Doctor of Philosophy

dissertationThis dissertation is composed of three essays which examine the effects of a firm's bankruptcy on its suppliers and customers. Suppliers and customers are considered to be stakeholders of the firm with which they trade and face potential costs if the firm files for Chapter 11. In the first essay, I examine the puzzle that while there is plenty of anecdotal evidence to show that upstream and downstream trading partners face costs when their trading partner is distressed, the existing literature seems to find that contagion effects are relatively small in magnitude. I propose and test a method which potentially reduces noise in the inputs used to determine wealth effects. I show that both suppliers and customers of filing firms experience significantly greater negative wealth effects due to the trading partner's distress than what has been documented in the existing literature. In the second essay, I examine the following question: how do supplier and customer stock price effects vary in the cross section when the trading partner becomes distressed and files for bankruptcy? I find evidence consistent with the hypothesis that the impact of the filing firm's distress on upstream and downstream firms depends on whether the bankrupt firm is economically distressed or financially distressed. The results show that both customers and suppliers of distressed firms face switching costs which vary significantly with the probability of successful reorganization of the filing firm, and these costs are higher when the degree of reliance and product specialization are greater. The third and final essay examines the trade credit policy of suppliers when their trading partner is distressed and files for Chapter 11. Trade credit is an economically important source of short-term funds for firms. I study empirically whether the data demonstrate that suppliers support customers in times of distress by continuing to extend credit or whether distressed customers are denied trade credit by suppliers who want to protect their own cash position. Evidence indicates that suppliers may continue to support their distressed customer by extending short-term credit depending on the probability of reorganization

Performance Evaluation of Distributed Security Protocols Using Discrete Event Simulation

The Border Gateway Protocol (BGP) that manages inter-domain routing on the Internet lacks security. Protective measures using public key cryptography introduce complexities and costs. To support authentication and other security functionality in large networks, we need public key infrastructures (PKIs). Protocols that distribute and validate certificates introduce additional complexities and costs. The certification path building algorithm that helps users establish trust on certificates in the distributed network environment is particularly complicated. Neither routing security nor PKI come for free. Prior to this work, the research study on performance issues of these large-scale distributed security systems was minimal. In this thesis, we evaluate the performance of BGP security protocols and PKI systems. We answer the questions about how the performance affects protocol behaviors and how we can improve the efficiency of these distributed protocols to bring them one step closer to reality. The complexity of the Internet makes an analytical approach difficult; and the scale of Internet makes empirical approaches also unworkable. Consequently, we take the approach of simulation. We have built the simulation frameworks to model a number of BGP security protocols and the PKI system. We have identified performance problems of Secure BGP (S-BGP), a primary BGP security protocol, and proposed and evaluated Signature Amortization (S-A) and Aggregated Path Authentication (APA) schemes that significantly improve efficiency of S-BGP without compromising security. We have also built a simulation framework for general PKI systems and evaluated certification path building algorithms, a critical part of establishing trust in Internet-scale PKI, and used this framework to improve algorithm performance

Monitoring and real-time simulation of an industrial production pipeline

Dissertação de mestrado integrado em Informatics EngineeringThere is a shortage of manufacturing management software solutions for businesses with various manual processes, and that offer a wide range of products. Existing solutions can become very expensive for small and medium-sized enterprises, and can discourage them to take the next step towards the 4th Industrial Revolution. This dissertation consists of joint work with Tipoprado, Artes Gráficas, to develop a package tracking and production performance analysis platform. The company has a notable number of different clients and offers different types of services. This way, different packages may go through different paths on the production pipeline. Given this, to offer a more close and customized service, Tipoprado, wants to develop a package tracking platform. This tracking is not geographical (delivery case), but about the package location over the production pipeline, giving clients the possibility to consult, in real-time, the actual state of their orders. Apart from this, implementing this platform produces a significant level of data about packages and clients. One of the main goals is to treat, process and analyze this data, to improve production efficiency and be able to help the its managers make crucial decisions about the referred pipeline. Production planning and predictions on delivery dates is the ultimate goal. This dissertation studies and implements the tracking method that best applies to Tipoprado production pipeline, together with data analysis, and prediction options. The given platform will transport the company to a tech production vision, and kick start its journey through the fourth industrial revolution. It is also expected to increase customer engagement levels, which correlate with a higher number of sales.Existe uma falta de soluções de software de gestão de manufatura para empresas com vários processos manuais, e que oferecem uma vasta gama de produtos. As soluções existentes podem-se tornar bastante dispendiosas para pequenas e médias empresas, e desencorajar as mesmas para dar o próximo passo em direção à 4a Revolução Industrial. Esta dissertação consiste num trabalho conjunto com Tipoprado, Artes Gráficas, para desen volver uma plataforma de tracking de encomendas e análise de desempenho de produção. A empresa possui um número notável de clientes diferentes e oferece diferentes tipos de serviços. Dessa forma, encomendas diferentes podem seguir caminhos diferentes na linha de produção. Dado isso, para oferecer um serviço mais próximo e personalizado, a Tipoprado, deseja desenvolver uma plataforma de tracking de encomendas. Esse tracking não é geográfico (caso de entrega), mas sobre a localização da encomenda no pipeline de produção, oferecendo aos clientes a possibilidade de consultar, em tempo real, o estado atual dos seus pedidos. Além disso, a implementação desta plataforma produz um nível significativo de dados sobre encomendas e clientes. Um dos principais objetivos é tratar, processar e analisar esses dados, melhorar a eficiência da produção e ajudar os responsáveis da empresa a tomar decisões cruciais sobre o referido pipeline. O planeamento da produção e as previsões nas datas de entrega é o objetivo final. Esta dissertação estuda e implementa o método de tracking que melhor se aplica à linha de produção da Tipoprado, junto com a análise de dados e opções de previsão. A plataforma fornecida transportará a empresa para uma visão de produção tecnológica e iniciará sua jornada na quarta revolução industrial. Também é esperado que aumente os níveis de envolvimento do cliente, que se correlacionam com um número maior de vendas

