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Wyszukujesz frazę "Voß, S." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
From transocean routes to global networks: a framework for liner companies to build service networks
Autorzy:
Shi, X.
Voss, S.
Powiązania:
https://bibliotekanauki.pl/articles/308099.pdf
Data publikacji:
2008
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
liner
port
logistics
networks
decision support systems
Opis:
During the previous two decades liner carriers within maritime shipping have broken the barriers from being pure transportation providers towards being logistics service providers. Most of the top 20 liner carriers worldwide hale set up spin-offs providing services from local booking up to 3rd party logistics services, combining the business advantages of tight linkages with liners together with the negotiation freedom with demanding customers by providing an extension of service coverage. Economical evaluations of transocean routes and global networks are of interest for decision makers responsible for business strategies as well as for operations. It is crucial to achieve appropriate judgements about which liner routes are profitable and how to build better service networks so that the companies' brand could be attractive to, e.g., ship- pers, including exporters, importers and forwarding agents. In this paper we discuss the corresponding trade-offs as well as related decision support systems of relevant service providers and companies.
Źródło:
Journal of Telecommunications and Information Technology; 2008, 3; 35-43
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Software tools for a multilayer network design
Autorzy:
Höller, H.
Voß, S.
Powiązania:
https://bibliotekanauki.pl/articles/309002.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
network design
GMPLS
SDH
WDM
Opis:
Today's long haul and metro high-speed networks are mainly based on synchronous digital hierarchy (SDH) or its American equivalent synchronous optical network (SONET) and wavelength division multiplex (WDM). On the other hand, the large amount of traffic growth during the last years has been caused mainly by Internet protocol (IP) traffic. Traditionally, the IP-router based networks and the cross-connect based synchronous networks are often planned and operated separately. However, in line with new developments such as generalized multiprotocol label switching (GMPLS), network providers begin to realize that the convergence of these two worlds promises significant benefits. A set of software tools to support the network designer has been developed and used on various kinds of real world network planning problems arising in the SDH/WDM context. This includes, among others, 1+1 protection planning, static restoration and dual homing issues. These tools are extended with additional features to handle aspects of the IP/SDH interplay in a GMPLS environment. The two main components are an AMPL based integer model (solved via CPLEX) and a heuristic implemented in C++.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 3; 57-63
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developing a Ring-Based Optical Network Structure with Glass-Through Nodes
Autorzy:
Caserta, M.
Schwarze, S.
Voß, S.
Powiązania:
https://bibliotekanauki.pl/articles/309201.pdf
Data publikacji:
2012
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
active nodes
interring traffic
optical transport network
ring network design
Opis:
An important issue in designing optical transport networks (OTN) is security. The concept of 1+1 protection requires to connect each origin-destination(OD)-pair by at least two node-disjoint paths. In the case of a single edge or node failure, the connection of all OD-pairs is maintained under 1+1 protection. On a ring, 1+1 protection is given naturally. Moreover, on rings, the routing effort is typically decreasing. These observations motivate the investigation of ring structures for OTN. When developing a ring structure for telecommunication networks, several subtasks can be identified. Ringshave to be designed, OD-pairs have to be assigned to rings, communication among rings has to be defined, a proper flow routing has to be chosen, and rings have to be dimensioned regarding flow capacity. In this paper, we address the first two issues, namely generation of rings and assignment of OD-pairs to rings. Our approach allows to distinguish active and non-active (glass-through) nodes in OTN. Active nodes are equipped with active routing hardware that weakens the optical signal and has impact on feasible ring lengths. Non-active nodes do not influence the optical signal. Although a consideration of active/non-active nodes is important in ring design, only a few references address this issue. We propose an algorithm for generating random ring candidates. Moreover, we present a mathematical model for the assignment of OD-pairs to rings subject to a feasible choice of active nodes. We test our methods using a case of Deutsche Telekom.
Źródło:
Journal of Telecommunications and Information Technology; 2012, 2; 13-20
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining hop-constrained spanning trees with repetitive heuristics
Autorzy:
Fernandes, M.
Gouveia, L.
Voß, S.
Powiązania:
https://bibliotekanauki.pl/articles/308588.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
hop-constrained spanning tree problem
metaheuristics
pilot method
rollout method
Opis:
The hop-constrained minimum spanning tree problem is the problem of determining a rooted spanning tree of minimum cost in which each path from the root node to any other node contains at most H hops or edges. This problem relates to the design of centralized tree networks with quality of service requirements (in telecommunications) and has a close relation with other tree problems. In this paper we investigate the adaptation of some well-known "repetitive" heuristics used for the capacitated minimum spanning tree problem to the hop-constrained minimum spanning tree problem and investigate some simple look ahead mechanisms for enhancing the quality of a savings heuristic. Computational results for a set of benchmark tests with up to 80 nodes are presented.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 4; 16-22
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Designing WDM networks by a variable neighborhood search
Autorzy:
Melian-Batista, B.
Höller, H.
Voss, S.
