Cryptalphabet Soup: DPFs meet MPC and ZKPs

Secure multiparty computation (MPC) protocols enable multiple parties to collaborate on a computation using private inputs possessed by the different parties in the computation. At the same time, MPC protocols ensure that no participating party learns anything about the other parties’ private inputs beyond what they can infer from the computation’s output and their own inputs. MPC has wide ranging applications for privacy protecting systems. However, these systems have been plagued by limited performance, lack of scalability, and poor accuracy. In this thesis, we demonstrate several novel techniques for using distributed point functions (DPFs) in combination with MPC to obtain significant performance improvements in several different applications. Namely, using novel observations about the structure of the most efficient available DPF construction in the literature, we show that DPF keys from untrusted sources can be checked for correctness using an MPC protocol between the two key holders, with direct applications in sender-anonymous messaging. We expand these observations to produce the most efficient available method to evaluate piecewise-polynomial functions, also known as splines. The scalability and efficiency of this method allows for splines to be used for extremely high accuracy approximation of non-linear functions in MPC. Furthermore, the protocols proposed in this thesis far outperform prior solutions both in large-scale asymptotic measurements and in concrete benchmarks using high-performance software implementations at both small- and large-scale

Multi-scale sensible heat fluxes in the urban environment from large aperture scintillometry and eddy covariance

Sensible heat fluxes (QH) are determined using scintillometry and eddy covariance over a suburban area. Two large aperture scintillometers provide spatially integrated fluxes across path lengths of 2.8 km and 5.5 km over Swindon, UK. The shorter scintillometer path spans newly built residential areas and has an approximate source area of 2-4 km2, whilst the long path extends from the rural outskirts to the town centre and has a source area of around 5-10 km2. These large-scale heat fluxes are compared with local-scale eddy covariance measurements. Clear seasonal trends are revealed by the long duration of this dataset and variability in monthly QH is related to the meteorological conditions. At shorter time scales the response of QH to solar radiation often gives rise to close agreement between the measurements, but during times of rapidly changing cloud cover spatial differences in the net radiation (Q*) coincide with greater differences between heat fluxes. For clear days QH lags Q*, thus the ratio of QH to Q* increases throughout the day. In summer the observed energy partitioning is related to the vegetation fraction through use of a footprint model. The results demonstrate the value of scintillometry for integrating surface heterogeneity and offer improved understanding of the influence of anthropogenic materials on surface-atmosphere interactions

Metapopulation Genomics of American Goshawks in the Intermountain West

Understanding a species dispersal ecology and population dynamics is essential to effectively manage and conserve a species. As advancing technology improves our knowledge of species movements, it is becoming clear that many species form metapopulations to some extent. A metapopulation is a network of interconnected subpopulations that exchange reproductive individuals with subpopulations occupying nearby patches. Metapopulations have been observed in a variety of species, ranging from plants to vertebrates, and can vary greatly in their dynamics (level of connectivity and gene flow) based on the species behavior and life history strategy. Forming a metapopulation can add much resilience to the subpopulation. A steady inflow of new individuals can protect the subpopulation from inbreeding depression and adds more standing variation for natural selection to work on. However, as the metapopulation breaks down and patches become isolated, that resilience is quickly lost. Habitat fragmentation due to anthropogenic changes poses a significant danger to metapopulations. Understanding these metapopulation dynamics is of key importance to formulating effective and efficient conservation and management plans. Information such as where, when, and how these species are dispersing can tell us how to best preserve these paths and maintain the metapopulation structure. One species that forms a highly extensive metapopulation, is the American goshawk (Accipiter atricapillus). In this study we evaluated the metapopulation genomics of American goshawks in the Intermountain West by investigating the genetic diversity and differentiation, as well as gene flow and connectivity, of four subpopulations. The goshawk metapopulation is connected mainly through the natal dispersal of juveniles. Natal dispersal has been and continues to be very hard to track due the technological limitations. Here we show that genomics can offer an alternative when species cannot be easily tracked. While specific dispersal routes cannot be elucidated, we were able to discover the level and direction of gene flow between subpopulations, giving a rough idea of where and how far individuals were dispersing. We found little to no differentiation and very high gene flow between these subpopulations despite the hundreds of kilometers between them. There was no geographic structuring shown both by an isolation by distance test and a correlation test between geographic distances and the estimated number of migrants exchanged. This information is vital to understanding the species movements and ecology in order to create an effective management plan

Estimation of regional differences in wind erosion sensitivity in Hungary

In Hungary, wind erosion is one of the most serious natural hazards. Spatial and temporal variation in the factors that determine the location and intensity of wind erosion damage are not well known, nor are the regional and local sensitivities to erosion. Because of methodological challenges, no multi-factor, regional wind erosion sensitivity map is available for Hungary. The aim of this study was to develop a method to estimate the regional differences in wind erosion sensitivity and exposure in Hungary. Wind erosion sensitivity was modelled using the key factors of soil sensitivity, vegetation cover and wind erodibility as proxies. These factors were first estimated separately by factor sensitivity maps and later combined by fuzzy logic into a regional-scale wind erosion sensitivity map. Large areas were evaluated by using publicly available data sets of remotely sensed vegetation information, soil maps and meteorological data on wind speed. The resulting estimates were verified by field studies and examining the economic losses from wind erosion as compensated by the state insurance company. The spatial resolution of the resulting sensitivity map is suitable for regional applications, as identifying sensitive areas is the foundation for diverse land development control measures and implementing management activities

