AffiliationEdwards Air Force Base
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AbstractThe Edwards Digital Switch (EDS) provides mission critical voice and time-spaceposition information (TSPI) communication switching capability to the Edwards Test Range. The present system has been in operation for about 10 years. The core of this system is based on widely used commercial-off-the-shelf (COTS) time-slot interchange switches that were designed for a 40-year service life. The application layers of the system, comprising the command/control elements and the communications and user interfaces, were custom developed by the prime contractor to satisfy the performance requirements of the Air Force Flight Test Center (AFFTC). Problems with the current system include difficulty in obtaining replacement items for equipment developed by the prime contractor and higher than expected failure rates for this equipment. Based on experience, the service life for the equipment developed by the prime contractor appears to be about 15 years. Another problem is that lower cost packet switches are taking market share from the more traditional time-slot interchange switches. This factor tends to accelerate the obsolescence of the existing COTS equipment. Solutions are being investigated to update or replace the EDS. One solution is to reuse the existing COTS core equipment and replace the present application layers, preferably with COTS. Another solution is to replace the entire system with COTS or vendormodified COTS hardware and software.
SponsorsInternational Foundation for Telemetering
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ASSESSMENT OF PHOTONIC SWITCHES AS FUTURE REPLACEMENT FOR ELECTRONIC CROSS-CONNECT SWITCHESYoussef, Ahmed H.; TYBRIN Corporation; Edwards Air Force Base (International Foundation for Telemetering, 1999-10)This paper presents the future of optical networking via photonic switches as a potential replacement for the existing electronic cross-connects. Although optical amplifiers are now mainstream and wave division multiplexing (WDM) systems are a commercial reality, the industry’s long-term vision is one of the all-optical network. This will require optical switching equipment such as all-optical or “photonic” cross-connect switches that will provide packet switching at an optical layer. Currently, as voice calls or data traffic are routed throughout Range and commercial networks, the information can travel through many fiber-optic segments which are linked together using electronic cross-connects. However, this electronic portion of the network is the bottleneck that is preventing the ideal network from achieving optimal speeds. Information is converted from light into an electronic signal, routed to the next circuit pathway, then converted back into light as it travels to the next network destination. In an all-optical network, the electronics are removed from the equation, eliminating the need to convert the signals and thereby significantly improving network performance and throughput. Removing the electronics improves network reliability and restoration speeds in the event of an outage, provides greater flexibility in network provisioning, and provides a smooth transition when migrating to future optical transmission technologies. Despite the fact that photonic switching remains uncommercialized, it now seems apparent that the core switches in both the public networks and DoD Range networks of the early 21st century will probably carry ATM cells over a photonic switching fabric.
Switching Costs, Investment, and Collusion: Essays in Empirical Industrial OrganizationShcherbakov, Oleksandr (The University of Arizona., 2008)This dissertation consists of three essays in Empirical Industrial Organization. In each essay I develop and estimate an econometric model to quantify unobserved structural parameters of the underlying theoretical model. The first study develops a dynamic model of consumer behavior in the market for paid television services. A representative consumer supply side model is then used to recover the cost structure of cable providers. Simulation of counterfactual experiments allows me to measure the effect of satellite entry on optimal cable prices. Using data on cable and satellite systems across local U.S. television markets over the period 1997-2006, I estimate parameters of the structural models. Estimation results suggest presence of significant consumer switching costs, amounting to approximately $109 and $186 (in 1997 dollars) for cable and satellite systems respectively. In the absence of satellite competitor cable prices would be on average 19 percent higher than observed ones. The second essay evaluates the degree of collusion among sugar refiners in Ukraine. I show that government regulation may facilitate collusion between the members of the association of producers. I extend the existing empirical literature on collusion by developing an empirical model of collusive behavior when the objective function of a cartel is not known. Under the assumption that a cartel implements a proportional reduction technique of collusion parameter that measures the degree of monopolization has structural interpretation. Using data from the Ukrainian manufacturing enterprise register between 1993 and 2000, I estimate the degree of monopolization in the Ukrainian sugar refining industry. Estimation results suggest moderate degree of collusion ranging between 89 and 95 percent of the Cournot equilibrium quantity. The third essay proposes an empirical model of firm level fixed capital investment when financial markets are imperfect. In this case, firms operating in a "constrained regime" cannot afford the optimal level of investment predicted by their intertemporal maximization problem. I derive investment functions for constrained and unconstrained firms from a structural dynamic model of investment. I then derive a specification for a regime switching regression with unknown sample separation and without an explicit selection equation. To estimate the structural parameters, I use Ukrainian firm-level data between 1993 and 1998. Estimation results indicate that the probability of facing financial constraints in the Ukrainian economy was very high and ranged from 0.39 in the ferrous metallurgy to 0.79 in the power industry.
Governance Reputation and the Market Reaction to the Auditor Switch and Retention DecisionRodgers, Theodore (The University of Arizona., 2006)The purpose of this dissertation is to examine the informational role of audit client (i.e. firm) reputation in the auditor switching and retention decision. I perform an experimental examination of an analytical model, prescribing the optimal choices made by firms in the decision to retain or switch auditors without considering firm reputation. Using an experimental markets approach, I provide evidence of the market reaction to a firm's switch/retention decision under two alternative treatments. In the first (baseline) treatment, an explicit test of the analytical model, firms do not incur reputation effects when making the decision to switch or retain auditors. In the second treatment, firms consider market perceptions of opportunistic auditor switching and retention and the potential effects on the firm's reputation.The choice of auditor switching and retention is a significant component of the firm's corporate governance structure. I precisely measures reputation formation and its impact on this specific governance decision by the inclusion of prior period auditor switch/retention decisions made by firms in reputation treatment conditions. Prior archival research has demonstrated a link between auditor quality and earnings quality. These studies suggest that the retention of a high-quality auditor, or dismissal of a poor-quality auditor, can signal high quality earnings to the market. The converse is also suggested; retention of a poor-quality auditor, or dismissal of a high-quality auditor, can signal poor earnings quality. The decision to retain or switch auditors is made annually by firms who have superior information over their auditors and investors. In the short run, the decision to retain or switch auditors offers a temporary signal which the market may not clearly price. However, including the firm's track record of auditor switching and retention decisions among auditors of differing quality allows for the development of a positive or negative reputation on this portion of corporate governance.The results presented provide evidence of the model's descriptive validity for the firm's optimal choices and related market reaction to the auditor switching decision for a finite time horizon. Additionally, the study examines the market reaction to a firm's reputation on the auditor switching and retention decision.