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We study algebraic systems M_Γ of free semigroup structure, where Γ is a well ordered finite alphabet, discovered in 1970s within the Theory of Electric Circuits by Miro Šare, and finding recent applications in Multivalued Logic, as well as in Computational Linguistics. We provide three simple axioms (reversion axiom (5) and two compression axioms (6) and (7)), which generate the corresponding equivalence relation between words. We also introduce a class of incompressible words, as well as the quotient Šare system \tilde M_Γ. The main result is contained in Theorem 16, announced by Šare without proof, which characterizes the equivalence of two words by means of Šare sums. The proof is constructive. We describe an algorithm for compression of words, study homomorphisms between quotient Šare systems for various alphabets Γ (Theorem 38), and introduce two natural Šare categories Ša(M) and Ša(\tilde M). Quotient Šare systems are regular semigroups, but not inverse semigroups.

Jezikoslovni povezani podatci (LLOD- http://linguistic-lod.org/llod-cloud) sumoderan način mrežnog objavljivanja lingvističkih podataka i mrežne obradbe prirodnoga jezika, utemeljenina nekoliko načela, od kojih su za jezikoslovce najvažniji sljedeći: a) podatci se mogu slobodno dohvaćati uz uobičajenaautorska prava (npr. uz Creative Commons licenses) ; b)dio su općeg, tj.javnog repozitorija, tj.koriste iste mrežne standarde (RDF, JSON-LD i sl.) pa se mogu s lakoćom povezivatis drugim podatcima ; c)sve se aktivnosti mogu pratiti preko običnog mrežnog preglednika.Povezani grafovi jezikoslovnih podataka sunajfleksibilnijiformat za interoperabilnost, jer se RDF modeli iz različitih jezikoslovnihresursa mogu s lakoćom integrirati.Povezanost s drugim izvorima otvara dodatnu semantiku, tj. pomaže korisnicima otkrivanje dodatnih izvora u globalnoj mreži. Razlog tomu je što su izvori na koji je povezan nekimodel na identičannačin povezani is drugim, a drugis trećim izvorima itd, koje korisnik u početku niti ne zna da postoje. Radi se ojezikoslovlnom podgrafuglobalnogmrežnogoblaka(LOD) s više od 90 milijardi trojaca(granapovezanih podataka ugrafu). Od travnja 2018 godine sintaksno-semantički okvir SSF postao je dio globalnog LLODa s preko 20.000 poveznica na BabelNet ontologiju i preko 67.000 poveznica na LexInfo. Mrežni podatci hrvatskih leksikona svakodjevno se s lakoćom upotpunjuju, i pritom odgovarajuće opisuju preko OWL, Lemon ili NIF modela. Međutim, nisu samo povezanosti riječi iz triju vrsta SSF rječnika (MSY/LEX/MWE) s drugim riječima globalnoga oblaka jedina vrijednost ovog rada. Posebna snaga leži u dohvatljivim semantičkim uzorcima, tzv. „sentic patterns' koji su zadnji iskorak u svijetu semantičke analize velikih ('big data') podataka, a koje SSF ima dobro razvijene u svojoj O-strukturi –uzorcima gramatičkih (WOS) i semantičkih (SOW) obilježja.Radi se, dakle, o kvalitetnom ulasku i instalaciji hrvatskogajezika među druge svjetske jezike, na mjestu koje mu već stoljećima pripada.

This paper based on M-theory wants to show the correlation of Cartesian product of elements of ordered set with a basic, multi-value logic. Using simple algorithms discovered by M. Sare in the natural laws of electrical networks, it is possible to construct logical tables, i.e. grids, for all logic functions of n variables.

In this paper we show several segments of program solutions which are a part of the Croatian Linguistic System (CLS) that is being developed in several ways and aims at achieving the final integration of all modules. Although the system aims at programmatically connecting all areas of linguistics (from phonetics to discourse), in the demonstration we will show only the segments that are related to general lexicon building (which includes a standard and terminological dictionary of the Croatian language) and will be connected with online repositories and encyclopedias. These program segments are searching for neologisms in documents (i.e. words that have not been marked in the general lexicon), generating grammatical forms of such words if they are changeable and saving them into a lexicon, adding semantic markups (like morphosyntactic) characteristics, and, finally, monitoring Croatian words in space and time.

