Zugl.: Darmstadt, Techn. Univ., Diss., 2008

With gas prices rising rapidly, many people have started to believe that it has become imperative to reduce their vehicle miles travelled. Land use patterns have been found culpable of contributing to the extra VMT driven by the average. As such, urban planners have employed many strategies to attempt to reduce this portion of VMT. For example, research shows that smart growth in the form of mixed-use compact development results in a better match of jobs and housing since it brings trip origins and destinations closer, thereby making work trips shorter. This research uses spatial modeling in GIS and Multiple Linear regression/ANOVA in SPSS to analyze the link between job-housing (J/H) mismatch, land use mix and worker commute flows. The study examines J/H imbalance within a travel catchment area using a 7-mile buffer from the centroid of each census tract in Dallas County, Texas. Moreover, it uses jobs, workers local economic and community data in the form of Local Employment Dynamics, Longitudinal Employer-Household Dynamics and Quarterly Workforce Indicators provided by the US Census Bureau to carry out area profile, area comparison, distance/direction, destination, inflow/outflow and paired area analysis for workers place of work and residential distributions in Dallas county. This analysis is linked in Geographical Information Systems to the land use map, which is classified as an entropy index. The GIS results present a spatial picture of labor- shed, commute-shed, job-housing balanced and imbalanced areas by relating the land use mix and commute flows of workers in Dallas County. Moreover, MLR regression model in SPSS shows that Land use mix, Job/housing balance and housing affordability are significant predictors of mean travel time to work. This strategic tool developed through Target Area Analysis and Hot Spot Analysis will act as a guideline for land use planners to understand the regional growth complexities related to work flows. The analytical model developed can also be deployed to direct land development patterns, which will ultimately improve the quality of life, halt urban sprawl, lower costs to businesses and commuters and produce related positive externalities.

No description available.

<p>Public key encryption was first proposed by Diffie and Hellman [16], and widely popularised with the RSA cryptosystem [37]. Over the years, the security goals of public key encryption have been studied [17, 22], as have adversary models [30, 36], and many public key cryptosystems have been proposed and analysed.</p><p>It turns out that the security of many of those cryptosystems [16, 18, 22, 29, 34, 35] are based on a common class of mathematical problems, called subgroup membership problems. Cramer and Shoup [10] designed a chosen-ciphertextsecure cryptosystem based on a general subgroup membership problem (generalising their previous work [9]), and provided two new instances. Yamamura and Saito [41] defined a general subgroup membership problem, catalogued several known subgroup membership problems, and designed a private information retrieval system based on a subgroup membership problem. Nieto, Boyd and Dawson [31] designed a cryptosystem based on essentially a symmetric subgroup membership problem (see Section 4.4 and Section 6.1).</p><p>Chapter 2 and 3 contain certain preliminary discussions necessary for the later work. In Chapter 4, we discuss subgroup membership problems, both abstractly and concrete families. For all of the concrete examples, there is a related problem called the splitting problem. We discuss various elementary reductions, both abstract and for concrete families. In cryptographic applications, a third related problem, called the subgroup discrete logarithm problem, is also interesting, and we discuss this in some detail. We also discuss a variant of the subgroup membership problem where there are two subgroups that are simultaneously hard to distinguish. We prove a useful reduction (Theorem 4.11) for this case. The technique used in the proof is reused throughout the thesis.</p><p>In Chapter 5, we discuss two homomorphic cryptosystems, based on trapdoor splitting problems. This gives us a uniform description of a number of homomorphic cryptosystems, and allows us to apply the theory and results of Chapter 4 to the security of those cryptosystems.</p><p>Using the technique of Theorem 4.11, we develop a homomorphic cryptosystem that is not based on a trapdoor problem. This gives us a fairly efficient cryptosystem, with potentially useful properties.</p><p>We also discuss the security of a homomorphic cryptosystem under a nonstandard assumption. While these results are very weak, they are stronger than results obtained in the generic model.</p><p>In Chapter 6, we develop two key encapsulation methods. The first can be proven secure against passive attacks, using the same technique as in the proof of Theorem 4.11. The second method can be proven secure against active attacks in the random oracle model, but to do this, we need a certain non-standard assumption.</p><p>Finally, in Chapter 7 we discuss a small extension to the framework developed by Cramer and Shoup [10], again by essentially reusing the technique used to prove Theorem 4.11. This gives us a cryptosystem that is secure against chosen ciphertext attacks, without recourse to the random oracle model or nonstandard assumptions. The cryptosystem is quite practical, and performs quite well compared to other variants of the Cramer-Shoup cryptosystem.</p>

