André F. Gygax

Methodologies for assessing the use-phase power consumption and greenhouse gas emissions of telecommunications network services.

Internet traffic has grown rapidly in recent years and is expected to continue to expand significantly over the next decade. Consequently, the resulting greenhouse gas (GHG) emissions of telecommunications service-supporting infrastructures have become an important issue. In this study, we develop a set of models for assessing the use-phase power consumption and carbon dioxide emissions of telecom network services to help telecom providers gain a better understanding of the GHG emissions associated with the energy required for their networks and services. Due to the fact that measuring the power consumption and traffic in a telecom network is a challenging task, these models utilize different granularities of available network information. As the granularity of the network measurement information decreases, the corresponding models have the potential to produce larger estimation errors. Therefore, we examine the accuracy of these models under various network scenarios using two approaches: (i) a sensitivity analysis through simulations and (ii) a case study of a deployed network. Both approaches show that the accuracy of the models depends on the network size, the total amount of network service traffic (i.e., for the service under assessment), and the number of network nodes used to process the service.

Audit quality, auditor compensation and initial public offering underpricing

We jointly study the impact of audit quality on auditor compensation and initial public offering (IPO) underpricing using a sample of Australian firms going public over the period 1996-2003. We find that quality (Big Four) audit firms earn significantly higher fees than non-Big Four auditors, and audit quality is positively associated with IPO underpricing. The positive relation between audit quality and underpricing is more pronounced for small issues, IPOs underwritten by non-prestigious underwriters, and those that are not backed by venture capitalists. Taken together, our results suggest that quality auditors serve as a signalling device that enhances post-issue market value of equity.

Assessing network energy consumption of mobile applications

Continuous growth in the energy consumption of mobile networks has become a major concern for mobile carriers. Since current mobile networks are dominated by mobile data traffic generated by over-the-top mobile applications, it is crucial for mobile carriers to understand how much network energy is used to deliver these applications. Here, we use real network and application measurements to comprehensively analyze the energy consumption of 12 common mobile applications by breaking down their total energy consumption into data and signaling energy components. The results provide insights into the different proportions of data and signaling energy (due to LTE signaling) for different mobile applications. They show that the energy consumption of a mobile application can vary at different base station cell sites due to different ratios of throughput to physical resource block utilization. We estimate the total monthly energy consumption of all 4G users of a major mobile carrier using conventional mobile services, such as voice and the short messaging service, and two over-the-top applications, i.e. a popular instant messaging application in China and an online video application. The results show that signaling energy consumption may become a major concern for mobile carriers, and that this issue will be exacerbated as the usage of over-the-top applications continues to grow. Energy assessment of mobile applications provides valuable information to enable mobile carriers to improve the energy efficiency of their networks. An energy assessment tool that enables real-time network and service energy monitoring will also assist in developing energy-efficient network policies for diverse applications with different energy consumption profiles. Furthermore, given our signaling energy consumption findings for over-the-top applications, there may be benefits for mobile operators to introduce a surcharge for signaling traffic to mitigate the high signaling energy consumption of some over-the-top mobile applications.

Energy efficiency of on-demand video caching systems and user behavior.

Energy-efficient video distribution systems have become an important tool to deal with the rapid growth in Internet video traffic and to maintain the environmental sustainability of the Internet. Due to the limitations in terms of energy-efficiency of the conventional server centric method for delivering video services to the end users, storing video contents closer to the end users could potentially achieve significant improvements in energy-efficiency. Because of dissimilarities in user behavior and limited cache sizes, caching systems should be designed according to the behavior of user communities. In this paper, several energy consumption models are presented to evaluate the energy savings of single-level caching and multi-level caching systems that support varying levels of similarity in user behavior. The results show that single level caching systems can achieve high energy savings for communities with high similarity in user behavior. In contrast, when user behavior is dissimilar, multi-level caching systems should be used to increase the energy efficiency.