In this paper we show several segments of program solutions which are a part of the Croatian linguistic system (CLS) that is being developed in several ways and aims at achieving the final integration of all modules. Although the system aims at programmatically connecting all areas of linguistics (from phonetics to discourse), in the demonstration we will show only the segments that are related to general lexicon building (which includes a standard and terminological dictionary of the Croatian language) and will be connected with online repositories and encyclopedias. These program segments are searching for neologisms in documents (i.e. words that have not been marked in the general lexicon), generating grammatical forms of such words if they are changeable and saving them into a lexicon, adding semantic markups (like morphosyntactic) characteristics, and, finally, monitoring Croatian words in space and time.

In this paper we describe an online application which connects various Croatian lexicographical sources (the standard dictionary, professional terminology, and encyclopedias) into a new network framework, which solves the problems of the currently available network solutions and offers new features. Although developed for the formation and processing of the professional terminology of technical sciences (primarily engineering), this framework is easily extensible to all other science areas (humanities, medicine, architecture, etc.). From a word formation standpoint, this framework provides an automatic generation of a temporary dictionary of a given text (entered or taken from the web), comparison of and updating a permanent dictionary with a temporary one (detection of neologisms), an automatic display (standard, professional and encyclopedic) of definitions of the words from the main dictionary or external (network) sources of a given text. From the point of view of processing, the framework enables a classic text analysis (frequency, concordances, statistics), converting the collected data (e.g. technical words) to the linked open data (LOD), and storing it into the Virtuoso triplestore repository. On this data, a variety of professional ontologies for viewing and searching can be developed.

U izlaganju će se prikazati mogućnosti istraživanja stare i rijetke građe u sklopu projekata unutar digitalne humanistike koji najčešće podrazumijevaju suradnju više istraživača pri istraživanju istog dokumenta, odnosno suradničko okruženje koje često uključuje istraživače koji su udaljeni i koji dolaze iz različitih disciplina, s različitim ekspertizama i područjima zanimanja, brigu o podacima znanstvenih istraživanja te kvantitativne metode, odnosno statističku analizu podataka te daljnje interpretacije dobivenih podataka. U skladu s takvim suvremenim zahtjevima na Fakultetu strojarstva i brodogradnje u Zagrebu izrađen je računalni program DocMark, koji se koristi za istraživanje dokumenata, i to označivanjem vizualnim oznakama koje se postavljaju na digitaliziranu sliku dokumenta, preciznim mjerenjem i kvantitativnom analizom postavljenih oznaka. U izlaganju će se prikazati program DocMark, pojasnit će se razlozi njegove izrade i mogućnosti koje ima trenutno, ali i koje je moguće dodati, u skladu sa zahtjevima novih istraživanja, odnosno u skladu s potrebama projekata vezanih uz digitalizaciju i istraživanje stare i rijetke građe koja se čuva u baštinskim ustanovama. DocMark koristi WebGL, JavaScript i PHP/MySQL tehnologiju, a korisniku programa omogućen je rad u jednom ili u više slojeva u kojima korisnik postavlja vizualne oznake, kojima je unaprijed pridruženo određeno svojstvo/kategorija, na željeno mjesto na dokumentu. Program obuhvaća i alat za precizno mjerenje te označivanje određenih područja dokumenta što je osobito važno za kodikološka istraživanja, a sve postavljene oznake, vrijednosti mjerenja i opisi se spremaju u bazu. Omogućeno je pretraživanje dokumenata prema svim označenim elementima, analiza, usporedba i pregledavanje dokumenata, označenih elemenata i bilježaka unesenih uz pojedine stranice ili cijeli dokument, te to da dokument označuje više udaljenih korisnika. U drugom će se dijelu izlaganja prikazati ilustrativni rezultati istraživanja srednjovjekovnih i ranonovovjekovnih rukopisa i stare tiskane građe te mogućnosti istraživanja odabranih kodikoloških, tipografskih, paleografskih (grafetičkih) i drugih osobitosti rukopisa i stare tiskane građe uz pomoć računalnog programa DocMark.

Croatian institutions are in a possession of a large corpus of digitalized cultural heritage, which is sometimes stored in archives and accessible only to professionals, and sometimes it is publically available on the Internet. The DocMark program was built with the aim of tag digitalized image documents so that those tags may be analyzed and/or compared in each document. After the DocMark was built, it took three years to build TEIMark – text marking program which recognizes typed, transcribed or automatically recognized texts. While in DocMark tagging is performed on the image document (in which material characteristics are interesting and reachable unlike the content), in TEIMark tagging is performed on the real text, and not its image. This enables research focused on the content of the document such as linguistic research (here we will give an example of metaphor tagging) and other content focused research.

