The principal-agent problem is an important model in the field of Economics of Information. In this thesis we study only a particular type of principal-agent problem which is called moral hazard model and by the principal-agent problem we mean it is moral hazard model. The moral hazard model actually belongs to the class of bilevel programming problems in Mathematics. In Economics. the first order approach is used to reduce the principal-agent problem to a single level optimization problem. However, this approach is only valid under some strong conditions. Moreover the approach can only be used under the assumption that the optimal action of the principal-agent problem and its relaxed problem appears only at an interior point. In this thesis, we consider a new relaxed problem. Under more general assumptions. we can solve the principal-agent problem without restricting the optimal action of the agent to be in the interior.

There are various kinds of noise that affects DNA array data and it is a challenge to obtain high quality data from an experiment. Background correction is a first step for DNA array data processing; however, current methods for background correction have disadvantages. In this thesis, I propose a mixture model to facilitate the background correction for DNA array data generated by ImaGene. The corresponding software is also provided.

Deficits in working memory are typical symptoms in schizophrenia. The gene for the Dopamine Receptor 1 (DRD1) is one of the candidate genes for schizophrenia, and it is critical for memory function. Magnetic Resonance Imaging (fMRI) was used to detect neurocircuitries engaged during a behavioral task of subjects with chronic schizophrenia and healthy people. Multivariate analysis in particular Partial Least Squares, was adopted to quantitatively capture diagnosis-specific patterns. The brain-behavior analyses identified diagnosis-specific circuitries that included many cortical areas. Furthermore, we compared two groups of schizophrenics with different DRD1 genotype. The imaging-genetics analysis showed that covariance patterns of different areas (including the dorsolateral prefrontal cortex and the inferior parietal lobule) were inversely related between the two genotypes. Therefore, it appears that the speed in subjects' response may be indicative of diagnostic-specific networks, and that DRD1 genotype may suggest differential use of neural networks.

The Kuiper belt is a population of planetesimals outside the orbit of Neptune. The high inclinations and eccentricities exhibited by many belt members, and its very low mass (M 0.1M) present an enigma to planetesimal accretion scenarios: the high relative encounter velocities (vrei 1 km s-1), and infrequent collisions of the largest members make the growth of Pluto-sized bodies impossible over the age of the Solar system. Accretion in the early stages of planet-building must have been in a more dense environment allowing large objects to grow before growth was halted. The current Kuiper belt population is the left-over relic of accretion, which has undergone collisional re-shaping since the epoch of accretion. The shape of the size distribution can provide constraint on the accretion timescale, the primordial Kuiper belt mass, and the collisional processing the belt has undergone. Thus, a measure of the size distribution provides one of the primary constraint on models which attempt to explain the formation of the Kuiper belt. We have performed a large-scale ecliptic Kuiper belt survey, with an aerial cov¬erage of 3.3 square degrees to a limiting magnitude m(R) 27. From these ob¬servations, we have discovered more than 100 new Kuiper belt objects. Using this survey we have provided the best measurement of the Kuiper belt luminosity function to-date, from which we have inferred the size distribution. We have found that the size distribution is well described by a power-law for large objects with a steep slope q1 = 4.8, that breaks, or rolls over to a shallower power-law with slope q2 = 2 at ob¬ject diameter ~ 60 km. The steep large object slope is indicative of a short accretion phase, lasting no more than a few 100 Myr. The large break diameter demonstrates that the Kuiper belt has undergone substantial collisional processing. We have developed a collisional evolution model which we have used to study the effects of planetesimal bombardment and disruption on the size distribution. We have found that, in the current Kuiper belt, little to no evolution is occurring, or has occurred for the observable Kuiper belt. We conclude that the large break diameter cannot be produced in the current environment over the age of the Solar system. A period of intense collisional evolution in a much more dense, and hence, more massive belt is required. These findings are consistent with accretion models; the typical finding is that growth of the largest Kuiper belt objects over the age of the Solar system requires a much more massive belt than currently observed. These results point to a history in which an initially much more massive Kuiper belt underwent a short period of quiescent accretion producing Pluto size bodies. Some event then occurred, which dynamically excited the planetesimals, producing an erosive environment which effectively halted planet growth and rapidly depleted the majority of the primordial mass. The remnant of this depletion is the Kuiper belt we observe today.

