Measurement-device-independent quantum key distribution over untrustful metropolitan network

Quantum cryptography holds the promise to establish an information-theoretically secure global network. All field tests of metropolitan-scale quantum networks to date are based on trusted relays. The security critically relies on the accountability of the trusted relays, which will break down if the relay is dishonest or compromised. Here, we construct a measurement-device-independent quantum key distribution (MDIQKD) network in a star topology over a 200 square kilometers metropolitan area, which is secure against untrustful relays and against all detection attacks. In the field test, our system continuously runs through one week with a secure key rate ten times larger than previous result. Our results demonstrate that the MDIQKD network, combining the best of both worlds --- security and practicality, constitutes an appealing solution to secure metropolitan communications.Comment: 17 pages, 4 figure

Monolithic WDM Sources And Detectors For The Long Wavelength Fiber Band Based On An InP Grating Multiplexer/demultiplexer

Wavelength Division Multiplexed (WDM) networks are currently attracting considerable attention worldwide. Applications envisaged are wide-ranging - from computer back-plane interconnects and the telephone local loop, through local- and metropolitan- area networks, to wide-area networks involving advanced wavelength routing schemes [1, 2]

Adjacency Matrix Based Energy Efficient Scheduling using S-MAC Protocol in Wireless Sensor Networks

Communication is the main motive in any Networks whether it is Wireless Sensor Network, Ad-Hoc networks, Mobile Networks, Wired Networks, Local Area Network, Metropolitan Area Network, Wireless Area Network etc, hence it must be energy efficient. The main parameters for energy efficient communication are maximizing network lifetime, saving energy at the different nodes, sending the packets in minimum time delay, higher throughput etc. This paper focuses mainly on the energy efficient communication with the help of Adjacency Matrix in the Wireless Sensor Networks. The energy efficient scheduling can be done by putting the idle node in to sleep node so energy at the idle node can be saved. The proposed model in this paper first forms the adjacency matrix and broadcasts the information about the total number of existing nodes with depths to the other nodes in the same cluster from controller node. When every node receives the node information about the other nodes for same cluster they communicate based on the shortest depths and schedules the idle node in to sleep mode for a specific time threshold so energy at the idle nodes can be saved.Comment: 20 pages, 2 figures, 14 tables, 5 equations, International Journal of Computer Networks & Communications (IJCNC),March 2012, Volume 4, No. 2, March 201

VoIP Traffic Shaping Analyses in Metropolitan Area Networks

This paper represents VoIP shaping analyses in devices that apply the three Quality of Service techniques – IntServ, DiffServ and RSVP. The results show queue management and packet stream shaping based on simulation of the three mostly demanded services – VoIP, LAN emulation and transaction exchange. Special attention is paid to the VoIP as the most demanding service for real time communication

Balkanisation of telecommunication networks and regional development : a network economics approach (In French)

The paper focuses on the links between telecommunication networks and local development, emphasizing on the peculiar case of Metropolitan Area Networks (MAN). From tools of network economics, the paper studies the market dynamics of telecommunication networks and the infrastructure diffusion from metropolitan regions to peripheral ones. This market dynamics shows that the infrastructure offering by local communities can contribute to local development only if regulation mechanisms of co-operation between local public institutions are instituted.metropolitan area networks, network economics, competition/co-operation, local communities, local development

An Alternative Design Topology for Metropolitan Area Networks

One of the key issues in designing a network topology is vulnerability. The vulnerability parameter measures the resistance of a network to disruption of operation  after  the  failure  of  certain  stations  or  communication  links.  One counter-measure  to address  the vulnerability of a network is edge connectivity.In this paper, a  more selective concept of edge  connectivity is introduced, called component  order  edge  connectivity  for  MAN  topology  design.  This  parameter equals the smallest number of edges that must be removed in order to ensure that the  order  of  each  component  of  the  resulting  sub -network  or  sub-graph  is  less than k.

Innovation potentials and innovative networks in European metropolitan regions: Some empirical evidence from the Metropolitan Area of Barcelona

Innovation potentials and innovative networks in European metropolitan regions - some empirical evidence from the Metropolitan Area of Barcelone Revilla Diez, Javier; Escorsa, Pere and Camacho, Jaime Alberto Interregional competitiveness and the relationship between technology and competitiveness has increasingly become the object of considerable interest. The stimulation of innovation potentials within a region is becoming more and more decisive in the competition between regions. Although a precise definition of the term innovation potential is difficult, there is no doubt that it is essentially the stock of knowledge and its use which makes up the innovation potential of a region. This stock, however, is an inert factor. Its conversion into innovation underlines the importance of linkages and relationships in everyday innovation processes. Firms pursue co-operative agreements in order to gain rapid access to new technologies or new markets, to benefit from economies of scale in joint R&D and production to tap into essential resources of know-how and to share risks. These linkages possess a number of features which make the network mode a distinct from inter-firm organisation. This paper attempts to give a clear documentation of current innovation activities in the metropolitan region of Barcelone between the three major actors in innovations systems: industrial firms, producer services and research institutions. The presented results are based on representative surveys within an international comparative study in three major metropolitan areas in Europe (Barcelone, Stockholm and Vienna). The results of this research will be relevant for an understanding of how and why different industries build cooperative relationships in metropolitan regions. The results will also provide insights for policy efforts that can help to nurture and expand the regional economic base in the face of the current rapid globalisation of production. Keywords: Innovation potential, Innovation networks, Metropolitan regions, Barcelona