Manuscripts are often fundamental sources for researchers in many disciplines, and nowadays this research is enhanced by new tools brought up by information technology. In this article, different methodologies of manuscript research in digital environment based on annotation are described. In the first part of the article, the annotation itself and the XML (eXtensible Markup Language) are explained. In the second part, different types of annotation methodologies are proposed for two types of researches, TEI and TEIMark that serve for encoding of transcribed versions of manuscripts and are proposed for researches based on a text, and DocMark that serves for encoding and analysing of digitised versions of manuscripts and is proposed for researches based on a text together with its physical context. Additionally, History Integrator software which places manuscripts into the time and space framework, with additional multimedia information is described.

In this work are compared performances of five different robot control algorithms. The following controllers under consideration are: PD controller, PID controller, analytical fuzzy controller, classical adaptive controller and adaptive controller based on neural network. The mentioned controllers are used to control two different robot configurations with two rotational degrees of freedom (in horizontal and vertical plane). The basic performances for control algorithms comparisons are: tracking error, rate of convergence, robustness on structural changes of control object, complexity of stability criterion and complexity of implementation.

Članak daje kratki pregled shema metapodataka bitnih za područje knjižničarstva. Opisan je RDF formalni model za razmjenu metapodtaka te je prikazan OpenURL standard za lakše identificiranje, pristup i nadziranje mrežnih izvora tehnologijom razmjene metapodataka kroz URL. Isti pridonose uvođenju reda na mreži i u informacijskom prostoru te omogućuju automatsko pronalaženje i upravljanje informacijama, što svakako treba biti predmet proučavanja suvremenog knjižničarstva i informacijskih znanosti. Autori navode PHP kod s OpenURL zadaćom te preporučuju implementaciju istog za mrežne publikacije s ciljem tvorbe COinS objekata te povezivanja informacijskih izvora na mreži.

DBpedia projekt načinjen je u svrhu ekstrakcije strukturiranih informacija iz Wikipedije s ciljem da ih se učini dostupnim na webu. Rezultat je DBpedia - baza znanja, koja opisuje veliki broj entiteta (osobe, mjesta, glazbene radove, filmove, organizacije). Za svaki entitet DBpedia definira jedinstveni identifikator. Sve veći broj ustanova, nakladnika i pojedinaca postavlja poveznice na nju, na razini podataka, te tako DBpedia postaje središte međusobnog povezivanja rastućeg weba podataka (engl. Web of data). Wikipedijini članci sastoje se od slobodnog teksta, ali također sadrže i strukturirane informacije u formi wiki oznaka (eng. wiki markup). Takve informacije uključuju npr. infookviri, kategorije, fotografije, geo-koordinate, poveznice na vanjske stranice, poveznice između različitih jezičnih izdanja Wikipedije. Rad će ukratko prikazati DBpedia ontologiju te će objasniti njezinu ulogu u ovom projektu. Cilj rada je prikazati uključivanje izdanja hrvatske Wikipedije u projekt DBpedia. Navedeno uključivanje izvršeno je putem ekstrakcije strukturiranih informacija iz infookvira hrvatske Wikipedije. U svrhu navedenog cilja prikazat će se primjeri izvršenog postupka pridruživanja pojedinog infookvira ontologijskoj klasi, kao i pridruživanja svojstava infookvira s ontologijskim svojstvima. Rezultat ovog postupka su strukturirane informacije u RDF obliku. Prikazat će se i ekstrakcija RDF trojaca iz nestrukturiranog teksta upotrebom alata za obradbu prirodnih jezika (NLTK) razvijenih upotrebom Python programa. Na koncu će se dati pregled dobivenih rezultata.