How Eventful are Event Studies

This paper reexamines the event study methodology in finance. We consider a formal specification of an event study in terms of a system of abnormal returns and, in particular, emphasise the possible limitations of using a methodology when misspecification may be present. In the first section of the paper, the theory of the event study is reviewed, with reference to the definition problems associated with the measurement of abnormal returns, the conditional information set embedded in return expectations, the determination of the event window, and the similarity across events. A major insight of our paper is to emphasise the importance of conditionality, learning and convergence in the theory of event studies and in the evolution of abnormal returns. In one section of the paper, we look at the question of recursive residuals, residuals formed when the information set is updated period by period, and implicitly question why they have not been used in event studies. In another section, the focus is on the specification of learning models, both across events and within the event period. Furthermore, we provide some conjectures about how to measure the information in events. Finally, we bring together the issues into a coherent methodology.

What Do Investment Banks Truly Bring to the Table

This paper investigates the role of intermediaries in the initial public offering (IPO) process. In the U.S. market, investment banks have traditionally been involved in a firm-commitment or best-efforts underwriting capacity. However, in the Australian IPO market, investment banks are increasingly being named in association with new issues in diverse roles such as issue managers, sponsoring brokers and corporate advisers. Using a sample of 468 IPOs over the 1996 to mid-2006 period, we examine the influence of investment banks across these different engagements. In support of the signalling and information production roles of intermediaries, we find that issuers choosing high intermediary involvement are typically older, retain more capital, seek to raise larger amounts of capital and are without independent expert certification. We find mixed support for the certification hypothesis when testing for the effect of intermediary reputation on IPO issuer wealth loss. Further, the impact of intermediary involvement on underpricing is not significantly different for the different levels of intermediary involvement once issue characteristics have been accounted for. This is puzzling since these different roles by definition do not provide the same level of issue quality assurance.

Are Fat Cats Copycats? Evidence from Director and Consultant Network Dynamics

Prior literature identifies great similarity in executive compensation packages of firms and has succeeded in hypothesizing but not in substantiating the responsible channel or channels. We introduce dynamic stochastic network techniques to directly analyze the following three possible channels simultaneously for the first time: sharing directors, sharing compensation consultants, and sharing industry membership. Using the dynamic technology, we show that package similarity is achieved by sharing directors and industry membership rather than by sharing compensation consultants. Moreover, boards with fewer females are more likely to include higher proportions of options compensation, and higher fixed compensation deters tie formation.

Do Index Effects Reflect Idiosyncratic or Industry Effects? A Re-Examination of the Winners and Losers of S&P 500 Index Addition

This paper provides new findings concerning additions to the S&P 500 Index. We present the first evidence of industry effects that occur when stocks are added to the S&P 500 Index. With over a trillion dollars in index funds wealth tied to the S&P 500 Index, index additions exert price pressures on not only the firms that are added to the index and but the incumbent industry counterparts as well. We find that the share price of an added firms industry counterparts increase in the announcement date and decrease on the effective date. We provide evidence that portfolio rebalancing helps explain the effective date abnormal returns documented for the incumbent industry counterparts. In addition, we show that the likelihood of a company being added to the S&P 500 Index is higher in industries with strong innovative activity, making revisions to the Index a vehicle for incorporating the value of such activity. Overall, our results suggest that S&P 500 Index composition changes are not information-free events.

An Option Theory of Social Networks

This paper constructs a new theory of social networks based on the options individuals buy on each other. The model assumes that when an individual connects with another it is equivalent to buying options on the other’s reputation. The option model confers advantages not present in existing models. First, the payoff to connecting is endogenously determined by the reputation of the network. Secondly the strategy to connect is an option strategy. Thirdly, the network forms as individuals take option positions; the network evolves as individuals adjust those positions. The model allows for powerful insights into network structure, the price of connecting and the value of connecting.

Pedestrian behaviour analysis using the microsoft kinect

An important challenge for brick-and-mortar retail businesses is how to monitor the interest of customers in displays and products in a store. We investigate the effectiveness of the Microsoft Kinect as a sensor to monitor the behaviour of pedestrians, which may reflect their interest in a store display or advertisement. In a controlled environment, participants acting as pedestrians are requested to show different levels of interest as they pass an object that is being monitored by a Kinect sensor. The sensor collected measurements such as the positions and orientation of the pedestrians body and head, which were analysed to detect the movements of the pedestrians and thus infer the behaviour they exhibited. Our results demonstrate that when the Kinect is able to detect a behaviour that indicates a pedestrians interest in an object, then the classification of the level of interest in terms of the type of behaviour is reasonably accurate under varying light conditions and numbers of pedestrians.