Formal description technique SDL for manufacturing systems specification and description

This paper addresses the formal specification and description of manufacturing systems. It is considered the use of SDL (Specification and Description Language), a standard FDT (Formal Description Technique), to model the behaviour, data and structure aspects of a manufacturing system. SDL was originally developed for telecommunication systems (protocol specification and data processing). The adequacy of FDTs, namely SDL, for the manufacturing systems domain is investigated by developing the SDL specification of part of a Distributed/Virtual Manufacturing System cell installation (D/V MS Project), and analysing it

Man-Machine interface for remote programming and control of NC machine-tools at the task level: an example

This paper presents an example of Man-Machine Interface for remote programming and control of NC machine tools. The system is based on a computer virtual panel which substitutes the machine control panel and in telematics interfaces which establishes the basis for geographical independence between the physical equipment and human operator

Using formal description technique ESTELLE for manufacturing systems specification or description

Usually the description of a system is given in natural language or in diagrams. It is very hard to make this kind of informal description clear, concise and unambiguous. Implementations based on informal specifications are usually prone to errors, omissions and incompatibilities. This paper presents an attempt to introduce Formal Description Techniques (FDT's), originally developed for the area of telecommunications and data transfer, as a mean for the specification/description of manufacturing systems. A brief introduction on standard FDT's, LOTOS, ESTELLE and SDL is given. Several concepts were behind the development of these techniques and this paper exploits the extended finite state machine (EFSM) concept as a suitable form for specification/description of manufacturing systems using FDT ESTELLE

Influence of Acidity and Extraction Time on the Recovery of Flavonoids from Grape Skin Pomace Optimized by Response Surface Methodology

Grape pomace is recognized as an economical source for the recovery of a large number of biologically active compounds, such as polyphenols. Grape pomace extracts can be successfully used as raw material for functional foods production, since they are generally recognized as safe for the food industry. This study aimed to quantify the amounts of recovered flavonoids (total flavonoids, proanthocyanidins, anthocyanins, and flavonols) from grape skin pomace (Vitis vinifera L. cv. Merlot) under conventional extraction with different acidities (0.5 % – 1 % HCl) and lengths of extraction time (30–60 minutes). The grand average values in this study were as follows: (i) proanthocyanidins 12.08±0.25 mg CE g–1 d.m., (ii) anthocyanins 2.17±1.02 mg Mvd-3-glc g–1 d.m., (iii) flavonols 7.73±0.11 mg QE g–1 d.m., and (iv) total flavonoids 36.28±0.42 mg QE g–1 d.m. The amounts of studied polyphenols generally increased with acidity and length of extraction time. This relation was more evident for flavonols and total flavonoids, while less clear for other examined phenolics

Uticaj kadmijuma na klijanje semena i rast pšenice

In this study, the effect of Cd on the germination, growth of seedlings and composition of plants deriving from contaminated grains, grown in the field, was examined. Wheat grains were soaked in Cd-containing solutions: 0 (control, deionized water), 10-5 , 10-4 , 10-3 , and 10-2 M CdCl 2 during 24h. One portion of grains was used to test germination and seedling growth, while the other was sown in the field. The concentration of Cd in the grains almost linearly increased with the increase in the applied concentrations of Cd, which reduced the germination and energy of germination and increased the proportion of atypical seedlings. Larger concentrations of Cd significantly impaired the growth of seedlings (length of the shoots and roots, dry matter mass). In the grains of the field-grown plants the concentrations of N, P, and K were not affected by Cd, but their concentrations in the straw declined (especially of N). These results suggest that the emergence and development of plants on the soil polluted by Cd are likely to be significantly limited and yield reduced.Kadmijum (Cd) je potencijalni zagađivač sredine živih organizama i pri većim koncentracijama odlikuje se jakim fitotoksičnim dejstvom. U radu je u laboratorijskim uslovima proučeno dejstvo različitih koncentracija kadmijuma na klijanje i rast mladih biljaka pšenice, a u poljskim uslovima njegov uticaj na koncentraciju mineralnih materija u zrnu i slami u fazi pune zrelosti biljaka, koje su potekle od zrna tretiranog kadmijumom. S povećanjem koncentracije kadmijuma u fazi bubrenja semena skoro se linerano povećala njegova koncentracija u semenu. Utvrđeno je da veće koncentracije kadmijuma značajno smanjuje klijanje i energiju klijanja semena, a povećavaju učešće atipičnih klijanaca i neproklijalog semena. Veće koncentracije kadmijuma značajno su smanjile rast mladih biljaka kao i masu njihove suve materije. Rast nadzemnog dela i korena smanjen je u većoj meri od mase suve materije, na osnovu čega se može zaključiti da je kadmijum u većoj meri uticao na faktore rasta nego na stvaranje suve mase. Najveća primenjena koncentracija kadmijuma smanjila je hidratisanost 68 nadzemnog dela mladih biljaka. Bubrenje semena u prisustvu različitih koncentracije kadmijuma nije uticalo na koncentraciju azota, fosfora i kalijuma u zrnu, a smanjilo je njihovo prisustvo u slami, naročito azota na kraju vegetacije. Dobijeni rezultati potvrđuju nalaze ranijih istraživanja kod drugih biljnih vrsta na osnovu kojih su fiziološki i biohemijski procesi klijanja semena značajno inhibirani u prisustvu većih koncentracija kadmijuma. Na osnovu navedenog može se predvideti da će na zemljištu zagađenom kadmijumom nicanje useva i rast mladih biljaka pšenice biti ograničeno, što će se nepovoljno odraziti na prinos useva