Zotero je program otvorenog koda unutar Mozzila WEB-preglednika namijenjen automatskom dohvaćanju, uređivanju i upravljanju bibliografskim bilješkama ; eksportiranju istih u razne formate i izradi bibliografije različitih stilova. Razvili su ga Center for History and New Media na George Mason University. Takvi programi za upravljanje bibliografskim bilješkama (reference managers) arhiviraju i organiziraju radove koje citira korisnik. (Muldrow, Yoder ; 2009) Namijenjeni su istraživačima, nastavnicima, studentima i knjižničarima za stvaranje osobnih baza podataka koje sadrže isključivo njima najvažnije bibliografske bilješke. Zotero promiče novi pristup u razvoju pomagala za upravljanje bibliografskim bilješkama. Za razliku od svojih prethodnika (EndNote, RefWorks, ProCite i sl.), koji predstavljaju samostalne aplikacije, Zotero je svoje mjesto našao upravo tamo gdje korisnici često borave – na mreži, tražeći informacije, pa je ugrađen u popularan WEB preglednik – Mozilla Firefox. Osim primjene uspješnih osobina svojih prethodnika, iskorištava i dostignuća modernih softvera i mrežnih aplikacija: iTunes-a i del.icio.us-a, osiguravajući interakciju, stavljanje oznaka i napredno pretraživanje. Jednako dobro funkcionira i offline, osim što tada, dakako, ne dohvaća online jedinice pohranjene u zbirkama. Članak opisuje njegove mogućnosti i kompatibilnost s određenim standardima, naglašavajući njegovu primjenljivost u knjižničarstvu. Detaljnija usporedba pojedinih programa za upravljanje bibliografskim bilješkama nije predmet ovog rada.

Scriptrunner web-sustav omogućuje korisniku da unutar svog XHTML ili PDF dokumenta (generiranog iz besplatnog LaTeX okoliša) poziva program pisan u bilo kojem programskom jeziku (npr. u Pythonu, Javi, C++, WR Mathematici i sl.), koji se izvodi na serveru i vraća rezultate u stranicu korisnika. Korisnik pritom može, ako je program tako napisan, zadavati (preko HTML ili PDF forme/obrasca) različite ulazne podatke koje program prihvaća, pa će prema njima dobiti i odgovarajuće (alfanumeričko i/ili grafičko) rješenje. Štoviše, korisnik može (na)pisati vlastiti programski kôd i izvršavati ga na daljinu, a da pritom na svom stroju nema nikakav potreban programski prevoditelj (compiler) ili interpreter. Posljedice su dalekosežne, jer web-podatak (uz sve postojeće DOM/XML objekte) postaje tako promjenljivi, te nadasve povezivi, programski kôd, čija kompleksnost može neograničeno rasti (za razliku od krutog tekstovnog označivanja/tagiranja). U ovom radu pokazana je njegova upotreba u on-line stvaranju digitalnih e-udžbenika, članaka ili prospekata koji uključuju rad s web-arhivima, knjižnicama i/ili muzejima, koristeći njihove resurse, pozivima preko programa pozivanih iz 'živog' PDF dokumenta. Tako svaki čitatelj može čitati ovu vrstu Web/PDF-dokumenta na svoj način, uz jedini uvjet - da je spojen na Internet.

U radu je prikazano istraživanje rukopisnih i tiskanih knjiga iz razdoblja hrvatskog srednjovjekovlja pisanih na trima jezicima i trima pismima. Svrha rada je prikazati mogućnosti istraživanja odabranih kodikoloških, tipografskih, bibliografskih i leksičkih osobitosti primjeraka, bilježenja podataka o stanju te onih važnih za povijest pojedinačnog primjerka te analiza i usporedba pojedinačnih primjeraka prema tim kriterijama. Označivanje i analiza digitaliziranog dokumenta ostvareno je računalnim programom DocMark koji koristi WebGL, JavaScript i PHP/MySQL tehnologiju pa se poziva preko interneta. Korisniku je omogućen rad na slici dokumenta, i to u jednom ili u više slojeva. U svakom sloju, nakon izbora oznaka, korisnik klikom miša na željeno mjesto postavlja vizualnu oznaku. Razlikuje se više vrsta oznaka kojima je unaprijed pridruženo određeno svojstvo/kategorija (analogno izboru neke TEI oznake). Omogućen je i alat za precizno mjerenje te označivanje određenih područja dokumenta. Sve oznake, mjerenja i opisi se spremaju u bazu i lako dohvaćaju. Također je omogućeno pretraživanje dokumenata prema svim označenim elementima, analiza, usporedbe i pregledavanje dokumenata, označenih elemenata i bilježaka unesenih uz pojedine stranice ili cijeli dokument. Program je mrežno dostupan pa je moguće da oznake na isti dokument postavlja više udaljenih korisnika. U radu su predložena i daljnja istraživanja uz korištenje iste metodologije.