Inventory of ATT system requirements for elderly and disabled drivers and travellers

This Inventory of ATT System Requirements for Elderly and Disabled Drivers and Travellers is the product of the TELSCAN project’s Workpackage 3: Identification and Updating of User Requirements of Elderly and Disabled Travellers. It describes the methods and tools used to identify the needs of elderly and disabled (E&D) travellers. The result of this investigation is a summary of the requirements of elderly and disabled travellers using different modes of transport, including private cars, buses/trams, metros/trains, ships and airplanes. It provides a generic user requirements specification which can guide the design of all transport telematics systems. However, it is important to stress that projects should also capture a more detailed definition of user requirements for their specific application area or system

Hill of Banchory Geothermal Energy Project Feasibility Study Report

This feasibility study explored the potential for a deep geothermal heat project at Hill of Banchory, Aberdeenshire. The geology of the Hill of Fare, to the north of Banchory, gives cause to believe it has good geothermal potential, while the Hill of Banchory heat network, situated on the northern side of the town, offers a ready-made heat customer. The partners in the consortium consisted of academics and developers with relevant expertise in deep geothermal energy, heat networks, and financial analysis, together with representatives of local Government. They conducted geological fieldwork around the Hill of Fare, engaged with local residents to establish their attitudes to geothermal energy, and built business models to predict the conditions under which the heat network at Hill of Banchory would be commercial if it utilised heat from the proposed geothermal well. They also estimated the potential carbon emission reductions that could be achieved by using deep geothermal energy, both at Hill of Banchory and more widely

Greedy routing and virtual coordinates for future networks

At the core of the Internet, routers are continuously struggling with ever-growing routing and forwarding tables. Although hardware advances do accommodate such a growth, we anticipate new requirements e.g. in data-oriented networking where each content piece has to be referenced instead of hosts, such that current approaches relying on global information will not be viable anymore, no matter the hardware progress. In this thesis, we investigate greedy routing methods that can achieve similar routing performance as today but use much less resources and which rely on local information only. To this end, we add specially crafted name spaces to the network in which virtual coordinates represent the addressable entities. Our scheme enables participating routers to make forwarding decisions using only neighbourhood information, as the overarching pseudo-geometric name space structure already organizes and incorporates "vicinity" at a global level. A first challenge to the application of greedy routing on virtual coordinates to future networks is that of "routing dead-ends" that are local minima due to the difficulty of consistent coordinates attribution. In this context, we propose a routing recovery scheme based on a multi-resolution embedding of the network in low-dimensional Euclidean spaces. The recovery is performed by routing greedily on a blurrier view of the network. The different network detail-levels are obtained though the embedding of clustering-levels of the graph. When compared with higher-dimensional embeddings of a given network, our method shows a significant diminution of routing failures for similar header and control-state sizes. A second challenge to the application of virtual coordinates and greedy routing to future networks is the support of "customer-provider" as well as "peering" relationships between participants, resulting in a differentiated services environment. Although an application of greedy routing within such a setting would combine two very common fields of today's networking literature, such a scenario has, surprisingly, not been studied so far. In this context we propose two approaches to address this scenario. In a first approach we implement a path-vector protocol similar to that of BGP on top of a greedy embedding of the network. This allows each node to build a spatial map associated with each of its neighbours indicating the accessible regions. Routing is then performed through the use of a decision-tree classifier taking the destination coordinates as input. When applied on a real-world dataset (the CAIDA 2004 AS graph) we demonstrate an up to 40% compression ratio of the routing control information at the network's core as well as a computationally efficient decision process comparable to methods such as binary trees and tries. In a second approach, we take inspiration from consensus-finding in social sciences and transform the three-dimensional distance data structure (where the third dimension encodes the service differentiation) into a two-dimensional matrix on which classical embedding tools can be used. This transformation is achieved by agreeing on a set of constraints on the inter-node distances guaranteeing an administratively-correct greedy routing. The computed distances are also enhanced to encode multipath support. We demonstrate a good greedy routing performance as well as an above 90% satisfaction of multipath constraints when relying on the non-embedded obtained distances on synthetic datasets. As various embeddings of the consensus distances do not fully exploit their multipath potential, the use of compression techniques such as transform coding to approximate the obtained distance allows for better routing performances

