The National Park Service (NPS) is currently contemplating the implementation of a system-wide traffic monitoring program. While several of the national parks within this network collect continuous vehicle data at multiple stations within each park, these programs have not been examined for their efficiency and cost effectiveness. Therefore, as the NPS looks to expand their count program, this thesis investigates potential improvements using a sample set of five parks. To determine whether the national park seasonal and day-of-week traffic patterns exhibit consistency from one year to the next, the seasonal and day-of-week factors were compared across all five years. Using the Kruskal-Wallis test, it was determined that the seasonal and day-of-week factors were not statistically different from 2002 to 2006 for all five national parks. Therefore, it is recommended that the NPS consider reducing the amount of data that they collect by using short-duration counts in conjunction with a modest number of permanent counts. To determine whether data collection efforts can be shared amongst various entities, the national park traffic counts for 2002 to 2006 were compared to those of nearby state highway automatic traffic recorder (ATR) locations using correlation analyses. While the correlation values ranged from “high” to “negligible”, the distance between the park and ATR location had a direct effect on the magnitude of the value. Therefore, in order to achieve the greatest probability that the correlation will be “high”, it is suggested that the NPS share data collection efforts using ATR locations within 20 miles of the park. To determine which design volume calculation method was most appropriate for the parks, design volumes were computed using two methods. Using the traditional Kfactor plot, it was determined that the 30th highest hourly volumes should be used for urban parks as this is where the “knee” occurs. Although this is not the case for rural parks, there is no compelling evidence to suggest a more appropriate design hour. Additionally, the method recommended by AASHTO for recreational roadways resulted in volumes that were frequently exceeded. Therefore, the K-factor plot method is most appropriate for both the urban and rural parks.

In this dissertation, we address issues related to traffic analysis attacks and the engineering in anonymous communication networks. Mixes have been used in many anonymous communication systems and are supposed to provide countermeasures that can defeat various traffic analysis attacks. In this dissertation, we first focus on a particular class of traffic analysis attack, flow correlation attacks, by which an adversary attempts to analyze the network traffic and correlate the traffic of a flow over an input link at a mix with that over an output link of the same mix. Two classes of correlation methods are considered, namely time-domain methods and frequency-domain methods. We find that a mix with any known batching strategy may fail against flow correlation attacks in the sense that, for a given flow over an input link, the adversary can correctly determine which output link is used by the same flow. We theoretically analyze the effectiveness of a mix network under flow correlation attacks. We extend flow correlation attack to perform flow separation: The flow separation attack separates flow aggregates into either smaller aggregates or individual flows. We apply blind source separation techniques from statistical signal processing to separate the traffic in a mix network. Our experiments show that this attack is effective and scalable. By combining flow separation and frequency spectrum matching method, a passive attacker can get the traffic map of the mix network. We use a non-trivial network to show that the combined attack works. The second part of the dissertation focuses on engineering anonymous communication networks. Measures for anonymity in systems must be on one hand simple and concise, and on the other hand reflect the realities of real systems. We propose a new measure for the anonymity degree, which takes into account possible heterogeneity. We model the effectiveness of single mixes or of mix networks in terms of information leakage and measure it in terms of covert channel capacity. The relationship between the anonymity degree and information leakage is described, and an example is shown.

NetFlow is a de facto protocol to export information about IP flow from network device. In this paper, we describe the modification to the famous open source software Flow-tools which let it has the ability to process the large NetFlow data under reasonable time and resource in the first part. In second part, we propose a series network usage and anomalies analysis methods, using TANet as example. These analyses are useful for capacity planning, peering, security, usage policy enacting.

Due to projectedincrea ses in air traffic, there are several research efforts underway to evaluate ways to safely increase the capacity of the National Airspace System (NAS), improve operational efficiency, andre duce aircraft noise. At NASA Langley Research Center (LaRC) in Hampton, Virginia, two parallel research efforts have focusedon terminal area research: one is Airborne Precision Spacing (APS), and the other is the Quiet Aircraft Technologies (QAT) project. The APS objective is to increase terminal-area capacity without adversely affecting safety, whereas the QAT project objective is to develop noise- and fuel-efficient approach trajectories. The APS project developed a cockpit tool, called Airborne Merging and Spacing for Terminal Arrivals (AMSTAR), that issues speedco mmands to aircraft to maintain desired spacing between aircraft pairs. The APS studies showed an ability to increase runway capacity; however, capacity increases may negatively impact noise andemissio n levels in airport areas. The QAT project created efficient Continuous Descent Approaches (CDAs), which showedred uctions in aircraft ground noise and fuel consumption. Previous research has shown that CDA trajectories have adverse effects on runway capacity because aircraft must be spacedf urther apart at long distances from the runway to prevent separation losses at the runway threshold. To date, the APS and CDA concepts have been evaluated independently at LaRC.In this study, three different approaches to combining APS and CDA operations were evaluatedto determine the feasibility and benefits of combining these concepts. These methods combined AMSTAR with 3◦-flight-path-angle-CDA approach routes, 3◦-CDA routes with spoilers, and2 ◦-CDA routes without spoilers. Adding the use of spoilers allowedf aster responses to large speedr eductions issued by AMSTAR. This improvement was contrastedwith the effects of a shallower flight-path angle for greater deceleration capabilities. This research indicated that AMSTAR improved the performance of CDA operations, although full capacity improvements were not achieved. Whereas the 2◦-CDA routes were expectedto show the best results, the 3◦-CDA case with spoilers showed the least variability in thresholdspacing errors. All of the CDA routes were more noise, fuel, and time efficient than traditional step-descent routes that are commonly usedto day.

Security and privacy have gained more and more attention with the rapid growth and public acceptance of the Internet as a means of communication and information dissemination. Security and privacy of a computing or network system may be compromised by a variety of well-crafted attacks. In this dissertation, we address issues related to security and privacy in computer network systems. Specifically, we model and analyze a special group of network attacks, known as traffic analysis attacks, and develop and evaluate their countermeasures. Traffic analysis attacks aim to derive critical information by analyzing traffic over a network. We focus our study on two classes of traffic analysis attacks: link-load analysis attacks and flow-connectivity analysis attacks. Our research has made the following conclusions: 1. We have found that an adversary may effectively discover link load by passively analyzing selected statistics of packet inter-arrival times of traffic flows on a network link. This is true even if some commonly used countermeasures (e.g., link padding) have been deployed. We proposed an alternative effective countermeasure to counter this passive traffic analysis attack. Our extensive experimental results indicated this to be an effective approach. 2. Our newly proposed countermeasure may not be effective against active traffic analysis attacks, which an adversary may also use to discover the link load. We developed methodologies in countering these kinds of active attacks. 3. To detect the connectivity of a flow, an adversary may embed a recognizable pattern of marks into traffic flows by interference. We have proposed new countermeasures based on the digital filtering technology. Experimental results have demonstrated the effectiveness of our method. From our research, it is obvious that traffic analysis attacks present a serious challenge to the design of a secured computer network system. It is the objective of this study to develop robust but cost-effective solutions to counter link-load analysis attacks and flow-connectivity analysis attacks. It is our belief that our methodology can provide a solid foundation for studying the entire spectrum of traffic analysis attacks and their countermeasures.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 22, 2008) Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 134-144).

Thesis (M.A.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Jeanne Giraldo, Karen Guttieri. Includes bibliographical references (p. 49-52). Also available online.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Rudolph P. Darken, Joseph A. Sullivan. Includes bibliographical references (p. 41). Also available online.

Thesis--Würzburg. / Bibliography: p. 1. 5-6.