Financial requirements for nationwide fibre access coverage

It is common knowledge that Next Generation Access (NGA) networks require significant investments and that for many regions, especially in more rural areas, there is no viable business case. Taking note of the broadband strategies formulated by European governments the deployment cost is analysed to assess options for extending the profitable coverage of FTTH. In this paper a bottom-up cost model is applied to determine the investment and cost of deploying and operating a FTTH network in Germany on a national level. The monthly cost per subscriber at rising penetration is compared with the Average Revenue Per User (ARPU) to determine the required penetration level or the required revenue for profitable operation in a steady market state. Those regions for which there is no business case are analysed with regard to the level of required subsidies. All modelling is based on differentiated geotypes reflecting urban and rural areas. The basic cost model used has been applied to numerous case studies before and was adapted to determine different forms of subsidies. The research questions addressed are. What is the limit of profitable FTTH coverage in Germany? What is the level of prices, internal subsidisation or investment subsidy necessary to increase the coverage of FTTH in Germany? These results inform policy makers and operators of the relevant investment deltas and/or price levels needed to increase the coverage of next generation broadband access infrastructure. --Next Generation Access,FTTH,cost modelling,GPON,P2P,broadband strategy

Modelling the impact of Next Generation Access (NGA) on voice termination cost

Termination of a telephone call can only be realized by the network operator of the receiving party. For this reason, the markets for fixed and mobile call termination are regulated ex-ante including price control. To determine the costs of call termination the current regulatory regime considers only those parts of the network where customers compete for jointly used resources (mainly bandwidth). Therefore, the critical border is the "demarcation point" between the end customer dedicated access network and the aggregation network where customers compete for bandwidth. In addition to the extent of the overall network cost to be considered (depending on the location of the demarcation point) the traffic share of the voice termination service (which determines how much of the relevant cost is borne by voice termination) compared to all the other services sharing the same NGN/ NGA network needs to be taken into account. We analyse the cost effects with a cost model, which considers the part of the access network from the MPoP to the demarcation point, where the dedicated (access) network begins, in detail. This allows us to compare the impact of different demarcation points and service scenarios on the level of voice termination rates for three NGA architectures (FTTH/P2P, FTTH/PON and FTTC). We considered double and triple play service packages and ran sensitivities on data usage. In addition, we calculated termination cost for three different demarcation point locations in the case of FTTH/PON. --Voice Termination,Next Generation Access,FTTH,price regulation,termination monopoly,cost modelling

Critical market shares for investors and access seekers and competitive models in fibre networks

In this paper we consider and evaluate NGA architectures which meet the foreseeable future bandwidth demand and allow for highest bandwidth and quality for end-users and which no longer rely on copper cable elements. These are FTTH architectures only. From all available FTTH architectures we concentrate on the two most relevant architectures in Europe, Ethernet Point-to-Point and GPON. We assume the incumbent to be the investor in the NGA network infrastructure. If the NGA architecture is based on a Point-to-Point fibre plant we have modelled the competitors as using unbundled fibre loops as the wholesale access service. If the architecture is based on a Point-to-Multipoint fibre plant, we consider an active wholesale access (bitstream access) at the MPoP or at the core network node locations. Our basic modelling relies upon an engineering bottom-up cost modelling approach. We model the total cost of the services considered under efficient conditions, taking into account the cost of all network elements needed to produce these services in the specific architecture deployed. This approach is coherent with a Long Run Incremental Cost approach as applied in regulatory economics. Our modelling approach generates a broad set of results including the relative performance of the various network architectures, investment requirements and the degree of profitable coverage. In this paper, however, we focus on the results on the potential for competition and potential market structures in an NGA environment. --NGA architecture,cost modelling,FTTH,coverage,access models,unbundling

Generally covariant quantum information

The formalism of covariant quantum theory, introduced by Reisenberger and Rovelli, casts the description of quantum states and evolution into a framework compatible with the principles of general relativity. The leap to this covariant formalism, however, outstripped the standard interpretation used to connect quantum theory to experimental predictions, leaving the predictions of the theory ambiguous. In particular, the absence of a pre-defined time variable or background causal structure resulted in an ``order of projections ambiguity, in which the usual rule for multiple-measurement probabilities (obtained by time-ordered projections) is not defined. Equally troublesome, the probability postulate of Reisenberger and Rovelli fails to reproduce the Born interpretation for the case of simple quantum mechanical systems. Here, we develop an alternative quantum measurement formalism, based on basic principles of quantum information. After reviewing how this can be done in the context of the traditional formulation of quantum mechanics and noting its implications for the quantum measurement problem, we find that this approach can be generalized to the covariant setting, where it essentially solves the correspondence problems of covariant quantum theory. We show explicit agreement with the Born interpretation of standard quantum mechanics in the context of simple systems. We also demonstrate the origin of the quantum mechanical arrow of time within our framework, and use this to solve the order of projections ambiguity. In addition to compatibility with general covariance, we show that our framework has other attractive and satisfying features - it is fully unitary, realist, and self-contained. The full unitarity of the formalism in the presence of measurements allows us to invoke time-reversal symmetry to obtain new predictions closely related to the quantum Zeno effect

The State of Sustainable Research Software: Results from the Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE5.1)

This article summarizes motivations, organization, and activities of the Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE5.1) held in Manchester, UK in September 2017. The WSSSPE series promotes sustainable research software by positively impacting principles and best practices, careers, learning, and credit. This article discusses the Code of Conduct, idea papers, position papers, experience papers, demos, and lightning talks presented during the workshop. The main part of the article discusses the speed-blogging groups that formed during the meeting, along with the outputs of those sessions

Pointing acquisition and stabilization test bed

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaf 84).by Stephan Jay Feldgoise.M.S

An improved quantitative measure of the tendency for volcanic ash plumes to form in water: implications for the deposition of marine ash beds

Laboratory experiments and numerical simulations have shown that volcanic ash particles immersed in water can either settle slowly and individually, or rapidly and collectively as particle-laden plumes. The ratio of timescales for individual and collective settling, in the form of analytical expressions, provides a dimensionless quantitative measure of the tendency for such plumes to grow and persist which has important implications for determining particle residence times and deposition rates. However, existing measures in the literature assume that collective settling obeys Stokes' law and is therefore controlled by the balance between gravitational forces and viscous drag, despite plume development actually being controlled by the balance between gravitational forces and inertial drag even in the absence of turbulence during early times. This paper presents a new measure for plume onset which takes into account the inertial drag-controlled (rather than viscous drag-controlled) nature of plume growth and descent. A parameter study comprising a set of numerical simulations of small-scale volcanic ash particle settling experiments highlights the effectiveness of the new measure and, by comparison with an existing measure in the literature, also demonstrates that the timescale of collective settling is grossly under-estimated when assuming that plume development is slowed by viscous drag. Furthermore, the formulation of the new measure means that the tendency for plumes to form can be estimated from the thickness and concentration of the final deposit; the magnitude and duration of particle flux across the water's surface do not need to be known. The measure therefore permits the residence times of particles in a large body of water to be more accurately and practically determined, and allows the improved interpretation of layers of volcaniclastic material deposited at the seabed