281. Punish, but not too hard: how costly punishment spreads in the spatial public goods gameDirk Helbing, Attila Szolnoki, Matjaž Perc, György Szabó, 2010, izvirni znanstveni članek Opis: We study the evolution of cooperation in spatial public goods games where, besides the classical strategies of cooperation (C) and defection (D), we consider punishing cooperators (PC) or punishing defectors (PD) as an additional strategy. Using a minimalist modeling approach, our goal is to separately clarify and identify the consequences of the two punishing strategies. Since punishment is costly, punishing strategies lose the evolutionary competition in case of wellmixed interactions. When spatial interactions are taken into account, however, the outcome can be strikingly different, and cooperation may spread. The underlying mechanism depends on the character of the punishment strategy. In the case of cooperating punishers,increasing the fine results in a rising cooperation level. In contrast, in the presence of the PD strategy, the phase diagram exhibits a reentrant transition as the fine is increased. Accordingly, the level of cooperation shows a nonmonotonous dependence on the fine. Remarkably, punishing strategies can spread in both cases, but based on largely different mechanisms, which depend on the cooperativeness (or not) of punishers. Ključne besede: evolutionary game theory, public goods, spatial games, punishment, social systems, moral Objavljeno: 03.07.2017; Ogledov: 379; Prenosov: 169 Celotno besedilo (823,76 KB) Gradivo ima več datotek! Več...

282. Management concepts transformation in SloveniaDuško Uršič, Marjan Pivka, 2000, izvirni znanstveni članek Opis: In the last ten years Slovenia has been faced with a quite holistic transition of general social and organisation life. In our paper, first of all, we will emphasise the model of transition of management in Slovenia with presentation of field research results from our several years lasting research of management in Slovenia. The presented model of transition is based on the systems approach as our methodological version of systems thinking. This approach has been developed by our team since 1992 and it allowed research of way of thinking of managers about the transition of management concepts and effects of prevailed application projects, both at the same time and in interaction. Ključne besede: Slovenia, transition, transition economics, management, organization, research, models, systems, company theory, system theory, thinking Objavljeno: 04.07.2017; Ogledov: 197; Prenosov: 33 Celotno besedilo (531,19 KB) Gradivo ima več datotek! Več...

283. A class of modified Wiener indicesIvan Gutman, Damir Vukičević, Janez Žerovnik, 2004, izvirni znanstveni članek Opis: The Wiener index of a tree T obeys the relation W(T) = Σen1(e) • n2(e) where n1(e) and n2(e) are the number of vertices on the two sides of the edge e, and where the summation goes over all edges of T. Recently Nikolić, Trinajstić and Randić put forward a novel modification mW of the Wiener index, defined as mW(T) = Σe[n1(e) • n2(e)]–1. We now extend their definition as mWλ(T) = Σe[n1(e) • n2(e)]λ, and show that some of the main properties of both W and mW are, in fact, properties of mWλ, valid for all values of the parameter λ≠0. In particular, if Tn is any nvertex tree, different from the nvertex path Pn and the nvertex star Sn, then for any positive λ, mWλ(Pn) > mWλ(Tn) > mWλ(Sn), whereas for any negative λ, mWλ(Pn) < mWλ(Tn) < mWλ(Sn). Thus mWλ provides a novel class of structuredescriptors, suitable for modeling branchingdependent properties of organic compounds, applicable in QSPR and QSAR studies. We also demonstrate that if trees are ordered with regard to mWλ then, in the general case, this ordering is different for different λ. Ključne besede: graph theory, chemical graph theory, modified Wiener index, NikolićTrinajstićRandić index, branching Objavljeno: 05.07.2017; Ogledov: 314; Prenosov: 57 Celotno besedilo (125,08 KB) Gradivo ima več datotek! Več...

