Advances in configurable logic technology have permitted the development of low-cost, high-speed configurable devices, allowing one or more soft processor cores to be introduced into a configurable computing system. Soft processor cores offer logic-area savings and reduced configuration times when compared to the hardware-only implementations typically used for application specific acceleration. Programs for a soft processor core are small and simple compared to the design of a hardware core, but can leverage custom hardware within the processor core to provide greater acceleration for specific applications. This thesis presents several configurable system models, and implements one such model on a Nios Embedded Processor Development Board. A software programmable and hardware configurable lightweight processor core known as the FAST CPU is introduced. The configurable system implementation attaches several FAST CPUs to a standard Nios processor to create a system for experimentation with application specific acceleration. This system incorporating the FAST CPUs was tested for bus utilization behaviour, computing performance, and execution times for a minheap application. Experimental results are compared to the performance of a software-only solution, and also with previous research results. Experimental results verify that the theory and models used to predict bus utilization are correct. Performance testing shows that the FAST CPU is approximately 25% slower than a general purpose processor, which is expected. The FAST CPU, however, is 31% smaller in terms of logic area than the general purpose processor, and is 8% smaller than the design of a hardware-only implementation of a minheap for application specific acceleration. The results verify that it is possible to move functionality from a general purpose processor to a lightweight processor, and further, to realize an increase in performance when a task is parallelized across multiple FAST CPUs. The experimentation uses a procedure by which a set of equations can be derived for predicting bus utilization and deriving a cost-benefit curve for a coprocessing entity. They are applied to a specific system in this research, but the methods are generalizable to any coprocessing entity.

Estimation of Stokes vector components from an interferometric fringe encoded image is a novel way of measuring the State Of Polarization (SOP) distribution across a scene. Imaging polarimeters employing interferometric techniques encode SOP information in a single image in the form of fringes. The lack of moving parts and the use of a single image eliminates the problems of conventional polarimetry - vibration, spurious signal generation due to artifacts, beam wander and the need for registration routines. However, interferometric polarimeters are limited by narrow band pass operation and short exposure time operations which decrease the Signal to Noise Ratio (SNR) in the detected image.A simulation environment for designing an Interferometric Stokes Imaging polarimeter (ISIP) and a detector with noise effects is created and presented. A user is capable of imaging an object with defined SOP through an ISIP on to a detector producing a digitized image output. The simulation also includes band pass imaging capabilities, control of detector noise, and object brightness levels.The Stokes images are estimated from a fringe encoded image of a scene by means of a reconstructor algorithm. A spatial domain methodology involving the idea of a unit cell and slide approach is applied to the reconstructor model developed using Mueller calculus. The validation of this methodology and effectiveness compared to a discrete approach is demonstrated with suitable examples. The pixel size required to sample the fringes and the minimum unit cell size required for reconstruction are investigated using condition numbers. The importance of the PSF of fore-optics (telescope) used in imaging the object is investigated and analyzed using a point source imaging example and a Nyquist criteria is presented.Reconstruction of fringe modulated images in the presence of noise involves choosing an optimal sized unitcell. The choice of the unit cell based on the size of the polarization domain and illumination level is analyzed using a bias-variance tradeoff to obtain the minimum root mean square error. A similar tradeoff study is used to analyze the choice of the band pass filters under various illumination levels. Finally, a sensitivity analysis of the ISIP is presented to explore the applicability of this device to detect low degrees of polarization in areas like remote sensing.