Nanoscale protein arrays have shown promise for biological and biomedical applications. Compared to traditional protein arrays, nanoarrays have the potential for higher throughput, better sensitivity, and require less sample volumes. In this thesis, protein nanoarrays were fabricated using a simple and inexpensive "natural lithography" approach. This method allows the fabrication of large-area ordered nanoparticle arrays consisting of metallic dots with tunable diameters down to 10 nm or less. The nanoparticle arrays are formed by depositing metal through the openings of colloidal monolayer polystyrene sphere masks. After removing the masks, nanoarrays remain and are exposed to further processing. COOH-terminated self-assembled monolayers (SAM) and N-hydroxysuccinimide (NHS) chemistry is used for surface functionalization. These surface modifications covalently attach proteins onto the nanoparticles. A single monolayer of immunoglobulin G (IgG) molecules is successfully attached on the functionalized surfaces and the bioactivity of the protein arrays is tested by attaching anti-IgG molecules, as a standard immunological assay. Results of fabrication trials and efforts to control nanoparticle size, spacing, and surface adhesion are described. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images of hexagonal gold nanoarrays consisting of approximately 150 nm particles and 3.5x108-1.5x109 per cm2 array density is shown, depending on the size of colloidal spheres. An increased height of approximately 6 nm characterized via scanning probe methods shows the attachment of a single monolayer of protein molecules to the nanoparticles. This was confirmed with SEM. A similar height increase was detected via AFM showing the attachment of anti-IgG molecules onto IgG functionalized particles. Potential applications of the protein nanoarrays and future work are discussed.

Activities associated with agricultural land use intensification, one of the primary sources of anthropogenic stress to aquatic ecosystems, degrade freshwater stream health and present a significant challenge to resource managers in terms of monitoring and remediation. Biomonitoring of benthic macroinvertebrates, a common method of measuring the impact of anthropogenic stress on freshwater stream health, has been used to characterize the impact of agricultural activities. However, in order for this technique to be useful to resource managers in the protection of freshwater streams from agricultural degradation, reliable methods are needed not only to determine the impact of agricultural stress on benthic macroinvertebrate communities, but also whether agriculture best management practices (BMP's) mitigate those impacts ...

Demand for Wireless Local Area Networking (WLAN) has grown significantly during the past several years. WLAN systems need to support varying data rate applications and consume low amount of energy. This work presents a reconfigurable WLAN transceiver architecture that has the following key features: Four-stage pipeline struc¬ture to increase throughput and reduce dynamic power consumption; Multiple adjustable clocks to avoid excessive handshaking and buffering between pipeline stages, Dynamic reconfigurability to support different modes of operation; and Low reconfiguration cost, in terms of energy consumption and delay, to allow for efficient frame-by-frame adaptation. We have chosen the IEEE 802.11a standard as the demonstration platform, how-ever our ideas are extendable to other WLAN standards that are based on similar communication principles. For example, the popular IEEE 802.11g standard uses the same Orthogonal Frequency Division Multiplexing (OFDM) scheme as 802.11a. Consequently, both standards require somewhat similar data processing; i.e., our design techniques remain applicable. Our proposed architecture is prototyped on Xilinx FPGA, and simulations show a relatively low power consumption in comparison with other 802.11a baseband processors.

