1. Global logistic network of courier services for the 21st centuryRatko Zelenika, Sabina Kamnik Zebec, Helga Pavlić, 2006, pregledni znanstveni članek Opis: The development of logistics has contributed a lot to all the branches of economy. A successful economic subject cannot exist without a well-developed logistic branch. The organization of logistics has become a strategic element of the policy making of enterprises. Modern logistics enables us to bring into line different interests in material flow management. Global organizers of logistic services are developing and specialising in some essential services, such as combining of cargo into assembly consignements and also their distribution. The biggest global tenderers of logictic services are considered (DHL, TNT, FEDEX, UPS, etc).
Ključne besede: traffic, transportation, logistics, logistic services, TNT, DHL, FEDEX, UPS, global logistic networks
Objavljeno v DKUM: 02.06.2017; Ogledov: 1472; Prenosov: 186
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2. Dynamic optimization in supply chainsDrago Pupavac, Jasmina Pašagić Škrinjar, Ratko Zelenika, 2007, izvirni znanstveni članek Opis: Production and stock optimization in supply chains is a complex problem because it determines the optimum quantity production in time. Due to their multileveld nature, those problems are mostly solved by different methods and models of dynamic programming. The problem discussed in this paper refers to the determination of optimum quantity of production and stocks within the supply chain in a certain period of time, as well as in each sub-interval of a period, but with the condition that the production and stock expenditure remains minimal and that the predetermined demand in every sub-interval and throughout the entire observation period remains satisfied.
Ključne besede: transportation, logistics, transportation networks, supply chains, optimization, dynamic programming, traffic
Objavljeno v DKUM: 02.06.2017; Ogledov: 1490; Prenosov: 187
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3. Computer-supported modelling of multimodal transportation networks rationalizationRatko Zelenika, Slavomir Vukmirović, Hilmija Mujić, 2007, drugi znanstveni članki Opis: This paper deals with issues of shaping and functioning of computer programs in the modelling and solving of multimodal transportation network problems. A methodology of an integrated use of a programming language for mathematical modelling is defined, as well as spreadsheets for the solving of complex multimodal transportation network problems. The paper contains a comparison of the partial and integral methods of solving multimodal transportation networks. The basic hypothesis set forth in this paper is that the integral method results in better multimodal transportation network rationalization effects, whereas a multimodal transportation network model based on the integral method, once built, can be used as the basis for all kinds of transportation problems within multimodal transport. As opposed to linear transport problems, multimodal transport network can assume very complex shapes. This paper contains a comparison of the partial and integral approach to transportation network solving. In the partial approach, a straight forward model of a transportation network, which can be solved through the use of the Solver computer tool within the Excel spreadsheet interface, is quite sufficient. In the solving of a multimodal transportation problem through the integral method it is necessary to apply sophisticated mathematical modelling programming languages which support the use of complex matrix functions and the processing of a vast amount of variables and limitations. The LINGO programming language is more abstract than the Excel spreadsheet, and it requires a certain programming knowledge. The definition and presentation of a problem logic within Excel, in a manner which is acceptable to computer software, is an ideal basis, for modelling in the LINGO programming language, as well as a faster and more effective implementation of the mathematical model. This paper provides proof for the fact that it is more rational to solve the problem of multimodal transportation networks by using the integral, rather than the partial method.
Ključne besede: intermodal transportation, transportation networks, spreadsheets, mathematical modelling, programming languages, Lingo, Solver
Objavljeno v DKUM: 01.06.2017; Ogledov: 1387; Prenosov: 119
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4. Modeling the large scale disruptions of an airline networkMilan Janić, 2005, izvirni znanstveni članek Opis: When the large-scale disruptions of airline networks occur, they can cause significant deterioration of the planned schedule. Such deterioration shows upin the form of long delays, rerouting and/or cancellation of flights. This paper presents a model for assessment of the economic consequences of large-scale disruptions of an airline single hub-and-spoke network. These consequences are expressed by the cost of delayed and cancelled complexes of flights. The model is based on the theory of queuing systems with the airline hub airport as a server and the complexes of flights as customers. The difference between the service time of the affected and planned complexes determine their delays caused by a given disruptive event. The cost of delays and revenues of the affected flights, and global airline mitigating strategies are used to determine the total airline cost of delayed and cancelled complexes. The model is applied to the disrupted hub-and-spoke network of a large European airline. The purpose is to illustrate the model's planning nature, complexity of the problem, influence of the relevant factors,and the magnitude of the economic consequences.
Ključne besede: air transportation, airlines, networks, delay time
Objavljeno v DKUM: 05.06.2012; Ogledov: 1950; Prenosov: 100
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