284. Computing the Szeged indexJanez Žerovnik, 1996, izvirni znanstveni članek Opis: We give an explicit algorithm for computing the Szeged index of a graph which runs in ▫$O(mn)$▫ time, where ▫$n$▫ is the number of nodes and ▫$m$▫ is the number of edges. Ključne besede: mathematics, chemistry, chemical graph theory, molecular graphs, structural formulae, algorithms, topological index, Szeged index Objavljeno: 05.07.2017; Ogledov: 232; Prenosov: 43 Celotno besedilo (1,83 MB) Gradivo ima več datotek! Več...

285. 
286. Corroborating a modification of the Wiener indexIvan Gutman, Janez Žerovnik, 2002, kratki znanstveni prispevek Opis: In a recent work [Chem. Phys. Lett. 333 (2001) 319321] Nikolić, Trinajstić, and Randie put forward a novel modification ▫$^m$▫W of the Wiener index. We now show that ▫$^m$▫W possesses the basic properties required by a topological index to be acceptable as a measure of the extent of branching of the carbonatom skeleton of the respective molecule (and therefore to be a structuredescriptor, potentially applicable in QSPR and QSAR studies). In particular, if ▫$T_n$▫ is any nvertex tree, different from the nvertex path ▫$P_n$▫ and the nvertex star ▫$S_n$▫, then mw(Pn) < mW(Tn) < mW(Sn). We also show how the concept of the modified Wiener index can be extended to weighted molecular graphs. Ključne besede: graph theory, distance, molecular graphs, modified Wiener index, weigted modified Wiener index, branching, chemical graph theory Objavljeno: 05.07.2017; Ogledov: 232; Prenosov: 33 Celotno besedilo (85,05 KB) Gradivo ima več datotek! Več...

287. The HosoyaWiener polynomial of weighted treesBlaž Zmazek, Janez Žerovnik, 2007, izvirni znanstveni članek Opis: Formulas for the Wiener number and the HosoyaWiener polynomial of edge and vertex weighted graphs are given in terms of edge and path contributions. For a rooted tree, the HosoyaWiener polynomial is expressed as a sum of vertex contributions. Finally, a recursive formula for computing the HosoyaWiener polynomial of a weighted tree is given. Ključne besede: mathematics, graph theory, HosoyaWiener polynomial, weighted tree, vertex weighted graphs Objavljeno: 05.07.2017; Ogledov: 341; Prenosov: 35 Celotno besedilo (182,69 KB) Gradivo ima več datotek! Več...

288. Wiener numbers of pericondensed benzenoid hydrocarbonsSandi Klavžar, Ivan Gutman, Amal Rajapakse, 1997, izvirni znanstveni članek Opis: Using a recently developed technique for the calculation of the Wiener number (W) of benzenoid systems, we determine explicit expressions for W for several homologous series of pericondensed benzenoid hydrocarbons. An elementary proof for the correctness of the used method is also included. Ključne besede: mathematics, chemical graph theory, distance in graphs, Wiener number, benzenoids Objavljeno: 05.07.2017; Ogledov: 311; Prenosov: 41 Celotno besedilo (16,93 MB) Gradivo ima več datotek! Več...

289. Multicriteria and econometric evaluation of dairy productsKarmen Pažek, Jernej Turk, Sebjan Hari, Črtomir Rozman, Jernej Prišenk, 2014, izvirni znanstveni članek Opis: This study examined the multicriteria assessment of four dairy products: "Pomursko mlejko" (Pomurje milk), "Lejko mleko" (light milk), "Fyto mleko" (Fyto milk) and "Posneto mleko v prahu" (dried milk). The research was executed by using a multicriteria methodology, DEX, which was complemented by an econometric analysis for light milk to estimate the trends in production and consumption before analyzed dairy products were implemented on the market. DEXi computer program results indicated that all analyzed milk products were 'above average'. The econometric model was applied to examine changes in the demand for lowfat milk (light milk). Empirical results showed significant consumer response to the increase in the prices of lowfat milk demonstrating income elasticity (1,15 unit). Ključne besede: multiattribute decision theory, DEXi, econometric analysis, milk products Objavljeno: 10.07.2017; Ogledov: 322; Prenosov: 49 Celotno besedilo (636,19 KB) Gradivo ima več datotek! Več...

290. 