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We consider the two-level uncapacitated facility location problem with single-assignment constraints (TUFLP-S), a problem that arises in industrial applications in freight transportation and telecommunications. We present a new Lagrangian relaxation [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jdeveco.2009.09.012 Byline: Farid Gasmi (a), Laura Recuero Virto (b) Keywords: Telecommunications; reforms; institutional risk; financial constraints; developing countries Abstract: This paper has two related objectives. First, it seeks to identify the key determinants of some policies that have been at the heart of the reforms of the telecommunications industry in developing countries, namely, liberalization, privatization, and the (re)structuring of regulation. Second, it attempts to estimate the extent to which these policies have translated into actual deployment of telecommunications infrastructure. This simultaneous investigation is conducted by means of an econometric analysis of a 1985-1999 time-series-cross-sectional database on 86 developing countries. Sectoral as well as institutional and financial factors are found to be important determinants of the actual reforms implemented. We uncover a positive relationship between the decision to introduce competition in the digital cellular segment and the growth of the fixed-line segment, suggesting that these two segments have benefited from each other. We also find that countries facing increasing institutional risk and financial constraints are more likely to introduce competition in the digital cellular segment and to privatize the fixed-line incumbent, these policies being economically attractive to both investors and governments. In turn, these policies are those that enhance the deployment of fixed-line infrastructure. In contrast, competition in the analogue cellular segment and the creation of a separate regulator seem to be relatively less attractive policies as they are found to be less likely to be introduced in countries facing increasing institutional risk and budget constraints. Their impact on fixed network deployment is found to be negative or non significant. Author Affiliation: (a) Toulouse School of Economics (ARQADE & IDEI), Universite Toulouse 1 Capitole, France (b) Organisation for Economic Co-operation and Development, France Article History: Received 19 July 2008; Revised 26 September 2009; Accepted 30 September 2009 Article Note: (footnote) [star] An earlier version of this paper was presented at the ASSET meeting, Padua, Italy, November 2007, the ADRES meeting, Toulouse, France, January 2008, the meeting of the Royal Economic Society, University College of London, UK, January 2008, and the ISNIE meeting, Toronto, Canada, June 2008. We thank participants to these events for useful comments. We are indebted to E. Auriol, L.H. Gutierrez, R. McNary, R. Rathindran, S. Wallsten, and L.C. Xu for their help in the construction of the database used in this paper, and to D. Filmer for providing some software. We thank T. Magnac, M. Traore, the editor of this journal, and two anonymous referees for useful comments. Supplemental material to this paper is available from the authors upon request. All remaining errors are ours only, however.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.worlddev.2008.12.005 Byline: Philip N. Howard Keywords: digital divide; internet; mobile phones; policy reform; time-series cross-sectional analysis; developing countries Abstract: How do telecommunications policies influence technology adoption? Has regulatory reform helped mitigate or exacerbate the digital divide? We examine the effects of four policy reform strategies on a country's share of internet bandwidth, internet hosts, internet users, personal computers, and mobile phones. We argue that the best policy environment for the telecommunications sector is one maintained by an independent regulator that is not above representing the public interest or entering into public private partnerships to develop national information infrastructure. Holding other factors constant, privatizing the national telecommunications operator only has a few demonstrable effects, and the effects are mixed. Liberalizing the market for consumer communications services and separating the telecommunications regulator from direct control by the executive branch of government are, for the most part, constructive policies for encouraging technology adoption. Yet over time, too little public policy oversight usually has a negative impact on technology adoption. Regulatory independence mitigates against the digital divide, but regulatory withdrawal exacerbates it. Our findings offer greater coverage than prior research, and emerge from a time-series cross-sectional study of multiple technology indicators in 154 countries during the period 1990-2007. Author Affiliation: University of Washington, United States Center for Advanced Study in the Behavioral Sciences, United States Article History: Accepted 22 December 2008

This paper assesses the growth impact of telecommunications infrastructure investment in developing countries by subjecting country specific data on mainline tele-density and per capita growth to Granger causality test within a panel co-integration framework. The results suggest that growth effects vary widely across country groupings reflecting different levels of development. Mainline tele-density and per capita growth strongly reinforces each other for countries that are relatively less developed. In contrast, there is, at best, a weak evidence of a bi-directional causal link between the two variables for countries that are relatively more industrialized. These differences in mainline tele-density and per capita growth relationship suggest that investment in telecommunications infrastructure, with its potential to generate high growth return, may serve as the central engine for driving the development process forward in the less developed countries. Keywords: Developing Countries, Telecommunications Infrastructure, Spillover Network Effects, development gap, growth convergence, Per Capita Growth, Mainline Tele-density, Co integration, Causality, 1. INTRODUCTION Asymmetry in per capita income growth has always been a major concern in the growth theoretic literature. Consequently, a key question that often intrigued economists is whether there [...]

