Connectivity measures for internet topologies on the level of autonomous systems

Classical measures of network connectivity are the number of disjoint paths between a pair of nodes and the size of a minimum cut. For standard graphs, these measures can be computed efficiently using network flow techniques. However, in the Internet on the level of autonomous systems (ASs), referred to as AS-level Internet, routing policies impose restrictions on the paths that traffic can take in the network. These restrictions can be captured by the valley-free path model, which assumes a special directed graph model in which edge types represent relationships between ASs. We consider the adaptation of the classical connectivity measures to the valley-free path model, where it is -hard to compute them. Our first main contribution consists of presenting algorithms for the computation of disjoint paths, and minimum cuts, in the valley-free path model. These algorithms are useful for ASs that want to evaluate different options for selecting upstream providers to improve the robustness of their connection to the Internet. Our second main contribution is an experimental evaluation of our algorithms on four types of directed graph models of the AS-level Internet produced by different inference algorithms. Most importantly, the evaluation shows that our algorithms are able to compute optimal solutions to instances of realistic size of the connectivity problems in the valley-free path model in reasonable time. Furthermore, our experimental results provide information about the characteristics of the directed graph models of the AS-level Internet produced by different inference algorithms. It turns out that (i) we can quantify the difference between the undirected AS-level topology and the directed graph models with respect to fundamental connectivity measures, and (ii) the different inference algorithms yield topologies that are similar with respect to connectivity and are different with respect to the types of paths that exist between pairs of ASs.

Taking the brand promise online: challenges and opportunities

Starting from the fact that a 'brand' is a universal concept regardless of environment, but its enactment changes according to environment, this paper provides pointers about brand building on the internet. It presents a three-level model of a brand to help organisations characterise their brands' promises. By expanding this model it then considers how a brand's promise can be enacted on the internet in order to assess the coherence of the brand. Through considering how some organisations have taken advantage of the internet, it highlights three factors critical for success. Ten key action points for marketers are presented.

Entrepreneurial opportunities, implicit contracts and market making for complex consumer goods

This article extends the theory of entrepreneurial opportunity exploitation, outlining how under certain conditions, opportunity exploitation is dependent on market making innovations. Where adverse selection and moral hazard characterize markets, consumers are likely to withdraw regardless of product quality. In order to overcome consumer resistance, entrepreneurs must signal credible commitments. But because consumers purchase without fully specifying requirements, entrepreneurs' commitments take the partial form of implicit contracts, creating strong mutual commitments to repeated transactions. These commitments enable novel markets to function, but introduce additional costs. This article illustrates the theory with the historic case of Singer in sewing machines

On the evolution of monopoly pricing in Internet-assisted search markets

This study examines the evolution of prices in markets with Internet price-comparison search engines. The empirical study analyzes laboratory data of prices available to informed consumers, for two industry sizes and two conditions on the sample (complete and incomplete). Distributions are typically bimodal. One of the two modes of distribution, corresponding to monopoly pricing, tends to attract such pricing strategies increasingly over time. The second one, corresponding to interior pricing, follows a decreasing trend. Monopoly pricing can serve as a means of insurance against more competitive (but riskier) behavior. In fact, experimental subjects who initially earn low profits due to interior pricing are more likely to switch to monopoly pricing than subjects who experience good returns from the start.

Remote Spectroscopy in the Visible Using Fibers on the Optical Internet Network

The work presented here demonstrates the feasibility of using the single-mode fibers of an optical Internet network to deliver visible light between separate laboratories as a way to perform remote spectroscopy in the visible for teaching purposes. The coupling of a broadband light source into the single-mode fiber (SMF) and the characterization of optical losses as a function of the wavelength are discussed. Sample spectra were measured with a portable spectrometer controlled by an acquisition program developed with the LabVIEW software that allows the data to be collected and analyzed.

Investment opportunities and leverage: some Australian evidence on the role of board monitoring and director equity ownership

This paper tests the hypothesis that the negative relationship between investment opportunity set (IOS) and debt is moderated by board monitoring and director equity ownership. According to contracting theory, firms with high growth opportunities (high IOS) are associated with lower levels of debt as a result of the asset substitution and the under-investment problem. However, our hypotheses test the conjecture that the negative debt / IOS relationship will be moderated by the proportion of non-executive directors (NEDs) on the board and director equity ownership. NEDs provide higher monitoring which reduces management discretion while director equity ownership provides incentives for managers to maximize the value of the firm. More specifically, we expect that high growth firms with a higher proportion of non-executive directors and director equity ownership are less likely to be associated with asset substitution and under investment. Thus, the negative investment opportunity set / debt relationship will be weaker for firms with higher levels of non-executive directors and high director equity ownership. Data collected from Australian companies support both these two hypotheses. Results have significant implications for corporate finance theory.

The internet and competitive advantage : a study of Australia`s four premier professional sporting leagues

Sport and the Internet have shown early signs of a prosperous marriage. Web sites with sport content are among the most popular and well trafficked, with sport followers and web users sharing remarkably similar demographics. In the United States, the sport–Internet union is projected to generate US$6.27 billion in advertising revenue alone on sports-related web sites by 2005. Despite these compelling observations, limited empirical research has been undertaken exploring how to maximise the opportunities for competitive advantage that the Internet can provide to sport organisations. This research was a response to this void, and was undertaken in three stages. Initially, empirical and conceptual Internet literature was reviewed to establish theoretical “best practice”. Secondly, the Internet goals, strategies and practices of the 55 teams competing in the Australian Football League (AFL), National Basketball League (NBL), National Rugby League (NRL), and National Soccer League (NSL) were examined, using a telephone-administered survey. An 87% (N = 48) response rate was achieved. Finally, seven recommendations for closing this gap were made, including the implementation of Internet project teams and the instigation of league forums.