Annual Survey of Virginia Law: Antitrust and Trade Regulation Law

During the past year, this country has devoted much attention, with good reason, to the Microsoft trial and appeal. Not since the breakup of Ma Bell\u27s stronghold on the telecommunications industry in the early 1980s has a single legal battle posed so significant a change for both an industry and its consumers. In fact, given the far-reaching effects of this decision on other related industries and consumers, it likely will be years before its ultimate impact can be assessed

Are Mergers Driven by Overvaluation? Evidence from Managerial Insider Trading Around Merger Announcements

This paper aims to understand whether “overvaluation ” is a plausible motive behind the recent merger activity by examining the insider trades of acquirer firm managers prior to merger announcements for 2,105 mergers from 1983 to 2001. If managers perceive own company stock as “overvalued ” they will be more willing to buy other firms for stock. At the same time they will be more willing to sell company stock in their personal portfolios. Using this simple prediction, I show that acquirer-firm managers abnormally increase their insider sales prior to stock mergers and bad mergers, whereas no such change is observed prior to cash mergers and good mergers. The increased willingness of managers to sell stock prior to stock mergers provides preliminary evidence for the “overvaluation” motive behind the mergers

Ad hoc network security and modeling with stochastic petri nets

Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. These networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. Unlike the existing commercial wireless systems and fixed infrastructure networks, they do not rely on specialized routers for path discovery and traffic routing. Security is an important issue in such networks. Typically, mobile nodes are significantly more susceptible to physical attacks than their wired counterparts. This research intends to investigate the ad hoc network routing security by proposing a performance enhanced Secure ad hoc On-demand Routing protocol (SOR). Specifically, it presents a method to embed Security Level into ad hoc on-demand routing protocols using node-disjoint multipath, and to use maximum hopcount to restrict the number of routing packets in a specific area. The proposed scheme enables the use of security as a marked factor to improve the relevance of the routes discovered by ad hoc routing protocols. It provides customizable security to the flow of routing protocol messages. In general, SOR offers an alternative way to implement security in on-demand routing protocols. Ad hoc network is too complex to allow analytical study for explicit performance expressions. This research presents a Stochastic Petri net-based approach to modeling and analysis of mobile ad hoc network. This work illustrates how this model is built as a scalable model and used to exploit the characteristics of the networks. The proposed scheme is a powerful analytical model that can be used to derive network performance much more easily than a simulation-based approach. Furthermore, the proposed model is extended to study the performance of ad hoc network security by adding multipath selection and security measurement parameters. This research gives a quantificational measurement to analyze the performance of a modified SPN model under the effect of multipath and attack of a hypothetical compromised node

A cross-layer implementation of Ad hoc On-demand Distance Vector routing (AODV) protocol

Mobile Ad hoc Networks (MANETs) are networks which will form the basis for the ubiquitous data access because of their ease of deployment. Due to the dynamic nature of a MANET, routing is one of the most critical elements of MANET. Routing protocols for MANET can be broadly classified as a proactive routing protocol or a reactive routing protocol. In the proactive routing protocols, mobile nodes periodically exchange routing information among themselves. Hence proactive routing protocols generate high overhead messages in the network. On the other hand, reactive routing protocols work on-demand. Thereby generating less number of overhead messages in the network compared to proactive routing protocols. But reactive routing protocols use a global search mechanism called \u27flooding\u27 during the route discovery process. \u27Flooding\u27 generates a huge number of overhead messages in the network. Those overhead messages affect the performance of reactive routing protocols in term of network throughput. That kind of performance problem is called \u27scaling\u27 problem. Ad hoc On-demand Distance Vector Routing with Cross-Layer Design (AODV-CL) protocol has been proposed to solve this scaling problem. The AODV routing protocol has been modified to implement AODV-CL protocol. AODV-CL protocol reduces \u27flooding\u27 problem of reactive routing protocols by limiting the number of nodes that should participate in route discovery process based on their status in the network and also avoiding congested area of the network. It is shown that AODV-CL protocol reduces overhead messages by 73% and reduces end-to-end delay per packet by 32% compared to regular AODV protocol. I

A comparative study of routing protocols in MANETs

Mobile Ad Hoc networks are emerging area of mobile computing. A mobile ad hoc network (MANET) is composed of mobile routers and associated hosts connected by wireless links. The routers are free to move randomly and organize themselves arbitrarily, thus, the network\u27s wireless topology may change rapidly and unpredictably. In fact, it is considered that each node would have some capacity to relay the information thus constrained by computational power, battery life and increasingly complex routing with added functionality of a router. Nodes may keep joining and leaving an ad hoc network. Such a network may operate in a stand alone fashion, or may be connected to the larger Internet. Lack of infrastructure in ad hoc networks sets new challenges for routing algorithms where the network is formed by a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. A number of routing protocols like Dynamic Source Routing (DSR), Ad Hoc On-Demand Distance Vector Routing (AODV), Destination-Sequenced Distance-Vector (DSDV), Zone Routing Protocol (ZRP) and Temporally Ordered Routing Algorithm (TORA) have been implemented. In this thesis an attempt has been made to compare the performance of prominent on-demand reactive routing protocols for mobile ad hoc networks (AODV and TORA), along with the traditional proactive DSDV protocol. Although AODV and TORA share similar on-demand behavior, the differences in the protocol mechanics can lead to significant performance differentials. The performance differentials are analyzed using varying network loads, mobilities, and network sizes. These simulations are carried out using network simulator (ns-2.1b9a) to run mobile ad hoc network simulations

Building China's high-tech telecom equipment industry : a study of strategies in technology acquisition for competitive advantage

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program, 2001.Includes bibliographical references (p. 171-175).Over the past decade, China has witnessed a rapid growth in its information and communications technology (ICT) sector. The subject of this thesis specifically focuses on the telecommunications infrastructure equipment industry in China. This sector is an interesting one to study given that some of the leading domestic companies have mostly emphasized developing their own capabilities in product development, rather than calling upon formal technology transfers through foreign direct investment (FDI) initiatives. A significant challenge faced by local firms, however, is that foreign equipment manufacturers possessing deeper technological resources dominate their domestic market. Nevertheless, Chinese enterprises have recently begun producing high-end equipment such as core/backbone routers and DWDM optical transmission systems. The basic question this thesis seeks to answer, therefore, is how can Chinese companies become technologically competitive within the high-end segments of the telecom equipment market? A case study methodology was used to address this question, focusing on two leading domestic firms: Huawei Technologies, a privately owned company, and ZTE Corporation (Zhongxing), a state-owned enterprise. The findings show that four factors have contributed to the competitiveness of domestic firms. Firstly, they are able to successfully leverage the configurational nature of communications technology. Secondly, the substantial investment made by the case study firms to develop their own R&D capabilities has enabled them to become 'close followers' of the world technological frontier. Thirdly, the global trend towards a less vertically integrated equipment industry has produced a base of suppliers from which Chinese firms can procure world-class component and subsystem technologies. Lastly, the role of the Chinese government has been instrumental in building technological capabilities at the national level and expanding market demand. Reciprocal arrangements and performance requirements established between government and domestic firms have encouraged the latter to upgrade their technological capabilities. These combined observations provide a perspective on firm competitiveness in high tech industries that is somewhat different to the models proposed under 'second mover advantage' theory. Furthermore, the analyses made of technology acquisition at the level of the firm highlight the importance of independent development (where possible), compared to FDI, as a vehicle for technological development within late industrializing economies.by Aleyn Smith-Gillespie.S.M.M.C.P