Exchange of private information over a public medium must incorporate a method for data protection against unauthorized access. Elliptic curve cryptography (ECC) has become widely accepted as an efficient mechanism to secure private data using public-key protocols. Scalar multiplication (which translates into a sequence of point operations each involving several modular arithmetic operations) is the main ECC computation, where the scalar value is secret and must be secured. In this dissertation, we consider ECC over five standard prime finite fields recommended by the National Institute of Standard and Technology (NIST), with the corresponding prime sizes of 192, 224, 256, 384, and 521 bits. This dissertation presents our general hardware-software approach and technical details of our novel hardware processor design, aimed at accelerating scalar multiplications with flexible security-performance tradeoffs. To enhance performance, our processor exploits parallelism by pipelining modular arithmetic computations and associated input/output data transfers. To enhance security, modular arithmetic computations and associated data transfers are grouped into atomically executed computational blocks, in order to make curve point operations indistinguishable and thus mask the scalar value. The flexibility of our processor is achieved through the software-controlled hardware programmability, which allows for different scenarios of computing atomic block sequences. Each scenario is characterized by a certain trade-off between the processor’s security and performance. As the best trade-off scenario is specific to the user and/or application requirements, our approach allows for such a scenario to be chosen dynamically by the system software, thus facilitating system adaptation to dynamically changing requirements. Since modular multiplications are the most critical low-level operation in ECC computations, we also propose a novel modular multiplier specifically optimized to take full advantage of the fast reduction algorithms associated with the five NIST primes. The proposed architecture has been prototyped on a Xilinx Virtex-6 FPGA and takes between 0.30 ms and 3.91 ms to perform a typical scalar multiplication. Such performance figures demonstrate both flexibility and efficiency of our proposed design and compares favourably against other systems reported in the literature. / Graduate

Chinese privet (Ligustrum sinense) is an invasive plant species in the United States (U.S.). This study utilized the most effective control measures found in the literature, and used financial analysis to identify the most cost effective management regimes to eradicate this species under different conditions. Management regimes were assessed using simulated scenarios created using six components, based on real parameters from the southern U.S.: infestation level, field coverage, stand density, herbicide application method, herbicide, and mechanical removal of privet. Financial impact on land expectation values (LEV) was analyzed and discussed for each simulated area conditions. Results suggest that the most cost effective management regime controlling privet varies according to these components. Privet control is economically feasible, and a positive LEV can be achieved for every area conditions. Finally, this study can serve as a guide to develop policies and incentives for invasive species control programs.

ABSTRACT SPATIAL AND TEMPORAL DYNAMICS OF LAND USE IMPACTS ON WATER QUALITY IN WATERSHED SYSTEMS SEPTEMBER 2007 OLGA TSVETKOVA, B.S., NOVGOROD STATE UNIVERSITY, RUSSIA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Timothy O. Randhir Predicting land use change and assessing watershed tradeoffs between the watershed system components through system simulation helps to determine future nutrient and sediment load reductions needed to obtain a particular water quality standard. This also helps to examine the tradeoffs among nutrient and sediment load reductions that achieve the same water quality objective. Tradeoff assessment is a useful tool to meet agricultural and urban needs in regard protecting water quality. The purpose of this study has been to develop and apply a spatial temporal dynamic simulation model for the land use change and a hydrologic dynamic simulation model for the estimation of the tradeoffs relationships between watershed contaminants and attributes. The Spatial – temporal dynamic model is applied to one of the subbasins within the Blackstone River Watershed to predict potential land use changes in the subbasin. Results show that the increase in urban land use in the watershed is associated with the decline in agricultural and forest land. The overall preliminary results show that urbanization could become a serious problem in the future. The results emphasize the need to protect agricultural area in rapidly changing watersheds. In the watershed tradeoffs simulation modeling, the effect of land use change on water quality is simulated using the Soil and Water Assessment Tool. The methodology is applied to the Blackstone River watershed and its 115 subbasins. Regression statistics as well as graphical techniques are used for accurate evaluation of the model. Water quality and quantity estimated using an array of equations to simulate watershed processes. It is observed that a fairly high variability exists for soluble phosphorus, mineral phosphorus, and sediment yield. The tradeoff relationships between watershed components are described by tradeoff equations and graphically. The regression results indicate that the highest correlations exist between nitrate and surface runoff and between mineral phosphorus and sediment yield. The final tradeoff matrix is developed for the study watershed and could be used to assess various policies that include policies on nutrients, water resources, and land use.

Family forests comprise a significant portion of total forest lands in the southern United States and their owners frequently have multiple, competing objectives. This research evaluated the effectiveness of functional zoning based on site index on forest sizes relevant to family forest owners. A total of fifty family forests were randomly selected from counties in the East Texas Pineywoods region. Timber production and quail habitat were used as proxies for competing objectives. It was found that 80% of family forest parcels had sufficient site index heterogeneity to benefit from functional zoning. For forest parcels that could benefit from functional zoning, the benefit in terms of increased land expectation value was not found to be dependent on parcel size. At a 5% discount rate, the average benefit of land expectation value (LEV) was $15.61 per acre. This zoning approach provides multiple objectives while minimizing the economic impact of the non-revenue objectives.