Clusters of galaxies are the largest and most massive gravitationally bound objects in the universe. They contain several hundreds to thousands of galaxies orbiting in the gravitational potential well of the cluster. The space between galaxies is filled with a hot plasma that loses its thermal energy via X-ray emission. In the absence of heating sources in the ICM, the radiative cooling of the gas leads to a significant accumulation of cold gas in the cluster core which then should ultimately condense into stars or cold gas clouds (e.g.. Fabian 1994). However, high-resolution X-ray spectroscopy of the hot intracluster gas has revealed that there is little or no signature of significant cool gas in the cluster core. This strongly suggests that there must be other forms of heating mechanisms that offset radiative losses in the intracluster medium (ICM). In this dissertation, we focus on one of the potential heating sources in the ICM, and that involves the kinetic energy in the orbital motions of cluster galaxies. We examine in detail the effects of the heating due to dynamical friction of galaxies on the evolution of the ICM. We find that galaxy heating is immaterial in systems that are in cool core configurations with no other heating mechanisms operating in the ICM. Accordingly. dynamical friction-mediated heating can not be the only heating mechanism in galaxy clusters. The situation is, however, completely different if the systems have experienced sufficient amounts of energy input to warm or hot cores. We show that the role of dynamical friction heating in moderating radiative cooling cannot be neglected in these systems. We also address the results of the last generation of non-radiative cosmological simulations of galaxy clusters (Voit et al. 2005). According to these studies, the radial entropy distribution of the simulated clusters tends to follow a power law at large radii, with cores present in the entropy configurations of these systems at small radii. The origin of the entropy cores is presently unclear. We argue that the generation of entropy cores in non-radiative simulated clusters is the result of galaxy stirring.

A prototype rapid, high precision fan beam optical computed tomography (OptCT) scanner for three-dimensional polymer gel dosimetry of complex radiotherapy protocols has been developed. This study documents the design. construction and characterization of the system, as well as preliminary reconstructed optical attenuation images and dosimetric verification experiments. The principal goal in scanner design and implementation was to satisfy the Radiotherapy Accuracy and Precision (RTAP) criteria consisting of a spatial resolution of 1 x 1 x 1 mm3, an imaging time of 60 minutes, a dose accuracy within 3% and a precision within 1%. The scanner, which employs a sixty degree fan beam of 543 nm laser light to scan irradiated polymer gel samples up to 19 cm in cross-sectional diameter. has several defining attributes. Data acquisition for a single slice through a dosimeter is achieved in two minutes, using one signal acquisition per CT projection angle over a total of 360 projections. The effects of scatter and refraction of visible light are minimized by using the unique radial design of the matching medium tank, the concentric arrangement of a prototype, computer numerical control (CNC)-machined collimator and five Hamamatsu photodiode detector arrays for light detection. The novel tertiary collimation eliminates scattered light by 13% and improves reconstructed image contrast-to-noise ratio. Other characteristics of the scanner include: a laser power output variation of only 0.7%:, signal-to-noise ratio (SNR.) for calibration projections of up to 294:1, SNR for transmission projections through an irradiated polymer gel dosimeter of up to 161:1, a large absorbance dynamic range extending from 0.1 to 1.7 absorbance units and a spatial resolution of 0.25 mm2 in the axial plane of the scan¬ning geometry and 0.8 mm along the longitudinal z-axis of the scan plane. Images of optical attenuation coefficients and concomitant dose maps extracted from irradi¬ated, normoxic N--isopropylacylamide (NIPAM) polymer gels were used to investigate the potential of the system for dosimetric verification. Three different NIPAM gel irradiation experiments were performed and the resultant OptCT dose distributions were compared to the Eclipse® (Varian Medical Systems. Palo Alto. CA.) treatment planning system model. While the fan beam OptCT scanner provides promising ini¬tial images of reconstructed optical attenuation coefficients, its dosimetric accuracy compared to Eclipse - nominally 7% in low dose gradient regions and 5% on the field edges - constitutes the most significant area for future refinement.

My primary focus is in articulating a theory of knowledge that can support a robust, justice-driven conception of democracy and deliberation. I argue that it is not possible to achieve this task without conceiving knowledge as explicitly social in a significant way. A central focus in my argument is thus what kind of sociality is required for the epistemology of democratic deliberation to be adequate. Building on this focus, I claim that inclusive deliberation can be epistemologically transformative. My goal is an articulation of the epistemic value of inclusive deliberation - I argue that such an articulation rests upon a reconception of epistemological agencies that takes communities as the primary agents.