Due to rising unemployment levels, researchers have begun to investigate how corporations handle layoffs and how they could manage them better in the future. Public relations practitioners can use this type of research to help organizations learn how to best maintain their images, reputations and productivity amid mass layoffs. When an organization conducts mass layoffs, its actions become both a current event and a public issue that is frequently discussed in newspaper articles. In order for downsizing organizations to be aware of the public?s perceptions of their layoff procedures, they should be aware of how the news media represents them. This study used a content analysis of different newspaper articles to determine how three downsizing organizations (General Motors, Caterpillar, and Boeing) were portrayed in the midst of mass layoffs. This study examined a sample of newspaper articles from two nationally-distributed daily newspapers (The New York Times and The Washington Post). It also included articles from daily newspaper that were located in the cities where the layoffs took place (The Detroit News, The Chicago Tribune, and The Seattle Times). The findings did not show that the newspapers? articles about the layoffs tended to be more prominent in the regional publications than in the national publications. While the articles were often prominently placed in the newspapers, the layoffs were not typically the primary focus of the articles. The reporters frequently included details of the layoffs, such as the number of layoff victims, in their articles. They also frequently included attributions of blame for the layoff decisions. The articles, however, rarely discussed socially responsible actions made on behalf of the downsizing companies.

本研究旨在探討管理當局自願性盈餘預測與權益資金成本之關聯性，檢視管理當局發布盈餘預測頻率之影響是否反應於權益資金成本上，並進一步檢視管理當局之聲譽是否為影響權益資金成本的因素之一。 在本研究的實證分析結果中，發現管理當局發布自願性盈餘預測之頻率與權益資金成本呈顯著負相關，表示管理當局發布盈餘預測的次數越多時，權益資金成本越低。 在管理當局聲譽對於權益資金成本的影響，本研究實證分析結果發現，管理當局之聲譽與權益資金成本亦呈顯著負相關，管理當局聲譽以管理當局預測誤差和分析師預測誤差來衡量，當管理當局的盈餘預測誤差小於分析師盈餘預測誤差時，投資人認為管理當局對盈餘的預測有效且值得信賴，此時管理當局聲譽提高，投資人認為取得有用的資訊，進而降低企業權益資金成本。 / The primary objective of this thesis is to explore whether the frequency of management forecasts is related to the cost of equity capital. In addition, I further examine whether the association is stronger when management has better reputation. Basing on a sample of S&P 500 listed firms during 2000-2009, I find that, consistent with my prediction, cost of firm’s equity capital decreases with the frequency of management earning forecasts after controlling for other determinants well-documented to be related to cost of equity capital. Second, I find that cost of equity capital is negatively related to the reputation of management; however, I do not find that the association between cost of equity capital and the frequency of management systematically vary with the reputation of management.

Mit der zunehmenden Verbreitung mobiler Endgeräte und Dienste ergeben sich auch neue Herausforderungen für ihre Sicherheit. Diese lassen sich nur teilweise mit herkömmlichen Sicherheitsparadigmen und -mechanismen meistern. Die Gründe hierfür sind in den veränderten Voraussetzungen durch die inhärenten Eigenschaften mobiler Systeme zu suchen. Die vorliegende Arbeit thematisiert am Beispiel von Wireless LANs die Entwicklung von Sicherheitsmechanismen für drahtlose Ad-hoc- und Infrastrukturnetze. Sie stellt dabei den umfassenden Schutz der einzelnen Endgeräte in den Vordergrund, die zur Kompensation fehlender infrastruktureller Sicherheitsmaßnahmen miteinander kooperieren. Den Ausgangspunkt der Arbeit bildet eine Analyse der Charakteristika mobiler Umgebungen, um grundlegende Anforderungen an eine Sicherheitslösung zu identifizieren. Anhand dieser werden existierende Lösungen bewertet und miteinander verglichen. Der so gewonnene Einblick in die Vor- und Nachteile präventiver, reaktiver und angriffstoleranter Mechanismen führt zu der Konzeption einer hybriden universellen Rahmenarchitektur zur Integration beliebiger Sicherheitsmechanismen in einem kooperativen Verbund. Die Validierung des Systementwurfs erfolgt anhand einer zweigeteilten prototypischen Implementierung. Den ersten Teil bildet die Realisierung eines verteilten Network Intrusion Detection Systems als Beispiel für einen Sicherheitsmechanismus. Hierzu wird eine Methodik beschrieben, um anomalie- und missbrauchserkennende Strategien auf beliebige Netzprotokolle anzuwenden. Die Machbarkeit des geschilderten Ansatzes wird am Beispiel von infrastrukturellem WLAN nach IEEE 802.11 demonstriert. Den zweiten Teil der Validierung bildet der Prototyp einer Kooperations-Middleware auf Basis von Peer-to-Peer-Technologien für die gemeinsame Angriffserkennung lose gekoppelter Endgeräte. Dieser kompensiert bisher fehlende Mechanismen zur optimierten Abbildung des Overlay-Netzes auf die physische Struktur drahtloser Netze, indem er nachträglich die räumliche Position mobiler Knoten in die Auswahl eines Kooperationspartners einbezieht. Die zusätzlich definierte Schnittstelle zu einem Vertrauensmanagementsystem ermöglicht die Etablierung von Vertrauensbeziehungen auf Kooperationsebene als wichtige Voraussetzung für den Einsatz in realen Umgebungen. Als Beispiel für ein Vertrauensmanagementsystem wird der Einsatz von Reputationssystemen zur Bewertung der Verlässlichkeit eines mobilen Knotens diskutiert. Neben einem kurzen Abriss zum Stand der Forschung in diesem Gebiet werden dazu zwei Vorschläge für die Gestaltung eines solchen Systems für mobile Ad-hoc-Netze gemacht. / The increasing deployment of mobile devices and accompanying services leads to new security challenges. Due to the changed premises caused by particular features of mobile systems, these obstacles cannot be solved solely by traditional security paradigms and mechanisms. Drawing on the example of wireless LANs, this thesis examines the development of security mechanisms for wireless ad hoc and infrastructural networks. It places special emphasis on the comprehensive protection of each single device as well as compensating missing infrastructural security means by cooperation. As a starting point this thesis analyses the characteristics of mobile environments to identify basic requirements for a security solution. Based on these requirements existing preventive, reactive and intrusion tolerant approaches are evaluated. This leads to the conception of a hybrid and universal framework to integrate arbitrary security mechanisms within cooperative formations. The resulting system design is then validated by a twofold prototype implementation. The first part consists of a distributed network intrusion detection system as an example for a security mechanism. After describing a methodology for applying anomaly- as well as misuse-based detection strategies to arbitrary network protocols, the feasibility of this approach is demonstrated for IEEE 802.11 infrastructural wireless LAN. The second part of the validation is represented by the prototype of a P2P-based cooperation middleware for collaborative intrusion detection by loosely coupled devices. Missing mechanisms for the improved mapping of overlay and physical network structures are compensated by subsequently considering the spatial position of a mobile node when choosing a cooperation partner. Furthermore, an additional interface to an external trust management system enables the establishment of trust relationships as a prerequisite for a deployment in real world scenarios. Reputation systems serve as an example of such a trust management system that can be used to estimate the reliability of a mobile node. After outlining the state of the art, two design patterns of a reputation system for mobile ad hoc networks are presented.