Powiązania:
https://bibliotekanauki.pl/articles/308920.pdf
Data publikacji:
2006
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
network design
WDM
SDH
variable neighborhood search
Opis:
With the ever-rising data volume that is demanded by the market, network planning in order to minimize the necessary investment while meeting the demands is constantly an important task for the network providers. Synchronous digital hierarchy (SDH) and wavelength division multiplex (WDM) form the core of many current backbone networks. In order to solve the provisioning and routing problem in such WDM networks, we develop a variable neighborhood search (VNS) metaheuristic. VNS is a metaheuristic that combines series of random and improving local searches based on systematically changed neighborhoods. An integer flow formulation is modeled in AMPL and solved by CPLEX in order to obtain optimal solutions as a reference for the heuristic.
Źródło:
Journal of Telecommunications and Information Technology; 2006, 4; 15-20
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extensions of the minimum labelling spanning tree problem
Autorzy:
Cerulli, R.
Fink, A.
Gentili, M.
Voss, S.
Powiązania:
https://bibliotekanauki.pl/articles/308930.pdf
Data publikacji:
2006
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
network design
metaheuristics
spanning trees
labelling trees
Steiner tree problem
Opis:
In this paper we propose some extensions of the minimum labelling spanning tree problem. The main focus is on the minimum labelling Steiner tree problem: given a graph G with a color (label) assigned to each edge, and a subset Q of the nodes of G (basic vertices), we look for a connected subgraph of G with the minimum number of different colors covering all the basic vertices. The problem has several applications in telecommunication networks, electric networks, multimodal transportation networks, among others, where one aims to ensure connectivity by means of homogeneous connections. Numerical results for several metaheuristics to solve the problem are presented.
Źródło:
Journal of Telecommunications and Information Technology; 2006, 4; 39-45
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Requirements of 4G-Based Mobile Broadband on Future Transport Networks
Autorzy:
Fricke, M.
Heckwolf, A.
Herber, R.
Nitsch, R.
Schwarze, S.
Voß, S.
Powiązania:
https://bibliotekanauki.pl/articles/309203.pdf
Data publikacji:
2012
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
backhauling
LTE advanced
mobile network de-sign
X2 interface
Opis:
Long term evolution technologies provide new standards in mobile communications regarding available bandwidth. It is expected that users of one radio cell will share more than 100 Mbit/s in future. To take advantage of the full feature set of next generation mobile networks, transport network design has to face new requirements, caused by the architectural changes of LTE technologies. Especially the newly defined X2 interface impacts on the transport network requirements. X2 enables direct communication between evolved base stations (eNBs) and thus, enforces local solutions. At the same time a tendency of locating network elements at fewer, central sites to reduce operational expenditure can be observed, in particular concerning the transport layer. This leads to the question of how the direct X2 connection of eNBs on the logical layer can be accommodated with a general centralization of transport networks. Our considerations show that for LTE, a centralized transport network is able to realize the local meshing between eNBs. However, for LTE Advanced, the standards currently discussed by the 3GPP initiative could lead to enhanced requirements on the X2 interface latency. Consequently, the implications for the network architecture have to be analyzed in more detail.
Źródło:
Journal of Telecommunications and Information Technology; 2012, 2; 21-28
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental changes in the central Baltic Sea during the past 1000 years: inferences from sedimentary records, hydrography and climate
Autorzy:
Leipe, T.
Dippner, J.W.
Hille, S.
Voss, M.
Christiansen, C.
Bartholdy, J.
Powiązania:
https://bibliotekanauki.pl/articles/47746.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
bottom water anoxia
sediment
hydrography
environment condition
little ice age
Baltic Sea
modern warm period
saline water
environment change
climate
Gotland Basin
Opis:
Short sediment cores from the eastern Gotland Basin were investigated using a multi-proxy approach in order to reconstruct the environmental conditions of the area during the past 1000 years. Sediment data and facies were discussed in relation to hydrographic features (salinity, oxygen) and climate change. During the medieval warm period (MWP), from about 900 to 1250 AD, the hydrographic and environmental conditions were similar to those of the present time (modern warm period, since about 1850): a temporally stable halocline, caused by regular saline water inflows from the North Sea, prevents vertical mixing and leads to bottom water anoxia and the deposition of laminated, organic-rich sapropels. During the period from about 1250 to 1850, referred to as the cold phase (including the Little Ice Age), the environmental conditions of the central Baltic Sea were distinctly different: the lower salinity, resulting from reduced North Sea water inflows, allowed vertical convection of the water column and long-term stable ventilation of the sea bed (oxic stage). Both the productivity of the planktonic ecosystem as well as the preservation of organic matter in the sediments improved during the warm periods. The anthropogenic impact can be identified within the recent laminated sequence by a temporal reconstruction of pollutant deposition. Our findings imply a climate-change driven shift in the environmental conditions and the ecosystem of the Baltic from the north to the south and back to the north.
Źródło:
Oceanologia; 2008, 50, 1; 23-41
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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