Algorithms for autonomous tandem operation of a dual M113 system

In mid-July 2003, the U.S. Army Tank-Automotive & Armaments Command (TACOM) performed a series of experiments at Keweenaw Research Center (KRC), with a remote operated mine roller system. This system, named Panther Lite, consists of two M113 Armored Personnel Carriers (APC’s) connected by a Tandem Vehicle Linkage Assembly (TVLA). The system has three sets of mine rollers, two of which are connected to the front of the lead vehicle with one set trailing from the trail vehicle. Currently, the system requires two joystick controllers. One regulates the braking of the tracks, throttle, and transmission of the lead vehicle and the other controls the braking and throttle of the rear vehicle. One operator controls both joysticks, attempting to maneuver the lead vehicle along a desired path. At the same time, this operator makes compensation maneuvers to reduce lateral loads in the TVLA and to guide the rear mine rollers along the desired path. The purpose of this project is to create algorithms that would allow the slave (trail) vehicle to operate using inputs that maneuver the control (lead) vehicle. The project will be completed by first reconstructing the experimental data. Kinematic models will be generated and simulations created. The models will then be correlated with the reconstructions of the experimental data. The successful completion of this project will be a first step to eliminating the need for the second joystick

A New Framework for Strategic Information Systems in Airline Industry

Stiff competition in the Airline sector mandates airlines to innovate ways to gain a competitive advantage over their rivals; however, without a strong IT the mission to attain this would be arduous. Large airlines do their best to maximise the use of enterprise systems to stream their business processes. Nonetheless, some airlines are not up to date with technology and are left with few choices when attempting to secure their existence in today’s harsh market. One option is to implement bleeding edge systems concurrently (which is our focus in this paper) due to the fact that very scant research exists regarding this phenomenon, let alone the airline sector itself. The aim of this study is explore and investigate the phenomenon of deploying multi enterprise systems concurrently due to its uniqueness and owing to the fact that this approach is not the common practice most airline undertake. We argue here that having multi Airline Solution Providers (ASP) working together concurrently to constitute a homogeneous solution generates many aspects that necessitate a deep understanding in such matters as competitor ASPs and technology leakage. In addition, the study explored various themes that unleash the phenomenon of the concurrent Multi- collaborative Enterprise Systems (MES). The role of cohesion factors that groups the rivals to work under the umbrella of an organisation was also embarked upon in this study. Various aspects contributing to the success of the MES phenomenon have been exposed with regarding ASP’s interplay, organisation, and other contextual surrounding MES. Finally, this study drew a strategic frame work for airlines that unleash the MES phenomenon. A large airline and its collaborative airline solutions provider were taken as the scope of study; the airline had over twenty six thousand employees. Five reputable world class ASPs in the airline industry in various fields were also included. The twenty five participants in this study were professionals in IT and the airline business besides being involved heavily in the phenomenon of deploying concurrent multi enterprise systems. Grounded Theory techniques were used to analyse the large volume of data gathered underpinning this by using state of art software package such as nVivo. This research has explored the phenomenon under study using grounded theory methodology to build a theoretical model that best presents the MES initiative. In addition, it has offered a well-founded framework that explains the MES phenomenon in details, which is relevant to both practitioners and researchers.This research has clearly explored and demonstrated the inhibitors and enablers in the undertaking of MES. In particular, it has focused on enablers of the organisation that received the MES. Furthermore, it has explored the interrelationship between ASPs and exposed some of the aspects that need more focus between rivals working on the same project.Royal Embassy of Saudi Arabi

Infrared and millimetre-wave scintillometry in the suburban environment – Part 1: Structure parameters

Scintillometry, a form of ground-based remote sensing, provides the capability to estimate surface heat fluxes over scales of a few hundred metres to kilometres. Measurements are spatial averages, making this technique particularly valuable over areas with moderate heterogeneity such as mixed agricultural or urban environments. In this study, we present the structure parameters of temperature and humidity, which can be related to the sensible and latent heat fluxes through similarity theory, for a suburban area in the UK. The fluxes are provided in the second paper of this two-part series. A millimetre-wave scintillometer was combined with an infrared scintillometer along a 5.5 km path over northern Swindon. The pairing of these two wavelengths offers sensitivity to both temperature and humidity fluctuations, and the correlation between wavelengths is also used to retrieve the path-averaged temperature–humidity correlation. Comparison is made with structure parameters calculated from an eddy covariance station located close to the centre of the scintillometer path. The performance of the measurement techniques under different conditions is discussed. Similar behaviour is seen between the two data sets at sub-daily timescales. For the two summer-to-winter periods presented here, similar evolution is displayed across the seasons. A higher vegetation fraction within the scintillometer source area is consistent with the lower Bowen ratio observed (midday Bowen ratio < 1) compared with more built-up areas around the eddy covariance station. The energy partitioning is further explored in the companion paper