TOPOLOGICAL PLANNING OF COMMUNICATION NETWORKS

In this paper, we concentrate on topological planning process of large-scale communication networks such as those used by telecom operators. Such networks are usually spread over large geographical area, and finding an optimal topology is very important part of the planning process. Network equipment used in such network is very expensive, and two connection points can be hundreds of kilometers apart. These networks, in most cases, form a backbone network of telecom operator, meaning that majority of traffic is carried through high-speed communication links of such network. Any cable cuts or equipment malfunctions could result in huge data losses. Therefore, such networks require high degree of availability and fault resistance, which must be considered during the planning process. Network topology providing fault resistance should offer at least two separate communication paths between any pair of network nodes. Most important issue in network topology planning is finding topology with lowest possible overall network price, while keeping all requirements (such as fault tolerance, availability, maximal number of hops, maximal blocking probability etc.) satisfied. Network design process can be divided into three stages. First step is making decisions about which network elements (nodes, existing edges) should be included in a backbone network (for instance, one of sub-problems appearing in this phase is facility location problem). Second step includes selection of network topology, so that all elements selected in first step will be interconnected satisfying given requirements. Last phase is used to determine node and link capacities needed for successful traffic transport as well as routings of traffic demands, including protection. Depending on technologies used in network, different routing and protection mechanisms, as well as specific topology models, can be used (e.g. SDH/WDM SHR, mesh, dual-homing etc.)

Distribution of whales (order Cetacea) in Croatian part of the Adriatic sea

Dobri dupin (Tursiops truncatus) jedina je vrsta iz reda kitova sa stalnim boravištem u hrvatskom dijelu Jadranskog mora ali i Jadranu općenito. Nekoliko vrsta kitova zubana i samo jedna vrsta iz podreda usana povremeno se mogu naći na ovom području, no niti jedna od njih nema stalnu populaciju u Jadranu. Mnoge vrste kitova danas su zaštićene IUCN-ovom listom zaštite, a populacija dobrog dupina u Jadranu smatra se kritično ugroženom, te je zaštićena i zakonom Republike Hrvatske. U ovom radu navela sam osnovna obilježja kitova, opisala vrste koje se mogu naći u Jadranu i metode koje se koriste radi boljeg upoznavanja i zaštite ovih vrsta. S obzirom na situaciju u Hrvatskoj ali i u svijetu nužna je edukacija stanovništva o važnosti očuvanja navedenih kao i ostalih vrsta Jadranskog mora.Bottlenose dolphin (Tursiops truncatus) is the only whale species with a permanent residence in the Croatian part of the Adriatic sea and the Adriatic in general. There are a few more species of the toothed whales and one baleen whale that can occasionally be found in this area, but none with a permanent population. Today, many whales are under the IUCN protection. The Adriatic bottlenose dolphin population is defined as critically endangered and because of this it is also protected by Croatian law. In this work, I presented main whale characteristics, species which can be found in the Adriatic sea, and the methods which are used to get a better insight in their lives and ways in which we can protect them. Considering the fact that many whale species are endangered, it is really important to educate people about the importance of conservation of these as well as the other inhabitants of the sea

Pandemija COVID-19 i upravljanje krizom u Republici Hrvatskoj

The COVID-19 pandemic and the crisis that has affected all parts of the world, all industries and business processes, have significantly changed the usual way of life, introduced society to the ‘new normal’ and imposed the need for crisis management. Many organizations and countries were not ready for the crisis and consequently are suffering great consequences. The aim of this paper is to analyze how Croatia responded to this crisis from the aspect of the existing normative framework for crisis management and the operational solutions in practice, as well as to explore the role of the Government of the Republic of Croatia and its leaders in strategic decision making and interpretation of the crisis, and the extent to which homeland security and civil protection systems were put in function in managing the crisis. As an additional aim, the paper intends to mark a certain number of contradictions, controversies and paradoxes that arose during the crisis, as well as certain observations that can serve for further analysis and elements in the lessons learned process.Pandemija COVID-19 i kriza koja je zahvatila sve dijelove svijeta, sve industrije i poslovne procese, znatno su promijenili uobičajen način života svih ljudi, uveli društvo u "novo normalno" i nametnuli potrebu upravljanja krizom. Mnoge organizacije i države nisu spremne dočekale krizu te imaju velike posljedice. Cilj je ovog rada analizirati kako je Hrvatska reagirala na tu krizu s aspekta postojećega normativnog okvira upravljanja krizama i operativnih rješenja u praksi, istražiti ulogu Vlade Republike Hrvatske i njezinih čelnih ljudi u donošenju strateških odluka i tumačenju krize, kao i utvrditi u kojoj su mjeri korišteni sustavi domovinske sigurnosti i civilne zaštite u upravljanju krizom. Osim toga, cilj je rada zabilježiti određen broj kontradiktornosti, kontroverzija i paradoksa koji su se pojavili tijekom krize, kao i određena zapažanja koja mogu poslužiti za buduće analize i iskustva u procesu učenja