This paper reports the design and control of a 50 kN hydraulic press which is made for experimental verification of control algorithms as well as for educational purposes. The press contains a servo-solenoid pressure control valve for regulating the pressure in the cylinder chamber and thus the force of hydraulic press. The system is equipped with a pressure sensor installed in the cylinder chamber for indirectly measuring the pressing force. At the considered press it is also possible to measure position of the upper plate by using a micro-pulse linear transducer. This created conditions for the realization of a position/force hybrid control algorithm. The control algorithms and monitoring process are implemented on a real-time hardware board. They are programmed in Matlab/Simulink environment using Real-Time Workshop tool for generating the C code and building an executive program. Based on the experimental results it can be concluded that electrically actuated control components supported by appropriate computer programs enable the realization of improved characteristics of systems required in modern industrial plants.

This paper focuses on the use of the techniques based on linear matrix inequalities for robust H_infinity position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro- hydraulic coefficients are taken into account. H_infinity controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of electro-hydraulic servo system.

The main principles for motion control in modern machinery design that use hydraulic energy are throttling principle by using constant displacement pump and proportional or servo valve in line with the actuator, and volumetric control principle by using constant-speed electric motor in combination with a variable displacement pump or variable-speed induction motor in combination with a constant displacement pump. By using a directional control valve in the hydraulic circuit for controlling the flow to and from the hydraulic actuator a constant quantity of oil is always required which leads to the oil being more heated and more electrically energy is consumed. Thus, regularly occur problems with heating oil and usually a separate heat exchanger is used in the hydraulic system. This conventional control principle is associated with significant loss of energy ; however a good dynamic behavior of the control system can be achieved. Increased use of volumetrically controlled hydraulic energy where speed of the induction motor is adjusted by the frequency converter in a closed loop control is motivated by its large range of the system overall efficiency and its favorable price, which is enabled by using modern microprocessor technology and digital control theory. In the case of frequency controlled drive only the amount of fluid required to achieve the desired speed has to be supplied, and this smaller flow of fluid means lower energy consumption, which makes an example of modern solution in electro-hydraulic technology application. The aim of this article is the comparison of these two control concepts on the example of hydraulic motor speed control. The actuator speed can be controlled both by using a servo valve and by controlling the speed of the induction motor and pump by means of the frequency converter and control computer with digital electronic card. The control strategies will be experimentally validated on a rotary hydraulic system, which is designed at our Laboratory. The controller is tuned according to damping optimum method in order to achieve precise speed control of the hydraulic motor. The control algorithms and monitoring process are implemented on a real-time hardware board that is programmed in Matlab/Simulink environment using Real-Time Workshop program. The experimental results show that the displacement-controlled system can produce satisfactory response characteristics and yield an effective trade-off between control performance and energy efficiency of the control system.

The article presents three experimental systems made for the purpose of conducting research in the field of proportional and servo hydraulics, as well as the purpose of training students. The first system is a module for controlling linear motion of hydraulic actuator. The control system consists of a main cylinder which is controlled by using a proportional directional control valve that can supply the cylinder with hydraulic fluid. Disturbance is generated by using a pressure control valve and a load cylinder, which produces a reaction force. Two cylinder rods are coupled by a steel joint. The second system is a module for the control of force, i.e. a hydraulic press where it is possible to regulate the force of compressing. To hold pressure in the cylinder’ s chamber and thereby the cylinder’ s force to the desired value, a pressure type servo valve is used. The third system is a module for controlling rotational motion of hydraulic actuator. In this system a hydraulic motor as a control object is used, where the disturbance is generated by using a hydraulic pump whose output pressure is adjusted using the proportional pressure valve. Motor and pump rods are tightly connected. The hydraulic motor speed can be controlled both by using a servo valve (throttling principle) and by controlling the speed of the induction motor and supply pump by means of the frequency converter and control computer with digital electronic card (volumetric control principle). All three systems also include measurement and control equipment for the realization of control algorithm. The experimental verifications are made using these three experimental systems – the module for linear motion control, the module for control of force and the module for rotational motion control that have been made at our Laboratory. The experimental results for controlling the position of hydraulic cylinder, for controlling the force of hydraulic press, as well as for controlling the speed rotation of hydraulic motor are displayed. The control algorithms and monitoring process are implemented on a real-time hardware board that is programmed in Matlab/Simulink environment using Real-Time Workshop program.