Odnos koncentracije zemnoalkalnih metala kalcijuma, barijuma i stroncijuma u zrnu diploidne, tetraploidne i heksaploidne pšenice

Even though calcium (Ca), strontium (Sr) and barium (Ba) belong to the same group of the periodic table of elements, and thus have similar chemical features, their importance for plants differs greatly. Since plants do not have the ability to completely discriminate between essential (e.g. Ca) and non-essential elements (e.g. Sr and Ba), they readily take all of them up from soil solution, which is reflected in the ratios of concentrations of those elements in plant tissues, and it influences their nutritive characteristics. The ability of plant species and genotypes to take up and accumulate chemical elements in their different tissues is related to their genetic background. However, differences in chemical composition are the least reflected in their reproductive parts. Hence, the aim of this study was to evaluate ratios of concentrations of Ca, Sr and Ba in the whole grain of diploid and tetraploid wheat ‒ ancestors of common wheat, as well as in hexaploid commercial cultivars, grown in the field, at the same location, over a period of three years. The investigated genotypes accumulated Ca, Sr and Ba at different levels, which is reflected in the ratio of their concentrations in the grain. The lowest ratio was established between Ba and Sr, followed by Ca and Ba, while the highest ratio was between Ca and Sr. Moreover, the results have shown that the year of study, genotype and the combination highly significantly affected the ratio of the concentration Ca:Sr, Ca:Ba, and Ba:Sr.Kalcijum (Ca), stroncijum (Sr) i barijum (Ba) pripadaju istoj grupi elemenata Periodnog sistema i imaju slične hemijske osobine. Međutim, njihove uloge u biljnom organizmu veoma se razlikuju. Obzirom da biljke nemaju sposobnost da u potpunosti razlikuju esencijalne (C a) od neesencijalnih elemenata (Sr i B a), one ih sve usvajaju iz zemljišnog rastvora, a to se odražava u različitom odnosu koncentracija ovih elemenata u biljnom tkivu i utiče na njihove nutritivne osobine. Sposobnost vrsta i genotipova da usvajaju i akumuliraju hemijske elemente u različitim tkivima, zavisi od njihove genetike. I pored toga, razlike u hemijskom sastavu ogledaju se u njihovoj reproduktivnoj ulozi. Cilj istraživanja bio je da se odrede odnosi koncentracija Ca, Sr i Ba u celom zrnu diploidne i tetraploidne pšenice - pretka današnje pšenice, kao i heksaploidnih komercijalnih vrsta, gajenih na istom polju i lokalitetu tokom tri godine. Ispitivani genotipovi su akumulirali Ca, Sr i Ba u različitim količinama, što se odrazilo na odnos njihovih koncentracija u zrnu. Najniži odnos ustanovljen je između Ba i Sr, zatim Ca i Ba, a najveći između Ca i Sr. Takođe, rezultati su pokazali da godina ispitivanja , genotip i kombinacija značajno utiču na odnos koncentracije Ca:Sr, Ca:Ba i B a:Sr

Distributed/virtual manufacturing system cell: an experimental installation

The main objectives of the “Distributed/Virtual Manufacturing System (D/V MS) Cell” project are: (1) The development of Tele-services technologies and organisation for the production planning and control functions; (2) The development of permanent high performance laboratory facilities that enable development and demonstration of D/V MS design and control, i.e., global distribution of production planning and control functions; (3) The development of an abstract environment, i.e., a virtual environment for design and real time control of manufacturing systems, or one of its elements, independent of the physical implementations. The D/V MS Cell satisfies the defined hierarchical distributed control model The Hardware System of the D/V MS Cell is composed by: (1) Machine tool cell: CNC milling machine, external sensors and actuators, interface computer with communications links, (2) Machine cell: Two machine simulators, PLC, sensors and actuators, computer based local controller, (3) Robot cell: Robot SCORBOT ER-VII, artificial vision system, conveyor system, computer based local controller, (4) Control centre: Video projector, computer based remote controller, computer based real time video and audio system. The Software System of the D/V MS Cell is composed by: (1) Applications for Human-Computer Interface (HMI): Interfaces for machine tool and robot programming and control, interface for production planning and control, (2) Computer-Machine Interface, via RS-232C, (3) Computer-Computer Interface, for communications via Internet. The hardware structure of the (D/V MS) Cell is already implemented and interfaces for machine tool programming and control are developed (software system). The operation of the complete system is planned for the year 1999