The article discusses the benefits, advantages and the shortcomings of several new converged technologies that are being used in the communications world. The converged technologies are shown to be extremely efficient, as they provide unrestricted services and information to the customers.

A fast and numerically robust implementation of the Data Projection Method (DPM) is developed for adaptively estimating and tracking subspaces. This scheme consists of the numerically stable, low complexity algorithm for tracking subspaces corresponding to the smallest singular vales.

We describe the development of fast heuristics and methodologies for congestion minimization problems in directional wireless networks, and we compare their performance with optimal solutions. The focus is on the network layer topology control problem (NLTCP) defined by selecting an optimal ring topology as well as the flows on it. Solutions to NLTCP need to be computed in near realtime due to changing weather and other transient conditions and which generally preclude traditional optimization strategies. Using a mixed-integer linear programming formulation, we present both new constraints for this problem and fast heuristics to solve it. The new constraints are used to increase the lower bound from the linear programming relaxation and hence speed up the solution of the optimization problem by branch and bound. The upper and lower bounds for the optimal objective function to the mixed integer problem then serve to evaluate new node-swapping heuristics which we also present. Through a series of tests on different sized networks with different traffic demands, we show that our new heuristics achieve within about 0.5% of the optimal value within seconds. doi: 10.1057/palgrave.jors.2602360 Keywords: telecommunications; optimization; heuristics

Open shortest path first (OSPF) is the most widely used intra-domain Internet routing protocol. The OSPF protocol directs the Internet traffic along the shortest paths that are defined by the links weight. Traffic engineering is responsible for improving the network performance, for instance, the objective function that minimizes the maximal link utilization which is usually adopted to avoid the network congestion. This paper formulates the model of OSPF routing, and further evaluates the performance of different approaches. We also propose a heuristic algorithm to solve the routing problems by optimizing OSPF weights. Computational results indicated that the proposed algorithm could lead to good load balancing, and make efficient utilization of network resources. Keywords: Heuristic; Optimization; Routing; Telecommunication, 1. Introduction The major advantage of the transmission control protocol and Internet protocol (TCP/IP) is to permit diverse types of physical networks to be tied together so that any computer [...]

As high-speed networks have proliferated across the globe, their topologies have become sparser due to the increased reliability of components and cost considerations. Reliability has been a traditional goal within network design optimization. An alternative design consideration, network resilience, has not been studied or incorporated into network designs nearly as much. The authors propose a methodology for the difficult estimation of traffic efficiency (TE), a measure of network resilience, and a hybrid genetic algorithm to design networks using this measure. Keywords: Telecommunications; Reliability; Simulation; Stochastic programming, 1. Introduction Functions of a telecommunication network backbone are so vital that component failure scenarios must be considered during design, especially for sparse fiber optic networks. Therefore, the design of [...]

Given the pervasive nature of computer and communication networks, many paradigms have been used to study their properties and performances. In particular, reliability models based on topological properties can adequately represent the network capacity to survive failures of its components. Classical reliability models are based on the existence of end-to-end paths between network nodes, not taking into account the length of these paths; for many applications, this is inadequate, because the connection will only be established or attain the required quality if the distance between the connecting nodes does not exceed a given value. An alternative topological reliability model is the diameter-constrained reliability of a network; this measure considers not only the underlying topology, but also imposes a bound on the diameter, which is the maximum distance between the nodes of the network. In this work, we study in particular the case where we want to model the connection between a source-vertex s and a set of terminal vertices K (for example, a video multicast application), using a directed graph (digraph) for representing the topology of the network with node set V. If the s, K-diameter is the maximum distance between s and any of vertices of K, the diameter-constrained s, K-terminal reliability of a network G, Rs, K(G, D), is defined as the probability that surviving arcs span a subgraph whose s, K-diameter does not exceed D. One of the tools successfully employed in the study of classical reliability models is the domination of a graph, which was introduced by Satyanarayana and Prabhakar. In this paper we introduce a definition and a full characterization of the domination in the case of the diameter-constrained s, K-terminal reliability when K = V, including the classical source-to-all-terminal reliability domination result as a specific case. Moreover we use these results to present an algorithm for the evaluation of the diameter-constrained s, V-terminal reliability [R.sub.s,V] (G, D). Keywords: Reliability; Networks; Diameter; Domination, 1. Introduction The components of a communication network (e.g. nodes, communication links) may be subject to random failures. Failures may arise from natural catastrophes (e.g. hurricanes), component wear-out, or action [...]