This paper deals with the position control of a hydraulic actuator regulated by a proportional directional control valve. The control algorithms based on the proportional-derivative controller have been applied to a specially designed two-channel electro-hydraulic servo system, which has the capacity to experimentally simulate common circumstances of a typical fluid power circuit. The first system includes the positioning hydraulic cylinder controlled using the proportional valve, a displacement measuring system and a control device in a closed-loop system. In order to add further realism in the control system a second double acting hydraulic cylinder is used to generate the disturbing load. The effectiveness of the proposed control algorithms is demonstrated for both moving directions as well as for both unloaded and loaded system. The results of the experimental testing have shown that for some industrial applications a relatively good motion control performances can be achieved using a proportional valve as a control component with a simple control algorithm, but for the case of changing operating conditions, some advanced control approaches should be used.

In this paper we have described one plug-in of educational Scriptrunner system, which through visual tool allows learning, training and testing of students, workers and employees over the Internet. Application is wide and verified: from factory halls and driving schools through students in classrooms and various psychological researches. Thanks to a good control (especially in terms of time) of video objects with supporting features (text, audio, video) this tool has been proven to be useful in studying and checking (workers prescreening). Since this plug-in is embedded in our Web collaboration system, it has all of the Scriptrunner’ s power possibilities. ‘ Visual aids’ plug-in has similar features of commercial Learning Management System, too.

The object of this poster presentation is to show a new approach to computer exercises in the course: Linear Programming. The exercises shall be organized in a computer lab for one group of students who will start the program within the Scriptrunner system. The program shall be performed over a WEB browser and student need no other program which might be installed on a lab's computer. A program has been developed for them there (in the same way as for any other types of math/computer exercises) and it shall set assignment(s) to students and shall require their solution and correct results. However, instead of a total program code which has to be supplied (written and executed) by a student, only a part of the program code shall appear, with certain parts missing. A student shall have to ll in the missing code part and start the execution. The screen area is divided into an input code - which is visible and shall be amended by additional data, and into an output code - in which after execution a solution appears. A student may solve the problem step-by-step, by the entry of the missing parts of the program code and watch whether he/she obtained the correct results. Only after he/she lls in correctly all invisible spaces by a missing program code he/she will get a con rmation and a grade for the successfully solved assignment. The Supervisor of the exercises shall be able to control any time over his web interface ; nally he will grade on-line all students' assignments. For those students that were not able to solve the task correctly, he will enable them to 'see the correct results'. For laboratory exercises in linear programming the simplex and interior-point method cases (author's diploma work) with the necessary programs written in Matlab were interpreted. (

The object of this poster presentation is to render an educational manual on numerical integration which is stored in a separately developed PDF format with interactive forms. The novelty consists in the following: a student reads the mathematical contents (author's diploma work) individual topics on numerical integration and studies the examples of every algorithm. If he/she is online, he/she is o ered the possibility to perform each and every pro- gram example (written in Python) over Internet. A special computer system Scriptrunner serves for this purpose ; however, the user/reader needs not to be familiar with the program. The program is executed by the Scriptrunner and results are returned to the sender. In this way, the new educational possibility is accomplished: every reader reads the manual in his own way, i.e. instead of only one example arbitrarily many examples are available, depending on the input data sent for the program. The reader of the PDF document needs not to have any program installed on his computer except the PDF viewer and an Internet browser. This manual includes algorithms and programs for Newton-Cotes formulas ; simple, composite and recursive trapezoidal rule ; Simpson's rules, Romberg in- tegration, Gaussian integration formulas (Gauss-Chebyshev, Gauss-Laguerre and Gauss-Hermite quadrature) etc. Likewise, many other manuals may be rendered available, too ; the manuals from all mathematical elds using com- puter and algorithms for them may be solved in any programming language. This novelty provides a new dimension for the future digital textbooks.