Status assessments are compulsory to efficacious management of large-mammal populations, particularly for endangered species such as the Florida Key deer (Odocoileus virginianus clavium). However, a dearth of data regarding basic demographic parameters has limited status assessment and management of Key deer on outer islands. Traditional survey techniques for Key deer on Big Pine and No Name keys include road-counts, strip-counts, and mark-recapture methods. However, practical limitations render traditional survey techniques impractical for application on outer islands. Thus, assessment of current status and appropriate management is limited by a paucity of information regarding Key deer on outer islands. The purpose of my study was to evaluate the utility of infrared-triggered cameras and forward-looking infrared thermography (FLIR) to monitor occupancy and abundance of Key deer on outer islands, and to obtain baseline information regarding current distribution and abundance of Key deer in these areas. In addition, I wanted to further evaluate the advantages and disadvantages inherent in using baited camera-stations to estimate abundance of large mammal populations. I compared 3 frequently applied methods to estimate abundance from camera-based survey data. All outer islands exhibited estimated abundances considerably below carrying capacities, with larger populations occurring closer to Big Pine Key. Results indicated that other islands and complexes such as Ramrod Key, Water Key, and the Annette complex maintain only small sub-populations (e.g., ≤5 individuals) and other previously inhabited island complexes (i.e., Johnson complex and Summerland Key) no longer maintain sub-populations. Additionally, I compared abundance estimates from FLIR-based surveys to camera-based estimates. Although no test of accuracy was possible, camera-based survey methods consistently produced higher estimates of Key deer abundance on outer islands. Results indicate that aerial FLIR-based survey methods may be unreliable for the survey of large mammals in tropical habitats or areas exhibiting dense vegetation, and camera-based surveys should be the preferred method to survey Key deer abundance on outer islands.

Public key encryption was first proposed by Diffie and Hellman [16], and widely popularised with the RSA cryptosystem [37]. Over the years, the security goals of public key encryption have been studied [17, 22], as have adversary models [30, 36], and many public key cryptosystems have been proposed and analysed. It turns out that the security of many of those cryptosystems [16, 18, 22, 29, 34, 35] are based on a common class of mathematical problems, called subgroup membership problems. Cramer and Shoup [10] designed a chosen-ciphertextsecure cryptosystem based on a general subgroup membership problem (generalising their previous work [9]), and provided two new instances. Yamamura and Saito [41] defined a general subgroup membership problem, catalogued several known subgroup membership problems, and designed a private information retrieval system based on a subgroup membership problem. Nieto, Boyd and Dawson [31] designed a cryptosystem based on essentially a symmetric subgroup membership problem (see Section 4.4 and Section 6.1). Chapter 2 and 3 contain certain preliminary discussions necessary for the later work. In Chapter 4, we discuss subgroup membership problems, both abstractly and concrete families. For all of the concrete examples, there is a related problem called the splitting problem. We discuss various elementary reductions, both abstract and for concrete families. In cryptographic applications, a third related problem, called the subgroup discrete logarithm problem, is also interesting, and we discuss this in some detail. We also discuss a variant of the subgroup membership problem where there are two subgroups that are simultaneously hard to distinguish. We prove a useful reduction (Theorem 4.11) for this case. The technique used in the proof is reused throughout the thesis. In Chapter 5, we discuss two homomorphic cryptosystems, based on trapdoor splitting problems. This gives us a uniform description of a number of homomorphic cryptosystems, and allows us to apply the theory and results of Chapter 4 to the security of those cryptosystems. Using the technique of Theorem 4.11, we develop a homomorphic cryptosystem that is not based on a trapdoor problem. This gives us a fairly efficient cryptosystem, with potentially useful properties. We also discuss the security of a homomorphic cryptosystem under a nonstandard assumption. While these results are very weak, they are stronger than results obtained in the generic model. In Chapter 6, we develop two key encapsulation methods. The first can be proven secure against passive attacks, using the same technique as in the proof of Theorem 4.11. The second method can be proven secure against active attacks in the random oracle model, but to do this, we need a certain non-standard assumption. Finally, in Chapter 7 we discuss a small extension to the framework developed by Cramer and Shoup [10], again by essentially reusing the technique used to prove Theorem 4.11. This gives us a cryptosystem that is secure against chosen ciphertext attacks, without recourse to the random oracle model or nonstandard assumptions. The cryptosystem is quite practical, and performs quite well compared to other variants of the Cramer-Shoup cryptosystem.