In wide code-division multiple access (WCDMA), data transfer to a group may either take place on multiple point-to-point (PTP) channels transmitted to individual group members separately or on a single point-to-multipoint (PTM) channel that is broadcast over the entire cell. We evaluate the capacity of three channel selection strategies for one-to-many multicast over the WCDMA air interface in terms of outage probability. With the first scheme, dedicated or PTP traffic channels carry multicast data to individual users, whereas the second scheme relies on a single common or PTM channel for broadcasting multicast data within the entire cell. The third scheme finally combines the PTP and PTM approaches by transmitting a single PTM channel over the cell center while transmitting PTP channels to multicast users close to the cell boundary, allowing these users to benefit from macrodiversity gain and, in doing so, improving handover performance. We study the capacity of each of the three schemes by first deriving suitable outage probability expressions and then calculating the overall capacity, i.e., the number of multicast users that can be supported by each of the three schemes. Our comparative study gives insight into the tradeoffs between the three schemes under varying system parameters. Index Terms--Capacity, multicast, outage probability, universal mobile telecommunications system (UMTS), wide code-division multiple access (WCDMA).

What do citizens need from the media, and how should this be regulated? Western democracies are witnessing a changing regulatory regime, from 'command-and-control' government to discursive, multistakeholder governance. In the United Kingdom, the Office of Communications (Ofcom) is required to further the interests of citizens and consumers, which it does in part by aligning them as the citizen-consumer. What is meant by this term, and whether it captures the needs of citizens or subordinates them to those of consumers, has been contested by civil society groups as well as occasioning some soul-searching within the regulator. By triangulating a discursive analysis of the Communications Act 2003, key actor interviews with the regulator and civil society bodies, and focus groups among the public, the authors seek to understand how these terms ('citizen,' 'consumer,' and 'citizen-consumer') are used to promote stakeholder interests in the media and communications sector, not always to the benefit of citizens. Keywords: citizen interests; consumer representation; media and communications regulation; civil society; public understanding of regulation

Abstract--In IETF RFC 2002, Mobile-IP was developed to enable Laptobs to maintain Internet connectivity while moving between subnets. However, the packet loss that comes from switching subnets arises because network [...]

A study is conducted on regulatory interventions in telecommunications markets to emphasize on the merits of investments in network assets.

A study is conducted on a regulatory frame implemented by European Union to analyze the importance of long term investments in electronic communications sector.

With an increased level of interconnection between critical network infrastructures, the potential for cascading actions that trigger both primary and secondary network failures are of great concern. Recent events, including the 2001 attacks on the World Trade Center, the blackout of 14 August 2003, and the Galaxy IV satellite failure in 1998, have reinforced the need for a more thorough understanding of vulnerabilities relative to system performance. This article explores the topological complexities associated with network interconnections. In particular, we evaluate the potential impacts of losing critical infrastructure elements that are geographically linked. The loss of vital nodes, like telecommunication switching centers, is evaluated utilizing a developed spatial optimization model. Results indicate that certain infrastructure topologies are not particularly well equipped to handle the loss of vital nodes, whereas others could withstand the loss of such nodes and maintain an adequate level of service. Key Words: critical infrastructure, spatial analysis, reliability, telecommunication.

A study analyzing the advantages of using information and communication technology for eradicating poverty, and giving access to basic healthcare and education in developing countries is presented. A comparative analysis of growth is also presented based on the criterion of Internet usage by the countries.

Innovations in the field of electronics, telecommunications and information technology has created a digital economy, thus being responsible for a very progressive world but the progress was interrupted by the collapse of the dot com bubble, which highlighted the drawbacks of the new technologies. In the future, it is necessary to identify and facilitate breakthrough technologies, develop these technologies, design development friendly policies and maintain the right to intellectual property and prevent piracy.

The problematic real-work applications of low-density parity-check (LDPC) codes are discussed. A joint (3,k)-regular LDPC code and decoder/encoder design technique, to construct a class of (3,k)-regular LDPC codes, is presented.