No description available.

An ever-increasing number of Internet applications, such as content and software distribution, distance learning, multimedia streaming, teleconferencing, and collaborative workspaces, need efficient and secure multicast communication. However, efficiency and security are competing requirements and balancing them to meet the application needs is still an open issue. In this thesis we study the efficiency versus security requirements tradeoffs in group key management for multicast communication. The efficiency is in terms of minimizing the group rekeying cost and the key storage cost, while security is in terms of achieving backward secrecy, forward secrecy, and resistance to collusion. We propose two new group key management schemes that balance the efficiency versus resistance to collusion. The first scheme is a flexible category-based scheme, and addresses applications where a user categorization can be done based on the user accessibility to the multicast channel. As shown by the evaluation, this scheme has a low rekeying cost and a low key storage cost for the controller, but, in certain cases, it requires a high key storage cost for the users. In an extension to the basic scheme we alleviate this latter problem. For applications where the user categorization is not feasible, we devise a cluster-based group key management. In this scheme the resistance to collusion is measured by an integer parameter. The communication and the storage requirements for the controller depend on this parameter too, and they decrease as the resistance to collusion is relaxed. The results of the analytical evaluation show that our scheme allows a fine-tuning of security versus efficiency requirements at runtime, which is not possible with the previous group key management schemes. / <p>Report code: LiU-TEK-LIC-2003:53.</p>

In order to aid federal agencies and private companies in the ever-growing problem of invasive species target detection, an investigation has been done on classification accuracy data cubes for use in the determination of spectral, spatial, and temporal sensor resolution requirements. The data cube is the result of a developed automated target recognition system that begins with ?ideal? hyperspectral data, and then reduces and combines spectral and spatial resolutions. The reduced data is subjected to testing methods using the Best Spectral Bands (BSB) and the All Spectral Bands (ASB) approaches and classification methods using nearest mean (NM), nearest neighbor (NN), and maximum likelihood (ML) classifiers. The effectiveness of the system is tested via two target-nontarget case studies, namely, terrestrial Cogongrass (Imperata cylindrica)-Johnsongrass (Sorghum halepense), and aquatic Water Hyacinth (Eichhornia crassipes)-American Lotus (Nelumbo lutea). Results reveal the effects, or trade-offs, of spectral-spatial-temporal resolution combinations on the ability of an ATR system to accurately detect the target invasive species. For example, in the aquatic vegetation case study, overall classification accuracies of around 90% or higher can be obtained during the month of August for spectral resolutions of 80 ? 1000nm FWHM for target abundances of 70 ? 100% per pixel. Furthermore, the ATR system demonstrates the use of resolution cubes that can be readily used to design or select cost-effective sensors for use in invasive species target detection, since lower resolution combinations may be acceptable in order to gain satisfactory classification accuracy results.

The recent growth in wireless communications presents a new challenge to multimedia communications. Digital image transmission is a very common form of multimedia communication. Due to limited bandwidth and broadcast nature of the wireless medium, it is necessary to compress and encrypt images before they are sent. On the other hand, it is important to efficiently utilize the limited energy in wireless devices. In a wireless device, two major sources of energy consumption are energy used for computation and energy used for transmission. Computation energy can be reduced by minimizing the time spent on compression and encryption. Transmission energy can be reduced by sending a smaller image file that is obtained by compressing the original highest quality image. Image quality is often sacrificed in the compression process. Therefore, users should have the flexibility to control the image quality to determine whether such a tradeoff is acceptable. It is also desirable for users to have control over image quality in different areas of the image so that less important areas can be compressed more, while retaining the details in important areas. To reduce computations for encryption, a partial encryption scheme can be employed to encrypt only the critical parts of an image file, without sacrificing security. This thesis proposes a scalable and secure image representation scheme that allows users to select different image quality and security levels. The binary space partitioning (BSP) tree presentation is selected because this representation allows convenient compression and scalable encryption. The Advanced Encryption Standard (AES) is chosen as the encryption algorithm because it is fast and secure. Our experimental result shows that our new tree construction method and our pruning formula reduces execution time, hence computation energy, by about 90%. Our image quality prediction model accurately predicts image quality to within 2-3dB of the actual image PSNR.