In this thesis we develop practical tools for quantum key distribution (QKD) security proofs. We apply the tools to provide security proofs for several protocols, ranging from discrete variable protocols in high dimensions, protocols with realistic implementations, measurement device independent QKD and continuous-variable QKD. The security proofs are based on the Devetak-Winter security framework [I. Devetak and A. Winter, Proc. of the Roy. Soc. of London Series A, 461, 207 (2005); B. Kraus, N. Gisin, and R. Renner, Phys. Rev. Lett., 95 080501 (2005)]. In the key rate calculation, it is often convenient to assume that the optimal attack is symmetric. Under the assumption that the parameter estimation is based on coarse-grained observations, we show that the optimal attack is symmetric, if the protocol and the postselection have sufficient symmetries. As an example we calculate the key rates of protocols using 2, d and d+1 mutually unbiased bases in d-dimensional Hilbert spaces. We investigate the connection between the optimal collective eavesdropping attack and the optimal cloning attack, in which the eavesdropper employs an optimal cloner to attack the protocol. We find that, in general, it does not hold that the optimal attack is an optimal cloner. However, there are classes of protocols, for which we can identify the optimal attack by an optimal cloner. We analyze protocols with mutually unbiased bases in d dimensions, and show that for the protocols with 2 and d+1 mutually unbiased bases the optimal attack is an optimal cloner, but for the protocols with d mutually unbiased bases, it is not. In optical implementations of the phase-encoded BB84 protocol, the bit information is usually encoded in the phase of two consecutive photon pulses generated in a Mach-Zehnder interferometer. In the actual experimental realization, the loss in the arms of the Mach-Zehnder interferometer is not balanced, for example because only one arm contains a lossy phase modulator. Since the imbalance changes the structure of the signals states and measurements, the BB84 security analysis no longer applies in this scenario. We provide a security proof for the unbalanced phase-encoded BB84. The loss does lower the key rate compared to a protocol without loss. However, for a realistic parameter regime, the same key rate is found by applying the original BB84 security analysis. Recently, the security of a measurement device-independent QKD setup with BB84 signal states was proven in Refs. [H.-K. Lo, M. Curty, and B. Qi, Phys. Rev. Lett., 108 (2012); S. L. Braunstein and S. Pirandola, Phys. Rev. Lett., 108 (2012)]. In this setup Alice and Bob send quantum states to an intermediate node, which performs the measurement, and is assumed to be controlled by Eve. We analyze the security of a measurement device-independent QKD protocol with B92 signal states, and calculate the key rates numerically for a realistic implementation. Based on our security proof we were able to prove the security of the strong reference pulse B92 protocol. We analyze the security of continuous-variable protocols using the entropic uncertainty relations established in Ref. [M. Berta, M. Christandl, R. Colbeck, J. M. Renes, and R. Renner, Nature Physics 6, 659 (2010)] to provide an estimate of the key rate based on the observed first and second moments. We analyze a protocol with squeezed coherent states and the 2-state protocol with two coherent states with opposite phases.

Conservation of native wildlife is becoming increasingly difficult due to continued human population growth and expansion. As the human population continues to increase, so does the rate of consumption of our natural resources. As competition for resources between man and wildlife continues, it is important to understand the effects of urbanization on species. Endangered Key deer (Odocoileus virginianus clavium) are endemic to the Florida Keys archipelago stretching southwest off the southern tip of peninsular Florida. Key deer range is restricted to the Lower Florida Keys with approximately 60% residing on Big Pine Key and 15% residing on No Name Key which have undergone rapid human population growth and development over the past 30 years. Urban development and its associated risk factors (i.e., habitat loss and fragmentation, deer domestication, and deer–vehicle collisions) have been cited as the greatest threat to the Key deer population. For my dissertation research, I evaluated the impacts of 30 years of development on the Key deer population. My results suggest that increased habitat fragmentation and increased road traffic have created areas of varying habitat quality and mortality risk and have resulted in a source-sink system for Key deer on Big Pine Key. In my examination of Key deer metapopulation dynamics, I found a low probability of deer colonizing 2 target outer islands (Sugarloaf and Cudjoe) through dispersal alone in the next 20 years. Further, I examined the impacts of urbanization on changes in Key deer population dynamics, behavior, and morphology. Collectively, my results suggest that over the past 30 years Key deer have become more urbanized, which in turn has influenced Key deer behavior and population viability. Behavioral adaptations due to deer plasticity appear to have provided Key deer with mechanisms to persist in a changing environment due to urbanization. However, the future ability of Key deer to persist in a continuously urbanizing environment cannot be predicted. At some threshold, urban development would become unsustainable, and, unlike other forms of habitat change or environmental disturbances, urban development is in most cases irreversible, requiring careful planning in habitat conservation strategies.

