculations. Using the calculated furnace capacity, we could also evaluate CO2 emissions, NOx emissions and soot content per ton. Then we compared emissions with the current state and assessed whether combustion with an increased oxygen content in the air is an environmentally friendly process.
Finally, we conducted a financial evaluation by comparing the market price of still and the market price of technically pure oxygen to determine whether combustion with an increased oxygen content in the air is also economically viable
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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