The main focus in this paper is on modeling and computer simulations of hydraulic systems for achieving a linear or rotary actuator motion, which are mostly used for high-power industrial applications. The hydraulic servo systems are very important systems for control applications because they take the advantages of both the large output power of traditional hydraulic systems and a high servo control response of electric systems. A nonlinear dynamic model for both translational and rotational motion of hydraulic actuator has been derived, which can be used in simulation studies of dynamic behavior of system and for advanced controller design. The hydraulic control system model has been derived as coupled sets of nonlinear algebraic and differential equations, which includes the main phenomena of physical system. This form of modeling equations has been resulted in a block-oriented system model. The simulation model includes the flow and force equations necessary to describe dynamic behavior of the control system and allows the prediction of performance of hydraulic system through computer simulation. A simulation model depicting the two control systems has been built, which may be used for an easy comparison of dynamical behavior of common hydraulic systems in industry. The model also contains several important dynamic characteristics those substantially influence the performance of the system within the operation range. Model development and preliminary experimental testing on laboratory setup are in progress.

"Educational WEB System" is a system made

The distance educational tools have been developing with the fact that the topics for simulations can demand special approach. The only thing required to use the full power of it is a Web browser which supports frames and JavaScript. Interface is straight-forward and simple, which facilitates interaction between a professor and student. Using teaching experience the simulation toolbox will offer easy learning of simulations with the approach by example. Two approaches of simulation learning are available: the first one per which a student has to write for the partly set assignment one part of the program code and the second one per which student analyzes and learns by modification of parameters (input data) the obtained simulation results.

Web Exams is a project which was created to make practice, knowledge checks and exams easier, faster and less expensive. The only thing required to use the full power of it is a Web browser which supports frames and JavaScript. Interface is straight-forward and simple, which facilitates interaction between a teacher and a student.

Proportional pressure regulators are usually used in different automation processes where continuous pressure or force control is required. They originated from the combination of an electro-pneumatic pilot valve, pressure regulator and pressure sensor for achieving an internal pressure feedback. These valves have practically linear pressure output regarding to an electrical signal from a control device. By controlling pressures in both cylinder chambers they can be used for direct force control of a pneumatic system. However, in this paper, also the position control of a pneumatic actuator using two proportional pressure regulators has been considered. A simplified dynamic model of the process has been derived, followed by a design of the PD controller for the system control. The control algorithms are experimentally verified on an industrial pneumatic cylinder controlled by two proportional pressure valves. The results demonstrate that the proportional pressure valves have a potential for successful implementation in hybrid force/position control tasks.

Scriptrunner is a program for remote execution of your programs written in various programming languages and mathematic tools and publishing of interactive documents, like online books, manuals etc. It is a Web application based on the client/server technology, so only browser is needed for work in a user-friendly environment. Besides using HTML editor, writing of books, textbooks, scripts and similar is possible in LaTeX (MathML) form which is converted into pdf document. LaTeX toolbar has a standard LaTeX tags for matrices, fields, bullets etc. and a pop-up window for a number of required symbols. Desired string is entered in the place of the cursor by clicking on its symbol. Source code is transferred into PDF document, which appears in the browser window and can be printed or saved on a local computer. Scriptrunner is an educational tool intended for all courses that use mathematics and computer programs, so the possibility of its usage is fairly wide.

This paper deals with the mathematical modeling of a dual action rodless pneumatic actuator controlled with a voltage-actuated proportional directional control valve. The use of pneumatic systems in position and force control applications that require high bandwidth is somehow difficult. This is mainly due to the nonlinear effects in pneumatic systems caused by the phenomena associated with air compressibility, nonlinear air flow through pneumatic system components, valve dead-band, significant friction effects in the moving parts, time delay caused by the connecting tubes, oscillations of air supply pressure, etc. In this paper we develop a detailed nonlinear mathematical model, which is used in a numerical simulation program and also we performed experiments for the model validation procedure. The model is based on an analysis of solenoid valve dynamic, thermodynamic changes in pneumatic system and equation of motion including significant nonlinear effects. This dynamic model of the system can be used to build more complex control structure and to develop high performance nonlinear controllers.

Scriptrunner is a web application that enables editing and running programs written in various programming languages. Currently supported languages are: C/C++, Java, Fortran, Pascal, PHP, HTML/Javascript, Matlab, Mathematica, Scilab and Octave. The goal of Scriptrunner is writing and publishing of digital books. Each such book becomes "live" because the programs with the preferred, regularly different, input data can be called from it. This article shows how to write a classbook for our students about linear and convex (semidefinite) programming, with many on-line examples. It is well known that most analysis and designs problems in robust and nonlinear control can be formulated as global optimization problems. In the last decade, optimization over LMIs has established itself as a popular convex relaxation technique in the systems and control community. We offer a useful on-line solution.