Florida Key deer (Odocoileus virginianus clavium) were listed as endangered by the U.S. Fish and Wildlife Service (USFWS) in 1967. A variety of survey methods have been used in estimating deer density and/or changes in population trends for this species since 1968; however, a need to evaluate the precision of existing and alternative survey methods (i.e., road counts, mark-recapture, infrared-triggered cameras [ITC]) was desired by USFWS. I evaluated density estimates from unbaited ITCs and road surveys. Road surveys (n = 253) were conducted along a standardized 4-km route each week between January 1999–December 2000 (total deer observed, n = 4,078). During this same period, 11 ITC stations (1 camera/42 ha) collected 5,511 deer exposures. Study results found a difference (P < 0.001) between methods with road survey estimates lower (76 deer) than ITC estimates (166 deer). Comparing the proportion of marked deer, I observed a higher (P < 0.001) proportion from road surveys (0.266) than from ITC estimates (0.146). Lower road survey estimates are attributed to (1) urban deer behavior resulting in a high proportion of marked deer observations, and (2) inadequate sample area coverage. I suggest that ITC estimates are a reliable and precise alternative to road surveys for estimating Key deer densities on outer islands. I also evaluated density estimates from 3 road survey methods. Road survey methods (n = 100) were conducted along a standardized 31-km route where markresight, strip-transect, and distance sampling data were collected between June 2003– May 2004. I found mark-resight estimates to be lower ( x = 384, 95% CI = 346–421) than strip-transect estimates ( x = 854, 95% CI = 806–902) and distance estimates ( x = 523, 95% CI = 488–557). I attribute low mark-resight estimates to urban deer behavior resulting in a higher proportion of marked deer observations along roadways. High strip-transect estimates also are attributed to urban deer behavior and a reduced effective strip width due to dense vegetation. I propose that estimates using distance sampling eliminate some of these biases, and recommend their use in the future.

Status assessments are compulsory to efficacious management of large-mammal populations, particularly for endangered species such as the Florida Key deer (Odocoileus virginianus clavium). However, a dearth of data regarding basic demographic parameters has limited status assessment and management of Key deer on outer islands. Traditional survey techniques for Key deer on Big Pine and No Name keys include road-counts, strip-counts, and mark-recapture methods. However, practical limitations render traditional survey techniques impractical for application on outer islands. Thus, assessment of current status and appropriate management is limited by a paucity of information regarding Key deer on outer islands. The purpose of my study was to evaluate the utility of infrared-triggered cameras and forward-looking infrared thermography (FLIR) to monitor occupancy and abundance of Key deer on outer islands, and to obtain baseline information regarding current distribution and abundance of Key deer in these areas. In addition, I wanted to further evaluate the advantages and disadvantages inherent in using baited camera-stations to estimate abundance of large mammal populations. I compared 3 frequently applied methods to estimate abundance from camera-based survey data. All outer islands exhibited estimated abundances considerably below carrying capacities, with larger populations occurring closer to Big Pine Key. Results indicated that other islands and complexes such as Ramrod Key, Water Key, and the Annette complex maintain only small sub-populations (e.g., ≤5 individuals) and other previously inhabited island complexes (i.e., Johnson complex and Summerland Key) no longer maintain sub-populations. Additionally, I compared abundance estimates from FLIR-based surveys to camera-based estimates. Although no test of accuracy was possible, camera-based survey methods consistently produced higher estimates of Key deer abundance on outer islands. Results indicate that aerial FLIR-based survey methods may be unreliable for the survey of large mammals in tropical habitats or areas exhibiting dense vegetation, and camera-based surveys should be the preferred method to survey Key deer abundance on outer islands.