Croatian Tourism Sector and Crisis Management - A Case Study Related to the COVID-19 Pandemic

Tourism is an extremely important economic sector for the Republic of Croatia and an important component of certain economic and social activities, such as transport and business of travel agencies, trade, catering, agriculture, and numerous service activities. Many Croatian citizens are directly, indirectly, or partially employed in the said sectors. Many depend on it – from individuals, through various business entities and tourist destinations, to the state itself which generates almost 20 percent of the annual state budget revenue from tourism. Given the multilevel and multifunctional importance of tourism, it is important to research how it is organized for emergencies that can cause significant disruptions in the operation and revenue generation. The goal of this paper is to analyze how and how successfully the tourism sector coped with the COVID-19 pandemic and the resulting crisis, what crisis management mechanisms were developed and how they were used during 2020

Distribution of Mercury Species in the Water Column of the Stratified Krka River Estuary

Investigation of the mercury speciation (total/reactive and dissolved/ /particular forms) was carried out in waters of the highly stratified Krka River Estuary. The concentrations obtained are in satisfactory agreement with those obtained for other unpolluted aquatic environments (0.5-2.5 ng/L for total mercury, 0.1-0.8 ng/L for dissolved mercury and 0.04-0.75 pg/g for particulate mercury, 0 > 0.45 pm). Two or three discernible water layers (the upper fresh or brackish water layer, deeper saline layer and the in-between intermediate water layer) revealed different distribution of mercury species. In the upper freshwater layer with low salinity, the fraction of reactive mercury varied considerably with salinity changes (10-100% of the total), both during a single sampling campaign, as well as between particular sampling periods which coincided with different seasons and river regimes. This generally corresponded to the dissolved mercury fraction, confirming the insignificance of the organically bound dissolved mercury. In the bottom saline layer, mercury was mostly reactive (80-100% of the total), and even a part of the particulate mercury behaved as labile toward SnCl2 reduction. In the upper water layer (low-salinity), the largest fraction of mercury was bound to particles, which were mostly of biological origin (plankton), except in the lower part of the estuary, where the particles were of anthropogenic origin (municipal waste discharge from the city of Šibenik). Accumulation of mercury, both in reactive and particulate form, was observed at the halocline, e.g. at the fresh/saline water interface (FSI)

A Device for the Measurement of Thermoelectric Force in Biopolymer Samples

The construction and operation of a device for the measurement of the thermoelectI1ic force (Seebeck effect) is described. The device i:s suitable for the work with oriented biopolymer samples (DNA salts) of high resastivity in the temperature range between - 30 °c and + 30 °c

Planning of Material Consumption in Serial Production of the Castings

The production of castings can be considered as production in transport. Is necessary to plan and supply the huge quantity of different materials. The expenses of these materials reach 80 % of all expenses which give the importance to planning of working materials for serial production. To perform all mentioned in planning phase of production is necessary to define satisfactory method of determination of kind and quantity of working materials and carriers of necessary information for planning. As entrance have information from Operational sheet, List of operations and List of tools

Propusnost kod projektiranja procesa izrade čeličnih cijevi

Conventional approach to pipe manufacturing process design is using capacity to satisfy maximal load for each process. In the new approach, throughput is suggested as a basic determinant aiming at finding dynamic balance among following and previous process phases. Throughput is defined by the interval of time between product exiting from the preceding process phase and its entry to the next one. Interval of time for the product delivery from the preceding phase must be less or equal as the amount of time necessary for activating the next phase. Knowing the performances of the next phase one can impact to the characteristics of the preceding phase. Throughput can be also used as a more precise way for observed process productivity measurement. Such approach is suggested and for other complex technological processes.Konvencionalni pristup projektiranju procesa izrade cijevi koristi kapacitet kako bi se zadovoljilo maksimalno opterećenje u svakom trenutku procesa. U novom se pristupu kao temeljna odrednica predlaže propusnost, koja teži iznalaženju dinamičke ravnoteže narednih i prethodnih faza procesa. Propusnost se definira međuvremenima izlaza proizvoda iz jedne faze procesa i ulaska u narednu, gdje međuvrijeme isporuke proizvoda iz promatrane faze, mora biti manje ili jednako vremenu potrebnom za aktiviranje naredne faze. Tako je moguće, poznavajući performanse narednog procesa, utjecati na karakteristike onog promatranog. Propusnost se koristi i kao precizniji način mjerenja učinkovitosti promatranog procesa. Pristup se može koristiti i za druge složene tehnološke procese