The adoption of share-based compensation for executives in large German companies : the Americanisation of German executive pay?

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Three Essays on Corporate Disclosure and Information Externalities

This dissertation includes three essays on corporate disclosure and information externalities. In the first essay, I examine the disclosure behavior of rival firms identified by an Initial Public Offering (IPO) candidate during the IPO quiet period when the IPO candidate is restricted in its communication. I find that the tone of disclosures made by identified rivals becomes more positive during the quiet period, and reverses after the quiet period ends. The strategic disclosure behavior is mainly driven by identified rivals’ concerns over product market competition. I also find that this behavior hurts the IPO candidate and benefits the identified rivals. In the second essay, I investigate the relations between IPO firms’ peer choice and peer information environment. I find that IPO firms tend to select peer companies with a better information environment, and this effect is more pronounced for IPO firms with greater information uncertainties. I also find support that peer information environment is positively associated with upward offering price revision, post-offering analyst coverage, and negatively associated with the number of amendment filings. Overall, this essay shows that IPO firms can make use of the externalities of peer information to facilitate their initial public offerings. In the third essay, I switch my focus from intra-industry relations to supply chain relations. More specifically, I study the effects of layoff announcements by customers on the valuation and operating performance of their supply chain partners. I find that suppliers experience a negative stock price reaction around their major customers’ layoff announcements. The negative price effect is exacerbated when industry rivals of layoff-announcing customers also suffer from negative intra-industry contagion effects. Moreover, these supply chain spillover effects are asymmetric, with only “bad news” layoff announcements causing significant value implications for suppliers, but not “good news” announcements. Supplier firms also reduce their investment in and sales dependence on layoff-announcing customers in subsequent years. Keywords: Disclosure; Product market competition; IPO quiet period; Identified rivals; Information externalities; Peer information environment; Corporate layoffs, Supply chain relations; Stock market retur

Regulation and competition in German banking: an assessment

In Germany a public discussion on the "power of banks" has been going on for decades now with power having at least two meanings. On the one hand it is the power of banks to control public corporations through direct shareholdings or the exercise of proxy votes - this is the power of banks in corporate control. On the other hand it is market power - due to imperfect competition in markets for financial services - that banks exercise vis-à-vis their loan and deposit customers. In the past, bank regulation has often been blamed to undermine competition and the working of market forces in the financial industry for the sake of soundness and stability of financial services firms. This chapter tries to shed some light on the historical development and current state of bank regulation in Germany. In so doing it tries to embed the analysis of bank regulation into a more general industrial organisation framework. For every regulated industry, competition and regulation are deeply interrelated as most regulatory institutions - even if they do not explicitly address the competitiveness of the market - either affect market structure or conduct. This paper tries to uncover some of the specific relationships between monetary policy, government interference and bank regulation on the one hand and bank market structure and economic performance on the other. In so doing we hope to point to several areas for fruitful research in the future. While our focus is on Germany, some of the questions that we raise and some of our insights might also be applicable to banking systems elsewhere. Revised version forthcoming in "The German Financial System", edited by Jan P. Krahnen and Reinhard H. Schmidt, Oxford University Press

CHORUS Deliverable 2.2: Second report - identification of multi-disciplinary key issues for gap analysis toward EU multimedia search engines roadmap

After addressing the state-of-the-art during the first year of Chorus and establishing the existing landscape in multimedia search engines, we have identified and analyzed gaps within European research effort during our second year. In this period we focused on three directions, notably technological issues, user-centred issues and use-cases and socio- economic and legal aspects. These were assessed by two central studies: firstly, a concerted vision of functional breakdown of generic multimedia search engine, and secondly, a representative use-cases descriptions with the related discussion on requirement for technological challenges. Both studies have been carried out in cooperation and consultation with the community at large through EC concertation meetings (multimedia search engines cluster), several meetings with our Think-Tank, presentations in international conferences, and surveys addressed to EU projects coordinators as well as National initiatives coordinators. Based on the obtained feedback we identified two types of gaps, namely core technological gaps that involve research challenges, and “enablers”, which are not necessarily technical research challenges, but have impact on innovation progress. New socio-economic trends are presented as well as emerging legal challenges