This work describes a set of modules for distance education. These modules have been developed by students as professional applications, and some of them are tested in the technical office. Modules can work as independent applications, but also can work connected and in this case they tend to make a system that enables users to elaborate, publish and exchange documents simultaneously with users communication, write and execute program code on-line, and to have knowledge testing - WEB exams

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Web learning of hydraulics is an application whose main goal is distributing knowledge and giving examples to students during studying hydraulic systems through an array of on-line interactive examples. A number of examples is suited for classes Hydraulics and pneumatics and covers basic hydraulic systems and hydraulic functional schemes, while other examples cover more complex systems and schemes.A student, user, is given an opportunity to change position of, for example, distributors, pressure in safety valve, pump power, etc. and at the same time, ability to see the changes on the screen and get the full calculation of a hydraulic system. Web hydraulics is written in JavaScript and MathML script language, which has enabled displaying of calculation of the system with necessary mathematical symbols in an HTML document. To use this application, users should have an Internet browser, free MathPlayer plug-in and Internet connection.

Thwe existence of symmetric block design for (71, 21, 6) was doubtful until the discovery of Z. Janko and T. van Trung of the so-called "non-human" design. In this paper we have classified designs with the above parameters, admitting all possible actions of the nonabelian group of order 21 on them, which is indeed the full automorphism group of the Janko-van Trung design. We have proved that there is only one symmetric block design for (71, 21, 6), together with its dual, with the Frobenius group of order 21, namely the Janko-van Trung design.

This paper is concerned with the modeling and control of a pneumatic rodless cylinder with on/off solenoid valves. Using some adequate control algorithms such as pulse-width modulation (PWM) techniques enable low-cost on/off valves to be used as a substitute for costly proportional valves in pneumatic servo applications. On this way a cheaper pneumatic servo system can be developed with characteristics close to a system, which uses proportional or servo valves. However, the use of solenoid two-way valves cause difficulties in modeling and control of pneumatic servo drives due to both discontinuity and non-linearity of the flow rate. Because of the delay of valve response and their discrete on/off characteristic a demanding control task is difficult to achieve. Without a suitable mathematical model and simulation process of the solenoid valves there is no effective method for controlling a pneumatic servo system. The experimental results are shown that the system performances with these valves are comparable to system control using a proportional valve.

U članku je ukratko, u osobnoj impresiji, predočen informatički razvitak i pregled informatičkih znanja koja su danas nužna u izobrazbi tehnici usmjerenog studenta. Prikazana su temeljna informatička područja: programiranje, baze podataka, procesna računala, računalne mreže i multimedija. Posebno su dotaknuta znanja potrebna informatičaru, kako bi se on mogao lako uklopiti u kompjutorski svijet tehnologijski najvećih, generičkih promjena. Člankom se posredno pokušava odgovoriti ne samo što, nego i zašto su nam baš ta znanja potrebna, te kako ih povezati s drugim znanjima u današnjoj fakultetskoj naobrazbi.

Program je nastao u čast 3. dolaska Sv. Oca Pape Ivana Pavla II Hrvatskoj. Glavne značajke: pregled Svetog pisma preko naslova i strukture, tražiteljska i motriteljska funkcija, najdraža mjesta, redovita misna čitanja, kolaboracija po temama, postavke. Pisan u Visual C & Basic programu. Skraćena inačica dosupna i preko WEB-a: Biblija On-Line.

Waterhammer WEB Simulation describes natural phenomenon at fluid streaming (especially in liquid) that has been suddenly stopped. Mathematical model of such non-steady flow is described with partial differential equations, which are insoluble analytically. Program was written with Mideva (Octave) program language. Input data values (pipe geometry, flow, liquid name, valve closure time etc.) can be entered on WEB site, where also can be seen simulation results. These results are displayed in graphical form, as diagrams, and show pressure and velocity time changes in different points of pipe.

RobotOnLine is the application for remote control of robot (mechanical manipulator) and transfer of video data over Internet, so that the user can have view on robot’ s work space together with numerical data. To use the application, the only software that is needed is the ordinary Web browser. RobotOnLine has been developed on PHP scripting language. It uses freely available, open source software: Apache and PHP.