Problem zaštite obrazovno-vaspitnih ustanova od visokotehnološkog kriminala i elektronskog nasilja

The article analyses the problems that appear in the process of protecting the educational institutions from the security risks in cyber space - cyber crime and cyberbullying. Due to main characteristics and nature of security risks in cyber space, children, adolescents and students are particularly vulnerable category of Internet users. Having this on mind, we can conclude that educational institutions are an important factor in the process of prevention and control of security risks that young people face in cyber space. The authors analyze the legal framework and the actual situation in this domain and propose concrete measures for the reduction of security risks in cyber space, and consider the capacities and importance of building and implementing the unique, functional and pragmatic multi-layer protection model. The first part of the article is dedicated to the analyses of the legal framework for countering cyber crime, with the consideration of the normative legal acts that regulate the protection of children and students from the violence, malestation and neglection in the school environment. The authors also focus on the legal definition of cyberbullying. In the second part of the article, the authors propose the principles and elements for building a model of multi-layer protection and analyze the possibility of its application in educational institutions in the Republic of Serbia, as an efficient tool for the prevention and reduction of security risks in the cyber space.Članak je posvećen razmatranju problema zaštite obrazovno-vaspitnih ustanova od visokotehnološkog kriminala i elektronskog nasilja. Imajući u vidu prirodu visokotehnološkog kriminala, može se konstatovati da posebno ranljivu kategoriju korisnika Interneta predstavlja populacija mladih: dece, adolescenata i studenata. Obrazovno-vaspitne ustanove predstavljaju važan činilac u procesu prevencije i suzbijanja bezbednosnih rizika kojima su mladi izloženi u sajber prostoru. Autori analiziraju postojeće normativno i faktičko stanje u ovom domenu i predlažu konkretne mere za redukciju ovih bezbednosnih rizika, te ukazuju na mogućnost i značaj izgradnje i implementacije višeslojnog modela zaštite. U prvom delu rada analizirana je domaća pravna regulativa u oblasti visokotehnološkog kriminaliteta. Imajući u vidu specifičnost predmeta istraživanja, autori analiziraju i odredbe zakonskih i podzakonskih propisa u oblasti zaštite dece od nasilja, zlostavljanja i zanemarivanja u obrazovno-vaspitnim ustanovama, fokusirajući se na norme o tzv. elektronskom nasilju. U drugom delu rada autori predlažu principe i elemente za izgradnju modela višeslojne zaštite i analiziraju mogućnost njegove primene u obrazovnim ustanovama u Republici Srbiji, a u cilju prevencije rizika iz širokog spektra visokotehnološkog kriminaliteta

Analysis of lot-sizing methods’ suitability for different manufacturing application scenarios oriented to MRP and JIT/Kanban environments

Goal: The main goal of this research is to analyse the behaviour of a set of ten lot-sizing methods applied to different application scenarios, within the context of more traditional MRP-based manufacturing environments and on JIT/ Kanbans oriented ones.Design/Methodology/Approach: After an extended literature review, a quantitative research method is used to provide a comparative analysis on the performance of the lot-sizing methods under different simulated application scenarios, with variations in demand and peaks of seasonality. Moreover, a final summary provides the error deviations for lot-sizing methods regarding increases in demand variations and seasonality indexes.Results: The study analyses lot-sizing methods and discusses benefits and risks associated to its use in application scenarios marked by a considerable variation in demand or peaks in seasonality.Limitations of the investigation: As the application scenarios did not explore variations in the ordering and stock holding costs, further analysis including these kinds of variations is encouraged.Practical implications: The findings of this research enable the enhancement of the conscience of industrial practitioners, regarding the selection of best suited lot-sizing methods for being applied on each kind of manufacturing scenario, regarding MRP or JIT/Kanban environments.Originality/Value: Given the diversity of the existing lot-sizing methods, for instance, the heuristic ones, authors can find it quite difficult to select appropriate methods for solving their problems for each kind of application scenario. Therefore, the present study can provide useful knowledge to better support decision making in the lot-sizing domain.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019