Canada, South Korea, Netherlands and Sweden have seeked to create a regulatory environment for an effective competition in communication. A survey of these four countries was conducted to identity the lead markets converging in communication service.

The design of vector quantizers for diversity-based communication over two or more channels of possibly differing capacities and failure probabilities, is considered. The crucial dependence of current design techniques on initialization, especially of index assignment, is well recognized. Instead, we propose to pursue a deterministic annealing approach which is independent of initialization, does not assume any prior knowledge of the source density, and avoids many poor local minima of the cost surface. The approach consists of iterative optimization of a random encoder at gradually decreasing levels of randomness as measured by the Shannon entropy. At the limit of zero entropy, a hard multiple description (MD) quantizer is obtained. This process is directly analogous to annealing processes in statistical physics. Via an alternative derivation, we show that it may also be interpreted as approximating the minimum rate sums among points on the convex hull of the MD achievable rate-distortion region of El Gamal and Cover, subject to constraints on the sizes of the reproduction alphabets. To illustrate the potential of our approach, we present simulation results that show substantial performance gains over existing design techniques. Index Terms--Deterministic annealing, multiple descriptions, quantization, source coding, vector quantization.

A first national private telecommunications industry Ombudsman (TIO) is introduced in 1993 by Australia. The role of TIO as a mechanism for dispute resolution and as an industry regulator is examined.

The commercial space sector- and telecommunications in particular - is strong and growing, to the extent that rules are now needed to regulate trade in new products and services. However, the inclusion of space services within the remit of the WTO may not currently be in the interests of the industry. The WTO regime is presently too rigid and tends to 'judicialize' business rather than taking a political approach. Using telecommunications as an example, it is argued that a more flexible means of regulating the commercial space sector must be sought.

The sustainability of telecommunication industry in a competitive liberalization environment depends on its protection through easy access and strengthening of the service institutions. An alternative to the conventional system is the use of wireless communication, which allows broad-based access. Wireless access offers scalability, low cost and appropriate architecture for the sustenance of telecommunication sector including individual service providers.

Electronic communication among spatially distributed individuals has a strong impact on society and culture. Electronic communication leads to phenomena such as clustering of social groups, correlation among unrelated issues, consolidation of minorities, and continuing diversity. Social influence is a function of strength, immediacy, and number of sources of influence in a situation. Through changes in communication channels, organizations influence opinion diversity to sustain a common culture. The adoption of hierarchical geometry by neural networks helps develop minority and majority perspectives.

Deutsche Telekom had fallen behind in digitalizing its local telephone switching operations during the 1980s. Advances in technology and the reunification of Germany presented an opportunity for Deutsche Telekom to begin a large-scale fiber in the loop network. The large installation base will create a sufficient number of linked sites to encourage the telecommunications industry to invest in new products.

Multimedia services are made possible by a host of underlying technologies. These include the processing of speech, audio, image and video signals, and handwritten data, as well as the high-quality transmission of audiovisual messages and data information. Audiovisual signal processing incorporates the subtechnologies of coding, synthesis, and recognition, and the technologies that support acoustical and optical transducers. Synchronous processing of component signals in real time is a particularly important challenge. The communication technologies used to transmit multimedia services include wired and wireless modems, circuit-switched and packet-switched networks, and technologies such as simultaneous voice and data for seamless integration of multimedia messages. All these technologies depend, for their efficiency and pervasiveness, on the low-cost processing power provided by submicron very large-scale integration (VLSI). This paper describes the current capabilities in these technologies and the future challenges, in terms of quantitative metrics and tradeoffs.

An assessment has been made on the possible collusion among the regional Bell operating companies should the Modifications of Final Judgment (MFJ) restrictions be lifted. Such possibility was found quite unlikely when the competitiveness of three various markets adjacent to the local telephone exchange was examined. Since the AT&T divestiture in 1984, the Baby Bells have been competing against each other vigorously. Regulatory and market changes also indicate that the RBOCs will not engage in cross-subsidization or foreclosure.

The recent standardization of the Synchronous Optical Network (SONET) technology opens up new opportunities for integrating survivability into the telecommunications network planning process. Survivability has become in important element of network planning due to the business community's increasing reliance on telecommunications networks for various transactions, including funds transfer, inventory control, order processing and customer service. With the introduction of the SONET technology and associate high-speed add/drop multiplexing, a ring structure has come to be the architecture of choice for designing survival networks. A clustering problem for designing logical SONET rings is considered, for which a heuristic solution based on the tabu search framework is formulated.